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linux/fs/ext4/mballoc.c
Theodore Ts'o 4c0cfebdf3 ext4: clean up mballoc criteria comments 
Line wrap and slightly clarify the comments describing mballoc's
cirtiera.

Define EXT4_MB_NUM_CRS as part of the enum, so that it will
automatically get updated when criteria is added or removed.

Also fix a potential unitialized use of 'cr' variable if
CONFIG_EXT4_DEBUG is enabled.

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2023-06-26 19:35:12 -04:00

7075 lines
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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (c) 2003-2006, Cluster File Systems, Inc, info@clusterfs.com
* Written by Alex Tomas <alex@clusterfs.com>
*/
/*
* mballoc.c contains the multiblocks allocation routines
*/
#include "ext4_jbd2.h"
#include "mballoc.h"
#include <linux/log2.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/nospec.h>
#include <linux/backing-dev.h>
#include <trace/events/ext4.h>
/*
* MUSTDO:
* - test ext4_ext_search_left() and ext4_ext_search_right()
* - search for metadata in few groups
*
* TODO v4:
* - normalization should take into account whether file is still open
* - discard preallocations if no free space left (policy?)
* - don't normalize tails
* - quota
* - reservation for superuser
*
* TODO v3:
* - bitmap read-ahead (proposed by Oleg Drokin aka green)
* - track min/max extents in each group for better group selection
* - mb_mark_used() may allocate chunk right after splitting buddy
* - tree of groups sorted by number of free blocks
* - error handling
*/
/*
* The allocation request involve request for multiple number of blocks
* near to the goal(block) value specified.
*
* During initialization phase of the allocator we decide to use the
* group preallocation or inode preallocation depending on the size of
* the file. The size of the file could be the resulting file size we
* would have after allocation, or the current file size, which ever
* is larger. If the size is less than sbi->s_mb_stream_request we
* select to use the group preallocation. The default value of
* s_mb_stream_request is 16 blocks. This can also be tuned via
* /sys/fs/ext4/<partition>/mb_stream_req. The value is represented in
* terms of number of blocks.
*
* The main motivation for having small file use group preallocation is to
* ensure that we have small files closer together on the disk.
*
* First stage the allocator looks at the inode prealloc list,
* ext4_inode_info->i_prealloc_list, which contains list of prealloc
* spaces for this particular inode. The inode prealloc space is
* represented as:
*
* pa_lstart -> the logical start block for this prealloc space
* pa_pstart -> the physical start block for this prealloc space
* pa_len -> length for this prealloc space (in clusters)
* pa_free -> free space available in this prealloc space (in clusters)
*
* The inode preallocation space is used looking at the _logical_ start
* block. If only the logical file block falls within the range of prealloc
* space we will consume the particular prealloc space. This makes sure that
* we have contiguous physical blocks representing the file blocks
*
* The important thing to be noted in case of inode prealloc space is that
* we don't modify the values associated to inode prealloc space except
* pa_free.
*
* If we are not able to find blocks in the inode prealloc space and if we
* have the group allocation flag set then we look at the locality group
* prealloc space. These are per CPU prealloc list represented as
*
* ext4_sb_info.s_locality_groups[smp_processor_id()]
*
* The reason for having a per cpu locality group is to reduce the contention
* between CPUs. It is possible to get scheduled at this point.
*
* The locality group prealloc space is used looking at whether we have
* enough free space (pa_free) within the prealloc space.
*
* If we can't allocate blocks via inode prealloc or/and locality group
* prealloc then we look at the buddy cache. The buddy cache is represented
* by ext4_sb_info.s_buddy_cache (struct inode) whose file offset gets
* mapped to the buddy and bitmap information regarding different
* groups. The buddy information is attached to buddy cache inode so that
* we can access them through the page cache. The information regarding
* each group is loaded via ext4_mb_load_buddy. The information involve
* block bitmap and buddy information. The information are stored in the
* inode as:
*
* { page }
* [ group 0 bitmap][ group 0 buddy] [group 1][ group 1]...
*
*
* one block each for bitmap and buddy information. So for each group we
* take up 2 blocks. A page can contain blocks_per_page (PAGE_SIZE /
* blocksize) blocks. So it can have information regarding groups_per_page
* which is blocks_per_page/2
*
* The buddy cache inode is not stored on disk. The inode is thrown
* away when the filesystem is unmounted.
*
* We look for count number of blocks in the buddy cache. If we were able
* to locate that many free blocks we return with additional information
* regarding rest of the contiguous physical block available
*
* Before allocating blocks via buddy cache we normalize the request
* blocks. This ensure we ask for more blocks that we needed. The extra
* blocks that we get after allocation is added to the respective prealloc
* list. In case of inode preallocation we follow a list of heuristics
* based on file size. This can be found in ext4_mb_normalize_request. If
* we are doing a group prealloc we try to normalize the request to
* sbi->s_mb_group_prealloc. The default value of s_mb_group_prealloc is
* dependent on the cluster size; for non-bigalloc file systems, it is
* 512 blocks. This can be tuned via
* /sys/fs/ext4/<partition>/mb_group_prealloc. The value is represented in
* terms of number of blocks. If we have mounted the file system with -O
* stripe=<value> option the group prealloc request is normalized to the
* smallest multiple of the stripe value (sbi->s_stripe) which is
* greater than the default mb_group_prealloc.
*
* If "mb_optimize_scan" mount option is set, we maintain in memory group info
* structures in two data structures:
*
* 1) Array of largest free order lists (sbi->s_mb_largest_free_orders)
*
* Locking: sbi->s_mb_largest_free_orders_locks(array of rw locks)
*
* This is an array of lists where the index in the array represents the
* largest free order in the buddy bitmap of the participating group infos of
* that list. So, there are exactly MB_NUM_ORDERS(sb) (which means total
* number of buddy bitmap orders possible) number of lists. Group-infos are
* placed in appropriate lists.
*
* 2) Average fragment size lists (sbi->s_mb_avg_fragment_size)
*
* Locking: sbi->s_mb_avg_fragment_size_locks(array of rw locks)
*
* This is an array of lists where in the i-th list there are groups with
* average fragment size >= 2^i and < 2^(i+1). The average fragment size
* is computed as ext4_group_info->bb_free / ext4_group_info->bb_fragments.
* Note that we don't bother with a special list for completely empty groups
* so we only have MB_NUM_ORDERS(sb) lists.
*
* When "mb_optimize_scan" mount option is set, mballoc consults the above data
* structures to decide the order in which groups are to be traversed for
* fulfilling an allocation request.
*
* At CR_POWER2_ALIGNED , we look for groups which have the largest_free_order
* >= the order of the request. We directly look at the largest free order list
* in the data structure (1) above where largest_free_order = order of the
* request. If that list is empty, we look at remaining list in the increasing
* order of largest_free_order. This allows us to perform CR_POWER2_ALIGNED
* lookup in O(1) time.
*
* At CR_GOAL_LEN_FAST, we only consider groups where
* average fragment size > request size. So, we lookup a group which has average
* fragment size just above or equal to request size using our average fragment
* size group lists (data structure 2) in O(1) time.
*
* At CR_BEST_AVAIL_LEN, we aim to optimize allocations which can't be satisfied
* in CR_GOAL_LEN_FAST. The fact that we couldn't find a group in
* CR_GOAL_LEN_FAST suggests that there is no BG that has avg
* fragment size > goal length. So before falling to the slower
* CR_GOAL_LEN_SLOW, in CR_BEST_AVAIL_LEN we proactively trim goal length and
* then use the same fragment lists as CR_GOAL_LEN_FAST to find a BG with a big
* enough average fragment size. This increases the chances of finding a
* suitable block group in O(1) time and results in faster allocation at the
* cost of reduced size of allocation.
*
* If "mb_optimize_scan" mount option is not set, mballoc traverses groups in
* linear order which requires O(N) search time for each CR_POWER2_ALIGNED and
* CR_GOAL_LEN_FAST phase.
*
* The regular allocator (using the buddy cache) supports a few tunables.
*
* /sys/fs/ext4/<partition>/mb_min_to_scan
* /sys/fs/ext4/<partition>/mb_max_to_scan
* /sys/fs/ext4/<partition>/mb_order2_req
* /sys/fs/ext4/<partition>/mb_linear_limit
*
* The regular allocator uses buddy scan only if the request len is power of
* 2 blocks and the order of allocation is >= sbi->s_mb_order2_reqs. The
* value of s_mb_order2_reqs can be tuned via
* /sys/fs/ext4/<partition>/mb_order2_req. If the request len is equal to
* stripe size (sbi->s_stripe), we try to search for contiguous block in
* stripe size. This should result in better allocation on RAID setups. If
* not, we search in the specific group using bitmap for best extents. The
* tunable min_to_scan and max_to_scan control the behaviour here.
* min_to_scan indicate how long the mballoc __must__ look for a best
* extent and max_to_scan indicates how long the mballoc __can__ look for a
* best extent in the found extents. Searching for the blocks starts with
* the group specified as the goal value in allocation context via
* ac_g_ex. Each group is first checked based on the criteria whether it
* can be used for allocation. ext4_mb_good_group explains how the groups are
* checked.
*
* When "mb_optimize_scan" is turned on, as mentioned above, the groups may not
* get traversed linearly. That may result in subsequent allocations being not
* close to each other. And so, the underlying device may get filled up in a
* non-linear fashion. While that may not matter on non-rotational devices, for
* rotational devices that may result in higher seek times. "mb_linear_limit"
* tells mballoc how many groups mballoc should search linearly before
* performing consulting above data structures for more efficient lookups. For
* non rotational devices, this value defaults to 0 and for rotational devices
* this is set to MB_DEFAULT_LINEAR_LIMIT.
*
* Both the prealloc space are getting populated as above. So for the first
* request we will hit the buddy cache which will result in this prealloc
* space getting filled. The prealloc space is then later used for the
* subsequent request.
*/
/*
* mballoc operates on the following data:
* - on-disk bitmap
* - in-core buddy (actually includes buddy and bitmap)
* - preallocation descriptors (PAs)
*
* there are two types of preallocations:
* - inode
* assiged to specific inode and can be used for this inode only.
* it describes part of inode's space preallocated to specific
* physical blocks. any block from that preallocated can be used
* independent. the descriptor just tracks number of blocks left
* unused. so, before taking some block from descriptor, one must
* make sure corresponded logical block isn't allocated yet. this
* also means that freeing any block within descriptor's range
* must discard all preallocated blocks.
* - locality group
* assigned to specific locality group which does not translate to
* permanent set of inodes: inode can join and leave group. space
* from this type of preallocation can be used for any inode. thus
* it's consumed from the beginning to the end.
*
* relation between them can be expressed as:
* in-core buddy = on-disk bitmap + preallocation descriptors
*
* this mean blocks mballoc considers used are:
* - allocated blocks (persistent)
* - preallocated blocks (non-persistent)
*
* consistency in mballoc world means that at any time a block is either
* free or used in ALL structures. notice: "any time" should not be read
* literally -- time is discrete and delimited by locks.
*
* to keep it simple, we don't use block numbers, instead we count number of
* blocks: how many blocks marked used/free in on-disk bitmap, buddy and PA.
*
* all operations can be expressed as:
* - init buddy: buddy = on-disk + PAs
* - new PA: buddy += N; PA = N
* - use inode PA: on-disk += N; PA -= N
* - discard inode PA buddy -= on-disk - PA; PA = 0
* - use locality group PA on-disk += N; PA -= N
* - discard locality group PA buddy -= PA; PA = 0
* note: 'buddy -= on-disk - PA' is used to show that on-disk bitmap
* is used in real operation because we can't know actual used
* bits from PA, only from on-disk bitmap
*
* if we follow this strict logic, then all operations above should be atomic.
* given some of them can block, we'd have to use something like semaphores
* killing performance on high-end SMP hardware. let's try to relax it using
* the following knowledge:
* 1) if buddy is referenced, it's already initialized
* 2) while block is used in buddy and the buddy is referenced,
* nobody can re-allocate that block
* 3) we work on bitmaps and '+' actually means 'set bits'. if on-disk has
* bit set and PA claims same block, it's OK. IOW, one can set bit in
* on-disk bitmap if buddy has same bit set or/and PA covers corresponded
* block
*
* so, now we're building a concurrency table:
* - init buddy vs.
* - new PA
* blocks for PA are allocated in the buddy, buddy must be referenced
* until PA is linked to allocation group to avoid concurrent buddy init
* - use inode PA
* we need to make sure that either on-disk bitmap or PA has uptodate data
* given (3) we care that PA-=N operation doesn't interfere with init
* - discard inode PA
* the simplest way would be to have buddy initialized by the discard
* - use locality group PA
* again PA-=N must be serialized with init
* - discard locality group PA
* the simplest way would be to have buddy initialized by the discard
* - new PA vs.
* - use inode PA
* i_data_sem serializes them
* - discard inode PA
* discard process must wait until PA isn't used by another process
* - use locality group PA
* some mutex should serialize them
* - discard locality group PA
* discard process must wait until PA isn't used by another process
* - use inode PA
* - use inode PA
* i_data_sem or another mutex should serializes them
* - discard inode PA
* discard process must wait until PA isn't used by another process
* - use locality group PA
* nothing wrong here -- they're different PAs covering different blocks
* - discard locality group PA
* discard process must wait until PA isn't used by another process
*
* now we're ready to make few consequences:
* - PA is referenced and while it is no discard is possible
* - PA is referenced until block isn't marked in on-disk bitmap
* - PA changes only after on-disk bitmap
* - discard must not compete with init. either init is done before
* any discard or they're serialized somehow
* - buddy init as sum of on-disk bitmap and PAs is done atomically
*
* a special case when we've used PA to emptiness. no need to modify buddy
* in this case, but we should care about concurrent init
*
*/
/*
* Logic in few words:
*
* - allocation:
* load group
* find blocks
* mark bits in on-disk bitmap
* release group
*
* - use preallocation:
* find proper PA (per-inode or group)
* load group
* mark bits in on-disk bitmap
* release group
* release PA
*
* - free:
* load group
* mark bits in on-disk bitmap
* release group
*
* - discard preallocations in group:
* mark PAs deleted
* move them onto local list
* load on-disk bitmap
* load group
* remove PA from object (inode or locality group)
* mark free blocks in-core
*
* - discard inode's preallocations:
*/
/*
* Locking rules
*
* Locks:
* - bitlock on a group (group)
* - object (inode/locality) (object)
* - per-pa lock (pa)
* - cr_power2_aligned lists lock (cr_power2_aligned)
* - cr_goal_len_fast lists lock (cr_goal_len_fast)
*
* Paths:
* - new pa
* object
* group
*
* - find and use pa:
* pa
*
* - release consumed pa:
* pa
* group
* object
*
* - generate in-core bitmap:
* group
* pa
*
* - discard all for given object (inode, locality group):
* object
* pa
* group
*
* - discard all for given group:
* group
* pa
* group
* object
*
* - allocation path (ext4_mb_regular_allocator)
* group
* cr_power2_aligned/cr_goal_len_fast
*/
static struct kmem_cache *ext4_pspace_cachep;
static struct kmem_cache *ext4_ac_cachep;
static struct kmem_cache *ext4_free_data_cachep;
/* We create slab caches for groupinfo data structures based on the
* superblock block size. There will be one per mounted filesystem for
* each unique s_blocksize_bits */
#define NR_GRPINFO_CACHES 8
static struct kmem_cache *ext4_groupinfo_caches[NR_GRPINFO_CACHES];
static const char * const ext4_groupinfo_slab_names[NR_GRPINFO_CACHES] = {
"ext4_groupinfo_1k", "ext4_groupinfo_2k", "ext4_groupinfo_4k",
"ext4_groupinfo_8k", "ext4_groupinfo_16k", "ext4_groupinfo_32k",
"ext4_groupinfo_64k", "ext4_groupinfo_128k"
};
static void ext4_mb_generate_from_pa(struct super_block *sb, void *bitmap,
ext4_group_t group);
static void ext4_mb_generate_from_freelist(struct super_block *sb, void *bitmap,
ext4_group_t group);
static void ext4_mb_new_preallocation(struct ext4_allocation_context *ac);
static bool ext4_mb_good_group(struct ext4_allocation_context *ac,
ext4_group_t group, enum criteria cr);
static int ext4_try_to_trim_range(struct super_block *sb,
struct ext4_buddy *e4b, ext4_grpblk_t start,
ext4_grpblk_t max, ext4_grpblk_t minblocks);
/*
* The algorithm using this percpu seq counter goes below:
* 1. We sample the percpu discard_pa_seq counter before trying for block
* allocation in ext4_mb_new_blocks().
* 2. We increment this percpu discard_pa_seq counter when we either allocate
* or free these blocks i.e. while marking those blocks as used/free in
* mb_mark_used()/mb_free_blocks().
* 3. We also increment this percpu seq counter when we successfully identify
* that the bb_prealloc_list is not empty and hence proceed for discarding
* of those PAs inside ext4_mb_discard_group_preallocations().
*
* Now to make sure that the regular fast path of block allocation is not
* affected, as a small optimization we only sample the percpu seq counter
* on that cpu. Only when the block allocation fails and when freed blocks
* found were 0, that is when we sample percpu seq counter for all cpus using
* below function ext4_get_discard_pa_seq_sum(). This happens after making
* sure that all the PAs on grp->bb_prealloc_list got freed or if it's empty.
*/
static DEFINE_PER_CPU(u64, discard_pa_seq);
static inline u64 ext4_get_discard_pa_seq_sum(void)
{
int __cpu;
u64 __seq = 0;
for_each_possible_cpu(__cpu)
__seq += per_cpu(discard_pa_seq, __cpu);
return __seq;
}
static inline void *mb_correct_addr_and_bit(int *bit, void *addr)
{
#if BITS_PER_LONG == 64
*bit += ((unsigned long) addr & 7UL) << 3;
addr = (void *) ((unsigned long) addr & ~7UL);
#elif BITS_PER_LONG == 32
*bit += ((unsigned long) addr & 3UL) << 3;
addr = (void *) ((unsigned long) addr & ~3UL);
#else
#error "how many bits you are?!"
#endif
return addr;
}
static inline int mb_test_bit(int bit, void *addr)
{
/*
* ext4_test_bit on architecture like powerpc
* needs unsigned long aligned address
*/
addr = mb_correct_addr_and_bit(&bit, addr);
return ext4_test_bit(bit, addr);
}
static inline void mb_set_bit(int bit, void *addr)
{
addr = mb_correct_addr_and_bit(&bit, addr);
ext4_set_bit(bit, addr);
}
static inline void mb_clear_bit(int bit, void *addr)
{
addr = mb_correct_addr_and_bit(&bit, addr);
ext4_clear_bit(bit, addr);
}
static inline int mb_test_and_clear_bit(int bit, void *addr)
{
addr = mb_correct_addr_and_bit(&bit, addr);
return ext4_test_and_clear_bit(bit, addr);
}
static inline int mb_find_next_zero_bit(void *addr, int max, int start)
{
int fix = 0, ret, tmpmax;
addr = mb_correct_addr_and_bit(&fix, addr);
tmpmax = max + fix;
start += fix;
ret = ext4_find_next_zero_bit(addr, tmpmax, start) - fix;
if (ret > max)
return max;
return ret;
}
static inline int mb_find_next_bit(void *addr, int max, int start)
{
int fix = 0, ret, tmpmax;
addr = mb_correct_addr_and_bit(&fix, addr);
tmpmax = max + fix;
start += fix;
ret = ext4_find_next_bit(addr, tmpmax, start) - fix;
if (ret > max)
return max;
return ret;
}
static void *mb_find_buddy(struct ext4_buddy *e4b, int order, int *max)
{
char *bb;
BUG_ON(e4b->bd_bitmap == e4b->bd_buddy);
BUG_ON(max == NULL);
if (order > e4b->bd_blkbits + 1) {
*max = 0;
return NULL;
}
/* at order 0 we see each particular block */
if (order == 0) {
*max = 1 << (e4b->bd_blkbits + 3);
return e4b->bd_bitmap;
}
bb = e4b->bd_buddy + EXT4_SB(e4b->bd_sb)->s_mb_offsets[order];
*max = EXT4_SB(e4b->bd_sb)->s_mb_maxs[order];
return bb;
}
#ifdef DOUBLE_CHECK
static void mb_free_blocks_double(struct inode *inode, struct ext4_buddy *e4b,
int first, int count)
{
int i;
struct super_block *sb = e4b->bd_sb;
if (unlikely(e4b->bd_info->bb_bitmap == NULL))
return;
assert_spin_locked(ext4_group_lock_ptr(sb, e4b->bd_group));
for (i = 0; i < count; i++) {
if (!mb_test_bit(first + i, e4b->bd_info->bb_bitmap)) {
ext4_fsblk_t blocknr;
blocknr = ext4_group_first_block_no(sb, e4b->bd_group);
blocknr += EXT4_C2B(EXT4_SB(sb), first + i);
ext4_grp_locked_error(sb, e4b->bd_group,
inode ? inode->i_ino : 0,
blocknr,
"freeing block already freed "
"(bit %u)",
first + i);
ext4_mark_group_bitmap_corrupted(sb, e4b->bd_group,
EXT4_GROUP_INFO_BBITMAP_CORRUPT);
}
mb_clear_bit(first + i, e4b->bd_info->bb_bitmap);
}
}
static void mb_mark_used_double(struct ext4_buddy *e4b, int first, int count)
{
int i;
if (unlikely(e4b->bd_info->bb_bitmap == NULL))
return;
assert_spin_locked(ext4_group_lock_ptr(e4b->bd_sb, e4b->bd_group));
for (i = 0; i < count; i++) {
BUG_ON(mb_test_bit(first + i, e4b->bd_info->bb_bitmap));
mb_set_bit(first + i, e4b->bd_info->bb_bitmap);
}
}
static void mb_cmp_bitmaps(struct ext4_buddy *e4b, void *bitmap)
{
if (unlikely(e4b->bd_info->bb_bitmap == NULL))
return;
if (memcmp(e4b->bd_info->bb_bitmap, bitmap, e4b->bd_sb->s_blocksize)) {
unsigned char *b1, *b2;
int i;
b1 = (unsigned char *) e4b->bd_info->bb_bitmap;
b2 = (unsigned char *) bitmap;
for (i = 0; i < e4b->bd_sb->s_blocksize; i++) {
if (b1[i] != b2[i]) {
ext4_msg(e4b->bd_sb, KERN_ERR,
"corruption in group %u "
"at byte %u(%u): %x in copy != %x "
"on disk/prealloc",
e4b->bd_group, i, i * 8, b1[i], b2[i]);
BUG();
}
}
}
}
static void mb_group_bb_bitmap_alloc(struct super_block *sb,
struct ext4_group_info *grp, ext4_group_t group)
{
struct buffer_head *bh;
grp->bb_bitmap = kmalloc(sb->s_blocksize, GFP_NOFS);
if (!grp->bb_bitmap)
return;
bh = ext4_read_block_bitmap(sb, group);
if (IS_ERR_OR_NULL(bh)) {
kfree(grp->bb_bitmap);
grp->bb_bitmap = NULL;
return;
}
memcpy(grp->bb_bitmap, bh->b_data, sb->s_blocksize);
put_bh(bh);
}
static void mb_group_bb_bitmap_free(struct ext4_group_info *grp)
{
kfree(grp->bb_bitmap);
}
#else
static inline void mb_free_blocks_double(struct inode *inode,
struct ext4_buddy *e4b, int first, int count)
{
return;
}
static inline void mb_mark_used_double(struct ext4_buddy *e4b,
int first, int count)
{
return;
}
static inline void mb_cmp_bitmaps(struct ext4_buddy *e4b, void *bitmap)
{
return;
}
static inline void mb_group_bb_bitmap_alloc(struct super_block *sb,
struct ext4_group_info *grp, ext4_group_t group)
{
return;
}
static inline void mb_group_bb_bitmap_free(struct ext4_group_info *grp)
{
return;
}
#endif
#ifdef AGGRESSIVE_CHECK
#define MB_CHECK_ASSERT(assert) \
do { \
if (!(assert)) { \
printk(KERN_EMERG \
"Assertion failure in %s() at %s:%d: \"%s\"\n", \
function, file, line, # assert); \
BUG(); \
} \
} while (0)
static int __mb_check_buddy(struct ext4_buddy *e4b, char *file,
const char *function, int line)
{
struct super_block *sb = e4b->bd_sb;
int order = e4b->bd_blkbits + 1;
int max;
int max2;
int i;
int j;
int k;
int count;
struct ext4_group_info *grp;
int fragments = 0;
int fstart;
struct list_head *cur;
void *buddy;
void *buddy2;
if (e4b->bd_info->bb_check_counter++ % 10)
return 0;
while (order > 1) {
buddy = mb_find_buddy(e4b, order, &max);
MB_CHECK_ASSERT(buddy);
buddy2 = mb_find_buddy(e4b, order - 1, &max2);
MB_CHECK_ASSERT(buddy2);
MB_CHECK_ASSERT(buddy != buddy2);
MB_CHECK_ASSERT(max * 2 == max2);
count = 0;
for (i = 0; i < max; i++) {
if (mb_test_bit(i, buddy)) {
/* only single bit in buddy2 may be 0 */
if (!mb_test_bit(i << 1, buddy2)) {
MB_CHECK_ASSERT(
mb_test_bit((i<<1)+1, buddy2));
}
continue;
}
/* both bits in buddy2 must be 1 */
MB_CHECK_ASSERT(mb_test_bit(i << 1, buddy2));
MB_CHECK_ASSERT(mb_test_bit((i << 1) + 1, buddy2));
for (j = 0; j < (1 << order); j++) {
k = (i * (1 << order)) + j;
MB_CHECK_ASSERT(
!mb_test_bit(k, e4b->bd_bitmap));
}
count++;
}
MB_CHECK_ASSERT(e4b->bd_info->bb_counters[order] == count);
order--;
}
fstart = -1;
buddy = mb_find_buddy(e4b, 0, &max);
for (i = 0; i < max; i++) {
if (!mb_test_bit(i, buddy)) {
MB_CHECK_ASSERT(i >= e4b->bd_info->bb_first_free);
if (fstart == -1) {
fragments++;
fstart = i;
}
continue;
}
fstart = -1;
/* check used bits only */
for (j = 0; j < e4b->bd_blkbits + 1; j++) {
buddy2 = mb_find_buddy(e4b, j, &max2);
k = i >> j;
MB_CHECK_ASSERT(k < max2);
MB_CHECK_ASSERT(mb_test_bit(k, buddy2));
}
}
MB_CHECK_ASSERT(!EXT4_MB_GRP_NEED_INIT(e4b->bd_info));
MB_CHECK_ASSERT(e4b->bd_info->bb_fragments == fragments);
grp = ext4_get_group_info(sb, e4b->bd_group);
if (!grp)
return NULL;
list_for_each(cur, &grp->bb_prealloc_list) {
ext4_group_t groupnr;
struct ext4_prealloc_space *pa;
pa = list_entry(cur, struct ext4_prealloc_space, pa_group_list);
ext4_get_group_no_and_offset(sb, pa->pa_pstart, &groupnr, &k);
MB_CHECK_ASSERT(groupnr == e4b->bd_group);
for (i = 0; i < pa->pa_len; i++)
MB_CHECK_ASSERT(mb_test_bit(k + i, buddy));
}
return 0;
}
#undef MB_CHECK_ASSERT
#define mb_check_buddy(e4b) __mb_check_buddy(e4b, \
__FILE__, __func__, __LINE__)
#else
#define mb_check_buddy(e4b)
#endif
/*
* Divide blocks started from @first with length @len into
* smaller chunks with power of 2 blocks.
* Clear the bits in bitmap which the blocks of the chunk(s) covered,
* then increase bb_counters[] for corresponded chunk size.
*/
static void ext4_mb_mark_free_simple(struct super_block *sb,
void *buddy, ext4_grpblk_t first, ext4_grpblk_t len,
struct ext4_group_info *grp)
{
struct ext4_sb_info *sbi = EXT4_SB(sb);
ext4_grpblk_t min;
ext4_grpblk_t max;
ext4_grpblk_t chunk;
unsigned int border;
BUG_ON(len > EXT4_CLUSTERS_PER_GROUP(sb));
border = 2 << sb->s_blocksize_bits;
while (len > 0) {
/* find how many blocks can be covered since this position */
max = ffs(first | border) - 1;
/* find how many blocks of power 2 we need to mark */
min = fls(len) - 1;
if (max < min)
min = max;
chunk = 1 << min;
/* mark multiblock chunks only */
grp->bb_counters[min]++;
if (min > 0)
mb_clear_bit(first >> min,
buddy + sbi->s_mb_offsets[min]);
len -= chunk;
first += chunk;
}
}
static int mb_avg_fragment_size_order(struct super_block *sb, ext4_grpblk_t len)
{
int order;
/*
* We don't bother with a special lists groups with only 1 block free
* extents and for completely empty groups.
*/
order = fls(len) - 2;
if (order < 0)
return 0;
if (order == MB_NUM_ORDERS(sb))
order--;
return order;
}
/* Move group to appropriate avg_fragment_size list */
static void
mb_update_avg_fragment_size(struct super_block *sb, struct ext4_group_info *grp)
{
struct ext4_sb_info *sbi = EXT4_SB(sb);
int new_order;
if (!test_opt2(sb, MB_OPTIMIZE_SCAN) || grp->bb_free == 0)
return;
new_order = mb_avg_fragment_size_order(sb,
grp->bb_free / grp->bb_fragments);
if (new_order == grp->bb_avg_fragment_size_order)
return;
if (grp->bb_avg_fragment_size_order != -1) {
write_lock(&sbi->s_mb_avg_fragment_size_locks[
grp->bb_avg_fragment_size_order]);
list_del(&grp->bb_avg_fragment_size_node);
write_unlock(&sbi->s_mb_avg_fragment_size_locks[
grp->bb_avg_fragment_size_order]);
}
grp->bb_avg_fragment_size_order = new_order;
write_lock(&sbi->s_mb_avg_fragment_size_locks[
grp->bb_avg_fragment_size_order]);
list_add_tail(&grp->bb_avg_fragment_size_node,
&sbi->s_mb_avg_fragment_size[grp->bb_avg_fragment_size_order]);
write_unlock(&sbi->s_mb_avg_fragment_size_locks[
grp->bb_avg_fragment_size_order]);
}
/*
* Choose next group by traversing largest_free_order lists. Updates *new_cr if
* cr level needs an update.
