[RFC PATCH] xfs: Properly retry failed dquot items in case of error during buffer writeback

[RFC PATCH] xfs: Properly retry failed dquot items in case of error during buffer writeback

[Carlos Maiolino]

Hi,

Once the fix for inode item writeback errors is already queued
(d3a304b62), I believe it's time to fix the same problem in dquot code.

Although there were no reports of users hitting this bug in dquot code
(at least none I've seen), the bug is there and I was already planning
to fix it when the correct approach to fix the inodes part was decided.

So, this is an RFC patch to fix the same problem in dquot code,
regarding failed buffers being unable to be resubmitted once they are
flush locked.

The semantics are quite similar to inode items path, although during
xfs_qm_dqflush_done(), I'm not sure if the changes I made are correct.

Comments much appreciated :)


BTW, This patch should be applied only over branch xfs-4.14-merge, it requires
my previous patches, which are not in the master branch yet.

Cheers.

Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com>
---
 fs/xfs/xfs_dquot.c      | 11 ++++++++---
 fs/xfs/xfs_dquot_item.c | 37 +++++++++++++++++++++++++++++++++++--
 2 files changed, 43 insertions(+), 5 deletions(-)

diff --git a/fs/xfs/xfs_dquot.c b/fs/xfs/xfs_dquot.c
index fd2ef8c2c9a7..8198c20212a2 100644
--- a/fs/xfs/xfs_dquot.c
+++ b/fs/xfs/xfs_dquot.c
@@ -987,14 +987,19 @@ xfs_qm_dqflush_done(
 	 * holding the lock before removing the dquot from the AIL.
 	 */
 	if ((lip->li_flags & XFS_LI_IN_AIL) &&
-	    lip->li_lsn == qip->qli_flush_lsn) {
+	   (lip->li_lsn == qip->qli_flush_lsn) ||
+	    lip->li_flags & XFS_LI_FAILED) {
 
 		/* xfs_trans_ail_delete() drops the AIL lock. */
 		spin_lock(&ailp->xa_lock);
-		if (lip->li_lsn == qip->qli_flush_lsn)
+		if (lip->li_lsn == qip->qli_flush_lsn) {
 			xfs_trans_ail_delete(ailp, lip, SHUTDOWN_CORRUPT_INCORE);
-		else
+		} else if (lip->li_flags & XFS_LI_FAILED) {
+			xfs_clear_li_failed(lip);
 			spin_unlock(&ailp->xa_lock);
+		} else {
+			spin_unlock(&ailp->xa_lock);
+		}
 	}
 
 	/*
diff --git a/fs/xfs/xfs_dquot_item.c b/fs/xfs/xfs_dquot_item.c
index 2c7a1629e064..35fd6d71bc42 100644
--- a/fs/xfs/xfs_dquot_item.c
+++ b/fs/xfs/xfs_dquot_item.c
@@ -137,6 +137,23 @@ xfs_qm_dqunpin_wait(
 	wait_event(dqp->q_pinwait, (atomic_read(&dqp->q_pincount) == 0));
 }
 
+/*
+ * Callback used to mark a buffer with XFS_LI_FAILED when items in the buffer
+ * have been failed during writeback
+ *
+ * this informs the AIL that the dquot is already flush locked on the next push,
+ * and acquires a hold on the buffer to ensure that it isn't reclaimed before
+ * dirty data makes it to disk.
+ */
+STATIC void
+xfs_dquot_item_error(
+	struct xfs_log_item	*lip,
+	struct xfs_buf		*bp)
+{
+	ASSERT(XFS_DQ_IS_LOCKED(DQUOT_ITEM(lip)->qli_item));
+	xfs_set_li_failed(lip, bp);
+}
+
 STATIC uint
 xfs_qm_dquot_logitem_push(
 	struct xfs_log_item	*lip,
@@ -144,13 +161,28 @@ xfs_qm_dquot_logitem_push(
 					      __acquires(&lip->li_ailp->xa_lock)
 {
 	struct xfs_dquot	*dqp = DQUOT_ITEM(lip)->qli_dquot;
-	struct xfs_buf		*bp = NULL;
+	struct xfs_buf		*bp = lip->li_buf;
 	uint			rval = XFS_ITEM_SUCCESS;
 	int			error;
 
 	if (atomic_read(&dqp->q_pincount) > 0)
 		return XFS_ITEM_PINNED;
 
