linux/fs/btrfs/backref.c

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/*
* Copyright (C) 2011 STRATO. All rights reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public
* License v2 as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public
* License along with this program; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 021110-1307, USA.
*/
#include <linux/vmalloc.h>
#include "ctree.h"
#include "disk-io.h"
#include "backref.h"
#include "ulist.h"
#include "transaction.h"
#include "delayed-ref.h"
#include "locking.h"
struct extent_inode_elem {
u64 inum;
u64 offset;
struct extent_inode_elem *next;
};
static int check_extent_in_eb(struct btrfs_key *key, struct extent_buffer *eb,
struct btrfs_file_extent_item *fi,
u64 extent_item_pos,
struct extent_inode_elem **eie)
{
u64 offset = 0;
struct extent_inode_elem *e;
if (!btrfs_file_extent_compression(eb, fi) &&
!btrfs_file_extent_encryption(eb, fi) &&
!btrfs_file_extent_other_encoding(eb, fi)) {
u64 data_offset;
u64 data_len;
data_offset = btrfs_file_extent_offset(eb, fi);
data_len = btrfs_file_extent_num_bytes(eb, fi);
if (extent_item_pos < data_offset ||
extent_item_pos >= data_offset + data_len)
return 1;
offset = extent_item_pos - data_offset;
}
e = kmalloc(sizeof(*e), GFP_NOFS);
if (!e)
return -ENOMEM;
e->next = *eie;
e->inum = key->objectid;
e->offset = key->offset + offset;
*eie = e;
return 0;
}
static void free_inode_elem_list(struct extent_inode_elem *eie)
{
struct extent_inode_elem *eie_next;
for (; eie; eie = eie_next) {
eie_next = eie->next;
kfree(eie);
}
}
static int find_extent_in_eb(struct extent_buffer *eb, u64 wanted_disk_byte,
u64 extent_item_pos,
struct extent_inode_elem **eie)
{
u64 disk_byte;
struct btrfs_key key;
struct btrfs_file_extent_item *fi;
int slot;
int nritems;
int extent_type;
int ret;
/*
* from the shared data ref, we only have the leaf but we need
* the key. thus, we must look into all items and see that we
* find one (some) with a reference to our extent item.
*/
nritems = btrfs_header_nritems(eb);
for (slot = 0; slot < nritems; ++slot) {
btrfs_item_key_to_cpu(eb, &key, slot);
if (key.type != BTRFS_EXTENT_DATA_KEY)
continue;
fi = btrfs_item_ptr(eb, slot, struct btrfs_file_extent_item);
extent_type = btrfs_file_extent_type(eb, fi);
if (extent_type == BTRFS_FILE_EXTENT_INLINE)
continue;
/* don't skip BTRFS_FILE_EXTENT_PREALLOC, we can handle that */
disk_byte = btrfs_file_extent_disk_bytenr(eb, fi);
if (disk_byte != wanted_disk_byte)
continue;
ret = check_extent_in_eb(&key, eb, fi, extent_item_pos, eie);
if (ret < 0)
return ret;
}
return 0;
}
/*
* this structure records all encountered refs on the way up to the root
*/
struct __prelim_ref {
struct list_head list;
u64 root_id;
struct btrfs_key key_for_search;
int level;
int count;
struct extent_inode_elem *inode_list;
u64 parent;
u64 wanted_disk_byte;
};
static struct kmem_cache *btrfs_prelim_ref_cache;
int __init btrfs_prelim_ref_init(void)
{
btrfs_prelim_ref_cache = kmem_cache_create("btrfs_prelim_ref",
sizeof(struct __prelim_ref),
0,
SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD,
NULL);
if (!btrfs_prelim_ref_cache)
return -ENOMEM;
return 0;
}
void btrfs_prelim_ref_exit(void)
{
if (btrfs_prelim_ref_cache)
kmem_cache_destroy(btrfs_prelim_ref_cache);
}
/*
* the rules for all callers of this function are:
* - obtaining the parent is the goal
* - if you add a key, you must know that it is a correct key
* - if you cannot add the parent or a correct key, then we will look into the
* block later to set a correct key
*
* delayed refs
* ============
* backref type | shared | indirect | shared | indirect
* information | tree | tree | data | data
* --------------------+--------+----------+--------+----------
* parent logical | y | - | - | -
* key to resolve | - | y | y | y
* tree block logical | - | - | - | -
* root for resolving | y | y | y | y
*
* - column 1: we've the parent -> done
* - column 2, 3, 4: we use the key to find the parent
*
* on disk refs (inline or keyed)
* ==============================
* backref type | shared | indirect | shared | indirect
* information | tree | tree | data | data
* --------------------+--------+----------+--------+----------
* parent logical | y | - | y | -
* key to resolve | - | - | - | y
* tree block logical | y | y | y | y
* root for resolving | - | y | y | y
*
* - column 1, 3: we've the parent -> done
* - column 2: we take the first key from the block to find the parent
* (see __add_missing_keys)
* - column 4: we use the key to find the parent
*
* additional information that's available but not required to find the parent
* block might help in merging entries to gain some speed.
*/
static int __add_prelim_ref(struct list_head *head, u64 root_id,
struct btrfs_key *key, int level,
u64 parent, u64 wanted_disk_byte, int count,
gfp_t gfp_mask)
{
struct __prelim_ref *ref;
Btrfs: fix a crash when running balance and defrag concurrently Running balance and defrag concurrently can end up with a crash: kernel BUG at fs/btrfs/relocation.c:4528! RIP: 0010:[<ffffffffa01ac33b>] [<ffffffffa01ac33b>] btrfs_reloc_cow_block+ 0x1eb/0x230 [btrfs] Call Trace: [<ffffffffa01398c1>] ? update_ref_for_cow+0x241/0x380 [btrfs] [<ffffffffa0180bad>] ? copy_extent_buffer+0xad/0x110 [btrfs] [<ffffffffa0139da1>] __btrfs_cow_block+0x3a1/0x520 [btrfs] [<ffffffffa013a0b6>] btrfs_cow_block+0x116/0x1b0 [btrfs] [<ffffffffa013ddad>] btrfs_search_slot+0x43d/0x970 [btrfs] [<ffffffffa0153c57>] btrfs_lookup_file_extent+0x37/0x40 [btrfs] [<ffffffffa0172a5e>] __btrfs_drop_extents+0x11e/0xae0 [btrfs] [<ffffffffa013b3fd>] ? generic_bin_search.constprop.39+0x8d/0x1a0 [btrfs] [<ffffffff8117d14a>] ? kmem_cache_alloc+0x1da/0x200 [<ffffffffa0138e7a>] ? btrfs_alloc_path+0x1a/0x20 [btrfs] [<ffffffffa0173ef0>] btrfs_drop_extents+0x60/0x90 [btrfs] [<ffffffffa016b24d>] relink_extent_backref+0x2ed/0x780 [btrfs] [<ffffffffa0162fe0>] ? btrfs_submit_bio_hook+0x1e0/0x1e0 [btrfs] [<ffffffffa01b8ed7>] ? iterate_inodes_from_logical+0x87/0xa0 [btrfs] [<ffffffffa016b909>] btrfs_finish_ordered_io+0x229/0xac0 [btrfs] [<ffffffffa016c3b5>] finish_ordered_fn+0x15/0x20 [btrfs] [<ffffffffa018cbe5>] worker_loop+0x125/0x4e0 [btrfs] [<ffffffffa018cac0>] ? btrfs_queue_worker+0x300/0x300 [btrfs] [<ffffffff81075ea0>] kthread+0xc0/0xd0 [<ffffffff81075de0>] ? insert_kthread_work+0x40/0x40 [<ffffffff8164796c>] ret_from_fork+0x7c/0xb0 [<ffffffff81075de0>] ? insert_kthread_work+0x40/0x40 ---------------------------------------------------------------------- It turns out to be that balance operation will bump root's @last_snapshot, which enables snapshot-aware defrag path, and backref walking stuff will find data reloc tree as refs' parent, and hit the BUG_ON() during COW. As data reloc tree's data is just for relocation purpose, and will be deleted right after relocation is done, it's unnecessary to walk those refs belonged to data reloc tree, it'd be better to skip them. Signed-off-by: Liu Bo <bo.li.liu@oracle.com> Signed-off-by: Josef Bacik <jbacik@fusionio.com> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2013-10-30 05:25:24 +00:00
if (root_id == BTRFS_DATA_RELOC_TREE_OBJECTID)
return 0;
ref = kmem_cache_alloc(btrfs_prelim_ref_cache, gfp_mask);
if (!ref)
return -ENOMEM;
ref->root_id = root_id;
if (key)
ref->key_for_search = *key;
else
memset(&ref->key_for_search, 0, sizeof(ref->key_for_search));
ref->inode_list = NULL;
ref->level = level;
ref->count = count;
ref->parent = parent;
ref->wanted_disk_byte = wanted_disk_byte;
list_add_tail(&ref->list, head);
return 0;
}
static int add_all_parents(struct btrfs_root *root, struct btrfs_path *path,
struct ulist *parents, struct __prelim_ref *ref,
int level, u64 time_seq, const u64 *extent_item_pos)
{
int ret = 0;
int slot;
struct extent_buffer *eb;
struct btrfs_key key;
struct btrfs_key *key_for_search = &ref->key_for_search;
struct btrfs_file_extent_item *fi;
struct extent_inode_elem *eie = NULL, *old = NULL;
u64 disk_byte;
u64 wanted_disk_byte = ref->wanted_disk_byte;
u64 count = 0;
if (level != 0) {
eb = path->nodes[level];
ret = ulist_add(parents, eb->start, 0, GFP_NOFS);
if (ret < 0)
return ret;
return 0;
}
/*
* We normally enter this function with the path already pointing to
* the first item to check. But sometimes, we may enter it with
* slot==nritems. In that case, go to the next leaf before we continue.
