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alistair23-linux/fs/gfs2/log.c
Benjamin Marzinski 5dc39fe621 [GFS2] Fix journal off-by-one error 
log_refund() incorrectly assumed that if a transaction had been touched, it
always committed buffers to the incore log. Thus, when you got around to
flushing the log, you would need one more block than you committed, to account
for the header. So it automatically set reserved to 1, which had the effect of
making sdp->sd_log_blks_reserved one greater when you got to gfs2_log_flush().
However, if you don't actually commit anything to the incore log between
flushes, you don't need the header, because you aren't writing anything out.
With this patch, log_refund() only increments reservered to account for the
header if something has been committed since the last flush.

Signed-off-by: Benjamin E. Marzinski <bmarzins@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2006-08-25 09:57:41 -04:00

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/*
* Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
* Copyright (C) 2004-2006 Red Hat, Inc. All rights reserved.
*
* This copyrighted material is made available to anyone wishing to use,
* modify, copy, or redistribute it subject to the terms and conditions
* of the GNU General Public License v.2.
*/
#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 "gfs2.h"
#include "lm_interface.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"
#define PULL 1
/**
* gfs2_struct2blk - compute stuff
* @sdp: the filesystem
* @nstruct: the number of structures
* @ssize: the size of the 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 ssize)
{
unsigned int blks;
unsigned int first, second;
blks = 1;
first = (sdp->sd_sb.sb_bsize - sizeof(struct gfs2_log_descriptor)) /
ssize;
if (nstruct > first) {
second = (sdp->sd_sb.sb_bsize -
sizeof(struct gfs2_meta_header)) / ssize;
blks += DIV_ROUND_UP(nstruct - first, second);
}
return blks;
}
void gfs2_ail1_start(struct gfs2_sbd *sdp, int flags)
{
struct list_head *head = &sdp->sd_ail1_list;
uint64_t sync_gen;
struct list_head *first, *tmp;
struct gfs2_ail *first_ai, *ai;
gfs2_log_lock(sdp);
if (list_empty(head)) {
gfs2_log_unlock(sdp);
return;
}
sync_gen = sdp->sd_ail_sync_gen++;
first = head->prev;
first_ai = list_entry(first, struct gfs2_ail, ai_list);
first_ai->ai_sync_gen = sync_gen;
gfs2_ail1_start_one(sdp, first_ai);
if (flags & DIO_ALL)
first = NULL;
for (;;) {
if (first && (head->prev != first ||
gfs2_ail1_empty_one(sdp, first_ai, 0)))
break;
for (tmp = head->prev; tmp != head; tmp = tmp->prev) {
ai = list_entry(tmp, struct gfs2_ail, ai_list);
if (ai->ai_sync_gen >= sync_gen)
continue;
ai->ai_sync_gen = sync_gen;
gfs2_ail1_start_one(sdp, ai);
break;
}
if (tmp == head)
break;
}
gfs2_log_unlock(sdp);
}
int gfs2_ail1_empty(struct gfs2_sbd *sdp, int flags)