+	/*
+	 * The buffer containing this item failed to be written back
+	 * previously. Resubmit the buffer for IO
+	 */
+	if (lip->li_flags & XFS_LI_FAILED) {
+		if (!xfs_buf_trylock(bp))
+			return XFS_ITEM_LOCKED;
+
+		if (!xfs_buf_resubmit_failed_buffers(bp, lip, buffer_list))
+			rval = XFS_ITEM_FLUSHING;
+
+		xfs_buf_unlock(bp);
+		return rval;
+	}
+
 	if (!xfs_dqlock_nowait(dqp))
 		return XFS_ITEM_LOCKED;
 
@@ -242,7 +274,8 @@ static const struct xfs_item_ops xfs_dquot_item_ops = {
 	.iop_unlock	= xfs_qm_dquot_logitem_unlock,
 	.iop_committed	= xfs_qm_dquot_logitem_committed,
 	.iop_push	= xfs_qm_dquot_logitem_push,
-	.iop_committing = xfs_qm_dquot_logitem_committing
+	.iop_committing = xfs_qm_dquot_logitem_committing,
+	.iop_error	= xfs_dquot_item_error
 };
 
 /*
-- 
2.13.5

Re: [RFC PATCH] xfs: Properly retry failed dquot items in case of error during buffer writeback

[Darrick J. Wong]

On Fri, Aug 25, 2017 at 02:07:52PM +0200, Carlos Maiolino wrote:
> Hi,
> 
> Once the fix for inode item writeback errors is already queued
> (d3a304b62), I believe it's time to fix the same problem in dquot code.
> 
> Although there were no reports of users hitting this bug in dquot code
> (at least none I've seen), the bug is there and I was already planning
> to fix it when the correct approach to fix the inodes part was decided.
> 
> So, this is an RFC patch to fix the same problem in dquot code,
> regarding failed buffers being unable to be resubmitted once they are
> flush locked.
> 
> The semantics are quite similar to inode items path, although during
> xfs_qm_dqflush_done(), I'm not sure if the changes I made are correct.
> 
> Comments much appreciated :)
> 
> 
> BTW, This patch should be applied only over branch xfs-4.14-merge, it requires
> my previous patches, which are not in the master branch yet.

Looks ok, but is there an xfstests case to cover this?