*/
static void ext4_mb_choose_next_group_p2_aligned(struct ext4_allocation_context *ac,
enum criteria *new_cr, ext4_group_t *group, ext4_group_t ngroups)
{
struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
struct ext4_group_info *iter, *grp;
int i;
if (ac->ac_status == AC_STATUS_FOUND)
return;
if (unlikely(sbi->s_mb_stats && ac->ac_flags & EXT4_MB_CR_POWER2_ALIGNED_OPTIMIZED))
atomic_inc(&sbi->s_bal_p2_aligned_bad_suggestions);
grp = NULL;
for (i = ac->ac_2order; i < MB_NUM_ORDERS(ac->ac_sb); i++) {
if (list_empty(&sbi->s_mb_largest_free_orders[i]))
continue;
read_lock(&sbi->s_mb_largest_free_orders_locks[i]);
if (list_empty(&sbi->s_mb_largest_free_orders[i])) {
read_unlock(&sbi->s_mb_largest_free_orders_locks[i]);
continue;
}
grp = NULL;
list_for_each_entry(iter, &sbi->s_mb_largest_free_orders[i],
bb_largest_free_order_node) {
if (sbi->s_mb_stats)
atomic64_inc(&sbi->s_bal_cX_groups_considered[CR_POWER2_ALIGNED]);
if (likely(ext4_mb_good_group(ac, iter->bb_group, CR_POWER2_ALIGNED))) {
grp = iter;
break;
}
}
read_unlock(&sbi->s_mb_largest_free_orders_locks[i]);
if (grp)
break;
}
if (!grp) {
/* Increment cr and search again */
*new_cr = CR_GOAL_LEN_FAST;
} else {
*group = grp->bb_group;
ac->ac_flags |= EXT4_MB_CR_POWER2_ALIGNED_OPTIMIZED;
}
}
/*
* Find a suitable group of given order from the average fragments list.
*/
static struct ext4_group_info *
ext4_mb_find_good_group_avg_frag_lists(struct ext4_allocation_context *ac, int order)
{
struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
struct list_head *frag_list = &sbi->s_mb_avg_fragment_size[order];
rwlock_t *frag_list_lock = &sbi->s_mb_avg_fragment_size_locks[order];
struct ext4_group_info *grp = NULL, *iter;
enum criteria cr = ac->ac_criteria;
if (list_empty(frag_list))
return NULL;
read_lock(frag_list_lock);
if (list_empty(frag_list)) {
read_unlock(frag_list_lock);
return NULL;
}
list_for_each_entry(iter, frag_list, bb_avg_fragment_size_node) {
if (sbi->s_mb_stats)
atomic64_inc(&sbi->s_bal_cX_groups_considered[cr]);
if (likely(ext4_mb_good_group(ac, iter->bb_group, cr))) {
grp = iter;
break;
}
}
read_unlock(frag_list_lock);
return grp;
}
/*
* Choose next group by traversing average fragment size list of suitable
* order. Updates *new_cr if cr level needs an update.
*/
static void ext4_mb_choose_next_group_goal_fast(struct ext4_allocation_context *ac,
enum criteria *new_cr, ext4_group_t *group, ext4_group_t ngroups)
{
struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
struct ext4_group_info *grp = NULL;
int i;
if (unlikely(ac->ac_flags & EXT4_MB_CR_GOAL_LEN_FAST_OPTIMIZED)) {
if (sbi->s_mb_stats)
atomic_inc(&sbi->s_bal_goal_fast_bad_suggestions);
}
for (i = mb_avg_fragment_size_order(ac->ac_sb, ac->ac_g_ex.fe_len);
i < MB_NUM_ORDERS(ac->ac_sb); i++) {
grp = ext4_mb_find_good_group_avg_frag_lists(ac, i);
if (grp)
break;
}
if (grp) {
*group = grp->bb_group;
ac->ac_flags |= EXT4_MB_CR_GOAL_LEN_FAST_OPTIMIZED;
} else {
*new_cr = CR_BEST_AVAIL_LEN;
}
}
/*
* We couldn't find a group in CR_GOAL_LEN_FAST so try to find the highest free fragment
* order we have and proactively trim the goal request length to that order to
* find a suitable group faster.
*
* This optimizes allocation speed at the cost of slightly reduced
* preallocations. However, we make sure that we don't trim the request too
* much and fall to CR_GOAL_LEN_SLOW in that case.
*/
static void ext4_mb_choose_next_group_best_avail(struct ext4_allocation_context *ac,
enum criteria *new_cr, ext4_group_t *group, ext4_group_t ngroups)
{
struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
struct ext4_group_info *grp = NULL;
int i, order, min_order;
unsigned long num_stripe_clusters = 0;
if (unlikely(ac->ac_flags & EXT4_MB_CR_BEST_AVAIL_LEN_OPTIMIZED)) {
if (sbi->s_mb_stats)
atomic_inc(&sbi->s_bal_best_avail_bad_suggestions);
}
/*
* mb_avg_fragment_size_order() returns order in a way that makes
* retrieving back the length using (1 << order) inaccurate. Hence, use
* fls() instead since we need to know the actual length while modifying
* goal length.
*/
order = fls(ac->ac_g_ex.fe_len);
min_order = order - sbi->s_mb_best_avail_max_trim_order;
if (min_order < 0)
min_order = 0;
if (1 << min_order < ac->ac_o_ex.fe_len)
min_order = fls(ac->ac_o_ex.fe_len) + 1;
if (sbi->s_stripe > 0) {
/*
* We are assuming that stripe size is always a multiple of
* cluster ratio otherwise __ext4_fill_super exists early.
*/
num_stripe_clusters = EXT4_NUM_B2C(sbi, sbi->s_stripe);
if (1 << min_order < num_stripe_clusters)
min_order = fls(num_stripe_clusters);
}
for (i = order; i >= min_order; i--) {
int frag_order;
/*
* Scale down goal len to make sure we find something
* in the free fragments list. Basically, reduce
* preallocations.
*/
ac->ac_g_ex.fe_len = 1 << i;
if (num_stripe_clusters > 0) {
/*
* Try to round up the adjusted goal length to
* stripe size (in cluster units) multiple for
* efficiency.
*/
ac->ac_g_ex.fe_len = roundup(ac->ac_g_ex.fe_len,
num_stripe_clusters);
}
frag_order = mb_avg_fragment_size_order(ac->ac_sb,
ac->ac_g_ex.fe_len);
grp = ext4_mb_find_good_group_avg_frag_lists(ac, frag_order);
if (grp)
break;
}
if (grp) {
*group = grp->bb_group;
ac->ac_flags |= EXT4_MB_CR_BEST_AVAIL_LEN_OPTIMIZED;
} else {
/* Reset goal length to original goal length before falling into CR_GOAL_LEN_SLOW */
ac->ac_g_ex.fe_len = ac->ac_orig_goal_len;
*new_cr = CR_GOAL_LEN_SLOW;
}
}
static inline int should_optimize_scan(struct ext4_allocation_context *ac)
{
if (unlikely(!test_opt2(ac->ac_sb, MB_OPTIMIZE_SCAN)))
return 0;
if (ac->ac_criteria >= CR_GOAL_LEN_SLOW)
return 0;
if (!ext4_test_inode_flag(ac->ac_inode, EXT4_INODE_EXTENTS))
return 0;
return 1;
}
/*
* Return next linear group for allocation. If linear traversal should not be
* performed, this function just returns the same group
*/
static int
next_linear_group(struct ext4_allocation_context *ac, int group, int ngroups)
{
if (!should_optimize_scan(ac))
goto inc_and_return;
if (ac->ac_groups_linear_remaining) {
ac->ac_groups_linear_remaining--;
goto inc_and_return;
}
return group;
inc_and_return:
/*
* Artificially restricted ngroups for non-extent
* files makes group > ngroups possible on first loop.
*/
return group + 1 >= ngroups ? 0 : group + 1;
}
/*
* ext4_mb_choose_next_group: choose next group for allocation.
*
* @ac Allocation Context
* @new_cr This is an output parameter. If the there is no good group
* available at current CR level, this field is updated to indicate
* the new cr level that should be used.
* @group This is an input / output parameter. As an input it indicates the
* next group that the allocator intends to use for allocation. As
* output, this field indicates the next group that should be used as
* determined by the optimization functions.
* @ngroups Total number of groups
*/
static void ext4_mb_choose_next_group(struct ext4_allocation_context *ac,
enum criteria *new_cr, ext4_group_t *group, ext4_group_t ngroups)
{
*new_cr = ac->ac_criteria;
if (!should_optimize_scan(ac) || ac->ac_groups_linear_remaining) {
*group = next_linear_group(ac, *group, ngroups);
return;
}
if (*new_cr == CR_POWER2_ALIGNED) {
ext4_mb_choose_next_group_p2_aligned(ac, new_cr, group, ngroups);
} else if (*new_cr == CR_GOAL_LEN_FAST) {
ext4_mb_choose_next_group_goal_fast(ac, new_cr, group, ngroups);
} else if (*new_cr == CR_BEST_AVAIL_LEN) {
ext4_mb_choose_next_group_best_avail(ac, new_cr, group, ngroups);
} else {
/*
* TODO: For CR=2, we can arrange groups in an rb tree sorted by
* bb_free. But until that happens, we should never come here.
*/
WARN_ON(1);
}
}
/*
* Cache the order of the largest free extent we have available in this block
* group.
*/
static void
mb_set_largest_free_order(struct super_block *sb, struct ext4_group_info *grp)
{
struct ext4_sb_info *sbi = EXT4_SB(sb);
int i;
for (i = MB_NUM_ORDERS(sb) - 1; i >= 0; i--)
if (grp->bb_counters[i] > 0)
break;
/* No need to move between order lists? */
if (!test_opt2(sb, MB_OPTIMIZE_SCAN) ||
i == grp->bb_largest_free_order) {
grp->bb_largest_free_order = i;
return;
}
if (grp->bb_largest_free_order >= 0) {
write_lock(&sbi->s_mb_largest_free_orders_locks[
grp->bb_largest_free_order]);
list_del_init(&grp->bb_largest_free_order_node);
write_unlock(&sbi->s_mb_largest_free_orders_locks[
grp->bb_largest_free_order]);
}
grp->bb_largest_free_order = i;
if (grp->bb_largest_free_order >= 0 && grp->bb_free) {
write_lock(&sbi->s_mb_largest_free_orders_locks[
grp->bb_largest_free_order]);
list_add_tail(&grp->bb_largest_free_order_node,
&sbi->s_mb_largest_free_orders[grp->bb_largest_free_order]);
write_unlock(&sbi->s_mb_largest_free_orders_locks[
grp->bb_largest_free_order]);
}
}
static noinline_for_stack
void ext4_mb_generate_buddy(struct super_block *sb,
void *buddy, void *bitmap, ext4_group_t group,
struct ext4_group_info *grp)
{
struct ext4_sb_info *sbi = EXT4_SB(sb);
ext4_grpblk_t max = EXT4_CLUSTERS_PER_GROUP(sb);
ext4_grpblk_t i = 0;
ext4_grpblk_t first;
ext4_grpblk_t len;
unsigned free = 0;
unsigned fragments = 0;
unsigned long long period = get_cycles();
/* initialize buddy from bitmap which is aggregation
* of on-disk bitmap and preallocations */
i = mb_find_next_zero_bit(bitmap, max, 0);
grp->bb_first_free = i;
while (i < max) {
fragments++;
first = i;
i = mb_find_next_bit(bitmap, max, i);
len = i - first;
free += len;
if (len > 1)
ext4_mb_mark_free_simple(sb, buddy, first, len, grp);
else
grp->bb_counters[0]++;
if (i < max)
i = mb_find_next_zero_bit(bitmap, max, i);
}
grp->bb_fragments = fragments;
if (free != grp->bb_free) {
ext4_grp_locked_error(sb, group, 0, 0,
"block bitmap and bg descriptor "
"inconsistent: %u vs %u free clusters",
free, grp->bb_free);
/*
* If we intend to continue, we consider group descriptor
* corrupt and update bb_free using bitmap value
*/
grp->bb_free = free;
ext4_mark_group_bitmap_corrupted(sb, group,
EXT4_GROUP_INFO_BBITMAP_CORRUPT);
}
mb_set_largest_free_order(sb, grp);
mb_update_avg_fragment_size(sb, grp);
clear_bit(EXT4_GROUP_INFO_NEED_INIT_BIT, &(grp->bb_state));
period = get_cycles() - period;
atomic_inc(&sbi->s_mb_buddies_generated);
atomic64_add(period, &sbi->s_mb_generation_time);
}
/* The buddy information is attached the buddy cache inode
* for convenience. The information regarding each group
* is loaded via ext4_mb_load_buddy. The information involve
* block bitmap and buddy information. The information are
* stored in the inode as
*
* { page }
* [ group 0 bitmap][ group 0 buddy] [group 1][ group 1]...
*
*
* one block each for bitmap and buddy information.
* So for each group we take up 2 blocks. A page can
* contain blocks_per_page (PAGE_SIZE / blocksize) blocks.
* So it can have information regarding groups_per_page which
* is blocks_per_page/2
*
* Locking note: This routine takes the block group lock of all groups
* for this page; do not hold this lock when calling this routine!
*/
static int ext4_mb_init_cache(struct page *page, char *incore, gfp_t gfp)
{
ext4_group_t ngroups;
int blocksize;
int blocks_per_page;
int groups_per_page;
int err = 0;
int i;
ext4_group_t first_group, group;
int first_block;
struct super_block *sb;
struct buffer_head *bhs;
struct buffer_head **bh = NULL;
struct inode *inode;
char *data;
char *bitmap;
struct ext4_group_info *grinfo;
inode = page->mapping->host;
sb = inode->i_sb;
ngroups = ext4_get_groups_count(sb);
blocksize = i_blocksize(inode);
blocks_per_page = PAGE_SIZE / blocksize;
mb_debug(sb, "init page %lu\n", page->index);
groups_per_page = blocks_per_page >> 1;
if (groups_per_page == 0)
groups_per_page = 1;
/* allocate buffer_heads to read bitmaps */
if (groups_per_page > 1) {
i = sizeof(struct buffer_head *) * groups_per_page;
bh = kzalloc(i, gfp);
if (bh == NULL)
return -ENOMEM;
} else
bh = &bhs;
first_group = page->index * blocks_per_page / 2;
/* read all groups the page covers into the cache */
for (i = 0, group = first_group; i < groups_per_page; i++, group++) {
if (group >= ngroups)
break;
grinfo = ext4_get_group_info(sb, group);
if (!grinfo)
continue;
/*
* If page is uptodate then we came here after online resize
* which added some new uninitialized group info structs, so
* we must skip all initialized uptodate buddies on the page,
* which may be currently in use by an allocating task.
*/
if (PageUptodate(page) && !EXT4_MB_GRP_NEED_INIT(grinfo)) {
bh[i] = NULL;
continue;
}
bh[i] = ext4_read_block_bitmap_nowait(sb, group, false);
if (IS_ERR(bh[i])) {
err = PTR_ERR(bh[i]);
bh[i] = NULL;
goto out;
}
mb_debug(sb, "read bitmap for group %u\n", group);
}
/* wait for I/O completion */
for (i = 0, group = first_group; i < groups_per_page; i++, group++) {
int err2;
if (!bh[i])
continue;
err2 = ext4_wait_block_bitmap(sb, group, bh[i]);
if (!err)
err = err2;
}
first_block = page->index * blocks_per_page;
for (i = 0; i < blocks_per_page; i++) {
group = (first_block + i) >> 1;
if (group >= ngroups)
break;
if (!bh[group - first_group])
/* skip initialized uptodate buddy */
continue;
if (!buffer_verified(bh[group - first_group]))
/* Skip faulty bitmaps */
continue;
err = 0;
/*
* data carry information regarding this
* particular group in the format specified
* above
*
*/
data = page_address(page) + (i * blocksize);
bitmap = bh[group - first_group]->b_data;
/*
* We place the buddy block and bitmap block
* close together
*/
if ((first_block + i) & 1) {
/* this is block of buddy */
BUG_ON(incore == NULL);
mb_debug(sb, "put buddy for group %u in page %lu/%x\n",
group, page->index, i * blocksize);
trace_ext4_mb_buddy_bitmap_load(sb, group);
grinfo = ext4_get_group_info(sb, group);
if (!grinfo) {
err = -EFSCORRUPTED;
goto out;
}
grinfo->bb_fragments = 0;
memset(grinfo->bb_counters, 0,
sizeof(*grinfo->bb_counters) *
(MB_NUM_ORDERS(sb)));
/*
* incore got set to the group block bitmap below
*/
ext4_lock_group(sb, group);
/* init the buddy */
memset(data, 0xff, blocksize);
ext4_mb_generate_buddy(sb, data, incore, group, grinfo);
ext4_unlock_group(sb, group);
incore = NULL;
} else {
/* this is block of bitmap */
BUG_ON(incore != NULL);
mb_debug(sb, "put bitmap for group %u in page %lu/%x\n",
group, page->index, i * blocksize);
trace_ext4_mb_bitmap_load(sb, group);
/* see comments in ext4_mb_put_pa() */
ext4_lock_group(sb, group);
memcpy(data, bitmap, blocksize);
/* mark all preallocated blks used in in-core bitmap */
ext4_mb_generate_from_pa(sb, data, group);
ext4_mb_generate_from_freelist(sb, data, group);
ext4_unlock_group(sb, group);
/* set incore so that the buddy information can be
* generated using this
*/
incore = data;
}
}
SetPageUptodate(page);
out:
if (bh) {
for (i = 0; i < groups_per_page; i++)
brelse(bh[i]);
if (bh != &bhs)
kfree(bh);
}
return err;
}
/*
* Lock the buddy and bitmap pages. This make sure other parallel init_group
* on the same buddy page doesn't happen whild holding the buddy page lock.
* Return locked buddy and bitmap pages on e4b struct. If buddy and bitmap
* are on the same page e4b->bd_buddy_page is NULL and return value is 0.
*/
static int ext4_mb_get_buddy_page_lock(struct super_block *sb,
ext4_group_t group, struct ext4_buddy *e4b, gfp_t gfp)
{
struct inode *inode = EXT4_SB(sb)->s_buddy_cache;
int block, pnum, poff;
int blocks_per_page;
struct page *page;
e4b->bd_buddy_page = NULL;
e4b->bd_bitmap_page = NULL;
blocks_per_page = PAGE_SIZE / sb->s_blocksize;
/*
* the buddy cache inode stores the block bitmap
* and buddy information in consecutive blocks.
* So for each group we need two blocks.
*/
block = group * 2;
pnum = block / blocks_per_page;
poff = block % blocks_per_page;
page = find_or_create_page(inode->i_mapping, pnum, gfp);
if (!page)
return -ENOMEM;
BUG_ON(page->mapping != inode->i_mapping);
e4b->bd_bitmap_page = page;
e4b->bd_bitmap = page_address(page) + (poff * sb->s_blocksize);
if (blocks_per_page >= 2) {
/* buddy and bitmap are on the same page */
return 0;
}
block++;
pnum = block / blocks_per_page;
page = find_or_create_page(inode->i_mapping, pnum, gfp);
if (!page)
return -ENOMEM;
BUG_ON(page->mapping != inode->i_mapping);
e4b->bd_buddy_page = page;
return 0;
}
static void ext4_mb_put_buddy_page_lock(struct ext4_buddy *e4b)
{
if (e4b->bd_bitmap_page) {
unlock_page(e4b->bd_bitmap_page);
put_page(e4b->bd_bitmap_page);
}
if (e4b->bd_buddy_page) {
unlock_page(e4b->bd_buddy_page);
put_page(e4b->bd_buddy_page);
}
}
/*
* Locking note: This routine calls ext4_mb_init_cache(), which takes the
* block group lock of all groups for this page; do not hold the BG lock when
* calling this routine!
*/
static noinline_for_stack
int ext4_mb_init_group(struct super_block *sb, ext4_group_t group, gfp_t gfp)
{
struct ext4_group_info *this_grp;
struct ext4_buddy e4b;
struct page *page;
int ret = 0;
might_sleep();
mb_debug(sb, "init group %u\n", group);
this_grp = ext4_get_group_info(sb, group);
if (!this_grp)
return -EFSCORRUPTED;
/*
* This ensures that we don't reinit the buddy cache
* page which map to the group from which we are already
* allocating. If we are looking at the buddy cache we would
* have taken a reference using ext4_mb_load_buddy and that
* would have pinned buddy page to page cache.
* The call to ext4_mb_get_buddy_page_lock will mark the
* page accessed.
*/
ret = ext4_mb_get_buddy_page_lock(sb, group, &e4b, gfp);
if (ret || !EXT4_MB_GRP_NEED_INIT(this_grp)) {
/*
* somebody initialized the group
* return without doing anything
*/
goto err;
}
page = e4b.bd_bitmap_page;
ret = ext4_mb_init_cache(page, NULL, gfp);
if (ret)
goto err;
if (!PageUptodate(page)) {
ret = -EIO;
goto err;
}
if (e4b.bd_buddy_page == NULL) {
/*
* If both the bitmap and buddy are in
* the same page we don't need to force
* init the buddy
*/
ret = 0;
goto err;
}
/* init buddy cache */
page = e4b.bd_buddy_page;
ret = ext4_mb_init_cache(page, e4b.bd_bitmap, gfp);
if (ret)
goto err;
if (!PageUptodate(page)) {
ret = -EIO;
goto err;
}
err:
ext4_mb_put_buddy_page_lock(&e4b);
return ret;
}
/*
* Locking note: This routine calls ext4_mb_init_cache(), which takes the
* block group lock of all groups for this page; do not hold the BG lock when
* calling this routine!
*/
static noinline_for_stack int
ext4_mb_load_buddy_gfp(struct super_block *sb, ext4_group_t group,
struct ext4_buddy *e4b, gfp_t gfp)
{
int blocks_per_page;
int block;
int pnum;
int poff;
struct page *page;
int ret;
struct ext4_group_info *grp;
struct ext4_sb_info *sbi = EXT4_SB(sb);
struct inode *inode = sbi->s_buddy_cache;
might_sleep();
mb_debug(sb, "load group %u\n", group);
blocks_per_page = PAGE_SIZE / sb->s_blocksize;
grp = ext4_get_group_info(sb, group);
if (!grp)
return -EFSCORRUPTED;
e4b->bd_blkbits = sb->s_blocksize_bits;
e4b->bd_info = grp;
e4b->bd_sb = sb;
e4b->bd_group = group;
e4b->bd_buddy_page = NULL;
e4b->bd_bitmap_page = NULL;
if (unlikely(EXT4_MB_GRP_NEED_INIT(grp))) {
/*
* we need full data about the group
* to make a good selection
*/
ret = ext4_mb_init_group(sb, group, gfp);
if (ret)
return ret;
}
/*
* the buddy cache inode stores the block bitmap
* and buddy information in consecutive blocks.
* So for each group we need two blocks.
*/
block = group * 2;
pnum = block / blocks_per_page;
poff = block % blocks_per_page;
/* we could use find_or_create_page(), but it locks page
* what we'd like to avoid in fast path ... */
page = find_get_page_flags(inode->i_mapping, pnum, FGP_ACCESSED);
if (page == NULL || !PageUptodate(page)) {
if (page)
/*
* drop the page reference and try
* to get the page with lock. If we
* are not uptodate that implies
* somebody just created the page but
* is yet to initialize the same. So
* wait for it to initialize.
*/
put_page(page);
page = find_or_create_page(inode->i_mapping, pnum, gfp);
if (page) {
if (WARN_RATELIMIT(page->mapping != inode->i_mapping,
"ext4: bitmap's paging->mapping != inode->i_mapping\n")) {
/* should never happen */
unlock_page(page);
ret = -EINVAL;
goto err;
}
if (!PageUptodate(page)) {
ret = ext4_mb_init_cache(page, NULL, gfp);
if (ret) {
unlock_page(page);
goto err;
}
mb_cmp_bitmaps(e4b, page_address(page) +
(poff * sb->s_blocksize));
}
unlock_page(page);
}
}
if (page == NULL) {
ret = -ENOMEM;
goto err;
}
if (!PageUptodate(page)) {
ret = -EIO;
goto err;
}
/* Pages marked accessed already */
e4b->bd_bitmap_page = page;
e4b->bd_bitmap = page_address(page) + (poff * sb->s_blocksize);
block++;
pnum = block / blocks_per_page;
poff = block % blocks_per_page;
page = find_get_page_flags(inode->i_mapping, pnum, FGP_ACCESSED);
if (page == NULL || !PageUptodate(page)) {
if (page)
put_page(page);
page = find_or_create_page(inode->i_mapping, pnum, gfp);
if (page) {
if (WARN_RATELIMIT(page->mapping != inode->i_mapping,
"ext4: buddy bitmap's page->mapping != inode->i_mapping\n")) {
/* should never happen */
unlock_page(page);
ret = -EINVAL;
goto err;
}
if (!PageUptodate(page)) {
ret = ext4_mb_init_cache(page, e4b->bd_bitmap,
gfp);
if (ret) {
unlock_page(page);
goto err;
}
}
unlock_page(page);
}
}
if (page == NULL) {
ret = -ENOMEM;
goto err;
}
if (!PageUptodate(page)) {
ret = -EIO;
goto err;
}
/* Pages marked accessed already */
e4b->bd_buddy_page = page;
e4b->bd_buddy = page_address(page) + (poff * sb->s_blocksize);
return 0;
err:
if (page)
put_page(page);
if (e4b->bd_bitmap_page)
put_page(e4b->bd_bitmap_page);
e4b->bd_buddy = NULL;
e4b->bd_bitmap = NULL;
return ret;
}
static int ext4_mb_load_buddy(struct super_block *sb, ext4_group_t group,
struct ext4_buddy *e4b)
{
return ext4_mb_load_buddy_gfp(sb, group, e4b, GFP_NOFS);
}
static void ext4_mb_unload_buddy(struct ext4_buddy *e4b)
{
if (e4b->bd_bitmap_page)
put_page(e4b->bd_bitmap_page);
if (e4b->bd_buddy_page)
put_page(e4b->bd_buddy_page);
}
static int mb_find_order_for_block(struct ext4_buddy *e4b, int block)
{
int order = 1, max;
void *bb;
BUG_ON(e4b->bd_bitmap == e4b->bd_buddy);
BUG_ON(block >= (1 << (e4b->bd_blkbits + 3)));
while (order <= e4b->bd_blkbits + 1) {
bb = mb_find_buddy(e4b, order, &max);
if (!mb_test_bit(block >> order, bb)) {
/* this block is part of buddy of order 'order' */
return order;
}
order++;
}
return 0;
}
static void mb_clear_bits(void *bm, int cur, int len)
{
__u32 *addr;
len = cur + len;
while (cur < len) {
if ((cur & 31) == 0 && (len - cur) >= 32) {
/* fast path: clear whole word at once */
addr = bm + (cur >> 3);
*addr = 0;
cur += 32;
continue;
}
mb_clear_bit(cur, bm);
cur++;
}
}
/* clear bits in given range
* will return first found zero bit if any, -1 otherwise
*/
static int mb_test_and_clear_bits(void *bm, int cur, int len)
{
__u32 *addr;
int zero_bit = -1;
len = cur + len;
while (cur < len) {
if ((cur & 31) == 0 && (len - cur) >= 32) {
/* fast path: clear whole word at once */
addr = bm + (cur >> 3);
if (*addr != (__u32)(-1) && zero_bit == -1)
zero_bit = cur + mb_find_next_zero_bit(addr, 32, 0);
*addr = 0;
cur += 32;
continue;
}
if (!mb_test_and_clear_bit(cur, bm) && zero_bit == -1)
zero_bit = cur;
cur++;
}
return zero_bit;
}
void mb_set_bits(void *bm, int cur, int len)
{
__u32 *addr;
len = cur + len;
while (cur < len) {
if ((cur & 31) == 0 && (len - cur) >= 32) {
/* fast path: set whole word at once */
addr = bm + (cur >> 3);
*addr = 0xffffffff;
cur += 32;
continue;
}
mb_set_bit(cur, bm);
cur++;
}
}
static inline int mb_buddy_adjust_border(int* bit, void* bitmap, int side)
{
if (mb_test_bit(*bit + side, bitmap)) {
mb_clear_bit(*bit, bitmap);
(*bit) -= side;
return 1;
}
else {
(*bit) += side;
mb_set_bit(*bit, bitmap);
return -1;
}
}
static void mb_buddy_mark_free(struct ext4_buddy *e4b, int first, int last)
{
int max;
int order = 1;
void *buddy = mb_find_buddy(e4b, order, &max);
while (buddy) {
void *buddy2;
/* Bits in range [first; last] are known to be set since
* corresponding blocks were allocated. Bits in range
* (first; last) will stay set because they form buddies on
* upper layer. We just deal with borders if they don't
* align with upper layer and then go up.
* Releasing entire group is all about clearing
* single bit of highest order buddy.
*/
/* Example:
* ---------------------------------
* | 1 | 1 | 1 | 1 |
* ---------------------------------
* | 0 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
* ---------------------------------
* 0 1 2 3 4 5 6 7
* \_____________________/
*
* Neither [1] nor [6] is aligned to above layer.
* Left neighbour [0] is free, so mark it busy,
* decrease bb_counters and extend range to
* [0; 6]
* Right neighbour [7] is busy. It can't be coaleasced with [6], so
* mark [6] free, increase bb_counters and shrink range to
* [0; 5].
* Then shift range to [0; 2], go up and do the same.
