diff options
Diffstat (limited to 'module/zfs/dnode.c')
| -rw-r--r-- | module/zfs/dnode.c | 1443 |
1 files changed, 1443 insertions, 0 deletions
diff --git a/module/zfs/dnode.c b/module/zfs/dnode.c new file mode 100644 index 000000000..e77834d60 --- /dev/null +++ b/module/zfs/dnode.c @@ -0,0 +1,1443 @@ +/* + * 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 2008 Sun Microsystems, Inc. All rights reserved. + * Use is subject to license terms. + */ + +#include <sys/zfs_context.h> +#include <sys/dbuf.h> +#include <sys/dnode.h> +#include <sys/dmu.h> +#include <sys/dmu_impl.h> +#include <sys/dmu_tx.h> +#include <sys/dmu_objset.h> +#include <sys/dsl_dir.h> +#include <sys/dsl_dataset.h> +#include <sys/spa.h> +#include <sys/zio.h> +#include <sys/dmu_zfetch.h> + +static int free_range_compar(const void *node1, const void *node2); + +static kmem_cache_t *dnode_cache; + +static dnode_phys_t dnode_phys_zero; + +int zfs_default_bs = SPA_MINBLOCKSHIFT; +int zfs_default_ibs = DN_MAX_INDBLKSHIFT; + +/* ARGSUSED */ +static int +dnode_cons(void *arg, void *unused, int kmflag) +{ + int i; + dnode_t *dn = arg; + bzero(dn, sizeof (dnode_t)); + + rw_init(&dn->dn_struct_rwlock, NULL, RW_DEFAULT, NULL); + mutex_init(&dn->dn_mtx, NULL, MUTEX_DEFAULT, NULL); + mutex_init(&dn->dn_dbufs_mtx, NULL, MUTEX_DEFAULT, NULL); + refcount_create(&dn->dn_holds); + refcount_create(&dn->dn_tx_holds); + + for (i = 0; i < TXG_SIZE; i++) { + avl_create(&dn->dn_ranges[i], free_range_compar, + sizeof (free_range_t), + offsetof(struct free_range, fr_node)); + list_create(&dn->dn_dirty_records[i], + sizeof (dbuf_dirty_record_t), + offsetof(dbuf_dirty_record_t, dr_dirty_node)); + } + + list_create(&dn->dn_dbufs, sizeof (dmu_buf_impl_t), + offsetof(dmu_buf_impl_t, db_link)); + + return (0); +} + +/* ARGSUSED */ +static void +dnode_dest(void *arg, void *unused) +{ + int i; + dnode_t *dn = arg; + + rw_destroy(&dn->dn_struct_rwlock); + mutex_destroy(&dn->dn_mtx); + mutex_destroy(&dn->dn_dbufs_mtx); + refcount_destroy(&dn->dn_holds); + refcount_destroy(&dn->dn_tx_holds); + + for (i = 0; i < TXG_SIZE; i++) { + avl_destroy(&dn->dn_ranges[i]); + list_destroy(&dn->dn_dirty_records[i]); + } + + list_destroy(&dn->dn_dbufs); +} + +void +dnode_init(void) +{ + dnode_cache = kmem_cache_create("dnode_t", + sizeof (dnode_t), + 0, dnode_cons, dnode_dest, NULL, NULL, NULL, 0); +} + +void +dnode_fini(void) +{ + kmem_cache_destroy(dnode_cache); +} + + +#ifdef ZFS_DEBUG +void +dnode_verify(dnode_t *dn) +{ + int drop_struct_lock = FALSE; + + ASSERT(dn->dn_phys); + ASSERT(dn->dn_objset); + + ASSERT(dn->dn_phys->dn_type < DMU_OT_NUMTYPES); + + if (!