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

fs/jfs/jfs_dmap.c

+2 −5
Original line number Diff line number Diff line
@@ -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. */

fs/jfs/jfs_imap.c

+2 −4
Original line number Diff line number Diff line
@@ -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);

}