From 5e76e584d0b4e24eed04871d807b3081e97bcfb2 Mon Sep 17 00:00:00 2001 From: Kazuya Mio Date: Mon, 7 Apr 2014 10:53:28 -0400 Subject: [PATCH] ext4: FIBMAP ioctl causes BUG_ON due to handle EXT_MAX_BLOCKS commit 4adb6ab3e0fa71363a5ef229544b2d17de6600d7 upstream. When we try to get 2^32-1 block of the file which has the extent (ee_block=2^32-2, ee_len=1) with FIBMAP ioctl, it causes BUG_ON in ext4_ext_put_gap_in_cache(). To avoid the problem, ext4_map_blocks() needs to check the file logical block number. ext4_ext_put_gap_in_cache() called via ext4_map_blocks() cannot handle 2^32-1 because the maximum file logical block number is 2^32-2. Note that ext4_ind_map_blocks() returns -EIO when the block number is invalid. So ext4_map_blocks() should also return the same errno. Signed-off-by: Kazuya Mio Signed-off-by: "Theodore Ts'o" [bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings --- fs/ext4/inode.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index dc9f0ecd8f4a4..55d4f461992cf 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -481,6 +481,11 @@ int ext4_map_blocks(handle_t *handle, struct inode *inode, ext_debug("ext4_map_blocks(): inode %lu, flag %d, max_blocks %u," "logical block %lu\n", inode->i_ino, flags, map->m_len, (unsigned long) map->m_lblk); + + /* We can handle the block number less than EXT_MAX_BLOCKS */ + if (unlikely(map->m_lblk >= EXT_MAX_BLOCKS)) + return -EIO; + /* * Try to see if we can get the block without requesting a new * file system block. -- 2.47.3