--D

> 
> Cheers.
> 
> Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com>
> ---
>  fs/xfs/xfs_dquot.c      | 11 ++++++++---
>  fs/xfs/xfs_dquot_item.c | 37 +++++++++++++++++++++++++++++++++++--
>  2 files changed, 43 insertions(+), 5 deletions(-)
> 
> diff --git a/fs/xfs/xfs_dquot.c b/fs/xfs/xfs_dquot.c
> index fd2ef8c2c9a7..8198c20212a2 100644
> --- a/fs/xfs/xfs_dquot.c
> +++ b/fs/xfs/xfs_dquot.c
> @@ -987,14 +987,19 @@ xfs_qm_dqflush_done(
>  	 * holding the lock before removing the dquot from the AIL.
>  	 */
>  	if ((lip->li_flags & XFS_LI_IN_AIL) &&
> -	    lip->li_lsn == qip->qli_flush_lsn) {
> +	   (lip->li_lsn == qip->qli_flush_lsn) ||
> +	    lip->li_flags & XFS_LI_FAILED) {
>  
>  		/* xfs_trans_ail_delete() drops the AIL lock. */
>  		spin_lock(&ailp->xa_lock);
> -		if (lip->li_lsn == qip->qli_flush_lsn)
> +		if (lip->li_lsn == qip->qli_flush_lsn) {
>  			xfs_trans_ail_delete(ailp, lip, SHUTDOWN_CORRUPT_INCORE);
> -		else
> +		} else if (lip->li_flags & XFS_LI_FAILED) {
> +			xfs_clear_li_failed(lip);
>  			spin_unlock(&ailp->xa_lock);
> +		} else {
> +			spin_unlock(&ailp->xa_lock);
> +		}
>  	}
>  
>  	/*
> diff --git a/fs/xfs/xfs_dquot_item.c b/fs/xfs/xfs_dquot_item.c
> index 2c7a1629e064..35fd6d71bc42 100644
> --- a/fs/xfs/xfs_dquot_item.c
> +++ b/fs/xfs/xfs_dquot_item.c
> @@ -137,6 +137,23 @@ xfs_qm_dqunpin_wait(
>  	wait_event(dqp->q_pinwait, (atomic_read(&dqp->q_pincount) == 0));
>  }
>  
> +/*
> + * Callback used to mark a buffer with XFS_LI_FAILED when items in the buffer
> + * have been failed during writeback
> + *
> + * this informs the AIL that the dquot is already flush locked on the next push,
> + * and acquires a hold on the buffer to ensure that it isn't reclaimed before
> + * dirty data makes it to disk.
> + */
> +STATIC void
> +xfs_dquot_item_error(
> +	struct xfs_log_item	*lip,
> +	struct xfs_buf		*bp)
> +{
> +	ASSERT(XFS_DQ_IS_LOCKED(DQUOT_ITEM(lip)->qli_item));
> +	xfs_set_li_failed(lip, bp);
> +}
> +
>  STATIC uint
>  xfs_qm_dquot_logitem_push(
>  	struct xfs_log_item	*lip,
> @@ -144,13 +161,28 @@ xfs_qm_dquot_logitem_push(
>  					      __acquires(&lip->li_ailp->xa_lock)
>  {
>  	struct xfs_dquot	*dqp = DQUOT_ITEM(lip)->qli_dquot;
> -	struct xfs_buf		*bp = NULL;
> +	struct xfs_buf		*bp = lip->li_buf;
>  	uint			rval = XFS_ITEM_SUCCESS;
>  	int			error;
>  
>  	if (atomic_read(&dqp->q_pincount) > 0)
>  		return XFS_ITEM_PINNED;
>  
> +	/*
> +	 * The buffer containing this item failed to be written back
> +	 * previously. Resubmit the buffer for IO
> +	 */
> +	if (lip->li_flags & XFS_LI_FAILED) {
> +		if (!xfs_buf_trylock(bp))
> +			return XFS_ITEM_LOCKED;
> +
> +		if (!xfs_buf_resubmit_failed_buffers(bp, lip, buffer_list))
> +			rval = XFS_ITEM_FLUSHING;
> +
> +		xfs_buf_unlock(bp);
> +		return rval;
> +	}
> +
>  	if (!xfs_dqlock_nowait(dqp))
>  		return XFS_ITEM_LOCKED;
>  
> @@ -242,7 +274,8 @@ static const struct xfs_item_ops xfs_dquot_item_ops = {
>  	.iop_unlock	= xfs_qm_dquot_logitem_unlock,
>  	.iop_committed	= xfs_qm_dquot_logitem_committed,
>  	.iop_push	= xfs_qm_dquot_logitem_push,
> -	.iop_committing = xfs_qm_dquot_logitem_committing
> +	.iop_committing = xfs_qm_dquot_logitem_committing,
> +	.iop_error	= xfs_dquot_item_error
>  };
>  
>  /*
> -- 
> 2.13.5
> 
> --
> To unsubscribe from this list: send the line "unsubscribe linux-xfs" in
> the body of a message to majordomo@vger.kernel.org
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Re: [RFC PATCH] xfs: Properly retry failed dquot items in case of error during buffer writeback

[Darrick J. Wong]

On Fri, Aug 25, 2017 at 10:04:01AM -0700, Darrick J. Wong wrote:
> On Fri, Aug 25, 2017 at 02:07:52PM +0200, Carlos Maiolino wrote:
> > Hi,
> > 
> > Once the fix for inode item writeback errors is already queued
> > (d3a304b62), I believe it's time to fix the same problem in dquot code.
> > 
> > Although there were no reports of users hitting this bug in dquot code
> > (at least none I've seen), the bug is there and I was already planning
> > to fix it when the correct approach to fix the inodes part was decided.
> > 
> > So, this is an RFC patch to fix the same problem in dquot code,
> > regarding failed buffers being unable to be resubmitted once they are
> > flush locked.
> > 
> > The semantics are quite similar to inode items path, although during
> > xfs_qm_dqflush_done(), I'm not sure if the changes I made are correct.
> > 
> > Comments much appreciated :)
> > 
> > 
> > BTW, This patch should be applied only over branch xfs-4.14-merge, it requires
> > my previous patches, which are not in the master branch yet.
> 
> Looks ok, but is there an xfstests case to cover this?

