From: OGAWA Hirofumi Date: Thu, 6 Nov 2008 20:53:56 +0000 (-0800) Subject: fat: Fix _fat_bmap() race X-Git-Tag: v2.6.28-rc4~38 X-Git-Url: http://pilppa.com/gitweb/?a=commitdiff_plain;h=fa93ca18a8b0da4e26bd9491ad144cd14d22f8ec;p=linux-2.6-omap-h63xx.git fat: Fix _fat_bmap() race fat_get_cluster() assumes the requested blocknr isn't truncated during read. _fat_bmap() doesn't follow this rule. This protects it by ->i_mutex. Signed-off-by: OGAWA Hirofumi Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/fs/fat/inode.c b/fs/fat/inode.c index 0da04e6d1e3..be88208b83a 100644 --- a/fs/fat/inode.c +++ b/fs/fat/inode.c @@ -199,7 +199,14 @@ static ssize_t fat_direct_IO(int rw, struct kiocb *iocb, static sector_t _fat_bmap(struct address_space *mapping, sector_t block) { - return generic_block_bmap(mapping, block, fat_get_block); + sector_t blocknr; + + /* fat_get_cluster() assumes the requested blocknr isn't truncated. */ + mutex_lock(&mapping->host->i_mutex); + blocknr = generic_block_bmap(mapping, block, fat_get_block); + mutex_unlock(&mapping->host->i_mutex); + + return blocknr; } static const struct address_space_operations fat_aops = {