{
struct gfs2_ail *ai, *s;
int ret;
gfs2_log_lock(sdp);
list_for_each_entry_safe_reverse(ai, s, &sdp->sd_ail1_list, ai_list) {
if (gfs2_ail1_empty_one(sdp, ai, flags))
list_move(&ai->ai_list, &sdp->sd_ail2_list);
else if (!(flags & DIO_ALL))
break;
}
ret = list_empty(&sdp->sd_ail1_list);
gfs2_log_unlock(sdp);
return ret;
}
static void ail2_empty(struct gfs2_sbd *sdp, unsigned int new_tail)
{
struct gfs2_ail *ai, *safe;
unsigned int old_tail = sdp->sd_log_tail;
int wrap = (new_tail < old_tail);
int a, b, rm;
gfs2_log_lock(sdp);
list_for_each_entry_safe(ai, safe, &sdp->sd_ail2_list, ai_list) {
a = (old_tail <= ai->ai_first);
b = (ai->ai_first < new_tail);
rm = (wrap) ? (a || b) : (a && b);
if (!rm)
continue;
gfs2_ail2_empty_one(sdp, ai);
list_del(&ai->ai_list);
gfs2_assert_warn(sdp, list_empty(&ai->ai_ail1_list));
gfs2_assert_warn(sdp, list_empty(&ai->ai_ail2_list));
kfree(ai);
}
gfs2_log_unlock(sdp);
}
/**
* gfs2_log_reserve - Make a log reservation
* @sdp: The GFS2 superblock
* @blks: The number of blocks to reserve
*
* Returns: errno
*/
int gfs2_log_reserve(struct gfs2_sbd *sdp, unsigned int blks)
{
unsigned int try = 0;
if (gfs2_assert_warn(sdp, blks) ||
gfs2_assert_warn(sdp, blks <= sdp->sd_jdesc->jd_blocks))
return -EINVAL;
mutex_lock(&sdp->sd_log_reserve_mutex);
gfs2_log_lock(sdp);
while(sdp->sd_log_blks_free <= blks) {
gfs2_log_unlock(sdp);
gfs2_ail1_empty(sdp, 0);
gfs2_log_flush(sdp, NULL);
if (try++)
gfs2_ail1_start(sdp, 0);
gfs2_log_lock(sdp);
}
sdp->sd_log_blks_free -= blks;
/* printk(KERN_INFO "reserved %u blocks (%u left)\n", blks, sdp->sd_log_blks_free); */
gfs2_log_unlock(sdp);
mutex_unlock(&sdp->sd_log_reserve_mutex);
down_read(&sdp->sd_log_flush_lock);
return 0;
}
/**
* 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)
{
gfs2_log_lock(sdp);
sdp->sd_log_blks_free += blks;
/* printk(KERN_INFO "released %u blocks (%u left)\n", blks, sdp->sd_log_blks_free); */
gfs2_assert_withdraw(sdp,
sdp->sd_log_blks_free <= sdp->sd_jdesc->jd_blocks);
gfs2_log_unlock(sdp);
up_read(&sdp->sd_log_flush_lock);
}
static uint64_t log_bmap(struct gfs2_sbd *sdp, unsigned int lbn)
{
int new = 0;
uint64_t dbn;
int error;
int bdy;
error = gfs2_block_map(sdp->sd_jdesc->jd_inode, lbn, &new, &dbn, &bdy);
if (!(!error && dbn)) {
printk(KERN_INFO "error=%d, dbn=%llu lbn=%u", error, (unsigned long long)dbn, lbn);
}
gfs2_assert_withdraw(sdp, !error && dbn);
return dbn;
}
/**
* 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;
}
static unsigned int current_tail(struct gfs2_sbd *sdp)
{
struct gfs2_ail *ai;
unsigned int tail;
gfs2_log_lock(sdp);
if (list_empty(&sdp->sd_ail1_list))
tail = sdp->sd_log_head;
else {
ai = list_entry(sdp->sd_ail1_list.prev, struct gfs2_ail,
ai_list);
tail = ai->ai_first;
}
gfs2_log_unlock(sdp);
return tail;
}
static inline void log_incr_head(struct gfs2_sbd *sdp)
{
