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authorOGAWA Hirofumi <hirofumi@mail.parknet.co.jp>2008-11-06 12:53:56 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2008-11-06 15:41:21 -0800
commitfa93ca18a8b0da4e26bd9491ad144cd14d22f8ec (patch)
tree2950aa2baa218493329873a61aa234c7fcc5d83e
parentdfc209c0064efef5590f608056a48b61a5cac09c (diff)
downloadlinux-2.6.38-lt-ux500-fa93ca18a8b0da4e26bd9491ad144cd14d22f8ec.tar.gz
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 <hirofumi@mail.parknet.co.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--fs/fat/inode.c9
1 files changed, 8 insertions, 1 deletions
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 = {