*/
if (first & 1)
e4b->bd_info->bb_counters[order] += mb_buddy_adjust_border(&first, buddy, -1);
if (!(last & 1))
e4b->bd_info->bb_counters[order] += mb_buddy_adjust_border(&last, buddy, 1);
if (first > last)
break;
order++;
buddy2 = mb_find_buddy(e4b, order, &max);
if (!buddy2) {
mb_clear_bits(buddy, first, last - first + 1);
e4b->bd_info->bb_counters[order - 1] += last - first + 1;
break;
}
first >>= 1;
last >>= 1;
buddy = buddy2;
}
}
static void mb_free_blocks(struct inode *inode, struct ext4_buddy *e4b,
int first, int count)
{
int left_is_free = 0;
int right_is_free = 0;
int block;
int last = first + count - 1;
struct super_block *sb = e4b->bd_sb;
if (WARN_ON(count == 0))
return;
BUG_ON(last >= (sb->s_blocksize << 3));
assert_spin_locked(ext4_group_lock_ptr(sb, e4b->bd_group));
/* Don't bother if the block group is corrupt. */
if (unlikely(EXT4_MB_GRP_BBITMAP_CORRUPT(e4b->bd_info)))
return;
mb_check_buddy(e4b);
mb_free_blocks_double(inode, e4b, first, count);
this_cpu_inc(discard_pa_seq);
e4b->bd_info->bb_free += count;
if (first < e4b->bd_info->bb_first_free)
e4b->bd_info->bb_first_free = first;
/* access memory sequentially: check left neighbour,
* clear range and then check right neighbour
*/
if (first != 0)
left_is_free = !mb_test_bit(first - 1, e4b->bd_bitmap);
block = mb_test_and_clear_bits(e4b->bd_bitmap, first, count);
if (last + 1 < EXT4_SB(sb)->s_mb_maxs[0])
right_is_free = !mb_test_bit(last + 1, e4b->bd_bitmap);
if (unlikely(block != -1)) {
struct ext4_sb_info *sbi = EXT4_SB(sb);
ext4_fsblk_t blocknr;
blocknr = ext4_group_first_block_no(sb, e4b->bd_group);
blocknr += EXT4_C2B(sbi, block);
if (!(sbi->s_mount_state & EXT4_FC_REPLAY)) {
ext4_grp_locked_error(sb, e4b->bd_group,
inode ? inode->i_ino : 0,
blocknr,
"freeing already freed block (bit %u); block bitmap corrupt.",
block);
ext4_mark_group_bitmap_corrupted(
sb, e4b->bd_group,
EXT4_GROUP_INFO_BBITMAP_CORRUPT);
}
goto done;
}
/* let's maintain fragments counter */
if (left_is_free && right_is_free)
e4b->bd_info->bb_fragments--;
else if (!left_is_free && !right_is_free)
e4b->bd_info->bb_fragments++;
/* buddy[0] == bd_bitmap is a special case, so handle
* it right away and let mb_buddy_mark_free stay free of
* zero order checks.
* Check if neighbours are to be coaleasced,
* adjust bitmap bb_counters and borders appropriately.
*/
if (first & 1) {
first += !left_is_free;
e4b->bd_info->bb_counters[0] += left_is_free ? -1 : 1;
}
if (!(last & 1)) {
last -= !right_is_free;
e4b->bd_info->bb_counters[0] += right_is_free ? -1 : 1;
}
if (first <= last)
mb_buddy_mark_free(e4b, first >> 1, last >> 1);
done:
mb_set_largest_free_order(sb, e4b->bd_info);
mb_update_avg_fragment_size(sb, e4b->bd_info);
mb_check_buddy(e4b);
}
static int mb_find_extent(struct ext4_buddy *e4b, int block,
int needed, struct ext4_free_extent *ex)
{
int next = block;
int max, order;
void *buddy;
assert_spin_locked(ext4_group_lock_ptr(e4b->bd_sb, e4b->bd_group));
BUG_ON(ex == NULL);
buddy = mb_find_buddy(e4b, 0, &max);
BUG_ON(buddy == NULL);
BUG_ON(block >= max);
if (mb_test_bit(block, buddy)) {
ex->fe_len = 0;
ex->fe_start = 0;
ex->fe_group = 0;
return 0;
}
/* find actual order */
order = mb_find_order_for_block(e4b, block);
block = block >> order;
ex->fe_len = 1 << order;
ex->fe_start = block << order;
ex->fe_group = e4b->bd_group;
/* calc difference from given start */
next = next - ex->fe_start;
ex->fe_len -= next;
ex->fe_start += next;
while (needed > ex->fe_len &&
mb_find_buddy(e4b, order, &max)) {
if (block + 1 >= max)
break;
next = (block + 1) * (1 << order);
if (mb_test_bit(next, e4b->bd_bitmap))
break;
order = mb_find_order_for_block(e4b, next);
block = next >> order;
ex->fe_len += 1 << order;
}
if (ex->fe_start + ex->fe_len > EXT4_CLUSTERS_PER_GROUP(e4b->bd_sb)) {
/* Should never happen! (but apparently sometimes does?!?) */
WARN_ON(1);
ext4_grp_locked_error(e4b->bd_sb, e4b->bd_group, 0, 0,
"corruption or bug in mb_find_extent "
"block=%d, order=%d needed=%d ex=%u/%d/%d@%u",
block, order, needed, ex->fe_group, ex->fe_start,
ex->fe_len, ex->fe_logical);
ex->fe_len = 0;
ex->fe_start = 0;
ex->fe_group = 0;
}
return ex->fe_len;
}
static int mb_mark_used(struct ext4_buddy *e4b, struct ext4_free_extent *ex)
{
int ord;
int mlen = 0;
int max = 0;
int cur;
int start = ex->fe_start;
int len = ex->fe_len;
unsigned ret = 0;
int len0 = len;
void *buddy;
bool split = false;
BUG_ON(start + len > (e4b->bd_sb->s_blocksize << 3));
BUG_ON(e4b->bd_group != ex->fe_group);
assert_spin_locked(ext4_group_lock_ptr(e4b->bd_sb, e4b->bd_group));
mb_check_buddy(e4b);
mb_mark_used_double(e4b, start, len);
this_cpu_inc(discard_pa_seq);
e4b->bd_info->bb_free -= len;
if (e4b->bd_info->bb_first_free == start)
e4b->bd_info->bb_first_free += len;
/* let's maintain fragments counter */
if (start != 0)
mlen = !mb_test_bit(start - 1, e4b->bd_bitmap);
if (start + len < EXT4_SB(e4b->bd_sb)->s_mb_maxs[0])
max = !mb_test_bit(start + len, e4b->bd_bitmap);
if (mlen && max)
e4b->bd_info->bb_fragments++;
else if (!mlen && !max)
e4b->bd_info->bb_fragments--;
/* let's maintain buddy itself */
while (len) {
if (!split)
ord = mb_find_order_for_block(e4b, start);
if (((start >> ord) << ord) == start && len >= (1 << ord)) {
/* the whole chunk may be allocated at once! */
mlen = 1 << ord;
if (!split)
buddy = mb_find_buddy(e4b, ord, &max);
else
split = false;
BUG_ON((start >> ord) >= max);
mb_set_bit(start >> ord, buddy);
e4b->bd_info->bb_counters[ord]--;
start += mlen;
len -= mlen;
BUG_ON(len < 0);
continue;
}
/* store for history */
if (ret == 0)
ret = len | (ord << 16);
/* we have to split large buddy */
BUG_ON(ord <= 0);
buddy = mb_find_buddy(e4b, ord, &max);
mb_set_bit(start >> ord, buddy);
e4b->bd_info->bb_counters[ord]--;
ord--;
cur = (start >> ord) & ~1U;
buddy = mb_find_buddy(e4b, ord, &max);
mb_clear_bit(cur, buddy);
mb_clear_bit(cur + 1, buddy);
e4b->bd_info->bb_counters[ord]++;
e4b->bd_info->bb_counters[ord]++;
split = true;
}
mb_set_largest_free_order(e4b->bd_sb, e4b->bd_info);
mb_update_avg_fragment_size(e4b->bd_sb, e4b->bd_info);
mb_set_bits(e4b->bd_bitmap, ex->fe_start, len0);
mb_check_buddy(e4b);
return ret;
}
/*
* Must be called under group lock!
*/
static void ext4_mb_use_best_found(struct ext4_allocation_context *ac,
struct ext4_buddy *e4b)
{
struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
int ret;
BUG_ON(ac->ac_b_ex.fe_group != e4b->bd_group);
BUG_ON(ac->ac_status == AC_STATUS_FOUND);
ac->ac_b_ex.fe_len = min(ac->ac_b_ex.fe_len, ac->ac_g_ex.fe_len);
ac->ac_b_ex.fe_logical = ac->ac_g_ex.fe_logical;
ret = mb_mark_used(e4b, &ac->ac_b_ex);
/* preallocation can change ac_b_ex, thus we store actually
* allocated blocks for history */
ac->ac_f_ex = ac->ac_b_ex;
ac->ac_status = AC_STATUS_FOUND;
ac->ac_tail = ret & 0xffff;
ac->ac_buddy = ret >> 16;
/*
* take the page reference. We want the page to be pinned
* so that we don't get a ext4_mb_init_cache_call for this
* group until we update the bitmap. That would mean we
* double allocate blocks. The reference is dropped
* in ext4_mb_release_context
*/
ac->ac_bitmap_page = e4b->bd_bitmap_page;
get_page(ac->ac_bitmap_page);
ac->ac_buddy_page = e4b->bd_buddy_page;
get_page(ac->ac_buddy_page);
/* store last allocated for subsequent stream allocation */
if (ac->ac_flags & EXT4_MB_STREAM_ALLOC) {
spin_lock(&sbi->s_md_lock);
sbi->s_mb_last_group = ac->ac_f_ex.fe_group;
sbi->s_mb_last_start = ac->ac_f_ex.fe_start;
spin_unlock(&sbi->s_md_lock);
}
/*
* As we've just preallocated more space than
* user requested originally, we store allocated
* space in a special descriptor.
*/
if (ac->ac_o_ex.fe_len < ac->ac_b_ex.fe_len)
ext4_mb_new_preallocation(ac);
}
static void ext4_mb_check_limits(struct ext4_allocation_context *ac,
struct ext4_buddy *e4b,
int finish_group)
{
struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
struct ext4_free_extent *bex = &ac->ac_b_ex;
struct ext4_free_extent *gex = &ac->ac_g_ex;
if (ac->ac_status == AC_STATUS_FOUND)
return;
/*
* We don't want to scan for a whole year
*/
if (ac->ac_found > sbi->s_mb_max_to_scan &&
!(ac->ac_flags & EXT4_MB_HINT_FIRST)) {
ac->ac_status = AC_STATUS_BREAK;
return;
}
/*
* Haven't found good chunk so far, let's continue
*/
if (bex->fe_len < gex->fe_len)
return;
if (finish_group || ac->ac_found > sbi->s_mb_min_to_scan)
ext4_mb_use_best_found(ac, e4b);
}
/*
* The routine checks whether found extent is good enough. If it is,
* then the extent gets marked used and flag is set to the context
* to stop scanning. Otherwise, the extent is compared with the
* previous found extent and if new one is better, then it's stored
* in the context. Later, the best found extent will be used, if
* mballoc can't find good enough extent.
*
* The algorithm used is roughly as follows:
*
* * If free extent found is exactly as big as goal, then
* stop the scan and use it immediately
*
* * If free extent found is smaller than goal, then keep retrying
* upto a max of sbi->s_mb_max_to_scan times (default 200). After
* that stop scanning and use whatever we have.
*
* * If free extent found is bigger than goal, then keep retrying
* upto a max of sbi->s_mb_min_to_scan times (default 10) before
* stopping the scan and using the extent.
*
*
* FIXME: real allocation policy is to be designed yet!
*/
static void ext4_mb_measure_extent(struct ext4_allocation_context *ac,
struct ext4_free_extent *ex,
struct ext4_buddy *e4b)
{
struct ext4_free_extent *bex = &ac->ac_b_ex;
struct ext4_free_extent *gex = &ac->ac_g_ex;
BUG_ON(ex->fe_len <= 0);
BUG_ON(ex->fe_len > EXT4_CLUSTERS_PER_GROUP(ac->ac_sb));
BUG_ON(ex->fe_start >= EXT4_CLUSTERS_PER_GROUP(ac->ac_sb));
BUG_ON(ac->ac_status != AC_STATUS_CONTINUE);
ac->ac_found++;
ac->ac_cX_found[ac->ac_criteria]++;
/*
* The special case - take what you catch first
*/
if (unlikely(ac->ac_flags & EXT4_MB_HINT_FIRST)) {
*bex = *ex;
ext4_mb_use_best_found(ac, e4b);
return;
}
/*
* Let's check whether the chuck is good enough
*/
if (ex->fe_len == gex->fe_len) {
*bex = *ex;
ext4_mb_use_best_found(ac, e4b);
return;
}
/*
* If this is first found extent, just store it in the context
*/
if (bex->fe_len == 0) {
*bex = *ex;
return;
}
/*
* If new found extent is better, store it in the context
*/
if (bex->fe_len < gex->fe_len) {
/* if the request isn't satisfied, any found extent
* larger than previous best one is better */
if (ex->fe_len > bex->fe_len)
*bex = *ex;
} else if (ex->fe_len > gex->fe_len) {
/* if the request is satisfied, then we try to find
* an extent that still satisfy the request, but is
* smaller than previous one */
if (ex->fe_len < bex->fe_len)
*bex = *ex;
}
ext4_mb_check_limits(ac, e4b, 0);
}
static noinline_for_stack
void ext4_mb_try_best_found(struct ext4_allocation_context *ac,
struct ext4_buddy *e4b)
{
struct ext4_free_extent ex = ac->ac_b_ex;
ext4_group_t group = ex.fe_group;
int max;
int err;
BUG_ON(ex.fe_len <= 0);
err = ext4_mb_load_buddy(ac->ac_sb, group, e4b);
if (err)
return;
ext4_lock_group(ac->ac_sb, group);
max = mb_find_extent(e4b, ex.fe_start, ex.fe_len, &ex);
if (max > 0) {
ac->ac_b_ex = ex;
ext4_mb_use_best_found(ac, e4b);
}
ext4_unlock_group(ac->ac_sb, group);
ext4_mb_unload_buddy(e4b);
}
static noinline_for_stack
int ext4_mb_find_by_goal(struct ext4_allocation_context *ac,
struct ext4_buddy *e4b)
{
ext4_group_t group = ac->ac_g_ex.fe_group;
int max;
int err;
struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
struct ext4_group_info *grp = ext4_get_group_info(ac->ac_sb, group);
struct ext4_free_extent ex;
if (!grp)
return -EFSCORRUPTED;
if (!(ac->ac_flags & (EXT4_MB_HINT_TRY_GOAL | EXT4_MB_HINT_GOAL_ONLY)))
return 0;
if (grp->bb_free == 0)
return 0;
err = ext4_mb_load_buddy(ac->ac_sb, group, e4b);
if (err)
return err;
if (unlikely(EXT4_MB_GRP_BBITMAP_CORRUPT(e4b->bd_info))) {
ext4_mb_unload_buddy(e4b);
return 0;
}
ext4_lock_group(ac->ac_sb, group);
max = mb_find_extent(e4b, ac->ac_g_ex.fe_start,
ac->ac_g_ex.fe_len, &ex);
ex.fe_logical = 0xDEADFA11; /* debug value */
if (max >= ac->ac_g_ex.fe_len &&
ac->ac_g_ex.fe_len == EXT4_B2C(sbi, sbi->s_stripe)) {
ext4_fsblk_t start;
start = ext4_grp_offs_to_block(ac->ac_sb, &ex);
/* use do_div to get remainder (would be 64-bit modulo) */
if (do_div(start, sbi->s_stripe) == 0) {
ac->ac_found++;
ac->ac_b_ex = ex;
ext4_mb_use_best_found(ac, e4b);
}
} else if (max >= ac->ac_g_ex.fe_len) {
BUG_ON(ex.fe_len <= 0);
BUG_ON(ex.fe_group != ac->ac_g_ex.fe_group);
BUG_ON(ex.fe_start != ac->ac_g_ex.fe_start);
ac->ac_found++;
ac->ac_b_ex = ex;
ext4_mb_use_best_found(ac, e4b);
} else if (max > 0 && (ac->ac_flags & EXT4_MB_HINT_MERGE)) {
/* Sometimes, caller may want to merge even small
* number of blocks to an existing extent */
BUG_ON(ex.fe_len <= 0);
BUG_ON(ex.fe_group != ac->ac_g_ex.fe_group);
BUG_ON(ex.fe_start != ac->ac_g_ex.fe_start);
ac->ac_found++;
ac->ac_b_ex = ex;
ext4_mb_use_best_found(ac, e4b);
}
ext4_unlock_group(ac->ac_sb, group);
ext4_mb_unload_buddy(e4b);
return 0;
}
/*
* The routine scans buddy structures (not bitmap!) from given order
* to max order and tries to find big enough chunk to satisfy the req
*/
static noinline_for_stack
void ext4_mb_simple_scan_group(struct ext4_allocation_context *ac,
struct ext4_buddy *e4b)
{
struct super_block *sb = ac->ac_sb;
struct ext4_group_info *grp = e4b->bd_info;
void *buddy;
int i;
int k;
int max;
BUG_ON(ac->ac_2order <= 0);
for (i = ac->ac_2order; i < MB_NUM_ORDERS(sb); i++) {
if (grp->bb_counters[i] == 0)
continue;
buddy = mb_find_buddy(e4b, i, &max);
if (WARN_RATELIMIT(buddy == NULL,
"ext4: mb_simple_scan_group: mb_find_buddy failed, (%d)\n", i))
continue;
k = mb_find_next_zero_bit(buddy, max, 0);
if (k >= max) {
ext4_grp_locked_error(ac->ac_sb, e4b->bd_group, 0, 0,
"%d free clusters of order %d. But found 0",
grp->bb_counters[i], i);
ext4_mark_group_bitmap_corrupted(ac->ac_sb,
e4b->bd_group,
EXT4_GROUP_INFO_BBITMAP_CORRUPT);
break;
}
ac->ac_found++;
ac->ac_cX_found[ac->ac_criteria]++;
ac->ac_b_ex.fe_len = 1 << i;
ac->ac_b_ex.fe_start = k << i;
ac->ac_b_ex.fe_group = e4b->bd_group;
ext4_mb_use_best_found(ac, e4b);
BUG_ON(ac->ac_f_ex.fe_len != ac->ac_g_ex.fe_len);
if (EXT4_SB(sb)->s_mb_stats)
atomic_inc(&EXT4_SB(sb)->s_bal_2orders);
break;
}
}
/*
* The routine scans the group and measures all found extents.
* In order to optimize scanning, caller must pass number of
* free blocks in the group, so the routine can know upper limit.
*/
static noinline_for_stack
void ext4_mb_complex_scan_group(struct ext4_allocation_context *ac,
struct ext4_buddy *e4b)
{
struct super_block *sb = ac->ac_sb;
void *bitmap = e4b->bd_bitmap;
struct ext4_free_extent ex;
int i, j, freelen;
int free;
free = e4b->bd_info->bb_free;
if (WARN_ON(free <= 0))
return;
i = e4b->bd_info->bb_first_free;
while (free && ac->ac_status == AC_STATUS_CONTINUE) {
i = mb_find_next_zero_bit(bitmap,
EXT4_CLUSTERS_PER_GROUP(sb), i);
if (i >= EXT4_CLUSTERS_PER_GROUP(sb)) {
/*
* IF we have corrupt bitmap, we won't find any
* free blocks even though group info says we
* have free blocks
*/
ext4_grp_locked_error(sb, e4b->bd_group, 0, 0,
"%d free clusters as per "
"group info. But bitmap says 0",
free);
ext4_mark_group_bitmap_corrupted(sb, e4b->bd_group,
EXT4_GROUP_INFO_BBITMAP_CORRUPT);
break;
}
if (ac->ac_criteria < CR_FAST) {
/*
* In CR_GOAL_LEN_FAST and CR_BEST_AVAIL_LEN, we are
* sure that this group will have a large enough
* continuous free extent, so skip over the smaller free
* extents
*/
j = mb_find_next_bit(bitmap,
EXT4_CLUSTERS_PER_GROUP(sb), i);
freelen = j - i;
if (freelen < ac->ac_g_ex.fe_len) {
i = j;
free -= freelen;
continue;
}
}
mb_find_extent(e4b, i, ac->ac_g_ex.fe_len, &ex);
if (WARN_ON(ex.fe_len <= 0))
break;
if (free < ex.fe_len) {
ext4_grp_locked_error(sb, e4b->bd_group, 0, 0,
"%d free clusters as per "
"group info. But got %d blocks",
free, ex.fe_len);
ext4_mark_group_bitmap_corrupted(sb, e4b->bd_group,
EXT4_GROUP_INFO_BBITMAP_CORRUPT);
/*
* The number of free blocks differs. This mostly
* indicate that the bitmap is corrupt. So exit
* without claiming the space.
*/
break;
}
ex.fe_logical = 0xDEADC0DE; /* debug value */
ext4_mb_measure_extent(ac, &ex, e4b);
i += ex.fe_len;
free -= ex.fe_len;
}
ext4_mb_check_limits(ac, e4b, 1);
}
/*
* This is a special case for storages like raid5
* we try to find stripe-aligned chunks for stripe-size-multiple requests
*/
static noinline_for_stack
void ext4_mb_scan_aligned(struct ext4_allocation_context *ac,
struct ext4_buddy *e4b)
{
struct super_block *sb = ac->ac_sb;
struct ext4_sb_info *sbi = EXT4_SB(sb);
void *bitmap = e4b->bd_bitmap;
struct ext4_free_extent ex;
ext4_fsblk_t first_group_block;
ext4_fsblk_t a;
ext4_grpblk_t i, stripe;
int max;
BUG_ON(sbi->s_stripe == 0);
/* find first stripe-aligned block in group */
first_group_block = ext4_group_first_block_no(sb, e4b->bd_group);
a = first_group_block + sbi->s_stripe - 1;
do_div(a, sbi->s_stripe);
i = (a * sbi->s_stripe) - first_group_block;
stripe = EXT4_B2C(sbi, sbi->s_stripe);
i = EXT4_B2C(sbi, i);
while (i < EXT4_CLUSTERS_PER_GROUP(sb)) {
if (!mb_test_bit(i, bitmap)) {
max = mb_find_extent(e4b, i, stripe, &ex);
if (max >= stripe) {
ac->ac_found++;
ac->ac_cX_found[ac->ac_criteria]++;
ex.fe_logical = 0xDEADF00D; /* debug value */
ac->ac_b_ex = ex;
ext4_mb_use_best_found(ac, e4b);
break;
}
}
i += stripe;
}
}
/*
* This is also called BEFORE we load the buddy bitmap.
* Returns either 1 or 0 indicating that the group is either suitable
* for the allocation or not.
*/
static bool ext4_mb_good_group(struct ext4_allocation_context *ac,
ext4_group_t group, enum criteria cr)
{
ext4_grpblk_t free, fragments;
int flex_size = ext4_flex_bg_size(EXT4_SB(ac->ac_sb));
struct ext4_group_info *grp = ext4_get_group_info(ac->ac_sb, group);
BUG_ON(cr < CR_POWER2_ALIGNED || cr >= EXT4_MB_NUM_CRS);
if (unlikely(EXT4_MB_GRP_BBITMAP_CORRUPT(grp) || !grp))
return false;
free = grp->bb_free;
if (free == 0)
return false;
fragments = grp->bb_fragments;
if (fragments == 0)
return false;
switch (cr) {
case CR_POWER2_ALIGNED:
BUG_ON(ac->ac_2order == 0);
/* Avoid using the first bg of a flexgroup for data files */
if ((ac->ac_flags & EXT4_MB_HINT_DATA) &&
(flex_size >= EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME) &&
((group % flex_size) == 0))
return false;
if (free < ac->ac_g_ex.fe_len)
return false;
if (ac->ac_2order >= MB_NUM_ORDERS(ac->ac_sb))
return true;
if (grp->bb_largest_free_order < ac->ac_2order)
return false;
return true;
case CR_GOAL_LEN_FAST:
case CR_BEST_AVAIL_LEN:
if ((free / fragments) >= ac->ac_g_ex.fe_len)
return true;
break;
case CR_GOAL_LEN_SLOW:
if (free >= ac->ac_g_ex.fe_len)
return true;
break;
case CR_ANY_FREE:
return true;
default:
BUG();
}
return false;
}
/*
* This could return negative error code if something goes wrong
* during ext4_mb_init_group(). This should not be called with
* ext4_lock_group() held.
*
* Note: because we are conditionally operating with the group lock in
* the EXT4_MB_STRICT_CHECK case, we need to fake out sparse in this
* function using __acquire and __release. This means we need to be
* super careful before messing with the error path handling via "goto
* out"!
*/
static int ext4_mb_good_group_nolock(struct ext4_allocation_context *ac,
ext4_group_t group, enum criteria cr)
{
struct ext4_group_info *grp = ext4_get_group_info(ac->ac_sb, group);
struct super_block *sb = ac->ac_sb;
struct ext4_sb_info *sbi = EXT4_SB(sb);
bool should_lock = ac->ac_flags & EXT4_MB_STRICT_CHECK;
ext4_grpblk_t free;
int ret = 0;
if (!grp)
return -EFSCORRUPTED;
if (sbi->s_mb_stats)
atomic64_inc(&sbi->s_bal_cX_groups_considered[ac->ac_criteria]);
if (should_lock) {
ext4_lock_group(sb, group);
__release(ext4_group_lock_ptr(sb, group));
}
free = grp->bb_free;
if (free == 0)
goto out;
if (cr <= CR_FAST && free < ac->ac_g_ex.fe_len)
goto out;
if (unlikely(EXT4_MB_GRP_BBITMAP_CORRUPT(grp)))
goto out;
if (should_lock) {
__acquire(ext4_group_lock_ptr(sb, group));
ext4_unlock_group(sb, group);
}
/* We only do this if the grp has never been initialized */
if (unlikely(EXT4_MB_GRP_NEED_INIT(grp))) {
struct ext4_group_desc *gdp =
ext4_get_group_desc(sb, group, NULL);
int ret;
/*
* cr=CR_POWER2_ALIGNED/CR_GOAL_LEN_FAST is a very optimistic
* search to find large good chunks almost for free. If buddy
* data is not ready, then this optimization makes no sense. But
* we never skip the first block group in a flex_bg, since this
* gets used for metadata block allocation, and we want to make
* sure we locate metadata blocks in the first block group in
* the flex_bg if possible.
*/
if (cr < CR_FAST &&
(!sbi->s_log_groups_per_flex ||
((group & ((1 << sbi->s_log_groups_per_flex) - 1)) != 0)) &&
!(ext4_has_group_desc_csum(sb) &&
(gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT))))
return 0;
ret = ext4_mb_init_group(sb, group, GFP_NOFS);
if (ret)
return ret;
}
if (should_lock) {
ext4_lock_group(sb, group);
__release(ext4_group_lock_ptr(sb, group));
}
ret = ext4_mb_good_group(ac, group, cr);
out:
if (should_lock) {
__acquire(ext4_group_lock_ptr(sb, group));
ext4_unlock_group(sb, group);
}
return ret;
}
/*
* Start prefetching @nr block bitmaps starting at @group.
* Return the next group which needs to be prefetched.
*/
ext4_group_t ext4_mb_prefetch(struct super_block *sb, ext4_group_t group,
unsigned int nr, int *cnt)
{
ext4_group_t ngroups = ext4_get_groups_count(sb);
struct buffer_head *bh;
struct blk_plug plug;
blk_start_plug(&plug);
while (nr-- > 0) {
struct ext4_group_desc *gdp = ext4_get_group_desc(sb, group,
NULL);
struct ext4_group_info *grp = ext4_get_group_info(sb, group);
/*
* Prefetch block groups with free blocks; but don't
* bother if it is marked uninitialized on disk, since
* it won't require I/O to read. Also only try to
* prefetch once, so we avoid getblk() call, which can
* be expensive.
*/
if (gdp && grp && !EXT4_MB_GRP_TEST_AND_SET_READ(grp) &&
EXT4_MB_GRP_NEED_INIT(grp) &&
ext4_free_group_clusters(sb, gdp) > 0 ) {
bh = ext4_read_block_bitmap_nowait(sb, group, true);
if (bh && !IS_ERR(bh)) {
if (!buffer_uptodate(bh) && cnt)
(*cnt)++;
brelse(bh);
}
}
if (++group >= ngroups)
group = 0;
}
blk_finish_plug(&plug);
return group;
}
/*
* Prefetching reads the block bitmap into the buffer cache; but we
* need to make sure that the buddy bitmap in the page cache has been
* initialized. Note that ext4_mb_init_group() will block if the I/O
* is not yet completed, or indeed if it was not initiated by
* ext4_mb_prefetch did not start the I/O.
*
* TODO: We should actually kick off the buddy bitmap setup in a work
* queue when the buffer I/O is completed, so that we don't block
* waiting for the block allocation bitmap read to finish when
* ext4_mb_prefetch_fini is called from ext4_mb_regular_allocator().
*/
void ext4_mb_prefetch_fini(struct super_block *sb, ext4_group_t group,
unsigned int nr)
{
struct ext4_group_desc *gdp;
struct ext4_group_info *grp;
while (nr-- > 0) {
if (!group)
group = ext4_get_groups_count(sb);
group--;
gdp = ext4_get_group_desc(sb, group, NULL);
grp = ext4_get_group_info(sb, group);
if (grp && gdp && EXT4_MB_GRP_NEED_INIT(grp) &&
ext4_free_group_clusters(sb, gdp) > 0) {
if (ext4_mb_init_group(sb, group, GFP_NOFS))
break;
}
}
}
static noinline_for_stack int
ext4_mb_regular_allocator(struct ext4_allocation_context *ac)
{
ext4_group_t prefetch_grp = 0, ngroups, group, i;
enum criteria new_cr, cr = CR_GOAL_LEN_FAST;
int err = 0, first_err = 0;
unsigned int nr = 0, prefetch_ios = 0;
struct ext4_sb_info *sbi;
struct super_block *sb;
struct ext4_buddy e4b;
int lost;
sb = ac->ac_sb;
sbi = EXT4_SB(sb);
ngroups = ext4_get_groups_count(sb);
/* non-extent files are limited to low blocks/groups */
if (!(ext4_test_inode_flag(ac->ac_inode, EXT4_INODE_EXTENTS)))
ngroups = sbi->s_blockfile_groups;
BUG_ON(ac->ac_status == AC_STATUS_FOUND);
/* first, try the goal */
err = ext4_mb_find_by_goal(ac, &e4b);
if (err || ac->ac_status == AC_STATUS_FOUND)
goto out;
if (unlikely(ac->ac_flags & EXT4_MB_HINT_GOAL_ONLY))
goto out;
/*
* ac->ac_2order is set only if the fe_len is a power of 2
* if ac->ac_2order is set we also set criteria to 0 so that we
* try exact allocation using buddy.
*/
i = fls(ac->ac_g_ex.fe_len);
ac->ac_2order = 0;
/*
* We search using buddy data only if the order of the request
* is greater than equal to the sbi_s_mb_order2_reqs
* You can tune it via /sys/fs/ext4/<partition>/mb_order2_req
* We also support searching for power-of-two requests only for
* requests upto maximum buddy size we have constructed.
