3.2.59-rc1 review patch. If anyone has any objections, please let me know.
------------------
From: Kazuya Mio <k-mio@xxxxxxxxxxxxx>
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 <k-mio@xxxxxxxxxxxxx>
Signed-off-by: "Theodore Ts'o" <tytso@xxxxxxx>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -481,6 +481,11 @@ int ext4_map_blocks(handle_t *handle, st
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.
--
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