[PATCH] fix race in jfs_commit_inode (1 of 1)

# This is a BitKeeper generated diff -Nru style patch.
#
# ChangeSet
#   2004/11/17 12:51:43-06:00 [email protected] 
#   JFS: fix race in jfs_commit_inode
#   
#   There was a race that resulted in old, deleted inodes being written
#   to disk after the inode number had been reused.  jfs_commit_inode
#   needs to verify that the inode is still linked and dirty before
#   committing it.
#   
#   Signed-off-by: Dave Kleikamp <[email protected]>
# 
diff -Nru a/fs/jfs/inode.c b/fs/jfs/inode.c
--- a/fs/jfs/inode.c	2004-11-22 08:26:51 -06:00
+++ b/fs/jfs/inode.c	2004-11-22 08:26:51 -06:00
@@ -81,8 +81,7 @@
 	 * Don't commit if inode has been committed since last being
 	 * marked dirty, or if it has been deleted.
 	 */
-	if (test_cflag(COMMIT_Nolink, inode) ||
-	    !test_cflag(COMMIT_Dirty, inode))
+	if (inode->i_nlink == 0 || !test_cflag(COMMIT_Dirty, inode))
 		return 0;
 
 	if (isReadOnly(inode)) {
@@ -100,7 +99,13 @@
 
 	tid = txBegin(inode->i_sb, COMMIT_INODE);
 	down(&JFS_IP(inode)->commit_sem);
-	rc = txCommit(tid, 1, &inode, wait ? COMMIT_SYNC : 0);
+
+	/*
+	 * Retest inode state after taking commit_sem
+	 */
+	if (inode->i_nlink && test_cflag(COMMIT_Dirty, inode))
+		rc = txCommit(tid, 1, &inode, wait ? COMMIT_SYNC : 0);
+
 	txEnd(tid);
 	up(&JFS_IP(inode)->commit_sem);
 	return rc;