On Mon, Mar 13, 2017 at 03:52:10PM +0800, Qu Wenruo wrote: > [BUG] > The easist way to reproduce the bug is: > ------ > # mkfs.btrfs -f $dev -n 16K > # mount $dev $mnt -o inode_cache > # btrfs quota enable $mnt > # btrfs quota rescan -w $mnt > # btrfs qgroup show $mnt > qgroupid rfer excl > -------- ---- ---- > 0/5 32.00KiB 32.00KiB > ^^ Twice the correct value > ------ > > And fstests/btrfs qgroup test group can easily detect them with > inode_cache mount option. > Although some of them are false alerts since old test cases are using > fixed golden output. > While new test cases will use "btrfs check" to detect qgroup mismatch. > > [CAUSE] > Inode_cache mount option will make commit_fs_roots() to call > btrfs_save_ino_cache() to update fs/subvol trees, and generate new > delayed refs. > > However we call btrfs_qgroup_prepare_account_extents() too early, before > commit_fs_roots(). > This makes the "old_roots" for newly generated extents are always NULL. > For freeing extent case, this makes both new_roots and old_roots to be > empty, while correct old_roots should not be empty. > This causing qgroup numbers not decreased correctly. > > [FIX] > Modify the timing of calling btrfs_qgroup_prepare_account_extents() to > just before btrfs_qgroup_account_extents(), and add needed delayed_refs > handler. > So qgroup can handle inode_map mount options correctly. > > Signed-off-by: Qu Wenruo <quwen...@cn.fujitsu.com>
Patch added to 4.12 queue. -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
