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linux/fs/gfs2/log.c
Bob Peterson 0efc4976e3 gfs2: bypass log flush if the journal is not live 
Patch fe3e397668 ("gfs2: Rework the log space allocation logic")
changed gfs2_log_flush to reserve a set of journal blocks in case no
transaction is active.  However, gfs2_log_flush also gets called in
cases where we don't have an active journal, for example, for spectator
mounts.  In that case, trying to reserve blocks would sleep forever, but
we want gfs2_log_flush to be a no-op instead.

Fixes: fe3e397668 ("gfs2: Rework the log space allocation logic")
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
2021-03-12 15:52:48 +01:00

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// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
* Copyright (C) 2004-2007 Red Hat, Inc. All rights reserved.
*/
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/completion.h>
#include <linux/buffer_head.h>
#include <linux/gfs2_ondisk.h>
#include <linux/crc32.h>
#include <linux/crc32c.h>
#include <linux/delay.h>
#include <linux/kthread.h>
#include <linux/freezer.h>
#include <linux/bio.h>
#include <linux/blkdev.h>
#include <linux/writeback.h>
#include <linux/list_sort.h>
#include "gfs2.h"
#include "incore.h"
#include "bmap.h"
#include "glock.h"
#include "log.h"
#include "lops.h"
#include "meta_io.h"
#include "util.h"
#include "dir.h"
#include "trace_gfs2.h"
#include "trans.h"
static void gfs2_log_shutdown(struct gfs2_sbd *sdp);
/**
* gfs2_struct2blk - compute stuff
* @sdp: the filesystem
* @nstruct: the number of structures
*
* Compute the number of log descriptor blocks needed to hold a certain number
* of structures of a certain size.
*
* Returns: the number of blocks needed (minimum is always 1)
*/
unsigned int gfs2_struct2blk(struct gfs2_sbd *sdp, unsigned int nstruct)
{
unsigned int blks;
unsigned int first, second;
/* The initial struct gfs2_log_descriptor block */
blks = 1;
first = sdp->sd_ldptrs;
if (nstruct > first) {
/* Subsequent struct gfs2_meta_header blocks */
second = sdp->sd_inptrs;
blks += DIV_ROUND_UP(nstruct - first, second);
}
return blks;
}
/**
* gfs2_remove_from_ail - Remove an entry from the ail lists, updating counters
* @mapping: The associated mapping (maybe NULL)
* @bd: The gfs2_bufdata to remove
*
* The ail lock _must_ be held when calling this function
*
*/
void gfs2_remove_from_ail(struct gfs2_bufdata *bd)
{
bd->bd_tr = NULL;
list_del_init(&bd->bd_ail_st_list);
list_del_init(&bd->bd_ail_gl_list);
atomic_dec(&bd->bd_gl->gl_ail_count);
brelse(bd->bd_bh);
}
/**
* gfs2_ail1_start_one - Start I/O on a part of the AIL
* @sdp: the filesystem
* @wbc: The writeback control structure
* @ai: The ail structure
*
*/
static int gfs2_ail1_start_one(struct gfs2_sbd *sdp,
struct writeback_control *wbc,
struct gfs2_trans *tr, struct blk_plug *plug)
__releases(&sdp->sd_ail_lock)
__acquires(&sdp->sd_ail_lock)
{
struct gfs2_glock *gl = NULL;
struct address_space *mapping;
struct gfs2_bufdata *bd, *s;
struct buffer_head *bh;
int ret = 0;
list_for_each_entry_safe_reverse(bd, s, &tr->tr_ail1_list, bd_ail_st_list) {
bh = bd->bd_bh;
gfs2_assert(sdp, bd->bd_tr == tr);
if (!buffer_busy(bh)) {
if (buffer_uptodate(bh)) {
list_move(&bd->bd_ail_st_list,
&tr->tr_ail2_list);
continue;
}
if (!cmpxchg(&sdp->sd_log_error, 0, -EIO)) {
gfs2_io_error_bh(sdp, bh);
gfs2_withdraw_delayed(sdp);
}
}
if (gfs2_withdrawn(sdp)) {
gfs2_remove_from_ail(bd);
continue;
}
if (!buffer_dirty(bh))
continue;
if (gl == bd->bd_gl)
continue;
gl = bd->bd_gl;
list_move(&bd->bd_ail_st_list, &tr->tr_ail1_list);
mapping = bh->b_page->mapping;
if (!mapping)
continue;
spin_unlock(&sdp->sd_ail_lock);
ret = generic_writepages(mapping, wbc);
if (need_resched()) {
blk_finish_plug(plug);
cond_resched();
blk_start_plug(plug);
}
spin_lock(&sdp->sd_ail_lock);
if (ret == -ENODATA) /* if a jdata write into a new hole */
ret = 0; /* ignore it */
if (ret || wbc->nr_to_write <= 0)
break;
return -EBUSY;
}
return ret;
}
static void dump_ail_list(struct gfs2_sbd *sdp)
{
struct gfs2_trans *tr;
struct gfs2_bufdata *bd;
struct buffer_head *bh;
list_for_each_entry_reverse(tr, &sdp->sd_ail1_list, tr_list) {
list_for_each_entry_reverse(bd, &tr->tr_ail1_list,
bd_ail_st_list) {
bh = bd->bd_bh;
