From: Wendy Cheng <wcheng@redhat.com>
Subject: [RHEL 5.1 PATCH] Fix i_cache stale entry
Date: Wed, 19 Sep 2007 12:20:34 -0400
Bugzilla: 253756
Message-Id: <46F14C52.50506@redhat.com>
Changelog: [GFS2] Fix i_cache stale entry


Two fixes: first one fixes i_cache flush problem. Upon glock lock 
transfer, if the file is a large sparse file, the gfs2_meta_cache_flush 
prematurely stops the flushing that leaves stale entries around. This 
has generated few nasty issues including data corruption. Second one 
corrects checking in gfs2_get_block_noalloc upon unmapped buffer.

-- Wendy


--- e47-brew/fs/gfs2/meta_io.c	2007-09-18 07:33:00.000000000 -0500
+++ e47/fs/gfs2/meta_io.c	2007-09-18 16:24:51.000000000 -0500
@@ -374,10 +374,10 @@ void gfs2_meta_cache_flush(struct gfs2_i
 
 	for (x = 0; x < GFS2_MAX_META_HEIGHT; x++) {
 		bh_slot = &ip->i_cache[x];
-		if (!*bh_slot)
-			break;
-		brelse(*bh_slot);
-		*bh_slot = NULL;
+		if (*bh_slot) {
+			brelse(*bh_slot);
+			*bh_slot = NULL;
+		}
 	}
 
 	spin_unlock(&ip->i_spin);
--- e47-brew/fs/gfs2/ops_address.c	2007-09-18 07:33:00.000000000 -0500
+++ e47/fs/gfs2/ops_address.c	2007-09-19 10:54:39.000000000 -0500
@@ -90,7 +90,7 @@ static int gfs2_get_block_noalloc(struct
 	error = gfs2_block_map(inode, lblock, 0, bh_result);
 	if (error)
 		return error;
-	if (bh_result->b_blocknr == 0)
+	if (!buffer_mapped(bh_result))
 		return -EIO;
 	return 0;
 }