[PATCH][SRU][BIONIC] UBUNTU: SAUCE: (noup) Update zfs to 0.7.5-1ubuntu16.6

[Colin Ian King]

On 04/06/2019 16:45, Connor Kuehl wrote:
> On 5/30/19 5:57 AM, Colin King wrote:
>> From: Colin Ian King <colin.king at canonical.com>
>>
>> https://bugs.launchpad.net/bugs/1772412
>>
>> Sync from zfs 0.7.5-1ubuntu16.6 that contains a backport of upstream zfs
>> commit 77d8a0f1a4d0b2f59cee63088f7987cb38e66538 ("Fix hung z_zvol tasks
>> during 'zfs receive'").
> 
> Should this still be prefixed with "UBUNTU: SAUCE: (noup)" if this fix
> is in upstream ZFS?

These special ZFS/SPL patches are auto-generated from a script that
grabs the dkms source package and generates a delta from the current
code and the new updated dkms source. We've always accepted these
patches in this format in the past.

> 
> I'm not sure if this is a side effect of how this package is synced, but
> I think we should also carry provenance from here:
> https://github.com/zfsonlinux/zfs/commit/77d8a0f1a4d0b2f59cee63088f7987cb38e66538
> 
>>
>> Adds a dedicated, per-pool, prefetch taskq to prevent the traverse
>> code from monopolizing the global (and limited) system_taskq by
>> inappropriately scheduling long running tasks on it. This fixes
>> z_zvol hung tasks when performing large I/O operations, for example
>> when performing huge ZFS send/receives (on slow media).
>>
>> Signed-off-by: Colin Ian King <colin.king at canonical.com>
>> ---
>>  zfs/META                      |  2 +-
>>  zfs/include/sys/spa_impl.h    |  1 +
>>  zfs/module/zfs/dmu_traverse.c |  3 ++-
>>  zfs/module/zfs/spa.c          | 13 +++++++++++++
>>  4 files changed, 17 insertions(+), 2 deletions(-)
>>
>> diff --git a/zfs/META b/zfs/META
>> index 9864f8f..0823859 100644
>> --- a/zfs/META
>> +++ b/zfs/META
>> @@ -2,7 +2,7 @@ Meta:         1
>>  Name:         zfs
>>  Branch:       1.0
>>  Version:      0.7.5
>> -Release:      1ubuntu16.5
>> +Release:      1ubuntu16.6
>>  Release-Tags: relext
>>  License:      CDDL
>>  Author:       OpenZFS on Linux
>> diff --git a/zfs/include/sys/spa_impl.h b/zfs/include/sys/spa_impl.h
>> index 06de244..34b1199 100644
>> --- a/zfs/include/sys/spa_impl.h
>> +++ b/zfs/include/sys/spa_impl.h
>> @@ -275,6 +275,7 @@ struct spa {
>>  	spa_stats_t	spa_stats;		/* assorted spa statistics */
>>  	hrtime_t	spa_ccw_fail_time;	/* Conf cache write fail time */
>>  	taskq_t		*spa_zvol_taskq;	/* Taskq for minor management */
>> +	taskq_t		*spa_prefetch_taskq;	/* Taskq for prefetch threads */
>>  	uint64_t	spa_multihost;		/* multihost aware (mmp) */
>>  	mmp_thread_t	spa_mmp;		/* multihost mmp thread */
>>  
>> diff --git a/zfs/module/zfs/dmu_traverse.c b/zfs/module/zfs/dmu_traverse.c
>> index 62f770e..c9171ee 100644
>> --- a/zfs/module/zfs/dmu_traverse.c
>> +++ b/zfs/module/zfs/dmu_traverse.c
>> @@ -31,6 +31,7 @@
>>  #include <sys/dsl_pool.h>
>>  #include <sys/dnode.h>
>>  #include <sys/spa.h>
>> +#include <sys/spa_impl.h>
>>  #include <sys/zio.h>
>>  #include <sys/dmu_impl.h>
>>  #include <sys/sa.h>
>> @@ -626,7 +627,7 @@ traverse_impl(spa_t *spa, dsl_dataset_t *ds, uint64_t objset, blkptr_t *rootbp,
>>  	}
>>  
>>  	if (!(flags & TRAVERSE_PREFETCH_DATA) ||
>> -	    taskq_dispatch(system_taskq, traverse_prefetch_thread,
>> +	    taskq_dispatch(spa->spa_prefetch_taskq, traverse_prefetch_thread,
>>  	    td, TQ_NOQUEUE) == TASKQID_INVALID)
>>  		pd->pd_exited = B_TRUE;
>>  
>> diff --git a/zfs/module/zfs/spa.c b/zfs/module/zfs/spa.c
>> index 00587d8..b777afc 100644
>> --- a/zfs/module/zfs/spa.c
>> +++ b/zfs/module/zfs/spa.c
>> @@ -1183,6 +1183,14 @@ spa_activate(spa_t *spa, int mode)
>>  	    1, INT_MAX, 0);
>>  
>>  	/*
>> +	 * Taskq dedicated to prefetcher threads: this is used to prevent the
>> +	 * pool traverse code from monopolizing the global (and limited)
>> +	 * system_taskq by inappropriately scheduling long running tasks on it.
>> +	 */
>> +	spa->spa_prefetch_taskq = taskq_create("z_prefetch", boot_ncpus,
>> +	    defclsyspri, 1, INT_MAX, TASKQ_DYNAMIC);
>> +
>> +	/*
>>  	 * The taskq to upgrade datasets in this pool. Currently used by
>>  	 * feature SPA_FEATURE_USEROBJ_ACCOUNTING.
>>  	 */
>> @@ -1211,6 +1219,11 @@ spa_deactivate(spa_t *spa)
>>  		spa->spa_zvol_taskq = NULL;
>>  	}
>>  
>> +	if (spa->spa_prefetch_taskq) {
>> +		taskq_destroy(spa->spa_prefetch_taskq);
>> +		spa->spa_prefetch_taskq = NULL;
>> +	}
>> +
>>  	if (spa->spa_upgrade_taskq) {
>>  		taskq_destroy(spa->spa_upgrade_taskq);
>>  		spa->spa_upgrade_taskq = NULL;
>>
> 
>