fs_err(sdp, "bd %p: blk:0x%llx bh=%p ", bd,
(unsigned long long)bd->bd_blkno, bh);
if (!bh) {
fs_err(sdp, "\n");
continue;
}
fs_err(sdp, "0x%llx up2:%d dirt:%d lkd:%d req:%d "
"map:%d new:%d ar:%d aw:%d delay:%d "
"io err:%d unwritten:%d dfr:%d pin:%d esc:%d\n",
(unsigned long long)bh->b_blocknr,
buffer_uptodate(bh), buffer_dirty(bh),
buffer_locked(bh), buffer_req(bh),
buffer_mapped(bh), buffer_new(bh),
buffer_async_read(bh), buffer_async_write(bh),
buffer_delay(bh), buffer_write_io_error(bh),
buffer_unwritten(bh),
buffer_defer_completion(bh),
buffer_pinned(bh), buffer_escaped(bh));
}
}
}
/**
* gfs2_ail1_flush - start writeback of some ail1 entries
* @sdp: The super block
* @wbc: The writeback control structure
*
* Writes back some ail1 entries, according to the limits in the
* writeback control structure
*/
void gfs2_ail1_flush(struct gfs2_sbd *sdp, struct writeback_control *wbc)
{
struct list_head *head = &sdp->sd_ail1_list;
struct gfs2_trans *tr;
struct blk_plug plug;
int ret;
unsigned long flush_start = jiffies;
trace_gfs2_ail_flush(sdp, wbc, 1);
blk_start_plug(&plug);
spin_lock(&sdp->sd_ail_lock);
restart:
ret = 0;
if (time_after(jiffies, flush_start + (HZ * 600))) {
fs_err(sdp, "Error: In %s for ten minutes! t=%d\n",
__func__, current->journal_info ? 1 : 0);
dump_ail_list(sdp);
goto out;
}
list_for_each_entry_reverse(tr, head, tr_list) {
if (wbc->nr_to_write <= 0)
break;
ret = gfs2_ail1_start_one(sdp, wbc, tr, &plug);
if (ret) {
if (ret == -EBUSY)
goto restart;
break;
}
}
out:
spin_unlock(&sdp->sd_ail_lock);
blk_finish_plug(&plug);
if (ret) {
gfs2_lm(sdp, "gfs2_ail1_start_one (generic_writepages) "
"returned: %d\n", ret);
gfs2_withdraw(sdp);
}
trace_gfs2_ail_flush(sdp, wbc, 0);
}
/**
* gfs2_ail1_start - start writeback of all ail1 entries
* @sdp: The superblock
*/
static void gfs2_ail1_start(struct gfs2_sbd *sdp)
{
struct writeback_control wbc = {
.sync_mode = WB_SYNC_NONE,
.nr_to_write = LONG_MAX,
.range_start = 0,
.range_end = LLONG_MAX,
};
return gfs2_ail1_flush(sdp, &wbc);
}
static void gfs2_log_update_flush_tail(struct gfs2_sbd *sdp)
{
unsigned int new_flush_tail = sdp->sd_log_head;
struct gfs2_trans *tr;
if (!list_empty(&sdp->sd_ail1_list)) {
tr = list_last_entry(&sdp->sd_ail1_list,
struct gfs2_trans, tr_list);
new_flush_tail = tr->tr_first;
}
sdp->sd_log_flush_tail = new_flush_tail;
}
static void gfs2_log_update_head(struct gfs2_sbd *sdp)
{
unsigned int new_head = sdp->sd_log_flush_head;
if (sdp->sd_log_flush_tail == sdp->sd_log_head)
sdp->sd_log_flush_tail = new_head;
sdp->sd_log_head = new_head;
}
/**
* gfs2_ail_empty_tr - empty one of the ail lists of a transaction
*/
static void gfs2_ail_empty_tr(struct gfs2_sbd *sdp, struct gfs2_trans *tr,
struct list_head *head)
{
struct gfs2_bufdata *bd;
while (!list_empty(head)) {
bd = list_first_entry(head, struct gfs2_bufdata,
bd_ail_st_list);
gfs2_assert(sdp, bd->bd_tr == tr);
gfs2_remove_from_ail(bd);
}
}
/**
* gfs2_ail1_empty_one - Check whether or not a trans in the AIL has been synced
* @sdp: the filesystem
* @tr: the transaction
* @max_revokes: If nonzero, issue revokes for the bd items for written buffers
*
* returns: the transaction's count of remaining active items
*/
static int gfs2_ail1_empty_one(struct gfs2_sbd *sdp, struct gfs2_trans *tr,
int *max_revokes)
{
struct gfs2_bufdata *bd, *s;
struct buffer_head *bh;
int active_count = 0;
list_for_each_entry_safe_reverse(bd, s, &tr->tr_ail1_list,
bd_ail_st_list) {
bh = bd->bd_bh;
gfs2_assert(sdp, bd->bd_tr == tr);
/*
* If another process flagged an io error, e.g. writing to the
* journal, error all other bhs and move them off the ail1 to
* prevent a tight loop when unmount tries to flush ail1,
* regardless of whether they're still busy. If no outside
* errors were found and the buffer is busy, move to the next.
* If the ail buffer is not busy and caught an error, flag it
* for others.
*/
if (!sdp->sd_log_error && buffer_busy(bh)) {
active_count++;
continue;
}
if (!buffer_uptodate(bh) &&
!cmpxchg(&sdp->sd_log_error, 0, -EIO)) {
gfs2_io_error_bh(sdp, bh);
gfs2_withdraw_delayed(sdp);
}
/*
* If we have space for revokes and the bd is no longer on any
* buf list, we can just add a revoke for it immediately and
* avoid having to put it on the ail2 list, where it would need
* to be revoked later.
