[GFS2] Data corruption fix

* GFS2 has been using i_cache array to store its indirect meta blocks. Its flush routine doesn't correctly clean up all the entries. The problem would show while multiple nodes do simultaneous writes to the same file. Upon glock exclusive lock transfer, if the file is a sparse file with large file size where the indirect meta blocks span multiple array entries with "zero" entries in between. The flush routine prematurely stops the flushing that leaves old (stale) entries around. This leads to several nasty issues, including data corruption. * Fix gfs2_get_block_noalloc checking to correctly return EIO upon unmapped buffer. Signed-off-by: Wendy Cheng <[email protected]> Signed-off-by: Steven Whitehouse <[email protected]>
RyanHsu · Oct 10, 2007 · de986e8 · de986e8
1 parent 16615be
commit de986e8
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Showing 2 changed files with 5 additions and 5 deletions.
diff --git a/fs/gfs2/meta_io.c b/fs/gfs2/meta_io.c
@@ -374,10 +374,10 @@ void gfs2_meta_cache_flush(struct gfs2_inode *ip)
 
 	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);

diff --git a/fs/gfs2/ops_address.c b/fs/gfs2/ops_address.c
@@ -90,7 +90,7 @@ static int gfs2_get_block_noalloc(struct inode *inode, sector_t lblock,
 	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;
 }