*/
if (i >= sbi->s_mb_order2_reqs && i <= MB_NUM_ORDERS(sb)) {
/*
* This should tell if fe_len is exactly power of 2
*/
if ((ac->ac_g_ex.fe_len & (~(1 << (i - 1)))) == 0)
ac->ac_2order = array_index_nospec(i - 1,
MB_NUM_ORDERS(sb));
}
/* if stream allocation is enabled, use global goal */
if (ac->ac_flags & EXT4_MB_STREAM_ALLOC) {
/* TBD: may be hot point */
spin_lock(&sbi->s_md_lock);
ac->ac_g_ex.fe_group = sbi->s_mb_last_group;
ac->ac_g_ex.fe_start = sbi->s_mb_last_start;
spin_unlock(&sbi->s_md_lock);
}
/*
* Let's just scan groups to find more-less suitable blocks We
* start with CR_GOAL_LEN_FAST, unless it is power of 2
* aligned, in which case let's do that faster approach first.
*/
if (ac->ac_2order)
cr = CR_POWER2_ALIGNED;
repeat:
for (; cr < EXT4_MB_NUM_CRS && ac->ac_status == AC_STATUS_CONTINUE; cr++) {
ac->ac_criteria = cr;
/*
* searching for the right group start
* from the goal value specified
*/
group = ac->ac_g_ex.fe_group;
ac->ac_groups_linear_remaining = sbi->s_mb_max_linear_groups;
prefetch_grp = group;
for (i = 0, new_cr = cr; i < ngroups; i++,
ext4_mb_choose_next_group(ac, &new_cr, &group, ngroups)) {
int ret = 0;
cond_resched();
if (new_cr != cr) {
cr = new_cr;
goto repeat;
}
/*
* Batch reads of the block allocation bitmaps
* to get multiple READs in flight; limit
* prefetching at cr=0/1, otherwise mballoc can
* spend a lot of time loading imperfect groups
*/
if ((prefetch_grp == group) &&
(cr >= CR_FAST ||
prefetch_ios < sbi->s_mb_prefetch_limit)) {
nr = sbi->s_mb_prefetch;
if (ext4_has_feature_flex_bg(sb)) {
nr = 1 << sbi->s_log_groups_per_flex;
nr -= group & (nr - 1);
nr = min(nr, sbi->s_mb_prefetch);
}
prefetch_grp = ext4_mb_prefetch(sb, group,
nr, &prefetch_ios);
}
/* This now checks without needing the buddy page */
ret = ext4_mb_good_group_nolock(ac, group, cr);
if (ret <= 0) {
if (!first_err)
first_err = ret;
continue;
}
err = ext4_mb_load_buddy(sb, group, &e4b);
if (err)
goto out;
ext4_lock_group(sb, group);
/*
* We need to check again after locking the
* block group
*/
ret = ext4_mb_good_group(ac, group, cr);
if (ret == 0) {
ext4_unlock_group(sb, group);
ext4_mb_unload_buddy(&e4b);
continue;
}
ac->ac_groups_scanned++;
if (cr == CR_POWER2_ALIGNED)
ext4_mb_simple_scan_group(ac, &e4b);
else if ((cr == CR_GOAL_LEN_FAST ||
cr == CR_BEST_AVAIL_LEN) &&
sbi->s_stripe &&
!(ac->ac_g_ex.fe_len %
EXT4_B2C(sbi, sbi->s_stripe)))
ext4_mb_scan_aligned(ac, &e4b);
else
ext4_mb_complex_scan_group(ac, &e4b);
ext4_unlock_group(sb, group);
ext4_mb_unload_buddy(&e4b);
if (ac->ac_status != AC_STATUS_CONTINUE)
break;
}
/* Processed all groups and haven't found blocks */
if (sbi->s_mb_stats && i == ngroups)
atomic64_inc(&sbi->s_bal_cX_failed[cr]);
if (i == ngroups && ac->ac_criteria == CR_BEST_AVAIL_LEN)
/* Reset goal length to original goal length before
* falling into CR_GOAL_LEN_SLOW */
ac->ac_g_ex.fe_len = ac->ac_orig_goal_len;
}
if (ac->ac_b_ex.fe_len > 0 && ac->ac_status != AC_STATUS_FOUND &&
!(ac->ac_flags & EXT4_MB_HINT_FIRST)) {
/*
* We've been searching too long. Let's try to allocate
* the best chunk we've found so far
*/
ext4_mb_try_best_found(ac, &e4b);
if (ac->ac_status != AC_STATUS_FOUND) {
/*
* Someone more lucky has already allocated it.
* The only thing we can do is just take first
* found block(s)
*/
lost = atomic_inc_return(&sbi->s_mb_lost_chunks);
mb_debug(sb, "lost chunk, group: %u, start: %d, len: %d, lost: %d\n",
ac->ac_b_ex.fe_group, ac->ac_b_ex.fe_start,
ac->ac_b_ex.fe_len, lost);
ac->ac_b_ex.fe_group = 0;
ac->ac_b_ex.fe_start = 0;
ac->ac_b_ex.fe_len = 0;
ac->ac_status = AC_STATUS_CONTINUE;
ac->ac_flags |= EXT4_MB_HINT_FIRST;
cr = CR_ANY_FREE;
goto repeat;
}
}
if (sbi->s_mb_stats && ac->ac_status == AC_STATUS_FOUND)
atomic64_inc(&sbi->s_bal_cX_hits[ac->ac_criteria]);
out:
if (!err && ac->ac_status != AC_STATUS_FOUND && first_err)
err = first_err;
mb_debug(sb, "Best len %d, origin len %d, ac_status %u, ac_flags 0x%x, cr %d ret %d\n",
ac->ac_b_ex.fe_len, ac->ac_o_ex.fe_len, ac->ac_status,
ac->ac_flags, cr, err);
if (nr)
ext4_mb_prefetch_fini(sb, prefetch_grp, nr);
return err;
}
static void *ext4_mb_seq_groups_start(struct seq_file *seq, loff_t *pos)
{
struct super_block *sb = pde_data(file_inode(seq->file));
ext4_group_t group;
if (*pos < 0 || *pos >= ext4_get_groups_count(sb))
return NULL;
group = *pos + 1;
return (void *) ((unsigned long) group);
}
static void *ext4_mb_seq_groups_next(struct seq_file *seq, void *v, loff_t *pos)
{
struct super_block *sb = pde_data(file_inode(seq->file));
ext4_group_t group;
++*pos;
if (*pos < 0 || *pos >= ext4_get_groups_count(sb))
return NULL;
group = *pos + 1;
return (void *) ((unsigned long) group);
}
static int ext4_mb_seq_groups_show(struct seq_file *seq, void *v)
{
struct super_block *sb = pde_data(file_inode(seq->file));
ext4_group_t group = (ext4_group_t) ((unsigned long) v);
int i;
int err, buddy_loaded = 0;
struct ext4_buddy e4b;
struct ext4_group_info *grinfo;
unsigned char blocksize_bits = min_t(unsigned char,
sb->s_blocksize_bits,
EXT4_MAX_BLOCK_LOG_SIZE);
struct sg {
struct ext4_group_info info;
ext4_grpblk_t counters[EXT4_MAX_BLOCK_LOG_SIZE + 2];
} sg;
group--;
if (group == 0)
seq_puts(seq, "#group: free frags first ["
" 2^0 2^1 2^2 2^3 2^4 2^5 2^6 "
" 2^7 2^8 2^9 2^10 2^11 2^12 2^13 ]\n");
i = (blocksize_bits + 2) * sizeof(sg.info.bb_counters[0]) +
sizeof(struct ext4_group_info);
grinfo = ext4_get_group_info(sb, group);
if (!grinfo)
return 0;
/* Load the group info in memory only if not already loaded. */
if (unlikely(EXT4_MB_GRP_NEED_INIT(grinfo))) {
err = ext4_mb_load_buddy(sb, group, &e4b);
if (err) {
seq_printf(seq, "#%-5u: I/O error\n", group);
return 0;
}
buddy_loaded = 1;
}
memcpy(&sg, grinfo, i);
if (buddy_loaded)
ext4_mb_unload_buddy(&e4b);
seq_printf(seq, "#%-5u: %-5u %-5u %-5u [", group, sg.info.bb_free,
sg.info.bb_fragments, sg.info.bb_first_free);
for (i = 0; i <= 13; i++)
seq_printf(seq, " %-5u", i <= blocksize_bits + 1 ?
sg.info.bb_counters[i] : 0);
seq_puts(seq, " ]\n");
return 0;
}
static void ext4_mb_seq_groups_stop(struct seq_file *seq, void *v)
{
}
const struct seq_operations ext4_mb_seq_groups_ops = {
.start = ext4_mb_seq_groups_start,
.next = ext4_mb_seq_groups_next,
.stop = ext4_mb_seq_groups_stop,
.show = ext4_mb_seq_groups_show,
};
int ext4_seq_mb_stats_show(struct seq_file *seq, void *offset)
{
struct super_block *sb = seq->private;
struct ext4_sb_info *sbi = EXT4_SB(sb);
seq_puts(seq, "mballoc:\n");
if (!sbi->s_mb_stats) {
seq_puts(seq, "\tmb stats collection turned off.\n");
seq_puts(
seq,
"\tTo enable, please write \"1\" to sysfs file mb_stats.\n");
return 0;
}
seq_printf(seq, "\treqs: %u\n", atomic_read(&sbi->s_bal_reqs));
seq_printf(seq, "\tsuccess: %u\n", atomic_read(&sbi->s_bal_success));
seq_printf(seq, "\tgroups_scanned: %u\n",
atomic_read(&sbi->s_bal_groups_scanned));
/* CR_POWER2_ALIGNED stats */
seq_puts(seq, "\tcr_p2_aligned_stats:\n");
seq_printf(seq, "\t\thits: %llu\n",
atomic64_read(&sbi->s_bal_cX_hits[CR_POWER2_ALIGNED]));
seq_printf(
seq, "\t\tgroups_considered: %llu\n",
atomic64_read(
&sbi->s_bal_cX_groups_considered[CR_POWER2_ALIGNED]));
seq_printf(seq, "\t\textents_scanned: %u\n",
atomic_read(&sbi->s_bal_cX_ex_scanned[CR_POWER2_ALIGNED]));
seq_printf(seq, "\t\tuseless_loops: %llu\n",
atomic64_read(&sbi->s_bal_cX_failed[CR_POWER2_ALIGNED]));
seq_printf(seq, "\t\tbad_suggestions: %u\n",
atomic_read(&sbi->s_bal_p2_aligned_bad_suggestions));
/* CR_GOAL_LEN_FAST stats */
seq_puts(seq, "\tcr_goal_fast_stats:\n");
seq_printf(seq, "\t\thits: %llu\n",
atomic64_read(&sbi->s_bal_cX_hits[CR_GOAL_LEN_FAST]));
seq_printf(seq, "\t\tgroups_considered: %llu\n",
atomic64_read(
&sbi->s_bal_cX_groups_considered[CR_GOAL_LEN_FAST]));
seq_printf(seq, "\t\textents_scanned: %u\n",
atomic_read(&sbi->s_bal_cX_ex_scanned[CR_GOAL_LEN_FAST]));
seq_printf(seq, "\t\tuseless_loops: %llu\n",
atomic64_read(&sbi->s_bal_cX_failed[CR_GOAL_LEN_FAST]));
seq_printf(seq, "\t\tbad_suggestions: %u\n",
atomic_read(&sbi->s_bal_goal_fast_bad_suggestions));
/* CR_BEST_AVAIL_LEN stats */
seq_puts(seq, "\tcr_best_avail_stats:\n");
seq_printf(seq, "\t\thits: %llu\n",
atomic64_read(&sbi->s_bal_cX_hits[CR_BEST_AVAIL_LEN]));
seq_printf(
seq, "\t\tgroups_considered: %llu\n",
atomic64_read(
&sbi->s_bal_cX_groups_considered[CR_BEST_AVAIL_LEN]));
seq_printf(seq, "\t\textents_scanned: %u\n",
atomic_read(&sbi->s_bal_cX_ex_scanned[CR_BEST_AVAIL_LEN]));
seq_printf(seq, "\t\tuseless_loops: %llu\n",
atomic64_read(&sbi->s_bal_cX_failed[CR_BEST_AVAIL_LEN]));
seq_printf(seq, "\t\tbad_suggestions: %u\n",
atomic_read(&sbi->s_bal_best_avail_bad_suggestions));
/* CR_GOAL_LEN_SLOW stats */
seq_puts(seq, "\tcr_goal_slow_stats:\n");
seq_printf(seq, "\t\thits: %llu\n",
atomic64_read(&sbi->s_bal_cX_hits[CR_GOAL_LEN_SLOW]));
seq_printf(seq, "\t\tgroups_considered: %llu\n",
atomic64_read(
&sbi->s_bal_cX_groups_considered[CR_GOAL_LEN_SLOW]));
seq_printf(seq, "\t\textents_scanned: %u\n",
atomic_read(&sbi->s_bal_cX_ex_scanned[CR_GOAL_LEN_SLOW]));
seq_printf(seq, "\t\tuseless_loops: %llu\n",
atomic64_read(&sbi->s_bal_cX_failed[CR_GOAL_LEN_SLOW]));
/* CR_ANY_FREE stats */
seq_puts(seq, "\tcr_any_free_stats:\n");
seq_printf(seq, "\t\thits: %llu\n",
atomic64_read(&sbi->s_bal_cX_hits[CR_ANY_FREE]));
seq_printf(
seq, "\t\tgroups_considered: %llu\n",
atomic64_read(&sbi->s_bal_cX_groups_considered[CR_ANY_FREE]));
seq_printf(seq, "\t\textents_scanned: %u\n",
atomic_read(&sbi->s_bal_cX_ex_scanned[CR_ANY_FREE]));
seq_printf(seq, "\t\tuseless_loops: %llu\n",
atomic64_read(&sbi->s_bal_cX_failed[CR_ANY_FREE]));
/* Aggregates */
seq_printf(seq, "\textents_scanned: %u\n",
atomic_read(&sbi->s_bal_ex_scanned));
seq_printf(seq, "\t\tgoal_hits: %u\n", atomic_read(&sbi->s_bal_goals));
seq_printf(seq, "\t\tlen_goal_hits: %u\n",
atomic_read(&sbi->s_bal_len_goals));
seq_printf(seq, "\t\t2^n_hits: %u\n", atomic_read(&sbi->s_bal_2orders));
seq_printf(seq, "\t\tbreaks: %u\n", atomic_read(&sbi->s_bal_breaks));
seq_printf(seq, "\t\tlost: %u\n", atomic_read(&sbi->s_mb_lost_chunks));
seq_printf(seq, "\tbuddies_generated: %u/%u\n",
atomic_read(&sbi->s_mb_buddies_generated),
ext4_get_groups_count(sb));
seq_printf(seq, "\tbuddies_time_used: %llu\n",
atomic64_read(&sbi->s_mb_generation_time));
seq_printf(seq, "\tpreallocated: %u\n",
atomic_read(&sbi->s_mb_preallocated));
seq_printf(seq, "\tdiscarded: %u\n", atomic_read(&sbi->s_mb_discarded));
return 0;
}
static void *ext4_mb_seq_structs_summary_start(struct seq_file *seq, loff_t *pos)
__acquires(&EXT4_SB(sb)->s_mb_rb_lock)
{
struct super_block *sb = pde_data(file_inode(seq->file));
unsigned long position;
if (*pos < 0 || *pos >= 2*MB_NUM_ORDERS(sb))
return NULL;
position = *pos + 1;
return (void *) ((unsigned long) position);
}
static void *ext4_mb_seq_structs_summary_next(struct seq_file *seq, void *v, loff_t *pos)
{
struct super_block *sb = pde_data(file_inode(seq->file));
unsigned long position;
++*pos;
if (*pos < 0 || *pos >= 2*MB_NUM_ORDERS(sb))
return NULL;
position = *pos + 1;
return (void *) ((unsigned long) position);
}
static int ext4_mb_seq_structs_summary_show(struct seq_file *seq, void *v)
{
struct super_block *sb = pde_data(file_inode(seq->file));
struct ext4_sb_info *sbi = EXT4_SB(sb);
unsigned long position = ((unsigned long) v);
struct ext4_group_info *grp;
unsigned int count;
position--;
if (position >= MB_NUM_ORDERS(sb)) {
position -= MB_NUM_ORDERS(sb);
if (position == 0)
seq_puts(seq, "avg_fragment_size_lists:\n");
count = 0;
read_lock(&sbi->s_mb_avg_fragment_size_locks[position]);
list_for_each_entry(grp, &sbi->s_mb_avg_fragment_size[position],
bb_avg_fragment_size_node)
count++;
read_unlock(&sbi->s_mb_avg_fragment_size_locks[position]);
seq_printf(seq, "\tlist_order_%u_groups: %u\n",
(unsigned int)position, count);
return 0;
}
if (position == 0) {
seq_printf(seq, "optimize_scan: %d\n",
test_opt2(sb, MB_OPTIMIZE_SCAN) ? 1 : 0);
seq_puts(seq, "max_free_order_lists:\n");
}
count = 0;
read_lock(&sbi->s_mb_largest_free_orders_locks[position]);
list_for_each_entry(grp, &sbi->s_mb_largest_free_orders[position],
bb_largest_free_order_node)
count++;
read_unlock(&sbi->s_mb_largest_free_orders_locks[position]);
seq_printf(seq, "\tlist_order_%u_groups: %u\n",
(unsigned int)position, count);
return 0;
}
static void ext4_mb_seq_structs_summary_stop(struct seq_file *seq, void *v)
{
}
const struct seq_operations ext4_mb_seq_structs_summary_ops = {
.start = ext4_mb_seq_structs_summary_start,
.next = ext4_mb_seq_structs_summary_next,
.stop = ext4_mb_seq_structs_summary_stop,
.show = ext4_mb_seq_structs_summary_show,
};
static struct kmem_cache *get_groupinfo_cache(int blocksize_bits)
{
int cache_index = blocksize_bits - EXT4_MIN_BLOCK_LOG_SIZE;
struct kmem_cache *cachep = ext4_groupinfo_caches[cache_index];
BUG_ON(!cachep);
return cachep;
}
/*
* Allocate the top-level s_group_info array for the specified number
* of groups
*/
int ext4_mb_alloc_groupinfo(struct super_block *sb, ext4_group_t ngroups)
{
struct ext4_sb_info *sbi = EXT4_SB(sb);
unsigned size;
struct ext4_group_info ***old_groupinfo, ***new_groupinfo;
size = (ngroups + EXT4_DESC_PER_BLOCK(sb) - 1) >>
EXT4_DESC_PER_BLOCK_BITS(sb);
if (size <= sbi->s_group_info_size)
return 0;
size = roundup_pow_of_two(sizeof(*sbi->s_group_info) * size);
new_groupinfo = kvzalloc(size, GFP_KERNEL);
if (!new_groupinfo) {
ext4_msg(sb, KERN_ERR, "can't allocate buddy meta group");
return -ENOMEM;
}
rcu_read_lock();
old_groupinfo = rcu_dereference(sbi->s_group_info);
if (old_groupinfo)
memcpy(new_groupinfo, old_groupinfo,
sbi->s_group_info_size * sizeof(*sbi->s_group_info));
rcu_read_unlock();
rcu_assign_pointer(sbi->s_group_info, new_groupinfo);
sbi->s_group_info_size = size / sizeof(*sbi->s_group_info);
if (old_groupinfo)
ext4_kvfree_array_rcu(old_groupinfo);
ext4_debug("allocated s_groupinfo array for %d meta_bg's\n",
sbi->s_group_info_size);
return 0;
}
/* Create and initialize ext4_group_info data for the given group. */
int ext4_mb_add_groupinfo(struct super_block *sb, ext4_group_t group,
struct ext4_group_desc *desc)
{
int i;
int metalen = 0;
int idx = group >> EXT4_DESC_PER_BLOCK_BITS(sb);
struct ext4_sb_info *sbi = EXT4_SB(sb);
struct ext4_group_info **meta_group_info;
struct kmem_cache *cachep = get_groupinfo_cache(sb->s_blocksize_bits);
/*
* First check if this group is the first of a reserved block.
* If it's true, we have to allocate a new table of pointers
* to ext4_group_info structures
*/
if (group % EXT4_DESC_PER_BLOCK(sb) == 0) {
metalen = sizeof(*meta_group_info) <<
EXT4_DESC_PER_BLOCK_BITS(sb);
meta_group_info = kmalloc(metalen, GFP_NOFS);
if (meta_group_info == NULL) {
ext4_msg(sb, KERN_ERR, "can't allocate mem "
"for a buddy group");
return -ENOMEM;
}
rcu_read_lock();
rcu_dereference(sbi->s_group_info)[idx] = meta_group_info;
rcu_read_unlock();
}
meta_group_info = sbi_array_rcu_deref(sbi, s_group_info, idx);
i = group & (EXT4_DESC_PER_BLOCK(sb) - 1);
meta_group_info[i] = kmem_cache_zalloc(cachep, GFP_NOFS);
if (meta_group_info[i] == NULL) {
ext4_msg(sb, KERN_ERR, "can't allocate buddy mem");
goto exit_group_info;
}
set_bit(EXT4_GROUP_INFO_NEED_INIT_BIT,
&(meta_group_info[i]->bb_state));
/*
* initialize bb_free to be able to skip
* empty groups without initialization
*/
if (ext4_has_group_desc_csum(sb) &&
(desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT))) {
meta_group_info[i]->bb_free =
ext4_free_clusters_after_init(sb, group, desc);
} else {
meta_group_info[i]->bb_free =
ext4_free_group_clusters(sb, desc);
}
INIT_LIST_HEAD(&meta_group_info[i]->bb_prealloc_list);
init_rwsem(&meta_group_info[i]->alloc_sem);
meta_group_info[i]->bb_free_root = RB_ROOT;
INIT_LIST_HEAD(&meta_group_info[i]->bb_largest_free_order_node);
INIT_LIST_HEAD(&meta_group_info[i]->bb_avg_fragment_size_node);
meta_group_info[i]->bb_largest_free_order = -1; /* uninit */
meta_group_info[i]->bb_avg_fragment_size_order = -1; /* uninit */
meta_group_info[i]->bb_group = group;
mb_group_bb_bitmap_alloc(sb, meta_group_info[i], group);
return 0;
exit_group_info:
/* If a meta_group_info table has been allocated, release it now */
if (group % EXT4_DESC_PER_BLOCK(sb) == 0) {
struct ext4_group_info ***group_info;
rcu_read_lock();
group_info = rcu_dereference(sbi->s_group_info);
kfree(group_info[idx]);
group_info[idx] = NULL;
rcu_read_unlock();
}
return -ENOMEM;
} /* ext4_mb_add_groupinfo */
static int ext4_mb_init_backend(struct super_block *sb)
{
ext4_group_t ngroups = ext4_get_groups_count(sb);
ext4_group_t i;
struct ext4_sb_info *sbi = EXT4_SB(sb);
int err;
struct ext4_group_desc *desc;
struct ext4_group_info ***group_info;
struct kmem_cache *cachep;
err = ext4_mb_alloc_groupinfo(sb, ngroups);
if (err)
return err;
sbi->s_buddy_cache = new_inode(sb);
if (sbi->s_buddy_cache == NULL) {
ext4_msg(sb, KERN_ERR, "can't get new inode");
goto err_freesgi;
}
/* To avoid potentially colliding with an valid on-disk inode number,
* use EXT4_BAD_INO for the buddy cache inode number. This inode is
* not in the inode hash, so it should never be found by iget(), but
* this will avoid confusion if it ever shows up during debugging. */
sbi->s_buddy_cache->i_ino = EXT4_BAD_INO;
EXT4_I(sbi->s_buddy_cache)->i_disksize = 0;
for (i = 0; i < ngroups; i++) {
cond_resched();
desc = ext4_get_group_desc(sb, i, NULL);
if (desc == NULL) {
ext4_msg(sb, KERN_ERR, "can't read descriptor %u", i);
goto err_freebuddy;
}
if (ext4_mb_add_groupinfo(sb, i, desc) != 0)
goto err_freebuddy;
}
if (ext4_has_feature_flex_bg(sb)) {
/* a single flex group is supposed to be read by a single IO.
* 2 ^ s_log_groups_per_flex != UINT_MAX as s_mb_prefetch is
* unsigned integer, so the maximum shift is 32.
*/
if (sbi->s_es->s_log_groups_per_flex >= 32) {
ext4_msg(sb, KERN_ERR, "too many log groups per flexible block group");
goto err_freebuddy;
}
sbi->s_mb_prefetch = min_t(uint, 1 << sbi->s_es->s_log_groups_per_flex,
BLK_MAX_SEGMENT_SIZE >> (sb->s_blocksize_bits - 9));
sbi->s_mb_prefetch *= 8; /* 8 prefetch IOs in flight at most */
} else {
sbi->s_mb_prefetch = 32;
}
if (sbi->s_mb_prefetch > ext4_get_groups_count(sb))
sbi->s_mb_prefetch = ext4_get_groups_count(sb);
/* now many real IOs to prefetch within a single allocation at cr=0
* given cr=0 is an CPU-related optimization we shouldn't try to
* load too many groups, at some point we should start to use what
* we've got in memory.
* with an average random access time 5ms, it'd take a second to get
* 200 groups (* N with flex_bg), so let's make this limit 4
*/
sbi->s_mb_prefetch_limit = sbi->s_mb_prefetch * 4;
if (sbi->s_mb_prefetch_limit > ext4_get_groups_count(sb))
sbi->s_mb_prefetch_limit = ext4_get_groups_count(sb);
return 0;
err_freebuddy:
cachep = get_groupinfo_cache(sb->s_blocksize_bits);
while (i-- > 0) {
struct ext4_group_info *grp = ext4_get_group_info(sb, i);
if (grp)
kmem_cache_free(cachep, grp);
}
i = sbi->s_group_info_size;
rcu_read_lock();
group_info = rcu_dereference(sbi->s_group_info);
while (i-- > 0)
kfree(group_info[i]);
rcu_read_unlock();
iput(sbi->s_buddy_cache);
err_freesgi:
rcu_read_lock();
kvfree(rcu_dereference(sbi->s_group_info));
rcu_read_unlock();
return -ENOMEM;
}
static void ext4_groupinfo_destroy_slabs(void)
{
int i;
for (i = 0; i < NR_GRPINFO_CACHES; i++) {
kmem_cache_destroy(ext4_groupinfo_caches[i]);
ext4_groupinfo_caches[i] = NULL;
}
}
static int ext4_groupinfo_create_slab(size_t size)
{
static DEFINE_MUTEX(ext4_grpinfo_slab_create_mutex);
int slab_size;
int blocksize_bits = order_base_2(size);
int cache_index = blocksize_bits - EXT4_MIN_BLOCK_LOG_SIZE;
struct kmem_cache *cachep;
if (cache_index >= NR_GRPINFO_CACHES)
return -EINVAL;
if (unlikely(cache_index < 0))
cache_index = 0;
mutex_lock(&ext4_grpinfo_slab_create_mutex);
if (ext4_groupinfo_caches[cache_index]) {
mutex_unlock(&ext4_grpinfo_slab_create_mutex);
return 0; /* Already created */
}
slab_size = offsetof(struct ext4_group_info,
bb_counters[blocksize_bits + 2]);
cachep = kmem_cache_create(ext4_groupinfo_slab_names[cache_index],
slab_size, 0, SLAB_RECLAIM_ACCOUNT,
NULL);
ext4_groupinfo_caches[cache_index] = cachep;
mutex_unlock(&ext4_grpinfo_slab_create_mutex);
if (!cachep) {
printk(KERN_EMERG
"EXT4-fs: no memory for groupinfo slab cache\n");
return -ENOMEM;
}
return 0;
}
static void ext4_discard_work(struct work_struct *work)
{
struct ext4_sb_info *sbi = container_of(work,
struct ext4_sb_info, s_discard_work);
struct super_block *sb = sbi->s_sb;
struct ext4_free_data *fd, *nfd;
struct ext4_buddy e4b;
struct list_head discard_list;
ext4_group_t grp, load_grp;
int err = 0;
INIT_LIST_HEAD(&discard_list);
spin_lock(&sbi->s_md_lock);
list_splice_init(&sbi->s_discard_list, &discard_list);
spin_unlock(&sbi->s_md_lock);
load_grp = UINT_MAX;
list_for_each_entry_safe(fd, nfd, &discard_list, efd_list) {
/*
* If filesystem is umounting or no memory or suffering
* from no space, give up the discard
*/
if ((sb->s_flags & SB_ACTIVE) && !err &&
!atomic_read(&sbi->s_retry_alloc_pending)) {
grp = fd->efd_group;
if (grp != load_grp) {
if (load_grp != UINT_MAX)
ext4_mb_unload_buddy(&e4b);
err = ext4_mb_load_buddy(sb, grp, &e4b);
if (err) {
kmem_cache_free(ext4_free_data_cachep, fd);
load_grp = UINT_MAX;
continue;
} else {
load_grp = grp;
}
}
ext4_lock_group(sb, grp);
ext4_try_to_trim_range(sb, &e4b, fd->efd_start_cluster,
fd->efd_start_cluster + fd->efd_count - 1, 1);
ext4_unlock_group(sb, grp);
}
kmem_cache_free(ext4_free_data_cachep, fd);
}
if (load_grp != UINT_MAX)
ext4_mb_unload_buddy(&e4b);
}
int ext4_mb_init(struct super_block *sb)
{
struct ext4_sb_info *sbi = EXT4_SB(sb);
unsigned i, j;
unsigned offset, offset_incr;
unsigned max;
int ret;
i = MB_NUM_ORDERS(sb) * sizeof(*sbi->s_mb_offsets);
sbi->s_mb_offsets = kmalloc(i, GFP_KERNEL);
if (sbi->s_mb_offsets == NULL) {
ret = -ENOMEM;
goto out;
}
i = MB_NUM_ORDERS(sb) * sizeof(*sbi->s_mb_maxs);
sbi->s_mb_maxs = kmalloc(i, GFP_KERNEL);
if (sbi->s_mb_maxs == NULL) {
ret = -ENOMEM;
goto out;
}
ret = ext4_groupinfo_create_slab(sb->s_blocksize);
if (ret < 0)
goto out;
/* order 0 is regular bitmap */
sbi->s_mb_maxs[0] = sb->s_blocksize << 3;
sbi->s_mb_offsets[0] = 0;
i = 1;
offset = 0;
offset_incr = 1 << (sb->s_blocksize_bits - 1);
max = sb->s_blocksize << 2;
do {
sbi->s_mb_offsets[i] = offset;
sbi->s_mb_maxs[i] = max;
offset += offset_incr;
offset_incr = offset_incr >> 1;
max = max >> 1;
i++;
} while (i < MB_NUM_ORDERS(sb));
sbi->s_mb_avg_fragment_size =
kmalloc_array(MB_NUM_ORDERS(sb), sizeof(struct list_head),
GFP_KERNEL);
if (!sbi->s_mb_avg_fragment_size) {
ret = -ENOMEM;
goto out;
}
sbi->s_mb_avg_fragment_size_locks =
kmalloc_array(MB_NUM_ORDERS(sb), sizeof(rwlock_t),
GFP_KERNEL);
if (!sbi->s_mb_avg_fragment_size_locks) {
ret = -ENOMEM;
goto out;
}
for (i = 0; i < MB_NUM_ORDERS(sb); i++) {
INIT_LIST_HEAD(&sbi->s_mb_avg_fragment_size[i]);
rwlock_init(&sbi->s_mb_avg_fragment_size_locks[i]);
}
sbi->s_mb_largest_free_orders =
kmalloc_array(MB_NUM_ORDERS(sb), sizeof(struct list_head),
GFP_KERNEL);
if (!sbi->s_mb_largest_free_orders) {
ret = -ENOMEM;
goto out;
}
sbi->s_mb_largest_free_orders_locks =
kmalloc_array(MB_NUM_ORDERS(sb), sizeof(rwlock_t),
GFP_KERNEL);
if (!sbi->s_mb_largest_free_orders_locks) {
ret = -ENOMEM;
goto out;
}
for (i = 0; i < MB_NUM_ORDERS(sb); i++) {
INIT_LIST_HEAD(&sbi->s_mb_largest_free_orders[i]);
rwlock_init(&sbi->s_mb_largest_free_orders_locks[i]);
}
spin_lock_init(&sbi->s_md_lock);
sbi->s_mb_free_pending = 0;
INIT_LIST_HEAD(&sbi->s_freed_data_list);
INIT_LIST_HEAD(&sbi->s_discard_list);
INIT_WORK(&sbi->s_discard_work, ext4_discard_work);
atomic_set(&sbi->s_retry_alloc_pending, 0);
sbi->s_mb_max_to_scan = MB_DEFAULT_MAX_TO_SCAN;
sbi->s_mb_min_to_scan = MB_DEFAULT_MIN_TO_SCAN;
sbi->s_mb_stats = MB_DEFAULT_STATS;
sbi->s_mb_stream_request = MB_DEFAULT_STREAM_THRESHOLD;
sbi->s_mb_order2_reqs = MB_DEFAULT_ORDER2_REQS;
sbi->s_mb_best_avail_max_trim_order = MB_DEFAULT_BEST_AVAIL_TRIM_ORDER;
/*
* The default group preallocation is 512, which for 4k block
* sizes translates to 2 megabytes. However for bigalloc file
* systems, this is probably too big (i.e, if the cluster size
* is 1 megabyte, then group preallocation size becomes half a
* gigabyte!). As a default, we will keep a two megabyte
* group pralloc size for cluster sizes up to 64k, and after
* that, we will force a minimum group preallocation size of
* 32 clusters. This translates to 8 megs when the cluster
* size is 256k, and 32 megs when the cluster size is 1 meg,
* which seems reasonable as a default.