*/
if (*max_revokes && list_empty(&bd->bd_list)) {
gfs2_add_revoke(sdp, bd);
(*max_revokes)--;
continue;
}
list_move(&bd->bd_ail_st_list, &tr->tr_ail2_list);
}
return active_count;
}
/**
* gfs2_ail1_empty - Try to empty the ail1 lists
* @sdp: The superblock
* @max_revokes: If non-zero, add revokes where appropriate
*
* Tries to empty the ail1 lists, starting with the oldest first
*/
static int gfs2_ail1_empty(struct gfs2_sbd *sdp, int max_revokes)
{
struct gfs2_trans *tr, *s;
int oldest_tr = 1;
int ret;
spin_lock(&sdp->sd_ail_lock);
list_for_each_entry_safe_reverse(tr, s, &sdp->sd_ail1_list, tr_list) {
if (!gfs2_ail1_empty_one(sdp, tr, &max_revokes) && oldest_tr)
list_move(&tr->tr_list, &sdp->sd_ail2_list);
else
oldest_tr = 0;
}
gfs2_log_update_flush_tail(sdp);
ret = list_empty(&sdp->sd_ail1_list);
spin_unlock(&sdp->sd_ail_lock);
if (test_bit(SDF_WITHDRAWING, &sdp->sd_flags)) {
gfs2_lm(sdp, "fatal: I/O error(s)\n");
gfs2_withdraw(sdp);
}
return ret;
}
static void gfs2_ail1_wait(struct gfs2_sbd *sdp)
{
struct gfs2_trans *tr;
struct gfs2_bufdata *bd;
struct buffer_head *bh;
spin_lock(&sdp->sd_ail_lock);
list_for_each_entry_reverse(tr, &sdp->sd_ail1_list, tr_list) {
list_for_each_entry(bd, &tr->tr_ail1_list, bd_ail_st_list) {
bh = bd->bd_bh;
if (!buffer_locked(bh))
continue;
get_bh(bh);
spin_unlock(&sdp->sd_ail_lock);
wait_on_buffer(bh);
brelse(bh);
return;
}
}
spin_unlock(&sdp->sd_ail_lock);
}
static void __ail2_empty(struct gfs2_sbd *sdp, struct gfs2_trans *tr)
{
gfs2_ail_empty_tr(sdp, tr, &tr->tr_ail2_list);
list_del(&tr->tr_list);
gfs2_assert_warn(sdp, list_empty(&tr->tr_ail1_list));
gfs2_assert_warn(sdp, list_empty(&tr->tr_ail2_list));
gfs2_trans_free(sdp, tr);
}
static void ail2_empty(struct gfs2_sbd *sdp, unsigned int new_tail)
{
struct list_head *ail2_list = &sdp->sd_ail2_list;
unsigned int old_tail = sdp->sd_log_tail;
struct gfs2_trans *tr, *safe;
spin_lock(&sdp->sd_ail_lock);
if (old_tail <= new_tail) {
list_for_each_entry_safe(tr, safe, ail2_list, tr_list) {
if (old_tail <= tr->tr_first && tr->tr_first < new_tail)
__ail2_empty(sdp, tr);
}
} else {
list_for_each_entry_safe(tr, safe, ail2_list, tr_list) {
if (old_tail <= tr->tr_first || tr->tr_first < new_tail)
__ail2_empty(sdp, tr);
}
}
spin_unlock(&sdp->sd_ail_lock);
}
/**
* gfs2_log_is_empty - Check if the log is empty
* @sdp: The GFS2 superblock
*/
bool gfs2_log_is_empty(struct gfs2_sbd *sdp) {
return atomic_read(&sdp->sd_log_blks_free) == sdp->sd_jdesc->jd_blocks;
}
static bool __gfs2_log_try_reserve_revokes(struct gfs2_sbd *sdp, unsigned int revokes)
{
unsigned int available;
available = atomic_read(&sdp->sd_log_revokes_available);
while (available >= revokes) {
if (atomic_try_cmpxchg(&sdp->sd_log_revokes_available,
&available, available - revokes))
return true;
}
return false;
}
/**
* gfs2_log_release_revokes - Release a given number of revokes
* @sdp: The GFS2 superblock
* @revokes: The number of revokes to release
*
* sdp->sd_log_flush_lock must be held.
*/
void gfs2_log_release_revokes(struct gfs2_sbd *sdp, unsigned int revokes)
{
if (revokes)
atomic_add(revokes, &sdp->sd_log_revokes_available);
}
/**
* gfs2_log_release - Release a given number of log blocks
* @sdp: The GFS2 superblock
* @blks: The number of blocks
*
*/
void gfs2_log_release(struct gfs2_sbd *sdp, unsigned int blks)
{
atomic_add(blks, &sdp->sd_log_blks_free);
trace_gfs2_log_blocks(sdp, blks);
gfs2_assert_withdraw(sdp, atomic_read(&sdp->sd_log_blks_free) <=
sdp->sd_jdesc->jd_blocks);
if (atomic_read(&sdp->sd_log_blks_needed))
wake_up(&sdp->sd_log_waitq);
}
/**
* __gfs2_log_try_reserve - Try to make a log reservation
* @sdp: The GFS2 superblock
* @blks: The number of blocks to reserve
* @taboo_blks: The number of blocks to leave free
*
* Try to do the same as __gfs2_log_reserve(), but fail if no more log
* space is immediately available.
*/
static bool __gfs2_log_try_reserve(struct gfs2_sbd *sdp, unsigned int blks,
unsigned int taboo_blks)
{
unsigned wanted = blks + taboo_blks;
unsigned int free_blocks;
free_blocks = atomic_read(&sdp->sd_log_blks_free);
while (free_blocks >= wanted) {
if (atomic_try_cmpxchg(&sdp->sd_log_blks_free, &free_blocks,
free_blocks - blks)) {
trace_gfs2_log_blocks(sdp, -blks);
return true;
}
}
return false;
}
/**
* __gfs2_log_reserve - Make a log reservation
* @sdp: The GFS2 superblock
* @blks: The number of blocks to reserve
* @taboo_blks: The number of blocks to leave free
*
* @taboo_blks is set to 0 for logd, and to GFS2_LOG_FLUSH_MIN_BLOCKS
* for all other processes. This ensures that when the log is almost full,
* logd will still be able to call gfs2_log_flush one more time without
* blocking, which will advance the tail and make some more log space
* available.
*
* We no longer flush the log here, instead we wake up logd to do that
* for us. To avoid the thundering herd and to ensure that we deal fairly
* with queued waiters, we use an exclusive wait. This means that when we
* get woken with enough journal space to get our reservation, we need to
* wake the next waiter on the list.
*/
static void __gfs2_log_reserve(struct gfs2_sbd *sdp, unsigned int blks,
unsigned int taboo_blks)
{
unsigned wanted = blks + taboo_blks;
unsigned int free_blocks;
atomic_add(blks, &sdp->sd_log_blks_needed);
for (;;) {
if (current != sdp->sd_logd_process)
wake_up(&sdp->sd_logd_waitq);
io_wait_event(sdp->sd_log_waitq,
(free_blocks = atomic_read(&sdp->sd_log_blks_free),
free_blocks >= wanted));
do {
if (atomic_try_cmpxchg(&sdp->sd_log_blks_free,
&free_blocks,
free_blocks - blks))
goto reserved;
} while (free_blocks >= wanted);
}
reserved:
trace_gfs2_log_blocks(sdp, -blks);
if (atomic_sub_return(blks, &sdp->sd_log_blks_needed))
wake_up(&sdp->sd_log_waitq);
}
/**
* gfs2_log_try_reserve - Try to make a log reservation
* @sdp: The GFS2 superblock
* @tr: The transaction
* @extra_revokes: The number of additional revokes reserved (output)
*
* This is similar to gfs2_log_reserve, but sdp->sd_log_flush_lock must be
* held for correct revoke accounting.
