vfs: check bh->b_blocknr only if BH_Mapped is set
Check bh->b_blocknr only if BH_Mapped is set.
akpm: I doubt if b_blocknr is ever uninitialised here, but it could
conceivably cause a problem if we're doing a lookup for block zero.
Signed-off-by: Nikanth Karthikesan <knikanth@suse.de>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/buffer.c b/fs/buffer.c
index f5f8b15..2963858 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -199,13 +199,13 @@
head = page_buffers(page);
bh = head;
do {
- if (bh->b_blocknr == block) {
+ if (!buffer_mapped(bh))
+ all_mapped = 0;
+ else if (bh->b_blocknr == block) {
ret = bh;
get_bh(bh);
goto out_unlock;
}
- if (!buffer_mapped(bh))
- all_mapped = 0;
bh = bh->b_this_page;
} while (bh != head);