/* * 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 https://opensource.org/licenses/CDDL-1.0. * 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) 2020, 2021, 2022 by Pawel Jakub Dawidek */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* * Block Cloning design. * * Block Cloning allows to manually clone a file (or a subset of its blocks) * into another (or the same) file by just creating additional references to * the data blocks without copying the data itself. Those references are kept * in the Block Reference Tables (BRTs). * * In many ways this is similar to the existing deduplication, but there are * some important differences: * * - Deduplication is automatic and Block Cloning is not - one has to use a * dedicated system call(s) to clone the given file/blocks. * - Deduplication keeps all data blocks in its table, even those referenced * just once. Block Cloning creates an entry in its tables only when there * are at least two references to the given data block. If the block was * never explicitly cloned or the second to last reference was dropped, * there will be neither space nor performance overhead. * - Deduplication needs data to work - one needs to pass real data to the * write(2) syscall, so hash can be calculated. Block Cloning doesn't require * data, just block pointers to the data, so it is extremely fast, as we pay * neither the cost of reading the data, nor the cost of writing the data - * we operate exclusively on metadata. * - If the D (dedup) bit is not set in the block pointer, it means that * the block is not in the dedup table (DDT) and we won't consult the DDT * when we need to free the block. Block Cloning must be consulted on every * free, because we cannot modify the source BP (eg. by setting something * similar to the D bit), thus we have no hint if the block is in the * Block Reference Table (BRT), so we need to look into the BRT. There is * an optimization in place that allows us to eliminate the majority of BRT * lookups which is described below in the "Minimizing free penalty" section. * - The BRT entry is much smaller than the DDT entry - for BRT we only store * 64bit offset and 64bit reference counter. * - Dedup keys are cryptographic hashes, so two blocks that are close to each * other on disk are most likely in totally different parts of the DDT. * The BRT entry keys are offsets into a single top-level VDEV, so data blocks * from one file should have BRT entries close to each other. * - Scrub will only do a single pass over a block that is referenced multiple * times in the DDT. Unfortunately it is not currently (if at all) possible * with Block Cloning and block referenced multiple times will be scrubbed * multiple times. The new, sorted scrub should be able to eliminate * duplicated reads given enough memory. * - Deduplication requires cryptographically strong hash as a checksum or * additional data verification. Block Cloning works with any checksum * algorithm or even with checksumming disabled. * * As mentioned above, the BRT entries are much smaller than the DDT entries. * To uniquely identify a block we just need its vdev id and offset. We also * need to maintain a reference counter. The vdev id will often repeat, as there * is a small number of top-level VDEVs and a large number of blocks stored in * each VDEV. We take advantage of that to reduce the BRT entry size further by * maintaining one BRT for each top-level VDEV, so we can then have only offset * and counter as the BRT entry. * * Minimizing free penalty. * * Block Cloning allows creating additional references to any existing block. * When we free a block there is no hint in the block pointer whether the block * was cloned or not, so on each free we have to check if there is a * corresponding entry in the BRT or not. If there is, we need to decrease * the reference counter. Doing BRT lookup on every free can potentially be * expensive by requiring additional I/Os if the BRT doesn't fit into memory. * This is the main problem with deduplication, so we've learned our lesson and * try not to repeat the same mistake here. How do we do that? We divide each * top-level VDEV into 16MB regions. For each region we maintain a counter that * is a sum of all the BRT entries that have offsets within the region. This * creates the entries count array of 16bit numbers for each top-level VDEV. * The entries count array is always kept in memory and updated on disk in the * same transaction group as the BRT updates to keep everything in-sync. We can * keep the array in memory, because it is very small. With 16MB regions and * 1TB VDEV the array requires only 128kB of memory (we may decide to decrease * the region size even further in the future). Now, when we want to free * a block, we first consult the array. If the counter for the whole region is * zero, there is no need to look for the BRT entry, as there isn't one for * sure. If the counter for the region is greater than zero, only then we will * do a BRT lookup and if an entry is found we will decrease the reference * counter in the BRT entry and in the entry counters array. * * The entry counters array is small, but can potentially be larger for very * large VDEVs or smaller regions. In this case we don't want to rewrite entire * array on every change. We then divide the array into 32kB block and keep * a bitmap of dirty blocks within a transaction group. When we sync the * transaction group we can only update the parts of the entry counters array * that were modified. Note: Keeping track of the dirty parts of the entry * counters array is implemented, but updating only parts of the array on disk * is not yet implemented - for now we will update entire array if there was * any change. * * The implementation tries to be economic: if BRT is not used, or no longer * used, there will be no entries in the MOS and no additional memory used (eg. * the entry counters array is only allocated if needed). * * Interaction between Deduplication and Block Cloning. * * If both functionalities are in use, we could end up with a block that is * referenced multiple times in both DDT and BRT. When we free one of the * references we couldn't tell where it belongs, so we would have to decide * what table takes the precedence: do we first clear DDT references or BRT * references? To avoid this dilemma BRT cooperates with DDT - if a given block * is being cloned using BRT and the BP has the D (dedup) bit set, BRT will * lookup DDT entry instead and increase the counter