*/
bool gfs2_log_try_reserve(struct gfs2_sbd *sdp, struct gfs2_trans *tr,
unsigned int *extra_revokes)
{
unsigned int blks = tr->tr_reserved;
unsigned int revokes = tr->tr_revokes;
unsigned int revoke_blks = 0;
*extra_revokes = 0;
if (revokes && !__gfs2_log_try_reserve_revokes(sdp, revokes)) {
revoke_blks = DIV_ROUND_UP(revokes, sdp->sd_inptrs);
*extra_revokes = revoke_blks * sdp->sd_inptrs - revokes;
blks += revoke_blks;
}
if (!blks)
return true;
if (__gfs2_log_try_reserve(sdp, blks, GFS2_LOG_FLUSH_MIN_BLOCKS))
return true;
if (!revoke_blks)
gfs2_log_release_revokes(sdp, revokes);
return false;
}
/**
* gfs2_log_reserve - Make a log reservation
* @sdp: The GFS2 superblock
* @tr: The transaction
* @extra_revokes: The number of additional revokes reserved (output)
*
* sdp->sd_log_flush_lock must not be held.
*/
void gfs2_log_reserve(struct gfs2_sbd *sdp, struct gfs2_trans *tr,
unsigned int *extra_revokes)
{
unsigned int blks = tr->tr_reserved;
unsigned int revokes = tr->tr_revokes;
unsigned int revoke_blks = 0;
*extra_revokes = 0;
if (revokes) {
revoke_blks = DIV_ROUND_UP(revokes, sdp->sd_inptrs);
*extra_revokes = revoke_blks * sdp->sd_inptrs - revokes;
blks += revoke_blks;
}
__gfs2_log_reserve(sdp, blks, GFS2_LOG_FLUSH_MIN_BLOCKS);
}
/**
* log_distance - Compute distance between two journal blocks
* @sdp: The GFS2 superblock
* @newer: The most recent journal block of the pair
* @older: The older journal block of the pair
*
* Compute the distance (in the journal direction) between two
* blocks in the journal
*
* Returns: the distance in blocks
*/
static inline unsigned int log_distance(struct gfs2_sbd *sdp, unsigned int newer,
unsigned int older)
{
int dist;
dist = newer - older;
if (dist < 0)
dist += sdp->sd_jdesc->jd_blocks;
return dist;
}
/**
* calc_reserved - Calculate the number of blocks to keep reserved
* @sdp: The GFS2 superblock
*
* This is complex. We need to reserve room for all our currently used
* metadata blocks (e.g. normal file I/O rewriting file time stamps) and
* all our journaled data blocks for journaled files (e.g. files in the
* meta_fs like rindex, or files for which chattr +j was done.)
* If we don't reserve enough space, corruption will follow.
*
* We can have metadata blocks and jdata blocks in the same journal. Each
* type gets its own log descriptor, for which we need to reserve a block.
* In fact, each type has the potential for needing more than one log descriptor
* in cases where we have more blocks than will fit in a log descriptor.
* Metadata journal entries take up half the space of journaled buffer entries.
*
* Also, we need to reserve blocks for revoke journal entries and one for an
* overall header for the lot.
*
* Returns: the number of blocks reserved
*/
static unsigned int calc_reserved(struct gfs2_sbd *sdp)
{
unsigned int reserved = GFS2_LOG_FLUSH_MIN_BLOCKS;
unsigned int blocks;
struct gfs2_trans *tr = sdp->sd_log_tr;
if (tr) {
blocks = tr->tr_num_buf_new - tr->tr_num_buf_rm;
reserved += blocks + DIV_ROUND_UP(blocks, buf_limit(sdp));
blocks = tr->tr_num_databuf_new - tr->tr_num_databuf_rm;
reserved += blocks + DIV_ROUND_UP(blocks, databuf_limit(sdp));
}
return reserved;
}
static void log_pull_tail(struct gfs2_sbd *sdp)
{
unsigned int new_tail = sdp->sd_log_flush_tail;
unsigned int dist;
if (new_tail == sdp->sd_log_tail)
return;
dist = log_distance(sdp, new_tail, sdp->sd_log_tail);
ail2_empty(sdp, new_tail);
gfs2_log_release(sdp, dist);
sdp->sd_log_tail = new_tail;
}
void log_flush_wait(struct gfs2_sbd *sdp)
{
DEFINE_WAIT(wait);
if (atomic_read(&sdp->sd_log_in_flight)) {
do {
prepare_to_wait(&sdp->sd_log_flush_wait, &wait,
TASK_UNINTERRUPTIBLE);
if (atomic_read(&sdp->sd_log_in_flight))
io_schedule();
} while(atomic_read(&sdp->sd_log_in_flight));
finish_wait(&sdp->sd_log_flush_wait, &wait);
}
}
static int ip_cmp(void *priv, struct list_head *a, struct list_head *b)
{
struct gfs2_inode *ipa, *ipb;
ipa = list_entry(a, struct gfs2_inode, i_ordered);
ipb = list_entry(b, struct gfs2_inode, i_ordered);
if (ipa->i_no_addr < ipb->i_no_addr)
return -1;
if (ipa->i_no_addr > ipb->i_no_addr)
