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Diffstat (limited to 'module/zfs/dmu_redact.c')
| -rw-r--r-- | module/zfs/dmu_redact.c | 1186 |
1 files changed, 1186 insertions, 0 deletions
diff --git a/module/zfs/dmu_redact.c b/module/zfs/dmu_redact.c new file mode 100644 index 000000000000..df10d8d6faae --- /dev/null +++ b/module/zfs/dmu_redact.c @@ -0,0 +1,1186 @@ +/* + * 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) 2017, 2018 by Delphix. All rights reserved. + */ + +#include <sys/zfs_context.h> +#include <sys/txg.h> +#include <sys/dmu_objset.h> +#include <sys/dmu_traverse.h> +#include <sys/dmu_redact.h> +#include <sys/bqueue.h> +#include <sys/objlist.h> +#include <sys/dmu_tx.h> +#ifdef _KERNEL +#include <sys/zfs_vfsops.h> +#include <sys/zap.h> +#include <sys/zfs_znode.h> +#endif + +/* + * This controls the number of entries in the buffer the redaction_list_update + * synctask uses to buffer writes to the redaction list. + */ +int redact_sync_bufsize = 1024; + +/* + * Controls how often to update the redaction list when creating a redaction + * list. + */ +uint64_t redaction_list_update_interval_ns = 1000 * 1000 * 1000ULL; /* NS */ + +/* + * This tunable controls the length of the queues that zfs redact worker threads + * use to communicate. If the dmu_redact_snap thread is blocking on these + * queues, this variable may need to be increased. If there is a significant + * slowdown at the start of a redact operation as these threads consume all the + * available IO resources, or the queues are consuming too much memory, this + * variable may need to be decreased. + */ +int zfs_redact_queue_length = 1024 * 1024; + +/* + * These tunables control the fill fraction of the queues by zfs redact. The + * fill fraction controls the frequency with which threads have to be + * cv_signaled. If a lot of cpu time is being spent on cv_signal, then these + * should be tuned down. If the queues empty before the signalled thread can + * catch up, then these should be tuned up. + */ +uint64_t zfs_redact_queue_ff = 20; + +struct redact_record { + bqueue_node_t ln; + boolean_t eos_marker; /* Marks the end of the stream */ + uint64_t start_object; + uint64_t start_blkid; + uint64_t end_object; + uint64_t end_blkid; + uint8_t indblkshift; + uint32_t datablksz; +}; + +struct redact_thread_arg { + bqueue_t q; + objset_t *os; /* Objset to traverse */ + dsl_dataset_t *ds; /* Dataset to traverse */ + struct redact_record *current_record; + int error_code; + boolean_t cancel; + zbookmark_phys_t resume; + objlist_t *deleted_objs; + uint64_t *num_blocks_visited; + uint64_t ignore_object; /* ignore further callbacks on this */ + uint64_t txg; /* txg to traverse since */ +}; + +/* + * The redaction node is a wrapper around the redaction record that is used + * by the redaction merging thread to sort the records and determine overlaps. + * + * It contains two nodes; one sorts the records by their start_zb, and the other + * sorts the records by their end_zb. + */ +struct redact_node { + avl_node_t avl_node_start; + avl_node_t avl_node_end; + struct redact_record *record; + struct redact_thread_arg *rt_arg; + uint32_t thread_num; +}; + +struct merge_data { + list_t md_redact_block_pending; + redact_block_phys_t md_coalesce_block; + uint64_t md_last_time; + redact_block_phys_t md_furthest[TXG_SIZE]; + /* Lists of struct redact_block_list_node. */ + list_t md_blocks[TXG_SIZE]; + boolean_t md_synctask_txg[TXG_SIZE]; + uint64_t md_latest_synctask_txg; + redaction_list_t *md_redaction_list; +}; + +/* + * A wrapper around struct redact_block so it can be stored in a list_t. + */ +struct redact_block_list_node { + redact_block_phys_t block; + list_node_t node; +}; + +/* + * We've found a new redaction candidate. In order to improve performance, we + * coalesce these blocks when they're adjacent to each other. This function + * handles that. If the new candidate block range is immediately after the + * range we're building, coalesce it into the range we're building. Otherwise, + * put the record we're building on the queue, and update the build pointer to + * point to the new record. + */ +static void +record_merge_enqueue(bqueue_t *q, struct redact_record **build, + struct redact_record *new) +{ + if (new->eos_marker) { + if (*build != NULL) + bqueue_enqueue(q, *build, sizeof (*build)); + bqueue_enqueue_flush(q, new, sizeof (*new)); + return; + } + if (*build == NULL) { + *build = new; + return; + } + struct redact_record *curbuild = *build; + if ((curbuild->end_object == new->start_object && + curbuild->end_blkid + 1 == new->start_blkid && + curbuild->end_blkid != UINT64_MAX) || + (curbuild->end_object + 1 == new->start_object && + curbuild->end_blkid == UINT64_MAX && new->start_blkid == 0)) { + curbuild->end_object = new->end_object; + curbuild->end_blkid = new->end_blkid; + kmem_free(new, sizeof (*new)); + } else { + bqueue_enqueue(q, curbuild, sizeof (*curbuild)); + *build = new; + } +} +#ifdef _KERNEL +struct objnode { + avl_node_t node; + uint64_t obj; +}; + +static int +objnode_compare(const void *o1, const void *o2) +{ + const struct objnode *obj1 = o1; + const struct objnode *obj2 = o2; + if (obj1->obj < obj2->obj) + return (-1); + if (obj1->obj > obj2->obj) + return (1); + return (0); +} + + +static objlist_t * +zfs_get_deleteq(objset_t *os) +{ + objlist_t *deleteq_objlist = objlist_create(); + uint64_t deleteq_obj; + zap_cursor_t zc; + zap_attribute_t za; + dmu_object_info_t doi; + + ASSERT3U(os->os_phys->os_type, ==, DMU_OST_ZFS); + VERIFY0(dmu_object_info(os, MASTER_NODE_OBJ, &doi)); + ASSERT3U(doi.doi_type, ==, DMU_OT_MASTER_NODE); + + VERIFY0(zap_lookup(os, MASTER_NODE_OBJ, + ZFS_UNLINKED_SET, sizeof (uint64_t), 1, &deleteq_obj)); + + /* + * In order to insert objects into the objlist, they must be in sorted + * order. We don't know what order we'll get them out of the ZAP in, so + * we insert them into and remove them from an avl_tree_t to sort them. + */ + avl_tree_t at; + avl_create(&at, objnode_compare, sizeof (struct objnode), + offsetof(struct objnode, node)); + + for (zap_cursor_init(&zc, os, deleteq_obj); + zap_cursor_retrieve(&zc, &za) == 0; zap_cursor_advance(&zc)) { + struct objnode *obj = kmem_zalloc(sizeof (*obj), KM_SLEEP); + obj->obj = za.za_first_integer; + avl_add(&at, obj); + } + zap_cursor_fini(&zc); + + struct objnode *next, *found = avl_first(&at); + while (found != NULL) { + next = AVL_NEXT(&at, found); + objlist_insert(deleteq_objlist, found->obj); + found = next; + } + + void *cookie = NULL; + while ((found = avl_destroy_nodes(&at, &cookie)) != NULL) + kmem_free(found, sizeof (*found)); + avl_destroy(&at); + return (deleteq_objlist); +} +#endif + +/* + * This is the callback function to traverse_dataset for the redaction threads + * for dmu_redact_snap. This thread is responsible for creating redaction + * records for all the data that is modified by the snapshots we're redacting + * with respect to. Redaction records represent ranges of data that have been + * modified by one of the redaction snapshots, and are stored in the + * redact_record struct. We need to create redaction records for three + * cases: + * + * First, if there's a normal write, we need to create a redaction record for + * that block. + * + * Second, if there's a hole, we need to create a redaction record that covers + * the whole range of the hole. If the hole is in the meta-dnode, it must cover + * every block in all of the objects in the hole. + * + * Third, if there is a deleted object, we need to create a redaction record for + * all of the blocks in that object. + */ +/*ARGSUSED*/ +static int +redact_cb(spa_t *spa, zilog_t *zilog, const blkptr_t *bp, + const zbookmark_phys_t *zb, const struct dnode_phys *dnp, void *arg) +{ + struct redact_thread_arg *rta = arg; + struct redact_record *record; + + ASSERT(zb->zb_object == DMU_META_DNODE_OBJECT || + zb->zb_object >= rta->resume.zb_object); + + if (rta->cancel) + return (SET_ERROR(EINTR)); + + if (rta->ignore_object == zb->zb_object) + return (0); + + /* + * If we're visiting a dnode, we need to handle the case where the + * object has been deleted. + */ + if (zb->zb_level == ZB_DNODE_LEVEL) { + ASSERT3U(zb->zb_level, ==, ZB_DNODE_LEVEL); + + if (zb->zb_object == 0) + return (0); + + /* + * If the object has been deleted, redact all of the blocks in + * it. + */ + if (dnp->dn_type == DMU_OT_NONE || + objlist_exists(rta->deleted_objs, zb->zb_object)) { + rta->ignore_object = zb->zb_object; + record = kmem_zalloc(sizeof (struct redact_record), + KM_SLEEP); + + record->eos_marker = B_FALSE; + record->start_object = record->end_object = + zb->zb_object; + record->start_blkid = 0; + record->end_blkid = UINT64_MAX; + record_merge_enqueue(&rta->q, + &rta->current_record, record); + } + return (0); + } else if (zb->zb_level < 0) { + return (0); + } else if (zb->zb_level > 0 && !BP_IS_HOLE(bp)) { + /* + * If this is an indirect block, but not a hole, it doesn't + * provide any useful information for redaction, so ignore it. + */ + return (0); + } + + /* + * At this point, there are two options left for the type of block we're + * looking at. Either this is a hole (which could be in the dnode or + * the meta-dnode), or it's a level 0 block of some sort. If it's a + * hole, we create a redaction record