*/
sbi->s_mb_group_prealloc = max(MB_DEFAULT_GROUP_PREALLOC >>
sbi->s_cluster_bits, 32);
/*
* If there is a s_stripe > 1, then we set the s_mb_group_prealloc
* to the lowest multiple of s_stripe which is bigger than
* the s_mb_group_prealloc as determined above. We want
* the preallocation size to be an exact multiple of the
* RAID stripe size so that preallocations don't fragment
* the stripes.
*/
if (sbi->s_stripe > 1) {
sbi->s_mb_group_prealloc = roundup(
sbi->s_mb_group_prealloc, EXT4_B2C(sbi, sbi->s_stripe));
}
sbi->s_locality_groups = alloc_percpu(struct ext4_locality_group);
if (sbi->s_locality_groups == NULL) {
ret = -ENOMEM;
goto out;
}
for_each_possible_cpu(i) {
struct ext4_locality_group *lg;
lg = per_cpu_ptr(sbi->s_locality_groups, i);
mutex_init(&lg->lg_mutex);
for (j = 0; j < PREALLOC_TB_SIZE; j++)
INIT_LIST_HEAD(&lg->lg_prealloc_list[j]);
spin_lock_init(&lg->lg_prealloc_lock);
}
if (bdev_nonrot(sb->s_bdev))
sbi->s_mb_max_linear_groups = 0;
else
sbi->s_mb_max_linear_groups = MB_DEFAULT_LINEAR_LIMIT;
/* init file for buddy data */
ret = ext4_mb_init_backend(sb);
if (ret != 0)
goto out_free_locality_groups;
return 0;
out_free_locality_groups:
free_percpu(sbi->s_locality_groups);
sbi->s_locality_groups = NULL;
out:
kfree(sbi->s_mb_avg_fragment_size);
kfree(sbi->s_mb_avg_fragment_size_locks);
kfree(sbi->s_mb_largest_free_orders);
kfree(sbi->s_mb_largest_free_orders_locks);
kfree(sbi->s_mb_offsets);
sbi->s_mb_offsets = NULL;
kfree(sbi->s_mb_maxs);
sbi->s_mb_maxs = NULL;
return ret;
}
/* need to called with the ext4 group lock held */
static int ext4_mb_cleanup_pa(struct ext4_group_info *grp)
{
struct ext4_prealloc_space *pa;
struct list_head *cur, *tmp;
int count = 0;
list_for_each_safe(cur, tmp, &grp->bb_prealloc_list) {
pa = list_entry(cur, struct ext4_prealloc_space, pa_group_list);
list_del(&pa->pa_group_list);
count++;
kmem_cache_free(ext4_pspace_cachep, pa);
}
return count;
}
int ext4_mb_release(struct super_block *sb)
{
ext4_group_t ngroups = ext4_get_groups_count(sb);
ext4_group_t i;
int num_meta_group_infos;
struct ext4_group_info *grinfo, ***group_info;
struct ext4_sb_info *sbi = EXT4_SB(sb);
struct kmem_cache *cachep = get_groupinfo_cache(sb->s_blocksize_bits);
int count;
if (test_opt(sb, DISCARD)) {
/*
* wait the discard work to drain all of ext4_free_data
*/
flush_work(&sbi->s_discard_work);
WARN_ON_ONCE(!list_empty(&sbi->s_discard_list));
}
if (sbi->s_group_info) {
for (i = 0; i < ngroups; i++) {
cond_resched();
grinfo = ext4_get_group_info(sb, i);
if (!grinfo)
continue;
mb_group_bb_bitmap_free(grinfo);
ext4_lock_group(sb, i);
count = ext4_mb_cleanup_pa(grinfo);
if (count)
mb_debug(sb, "mballoc: %d PAs left\n",
count);
ext4_unlock_group(sb, i);
kmem_cache_free(cachep, grinfo);
}
num_meta_group_infos = (ngroups +
EXT4_DESC_PER_BLOCK(sb) - 1) >>
EXT4_DESC_PER_BLOCK_BITS(sb);
rcu_read_lock();
group_info = rcu_dereference(sbi->s_group_info);
for (i = 0; i < num_meta_group_infos; i++)
kfree(group_info[i]);
kvfree(group_info);
rcu_read_unlock();
}
kfree(sbi->s_mb_avg_fragment_size);
kfree(sbi->s_mb_avg_fragment_size_locks);
kfree(sbi->s_mb_largest_free_orders);
kfree(sbi->s_mb_largest_free_orders_locks);
kfree(sbi->s_mb_offsets);
kfree(sbi->s_mb_maxs);
iput(sbi->s_buddy_cache);
if (sbi->s_mb_stats) {
ext4_msg(sb, KERN_INFO,
"mballoc: %u blocks %u reqs (%u success)",
atomic_read(&sbi->s_bal_allocated),
atomic_read(&sbi->s_bal_reqs),
atomic_read(&sbi->s_bal_success));
ext4_msg(sb, KERN_INFO,
"mballoc: %u extents scanned, %u groups scanned, %u goal hits, "
"%u 2^N hits, %u breaks, %u lost",
atomic_read(&sbi->s_bal_ex_scanned),
atomic_read(&sbi->s_bal_groups_scanned),
atomic_read(&sbi->s_bal_goals),
atomic_read(&sbi->s_bal_2orders),
atomic_read(&sbi->s_bal_breaks),
atomic_read(&sbi->s_mb_lost_chunks));
ext4_msg(sb, KERN_INFO,
"mballoc: %u generated and it took %llu",
atomic_read(&sbi->s_mb_buddies_generated),
atomic64_read(&sbi->s_mb_generation_time));
ext4_msg(sb, KERN_INFO,
"mballoc: %u preallocated, %u discarded",
atomic_read(&sbi->s_mb_preallocated),
atomic_read(&sbi->s_mb_discarded));
}
free_percpu(sbi->s_locality_groups);
return 0;
}
static inline int ext4_issue_discard(struct super_block *sb,
ext4_group_t block_group, ext4_grpblk_t cluster, int count,
struct bio **biop)
{
ext4_fsblk_t discard_block;
discard_block = (EXT4_C2B(EXT4_SB(sb), cluster) +
ext4_group_first_block_no(sb, block_group));
count = EXT4_C2B(EXT4_SB(sb), count);
trace_ext4_discard_blocks(sb,
(unsigned long long) discard_block, count);
if (biop) {
return __blkdev_issue_discard(sb->s_bdev,
(sector_t)discard_block << (sb->s_blocksize_bits - 9),
(sector_t)count << (sb->s_blocksize_bits - 9),
GFP_NOFS, biop);
} else
return sb_issue_discard(sb, discard_block, count, GFP_NOFS, 0);
}
static void ext4_free_data_in_buddy(struct super_block *sb,
struct ext4_free_data *entry)
{
struct ext4_buddy e4b;
struct ext4_group_info *db;
int err, count = 0;
mb_debug(sb, "gonna free %u blocks in group %u (0x%p):",
entry->efd_count, entry->efd_group, entry);
err = ext4_mb_load_buddy(sb, entry->efd_group, &e4b);
/* we expect to find existing buddy because it's pinned */
BUG_ON(err != 0);
spin_lock(&EXT4_SB(sb)->s_md_lock);
EXT4_SB(sb)->s_mb_free_pending -= entry->efd_count;
spin_unlock(&EXT4_SB(sb)->s_md_lock);
db = e4b.bd_info;
/* there are blocks to put in buddy to make them really free */
count += entry->efd_count;
ext4_lock_group(sb, entry->efd_group);
/* Take it out of per group rb tree */
rb_erase(&entry->efd_node, &(db->bb_free_root));
mb_free_blocks(NULL, &e4b, entry->efd_start_cluster, entry->efd_count);
/*
* Clear the trimmed flag for the group so that the next
* ext4_trim_fs can trim it.
* If the volume is mounted with -o discard, online discard
* is supported and the free blocks will be trimmed online.
*/
if (!test_opt(sb, DISCARD))
EXT4_MB_GRP_CLEAR_TRIMMED(db);
if (!db->bb_free_root.rb_node) {
/* No more items in the per group rb tree
* balance refcounts from ext4_mb_free_metadata()
*/
put_page(e4b.bd_buddy_page);
put_page(e4b.bd_bitmap_page);
}
ext4_unlock_group(sb, entry->efd_group);
ext4_mb_unload_buddy(&e4b);
mb_debug(sb, "freed %d blocks in 1 structures\n", count);
}
/*
* This function is called by the jbd2 layer once the commit has finished,
* so we know we can free the blocks that were released with that commit.
*/
void ext4_process_freed_data(struct super_block *sb, tid_t commit_tid)
{
struct ext4_sb_info *sbi = EXT4_SB(sb);
struct ext4_free_data *entry, *tmp;
struct list_head freed_data_list;
struct list_head *cut_pos = NULL;
bool wake;
INIT_LIST_HEAD(&freed_data_list);
spin_lock(&sbi->s_md_lock);
list_for_each_entry(entry, &sbi->s_freed_data_list, efd_list) {
if (entry->efd_tid != commit_tid)
break;
cut_pos = &entry->efd_list;
}
if (cut_pos)
list_cut_position(&freed_data_list, &sbi->s_freed_data_list,
cut_pos);
spin_unlock(&sbi->s_md_lock);
list_for_each_entry(entry, &freed_data_list, efd_list)
ext4_free_data_in_buddy(sb, entry);
if (test_opt(sb, DISCARD)) {
spin_lock(&sbi->s_md_lock);
wake = list_empty(&sbi->s_discard_list);
list_splice_tail(&freed_data_list, &sbi->s_discard_list);
spin_unlock(&sbi->s_md_lock);
if (wake)
queue_work(system_unbound_wq, &sbi->s_discard_work);
} else {
list_for_each_entry_safe(entry, tmp, &freed_data_list, efd_list)
kmem_cache_free(ext4_free_data_cachep, entry);
}
}
int __init ext4_init_mballoc(void)
{
ext4_pspace_cachep = KMEM_CACHE(ext4_prealloc_space,
SLAB_RECLAIM_ACCOUNT);
if (ext4_pspace_cachep == NULL)
goto out;
ext4_ac_cachep = KMEM_CACHE(ext4_allocation_context,
SLAB_RECLAIM_ACCOUNT);
if (ext4_ac_cachep == NULL)
goto out_pa_free;
ext4_free_data_cachep = KMEM_CACHE(ext4_free_data,
SLAB_RECLAIM_ACCOUNT);
if (ext4_free_data_cachep == NULL)
goto out_ac_free;
return 0;
out_ac_free:
kmem_cache_destroy(ext4_ac_cachep);
out_pa_free:
kmem_cache_destroy(ext4_pspace_cachep);
out:
return -ENOMEM;
}
void ext4_exit_mballoc(void)
{
/*
* Wait for completion of call_rcu()'s on ext4_pspace_cachep
* before destroying the slab cache.
*/
rcu_barrier();
kmem_cache_destroy(ext4_pspace_cachep);
kmem_cache_destroy(ext4_ac_cachep);
kmem_cache_destroy(ext4_free_data_cachep);
ext4_groupinfo_destroy_slabs();
}
/*
* Check quota and mark chosen space (ac->ac_b_ex) non-free in bitmaps
* Returns 0 if success or error code
*/
static noinline_for_stack int
ext4_mb_mark_diskspace_used(struct ext4_allocation_context *ac,
handle_t *handle, unsigned int reserv_clstrs)
{
struct buffer_head *bitmap_bh = NULL;
struct ext4_group_desc *gdp;
struct buffer_head *gdp_bh;
struct ext4_sb_info *sbi;
struct super_block *sb;
ext4_fsblk_t block;
int err, len;
BUG_ON(ac->ac_status != AC_STATUS_FOUND);
BUG_ON(ac->ac_b_ex.fe_len <= 0);
sb = ac->ac_sb;
sbi = EXT4_SB(sb);
bitmap_bh = ext4_read_block_bitmap(sb, ac->ac_b_ex.fe_group);
if (IS_ERR(bitmap_bh)) {
return PTR_ERR(bitmap_bh);
}
BUFFER_TRACE(bitmap_bh, "getting write access");
err = ext4_journal_get_write_access(handle, sb, bitmap_bh,
EXT4_JTR_NONE);
if (err)
goto out_err;
err = -EIO;
gdp = ext4_get_group_desc(sb, ac->ac_b_ex.fe_group, &gdp_bh);
if (!gdp)
goto out_err;
ext4_debug("using block group %u(%d)\n", ac->ac_b_ex.fe_group,
ext4_free_group_clusters(sb, gdp));
BUFFER_TRACE(gdp_bh, "get_write_access");
err = ext4_journal_get_write_access(handle, sb, gdp_bh, EXT4_JTR_NONE);
if (err)
goto out_err;
block = ext4_grp_offs_to_block(sb, &ac->ac_b_ex);
len = EXT4_C2B(sbi, ac->ac_b_ex.fe_len);
if (!ext4_inode_block_valid(ac->ac_inode, block, len)) {
ext4_error(sb, "Allocating blocks %llu-%llu which overlap "
"fs metadata", block, block+len);
/* File system mounted not to panic on error
* Fix the bitmap and return EFSCORRUPTED
* We leak some of the blocks here.
*/
ext4_lock_group(sb, ac->ac_b_ex.fe_group);
mb_set_bits(bitmap_bh->b_data, ac->ac_b_ex.fe_start,
ac->ac_b_ex.fe_len);
ext4_unlock_group(sb, ac->ac_b_ex.fe_group);
err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh);
if (!err)
err = -EFSCORRUPTED;
goto out_err;
}
ext4_lock_group(sb, ac->ac_b_ex.fe_group);
#ifdef AGGRESSIVE_CHECK
{
int i;
for (i = 0; i < ac->ac_b_ex.fe_len; i++) {
BUG_ON(mb_test_bit(ac->ac_b_ex.fe_start + i,
bitmap_bh->b_data));
}
}
#endif
mb_set_bits(bitmap_bh->b_data, ac->ac_b_ex.fe_start,
ac->ac_b_ex.fe_len);
if (ext4_has_group_desc_csum(sb) &&
(gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT))) {
gdp->bg_flags &= cpu_to_le16(~EXT4_BG_BLOCK_UNINIT);
ext4_free_group_clusters_set(sb, gdp,
ext4_free_clusters_after_init(sb,
ac->ac_b_ex.fe_group, gdp));
}
len = ext4_free_group_clusters(sb, gdp) - ac->ac_b_ex.fe_len;
ext4_free_group_clusters_set(sb, gdp, len);
ext4_block_bitmap_csum_set(sb, gdp, bitmap_bh);
ext4_group_desc_csum_set(sb, ac->ac_b_ex.fe_group, gdp);
ext4_unlock_group(sb, ac->ac_b_ex.fe_group);
percpu_counter_sub(&sbi->s_freeclusters_counter, ac->ac_b_ex.fe_len);
/*
* Now reduce the dirty block count also. Should not go negative
*/
if (!(ac->ac_flags & EXT4_MB_DELALLOC_RESERVED))
/* release all the reserved blocks if non delalloc */
percpu_counter_sub(&sbi->s_dirtyclusters_counter,
reserv_clstrs);
if (sbi->s_log_groups_per_flex) {
ext4_group_t flex_group = ext4_flex_group(sbi,
ac->ac_b_ex.fe_group);
atomic64_sub(ac->ac_b_ex.fe_len,
&sbi_array_rcu_deref(sbi, s_flex_groups,
flex_group)->free_clusters);
}
err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh);
if (err)
goto out_err;
err = ext4_handle_dirty_metadata(handle, NULL, gdp_bh);
out_err:
brelse(bitmap_bh);
return err;
}
/*
* Idempotent helper for Ext4 fast commit replay path to set the state of
* blocks in bitmaps and update counters.
*/
void ext4_mb_mark_bb(struct super_block *sb, ext4_fsblk_t block,
int len, int state)
{
struct buffer_head *bitmap_bh = NULL;
struct ext4_group_desc *gdp;
struct buffer_head *gdp_bh;
struct ext4_sb_info *sbi = EXT4_SB(sb);
ext4_group_t group;
ext4_grpblk_t blkoff;
int i, err;
int already;
unsigned int clen, clen_changed, thisgrp_len;
while (len > 0) {
ext4_get_group_no_and_offset(sb, block, &group, &blkoff);
/*
* Check to see if we are freeing blocks across a group
* boundary.
* In case of flex_bg, this can happen that (block, len) may
* span across more than one group. In that case we need to
* get the corresponding group metadata to work with.
* For this we have goto again loop.
*/
thisgrp_len = min_t(unsigned int, (unsigned int)len,
EXT4_BLOCKS_PER_GROUP(sb) - EXT4_C2B(sbi, blkoff));
clen = EXT4_NUM_B2C(sbi, thisgrp_len);
if (!ext4_sb_block_valid(sb, NULL, block, thisgrp_len)) {
ext4_error(sb, "Marking blocks in system zone - "
"Block = %llu, len = %u",
block, thisgrp_len);
bitmap_bh = NULL;
break;
}
bitmap_bh = ext4_read_block_bitmap(sb, group);
if (IS_ERR(bitmap_bh)) {
err = PTR_ERR(bitmap_bh);
bitmap_bh = NULL;
break;
}
err = -EIO;
gdp = ext4_get_group_desc(sb, group, &gdp_bh);
if (!gdp)
break;
ext4_lock_group(sb, group);
already = 0;
for (i = 0; i < clen; i++)
if (!mb_test_bit(blkoff + i, bitmap_bh->b_data) ==
!state)
already++;
clen_changed = clen - already;
if (state)
mb_set_bits(bitmap_bh->b_data, blkoff, clen);
else
mb_clear_bits(bitmap_bh->b_data, blkoff, clen);
if (ext4_has_group_desc_csum(sb) &&
(gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT))) {
gdp->bg_flags &= cpu_to_le16(~EXT4_BG_BLOCK_UNINIT);
ext4_free_group_clusters_set(sb, gdp,
ext4_free_clusters_after_init(sb, group, gdp));
}
if (state)
clen = ext4_free_group_clusters(sb, gdp) - clen_changed;
else
clen = ext4_free_group_clusters(sb, gdp) + clen_changed;
ext4_free_group_clusters_set(sb, gdp, clen);
ext4_block_bitmap_csum_set(sb, gdp, bitmap_bh);
ext4_group_desc_csum_set(sb, group, gdp);
ext4_unlock_group(sb, group);
if (sbi->s_log_groups_per_flex) {
ext4_group_t flex_group = ext4_flex_group(sbi, group);
struct flex_groups *fg = sbi_array_rcu_deref(sbi,
s_flex_groups, flex_group);
if (state)
atomic64_sub(clen_changed, &fg->free_clusters);
else
atomic64_add(clen_changed, &fg->free_clusters);
}
err = ext4_handle_dirty_metadata(NULL, NULL, bitmap_bh);
if (err)
break;
sync_dirty_buffer(bitmap_bh);
err = ext4_handle_dirty_metadata(NULL, NULL, gdp_bh);
sync_dirty_buffer(gdp_bh);
if (err)
break;
block += thisgrp_len;
len -= thisgrp_len;
brelse(bitmap_bh);
BUG_ON(len < 0);
}
if (err)
brelse(bitmap_bh);
}
/*
* here we normalize request for locality group
* Group request are normalized to s_mb_group_prealloc, which goes to
* s_strip if we set the same via mount option.
* s_mb_group_prealloc can be configured via
* /sys/fs/ext4/<partition>/mb_group_prealloc
*
* XXX: should we try to preallocate more than the group has now?
*/
static void ext4_mb_normalize_group_request(struct ext4_allocation_context *ac)
{
struct super_block *sb = ac->ac_sb;
struct ext4_locality_group *lg = ac->ac_lg;
BUG_ON(lg == NULL);
ac->ac_g_ex.fe_len = EXT4_SB(sb)->s_mb_group_prealloc;
mb_debug(sb, "goal %u blocks for locality group\n", ac->ac_g_ex.fe_len);
}
/*
* This function returns the next element to look at during inode
* PA rbtree walk. We assume that we have held the inode PA rbtree lock
* (ei->i_prealloc_lock)
*
* new_start The start of the range we want to compare
* cur_start The existing start that we are comparing against
* node The node of the rb_tree
*/
static inline struct rb_node*
ext4_mb_pa_rb_next_iter(ext4_lblk_t new_start, ext4_lblk_t cur_start, struct rb_node *node)
{
if (new_start < cur_start)
return node->rb_left;
else
return node->rb_right;
}
static inline void
ext4_mb_pa_assert_overlap(struct ext4_allocation_context *ac,
ext4_lblk_t start, ext4_lblk_t end)
{
struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
struct ext4_inode_info *ei = EXT4_I(ac->ac_inode);
struct ext4_prealloc_space *tmp_pa;
ext4_lblk_t tmp_pa_start, tmp_pa_end;
struct rb_node *iter;
read_lock(&ei->i_prealloc_lock);
for (iter = ei->i_prealloc_node.rb_node; iter;
iter = ext4_mb_pa_rb_next_iter(start, tmp_pa_start, iter)) {
tmp_pa = rb_entry(iter, struct ext4_prealloc_space,
pa_node.inode_node);
tmp_pa_start = tmp_pa->pa_lstart;
tmp_pa_end = tmp_pa->pa_lstart + EXT4_C2B(sbi, tmp_pa->pa_len);
spin_lock(&tmp_pa->pa_lock);
if (tmp_pa->pa_deleted == 0)
BUG_ON(!(start >= tmp_pa_end || end <= tmp_pa_start));
spin_unlock(&tmp_pa->pa_lock);
}
read_unlock(&ei->i_prealloc_lock);
}
/*
* Given an allocation context "ac" and a range "start", "end", check
* and adjust boundaries if the range overlaps with any of the existing
* preallocatoins stored in the corresponding inode of the allocation context.
*
* Parameters:
* ac allocation context
* start start of the new range
* end end of the new range
*/
static inline void
ext4_mb_pa_adjust_overlap(struct ext4_allocation_context *ac,
ext4_lblk_t *start, ext4_lblk_t *end)
{
struct ext4_inode_info *ei = EXT4_I(ac->ac_inode);
struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
struct ext4_prealloc_space *tmp_pa = NULL, *left_pa = NULL, *right_pa = NULL;
struct rb_node *iter;
ext4_lblk_t new_start, new_end;
ext4_lblk_t tmp_pa_start, tmp_pa_end, left_pa_end = -1, right_pa_start = -1;
new_start = *start;
new_end = *end;
/*
* Adjust the normalized range so that it doesn't overlap with any
* existing preallocated blocks(PAs). Make sure to hold the rbtree lock
* so it doesn't change underneath us.
*/
read_lock(&ei->i_prealloc_lock);
/* Step 1: find any one immediate neighboring PA of the normalized range */
for (iter = ei->i_prealloc_node.rb_node; iter;
iter = ext4_mb_pa_rb_next_iter(ac->ac_o_ex.fe_logical,
tmp_pa_start, iter)) {
tmp_pa = rb_entry(iter, struct ext4_prealloc_space,
pa_node.inode_node);
tmp_pa_start = tmp_pa->pa_lstart;
tmp_pa_end = tmp_pa->pa_lstart + EXT4_C2B(sbi, tmp_pa->pa_len);
/* PA must not overlap original request */
spin_lock(&tmp_pa->pa_lock);
if (tmp_pa->pa_deleted == 0)
BUG_ON(!(ac->ac_o_ex.fe_logical >= tmp_pa_end ||
ac->ac_o_ex.fe_logical < tmp_pa_start));
spin_unlock(&tmp_pa->pa_lock);
}
/*
* Step 2: check if the found PA is left or right neighbor and
* get the other neighbor
*/
if (tmp_pa) {
if (tmp_pa->pa_lstart < ac->ac_o_ex.fe_logical) {
struct rb_node *tmp;
left_pa = tmp_pa;
tmp = rb_next(&left_pa->pa_node.inode_node);
if (tmp) {
right_pa = rb_entry(tmp,
struct ext4_prealloc_space,
pa_node.inode_node);
}
} else {
struct rb_node *tmp;
right_pa = tmp_pa;
tmp = rb_prev(&right_pa->pa_node.inode_node);
if (tmp) {
left_pa = rb_entry(tmp,
struct ext4_prealloc_space,
pa_node.inode_node);
}
}
}
/* Step 3: get the non deleted neighbors */
if (left_pa) {
for (iter = &left_pa->pa_node.inode_node;;
iter = rb_prev(iter)) {
if (!iter) {
left_pa = NULL;
break;
}
tmp_pa = rb_entry(iter, struct ext4_prealloc_space,
pa_node.inode_node);
left_pa = tmp_pa;
spin_lock(&tmp_pa->pa_lock);
if (tmp_pa->pa_deleted == 0) {
spin_unlock(&tmp_pa->pa_lock);
break;
}
spin_unlock(&tmp_pa->pa_lock);
}
}
if (right_pa) {
for (iter = &right_pa->pa_node.inode_node;;
iter = rb_next(iter)) {
if (!iter) {
right_pa = NULL;
break;
}
tmp_pa = rb_entry(iter, struct ext4_prealloc_space,
pa_node.inode_node);
right_pa = tmp_pa;
spin_lock(&tmp_pa->pa_lock);
if (tmp_pa->pa_deleted == 0) {
spin_unlock(&tmp_pa->pa_lock);
break;
}
spin_unlock(&tmp_pa->pa_lock);
}
}
if (left_pa) {
left_pa_end =
left_pa->pa_lstart + EXT4_C2B(sbi, left_pa->pa_len);
BUG_ON(left_pa_end > ac->ac_o_ex.fe_logical);
}
if (right_pa) {
right_pa_start = right_pa->pa_lstart;
BUG_ON(right_pa_start <= ac->ac_o_ex.fe_logical);
}
/* Step 4: trim our normalized range to not overlap with the neighbors */
if (left_pa) {
if (left_pa_end > new_start)
new_start = left_pa_end;
}
if (right_pa) {
if (right_pa_start < new_end)
new_end = right_pa_start;
}
read_unlock(&ei->i_prealloc_lock);
/* XXX: extra loop to check we really don't overlap preallocations */
ext4_mb_pa_assert_overlap(ac, new_start, new_end);
*start = new_start;
*end = new_end;
}
/*
* Normalization means making request better in terms of
* size and alignment
*/
static noinline_for_stack void
ext4_mb_normalize_request(struct ext4_allocation_context *ac,
struct ext4_allocation_request *ar)
{
struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
struct ext4_super_block *es = sbi->s_es;
int bsbits, max;
ext4_lblk_t end;
loff_t size, start_off;
loff_t orig_size __maybe_unused;
ext4_lblk_t start;
/* do normalize only data requests, metadata requests
do not need preallocation */
if (!(ac->ac_flags & EXT4_MB_HINT_DATA))
return;
/* sometime caller may want exact blocks */
if (unlikely(ac->ac_flags & EXT4_MB_HINT_GOAL_ONLY))
return;
/* caller may indicate that preallocation isn't
* required (it's a tail, for example) */
if (ac->ac_flags & EXT4_MB_HINT_NOPREALLOC)
return;
if (ac->ac_flags & EXT4_MB_HINT_GROUP_ALLOC) {
ext4_mb_normalize_group_request(ac);
return ;
}
bsbits = ac->ac_sb->s_blocksize_bits;
/* first, let's learn actual file size
* given current request is allocated */
size = ac->ac_o_ex.fe_logical + EXT4_C2B(sbi, ac->ac_o_ex.fe_len);
size = size << bsbits;
if (size < i_size_read(ac->ac_inode))
size = i_size_read(ac->ac_inode);
orig_size = size;
/* max size of free chunks */
max = 2 << bsbits;
#define NRL_CHECK_SIZE(req, size, max, chunk_size) \
(req <= (size) || max <= (chunk_size))
/* first, try to predict filesize */
/* XXX: should this table be tunable? */
start_off = 0;
if (size <= 16 * 1024) {
size = 16 * 1024;
} else if (size <= 32 * 1024) {
size = 32 * 1024;
} else if (size <= 64 * 1024) {
size = 64 * 1024;
} else if (size <= 128 * 1024) {
size = 128 * 1024;
} else if (size <= 256 * 1024) {
size = 256 * 1024;
} else if (size <= 512 * 1024) {
size = 512 * 1024;
} else if (size <= 1024 * 1024) {
size = 1024 * 1024;
} else if (NRL_CHECK_SIZE(size, 4 * 1024 * 1024, max, 2 * 1024)) {
start_off = ((loff_t)ac->ac_o_ex.fe_logical >>
(21 - bsbits)) << 21;
size = 2 * 1024 * 1024;
} else if (NRL_CHECK_SIZE(size, 8 * 1024 * 1024, max, 4 * 1024)) {
start_off = ((loff_t)ac->ac_o_ex.fe_logical >>
(22 - bsbits)) << 22;
size = 4 * 1024 * 1024;
} else if (NRL_CHECK_SIZE(EXT4_C2B(sbi, ac->ac_o_ex.fe_len),
(8<<20)>>bsbits, max, 8 * 1024)) {
start_off = ((loff_t)ac->ac_o_ex.fe_logical >>
(23 - bsbits)) << 23;
size = 8 * 1024 * 1024;
} else {
start_off = (loff_t) ac->ac_o_ex.fe_logical << bsbits;
size = (loff_t) EXT4_C2B(sbi,
ac->ac_o_ex.fe_len) << bsbits;
}
size = size >> bsbits;
start = start_off >> bsbits;
/*
* For tiny groups (smaller than 8MB) the chosen allocation
* alignment may be larger than group size. Make sure the
* alignment does not move allocation to a different group which
* makes mballoc fail assertions later.