there. No BRT entry * will be created for a block which has the D (dedup) bit set. * BRT may be more efficient for manual deduplication, but if the block is * already in the DDT, then creating additional BRT entry would be less * efficient. This clever idea was proposed by Allan Jude. * * Block Cloning across datasets. * * Block Cloning is not limited to cloning blocks within the same dataset. * It is possible (and very useful) to clone blocks between different datasets. * One use case is recovering files from snapshots. By cloning the files into * dataset we need no additional storage. Without Block Cloning we would need * additional space for those files. * Another interesting use case is moving the files between datasets * (copying the file content to the new dataset and removing the source file). * In that case Block Cloning will only be used briefly, because the BRT entries * will be removed when the source is removed. * Note: currently it is not possible to clone blocks between encrypted * datasets, even if those datasets use the same encryption key (this includes * snapshots of encrypted datasets). Cloning blocks between datasets that use * the same keys should be possible and should be implemented in the future. * * Block Cloning flow through ZFS layers. * * Note: Block Cloning can be used both for cloning file system blocks and ZVOL * blocks. As of this writing no interface is implemented that allows for block * cloning within a ZVOL. * FreeBSD and Linux provides copy_file_range(2) system call and we will use it * for blocking cloning. * * ssize_t * copy_file_range(int infd, off_t *inoffp, int outfd, off_t *outoffp, * size_t len, unsigned int flags); * * Even though offsets and length represent bytes, they have to be * block-aligned or we will return an error so the upper layer can * fallback to the generic mechanism that will just copy the data. * Using copy_file_range(2) will call OS-independent zfs_clone_range() function. * This function was implemented based on zfs_write(), but instead of writing * the given data we first read block pointers using the new dmu_read_l0_bps() * function from the source file. Once we have BPs from the source file we call * the dmu_brt_clone() function on the destination file. This function * allocates BPs for us. We iterate over all source BPs. If the given BP is * a hole or an embedded block, we just copy BP as-is. If it points to a real * data we place this BP on a BRT pending list using the brt_pending_add() * function. * * We use this pending list to keep track of all BPs that got new references * within this transaction group. * * Some special cases to consider and how we address them: * - The block we want to clone may have been created within the same * transaction group that we are trying to clone. Such block has no BP * allocated yet, so cannot be immediately cloned. We return EAGAIN. * - The block we want to clone may have been modified within the same * transaction group. We return EAGAIN. * - A block may be cloned multiple times during one transaction group (that's * why pending list is actually a tree and not an append-only list - this * way we can figure out faster if this block is cloned for the first time * in this txg or consecutive time). * - A block may be cloned and freed within the same transaction group * (see dbuf_undirty()). * - A block may be cloned and within the same transaction group the clone * can be cloned again (see dmu_read_l0_bps()). * - A file might have been deleted, but the caller still has a file descriptor * open to this file and clones it. * * When we free a block we have an additional step in the ZIO pipeline where we * call the zio_brt_free() function. We then call the brt_entry_decref() * that loads the corresponding BRT entry (if one exists) and decreases * reference counter. If this is not the last reference we will stop ZIO * pipeline here. If this is the last reference or the block is not in the * BRT, we continue the pipeline and free the block as usual. * * At the beginning of spa_sync() where there can be no more block cloning, * but before issuing frees we call brt_pending_apply(). This function applies * all the new clones to the BRT table - we load BRT entries and update * reference counters. To sync new BRT entries to disk, we use brt_sync() * function. This function will sync all dirty per-top-level-vdev BRTs, * the entry counters arrays, etc. * * Block Cloning and ZIL. * * Every clone operation is divided into chunks (similar to write) and each * chunk is cloned in a separate transaction. The chunk size is determined by * how many BPs we can fit into a single ZIL entry. * Replaying clone operation is different from the regular clone operation, * as when we log clone operations we cannot use the source object - it may * reside on a different dataset, so we log BPs we want to clone. * The ZIL is replayed when we mount the given dataset, not when the pool is * imported. Taking this into account it is possible that the pool is imported * without mounting datasets and the source dataset is destroyed before the * destination dataset is mounted and its ZIL replayed. * To address this situation we leverage zil_claim() mechanism where ZFS will * parse all the ZILs on pool import. When we come across TX_CLONE_RANGE * entries, we will bump reference counters for their BPs in the BRT and then * on mount and ZIL replay we will just attach BPs to the file without * bumping reference counters. * Note it is still possible that after zil_claim() we never mount the * destination, so we never replay its ZIL and we destroy it. This way we would * end up with leaked references in BRT. We address that too as ZFS gives us * a chance to clean this up on dataset destroy (see zil_free_clone_range()). */ /* * BRT - Block Reference Table. */ #define BRT_OBJECT_VDEV_PREFIX "com.fudosecurity:brt:vdev:" /* * We divide each VDEV into 16MB chunks. Each chunk is represented in memory * by a 16bit counter, thus 1TB VDEV requires 128kB of memory: (1TB / 16MB) * 2B * Each element in this array represents how many BRT entries do we have in this * chunk of storage. We always load this entire array into memory and update as * needed. By having it in memory we can quickly tell (during zio_free()) if * there are any BRT entries that we might need to update. * * This value cannot be larger than 16MB, at least as long as we support * 512 byte block sizes. With 512 byte block size we can have exactly * 32768 blocks in 16MB. In 32MB we could have 