*/
if (path->slots[0] >= btrfs_header_nritems(path->nodes[0]))
ret = btrfs_next_old_leaf(root, path, time_seq);
while (!ret && count < ref->count) {
eb = path->nodes[0];
slot = path->slots[0];
btrfs_item_key_to_cpu(eb, &key, slot);
if (key.objectid != key_for_search->objectid ||
key.type != BTRFS_EXTENT_DATA_KEY)
break;
fi = btrfs_item_ptr(eb, slot, struct btrfs_file_extent_item);
disk_byte = btrfs_file_extent_disk_bytenr(eb, fi);
if (disk_byte == wanted_disk_byte) {
eie = NULL;
old = NULL;
count++;
if (extent_item_pos) {
ret = check_extent_in_eb(&key, eb, fi,
*extent_item_pos,
&eie);
if (ret < 0)
break;
}
if (ret > 0)
goto next;
ret = ulist_add_merge(parents, eb->start,
(uintptr_t)eie,
(u64 *)&old, GFP_NOFS);
if (ret < 0)
break;
if (!ret && extent_item_pos) {
while (old->next)
old = old->next;
old->next = eie;
}
eie = NULL;
}
next:
ret = btrfs_next_old_item(root, path, time_seq);
}
if (ret > 0)
ret = 0;
else if (ret < 0)
free_inode_elem_list(eie);
return ret;
}
/*
* resolve an indirect backref in the form (root_id, key, level)
* to a logical address
*/
static int __resolve_indirect_ref(struct btrfs_fs_info *fs_info,
struct btrfs_path *path, u64 time_seq,
struct __prelim_ref *ref,
struct ulist *parents,
const u64 *extent_item_pos)
{
struct btrfs_root *root;
struct btrfs_key root_key;
struct extent_buffer *eb;
int ret = 0;
int root_level;
int level = ref->level;
int index;
root_key.objectid = ref->root_id;
root_key.type = BTRFS_ROOT_ITEM_KEY;
root_key.offset = (u64)-1;
index = srcu_read_lock(&fs_info->subvol_srcu);
root = btrfs_read_fs_root_no_name(fs_info, &root_key);
if (IS_ERR(root)) {
srcu_read_unlock(&fs_info->subvol_srcu, index);
ret = PTR_ERR(root);
goto out;
}
root_level = btrfs_old_root_level(root, time_seq);
if (root_level + 1 == level) {
srcu_read_unlock(&fs_info->subvol_srcu, index);
goto out;
}
path->lowest_level = level;
ret = btrfs_search_old_slot(root, &ref->key_for_search, path, time_seq);
/* root node has been locked, we can release @subvol_srcu safely here */
srcu_read_unlock(&fs_info->subvol_srcu, index);
pr_debug("search slot in root %llu (level %d, ref count %d) returned "
"%d for key (%llu %u %llu)\n",
ref->root_id, level, ref->count, ret,
ref->key_for_search.objectid, ref->key_for_search.type,
ref->key_for_search.offset);
if (ret < 0)
goto out;
eb = path->nodes[level];
while (!eb) {
if (WARN_ON(!level)) {
ret = 1;
goto out;
}
level--;
eb = path->nodes[level];
}
ret = add_all_parents(root, path, parents, ref, level, time_seq,
extent_item_pos);
out:
path->lowest_level = 0;
btrfs_release_path(path);
return ret;
}
/*
* resolve all indirect backrefs from the list
*/
static int __resolve_indirect_refs(struct btrfs_fs_info *fs_info,
struct btrfs_path *path, u64 time_seq,
struct list_head *head,
const u64 *extent_item_pos)
{
int err;
int ret = 0;
struct __prelim_ref *ref;
struct __prelim_ref *ref_safe;
struct __prelim_ref *new_ref;
struct ulist *parents;
struct ulist_node *node;
struct ulist_iterator uiter;
parents = ulist_alloc(GFP_NOFS);
if (!parents)
return -ENOMEM;
/*
* _safe allows us to insert directly after the current item without
* iterating over the newly inserted items.
* we're also allowed to re-assign ref during iteration.
*/
list_for_each_entry_safe(ref, ref_safe, head, list) {
if (ref->parent) /* already direct */
continue;
if (ref->count == 0)
continue;
err = __resolve_indirect_ref(fs_info, path, time_seq, ref,
parents, extent_item_pos);
/*
* we can only tolerate ENOENT,otherwise,we should catch error
* and return directly.
*/
if (err == -ENOENT) {
continue;
} else if (err) {
ret = err;
goto out;
}
/* we put the first parent into the ref at hand */
ULIST_ITER_INIT(&uiter);
node = ulist_next(parents, &uiter);
ref->parent = node ? node->val : 0;
ref->inode_list = node ?
(struct extent_inode_elem *)(uintptr_t)node->aux : NULL;
/* additional parents require new refs being added here */
while ((node = ulist_next(parents, &uiter))) {
new_ref = kmem_cache_alloc(btrfs_prelim_ref_cache,
GFP_NOFS);
if (!new_ref) {
ret = -ENOMEM;
goto out;
}
memcpy(new_ref, ref, sizeof(*ref));
new_ref->parent = node->val;
new_ref->inode_list = (struct extent_inode_elem *)
(uintptr_t)node->aux;
list_add(&new_ref->list, &ref->list);
}
ulist_reinit(parents);
}
out:
ulist_free(parents);
return ret;
}
static inline int ref_for_same_block(struct __prelim_ref *ref1,
struct __prelim_ref *ref2)
{
if (ref1->level != ref2->level)
return 0;
if (ref1->root_id != ref2->root_id)
return 0;
if (ref1->key_for_search.type != ref2->key_for_search.type)
return 0;
if (ref1->key_for_search.objectid != ref2->key_for_search.objectid)
return 0;
if (ref1->key_for_search.offset != ref2->key_for_search.offset)
return 0;
if (ref1->parent != ref2->parent)
return 0;
return 1;
}
/*
* read tree blocks and add keys where required.
*/
static int __add_missing_keys(struct btrfs_fs_info *fs_info,
struct list_head *head)
{
struct list_head *pos;
struct extent_buffer *eb;
list_for_each(pos, head) {
struct __prelim_ref *ref;
ref = list_entry(pos, struct __prelim_ref, list);
if (ref->parent)
continue;
if (ref->key_for_search.type)
continue;
BUG_ON(!ref->wanted_disk_byte);
eb = read_tree_block(fs_info->tree_root, ref->wanted_disk_byte,
fs_info->tree_root->leafsize, 0);
if (!eb || !extent_buffer_uptodate(eb)) {
free_extent_buffer(eb);
return -EIO;
}
btrfs_tree_read_lock(eb);
if (btrfs_header_level(eb) == 0)
btrfs_item_key_to_cpu(eb, &ref->key_for_search, 0);
else
btrfs_node_key_to_cpu(eb, &ref->key_for_search, 0);
btrfs_tree_read_unlock(eb);
free_extent_buffer(eb);
}
return 0;
}
/*
* merge two lists of backrefs and adjust counts accordingly
*
* mode = 1: merge identical keys, if key is set
* FIXME: if we add more keys in __add_prelim_ref, we can merge more here.
* additionally, we could even add a key range for the blocks we
* looked into to merge even more (-> replace unresolved refs by those
* having a parent).
