Commit a488edc9 authored by Dave Kleikamp's avatar Dave Kleikamp Committed by Linus Torvalds

[PATCH] JFS: Take logsync lock before testing mp->lsn

This fixes a race where lsn could be cleared before taking the lock
Signed-off-by: default avatarDave Kleikamp <shaggy@austin.ibm.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 0f511ea7
......@@ -532,10 +532,10 @@ dbUpdatePMap(struct inode *ipbmap,
lastlblkno = lblkno;
LOGSYNC_LOCK(log, flags);
if (mp->lsn != 0) {
/* inherit older/smaller lsn */
logdiff(diffp, mp->lsn, log);
LOGSYNC_LOCK(log, flags);
if (difft < diffp) {
mp->lsn = lsn;
......@@ -548,20 +548,17 @@ dbUpdatePMap(struct inode *ipbmap,
logdiff(diffp, mp->clsn, log);
if (difft > diffp)
mp->clsn = tblk->clsn;
LOGSYNC_UNLOCK(log, flags);
} else {
mp->log = log;
mp->lsn = lsn;
/* insert bp after tblock in logsync list */
LOGSYNC_LOCK(log, flags);
log->count++;
list_add(&mp->synclist, &tblk->synclist);
mp->clsn = tblk->clsn;
LOGSYNC_UNLOCK(log, flags);
}
LOGSYNC_UNLOCK(log, flags);
}
/* write the last buffer. */
......
......@@ -2844,11 +2844,11 @@ diUpdatePMap(struct inode *ipimap,
*/
lsn = tblk->lsn;
log = JFS_SBI(tblk->sb)->log;
LOGSYNC_LOCK(log, flags);
if (mp->lsn != 0) {
/* inherit older/smaller lsn */
logdiff(difft, lsn, log);
logdiff(diffp, mp->lsn, log);
LOGSYNC_LOCK(log, flags);
if (difft < diffp) {
mp->lsn = lsn;
/* move mp after tblock in logsync list */
......@@ -2860,17 +2860,15 @@ diUpdatePMap(struct inode *ipimap,
logdiff(diffp, mp->clsn, log);
if (difft > diffp)
mp->clsn = tblk->clsn;
LOGSYNC_UNLOCK(log, flags);
} else {
mp->log = log;
mp->lsn = lsn;
/* insert mp after tblock in logsync list */
LOGSYNC_LOCK(log, flags);
log->count++;
list_add(&mp->synclist, &tblk->synclist);
mp->clsn = tblk->clsn;
LOGSYNC_UNLOCK(log, flags);
}
LOGSYNC_UNLOCK(log, flags);
write_metapage(mp);
return (0);
}
......
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