65536 blocks, which is one too * many for a 16bit counter. */ #define BRT_RANGESIZE (16 * 1024 * 1024) _Static_assert(BRT_RANGESIZE / SPA_MINBLOCKSIZE <= UINT16_MAX, "BRT_RANGESIZE is too large."); /* * We don't want to update the whole structure every time. Maintain bitmap * of dirty blocks within the regions, so that a single bit represents a * block size of entcounts. For example if we have a 1PB vdev then all * entcounts take 128MB of memory ((64TB / 16MB) * 2B). We can divide this * 128MB array of entcounts into 32kB disk blocks, as we don't want to update * the whole 128MB on disk when we have updated only a single entcount. * We maintain a bitmap where each 32kB disk block within 128MB entcounts array * is represented by a single bit. This gives us 4096 bits. A set bit in the * bitmap means that we had a change in at least one of the 16384 entcounts * that reside on a 32kB disk block (32kB / sizeof (uint16_t)). */ #define BRT_BLOCKSIZE (32 * 1024) #define BRT_RANGESIZE_TO_NBLOCKS(size) \ (((size) - 1) / BRT_BLOCKSIZE / sizeof (uint16_t) + 1) #define BRT_LITTLE_ENDIAN 0 #define BRT_BIG_ENDIAN 1 #ifdef _ZFS_LITTLE_ENDIAN #define BRT_NATIVE_BYTEORDER BRT_LITTLE_ENDIAN #define BRT_NON_NATIVE_BYTEORDER BRT_BIG_ENDIAN #else #define BRT_NATIVE_BYTEORDER BRT_BIG_ENDIAN #define BRT_NON_NATIVE_BYTEORDER BRT_LITTLE_ENDIAN #endif typedef struct brt_vdev_phys { uint64_t bvp_mos_entries; uint64_t bvp_size; uint64_t bvp_byteorder; uint64_t bvp_totalcount; uint64_t bvp_rangesize; uint64_t bvp_usedspace; uint64_t bvp_savedspace; } brt_vdev_phys_t; typedef struct brt_vdev { /* * VDEV id. */ uint64_t bv_vdevid; /* * Is the structure initiated? * (bv_entcount and bv_bitmap are allocated?) */ boolean_t bv_initiated; /* * Object number in the MOS for the entcount array and brt_vdev_phys. */ uint64_t bv_mos_brtvdev; /* * Object number in the MOS for the entries table. */ uint64_t bv_mos_entries; /* * Entries to sync. */ avl_tree_t bv_tree; /* * Does the bv_entcount[] array needs byte swapping? */ boolean_t bv_need_byteswap; /* * Number of entries in the bv_entcount[] array. */ uint64_t bv_size; /* * This is the array with BRT entry count per BRT_RANGESIZE. */ uint16_t *bv_entcount; /* * Sum of all bv_entcount[]s. */ uint64_t bv_totalcount; /* * Space on disk occupied by cloned blocks (without compression). */ uint64_t bv_usedspace; /* * How much additional space would be occupied without block cloning. */ uint64_t bv_savedspace; /* * brt_vdev_phys needs updating on disk. */ boolean_t bv_meta_dirty; /* * bv_entcount[] needs updating on disk. */ boolean_t bv_entcount_dirty; /* * bv_entcount[] potentially can be a bit too big to sychronize it all * when we just changed few entcounts. The fields below allow us to * track updates to bv_entcount[] array since the last sync. * A single bit in the bv_bitmap represents as many entcounts as can * fit into a single BRT_BLOCKSIZE. * For example we have 65536 entcounts in the bv_entcount array * (so the whole array is 128kB). We updated bv_entcount[2] and * bv_entcount[5]. In that case only first bit in the bv_bitmap will * be set and we will write only first BRT_BLOCKSIZE out of 128kB. */ ulong_t *bv_bitmap; uint64_t bv_nblocks; } brt_vdev_t; /* * In-core brt */ typedef struct brt { krwlock_t brt_lock; spa_t *brt_spa; #define brt_mos brt_spa->spa_meta_objset uint64_t brt_rangesize; uint64_t brt_usedspace; uint64_t brt_savedspace; avl_tree_t brt_pending_tree[TXG_SIZE]; kmutex_t brt_pending_lock[TXG_SIZE]; /* Sum of all entries across all bv_trees. */ uint64_t brt_nentries; brt_vdev_t *brt_vdevs; uint64_t brt_nvdevs; } brt_t; /* Size of bre_offset / sizeof (uint64_t). */ #define BRT_KEY_WORDS (1) /* * In-core brt entry. * On-disk we use bre_offset as the key and bre_refcount as the value. */ typedef struct brt_entry { uint64_t bre_offset; uint64_t bre_refcount; avl_node_t bre_node; } brt_entry_t; typedef struct brt_pending_entry { blkptr_t bpe_bp; int bpe_count; avl_node_t bpe_node; } brt_pending_entry_t; static kmem_cache_t *brt_entry_cache; static kmem_cache_t *brt_pending_entry_cache; /* * Enable/disable prefetching of BRT entries that we are going to modify. */ int zfs_brt_prefetch = 1; #ifdef ZFS_DEBUG #define BRT_DEBUG(...) do { \ if ((zfs_flags & ZFS_DEBUG_BRT) != 0) { \ __dprintf(B_TRUE, __FILE__, __func__, __LINE__, __VA_ARGS__); \ } \ } while (0) #else #define BRT_DEBUG(...) do { } while (0) #endif int brt_zap_leaf_blockshift = 12; int brt_zap_indirect_blockshift = 12; static kstat_t *brt_ksp; typedef struct brt_stats { kstat_named_t brt_addref_entry_in_memory; kstat_named_t brt_addref_entry_not_on_disk; kstat_named_t brt_addref_entry_on_disk; kstat_named_t brt_addref_entry_read_lost_race; kstat_named_t brt_decref_entry_in_memory; kstat_named_t brt_decref_entry_loaded_from_disk; kstat_named_t brt_decref_entry_not_in_memory; kstat_named_t brt_decref_entry_not_on_disk; kstat_named_t brt_decref_entry_read_lost_race; kstat_named_t brt_decref_entry_still_referenced; kstat_named_t brt_decref_free_data_later; kstat_named_t brt_decref_free_data_now; kstat_named_t brt_decref_no_entry; } brt_stats_t; static brt_stats_t brt_stats = { { "addref_entry_in_memory", KSTAT_DATA_UINT64 }, { "addref_entry_not_on_disk", KSTAT_DATA_UINT64 }, { "addref_entry_on_disk", KSTAT_DATA_UINT64 }, { "addref_entry_read_lost_race", KSTAT_DATA_UINT64 }, { "decref_entry_in_memory", KSTAT_DATA_UINT64 }, { "decref_entry_loaded_from_disk", KSTAT_DATA_UINT64 }, { "decref_entry_not_in_memory", KSTAT_DATA_UINT64 }, { "decref_entry_not_on_disk", KSTAT_DATA_UINT64 }, { "decref_entry_read_lost_race", KSTAT_DATA_UINT64 }, { "decref_entry_still_referenced", KSTAT_DATA_UINT64 }, { "decref_free_data_later", KSTAT_DATA_UINT64 }, { "decref_free_data_now", KSTAT_DATA_UINT64 }, { "decref_no_entry", KSTAT_DATA_UINT64 } }; struct { wmsum_t brt_addref_entry_in_memory; wmsum_t brt_addref_entry_not_on_disk; wmsum_t brt_addref_entry_on_disk; wmsum_t brt_addref_entry_read_lost_race; wmsum_t brt_decref_entry_in_memory; wmsum_t brt_decref_entry_loaded_from_disk; wmsum_t brt_decref_entry_not_in_memory; wmsum_t brt_decref_entry_not_on_disk; wmsum_t brt_decref_entry_read_lost_race; wmsum_t brt_decref_entry_still_referenced; wmsum_t brt_decref_free_data_later; wmsum_t brt_decref_free_data_now; wmsum_t brt_decref_no_entry; } brt_sums; #define BRTSTAT_BUMP(stat) wmsum_add(&brt_sums.stat, 1) static int brt_entry_compare(const void *x1, const void *x2); static int brt_pending_entry_compare(const void *x1, const void *x2); static void brt_rlock(brt_t *brt) { rw_enter(&brt->brt_lock, RW_READER); } static void brt_wlock(brt_t *brt) { rw_enter(&brt->brt_lock, RW_WRITER); } static void brt_unlock(brt_t *brt) { rw_exit(&brt->brt_lock); } static uint16_t brt_vdev_entcount_get(const brt_vdev_t *brtvd, uint64_t idx) { ASSERT3U(idx, <, brtvd->bv_size); if (brtvd->bv_need_byteswap) { return (BSWAP_16(brtvd->bv_entcount[idx])); } else { return (brtvd->bv_entcount[idx]); } } static void brt_vdev_entcount_set(brt_vdev_t *brtvd, uint64_t idx, uint16_t entcnt) { ASSERT3U(idx, <, brtvd->bv_size); if (brtvd->bv_need_byteswap) { brtvd->bv_entcount[idx] = BSWAP_16(entcnt); } else { brtvd->bv_entcount[idx] = entcnt; } } static void brt_vdev_entcount_inc(brt_vdev_t *brtvd, uint64_t idx) { uint16_t entcnt; ASSERT3U(idx, <, brtvd->bv_size); entcnt = brt_vdev_entcount_get(brtvd, idx); ASSERT(entcnt < UINT16_MAX); brt_vdev_entcount_set(brtvd, idx, entcnt + 1); } static void brt_vdev_entcount_dec(brt_vdev_t *brtvd, uint64_t idx) { uint16_t entcnt; ASSERT3U(idx, <, brtvd->bv_size); entcnt = brt_vdev_entcount_get(brtvd, idx); ASSERT(entcnt > 0); brt_vdev_entcount_set(brtvd, idx, entcnt - 1); } #ifdef ZFS_DEBUG static void brt_vdev_dump(brt_t *brt) { brt_vdev_t *brtvd; uint64_t vdevid; if ((zfs_flags & ZFS_DEBUG_BRT) == 0) { return; } if (brt->brt_nvdevs == 0) { zfs_dbgmsg("BRT empty"); return; } zfs_dbgmsg("BRT vdev dump:"); for (vdevid = 0; vdevid < brt->brt_nvdevs; vdevid++) { uint64_t idx; brtvd = &brt->brt_vdevs[vdevid]; zfs_dbgmsg(" vdevid=%llu/%llu meta_dirty=%d entcount_dirty=%d " "size=%llu totalcount=%llu nblocks=%llu bitmapsize=%zu\n", (u_longlong_t)vdevid, (u_longlong_t)brtvd->bv_vdevid, brtvd->bv_meta_dirty, brtvd->bv_entcount_dirty, (u_longlong_t)brtvd->bv_size, (u_longlong_t)brtvd->bv_totalcount, (u_longlong_t)brtvd->bv_nblocks, (size_t)BT_SIZEOFMAP(brtvd->bv_nblocks)); if (brtvd->bv_totalcount > 0) { zfs_dbgmsg(" entcounts:"); for (idx = 0; idx < brtvd->bv_size; idx++) { if (brt_vdev_entcount_get(brtvd, idx) > 0) { zfs_dbgmsg(" [%04llu] %hu", (u_longlong_t)idx, brt_vdev_entcount_get(brtvd, idx)); } } } if (brtvd->bv_entcount_dirty) { char *bitmap; bitmap = kmem_alloc(brtvd->bv_nblocks + 1, KM_SLEEP); for (idx = 0; idx < brtvd->bv_nblocks; idx++) { bitmap[idx] = BT_TEST(brtvd->bv_bitmap, idx) ? 'x' : '.'; } bitmap[idx] = '\0'; zfs_dbgmsg(" bitmap: %s", bitmap); kmem_free(bitmap, brtvd->bv_nblocks + 1); } } } #endif static brt_vdev_t * brt_vdev(brt_t *brt, uint64_t vdevid) { brt_vdev_t *brtvd; ASSERT(RW_LOCK_HELD(&brt->brt_lock)); if (vdevid < brt->brt_nvdevs) { brtvd = &brt->brt_vdevs[vdevid]; } else { brtvd = NULL; } return (brtvd); } static void brt_vdev_create(brt_t *brt, brt_vdev_t *brtvd, dmu_tx_t *tx) { char name[64]; ASSERT(RW_WRITE_HELD(&brt->brt_lock)); ASSERT0(brtvd->bv_mos_brtvdev); ASSERT0(brtvd->bv_mos_entries); ASSERT(brtvd->bv_entcount != NULL); ASSERT(brtvd->bv_size > 0); ASSERT(brtvd->bv_bitmap != NULL); ASSERT(brtvd->bv_nblocks > 0); brtvd->bv_mos_entries = zap_create_flags(brt->brt_mos, 0, ZAP_FLAG_HASH64 | ZAP_FLAG_UINT64_KEY, DMU_OTN_ZAP_METADATA, brt_zap_leaf_blockshift, brt_zap_indirect_blockshift, DMU_OT_NONE, 0, tx); VERIFY(brtvd->bv_mos_entries != 0); BRT_DEBUG("MOS entries created, object=%llu", (u_longlong_t)brtvd->bv_mos_entries); /* * We allocate DMU buffer to store the bv_entcount[] array. * We will keep array size (bv_size) and cummulative count for all * bv_entcount[]s (bv_totalcount) in the bonus buffer. */ brtvd->bv_mos_brtvdev = dmu_object_alloc(brt->brt_mos, DMU_OTN_UINT64_METADATA, BRT_BLOCKSIZE, DMU_OTN_UINT64_METADATA, sizeof (brt_vdev_phys_t), tx); VERIFY(brtvd->bv_mos_brtvdev != 0); BRT_DEBUG("MOS BRT VDEV created, object=%llu", (u_longlong_t)brtvd->bv_mos_brtvdev); snprintf(name, sizeof (name), "%s%llu", BRT_OBJECT_VDEV_PREFIX, (u_longlong_t)brtvd->bv_vdevid); VERIFY0(zap_add(brt->brt_mos, DMU_POOL_DIRECTORY_OBJECT, name, sizeof (uint64_t), 1, &brtvd->bv_mos_brtvdev, tx)); BRT_DEBUG("Pool directory object created, object=%s", name); spa_feature_incr(brt->brt_spa, SPA_FEATURE_BLOCK_CLONING, tx); } static void brt_vdev_realloc(brt_t *brt, brt_vdev_t *brtvd) { vdev_t *vd; uint16_t *entcount; ulong_t *bitmap; uint64_t nblocks, size; ASSERT(RW_WRITE_HELD(&brt->brt_lock)); spa_config_enter(brt->brt_spa, SCL_VDEV, FTAG, RW_READER); vd = vdev_lookup_top(brt->brt_spa, brtvd->bv_vdevid); size = (vdev_get_min_asize(vd) - 1) / brt->brt_rangesize + 1; spa_config_exit(brt->brt_spa, SCL_VDEV, FTAG); entcount = vmem_zalloc(sizeof (entcount[0]) * size, KM_SLEEP); nblocks = BRT_RANGESIZE_TO_NBLOCKS(size); bitmap = kmem_zalloc(BT_SIZEOFMAP(nblocks), KM_SLEEP); if (!brtvd->bv_initiated) { ASSERT0(brtvd->bv_size); ASSERT(brtvd->bv_entcount == NULL); ASSERT(brtvd->bv_bitmap == NULL); ASSERT0(brtvd->bv_nblocks); avl_create(&brtvd->bv_tree, brt_entry_compare, sizeof (brt_entry_t), offsetof(brt_entry_t, bre_node)); } else { ASSERT(brtvd->bv_size > 0); ASSERT(brtvd->bv_entcount != NULL); ASSERT(brtvd->bv_bitmap != NULL); ASSERT(brtvd->bv_nblocks > 0); /* * TODO: Allow vdev shrinking. We only need to implement * shrinking the on-disk BRT VDEV object. * dmu_free_range(brt->brt_mos, brtvd->bv_mos_brtvdev, offset, * size, tx); */ ASSERT3U(brtvd->bv_size, <=, size); memcpy(entcount, brtvd->bv_entcount, sizeof (entcount[0]) * MIN(size, brtvd->bv_size)); memcpy(bitmap, brtvd->bv_bitmap, MIN(BT_SIZEOFMAP(nblocks), BT_SIZEOFMAP(brtvd->bv_nblocks))); vmem_free(brtvd->bv_entcount, sizeof (entcount[0]) * brtvd->bv_size); kmem_free(brtvd->bv_bitmap, BT_SIZEOFMAP(brtvd->bv_nblocks)); } brtvd->bv_size = size; brtvd->bv_entcount = entcount; brtvd->bv_bitmap = bitmap; brtvd->bv_nblocks = nblocks; if (!brtvd->bv_initiated) { brtvd->bv_need_byteswap = FALSE; brtvd->bv_initiated = TRUE; BRT_DEBUG("BRT VDEV %llu initiated.", (u_longlong_t)brtvd->bv_vdevid); } } static void brt_vdev_load(brt_t *brt, brt_vdev_t *brtvd) { char name[64]; dmu_buf_t *db; brt_vdev_phys_t *bvphys; int error; snprintf(name, sizeof (name), "%s%llu", BRT_OBJECT_VDEV_PREFIX, (u_longlong_t)brtvd->bv_vdevid); error = zap_lookup(brt->brt_mos, DMU_POOL_DIRECTORY_OBJECT, name, sizeof (uint64_t), 1, &brtvd->bv_mos_brtvdev); if (error != 0) return; ASSERT(brtvd->bv_mos_brtvdev != 0); error = dmu_bonus_hold(brt->brt_mos, brtvd->bv_mos_brtvdev, FTAG, &db); ASSERT0(error); if (error != 0) return; bvphys = db->db_data; if (brt->brt_rangesize == 0) { brt->brt_rangesize = bvphys->bvp_rangesize; } else { ASSERT3U(brt->brt_rangesize, ==, bvphys->bvp_rangesize); } ASSERT(!brtvd->bv_initiated); brt_vdev_realloc(brt, brtvd); /* TODO: We don't support VDEV shrinking. */ ASSERT3U(bvphys->bvp_size, <=, brtvd->bv_size); /* * If VDEV grew, we will leave new bv_entcount[] entries zeroed out. */ error = dmu_read(brt->brt_mos, brtvd->bv_mos_brtvdev, 0, MIN(brtvd->bv_size, bvphys->bvp_size) * sizeof (uint16_t), brtvd->bv_entcount, DMU_READ_NO_PREFETCH); ASSERT0(error); brtvd->bv_mos_entries = bvphys->bvp_mos_entries; ASSERT(brtvd->bv_mos_entries != 0); brtvd->bv_need_byteswap = (bvphys->bvp_byteorder != BRT_NATIVE_BYTEORDER); brtvd->bv_totalcount = bvphys->bvp_totalcount; brtvd->bv_usedspace = bvphys->bvp_usedspace; brtvd->bv_savedspace = bvphys->bvp_savedspace; brt->brt_usedspace += brtvd->bv_usedspace; brt->brt_savedspace += brtvd->bv_savedspace; dmu_buf_rele(db, FTAG); BRT_DEBUG("MOS BRT VDEV %s loaded: mos_brtvdev=%llu, mos_entries=%llu", name, (u_longlong_t)brtvd->bv_mos_brtvdev, (u_longlong_t)brtvd->bv_mos_entries); } static void brt_vdev_dealloc(brt_t *brt, brt_vdev_t *brtvd) { ASSERT(RW_WRITE_HELD(&brt->brt_lock)); ASSERT(brtvd->bv_initiated); vmem_free(brtvd->bv_entcount, sizeof (uint16_t) * brtvd->bv_size); brtvd->bv_entcount = NULL; kmem_free(brtvd->bv_bitmap, BT_SIZEOFMAP(brtvd->bv_nblocks)); brtvd->bv_bitmap = NULL; ASSERT0(avl_numnodes(&brtvd->bv_tree)); avl_destroy(&brtvd->bv_tree); brtvd->bv_size = 0; brtvd->bv_nblocks = 0; brtvd->bv_initiated = FALSE; BRT_DEBUG("BRT VDEV %llu deallocated.", (u_longlong_t)brtvd->bv_vdevid); } static void brt_vdev_destroy(brt_t *brt, brt_vdev_t *brtvd, dmu_tx_t *tx) { char name[64]; uint64_t count; dmu_buf_t *db; brt_vdev_phys_t *bvphys; ASSERT(RW_WRITE_HELD(&brt->brt_lock)); ASSERT(brtvd->bv_mos_brtvdev != 0); ASSERT(brtvd->bv_mos_entries != 0); VERIFY0(zap_count(brt->brt_mos, brtvd->bv_mos_entries, &count)); VERIFY0(count); VERIFY0(zap_destroy(brt->brt_mos, brtvd->bv_mos_entries, tx)); BRT_DEBUG("MOS entries destroyed, object=%llu", (u_longlong_t)brtvd->bv_mos_entries); brtvd->bv_mos_entries = 0; VERIFY0(dmu_bonus_hold(brt->brt_mos, brtvd->bv_mos_brtvdev, FTAG, &db)); bvphys = db->db_data; ASSERT0(bvphys->bvp_totalcount); ASSERT0(bvphys->bvp_usedspace); ASSERT0(bvphys->bvp_savedspace); dmu_buf_rele(db, FTAG); VERIFY0(dmu_object_free(brt->brt_mos, brtvd->bv_mos_brtvdev, tx)); BRT_DEBUG("MOS BRT VDEV destroyed, object=%llu", (u_longlong_t)brtvd->bv_mos_brtvdev); brtvd->bv_mos_brtvdev = 0; snprintf(name, sizeof (name), "%s%llu", BRT_OBJECT_VDEV_PREFIX, (u_longlong_t)brtvd->bv_vdevid); VERIFY0(zap_remove(brt->brt_mos, DMU_POOL_DIRECTORY_OBJECT, name, tx)); BRT_DEBUG("Pool directory object removed, object=%s", name); brt_vdev_dealloc(brt, brtvd); spa_feature_decr(brt->brt_spa, SPA_FEATURE_BLOCK_CLONING, tx); } static void brt_vdevs_expand(brt_t *brt, uint64_t nvdevs) { brt_vdev_t *brtvd, *vdevs; uint64_t vdevid; ASSERT(RW_WRITE_HELD(&brt->brt_lock)); ASSERT3U(nvdevs, >, brt->brt_nvdevs); vdevs = kmem_zalloc(sizeof (vdevs[0]) * nvdevs, KM_SLEEP); if (brt->brt_nvdevs > 0) { ASSERT(brt->brt_vdevs != NULL); memcpy(vdevs, brt->brt_vdevs, sizeof (brt_vdev_t) * brt->brt_nvdevs); kmem_free(brt->brt_vdevs, sizeof (brt_vdev_t) * brt->brt_nvdevs); } for (vdevid = brt->brt_nvdevs; vdevid < nvdevs; vdevid++) { brtvd = &vdevs[vdevid]; brtvd->bv_vdevid = vdevid; brtvd->bv_initiated = FALSE; } BRT_DEBUG("BRT VDEVs expanded from %llu to %llu.", (u_longlong_t)brt->brt_nvdevs, (u_longlong_t)nvdevs); brt->brt_vdevs = vdevs; brt->brt_nvdevs = nvdevs; } static boolean_t brt_vdev_lookup(brt_t *brt, brt_vdev_t *brtvd, const brt_entry_t *bre) { uint64_t idx; ASSERT(RW_LOCK_HELD(&brt->brt_lock)); idx = bre->bre_offset / brt->brt_rangesize; if (brtvd->bv_entcount != NULL && idx < brtvd->bv_size) { /* VDEV wasn't expanded. */ return (brt_vdev_entcount_get(brtvd, idx) > 0); } return (FALSE); } static void brt_vdev_addref(brt_t *brt, brt_vdev_t *brtvd, const brt_entry_t *bre, uint64_t dsize) { uint64_t idx; ASSERT(RW_LOCK_HELD(&brt->brt_lock)); ASSERT(brtvd != NULL); ASSERT(brtvd->bv_entcount != NULL); brt->brt_savedspace += dsize; brtvd->bv_savedspace += dsize; brtvd->bv_meta_dirty = TRUE; if (bre->bre_refcount > 1) { return; } brt->brt_usedspace += dsize; brtvd->bv_usedspace += dsize; idx = bre->bre_offset / brt->brt_rangesize; if (idx >= brtvd->bv_size) { /* VDEV has been expanded. */ brt_vdev_realloc(brt, brtvd); } ASSERT3U(idx, <, brtvd->bv_size); brtvd->bv_totalcount++; brt_vdev_entcount_inc(brtvd, idx); brtvd->bv_entcount_dirty = TRUE; idx = idx / BRT_BLOCKSIZE / 8; BT_SET(brtvd->bv_bitmap, idx); #ifdef ZFS_DEBUG brt_vdev_dump(brt); #endif } static void brt_vdev_decref(brt_t *brt, brt_vdev_t *brtvd, const brt_entry_t *bre, uint64_t dsize) { uint64_t idx; ASSERT(RW_WRITE_HELD(&brt->brt_lock)); ASSERT(brtvd != NULL); ASSERT(brtvd->bv_entcount != NULL); brt->brt_savedspace -= dsize; brtvd->bv_savedspace -= dsize; brtvd->bv_meta_dirty = TRUE; if (bre->bre_refcount > 0) { return; } brt->brt_usedspace -= dsize; brtvd->bv_usedspace -= dsize; idx = bre->bre_offset / brt->brt_rangesize; ASSERT3U(idx, <, brtvd->bv_size); ASSERT(brtvd->bv_totalcount > 0); brtvd->bv_totalcount--; brt_vdev_entcount_dec(brtvd, idx); brtvd->bv_entcount_dirty = TRUE; idx = idx / BRT_BLOCKSIZE / 8; BT_SET(brtvd->bv_bitmap, idx); #ifdef ZFS_DEBUG brt_vdev_dump(brt); #endif } static void brt_vdev_sync(brt_t *brt, brt_vdev_t *brtvd, dmu_tx_t *tx) { dmu_buf_t *db; brt_vdev_phys_t *bvphys; ASSERT(brtvd->bv_meta_dirty); ASSERT(brtvd->bv_mos_brtvdev != 0); ASSERT(dmu_tx_is_syncing(tx)); VERIFY0(dmu_bonus_hold(brt->brt_mos, brtvd->bv_mos_brtvdev, FTAG, &db)); if (brtvd->bv_entcount_dirty) { /* * TODO: Walk brtvd->bv_bitmap and write only the dirty blocks. */ dmu_write(brt->brt_mos, brtvd->bv_mos_brtvdev, 0, brtvd->bv_size * sizeof (brtvd->bv_entcount[0]), brtvd->bv_entcount, tx); memset(brtvd->bv_bitmap, 0, BT_SIZEOFMAP(brtvd->bv_nblocks)); brtvd->bv_entcount_dirty = FALSE; } dmu_buf_will_dirty(db, tx); bvphys = db->db_data; bvphys->bvp_mos_entries = brtvd->bv_mos_entries; bvphys->bvp_size = brtvd->bv_size; if (brtvd->bv_need_byteswap) { bvphys->bvp_byteorder = BRT_NON_NATIVE_BYTEORDER; } else { bvphys->bvp_byteorder = BRT_NATIVE_BYTEORDER; } bvphys->bvp_totalcount = brtvd->bv_totalcount; bvphys->bvp_rangesize = brt->brt_rangesize; bvphys->bvp_usedspace = brtvd->bv_usedspace; bvphys->bvp_savedspace = brtvd->bv_savedspace; dmu_buf_rele(db, FTAG); brtvd->bv_meta_dirty = FALSE; } static void brt_vdevs_alloc(brt_t *brt, boolean_t load) { brt_vdev_t *brtvd; uint64_t vdevid; brt_wlock(brt); brt_vdevs_expand(brt, brt->brt_spa->spa_root_vdev->vdev_children); if (load) { for (vdevid = 0; vdevid < brt->brt_nvdevs; vdevid++) { brtvd = &brt->brt_vdevs[vdevid]; ASSERT(brtvd->bv_entcount == NULL); brt_vdev_load(brt, brtvd); } } if (brt->brt_rangesize == 0) { brt->brt_rangesize = BRT_RANGESIZE; } brt_unlock(brt); } static void brt_vdevs_free(brt_t *brt) { brt_vdev_t *brtvd; uint64_t vdevid; brt_wlock(brt); for (vdevid = 0; vdevid < brt->brt_nvdevs; vdevid++) { brtvd = &brt->brt_vdevs[vdevid]; if (brtvd->bv_initiated) brt_vdev_dealloc(brt, brtvd); } kmem_free(brt->brt_vdevs, sizeof (brt_vdev_t) * brt->brt_nvdevs); brt_unlock(brt); } static void brt_entry_fill(const blkptr_t *bp, brt_entry_t *bre, uint64_t *vdevidp) { bre->bre_offset = DVA_GET_OFFSET(&bp->blk_dva[0]); bre->bre_refcount = 0; *vdevidp = DVA_GET_VDEV(&bp->blk_dva[0]); } static int brt_entry_compare(const void *x1, const void *x2) { const brt_entry_t *bre1 = x1; const brt_entry_t *bre2 = x2; return (TREE_CMP(bre1->bre_offset, bre2->bre_offset)); } static int brt_entry_lookup(brt_t *brt, brt_vdev_t *brtvd, brt_entry_t *bre) { uint64_t mos_entries; uint64_t one, physsize; int error; ASSERT(RW_LOCK_HELD(&brt->brt_lock)); if (!brt_vdev_lookup(brt, brtvd, bre)) return (SET_ERROR(ENOENT)); /* * Remember mos_entries object number. After we reacquire the BRT lock, * the brtvd pointer may be invalid. */ mos_entries = brtvd->bv_mos_entries; if (mos_entries == 0) return (SET_ERROR(ENOENT)); brt_unlock(brt); error = zap_length_uint64(brt->brt_mos, mos_entries, &bre->bre_offset, BRT_KEY_WORDS, &one, &physsize); if (error == 0) { ASSERT3U(one, ==, 1); ASSERT3U(physsize, ==, sizeof (bre->bre_refcount)); error = zap_lookup_uint64(brt->brt_mos, mos_entries, &bre->bre_offset, BRT_KEY_WORDS, 1, sizeof (bre->bre_refcount), &bre->bre_refcount); BRT_DEBUG("ZAP lookup: object=%llu vdev=%llu offset=%llu " "count=%llu error=%d", (u_longlong_t)mos_entries, (u_longlong_t)brtvd->bv_vdevid, (u_longlong_t)bre->bre_offset, error == 0 ? (u_longlong_t)bre->bre_refcount : 0, error); } brt_wlock(brt); return (error); } static void brt_entry_prefetch(brt_t *brt, uint64_t vdevid, brt_entry_t *bre) { brt_vdev_t *brtvd; uint64_t mos_entries = 0; brt_rlock(brt); brtvd = brt_vdev(brt, vdevid); if (brtvd != NULL) mos_entries = brtvd->bv_mos_entries; brt_unlock(brt); if (mos_entries == 0) return; BRT_DEBUG("ZAP prefetch: object=%llu vdev=%llu offset=%llu", (u_longlong_t)mos_entries, (u_longlong_t)vdevid, (u_longlong_t)bre->bre_offset); (void) zap_prefetch_uint64(brt->brt_mos, mos_entries, (uint64_t *)&bre->bre_offset, BRT_KEY_WORDS); } static int brt_entry_update(brt_t *brt, brt_vdev_t *brtvd, brt_entry_t *bre, dmu_tx_t *tx) { int error; ASSERT(RW_LOCK_HELD(&brt->brt_lock)); ASSERT(brtvd->bv_mos_entries != 0); ASSERT(bre->bre_refcount > 0); error = zap_update_uint64(brt->brt_mos, brtvd->bv_mos_entries, (uint64_t *)&bre->bre_offset, BRT_KEY_WORDS, 1, sizeof (bre->bre_refcount), &bre->bre_refcount, tx); BRT_DEBUG("ZAP update: object=%llu vdev=%llu offset=%llu count=%llu " "error=%d", (u_longlong_t)brtvd->bv_mos_entries, (u_longlong_t)brtvd->bv_vdevid, (u_longlong_t)bre->bre_offset, (u_longlong_t)bre->bre_refcount, error); return (error); } static int brt_entry_remove(brt_t *brt, brt_vdev_t *brtvd, brt_entry_t *bre, dmu_tx_t *tx) { int error; ASSERT(RW_LOCK_HELD(&brt->brt_lock)); ASSERT(brtvd->bv_mos_entries != 0); ASSERT0(bre->bre_refcount); error = zap_remove_uint64(brt->brt_mos, brtvd->bv_mos_entries, (uint64_t *)&bre->bre_offset, BRT_KEY_WORDS, tx); BRT_DEBUG("ZAP remove: object=%llu vdev=%llu offset=%llu count=%llu " "error=%d", (u_longlong_t)brtvd->bv_mos_entries, (u_longlong_t)brtvd->bv_vdevid, (u_longlong_t)bre->bre_offset, (u_longlong_t)bre->bre_refcount, error); return (error); } /* * Return TRUE if we _can_ have BRT entry for this bp. It might be false * positive, but gives us quick answer if we should look into BRT, which * may require reads and thus will be more expensive. */ boolean_t brt_maybe_exists(spa_t *spa, const blkptr_t *bp) { brt_t *brt = spa->spa_brt; brt_vdev_t *brtvd; brt_entry_t bre_search; boolean_t mayexists = FALSE; uint64_t vdevid; brt_entry_fill(bp, &bre_search, &vdevid); brt_rlock(brt); brtvd = brt_vdev(brt, vdevid); if (brtvd != NULL && brtvd->bv_initiated) { if (!avl_is_empty(&brtvd->bv_tree) || brt_vdev_lookup(brt, brtvd, &bre_search)) { mayexists = TRUE; } } brt_unlock(brt); return (mayexists); } uint64_t brt_get_dspace(spa_t *spa) { brt_t *brt = spa->spa_brt; if (brt == NULL) return (0); return (brt->brt_savedspace); } uint64_t brt_get_used(spa_t *spa) { brt_t *brt = spa->spa_brt; if (brt == NULL) return (0); return (brt->brt_usedspace); } uint64_t brt_get_saved(spa_t *spa) { brt_t *brt = spa->spa_brt; if (brt == NULL) return (0); return (brt->brt_savedspace); } uint64_t brt_get_ratio(spa_t *spa) { brt_t *brt = spa->spa_brt; if (brt->brt_usedspace == 0) return (100); return ((brt->brt_usedspace + brt->brt_savedspace) * 100 / brt->brt_usedspace); } static int brt_kstats_update(kstat_t *ksp, int rw) { brt_stats_t *bs = ksp->ks_data; if (rw == KSTAT_WRITE) return (EACCES); bs->brt_addref_entry_in_memory.value.ui64 = wmsum_value(&brt_sums.brt_addref_entry_in_memory); bs->brt_addref_entry_not_on_disk.value.ui64 = wmsum_value(&brt_sums.brt_addref_entry_not_on_disk); bs->brt_addref_entry_on_disk.value.ui64 = wmsum_value(&brt_sums.brt_addref_entry_on_disk); bs->brt_addref_entry_read_lost_race.value.ui64 = wmsum_value(&brt_sums.brt_addref_entry_read_lost_race); bs->brt_decref_entry_in_memory.value.ui64 = wmsum_value(&brt_sums.brt_decref_entry_in_memory); bs->brt_decref_entry_loaded_from_disk.value.ui64 = wmsum_value(&brt_sums.brt_decref_entry_loaded_from_disk); bs->brt_decref_entry_not_in_memory.value.ui64 = wmsum_value(&brt_sums.brt_decref_entry_not_in_memory); bs->brt_decref_entry_not_on_disk.value.ui64 = wmsum_value(&brt_sums.brt_decref_entry_not_on_disk); bs->brt_decref_entry_read_lost_race.value.ui64 = wmsum_value(&brt_sums.brt_decref_entry_read_lost_race); bs->brt_decref_entry_still_referenced.value.ui64 = wmsum_value(&brt_sums.brt_decref_entry_still_referenced); bs->brt_decref_free_data_later.value.ui64 = wmsum_value(&brt_sums.brt_decref_free_data_later); bs->brt_decref_free_data_now.value.ui64 = wmsum_value(&brt_sums.brt_decref_free_data_now); bs->brt_decref_no_entry.value.ui64 = wmsum_value(&brt_sums.brt_decref_no_entry); return (0); } static void brt_stat_init(void) { wmsum_init(&brt_sums.brt_addref_entry_in_memory, 0); wmsum_init(&brt_sums.brt_addref_entry_not_on_disk, 