* mode = 2: merge identical parents
*/
static void __merge_refs(struct list_head *head, int mode)
{
struct list_head *pos1;
list_for_each(pos1, head) {
struct list_head *n2;
struct list_head *pos2;
struct __prelim_ref *ref1;
ref1 = list_entry(pos1, struct __prelim_ref, list);
for (pos2 = pos1->next, n2 = pos2->next; pos2 != head;
pos2 = n2, n2 = pos2->next) {
struct __prelim_ref *ref2;
struct __prelim_ref *xchg;
struct extent_inode_elem *eie;
ref2 = list_entry(pos2, struct __prelim_ref, list);
if (mode == 1) {
if (!ref_for_same_block(ref1, ref2))
continue;
if (!ref1->parent && ref2->parent) {
xchg = ref1;
ref1 = ref2;
ref2 = xchg;
}
} else {
if (ref1->parent != ref2->parent)
continue;
}
eie = ref1->inode_list;
while (eie && eie->next)
eie = eie->next;
if (eie)
eie->next = ref2->inode_list;
else
ref1->inode_list = ref2->inode_list;
ref1->count += ref2->count;
list_del(&ref2->list);
kmem_cache_free(btrfs_prelim_ref_cache, ref2);
}
}
}
/*
* add all currently queued delayed refs from this head whose seq nr is
* smaller or equal that seq to the list
*/
static int __add_delayed_refs(struct btrfs_delayed_ref_head *head, u64 seq,
struct list_head *prefs)
{
struct btrfs_delayed_extent_op *extent_op = head->extent_op;
struct rb_node *n = &head->node.rb_node;
struct btrfs_key key;
struct btrfs_key op_key = {0};
int sgn;
int ret = 0;
if (extent_op && extent_op->update_key)
btrfs_disk_key_to_cpu(&op_key, &extent_op->key);
spin_lock(&head->lock);
n = rb_first(&head->ref_root);
while (n) {
struct btrfs_delayed_ref_node *node;
node = rb_entry(n, struct btrfs_delayed_ref_node,
rb_node);
n = rb_next(n);
if (node->seq > seq)
continue;
switch (node->action) {
case BTRFS_ADD_DELAYED_EXTENT:
case BTRFS_UPDATE_DELAYED_HEAD:
WARN_ON(1);
continue;
case BTRFS_ADD_DELAYED_REF:
sgn = 1;
break;
case BTRFS_DROP_DELAYED_REF:
sgn = -1;
break;
default:
BUG_ON(1);
}
switch (node->type) {
case BTRFS_TREE_BLOCK_REF_KEY: {
struct btrfs_delayed_tree_ref *ref;
ref = btrfs_delayed_node_to_tree_ref(node);
ret = __add_prelim_ref(prefs, ref->root, &op_key,
ref->level + 1, 0, node->bytenr,
node->ref_mod * sgn, GFP_ATOMIC);
break;
}
case BTRFS_SHARED_BLOCK_REF_KEY: {
struct btrfs_delayed_tree_ref *ref;
ref = btrfs_delayed_node_to_tree_ref(node);
ret = __add_prelim_ref(prefs, ref->root, NULL,
ref->level + 1, ref->parent,
node->bytenr,
node->ref_mod * sgn, GFP_ATOMIC);
break;
}
case BTRFS_EXTENT_DATA_REF_KEY: {
struct btrfs_delayed_data_ref *ref;
ref = btrfs_delayed_node_to_data_ref(node);
key.objectid = ref->objectid;
key.type = BTRFS_EXTENT_DATA_KEY;
key.offset = ref->offset;
ret = __add_prelim_ref(prefs, ref->root, &key, 0, 0,
node->bytenr,
node->ref_mod * sgn, GFP_ATOMIC);
break;
}
case BTRFS_SHARED_DATA_REF_KEY: {
struct btrfs_delayed_data_ref *ref;
ref = btrfs_delayed_node_to_data_ref(node);
key.objectid = ref->objectid;
key.type = BTRFS_EXTENT_DATA_KEY;
key.offset = ref->offset;
ret = __add_prelim_ref(prefs, ref->root, &key, 0,
ref->parent, node->bytenr,
node->ref_mod * sgn, GFP_ATOMIC);
break;
}
default:
WARN_ON(1);
}
if (ret)
break;
}
spin_unlock(&head->lock);
return ret;
}
/*
* add all inline backrefs for bytenr to the list
*/
static int __add_inline_refs(struct btrfs_fs_info *fs_info,
struct btrfs_path *path, u64 bytenr,
int *info_level, struct list_head *prefs)
{
int ret = 0;
int slot;
struct extent_buffer *leaf;
struct btrfs_key key;
struct btrfs_key found_key;
unsigned long ptr;
unsigned long end;
struct btrfs_extent_item *ei;
u64 flags;
u64 item_size;
/*
* enumerate all inline refs
*/
leaf = path->nodes[0];
slot = path->slots[0];
item_size = btrfs_item_size_nr(leaf, slot);
BUG_ON(item_size < sizeof(*ei));
ei = btrfs_item_ptr(leaf, slot, struct btrfs_extent_item);
flags = btrfs_extent_flags(leaf, ei);
btrfs_item_key_to_cpu(leaf, &found_key, slot);
ptr = (unsigned long)(ei + 1);
end = (unsigned long)ei + item_size;
if (found_key.type == BTRFS_EXTENT_ITEM_KEY &&
flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
struct btrfs_tree_block_info *info;
info = (struct btrfs_tree_block_info *)ptr;
*info_level = btrfs_tree_block_level(leaf, info);
ptr += sizeof(struct btrfs_tree_block_info);
BUG_ON(ptr > end);
} else if (found_key.type == BTRFS_METADATA_ITEM_KEY) {
*info_level = found_key.offset;
} else {
BUG_ON(!(flags & BTRFS_EXTENT_FLAG_DATA));
}
while (ptr < end) {
struct btrfs_extent_inline_ref *iref;
u64 offset;
int type;
iref = (struct btrfs_extent_inline_ref *)ptr;
type = btrfs_extent_inline_ref_type(leaf, iref);
offset = btrfs_extent_inline_ref_offset(leaf, iref);
switch (type) {
case BTRFS_SHARED_BLOCK_REF_KEY:
ret = __add_prelim_ref(prefs, 0, NULL,
*info_level + 1, offset,
bytenr, 1, GFP_NOFS);
break;
case BTRFS_SHARED_DATA_REF_KEY: {
struct btrfs_shared_data_ref *sdref;
int count;
sdref = (struct btrfs_shared_data_ref *)(iref + 1);
count = btrfs_shared_data_ref_count(leaf, sdref);
ret = __add_prelim_ref(prefs, 0, NULL, 0, offset,
bytenr, count, GFP_NOFS);
break;
}
case BTRFS_TREE_BLOCK_REF_KEY:
ret = __add_prelim_ref(prefs, offset, NULL,
*info_level + 1, 0,
bytenr, 1, GFP_NOFS);
break;
case BTRFS_EXTENT_DATA_REF_KEY: {
struct btrfs_extent_data_ref *dref;
int count;
u64 root;
dref = (struct btrfs_extent_data_ref *)(&iref->offset);
count = btrfs_extent_data_ref_count(leaf, dref);
key.objectid = btrfs_extent_data_ref_objectid(leaf,
dref);
key.type = BTRFS_EXTENT_DATA_KEY;
key.offset = btrfs_extent_data_ref_offset(leaf, dref);
root = btrfs_extent_data_ref_root(leaf, dref);
ret = __add_prelim_ref(prefs, root, &key, 0, 0,
bytenr, count, GFP_NOFS);
break;
}
default:
WARN_ON(1);
}
if (ret)
return ret;
ptr += btrfs_extent_inline_ref_size(type);
}
return 0;
}
/*
* add all non-inline backrefs for bytenr to the list
*/
static int __add_keyed_refs(struct btrfs_fs_info *fs_info,
struct btrfs_path *path, u64 bytenr,
int info_level, struct list_head *prefs)
{
struct btrfs_root *extent_root = fs_info->extent_root;
int ret;
int slot;
struct extent_buffer *leaf;
struct btrfs_key key;
while (1) {
ret = btrfs_next_item(extent_root, path);
if (ret < 0)
break;
if (ret) {
ret = 0;
break;
}
slot = path->slots[0];
leaf = path->nodes[0];
btrfs_item_key_to_cpu(leaf, &key, slot);
if (key.objectid != bytenr)
break;
if (key.type < BTRFS_TREE_BLOCK_REF_KEY)
continue;
if (key.type > BTRFS_SHARED_DATA_REF_KEY)
break;
switch (key.type) {
case BTRFS_SHARED_BLOCK_REF_KEY:
ret = __add_prelim_ref(prefs, 0, NULL,
info_level + 1, key.offset,
bytenr, 1, GFP_NOFS);
break;
case BTRFS_SHARED_DATA_REF_KEY: {
struct btrfs_shared_data_ref *sdref;
int count;
sdref = btrfs_item_ptr(leaf, slot,
struct btrfs_shared_data_ref);
count = btrfs_shared_data_ref_count(leaf, sdref);
ret = __add_prelim_ref(prefs, 0, NULL, 0, key.offset,
bytenr, count, GFP_NOFS);
break;
}
case BTRFS_TREE_BLOCK_REF_KEY:
ret = __add_prelim_ref(prefs, key.offset, NULL,
info_level + 1, 0,
bytenr, 1, GFP_NOFS);
break;
case BTRFS_EXTENT_DATA_REF_KEY: {
struct btrfs_extent_data_ref *dref;
int count;
u64 root;
dref = btrfs_item_ptr(leaf, slot,
struct btrfs_extent_data_ref);
count = btrfs_extent_data_ref_count(leaf, dref);
key.objectid = btrfs_extent_data_ref_objectid(leaf,
dref);
key.type = BTRFS_EXTENT_DATA_KEY;
key.offset = btrfs_extent_data_ref_offset(leaf, dref);
root = btrfs_extent_data_ref_root(leaf, dref);
ret = __add_prelim_ref(prefs, root, &key, 0, 0,
bytenr, count, GFP_NOFS);
break;
}
default:
WARN_ON(1);
}
if (ret)
return ret;
}
return ret;
}
/*
* this adds all existing backrefs (inline backrefs, backrefs and delayed
* refs) for the given bytenr to the refs list, merges duplicates and resolves
* indirect refs to their parent bytenr.
* When roots are found, they're added to the roots list
*
* FIXME some caching might speed things up
*/
static int find_parent_nodes(struct btrfs_trans_handle *trans,
struct btrfs_fs_info *fs_info, u64 bytenr,
u64 time_seq, struct ulist *refs,
struct ulist *roots, const u64 *extent_item_pos)
{
struct btrfs_key key;
struct btrfs_path *path;
struct btrfs_delayed_ref_root *delayed_refs = NULL;
struct btrfs_delayed_ref_head *head;
int info_level = 0;
int ret;
struct list_head prefs_delayed;
struct list_head prefs;
struct __prelim_ref *ref;
struct extent_inode_elem *eie = NULL;
INIT_LIST_HEAD(&prefs);
INIT_LIST_HEAD(&prefs_delayed);
key.objectid = bytenr;
key.offset = (u64)-1;
if (btrfs_fs_incompat(fs_info, SKINNY_METADATA))
key.type = BTRFS_METADATA_ITEM_KEY;
else
key.type = BTRFS_EXTENT_ITEM_KEY;
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
if (!trans)
path->search_commit_root = 1;
/*
* grab both a lock on the path and a lock on the delayed ref head.
