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ext4: FIBMAP ioctl causes BUG_ON due to handle EXT_MAX_BLOCKS 

commit 4adb6ab3e0 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 <k-mio@sx.jp.nec.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Kazuya Mio 2014-04-07 10:53:28 -04:00 committed by Greg Kroah-Hartman
parent b4140e2b76
commit 549b3cf1c4
1 changed files with 4 additions and 0 deletions
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4
fs/ext4/inode.c
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@ -515,6 +515,10 @@ int ext4_map_blocks(handle_t *handle, struct inode *inode,
"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;
/* Lookup extent status tree firstly */
if (ext4_es_lookup_extent(inode, map->m_lblk, &es)) {
ext4_es_lru_add(inode);