*/
start = max(start, rounddown(ac->ac_o_ex.fe_logical,
(ext4_lblk_t)EXT4_BLOCKS_PER_GROUP(ac->ac_sb)));
/* don't cover already allocated blocks in selected range */
if (ar->pleft && start <= ar->lleft) {
size -= ar->lleft + 1 - start;
start = ar->lleft + 1;
}
if (ar->pright && start + size - 1 >= ar->lright)
size -= start + size - ar->lright;
/*
* Trim allocation request for filesystems with artificially small
* groups.
*/
if (size > EXT4_BLOCKS_PER_GROUP(ac->ac_sb))
size = EXT4_BLOCKS_PER_GROUP(ac->ac_sb);
end = start + size;
ext4_mb_pa_adjust_overlap(ac, &start, &end);
size = end - start;
/*
* In this function "start" and "size" are normalized for better
* alignment and length such that we could preallocate more blocks.
* This normalization is done such that original request of
* ac->ac_o_ex.fe_logical & fe_len should always lie within "start" and
* "size" boundaries.
* (Note fe_len can be relaxed since FS block allocation API does not
* provide gurantee on number of contiguous blocks allocation since that
* depends upon free space left, etc).
* In case of inode pa, later we use the allocated blocks
* [pa_pstart + fe_logical - pa_lstart, fe_len/size] from the preallocated
* range of goal/best blocks [start, size] to put it at the
* ac_o_ex.fe_logical extent of this inode.
* (See ext4_mb_use_inode_pa() for more details)
*/
if (start + size <= ac->ac_o_ex.fe_logical ||
start > ac->ac_o_ex.fe_logical) {
ext4_msg(ac->ac_sb, KERN_ERR,
"start %lu, size %lu, fe_logical %lu",
(unsigned long) start, (unsigned long) size,
(unsigned long) ac->ac_o_ex.fe_logical);
BUG();
}
BUG_ON(size <= 0 || size > EXT4_BLOCKS_PER_GROUP(ac->ac_sb));
/* now prepare goal request */
/* XXX: is it better to align blocks WRT to logical
* placement or satisfy big request as is */
ac->ac_g_ex.fe_logical = start;
ac->ac_g_ex.fe_len = EXT4_NUM_B2C(sbi, size);
ac->ac_orig_goal_len = ac->ac_g_ex.fe_len;
/* define goal start in order to merge */
if (ar->pright && (ar->lright == (start + size)) &&
ar->pright >= size &&
ar->pright - size >= le32_to_cpu(es->s_first_data_block)) {
/* merge to the right */
ext4_get_group_no_and_offset(ac->ac_sb, ar->pright - size,
&ac->ac_g_ex.fe_group,
&ac->ac_g_ex.fe_start);
ac->ac_flags |= EXT4_MB_HINT_TRY_GOAL;
}
if (ar->pleft && (ar->lleft + 1 == start) &&
ar->pleft + 1 < ext4_blocks_count(es)) {
/* merge to the left */
ext4_get_group_no_and_offset(ac->ac_sb, ar->pleft + 1,
&ac->ac_g_ex.fe_group,
&ac->ac_g_ex.fe_start);
ac->ac_flags |= EXT4_MB_HINT_TRY_GOAL;
}
mb_debug(ac->ac_sb, "goal: %lld(was %lld) blocks at %u\n", size,
orig_size, start);
}
static void ext4_mb_collect_stats(struct ext4_allocation_context *ac)
{
struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
if (sbi->s_mb_stats && ac->ac_g_ex.fe_len >= 1) {
atomic_inc(&sbi->s_bal_reqs);
atomic_add(ac->ac_b_ex.fe_len, &sbi->s_bal_allocated);
if (ac->ac_b_ex.fe_len >= ac->ac_o_ex.fe_len)
atomic_inc(&sbi->s_bal_success);
atomic_add(ac->ac_found, &sbi->s_bal_ex_scanned);
for (int i=0; i<EXT4_MB_NUM_CRS; i++) {
atomic_add(ac->ac_cX_found[i], &sbi->s_bal_cX_ex_scanned[i]);
}
atomic_add(ac->ac_groups_scanned, &sbi->s_bal_groups_scanned);
if (ac->ac_g_ex.fe_start == ac->ac_b_ex.fe_start &&
ac->ac_g_ex.fe_group == ac->ac_b_ex.fe_group)
atomic_inc(&sbi->s_bal_goals);
/* did we allocate as much as normalizer originally wanted? */
if (ac->ac_f_ex.fe_len == ac->ac_orig_goal_len)
atomic_inc(&sbi->s_bal_len_goals);
if (ac->ac_found > sbi->s_mb_max_to_scan)
atomic_inc(&sbi->s_bal_breaks);
}
if (ac->ac_op == EXT4_MB_HISTORY_ALLOC)
trace_ext4_mballoc_alloc(ac);
else
trace_ext4_mballoc_prealloc(ac);
}
/*
* Called on failure; free up any blocks from the inode PA for this
* context. We don't need this for MB_GROUP_PA because we only change
* pa_free in ext4_mb_release_context(), but on failure, we've already
* zeroed out ac->ac_b_ex.fe_len, so group_pa->pa_free is not changed.
*/
static void ext4_discard_allocated_blocks(struct ext4_allocation_context *ac)
{
struct ext4_prealloc_space *pa = ac->ac_pa;
struct ext4_buddy e4b;
int err;
if (pa == NULL) {
if (ac->ac_f_ex.fe_len == 0)
return;
err = ext4_mb_load_buddy(ac->ac_sb, ac->ac_f_ex.fe_group, &e4b);
if (WARN_RATELIMIT(err,
"ext4: mb_load_buddy failed (%d)", err))
/*
* This should never happen since we pin the
* pages in the ext4_allocation_context so
* ext4_mb_load_buddy() should never fail.
*/
return;
ext4_lock_group(ac->ac_sb, ac->ac_f_ex.fe_group);
mb_free_blocks(ac->ac_inode, &e4b, ac->ac_f_ex.fe_start,
ac->ac_f_ex.fe_len);
ext4_unlock_group(ac->ac_sb, ac->ac_f_ex.fe_group);
ext4_mb_unload_buddy(&e4b);
return;
}
if (pa->pa_type == MB_INODE_PA) {
spin_lock(&pa->pa_lock);
pa->pa_free += ac->ac_b_ex.fe_len;
spin_unlock(&pa->pa_lock);
}
}
/*
* use blocks preallocated to inode
*/
static void ext4_mb_use_inode_pa(struct ext4_allocation_context *ac,
struct ext4_prealloc_space *pa)
{
struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
ext4_fsblk_t start;
ext4_fsblk_t end;
int len;
/* found preallocated blocks, use them */
start = pa->pa_pstart + (ac->ac_o_ex.fe_logical - pa->pa_lstart);
end = min(pa->pa_pstart + EXT4_C2B(sbi, pa->pa_len),
start + EXT4_C2B(sbi, ac->ac_o_ex.fe_len));
len = EXT4_NUM_B2C(sbi, end - start);
ext4_get_group_no_and_offset(ac->ac_sb, start, &ac->ac_b_ex.fe_group,
&ac->ac_b_ex.fe_start);
ac->ac_b_ex.fe_len = len;
ac->ac_status = AC_STATUS_FOUND;
ac->ac_pa = pa;
BUG_ON(start < pa->pa_pstart);
BUG_ON(end > pa->pa_pstart + EXT4_C2B(sbi, pa->pa_len));
BUG_ON(pa->pa_free < len);
BUG_ON(ac->ac_b_ex.fe_len <= 0);
pa->pa_free -= len;
mb_debug(ac->ac_sb, "use %llu/%d from inode pa %p\n", start, len, pa);
}
/*
* use blocks preallocated to locality group
*/
static void ext4_mb_use_group_pa(struct ext4_allocation_context *ac,
struct ext4_prealloc_space *pa)
{
unsigned int len = ac->ac_o_ex.fe_len;
ext4_get_group_no_and_offset(ac->ac_sb, pa->pa_pstart,
&ac->ac_b_ex.fe_group,
&ac->ac_b_ex.fe_start);
ac->ac_b_ex.fe_len = len;
ac->ac_status = AC_STATUS_FOUND;
ac->ac_pa = pa;
/* we don't correct pa_pstart or pa_len here to avoid
* possible race when the group is being loaded concurrently
* instead we correct pa later, after blocks are marked
* in on-disk bitmap -- see ext4_mb_release_context()
* Other CPUs are prevented from allocating from this pa by lg_mutex
*/
mb_debug(ac->ac_sb, "use %u/%u from group pa %p\n",
pa->pa_lstart, len, pa);
}
/*
* Return the prealloc space that have minimal distance
* from the goal block. @cpa is the prealloc
* space that is having currently known minimal distance
* from the goal block.
*/
static struct ext4_prealloc_space *
ext4_mb_check_group_pa(ext4_fsblk_t goal_block,
struct ext4_prealloc_space *pa,
struct ext4_prealloc_space *cpa)
{
ext4_fsblk_t cur_distance, new_distance;
if (cpa == NULL) {
atomic_inc(&pa->pa_count);
return pa;
}
cur_distance = abs(goal_block - cpa->pa_pstart);
new_distance = abs(goal_block - pa->pa_pstart);
if (cur_distance <= new_distance)
return cpa;
/* drop the previous reference */
atomic_dec(&cpa->pa_count);
atomic_inc(&pa->pa_count);
return pa;
}
/*
* check if found pa meets EXT4_MB_HINT_GOAL_ONLY
*/
static bool
ext4_mb_pa_goal_check(struct ext4_allocation_context *ac,
struct ext4_prealloc_space *pa)
{
struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
ext4_fsblk_t start;
if (likely(!(ac->ac_flags & EXT4_MB_HINT_GOAL_ONLY)))
return true;
/*
* If EXT4_MB_HINT_GOAL_ONLY is set, ac_g_ex will not be adjusted
* in ext4_mb_normalize_request and will keep same with ac_o_ex
* from ext4_mb_initialize_context. Choose ac_g_ex here to keep
* consistent with ext4_mb_find_by_goal.
*/
start = pa->pa_pstart +
(ac->ac_g_ex.fe_logical - pa->pa_lstart);
if (ext4_grp_offs_to_block(ac->ac_sb, &ac->ac_g_ex) != start)
return false;
if (ac->ac_g_ex.fe_len > pa->pa_len -
EXT4_B2C(sbi, ac->ac_g_ex.fe_logical - pa->pa_lstart))
return false;
return true;
}
/*
* search goal blocks in preallocated space
*/
static noinline_for_stack bool
ext4_mb_use_preallocated(struct ext4_allocation_context *ac)
{
struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
int order, i;
struct ext4_inode_info *ei = EXT4_I(ac->ac_inode);
struct ext4_locality_group *lg;
struct ext4_prealloc_space *tmp_pa, *cpa = NULL;
ext4_lblk_t tmp_pa_start, tmp_pa_end;
struct rb_node *iter;
ext4_fsblk_t goal_block;
/* only data can be preallocated */
if (!(ac->ac_flags & EXT4_MB_HINT_DATA))
return false;
/* first, try per-file preallocation */
read_lock(&ei->i_prealloc_lock);
for (iter = ei->i_prealloc_node.rb_node; iter;
iter = ext4_mb_pa_rb_next_iter(ac->ac_o_ex.fe_logical,
tmp_pa_start, iter)) {
tmp_pa = rb_entry(iter, struct ext4_prealloc_space,
pa_node.inode_node);
/* all fields in this condition don't change,
* so we can skip locking for them */
tmp_pa_start = tmp_pa->pa_lstart;
tmp_pa_end = tmp_pa->pa_lstart + EXT4_C2B(sbi, tmp_pa->pa_len);
/* original request start doesn't lie in this PA */
if (ac->ac_o_ex.fe_logical < tmp_pa_start ||
ac->ac_o_ex.fe_logical >= tmp_pa_end)
continue;
/* non-extent files can't have physical blocks past 2^32 */
if (!(ext4_test_inode_flag(ac->ac_inode, EXT4_INODE_EXTENTS)) &&
(tmp_pa->pa_pstart + EXT4_C2B(sbi, tmp_pa->pa_len) >
EXT4_MAX_BLOCK_FILE_PHYS)) {
/*
* Since PAs don't overlap, we won't find any
* other PA to satisfy this.
*/
break;
}
/* found preallocated blocks, use them */
spin_lock(&tmp_pa->pa_lock);
if (tmp_pa->pa_deleted == 0 && tmp_pa->pa_free &&
likely(ext4_mb_pa_goal_check(ac, tmp_pa))) {
atomic_inc(&tmp_pa->pa_count);
ext4_mb_use_inode_pa(ac, tmp_pa);
spin_unlock(&tmp_pa->pa_lock);
read_unlock(&ei->i_prealloc_lock);
return true;
}
spin_unlock(&tmp_pa->pa_lock);
}
read_unlock(&ei->i_prealloc_lock);
/* can we use group allocation? */
if (!(ac->ac_flags & EXT4_MB_HINT_GROUP_ALLOC))
return false;
/* inode may have no locality group for some reason */
lg = ac->ac_lg;
if (lg == NULL)
return false;
order = fls(ac->ac_o_ex.fe_len) - 1;
if (order > PREALLOC_TB_SIZE - 1)
/* The max size of hash table is PREALLOC_TB_SIZE */
order = PREALLOC_TB_SIZE - 1;
goal_block = ext4_grp_offs_to_block(ac->ac_sb, &ac->ac_g_ex);
/*
* search for the prealloc space that is having
* minimal distance from the goal block.
*/
for (i = order; i < PREALLOC_TB_SIZE; i++) {
rcu_read_lock();
list_for_each_entry_rcu(tmp_pa, &lg->lg_prealloc_list[i],
pa_node.lg_list) {
spin_lock(&tmp_pa->pa_lock);
if (tmp_pa->pa_deleted == 0 &&
tmp_pa->pa_free >= ac->ac_o_ex.fe_len) {
cpa = ext4_mb_check_group_pa(goal_block,
tmp_pa, cpa);
}
spin_unlock(&tmp_pa->pa_lock);
}
rcu_read_unlock();
}
if (cpa) {
ext4_mb_use_group_pa(ac, cpa);
return true;
}
return false;
}
/*
* the function goes through all block freed in the group
* but not yet committed and marks them used in in-core bitmap.
* buddy must be generated from this bitmap
* Need to be called with the ext4 group lock held
*/
static void ext4_mb_generate_from_freelist(struct super_block *sb, void *bitmap,
ext4_group_t group)
{
struct rb_node *n;
struct ext4_group_info *grp;
struct ext4_free_data *entry;
grp = ext4_get_group_info(sb, group);
if (!grp)
return;
n = rb_first(&(grp->bb_free_root));
while (n) {
entry = rb_entry(n, struct ext4_free_data, efd_node);
mb_set_bits(bitmap, entry->efd_start_cluster, entry->efd_count);
n = rb_next(n);
}
return;
}
/*
* the function goes through all preallocation in this group and marks them
* used in in-core bitmap. buddy must be generated from this bitmap
* Need to be called with ext4 group lock held
*/
static noinline_for_stack
void ext4_mb_generate_from_pa(struct super_block *sb, void *bitmap,
ext4_group_t group)
{
struct ext4_group_info *grp = ext4_get_group_info(sb, group);
struct ext4_prealloc_space *pa;
struct list_head *cur;
ext4_group_t groupnr;
ext4_grpblk_t start;
int preallocated = 0;
int len;
if (!grp)
return;
/* all form of preallocation discards first load group,
* so the only competing code is preallocation use.
* we don't need any locking here
* notice we do NOT ignore preallocations with pa_deleted
* otherwise we could leave used blocks available for
* allocation in buddy when concurrent ext4_mb_put_pa()
* is dropping preallocation
*/
list_for_each(cur, &grp->bb_prealloc_list) {
pa = list_entry(cur, struct ext4_prealloc_space, pa_group_list);
spin_lock(&pa->pa_lock);
ext4_get_group_no_and_offset(sb, pa->pa_pstart,
&groupnr, &start);
len = pa->pa_len;
spin_unlock(&pa->pa_lock);
if (unlikely(len == 0))
continue;
BUG_ON(groupnr != group);
mb_set_bits(bitmap, start, len);
preallocated += len;
}
mb_debug(sb, "preallocated %d for group %u\n", preallocated, group);
}
static void ext4_mb_mark_pa_deleted(struct super_block *sb,
struct ext4_prealloc_space *pa)
{
struct ext4_inode_info *ei;
if (pa->pa_deleted) {
ext4_warning(sb, "deleted pa, type:%d, pblk:%llu, lblk:%u, len:%d\n",
pa->pa_type, pa->pa_pstart, pa->pa_lstart,
pa->pa_len);
return;
}
pa->pa_deleted = 1;
if (pa->pa_type == MB_INODE_PA) {
ei = EXT4_I(pa->pa_inode);
atomic_dec(&ei->i_prealloc_active);
}
}
static inline void ext4_mb_pa_free(struct ext4_prealloc_space *pa)
{
BUG_ON(!pa);
BUG_ON(atomic_read(&pa->pa_count));
BUG_ON(pa->pa_deleted == 0);
kmem_cache_free(ext4_pspace_cachep, pa);
}
static void ext4_mb_pa_callback(struct rcu_head *head)
{
struct ext4_prealloc_space *pa;
pa = container_of(head, struct ext4_prealloc_space, u.pa_rcu);
ext4_mb_pa_free(pa);
}
/*
* drops a reference to preallocated space descriptor
* if this was the last reference and the space is consumed
*/
static void ext4_mb_put_pa(struct ext4_allocation_context *ac,
struct super_block *sb, struct ext4_prealloc_space *pa)
{
ext4_group_t grp;
ext4_fsblk_t grp_blk;
struct ext4_inode_info *ei = EXT4_I(ac->ac_inode);
/* in this short window concurrent discard can set pa_deleted */
spin_lock(&pa->pa_lock);
if (!atomic_dec_and_test(&pa->pa_count) || pa->pa_free != 0) {
spin_unlock(&pa->pa_lock);
return;
}
if (pa->pa_deleted == 1) {
spin_unlock(&pa->pa_lock);
return;
}
ext4_mb_mark_pa_deleted(sb, pa);
spin_unlock(&pa->pa_lock);
grp_blk = pa->pa_pstart;
/*
* If doing group-based preallocation, pa_pstart may be in the
* next group when pa is used up
*/
if (pa->pa_type == MB_GROUP_PA)
grp_blk--;
grp = ext4_get_group_number(sb, grp_blk);
/*
* possible race:
*
* P1 (buddy init) P2 (regular allocation)
* find block B in PA
* copy on-disk bitmap to buddy
* mark B in on-disk bitmap
* drop PA from group
* mark all PAs in buddy
*
* thus, P1 initializes buddy with B available. to prevent this
* we make "copy" and "mark all PAs" atomic and serialize "drop PA"
* against that pair
*/
ext4_lock_group(sb, grp);
list_del(&pa->pa_group_list);
ext4_unlock_group(sb, grp);
if (pa->pa_type == MB_INODE_PA) {
write_lock(pa->pa_node_lock.inode_lock);
rb_erase(&pa->pa_node.inode_node, &ei->i_prealloc_node);
write_unlock(pa->pa_node_lock.inode_lock);
ext4_mb_pa_free(pa);
} else {
spin_lock(pa->pa_node_lock.lg_lock);
list_del_rcu(&pa->pa_node.lg_list);
spin_unlock(pa->pa_node_lock.lg_lock);
call_rcu(&(pa)->u.pa_rcu, ext4_mb_pa_callback);
}
}
static void ext4_mb_pa_rb_insert(struct rb_root *root, struct rb_node *new)
{
struct rb_node **iter = &root->rb_node, *parent = NULL;
struct ext4_prealloc_space *iter_pa, *new_pa;
ext4_lblk_t iter_start, new_start;
while (*iter) {
iter_pa = rb_entry(*iter, struct ext4_prealloc_space,
pa_node.inode_node);
new_pa = rb_entry(new, struct ext4_prealloc_space,
pa_node.inode_node);
iter_start = iter_pa->pa_lstart;
new_start = new_pa->pa_lstart;
parent = *iter;
if (new_start < iter_start)
iter = &((*iter)->rb_left);
else
iter = &((*iter)->rb_right);
}
rb_link_node(new, parent, iter);
rb_insert_color(new, root);
}
/*
* creates new preallocated space for given inode
*/
static noinline_for_stack void
ext4_mb_new_inode_pa(struct ext4_allocation_context *ac)
{
struct super_block *sb = ac->ac_sb;
struct ext4_sb_info *sbi = EXT4_SB(sb);
struct ext4_prealloc_space *pa;
struct ext4_group_info *grp;
struct ext4_inode_info *ei;
/* preallocate only when found space is larger then requested */
BUG_ON(ac->ac_o_ex.fe_len >= ac->ac_b_ex.fe_len);
BUG_ON(ac->ac_status != AC_STATUS_FOUND);
BUG_ON(!S_ISREG(ac->ac_inode->i_mode));
BUG_ON(ac->ac_pa == NULL);
pa = ac->ac_pa;
if (ac->ac_b_ex.fe_len < ac->ac_orig_goal_len) {
int new_bex_start;
int new_bex_end;
/* we can't allocate as much as normalizer wants.
* so, found space must get proper lstart
* to cover original request */
BUG_ON(ac->ac_g_ex.fe_logical > ac->ac_o_ex.fe_logical);
BUG_ON(ac->ac_g_ex.fe_len < ac->ac_o_ex.fe_len);
/*
* Use the below logic for adjusting best extent as it keeps
* fragmentation in check while ensuring logical range of best
* extent doesn't overflow out of goal extent:
*
* 1. Check if best ex can be kept at end of goal (before
* cr_best_avail trimmed it) and still cover original start
* 2. Else, check if best ex can be kept at start of goal and
* still cover original start
* 3. Else, keep the best ex at start of original request.
*/
new_bex_end = ac->ac_g_ex.fe_logical +
EXT4_C2B(sbi, ac->ac_orig_goal_len);
new_bex_start = new_bex_end - EXT4_C2B(sbi, ac->ac_b_ex.fe_len);
if (ac->ac_o_ex.fe_logical >= new_bex_start)
goto adjust_bex;
new_bex_start = ac->ac_g_ex.fe_logical;
new_bex_end =
new_bex_start + EXT4_C2B(sbi, ac->ac_b_ex.fe_len);
if (ac->ac_o_ex.fe_logical < new_bex_end)
goto adjust_bex;
new_bex_start = ac->ac_o_ex.fe_logical;
new_bex_end =
new_bex_start + EXT4_C2B(sbi, ac->ac_b_ex.fe_len);
adjust_bex:
ac->ac_b_ex.fe_logical = new_bex_start;
BUG_ON(ac->ac_o_ex.fe_logical < ac->ac_b_ex.fe_logical);
BUG_ON(ac->ac_o_ex.fe_len > ac->ac_b_ex.fe_len);
BUG_ON(new_bex_end > (ac->ac_g_ex.fe_logical +
EXT4_C2B(sbi, ac->ac_orig_goal_len)));
}
pa->pa_lstart = ac->ac_b_ex.fe_logical;
pa->pa_pstart = ext4_grp_offs_to_block(sb, &ac->ac_b_ex);
pa->pa_len = ac->ac_b_ex.fe_len;
pa->pa_free = pa->pa_len;
spin_lock_init(&pa->pa_lock);
INIT_LIST_HEAD(&pa->pa_group_list);
pa->pa_deleted = 0;
pa->pa_type = MB_INODE_PA;
mb_debug(sb, "new inode pa %p: %llu/%d for %u\n", pa, pa->pa_pstart,
pa->pa_len, pa->pa_lstart);
trace_ext4_mb_new_inode_pa(ac, pa);
atomic_add(pa->pa_free, &sbi->s_mb_preallocated);
ext4_mb_use_inode_pa(ac, pa);
ei = EXT4_I(ac->ac_inode);
grp = ext4_get_group_info(sb, ac->ac_b_ex.fe_group);
if (!grp)
return;
pa->pa_node_lock.inode_lock = &ei->i_prealloc_lock;
pa->pa_inode = ac->ac_inode;
list_add(&pa->pa_group_list, &grp->bb_prealloc_list);
write_lock(pa->pa_node_lock.inode_lock);
ext4_mb_pa_rb_insert(&ei->i_prealloc_node, &pa->pa_node.inode_node);
write_unlock(pa->pa_node_lock.inode_lock);
atomic_inc(&ei->i_prealloc_active);
}
/*
* creates new preallocated space for locality group inodes belongs to
*/
static noinline_for_stack void
ext4_mb_new_group_pa(struct ext4_allocation_context *ac)
{
struct super_block *sb = ac->ac_sb;
struct ext4_locality_group *lg;
struct ext4_prealloc_space *pa;
struct ext4_group_info *grp;
/* preallocate only when found space is larger then requested */
BUG_ON(ac->ac_o_ex.fe_len >= ac->ac_b_ex.fe_len);
BUG_ON(ac->ac_status != AC_STATUS_FOUND);
BUG_ON(!S_ISREG(ac->ac_inode->i_mode));
BUG_ON(ac->ac_pa == NULL);
pa = ac->ac_pa;
pa->pa_pstart = ext4_grp_offs_to_block(sb, &ac->ac_b_ex);
pa->pa_lstart = pa->pa_pstart;
pa->pa_len = ac->ac_b_ex.fe_len;
pa->pa_free = pa->pa_len;
spin_lock_init(&pa->pa_lock);
INIT_LIST_HEAD(&pa->pa_node.lg_list);
INIT_LIST_HEAD(&pa->pa_group_list);
pa->pa_deleted = 0;
pa->pa_type = MB_GROUP_PA;
mb_debug(sb, "new group pa %p: %llu/%d for %u\n", pa, pa->pa_pstart,
pa->pa_len, pa->pa_lstart);
trace_ext4_mb_new_group_pa(ac, pa);
ext4_mb_use_group_pa(ac, pa);
atomic_add(pa->pa_free, &EXT4_SB(sb)->s_mb_preallocated);
grp = ext4_get_group_info(sb, ac->ac_b_ex.fe_group);
if (!grp)
return;
lg = ac->ac_lg;
BUG_ON(lg == NULL);
pa->pa_node_lock.lg_lock = &lg->lg_prealloc_lock;
pa->pa_inode = NULL;
list_add(&pa->pa_group_list, &grp->bb_prealloc_list);
/*
* We will later add the new pa to the right bucket
* after updating the pa_free in ext4_mb_release_context
*/
}
static void ext4_mb_new_preallocation(struct ext4_allocation_context *ac)
{
if (ac->ac_flags & EXT4_MB_HINT_GROUP_ALLOC)
ext4_mb_new_group_pa(ac);
else
ext4_mb_new_inode_pa(ac);
}
/*
* finds all unused blocks in on-disk bitmap, frees them in
* in-core bitmap and buddy.
* @pa must be unlinked from inode and group lists, so that
* nobody else can find/use it.
* the caller MUST hold group/inode locks.
* TODO: optimize the case when there are no in-core structures yet
*/
static noinline_for_stack int
ext4_mb_release_inode_pa(struct ext4_buddy *e4b, struct buffer_head *bitmap_bh,
struct ext4_prealloc_space *pa)
{
struct super_block *sb = e4b->bd_sb;
struct ext4_sb_info *sbi = EXT4_SB(sb);
unsigned int end;
unsigned int next;
ext4_group_t group;
ext4_grpblk_t bit;
unsigned long long grp_blk_start;
int free = 0;
BUG_ON(pa->pa_deleted == 0);
ext4_get_group_no_and_offset(sb, pa->pa_pstart, &group, &bit);
grp_blk_start = pa->pa_pstart - EXT4_C2B(sbi, bit);
BUG_ON(group != e4b->bd_group && pa->pa_len != 0);
end = bit + pa->pa_len;
while (bit < end) {
bit = mb_find_next_zero_bit(bitmap_bh->b_data, end, bit);
if (bit >= end)
break;
next = mb_find_next_bit(bitmap_bh->b_data, end, bit);
mb_debug(sb, "free preallocated %u/%u in group %u\n",
(unsigned) ext4_group_first_block_no(sb, group) + bit,
(unsigned) next - bit, (unsigned) group);
free += next - bit;
trace_ext4_mballoc_discard(sb, NULL, group, bit, next - bit);
trace_ext4_mb_release_inode_pa(pa, (grp_blk_start +
EXT4_C2B(sbi, bit)),
next - bit);
mb_free_blocks(pa->pa_inode, e4b, bit, next - bit);
bit = next + 1;
}
if (free != pa->pa_free) {
ext4_msg(e4b->bd_sb, KERN_CRIT,
"pa %p: logic %lu, phys. %lu, len %d",
pa, (unsigned long) pa->pa_lstart,
(unsigned long) pa->pa_pstart,
pa->pa_len);
ext4_grp_locked_error(sb, group, 0, 0, "free %u, pa_free %u",
free, pa->pa_free);
/*
* pa is already deleted so we use the value obtained
* from the bitmap and continue.