Then I tried compiling it, which broke, and then I went digging more than
I would've for an RFC:

> --D
> 
> > 
> > Cheers.
> > 
> > Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com>
> > ---
> >  fs/xfs/xfs_dquot.c      | 11 ++++++++---
> >  fs/xfs/xfs_dquot_item.c | 37 +++++++++++++++++++++++++++++++++++--
> >  2 files changed, 43 insertions(+), 5 deletions(-)
> > 
> > diff --git a/fs/xfs/xfs_dquot.c b/fs/xfs/xfs_dquot.c
> > index fd2ef8c2c9a7..8198c20212a2 100644
> > --- a/fs/xfs/xfs_dquot.c
> > +++ b/fs/xfs/xfs_dquot.c
> > @@ -987,14 +987,19 @@ xfs_qm_dqflush_done(
> >  	 * holding the lock before removing the dquot from the AIL.
> >  	 */
> >  	if ((lip->li_flags & XFS_LI_IN_AIL) &&
> > -	    lip->li_lsn == qip->qli_flush_lsn) {
> > +	   (lip->li_lsn == qip->qli_flush_lsn) ||
> > +	    lip->li_flags & XFS_LI_FAILED) {

...come to think of it, shouldn't there be a couple extra pairs of parentheses
in this somewhere?...

> >  
> >  		/* xfs_trans_ail_delete() drops the AIL lock. */
> >  		spin_lock(&ailp->xa_lock);
> > -		if (lip->li_lsn == qip->qli_flush_lsn)
> > +		if (lip->li_lsn == qip->qli_flush_lsn) {
> >  			xfs_trans_ail_delete(ailp, lip, SHUTDOWN_CORRUPT_INCORE);
> > -		else
> > +		} else if (lip->li_flags & XFS_LI_FAILED) {
> > +			xfs_clear_li_failed(lip);
> >  			spin_unlock(&ailp->xa_lock);
> > +		} else {
> > +			spin_unlock(&ailp->xa_lock);
> > +		}
> >  	}
> >  
> >  	/*
> > diff --git a/fs/xfs/xfs_dquot_item.c b/fs/xfs/xfs_dquot_item.c
> > index 2c7a1629e064..35fd6d71bc42 100644
> > --- a/fs/xfs/xfs_dquot_item.c
> > +++ b/fs/xfs/xfs_dquot_item.c
> > @@ -137,6 +137,23 @@ xfs_qm_dqunpin_wait(
> >  	wait_event(dqp->q_pinwait, (atomic_read(&dqp->q_pincount) == 0));
> >  }
> >  
> > +/*
> > + * Callback used to mark a buffer with XFS_LI_FAILED when items in the buffer
> > + * have been failed during writeback
> > + *
> > + * this informs the AIL that the dquot is already flush locked on the next push,
> > + * and acquires a hold on the buffer to ensure that it isn't reclaimed before
> > + * dirty data makes it to disk.
> > + */
> > +STATIC void
> > +xfs_dquot_item_error(
> > +	struct xfs_log_item	*lip,
> > +	struct xfs_buf		*bp)
> > +{
> > +	ASSERT(XFS_DQ_IS_LOCKED(DQUOT_ITEM(lip)->qli_item));

...and isn't this qli_dquot, not qli_item?

(Does this compile at all?)

--D

> > +	xfs_set_li_failed(lip, bp);
> > +}
> > +
> >  STATIC uint
> >  xfs_qm_dquot_logitem_push(
> >  	struct xfs_log_item	*lip,
> > @@ -144,13 +161,28 @@ xfs_qm_dquot_logitem_push(
> >  					      __acquires(&lip->li_ailp->xa_lock)
> >  {
> >  	struct xfs_dquot	*dqp = DQUOT_ITEM(lip)->qli_dquot;
> > -	struct xfs_buf		*bp = NULL;
> > +	struct xfs_buf		*bp = lip->li_buf;
> >  	uint			rval = XFS_ITEM_SUCCESS;
> >  	int			error;
> >  
> >  	if (atomic_read(&dqp->q_pincount) > 0)
> >  		return XFS_ITEM_PINNED;
> >  
> > +	/*
> > +	 * The buffer containing this item failed to be written back
> > +	 * previously. Resubmit the buffer for IO
> > +	 */
> > +	if (lip->li_flags & XFS_LI_FAILED) {
> > +		if (!xfs_buf_trylock(bp))
> > +			return XFS_ITEM_LOCKED;
> > +
> > +		if (!xfs_buf_resubmit_failed_buffers(bp, lip, buffer_list))
> > +			rval = XFS_ITEM_FLUSHING;
> > +
> > +		xfs_buf_unlock(bp);
> > +		return rval;
> > +	}
> > +
> >  	if (!xfs_dqlock_nowait(dqp))
> >  		return XFS_ITEM_LOCKED;
> >  
> > @@ -242,7 +274,8 @@ static const struct xfs_item_ops xfs_dquot_item_ops = {
> >  	.iop_unlock	= xfs_qm_dquot_logitem_unlock,
> >  	.iop_committed	= xfs_qm_dquot_logitem_committed,
> >  	.iop_push	= xfs_qm_dquot_logitem_push,
> > -	.iop_committing = xfs_qm_dquot_logitem_committing
> > +	.iop_committing = xfs_qm_dquot_logitem_committing,
> > +	.iop_error	= xfs_dquot_item_error
> >  };
> >  
> >  /*
> > -- 
> > 2.13.5
> > 
> > --
> > To unsubscribe from this list: send the line "unsubscribe linux-xfs" in
> > the body of a message to majordomo@vger.kernel.org
> > More majordomo info at  http://vger.kernel.org/majordomo-info.html
> --
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Re: [RFC PATCH] xfs: Properly retry failed dquot items in case of error during buffer writeback