that covers the whole range. If + * the hole is in a dnode, we need to redact all the blocks in that + * hole. If the hole is in the meta-dnode, we instead need to redact + * all blocks in every object covered by that hole. If it's a level 0 + * block, we only need to redact that single block. + */ + record = kmem_zalloc(sizeof (struct redact_record), KM_SLEEP); + record->eos_marker = B_FALSE; + + record->start_object = record->end_object = zb->zb_object; + if (BP_IS_HOLE(bp)) { + record->start_blkid = zb->zb_blkid * + bp_span_in_blocks(dnp->dn_indblkshift, zb->zb_level); + + record->end_blkid = ((zb->zb_blkid + 1) * + bp_span_in_blocks(dnp->dn_indblkshift, zb->zb_level)) - 1; + + if (zb->zb_object == DMU_META_DNODE_OBJECT) { + record->start_object = record->start_blkid * + ((SPA_MINBLOCKSIZE * dnp->dn_datablkszsec) / + sizeof (dnode_phys_t)); + record->start_blkid = 0; + record->end_object = ((record->end_blkid + + 1) * ((SPA_MINBLOCKSIZE * dnp->dn_datablkszsec) / + sizeof (dnode_phys_t))) - 1; + record->end_blkid = UINT64_MAX; + } + } else if (zb->zb_level != 0 || + zb->zb_object == DMU_META_DNODE_OBJECT) { + kmem_free(record, sizeof (*record)); + return (0); + } else { + record->start_blkid = record->end_blkid = zb->zb_blkid; + } + record->indblkshift = dnp->dn_indblkshift; + record->datablksz = dnp->dn_datablkszsec << SPA_MINBLOCKSHIFT; + record_merge_enqueue(&rta->q, &rta->current_record, record); + + return (0); +} + +static void +redact_traverse_thread(void *arg) +{ + struct redact_thread_arg *rt_arg = arg; + int err; + struct redact_record *data; +#ifdef _KERNEL + if (rt_arg->os->os_phys->os_type == DMU_OST_ZFS) + rt_arg->deleted_objs = zfs_get_deleteq(rt_arg->os); + else + rt_arg->deleted_objs = objlist_create(); +#else + rt_arg->deleted_objs = objlist_create(); +#endif + + err = traverse_dataset_resume(rt_arg->ds, rt_arg->txg, + &rt_arg->resume, TRAVERSE_PRE | TRAVERSE_PREFETCH_METADATA, + redact_cb, rt_arg); + + if (err != EINTR) + rt_arg->error_code = err; + objlist_destroy(rt_arg->deleted_objs); + data = kmem_zalloc(sizeof (*data), KM_SLEEP); + data->eos_marker = B_TRUE; + record_merge_enqueue(&rt_arg->q, &rt_arg->current_record, data); + thread_exit(); +} + +static inline void +create_zbookmark_from_obj_off(zbookmark_phys_t *zb, uint64_t object, + uint64_t blkid) +{ + zb->zb_object = object; + zb->zb_level = 0; + zb->zb_blkid = blkid; +} + +/* + * This is a utility function that can do the comparison for the start or ends + * of the ranges in a redact_record. + */ +static int +redact_range_compare(uint64_t obj1, uint64_t off1, uint32_t dbss1, + uint64_t obj2, uint64_t off2, uint32_t dbss2) +{ + zbookmark_phys_t z1, z2; + create_zbookmark_from_obj_off(&z1, obj1, off1); + create_zbookmark_from_obj_off(&z2, obj2, off2); + + return (zbookmark_compare(dbss1 >> SPA_MINBLOCKSHIFT, 0, + dbss2 >> SPA_MINBLOCKSHIFT, 0, &z1, &z2)); +} + +/* + * Compare two redaction records by their range's start location. Also makes + * eos records always compare last. We use the thread number in the redact_node + * to ensure that records do not compare equal (which is not allowed in our avl + * trees). + */ +static int +redact_node_compare_start(const void *arg1, const void *arg2) +{ + const struct redact_node *rn1 = arg1; + const struct redact_node *rn2 = arg2; + const struct redact_record *rr1 = rn1->record; + const struct redact_record *rr2 = rn2->record; + if (rr1->eos_marker) + return (1); + if (rr2->eos_marker) + return (-1); + + int cmp = redact_range_compare(rr1->start_object, rr1->start_blkid, + rr1->datablksz, rr2->start_object, rr2->start_blkid, + rr2->datablksz); + if (cmp == 0) + cmp = (rn1->thread_num < rn2->thread_num ? -1 : 1); + return (cmp); +} + +/* + * Compare two redaction records by their range's end location. Also makes + * eos records always compare last. We use the thread number in the redact_node + * to ensure that records do not compare equal (which is not allowed in our avl + * trees). + */ +static int +redact_node_compare_end(const void *arg1, const void *arg2) +{ + const struct redact_node *rn1 = arg1; + const struct redact_node *rn2 = arg2; + const struct redact_record *srr1 = rn1->record; + const struct redact_record *srr2 = rn2->record; + if (srr1->eos_marker) + return (1); + if (srr2->eos_marker) + return (-1); + + int cmp = redact_range_compare(srr1->end_object, srr1->end_blkid, + srr1->datablksz, srr2->end_object, srr2->end_blkid, + srr2->datablksz); + if (cmp == 0) + cmp = (rn1->thread_num < rn2->thread_num ? -1 : 1); + return (cmp); +} + +/* + * Utility function that compares two redaction records to determine if any part + * of the "from" record is before any part of the "to" record. Also causes End + * of Stream redaction records to compare after all others, so that the + * redaction merging logic can stay simple. + */ +static boolean_t +redact_record_before(const struct redact_record *from, + const struct redact_record *to) +{ + if (from->eos_marker == B_TRUE) + return (B_FALSE); + else if (to->eos_marker == B_TRUE) + return (B_TRUE); + return (redact_range_compare(from->start_object, from->start_blkid, + from->datablksz, to->end_object, to->end_blkid, + to->datablksz) <= 0); +} + +/* + * Pop a new redaction record off the queue, check that the records are in the + * right order, and free the old data. + */ +static struct redact_record * +get_next_redact_record(bqueue_t *bq, struct redact_record *prev) +{ + struct redact_record *next = bqueue_dequeue(bq); + ASSERT(redact_record_before(prev, next)); + kmem_free(prev, sizeof (*prev)); + return (next); +} + +/* + * Remove the given redaction node from both trees, pull a new redaction record + * off the queue, free the old redaction record, update the redaction node, and + * reinsert the node into the trees. + */ +static int +update_avl_trees(avl_tree_t *start_tree, avl_tree_t *end_tree, + struct redact_node *redact_node) +{ + avl_remove(start_tree, redact_node); + avl_remove(end_tree, redact_node); + redact_node->record = get_next_redact_record(&redact_node->rt_arg->q, + redact_node->record); + avl_add(end_tree, redact_node); + avl_add(start_tree, redact_node); + return (redact_node->rt_arg->error_code); +} + +/* + * Synctask for updating redaction lists. We first take this txg's list of + * redacted blocks and append those to the redaction list. We then update the + * redaction list's bonus buffer. We store the furthest blocks we visited and + * the list of snapshots that we're redacting with respect to. We need these so + * that redacted sends and receives can be correctly resumed. + */ +static void +redaction_list_update_sync(void *arg, dmu_tx_t *tx) +{ + struct merge_data *md = arg; + uint64_t txg = dmu_tx_get_txg(tx); + list_t *list = &md->md_blocks[txg & TXG_MASK]; + redact_block_phys_t *furthest_visited = + &md->md_furthest[txg & TXG_MASK]; + objset_t *mos = tx->tx_pool->dp_meta_objset; + redaction_list_t *rl = md->md_redaction_list; + int bufsize = redact_sync_bufsize; + redact_block_phys_t *buf = kmem_alloc(bufsize * sizeof (*buf), + KM_SLEEP); + int index = 0; + + dmu_buf_will_dirty(rl->rl_dbuf, tx); + + for (struct redact_block_list_node *rbln = list_remove_head(list); + rbln != NULL; rbln = list_remove_head(list)) { + ASSERT3U(rbln->block.rbp_object, <=, + furthest_visited->rbp_object); + ASSERT(rbln->block.rbp_object < furthest_visited->rbp_object || + rbln->block.rbp_blkid <= furthest_visited->rbp_blkid); + buf[index] = rbln->block; + index++; + if (index == bufsize) { + dmu_write(mos, rl->rl_object, + rl->rl_phys->rlp_num_entries * sizeof (*buf), + bufsize * sizeof (*buf), buf, tx); + rl->rl_phys->rlp_num_entries += bufsize; + index = 0; + } + kmem_free(rbln, sizeof (*rbln)); + } + if (index > 0) { + dmu_write(mos, rl->rl_object, rl->rl_phys->rlp_num_entries * + sizeof (*buf), index * sizeof (*buf), buf, tx); + rl->rl_phys->rlp_num_entries += index; + } + kmem_free(buf, bufsize * sizeof (*buf)); + + md->md_synctask_txg[txg & TXG_MASK] = B_FALSE; + rl->rl_phys->rlp_last_object = furthest_visited->rbp_object; + rl->rl_phys->rlp_last_blkid = furthest_visited->rbp_blkid; +} + +static void +commit_rl_updates(objset_t *os, struct merge_data *md, uint64_t object, + uint64_t blkid) +{ + dmu_tx_t *tx = dmu_tx_create_dd(spa_get_dsl(os->os_spa)->dp_mos_dir); + dmu_tx_hold_space(tx, sizeof (struct redact_block_list_node)); + VERIFY0(dmu_tx_assign(tx, TXG_WAIT)); + uint64_t txg = dmu_tx_get_txg(tx); + if (!md->md_synctask_txg[txg & TXG_MASK]) { + dsl_sync_task_nowait(dmu_tx_pool(tx), + redaction_list_update_sync, md, 5, ZFS_SPACE_CHECK_NONE, + tx); + md->md_synctask_txg[txg & TXG_MASK] = B_TRUE; + md->md_latest_synctask_txg = txg; + } + md->md_furthest[txg & TXG_MASK].rbp_object = object; + md->md_furthest[txg & TXG_MASK].rbp_blkid = blkid; + list_move_tail(&md->md_blocks[txg & TXG_MASK], + &md->md_redact_block_pending); + dmu_tx_commit(tx); + md->md_last_time = gethrtime(); +} + +/* + * We want to store the list of blocks that we're redacting in the bookmark's + * redaction list. However, this list is stored in the MOS, which means it can + * only be written to in syncing context. To get around this, we create a + * synctask that will write to the mos for us. We tell it what to write by + * a linked list for each current transaction group; every