On 2020/9/26 23:36, Eric Sandeen wrote:
> On 9/26/20 8:14 AM, xiakaixu1987@xxxxxxxxx wrote:
>> From: Kaixu Xia <kaixuxia@xxxxxxxxxxx>
>>
>> Nowadays the only things that the XFS_TRANS_DQ_DIRTY flag seems to do
>> are indicates the tp->t_dqinfo->dqs[XFS_QM_TRANS_{USR,GRP,PRJ}] values
>> changed and check in xfs_trans_apply_dquot_deltas() and the unreserve
>> variant xfs_trans_unreserve_and_mod_dquots(). Actually, we also can
>> use the tp->t_dqinfo value instead of the XFS_TRANS_DQ_DIRTY flag, that
>> is to say, we allocate the new tp->t_dqinfo only when the qtrx values
>> changed, so the tp->t_dqinfo value isn't NULL equals the XFS_TRANS_DQ_DIRTY
>> flag is set, we only need to check if tp->t_dqinfo == NULL in
>> xfs_trans_apply_dquot_deltas() and its unreserve variant to determine
>> whether lock all of the dquots and join them to the transaction.
>>
>> Signed-off-by: Kaixu Xia <kaixuxia@xxxxxxxxxxx>
>> ---
>> fs/xfs/libxfs/xfs_shared.h | 1 -
>> fs/xfs/xfs_inode.c | 8 +-------
>> fs/xfs/xfs_trans_dquot.c | 20 ++------------------
>> 3 files changed, 3 insertions(+), 26 deletions(-)
>>
>> diff --git a/fs/xfs/libxfs/xfs_shared.h b/fs/xfs/libxfs/xfs_shared.h
>> index c795ae47b3c9..8c61a461bf7b 100644
>> --- a/fs/xfs/libxfs/xfs_shared.h
>> +++ b/fs/xfs/libxfs/xfs_shared.h
>> @@ -62,7 +62,6 @@ void xfs_log_get_max_trans_res(struct xfs_mount *mp,
>> #define XFS_TRANS_SB_DIRTY 0x02 /* superblock is modified */
>> #define XFS_TRANS_PERM_LOG_RES 0x04 /* xact took a permanent log res */
>> #define XFS_TRANS_SYNC 0x08 /* make commit synchronous */
>> -#define XFS_TRANS_DQ_DIRTY 0x10 /* at least one dquot in trx dirty */
>> #define XFS_TRANS_RESERVE 0x20 /* OK to use reserved data blocks */
>> #define XFS_TRANS_NO_WRITECOUNT 0x40 /* do not elevate SB writecount */
>> #define XFS_TRANS_RES_FDBLKS 0x80 /* reserve newly freed blocks */
>> diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
>> index 49624973eecc..9108eed0ea45 100644
>> --- a/fs/xfs/xfs_inode.c
>> +++ b/fs/xfs/xfs_inode.c
>> @@ -941,7 +941,6 @@ xfs_dir_ialloc(
>> xfs_buf_t *ialloc_context = NULL;
>> int code;
>> void *dqinfo;
>> - uint tflags;
>>
>> tp = *tpp;
>> ASSERT(tp->t_flags & XFS_TRANS_PERM_LOG_RES);
>> @@ -1000,12 +999,9 @@ xfs_dir_ialloc(
>> * and attach it to the next transaction.
>> */
>> dqinfo = NULL;
>> - tflags = 0;
>> if (tp->t_dqinfo) {
>> dqinfo = (void *)tp->t_dqinfo;
>> tp->t_dqinfo = NULL;
>> - tflags = tp->t_flags & XFS_TRANS_DQ_DIRTY;
>> - tp->t_flags &= ~(XFS_TRANS_DQ_DIRTY);
>> }
>>
>> code = xfs_trans_roll(&tp);
>> @@ -1013,10 +1009,8 @@ xfs_dir_ialloc(
>> /*
>> * Re-attach the quota info that we detached from prev trx.
>> */
>> - if (dqinfo) {
>> + if (dqinfo)
>> tp->t_dqinfo = dqinfo;
>> - tp->t_flags |= tflags;
>> - }
>>
>> if (code) {
>> xfs_buf_relse(ialloc_context);
>> diff --git a/fs/xfs/xfs_trans_dquot.c b/fs/xfs/xfs_trans_dquot.c
>> index fe45b0c3970c..0ebfd7930382 100644
>> --- a/fs/xfs/xfs_trans_dquot.c
>> +++ b/fs/xfs/xfs_trans_dquot.c
>> @@ -84,13 +84,6 @@ xfs_trans_dup_dqinfo(
>>
>> xfs_trans_alloc_dqinfo(ntp);
>>
>> - /*
>> - * Because the quota blk reservation is carried forward,
>> - * it is also necessary to carry forward the DQ_DIRTY flag.
>> - */
>> - if (otp->t_flags & XFS_TRANS_DQ_DIRTY)
>> - ntp->t_flags |= XFS_TRANS_DQ_DIRTY;
>> -
>> for (j = 0; j < XFS_QM_TRANS_DQTYPES; j++) {
>> oqa = otp->t_dqinfo->dqs[j];
>> nqa = ntp->t_dqinfo->dqs[j];
>> @@ -143,9 +136,6 @@ xfs_trans_mod_dquot_byino(
>> xfs_is_quota_inode(&mp->m_sb, ip->i_ino))
>> return;
>>
>> - if (tp->t_dqinfo == NULL)
>> - xfs_trans_alloc_dqinfo(tp);
>> -
>
> I can't tell from the commit log or from a very quick read of the code why these
> allocations are being removed. Can we not get here with a NULL t_dqinfo?
> If not, why not? This seems like a change unrelated to the proposed
> "t_dqinfo set == XFS_TRANS_DQ_DIRTY" change.
Yeah, remove these allocations because I want to allocate the t_dqinfo only
when the tp->t_dqinfo->dqs[XFS_QM_TRANS_{USR,GRP,PRJ}] values changed, that
is to say, only do the allocation in xfs_trans_mod_dquot() function. Actually,
original these allocations are repeated, for example, the xfs_trans_mod_dquot_byino()
function call the xfs_trans_mod_dquot(), but both of them do the allocation,
so remove one of them may be reasonable.
>
> Also, while it seems clear to say that !t_dqinfo == !XFS_TRANS_DQ_DIRTY, is the
> converse true? Is it possible to have t_dqinfo set, but it's not dirty?>
> I think the answer is that when we free the transaction we set t_dqinfo to
> NULL again, but I'm not certain, and it's not obvious from the changelog...
Now we do the allocation in xfs_trans_mod_dquot() function and only have t_dqinfo
set when it is dirty.
Thanks,
Kaixu
>
> -Eric
>
--
kaixuxia