[Carlos Maiolino]

Hi Darrick.


> > > BTW, This patch should be applied only over branch xfs-4.14-merge, it requires
> > > my previous patches, which are not in the master branch yet.
> > 
> > Looks ok, but is there an xfstests case to cover this?
> 

No,

I still don't have a xfstests to cover it, I couldn't reproduce the problem with
dquots yet, I'll focus more on this soon.

> > >  	if ((lip->li_flags & XFS_LI_IN_AIL) &&
> > > -	    lip->li_lsn == qip->qli_flush_lsn) {
> > > +	   (lip->li_lsn == qip->qli_flush_lsn) ||
> > > +	    lip->li_flags & XFS_LI_FAILED) {
> 

> ...come to think of it, shouldn't there be a couple extra pairs of parentheses
> in this somewhere?...
> 
IIRC there is no need, && has a higher precedenc over ||, but I really don't
mind to add an extra pair of () here.

> > >  
> > >  		/* xfs_trans_ail_delete() drops the AIL lock. */
> > >  		spin_lock(&ailp->xa_lock);
> > > -		if (lip->li_lsn == qip->qli_flush_lsn)
> > > +		if (lip->li_lsn == qip->qli_flush_lsn) {
> > >  			xfs_trans_ail_delete(ailp, lip, SHUTDOWN_CORRUPT_INCORE);
> > > -		else
> > > +		} else if (lip->li_flags & XFS_LI_FAILED) {
> > > +			xfs_clear_li_failed(lip);
> > >  			spin_unlock(&ailp->xa_lock);
> > > +		} else {
> > > +			spin_unlock(&ailp->xa_lock);
> > > +		}
> > >  	}
> > >  
> > >  	/*
> > > diff --git a/fs/xfs/xfs_dquot_item.c b/fs/xfs/xfs_dquot_item.c
> > > index 2c7a1629e064..35fd6d71bc42 100644
> > > --- a/fs/xfs/xfs_dquot_item.c
> > > +++ b/fs/xfs/xfs_dquot_item.c
> > > @@ -137,6 +137,23 @@ xfs_qm_dqunpin_wait(
> > >  	wait_event(dqp->q_pinwait, (atomic_read(&dqp->q_pincount) == 0));
> > >  }
> > >  
> > > +/*
> > > + * Callback used to mark a buffer with XFS_LI_FAILED when items in the buffer
> > > + * have been failed during writeback
> > > + *
> > > + * this informs the AIL that the dquot is already flush locked on the next push,
> > > + * and acquires a hold on the buffer to ensure that it isn't reclaimed before
> > > + * dirty data makes it to disk.
> > > + */
> > > +STATIC void
> > > +xfs_dquot_item_error(
> > > +	struct xfs_log_item	*lip,
> > > +	struct xfs_buf		*bp)
> > > +{
> > > +	ASSERT(XFS_DQ_IS_LOCKED(DQUOT_ITEM(lip)->qli_item));
> 
> ...and isn't this qli_dquot, not qli_item?
> 

Yup, you are right.

> (Does this compile at all?)
> 

Yes, it compiled the way it was :P

I'll wait for some extra comments here, before submitting a non-RFC patch, and
will think about how can I reproduce it on xfstests, maybe filling the
filesystem and then playing with quotas.

Thanks for the review Darrick.

Cheers.