if (sdp->sd_log_flush_head == sdp->sd_log_tail)
gfs2_assert_withdraw(sdp,
sdp->sd_log_flush_head == sdp->sd_log_head);
if (++sdp->sd_log_flush_head == sdp->sd_jdesc->jd_blocks) {
sdp->sd_log_flush_head = 0;
sdp->sd_log_flush_wrapped = 1;
}
}
/**
* gfs2_log_get_buf - Get and initialize a buffer to use for log control data
* @sdp: The GFS2 superblock
*
* Returns: the buffer_head
*/
struct buffer_head *gfs2_log_get_buf(struct gfs2_sbd *sdp)
{
uint64_t blkno = log_bmap(sdp, sdp->sd_log_flush_head);
struct gfs2_log_buf *lb;
struct buffer_head *bh;
lb = kzalloc(sizeof(struct gfs2_log_buf), GFP_NOFS | __GFP_NOFAIL);
list_add(&lb->lb_list, &sdp->sd_log_flush_list);
bh = lb->lb_bh = sb_getblk(sdp->sd_vfs, blkno);
lock_buffer(bh);
memset(bh->b_data, 0, bh->b_size);
set_buffer_uptodate(bh);
clear_buffer_dirty(bh);
unlock_buffer(bh);
log_incr_head(sdp);
return bh;
}
/**
* gfs2_log_fake_buf - Build a fake buffer head to write metadata buffer to log
* @sdp: the filesystem
* @data: the data the buffer_head should point to
*
* Returns: the log buffer descriptor
*/
struct buffer_head *gfs2_log_fake_buf(struct gfs2_sbd *sdp,
struct buffer_head *real)
{
uint64_t blkno = log_bmap(sdp, sdp->sd_log_flush_head);
struct gfs2_log_buf *lb;
struct buffer_head *bh;
lb = kzalloc(sizeof(struct gfs2_log_buf), GFP_NOFS | __GFP_NOFAIL);
list_add(&lb->lb_list, &sdp->sd_log_flush_list);
lb->lb_real = real;
bh = lb->lb_bh = alloc_buffer_head(GFP_NOFS | __GFP_NOFAIL);
atomic_set(&bh->b_count, 1);
bh->b_state = (1 << BH_Mapped) | (1 << BH_Uptodate);
set_bh_page(bh, real->b_page, bh_offset(real));
bh->b_blocknr = blkno;
bh->b_size = sdp->sd_sb.sb_bsize;
bh->b_bdev = sdp->sd_vfs->s_bdev;
log_incr_head(sdp);
return bh;
}
static void log_pull_tail(struct gfs2_sbd *sdp, unsigned int new_tail, int pull)
{
unsigned int dist = log_distance(sdp, new_tail, sdp->sd_log_tail);
ail2_empty(sdp, new_tail);
gfs2_log_lock(sdp);
sdp->sd_log_blks_free += dist - ((pull) ? 1 : 0);
/* printk(KERN_INFO "pull tail refunding %u blocks (%u left) pull=%d\n", dist - ((pull) ? 1 : 0), sdp->sd_log_blks_free, pull); */
gfs2_assert_withdraw(sdp,
sdp->sd_log_blks_free <= sdp->sd_jdesc->jd_blocks);
gfs2_log_unlock(sdp);
sdp->sd_log_tail = new_tail;
}
/**
* log_write_header - Get and initialize a journal header buffer
* @sdp: The GFS2 superblock
*
* Returns: the initialized log buffer descriptor
*/
static void log_write_header(struct gfs2_sbd *sdp, uint32_t flags, int pull)
{
uint64_t blkno = log_bmap(sdp, sdp->sd_log_flush_head);
struct buffer_head *bh;
struct gfs2_log_header *lh;
unsigned int tail;
uint32_t hash;
/* printk(KERN_INFO "log write header start (flags=%08x, pull=%d)\n", flags, pull); */
bh = sb_getblk(sdp->sd_vfs, blkno);
lock_buffer(bh);
memset(bh->b_data, 0, bh->b_size);
set_buffer_uptodate(bh);
clear_buffer_dirty(bh);
unlock_buffer(bh);