(zfs_flags & ZFS_DEBUG_DNODE_VERIFY)) + return; + + if (!RW_WRITE_HELD(&dn->dn_struct_rwlock)) { + rw_enter(&dn->dn_struct_rwlock, RW_READER); + drop_struct_lock = TRUE; + } + if (dn->dn_phys->dn_type != DMU_OT_NONE || dn->dn_allocated_txg != 0) { + int i; + ASSERT3U(dn->dn_indblkshift, >=, 0); + ASSERT3U(dn->dn_indblkshift, <=, SPA_MAXBLOCKSHIFT); + if (dn->dn_datablkshift) { + ASSERT3U(dn->dn_datablkshift, >=, SPA_MINBLOCKSHIFT); + ASSERT3U(dn->dn_datablkshift, <=, SPA_MAXBLOCKSHIFT); + ASSERT3U(1<<dn->dn_datablkshift, ==, dn->dn_datablksz); + } + ASSERT3U(dn->dn_nlevels, <=, 30); + ASSERT3U(dn->dn_type, <=, DMU_OT_NUMTYPES); + ASSERT3U(dn->dn_nblkptr, >=, 1); + ASSERT3U(dn->dn_nblkptr, <=, DN_MAX_NBLKPTR); + ASSERT3U(dn->dn_bonuslen, <=, DN_MAX_BONUSLEN); + ASSERT3U(dn->dn_datablksz, ==, + dn->dn_datablkszsec << SPA_MINBLOCKSHIFT); + ASSERT3U(ISP2(dn->dn_datablksz), ==, dn->dn_datablkshift != 0); + ASSERT3U((dn->dn_nblkptr - 1) * sizeof (blkptr_t) + + dn->dn_bonuslen, <=, DN_MAX_BONUSLEN); + for (i = 0; i < TXG_SIZE; i++) { + ASSERT3U(dn->dn_next_nlevels[i], <=, dn->dn_nlevels); + } + } + if (dn->dn_phys->dn_type != DMU_OT_NONE) + ASSERT3U(dn->dn_phys->dn_nlevels, <=, dn->dn_nlevels); + ASSERT(dn->dn_object == DMU_META_DNODE_OBJECT || dn->dn_dbuf != NULL); + if (dn->dn_dbuf != NULL) { + ASSERT3P(dn->dn_phys, ==, + (dnode_phys_t *)dn->dn_dbuf->db.db_data + + (dn->dn_object % (dn->dn_dbuf->db.db_size >> DNODE_SHIFT))); + } + if (drop_struct_lock) + rw_exit(&dn->dn_struct_rwlock); +} +#endif + +void +dnode_byteswap(dnode_phys_t *dnp) +{ + uint64_t *buf64 = (void*)&dnp->dn_blkptr; + int i; + + if (dnp->dn_type == DMU_OT_NONE) { + bzero(dnp, sizeof (dnode_phys_t)); + return; + } + + dnp->dn_datablkszsec = BSWAP_16(dnp->dn_datablkszsec); + dnp->dn_bonuslen = BSWAP_16(dnp->dn_bonuslen); + dnp->dn_maxblkid = BSWAP_64(dnp->dn_maxblkid); + dnp->dn_used = BSWAP_64(dnp->dn_used); + + /* + * dn_nblkptr is only one byte, so it's OK to read it in either + * byte order. We can't read dn_bouslen. + */ + ASSERT(dnp->dn_indblkshift <= SPA_MAXBLOCKSHIFT); + ASSERT(dnp->dn_nblkptr <= DN_MAX_NBLKPTR); + for (i = 0; i < dnp->dn_nblkptr * sizeof (blkptr_t)/8; i++) + buf64[i] = BSWAP_64(buf64[i]); + + /* + * OK to check dn_bonuslen for zero, because it won't matter if + * we have the wrong byte order. This is necessary because the + * dnode dnode is smaller than a regular dnode. + */ + if (dnp->dn_bonuslen != 0) { + /* + * Note that the bonus length calculated here may be + * longer than the actual bonus buffer. This is because + * we always put the bonus buffer after the last block + * pointer (instead of packing it against the end