* We need both to get a consistent picture of how the refs look
* at a specified point in time
*/
again:
head = NULL;
ret = btrfs_search_slot(trans, fs_info->extent_root, &key, path, 0, 0);
if (ret < 0)
goto out;
BUG_ON(ret == 0);
if (trans) {
/*
* look if there are updates for this ref queued and lock the
* head
*/
delayed_refs = &trans->transaction->delayed_refs;
spin_lock(&delayed_refs->lock);
head = btrfs_find_delayed_ref_head(trans, bytenr);
if (head) {
if (!mutex_trylock(&head->mutex)) {
atomic_inc(&head->node.refs);
spin_unlock(&delayed_refs->lock);
btrfs_release_path(path);
/*
* Mutex was contended, block until it's
* released and try again
*/
mutex_lock(&head->mutex);
mutex_unlock(&head->mutex);
btrfs_put_delayed_ref(&head->node);
goto again;
}
spin_unlock(&delayed_refs->lock);
ret = __add_delayed_refs(head, time_seq,
&prefs_delayed);
mutex_unlock(&head->mutex);
if (ret)
goto out;
} else {
spin_unlock(&delayed_refs->lock);
}
}
if (path->slots[0]) {
struct extent_buffer *leaf;
int slot;
path->slots[0]--;
leaf = path->nodes[0];
slot = path->slots[0];
btrfs_item_key_to_cpu(leaf, &key, slot);
if (key.objectid == bytenr &&
(key.type == BTRFS_EXTENT_ITEM_KEY ||
key.type == BTRFS_METADATA_ITEM_KEY)) {
ret = __add_inline_refs(fs_info, path, bytenr,
&info_level, &prefs);
if (ret)
goto out;
ret = __add_keyed_refs(fs_info, path, bytenr,
info_level, &prefs);
if (ret)
goto out;
}
}
btrfs_release_path(path);
list_splice_init(&prefs_delayed, &prefs);
ret = __add_missing_keys(fs_info, &prefs);
if (ret)
goto out;
__merge_refs(&prefs, 1);
ret = __resolve_indirect_refs(fs_info, path, time_seq, &prefs,
extent_item_pos);
if (ret)
goto out;
__merge_refs(&prefs, 2);
while (!list_empty(&prefs)) {
ref = list_first_entry(&prefs, struct __prelim_ref, list);
WARN_ON(ref->count < 0);
if (ref->count && ref->root_id && ref->parent == 0) {
/* no parent == root of tree */
ret = ulist_add(roots, ref->root_id, 0, GFP_NOFS);
if (ret < 0)
goto out;
}
if (ref->count && ref->parent) {
if (extent_item_pos && !ref->inode_list) {
u32 bsz;
struct extent_buffer *eb;
bsz = btrfs_level_size(fs_info->extent_root,
info_level);
eb = read_tree_block(fs_info->extent_root,
ref->parent, bsz, 0);
if (!eb || !extent_buffer_uptodate(eb)) {
free_extent_buffer(eb);
ret = -EIO;
goto out;
}
ret = find_extent_in_eb(eb, bytenr,
*extent_item_pos, &eie);
free_extent_buffer(eb);
if (ret < 0)
goto out;
ref->inode_list = eie;
}
ret = ulist_add_merge(refs, ref->parent,
(uintptr_t)ref->inode_list,
(u64 *)&eie, GFP_NOFS);
if (ret < 0)
goto out;
if (!ret && extent_item_pos) {
/*
* we've recorded that parent, so we must extend
* its inode list here
*/
BUG_ON(!eie);
while (eie->next)
eie = eie->next;
eie->next = ref->inode_list;
}
eie = NULL;
}
list_del(&ref->list);
kmem_cache_free(btrfs_prelim_ref_cache, ref);
}
out:
btrfs_free_path(path);
while (!list_empty(&prefs)) {
ref = list_first_entry(&prefs, struct __prelim_ref, list);
list_del(&ref->list);
kmem_cache_free(btrfs_prelim_ref_cache, ref);
}
while (!list_empty(&prefs_delayed)) {
ref = list_first_entry(&prefs_delayed, struct __prelim_ref,
list);
list_del(&ref->list);
kmem_cache_free(btrfs_prelim_ref_cache, ref);
}
if (ret < 0)
free_inode_elem_list(eie);
return ret;
}
static void free_leaf_list(struct ulist *blocks)
{
struct ulist_node *node = NULL;
struct extent_inode_elem *eie;
struct ulist_iterator uiter;
ULIST_ITER_INIT(&uiter);
while ((node = ulist_next(blocks, &uiter))) {
if (!node->aux)
continue;
eie = (struct extent_inode_elem *)(uintptr_t)node->aux;
free_inode_elem_list(eie);
node->aux = 0;
}
ulist_free(blocks);
}
/*
* Finds all leafs with a reference to the specified combination of bytenr and
* offset. key_list_head will point to a list of corresponding keys (caller must
* free each list element). The leafs will be stored in the leafs ulist, which
* must be freed with ulist_free.
*
* returns 0 on success, <0 on error
*/
static int btrfs_find_all_leafs(struct btrfs_trans_handle *trans,
struct btrfs_fs_info *fs_info, u64 bytenr,
u64 time_seq, struct ulist **leafs,
const u64 *extent_item_pos)
{
struct ulist *tmp;
int ret;
tmp = ulist_alloc(GFP_NOFS);
if (!tmp)
return -ENOMEM;
*leafs = ulist_alloc(GFP_NOFS);
if (!*leafs) {
ulist_free(tmp);
return -ENOMEM;
}
ret = find_parent_nodes(trans, fs_info, bytenr,
time_seq, *leafs, tmp, extent_item_pos);
ulist_free(tmp);
if (ret < 0 && ret != -ENOENT) {
free_leaf_list(*leafs);
return ret;
}
return 0;
}
/*
* walk all backrefs for a given extent to find all roots that reference this
* extent. Walking a backref means finding all extents that reference this
* extent and in turn walk the backrefs of those, too. Naturally this is a
* recursive process, but here it is implemented in an iterative fashion: We
* find all referencing extents for the extent in question and put them on a
* list. In turn, we find all referencing extents for those, further appending
* to the list. The way we iterate the list allows adding more elements after
* the current while iterating. The process stops when we reach the end of the
* list. Found roots are added to the roots list.
*
* returns 0 on success, < 0 on error.
*/
int btrfs_find_all_roots(struct btrfs_trans_handle *trans,
struct btrfs_fs_info *fs_info, u64 bytenr,
u64 time_seq, struct ulist **roots)
{
struct ulist *tmp;
struct ulist_node *node = NULL;
struct ulist_iterator uiter;
int ret;
tmp = ulist_alloc(GFP_NOFS);
if (!tmp)
return -ENOMEM;
*roots = ulist_alloc(GFP_NOFS);
if (!*roots) {
ulist_free(tmp);
return -ENOMEM;
}
ULIST_ITER_INIT(&uiter);
while (1) {
ret = find_parent_nodes(trans, fs_info, bytenr,
time_seq, tmp, *roots, NULL);
if (ret < 0 && ret != -ENOENT) {
ulist_free(tmp);
ulist_free(*roots);
return ret;
}
node = ulist_next(tmp, &uiter);
if (!node)
break;
bytenr = node->val;
Btrfs: add a reschedule point in btrfs_find_all_roots() I can easily trigger the following warnings when enabling quota in my virtual machine(running Opensuse), Steps are firstly creating a subvolume full of fragment extents, and then create many snapshots (500 in my test case). [ 2362.808459] BUG: soft lockup - CPU#0 stuck for 22s! [btrfs-qgroup-re:1970] [ 2362.809023] task: e4af8450 ti: e371c000 task.ti: e371c000 [ 2362.809026] EIP: 0060:[<fa38f4ae>] EFLAGS: 00000246 CPU: 0 [ 2362.809049] EIP is at __merge_refs+0x5e/0x100 [btrfs] [ 2362.809051] EAX: 00000000 EBX: cfadbcf0 ECX: 00000000 EDX: cfadbcb0 [ 2362.809052] ESI: dd8d3370 EDI: e371dde0 EBP: e371dd6c ESP: e371dd5c [ 2362.809054] DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068 [ 2362.809055] CR0: 80050033 CR2: ac454d50 CR3: 009a9000 CR4: 001407d0 [ 2362.809099] Stack: [ 2362.809100] 00000001 e371dde0 dfcc6890 f29f8000 e371de28 fa39016d 00000011 00000001 [ 2362.809105] 99bfc000 00000000 93928000 00000000 00000001 00000050 e371dda8 00000001 [ 2362.809109] f3a31000 f3413000 00000001 e371ddb8 000040a8 00000202 00000000 00000023 [ 2362.809113] Call Trace: [ 2362.809136] [<fa39016d>] find_parent_nodes+0x34d/0x1280 [btrfs] [ 2362.809156] [<fa391172>] btrfs_find_all_roots+0xb2/0x110 [btrfs] [ 2362.809174] [<fa3934a8>] btrfs_qgroup_rescan_worker+0x358/0x7a0 [btrfs] [ 2362.809180] [<c024d0ce>] ? lock_timer_base.isra.39+0x1e/0x40 [ 2362.809199] [<fa3648df>] worker_loop+0xff/0x470 [btrfs] [ 2362.809204] [<c027a88a>] ? __wake_up_locked+0x1a/0x20 [ 2362.809221] [<fa3647e0>] ? btrfs_queue_worker+0x2b0/0x2b0 [btrfs] [ 2362.809225] [<c025ebbc>] kthread+0x9c/0xb0 [ 2362.809229] [<c06b487b>] ret_from_kernel_thread+0x1b/0x30 [ 2362.809233] [<c025eb20>] ? kthread_create_on_node+0x110/0x110 By adding a reschedule point at the end of btrfs_find_all_roots(), i no longer hit these warnings. Cc: Josef Bacik <jbacik@fb.com> Signed-off-by: Wang Shilong <wangsl.fnst@cn.fujitsu.com> Reviewed-by: David Sterba <dsterba@suse.cz> Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Chris Mason <clm@fb.com>
2014-01-26 14:32:18 +00:00
cond_resched();
}
ulist_free(tmp);
return 0;
}
/*
* this makes the path point to (inum INODE_ITEM ioff)
*/
int inode_item_info(u64 inum, u64 ioff, struct btrfs_root *fs_root,
struct btrfs_path *path)
{
struct btrfs_key key;
return btrfs_find_item(fs_root, path, inum, ioff,
BTRFS_INODE_ITEM_KEY, &key);
}
static int inode_ref_info(u64 inum, u64 ioff, struct btrfs_root *fs_root,
struct btrfs_path *path,
struct btrfs_key *found_key)
{
return btrfs_find_item(fs_root, path, inum, ioff,
BTRFS_INODE_REF_KEY, found_key);
}
int btrfs_find_one_extref(struct btrfs_root *root, u64 inode_objectid,
u64 start_off, struct btrfs_path *path,
struct btrfs_inode_extref **ret_extref,
u64 *found_off)
{
int ret, slot;
struct btrfs_key key;
struct btrfs_key found_key;
struct btrfs_inode_extref *extref;
struct extent_buffer *leaf;
unsigned long ptr;
key.objectid = inode_objectid;
btrfs_set_key_type(&key, BTRFS_INODE_EXTREF_KEY);
key.offset = start_off;
ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
if (ret < 0)
return ret;
while (1) {
leaf = path->nodes[0];
slot = path->slots[0];
if (slot >= btrfs_header_nritems(leaf)) {
/*
* If the item at offset is not found,
* btrfs_search_slot will point us to the slot
* where it should be inserted. In our case
* that will be the slot directly before the
* next INODE_REF_KEY_V2 item. In the case
* that we're pointing to the last slot in a
* leaf, we must move one leaf over.