gfs2_ail1_empty(sdp, 0);
tail = current_tail(sdp);
lh = (struct gfs2_log_header *)bh->b_data;
memset(lh, 0, sizeof(struct gfs2_log_header));
lh->lh_header.mh_magic = cpu_to_be32(GFS2_MAGIC);
lh->lh_header.mh_type = cpu_to_be32(GFS2_METATYPE_LH);
lh->lh_header.mh_format = cpu_to_be32(GFS2_FORMAT_LH);
lh->lh_sequence = cpu_to_be64(sdp->sd_log_sequence++);
lh->lh_flags = cpu_to_be32(flags);
lh->lh_tail = cpu_to_be32(tail);
lh->lh_blkno = cpu_to_be32(sdp->sd_log_flush_head);
hash = gfs2_disk_hash(bh->b_data, sizeof(struct gfs2_log_header));
lh->lh_hash = cpu_to_be32(hash);
set_buffer_dirty(bh);
if (sync_dirty_buffer(bh))
gfs2_io_error_bh(sdp, bh);
brelse(bh);
if (sdp->sd_log_tail != tail)
log_pull_tail(sdp, tail, pull);
else
gfs2_assert_withdraw(sdp, !pull);
sdp->sd_log_idle = (tail == sdp->sd_log_flush_head);
log_incr_head(sdp);
/* printk(KERN_INFO "log write header out\n"); */
}
static void log_flush_commit(struct gfs2_sbd *sdp)
{
struct list_head *head = &sdp->sd_log_flush_list;
struct gfs2_log_buf *lb;
struct buffer_head *bh;
#if 0
unsigned int d;
d = log_distance(sdp, sdp->sd_log_flush_head, sdp->sd_log_head);
gfs2_assert_withdraw(sdp, d + 1 == sdp->sd_log_blks_reserved);
#endif
while (!list_empty(head)) {
lb = list_entry(head->next, struct gfs2_log_buf, lb_list);
list_del(&lb->lb_list);
bh = lb->lb_bh;
wait_on_buffer(bh);
if (!buffer_uptodate(bh))
gfs2_io_error_bh(sdp, bh);
if (lb->lb_real) {
while (atomic_read(&bh->b_count) != 1) /* Grrrr... */
schedule();
free_buffer_head(bh);
} else
brelse(bh);
kfree(lb);
}
log_write_header(sdp, 0, 0);
}
/**
* gfs2_log_flush - flush incore transaction(s)
* @sdp: the filesystem
* @gl: The glock structure to flush. If NULL, flush the whole incore log
*
*/
void gfs2_log_flush(struct gfs2_sbd *sdp, struct gfs2_glock *gl)
{
struct gfs2_ail *ai;
down_write(&sdp->sd_log_flush_lock);
if (gl) {
gfs2_log_lock(sdp);
if (list_empty(&gl->gl_le.le_list)) {
gfs2_log_unlock(sdp);
up_write(&sdp->sd_log_flush_lock);
return;
}
gfs2_log_unlock(sdp);
}
ai = kzalloc(sizeof(struct gfs2_ail), GFP_NOFS | __GFP_NOFAIL);
INIT_LIST_HEAD(&ai->ai_ail1_list);
INIT_LIST_HEAD(&ai->ai_ail2_list);
gfs2_assert_withdraw(sdp,
sdp->sd_log_num_buf == sdp->sd_log_commited_buf);
gfs2_assert_withdraw(sdp,
sdp->sd_log_num_revoke == sdp->sd_log_commited_revoke);
sdp->sd_log_flush_head = sdp->sd_log_head;
sdp->sd_log_flush_wrapped = 0;
ai->ai_first = sdp->sd_log_flush_head;
lops_before_commit(sdp);
if (!list_empty(&sdp->sd_log_flush_list))
log_flush_commit(sdp);
else if (sdp->sd_log_tail != current_tail(sdp) && !sdp->sd_log_idle)
log_write_header(sdp, 0, PULL);
lops_after_commit(sdp, ai);
sdp->sd_log_head = sdp->sd_log_flush_head;
/* printk(KERN_INFO "sd_log_num_hdrs %u\n", sdp->sd_log_num_hdrs); */
sdp->sd_log_blks_free -= sdp->sd_log_num_hdrs;
sdp->sd_log_blks_reserved =
sdp->sd_log_commited_buf =