time we decide to + * redact a block, we append it to the transaction group that is currently in + * open context. We also update some progress information that the synctask + * will store to enable resumable redacted sends. + */ +static void +update_redaction_list(struct merge_data *md, objset_t *os, + uint64_t object, uint64_t blkid, uint64_t endblkid, uint32_t blksz) +{ + boolean_t enqueue = B_FALSE; + redact_block_phys_t cur = {0}; + uint64_t count = endblkid - blkid + 1; + while (count > REDACT_BLOCK_MAX_COUNT) { + update_redaction_list(md, os, object, blkid, + blkid + REDACT_BLOCK_MAX_COUNT - 1, blksz); + blkid += REDACT_BLOCK_MAX_COUNT; + count -= REDACT_BLOCK_MAX_COUNT; + } + redact_block_phys_t *coalesce = &md->md_coalesce_block; + boolean_t new; + if (coalesce->rbp_size_count == 0) { + new = B_TRUE; + enqueue = B_FALSE; + } else { + uint64_t old_count = redact_block_get_count(coalesce); + if (coalesce->rbp_object == object && + coalesce->rbp_blkid + old_count == blkid && + old_count + count <= REDACT_BLOCK_MAX_COUNT) { + ASSERT3U(redact_block_get_size(coalesce), ==, blksz); + redact_block_set_count(coalesce, old_count + count); + new = B_FALSE; + enqueue = B_FALSE; + } else { + new = B_TRUE; + enqueue = B_TRUE; + } + } + + if (new) { + cur = *coalesce; + coalesce->rbp_blkid = blkid; + coalesce->rbp_object = object; + + redact_block_set_count(coalesce, count); + redact_block_set_size(coalesce, blksz); + } + + if (enqueue && redact_block_get_size(&cur) != 0) { + struct redact_block_list_node *rbln = + kmem_alloc(sizeof (struct redact_block_list_node), + KM_SLEEP); + rbln->block = cur; + list_insert_tail(&md->md_redact_block_pending, rbln); + } + + if (gethrtime() > md->md_last_time + + redaction_list_update_interval_ns) { + commit_rl_updates(os, md, object, blkid); + } +} + +/* + * This thread merges all the redaction records provided by the worker threads, + * and determines which blocks are redacted by all the snapshots. The algorithm + * for doing so is similar to performing a merge in mergesort with n sub-lists + * instead of 2, with some added complexity due to the fact that the entries are + * ranges, not just single blocks. This algorithm relies on the fact that the + * queues are sorted, which is ensured by the fact that traverse_dataset + * traverses the dataset in a consistent order. We pull one entry off the front + * of the queues of each secure dataset traversal thread. Then we repeat the + * following: each record represents a range of blocks modified by one of the + * redaction snapshots, and each block in that range may need to be redacted in + * the send stream. Find the record with the latest start of its range, and the + * record with the earliest end of its range. If the last start is before the + * first end, then we know that the blocks in the range [last_start, first_end] + * are covered by all of the ranges at the front of the queues, which means + * every thread redacts that whole range. For example, let's say the ranges on + * each queue look like this: + * + * Block Id 1 2 3 4 5 6 7 8 9 10 11 + * Thread 1 | [====================] + * Thread 2 | [========] + * Thread 3 | [=================] + * + * Thread 3 has the last start (5), and the thread 2 has the last end (6). All + * three threads modified the range [5,6], so that data should not be sent over + * the wire. After we've determined whether or not to redact anything, we take + * the record with the first end. We discard that record, and pull a new one + * off the front of the queue it came from. In the above example, we would + * discard Thread 2's record, and pull a new one. Let's say the next record we + * pulled from Thread 2 covered range [10,11]. The new layout would look like + * this: + * + * Block Id 1 2 3 4 5 6 7 8 9 10 11 + * Thread 1 | [====================] + * Thread 2 | [==] + * Thread 3 | [=================] + * + * When we compare the last start (10, from Thread 2) and the first end (9, from + * Thread 1), we see that the last start is greater than the first end. + * Therefore, we do not redact anything from these records. We'll iterate by + * replacing the record from Thread 1. + * + * We iterate by replacing the record with the lowest end because we know + * that the record with the lowest end has helped us as much as it can. All the + * ranges before it that we will ever redact have been redacted. In addition, + * by replacing the one with the lowest end, we guarantee we catch all ranges + * that need to be redacted. For example, if in the case above we had replaced + * the record from Thread 1 instead, we might have ended up with the following: + * + * Block