*/
}
atomic_add(free, &sbi->s_mb_discarded);
return 0;
}
static noinline_for_stack int
ext4_mb_release_group_pa(struct ext4_buddy *e4b,
struct ext4_prealloc_space *pa)
{
struct super_block *sb = e4b->bd_sb;
ext4_group_t group;
ext4_grpblk_t bit;
trace_ext4_mb_release_group_pa(sb, pa);
BUG_ON(pa->pa_deleted == 0);
ext4_get_group_no_and_offset(sb, pa->pa_pstart, &group, &bit);
if (unlikely(group != e4b->bd_group && pa->pa_len != 0)) {
ext4_warning(sb, "bad group: expected %u, group %u, pa_start %llu",
e4b->bd_group, group, pa->pa_pstart);
return 0;
}
mb_free_blocks(pa->pa_inode, e4b, bit, pa->pa_len);
atomic_add(pa->pa_len, &EXT4_SB(sb)->s_mb_discarded);
trace_ext4_mballoc_discard(sb, NULL, group, bit, pa->pa_len);
return 0;
}
/*
* releases all preallocations in given group
*
* first, we need to decide discard policy:
* - when do we discard
* 1) ENOSPC
* - how many do we discard
* 1) how many requested
*/
static noinline_for_stack int
ext4_mb_discard_group_preallocations(struct super_block *sb,
ext4_group_t group, int *busy)
{
struct ext4_group_info *grp = ext4_get_group_info(sb, group);
struct buffer_head *bitmap_bh = NULL;
struct ext4_prealloc_space *pa, *tmp;
struct list_head list;
struct ext4_buddy e4b;
struct ext4_inode_info *ei;
int err;
int free = 0;
if (!grp)
return 0;
mb_debug(sb, "discard preallocation for group %u\n", group);
if (list_empty(&grp->bb_prealloc_list))
goto out_dbg;
bitmap_bh = ext4_read_block_bitmap(sb, group);
if (IS_ERR(bitmap_bh)) {
err = PTR_ERR(bitmap_bh);
ext4_error_err(sb, -err,
"Error %d reading block bitmap for %u",
err, group);
goto out_dbg;
}
err = ext4_mb_load_buddy(sb, group, &e4b);
if (err) {
ext4_warning(sb, "Error %d loading buddy information for %u",
err, group);
put_bh(bitmap_bh);
goto out_dbg;
}
INIT_LIST_HEAD(&list);
ext4_lock_group(sb, group);
list_for_each_entry_safe(pa, tmp,
&grp->bb_prealloc_list, pa_group_list) {
spin_lock(&pa->pa_lock);
if (atomic_read(&pa->pa_count)) {
spin_unlock(&pa->pa_lock);
*busy = 1;
continue;
}
if (pa->pa_deleted) {
spin_unlock(&pa->pa_lock);
continue;
}
/* seems this one can be freed ... */
ext4_mb_mark_pa_deleted(sb, pa);
if (!free)
this_cpu_inc(discard_pa_seq);
/* we can trust pa_free ... */
free += pa->pa_free;
spin_unlock(&pa->pa_lock);
list_del(&pa->pa_group_list);
list_add(&pa->u.pa_tmp_list, &list);
}
/* now free all selected PAs */
list_for_each_entry_safe(pa, tmp, &list, u.pa_tmp_list) {
/* remove from object (inode or locality group) */
if (pa->pa_type == MB_GROUP_PA) {
spin_lock(pa->pa_node_lock.lg_lock);
list_del_rcu(&pa->pa_node.lg_list);
spin_unlock(pa->pa_node_lock.lg_lock);
} else {
write_lock(pa->pa_node_lock.inode_lock);
ei = EXT4_I(pa->pa_inode);
rb_erase(&pa->pa_node.inode_node, &ei->i_prealloc_node);
write_unlock(pa->pa_node_lock.inode_lock);
}
list_del(&pa->u.pa_tmp_list);
if (pa->pa_type == MB_GROUP_PA) {
ext4_mb_release_group_pa(&e4b, pa);
call_rcu(&(pa)->u.pa_rcu, ext4_mb_pa_callback);
} else {
ext4_mb_release_inode_pa(&e4b, bitmap_bh, pa);
ext4_mb_pa_free(pa);
}
}
ext4_unlock_group(sb, group);
ext4_mb_unload_buddy(&e4b);
put_bh(bitmap_bh);
out_dbg:
mb_debug(sb, "discarded (%d) blocks preallocated for group %u bb_free (%d)\n",
free, group, grp->bb_free);
return free;
}
/*
* releases all non-used preallocated blocks for given inode
*
* It's important to discard preallocations under i_data_sem
* We don't want another block to be served from the prealloc
* space when we are discarding the inode prealloc space.
*
* FIXME!! Make sure it is valid at all the call sites
*/
void ext4_discard_preallocations(struct inode *inode, unsigned int needed)
{
struct ext4_inode_info *ei = EXT4_I(inode);
struct super_block *sb = inode->i_sb;
struct buffer_head *bitmap_bh = NULL;
struct ext4_prealloc_space *pa, *tmp;
ext4_group_t group = 0;
struct list_head list;
struct ext4_buddy e4b;
struct rb_node *iter;
int err;
if (!S_ISREG(inode->i_mode)) {
return;
}
if (EXT4_SB(sb)->s_mount_state & EXT4_FC_REPLAY)
return;
mb_debug(sb, "discard preallocation for inode %lu\n",
inode->i_ino);
trace_ext4_discard_preallocations(inode,
atomic_read(&ei->i_prealloc_active), needed);
INIT_LIST_HEAD(&list);
if (needed == 0)
needed = UINT_MAX;
repeat:
/* first, collect all pa's in the inode */
write_lock(&ei->i_prealloc_lock);
for (iter = rb_first(&ei->i_prealloc_node); iter && needed;
iter = rb_next(iter)) {
pa = rb_entry(iter, struct ext4_prealloc_space,
pa_node.inode_node);
BUG_ON(pa->pa_node_lock.inode_lock != &ei->i_prealloc_lock);
spin_lock(&pa->pa_lock);
if (atomic_read(&pa->pa_count)) {
/* this shouldn't happen often - nobody should
* use preallocation while we're discarding it */
spin_unlock(&pa->pa_lock);
write_unlock(&ei->i_prealloc_lock);
ext4_msg(sb, KERN_ERR,
"uh-oh! used pa while discarding");
WARN_ON(1);
schedule_timeout_uninterruptible(HZ);
goto repeat;
}
if (pa->pa_deleted == 0) {
ext4_mb_mark_pa_deleted(sb, pa);
spin_unlock(&pa->pa_lock);
rb_erase(&pa->pa_node.inode_node, &ei->i_prealloc_node);
list_add(&pa->u.pa_tmp_list, &list);
needed--;
continue;
}
/* someone is deleting pa right now */
spin_unlock(&pa->pa_lock);
write_unlock(&ei->i_prealloc_lock);
/* we have to wait here because pa_deleted
* doesn't mean pa is already unlinked from
* the list. as we might be called from
* ->clear_inode() the inode will get freed
* and concurrent thread which is unlinking
* pa from inode's list may access already
* freed memory, bad-bad-bad */
/* XXX: if this happens too often, we can
* add a flag to force wait only in case
* of ->clear_inode(), but not in case of
* regular truncate */
schedule_timeout_uninterruptible(HZ);
goto repeat;
}
write_unlock(&ei->i_prealloc_lock);
list_for_each_entry_safe(pa, tmp, &list, u.pa_tmp_list) {
BUG_ON(pa->pa_type != MB_INODE_PA);
group = ext4_get_group_number(sb, pa->pa_pstart);
err = ext4_mb_load_buddy_gfp(sb, group, &e4b,
GFP_NOFS|__GFP_NOFAIL);
if (err) {
ext4_error_err(sb, -err, "Error %d loading buddy information for %u",
err, group);
continue;
}
bitmap_bh = ext4_read_block_bitmap(sb, group);
if (IS_ERR(bitmap_bh)) {
err = PTR_ERR(bitmap_bh);
ext4_error_err(sb, -err, "Error %d reading block bitmap for %u",
err, group);
ext4_mb_unload_buddy(&e4b);
continue;
}
ext4_lock_group(sb, group);
list_del(&pa->pa_group_list);
ext4_mb_release_inode_pa(&e4b, bitmap_bh, pa);
ext4_unlock_group(sb, group);
ext4_mb_unload_buddy(&e4b);
put_bh(bitmap_bh);
list_del(&pa->u.pa_tmp_list);
ext4_mb_pa_free(pa);
}
}
static int ext4_mb_pa_alloc(struct ext4_allocation_context *ac)
{
struct ext4_prealloc_space *pa;
BUG_ON(ext4_pspace_cachep == NULL);
pa = kmem_cache_zalloc(ext4_pspace_cachep, GFP_NOFS);
if (!pa)
return -ENOMEM;
atomic_set(&pa->pa_count, 1);
ac->ac_pa = pa;
return 0;
}
static void ext4_mb_pa_put_free(struct ext4_allocation_context *ac)
{
struct ext4_prealloc_space *pa = ac->ac_pa;
BUG_ON(!pa);
ac->ac_pa = NULL;
WARN_ON(!atomic_dec_and_test(&pa->pa_count));
/*
* current function is only called due to an error or due to
* len of found blocks < len of requested blocks hence the PA has not
* been added to grp->bb_prealloc_list. So we don't need to lock it
*/
pa->pa_deleted = 1;
ext4_mb_pa_free(pa);
}
#ifdef CONFIG_EXT4_DEBUG
static inline void ext4_mb_show_pa(struct super_block *sb)
{
ext4_group_t i, ngroups;
if (ext4_test_mount_flag(sb, EXT4_MF_FS_ABORTED))
return;
ngroups = ext4_get_groups_count(sb);
mb_debug(sb, "groups: ");
for (i = 0; i < ngroups; i++) {
struct ext4_group_info *grp = ext4_get_group_info(sb, i);
struct ext4_prealloc_space *pa;
ext4_grpblk_t start;
struct list_head *cur;
if (!grp)
continue;
ext4_lock_group(sb, i);
list_for_each(cur, &grp->bb_prealloc_list) {
pa = list_entry(cur, struct ext4_prealloc_space,
pa_group_list);
spin_lock(&pa->pa_lock);
ext4_get_group_no_and_offset(sb, pa->pa_pstart,
NULL, &start);
spin_unlock(&pa->pa_lock);
mb_debug(sb, "PA:%u:%d:%d\n", i, start,
pa->pa_len);
}
ext4_unlock_group(sb, i);
mb_debug(sb, "%u: %d/%d\n", i, grp->bb_free,
grp->bb_fragments);
}
}
static void ext4_mb_show_ac(struct ext4_allocation_context *ac)
{
struct super_block *sb = ac->ac_sb;
if (ext4_test_mount_flag(sb, EXT4_MF_FS_ABORTED))
return;
mb_debug(sb, "Can't allocate:"
" Allocation context details:");
mb_debug(sb, "status %u flags 0x%x",
ac->ac_status, ac->ac_flags);
mb_debug(sb, "orig %lu/%lu/%lu@%lu, "
"goal %lu/%lu/%lu@%lu, "
"best %lu/%lu/%lu@%lu cr %d",
(unsigned long)ac->ac_o_ex.fe_group,
(unsigned long)ac->ac_o_ex.fe_start,
(unsigned long)ac->ac_o_ex.fe_len,
(unsigned long)ac->ac_o_ex.fe_logical,
(unsigned long)ac->ac_g_ex.fe_group,
(unsigned long)ac->ac_g_ex.fe_start,
(unsigned long)ac->ac_g_ex.fe_len,
(unsigned long)ac->ac_g_ex.fe_logical,
(unsigned long)ac->ac_b_ex.fe_group,
(unsigned long)ac->ac_b_ex.fe_start,
(unsigned long)ac->ac_b_ex.fe_len,
(unsigned long)ac->ac_b_ex.fe_logical,
(int)ac->ac_criteria);
mb_debug(sb, "%u found", ac->ac_found);
mb_debug(sb, "used pa: %s, ", ac->ac_pa ? "yes" : "no");
if (ac->ac_pa)
mb_debug(sb, "pa_type %s\n", ac->ac_pa->pa_type == MB_GROUP_PA ?
"group pa" : "inode pa");
ext4_mb_show_pa(sb);
}
#else
static inline void ext4_mb_show_pa(struct super_block *sb)
{
return;
}
static inline void ext4_mb_show_ac(struct ext4_allocation_context *ac)
{
ext4_mb_show_pa(ac->ac_sb);
return;
}
#endif
/*
* We use locality group preallocation for small size file. The size of the
* file is determined by the current size or the resulting size after
* allocation which ever is larger
*
* One can tune this size via /sys/fs/ext4/<partition>/mb_stream_req
*/
static void ext4_mb_group_or_file(struct ext4_allocation_context *ac)
{
struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
int bsbits = ac->ac_sb->s_blocksize_bits;
loff_t size, isize;
bool inode_pa_eligible, group_pa_eligible;
if (!(ac->ac_flags & EXT4_MB_HINT_DATA))
return;
if (unlikely(ac->ac_flags & EXT4_MB_HINT_GOAL_ONLY))
return;
group_pa_eligible = sbi->s_mb_group_prealloc > 0;
inode_pa_eligible = true;
size = ac->ac_o_ex.fe_logical + EXT4_C2B(sbi, ac->ac_o_ex.fe_len);
isize = (i_size_read(ac->ac_inode) + ac->ac_sb->s_blocksize - 1)
>> bsbits;
/* No point in using inode preallocation for closed files */
if ((size == isize) && !ext4_fs_is_busy(sbi) &&
!inode_is_open_for_write(ac->ac_inode))
inode_pa_eligible = false;
size = max(size, isize);
/* Don't use group allocation for large files */
if (size > sbi->s_mb_stream_request)
group_pa_eligible = false;
if (!group_pa_eligible) {
if (inode_pa_eligible)
ac->ac_flags |= EXT4_MB_STREAM_ALLOC;
else
ac->ac_flags |= EXT4_MB_HINT_NOPREALLOC;
return;
}
BUG_ON(ac->ac_lg != NULL);
/*
* locality group prealloc space are per cpu. The reason for having
* per cpu locality group is to reduce the contention between block
* request from multiple CPUs.
*/
ac->ac_lg = raw_cpu_ptr(sbi->s_locality_groups);
/* we're going to use group allocation */
ac->ac_flags |= EXT4_MB_HINT_GROUP_ALLOC;
/* serialize all allocations in the group */
mutex_lock(&ac->ac_lg->lg_mutex);
}
static noinline_for_stack void
ext4_mb_initialize_context(struct ext4_allocation_context *ac,
struct ext4_allocation_request *ar)
{
struct super_block *sb = ar->inode->i_sb;
struct ext4_sb_info *sbi = EXT4_SB(sb);
struct ext4_super_block *es = sbi->s_es;
ext4_group_t group;
unsigned int len;
ext4_fsblk_t goal;
ext4_grpblk_t block;
/* we can't allocate > group size */
len = ar->len;
/* just a dirty hack to filter too big requests */
if (len >= EXT4_CLUSTERS_PER_GROUP(sb))
len = EXT4_CLUSTERS_PER_GROUP(sb);
/* start searching from the goal */
goal = ar->goal;
if (goal < le32_to_cpu(es->s_first_data_block) ||
goal >= ext4_blocks_count(es))
goal = le32_to_cpu(es->s_first_data_block);
ext4_get_group_no_and_offset(sb, goal, &group, &block);
/* set up allocation goals */
ac->ac_b_ex.fe_logical = EXT4_LBLK_CMASK(sbi, ar->logical);
ac->ac_status = AC_STATUS_CONTINUE;
ac->ac_sb = sb;
ac->ac_inode = ar->inode;
ac->ac_o_ex.fe_logical = ac->ac_b_ex.fe_logical;
ac->ac_o_ex.fe_group = group;
ac->ac_o_ex.fe_start = block;
ac->ac_o_ex.fe_len = len;
ac->ac_g_ex = ac->ac_o_ex;
ac->ac_orig_goal_len = ac->ac_g_ex.fe_len;
ac->ac_flags = ar->flags;
/* we have to define context: we'll work with a file or
* locality group. this is a policy, actually */
ext4_mb_group_or_file(ac);
mb_debug(sb, "init ac: %u blocks @ %u, goal %u, flags 0x%x, 2^%d, "
"left: %u/%u, right %u/%u to %swritable\n",
(unsigned) ar->len, (unsigned) ar->logical,
(unsigned) ar->goal, ac->ac_flags, ac->ac_2order,
(unsigned) ar->lleft, (unsigned) ar->pleft,
(unsigned) ar->lright, (unsigned) ar->pright,
inode_is_open_for_write(ar->inode) ? "" : "non-");
}
static noinline_for_stack void
ext4_mb_discard_lg_preallocations(struct super_block *sb,
struct ext4_locality_group *lg,
int order, int total_entries)
{
ext4_group_t group = 0;
struct ext4_buddy e4b;
struct list_head discard_list;
struct ext4_prealloc_space *pa, *tmp;
mb_debug(sb, "discard locality group preallocation\n");
INIT_LIST_HEAD(&discard_list);
spin_lock(&lg->lg_prealloc_lock);
list_for_each_entry_rcu(pa, &lg->lg_prealloc_list[order],
pa_node.lg_list,
lockdep_is_held(&lg->lg_prealloc_lock)) {
spin_lock(&pa->pa_lock);
if (atomic_read(&pa->pa_count)) {
/*
* This is the pa that we just used
* for block allocation. So don't
* free that
*/
spin_unlock(&pa->pa_lock);
continue;
}
if (pa->pa_deleted) {
spin_unlock(&pa->pa_lock);
continue;
}
/* only lg prealloc space */
BUG_ON(pa->pa_type != MB_GROUP_PA);
/* seems this one can be freed ... */
ext4_mb_mark_pa_deleted(sb, pa);
spin_unlock(&pa->pa_lock);
list_del_rcu(&pa->pa_node.lg_list);
list_add(&pa->u.pa_tmp_list, &discard_list);
total_entries--;
if (total_entries <= 5) {
/*
* we want to keep only 5 entries
* allowing it to grow to 8. This
* mak sure we don't call discard
* soon for this list.
*/
break;
}
}
spin_unlock(&lg->lg_prealloc_lock);
list_for_each_entry_safe(pa, tmp, &discard_list, u.pa_tmp_list) {
int err;
group = ext4_get_group_number(sb, pa->pa_pstart);
err = ext4_mb_load_buddy_gfp(sb, group, &e4b,
GFP_NOFS|__GFP_NOFAIL);
if (err) {
ext4_error_err(sb, -err, "Error %d loading buddy information for %u",
err, group);
continue;
}
ext4_lock_group(sb, group);
list_del(&pa->pa_group_list);
ext4_mb_release_group_pa(&e4b, pa);
ext4_unlock_group(sb, group);
ext4_mb_unload_buddy(&e4b);
list_del(&pa->u.pa_tmp_list);
call_rcu(&(pa)->u.pa_rcu, ext4_mb_pa_callback);
}
}
/*
* We have incremented pa_count. So it cannot be freed at this
* point. Also we hold lg_mutex. So no parallel allocation is
* possible from this lg. That means pa_free cannot be updated.
*
* A parallel ext4_mb_discard_group_preallocations is possible.
* which can cause the lg_prealloc_list to be updated.
*/
static void ext4_mb_add_n_trim(struct ext4_allocation_context *ac)
{
int order, added = 0, lg_prealloc_count = 1;
struct super_block *sb = ac->ac_sb;
struct ext4_locality_group *lg = ac->ac_lg;
struct ext4_prealloc_space *tmp_pa, *pa = ac->ac_pa;
order = fls(pa->pa_free) - 1;
if (order > PREALLOC_TB_SIZE - 1)
/* The max size of hash table is PREALLOC_TB_SIZE */
order = PREALLOC_TB_SIZE - 1;
/* Add the prealloc space to lg */
spin_lock(&lg->lg_prealloc_lock);
list_for_each_entry_rcu(tmp_pa, &lg->lg_prealloc_list[order],
pa_node.lg_list,
lockdep_is_held(&lg->lg_prealloc_lock)) {
spin_lock(&tmp_pa->pa_lock);
if (tmp_pa->pa_deleted) {
spin_unlock(&tmp_pa->pa_lock);
continue;
}
if (!added && pa->pa_free < tmp_pa->pa_free) {
/* Add to the tail of the previous entry */
list_add_tail_rcu(&pa->pa_node.lg_list,
&tmp_pa->pa_node.lg_list);
added = 1;
/*
* we want to count the total
* number of entries in the list
*/
}
spin_unlock(&tmp_pa->pa_lock);
lg_prealloc_count++;
}
if (!added)
list_add_tail_rcu(&pa->pa_node.lg_list,
&lg->lg_prealloc_list[order]);
spin_unlock(&lg->lg_prealloc_lock);
/* Now trim the list to be not more than 8 elements */
if (lg_prealloc_count > 8) {
ext4_mb_discard_lg_preallocations(sb, lg,
order, lg_prealloc_count);
return;
}
return ;
}
/*
* release all resource we used in allocation
*/
static int ext4_mb_release_context(struct ext4_allocation_context *ac)
{
struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
struct ext4_prealloc_space *pa = ac->ac_pa;
if (pa) {
if (pa->pa_type == MB_GROUP_PA) {
/* see comment in ext4_mb_use_group_pa() */
spin_lock(&pa->pa_lock);
pa->pa_pstart += EXT4_C2B(sbi, ac->ac_b_ex.fe_len);
pa->pa_lstart += EXT4_C2B(sbi, ac->ac_b_ex.fe_len);
pa->pa_free -= ac->ac_b_ex.fe_len;
pa->pa_len -= ac->ac_b_ex.fe_len;
spin_unlock(&pa->pa_lock);
/*
* We want to add the pa to the right bucket.
* Remove it from the list and while adding
* make sure the list to which we are adding
* doesn't grow big.
*/
if (likely(pa->pa_free)) {
spin_lock(pa->pa_node_lock.lg_lock);
list_del_rcu(&pa->pa_node.lg_list);
spin_unlock(pa->pa_node_lock.lg_lock);
ext4_mb_add_n_trim(ac);
}
}
ext4_mb_put_pa(ac, ac->ac_sb, pa);
}
if (ac->ac_bitmap_page)
put_page(ac->ac_bitmap_page);
if (ac->ac_buddy_page)
put_page(ac->ac_buddy_page);
if (ac->ac_flags & EXT4_MB_HINT_GROUP_ALLOC)
mutex_unlock(&ac->ac_lg->lg_mutex);
ext4_mb_collect_stats(ac);
return 0;
}
static int ext4_mb_discard_preallocations(struct super_block *sb, int needed)
{
ext4_group_t i, ngroups = ext4_get_groups_count(sb);
int ret;
int freed = 0, busy = 0;
int retry = 0;
trace_ext4_mb_discard_preallocations(sb, needed);
if (needed == 0)
needed = EXT4_CLUSTERS_PER_GROUP(sb) + 1;
repeat:
for (i = 0; i < ngroups && needed > 0; i++) {
ret = ext4_mb_discard_group_preallocations(sb, i, &busy);
freed += ret;
needed -= ret;
cond_resched();
}
if (needed > 0 && busy && ++retry < 3) {
busy = 0;
goto repeat;
}
return freed;
}
static bool ext4_mb_discard_preallocations_should_retry(struct super_block *sb,
struct ext4_allocation_context *ac, u64 *seq)
{
int freed;
u64 seq_retry = 0;
bool ret = false;
freed = ext4_mb_discard_preallocations(sb, ac->ac_o_ex.fe_len);
if (freed) {
ret = true;
goto out_dbg;
}
seq_retry = ext4_get_discard_pa_seq_sum();
if (!(ac->ac_flags & EXT4_MB_STRICT_CHECK) || seq_retry != *seq) {
ac->ac_flags |= EXT4_MB_STRICT_CHECK;
*seq = seq_retry;
ret = true;
}
out_dbg:
mb_debug(sb, "freed %d, retry ? %s\n", freed, ret ? "yes" : "no");
return ret;
}
/*
* Simple allocator for Ext4 fast commit replay path. It searches for blocks
* linearly starting at the goal block and also excludes the blocks which
* are going to be in use after fast commit replay.
*/
static ext4_fsblk_t
ext4_mb_new_blocks_simple(struct ext4_allocation_request *ar, int *errp)
{
struct buffer_head *bitmap_bh;
struct super_block *sb = ar->inode->i_sb;
struct ext4_sb_info *sbi = EXT4_SB(sb);
ext4_group_t group, nr;
ext4_grpblk_t blkoff;
ext4_grpblk_t max = EXT4_CLUSTERS_PER_GROUP(sb);
ext4_grpblk_t i = 0;
ext4_fsblk_t goal, block;
struct ext4_super_block *es = EXT4_SB(sb)->s_es;
goal = ar->goal;
if (goal < le32_to_cpu(es->s_first_data_block) ||
goal >= ext4_blocks_count(es))
goal = le32_to_cpu(es->s_first_data_block);
ar->len = 0;
ext4_get_group_no_and_offset(sb, goal, &group, &blkoff);
for (nr = ext4_get_groups_count(sb); nr > 0; nr--) {
bitmap_bh = ext4_read_block_bitmap(sb, group);
if (IS_ERR(bitmap_bh)) {
*errp = PTR_ERR(bitmap_bh);
pr_warn("Failed to read block bitmap\n");
return 0;
}
while (1) {
i = mb_find_next_zero_bit(bitmap_bh->b_data, max,
blkoff);
if (i >= max)
break;
if (ext4_fc_replay_check_excluded(sb,
ext4_group_first_block_no(sb, group) +
EXT4_C2B(sbi, i))) {
blkoff = i + 1;
} else
break;
}
brelse(bitmap_bh);
if (i < max)
break;
if (++group >= ext4_get_groups_count(sb))
group = 0;
blkoff = 0;
}
if (i >= max) {
*errp = -ENOSPC;
return 0;
}
block = ext4_group_first_block_no(sb, group) + EXT4_C2B(sbi, i);
ext4_mb_mark_bb(sb, block, 1, 1);
ar->len = 1;
return block;
}
/*
* Main entry point into mballoc to allocate blocks
* it tries to use preallocation first, then falls back
* to usual allocation
*/
ext4_fsblk_t ext4_mb_new_blocks(handle_t *handle,
struct ext4_allocation_request *ar, int *errp)
{
struct ext4_allocation_context *ac = NULL;
struct ext4_sb_info *sbi;
struct super_block *sb;
ext4_fsblk_t block = 0;
unsigned int inquota = 0;
unsigned int reserv_clstrs = 0;
int retries = 0;
u64 seq;
might_sleep();
sb = ar->inode->i_sb;
sbi = EXT4_SB(sb);
trace_ext4_request_blocks(ar);
if (sbi->s_mount_state & EXT4_FC_REPLAY)
return ext4_mb_new_blocks_simple(ar, errp);
/* Allow to use superuser reservation for quota file */
if (ext4_is_quota_file(ar->inode))
ar->flags |= EXT4_MB_USE_ROOT_BLOCKS;
if ((ar->flags & EXT4_MB_DELALLOC_RESERVED) == 0) {
/* Without delayed allocation we need to verify
* there is enough free blocks to do block allocation
* and verify allocation doesn't exceed the quota limits.
*/
while (ar->len &&
ext4_claim_free_clusters(sbi, ar->len, ar->flags)) {
/* let others to free the space */
cond_resched();
ar->len = ar->len >> 1;
}
if (!ar->len) {
ext4_mb_show_pa(sb);
*errp = -ENOSPC;
return 0;
}
reserv_clstrs = ar->len;
if (ar->flags & EXT4_MB_USE_ROOT_BLOCKS) {
dquot_alloc_block_nofail(ar->inode,
EXT4_C2B(sbi, ar->len));
} else {
while (ar->len &&
dquot_alloc_block(ar->inode,
EXT4_C2B(sbi, ar->len))) {
ar->flags |= EXT4_MB_HINT_NOPREALLOC;
ar->len--;
}
}
inquota = ar->len;
if (ar->len == 0) {
*errp = -EDQUOT;
goto out;
}
}
ac = kmem_cache_zalloc(ext4_ac_cachep, GFP_NOFS);
if (!ac) {
ar->len = 0;
*errp = -ENOMEM;
goto out;
}
ext4_mb_initialize_context(ac, ar);
ac->ac_op = EXT4_MB_HISTORY_PREALLOC;
seq = this_cpu_read(discard_pa_seq);
if (!ext4_mb_use_preallocated(ac)) {
ac->ac_op = EXT4_MB_HISTORY_ALLOC;
ext4_mb_normalize_request(ac, ar);
*errp = ext4_mb_pa_alloc(ac);
if (*errp)
goto errout;
repeat:
/* allocate space in core */
*errp = ext4_mb_regular_allocator(ac);
/*
* pa allocated above is added to grp->bb_prealloc_list only
* when we were able to allocate some block i.e. when
* ac->ac_status == AC_STATUS_FOUND.
* And error from above mean ac->ac_status != AC_STATUS_FOUND
* So we have to free this pa here itself.
