[PATCH] __bread oops fix
If a filesystem passes an idiotic blocksize into bread(), __getblk_slow() will
warn and will return NULL. We have a report (from Hubert Tonneau
<hubert.tonneau@fullpliant.org>) of isofs_fill_super() doing this (passing in
a silly block size) against an unplugged CDROM drive.
But a couple of __getblk_slow() callers forgot to check for the NULL bh, hence
oops.
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/fs/buffer.c b/fs/buffer.c
index 75cac9a..35fa349 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -1478,8 +1478,10 @@
void __breadahead(struct block_device *bdev, sector_t block, int size)
{
struct buffer_head *bh = __getblk(bdev, block, size);
- ll_rw_block(READA, 1, &bh);
- brelse(bh);
+ if (likely(bh)) {
+ ll_rw_block(READA, 1, &bh);
+ brelse(bh);
+ }
}
EXPORT_SYMBOL(__breadahead);
@@ -1497,7 +1499,7 @@
{
struct buffer_head *bh = __getblk(bdev, block, size);
- if (!buffer_uptodate(bh))
+ if (likely(bh) && !buffer_uptodate(bh))
bh = __bread_slow(bh);
return bh;
}