diff options
Diffstat (limited to 'uts/common/fs/zfs/dsl_dataset.c')
| -rw-r--r-- | uts/common/fs/zfs/dsl_dataset.c | 4030 |
1 files changed, 4030 insertions, 0 deletions
diff --git a/uts/common/fs/zfs/dsl_dataset.c b/uts/common/fs/zfs/dsl_dataset.c new file mode 100644 index 000000000000..59ac4a60947a --- /dev/null +++ b/uts/common/fs/zfs/dsl_dataset.c @@ -0,0 +1,4030 @@ +/* + * CDDL HEADER START + * + * The contents of this file are subject to the terms of the + * Common Development and Distribution License (the "License"). + * You may not use this file except in compliance with the License. + * + * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE + * or http://www.opensolaris.org/os/licensing. + * See the License for the specific language governing permissions + * and limitations under the License. + * + * When distributing Covered Code, include this CDDL HEADER in each + * file and include the License file at usr/src/OPENSOLARIS.LICENSE. + * If applicable, add the following below this CDDL HEADER, with the + * fields enclosed by brackets "[]" replaced with your own identifying + * information: Portions Copyright [yyyy] [name of copyright owner] + * + * CDDL HEADER END + */ +/* + * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved. + */ + +#include <sys/dmu_objset.h> +#include <sys/dsl_dataset.h> +#include <sys/dsl_dir.h> +#include <sys/dsl_prop.h> +#include <sys/dsl_synctask.h> +#include <sys/dmu_traverse.h> +#include <sys/dmu_tx.h> +#include <sys/arc.h> +#include <sys/zio.h> +#include <sys/zap.h> +#include <sys/unique.h> +#include <sys/zfs_context.h> +#include <sys/zfs_ioctl.h> +#include <sys/spa.h> +#include <sys/zfs_znode.h> +#include <sys/zfs_onexit.h> +#include <sys/zvol.h> +#include <sys/dsl_scan.h> +#include <sys/dsl_deadlist.h> + +static char *dsl_reaper = "the grim reaper"; + +static dsl_checkfunc_t dsl_dataset_destroy_begin_check; +static dsl_syncfunc_t dsl_dataset_destroy_begin_sync; +static dsl_syncfunc_t dsl_dataset_set_reservation_sync; + +#define SWITCH64(x, y) \ + { \ + uint64_t __tmp = (x); \ + (x) = (y); \ + (y) = __tmp; \ + } + +#define DS_REF_MAX (1ULL << 62) + +#define DSL_DEADLIST_BLOCKSIZE SPA_MAXBLOCKSIZE + +#define DSL_DATASET_IS_DESTROYED(ds) ((ds)->ds_owner == dsl_reaper) + + +/* + * Figure out how much of this delta should be propogated to the dsl_dir + * layer. If there's a refreservation, that space has already been + * partially accounted for in our ancestors. + */ +static int64_t +parent_delta(dsl_dataset_t *ds, int64_t delta) +{ + uint64_t old_bytes, new_bytes; + + if (ds->ds_reserved == 0) + return (delta); + + old_bytes = MAX(ds->ds_phys->ds_unique_bytes, ds->ds_reserved); + new_bytes = MAX(ds->ds_phys->ds_unique_bytes + delta, ds->ds_reserved); + + ASSERT3U(ABS((int64_t)(new_bytes - old_bytes)), <=, ABS(delta)); + return (new_bytes - old_bytes); +} + +void +dsl_dataset_block_born(dsl_dataset_t *ds, const blkptr_t *bp, dmu_tx_t *tx) +{ + int used = bp_get_dsize_sync(tx->tx_pool->dp_spa, bp); + int compressed = BP_GET_PSIZE(bp); + int uncompressed = BP_GET_UCSIZE(bp); + int64_t delta; + + dprintf_bp(bp, "ds=%p", ds); + + ASSERT(dmu_tx_is_syncing(tx)); + /* It could have been compressed away to nothing */ + if (BP_IS_HOLE(bp)) + return; + ASSERT(BP_GET_TYPE(bp) != DMU_OT_NONE); + ASSERT3U(BP_GET_TYPE(bp), <, DMU_OT_NUMTYPES); + if (ds == NULL) { + /* + * Account for the meta-objset space in its placeholder + * dsl_dir. + */ + ASSERT3U(compressed, ==, uncompressed); /* it's all metadata */ + dsl_dir_diduse_space(tx->tx_pool->dp_mos_dir, DD_USED_HEAD, + used, compressed, uncompressed, tx); + dsl_dir_dirty(tx->tx_pool->dp_mos_dir, tx); + return; + } + dmu_buf_will_dirty(ds->ds_dbuf, tx); + + mutex_enter(&ds->ds_dir->dd_lock); + mutex_enter(&ds->ds_lock); + delta = parent_delta(ds, used); + ds->ds_phys->ds_used_bytes += used; + ds->ds_phys->ds_compressed_bytes += compressed; + ds->ds_phys->ds_uncompressed_bytes += uncompressed; + ds->ds_phys->ds_unique_bytes += used; + mutex_exit(&ds->ds_lock); + dsl_dir_diduse_space(ds->ds_dir, DD_USED_HEAD, delta, + compressed, uncompressed, tx); + dsl_dir_transfer_space(ds->ds_dir, used - delta, + DD_USED_REFRSRV, DD_USED_HEAD, tx); + mutex_exit(&ds->ds_dir->dd_lock); +} + +int +dsl_dataset_block_kill(dsl_dataset_t *ds, const blkptr_t *bp, dmu_tx_t *tx, + boolean_t async) +{ + if (BP_IS_HOLE(bp)) + return (0); + + ASSERT(dmu_tx_is_syncing(tx)); + ASSERT(bp->blk_birth <= tx->tx_txg); + + int used = bp_get_dsize_sync(tx->tx_pool->dp_spa, bp); + int compressed = BP_GET_PSIZE(bp); + int uncompressed = BP_GET_UCSIZE(bp); + + ASSERT(used > 0); + if (ds == NULL) { + /* + * Account for the meta-objset space in its placeholder + * dataset. + */ + dsl_free(tx->tx_pool, tx->tx_txg, bp); + + dsl_dir_diduse_space(tx->tx_pool->dp_mos_dir, DD_USED_HEAD, + -used, -compressed, -uncompressed, tx); + dsl_dir_dirty(tx->tx_pool->dp_mos_dir, tx); + return (used); + } + ASSERT3P(tx->tx_pool, ==, ds->ds_dir->dd_pool); + + ASSERT(!dsl_dataset_is_snapshot(ds)); + dmu_buf_will_dirty(ds->ds_dbuf, tx); + + if (bp->blk_birth > ds->ds_phys->ds_prev_snap_txg) { + int64_t delta; + + dprintf_bp(bp, "freeing ds=%llu", ds->ds_object); + dsl_free(tx->tx_pool, tx->tx_txg, bp); + + mutex_enter(&ds->ds_dir->dd_lock); + mutex_enter(&ds->ds_lock); + ASSERT(ds->ds_phys->ds_unique_bytes >= used || + !DS_UNIQUE_IS_ACCURATE(ds)); + delta = parent_delta(ds, -used); + ds->ds_phys->ds_unique_bytes -= used; + mutex_exit(&ds->ds_lock); + dsl_dir_diduse_space(ds->ds_dir, DD_USED_HEAD, + delta, -compressed, -uncompressed, tx); + dsl_dir_transfer_space(ds->ds_dir, -used - delta, + DD_USED_REFRSRV, DD_USED_HEAD, tx); + mutex_exit(&ds->ds_dir->dd_lock); + } else { + dprintf_bp(bp, "putting on dead list: %s", ""); + if (async) { + /* + * We are here as part of zio's write done callback, + * which means we're a zio interrupt thread. We can't + * call dsl_deadlist_insert() now because it may block + * waiting for I/O. Instead, put bp on the deferred + * queue and let dsl_pool_sync() finish the job. + */ + bplist_append(&ds->ds_pending_deadlist, bp); + } else { + dsl_deadlist_insert(&ds->ds_deadlist, bp, tx); + } + ASSERT3U(ds->ds_prev->ds_object, ==, + ds->ds_phys->ds_prev_snap_obj); + ASSERT(ds->ds_prev->ds_phys->ds_num_children > 0); + /* if (bp->blk_birth > prev prev snap txg) prev unique += bs */ + if (ds->ds_prev->ds_phys->ds_next_snap_obj == + ds->ds_object && bp->blk_birth > + ds->ds_prev->ds_phys->ds_prev_snap_txg) { + dmu_buf_will_dirty(ds->ds_prev->ds_dbuf, tx); + mutex_enter(&ds->ds_prev->ds_lock); + ds->ds_prev->ds_phys->ds_unique_bytes += used; + mutex_exit(&ds->ds_prev->ds_lock); + } + if (bp->blk_birth > ds->ds_dir->dd_origin_txg) { + dsl_dir_transfer_space(ds->ds_dir, used, + DD_USED_HEAD, DD_USED_SNAP, tx); + } + } + mutex_enter(&ds->ds_lock); + ASSERT3U(ds->ds_phys->ds_used_bytes, >=, used); + ds->ds_phys->ds_used_bytes -= used; + ASSERT3U(ds->ds_phys->ds_compressed_bytes, >=, compressed); + ds->ds_phys->ds_compressed_bytes -= compressed; + ASSERT3U(ds->ds_phys->ds_uncompressed_bytes, >=, uncompressed); + ds->ds_phys->ds_uncompressed_bytes -= uncompressed; + mutex_exit(&ds->ds_lock); + + return (used); +} + +uint64_t +dsl_dataset_prev_snap_txg(dsl_dataset_t *ds) +{ + uint64_t trysnap = 0; + + if (ds == NULL) + return (0); + /* + * The snapshot creation could fail, but that would cause an + * incorrect FALSE return, which would only result in an + * overestimation of the amount of space that an operation would + * consume, which is OK. + * + * There's also a small window where we could miss a pending + * snapshot, because we could set the sync task in the quiescing + * phase. So this should only be used as a guess. + */ + if (ds->ds_trysnap_txg > + spa_last_synced_txg(ds->ds_dir->dd_pool->dp_spa)) + trysnap = ds->ds_trysnap_txg; + return (MAX(ds->ds_phys->ds_prev_snap_txg, trysnap)); +} + +boolean_t +dsl_dataset_block_freeable(dsl_dataset_t *ds, const blkptr_t *bp, + uint64_t blk_birth) +{ + if (blk_birth <= dsl_dataset_prev_snap_txg(ds)) + return (B_FALSE); + + ddt_prefetch(dsl_dataset_get_spa(ds), bp); + + return (B_TRUE); +} + +/* ARGSUSED */ +static void +dsl_dataset_evict(dmu_buf_t *db, void *dsv) +{ + dsl_dataset_t *ds = dsv; + + ASSERT(ds->ds_owner == NULL || DSL_DATASET_IS_DESTROYED(ds)); + + unique_remove(ds->ds_fsid_guid); + + if (ds->ds_objset != NULL) + dmu_objset_evict(ds->ds_objset); + + if (ds->ds_prev) { + dsl_dataset_drop_ref(ds->ds_prev, ds); + ds->ds_prev = NULL; + } + + bplist_destroy(&ds->ds_pending_deadlist); + if (db != NULL) { + dsl_deadlist_close(&ds->ds_deadlist); + } else { + ASSERT(ds->ds_deadlist.dl_dbuf == NULL); + ASSERT(!ds->ds_deadlist.dl_oldfmt); + } + if (ds->ds_dir) + dsl_dir_close(ds->ds_dir, ds); + + ASSERT(!list_link_active(&ds->ds_synced_link)); + + mutex_destroy(&ds->ds_lock); + mutex_destroy(&ds->ds_recvlock); + mutex_destroy(&ds->ds_opening_lock); + rw_destroy(&ds->ds_rwlock); + cv_destroy(&ds->ds_exclusive_cv); + + kmem_free(ds, sizeof (dsl_dataset_t)); +} + +static int +dsl_dataset_get_snapname(dsl_dataset_t *ds) +{ + dsl_dataset_phys_t *headphys; + int err; + dmu_buf_t *headdbuf; + dsl_pool_t *dp = ds->ds_dir->dd_pool; + objset_t *mos = dp->dp_meta_objset; + + if (ds->ds_snapname[0]) + return (0); + if (ds->ds_phys->ds_next_snap_obj == 0) + return (0); + + err = dmu_bonus_hold(mos, ds->ds_dir->dd_phys->dd_head_dataset_obj, + FTAG, &headdbuf); + if (err) + return (err); + headphys = headdbuf->db_data; + err = zap_value_search(dp->dp_meta_objset, + headphys->ds_snapnames_zapobj, ds->ds_object, 0, ds->ds_snapname); + dmu_buf_rele(headdbuf, FTAG); + return (err); +} + +static int +dsl_dataset_snap_lookup(dsl_dataset_t *ds, const char *name, uint64_t *value) +{ + objset_t *mos = ds->ds_dir->dd_pool->dp_meta_objset; + uint64_t snapobj = ds->ds_phys->ds_snapnames_zapobj; + matchtype_t mt; + int err; + + if (ds->ds_phys->ds_flags & DS_FLAG_CI_DATASET) + mt = MT_FIRST; + else + mt = MT_EXACT; + + err = zap_lookup_norm(mos, snapobj, name, 8, 1, + value, mt, NULL, 0, NULL); + if (err == ENOTSUP && mt == MT_FIRST) + err = zap_lookup(mos, snapobj, name, 8, 1, value); + return (err); +} + +static int +dsl_dataset_snap_remove(dsl_dataset_t *ds, char *name, dmu_tx_t *tx) +{ + objset_t *mos = ds->ds_dir->dd_pool->dp_meta_objset; + uint64_t snapobj = ds->ds_phys->ds_snapnames_zapobj; + matchtype_t mt; + int err; + + dsl_dir_snap_cmtime_update(ds->ds_dir); + + if (ds->ds_phys->ds_flags & DS_FLAG_CI_DATASET) + mt = MT_FIRST; + else + mt = MT_EXACT; + + err = zap_remove_norm(mos, snapobj, name, mt, tx); + if (err == ENOTSUP && mt == MT_FIRST) + err = zap_remove(mos, snapobj, name, tx); + return (err); +} + +static int +dsl_dataset_get_ref(dsl_pool_t *dp, uint64_t dsobj, void *tag, + dsl_dataset_t **dsp) +{ + objset_t *mos = dp->dp_meta_objset; + dmu_buf_t *dbuf; + dsl_dataset_t *ds; + int err; + dmu_object_info_t doi; + + ASSERT(RW_LOCK_HELD(&dp->dp_config_rwlock) || + dsl_pool_sync_context(dp)); + + err = dmu_bonus_hold(mos, dsobj, tag, &dbuf); + if (err) + return (err); + + /* Make sure dsobj has the correct object type. */ + dmu_object_info_from_db(dbuf, &doi); + if (doi.doi_type != DMU_OT_DSL_DATASET) + return (EINVAL); + + ds = dmu_buf_get_user(dbuf); + if (ds == NULL) { + dsl_dataset_t *winner; + + ds = kmem_zalloc(sizeof (dsl_dataset_t), KM_SLEEP); + ds->ds_dbuf = dbuf; + ds->ds_object = dsobj; + ds->ds_phys = dbuf->db_data; + + mutex_init(&ds->ds_lock, NULL, MUTEX_DEFAULT, NULL); + mutex_init(&ds->ds_recvlock, NULL, MUTEX_DEFAULT, NULL); + mutex_init(&ds->ds_opening_lock, NULL, MUTEX_DEFAULT, NULL); + rw_init(&ds->ds_rwlock, 0, 0, 0); + cv_init(&ds->ds_exclusive_cv, NULL, CV_DEFAULT, NULL); + + bplist_create(&ds->ds_pending_deadlist); + dsl_deadlist_open(&ds->ds_deadlist, + mos, ds->ds_phys->ds_deadlist_obj); + + if (err == 0) { + err = dsl_dir_open_obj(dp, + ds->ds_phys->ds_dir_obj, NULL, ds, &ds->ds_dir); + } + if (err) { + mutex_destroy(&ds->ds_lock); + mutex_destroy(&ds->ds_recvlock); + mutex_destroy(&ds->ds_opening_lock); + rw_destroy(&ds->ds_rwlock); + cv_destroy(&ds->ds_exclusive_cv); + bplist_destroy(&ds->ds_pending_deadlist); + dsl_deadlist_close(&ds->ds_deadlist); + kmem_free(ds, sizeof (dsl_dataset_t)); + dmu_buf_rele(dbuf, tag); + return (err); + } + + if (!dsl_dataset_is_snapshot(ds)) { + ds->ds_snapname[0] = '\0'; + if (ds->ds_phys->ds_prev_snap_obj) { + err = dsl_dataset_get_ref(dp, + ds->ds_phys->ds_prev_snap_obj, + ds, &ds->ds_prev); + } + } else { + if (zfs_flags & ZFS_DEBUG_SNAPNAMES) + err = dsl_dataset_get_snapname(ds); + if (err == 0 && ds->ds_phys->ds_userrefs_obj != 0) { + err = zap_count( + ds->ds_dir->dd_pool->dp_meta_objset, + ds->ds_phys->ds_userrefs_obj, + &ds->ds_userrefs); + } + } + + if (err == 0 && !dsl_dataset_is_snapshot(ds)) { + /* + * In sync context, we're called with either no lock + * or with the write lock. If we're not syncing, + * we're always called with the read lock held. + */ + boolean_t need_lock = + !RW_WRITE_HELD(&dp->dp_config_rwlock) && + dsl_pool_sync_context(dp); + + if (need_lock) + rw_enter(&dp->dp_config_rwlock, RW_READER); + + err = dsl_prop_get_ds(ds, + "refreservation", sizeof (uint64_t), 1, + &ds->ds_reserved, NULL); + if (err == 0) { + err = dsl_prop_get_ds(ds, + "refquota", sizeof (uint64_t), 1, + &ds->ds_quota, NULL); + } + + if (need_lock) + rw_exit(&dp->dp_config_rwlock); + } else { + ds->ds_reserved = ds->ds_quota = 0; + } + + if (err == 0) { + winner = dmu_buf_set_user_ie(dbuf, ds, &ds->ds_phys, + dsl_dataset_evict); + } + if (err || winner) { + bplist_destroy(&ds->ds_pending_deadlist); + dsl_deadlist_close(&ds->ds_deadlist); + if (ds->ds_prev) + dsl_dataset_drop_ref(ds->ds_prev, ds); + dsl_dir_close(ds->ds_dir, ds); + mutex_destroy(&ds->ds_lock); + mutex_destroy(&ds->ds_recvlock); + mutex_destroy(&ds->ds_opening_lock); + rw_destroy(&ds->ds_rwlock); + cv_destroy(&ds->ds_exclusive_cv); + kmem_free(ds, sizeof (dsl_dataset_t)); + if (err) { + dmu_buf_rele(dbuf, tag); + return (err); + } + ds = winner; + } else { + ds->ds_fsid_guid = + unique_insert(ds->ds_phys->ds_fsid_guid); + } + } + ASSERT3P(ds->ds_dbuf, ==, dbuf); + ASSERT3P(ds->ds_phys, ==, dbuf->db_data); + ASSERT(ds->ds_phys->ds_prev_snap_obj != 0 || + spa_version(dp->dp_spa) < SPA_VERSION_ORIGIN || + dp->dp_origin_snap == NULL || ds == dp->dp_origin_snap); + mutex_enter(&ds->ds_lock); + if (!dsl_pool_sync_context(dp) && DSL_DATASET_IS_DESTROYED(ds)) { + mutex_exit(&ds->ds_lock); + dmu_buf_rele(ds->ds_dbuf, tag); + return (ENOENT); + } + mutex_exit(&ds->ds_lock); + *dsp = ds; + return (0); +} + +static int +dsl_dataset_hold_ref(dsl_dataset_t *ds, void *tag) +{ + dsl_pool_t *dp = ds->ds_dir->dd_pool; + + /* + * In syncing context we don't want the rwlock lock: there + * may be an existing writer waiting for sync phase to + * finish. We don't need to worry about such writers, since + * sync phase is single-threaded, so the writer can't be + * doing anything while we are active. + */ + if (dsl_pool_sync_context(dp)) { + ASSERT(!DSL_DATASET_IS_DESTROYED(ds)); + return (0); + } + + /* + * Normal users will hold the ds_rwlock as a READER until they + * are finished (i.e., call dsl_dataset_rele()). "Owners" will + * drop their READER lock after they set the ds_owner field. + * + * If the dataset is being destroyed, the destroy thread will + * obtain a WRITER lock for exclusive access after it's done its + * open-context work and then change the ds_owner to + * dsl_reaper once destruction is assured. So threads + * may block here temporarily, until the "destructability" of + * the dataset is determined. + */ + ASSERT(!RW_WRITE_HELD(&dp->dp_config_rwlock)); + mutex_enter(&ds->ds_lock); + while (!rw_tryenter(&ds->ds_rwlock, RW_READER)) { + rw_exit(&dp->dp_config_rwlock); + cv_wait(&ds->ds_exclusive_cv, &ds->ds_lock); + if (DSL_DATASET_IS_DESTROYED(ds)) { + mutex_exit(&ds->ds_lock); + dsl_dataset_drop_ref(ds, tag); + rw_enter(&dp->dp_config_rwlock, RW_READER); + return (ENOENT); + } + /* + * The dp_config_rwlock lives above the ds_lock. And + * we need to check DSL_DATASET_IS_DESTROYED() while + * holding the ds_lock, so we have to drop and reacquire + * the ds_lock here. + */ + mutex_exit(&ds->ds_lock); + rw_enter(&dp->dp_config_rwlock, RW_READER); + mutex_enter(&ds->ds_lock); + } + mutex_exit(&ds->ds_lock); + return (0); +} + +int +dsl_dataset_hold_obj(dsl_pool_t *dp, uint64_t dsobj, void *tag, + dsl_dataset_t **dsp) +{ + int err = dsl_dataset_get_ref(dp, dsobj, tag, dsp); + + if (err) + return (err); + return (dsl_dataset_hold_ref(*dsp, tag)); +} + +int +dsl_dataset_own_obj(dsl_pool_t *dp, uint64_t dsobj, boolean_t inconsistentok, + void *tag, dsl_dataset_t **dsp) +{ + int err = dsl_dataset_hold_obj(dp, dsobj, tag, dsp); + if (err) + return (err); + if (!dsl_dataset_tryown(*dsp, inconsistentok, tag)) { + dsl_dataset_rele(*dsp, tag); + *dsp = NULL; + return (EBUSY); + } + return (0); +} + +int +dsl_dataset_hold(const char *name, void *tag, dsl_dataset_t **dsp) +{ + dsl_dir_t *dd; + dsl_pool_t *dp; + const char *snapname; + uint64_t obj; + int err = 0; + + err = dsl_dir_open_spa(NULL, name, FTAG, &dd, &snapname); + if (err) + return (err); + + dp = dd->dd_pool; + obj = dd->dd_phys->dd_head_dataset_obj; + rw_enter(&dp->dp_config_rwlock, RW_READER); + if (obj) + err = dsl_dataset_get_ref(dp, obj, tag, dsp); + else + err = ENOENT; + if (err) + goto out; + + err = dsl_dataset_hold_ref(*dsp, tag); + + /* we may be looking for a snapshot */ + if (err == 0 && snapname != NULL) { + dsl_dataset_t *ds = NULL; + + if (*snapname++ != '@') { + dsl_dataset_rele(*dsp, tag); + err = ENOENT; + goto out; + } + + dprintf("looking for snapshot '%s'\n", snapname); + err = dsl_dataset_snap_lookup(*dsp, snapname, &obj); + if (err == 0) + err = dsl_dataset_get_ref(dp, obj, tag, &ds); + dsl_dataset_rele(*dsp, tag); + + ASSERT3U((err == 0), ==, (ds != NULL)); + + if (ds) { + mutex_enter(&ds->ds_lock); + if (ds->ds_snapname[0] == 0) + (void) strlcpy(ds->ds_snapname, snapname, + sizeof (ds->ds_snapname)); + mutex_exit(&ds->ds_lock); + err = dsl_dataset_hold_ref(ds, tag); + *dsp = err ? NULL : ds; + } + } +out: + rw_exit(&dp->dp_config_rwlock); + dsl_dir_close(dd, FTAG); + return (err); +} + +int +dsl_dataset_own(const char *name, boolean_t inconsistentok, + void *tag, dsl_dataset_t **dsp) +{ + int err = dsl_dataset_hold(name, tag, dsp); + if (err) + return (err); + if (!dsl_dataset_tryown(*dsp, inconsistentok, tag)) { + dsl_dataset_rele(*dsp, tag); + return (EBUSY); + } + return (0); +} + +void +dsl_dataset_name(dsl_dataset_t *ds, char *name) +{ + if (ds == NULL) { + (void) strcpy(name, "mos"); + } else { + dsl_dir_name(ds->ds_dir, name); + VERIFY(0 == dsl_dataset_get_snapname(ds)); + if (ds->ds_snapname[0]) { + (void) strcat(name, "@"); + /* + * We use a "recursive" mutex so that we + * can call dprintf_ds() with ds_lock held. + */ + if (!MUTEX_HELD(&ds->ds_lock)) { + mutex_enter(&ds->ds_lock); + (void) strcat(name, ds->ds_snapname); + mutex_exit(&ds->ds_lock); + } else { + (void) strcat(name, ds->ds_snapname); + } + } + } +} + +static int +dsl_dataset_namelen(dsl_dataset_t *ds) +{ + int result; + + if (ds == NULL) { + result = 3; /* "mos" */ + } else { + result = dsl_dir_namelen(ds->ds_dir); + VERIFY(0 == dsl_dataset_get_snapname(ds)); + if (ds->ds_snapname[0]) { + ++result; /* adding one for the @-sign */ + if (!MUTEX_HELD(&ds->ds_lock)) { + mutex_enter(&ds->ds_lock); + result += strlen(ds->ds_snapname); + mutex_exit(&ds->ds_lock); + } else { + result += strlen(ds->ds_snapname); + } + } + } + + return (result); +} + +void +dsl_dataset_drop_ref(dsl_dataset_t *ds, void *tag) +{ + dmu_buf_rele(ds->ds_dbuf, tag); +} + +void +dsl_dataset_rele(dsl_dataset_t *ds, void *tag) +{ + if (!dsl_pool_sync_context(ds->ds_dir->dd_pool)) { + rw_exit(&ds->ds_rwlock); + } + dsl_dataset_drop_ref(ds, tag); +} + +void +dsl_dataset_disown(dsl_dataset_t *ds, void *tag) +{ + ASSERT((ds->ds_owner == tag && ds->ds_dbuf) || + (DSL_DATASET_IS_DESTROYED(ds) && ds->ds_dbuf == NULL)); + + mutex_enter(&ds->ds_lock); + ds->ds_owner = NULL; + if (RW_WRITE_HELD(&ds->ds_rwlock)) { + rw_exit(&ds->ds_rwlock); + cv_broadcast(&ds->ds_exclusive_cv); + } + mutex_exit(&ds->ds_lock); + if (ds->ds_dbuf) + dsl_dataset_drop_ref(ds, tag); + else + dsl_dataset_evict(NULL, ds); +} + +boolean_t +dsl_dataset_tryown(dsl_dataset_t *ds, boolean_t inconsistentok, void *tag) +{ + boolean_t gotit = FALSE; + + mutex_enter(&ds->ds_lock); + if (ds->ds_owner == NULL && + (!DS_IS_INCONSISTENT(ds) || inconsistentok)) { + ds->ds_owner = tag; + if (!dsl_pool_sync_context(ds->ds_dir->dd_pool)) + rw_exit(&ds->ds_rwlock); + gotit = TRUE; + } + mutex_exit(&ds->ds_lock); + return (gotit); +} + +void +dsl_dataset_make_exclusive(dsl_dataset_t *ds, void *owner) +{ + ASSERT3P(owner, ==, ds->ds_owner); + if (!RW_WRITE_HELD(&ds->ds_rwlock)) + rw_enter(&ds->ds_rwlock, RW_WRITER); +} + +uint64_t +dsl_dataset_create_sync_dd(dsl_dir_t *dd, dsl_dataset_t *origin, + uint64_t flags, dmu_tx_t *tx) +{ + dsl_pool_t *dp = dd->dd_pool; + dmu_buf_t *dbuf; + dsl_dataset_phys_t *dsphys; + uint64_t dsobj; + objset_t *mos = dp->dp_meta_objset; + + if (origin == NULL) + origin = dp->dp_origin_snap; + + ASSERT(origin == NULL || origin->ds_dir->dd_pool == dp); + ASSERT(origin == NULL || origin->ds_phys->ds_num_children > 0); + ASSERT(dmu_tx_is_syncing(tx)); + ASSERT(dd->dd_phys->dd_head_dataset_obj == 0); + + dsobj = dmu_object_alloc(mos, DMU_OT_DSL_DATASET, 0, + DMU_OT_DSL_DATASET, sizeof (dsl_dataset_phys_t), tx); + VERIFY(0 == dmu_bonus_hold(mos, dsobj, FTAG, &dbuf)); + dmu_buf_will_dirty(dbuf, tx); + dsphys = dbuf->db_data; + bzero(dsphys, sizeof (dsl_dataset_phys_t)); + dsphys->ds_dir_obj = dd->dd_object; + dsphys->ds_flags = flags; + dsphys->ds_fsid_guid = unique_create(); + (void) random_get_pseudo_bytes((void*)&dsphys->ds_guid, + sizeof (dsphys->ds_guid)); + dsphys->ds_snapnames_zapobj = + zap_create_norm(mos, U8_TEXTPREP_TOUPPER, DMU_OT_DSL_DS_SNAP_MAP, + DMU_OT_NONE, 0, tx); + dsphys->ds_creation_time = gethrestime_sec(); + dsphys->ds_creation_txg = tx->tx_txg == TXG_INITIAL ? 1 : tx->tx_txg; + + if (origin == NULL) { + dsphys->ds_deadlist_obj = dsl_deadlist_alloc(mos, tx); + } else { + dsl_dataset_t *ohds; + + dsphys->ds_prev_snap_obj = origin->ds_object; + dsphys->ds_prev_snap_txg = + origin->ds_phys->ds_creation_txg; + dsphys->ds_used_bytes = + origin->ds_phys->ds_used_bytes; + dsphys->ds_compressed_bytes = + origin->ds_phys->ds_compressed_bytes; + dsphys->ds_uncompressed_bytes = + origin->ds_phys->ds_uncompressed_bytes; + dsphys->ds_bp = origin->ds_phys->ds_bp; + dsphys->ds_flags |= origin->ds_phys->ds_flags; + + dmu_buf_will_dirty(origin->ds_dbuf, tx); + origin->ds_phys->ds_num_children++; + + VERIFY3U(0, ==, dsl_dataset_hold_obj(dp, + origin->ds_dir->dd_phys->dd_head_dataset_obj, FTAG, &ohds)); + dsphys->ds_deadlist_obj = dsl_deadlist_clone(&ohds->ds_deadlist, + dsphys->ds_prev_snap_txg, dsphys->ds_prev_snap_obj, tx); + dsl_dataset_rele(ohds, FTAG); + + if (spa_version(dp->dp_spa) >= SPA_VERSION_NEXT_CLONES) { + if (origin->ds_phys->ds_next_clones_obj == 0) { + origin->ds_phys->ds_next_clones_obj = + zap_create(mos, + DMU_OT_NEXT_CLONES, DMU_OT_NONE, 0, tx); + } + VERIFY(0 == zap_add_int(mos, + origin->ds_phys->ds_next_clones_obj, + dsobj, tx)); + } + + dmu_buf_will_dirty(dd->dd_dbuf, tx); + dd->dd_phys->dd_origin_obj = origin->ds_object; + if (spa_version(dp->dp_spa) >= SPA_VERSION_DIR_CLONES) { + if (origin->ds_dir->dd_phys->dd_clones == 0) { + dmu_buf_will_dirty(origin->ds_dir->dd_dbuf, tx); + origin->ds_dir->dd_phys->dd_clones = + zap_create(mos, + DMU_OT_DSL_CLONES, DMU_OT_NONE, 0, tx); + } + VERIFY3U(0, ==, zap_add_int(mos, + origin->ds_dir->dd_phys->dd_clones, dsobj, tx)); + } + } + + if (spa_version(dp->dp_spa) >= SPA_VERSION_UNIQUE_ACCURATE) + dsphys->ds_flags |= DS_FLAG_UNIQUE_ACCURATE; + + dmu_buf_rele(dbuf, FTAG); + + dmu_buf_will_dirty(dd->dd_dbuf, tx); + dd->dd_phys->dd_head_dataset_obj = dsobj; + + return (dsobj); +} + +uint64_t +dsl_dataset_create_sync(dsl_dir_t *pdd, const char *lastname, + dsl_dataset_t *origin, uint64_t flags, cred_t *cr, dmu_tx_t *tx) +{ + dsl_pool_t *dp = pdd->dd_pool; + uint64_t dsobj, ddobj; + dsl_dir_t *dd; + + ASSERT(lastname[0] != '@'); + + ddobj = dsl_dir_create_sync(dp, pdd, lastname, tx); + VERIFY(0 == dsl_dir_open_obj(dp, ddobj, lastname, FTAG, &dd)); + + dsobj = dsl_dataset_create_sync_dd(dd, origin, flags, tx); + + dsl_deleg_set_create_perms(dd, tx, cr); + + dsl_dir_close(dd, FTAG); + + /* + * If we are creating a clone, make sure we zero out any stale + * data from the origin snapshots zil header. + */ + if (origin != NULL) { + dsl_dataset_t *ds; + objset_t *os; + + VERIFY3U(0, ==, dsl_dataset_hold_obj(dp, dsobj, FTAG, &ds)); + VERIFY3U(0, ==, dmu_objset_from_ds(ds, &os)); + bzero(&os->os_zil_header, sizeof (os->os_zil_header)); + dsl_dataset_dirty(ds, tx); + dsl_dataset_rele(ds, FTAG); + } + + return (dsobj); +} + +struct destroyarg { + dsl_sync_task_group_t *dstg; + char *snapname; + char *failed; + boolean_t defer; +}; + +static int +dsl_snapshot_destroy_one(const char *name, void *arg) +{ + struct destroyarg *da = arg; + dsl_dataset_t *ds; + int err; + char *dsname; + + dsname = kmem_asprintf("%s@%s", name, da->snapname); + err = dsl_dataset_own(dsname, B_TRUE, da->dstg, &ds); + strfree(dsname); + if (err == 0) { + struct dsl_ds_destroyarg *dsda; + + dsl_dataset_make_exclusive(ds, da->dstg); + dsda = kmem_zalloc(sizeof (struct dsl_ds_destroyarg), KM_SLEEP); + dsda->ds = ds; + dsda->defer = da->defer; + dsl_sync_task_create(da->dstg, dsl_dataset_destroy_check, + dsl_dataset_destroy_sync, dsda, da->dstg, 0); + } else if (err == ENOENT) { + err = 0; + } else { + (void) strcpy(da->failed, name); + } + return (err); +} + +/* + * Destroy 'snapname' in all descendants of 'fsname'. + */ +#pragma weak dmu_snapshots_destroy = dsl_snapshots_destroy +int +dsl_snapshots_destroy(char *fsname, char *snapname, boolean_t defer) +{ + int err; + struct destroyarg da; + dsl_sync_task_t *dst; + spa_t *spa; + + err = spa_open(fsname, &spa, FTAG); + if (err) + return (err); + da.dstg = dsl_sync_task_group_create(spa_get_dsl(spa)); + da.snapname = snapname; + da.failed = fsname; + da.defer = defer; + + err = dmu_objset_find(fsname, + dsl_snapshot_destroy_one, &da, DS_FIND_CHILDREN); + + if (err == 0) + err = dsl_sync_task_group_wait(da.dstg); + + for (dst = list_head(&da.dstg->dstg_tasks); dst; + dst = list_next(&da.dstg->dstg_tasks, dst)) { + struct dsl_ds_destroyarg *dsda = dst->dst_arg1; + dsl_dataset_t *ds = dsda->ds; + + /* + * Return the file system name that triggered the error + */ + if (dst->dst_err) { + dsl_dataset_name(ds, fsname); + *strchr(fsname, '@') = '\0'; + } + ASSERT3P(dsda->rm_origin, ==, NULL); + dsl_dataset_disown(ds, da.dstg); + kmem_free(dsda, sizeof (struct dsl_ds_destroyarg)); + } + + dsl_sync_task_group_destroy(da.dstg); + spa_close(spa, FTAG); + return (err); +} + +static boolean_t +dsl_dataset_might_destroy_origin(dsl_dataset_t *ds) +{ + boolean_t might_destroy = B_FALSE; + + mutex_enter(&ds->ds_lock); + if (ds->ds_phys->ds_num_children == 2 && ds->ds_userrefs == 0 && + DS_IS_DEFER_DESTROY(ds)) + might_destroy = B_TRUE; + mutex_exit(&ds->ds_lock); + + return (might_destroy); +} + +/* + * If we're removing a clone, and these three conditions are true: + * 1) the clone's origin has no other children + * 2) the clone's origin has no user references + * 3) the clone's origin has been marked for deferred destruction + * Then, prepare to remove the origin as part of this sync task group. + */ +static int +dsl_dataset_origin_rm_prep(struct dsl_ds_destroyarg *dsda, void *tag) +{ + dsl_dataset_t *ds = dsda->ds; + dsl_dataset_t *origin = ds->ds_prev; + + if (dsl_dataset_might_destroy_origin(origin)) { + char *name; + int namelen; + int error; + + namelen = dsl_dataset_namelen(origin) + 1; + name = kmem_alloc(namelen, KM_SLEEP); + dsl_dataset_name(origin, name); +#ifdef _KERNEL + error = zfs_unmount_snap(name, NULL); + if (error) { + kmem_free(name, namelen); + return (error); + } +#endif + error = dsl_dataset_own(name, B_TRUE, tag, &origin); + kmem_free(name, namelen); + if (error) + return (error); + dsda->rm_origin = origin; + dsl_dataset_make_exclusive(origin, tag); + } + + return (0); +} + +/* + * ds must be opened as OWNER. On return (whether successful or not), + * ds will be closed and caller can no longer dereference it. + */ +int +dsl_dataset_destroy(dsl_dataset_t *ds, void *tag, boolean_t defer) +{ + int err; + dsl_sync_task_group_t *dstg; + objset_t *os; + dsl_dir_t *dd; + uint64_t obj; + struct dsl_ds_destroyarg dsda = { 0 }; + dsl_dataset_t dummy_ds = { 0 }; + + dsda.ds = ds; + + if (dsl_dataset_is_snapshot(ds)) { + /* Destroying a snapshot is simpler */ + dsl_dataset_make_exclusive(ds, tag); + + dsda.defer = defer; + err = dsl_sync_task_do(ds->ds_dir->dd_pool, + dsl_dataset_destroy_check, dsl_dataset_destroy_sync, + &dsda, tag, 0); + ASSERT3P(dsda.rm_origin, ==, NULL); + goto out; + } else if (defer) { + err = EINVAL; + goto out; + } + + dd = ds->ds_dir; + dummy_ds.ds_dir = dd; + dummy_ds.ds_object = ds->ds_object; + + /* + * Check for errors and mark this ds as inconsistent, in + * case we crash while freeing the objects. + */ + err = dsl_sync_task_do(dd->dd_pool, dsl_dataset_destroy_begin_check, + dsl_dataset_destroy_begin_sync, ds, NULL, 0); + if (err) + goto out; + + err = dmu_objset_from_ds(ds, &os); + if (err) + goto out; + + /* + * remove the objects in open context, so that we won't + * have too much to do in syncing context. + */ + for (obj = 0; err == 0; err = dmu_object_next(os, &obj, FALSE, + ds->ds_phys->ds_prev_snap_txg)) { + /* + * Ignore errors, if there is not enough disk space + * we will deal with it in dsl_dataset_destroy_sync(). + */ + (void) dmu_free_object(os, obj); + } + if (err != ESRCH) + goto out; + + /* + * Only the ZIL knows how to free log blocks. + */ + zil_destroy(dmu_objset_zil(os), B_FALSE); + + /* + * Sync out all in-flight IO. + */ + txg_wait_synced(dd->dd_pool, 0); + + /* + * If we managed to free all the objects in open + * context, the user space accounting should be zero. + */ + if (ds->ds_phys->ds_bp.blk_fill == 0 && + dmu_objset_userused_enabled(os)) { + uint64_t count; + + ASSERT(zap_count(os, DMU_USERUSED_OBJECT, &count) != 0 || + count == 0); + ASSERT(zap_count(os, DMU_GROUPUSED_OBJECT, &count) != 0 || + count == 0); + } + + rw_enter(&dd->dd_pool->dp_config_rwlock, RW_READER); + err = dsl_dir_open_obj(dd->dd_pool, dd->dd_object, NULL, FTAG, &dd); + rw_exit(&dd->dd_pool->dp_config_rwlock); + + if (err) + goto out; + + /* + * Blow away the dsl_dir + head dataset. + */ + dsl_dataset_make_exclusive(ds, tag); + /* + * If we're removing a clone, we might also need to remove its + * origin. + */ + do { + dsda.need_prep = B_FALSE; + if (dsl_dir_is_clone(dd)) { + err = dsl_dataset_origin_rm_prep(&dsda, tag); + if (err) { + dsl_dir_close(dd, FTAG); + goto out; + } + } + + dstg = dsl_sync_task_group_create(ds->ds_dir->dd_pool); + dsl_sync_task_create(dstg, dsl_dataset_destroy_check, + dsl_dataset_destroy_sync, &dsda, tag, 0); + dsl_sync_task_create(dstg, dsl_dir_destroy_check, + dsl_dir_destroy_sync, &dummy_ds, FTAG, 0); + err = dsl_sync_task_group_wait(dstg); + dsl_sync_task_group_destroy(dstg); + + /* + * We could be racing against 'zfs release' or 'zfs destroy -d' + * on the origin snap, in which case we can get EBUSY if we + * needed to destroy the origin snap but were not ready to + * do so. + */ + if (dsda.need_prep) { + ASSERT(err == EBUSY); + ASSERT(dsl_dir_is_clone(dd)); + ASSERT(dsda.rm_origin == NULL); + } + } while (dsda.need_prep); + + if (dsda.rm_origin != NULL) + dsl_dataset_disown(dsda.rm_origin, tag); + + /* if it is successful, dsl_dir_destroy_sync will close the dd */ + if (err) + dsl_dir_close(dd, FTAG); +out: + dsl_dataset_disown(ds, tag); + return (err); +} + +blkptr_t * +dsl_dataset_get_blkptr(dsl_dataset_t *ds) +{ + return (&ds->ds_phys->ds_bp); +} + +void +dsl_dataset_set_blkptr(dsl_dataset_t *ds, blkptr_t *bp, dmu_tx_t *tx) +{ + ASSERT(dmu_tx_is_syncing(tx)); + /* If it's the meta-objset, set dp_meta_rootbp */ + if (ds == NULL) { + tx->tx_pool->dp_meta_rootbp = *bp; + } else { + dmu_buf_will_dirty(ds->ds_dbuf, tx); + ds->ds_phys->ds_bp = *bp; + } +} + +spa_t * +dsl_dataset_get_spa(dsl_dataset_t *ds) +{ + return (ds->ds_dir->dd_pool->dp_spa); +} + +void +dsl_dataset_dirty(dsl_dataset_t *ds, dmu_tx_t *tx) +{ + dsl_pool_t *dp; + + if (ds == NULL) /* this is the meta-objset */ + return; + + ASSERT(ds->ds_objset != NULL); + + if (ds->ds_phys->ds_next_snap_obj != 0) + panic("dirtying snapshot!"); + + dp = ds->ds_dir->dd_pool; + + if (txg_list_add(&dp->dp_dirty_datasets, ds, tx->tx_txg) == 0) { + /* up the hold count until we can be written out */ + dmu_buf_add_ref(ds->ds_dbuf, ds); + } +} + +/* + * The unique space in the head dataset can be calculated by subtracting + * the space used in the most recent snapshot, that is still being used + * in this file system, from the space currently in use. To figure out + * the space in the most recent snapshot still in use, we need to take + * the total space used in the snapshot and subtract out the space that + * has been freed up since the snapshot was taken. + */ +static void +dsl_dataset_recalc_head_uniq(dsl_dataset_t *ds) +{ + uint64_t mrs_used; + uint64_t dlused, dlcomp, dluncomp; + + ASSERT(!dsl_dataset_is_snapshot(ds)); + + if (ds->ds_phys->ds_prev_snap_obj != 0) + mrs_used = ds->ds_prev->ds_phys->ds_used_bytes; + else + mrs_used = 0; + + dsl_deadlist_space(&ds->ds_deadlist, &dlused, &dlcomp, &dluncomp); + + ASSERT3U(dlused, <=, mrs_used); + ds->ds_phys->ds_unique_bytes = + ds->ds_phys->ds_used_bytes - (mrs_used - dlused); + + if (spa_version(ds->ds_dir->dd_pool->dp_spa) >= + SPA_VERSION_UNIQUE_ACCURATE) + ds->ds_phys->ds_flags |= DS_FLAG_UNIQUE_ACCURATE; +} + +struct killarg { + dsl_dataset_t *ds; + dmu_tx_t *tx; +}; + +/* ARGSUSED */ +static int +kill_blkptr(spa_t *spa, zilog_t *zilog, const blkptr_t *bp, arc_buf_t *pbuf, + const zbookmark_t *zb, const dnode_phys_t *dnp, void *arg) +{ + struct killarg *ka = arg; + dmu_tx_t *tx = ka->tx; + + if (bp == NULL) + return (0); + + if (zb->zb_level == ZB_ZIL_LEVEL) { + ASSERT(zilog != NULL); + /* + * It's a block in the intent log. It has no + * accounting, so just free it. + */ + dsl_free(ka->tx->tx_pool, ka->tx->tx_txg, bp); + } else { + ASSERT(zilog == NULL); + ASSERT3U(bp->blk_birth, >, ka->ds->ds_phys->ds_prev_snap_txg); + (void) dsl_dataset_block_kill(ka->ds, bp, tx, B_FALSE); + } + + return (0); +} + +/* ARGSUSED */ +static int +dsl_dataset_destroy_begin_check(void *arg1, void *arg2, dmu_tx_t *tx) +{ + dsl_dataset_t *ds = arg1; + objset_t *mos = ds->ds_dir->dd_pool->dp_meta_objset; + uint64_t count; + int err; + + /* + * Can't delete a head dataset if there are snapshots of it. + * (Except if the only snapshots are from the branch we cloned + * from.) + */ + if (ds->ds_prev != NULL && + ds->ds_prev->ds_phys->ds_next_snap_obj == ds->ds_object) + return (EBUSY); + + /* + * This is really a dsl_dir thing, but check it here so that + * we'll be less likely to leave this dataset inconsistent & + * nearly destroyed. + */ + err = zap_count(mos, ds->ds_dir->dd_phys->dd_child_dir_zapobj, &count); + if (err) + return (err); + if (count != 0) + return (EEXIST); + + return (0); +} + +/* ARGSUSED */ +static void +dsl_dataset_destroy_begin_sync(void *arg1, void *arg2, dmu_tx_t *tx) +{ + dsl_dataset_t *ds = arg1; + dsl_pool_t *dp = ds->ds_dir->dd_pool; + + /* Mark it as inconsistent on-disk, in case we crash */ + dmu_buf_will_dirty(ds->ds_dbuf, tx); + ds->ds_phys->ds_flags |= DS_FLAG_INCONSISTENT; + + spa_history_log_internal(LOG_DS_DESTROY_BEGIN, dp->dp_spa, tx, + "dataset = %llu", ds->ds_object); +} + +static int +dsl_dataset_origin_check(struct dsl_ds_destroyarg *dsda, void *tag, + dmu_tx_t *tx) +{ + dsl_dataset_t *ds = dsda->ds; + dsl_dataset_t *ds_prev = ds->ds_prev; + + if (dsl_dataset_might_destroy_origin(ds_prev)) { + struct dsl_ds_destroyarg ndsda = {0}; + + /* + * If we're not prepared to remove the origin, don't remove + * the clone either. + */ + if (dsda->rm_origin == NULL) { + dsda->need_prep = B_TRUE; + return (EBUSY); + } + + ndsda.ds = ds_prev; + ndsda.is_origin_rm = B_TRUE; + return (dsl_dataset_destroy_check(&ndsda, tag, tx)); + } + + /* + * If we're not going to remove the origin after all, + * undo the open context setup. + */ + if (dsda->rm_origin != NULL) { + dsl_dataset_disown(dsda->rm_origin, tag); + dsda->rm_origin = NULL; + } + + return (0); +} + +/* + * If you add new checks here, you may need to add + * additional checks to the "temporary" case in + * snapshot_check() in dmu_objset.c. + */ +/* ARGSUSED */ +int +dsl_dataset_destroy_check(void *arg1, void *arg2, dmu_tx_t *tx) +{ + struct dsl_ds_destroyarg *dsda = arg1; + dsl_dataset_t *ds = dsda->ds; + + /* we have an owner hold, so noone else can destroy us */ + ASSERT(!DSL_DATASET_IS_DESTROYED(ds)); + + /* + * Only allow deferred destroy on pools that support it. + * NOTE: deferred destroy is only supported on snapshots. + */ + if (dsda->defer) { + if (spa_version(ds->ds_dir->dd_pool->dp_spa) < + SPA_VERSION_USERREFS) + return (ENOTSUP); + ASSERT(dsl_dataset_is_snapshot(ds)); + return (0); + } + + /* + * Can't delete a head dataset if there are snapshots of it. + * (Except if the only snapshots are from the branch we cloned + * from.) + */ + if (ds->ds_prev != NULL && + ds->ds_prev->ds_phys->ds_next_snap_obj == ds->ds_object) + return (EBUSY); + + /* + * If we made changes this txg, traverse_dsl_dataset won't find + * them. Try again. + */ + if (ds->ds_phys->ds_bp.blk_birth >= tx->tx_txg) + return (EAGAIN); + + if (dsl_dataset_is_snapshot(ds)) { + /* + * If this snapshot has an elevated user reference count, + * we can't destroy it yet. + */ + if (ds->ds_userrefs > 0 && !dsda->releasing) + return (EBUSY); + + mutex_enter(&ds->ds_lock); + /* + * Can't delete a branch point. However, if we're destroying + * a clone and removing its origin due to it having a user + * hold count of 0 and having been marked for deferred destroy, + * it's OK for the origin to have a single clone. + */ + if (ds->ds_phys->ds_num_children > + (dsda->is_origin_rm ? 2 : 1)) { + mutex_exit(&ds->ds_lock); + return (EEXIST); + } + mutex_exit(&ds->ds_lock); + } else if (dsl_dir_is_clone(ds->ds_dir)) { + return (dsl_dataset_origin_check(dsda, arg2, tx)); + } + + /* XXX we should do some i/o error checking... */ + return (0); +} + +struct refsarg { + kmutex_t lock; + boolean_t gone; + kcondvar_t cv; +}; + +/* ARGSUSED */ +static void +dsl_dataset_refs_gone(dmu_buf_t *db, void *argv) +{ + struct refsarg *arg = argv; + + mutex_enter(&arg->lock); + arg->gone = TRUE; + cv_signal(&arg->cv); + mutex_exit(&arg->lock); +} + +static void +dsl_dataset_drain_refs(dsl_dataset_t *ds, void *tag) +{ + struct refsarg arg; + + mutex_init(&arg.lock, NULL, MUTEX_DEFAULT, NULL); + cv_init(&arg.cv, NULL, CV_DEFAULT, NULL); + arg.gone = FALSE; + (void) dmu_buf_update_user(ds->ds_dbuf, ds, &arg, &ds->ds_phys, + dsl_dataset_refs_gone); + dmu_buf_rele(ds->ds_dbuf, tag); + mutex_enter(&arg.lock); + while (!arg.gone) + cv_wait(&arg.cv, &arg.lock); + ASSERT(arg.gone); + mutex_exit(&arg.lock); + ds->ds_dbuf = NULL; + ds->ds_phys = NULL; + mutex_destroy(&arg.lock); + cv_destroy(&arg.cv); +} + +static void +remove_from_next_clones(dsl_dataset_t *ds, uint64_t obj, dmu_tx_t *tx) +{ + objset_t *mos = ds->ds_dir->dd_pool->dp_meta_objset; + uint64_t count; + int err; + + ASSERT(ds->ds_phys->ds_num_children >= 2); + err = zap_remove_int(mos, ds->ds_phys->ds_next_clones_obj, obj, tx); + /* + * The err should not be ENOENT, but a bug in a previous version + * of the code could cause upgrade_clones_cb() to not set + * ds_next_snap_obj when it should, leading to a missing entry. + * If we knew that the pool was created after + * SPA_VERSION_NEXT_CLONES, we could assert that it isn't + * ENOENT. However, at least we can check that we don't have + * too many entries in the next_clones_obj even after failing to + * remove this one. + */ + if (err != ENOENT) { + VERIFY3U(err, ==, 0); + } + ASSERT3U(0, ==, zap_count(mos, ds->ds_phys->ds_next_clones_obj, + &count)); + ASSERT3U(count, <=, ds->ds_phys->ds_num_children - 2); +} + +static void +dsl_dataset_remove_clones_key(dsl_dataset_t *ds, uint64_t mintxg, dmu_tx_t *tx) +{ + objset_t *mos = ds->ds_dir->dd_pool->dp_meta_objset; + zap_cursor_t zc; + zap_attribute_t za; + + /* + * If it is the old version, dd_clones doesn't exist so we can't + * find the clones, but deadlist_remove_key() is a no-op so it + * doesn't matter. + */ + if (ds->ds_dir->dd_phys->dd_clones == 0) + return; + + for (zap_cursor_init(&zc, mos, ds->ds_dir->dd_phys->dd_clones); + zap_cursor_retrieve(&zc, &za) == 0; + zap_cursor_advance(&zc)) { + dsl_dataset_t *clone; + + VERIFY3U(0, ==, dsl_dataset_hold_obj(ds->ds_dir->dd_pool, + za.za_first_integer, FTAG, &clone)); + if (clone->ds_dir->dd_origin_txg > mintxg) { + dsl_deadlist_remove_key(&clone->ds_deadlist, + mintxg, tx); + dsl_dataset_remove_clones_key(clone, mintxg, tx); + } + dsl_dataset_rele(clone, FTAG); + } + zap_cursor_fini(&zc); +} + +struct process_old_arg { + dsl_dataset_t *ds; + dsl_dataset_t *ds_prev; + boolean_t after_branch_point; + zio_t *pio; + uint64_t used, comp, uncomp; +}; + +static int +process_old_cb(void *arg, const blkptr_t *bp, dmu_tx_t *tx) +{ + struct process_old_arg *poa = arg; + dsl_pool_t *dp = poa->ds->ds_dir->dd_pool; + + if (bp->blk_birth <= poa->ds->ds_phys->ds_prev_snap_txg) { + dsl_deadlist_insert(&poa->ds->ds_deadlist, bp, tx); + if (poa->ds_prev && !poa->after_branch_point && + bp->blk_birth > + poa->ds_prev->ds_phys->ds_prev_snap_txg) { + poa->ds_prev->ds_phys->ds_unique_bytes += + bp_get_dsize_sync(dp->dp_spa, bp); + } + } else { + poa->used += bp_get_dsize_sync(dp->dp_spa, bp); + poa->comp += BP_GET_PSIZE(bp); + poa->uncomp += BP_GET_UCSIZE(bp); + dsl_free_sync(poa->pio, dp, tx->tx_txg, bp); + } + return (0); +} + +static void +process_old_deadlist(dsl_dataset_t *ds, dsl_dataset_t *ds_prev, + dsl_dataset_t *ds_next, boolean_t after_branch_point, dmu_tx_t *tx) +{ + struct process_old_arg poa = { 0 }; + dsl_pool_t *dp = ds->ds_dir->dd_pool; + objset_t *mos = dp->dp_meta_objset; + + ASSERT(ds->ds_deadlist.dl_oldfmt); + ASSERT(ds_next->ds_deadlist.dl_oldfmt); + + poa.ds = ds; + poa.ds_prev = ds_prev; + poa.after_branch_point = after_branch_point; + poa.pio = zio_root(dp->dp_spa, NULL, NULL, ZIO_FLAG_MUSTSUCCEED); + VERIFY3U(0, ==, bpobj_iterate(&ds_next->ds_deadlist.dl_bpobj, + process_old_cb, &poa, tx)); + VERIFY3U(zio_wait(poa.pio), ==, 0); + ASSERT3U(poa.used, ==, ds->ds_phys->ds_unique_bytes); + + /* change snapused */ + dsl_dir_diduse_space(ds->ds_dir, DD_USED_SNAP, + -poa.used, -poa.comp, -poa.uncomp, tx); + + /* swap next's deadlist to our deadlist */ + dsl_deadlist_close(&ds->ds_deadlist); + dsl_deadlist_close(&ds_next->ds_deadlist); + SWITCH64(ds_next->ds_phys->ds_deadlist_obj, + ds->ds_phys->ds_deadlist_obj); + dsl_deadlist_open(&ds->ds_deadlist, mos, ds->ds_phys->ds_deadlist_obj); + dsl_deadlist_open(&ds_next->ds_deadlist, mos, + ds_next->ds_phys->ds_deadlist_obj); +} + +void +dsl_dataset_destroy_sync(void *arg1, void *tag, dmu_tx_t *tx) +{ + struct dsl_ds_destroyarg *dsda = arg1; + dsl_dataset_t *ds = dsda->ds; + int err; + int after_branch_point = FALSE; + dsl_pool_t *dp = ds->ds_dir->dd_pool; + objset_t *mos = dp->dp_meta_objset; + dsl_dataset_t *ds_prev = NULL; + boolean_t wont_destroy; + uint64_t obj; + + wont_destroy = (dsda->defer && + (ds->ds_userrefs > 0 || ds->ds_phys->ds_num_children > 1)); + + ASSERT(ds->ds_owner || wont_destroy); + ASSERT(dsda->defer || ds->ds_phys->ds_num_children <= 1); + ASSERT(ds->ds_prev == NULL || + ds->ds_prev->ds_phys->ds_next_snap_obj != ds->ds_object); + ASSERT3U(ds->ds_phys->ds_bp.blk_birth, <=, tx->tx_txg); + + if (wont_destroy) { + ASSERT(spa_version(dp->dp_spa) >= SPA_VERSION_USERREFS); + dmu_buf_will_dirty(ds->ds_dbuf, tx); + ds->ds_phys->ds_flags |= DS_FLAG_DEFER_DESTROY; + return; + } + + /* signal any waiters that this dataset is going away */ + mutex_enter(&ds->ds_lock); + ds->ds_owner = dsl_reaper; + cv_broadcast(&ds->ds_exclusive_cv); + mutex_exit(&ds->ds_lock); + + /* Remove our reservation */ + if (ds->ds_reserved != 0) { + dsl_prop_setarg_t psa; + uint64_t value = 0; + + dsl_prop_setarg_init_uint64(&psa, "refreservation", + (ZPROP_SRC_NONE | ZPROP_SRC_LOCAL | ZPROP_SRC_RECEIVED), + &value); + psa.psa_effective_value = 0; /* predict default value */ + + dsl_dataset_set_reservation_sync(ds, &psa, tx); + ASSERT3U(ds->ds_reserved, ==, 0); + } + + ASSERT(RW_WRITE_HELD(&dp->dp_config_rwlock)); + + dsl_scan_ds_destroyed(ds, tx); + + obj = ds->ds_object; + + if (ds->ds_phys->ds_prev_snap_obj != 0) { + if (ds->ds_prev) { + ds_prev = ds->ds_prev; + } else { + VERIFY(0 == dsl_dataset_hold_obj(dp, + ds->ds_phys->ds_prev_snap_obj, FTAG, &ds_prev)); + } + after_branch_point = + (ds_prev->ds_phys->ds_next_snap_obj != obj); + + dmu_buf_will_dirty(ds_prev->ds_dbuf, tx); + if (after_branch_point && + ds_prev->ds_phys->ds_next_clones_obj != 0) { + remove_from_next_clones(ds_prev, obj, tx); + if (ds->ds_phys->ds_next_snap_obj != 0) { + VERIFY(0 == zap_add_int(mos, + ds_prev->ds_phys->ds_next_clones_obj, + ds->ds_phys->ds_next_snap_obj, tx)); + } + } + if (after_branch_point && + ds->ds_phys->ds_next_snap_obj == 0) { + /* This clone is toast. */ + ASSERT(ds_prev->ds_phys->ds_num_children > 1); + ds_prev->ds_phys->ds_num_children--; + + /* + * If the clone's origin has no other clones, no + * user holds, and has been marked for deferred + * deletion, then we should have done the necessary + * destroy setup for it. + */ + if (ds_prev->ds_phys->ds_num_children == 1 && + ds_prev->ds_userrefs == 0 && + DS_IS_DEFER_DESTROY(ds_prev)) { + ASSERT3P(dsda->rm_origin, !=, NULL); + } else { + ASSERT3P(dsda->rm_origin, ==, NULL); + } + } else if (!after_branch_point) { + ds_prev->ds_phys->ds_next_snap_obj = + ds->ds_phys->ds_next_snap_obj; + } + } + + if (dsl_dataset_is_snapshot(ds)) { + dsl_dataset_t *ds_next; + uint64_t old_unique; + uint64_t used = 0, comp = 0, uncomp = 0; + + VERIFY(0 == dsl_dataset_hold_obj(dp, + ds->ds_phys->ds_next_snap_obj, FTAG, &ds_next)); + ASSERT3U(ds_next->ds_phys->ds_prev_snap_obj, ==, obj); + + old_unique = ds_next->ds_phys->ds_unique_bytes; + + dmu_buf_will_dirty(ds_next->ds_dbuf, tx); + ds_next->ds_phys->ds_prev_snap_obj = + ds->ds_phys->ds_prev_snap_obj; + ds_next->ds_phys->ds_prev_snap_txg = + ds->ds_phys->ds_prev_snap_txg; + ASSERT3U(ds->ds_phys->ds_prev_snap_txg, ==, + ds_prev ? ds_prev->ds_phys->ds_creation_txg : 0); + + + if (ds_next->ds_deadlist.dl_oldfmt) { + process_old_deadlist(ds, ds_prev, ds_next, + after_branch_point, tx); + } else { + /* Adjust prev's unique space. */ + if (ds_prev && !after_branch_point) { + dsl_deadlist_space_range(&ds_next->ds_deadlist, + ds_prev->ds_phys->ds_prev_snap_txg, + ds->ds_phys->ds_prev_snap_txg, + &used, &comp, &uncomp); + ds_prev->ds_phys->ds_unique_bytes += used; + } + + /* Adjust snapused. */ + dsl_deadlist_space_range(&ds_next->ds_deadlist, + ds->ds_phys->ds_prev_snap_txg, UINT64_MAX, + &used, &comp, &uncomp); + dsl_dir_diduse_space(ds->ds_dir, DD_USED_SNAP, + -used, -comp, -uncomp, tx); + + /* Move blocks to be freed to pool's free list. */ + dsl_deadlist_move_bpobj(&ds_next->ds_deadlist, + &dp->dp_free_bpobj, ds->ds_phys->ds_prev_snap_txg, + tx); + dsl_dir_diduse_space(tx->tx_pool->dp_free_dir, + DD_USED_HEAD, used, comp, uncomp, tx); + dsl_dir_dirty(tx->tx_pool->dp_free_dir, tx); + + /* Merge our deadlist into next's and free it. */ + dsl_deadlist_merge(&ds_next->ds_deadlist, + ds->ds_phys->ds_deadlist_obj, tx); + } + dsl_deadlist_close(&ds->ds_deadlist); + dsl_deadlist_free(mos, ds->ds_phys->ds_deadlist_obj, tx); + + /* Collapse range in clone heads */ + dsl_dataset_remove_clones_key(ds, + ds->ds_phys->ds_creation_txg, tx); + + if (dsl_dataset_is_snapshot(ds_next)) { + dsl_dataset_t *ds_nextnext; + + /* + * Update next's unique to include blocks which + * were previously shared by only this snapshot + * and it. Those blocks will be born after the + * prev snap and before this snap, and will have + * died after the next snap and before the one + * after that (ie. be on the snap after next's + * deadlist). + */ + VERIFY(0 == dsl_dataset_hold_obj(dp, + ds_next->ds_phys->ds_next_snap_obj, + FTAG, &ds_nextnext)); + dsl_deadlist_space_range(&ds_nextnext->ds_deadlist, + ds->ds_phys->ds_prev_snap_txg, + ds->ds_phys->ds_creation_txg, + &used, &comp, &uncomp); + ds_next->ds_phys->ds_unique_bytes += used; + dsl_dataset_rele(ds_nextnext, FTAG); + ASSERT3P(ds_next->ds_prev, ==, NULL); + + /* Collapse range in this head. */ + dsl_dataset_t *hds; + VERIFY3U(0, ==, dsl_dataset_hold_obj(dp, + ds->ds_dir->dd_phys->dd_head_dataset_obj, + FTAG, &hds)); + dsl_deadlist_remove_key(&hds->ds_deadlist, + ds->ds_phys->ds_creation_txg, tx); + dsl_dataset_rele(hds, FTAG); + + } else { + ASSERT3P(ds_next->ds_prev, ==, ds); + dsl_dataset_drop_ref(ds_next->ds_prev, ds_next); + ds_next->ds_prev = NULL; + if (ds_prev) { + VERIFY(0 == dsl_dataset_get_ref(dp, + ds->ds_phys->ds_prev_snap_obj, + ds_next, &ds_next->ds_prev)); + } + + dsl_dataset_recalc_head_uniq(ds_next); + + /* + * Reduce the amount of our unconsmed refreservation + * being charged to our parent by the amount of + * new unique data we have gained. + */ + if (old_unique < ds_next->ds_reserved) { + int64_t mrsdelta; + uint64_t new_unique = + ds_next->ds_phys->ds_unique_bytes; + + ASSERT(old_unique <= new_unique); + mrsdelta = MIN(new_unique - old_unique, + ds_next->ds_reserved - old_unique); + dsl_dir_diduse_space(ds->ds_dir, + DD_USED_REFRSRV, -mrsdelta, 0, 0, tx); + } + } + dsl_dataset_rele(ds_next, FTAG); + } else { + /* + * There's no next snapshot, so this is a head dataset. + * Destroy the deadlist. Unless it's a clone, the + * deadlist should be empty. (If it's a clone, it's + * safe to ignore the deadlist contents.) + */ + struct killarg ka; + + dsl_deadlist_close(&ds->ds_deadlist); + dsl_deadlist_free(mos, ds->ds_phys->ds_deadlist_obj, tx); + ds->ds_phys->ds_deadlist_obj = 0; + + /* + * Free everything that we point to (that's born after + * the previous snapshot, if we are a clone) + * + * NB: this should be very quick, because we already + * freed all the objects in open context. + */ + ka.ds = ds; + ka.tx = tx; + err = traverse_dataset(ds, ds->ds_phys->ds_prev_snap_txg, + TRAVERSE_POST, kill_blkptr, &ka); + ASSERT3U(err, ==, 0); + ASSERT(!DS_UNIQUE_IS_ACCURATE(ds) || + ds->ds_phys->ds_unique_bytes == 0); + + if (ds->ds_prev != NULL) { + if (spa_version(dp->dp_spa) >= SPA_VERSION_DIR_CLONES) { + VERIFY3U(0, ==, zap_remove_int(mos, + ds->ds_prev->ds_dir->dd_phys->dd_clones, + ds->ds_object, tx)); + } + dsl_dataset_rele(ds->ds_prev, ds); + ds->ds_prev = ds_prev = NULL; + } + } + + /* + * This must be done after the dsl_traverse(), because it will + * re-open the objset. + */ + if (ds->ds_objset) { + dmu_objset_evict(ds->ds_objset); + ds->ds_objset = NULL; + } + + if (ds->ds_dir->dd_phys->dd_head_dataset_obj == ds->ds_object) { + /* Erase the link in the dir */ + dmu_buf_will_dirty(ds->ds_dir->dd_dbuf, tx); + ds->ds_dir->dd_phys->dd_head_dataset_obj = 0; + ASSERT(ds->ds_phys->ds_snapnames_zapobj != 0); + err = zap_destroy(mos, ds->ds_phys->ds_snapnames_zapobj, tx); + ASSERT(err == 0); + } else { + /* remove from snapshot namespace */ + dsl_dataset_t *ds_head; + ASSERT(ds->ds_phys->ds_snapnames_zapobj == 0); + VERIFY(0 == dsl_dataset_hold_obj(dp, + ds->ds_dir->dd_phys->dd_head_dataset_obj, FTAG, &ds_head)); + VERIFY(0 == dsl_dataset_get_snapname(ds)); +#ifdef ZFS_DEBUG + { + uint64_t val; + + err = dsl_dataset_snap_lookup(ds_head, + ds->ds_snapname, &val); + ASSERT3U(err, ==, 0); + ASSERT3U(val, ==, obj); + } +#endif + err = dsl_dataset_snap_remove(ds_head, ds->ds_snapname, tx); + ASSERT(err == 0); + dsl_dataset_rele(ds_head, FTAG); + } + + if (ds_prev && ds->ds_prev != ds_prev) + dsl_dataset_rele(ds_prev, FTAG); + + spa_prop_clear_bootfs(dp->dp_spa, ds->ds_object, tx); + spa_history_log_internal(LOG_DS_DESTROY, dp->dp_spa, tx, + "dataset = %llu", ds->ds_object); + + if (ds->ds_phys->ds_next_clones_obj != 0) { + uint64_t count; + ASSERT(0 == zap_count(mos, + ds->ds_phys->ds_next_clones_obj, &count) && count == 0); + VERIFY(0 == dmu_object_free(mos, + ds->ds_phys->ds_next_clones_obj, tx)); + } + if (ds->ds_phys->ds_props_obj != 0) + VERIFY(0 == zap_destroy(mos, ds->ds_phys->ds_props_obj, tx)); + if (ds->ds_phys->ds_userrefs_obj != 0) + VERIFY(0 == zap_destroy(mos, ds->ds_phys->ds_userrefs_obj, tx)); + dsl_dir_close(ds->ds_dir, ds); + ds->ds_dir = NULL; + dsl_dataset_drain_refs(ds, tag); + VERIFY(0 == dmu_object_free(mos, obj, tx)); + + if (dsda->rm_origin) { + /* + * Remove the origin of the clone we just destroyed. + */ + struct dsl_ds_destroyarg ndsda = {0}; + + ndsda.ds = dsda->rm_origin; + dsl_dataset_destroy_sync(&ndsda, tag, tx); + } +} + +static int +dsl_dataset_snapshot_reserve_space(dsl_dataset_t *ds, dmu_tx_t *tx) +{ + uint64_t asize; + + if (!dmu_tx_is_syncing(tx)) + return (0); + + /* + * If there's an fs-only reservation, any blocks that might become + * owned by the snapshot dataset must be accommodated by space + * outside of the reservation. + */ + ASSERT(ds->ds_reserved == 0 || DS_UNIQUE_IS_ACCURATE(ds)); + asize = MIN(ds->ds_phys->ds_unique_bytes, ds->ds_reserved); + if (asize > dsl_dir_space_available(ds->ds_dir, NULL, 0, TRUE)) + return (ENOSPC); + + /* + * Propogate any reserved space for this snapshot to other + * snapshot checks in this sync group. + */ + if (asize > 0) + dsl_dir_willuse_space(ds->ds_dir, asize, tx); + + return (0); +} + +int +dsl_dataset_snapshot_check(void *arg1, void *arg2, dmu_tx_t *tx) +{ + dsl_dataset_t *ds = arg1; + const char *snapname = arg2; + int err; + uint64_t value; + + /* + * We don't allow multiple snapshots of the same txg. If there + * is already one, try again. + */ + if (ds->ds_phys->ds_prev_snap_txg >= tx->tx_txg) + return (EAGAIN); + + /* + * Check for conflicting name snapshot name. + */ + err = dsl_dataset_snap_lookup(ds, snapname, &value); + if (err == 0) + return (EEXIST); + if (err != ENOENT) + return (err); + + /* + * Check that the dataset's name is not too long. Name consists + * of the dataset's length + 1 for the @-sign + snapshot name's length + */ + if (dsl_dataset_namelen(ds) + 1 + strlen(snapname) >= MAXNAMELEN) + return (ENAMETOOLONG); + + err = dsl_dataset_snapshot_reserve_space(ds, tx); + if (err) + return (err); + + ds->ds_trysnap_txg = tx->tx_txg; + return (0); +} + +void +dsl_dataset_snapshot_sync(void *arg1, void *arg2, dmu_tx_t *tx) +{ + dsl_dataset_t *ds = arg1; + const char *snapname = arg2; + dsl_pool_t *dp = ds->ds_dir->dd_pool; + dmu_buf_t *dbuf; + dsl_dataset_phys_t *dsphys; + uint64_t dsobj, crtxg; + objset_t *mos = dp->dp_meta_objset; + int err; + + ASSERT(RW_WRITE_HELD(&dp->dp_config_rwlock)); + + /* + * The origin's ds_creation_txg has to be < TXG_INITIAL + */ + if (strcmp(snapname, ORIGIN_DIR_NAME) == 0) + crtxg = 1; + else + crtxg = tx->tx_txg; + + dsobj = dmu_object_alloc(mos, DMU_OT_DSL_DATASET, 0, + DMU_OT_DSL_DATASET, sizeof (dsl_dataset_phys_t), tx); + VERIFY(0 == dmu_bonus_hold(mos, dsobj, FTAG, &dbuf)); + dmu_buf_will_dirty(dbuf, tx); + dsphys = dbuf->db_data; + bzero(dsphys, sizeof (dsl_dataset_phys_t)); + dsphys->ds_dir_obj = ds->ds_dir->dd_object; + dsphys->ds_fsid_guid = unique_create(); + (void) random_get_pseudo_bytes((void*)&dsphys->ds_guid, + sizeof (dsphys->ds_guid)); + dsphys->ds_prev_snap_obj = ds->ds_phys->ds_prev_snap_obj; + dsphys->ds_prev_snap_txg = ds->ds_phys->ds_prev_snap_txg; + dsphys->ds_next_snap_obj = ds->ds_object; + dsphys->ds_num_children = 1; + dsphys->ds_creation_time = gethrestime_sec(); + dsphys->ds_creation_txg = crtxg; + dsphys->ds_deadlist_obj = ds->ds_phys->ds_deadlist_obj; + dsphys->ds_used_bytes = ds->ds_phys->ds_used_bytes; + dsphys->ds_compressed_bytes = ds->ds_phys->ds_compressed_bytes; + dsphys->ds_uncompressed_bytes = ds->ds_phys->ds_uncompressed_bytes; + dsphys->ds_flags = ds->ds_phys->ds_flags; + dsphys->ds_bp = ds->ds_phys->ds_bp; + dmu_buf_rele(dbuf, FTAG); + + ASSERT3U(ds->ds_prev != 0, ==, ds->ds_phys->ds_prev_snap_obj != 0); + if (ds->ds_prev) { + uint64_t next_clones_obj = + ds->ds_prev->ds_phys->ds_next_clones_obj; + ASSERT(ds->ds_prev->ds_phys->ds_next_snap_obj == + ds->ds_object || + ds->ds_prev->ds_phys->ds_num_children > 1); + if (ds->ds_prev->ds_phys->ds_next_snap_obj == ds->ds_object) { + dmu_buf_will_dirty(ds->ds_prev->ds_dbuf, tx); + ASSERT3U(ds->ds_phys->ds_prev_snap_txg, ==, + ds->ds_prev->ds_phys->ds_creation_txg); + ds->ds_prev->ds_phys->ds_next_snap_obj = dsobj; + } else if (next_clones_obj != 0) { + remove_from_next_clones(ds->ds_prev, + dsphys->ds_next_snap_obj, tx); + VERIFY3U(0, ==, zap_add_int(mos, + next_clones_obj, dsobj, tx)); + } + } + + /* + * If we have a reference-reservation on this dataset, we will + * need to increase the amount of refreservation being charged + * since our unique space is going to zero. + */ + if (ds->ds_reserved) { + int64_t delta; + ASSERT(DS_UNIQUE_IS_ACCURATE(ds)); + delta = MIN(ds->ds_phys->ds_unique_bytes, ds->ds_reserved); + dsl_dir_diduse_space(ds->ds_dir, DD_USED_REFRSRV, + delta, 0, 0, tx); + } + + dmu_buf_will_dirty(ds->ds_dbuf, tx); + zfs_dbgmsg("taking snapshot %s@%s/%llu; newkey=%llu", + ds->ds_dir->dd_myname, snapname, dsobj, + ds->ds_phys->ds_prev_snap_txg); + ds->ds_phys->ds_deadlist_obj = dsl_deadlist_clone(&ds->ds_deadlist, + UINT64_MAX, ds->ds_phys->ds_prev_snap_obj, tx); + dsl_deadlist_close(&ds->ds_deadlist); + dsl_deadlist_open(&ds->ds_deadlist, mos, ds->ds_phys->ds_deadlist_obj); + dsl_deadlist_add_key(&ds->ds_deadlist, + ds->ds_phys->ds_prev_snap_txg, tx); + + ASSERT3U(ds->ds_phys->ds_prev_snap_txg, <, tx->tx_txg); + ds->ds_phys->ds_prev_snap_obj = dsobj; + ds->ds_phys->ds_prev_snap_txg = crtxg; + ds->ds_phys->ds_unique_bytes = 0; + if (spa_version(dp->dp_spa) >= SPA_VERSION_UNIQUE_ACCURATE) + ds->ds_phys->ds_flags |= DS_FLAG_UNIQUE_ACCURATE; + + err = zap_add(mos, ds->ds_phys->ds_snapnames_zapobj, + snapname, 8, 1, &dsobj, tx); + ASSERT(err == 0); + + if (ds->ds_prev) + dsl_dataset_drop_ref(ds->ds_prev, ds); + VERIFY(0 == dsl_dataset_get_ref(dp, + ds->ds_phys->ds_prev_snap_obj, ds, &ds->ds_prev)); + + dsl_scan_ds_snapshotted(ds, tx); + + dsl_dir_snap_cmtime_update(ds->ds_dir); + + spa_history_log_internal(LOG_DS_SNAPSHOT, dp->dp_spa, tx, + "dataset = %llu", dsobj); +} + +void +dsl_dataset_sync(dsl_dataset_t *ds, zio_t *zio, dmu_tx_t *tx) +{ + ASSERT(dmu_tx_is_syncing(tx)); + ASSERT(ds->ds_objset != NULL); + ASSERT(ds->ds_phys->ds_next_snap_obj == 0); + + /* + * in case we had to change ds_fsid_guid when we opened it, + * sync it out now. + */ + dmu_buf_will_dirty(ds->ds_dbuf, tx); + ds->ds_phys->ds_fsid_guid = ds->ds_fsid_guid; + + dsl_dir_dirty(ds->ds_dir, tx); + dmu_objset_sync(ds->ds_objset, zio, tx); +} + +void +dsl_dataset_stats(dsl_dataset_t *ds, nvlist_t *nv) +{ + uint64_t refd, avail, uobjs, aobjs; + + dsl_dir_stats(ds->ds_dir, nv); + + dsl_dataset_space(ds, &refd, &avail, &uobjs, &aobjs); + dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_AVAILABLE, avail); + dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_REFERENCED, refd); + + dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_CREATION, + ds->ds_phys->ds_creation_time); + dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_CREATETXG, + ds->ds_phys->ds_creation_txg); + dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_REFQUOTA, + ds->ds_quota); + dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_REFRESERVATION, + ds->ds_reserved); + dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_GUID, + ds->ds_phys->ds_guid); + dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_UNIQUE, + ds->ds_phys->ds_unique_bytes); + dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_OBJSETID, + ds->ds_object); + dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_USERREFS, + ds->ds_userrefs); + dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_DEFER_DESTROY, + DS_IS_DEFER_DESTROY(ds) ? 1 : 0); + + if (ds->ds_phys->ds_next_snap_obj) { + /* + * This is a snapshot; override the dd's space used with + * our unique space and compression ratio. + */ + dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_USED, + ds->ds_phys->ds_unique_bytes); + dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_COMPRESSRATIO, + ds->ds_phys->ds_compressed_bytes == 0 ? 100 : + (ds->ds_phys->ds_uncompressed_bytes * 100 / + ds->ds_phys->ds_compressed_bytes)); + } +} + +void +dsl_dataset_fast_stat(dsl_dataset_t *ds, dmu_objset_stats_t *stat) +{ + stat->dds_creation_txg = ds->ds_phys->ds_creation_txg; + stat->dds_inconsistent = ds->ds_phys->ds_flags & DS_FLAG_INCONSISTENT; + stat->dds_guid = ds->ds_phys->ds_guid; + if (ds->ds_phys->ds_next_snap_obj) { + stat->dds_is_snapshot = B_TRUE; + stat->dds_num_clones = ds->ds_phys->ds_num_children - 1; + } else { + stat->dds_is_snapshot = B_FALSE; + stat->dds_num_clones = 0; + } + + /* clone origin is really a dsl_dir thing... */ + rw_enter(&ds->ds_dir->dd_pool->dp_config_rwlock, RW_READER); + if (dsl_dir_is_clone(ds->ds_dir)) { + dsl_dataset_t *ods; + + VERIFY(0 == dsl_dataset_get_ref(ds->ds_dir->dd_pool, + ds->ds_dir->dd_phys->dd_origin_obj, FTAG, &ods)); + dsl_dataset_name(ods, stat->dds_origin); + dsl_dataset_drop_ref(ods, FTAG); + } else { + stat->dds_origin[0] = '\0'; + } + rw_exit(&ds->ds_dir->dd_pool->dp_config_rwlock); +} + +uint64_t +dsl_dataset_fsid_guid(dsl_dataset_t *ds) +{ + return (ds->ds_fsid_guid); +} + +void +dsl_dataset_space(dsl_dataset_t *ds, + uint64_t *refdbytesp, uint64_t *availbytesp, + uint64_t *usedobjsp, uint64_t *availobjsp) +{ + *refdbytesp = ds->ds_phys->ds_used_bytes; + *availbytesp = dsl_dir_space_available(ds->ds_dir, NULL, 0, TRUE); + if (ds->ds_reserved > ds->ds_phys->ds_unique_bytes) + *availbytesp += ds->ds_reserved - ds->ds_phys->ds_unique_bytes; + if (ds->ds_quota != 0) { + /* + * Adjust available bytes according to refquota + */ + if (*refdbytesp < ds->ds_quota) + *availbytesp = MIN(*availbytesp, + ds->ds_quota - *refdbytesp); + else + *availbytesp = 0; + } + *usedobjsp = ds->ds_phys->ds_bp.blk_fill; + *availobjsp = DN_MAX_OBJECT - *usedobjsp; +} + +boolean_t +dsl_dataset_modified_since_lastsnap(dsl_dataset_t *ds) +{ + dsl_pool_t *dp = ds->ds_dir->dd_pool; + + ASSERT(RW_LOCK_HELD(&dp->dp_config_rwlock) || + dsl_pool_sync_context(dp)); + if (ds->ds_prev == NULL) + return (B_FALSE); + if (ds->ds_phys->ds_bp.blk_birth > + ds->ds_prev->ds_phys->ds_creation_txg) { + objset_t *os, *os_prev; + /* + * It may be that only the ZIL differs, because it was + * reset in the head. Don't count that as being + * modified. + */ + if (dmu_objset_from_ds(ds, &os) != 0) + return (B_TRUE); + if (dmu_objset_from_ds(ds->ds_prev, &os_prev) != 0) + return (B_TRUE); + return (bcmp(&os->os_phys->os_meta_dnode, + &os_prev->os_phys->os_meta_dnode, + sizeof (os->os_phys->os_meta_dnode)) != 0); + } + return (B_FALSE); +} + +/* ARGSUSED */ +static int +dsl_dataset_snapshot_rename_check(void *arg1, void *arg2, dmu_tx_t *tx) +{ + dsl_dataset_t *ds = arg1; + char *newsnapname = arg2; + dsl_dir_t *dd = ds->ds_dir; + dsl_dataset_t *hds; + uint64_t val; + int err; + + err = dsl_dataset_hold_obj(dd->dd_pool, + dd->dd_phys->dd_head_dataset_obj, FTAG, &hds); + if (err) + return (err); + + /* new name better not be in use */ + err = dsl_dataset_snap_lookup(hds, newsnapname, &val); + dsl_dataset_rele(hds, FTAG); + + if (err == 0) + err = EEXIST; + else if (err == ENOENT) + err = 0; + + /* dataset name + 1 for the "@" + the new snapshot name must fit */ + if (dsl_dir_namelen(ds->ds_dir) + 1 + strlen(newsnapname) >= MAXNAMELEN) + err = ENAMETOOLONG; + + return (err); +} + +static void +dsl_dataset_snapshot_rename_sync(void *arg1, void *arg2, dmu_tx_t *tx) +{ + dsl_dataset_t *ds = arg1; + const char *newsnapname = arg2; + dsl_dir_t *dd = ds->ds_dir; + objset_t *mos = dd->dd_pool->dp_meta_objset; + dsl_dataset_t *hds; + int err; + + ASSERT(ds->ds_phys->ds_next_snap_obj != 0); + + VERIFY(0 == dsl_dataset_hold_obj(dd->dd_pool, + dd->dd_phys->dd_head_dataset_obj, FTAG, &hds)); + + VERIFY(0 == dsl_dataset_get_snapname(ds)); + err = dsl_dataset_snap_remove(hds, ds->ds_snapname, tx); + ASSERT3U(err, ==, 0); + mutex_enter(&ds->ds_lock); + (void) strcpy(ds->ds_snapname, newsnapname); + mutex_exit(&ds->ds_lock); + err = zap_add(mos, hds->ds_phys->ds_snapnames_zapobj, + ds->ds_snapname, 8, 1, &ds->ds_object, tx); + ASSERT3U(err, ==, 0); + + spa_history_log_internal(LOG_DS_RENAME, dd->dd_pool->dp_spa, tx, + "dataset = %llu", ds->ds_object); + dsl_dataset_rele(hds, FTAG); +} + +struct renamesnaparg { + dsl_sync_task_group_t *dstg; + char failed[MAXPATHLEN]; + char *oldsnap; + char *newsnap; +}; + +static int +dsl_snapshot_rename_one(const char *name, void *arg) +{ + struct renamesnaparg *ra = arg; + dsl_dataset_t *ds = NULL; + char *snapname; + int err; + + snapname = kmem_asprintf("%s@%s", name, ra->oldsnap); + (void) strlcpy(ra->failed, snapname, sizeof (ra->failed)); + + /* + * For recursive snapshot renames the parent won't be changing + * so we just pass name for both the to/from argument. + */ + err = zfs_secpolicy_rename_perms(snapname, snapname, CRED()); + if (err != 0) { + strfree(snapname); + return (err == ENOENT ? 0 : err); + } + +#ifdef _KERNEL + /* + * For all filesystems undergoing rename, we'll need to unmount it. + */ + (void) zfs_unmount_snap(snapname, NULL); +#endif + err = dsl_dataset_hold(snapname, ra->dstg, &ds); + strfree(snapname); + if (err != 0) + return (err == ENOENT ? 0 : err); + + dsl_sync_task_create(ra->dstg, dsl_dataset_snapshot_rename_check, + dsl_dataset_snapshot_rename_sync, ds, ra->newsnap, 0); + + return (0); +} + +static int +dsl_recursive_rename(char *oldname, const char *newname) +{ + int err; + struct renamesnaparg *ra; + dsl_sync_task_t *dst; + spa_t *spa; + char *cp, *fsname = spa_strdup(oldname); + int len = strlen(oldname) + 1; + + /* truncate the snapshot name to get the fsname */ + cp = strchr(fsname, '@'); + *cp = '\0'; + + err = spa_open(fsname, &spa, FTAG); + if (err) { + kmem_free(fsname, len); + return (err); + } + ra = kmem_alloc(sizeof (struct renamesnaparg), KM_SLEEP); + ra->dstg = dsl_sync_task_group_create(spa_get_dsl(spa)); + + ra->oldsnap = strchr(oldname, '@') + 1; + ra->newsnap = strchr(newname, '@') + 1; + *ra->failed = '\0'; + + err = dmu_objset_find(fsname, dsl_snapshot_rename_one, ra, + DS_FIND_CHILDREN); + kmem_free(fsname, len); + + if (err == 0) { + err = dsl_sync_task_group_wait(ra->dstg); + } + + for (dst = list_head(&ra->dstg->dstg_tasks); dst; + dst = list_next(&ra->dstg->dstg_tasks, dst)) { + dsl_dataset_t *ds = dst->dst_arg1; + if (dst->dst_err) { + dsl_dir_name(ds->ds_dir, ra->failed); + (void) strlcat(ra->failed, "@", sizeof (ra->failed)); + (void) strlcat(ra->failed, ra->newsnap, + sizeof (ra->failed)); + } + dsl_dataset_rele(ds, ra->dstg); + } + + if (err) + (void) strlcpy(oldname, ra->failed, sizeof (ra->failed)); + + dsl_sync_task_group_destroy(ra->dstg); + kmem_free(ra, sizeof (struct renamesnaparg)); + spa_close(spa, FTAG); + return (err); +} + +static int +dsl_valid_rename(const char *oldname, void *arg) +{ + int delta = *(int *)arg; + + if (strlen(oldname) + delta >= MAXNAMELEN) + return (ENAMETOOLONG); + + return (0); +} + +#pragma weak dmu_objset_rename = dsl_dataset_rename +int +dsl_dataset_rename(char *oldname, const char *newname, boolean_t recursive) +{ + dsl_dir_t *dd; + dsl_dataset_t *ds; + const char *tail; + int err; + + err = dsl_dir_open(oldname, FTAG, &dd, &tail); + if (err) + return (err); + + if (tail == NULL) { + int delta = strlen(newname) - strlen(oldname); + + /* if we're growing, validate child name lengths */ + if (delta > 0) + err = dmu_objset_find(oldname, dsl_valid_rename, + &delta, DS_FIND_CHILDREN | DS_FIND_SNAPSHOTS); + + if (err == 0) + err = dsl_dir_rename(dd, newname); + dsl_dir_close(dd, FTAG); + return (err); + } + + if (tail[0] != '@') { + /* the name ended in a nonexistent component */ + dsl_dir_close(dd, FTAG); + return (ENOENT); + } + + dsl_dir_close(dd, FTAG); + + /* new name must be snapshot in same filesystem */ + tail = strchr(newname, '@'); + if (tail == NULL) + return (EINVAL); + tail++; + if (strncmp(oldname, newname, tail - newname) != 0) + return (EXDEV); + + if (recursive) { + err = dsl_recursive_rename(oldname, newname); + } else { + err = dsl_dataset_hold(oldname, FTAG, &ds); + if (err) + return (err); + + err = dsl_sync_task_do(ds->ds_dir->dd_pool, + dsl_dataset_snapshot_rename_check, + dsl_dataset_snapshot_rename_sync, ds, (char *)tail, 1); + + dsl_dataset_rele(ds, FTAG); + } + + return (err); +} + +struct promotenode { + list_node_t link; + dsl_dataset_t *ds; +}; + +struct promotearg { + list_t shared_snaps, origin_snaps, clone_snaps; + dsl_dataset_t *origin_origin; + uint64_t used, comp, uncomp, unique, cloneusedsnap, originusedsnap; + char *err_ds; +}; + +static int snaplist_space(list_t *l, uint64_t mintxg, uint64_t *spacep); +static boolean_t snaplist_unstable(list_t *l); + +static int +dsl_dataset_promote_check(void *arg1, void *arg2, dmu_tx_t *tx) +{ + dsl_dataset_t *hds = arg1; + struct promotearg *pa = arg2; + struct promotenode *snap = list_head(&pa->shared_snaps); + dsl_dataset_t *origin_ds = snap->ds; + int err; + uint64_t unused; + + /* Check that it is a real clone */ + if (!dsl_dir_is_clone(hds->ds_dir)) + return (EINVAL); + + /* Since this is so expensive, don't do the preliminary check */ + if (!dmu_tx_is_syncing(tx)) + return (0); + + if (hds->ds_phys->ds_flags & DS_FLAG_NOPROMOTE) + return (EXDEV); + + /* compute origin's new unique space */ + snap = list_tail(&pa->clone_snaps); + ASSERT3U(snap->ds->ds_phys->ds_prev_snap_obj, ==, origin_ds->ds_object); + dsl_deadlist_space_range(&snap->ds->ds_deadlist, + origin_ds->ds_phys->ds_prev_snap_txg, UINT64_MAX, + &pa->unique, &unused, &unused); + + /* + * Walk the snapshots that we are moving + * + * Compute space to transfer. Consider the incremental changes + * to used for each snapshot: + * (my used) = (prev's used) + (blocks born) - (blocks killed) + * So each snapshot gave birth to: + * (blocks born) = (my used) - (prev's used) + (blocks killed) + * So a sequence would look like: + * (uN - u(N-1) + kN) + ... + (u1 - u0 + k1) + (u0 - 0 + k0) + * Which simplifies to: + * uN + kN + kN-1 + ... + k1 + k0 + * Note however, if we stop before we reach the ORIGIN we get: + * uN + kN + kN-1 + ... + kM - uM-1 + */ + pa->used = origin_ds->ds_phys->ds_used_bytes; + pa->comp = origin_ds->ds_phys->ds_compressed_bytes; + pa->uncomp = origin_ds->ds_phys->ds_uncompressed_bytes; + for (snap = list_head(&pa->shared_snaps); snap; + snap = list_next(&pa->shared_snaps, snap)) { + uint64_t val, dlused, dlcomp, dluncomp; + dsl_dataset_t *ds = snap->ds; + + /* Check that the snapshot name does not conflict */ + VERIFY(0 == dsl_dataset_get_snapname(ds)); + err = dsl_dataset_snap_lookup(hds, ds->ds_snapname, &val); + if (err == 0) { + err = EEXIST; + goto out; + } + if (err != ENOENT) + goto out; + + /* The very first snapshot does not have a deadlist */ + if (ds->ds_phys->ds_prev_snap_obj == 0) + continue; + + dsl_deadlist_space(&ds->ds_deadlist, + &dlused, &dlcomp, &dluncomp); + pa->used += dlused; + pa->comp += dlcomp; + pa->uncomp += dluncomp; + } + + /* + * If we are a clone of a clone then we never reached ORIGIN, + * so we need to subtract out the clone origin's used space. + */ + if (pa->origin_origin) { + pa->used -= pa->origin_origin->ds_phys->ds_used_bytes; + pa->comp -= pa->origin_origin->ds_phys->ds_compressed_bytes; + pa->uncomp -= pa->origin_origin->ds_phys->ds_uncompressed_bytes; + } + + /* Check that there is enough space here */ + err = dsl_dir_transfer_possible(origin_ds->ds_dir, hds->ds_dir, + pa->used); + if (err) + return (err); + + /* + * Compute the amounts of space that will be used by snapshots + * after the promotion (for both origin and clone). For each, + * it is the amount of space that will be on all of their + * deadlists (that was not born before their new origin). + */ + if (hds->ds_dir->dd_phys->dd_flags & DD_FLAG_USED_BREAKDOWN) { + uint64_t space; + + /* + * Note, typically this will not be a clone of a clone, + * so dd_origin_txg will be < TXG_INITIAL, so + * these snaplist_space() -> dsl_deadlist_space_range() + * calls will be fast because they do not have to + * iterate over all bps. + */ + snap = list_head(&pa->origin_snaps); + err = snaplist_space(&pa->shared_snaps, + snap->ds->ds_dir->dd_origin_txg, &pa->cloneusedsnap); + if (err) + return (err); + + err = snaplist_space(&pa->clone_snaps, + snap->ds->ds_dir->dd_origin_txg, &space); + if (err) + return (err); + pa->cloneusedsnap += space; + } + if (origin_ds->ds_dir->dd_phys->dd_flags & DD_FLAG_USED_BREAKDOWN) { + err = snaplist_space(&pa->origin_snaps, + origin_ds->ds_phys->ds_creation_txg, &pa->originusedsnap); + if (err) + return (err); + } + + return (0); +out: + pa->err_ds = snap->ds->ds_snapname; + return (err); +} + +static void +dsl_dataset_promote_sync(void *arg1, void *arg2, dmu_tx_t *tx) +{ + dsl_dataset_t *hds = arg1; + struct promotearg *pa = arg2; + struct promotenode *snap = list_head(&pa->shared_snaps); + dsl_dataset_t *origin_ds = snap->ds; + dsl_dataset_t *origin_head; + dsl_dir_t *dd = hds->ds_dir; + dsl_pool_t *dp = hds->ds_dir->dd_pool; + dsl_dir_t *odd = NULL; + uint64_t oldnext_obj; + int64_t delta; + + ASSERT(0 == (hds->ds_phys->ds_flags & DS_FLAG_NOPROMOTE)); + + snap = list_head(&pa->origin_snaps); + origin_head = snap->ds; + + /* + * We need to explicitly open odd, since origin_ds's dd will be + * changing. + */ + VERIFY(0 == dsl_dir_open_obj(dp, origin_ds->ds_dir->dd_object, + NULL, FTAG, &odd)); + + /* change origin's next snap */ + dmu_buf_will_dirty(origin_ds->ds_dbuf, tx); + oldnext_obj = origin_ds->ds_phys->ds_next_snap_obj; + snap = list_tail(&pa->clone_snaps); + ASSERT3U(snap->ds->ds_phys->ds_prev_snap_obj, ==, origin_ds->ds_object); + origin_ds->ds_phys->ds_next_snap_obj = snap->ds->ds_object; + + /* change the origin's next clone */ + if (origin_ds->ds_phys->ds_next_clones_obj) { + remove_from_next_clones(origin_ds, snap->ds->ds_object, tx); + VERIFY3U(0, ==, zap_add_int(dp->dp_meta_objset, + origin_ds->ds_phys->ds_next_clones_obj, + oldnext_obj, tx)); + } + + /* change origin */ + dmu_buf_will_dirty(dd->dd_dbuf, tx); + ASSERT3U(dd->dd_phys->dd_origin_obj, ==, origin_ds->ds_object); + dd->dd_phys->dd_origin_obj = odd->dd_phys->dd_origin_obj; + dd->dd_origin_txg = origin_head->ds_dir->dd_origin_txg; + dmu_buf_will_dirty(odd->dd_dbuf, tx); + odd->dd_phys->dd_origin_obj = origin_ds->ds_object; + origin_head->ds_dir->dd_origin_txg = + origin_ds->ds_phys->ds_creation_txg; + + /* change dd_clone entries */ + if (spa_version(dp->dp_spa) >= SPA_VERSION_DIR_CLONES) { + VERIFY3U(0, ==, zap_remove_int(dp->dp_meta_objset, + odd->dd_phys->dd_clones, hds->ds_object, tx)); + VERIFY3U(0, ==, zap_add_int(dp->dp_meta_objset, + pa->origin_origin->ds_dir->dd_phys->dd_clones, + hds->ds_object, tx)); + + VERIFY3U(0, ==, zap_remove_int(dp->dp_meta_objset, + pa->origin_origin->ds_dir->dd_phys->dd_clones, + origin_head->ds_object, tx)); + if (dd->dd_phys->dd_clones == 0) { + dd->dd_phys->dd_clones = zap_create(dp->dp_meta_objset, + DMU_OT_DSL_CLONES, DMU_OT_NONE, 0, tx); + } + VERIFY3U(0, ==, zap_add_int(dp->dp_meta_objset, + dd->dd_phys->dd_clones, origin_head->ds_object, tx)); + + } + + /* move snapshots to this dir */ + for (snap = list_head(&pa->shared_snaps); snap; + snap = list_next(&pa->shared_snaps, snap)) { + dsl_dataset_t *ds = snap->ds; + + /* unregister props as dsl_dir is changing */ + if (ds->ds_objset) { + dmu_objset_evict(ds->ds_objset); + ds->ds_objset = NULL; + } + /* move snap name entry */ + VERIFY(0 == dsl_dataset_get_snapname(ds)); + VERIFY(0 == dsl_dataset_snap_remove(origin_head, + ds->ds_snapname, tx)); + VERIFY(0 == zap_add(dp->dp_meta_objset, + hds->ds_phys->ds_snapnames_zapobj, ds->ds_snapname, + 8, 1, &ds->ds_object, tx)); + + /* change containing dsl_dir */ + dmu_buf_will_dirty(ds->ds_dbuf, tx); + ASSERT3U(ds->ds_phys->ds_dir_obj, ==, odd->dd_object); + ds->ds_phys->ds_dir_obj = dd->dd_object; + ASSERT3P(ds->ds_dir, ==, odd); + dsl_dir_close(ds->ds_dir, ds); + VERIFY(0 == dsl_dir_open_obj(dp, dd->dd_object, + NULL, ds, &ds->ds_dir)); + + /* move any clone references */ + if (ds->ds_phys->ds_next_clones_obj && + spa_version(dp->dp_spa) >= SPA_VERSION_DIR_CLONES) { + zap_cursor_t zc; + zap_attribute_t za; + + for (zap_cursor_init(&zc, dp->dp_meta_objset, + ds->ds_phys->ds_next_clones_obj); + zap_cursor_retrieve(&zc, &za) == 0; + zap_cursor_advance(&zc)) { + dsl_dataset_t *cnds; + uint64_t o; + + if (za.za_first_integer == oldnext_obj) { + /* + * We've already moved the + * origin's reference. + */ + continue; + } + + VERIFY3U(0, ==, dsl_dataset_hold_obj(dp, + za.za_first_integer, FTAG, &cnds)); + o = cnds->ds_dir->dd_phys->dd_head_dataset_obj; + + VERIFY3U(zap_remove_int(dp->dp_meta_objset, + odd->dd_phys->dd_clones, o, tx), ==, 0); + VERIFY3U(zap_add_int(dp->dp_meta_objset, + dd->dd_phys->dd_clones, o, tx), ==, 0); + dsl_dataset_rele(cnds, FTAG); + } + zap_cursor_fini(&zc); + } + + ASSERT3U(dsl_prop_numcb(ds), ==, 0); + } + + /* + * Change space accounting. + * Note, pa->*usedsnap and dd_used_breakdown[SNAP] will either + * both be valid, or both be 0 (resulting in delta == 0). This + * is true for each of {clone,origin} independently. + */ + + delta = pa->cloneusedsnap - + dd->dd_phys->dd_used_breakdown[DD_USED_SNAP]; + ASSERT3S(delta, >=, 0); + ASSERT3U(pa->used, >=, delta); + dsl_dir_diduse_space(dd, DD_USED_SNAP, delta, 0, 0, tx); + dsl_dir_diduse_space(dd, DD_USED_HEAD, + pa->used - delta, pa->comp, pa->uncomp, tx); + + delta = pa->originusedsnap - + odd->dd_phys->dd_used_breakdown[DD_USED_SNAP]; + ASSERT3S(delta, <=, 0); + ASSERT3U(pa->used, >=, -delta); + dsl_dir_diduse_space(odd, DD_USED_SNAP, delta, 0, 0, tx); + dsl_dir_diduse_space(odd, DD_USED_HEAD, + -pa->used - delta, -pa->comp, -pa->uncomp, tx); + + origin_ds->ds_phys->ds_unique_bytes = pa->unique; + + /* log history record */ + spa_history_log_internal(LOG_DS_PROMOTE, dd->dd_pool->dp_spa, tx, + "dataset = %llu", hds->ds_object); + + dsl_dir_close(odd, FTAG); +} + +static char *snaplist_tag = "snaplist"; +/* + * Make a list of dsl_dataset_t's for the snapshots between first_obj + * (exclusive) and last_obj (inclusive). The list will be in reverse + * order (last_obj will be the list_head()). If first_obj == 0, do all + * snapshots back to this dataset's origin. + */ +static int +snaplist_make(dsl_pool_t *dp, boolean_t own, + uint64_t first_obj, uint64_t last_obj, list_t *l) +{ + uint64_t obj = last_obj; + + ASSERT(RW_LOCK_HELD(&dp->dp_config_rwlock)); + + list_create(l, sizeof (struct promotenode), + offsetof(struct promotenode, link)); + + while (obj != first_obj) { + dsl_dataset_t *ds; + struct promotenode *snap; + int err; + + if (own) { + err = dsl_dataset_own_obj(dp, obj, + 0, snaplist_tag, &ds); + if (err == 0) + dsl_dataset_make_exclusive(ds, snaplist_tag); + } else { + err = dsl_dataset_hold_obj(dp, obj, snaplist_tag, &ds); + } + if (err == ENOENT) { + /* lost race with snapshot destroy */ + struct promotenode *last = list_tail(l); + ASSERT(obj != last->ds->ds_phys->ds_prev_snap_obj); + obj = last->ds->ds_phys->ds_prev_snap_obj; + continue; + } else if (err) { + return (err); + } + + if (first_obj == 0) + first_obj = ds->ds_dir->dd_phys->dd_origin_obj; + + snap = kmem_alloc(sizeof (struct promotenode), KM_SLEEP); + snap->ds = ds; + list_insert_tail(l, snap); + obj = ds->ds_phys->ds_prev_snap_obj; + } + + return (0); +} + +static int +snaplist_space(list_t *l, uint64_t mintxg, uint64_t *spacep) +{ + struct promotenode *snap; + + *spacep = 0; + for (snap = list_head(l); snap; snap = list_next(l, snap)) { + uint64_t used, comp, uncomp; + dsl_deadlist_space_range(&snap->ds->ds_deadlist, + mintxg, UINT64_MAX, &used, &comp, &uncomp); + *spacep += used; + } + return (0); +} + +static void +snaplist_destroy(list_t *l, boolean_t own) +{ + struct promotenode *snap; + + if (!l || !list_link_active(&l->list_head)) + return; + + while ((snap = list_tail(l)) != NULL) { + list_remove(l, snap); + if (own) + dsl_dataset_disown(snap->ds, snaplist_tag); + else + dsl_dataset_rele(snap->ds, snaplist_tag); + kmem_free(snap, sizeof (struct promotenode)); + } + list_destroy(l); +} + +/* + * Promote a clone. Nomenclature note: + * "clone" or "cds": the original clone which is being promoted + * "origin" or "ods": the snapshot which is originally clone's origin + * "origin head" or "ohds": the dataset which is the head + * (filesystem/volume) for the origin + * "origin origin": the origin of the origin's filesystem (typically + * NULL, indicating that the clone is not a clone of a clone). + */ +int +dsl_dataset_promote(const char *name, char *conflsnap) +{ + dsl_dataset_t *ds; + dsl_dir_t *dd; + dsl_pool_t *dp; + dmu_object_info_t doi; + struct promotearg pa = { 0 }; + struct promotenode *snap; + int err; + + err = dsl_dataset_hold(name, FTAG, &ds); + if (err) + return (err); + dd = ds->ds_dir; + dp = dd->dd_pool; + + err = dmu_object_info(dp->dp_meta_objset, + ds->ds_phys->ds_snapnames_zapobj, &doi); + if (err) { + dsl_dataset_rele(ds, FTAG); + return (err); + } + + if (dsl_dataset_is_snapshot(ds) || dd->dd_phys->dd_origin_obj == 0) { + dsl_dataset_rele(ds, FTAG); + return (EINVAL); + } + + /* + * We are going to inherit all the snapshots taken before our + * origin (i.e., our new origin will be our parent's origin). + * Take ownership of them so that we can rename them into our + * namespace. + */ + rw_enter(&dp->dp_config_rwlock, RW_READER); + + err = snaplist_make(dp, B_TRUE, 0, dd->dd_phys->dd_origin_obj, + &pa.shared_snaps); + if (err != 0) + goto out; + + err = snaplist_make(dp, B_FALSE, 0, ds->ds_object, &pa.clone_snaps); + if (err != 0) + goto out; + + snap = list_head(&pa.shared_snaps); + ASSERT3U(snap->ds->ds_object, ==, dd->dd_phys->dd_origin_obj); + err = snaplist_make(dp, B_FALSE, dd->dd_phys->dd_origin_obj, + snap->ds->ds_dir->dd_phys->dd_head_dataset_obj, &pa.origin_snaps); + if (err != 0) + goto out; + + if (snap->ds->ds_dir->dd_phys->dd_origin_obj != 0) { + err = dsl_dataset_hold_obj(dp, + snap->ds->ds_dir->dd_phys->dd_origin_obj, + FTAG, &pa.origin_origin); + if (err != 0) + goto out; + } + +out: + rw_exit(&dp->dp_config_rwlock); + + /* + * Add in 128x the snapnames zapobj size, since we will be moving + * a bunch of snapnames to the promoted ds, and dirtying their + * bonus buffers. + */ + if (err == 0) { + err = dsl_sync_task_do(dp, dsl_dataset_promote_check, + dsl_dataset_promote_sync, ds, &pa, + 2 + 2 * doi.doi_physical_blocks_512); + if (err && pa.err_ds && conflsnap) + (void) strncpy(conflsnap, pa.err_ds, MAXNAMELEN); + } + + snaplist_destroy(&pa.shared_snaps, B_TRUE); + snaplist_destroy(&pa.clone_snaps, B_FALSE); + snaplist_destroy(&pa.origin_snaps, B_FALSE); + if (pa.origin_origin) + dsl_dataset_rele(pa.origin_origin, FTAG); + dsl_dataset_rele(ds, FTAG); + return (err); +} + +struct cloneswaparg { + dsl_dataset_t *cds; /* clone dataset */ + dsl_dataset_t *ohds; /* origin's head dataset */ + boolean_t force; + int64_t unused_refres_delta; /* change in unconsumed refreservation */ +}; + +/* ARGSUSED */ +static int +dsl_dataset_clone_swap_check(void *arg1, void *arg2, dmu_tx_t *tx) +{ + struct cloneswaparg *csa = arg1; + + /* they should both be heads */ + if (dsl_dataset_is_snapshot(csa->cds) || + dsl_dataset_is_snapshot(csa->ohds)) + return (EINVAL); + + /* the branch point should be just before them */ + if (csa->cds->ds_prev != csa->ohds->ds_prev) + return (EINVAL); + + /* cds should be the clone (unless they are unrelated) */ + if (csa->cds->ds_prev != NULL && + csa->cds->ds_prev != csa->cds->ds_dir->dd_pool->dp_origin_snap && + csa->ohds->ds_object != + csa->cds->ds_prev->ds_phys->ds_next_snap_obj) + return (EINVAL); + + /* the clone should be a child of the origin */ + if (csa->cds->ds_dir->dd_parent != csa->ohds->ds_dir) + return (EINVAL); + + /* ohds shouldn't be modified unless 'force' */ + if (!csa->force && dsl_dataset_modified_since_lastsnap(csa->ohds)) + return (ETXTBSY); + + /* adjust amount of any unconsumed refreservation */ + csa->unused_refres_delta = + (int64_t)MIN(csa->ohds->ds_reserved, + csa->ohds->ds_phys->ds_unique_bytes) - + (int64_t)MIN(csa->ohds->ds_reserved, + csa->cds->ds_phys->ds_unique_bytes); + + if (csa->unused_refres_delta > 0 && + csa->unused_refres_delta > + dsl_dir_space_available(csa->ohds->ds_dir, NULL, 0, TRUE)) + return (ENOSPC); + + if (csa->ohds->ds_quota != 0 && + csa->cds->ds_phys->ds_unique_bytes > csa->ohds->ds_quota) + return (EDQUOT); + + return (0); +} + +/* ARGSUSED */ +static void +dsl_dataset_clone_swap_sync(void *arg1, void *arg2, dmu_tx_t *tx) +{ + struct cloneswaparg *csa = arg1; + dsl_pool_t *dp = csa->cds->ds_dir->dd_pool; + + ASSERT(csa->cds->ds_reserved == 0); + ASSERT(csa->ohds->ds_quota == 0 || + csa->cds->ds_phys->ds_unique_bytes <= csa->ohds->ds_quota); + + dmu_buf_will_dirty(csa->cds->ds_dbuf, tx); + dmu_buf_will_dirty(csa->ohds->ds_dbuf, tx); + + if (csa->cds->ds_objset != NULL) { + dmu_objset_evict(csa->cds->ds_objset); + csa->cds->ds_objset = NULL; + } + + if (csa->ohds->ds_objset != NULL) { + dmu_objset_evict(csa->ohds->ds_objset); + csa->ohds->ds_objset = NULL; + } + + /* + * Reset origin's unique bytes, if it exists. + */ + if (csa->cds->ds_prev) { + dsl_dataset_t *origin = csa->cds->ds_prev; + uint64_t comp, uncomp; + + dmu_buf_will_dirty(origin->ds_dbuf, tx); + dsl_deadlist_space_range(&csa->cds->ds_deadlist, + origin->ds_phys->ds_prev_snap_txg, UINT64_MAX, + &origin->ds_phys->ds_unique_bytes, &comp, &uncomp); + } + + /* swap blkptrs */ + { + blkptr_t tmp; + tmp = csa->ohds->ds_phys->ds_bp; + csa->ohds->ds_phys->ds_bp = csa->cds->ds_phys->ds_bp; + csa->cds->ds_phys->ds_bp = tmp; + } + + /* set dd_*_bytes */ + { + int64_t dused, dcomp, duncomp; + uint64_t cdl_used, cdl_comp, cdl_uncomp; + uint64_t odl_used, odl_comp, odl_uncomp; + + ASSERT3U(csa->cds->ds_dir->dd_phys-> + dd_used_breakdown[DD_USED_SNAP], ==, 0); + + dsl_deadlist_space(&csa->cds->ds_deadlist, + &cdl_used, &cdl_comp, &cdl_uncomp); + dsl_deadlist_space(&csa->ohds->ds_deadlist, + &odl_used, &odl_comp, &odl_uncomp); + + dused = csa->cds->ds_phys->ds_used_bytes + cdl_used - + (csa->ohds->ds_phys->ds_used_bytes + odl_used); + dcomp = csa->cds->ds_phys->ds_compressed_bytes + cdl_comp - + (csa->ohds->ds_phys->ds_compressed_bytes + odl_comp); + duncomp = csa->cds->ds_phys->ds_uncompressed_bytes + + cdl_uncomp - + (csa->ohds->ds_phys->ds_uncompressed_bytes + odl_uncomp); + + dsl_dir_diduse_space(csa->ohds->ds_dir, DD_USED_HEAD, + dused, dcomp, duncomp, tx); + dsl_dir_diduse_space(csa->cds->ds_dir, DD_USED_HEAD, + -dused, -dcomp, -duncomp, tx); + + /* + * The difference in the space used by snapshots is the + * difference in snapshot space due to the head's + * deadlist (since that's the only thing that's + * changing that affects the snapused). + */ + dsl_deadlist_space_range(&csa->cds->ds_deadlist, + csa->ohds->ds_dir->dd_origin_txg, UINT64_MAX, + &cdl_used, &cdl_comp, &cdl_uncomp); + dsl_deadlist_space_range(&csa->ohds->ds_deadlist, + csa->ohds->ds_dir->dd_origin_txg, UINT64_MAX, + &odl_used, &odl_comp, &odl_uncomp); + dsl_dir_transfer_space(csa->ohds->ds_dir, cdl_used - odl_used, + DD_USED_HEAD, DD_USED_SNAP, tx); + } + + /* swap ds_*_bytes */ + SWITCH64(csa->ohds->ds_phys->ds_used_bytes, + csa->cds->ds_phys->ds_used_bytes); + SWITCH64(csa->ohds->ds_phys->ds_compressed_bytes, + csa->cds->ds_phys->ds_compressed_bytes); + SWITCH64(csa->ohds->ds_phys->ds_uncompressed_bytes, + csa->cds->ds_phys->ds_uncompressed_bytes); + SWITCH64(csa->ohds->ds_phys->ds_unique_bytes, + csa->cds->ds_phys->ds_unique_bytes); + + /* apply any parent delta for change in unconsumed refreservation */ + dsl_dir_diduse_space(csa->ohds->ds_dir, DD_USED_REFRSRV, + csa->unused_refres_delta, 0, 0, tx); + + /* + * Swap deadlists. + */ + dsl_deadlist_close(&csa->cds->ds_deadlist); + dsl_deadlist_close(&csa->ohds->ds_deadlist); + SWITCH64(csa->ohds->ds_phys->ds_deadlist_obj, + csa->cds->ds_phys->ds_deadlist_obj); + dsl_deadlist_open(&csa->cds->ds_deadlist, dp->dp_meta_objset, + csa->cds->ds_phys->ds_deadlist_obj); + dsl_deadlist_open(&csa->ohds->ds_deadlist, dp->dp_meta_objset, + csa->ohds->ds_phys->ds_deadlist_obj); + + dsl_scan_ds_clone_swapped(csa->ohds, csa->cds, tx); +} + +/* + * Swap 'clone' with its origin head datasets. Used at the end of "zfs + * recv" into an existing fs to swizzle the file system to the new + * version, and by "zfs rollback". Can also be used to swap two + * independent head datasets if neither has any snapshots. + */ +int +dsl_dataset_clone_swap(dsl_dataset_t *clone, dsl_dataset_t *origin_head, + boolean_t force) +{ + struct cloneswaparg csa; + int error; + + ASSERT(clone->ds_owner); + ASSERT(origin_head->ds_owner); +retry: + /* + * Need exclusive access for the swap. If we're swapping these + * datasets back after an error, we already hold the locks. + */ + if (!RW_WRITE_HELD(&clone->ds_rwlock)) + rw_enter(&clone->ds_rwlock, RW_WRITER); + if (!RW_WRITE_HELD(&origin_head->ds_rwlock) && + !rw_tryenter(&origin_head->ds_rwlock, RW_WRITER)) { + rw_exit(&clone->ds_rwlock); + rw_enter(&origin_head->ds_rwlock, RW_WRITER); + if (!rw_tryenter(&clone->ds_rwlock, RW_WRITER)) { + rw_exit(&origin_head->ds_rwlock); + goto retry; + } + } + csa.cds = clone; + csa.ohds = origin_head; + csa.force = force; + error = dsl_sync_task_do(clone->ds_dir->dd_pool, + dsl_dataset_clone_swap_check, + dsl_dataset_clone_swap_sync, &csa, NULL, 9); + return (error); +} + +/* + * Given a pool name and a dataset object number in that pool, + * return the name of that dataset. + */ +int +dsl_dsobj_to_dsname(char *pname, uint64_t obj, char *buf) +{ + spa_t *spa; + dsl_pool_t *dp; + dsl_dataset_t *ds; + int error; + + if ((error = spa_open(pname, &spa, FTAG)) != 0) + return (error); + dp = spa_get_dsl(spa); + rw_enter(&dp->dp_config_rwlock, RW_READER); + if ((error = dsl_dataset_hold_obj(dp, obj, FTAG, &ds)) == 0) { + dsl_dataset_name(ds, buf); + dsl_dataset_rele(ds, FTAG); + } + rw_exit(&dp->dp_config_rwlock); + spa_close(spa, FTAG); + + return (error); +} + +int +dsl_dataset_check_quota(dsl_dataset_t *ds, boolean_t check_quota, + uint64_t asize, uint64_t inflight, uint64_t *used, uint64_t *ref_rsrv) +{ + int error = 0; + + ASSERT3S(asize, >, 0); + + /* + * *ref_rsrv is the portion of asize that will come from any + * unconsumed refreservation space. + */ + *ref_rsrv = 0; + + mutex_enter(&ds->ds_lock); + /* + * Make a space adjustment for reserved bytes. + */ + if (ds->ds_reserved > ds->ds_phys->ds_unique_bytes) { + ASSERT3U(*used, >=, + ds->ds_reserved - ds->ds_phys->ds_unique_bytes); + *used -= (ds->ds_reserved - ds->ds_phys->ds_unique_bytes); + *ref_rsrv = + asize - MIN(asize, parent_delta(ds, asize + inflight)); + } + + if (!check_quota || ds->ds_quota == 0) { + mutex_exit(&ds->ds_lock); + return (0); + } + /* + * If they are requesting more space, and our current estimate + * is over quota, they get to try again unless the actual + * on-disk is over quota and there are no pending changes (which + * may free up space for us). + */ + if (ds->ds_phys->ds_used_bytes + inflight >= ds->ds_quota) { + if (inflight > 0 || ds->ds_phys->ds_used_bytes < ds->ds_quota) + error = ERESTART; + else + error = EDQUOT; + } + mutex_exit(&ds->ds_lock); + + return (error); +} + +/* ARGSUSED */ +static int +dsl_dataset_set_quota_check(void *arg1, void *arg2, dmu_tx_t *tx) +{ + dsl_dataset_t *ds = arg1; + dsl_prop_setarg_t *psa = arg2; + int err; + + if (spa_version(ds->ds_dir->dd_pool->dp_spa) < SPA_VERSION_REFQUOTA) + return (ENOTSUP); + + if ((err = dsl_prop_predict_sync(ds->ds_dir, psa)) != 0) + return (err); + + if (psa->psa_effective_value == 0) + return (0); + + if (psa->psa_effective_value < ds->ds_phys->ds_used_bytes || + psa->psa_effective_value < ds->ds_reserved) + return (ENOSPC); + + return (0); +} + +extern void dsl_prop_set_sync(void *, void *, dmu_tx_t *); + +void +dsl_dataset_set_quota_sync(void *arg1, void *arg2, dmu_tx_t *tx) +{ + dsl_dataset_t *ds = arg1; + dsl_prop_setarg_t *psa = arg2; + uint64_t effective_value = psa->psa_effective_value; + + dsl_prop_set_sync(ds, psa, tx); + DSL_PROP_CHECK_PREDICTION(ds->ds_dir, psa); + + if (ds->ds_quota != effective_value) { + dmu_buf_will_dirty(ds->ds_dbuf, tx); + ds->ds_quota = effective_value; + + spa_history_log_internal(LOG_DS_REFQUOTA, + ds->ds_dir->dd_pool->dp_spa, tx, "%lld dataset = %llu ", + (longlong_t)ds->ds_quota, ds->ds_object); + } +} + +int +dsl_dataset_set_quota(const char *dsname, zprop_source_t source, uint64_t quota) +{ + dsl_dataset_t *ds; + dsl_prop_setarg_t psa; + int err; + + dsl_prop_setarg_init_uint64(&psa, "refquota", source, "a); + + err = dsl_dataset_hold(dsname, FTAG, &ds); + if (err) + return (err); + + /* + * If someone removes a file, then tries to set the quota, we + * want to make sure the file freeing takes effect. + */ + txg_wait_open(ds->ds_dir->dd_pool, 0); + + err = dsl_sync_task_do(ds->ds_dir->dd_pool, + dsl_dataset_set_quota_check, dsl_dataset_set_quota_sync, + ds, &psa, 0); + + dsl_dataset_rele(ds, FTAG); + return (err); +} + +static int +dsl_dataset_set_reservation_check(void *arg1, void *arg2, dmu_tx_t *tx) +{ + dsl_dataset_t *ds = arg1; + dsl_prop_setarg_t *psa = arg2; + uint64_t effective_value; + uint64_t unique; + int err; + + if (spa_version(ds->ds_dir->dd_pool->dp_spa) < + SPA_VERSION_REFRESERVATION) + return (ENOTSUP); + + if (dsl_dataset_is_snapshot(ds)) + return (EINVAL); + + if ((err = dsl_prop_predict_sync(ds->ds_dir, psa)) != 0) + return (err); + + effective_value = psa->psa_effective_value; + + /* + * If we are doing the preliminary check in open context, the + * space estimates may be inaccurate. + */ + if (!dmu_tx_is_syncing(tx)) + return (0); + + mutex_enter(&ds->ds_lock); + if (!DS_UNIQUE_IS_ACCURATE(ds)) + dsl_dataset_recalc_head_uniq(ds); + unique = ds->ds_phys->ds_unique_bytes; + mutex_exit(&ds->ds_lock); + + if (MAX(unique, effective_value) > MAX(unique, ds->ds_reserved)) { + uint64_t delta = MAX(unique, effective_value) - + MAX(unique, ds->ds_reserved); + + if (delta > dsl_dir_space_available(ds->ds_dir, NULL, 0, TRUE)) + return (ENOSPC); + if (ds->ds_quota > 0 && + effective_value > ds->ds_quota) + return (ENOSPC); + } + + return (0); +} + +static void +dsl_dataset_set_reservation_sync(void *arg1, void *arg2, dmu_tx_t *tx) +{ + dsl_dataset_t *ds = arg1; + dsl_prop_setarg_t *psa = arg2; + uint64_t effective_value = psa->psa_effective_value; + uint64_t unique; + int64_t delta; + + dsl_prop_set_sync(ds, psa, tx); + DSL_PROP_CHECK_PREDICTION(ds->ds_dir, psa); + + dmu_buf_will_dirty(ds->ds_dbuf, tx); + + mutex_enter(&ds->ds_dir->dd_lock); + mutex_enter(&ds->ds_lock); + ASSERT(DS_UNIQUE_IS_ACCURATE(ds)); + unique = ds->ds_phys->ds_unique_bytes; + delta = MAX(0, (int64_t)(effective_value - unique)) - + MAX(0, (int64_t)(ds->ds_reserved - unique)); + ds->ds_reserved = effective_value; + mutex_exit(&ds->ds_lock); + + dsl_dir_diduse_space(ds->ds_dir, DD_USED_REFRSRV, delta, 0, 0, tx); + mutex_exit(&ds->ds_dir->dd_lock); + + spa_history_log_internal(LOG_DS_REFRESERV, + ds->ds_dir->dd_pool->dp_spa, tx, "%lld dataset = %llu", + (longlong_t)effective_value, ds->ds_object); +} + +int +dsl_dataset_set_reservation(const char *dsname, zprop_source_t source, + uint64_t reservation) +{ + dsl_dataset_t *ds; + dsl_prop_setarg_t psa; + int err; + + dsl_prop_setarg_init_uint64(&psa, "refreservation", source, + &reservation); + + err = dsl_dataset_hold(dsname, FTAG, &ds); + if (err) + return (err); + + err = dsl_sync_task_do(ds->ds_dir->dd_pool, + dsl_dataset_set_reservation_check, + dsl_dataset_set_reservation_sync, ds, &psa, 0); + + dsl_dataset_rele(ds, FTAG); + return (err); +} + +typedef struct zfs_hold_cleanup_arg { + dsl_pool_t *dp; + uint64_t dsobj; + char htag[MAXNAMELEN]; +} zfs_hold_cleanup_arg_t; + +static void +dsl_dataset_user_release_onexit(void *arg) +{ + zfs_hold_cleanup_arg_t *ca = arg; + + (void) dsl_dataset_user_release_tmp(ca->dp, ca->dsobj, ca->htag, + B_TRUE); + kmem_free(ca, sizeof (zfs_hold_cleanup_arg_t)); +} + +void +dsl_register_onexit_hold_cleanup(dsl_dataset_t *ds, const char *htag, + minor_t minor) +{ + zfs_hold_cleanup_arg_t *ca; + + ca = kmem_alloc(sizeof (zfs_hold_cleanup_arg_t), KM_SLEEP); + ca->dp = ds->ds_dir->dd_pool; + ca->dsobj = ds->ds_object; + (void) strlcpy(ca->htag, htag, sizeof (ca->htag)); + VERIFY3U(0, ==, zfs_onexit_add_cb(minor, + dsl_dataset_user_release_onexit, ca, NULL)); +} + +/* + * If you add new checks here, you may need to add + * additional checks to the "temporary" case in + * snapshot_check() in dmu_objset.c. + */ +static int +dsl_dataset_user_hold_check(void *arg1, void *arg2, dmu_tx_t *tx) +{ + dsl_dataset_t *ds = arg1; + struct dsl_ds_holdarg *ha = arg2; + char *htag = ha->htag; + objset_t *mos = ds->ds_dir->dd_pool->dp_meta_objset; + int error = 0; + + if (spa_version(ds->ds_dir->dd_pool->dp_spa) < SPA_VERSION_USERREFS) + return (ENOTSUP); + + if (!dsl_dataset_is_snapshot(ds)) + return (EINVAL); + + /* tags must be unique */ + mutex_enter(&ds->ds_lock); + if (ds->ds_phys->ds_userrefs_obj) { + error = zap_lookup(mos, ds->ds_phys->ds_userrefs_obj, htag, + 8, 1, tx); + if (error == 0) + error = EEXIST; + else if (error == ENOENT) + error = 0; + } + mutex_exit(&ds->ds_lock); + + if (error == 0 && ha->temphold && + strlen(htag) + MAX_TAG_PREFIX_LEN >= MAXNAMELEN) + error = E2BIG; + + return (error); +} + +void +dsl_dataset_user_hold_sync(void *arg1, void *arg2, dmu_tx_t *tx) +{ + dsl_dataset_t *ds = arg1; + struct dsl_ds_holdarg *ha = arg2; + char *htag = ha->htag; + dsl_pool_t *dp = ds->ds_dir->dd_pool; + objset_t *mos = dp->dp_meta_objset; + uint64_t now = gethrestime_sec(); + uint64_t zapobj; + + mutex_enter(&ds->ds_lock); + if (ds->ds_phys->ds_userrefs_obj == 0) { + /* + * This is the first user hold for this dataset. Create + * the userrefs zap object. + */ + dmu_buf_will_dirty(ds->ds_dbuf, tx); + zapobj = ds->ds_phys->ds_userrefs_obj = + zap_create(mos, DMU_OT_USERREFS, DMU_OT_NONE, 0, tx); + } else { + zapobj = ds->ds_phys->ds_userrefs_obj; + } + ds->ds_userrefs++; + mutex_exit(&ds->ds_lock); + + VERIFY(0 == zap_add(mos, zapobj, htag, 8, 1, &now, tx)); + + if (ha->temphold) { + VERIFY(0 == dsl_pool_user_hold(dp, ds->ds_object, + htag, &now, tx)); + } + + spa_history_log_internal(LOG_DS_USER_HOLD, + dp->dp_spa, tx, "<%s> temp = %d dataset = %llu", htag, + (int)ha->temphold, ds->ds_object); +} + +static int +dsl_dataset_user_hold_one(const char *dsname, void *arg) +{ + struct dsl_ds_holdarg *ha = arg; + dsl_dataset_t *ds; + int error; + char *name; + + /* alloc a buffer to hold dsname@snapname plus terminating NULL */ + name = kmem_asprintf("%s@%s", dsname, ha->snapname); + error = dsl_dataset_hold(name, ha->dstg, &ds); + strfree(name); + if (error == 0) { + ha->gotone = B_TRUE; + dsl_sync_task_create(ha->dstg, dsl_dataset_user_hold_check, + dsl_dataset_user_hold_sync, ds, ha, 0); + } else if (error == ENOENT && ha->recursive) { + error = 0; + } else { + (void) strlcpy(ha->failed, dsname, sizeof (ha->failed)); + } + return (error); +} + +int +dsl_dataset_user_hold_for_send(dsl_dataset_t *ds, char *htag, + boolean_t temphold) +{ + struct dsl_ds_holdarg *ha; + int error; + + ha = kmem_zalloc(sizeof (struct dsl_ds_holdarg), KM_SLEEP); + ha->htag = htag; + ha->temphold = temphold; + error = dsl_sync_task_do(ds->ds_dir->dd_pool, + dsl_dataset_user_hold_check, dsl_dataset_user_hold_sync, + ds, ha, 0); + kmem_free(ha, sizeof (struct dsl_ds_holdarg)); + + return (error); +} + +int +dsl_dataset_user_hold(char *dsname, char *snapname, char *htag, + boolean_t recursive, boolean_t temphold, int cleanup_fd) +{ + struct dsl_ds_holdarg *ha; + dsl_sync_task_t *dst; + spa_t *spa; + int error; + minor_t minor = 0; + + if (cleanup_fd != -1) { + /* Currently we only support cleanup-on-exit of tempholds. */ + if (!temphold) + return (EINVAL); + error = zfs_onexit_fd_hold(cleanup_fd, &minor); + if (error) + return (error); + } + + ha = kmem_zalloc(sizeof (struct dsl_ds_holdarg), KM_SLEEP); + + (void) strlcpy(ha->failed, dsname, sizeof (ha->failed)); + + error = spa_open(dsname, &spa, FTAG); + if (error) { + kmem_free(ha, sizeof (struct dsl_ds_holdarg)); + if (cleanup_fd != -1) + zfs_onexit_fd_rele(cleanup_fd); + return (error); + } + + ha->dstg = dsl_sync_task_group_create(spa_get_dsl(spa)); + ha->htag = htag; + ha->snapname = snapname; + ha->recursive = recursive; + ha->temphold = temphold; + + if (recursive) { + error = dmu_objset_find(dsname, dsl_dataset_user_hold_one, + ha, DS_FIND_CHILDREN); + } else { + error = dsl_dataset_user_hold_one(dsname, ha); + } + if (error == 0) + error = dsl_sync_task_group_wait(ha->dstg); + + for (dst = list_head(&ha->dstg->dstg_tasks); dst; + dst = list_next(&ha->dstg->dstg_tasks, dst)) { + dsl_dataset_t *ds = dst->dst_arg1; + + if (dst->dst_err) { + dsl_dataset_name(ds, ha->failed); + *strchr(ha->failed, '@') = '\0'; + } else if (error == 0 && minor != 0 && temphold) { + /* + * If this hold is to be released upon process exit, + * register that action now. + */ + dsl_register_onexit_hold_cleanup(ds, htag, minor); + } + dsl_dataset_rele(ds, ha->dstg); + } + + if (error == 0 && recursive && !ha->gotone) + error = ENOENT; + + if (error) + (void) strlcpy(dsname, ha->failed, sizeof (ha->failed)); + + dsl_sync_task_group_destroy(ha->dstg); + + kmem_free(ha, sizeof (struct dsl_ds_holdarg)); + spa_close(spa, FTAG); + if (cleanup_fd != -1) + zfs_onexit_fd_rele(cleanup_fd); + return (error); +} + +struct dsl_ds_releasearg { + dsl_dataset_t *ds; + const char *htag; + boolean_t own; /* do we own or just hold ds? */ +}; + +static int +dsl_dataset_release_might_destroy(dsl_dataset_t *ds, const char *htag, + boolean_t *might_destroy) +{ + objset_t *mos = ds->ds_dir->dd_pool->dp_meta_objset; + uint64_t zapobj; + uint64_t tmp; + int error; + + *might_destroy = B_FALSE; + + mutex_enter(&ds->ds_lock); + zapobj = ds->ds_phys->ds_userrefs_obj; + if (zapobj == 0) { + /* The tag can't possibly exist */ + mutex_exit(&ds->ds_lock); + return (ESRCH); + } + + /* Make sure the tag exists */ + error = zap_lookup(mos, zapobj, htag, 8, 1, &tmp); + if (error) { + mutex_exit(&ds->ds_lock); + if (error == ENOENT) + error = ESRCH; + return (error); + } + + if (ds->ds_userrefs == 1 && ds->ds_phys->ds_num_children == 1 && + DS_IS_DEFER_DESTROY(ds)) + *might_destroy = B_TRUE; + + mutex_exit(&ds->ds_lock); + return (0); +} + +static int +dsl_dataset_user_release_check(void *arg1, void *tag, dmu_tx_t *tx) +{ + struct dsl_ds_releasearg *ra = arg1; + dsl_dataset_t *ds = ra->ds; + boolean_t might_destroy; + int error; + + if (spa_version(ds->ds_dir->dd_pool->dp_spa) < SPA_VERSION_USERREFS) + return (ENOTSUP); + + error = dsl_dataset_release_might_destroy(ds, ra->htag, &might_destroy); + if (error) + return (error); + + if (might_destroy) { + struct dsl_ds_destroyarg dsda = {0}; + + if (dmu_tx_is_syncing(tx)) { + /* + * If we're not prepared to remove the snapshot, + * we can't allow the release to happen right now. + */ + if (!ra->own) + return (EBUSY); + } + dsda.ds = ds; + dsda.releasing = B_TRUE; + return (dsl_dataset_destroy_check(&dsda, tag, tx)); + } + + return (0); +} + +static void +dsl_dataset_user_release_sync(void *arg1, void *tag, dmu_tx_t *tx) +{ + struct dsl_ds_releasearg *ra = arg1; + dsl_dataset_t *ds = ra->ds; + dsl_pool_t *dp = ds->ds_dir->dd_pool; + objset_t *mos = dp->dp_meta_objset; + uint64_t zapobj; + uint64_t dsobj = ds->ds_object; + uint64_t refs; + int error; + + mutex_enter(&ds->ds_lock); + ds->ds_userrefs--; + refs = ds->ds_userrefs; + mutex_exit(&ds->ds_lock); + error = dsl_pool_user_release(dp, ds->ds_object, ra->htag, tx); + VERIFY(error == 0 || error == ENOENT); + zapobj = ds->ds_phys->ds_userrefs_obj; + VERIFY(0 == zap_remove(mos, zapobj, ra->htag, tx)); + if (ds->ds_userrefs == 0 && ds->ds_phys->ds_num_children == 1 && + DS_IS_DEFER_DESTROY(ds)) { + struct dsl_ds_destroyarg dsda = {0}; + + ASSERT(ra->own); + dsda.ds = ds; + dsda.releasing = B_TRUE; + /* We already did the destroy_check */ + dsl_dataset_destroy_sync(&dsda, tag, tx); + } + + spa_history_log_internal(LOG_DS_USER_RELEASE, + dp->dp_spa, tx, "<%s> %lld dataset = %llu", + ra->htag, (longlong_t)refs, dsobj); +} + +static int +dsl_dataset_user_release_one(const char *dsname, void *arg) +{ + struct dsl_ds_holdarg *ha = arg; + struct dsl_ds_releasearg *ra; + dsl_dataset_t *ds; + int error; + void *dtag = ha->dstg; + char *name; + boolean_t own = B_FALSE; + boolean_t might_destroy; + + /* alloc a buffer to hold dsname@snapname, plus the terminating NULL */ + name = kmem_asprintf("%s@%s", dsname, ha->snapname); + error = dsl_dataset_hold(name, dtag, &ds); + strfree(name); + if (error == ENOENT && ha->recursive) + return (0); + (void) strlcpy(ha->failed, dsname, sizeof (ha->failed)); + if (error) + return (error); + + ha->gotone = B_TRUE; + + ASSERT(dsl_dataset_is_snapshot(ds)); + + error = dsl_dataset_release_might_destroy(ds, ha->htag, &might_destroy); + if (error) { + dsl_dataset_rele(ds, dtag); + return (error); + } + + if (might_destroy) { +#ifdef _KERNEL + name = kmem_asprintf("%s@%s", dsname, ha->snapname); + error = zfs_unmount_snap(name, NULL); + strfree(name); + if (error) { + dsl_dataset_rele(ds, dtag); + return (error); + } +#endif + if (!dsl_dataset_tryown(ds, B_TRUE, dtag)) { + dsl_dataset_rele(ds, dtag); + return (EBUSY); + } else { + own = B_TRUE; + dsl_dataset_make_exclusive(ds, dtag); + } + } + + ra = kmem_alloc(sizeof (struct dsl_ds_releasearg), KM_SLEEP); + ra->ds = ds; + ra->htag = ha->htag; + ra->own = own; + dsl_sync_task_create(ha->dstg, dsl_dataset_user_release_check, + dsl_dataset_user_release_sync, ra, dtag, 0); + + return (0); +} + +int +dsl_dataset_user_release(char *dsname, char *snapname, char *htag, + boolean_t recursive) +{ + struct dsl_ds_holdarg *ha; + dsl_sync_task_t *dst; + spa_t *spa; + int error; + +top: + ha = kmem_zalloc(sizeof (struct dsl_ds_holdarg), KM_SLEEP); + + (void) strlcpy(ha->failed, dsname, sizeof (ha->failed)); + + error = spa_open(dsname, &spa, FTAG); + if (error) { + kmem_free(ha, sizeof (struct dsl_ds_holdarg)); + return (error); + } + + ha->dstg = dsl_sync_task_group_create(spa_get_dsl(spa)); + ha->htag = htag; + ha->snapname = snapname; + ha->recursive = recursive; + if (recursive) { + error = dmu_objset_find(dsname, dsl_dataset_user_release_one, + ha, DS_FIND_CHILDREN); + } else { + error = dsl_dataset_user_release_one(dsname, ha); + } + if (error == 0) + error = dsl_sync_task_group_wait(ha->dstg); + + for (dst = list_head(&ha->dstg->dstg_tasks); dst; + dst = list_next(&ha->dstg->dstg_tasks, dst)) { + struct dsl_ds_releasearg *ra = dst->dst_arg1; + dsl_dataset_t *ds = ra->ds; + + if (dst->dst_err) + dsl_dataset_name(ds, ha->failed); + + if (ra->own) + dsl_dataset_disown(ds, ha->dstg); + else + dsl_dataset_rele(ds, ha->dstg); + + kmem_free(ra, sizeof (struct dsl_ds_releasearg)); + } + + if (error == 0 && recursive && !ha->gotone) + error = ENOENT; + + if (error && error != EBUSY) + (void) strlcpy(dsname, ha->failed, sizeof (ha->failed)); + + dsl_sync_task_group_destroy(ha->dstg); + kmem_free(ha, sizeof (struct dsl_ds_holdarg)); + spa_close(spa, FTAG); + + /* + * We can get EBUSY if we were racing with deferred destroy and + * dsl_dataset_user_release_check() hadn't done the necessary + * open context setup. We can also get EBUSY if we're racing + * with destroy and that thread is the ds_owner. Either way + * the busy condition should be transient, and we should retry + * the release operation. + */ + if (error == EBUSY) + goto top; + + return (error); +} + +/* + * Called at spa_load time (with retry == B_FALSE) to release a stale + * temporary user hold. Also called by the onexit code (with retry == B_TRUE). + */ +int +dsl_dataset_user_release_tmp(dsl_pool_t *dp, uint64_t dsobj, char *htag, + boolean_t retry) +{ + dsl_dataset_t *ds; + char *snap; + char *name; + int namelen; + int error; + + do { + rw_enter(&dp->dp_config_rwlock, RW_READER); + error = dsl_dataset_hold_obj(dp, dsobj, FTAG, &ds); + rw_exit(&dp->dp_config_rwlock); + if (error) + return (error); + namelen = dsl_dataset_namelen(ds)+1; + name = kmem_alloc(namelen, KM_SLEEP); + dsl_dataset_name(ds, name); + dsl_dataset_rele(ds, FTAG); + + snap = strchr(name, '@'); + *snap = '\0'; + ++snap; + error = dsl_dataset_user_release(name, snap, htag, B_FALSE); + kmem_free(name, namelen); + + /* + * The object can't have been destroyed because we have a hold, + * but it might have been renamed, resulting in ENOENT. Retry + * if we've been requested to do so. + * + * It would be nice if we could use the dsobj all the way + * through and avoid ENOENT entirely. But we might need to + * unmount the snapshot, and there's currently no way to lookup + * a vfsp using a ZFS object id. + */ + } while ((error == ENOENT) && retry); + + return (error); +} + +int +dsl_dataset_get_holds(const char *dsname, nvlist_t **nvp) +{ + dsl_dataset_t *ds; + int err; + + err = dsl_dataset_hold(dsname, FTAG, &ds); + if (err) + return (err); + + VERIFY(0 == nvlist_alloc(nvp, NV_UNIQUE_NAME, KM_SLEEP)); + if (ds->ds_phys->ds_userrefs_obj != 0) { + zap_attribute_t *za; + zap_cursor_t zc; + + za = kmem_alloc(sizeof (zap_attribute_t), KM_SLEEP); + for (zap_cursor_init(&zc, ds->ds_dir->dd_pool->dp_meta_objset, + ds->ds_phys->ds_userrefs_obj); + zap_cursor_retrieve(&zc, za) == 0; + zap_cursor_advance(&zc)) { + VERIFY(0 == nvlist_add_uint64(*nvp, za->za_name, + za->za_first_integer)); + } + zap_cursor_fini(&zc); + kmem_free(za, sizeof (zap_attribute_t)); + } + dsl_dataset_rele(ds, FTAG); + return (0); +} + +/* + * Note, this fuction is used as the callback for dmu_objset_find(). We + * always return 0 so that we will continue to find and process + * inconsistent datasets, even if we encounter an error trying to + * process one of them. + */ +/* ARGSUSED */ +int +dsl_destroy_inconsistent(const char *dsname, void *arg) +{ + dsl_dataset_t *ds; + + if (dsl_dataset_own(dsname, B_TRUE, FTAG, &ds) == 0) { + if (DS_IS_INCONSISTENT(ds)) + (void) dsl_dataset_destroy(ds, FTAG, B_FALSE); + else + dsl_dataset_disown(ds, FTAG); + } + return (0); +} |