-- 
Carlos

Re: [RFC PATCH] xfs: Properly retry failed dquot items in case of error during buffer writeback

[Darrick J. Wong]

On Mon, Aug 28, 2017 at 11:20:30AM +0200, Carlos Maiolino wrote:
> Hi Darrick.
> 
> 
> > > > BTW, This patch should be applied only over branch xfs-4.14-merge, it requires
> > > > my previous patches, which are not in the master branch yet.
> > > 
> > > Looks ok, but is there an xfstests case to cover this?
> > 
> 
> No,
> 
> I still don't have a xfstests to cover it, I couldn't reproduce the problem with
> dquots yet, I'll focus more on this soon.
> 
> > > >  	if ((lip->li_flags & XFS_LI_IN_AIL) &&
> > > > -	    lip->li_lsn == qip->qli_flush_lsn) {
> > > > +	   (lip->li_lsn == qip->qli_flush_lsn) ||
> > > > +	    lip->li_flags & XFS_LI_FAILED) {
> > 
> 
> > ...come to think of it, shouldn't there be a couple extra pairs of parentheses
> > in this somewhere?...
> > 
> IIRC there is no need, && has a higher precedenc over ||, but I really don't
> mind to add an extra pair of () here.
> 
> > > >  
> > > >  		/* xfs_trans_ail_delete() drops the AIL lock. */
> > > >  		spin_lock(&ailp->xa_lock);
> > > > -		if (lip->li_lsn == qip->qli_flush_lsn)
> > > > +		if (lip->li_lsn == qip->qli_flush_lsn) {
> > > >  			xfs_trans_ail_delete(ailp, lip, SHUTDOWN_CORRUPT_INCORE);
> > > > -		else
> > > > +		} else if (lip->li_flags & XFS_LI_FAILED) {
> > > > +			xfs_clear_li_failed(lip);
> > > >  			spin_unlock(&ailp->xa_lock);
> > > > +		} else {
> > > > +			spin_unlock(&ailp->xa_lock);
> > > > +		}
> > > >  	}
> > > >  
> > > >  	/*
> > > > diff --git a/fs/xfs/xfs_dquot_item.c b/fs/xfs/xfs_dquot_item.c
> > > > index 2c7a1629e064..35fd6d71bc42 100644
> > > > --- a/fs/xfs/xfs_dquot_item.c
> > > > +++ b/fs/xfs/xfs_dquot_item.c
> > > > @@ -137,6 +137,23 @@ xfs_qm_dqunpin_wait(
> > > >  	wait_event(dqp->q_pinwait, (atomic_read(&dqp->q_pincount) == 0));
> > > >  }
> > > >  
> > > > +/*
> > > > + * Callback used to mark a buffer with XFS_LI_FAILED when items in the buffer
> > > > + * have been failed during writeback
> > > > + *
> > > > + * this informs the AIL that the dquot is already flush locked on the next push,
> > > > + * and acquires a hold on the buffer to ensure that it isn't reclaimed before
> > > > + * dirty data makes it to disk.
> > > > + */
> > > > +STATIC void
> > > > +xfs_dquot_item_error(
> > > > +	struct xfs_log_item	*lip,
> > > > +	struct xfs_buf		*bp)
> > > > +{
> > > > +	ASSERT(XFS_DQ_IS_LOCKED(DQUOT_ITEM(lip)->qli_item));
> > 
> > ...and isn't this qli_dquot, not qli_item?
> > 
> 
> Yup, you are right.
> 
> > (Does this compile at all?)
> > 
> 
> Yes, it compiled the way it was :P
> 
> I'll wait for some extra comments here, before submitting a non-RFC patch, and
> will think about how can I reproduce it on xfstests, maybe filling the
> filesystem and then playing with quotas.

Has there been a rework of this patch?

--D

> 
> Thanks for the review Darrick.
> 
> Cheers.
> 
> -- 
> Carlos
> --
> To unsubscribe from this list: send the line "unsubscribe linux-xfs" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

Re: [RFC PATCH] xfs: Properly retry failed dquot items in case of error during buffer writeback

[Carlos Maiolino]

> > Yup, you are right.
> > 
> > > (Does this compile at all?)
> > > 
> > 
> > Yes, it compiled the way it was :P
> > 
> > I'll wait for some extra comments here, before submitting a non-RFC patch, and
> > will think about how can I reproduce it on xfstests, maybe filling the
> > filesystem and then playing with quotas.
> 
> Has there been a rework of this patch?

