JFS: Take logsync lock before testing mp->lsn
Dave Kleikamp [Wed, 8 Mar 2006 16:59:15 +0000 (10:59 -0600)]
This fixes a race where lsn could be cleared before taking the lock

Signed-off-by: Dave Kleikamp <shaggy@austin.ibm.com>

fs/jfs/jfs_dmap.c
fs/jfs/jfs_imap.c

index 4fb3ed1..c161c98 100644 (file)
@@ -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. */
index 87dd86c..b62a048 100644 (file)
@@ -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);
 }