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* [PATCH] dm-persistent-data: free sm_metadata on failed create
@ 2016-11-30 23:56 Benjamin Marzinski
  2016-12-01 10:58 ` Edward Thornber
  0 siblings, 1 reply; 4+ messages in thread
From: Benjamin Marzinski @ 2016-11-30 23:56 UTC (permalink / raw)
  To: dm-devel; +Cc: Edward Thornber

In dm_sm_metadata_create we temporarily change the dm_space_map
operations from ops, whose destroy function deallocates the
sm_metadata, to bootstrap_ops, whose destroy function doesn't. If we
fail in dm_ll_new_metadata or sm_ll_extend, we exit back to
dm_tm_create_internal, which calls dm_sm_destroy with the intention
of freeing the sm_metadata, but it doesn't.

This patch sets the dm_space_map operations back to ops if
dm_sm_metadata_create fails when it is set to bootstrap_ops.

Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com>
---
 drivers/md/persistent-data/dm-space-map-metadata.c | 14 ++++++--------
 1 file changed, 6 insertions(+), 8 deletions(-)

diff --git a/drivers/md/persistent-data/dm-space-map-metadata.c b/drivers/md/persistent-data/dm-space-map-metadata.c
index 7e44005..20557e2 100644
--- a/drivers/md/persistent-data/dm-space-map-metadata.c
+++ b/drivers/md/persistent-data/dm-space-map-metadata.c
@@ -775,17 +775,15 @@ int dm_sm_metadata_create(struct dm_space_map *sm,
 	memcpy(&smm->sm, &bootstrap_ops, sizeof(smm->sm));
 
 	r = sm_ll_new_metadata(&smm->ll, tm);
+	if (!r) {
+		if (nr_blocks > DM_SM_METADATA_MAX_BLOCKS)
+			nr_blocks = DM_SM_METADATA_MAX_BLOCKS;
+		r = sm_ll_extend(&smm->ll, nr_blocks);
+	}
+	memcpy(&smm->sm, &ops, sizeof(smm->sm));
 	if (r)
 		return r;
 
-	if (nr_blocks > DM_SM_METADATA_MAX_BLOCKS)
-		nr_blocks = DM_SM_METADATA_MAX_BLOCKS;
-	r = sm_ll_extend(&smm->ll, nr_blocks);
-	if (r)
-		return r;
-
-	memcpy(&smm->sm, &ops, sizeof(smm->sm));
-
 	/*
 	 * Now we need to update the newly created data structures with the
 	 * allocated blocks that they were built from.
-- 
2.1.0

^ permalink raw reply related	[flat|nested] 4+ messages in thread

* Re: [PATCH] dm-persistent-data: free sm_metadata on failed create
  2016-11-30 23:56 [PATCH] dm-persistent-data: free sm_metadata on failed create Benjamin Marzinski
@ 2016-12-01 10:58 ` Edward Thornber
  2016-12-01 16:41   ` Mike Snitzer
  0 siblings, 1 reply; 4+ messages in thread
From: Edward Thornber @ 2016-12-01 10:58 UTC (permalink / raw)
  To: Benjamin Marzinski; +Cc: dm-devel

ack

On Wed, Nov 30, 2016 at 05:56:14PM -0600, Benjamin Marzinski wrote:
> In dm_sm_metadata_create we temporarily change the dm_space_map
> operations from ops, whose destroy function deallocates the
> sm_metadata, to bootstrap_ops, whose destroy function doesn't. If we
> fail in dm_ll_new_metadata or sm_ll_extend, we exit back to
> dm_tm_create_internal, which calls dm_sm_destroy with the intention
> of freeing the sm_metadata, but it doesn't.
> 
> This patch sets the dm_space_map operations back to ops if
> dm_sm_metadata_create fails when it is set to bootstrap_ops.
> 
> Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com>
> ---
>  drivers/md/persistent-data/dm-space-map-metadata.c | 14 ++++++--------
>  1 file changed, 6 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/md/persistent-data/dm-space-map-metadata.c b/drivers/md/persistent-data/dm-space-map-metadata.c
> index 7e44005..20557e2 100644
> --- a/drivers/md/persistent-data/dm-space-map-metadata.c
> +++ b/drivers/md/persistent-data/dm-space-map-metadata.c
> @@ -775,17 +775,15 @@ int dm_sm_metadata_create(struct dm_space_map *sm,
>  	memcpy(&smm->sm, &bootstrap_ops, sizeof(smm->sm));
>  
>  	r = sm_ll_new_metadata(&smm->ll, tm);
> +	if (!r) {
> +		if (nr_blocks > DM_SM_METADATA_MAX_BLOCKS)
> +			nr_blocks = DM_SM_METADATA_MAX_BLOCKS;
> +		r = sm_ll_extend(&smm->ll, nr_blocks);
> +	}
> +	memcpy(&smm->sm, &ops, sizeof(smm->sm));
>  	if (r)
>  		return r;
>  
> -	if (nr_blocks > DM_SM_METADATA_MAX_BLOCKS)
> -		nr_blocks = DM_SM_METADATA_MAX_BLOCKS;
> -	r = sm_ll_extend(&smm->ll, nr_blocks);
> -	if (r)
> -		return r;
> -
> -	memcpy(&smm->sm, &ops, sizeof(smm->sm));
> -
>  	/*
>  	 * Now we need to update the newly created data structures with the
>  	 * allocated blocks that they were built from.
> -- 
> 2.1.0
> 