return 1;
return 0;
}
static void __ordered_del_inode(struct gfs2_inode *ip)
{
if (!list_empty(&ip->i_ordered))
list_del_init(&ip->i_ordered);
}
static void gfs2_ordered_write(struct gfs2_sbd *sdp)
{
struct gfs2_inode *ip;
LIST_HEAD(written);
spin_lock(&sdp->sd_ordered_lock);
list_sort(NULL, &sdp->sd_log_ordered, &ip_cmp);
while (!list_empty(&sdp->sd_log_ordered)) {
ip = list_first_entry(&sdp->sd_log_ordered, struct gfs2_inode, i_ordered);
if (ip->i_inode.i_mapping->nrpages == 0) {
__ordered_del_inode(ip);
continue;
}
list_move(&ip->i_ordered, &written);
spin_unlock(&sdp->sd_ordered_lock);
filemap_fdatawrite(ip->i_inode.i_mapping);
spin_lock(&sdp->sd_ordered_lock);
}
list_splice(&written, &sdp->sd_log_ordered);
spin_unlock(&sdp->sd_ordered_lock);
}
static void gfs2_ordered_wait(struct gfs2_sbd *sdp)
{
struct gfs2_inode *ip;
spin_lock(&sdp->sd_ordered_lock);
while (!list_empty(&sdp->sd_log_ordered)) {
ip = list_first_entry(&sdp->sd_log_ordered, struct gfs2_inode, i_ordered);
__ordered_del_inode(ip);
if (ip->i_inode.i_mapping->nrpages == 0)
continue;
spin_unlock(&sdp->sd_ordered_lock);
filemap_fdatawait(ip->i_inode.i_mapping);
spin_lock(&sdp->sd_ordered_lock);
}
spin_unlock(&sdp->sd_ordered_lock);
}
void gfs2_ordered_del_inode(struct gfs2_inode *ip)
{
struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
spin_lock(&sdp->sd_ordered_lock);
__ordered_del_inode(ip);
spin_unlock(&sdp->sd_ordered_lock);
}
void gfs2_add_revoke(struct gfs2_sbd *sdp, struct gfs2_bufdata *bd)
{
struct buffer_head *bh = bd->bd_bh;
struct gfs2_glock *gl = bd->bd_gl;
sdp->sd_log_num_revoke++;
if (atomic_inc_return(&gl->gl_revokes) == 1)
gfs2_glock_hold(gl);
bh->b_private = NULL;
bd->bd_blkno = bh->b_blocknr;
gfs2_remove_from_ail(bd); /* drops ref on bh */
bd->bd_bh = NULL;
set_bit(GLF_LFLUSH, &gl->gl_flags);
list_add(&bd->bd_list, &sdp->sd_log_revokes);
}
void gfs2_glock_remove_revoke(struct gfs2_glock *gl)
{
if (atomic_dec_return(&gl->gl_revokes) == 0) {
clear_bit(GLF_LFLUSH, &gl->gl_flags);
gfs2_glock_queue_put(gl);
}
}
/**
* gfs2_flush_revokes - Add as many revokes to the system transaction as we can
* @sdp: The GFS2 superblock
*
* Our usual strategy is to defer writing revokes as much as we can in the hope
* that we'll eventually overwrite the journal, which will make those revokes
* go away. This changes when we flush the log: at that point, there will
* likely be some left-over space in the last revoke block of that transaction.
* We can fill that space with additional revokes for blocks that have already
* been written back. This will basically come at no cost now, and will save
* us from having to keep track of those blocks on the AIL2 list later.
*/
void gfs2_flush_revokes(struct gfs2_sbd *sdp)
{
/* number of revokes we still have room for */
unsigned int max_revokes = atomic_read(&sdp->sd_log_revokes_available);
gfs2_log_lock(sdp);
gfs2_ail1_empty(sdp, max_revokes);
gfs2_log_unlock(sdp);
}
/**
* gfs2_write_log_header - Write a journal log header buffer at lblock
* @sdp: The GFS2 superblock
* @jd: journal descriptor of the journal to which we are writing
* @seq: sequence number
* @tail: tail of the log
* @lblock: value for lh_blkno (block number relative to start of journal)
* @flags: log header flags GFS2_LOG_HEAD_*
* @op_flags: flags to pass to the bio
*
* Returns: the initialized log buffer descriptor
*/
void gfs2_write_log_header(struct gfs2_sbd *sdp, struct gfs2_jdesc *jd,
u64 seq, u32 tail, u32 lblock, u32 flags,
int op_flags)
{
struct gfs2_log_header *lh;
u32 hash, crc;
struct page *page;
struct gfs2_statfs_change_host *l_sc = &sdp->sd_statfs_local;
struct timespec64 tv;
struct super_block *sb = sdp->sd_vfs;
u64 dblock;
if (gfs2_withdrawn(sdp))
return;
page = mempool_alloc(gfs2_page_pool, GFP_NOIO);
lh = page_address(page);
clear_page(lh);
lh->lh_header.mh_magic = cpu_to_be32(GFS2_MAGIC);
lh->lh_header.mh_type = cpu_to_be32(GFS2_METATYPE_LH);
lh->lh_header.__pad0 = cpu_to_be64(0);
lh->lh_header.mh_format = cpu_to_be32(GFS2_FORMAT_LH);
lh->lh_header.mh_jid = cpu_to_be32(sdp->sd_jdesc->jd_jid);
lh->lh_sequence = cpu_to_be64(seq);