Id 1 2 3 4 5 6 7 8 9 10 11 12 + * Thread 1 | [==] + * Thread 2 | [========] + * Thread 3 | [=================] + * + * If the next record from Thread 2 had been [8,10], for example, we should have + * redacted part of that range, but because we updated Thread 1's record, we + * missed it. + * + * We implement this algorithm by using two trees. The first sorts the + * redaction records by their start_zb, and the second sorts them by their + * end_zb. We use these to find the record with the last start and the record + * with the first end. We create a record with that start and end, and send it + * on. The overall runtime of this implementation is O(n log m), where n is the + * total number of redaction records from all the different redaction snapshots, + * and m is the number of redaction snapshots. + * + * If we redact with respect to zero snapshots, we create a redaction + * record with the start object and blkid to 0, and the end object and blkid to + * UINT64_MAX. This will result in us redacting every block. + */ +static int +perform_thread_merge(bqueue_t *q, uint32_t num_threads, + struct redact_thread_arg *thread_args, boolean_t *cancel) +{ + struct redact_node *redact_nodes = NULL; + avl_tree_t start_tree, end_tree; + struct redact_record *record; + struct redact_record *current_record = NULL; + int err = 0; + struct merge_data md = { {0} }; + list_create(&md.md_redact_block_pending, + sizeof (struct redact_block_list_node), + offsetof(struct redact_block_list_node, node)); + + /* + * If we're redacting with respect to zero snapshots, then no data is + * permitted to be sent. We enqueue a record that redacts all blocks, + * and an eos marker. + */ + if (num_threads == 0) { + record = kmem_zalloc(sizeof (struct redact_record), + KM_SLEEP); + // We can't redact object 0, so don't try. + record->start_object = 1; + record->start_blkid = 0; + record->end_object = record->end_blkid = UINT64_MAX; + bqueue_enqueue(q, record, sizeof (*record)); + return (0); + } + if (num_threads > 0) { + redact_nodes = kmem_zalloc(num_threads * + sizeof (*redact_nodes), KM_SLEEP); + } + + avl_create(&start_tree, redact_node_compare_start, + sizeof (struct redact_node), + offsetof(struct redact_node, avl_node_start)); + avl_create(&end_tree, redact_node_compare_end, + sizeof (struct redact_node), + offsetof(struct redact_node, avl_node_end)); + + for (int i = 0; i < num_threads; i++) { + struct redact_node *node = &redact_nodes[i]; + struct redact_thread_arg *targ = &thread_args[i]; + node->record = bqueue_dequeue(&targ->q); + node->rt_arg = targ; + node->thread_num = i; + avl_add(&start_tree, node); + avl_add(&end_tree, node); + } + + /* + * Once the first record in the end tree has returned EOS, every record + * must be an EOS record, so we should stop. + */ + while (err == 0 && !((struct redact_node *)avl_first(&end_tree))-> + record->eos_marker) { + if (*cancel) { + err = EINTR; + break; + } + struct redact_node *last_start = avl_last(&start_tree); + struct redact_node *first_end = avl_first(&end_tree); + + /* + * If the last start record is before the first end record, + * then we have blocks that are redacted by all threads. + * Therefore, we should redact them. Copy the record, and send + * it to the main thread. + */ + if (redact_record_before(last_start->record, + first_end->record)) { + record = kmem_zalloc(sizeof (struct redact_record), + KM_SLEEP); + *record = *first_end->record; + record->start_object = last_start->record->start_object; + record->start_blkid = last_start->record->start_blkid; + record_merge_enqueue(q, ¤t_record, + record); + } + err = update_avl_trees(&start_tree, &end_tree, first_end); + } + + /* + * We're done; if we were cancelled, we need to cancel our workers and + * clear out their queues. Either way, we need to remove every thread's + * redact_node struct from the avl trees. + */ + for (int i = 0; i < num_threads; i++) { + if (err != 0) { + thread_args[i].cancel = B_TRUE; + while (!redact_nodes[i].record->eos_marker) { + (void) update_avl_trees(&start_tree, &end_tree, + &redact_nodes[i]); + } + } + avl_remove(&start_tree, &redact_nodes[i]); + avl_remove(&end_tree, &redact_nodes[i]); + kmem_free(redact_nodes[i].record, + sizeof (struct redact_record)); + } + + avl_destroy(&start_tree); + avl_destroy(&end_tree); + kmem_free(redact_nodes, num_threads * sizeof (*redact_nodes)); + if (current_record != NULL) + bqueue_enqueue(q, current_record, sizeof (current_record)); + return (err); +} + +struct redact_merge_thread_arg { + bqueue_t q; + spa_t *spa; + int numsnaps; + struct redact_thread_arg *thr_args; + boolean_t cancel; + int error_code; +}; + +static