On 16.10.19 г. 10:31 ч., Qu Wenruo wrote:
> [BUG]
> For btrfs:qgroup_meta_reserve event, the trace event can output garbage:
> qgroup_meta_reserve: 9c7f6acc-b342-4037-bc47-7f6e4d2232d7: refroot=5(FS_TREE)
> type=DATA diff=2
> qgroup_meta_reserve: 9c7f6acc-b342-4037-bc47-7f6e4d2232d7: refroot=5(FS_TREE)
> type=0x258792 diff=2
>
> Since we're in qgroup_meta_reserve() trace event, the @type should never
> be DATA, while diff must be aligned to sectorsize (4K in this case).
>
> Only UUID and refroot is correct.
>
> [CAUSE]
> There are two causes for this bug:
>
> - Bad parameter order
> For trace event btrfs:qgroup_meta_reserve, we're passing wrong
> parameters.
>
> The correct parameters are:
> struct btrfs_root, s64 diff, int type.
>
> However the used order is:
> struct btrfs_root, int type, s64 diff.
>
> - @type is not even assigned
> What I was doing !? /facepalm
>
> [FIX]
> Fix the super stupid bug.
>
> Now everything works fine:
> qgroup_meta_reserve: 0477ad60-9aeb-4040-8a03-1900844d46ba: refroot=5(FS_TREE)
> type=META_PERTRANS diff=81920
> qgroup_meta_reserve: 0477ad60-9aeb-4040-8a03-1900844d46ba: refroot=5(FS_TREE)
> type=META_PREALLOC diff=16384
> qgroup_meta_reserve: 0477ad60-9aeb-4040-8a03-1900844d46ba: refroot=5(FS_TREE)
> type=META_PREALLOC diff=0
> qgroup_meta_reserve: 0477ad60-9aeb-4040-8a03-1900844d46ba: refroot=5(FS_TREE)
> type=META_PREALLOC diff=16384
> qgroup_meta_reserve: 0477ad60-9aeb-4040-8a03-1900844d46ba: refroot=5(FS_TREE)
> type=META_PREALLOC diff=-16384
> qgroup_meta_reserve: 0477ad60-9aeb-4040-8a03-1900844d46ba: refroot=5(FS_TREE)
> type=META_PREALLOC diff=16384
> qgroup_meta_reserve: 0477ad60-9aeb-4040-8a03-1900844d46ba: refroot=5(FS_TREE)
> type=META_PREALLOC diff=-16384
> qgroup_meta_reserve: 0477ad60-9aeb-4040-8a03-1900844d46ba: refroot=5(FS_TREE)
> type=META_PREALLOC diff=16384
> qgroup_meta_reserve: 0477ad60-9aeb-4040-8a03-1900844d46ba: refroot=5(FS_TREE)
> type=META_PREALLOC diff=-16384
>
> Fixes: 4ee0d8832c2e ("btrfs: qgroup: Update trace events for metadata
> reservation")
> Signed-off-by: Qu Wenruo <[email protected]>
Reviewed-by: Nikolay Borisov <[email protected]>
