ext4: trim allocation requests to group size

If filesystem groups are artifically small (using parameter -g to
mkfs.ext4), ext4_mb_normalize_request() can result in a request that is
larger than a block group. Trim the request size to not confuse
allocation code.

Reported-by: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@vger.kernel.org
This commit is contained in:
Jan Kara 2017-01-27 14:34:30 -05:00 committed by Theodore Ts'o
parent 43c73221b3
commit cd648b8a8f
1 changed files with 7 additions and 0 deletions

View File

@ -3133,6 +3133,13 @@ ext4_mb_normalize_request(struct ext4_allocation_context *ac,
if (ar->pright && start + size - 1 >= ar->lright)
size -= start + size - ar->lright;
/*
* Trim allocation request for filesystems with artificially small
* groups.
*/
if (size > EXT4_BLOCKS_PER_GROUP(ac->ac_sb))
size = EXT4_BLOCKS_PER_GROUP(ac->ac_sb);
end = start + size;
/* check we don't cross already preallocated blocks */