diff options
Diffstat (limited to 'sys/contrib/openzfs/module/zfs/vdev_removal.c')
| -rw-r--r-- | sys/contrib/openzfs/module/zfs/vdev_removal.c | 100 |
1 files changed, 68 insertions, 32 deletions
diff --git a/sys/contrib/openzfs/module/zfs/vdev_removal.c b/sys/contrib/openzfs/module/zfs/vdev_removal.c index 2f7a739da241..81e6ecb68ff1 100644 --- a/sys/contrib/openzfs/module/zfs/vdev_removal.c +++ b/sys/contrib/openzfs/module/zfs/vdev_removal.c @@ -51,34 +51,70 @@ #include <sys/trace_zfs.h> /* - * This file contains the necessary logic to remove vdevs from a - * storage pool. Currently, the only devices that can be removed - * are log, cache, and spare devices; and top level vdevs from a pool - * w/o raidz or mirrors. (Note that members of a mirror can be removed - * by the detach operation.) + * This file contains the necessary logic to remove vdevs from a storage + * pool. Note that members of a mirror can be removed by the detach + * operation. Currently, the only devices that can be removed are: * - * Log vdevs are removed by evacuating them and then turning the vdev - * into a hole vdev while holding spa config locks. + * 1) Traditional hot spare and cache vdevs. Note that draid distributed + * spares are fixed at creation time and cannot be removed. * - * Top level vdevs are removed and converted into an indirect vdev via - * a multi-step process: + * 2) Log vdevs are removed by evacuating them and then turning the vdev + * into a hole vdev while holding spa config locks. * - * - Disable allocations from this device (spa_vdev_remove_top). + * 3) Top-level singleton and mirror vdevs, including dedup and special + * vdevs, are removed and converted into an indirect vdev via a + * multi-step process: * - * - From a new thread (spa_vdev_remove_thread), copy data from - * the removing vdev to a different vdev. The copy happens in open - * context (spa_vdev_copy_impl) and issues a sync task - * (vdev_mapping_sync) so the sync thread can update the partial - * indirect mappings in core and on disk. + * - Disable allocations from this device (spa_vdev_remove_top). * - * - If a free happens during a removal, it is freed from the - * removing vdev, and if it has already been copied, from the new - * location as well (free_from_removing_vdev). + * - From a new thread (spa_vdev_remove_thread), copy data from the + * removing vdev to a different vdev. The copy happens in open context + * (spa_vdev_copy_impl) and issues a sync task (vdev_mapping_sync) so + * the sync thread can update the partial indirect mappings in core + * and on disk. * - * - After the removal is completed, the copy thread converts the vdev - * into an indirect vdev (vdev_remove_complete) before instructing - * the sync thread to destroy the space maps and finish the removal - * (spa_finish_removal). + * - If a free happens during a removal, it is freed from the removing + * vdev, and if it has already been copied, from the new location as + * well (free_from_removing_vdev). + * + * - After the removal is completed, the copy thread converts the vdev + * into an indirect vdev (vdev_remove_complete) before instructing + * the sync thread to destroy the space maps and finish the removal + * (spa_finish_removal). + * + * The following constraints currently apply primary device removal: + * + * - All vdevs must be online, healthy, and not be missing any data + * according to the DTLs. + * + * - When removing a singleton or mirror vdev, regardless of it's a + * special, dedup, or primary device, it must have the same ashift + * as the devices in the normal allocation class. Furthermore, all + * vdevs in the normal allocation class must have the same ashift to + * ensure the new allocations never includes additional padding. + * + * - The normal allocation class cannot contain any raidz or draid + * top-level vdevs since segments are copied without regard for block + * boundaries. This makes it impossible to calculate the required + * parity columns when using these vdev types as the destination. + * + * - The encryption keys must be loaded so the ZIL logs can be reset + * in order to prevent writing to the device being removed. + * + * N.B. ashift and raidz/draid constraints for primary top-level device + * removal could be slightly relaxed if it were possible to request that + * DVAs from a mirror or singleton in the specified allocation class be + * used (metaslab_alloc_dva). + * + * This flexibility would be particularly useful for raidz/draid pools which + * often include a mirrored special device. If a mistakenly added top-level + * singleton were added it could then still be removed at the cost of some + * special device capacity. This may be a worthwhile tradeoff depending on + * the pool capacity and expense (cost, complexity, time) of creating a new + * pool and copying all of the data to correct the configuration. + * + * Furthermore, while not currently supported it should be possible to allow + * vdevs of any type to be removed as long as they've never been written to. */ typedef struct vdev_copy_arg { @@ -273,12 +309,12 @@ spa_vdev_noalloc(spa_t *spa, uint64_t guid) uint64_t txg; int error = 0; - ASSERT(!MUTEX_HELD(&spa_namespace_lock)); + ASSERT(!spa_namespace_held()); ASSERT(spa_writeable(spa)); txg = spa_vdev_enter(spa); - ASSERT(MUTEX_HELD(&spa_namespace_lock)); + ASSERT(spa_namespace_held()); vd = spa_lookup_by_guid(spa, guid, B_FALSE); @@ -306,12 +342,12 @@ spa_vdev_alloc(spa_t *spa, uint64_t guid) uint64_t txg; int error = 0; - ASSERT(!MUTEX_HELD(&spa_namespace_lock)); + ASSERT(!spa_namespace_held()); ASSERT(spa_writeable(spa)); txg = spa_vdev_enter(spa); - ASSERT(MUTEX_HELD(&spa_namespace_lock)); + ASSERT(spa_namespace_held()); vd = spa_lookup_by_guid(spa, guid, B_FALSE); @@ -2049,7 +2085,7 @@ vdev_remove_make_hole_and_free(vdev_t *vd) spa_t *spa = vd->vdev_spa; vdev_t *rvd = spa->spa_root_vdev; - ASSERT(MUTEX_HELD(&spa_namespace_lock)); + ASSERT(spa_namespace_held()); ASSERT(spa_config_held(spa, SCL_ALL, RW_WRITER) == SCL_ALL); vdev_free(vd); @@ -2077,7 +2113,7 @@ spa_vdev_remove_log(vdev_t *vd, uint64_t *txg) ASSERT(vd->vdev_islog); ASSERT(vd == vd->vdev_top); ASSERT0P(vd->vdev_log_mg); - ASSERT(MUTEX_HELD(&spa_namespace_lock)); + ASSERT(spa_namespace_held()); /* * Stop allocating from this vdev. @@ -2104,7 +2140,7 @@ spa_vdev_remove_log(vdev_t *vd, uint64_t *txg) * spa_namespace_lock held. Once this completes the device * should no longer have any blocks allocated on it. */ - ASSERT(MUTEX_HELD(&spa_namespace_lock)); + ASSERT(spa_namespace_held()); if (vd->vdev_stat.vs_alloc != 0) error = spa_reset_logs(spa); @@ -2153,7 +2189,7 @@ spa_vdev_remove_log(vdev_t *vd, uint64_t *txg) sysevent_t *ev = spa_event_create(spa, vd, NULL, ESC_ZFS_VDEV_REMOVE_DEV); - ASSERT(MUTEX_HELD(&spa_namespace_lock)); + ASSERT(spa_namespace_held()); ASSERT(spa_config_held(spa, SCL_ALL, RW_WRITER) == SCL_ALL); /* The top ZAP should have been destroyed by vdev_remove_empty. */ @@ -2397,7 +2433,7 @@ spa_vdev_remove(spa_t *spa, uint64_t guid, boolean_t unspare) uint64_t txg = 0; uint_t nspares, nl2cache; int error = 0, error_log; - boolean_t locked = MUTEX_HELD(&spa_namespace_lock); + boolean_t locked = spa_namespace_held(); sysevent_t *ev = NULL; const char *vd_type = NULL; char *vd_path = NULL; @@ -2407,7 +2443,7 @@ spa_vdev_remove(spa_t *spa, uint64_t guid, boolean_t unspare) if (!locked) txg = spa_vdev_enter(spa); - ASSERT(MUTEX_HELD(&spa_namespace_lock)); + ASSERT(spa_namespace_held()); if (spa_feature_is_active(spa, SPA_FEATURE_POOL_CHECKPOINT)) { error = (spa_has_checkpoint(spa)) ? ZFS_ERR_CHECKPOINT_EXISTS : ZFS_ERR_DISCARDING_CHECKPOINT; |