diff options
| -rw-r--r-- | module/zfs/zvol.c | 99 |
1 files changed, 89 insertions, 10 deletions
diff --git a/module/zfs/zvol.c b/module/zfs/zvol.c index cddc43c7c..8bc0a608c 100644 --- a/module/zfs/zvol.c +++ b/module/zfs/zvol.c @@ -1482,6 +1482,32 @@ zvol_rename_minor(zvol_state_t *zv, const char *newname) set_disk_ro(zv->zv_disk, readonly); } +typedef struct minors_job { + list_t *list; + list_node_t link; + /* input */ + char *name; + /* output */ + int error; +} minors_job_t; + +/* + * Prefetch zvol dnodes for the minors_job + */ +static void +zvol_prefetch_minors_impl(void *arg) +{ + minors_job_t *job = arg; + char *dsname = job->name; + objset_t *os = NULL; + + job->error = dmu_objset_own(dsname, DMU_OST_ZVOL, B_TRUE, zvol_tag, + &os); + if (job->error == 0) { + dmu_prefetch(os, ZVOL_OBJ, 0, 0, 0, ZIO_PRIORITY_SYNC_READ); + dmu_objset_disown(os, zvol_tag); + } +} /* * Mask errors to continue dmu_objset_find() traversal @@ -1489,7 +1515,9 @@ zvol_rename_minor(zvol_state_t *zv, const char *newname) static int zvol_create_snap_minor_cb(const char *dsname, void *arg) { - const char *name = (const char *)arg; + minors_job_t *j = arg; + list_t *minors_list = j->list; + const char *name = j->name; ASSERT0(MUTEX_HELD(&spa_namespace_lock)); @@ -1502,7 +1530,19 @@ zvol_create_snap_minor_cb(const char *dsname, void *arg) dprintf("zvol_create_snap_minor_cb(): " "%s is not a shapshot name\n", dsname); } else { - (void) zvol_create_minor_impl(dsname); + minors_job_t *job; + char *n = strdup(dsname); + if (n == NULL) + return (0); + + job = kmem_alloc(sizeof (minors_job_t), KM_SLEEP); + job->name = n; + job->list = minors_list; + job->error = 0; + list_insert_tail(minors_list, job); + /* don't care if dispatch fails, because job->error is 0 */ + taskq_dispatch(system_taskq, zvol_prefetch_minors_impl, job, + TQ_SLEEP); } return (0); @@ -1516,6 +1556,7 @@ zvol_create_minors_cb(const char *dsname, void *arg) { uint64_t snapdev; int error; + list_t *minors_list = arg; ASSERT0(MUTEX_HELD(&spa_namespace_lock)); @@ -1531,19 +1572,28 @@ zvol_create_minors_cb(const char *dsname, void *arg) * snapshots and create device minor nodes for those. */ if (strchr(dsname, '@') == 0) { - /* create minor for the 'dsname' explicitly */ - error = zvol_create_minor_impl(dsname); - if ((error == 0 || error == EEXIST) && - (snapdev == ZFS_SNAPDEV_VISIBLE)) { - fstrans_cookie_t cookie = spl_fstrans_mark(); + minors_job_t *job; + char *n = strdup(dsname); + if (n == NULL) + return (0); + + job = kmem_alloc(sizeof (minors_job_t), KM_SLEEP); + job->name = n; + job->list = minors_list; + job->error = 0; + list_insert_tail(minors_list, job); + /* don't care if dispatch fails, because job->error is 0 */ + taskq_dispatch(system_taskq, zvol_prefetch_minors_impl, job, + TQ_SLEEP); + + if (snapdev == ZFS_SNAPDEV_VISIBLE) { /* * traverse snapshots only, do not traverse children, * and skip the 'dsname' */ error = dmu_objset_find((char *)dsname, - zvol_create_snap_minor_cb, (void *)dsname, + zvol_create_snap_minor_cb, (void *)job, DS_FIND_SNAPSHOTS); - spl_fstrans_unmark(cookie); } } else { dprintf("zvol_create_minors_cb(): %s is not a zvol name\n", @@ -1576,10 +1626,24 @@ zvol_create_minors_impl(const char *name) int error = 0; fstrans_cookie_t cookie; char *atp, *parent; + list_t minors_list; + minors_job_t *job; if (zvol_inhibit_dev) return (0); + /* + * This is the list for prefetch jobs. Whenever we found a match + * during dmu_objset_find, we insert a minors_job to the list and do + * taskq_dispatch to parallel prefetch zvol dnodes. Note we don't need + * any lock because all list operation is done on the current thread. + * + * We will use this list to do zvol_create_minor_impl after prefetch + * so we don't have to traverse using dmu_objset_find again. + */ + list_create(&minors_list, sizeof (minors_job_t), + offsetof(minors_job_t, link)); + parent = kmem_alloc(MAXPATHLEN, KM_SLEEP); (void) strlcpy(parent, name, MAXPATHLEN); @@ -1595,11 +1659,26 @@ zvol_create_minors_impl(const char *name) } else { cookie = spl_fstrans_mark(); error = dmu_objset_find(parent, zvol_create_minors_cb, - NULL, DS_FIND_CHILDREN); + &minors_list, DS_FIND_CHILDREN); spl_fstrans_unmark(cookie); } kmem_free(parent, MAXPATHLEN); + taskq_wait_outstanding(system_taskq, 0); + + /* + * Prefetch is completed, we can do zvol_create_minor_impl + * sequentially. + */ + while ((job = list_head(&minors_list)) != NULL) { + list_remove(&minors_list, job); + if (!job->error) + zvol_create_minor_impl(job->name); + strfree(job->name); + kmem_free(job, sizeof (minors_job_t)); + } + + list_destroy(&minors_list); return (SET_ERROR(error)); } |