lh->lh_flags = cpu_to_be32(flags);
lh->lh_tail = cpu_to_be32(tail);
lh->lh_blkno = cpu_to_be32(lblock);
hash = ~crc32(~0, lh, LH_V1_SIZE);
lh->lh_hash = cpu_to_be32(hash);
ktime_get_coarse_real_ts64(&tv);
lh->lh_nsec = cpu_to_be32(tv.tv_nsec);
lh->lh_sec = cpu_to_be64(tv.tv_sec);
if (!list_empty(&jd->extent_list))
dblock = gfs2_log_bmap(jd, lblock);
else {
int ret = gfs2_lblk_to_dblk(jd->jd_inode, lblock, &dblock);
if (gfs2_assert_withdraw(sdp, ret == 0))
return;
}
lh->lh_addr = cpu_to_be64(dblock);
lh->lh_jinode = cpu_to_be64(GFS2_I(jd->jd_inode)->i_no_addr);
/* We may only write local statfs, quota, etc., when writing to our
own journal. The values are left 0 when recovering a journal
different from our own. */
if (!(flags & GFS2_LOG_HEAD_RECOVERY)) {
lh->lh_statfs_addr =
cpu_to_be64(GFS2_I(sdp->sd_sc_inode)->i_no_addr);
lh->lh_quota_addr =
cpu_to_be64(GFS2_I(sdp->sd_qc_inode)->i_no_addr);
spin_lock(&sdp->sd_statfs_spin);
lh->lh_local_total = cpu_to_be64(l_sc->sc_total);
lh->lh_local_free = cpu_to_be64(l_sc->sc_free);
lh->lh_local_dinodes = cpu_to_be64(l_sc->sc_dinodes);
spin_unlock(&sdp->sd_statfs_spin);
}
BUILD_BUG_ON(offsetof(struct gfs2_log_header, lh_crc) != LH_V1_SIZE);
crc = crc32c(~0, (void *)lh + LH_V1_SIZE + 4,
sb->s_blocksize - LH_V1_SIZE - 4);
lh->lh_crc = cpu_to_be32(crc);
gfs2_log_write(sdp, jd, page, sb->s_blocksize, 0, dblock);
gfs2_log_submit_bio(&jd->jd_log_bio, REQ_OP_WRITE | op_flags);
}
/**
* log_write_header - Get and initialize a journal header buffer
* @sdp: The GFS2 superblock
* @flags: The log header flags, including log header origin
*
* Returns: the initialized log buffer descriptor
*/
static void log_write_header(struct gfs2_sbd *sdp, u32 flags)
{
int op_flags = REQ_PREFLUSH | REQ_FUA | REQ_META | REQ_SYNC;
enum gfs2_freeze_state state = atomic_read(&sdp->sd_freeze_state);
gfs2_assert_withdraw(sdp, (state != SFS_FROZEN));
if (test_bit(SDF_NOBARRIERS, &sdp->sd_flags)) {
gfs2_ordered_wait(sdp);
log_flush_wait(sdp);
op_flags = REQ_SYNC | REQ_META | REQ_PRIO;
}
sdp->sd_log_idle = (sdp->sd_log_flush_tail == sdp->sd_log_flush_head);
gfs2_write_log_header(sdp, sdp->sd_jdesc, sdp->sd_log_sequence++,
sdp->sd_log_flush_tail, sdp->sd_log_flush_head,
flags, op_flags);
gfs2_log_incr_head(sdp);
log_flush_wait(sdp);
log_pull_tail(sdp);
gfs2_log_update_head(sdp);
}
/**
* ail_drain - drain the ail lists after a withdraw
* @sdp: Pointer to GFS2 superblock
*/
static void ail_drain(struct gfs2_sbd *sdp)
{
struct gfs2_trans *tr;
spin_lock(&sdp->sd_ail_lock);
/*
* For transactions on the sd_ail1_list we need to drain both the
* ail1 and ail2 lists. That's because function gfs2_ail1_start_one
* (temporarily) moves items from its tr_ail1 list to tr_ail2 list
* before revokes are sent for that block. Items on the sd_ail2_list
* should have already gotten beyond that point, so no need.
*/
while (!list_empty(&sdp->sd_ail1_list)) {
tr = list_first_entry(&sdp->sd_ail1_list, struct gfs2_trans,
tr_list);
gfs2_ail_empty_tr(sdp, tr, &tr->tr_ail1_list);
gfs2_ail_empty_tr(sdp, tr, &tr->tr_ail2_list);
list_del(&tr->tr_list);
gfs2_trans_free(sdp, tr);
}
while (!list_empty(&sdp->sd_ail2_list)) {
tr = list_first_entry(&sdp->sd_ail2_list, struct gfs2_trans,
tr_list);
gfs2_ail_empty_tr(sdp, tr, &tr->tr_ail2_list);
list_del(&tr->tr_list);
gfs2_trans_free(sdp, tr);
}
spin_unlock(&sdp->sd_ail_lock);
}
/**
* empty_ail1_list - try to start IO and empty the ail1 list
* @sdp: Pointer to GFS2 superblock
*/
static void empty_ail1_list(struct gfs2_sbd *sdp)
{
unsigned long start = jiffies;
for (;;) {
if (time_after(jiffies, start + (HZ * 600))) {
fs_err(sdp, "Error: In %s for 10 minutes! t=%d\n",
__func__, current->journal_info ? 1 : 0);
dump_ail_list(sdp);
return;
}
gfs2_ail1_start(sdp);
gfs2_ail1_wait(sdp);
if (gfs2_ail1_empty(sdp, 0))
return;
}
}
/**
* trans_drain - drain the buf and databuf queue for a failed transaction
* @tr: the transaction to drain
*
* When this is called, we're taking an error exit for a log write that failed
* but since we bypassed the after_commit functions, we need to remove the
* items from the buf and databuf queue.