*/
if (*errp) {
ext4_mb_pa_put_free(ac);
ext4_discard_allocated_blocks(ac);
goto errout;
}
if (ac->ac_status == AC_STATUS_FOUND &&
ac->ac_o_ex.fe_len >= ac->ac_f_ex.fe_len)
ext4_mb_pa_put_free(ac);
}
if (likely(ac->ac_status == AC_STATUS_FOUND)) {
*errp = ext4_mb_mark_diskspace_used(ac, handle, reserv_clstrs);
if (*errp) {
ext4_discard_allocated_blocks(ac);
goto errout;
} else {
block = ext4_grp_offs_to_block(sb, &ac->ac_b_ex);
ar->len = ac->ac_b_ex.fe_len;
}
} else {
if (++retries < 3 &&
ext4_mb_discard_preallocations_should_retry(sb, ac, &seq))
goto repeat;
/*
* If block allocation fails then the pa allocated above
* needs to be freed here itself.
*/
ext4_mb_pa_put_free(ac);
*errp = -ENOSPC;
}
if (*errp) {
errout:
ac->ac_b_ex.fe_len = 0;
ar->len = 0;
ext4_mb_show_ac(ac);
}
ext4_mb_release_context(ac);
kmem_cache_free(ext4_ac_cachep, ac);
out:
if (inquota && ar->len < inquota)
dquot_free_block(ar->inode, EXT4_C2B(sbi, inquota - ar->len));
if (!ar->len) {
if ((ar->flags & EXT4_MB_DELALLOC_RESERVED) == 0)
/* release all the reserved blocks if non delalloc */
percpu_counter_sub(&sbi->s_dirtyclusters_counter,
reserv_clstrs);
}
trace_ext4_allocate_blocks(ar, (unsigned long long)block);
return block;
}
/*
* We can merge two free data extents only if the physical blocks
* are contiguous, AND the extents were freed by the same transaction,
* AND the blocks are associated with the same group.
*/
static void ext4_try_merge_freed_extent(struct ext4_sb_info *sbi,
struct ext4_free_data *entry,
struct ext4_free_data *new_entry,
struct rb_root *entry_rb_root)
{
if ((entry->efd_tid != new_entry->efd_tid) ||
(entry->efd_group != new_entry->efd_group))
return;
if (entry->efd_start_cluster + entry->efd_count ==
new_entry->efd_start_cluster) {
new_entry->efd_start_cluster = entry->efd_start_cluster;
new_entry->efd_count += entry->efd_count;
} else if (new_entry->efd_start_cluster + new_entry->efd_count ==
entry->efd_start_cluster) {
new_entry->efd_count += entry->efd_count;
} else
return;
spin_lock(&sbi->s_md_lock);
list_del(&entry->efd_list);
spin_unlock(&sbi->s_md_lock);
rb_erase(&entry->efd_node, entry_rb_root);
kmem_cache_free(ext4_free_data_cachep, entry);
}
static noinline_for_stack void
ext4_mb_free_metadata(handle_t *handle, struct ext4_buddy *e4b,
struct ext4_free_data *new_entry)
{
ext4_group_t group = e4b->bd_group;
ext4_grpblk_t cluster;
ext4_grpblk_t clusters = new_entry->efd_count;
struct ext4_free_data *entry;
struct ext4_group_info *db = e4b->bd_info;
struct super_block *sb = e4b->bd_sb;
struct ext4_sb_info *sbi = EXT4_SB(sb);
struct rb_node **n = &db->bb_free_root.rb_node, *node;
struct rb_node *parent = NULL, *new_node;
BUG_ON(!ext4_handle_valid(handle));
BUG_ON(e4b->bd_bitmap_page == NULL);
BUG_ON(e4b->bd_buddy_page == NULL);
new_node = &new_entry->efd_node;
cluster = new_entry->efd_start_cluster;
if (!*n) {
/* first free block exent. We need to
protect buddy cache from being freed,
* otherwise we'll refresh it from
* on-disk bitmap and lose not-yet-available
* blocks */
get_page(e4b->bd_buddy_page);
get_page(e4b->bd_bitmap_page);
}
while (*n) {
parent = *n;
entry = rb_entry(parent, struct ext4_free_data, efd_node);
if (cluster < entry->efd_start_cluster)
n = &(*n)->rb_left;
else if (cluster >= (entry->efd_start_cluster + entry->efd_count))
n = &(*n)->rb_right;
else {
ext4_grp_locked_error(sb, group, 0,
ext4_group_first_block_no(sb, group) +
EXT4_C2B(sbi, cluster),
"Block already on to-be-freed list");
kmem_cache_free(ext4_free_data_cachep, new_entry);
return;
}
}
rb_link_node(new_node, parent, n);
rb_insert_color(new_node, &db->bb_free_root);
/* Now try to see the extent can be merged to left and right */
node = rb_prev(new_node);
if (node) {
entry = rb_entry(node, struct ext4_free_data, efd_node);
ext4_try_merge_freed_extent(sbi, entry, new_entry,
&(db->bb_free_root));
}
node = rb_next(new_node);
if (node) {
entry = rb_entry(node, struct ext4_free_data, efd_node);
ext4_try_merge_freed_extent(sbi, entry, new_entry,
&(db->bb_free_root));
}
spin_lock(&sbi->s_md_lock);
list_add_tail(&new_entry->efd_list, &sbi->s_freed_data_list);
sbi->s_mb_free_pending += clusters;
spin_unlock(&sbi->s_md_lock);
}
static void ext4_free_blocks_simple(struct inode *inode, ext4_fsblk_t block,
unsigned long count)
{
struct buffer_head *bitmap_bh;
struct super_block *sb = inode->i_sb;
struct ext4_group_desc *gdp;
struct buffer_head *gdp_bh;
ext4_group_t group;
ext4_grpblk_t blkoff;
int already_freed = 0, err, i;
ext4_get_group_no_and_offset(sb, block, &group, &blkoff);
bitmap_bh = ext4_read_block_bitmap(sb, group);
if (IS_ERR(bitmap_bh)) {
pr_warn("Failed to read block bitmap\n");
return;
}
gdp = ext4_get_group_desc(sb, group, &gdp_bh);
if (!gdp)
goto err_out;
for (i = 0; i < count; i++) {
if (!mb_test_bit(blkoff + i, bitmap_bh->b_data))
already_freed++;
}
mb_clear_bits(bitmap_bh->b_data, blkoff, count);
err = ext4_handle_dirty_metadata(NULL, NULL, bitmap_bh);
if (err)
goto err_out;
ext4_free_group_clusters_set(
sb, gdp, ext4_free_group_clusters(sb, gdp) +
count - already_freed);
ext4_block_bitmap_csum_set(sb, gdp, bitmap_bh);
ext4_group_desc_csum_set(sb, group, gdp);
ext4_handle_dirty_metadata(NULL, NULL, gdp_bh);
sync_dirty_buffer(bitmap_bh);
sync_dirty_buffer(gdp_bh);
err_out:
brelse(bitmap_bh);
}
/**
* ext4_mb_clear_bb() -- helper function for freeing blocks.
* Used by ext4_free_blocks()
* @handle: handle for this transaction
* @inode: inode
* @block: starting physical block to be freed
* @count: number of blocks to be freed
* @flags: flags used by ext4_free_blocks
*/
static void ext4_mb_clear_bb(handle_t *handle, struct inode *inode,
ext4_fsblk_t block, unsigned long count,
int flags)
{
struct buffer_head *bitmap_bh = NULL;
struct super_block *sb = inode->i_sb;
struct ext4_group_desc *gdp;
struct ext4_group_info *grp;
unsigned int overflow;
ext4_grpblk_t bit;
struct buffer_head *gd_bh;
ext4_group_t block_group;
struct ext4_sb_info *sbi;
struct ext4_buddy e4b;
unsigned int count_clusters;
int err = 0;
int ret;
sbi = EXT4_SB(sb);
if (!(flags & EXT4_FREE_BLOCKS_VALIDATED) &&
!ext4_inode_block_valid(inode, block, count)) {
ext4_error(sb, "Freeing blocks in system zone - "
"Block = %llu, count = %lu", block, count);
/* err = 0. ext4_std_error should be a no op */
goto error_return;
}
flags |= EXT4_FREE_BLOCKS_VALIDATED;
do_more:
overflow = 0;
ext4_get_group_no_and_offset(sb, block, &block_group, &bit);
grp = ext4_get_group_info(sb, block_group);
if (unlikely(!grp || EXT4_MB_GRP_BBITMAP_CORRUPT(grp)))
return;
/*
* Check to see if we are freeing blocks across a group
* boundary.
*/
if (EXT4_C2B(sbi, bit) + count > EXT4_BLOCKS_PER_GROUP(sb)) {
overflow = EXT4_C2B(sbi, bit) + count -
EXT4_BLOCKS_PER_GROUP(sb);
count -= overflow;
/* The range changed so it's no longer validated */
flags &= ~EXT4_FREE_BLOCKS_VALIDATED;
}
count_clusters = EXT4_NUM_B2C(sbi, count);
bitmap_bh = ext4_read_block_bitmap(sb, block_group);
if (IS_ERR(bitmap_bh)) {
err = PTR_ERR(bitmap_bh);
bitmap_bh = NULL;
goto error_return;
}
gdp = ext4_get_group_desc(sb, block_group, &gd_bh);
if (!gdp) {
err = -EIO;
goto error_return;
}
if (!(flags & EXT4_FREE_BLOCKS_VALIDATED) &&
!ext4_inode_block_valid(inode, block, count)) {
ext4_error(sb, "Freeing blocks in system zone - "
"Block = %llu, count = %lu", block, count);
/* err = 0. ext4_std_error should be a no op */
goto error_return;
}
BUFFER_TRACE(bitmap_bh, "getting write access");
err = ext4_journal_get_write_access(handle, sb, bitmap_bh,
EXT4_JTR_NONE);
if (err)
goto error_return;
/*
* We are about to modify some metadata. Call the journal APIs
* to unshare ->b_data if a currently-committing transaction is
* using it
*/
BUFFER_TRACE(gd_bh, "get_write_access");
err = ext4_journal_get_write_access(handle, sb, gd_bh, EXT4_JTR_NONE);
if (err)
goto error_return;
#ifdef AGGRESSIVE_CHECK
{
int i;
for (i = 0; i < count_clusters; i++)
BUG_ON(!mb_test_bit(bit + i, bitmap_bh->b_data));
}
#endif
trace_ext4_mballoc_free(sb, inode, block_group, bit, count_clusters);
/* __GFP_NOFAIL: retry infinitely, ignore TIF_MEMDIE and memcg limit. */
err = ext4_mb_load_buddy_gfp(sb, block_group, &e4b,
GFP_NOFS|__GFP_NOFAIL);
if (err)
goto error_return;
/*
* We need to make sure we don't reuse the freed block until after the
* transaction is committed. We make an exception if the inode is to be
* written in writeback mode since writeback mode has weak data
* consistency guarantees.
*/
if (ext4_handle_valid(handle) &&
((flags & EXT4_FREE_BLOCKS_METADATA) ||
!ext4_should_writeback_data(inode))) {
struct ext4_free_data *new_entry;
/*
* We use __GFP_NOFAIL because ext4_free_blocks() is not allowed
* to fail.
*/
new_entry = kmem_cache_alloc(ext4_free_data_cachep,
GFP_NOFS|__GFP_NOFAIL);
new_entry->efd_start_cluster = bit;
new_entry->efd_group = block_group;
new_entry->efd_count = count_clusters;
new_entry->efd_tid = handle->h_transaction->t_tid;
ext4_lock_group(sb, block_group);
mb_clear_bits(bitmap_bh->b_data, bit, count_clusters);
ext4_mb_free_metadata(handle, &e4b, new_entry);
} else {
/* need to update group_info->bb_free and bitmap
* with group lock held. generate_buddy look at
* them with group lock_held
*/
if (test_opt(sb, DISCARD)) {
err = ext4_issue_discard(sb, block_group, bit,
count_clusters, NULL);
if (err && err != -EOPNOTSUPP)
ext4_msg(sb, KERN_WARNING, "discard request in"
" group:%u block:%d count:%lu failed"
" with %d", block_group, bit, count,
err);
} else
EXT4_MB_GRP_CLEAR_TRIMMED(e4b.bd_info);
ext4_lock_group(sb, block_group);
mb_clear_bits(bitmap_bh->b_data, bit, count_clusters);
mb_free_blocks(inode, &e4b, bit, count_clusters);
}
ret = ext4_free_group_clusters(sb, gdp) + count_clusters;
ext4_free_group_clusters_set(sb, gdp, ret);
ext4_block_bitmap_csum_set(sb, gdp, bitmap_bh);
ext4_group_desc_csum_set(sb, block_group, gdp);
ext4_unlock_group(sb, block_group);
if (sbi->s_log_groups_per_flex) {
ext4_group_t flex_group = ext4_flex_group(sbi, block_group);
atomic64_add(count_clusters,
&sbi_array_rcu_deref(sbi, s_flex_groups,
flex_group)->free_clusters);
}
/*
* on a bigalloc file system, defer the s_freeclusters_counter
* update to the caller (ext4_remove_space and friends) so they
* can determine if a cluster freed here should be rereserved
*/
if (!(flags & EXT4_FREE_BLOCKS_RERESERVE_CLUSTER)) {
if (!(flags & EXT4_FREE_BLOCKS_NO_QUOT_UPDATE))
dquot_free_block(inode, EXT4_C2B(sbi, count_clusters));
percpu_counter_add(&sbi->s_freeclusters_counter,
count_clusters);
}
ext4_mb_unload_buddy(&e4b);
/* We dirtied the bitmap block */
BUFFER_TRACE(bitmap_bh, "dirtied bitmap block");
err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh);
/* And the group descriptor block */
BUFFER_TRACE(gd_bh, "dirtied group descriptor block");
ret = ext4_handle_dirty_metadata(handle, NULL, gd_bh);
if (!err)
err = ret;
if (overflow && !err) {
block += count;
count = overflow;
put_bh(bitmap_bh);
/* The range changed so it's no longer validated */
flags &= ~EXT4_FREE_BLOCKS_VALIDATED;
goto do_more;
}
error_return:
brelse(bitmap_bh);
ext4_std_error(sb, err);
return;
}
/**
* ext4_free_blocks() -- Free given blocks and update quota
* @handle: handle for this transaction
* @inode: inode
* @bh: optional buffer of the block to be freed
* @block: starting physical block to be freed
* @count: number of blocks to be freed
* @flags: flags used by ext4_free_blocks
*/
void ext4_free_blocks(handle_t *handle, struct inode *inode,
struct buffer_head *bh, ext4_fsblk_t block,
unsigned long count, int flags)
{
struct super_block *sb = inode->i_sb;
unsigned int overflow;
struct ext4_sb_info *sbi;
sbi = EXT4_SB(sb);
if (bh) {
if (block)
BUG_ON(block != bh->b_blocknr);
else
block = bh->b_blocknr;
}
if (sbi->s_mount_state & EXT4_FC_REPLAY) {
ext4_free_blocks_simple(inode, block, EXT4_NUM_B2C(sbi, count));
return;
}
might_sleep();
if (!(flags & EXT4_FREE_BLOCKS_VALIDATED) &&
!ext4_inode_block_valid(inode, block, count)) {
ext4_error(sb, "Freeing blocks not in datazone - "
"block = %llu, count = %lu", block, count);
return;
}
flags |= EXT4_FREE_BLOCKS_VALIDATED;
ext4_debug("freeing block %llu\n", block);
trace_ext4_free_blocks(inode, block, count, flags);
if (bh && (flags & EXT4_FREE_BLOCKS_FORGET)) {
BUG_ON(count > 1);
ext4_forget(handle, flags & EXT4_FREE_BLOCKS_METADATA,
inode, bh, block);
}
/*
* If the extent to be freed does not begin on a cluster
* boundary, we need to deal with partial clusters at the
* beginning and end of the extent. Normally we will free
* blocks at the beginning or the end unless we are explicitly
* requested to avoid doing so.
*/
overflow = EXT4_PBLK_COFF(sbi, block);
if (overflow) {
if (flags & EXT4_FREE_BLOCKS_NOFREE_FIRST_CLUSTER) {
overflow = sbi->s_cluster_ratio - overflow;
block += overflow;
if (count > overflow)
count -= overflow;
else
return;
} else {
block -= overflow;
count += overflow;
}
/* The range changed so it's no longer validated */
flags &= ~EXT4_FREE_BLOCKS_VALIDATED;
}
overflow = EXT4_LBLK_COFF(sbi, count);
if (overflow) {
if (flags & EXT4_FREE_BLOCKS_NOFREE_LAST_CLUSTER) {
if (count > overflow)
count -= overflow;
else
return;
} else
count += sbi->s_cluster_ratio - overflow;
/* The range changed so it's no longer validated */
flags &= ~EXT4_FREE_BLOCKS_VALIDATED;
}
if (!bh && (flags & EXT4_FREE_BLOCKS_FORGET)) {
int i;
int is_metadata = flags & EXT4_FREE_BLOCKS_METADATA;
for (i = 0; i < count; i++) {
cond_resched();
if (is_metadata)
bh = sb_find_get_block(inode->i_sb, block + i);
ext4_forget(handle, is_metadata, inode, bh, block + i);
}
}
ext4_mb_clear_bb(handle, inode, block, count, flags);
return;
}
/**
* ext4_group_add_blocks() -- Add given blocks to an existing group
* @handle: handle to this transaction
* @sb: super block
* @block: start physical block to add to the block group
* @count: number of blocks to free
*
* This marks the blocks as free in the bitmap and buddy.
*/
int ext4_group_add_blocks(handle_t *handle, struct super_block *sb,
ext4_fsblk_t block, unsigned long count)
{
struct buffer_head *bitmap_bh = NULL;
struct buffer_head *gd_bh;
ext4_group_t block_group;
ext4_grpblk_t bit;
unsigned int i;
struct ext4_group_desc *desc;
struct ext4_sb_info *sbi = EXT4_SB(sb);
struct ext4_buddy e4b;
int err = 0, ret, free_clusters_count;
ext4_grpblk_t clusters_freed;
ext4_fsblk_t first_cluster = EXT4_B2C(sbi, block);
ext4_fsblk_t last_cluster = EXT4_B2C(sbi, block + count - 1);
unsigned long cluster_count = last_cluster - first_cluster + 1;
ext4_debug("Adding block(s) %llu-%llu\n", block, block + count - 1);
if (count == 0)
return 0;
ext4_get_group_no_and_offset(sb, block, &block_group, &bit);
/*
* Check to see if we are freeing blocks across a group
* boundary.
*/
if (bit + cluster_count > EXT4_CLUSTERS_PER_GROUP(sb)) {
ext4_warning(sb, "too many blocks added to group %u",
block_group);
err = -EINVAL;
goto error_return;
}
bitmap_bh = ext4_read_block_bitmap(sb, block_group);
if (IS_ERR(bitmap_bh)) {
err = PTR_ERR(bitmap_bh);
bitmap_bh = NULL;
goto error_return;
}
desc = ext4_get_group_desc(sb, block_group, &gd_bh);
if (!desc) {
err = -EIO;
goto error_return;
}
if (!ext4_sb_block_valid(sb, NULL, block, count)) {
ext4_error(sb, "Adding blocks in system zones - "
"Block = %llu, count = %lu",
block, count);
err = -EINVAL;
goto error_return;
}
BUFFER_TRACE(bitmap_bh, "getting write access");
err = ext4_journal_get_write_access(handle, sb, bitmap_bh,
EXT4_JTR_NONE);
if (err)
goto error_return;
/*
* We are about to modify some metadata. Call the journal APIs
* to unshare ->b_data if a currently-committing transaction is
* using it
*/
BUFFER_TRACE(gd_bh, "get_write_access");
err = ext4_journal_get_write_access(handle, sb, gd_bh, EXT4_JTR_NONE);
if (err)
goto error_return;
for (i = 0, clusters_freed = 0; i < cluster_count; i++) {
BUFFER_TRACE(bitmap_bh, "clear bit");
if (!mb_test_bit(bit + i, bitmap_bh->b_data)) {
ext4_error(sb, "bit already cleared for block %llu",
(ext4_fsblk_t)(block + i));
BUFFER_TRACE(bitmap_bh, "bit already cleared");
} else {
clusters_freed++;
}
}
err = ext4_mb_load_buddy(sb, block_group, &e4b);
if (err)
goto error_return;
/*
* need to update group_info->bb_free and bitmap
* with group lock held. generate_buddy look at
* them with group lock_held
*/
ext4_lock_group(sb, block_group);
mb_clear_bits(bitmap_bh->b_data, bit, cluster_count);
mb_free_blocks(NULL, &e4b, bit, cluster_count);
free_clusters_count = clusters_freed +
ext4_free_group_clusters(sb, desc);
ext4_free_group_clusters_set(sb, desc, free_clusters_count);
ext4_block_bitmap_csum_set(sb, desc, bitmap_bh);
ext4_group_desc_csum_set(sb, block_group, desc);
ext4_unlock_group(sb, block_group);
percpu_counter_add(&sbi->s_freeclusters_counter,
clusters_freed);
if (sbi->s_log_groups_per_flex) {
ext4_group_t flex_group = ext4_flex_group(sbi, block_group);
atomic64_add(clusters_freed,
&sbi_array_rcu_deref(sbi, s_flex_groups,
flex_group)->free_clusters);
}
ext4_mb_unload_buddy(&e4b);
/* We dirtied the bitmap block */
BUFFER_TRACE(bitmap_bh, "dirtied bitmap block");
err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh);
/* And the group descriptor block */
BUFFER_TRACE(gd_bh, "dirtied group descriptor block");
ret = ext4_handle_dirty_metadata(handle, NULL, gd_bh);
if (!err)
err = ret;
error_return:
brelse(bitmap_bh);
ext4_std_error(sb, err);
return err;
}
/**
* ext4_trim_extent -- function to TRIM one single free extent in the group
* @sb: super block for the file system
* @start: starting block of the free extent in the alloc. group
* @count: number of blocks to TRIM
* @e4b: ext4 buddy for the group
*
* Trim "count" blocks starting at "start" in the "group". To assure that no
* one will allocate those blocks, mark it as used in buddy bitmap. This must
* be called with under the group lock.
*/
static int ext4_trim_extent(struct super_block *sb,
int start, int count, struct ext4_buddy *e4b)
__releases(bitlock)
__acquires(bitlock)
{
struct ext4_free_extent ex;
ext4_group_t group = e4b->bd_group;
int ret = 0;
trace_ext4_trim_extent(sb, group, start, count);
assert_spin_locked(ext4_group_lock_ptr(sb, group));
ex.fe_start = start;
ex.fe_group = group;
ex.fe_len = count;
/*
* Mark blocks used, so no one can reuse them while
* being trimmed.
*/
mb_mark_used(e4b, &ex);
ext4_unlock_group(sb, group);
ret = ext4_issue_discard(sb, group, start, count, NULL);
ext4_lock_group(sb, group);
mb_free_blocks(NULL, e4b, start, ex.fe_len);
return ret;
}
static int ext4_try_to_trim_range(struct super_block *sb,
struct ext4_buddy *e4b, ext4_grpblk_t start,
ext4_grpblk_t max, ext4_grpblk_t minblocks)
__acquires(ext4_group_lock_ptr(sb, e4b->bd_group))
__releases(ext4_group_lock_ptr(sb, e4b->bd_group))
{
ext4_grpblk_t next, count, free_count;
void *bitmap;
bitmap = e4b->bd_bitmap;
start = (e4b->bd_info->bb_first_free > start) ?
e4b->bd_info->bb_first_free : start;
count = 0;
free_count = 0;
while (start <= max) {
start = mb_find_next_zero_bit(bitmap, max + 1, start);
if (start > max)
break;
next = mb_find_next_bit(bitmap, max + 1, start);
if ((next - start) >= minblocks) {
int ret = ext4_trim_extent(sb, start, next - start, e4b);
if (ret && ret != -EOPNOTSUPP)
break;
count += next - start;
}
free_count += next - start;
start = next + 1;
if (fatal_signal_pending(current)) {
count = -ERESTARTSYS;
break;
}
if (need_resched()) {
ext4_unlock_group(sb, e4b->bd_group);
cond_resched();
ext4_lock_group(sb, e4b->bd_group);
}
if ((e4b->bd_info->bb_free - free_count) < minblocks)
break;
}
return count;
}
/**
* ext4_trim_all_free -- function to trim all free space in alloc. group
* @sb: super block for file system
* @group: group to be trimmed
* @start: first group block to examine
* @max: last group block to examine
* @minblocks: minimum extent block count
* @set_trimmed: set the trimmed flag if at least one block is trimmed
*
* ext4_trim_all_free walks through group's block bitmap searching for free
* extents. When the free extent is found, mark it as used in group buddy
* bitmap. Then issue a TRIM command on this extent and free the extent in
* the group buddy bitmap.
*/
static ext4_grpblk_t
ext4_trim_all_free(struct super_block *sb, ext4_group_t group,
ext4_grpblk_t start, ext4_grpblk_t max,
ext4_grpblk_t minblocks, bool set_trimmed)
{
struct ext4_buddy e4b;
int ret;
trace_ext4_trim_all_free(sb, group, start, max);
ret = ext4_mb_load_buddy(sb, group, &e4b);
if (ret) {
ext4_warning(sb, "Error %d loading buddy information for %u",
ret, group);
return ret;
}
ext4_lock_group(sb, group);
if (!EXT4_MB_GRP_WAS_TRIMMED(e4b.bd_info) ||
minblocks < EXT4_SB(sb)->s_last_trim_minblks) {
ret = ext4_try_to_trim_range(sb, &e4b, start, max, minblocks);
if (ret >= 0 && set_trimmed)
EXT4_MB_GRP_SET_TRIMMED(e4b.bd_info);
} else {
ret = 0;
}
ext4_unlock_group(sb, group);
ext4_mb_unload_buddy(&e4b);
ext4_debug("trimmed %d blocks in the group %d\n",
ret, group);
return ret;
}
/**
* ext4_trim_fs() -- trim ioctl handle function
* @sb: superblock for filesystem
* @range: fstrim_range structure
*
* start: First Byte to trim
* len: number of Bytes to trim from start
* minlen: minimum extent length in Bytes
* ext4_trim_fs goes through all allocation groups containing Bytes from
* start to start+len. For each such a group ext4_trim_all_free function
* is invoked to trim all free space.
*/
int ext4_trim_fs(struct super_block *sb, struct fstrim_range *range)
{
unsigned int discard_granularity = bdev_discard_granularity(sb->s_bdev);
struct ext4_group_info *grp;
ext4_group_t group, first_group, last_group;
ext4_grpblk_t cnt = 0, first_cluster, last_cluster;
uint64_t start, end, minlen, trimmed = 0;
ext4_fsblk_t first_data_blk =
le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block);
ext4_fsblk_t max_blks = ext4_blocks_count(EXT4_SB(sb)->s_es);
bool whole_group, eof = false;
int ret = 0;
start = range->start >> sb->s_blocksize_bits;
end = start + (range->len >> sb->s_blocksize_bits) - 1;
minlen = EXT4_NUM_B2C(EXT4_SB(sb),
range->minlen >> sb->s_blocksize_bits);
if (minlen > EXT4_CLUSTERS_PER_GROUP(sb) ||
start >= max_blks ||
range->len < sb->s_blocksize)
return -EINVAL;
/* No point to try to trim less than discard granularity */
if (range->minlen < discard_granularity) {
minlen = EXT4_NUM_B2C(EXT4_SB(sb),
discard_granularity >> sb->s_blocksize_bits);
if (minlen > EXT4_CLUSTERS_PER_GROUP(sb))
goto out;
}
if (end >= max_blks - 1) {
end = max_blks - 1;
eof = true;
}
if (end <= first_data_blk)
goto out;
if (start < first_data_blk)
start = first_data_blk;
/* Determine first and last group to examine based on start and end */
ext4_get_group_no_and_offset(sb, (ext4_fsblk_t) start,
&first_group, &first_cluster);
ext4_get_group_no_and_offset(sb, (ext4_fsblk_t) end,
&last_group, &last_cluster);
/* end now represents the last cluster to discard in this group */
end = EXT4_CLUSTERS_PER_GROUP(sb) - 1;
whole_group = true;
for (group = first_group; group <= last_group; group++) {
grp = ext4_get_group_info(sb, group);
if (!grp)
continue;
/* We only do this if the grp has never been initialized */
if (unlikely(EXT4_MB_GRP_NEED_INIT(grp))) {
ret = ext4_mb_init_group(sb, group, GFP_NOFS);
if (ret)
break;
}
/*
* For all the groups except the last one, last cluster will
* always be EXT4_CLUSTERS_PER_GROUP(sb)-1, so we only need to
* change it for the last group, note that last_cluster is
* already computed earlier by ext4_get_group_no_and_offset()
*/
if (group == last_group) {
end = last_cluster;
whole_group = eof ? true : end == EXT4_CLUSTERS_PER_GROUP(sb) - 1;
}
if (grp->bb_free >= minlen) {
cnt = ext4_trim_all_free(sb, group, first_cluster,
end, minlen, whole_group);
if (cnt < 0) {
ret = cnt;
break;
}
trimmed += cnt;
}
/*
* For every group except the first one, we are sure
* that the first cluster to discard will be cluster #0.
*/
first_cluster = 0;
}
if (!ret)
EXT4_SB(sb)->s_last_trim_minblks = minlen;
out:
range->len = EXT4_C2B(EXT4_SB(sb), trimmed) << sb->s_blocksize_bits;
return ret;
}
/* Iterate all the free extents in the group. */
int
ext4_mballoc_query_range(
struct super_block *sb,
ext4_group_t group,
ext4_grpblk_t start,
ext4_grpblk_t end,
ext4_mballoc_query_range_fn formatter,
void *priv)
{
void *bitmap;
ext4_grpblk_t next;
struct ext4_buddy e4b;
int error;
error = ext4_mb_load_buddy(sb, group, &e4b);
if (error)
return error;
bitmap = e4b.bd_bitmap;
ext4_lock_group(sb, group);
start = (e4b.bd_info->bb_first_free > start) ?
e4b.bd_info->bb_first_free : start;
if (end >= EXT4_CLUSTERS_PER_GROUP(sb))
end = EXT4_CLUSTERS_PER_GROUP(sb) - 1;
while (start <= end) {
start = mb_find_next_zero_bit(bitmap, end + 1, start);
if (start > end)
break;
next = mb_find_next_bit(bitmap, end + 1, start);
ext4_unlock_group(sb, group);
error = formatter(sb, group, start, next - start, priv);
if (error)
goto out_unload;
ext4_lock_group(sb, group);
start = next + 1;
}
ext4_unlock_group(sb, group);
out_unload:
ext4_mb_unload_buddy(&e4b);
return error;
}
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