From a3e713b5fdd0e54c2e3c8909ccde2a98839e3a52 Mon Sep 17 00:00:00 2001 From: Andrew Morton Date: Sun, 30 Oct 2005 15:03:15 -0800 Subject: [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 ) 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 Signed-off-by: Linus Torvalds --- fs/buffer.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/fs/buffer.c b/fs/buffer.c index 75cac9ada02..35fa34977e8 100644 --- a/fs/buffer.c +++ b/fs/buffer.c @@ -1478,8 +1478,10 @@ EXPORT_SYMBOL(__getblk); 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 @@ __bread(struct block_device *bdev, sector_t block, int size) { struct buffer_head *bh = __getblk(bdev, block, size); - if (!buffer_uptodate(bh)) + if (likely(bh) && !buffer_uptodate(bh)) bh = __bread_slow(bh); return bh; } -- cgit v1.2.3