*/
static void trans_drain(struct gfs2_trans *tr)
{
struct gfs2_bufdata *bd;
struct list_head *head;
if (!tr)
return;
head = &tr->tr_buf;
while (!list_empty(head)) {
bd = list_first_entry(head, struct gfs2_bufdata, bd_list);
list_del_init(&bd->bd_list);
if (!list_empty(&bd->bd_ail_st_list))
gfs2_remove_from_ail(bd);
kmem_cache_free(gfs2_bufdata_cachep, bd);
}
head = &tr->tr_databuf;
while (!list_empty(head)) {
bd = list_first_entry(head, struct gfs2_bufdata, bd_list);
list_del_init(&bd->bd_list);
if (!list_empty(&bd->bd_ail_st_list))
gfs2_remove_from_ail(bd);
kmem_cache_free(gfs2_bufdata_cachep, bd);
}
}
/**
* gfs2_log_flush - flush incore transaction(s)
* @sdp: the filesystem
* @gl: The glock structure to flush. If NULL, flush the whole incore log
* @flags: The log header flags: GFS2_LOG_HEAD_FLUSH_* and debug flags
*
*/
void gfs2_log_flush(struct gfs2_sbd *sdp, struct gfs2_glock *gl, u32 flags)
{
struct gfs2_trans *tr = NULL;
unsigned int reserved_blocks = 0, used_blocks = 0;
enum gfs2_freeze_state state = atomic_read(&sdp->sd_freeze_state);
unsigned int first_log_head;
unsigned int reserved_revokes = 0;
down_write(&sdp->sd_log_flush_lock);
trace_gfs2_log_flush(sdp, 1, flags);
repeat:
/*
* Do this check while holding the log_flush_lock to prevent new
* buffers from being added to the ail via gfs2_pin()
*/
if (gfs2_withdrawn(sdp) || !test_bit(SDF_JOURNAL_LIVE, &sdp->sd_flags))
goto out;
/* Log might have been flushed while we waited for the flush lock */
if (gl && !test_bit(GLF_LFLUSH, &gl->gl_flags))
goto out;
first_log_head = sdp->sd_log_head;
sdp->sd_log_flush_head = first_log_head;
tr = sdp->sd_log_tr;
if (tr || sdp->sd_log_num_revoke) {
if (reserved_blocks)
gfs2_log_release(sdp, reserved_blocks);
reserved_blocks = sdp->sd_log_blks_reserved;
reserved_revokes = sdp->sd_log_num_revoke;
if (tr) {
sdp->sd_log_tr = NULL;
tr->tr_first = first_log_head;
if (unlikely (state == SFS_FROZEN)) {
if (gfs2_assert_withdraw_delayed(sdp,
!tr->tr_num_buf_new && !tr->tr_num_databuf_new))
goto out_withdraw;
}
}
} else if (!reserved_blocks) {
unsigned int taboo_blocks = GFS2_LOG_FLUSH_MIN_BLOCKS;
reserved_blocks = GFS2_LOG_FLUSH_MIN_BLOCKS;
if (current == sdp->sd_logd_process)
taboo_blocks = 0;
if (!__gfs2_log_try_reserve(sdp, reserved_blocks, taboo_blocks)) {
up_write(&sdp->sd_log_flush_lock);
__gfs2_log_reserve(sdp, reserved_blocks, taboo_blocks);
down_write(&sdp->sd_log_flush_lock);
goto repeat;
}
BUG_ON(sdp->sd_log_num_revoke);
}
if (flags & GFS2_LOG_HEAD_FLUSH_SHUTDOWN)
clear_bit(SDF_JOURNAL_LIVE, &sdp->sd_flags);
if (unlikely(state == SFS_FROZEN))
if (gfs2_assert_withdraw_delayed(sdp, !reserved_revokes))
goto out_withdraw;
gfs2_ordered_write(sdp);
if (gfs2_withdrawn(sdp))
goto out_withdraw;
lops_before_commit(sdp, tr);
if (gfs2_withdrawn(sdp))
goto out_withdraw;
gfs2_log_submit_bio(&sdp->sd_jdesc->jd_log_bio, REQ_OP_WRITE);
if (gfs2_withdrawn(sdp))
goto out_withdraw;
if (sdp->sd_log_head != sdp->sd_log_flush_head) {
log_write_header(sdp, flags);
} else if (sdp->sd_log_tail != sdp->sd_log_flush_tail && !sdp->sd_log_idle) {
log_write_header(sdp, flags);
}
if (gfs2_withdrawn(sdp))
goto out_withdraw;
lops_after_commit(sdp, tr);
gfs2_log_lock(sdp);
sdp->sd_log_blks_reserved = 0;
spin_lock(&sdp->sd_ail_lock);
if (tr && !list_empty(&tr->tr_ail1_list)) {
list_add(&tr->tr_list, &sdp->sd_ail1_list);
tr = NULL;
}
spin_unlock(&sdp->sd_ail_lock);
gfs2_log_unlock(sdp);
if (!(flags & GFS2_LOG_HEAD_FLUSH_NORMAL)) {
if (!sdp->sd_log_idle) {
empty_ail1_list(sdp);
if (gfs2_withdrawn(sdp))
goto out_withdraw;
log_write_header(sdp, flags);
}
if (flags & (GFS2_LOG_HEAD_FLUSH_SHUTDOWN |
GFS2_LOG_HEAD_FLUSH_FREEZE))
gfs2_log_shutdown(sdp);
if (flags & GFS2_LOG_HEAD_FLUSH_FREEZE)
atomic_set(&sdp->sd_freeze_state, SFS_FROZEN);
}
out_end:
used_blocks = log_distance(sdp, sdp->sd_log_flush_head, first_log_head);
reserved_revokes += atomic_read(&sdp->sd_log_revokes_available);
atomic_set(&sdp->sd_log_revokes_available, sdp->sd_ldptrs);
gfs2_assert_withdraw(sdp, reserved_revokes % sdp->sd_inptrs == sdp->sd_ldptrs);
if (reserved_revokes > sdp->sd_ldptrs)
reserved_blocks += (reserved_revokes - sdp->sd_ldptrs) / sdp->sd_inptrs;
out:
if (used_blocks != reserved_blocks) {
gfs2_assert_withdraw_delayed(sdp, used_blocks < reserved_blocks);
gfs2_log_release(sdp, reserved_blocks - used_blocks);
}
up_write(&sdp->sd_log_flush_lock);
gfs2_trans_free(sdp, tr);
if (gfs2_withdrawing(sdp))
gfs2_withdraw(sdp);
trace_gfs2_log_flush(sdp, 0, flags);
return;
out_withdraw:
trans_drain(tr);
/**
* If the tr_list is empty, we're withdrawing during a log
* flush that targets a transaction, but the transaction was
* never queued onto any of the ail lists. Here we add it to
* ail1 just so that ail_drain() will find and free it.