*/
ret = btrfs_next_leaf(root, path);
if (ret) {
if (ret >= 1)
ret = -ENOENT;
break;
}
continue;
}
btrfs_item_key_to_cpu(leaf, &found_key, slot);
/*
* Check that we're still looking at an extended ref key for
* this particular objectid. If we have different
* objectid or type then there are no more to be found
* in the tree and we can exit.
*/
ret = -ENOENT;
if (found_key.objectid != inode_objectid)
break;
if (btrfs_key_type(&found_key) != BTRFS_INODE_EXTREF_KEY)
break;
ret = 0;
ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
extref = (struct btrfs_inode_extref *)ptr;
*ret_extref = extref;
if (found_off)
*found_off = found_key.offset;
break;
}
return ret;
}
/*
* this iterates to turn a name (from iref/extref) into a full filesystem path.
* Elements of the path are separated by '/' and the path is guaranteed to be
* 0-terminated. the path is only given within the current file system.
* Therefore, it never starts with a '/'. the caller is responsible to provide
* "size" bytes in "dest". the dest buffer will be filled backwards. finally,
* the start point of the resulting string is returned. this pointer is within
* dest, normally.
* in case the path buffer would overflow, the pointer is decremented further
* as if output was written to the buffer, though no more output is actually
* generated. that way, the caller can determine how much space would be
* required for the path to fit into the buffer. in that case, the returned
* value will be smaller than dest. callers must check this!
*/
char *btrfs_ref_to_path(struct btrfs_root *fs_root, struct btrfs_path *path,
u32 name_len, unsigned long name_off,
struct extent_buffer *eb_in, u64 parent,
char *dest, u32 size)
{
int slot;
u64 next_inum;
int ret;
s64 bytes_left = ((s64)size) - 1;
struct extent_buffer *eb = eb_in;
struct btrfs_key found_key;
int leave_spinning = path->leave_spinning;
struct btrfs_inode_ref *iref;
if (bytes_left >= 0)
dest[bytes_left] = '\0';
path->leave_spinning = 1;
while (1) {
bytes_left -= name_len;
if (bytes_left >= 0)
read_extent_buffer(eb, dest + bytes_left,
name_off, name_len);
if (eb != eb_in) {
btrfs_tree_read_unlock_blocking(eb);
free_extent_buffer(eb);
}
ret = inode_ref_info(parent, 0, fs_root, path, &found_key);
if (ret > 0)
ret = -ENOENT;
if (ret)
break;
next_inum = found_key.offset;
/* regular exit ahead */
if (parent == next_inum)
break;
slot = path->slots[0];
eb = path->nodes[0];
/* make sure we can use eb after releasing the path */
if (eb != eb_in) {
atomic_inc(&eb->refs);
btrfs_tree_read_lock(eb);
btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK);
}
btrfs_release_path(path);
iref = btrfs_item_ptr(eb, slot, struct btrfs_inode_ref);
name_len = btrfs_inode_ref_name_len(eb, iref);
name_off = (unsigned long)(iref + 1);
parent = next_inum;
--bytes_left;
if (bytes_left >= 0)
dest[bytes_left] = '/';
}
btrfs_release_path(path);
path->leave_spinning = leave_spinning;
if (ret)
return ERR_PTR(ret);
return dest + bytes_left;
}
/*
* this makes the path point to (logical EXTENT_ITEM *)
* returns BTRFS_EXTENT_FLAG_DATA for data, BTRFS_EXTENT_FLAG_TREE_BLOCK for
* tree blocks and <0 on error.
*/
int extent_from_logical(struct btrfs_fs_info *fs_info, u64 logical,
struct btrfs_path *path, struct btrfs_key *found_key,
u64 *flags_ret)
{
int ret;
u64 flags;
u64 size = 0;
u32 item_size;
struct extent_buffer *eb;
struct btrfs_extent_item *ei;
struct btrfs_key key;
if (btrfs_fs_incompat(fs_info, SKINNY_METADATA))
key.type = BTRFS_METADATA_ITEM_KEY;
else
key.type = BTRFS_EXTENT_ITEM_KEY;
key.objectid = logical;
key.offset = (u64)-1;
ret = btrfs_search_slot(NULL, fs_info->extent_root, &key, path, 0, 0);
if (ret < 0)
return ret;
while (1) {
u32 nritems;
if (path->slots[0] == 0) {
btrfs_set_path_blocking(path);
ret = btrfs_prev_leaf(fs_info->extent_root, path);
if (ret != 0) {
if (ret > 0) {
pr_debug("logical %llu is not within "
"any extent\n", logical);
ret = -ENOENT;
}
return ret;
}
} else {
path->slots[0]--;
}
nritems = btrfs_header_nritems(path->nodes[0]);
if (nritems == 0) {
pr_debug("logical %llu is not within any extent\n",
logical);
return -ENOENT;
}
if (path->slots[0] == nritems)
path->slots[0]--;
btrfs_item_key_to_cpu(path->nodes[0], found_key,
path->slots[0]);
if (found_key->type == BTRFS_EXTENT_ITEM_KEY ||
found_key->type == BTRFS_METADATA_ITEM_KEY)
break;
}
if (found_key->type == BTRFS_METADATA_ITEM_KEY)
size = fs_info->extent_root->leafsize;
else if (found_key->type == BTRFS_EXTENT_ITEM_KEY)
size = found_key->offset;
if (found_key->objectid > logical ||
found_key->objectid + size <= logical) {
pr_debug("logical %llu is not within any extent\n", logical);
return -ENOENT;
}
eb = path->nodes[0];
item_size = btrfs_item_size_nr(eb, path->slots[0]);
BUG_ON(item_size < sizeof(*ei));
ei = btrfs_item_ptr(eb, path->slots[0], struct btrfs_extent_item);
flags = btrfs_extent_flags(eb, ei);
pr_debug("logical %llu is at position %llu within the extent (%llu "
"EXTENT_ITEM %llu) flags %#llx size %u\n",
logical, logical - found_key->objectid, found_key->objectid,
found_key->offset, flags, item_size);
WARN_ON(!flags_ret);
if (flags_ret) {
if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK)
*flags_ret = BTRFS_EXTENT_FLAG_TREE_BLOCK;
else if (flags & BTRFS_EXTENT_FLAG_DATA)
*flags_ret = BTRFS_EXTENT_FLAG_DATA;
else
BUG_ON(1);
return 0;
}
return -EIO;
}
/*
* helper function to iterate extent inline refs. ptr must point to a 0 value
* for the first call and may be modified. it is used to track state.
* if more refs exist, 0 is returned and the next call to
* __get_extent_inline_ref must pass the modified ptr parameter to get the
* next ref. after the last ref was processed, 1 is returned.
* returns <0 on error
*/
static int __get_extent_inline_ref(unsigned long *ptr, struct extent_buffer *eb,
struct btrfs_extent_item *ei, u32 item_size,
struct btrfs_extent_inline_ref **out_eiref,
int *out_type)
{
unsigned long end;
u64 flags;
struct btrfs_tree_block_info *info;
if (!*ptr) {
/* first call */
flags = btrfs_extent_flags(eb, ei);
if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
info = (struct btrfs_tree_block_info *)(ei + 1);
*out_eiref =
(struct btrfs_extent_inline_ref *)(info + 1);
} else {
*out_eiref = (struct btrfs_extent_inline_ref *)(ei + 1);
}
*ptr = (unsigned long)*out_eiref;
if ((void *)*ptr >= (void *)ei + item_size)
return -ENOENT;
}
end = (unsigned long)ei + item_size;
*out_eiref = (struct btrfs_extent_inline_ref *)*ptr;
*out_type = btrfs_extent_inline_ref_type(eb, *out_eiref);
*ptr += btrfs_extent_inline_ref_size(*out_type);
WARN_ON(*ptr > end);
if (*ptr == end)
return 1; /* last */
return 0;
}
/*
* reads the tree block backref for an extent. tree level and root are returned
* through out_level and out_root. ptr must point to a 0 value for the first
* call and may be modified (see __get_extent_inline_ref comment).
* returns 0 if data was provided, 1 if there was no more data to provide or
* <0 on error.
*/
int tree_backref_for_extent(unsigned long *ptr, struct extent_buffer *eb,
struct btrfs_extent_item *ei, u32 item_size,
u64 *out_root, u8 *out_level)
{
int ret;
int type;
struct btrfs_tree_block_info *info;
struct btrfs_extent_inline_ref *eiref;
if (*ptr == (unsigned long)-1)
return 1;
while (1) {
ret = __get_extent_inline_ref(ptr, eb, ei, item_size,
&eiref, &type);
if (ret < 0)
return ret;
if (type == BTRFS_TREE_BLOCK_REF_KEY ||
type == BTRFS_SHARED_BLOCK_REF_KEY)
break;
if (ret == 1)
return 1;
}
/* we can treat both ref types equally here */
info = (struct btrfs_tree_block_info *)(ei + 1);
*out_root = btrfs_extent_inline_ref_offset(eb, eiref);
*out_level = btrfs_tree_block_level(eb, info);
if (ret == 1)
*ptr = (unsigned long)-1;
return 0;
}
static int iterate_leaf_refs(struct extent_inode_elem *inode_list,
u64 root, u64 extent_item_objectid,
iterate_extent_inodes_t *iterate, void *ctx)
{
struct extent_inode_elem *eie;
int ret = 0;
for (eie = inode_list; eie; eie = eie->next) {
pr_debug("ref for %llu resolved, key (%llu EXTEND_DATA %llu), "
"root %llu\n", extent_item_objectid,
eie->inum, eie->offset, root);
ret = iterate(eie->inum, eie->offset, root, ctx);
if (ret) {
pr_debug("stopping iteration for %llu due to ret=%d\n",
extent_item_objectid, ret);
break;
}
}
return ret;
}
/*
* calls iterate() for every inode that references the extent identified by
* the given parameters.