^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: dm-persistent-data: free sm_metadata on failed create
  2016-12-01 10:58 ` Edward Thornber
@ 2016-12-01 16:41   ` Mike Snitzer
  2016-12-02 11:45     ` Edward Thornber
  0 siblings, 1 reply; 4+ messages in thread
From: Mike Snitzer @ 2016-12-01 16:41 UTC (permalink / raw)
  To: Edward Thornber; +Cc: dm-devel

Staged for 4.10 inclusion with a revised header, see:
https://git.kernel.org/cgit/linux/kernel/git/device-mapper/linux-dm.git/commit/?h=dm-4.10&id=b34af3050734ba53a7afa4f3ab9fe9d6bbfbf802

On Thu, Dec 01 2016 at  5:58am -0500,
Edward Thornber <thornber@redhat.com> wrote:

> ack
> 
> On Wed, Nov 30, 2016 at 05:56:14PM -0600, Benjamin Marzinski wrote:
> > In dm_sm_metadata_create we temporarily change the dm_space_map
> > operations from ops, whose destroy function deallocates the
> > sm_metadata, to bootstrap_ops, whose destroy function doesn't. If we
> > fail in dm_ll_new_metadata or sm_ll_extend, we exit back to
> > dm_tm_create_internal, which calls dm_sm_destroy with the intention
> > of freeing the sm_metadata, but it doesn't.
> > 
> > This patch sets the dm_space_map operations back to ops if
> > dm_sm_metadata_create fails when it is set to bootstrap_ops.
> > 
> > Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com>
> > ---
> >  drivers/md/persistent-data/dm-space-map-metadata.c | 14 ++++++--------
> >  1 file changed, 6 insertions(+), 8 deletions(-)
> > 
> > diff --git a/drivers/md/persistent-data/dm-space-map-metadata.c b/drivers/md/persistent-data/dm-space-map-metadata.c
> > index 7e44005..20557e2 100644
> > --- a/drivers/md/persistent-data/dm-space-map-metadata.c
> > +++ b/drivers/md/persistent-data/dm-space-map-metadata.c
> > @@ -775,17 +775,15 @@ int dm_sm_metadata_create(struct dm_space_map *sm,
> >  	memcpy(&smm->sm, &bootstrap_ops, sizeof(smm->sm));
> >  
> >  	r = sm_ll_new_metadata(&smm->ll, tm);
> > +	if (!r) {
> > +		if (nr_blocks > DM_SM_METADATA_MAX_BLOCKS)
> > +			nr_blocks = DM_SM_METADATA_MAX_BLOCKS;
> > +		r = sm_ll_extend(&smm->ll, nr_blocks);
> > +	}
> > +	memcpy(&smm->sm, &ops, sizeof(smm->sm));
> >  	if (r)
> >  		return r;
> >  
> > -	if (nr_blocks > DM_SM_METADATA_MAX_BLOCKS)
> > -		nr_blocks = DM_SM_METADATA_MAX_BLOCKS;
> > -	r = sm_ll_extend(&smm->ll, nr_blocks);
> > -	if (r)
> > -		return r;
> > -
> > -	memcpy(&smm->sm, &ops, sizeof(smm->sm));
> > -
> >  	/*
> >  	 * Now we need to update the newly created data structures with the
> >  	 * allocated blocks that they were built from.
> > -- 
> > 2.1.0
> > 
> 
> --
> dm-devel mailing list
> dm-devel@redhat.com
> https://www.redhat.com/mailman/listinfo/dm-devel

^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: dm-persistent-data: free sm_metadata on failed create
  2016-12-01 16:41   ` Mike Snitzer
@ 2016-12-02 11:45     ` Edward Thornber
  0 siblings, 0 replies; 4+ messages in thread
From: Edward Thornber @ 2016-12-02 11:45 UTC (permalink / raw)
  To: Mike Snitzer; +Cc: dm-devel

On Thu, Dec 01, 2016 at 11:41:05AM -0500, Mike Snitzer wrote:
> Staged for 4.10 inclusion with a revised header, see:
> https://git.kernel.org/cgit/linux/kernel/git/device-mapper/linux-dm.git/commit/?h=dm-4.10&id=b34af3050734ba53a7afa4f3ab9fe9d6bbfbf802

It's not urgent.  In general if something goes wrong with a persistent
data transaction we just abort and roll back.  So there are a lot of
error paths where we don't bother to repair metadata that's in the
doomed transaction.

^ permalink raw reply	[flat|nested] 4+ messages in thread

end of thread, other threads:[~2016-12-02 11:45 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2016-11-30 23:56 [PATCH] dm-persistent-data: free sm_metadata on failed create Benjamin Marzinski
2016-12-01 10:58 ` Edward Thornber
2016-12-01 16:41   ` Mike Snitzer
2016-12-02 11:45     ` Edward Thornber

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