void +redact_merge_thread(void *arg) +{ + struct redact_merge_thread_arg *rmta = arg; + rmta->error_code = perform_thread_merge(&rmta->q, + rmta->numsnaps, rmta->thr_args, &rmta->cancel); + struct redact_record *rec = kmem_zalloc(sizeof (*rec), KM_SLEEP); + rec->eos_marker = B_TRUE; + bqueue_enqueue_flush(&rmta->q, rec, 1); + thread_exit(); +} + +/* + * Find the next object in or after the redaction range passed in, and hold + * its dnode with the provided tag. Also update *object to contain the new + * object number. + */ +static int +hold_next_object(objset_t *os, struct redact_record *rec, void *tag, + uint64_t *object, dnode_t **dn) +{ + int err = 0; + if (*dn != NULL) + dnode_rele(*dn, FTAG); + *dn = NULL; + if (*object < rec->start_object) { + *object = rec->start_object - 1; + } + err = dmu_object_next(os, object, B_FALSE, 0); + if (err != 0) + return (err); + + err = dnode_hold(os, *object, tag, dn); + while (err == 0 && (*object < rec->start_object || + DMU_OT_IS_METADATA((*dn)->dn_type))) { + dnode_rele(*dn, tag); + *dn = NULL; + err = dmu_object_next(os, object, B_FALSE, 0); + if (err != 0) + break; + err = dnode_hold(os, *object, tag, dn); + } + return (err); +} + +static int +perform_redaction(objset_t *os, redaction_list_t *rl, + struct redact_merge_thread_arg *rmta) +{ + int err = 0; + bqueue_t *q = &rmta->q; + struct redact_record *rec = NULL; + struct merge_data md = { {0} }; + + list_create(&md.md_redact_block_pending, + sizeof (struct redact_block_list_node), + offsetof(struct redact_block_list_node, node)); + md.md_redaction_list = rl; + + for (int i = 0; i < TXG_SIZE; i++) { + list_create(&md.md_blocks[i], + sizeof (struct redact_block_list_node), + offsetof(struct redact_block_list_node, node)); + } + dnode_t *dn = NULL; + uint64_t prev_obj = 0; + for (rec = bqueue_dequeue(q); !rec->eos_marker && err == 0; + rec = get_next_redact_record(q, rec)) { + ASSERT3U(rec->start_object, !=, 0); + uint64_t object; + if (prev_obj != rec->start_object) { + object = rec->start_object - 1; + err = hold_next_object(os, rec, FTAG, &object, &dn); + } else { + object = prev_obj; + } + while (err == 0 && object <= rec->end_object) { + if (issig(JUSTLOOKING) && issig(FORREAL)) { + err = EINTR; + break; + } + /* + * Part of the current object is contained somewhere in + * the range covered by rec. + */ + uint64_t startblkid; + uint64_t endblkid; + uint64_t maxblkid = dn->dn_phys->dn_maxblkid; + + if (rec->start_object < object) + startblkid = 0; + else if (rec->start_blkid > maxblkid) + break; + else + startblkid = rec->start_blkid; + + if (rec->end_object > object || rec->end_blkid > + maxblkid) { + endblkid = maxblkid; + } else { + endblkid = rec->end_blkid; + } + update_redaction_list(&md, os, object, startblkid, + endblkid, dn->dn_datablksz); + + if (object == rec->end_object) + break; + err = hold_next_object(os, rec, FTAG, &object, &dn); + } + if (err == ESRCH) + err = 0; + if (dn != NULL) + prev_obj = object; + } + if (err == 0 && dn != NULL) + dnode_rele(dn, FTAG); + + if (err == ESRCH) + err = 0; + rmta->cancel = B_TRUE; + while (!rec->eos_marker) + rec = get_next_redact_record(q, rec); + kmem_free(rec, sizeof (*rec)); + + /* + * There may be a block that's being coalesced, sync that out before we + * return. + */ + if (err == 0 && md.md_coalesce_block.rbp_size_count != 0) { + struct redact_block_list_node *rbln = + kmem_alloc(sizeof (struct redact_block_list_node), + KM_SLEEP); + rbln->block = md.md_coalesce_block; + list_insert_tail(&md.md_redact_block_pending, rbln); + } + commit_rl_updates(os, &md, UINT64_MAX, UINT64_MAX); + + /* + * Wait for all the redaction info to sync out before we return, so that + * anyone who attempts to resume this redaction will have all the data + * they need. + */ + dsl_pool_t *dp = spa_get_dsl(os->os_spa); + if (md.md_latest_synctask_txg != 0) + txg_wait_synced(dp, md.md_latest_synctask_txg); + for (int i = 0; i < TXG_SIZE; i++) + list_destroy(&md.md_blocks[i]); + return (err); +} + +static boolean_t +redact_snaps_contains(uint64_t *snaps, uint64_t num_snaps, uint64_t guid) +{ + for (int i = 0; i < num_snaps; i++) { + if (snaps[i] == guid) + return (B_TRUE); + } + return (B_FALSE); +} + +int +dmu_redact_snap(const char *snapname, nvlist_t *redactnvl, + const char *redactbook) +{ + int err = 0; + dsl_pool_t *dp = NULL; + dsl_dataset_t *ds = NULL; + int numsnaps = 0; + objset_t *os; + struct redact_thread_arg *args = NULL; + redaction_list_t *new_rl = NULL; + + if ((err = dsl_pool_hold(snapname, FTAG, &dp)) != 0) + return (err); + + if ((err = dsl_dataset_hold_flags(dp, snapname, DS_HOLD_FLAG_DECRYPT, + FTAG, &ds)) != 