sdp->sd_log_num_hdrs =
sdp->sd_log_commited_revoke = 0;
gfs2_log_lock(sdp);
if (!list_empty(&ai->ai_ail1_list)) {
list_add(&ai->ai_list, &sdp->sd_ail1_list);
ai = NULL;
}
gfs2_log_unlock(sdp);
sdp->sd_vfs->s_dirt = 0;
up_write(&sdp->sd_log_flush_lock);
kfree(ai);
}
static void log_refund(struct gfs2_sbd *sdp, struct gfs2_trans *tr)
{
unsigned int reserved = 0;
unsigned int old;
gfs2_log_lock(sdp);
sdp->sd_log_commited_buf += tr->tr_num_buf_new - tr->tr_num_buf_rm;
gfs2_assert_withdraw(sdp, ((int)sdp->sd_log_commited_buf) >= 0);
sdp->sd_log_commited_revoke += tr->tr_num_revoke - tr->tr_num_revoke_rm;
gfs2_assert_withdraw(sdp, ((int)sdp->sd_log_commited_revoke) >= 0);
if (sdp->sd_log_commited_buf)
reserved += sdp->sd_log_commited_buf;
if (sdp->sd_log_commited_revoke)
reserved += gfs2_struct2blk(sdp, sdp->sd_log_commited_revoke,
sizeof(uint64_t));
if (reserved)
reserved++;
old = sdp->sd_log_blks_free;
sdp->sd_log_blks_free += tr->tr_reserved -
(reserved - sdp->sd_log_blks_reserved);
gfs2_assert_withdraw(sdp, sdp->sd_log_blks_free >= old);
gfs2_assert_withdraw(sdp,
sdp->sd_log_blks_free <= sdp->sd_jdesc->jd_blocks +
sdp->sd_log_num_hdrs);
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
*
* Returns: errno
*/
void gfs2_log_commit(struct gfs2_sbd *sdp, struct gfs2_trans *tr)
{
log_refund(sdp, tr);
lops_incore_commit(sdp, tr);
sdp->sd_vfs->s_dirt = 1;
up_read(&sdp->sd_log_flush_lock);
gfs2_log_lock(sdp);
if (sdp->sd_log_num_buf > gfs2_tune_get(sdp, gt_incore_log_blocks)) {
gfs2_log_unlock(sdp);
gfs2_log_flush(sdp, NULL);
} else
gfs2_log_unlock(sdp);
}
/**
* gfs2_log_shutdown - write a shutdown header into a journal
* @sdp: the filesystem
*
*/
void gfs2_log_shutdown(struct gfs2_sbd *sdp)
{
down_write(&sdp->sd_log_flush_lock);
gfs2_assert_withdraw(sdp, !sdp->sd_log_blks_reserved);
gfs2_assert_withdraw(sdp, !sdp->sd_log_num_gl);
gfs2_assert_withdraw(sdp, !sdp->sd_log_num_buf);
gfs2_assert_withdraw(sdp, !sdp->sd_log_num_jdata);
gfs2_assert_withdraw(sdp, !sdp->sd_log_num_revoke);
gfs2_assert_withdraw(sdp, !sdp->sd_log_num_rg);
gfs2_assert_withdraw(sdp, !sdp->sd_log_num_databuf);
gfs2_assert_withdraw(sdp, !sdp->sd_log_num_hdrs);
gfs2_assert_withdraw(sdp, list_empty(&sdp->sd_ail1_list));
sdp->sd_log_flush_head = sdp->sd_log_head;
sdp->sd_log_flush_wrapped = 0;
log_write_header(sdp, GFS2_LOG_HEAD_UNMOUNT, 0);
/* printk(KERN_INFO "sd_log_blks_free %u, sd_jdesc->jd_blocks %u\n", sdp->sd_log_blks_free, sdp->sd_jdesc->jd_blocks); */
gfs2_assert_warn(sdp, sdp->sd_log_blks_free == sdp->sd_jdesc->jd_blocks);
gfs2_assert_warn(sdp, sdp->sd_log_head == sdp->sd_log_tail);
gfs2_assert_warn(sdp, list_empty(&sdp->sd_ail2_list));
sdp->sd_log_head = sdp->sd_log_flush_head;
sdp->sd_log_tail = sdp->sd_log_head;
up_write(&sdp->sd_log_flush_lock);
}
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