* when the iterator function returns a non-zero value, iteration stops.
*/
int iterate_extent_inodes(struct btrfs_fs_info *fs_info,
u64 extent_item_objectid, u64 extent_item_pos,
int search_commit_root,
iterate_extent_inodes_t *iterate, void *ctx)
{
int ret;
struct btrfs_trans_handle *trans = NULL;
struct ulist *refs = NULL;
struct ulist *roots = NULL;
struct ulist_node *ref_node = NULL;
struct ulist_node *root_node = NULL;
struct seq_list tree_mod_seq_elem = {};
struct ulist_iterator ref_uiter;
struct ulist_iterator root_uiter;
pr_debug("resolving all inodes for extent %llu\n",
extent_item_objectid);
if (!search_commit_root) {
trans = btrfs_join_transaction(fs_info->extent_root);
if (IS_ERR(trans))
return PTR_ERR(trans);
btrfs_get_tree_mod_seq(fs_info, &tree_mod_seq_elem);
}
ret = btrfs_find_all_leafs(trans, fs_info, extent_item_objectid,
tree_mod_seq_elem.seq, &refs,
&extent_item_pos);
if (ret)
goto out;
ULIST_ITER_INIT(&ref_uiter);
while (!ret && (ref_node = ulist_next(refs, &ref_uiter))) {
ret = btrfs_find_all_roots(trans, fs_info, ref_node->val,
tree_mod_seq_elem.seq, &roots);
if (ret)
break;
ULIST_ITER_INIT(&root_uiter);
while (!ret && (root_node = ulist_next(roots, &root_uiter))) {
pr_debug("root %llu references leaf %llu, data list "
"%#llx\n", root_node->val, ref_node->val,
ref_node->aux);
ret = iterate_leaf_refs((struct extent_inode_elem *)
(uintptr_t)ref_node->aux,
root_node->val,
extent_item_objectid,
iterate, ctx);
}
ulist_free(roots);
}
free_leaf_list(refs);
out:
if (!search_commit_root) {
btrfs_put_tree_mod_seq(fs_info, &tree_mod_seq_elem);
btrfs_end_transaction(trans, fs_info->extent_root);
}
return ret;
}
int iterate_inodes_from_logical(u64 logical, struct btrfs_fs_info *fs_info,
struct btrfs_path *path,
iterate_extent_inodes_t *iterate, void *ctx)
{
int ret;
u64 extent_item_pos;
u64 flags = 0;
struct btrfs_key found_key;
int search_commit_root = path->search_commit_root;
ret = extent_from_logical(fs_info, logical, path, &found_key, &flags);
btrfs_release_path(path);
if (ret < 0)
return ret;
if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK)
return -EINVAL;
extent_item_pos = logical - found_key.objectid;
ret = iterate_extent_inodes(fs_info, found_key.objectid,
extent_item_pos, search_commit_root,
iterate, ctx);
return ret;
}
typedef int (iterate_irefs_t)(u64 parent, u32 name_len, unsigned long name_off,
struct extent_buffer *eb, void *ctx);
static int iterate_inode_refs(u64 inum, struct btrfs_root *fs_root,
struct btrfs_path *path,
iterate_irefs_t *iterate, void *ctx)
{
int ret = 0;
int slot;
u32 cur;
u32 len;
u32 name_len;
u64 parent = 0;
int found = 0;
struct extent_buffer *eb;
struct btrfs_item *item;
struct btrfs_inode_ref *iref;
struct btrfs_key found_key;
while (!ret) {
ret = inode_ref_info(inum, parent ? parent+1 : 0, fs_root, path,
&found_key);
if (ret < 0)
break;
if (ret) {
ret = found ? 0 : -ENOENT;
break;
}
++found;
parent = found_key.offset;
slot = path->slots[0];
Btrfs: fix deadlock when iterating inode refs and running delayed inodes While running btrfs/004 from xfstests, after 503 iterations, dmesg reported a deadlock between tasks iterating inode refs and tasks running delayed inodes (during a transaction commit). It turns out that iterating inode refs implies doing one tree search and release all nodes in the path except the leaf node, and then passing that leaf node to btrfs_ref_to_path(), which in turn does another tree search without releasing the lock on the leaf node it received as parameter. This is a problem when other task wants to write to the btree as well and ends up updating the leaf that is read locked - the writer task locks the parent of the leaf and then blocks waiting for the leaf's lock to be released - at the same time, the task executing btrfs_ref_to_path() does a second tree search, without releasing the lock on the first leaf, and wants to access a leaf (the same or another one) that is a child of the same parent, resulting in a deadlock. The trace reported by lockdep follows. [84314.936373] INFO: task fsstress:11930 blocked for more than 120 seconds. [84314.936381] Tainted: G W O 3.12.0-fdm-btrfs-next-16+ #70 [84314.936383] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [84314.936386] fsstress D ffff8806e1bf8000 0 11930 11926 0x00000000 [84314.936393] ffff8804d6d89b78 0000000000000046 ffff8804d6d89b18 ffffffff810bd8bd [84314.936399] ffff8806e1bf8000 ffff8804d6d89fd8 ffff8804d6d89fd8 ffff8804d6d89fd8 [84314.936405] ffff880806308000 ffff8806e1bf8000 ffff8804d6d89c08 ffff8804deb8f190 [84314.936410] Call Trace: [84314.936421] [<ffffffff810bd8bd>] ? trace_hardirqs_on+0xd/0x10 [84314.936428] [<ffffffff81774269>] schedule+0x29/0x70 [84314.936451] [<ffffffffa0715bf5>] btrfs_tree_lock+0x75/0x270 [btrfs] [84314.936457] [<ffffffff810715c0>] ? __init_waitqueue_head+0x60/0x60 [84314.936470] [<ffffffffa06ba231>] btrfs_search_slot+0x7f1/0x930 [btrfs] [84314.936489] [<ffffffffa0731c2a>] ? __btrfs_run_delayed_items+0x13a/0x1e0 [btrfs] [84314.936504] [<ffffffffa06d2e1f>] btrfs_lookup_inode+0x2f/0xa0 [btrfs] [84314.936510] [<ffffffff810bd6ef>] ? trace_hardirqs_on_caller+0x1f/0x1e0 [84314.936528] [<ffffffffa073173c>] __btrfs_update_delayed_inode+0x4c/0x1d0 [btrfs] [84314.936543] [<ffffffffa0731c2a>] ? __btrfs_run_delayed_items+0x13a/0x1e0 [btrfs] [84314.936558] [<ffffffffa0731c2a>] ? __btrfs_run_delayed_items+0x13a/0x1e0 [btrfs] [84314.936573] [<ffffffffa0731c82>] __btrfs_run_delayed_items+0x192/0x1e0 [btrfs] [84314.936589] [<ffffffffa0731d03>] btrfs_run_delayed_items+0x13/0x20 [btrfs] [84314.936604] [<ffffffffa06dbcd4>] btrfs_flush_all_pending_stuffs+0x24/0x80 [btrfs] [84314.936620] [<ffffffffa06ddc13>] btrfs_commit_transaction+0x223/0xa20 [btrfs] [84314.936630] [<ffffffffa06ae5ae>] btrfs_sync_fs+0x6e/0x110 [btrfs] [84314.936635] [<ffffffff811d0b50>] ? __sync_filesystem+0x60/0x60 [84314.936639] [<ffffffff811d0b50>] ? __sync_filesystem+0x60/0x60 [84314.936643] [<ffffffff811d0b70>] sync_fs_one_sb+0x20/0x30 [84314.936648] [<ffffffff811a3541>] iterate_supers+0xf1/0x100 [84314.936652] [<ffffffff811d0c45>] sys_sync+0x55/0x90 [84314.936658] [<ffffffff8177ef12>] system_call_fastpath+0x16/0x1b [84314.936660] INFO: lockdep is turned off. [84314.936663] INFO: task btrfs:11955 blocked for more than 120 seconds. [84314.936666] Tainted: G W O 3.12.0-fdm-btrfs-next-16+ #70 [84314.936668] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [84314.936670] btrfs D ffff880541729a88 0 11955 11608 0x00000000 [84314.936674] ffff880541729a38 0000000000000046 ffff8805417299d8 ffffffff810bd8bd [84314.936680] ffff88075430c8a0 ffff880541729fd8 ffff880541729fd8 ffff880541729fd8 [84314.936685] ffffffff81c104e0 ffff88075430c8a0 ffff8804de8b00b8 ffff8804de8b0000 [84314.936690] Call Trace: [84314.936695] [<ffffffff810bd8bd>] ? trace_hardirqs_on+0xd/0x10 [84314.936700] [<ffffffff81774269>] schedule+0x29/0x70 [84314.936717] [<ffffffffa0715815>] btrfs_tree_read_lock+0xd5/0x140 [btrfs] [84314.936721] [<ffffffff810715c0>] ? __init_waitqueue_head+0x60/0x60 [84314.936733] [<ffffffffa06ba201>] btrfs_search_slot+0x7c1/0x930 [btrfs] [84314.936746] [<ffffffffa06bd505>] btrfs_find_item+0x55/0x160 [btrfs] [84314.936763] [<ffffffffa06ff689>] ? free_extent_buffer+0x49/0xc0 [btrfs] [84314.936780] [<ffffffffa073c9ca>] btrfs_ref_to_path+0xba/0x1e0 [btrfs] [84314.936797] [<ffffffffa06f9719>] ? release_extent_buffer+0xb9/0xe0 [btrfs] [84314.936813] [<ffffffffa06ff689>] ? free_extent_buffer+0x49/0xc0 [btrfs] [84314.936830] [<ffffffffa073cb50>] inode_to_path+0x60/0xd0 [btrfs] [84314.936846] [<ffffffffa073d365>] paths_from_inode+0x115/0x3c0 [btrfs] [84314.936851] [<ffffffff8118dd44>] ? kmem_cache_alloc_trace+0x114/0x200 [84314.936868] [<ffffffffa0714494>] btrfs_ioctl+0xf14/0x2030 [btrfs] [84314.936873] [<ffffffff817762db>] ? _raw_spin_unlock+0x2b/0x50 [84314.936877] [<ffffffff8116598f>] ? handle_mm_fault+0x34f/0xb00 [84314.936882] [<ffffffff81075563>] ? up_read+0x23/0x40 [84314.936886] [<ffffffff8177a41c>] ? __do_page_fault+0x20c/0x5a0 [84314.936892] [<ffffffff811b2946>] do_vfs_ioctl+0x96/0x570 [84314.936896] [<ffffffff81776e23>] ? error_sti+0x5/0x6 [84314.936901] [<ffffffff810b71e8>] ? trace_hardirqs_off_caller+0x28/0xd0 [84314.936906] [<ffffffff81776a09>] ? retint_swapgs+0xe/0x13 [84314.936910] [<ffffffff811b2eb1>] SyS_ioctl+0x91/0xb0 [84314.936915] [<ffffffff813eecde>] ? trace_hardirqs_on_thunk+0x3a/0x3f [84314.936920] [<ffffffff8177ef12>] system_call_fastpath+0x16/0x1b [84314.936922] INFO: lockdep is turned off. [84434.866873] INFO: task btrfs-transacti:11921 blocked for more than 120 seconds. [84434.866881] Tainted: G W O 3.12.0-fdm-btrfs-next-16+ #70 [84434.866883] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [84434.866886] btrfs-transacti D ffff880755b6a478 0 11921 2 0x00000000 [84434.866893] ffff8800735b9ce8 0000000000000046 ffff8800735b9c88 ffffffff810bd8bd [84434.866899] ffff8805a1b848a0 ffff8800735b9fd8 ffff8800735b9fd8 ffff8800735b9fd8 [84434.866904] ffffffff81c104e0 ffff8805a1b848a0 ffff880755b6a478 ffff8804cece78f0 [84434.866910] Call Trace: [84434.866920] [<ffffffff810bd8bd>] ? trace_hardirqs_on+0xd/0x10 [84434.866927] [<ffffffff81774269>] schedule+0x29/0x70 [84434.866948] [<ffffffffa06dd2ef>] wait_current_trans.isra.33+0xbf/0x120 [btrfs] [84434.866954] [<ffffffff810715c0>] ? __init_waitqueue_head+0x60/0x60 [84434.866970] [<ffffffffa06dec18>] start_transaction+0x388/0x5a0 [btrfs] [84434.866985] [<ffffffffa06db9b5>] ? transaction_kthread+0xb5/0x280 [btrfs] [84434.866999] [<ffffffffa06dee97>] btrfs_attach_transaction+0x17/0x20 [btrfs] [84434.867012] [<ffffffffa06dba9e>] transaction_kthread+0x19e/0x280 [btrfs] [84434.867026] [<ffffffffa06db900>] ? open_ctree+0x2260/0x2260 [btrfs] [84434.867030] [<ffffffff81070dad>] kthread+0xed/0x100 [84434.867035] [<ffffffff81070cc0>] ? flush_kthread_worker+0x190/0x190 [84434.867040] [<ffffffff8177ee6c>] ret_from_fork+0x7c/0xb0 [84434.867044] [<ffffffff81070cc0>] ? flush_kthread_worker+0x190/0x190 Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com> Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Chris Mason <clm@fb.com>
2013-12-15 12:43:58 +00:00
eb = btrfs_clone_extent_buffer(path->nodes[0]);
if (!eb) {
ret = -ENOMEM;
break;
}
extent_buffer_get(eb);
btrfs_tree_read_lock(eb);
btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK);
btrfs_release_path(path);
item = btrfs_item_nr(slot);
iref = btrfs_item_ptr(eb, slot, struct btrfs_inode_ref);
for (cur = 0; cur < btrfs_item_size(eb, item); cur += len) {
name_len = btrfs_inode_ref_name_len(eb, iref);
/* path must be released before calling iterate()! */
pr_debug("following ref at offset %u for inode %llu in "
"tree %llu\n", cur, found_key.objectid,
fs_root->objectid);
ret = iterate(parent, name_len,
(unsigned long)(iref + 1), eb, ctx);
if (ret)
break;
len = sizeof(*iref) + name_len;
iref = (struct btrfs_inode_ref *)((char *)iref + len);
}
btrfs_tree_read_unlock_blocking(eb);
free_extent_buffer(eb);
}
btrfs_release_path(path);
return ret;
}
static int iterate_inode_extrefs(u64 inum, struct btrfs_root *fs_root,
struct btrfs_path *path,
iterate_irefs_t *iterate, void *ctx)
{
int ret;
int slot;
u64 offset = 0;
u64 parent;
int found = 0;
struct extent_buffer *eb;
struct btrfs_inode_extref *extref;
struct extent_buffer *leaf;
u32 item_size;
u32 cur_offset;
unsigned long ptr;
while (1) {
ret = btrfs_find_one_extref(fs_root, inum, offset, path, &extref,
&offset);
if (ret < 0)
break;
if (ret) {
ret = found ? 0 : -ENOENT;
break;
}
++found;
slot = path->slots[0];
Btrfs: fix deadlock when iterating inode refs and running delayed inodes While running btrfs/004 from xfstests, after 503 iterations, dmesg reported a deadlock between tasks iterating inode refs and tasks running delayed inodes (during a transaction commit). It turns out that iterating inode refs implies doing one tree search and release all nodes in the path except the leaf node, and then passing that leaf node to btrfs_ref_to_path(), which in turn does another tree search without releasing the lock on the leaf node it received as parameter. This is a problem when other task wants to write to the btree as well and ends up updating the leaf that is read locked - the writer task locks the parent of the leaf and then blocks waiting for the leaf's lock to be released - at the same time, the task executing btrfs_ref_to_path() does a second tree search, without releasing the lock on the first leaf, and wants to access a leaf (the same or another one) that is a child of the same parent, resulting in a deadlock. The trace reported by lockdep follows. [84314.936373] INFO: task fsstress:11930 blocked for more than 120 seconds. [84314.936381] Tainted: G W O 3.12.0-fdm-btrfs-next-16+ #70 [84314.936383] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [84314.936386] fsstress D ffff8806e1bf8000 0 11930 11926 0x00000000 [84314.936393] ffff8804d6d89b78 0000000000000046 ffff8804d6d89b18 ffffffff810bd8bd [84314.936399] ffff8806e1bf8000 ffff8804d6d89fd8 ffff8804d6d89fd8 ffff8804d6d89fd8 [84314.936405] ffff880806308000 ffff8806e1bf8000 ffff8804d6d89c08 ffff8804deb8f190 [84314.936410] Call Trace: [84314.936421] [<ffffffff810bd8bd>] ? trace_hardirqs_on+0xd/0x10 [84314.936428] [<ffffffff81774269>] schedule+0x29/0x70 [84314.936451] [<ffffffffa0715bf5>] btrfs_tree_lock+0x75/0x270 [btrfs] [84314.936457] [<ffffffff810715c0>] ? __init_waitqueue_head+0x60/0x60 [84314.936470] [<ffffffffa06ba231>] btrfs_search_slot+0x7f1/0x930 [btrfs] [84314.936489] [<ffffffffa0731c2a>] ? __btrfs_run_delayed_items+0x13a/0x1e0 [btrfs] [84314.936504] [<ffffffffa06d2e1f>] btrfs_lookup_inode+0x2f/0xa0 [btrfs] [84314.936510] [<ffffffff810bd6ef>] ? trace_hardirqs_on_caller+0x1f/0x1e0 [84314.936528] [<ffffffffa073173c>] __btrfs_update_delayed_inode+0x4c/0x1d0 [btrfs] [84314.936543] [<ffffffffa0731c2a>] ? __btrfs_run_delayed_items+0x13a/0x1e0 [btrfs] [84314.936558] [<ffffffffa0731c2a>] ? __btrfs_run_delayed_items+0x13a/0x1e0 [btrfs] [84314.936573] [<ffffffffa0731c82>] __btrfs_run_delayed_items+0x192/0x1e0 [btrfs] [84314.936589] [<ffffffffa0731d03>] btrfs_run_delayed_items+0x13/0x20 [btrfs] [84314.936604] [<ffffffffa06dbcd4>] btrfs_flush_all_pending_stuffs+0x24/0x80 [btrfs] [84314.936620] [<ffffffffa06ddc13>] btrfs_commit_transaction+0x223/0xa20 [btrfs] [84314.936630] [<ffffffffa06ae5ae>] btrfs_sync_fs+0x6e/0x110 [btrfs] [84314.936635] [<ffffffff811d0b50>] ? __sync_filesystem+0x60/0x60 [84314.936639] [<ffffffff811d0b50>] ? __sync_filesystem+0x60/0x60 [84314.936643] [<ffffffff811d0b70>] sync_fs_one_sb+0x20/0x30 [84314.936648] [<ffffffff811a3541>] iterate_supers+0xf1/0x100 [84314.936652] [<ffffffff811d0c45>] sys_sync+0x55/0x90 [84314.936658] [<ffffffff8177ef12>] system_call_fastpath+0x16/0x1b [84314.936660] INFO: lockdep is turned off. [84314.936663] INFO: task btrfs:11955 blocked for more than 120 seconds. [84314.936666] Tainted: G W O 3.12.0-fdm-btrfs-next-16+ #70 [84314.936668] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [84314.936670] btrfs D ffff880541729a88 0 11955 11608 0x00000000 [84314.936674] ffff880541729a38 0000000000000046 ffff8805417299d8 ffffffff810bd8bd [84314.936680] ffff88075430c8a0 ffff880541729fd8 ffff880541729fd8 ffff880541729fd8 [84314.936685] ffffffff81c104e0 ffff88075430c8a0 ffff8804de8b00b8 ffff8804de8b0000 [84314.936690] Call Trace: [84314.936695] [<ffffffff810bd8bd>] ? trace_hardirqs_on+0xd/0x10 [84314.936700] [<ffffffff81774269>] schedule+0x29/0x70 [84314.936717] [<ffffffffa0715815>] btrfs_tree_read_lock+0xd5/0x140 [btrfs] [84314.936721] [<ffffffff810715c0>] ? __init_waitqueue_head+0x60/0x60 [84314.936733] [<ffffffffa06ba201>] btrfs_search_slot+0x7c1/0x930 [btrfs] [84314.936746] [<ffffffffa06bd505>] btrfs_find_item+0x55/0x160 [btrfs] [84314.936763] [<ffffffffa06ff689>] ? free_extent_buffer+0x49/0xc0 [btrfs] [84314.936780] [<ffffffffa073c9ca>] btrfs_ref_to_path+0xba/0x1e0 [btrfs] [84314.936797] [<ffffffffa06f9719>] ? release_extent_buffer+0xb9/0xe0 [btrfs] [84314.936813] [<ffffffffa06ff689>] ? free_extent_buffer+0x49/0xc0 [btrfs] [84314.936830] [<ffffffffa073cb50>] inode_to_path+0x60/0xd0 [btrfs] [84314.936846] [<ffffffffa073d365>] paths_from_inode+0x115/0x3c0 [btrfs] [84314.936851] [<ffffffff8118dd44>] ? kmem_cache_alloc_trace+0x114/0x200 [84314.936868] [<ffffffffa0714494>] btrfs_ioctl+0xf14/0x2030 [btrfs] [84314.936873] [<ffffffff817762db>] ? _raw_spin_unlock+0x2b/0x50 [84314.936877] [<ffffffff8116598f>] ? handle_mm_fault+0x34f/0xb00 [84314.936882] [<ffffffff81075563>] ? up_read+0x23/0x40 [84314.936886] [<ffffffff8177a41c>] ? __do_page_fault+0x20c/0x5a0 [84314.936892] [<ffffffff811b2946>] do_vfs_ioctl+0x96/0x570 [84314.936896] [<ffffffff81776e23>] ? error_sti+0x5/0x6 [84314.936901] [<ffffffff810b71e8>] ? trace_hardirqs_off_caller+0x28/0xd0 [84314.936906] [<ffffffff81776a09>] ? retint_swapgs+0xe/0x13 [84314.936910] [<ffffffff811b2eb1>] SyS_ioctl+0x91/0xb0 [84314.936915] [<ffffffff813eecde>] ? trace_hardirqs_on_thunk+0x3a/0x3f [84314.936920] [<ffffffff8177ef12>] system_call_fastpath+0x16/0x1b [84314.936922] INFO: lockdep is turned off. [84434.866873] INFO: task btrfs-transacti:11921 blocked for more than 120 seconds. [84434.866881] Tainted: G W O 3.12.0-fdm-btrfs-next-16+ #70 [84434.866883] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [84434.866886] btrfs-transacti D ffff880755b6a478 0 11921 2 0x00000000 [84434.866893] ffff8800735b9ce8 0000000000000046 ffff8800735b9c88 ffffffff810bd8bd [84434.866899] ffff8805a1b848a0 ffff8800735b9fd8 ffff8800735b9fd8 ffff8800735b9fd8 [84434.866904] ffffffff81c104e0 ffff8805a1b848a0 ffff880755b6a478 ffff8804cece78f0 [84434.866910] Call Trace: [84434.866920] [<ffffffff810bd8bd>] ? trace_hardirqs_on+0xd/0x10 [84434.866927] [<ffffffff81774269>] schedule+0x29/0x70 [84434.866948] [<ffffffffa06dd2ef>] wait_current_trans.isra.33+0xbf/0x120 [btrfs] [84434.866954] [<ffffffff810715c0>] ? __init_waitqueue_head+0x60/0x60 [84434.866970] [<ffffffffa06dec18>] start_transaction+0x388/0x5a0 [btrfs] [84434.866985] [<ffffffffa06db9b5>] ? transaction_kthread+0xb5/0x280 [btrfs] [84434.866999] [<ffffffffa06dee97>] btrfs_attach_transaction+0x17/0x20 [btrfs] [84434.867012] [<ffffffffa06dba9e>] transaction_kthread+0x19e/0x280 [btrfs] [84434.867026] [<ffffffffa06db900>] ? open_ctree+0x2260/0x2260 [btrfs] [84434.867030] [<ffffffff81070dad>] kthread+0xed/0x100 [84434.867035] [<ffffffff81070cc0>] ? flush_kthread_worker+0x190/0x190 [84434.867040] [<ffffffff8177ee6c>] ret_from_fork+0x7c/0xb0 [84434.867044] [<ffffffff81070cc0>] ? flush_kthread_worker+0x190/0x190 Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com> Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Chris Mason <clm@fb.com>
2013-12-15 12:43:58 +00:00
eb = btrfs_clone_extent_buffer(path->nodes[0]);
if (!eb) {
ret = -ENOMEM;
break;
}
extent_buffer_get(eb);
btrfs_tree_read_lock(eb);
btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK);
btrfs_release_path(path);
leaf = path->nodes[0];
item_size = btrfs_item_size_nr(leaf, slot);
ptr = btrfs_item_ptr_offset(leaf, slot);
cur_offset = 0;
while (cur_offset < item_size) {
u32 name_len;
extref = (struct btrfs_inode_extref *)(ptr + cur_offset);
parent = btrfs_inode_extref_parent(eb, extref);
name_len = btrfs_inode_extref_name_len(eb, extref);
ret = iterate(parent, name_len,
(unsigned long)&extref->name, eb, ctx);
if (ret)
break;
cur_offset += btrfs_inode_extref_name_len(leaf, extref);
cur_offset += sizeof(*extref);
}
btrfs_tree_read_unlock_blocking(eb);
free_extent_buffer(eb);
offset++;
}
btrfs_release_path(path);
return ret;
}
static int iterate_irefs(u64 inum, struct btrfs_root *fs_root,
struct btrfs_path *path, iterate_irefs_t *iterate,
void *ctx)
{
int ret;
int found_refs = 0;
ret = iterate_inode_refs(inum, fs_root, path, iterate, ctx);
if (!ret)
++found_refs;
else if (ret != -ENOENT)
return ret;
ret = iterate_inode_extrefs(inum, fs_root, path, iterate, ctx);
if (ret == -ENOENT && found_refs)
return 0;
return ret;
}
/*
* returns 0 if the path could be dumped (probably truncated)
* returns <0 in case of an error
*/
static int inode_to_path(u64 inum, u32 name_len, unsigned long name_off,
struct extent_buffer *eb, void *ctx)
{
struct inode_fs_paths *ipath = ctx;
char *fspath;
char *fspath_min;
int i = ipath->fspath->elem_cnt;
const int s_ptr = sizeof(char *);
u32 bytes_left;
bytes_left = ipath->fspath->bytes_left > s_ptr ?
ipath->fspath->bytes_left - s_ptr : 0;
fspath_min = (char *)ipath->fspath->val + (i + 1) * s_ptr;
fspath = btrfs_ref_to_path(ipath->fs_root, ipath->btrfs_path, name_len,
name_off, eb, inum, fspath_min, bytes_left);
if (IS_ERR(fspath))
return PTR_ERR(fspath);
if (fspath > fspath_min) {
ipath->fspath->val[i] = (u64)(unsigned long)fspath;
++ipath->fspath->elem_cnt;
ipath->fspath->bytes_left = fspath - fspath_min;
} else {
++ipath->fspath->elem_missed;
ipath->fspath->bytes_missing += fspath_min - fspath;
ipath->fspath->bytes_left = 0;
}
return 0;
}
/*
* this dumps all file system paths to the inode into the ipath struct, provided
* is has been created large enough. each path is zero-terminated and accessed
* from ipath->fspath->val[i].
* when it returns, there are ipath->fspath->elem_cnt number of paths available
* in ipath->fspath->val[]. when the allocated space wasn't sufficient, the
* number of missed paths in recored in ipath->fspath->elem_missed, otherwise,
* it's zero. ipath->fspath->bytes_missing holds the number of bytes that would
* have been needed to return all paths.
*/
int paths_from_inode(u64 inum, struct inode_fs_paths *ipath)
{
return iterate_irefs(inum, ipath->fs_root, ipath->btrfs_path,
inode_to_path, ipath);
}
struct btrfs_data_container *init_data_container(u32 total_bytes)
{
struct btrfs_data_container *data;
size_t alloc_bytes;
alloc_bytes = max_t(size_t, total_bytes, sizeof(*data));
data = vmalloc(alloc_bytes);
if (!data)
return ERR_PTR(-ENOMEM);
if (total_bytes >= sizeof(*data)) {
data->bytes_left = total_bytes - sizeof(*data);
data->bytes_missing = 0;
} else {
data->bytes_missing = sizeof(*data) - total_bytes;
data->bytes_left = 0;
}
data->elem_cnt = 0;
data->elem_missed = 0;
return data;
}
/*
* allocates space to return multiple file system paths for an inode.
* total_bytes to allocate are passed, note that space usable for actual path
* information will be total_bytes - sizeof(struct inode_fs_paths).
* the returned pointer must be freed with free_ipath() in the end.
*/
struct inode_fs_paths *init_ipath(s32 total_bytes, struct btrfs_root *fs_root,
struct btrfs_path *path)
{
struct inode_fs_paths *ifp;
struct btrfs_data_container *fspath;
fspath = init_data_container(total_bytes);
if (IS_ERR(fspath))
return (void *)fspath;
ifp = kmalloc(sizeof(*ifp), GFP_NOFS);
if (!ifp) {
kfree(fspath);
return ERR_PTR(-ENOMEM);
}
ifp->btrfs_path = path;
ifp->fspath = fspath;
ifp->fs_root = fs_root;
return ifp;
}
void free_ipath(struct inode_fs_paths *ipath)
{
if (!ipath)
return;
vfree(ipath->fspath);
kfree(ipath);
}