0) { + goto out; + } + dsl_dataset_long_hold(ds, FTAG); + if (!ds->ds_is_snapshot || dmu_objset_from_ds(ds, &os) != 0) { + err = EINVAL; + goto out; + } + if (dsl_dataset_feature_is_active(ds, SPA_FEATURE_REDACTED_DATASETS)) { + err = EALREADY; + goto out; + } + + numsnaps = fnvlist_num_pairs(redactnvl); + if (numsnaps > 0) + args = kmem_zalloc(numsnaps * sizeof (*args), KM_SLEEP); + + nvpair_t *pair = NULL; + for (int i = 0; i < numsnaps; i++) { + pair = nvlist_next_nvpair(redactnvl, pair); + const char *name = nvpair_name(pair); + struct redact_thread_arg *rta = &args[i]; + err = dsl_dataset_hold_flags(dp, name, DS_HOLD_FLAG_DECRYPT, + FTAG, &rta->ds); + if (err != 0) + break; + /* + * We want to do the long hold before we can get any other + * errors, because the cleanup code will release the long + * hold if rta->ds is filled in. + */ + dsl_dataset_long_hold(rta->ds, FTAG); + + err = dmu_objset_from_ds(rta->ds, &rta->os); + if (err != 0) + break; + if (!dsl_dataset_is_before(rta->ds, ds, 0)) { + err = EINVAL; + break; + } + if (dsl_dataset_feature_is_active(rta->ds, + SPA_FEATURE_REDACTED_DATASETS)) { + err = EALREADY; + break; + + } + } + VERIFY3P(nvlist_next_nvpair(redactnvl, pair), ==, NULL); + if (err != 0) + goto out; + + boolean_t resuming = B_FALSE; + char newredactbook[ZFS_MAX_DATASET_NAME_LEN]; + zfs_bookmark_phys_t bookmark; + + (void) strlcpy(newredactbook, snapname, ZFS_MAX_DATASET_NAME_LEN); + char *c = strchr(newredactbook, '@'); + ASSERT3P(c, !=, NULL); + int n = snprintf(c, ZFS_MAX_DATASET_NAME_LEN - (c - newredactbook), + "#%s", redactbook); + if (n >= ZFS_MAX_DATASET_NAME_LEN - (c - newredactbook)) { + dsl_pool_rele(dp, FTAG); + return (SET_ERROR(ENAMETOOLONG)); + } + err = dsl_bookmark_lookup(dp, newredactbook, NULL, &bookmark); + if (err == 0) { + resuming = B_TRUE; + if (bookmark.zbm_redaction_obj == 0) { + err = EEXIST; + goto out; + } + err = dsl_redaction_list_hold_obj(dp, + bookmark.zbm_redaction_obj, FTAG, &new_rl); + if (err != 0) { + err = EIO; + goto out; + } + dsl_redaction_list_long_hold(dp, new_rl, FTAG); + if (new_rl->rl_phys->rlp_num_snaps != numsnaps) { + err = ESRCH; + goto out; + } + for (int i = 0; i < numsnaps; i++) { + struct redact_thread_arg *rta = &args[i]; + if (!redact_snaps_contains(new_rl->rl_phys->rlp_snaps, + new_rl->rl_phys->rlp_num_snaps, + dsl_dataset_phys(rta->ds)->ds_guid)) { + err = ESRCH; + goto out; + } + } + if (new_rl->rl_phys->rlp_last_blkid == UINT64_MAX && + new_rl->rl_phys->rlp_last_object == UINT64_MAX) { + err = EEXIST; + goto out; + } + dsl_pool_rele(dp, FTAG); + dp = NULL; + } else { + uint64_t *guids = NULL; + if (numsnaps > 0) { + guids = kmem_zalloc(numsnaps * sizeof (uint64_t), + KM_SLEEP); + } + for (int i = 0; i < numsnaps; i++) { + struct redact_thread_arg *rta = &args[i]; + guids[i] = dsl_dataset_phys(rta->ds)->ds_guid; + } + + dsl_pool_rele(dp, FTAG); + dp = NULL; + err = dsl_bookmark_create_redacted(newredactbook, snapname, + numsnaps, guids, FTAG, &new_rl); + kmem_free(guids, numsnaps * sizeof (uint64_t)); + if (err != 0) { + goto out; + } + } + + for (int i = 0; i < numsnaps; i++) { + struct redact_thread_arg *rta = &args[i]; + (void) bqueue_init(&rta->q, zfs_redact_queue_ff, + zfs_redact_queue_length, + offsetof(struct redact_record, ln)); + if (resuming) { + rta->resume.zb_blkid = + new_rl->rl_phys->rlp_last_blkid; + rta->resume.zb_object = + new_rl->rl_phys->rlp_last_object; + } + rta->txg = dsl_dataset_phys(ds)->ds_creation_txg; + (void) thread_create(NULL, 0, redact_traverse_thread, rta, + 0, curproc, TS_RUN, minclsyspri); + } + struct redact_merge_thread_arg rmta = { { {0} } }; + (void) bqueue_init(&rmta.q, zfs_redact_queue_ff, + zfs_redact_queue_length, offsetof(struct redact_record, ln)); + rmta.numsnaps = numsnaps; + rmta.spa = os->os_spa; + rmta.thr_args = args; + (void) thread_create(NULL, 0, redact_merge_thread, &rmta, 0, curproc, + TS_RUN, minclsyspri); + err = perform_redaction(os, new_rl, &rmta); +out: + if (new_rl != NULL) { + dsl_redaction_list_long_rele(new_rl, FTAG); + dsl_redaction_list_rele(new_rl, FTAG); + } + for (int i = 0; i < numsnaps; i++) { + struct redact_thread_arg *rta = &args[i]; + /* + * rta->ds may be NULL if we got an error while filling + * it in. + */ + if (rta->ds != NULL) { + dsl_dataset_long_rele(rta->ds, FTAG); + dsl_dataset_rele_flags(rta->ds, + DS_HOLD_FLAG_DECRYPT, FTAG); + } + } + + if (args != NULL) + kmem_free(args, numsnaps * sizeof (*args)); + if (dp != NULL) + dsl_pool_rele(dp, FTAG); + if (ds != NULL) { + dsl_dataset_long_rele(ds, FTAG); + dsl_dataset_rele_flags(ds, DS_HOLD_FLAG_DECRYPT, FTAG); + } + return (SET_ERROR(err)); + +} |