I missed this e-mail somehow, I'll rework and submit the non-RFC patch

> 
> --D
> 
> > 
> > Thanks for the review Darrick.
> > 
> > Cheers.
> > 
> > -- 
> > Carlos
> > --
> > To unsubscribe from this list: send the line "unsubscribe linux-xfs" in
> > the body of a message to majordomo@vger.kernel.org
> > More majordomo info at  http://vger.kernel.org/majordomo-info.html
> --
> To unsubscribe from this list: send the line "unsubscribe linux-xfs" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

-- 
Carlos

Re: [RFC PATCH] xfs: Properly retry failed dquot items in case of error during buffer writeback

[Hou Tao]

Hi Carlos,

On 2017/8/28 17:20, Carlos Maiolino wrote:
> Hi Darrick.
> 
> 
>>>> BTW, This patch should be applied only over branch xfs-4.14-merge, it requires
>>>> my previous patches, which are not in the master branch yet.
>>>
>>> Looks ok, but is there an xfstests case to cover this?
>>
> 
> No,
> 
> I still don't have a xfstests to cover it, I couldn't reproduce the problem with
> dquots yet, I'll focus more on this soon.
I had written an xfstest case for the umount hang problem which is caused by the
writeback of the dquota update, and it can be reproduced reliably. If you don't mind,
i will clean it up and post to xfstest maillist this week.

Regards,

Tao
> 
>>>>  	if ((lip->li_flags & XFS_LI_IN_AIL) &&
>>>> -	    lip->li_lsn == qip->qli_flush_lsn) {
>>>> +	   (lip->li_lsn == qip->qli_flush_lsn) ||
>>>> +	    lip->li_flags & XFS_LI_FAILED) {
>>
> 
>> ...come to think of it, shouldn't there be a couple extra pairs of parentheses
>> in this somewhere?...
>>
> IIRC there is no need, && has a higher precedenc over ||, but I really don't
> mind to add an extra pair of () here.
> 
>>>>  
>>>>  		/* xfs_trans_ail_delete() drops the AIL lock. */
>>>>  		spin_lock(&ailp->xa_lock);
>>>> -		if (lip->li_lsn == qip->qli_flush_lsn)
>>>> +		if (lip->li_lsn == qip->qli_flush_lsn) {
>>>>  			xfs_trans_ail_delete(ailp, lip, SHUTDOWN_CORRUPT_INCORE);
>>>> -		else
>>>> +		} else if (lip->li_flags & XFS_LI_FAILED) {
>>>> +			xfs_clear_li_failed(lip);
>>>>  			spin_unlock(&ailp->xa_lock);
>>>> +		} else {
>>>> +			spin_unlock(&ailp->xa_lock);
>>>> +		}
>>>>  	}
>>>>  
>>>>  	/*
>>>> diff --git a/fs/xfs/xfs_dquot_item.c b/fs/xfs/xfs_dquot_item.c
>>>> index 2c7a1629e064..35fd6d71bc42 100644
>>>> --- a/fs/xfs/xfs_dquot_item.c
>>>> +++ b/fs/xfs/xfs_dquot_item.c
>>>> @@ -137,6 +137,23 @@ xfs_qm_dqunpin_wait(
>>>>  	wait_event(dqp->q_pinwait, (atomic_read(&dqp->q_pincount) == 0));
>>>>  }
>>>>  
>>>> +/*
>>>> + * Callback used to mark a buffer with XFS_LI_FAILED when items in the buffer
>>>> + * have been failed during writeback
>>>> + *
>>>> + * this informs the AIL that the dquot is already flush locked on the next push,
>>>> + * and acquires a hold on the buffer to ensure that it isn't reclaimed before
>>>> + * dirty data makes it to disk.
>>>> + */
>>>> +STATIC void
>>>> +xfs_dquot_item_error(
>>>> +	struct xfs_log_item	*lip,
>>>> +	struct xfs_buf		*bp)
>>>> +{
>>>> +	ASSERT(XFS_DQ_IS_LOCKED(DQUOT_ITEM(lip)->qli_item));
>>
>> ...and isn't this qli_dquot, not qli_item?
>>
> 
> Yup, you are right.
> 
>> (Does this compile at all?)
>>
> 
> Yes, it compiled the way it was :P
> 
> I'll wait for some extra comments here, before submitting a non-RFC patch, and
> will think about how can I reproduce it on xfstests, maybe filling the
> filesystem and then playing with quotas.
> 
> Thanks for the review Darrick.
> 
> Cheers.
> 

Re: [RFC PATCH] xfs: Properly retry failed dquot items in case of error during buffer writeback

[Darrick J. Wong]

On Mon, Oct 16, 2017 at 11:05:42AM +0800, Hou Tao wrote:
> Hi Carlos,
> 
> On 2017/8/28 17:20, Carlos Maiolino wrote:
> > Hi Darrick.
> > 
> > 
> >>>> BTW, This patch should be applied only over branch xfs-4.14-merge, it requires
> >>>> my previous patches, which are not in the master branch yet.
> >>>
> >>> Looks ok, but is there an xfstests case to cover this?
> >>
> > 
> > No,
> > 
> > I still don't have a xfstests to cover it, I couldn't reproduce the problem with
> > dquots yet, I'll focus more on this soon.
> I had written an xfstest case for the umount hang problem which is caused by the
> writeback of the dquota update, and it can be reproduced reliably. If you don't mind,
> i will clean it up and post to xfstest maillist this week.

