From: Jan Kara <jack@xxxxxxx> This patch has been added to the 3.12 stable tree. If you have any objections, please let us know. =============== commit cd648b8a8fd5071d232242d5ee7ee3c0815776af upstream. 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@xxxxxxxxxxxxxxx> Signed-off-by: Jan Kara <jack@xxxxxxx> Signed-off-by: Theodore Ts'o <tytso@xxxxxxx> Signed-off-by: Jiri Slaby <jslaby@xxxxxxx> --- fs/ext4/mballoc.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c index 2b4ed2bf9569..16a763af556c 100644 --- a/fs/ext4/mballoc.c +++ b/fs/ext4/mballoc.c @@ -3084,6 +3084,13 @@ 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 */ -- 2.12.0