*/
spin_lock(&sdp->sd_ail_lock);
if (tr && list_empty(&tr->tr_list))
list_add(&tr->tr_list, &sdp->sd_ail1_list);
spin_unlock(&sdp->sd_ail_lock);
ail_drain(sdp); /* frees all transactions */
tr = NULL;
goto out_end;
}
/**
* gfs2_merge_trans - Merge a new transaction into a cached transaction
* @old: Original transaction to be expanded
* @new: New transaction to be merged
*/
static void gfs2_merge_trans(struct gfs2_sbd *sdp, struct gfs2_trans *new)
{
struct gfs2_trans *old = sdp->sd_log_tr;
WARN_ON_ONCE(!test_bit(TR_ATTACHED, &old->tr_flags));
old->tr_num_buf_new += new->tr_num_buf_new;
old->tr_num_databuf_new += new->tr_num_databuf_new;
old->tr_num_buf_rm += new->tr_num_buf_rm;
old->tr_num_databuf_rm += new->tr_num_databuf_rm;
old->tr_revokes += new->tr_revokes;
old->tr_num_revoke += new->tr_num_revoke;
list_splice_tail_init(&new->tr_databuf, &old->tr_databuf);
list_splice_tail_init(&new->tr_buf, &old->tr_buf);
spin_lock(&sdp->sd_ail_lock);
list_splice_tail_init(&new->tr_ail1_list, &old->tr_ail1_list);
list_splice_tail_init(&new->tr_ail2_list, &old->tr_ail2_list);
spin_unlock(&sdp->sd_ail_lock);
}
static void log_refund(struct gfs2_sbd *sdp, struct gfs2_trans *tr)
{
unsigned int reserved;
unsigned int unused;
unsigned int maxres;
gfs2_log_lock(sdp);
if (sdp->sd_log_tr) {
gfs2_merge_trans(sdp, tr);
} else if (tr->tr_num_buf_new || tr->tr_num_databuf_new) {
gfs2_assert_withdraw(sdp, !test_bit(TR_ONSTACK, &tr->tr_flags));
sdp->sd_log_tr = tr;
set_bit(TR_ATTACHED, &tr->tr_flags);
}
reserved = calc_reserved(sdp);
maxres = sdp->sd_log_blks_reserved + tr->tr_reserved;
gfs2_assert_withdraw(sdp, maxres >= reserved);
unused = maxres - reserved;
if (unused)
gfs2_log_release(sdp, unused);
sdp->sd_log_blks_reserved = reserved;
gfs2_log_unlock(sdp);
}
/**
* gfs2_log_commit - Commit a transaction to the log
* @sdp: the filesystem
* @tr: the transaction
*
* We wake up gfs2_logd if the number of pinned blocks exceed thresh1
* or the total number of used blocks (pinned blocks plus AIL blocks)
* is greater than thresh2.
*
* At mount time thresh1 is 2/5ths of journal size, thresh2 is 4/5ths of
* journal size.
*
* Returns: errno
*/
void gfs2_log_commit(struct gfs2_sbd *sdp, struct gfs2_trans *tr)
{
log_refund(sdp, tr);
if (atomic_read(&sdp->sd_log_pinned) > atomic_read(&sdp->sd_log_thresh1) ||
((sdp->sd_jdesc->jd_blocks - atomic_read(&sdp->sd_log_blks_free)) >
atomic_read(&sdp->sd_log_thresh2)))
wake_up(&sdp->sd_logd_waitq);
}
/**
* gfs2_log_shutdown - write a shutdown header into a journal
* @sdp: the filesystem
*
*/
static void gfs2_log_shutdown(struct gfs2_sbd *sdp)
{
gfs2_assert_withdraw(sdp, !sdp->sd_log_blks_reserved);
gfs2_assert_withdraw(sdp, !sdp->sd_log_num_revoke);
gfs2_assert_withdraw(sdp, list_empty(&sdp->sd_ail1_list));
log_write_header(sdp, GFS2_LOG_HEAD_UNMOUNT | GFS2_LFC_SHUTDOWN);
log_pull_tail(sdp);
gfs2_assert_warn(sdp, sdp->sd_log_head == sdp->sd_log_tail);
gfs2_assert_warn(sdp, list_empty(&sdp->sd_ail2_list));
}
static inline int gfs2_jrnl_flush_reqd(struct gfs2_sbd *sdp)
{
return (atomic_read(&sdp->sd_log_pinned) +
atomic_read(&sdp->sd_log_blks_needed) >=
atomic_read(&sdp->sd_log_thresh1));
}
static inline int gfs2_ail_flush_reqd(struct gfs2_sbd *sdp)
{
unsigned int used_blocks = sdp->sd_jdesc->jd_blocks - atomic_read(&sdp->sd_log_blks_free);
if (test_and_clear_bit(SDF_FORCE_AIL_FLUSH, &sdp->sd_flags))
return 1;
return used_blocks + atomic_read(&sdp->sd_log_blks_needed) >=
atomic_read(&sdp->sd_log_thresh2);
}
/**
* gfs2_logd - Update log tail as Active Items get flushed to in-place blocks
* @sdp: Pointer to GFS2 superblock
*
* Also, periodically check to make sure that we're using the most recent
* journal index.
*/
int gfs2_logd(void *data)
{
struct gfs2_sbd *sdp = data;
unsigned long t = 1;
DEFINE_WAIT(wait);
while (!kthread_should_stop()) {
if (gfs2_withdrawn(sdp)) {
msleep_interruptible(HZ);
continue;
}
/* Check for errors writing to the journal */
if (sdp->sd_log_error) {
gfs2_lm(sdp,
"GFS2: fsid=%s: error %d: "
"withdrawing the file system to "
"prevent further damage.\n",
sdp->sd_fsname, sdp->sd_log_error);
gfs2_withdraw(sdp);
continue;
}
if (gfs2_jrnl_flush_reqd(sdp) || t == 0) {
gfs2_ail1_empty(sdp, 0);
gfs2_log_flush(sdp, NULL, GFS2_LOG_HEAD_FLUSH_NORMAL |
GFS2_LFC_LOGD_JFLUSH_REQD);
}
if (gfs2_ail_flush_reqd(sdp)) {
gfs2_ail1_start(sdp);
gfs2_ail1_wait(sdp);
gfs2_ail1_empty(sdp, 0);
gfs2_log_flush(sdp, NULL, GFS2_LOG_HEAD_FLUSH_NORMAL |
GFS2_LFC_LOGD_AIL_FLUSH_REQD);
}
t = gfs2_tune_get(sdp, gt_logd_secs) * HZ;
try_to_freeze();
do {
prepare_to_wait(&sdp->sd_logd_waitq, &wait,
TASK_INTERRUPTIBLE);
if (!gfs2_ail_flush_reqd(sdp) &&
!gfs2_jrnl_flush_reqd(sdp) &&
!kthread_should_stop())
t = schedule_timeout(t);
} while(t && !gfs2_ail_flush_reqd(sdp) &&
!gfs2_jrnl_flush_reqd(sdp) &&
!kthread_should_stop());
finish_wait(&sdp->sd_logd_waitq, &wait);
}
return 0;
}
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