I look forward to reviewing it.

--D

> 
> Regards,
> 
> Tao
> > 
> >>>>  	if ((lip->li_flags & XFS_LI_IN_AIL) &&
> >>>> -	    lip->li_lsn == qip->qli_flush_lsn) {
> >>>> +	   (lip->li_lsn == qip->qli_flush_lsn) ||
> >>>> +	    lip->li_flags & XFS_LI_FAILED) {
> >>
> > 
> >> ...come to think of it, shouldn't there be a couple extra pairs of parentheses
> >> in this somewhere?...
> >>
> > IIRC there is no need, && has a higher precedenc over ||, but I really don't
> > mind to add an extra pair of () here.
> > 
> >>>>  
> >>>>  		/* xfs_trans_ail_delete() drops the AIL lock. */
> >>>>  		spin_lock(&ailp->xa_lock);
> >>>> -		if (lip->li_lsn == qip->qli_flush_lsn)
> >>>> +		if (lip->li_lsn == qip->qli_flush_lsn) {
> >>>>  			xfs_trans_ail_delete(ailp, lip, SHUTDOWN_CORRUPT_INCORE);
> >>>> -		else
> >>>> +		} else if (lip->li_flags & XFS_LI_FAILED) {
> >>>> +			xfs_clear_li_failed(lip);
> >>>>  			spin_unlock(&ailp->xa_lock);
> >>>> +		} else {
> >>>> +			spin_unlock(&ailp->xa_lock);
> >>>> +		}
> >>>>  	}
> >>>>  
> >>>>  	/*
> >>>> diff --git a/fs/xfs/xfs_dquot_item.c b/fs/xfs/xfs_dquot_item.c
> >>>> index 2c7a1629e064..35fd6d71bc42 100644
> >>>> --- a/fs/xfs/xfs_dquot_item.c
> >>>> +++ b/fs/xfs/xfs_dquot_item.c
> >>>> @@ -137,6 +137,23 @@ xfs_qm_dqunpin_wait(
> >>>>  	wait_event(dqp->q_pinwait, (atomic_read(&dqp->q_pincount) == 0));
> >>>>  }
> >>>>  
> >>>> +/*
> >>>> + * Callback used to mark a buffer with XFS_LI_FAILED when items in the buffer
> >>>> + * have been failed during writeback
> >>>> + *
> >>>> + * this informs the AIL that the dquot is already flush locked on the next push,
> >>>> + * and acquires a hold on the buffer to ensure that it isn't reclaimed before
> >>>> + * dirty data makes it to disk.
> >>>> + */
> >>>> +STATIC void
> >>>> +xfs_dquot_item_error(
> >>>> +	struct xfs_log_item	*lip,
> >>>> +	struct xfs_buf		*bp)
> >>>> +{
> >>>> +	ASSERT(XFS_DQ_IS_LOCKED(DQUOT_ITEM(lip)->qli_item));
> >>
> >> ...and isn't this qli_dquot, not qli_item?
> >>
> > 
> > Yup, you are right.
> > 
> >> (Does this compile at all?)
> >>
> > 
> > Yes, it compiled the way it was :P
> > 
> > I'll wait for some extra comments here, before submitting a non-RFC patch, and
> > will think about how can I reproduce it on xfstests, maybe filling the
> > filesystem and then playing with quotas.
> > 
> > Thanks for the review Darrick.
> > 
> > Cheers.
> > 
> 
> --
> To unsubscribe from this list: send the line "unsubscribe linux-xfs" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

Re: [RFC PATCH] xfs: Properly retry failed dquot items in case of error during buffer writeback

[Carlos Maiolino]

Hi,
> > 
> > I still don't have a xfstests to cover it, I couldn't reproduce the problem with
> > dquots yet, I'll focus more on this soon.
> I had written an xfstest case for the umount hang problem which is caused by the
> writeback of the dquota update, and it can be reproduced reliably. If you don't mind,
> i will clean it up and post to xfstest maillist this week.
> 

Same thing, I missed this e-mail.

If you haven't already, go for it, I'll test my patch against it too.

Cheers


-- 
Carlos