0); wmsum_init(&brt_sums.brt_addref_entry_on_disk, 0); wmsum_init(&brt_sums.brt_addref_entry_read_lost_race, 0); wmsum_init(&brt_sums.brt_decref_entry_in_memory, 0); wmsum_init(&brt_sums.brt_decref_entry_loaded_from_disk, 0); wmsum_init(&brt_sums.brt_decref_entry_not_in_memory, 0); wmsum_init(&brt_sums.brt_decref_entry_not_on_disk, 0); wmsum_init(&brt_sums.brt_decref_entry_read_lost_race, 0); wmsum_init(&brt_sums.brt_decref_entry_still_referenced, 0); wmsum_init(&brt_sums.brt_decref_free_data_later, 0); wmsum_init(&brt_sums.brt_decref_free_data_now, 0); wmsum_init(&brt_sums.brt_decref_no_entry, 0); brt_ksp = kstat_create("zfs", 0, "brtstats", "misc", KSTAT_TYPE_NAMED, sizeof (brt_stats) / sizeof (kstat_named_t), KSTAT_FLAG_VIRTUAL); if (brt_ksp != NULL) { brt_ksp->ks_data = &brt_stats; brt_ksp->ks_update = brt_kstats_update; kstat_install(brt_ksp); } } static void brt_stat_fini(void) { if (brt_ksp != NULL) { kstat_delete(brt_ksp); brt_ksp = NULL; } wmsum_fini(&brt_sums.brt_addref_entry_in_memory); wmsum_fini(&brt_sums.brt_addref_entry_not_on_disk); wmsum_fini(&brt_sums.brt_addref_entry_on_disk); wmsum_fini(&brt_sums.brt_addref_entry_read_lost_race); wmsum_fini(&brt_sums.brt_decref_entry_in_memory); wmsum_fini(&brt_sums.brt_decref_entry_loaded_from_disk); wmsum_fini(&brt_sums.brt_decref_entry_not_in_memory); wmsum_fini(&brt_sums.brt_decref_entry_not_on_disk); wmsum_fini(&brt_sums.brt_decref_entry_read_lost_race); wmsum_fini(&brt_sums.brt_decref_entry_still_referenced); wmsum_fini(&brt_sums.brt_decref_free_data_later); wmsum_fini(&brt_sums.brt_decref_free_data_now); wmsum_fini(&brt_sums.brt_decref_no_entry); } void brt_init(void) { brt_entry_cache = kmem_cache_create("brt_entry_cache", sizeof (brt_entry_t), 0, NULL, NULL, NULL, NULL, NULL, 0); brt_pending_entry_cache = kmem_cache_create("brt_pending_entry_cache", sizeof (brt_pending_entry_t), 0, NULL, NULL, NULL, NULL, NULL, 0); brt_stat_init(); } void brt_fini(void) { brt_stat_fini(); kmem_cache_destroy(brt_entry_cache); kmem_cache_destroy(brt_pending_entry_cache); } static brt_entry_t * brt_entry_alloc(const brt_entry_t *bre_init) { brt_entry_t *bre; bre = kmem_cache_alloc(brt_entry_cache, KM_SLEEP); bre->bre_offset = bre_init->bre_offset; bre->bre_refcount = bre_init->bre_refcount; return (bre); } static void brt_entry_free(brt_entry_t *bre) { kmem_cache_free(brt_entry_cache, bre); } static void brt_entry_addref(brt_t *brt, const blkptr_t *bp) { brt_vdev_t *brtvd; brt_entry_t *bre, *racebre; brt_entry_t bre_search; avl_index_t where; uint64_t vdevid; int error; ASSERT(!RW_WRITE_HELD(&brt->brt_lock)); brt_entry_fill(bp, &bre_search, &vdevid); brt_wlock(brt); brtvd = brt_vdev(brt, vdevid); if (brtvd == NULL) { ASSERT3U(vdevid, >=, brt->brt_nvdevs); /* New VDEV was added. */ brt_vdevs_expand(brt, vdevid + 1); brtvd = brt_vdev(brt, vdevid); } ASSERT(brtvd != NULL); if (!brtvd->bv_initiated) brt_vdev_realloc(brt, brtvd); bre = avl_find(&brtvd->bv_tree, &bre_search, NULL); if (bre != NULL) { BRTSTAT_BUMP(brt_addref_entry_in_memory); } else { /* * brt_entry_lookup() may drop the BRT (read) lock and * reacquire it (write). */ error = brt_entry_lookup(brt, brtvd, &bre_search); /* bre_search now contains correct bre_refcount */ ASSERT(error == 0 || error == ENOENT); if (error == 0) BRTSTAT_BUMP(brt_addref_entry_on_disk); else BRTSTAT_BUMP(brt_addref_entry_not_on_disk); /* * When the BRT lock was dropped, brt_vdevs[] may have been * expanded and reallocated, we need to update brtvd's pointer. */ brtvd = brt_vdev(brt, vdevid); ASSERT(brtvd != NULL); racebre = avl_find(&brtvd->bv_tree, &bre_search, &where); if (racebre == NULL) { bre = brt_entry_alloc(&bre_search); ASSERT(RW_WRITE_HELD(&brt->brt_lock)); avl_insert(&brtvd->bv_tree, bre, where); brt->brt_nentries++; } else { /* * The entry was added when the BRT lock was dropped in * brt_entry_lookup(). */ BRTSTAT_BUMP(brt_addref_entry_read_lost_race); bre = racebre; } } bre->bre_refcount++; brt_vdev_addref(brt, brtvd, bre, bp_get_dsize(brt->brt_spa, bp)); brt_unlock(brt); } /* Return TRUE if block should be freed immediately. */ boolean_t brt_entry_decref(spa_t *spa, const blkptr_t *bp) { brt_t *brt = spa->spa_brt; brt_vdev_t *brtvd; brt_entry_t *bre, *racebre; brt_entry_t bre_search; avl_index_t where; uint64_t vdevid; int error; brt_entry_fill(bp, &bre_search, &vdevid); brt_wlock(brt); brtvd = brt_vdev(brt, vdevid); ASSERT(brtvd != NULL); bre = avl_find(&brtvd->bv_tree, &bre_search, NULL); if (bre != NULL) { BRTSTAT_BUMP(brt_decref_entry_in_memory); goto out; } else { BRTSTAT_BUMP(brt_decref_entry_not_in_memory); } /* * brt_entry_lookup() may drop the BRT lock and reacquire it. */ error = brt_entry_lookup(brt, brtvd, &bre_search); /* bre_search now contains correct bre_refcount */ ASSERT(error == 0 || error == ENOENT); /* * When the BRT lock was dropped, brt_vdevs[] may have been expanded * and reallocated, we need to update brtvd's pointer. */ brtvd = brt_vdev(brt, vdevid); ASSERT(brtvd != NULL); if (error == ENOENT) { BRTSTAT_BUMP(brt_decref_entry_not_on_disk); bre = NULL; goto out; } racebre = avl_find(&brtvd->bv_tree, &bre_search, &where); if (racebre != NULL) { /* * The entry was added when the BRT lock was dropped in * brt_entry_lookup(). */ BRTSTAT_BUMP(brt_decref_entry_read_lost_race); bre = racebre; goto out; } BRTSTAT_BUMP(brt_decref_entry_loaded_from_disk); bre = brt_entry_alloc(&bre_search); ASSERT(RW_WRITE_HELD(&brt->brt_lock)); avl_insert(&brtvd->bv_tree, bre, where); brt->brt_nentries++; out: if (bre == NULL) { /* * This is a free of a regular (not cloned) block. */ brt_unlock(brt); BRTSTAT_BUMP(brt_decref_no_entry); return (B_TRUE); } if (bre->bre_refcount == 0) { brt_unlock(brt); BRTSTAT_BUMP(brt_decref_free_data_now); return (B_TRUE); } ASSERT(bre->bre_refcount > 0); bre->bre_refcount--; if (bre->bre_refcount == 0) BRTSTAT_BUMP(brt_decref_free_data_later); else BRTSTAT_BUMP(brt_decref_entry_still_referenced); brt_vdev_decref(brt, brtvd, bre, bp_get_dsize(brt->brt_spa, bp)); brt_unlock(brt); return (B_FALSE); } uint64_t brt_entry_get_refcount(spa_t *spa, const blkptr_t *bp) { brt_t *brt = spa->spa_brt; brt_vdev_t *brtvd; brt_entry_t bre_search, *bre; uint64_t vdevid, refcnt; int error; brt_entry_fill(bp, &bre_search, &vdevid); brt_rlock(brt); brtvd = brt_vdev(brt, vdevid); ASSERT(brtvd != NULL); bre = avl_find(&brtvd->bv_tree, &bre_search, NULL); if (bre == NULL) { error = brt_entry_lookup(brt, brtvd, &bre_search); ASSERT(error == 0 || error == ENOENT); if (error == ENOENT) refcnt = 0; else refcnt = bre_search.bre_refcount; } else refcnt = bre->bre_refcount; brt_unlock(brt); return (refcnt); } static void brt_prefetch(brt_t *brt, const blkptr_t *bp) { brt_entry_t bre; uint64_t vdevid; ASSERT(bp != NULL); if (!zfs_brt_prefetch) return; brt_entry_fill(bp, &bre, &vdevid); brt_entry_prefetch(brt, vdevid, &bre); } static int brt_pending_entry_compare(const void *x1, const void *x2) { const brt_pending_entry_t *bpe1 = x1, *bpe2 = x2; const blkptr_t *bp1 = &bpe1->bpe_bp, *bp2 = &bpe2->bpe_bp; int cmp; cmp = TREE_CMP(BP_PHYSICAL_BIRTH(bp1), BP_PHYSICAL_BIRTH(bp2)); if (cmp == 0) { cmp = TREE_CMP(DVA_GET_VDEV(&bp1->blk_dva[0]), DVA_GET_VDEV(&bp2->blk_dva[0])); if (cmp == 0) { cmp = TREE_CMP(DVA_GET_OFFSET(&bp1->blk_dva[0]), DVA_GET_OFFSET(&bp2->blk_dva[0])); } } return (cmp); } void brt_pending_add(spa_t *spa, const blkptr_t *bp, dmu_tx_t *tx) { brt_t *brt; avl_tree_t *pending_tree; kmutex_t *pending_lock; brt_pending_entry_t *bpe, *newbpe; avl_index_t where; uint64_t txg; brt = spa->spa_brt; txg = dmu_tx_get_txg(tx); ASSERT3U(txg, !=, 0); pending_tree = &brt->brt_pending_tree[txg & TXG_MASK]; pending_lock = &brt->brt_pending_lock[txg & TXG_MASK]; newbpe = kmem_cache_alloc(brt_pending_entry_cache, KM_SLEEP); newbpe->bpe_bp = *bp; newbpe->bpe_count = 1; mutex_enter(pending_lock); bpe = avl_find(pending_tree, newbpe, &where); if (bpe == NULL) { avl_insert(pending_tree, newbpe, where); newbpe = NULL; } else { bpe->bpe_count++; } mutex_exit(pending_lock); if (newbpe != NULL) { ASSERT(bpe != NULL); ASSERT(bpe != newbpe); kmem_cache_free(brt_pending_entry_cache, newbpe); } else { ASSERT(bpe == NULL); } /* Prefetch BRT entry, as we will need it in the syncing context. */ brt_prefetch(brt, bp); } void brt_pending_remove(spa_t *spa, const blkptr_t *bp, dmu_tx_t *tx) { brt_t *brt; avl_tree_t *pending_tree; kmutex_t *pending_lock; brt_pending_entry_t *bpe, bpe_search; uint64_t txg; brt = spa->spa_brt; txg = dmu_tx_get_txg(tx); ASSERT3U(txg, !=, 0); pending_tree = &brt->brt_pending_tree[txg & TXG_MASK]; pending_lock = &brt->brt_pending_lock[txg & TXG_MASK]; bpe_search.bpe_bp = *bp; mutex_enter(pending_lock); bpe = avl_find(pending_tree, &bpe_search, NULL); /* I believe we should always find bpe when this function is called. */ if (bpe != NULL) { ASSERT(bpe->bpe_count > 0); bpe->bpe_count--; if (bpe->bpe_count == 0) { avl_remove(pending_tree, bpe); kmem_cache_free(brt_pending_entry_cache, bpe); } } mutex_exit(pending_lock); } void brt_pending_apply(spa_t *spa, uint64_t txg) { brt_t *brt; brt_pending_entry_t *bpe; avl_tree_t *pending_tree; kmutex_t *pending_lock; void *c; ASSERT3U(txg, !=, 0); brt = spa->spa_brt; pending_tree = &brt->brt_pending_tree[txg & TXG_MASK]; pending_lock = &brt->brt_pending_lock[txg & TXG_MASK]; mutex_enter(pending_lock); c = NULL; while ((bpe = avl_destroy_nodes(pending_tree, &c)) != NULL) { boolean_t added_to_ddt; mutex_exit(pending_lock); for (int i = 0; i < bpe->bpe_count; i++) { /* * If the block has DEDUP bit set, it means that it * already exists in the DEDUP table, so we can just * use that instead of creating new entry in * the BRT table. */ if (BP_GET_DEDUP(&bpe->bpe_bp)) { added_to_ddt = ddt_addref(spa, &bpe->bpe_bp); } else { added_to_ddt = B_FALSE; } if (!added_to_ddt) brt_entry_addref(brt, &bpe->bpe_bp); } kmem_cache_free(brt_pending_entry_cache, bpe); mutex_enter(pending_lock); } mutex_exit(pending_lock); } static void brt_sync_entry(brt_t *brt, brt_vdev_t *brtvd, brt_entry_t *bre, dmu_tx_t *tx) { ASSERT(RW_WRITE_HELD(&brt->brt_lock)); ASSERT(brtvd->bv_mos_entries != 0); if (bre->bre_refcount == 0) { int error; error = brt_entry_remove(brt, brtvd, bre, tx); ASSERT(error == 0 || error == ENOENT); /* * If error == ENOENT then zfs_clone_range() was done from a * removed (but opened) file (open(), unlink()). */ ASSERT(brt_entry_lookup(brt, brtvd, bre) == ENOENT); } else { VERIFY0(brt_entry_update(brt, brtvd, bre, tx)); } } static void brt_sync_table(brt_t *brt, dmu_tx_t *tx) { brt_vdev_t *brtvd; brt_entry_t *bre; uint64_t vdevid; void *c; brt_wlock(brt); for (vdevid = 0; vdevid < brt->brt_nvdevs; vdevid++) { brtvd = &brt->brt_vdevs[vdevid]; if (!brtvd->bv_initiated) continue; if (!brtvd->bv_meta_dirty) { ASSERT(!brtvd->bv_entcount_dirty); ASSERT0(avl_numnodes(&brtvd->bv_tree)); continue; } ASSERT(!brtvd->bv_entcount_dirty || avl_numnodes(&brtvd->bv_tree) != 0); if (brtvd->bv_mos_brtvdev == 0) brt_vdev_create(brt, brtvd, tx); c = NULL; while ((bre = avl_destroy_nodes(&brtvd->bv_tree, &c)) != NULL) { brt_sync_entry(brt, brtvd, bre, tx); brt_entry_free(bre); ASSERT(brt->brt_nentries > 0); brt->brt_nentries--; } brt_vdev_sync(brt, brtvd, tx); if (brtvd->bv_totalcount == 0) brt_vdev_destroy(brt, brtvd, tx); } ASSERT0(brt->brt_nentries); brt_unlock(brt); } void brt_sync(spa_t *spa, uint64_t txg) { dmu_tx_t *tx; brt_t *brt; ASSERT(spa_syncing_txg(spa) == txg); brt = spa->spa_brt; brt_rlock(brt); if (brt->brt_nentries == 0) { /* No changes. */ brt_unlock(brt); return; } brt_unlock(brt); tx = dmu_tx_create_assigned(spa->spa_dsl_pool, txg); brt_sync_table(brt, tx); dmu_tx_commit(tx); } static void brt_table_alloc(brt_t *brt) { for (int i = 0; i < TXG_SIZE; i++) { avl_create(&brt->brt_pending_tree[i], brt_pending_entry_compare, sizeof (brt_pending_entry_t), offsetof(brt_pending_entry_t, bpe_node)); mutex_init(&brt->brt_pending_lock[i], NULL, MUTEX_DEFAULT, NULL); } } static void brt_table_free(brt_t *brt) { for (int i = 0; i < TXG_SIZE; i++) { ASSERT(avl_is_empty(&brt->brt_pending_tree[i])); avl_destroy(&brt->brt_pending_tree[i]); mutex_destroy(&brt->brt_pending_lock[i]); } } static void brt_alloc(spa_t *spa) { brt_t *brt; ASSERT(spa->spa_brt == NULL); brt = kmem_zalloc(sizeof (*brt), KM_SLEEP); rw_init(&brt->brt_lock, NULL, RW_DEFAULT, NULL); brt->brt_spa = spa; brt->brt_rangesize = 0; brt->brt_nentries = 0; brt->brt_vdevs = NULL; brt->brt_nvdevs = 0; brt_table_alloc(brt); spa->spa_brt = brt; } void brt_create(spa_t *spa) { brt_alloc(spa); brt_vdevs_alloc(spa->spa_brt, B_FALSE); } int brt_load(spa_t *spa) { brt_alloc(spa); brt_vdevs_alloc(spa->spa_brt, B_TRUE); return (0); } void brt_unload(spa_t *spa) { brt_t *brt = spa->spa_brt; if (brt == NULL) return; brt_vdevs_free(brt); brt_table_free(brt); rw_destroy(&brt->brt_lock); kmem_free(brt, sizeof (*brt)); spa->spa_brt = NULL; } /* BEGIN CSTYLED */ ZFS_MODULE_PARAM(zfs_brt, zfs_brt_, prefetch, INT, ZMOD_RW, "Enable prefetching of BRT entries"); #ifdef ZFS_BRT_DEBUG ZFS_MODULE_PARAM(zfs_brt, zfs_brt_, debug, INT, ZMOD_RW, "BRT debug"); #endif /* END CSTYLED */