of the + * dnode buffer). + */ + int off = (dnp->dn_nblkptr-1) * sizeof (blkptr_t); + size_t len = DN_MAX_BONUSLEN - off; + ASSERT3U(dnp->dn_bonustype, <, DMU_OT_NUMTYPES); + dmu_ot[dnp->dn_bonustype].ot_byteswap(dnp->dn_bonus + off, len); + } +} + +void +dnode_buf_byteswap(void *vbuf, size_t size) +{ + dnode_phys_t *buf = vbuf; + int i; + + ASSERT3U(sizeof (dnode_phys_t), ==, (1<<DNODE_SHIFT)); + ASSERT((size & (sizeof (dnode_phys_t)-1)) == 0); + + size >>= DNODE_SHIFT; + for (i = 0; i < size; i++) { + dnode_byteswap(buf); + buf++; + } +} + +static int +free_range_compar(const void *node1, const void *node2) +{ + const free_range_t *rp1 = node1; + const free_range_t *rp2 = node2; + + if (rp1->fr_blkid < rp2->fr_blkid) + return (-1); + else if (rp1->fr_blkid > rp2->fr_blkid) + return (1); + else return (0); +} + +void +dnode_setbonuslen(dnode_t *dn, int newsize, dmu_tx_t *tx) +{ + ASSERT3U(refcount_count(&dn->dn_holds), >=, 1); + + dnode_setdirty(dn, tx); + rw_enter(&dn->dn_struct_rwlock, RW_WRITER); + ASSERT3U(newsize, <=, DN_MAX_BONUSLEN - + (dn->dn_nblkptr-1) * sizeof (blkptr_t)); + dn->dn_bonuslen = newsize; + if (newsize == 0) + dn->dn_next_bonuslen[tx->tx_txg & TXG_MASK] = DN_ZERO_BONUSLEN; + else + dn->dn_next_bonuslen[tx->tx_txg & TXG_MASK] = dn->dn_bonuslen; + rw_exit(&dn->dn_struct_rwlock); +} + +static void +dnode_setdblksz(dnode_t *dn, int size) +{ + ASSERT3U(P2PHASE(size, SPA_MINBLOCKSIZE), ==, 0); + ASSERT3U(size, <=, SPA_MAXBLOCKSIZE); + ASSERT3U(size, >=, SPA_MINBLOCKSIZE); + ASSERT3U(size >> SPA_MINBLOCKSHIFT, <, + 1<<(sizeof (dn->dn_phys->dn_datablkszsec) * 8)); + dn->dn_datablksz = size; + dn->dn_datablkszsec = size >> SPA_MINBLOCKSHIFT; + dn->dn_datablkshift = ISP2(size) ? highbit(size - 1) : 0; +} + +static dnode_t * +dnode_create(objset_impl_t *os, dnode_phys_t *dnp, dmu_buf_impl_t *db, + uint64_t object) +{ + dnode_t *dn = kmem_cache_alloc(dnode_cache, KM_SLEEP); + (void) dnode_cons(dn, NULL, 0); /* XXX */ + + dn->dn_objset = os; + dn->dn_object = object; + dn->dn_dbuf = db; + dn->dn_phys = dnp; + + if (dnp->dn_datablkszsec) + dnode_setdblksz(dn, dnp->dn_datablkszsec << SPA_MINBLOCKSHIFT); + dn->dn_indblkshift = dnp->dn_indblkshift; + dn->dn_nlevels = dnp->dn_nlevels; + dn->dn_type = dnp->dn_type; + dn->dn_nblkptr = dnp->dn_nblkptr; + dn->dn_checksum = dnp->dn_checksum; + dn->dn_compress = dnp->dn_compress; + dn->dn_bonustype = dnp->dn_bonustype; + dn->dn_bonuslen = dnp->dn_bonuslen; + dn->dn_maxblkid = dnp->dn_maxblkid; + + dmu_zfetch_init(&dn->dn_zfetch, dn); + + ASSERT(dn->dn_phys->dn_type < DMU_OT_NUMTYPES); + mutex_enter(&os->os_lock); + list_insert_head(&os->os_dnodes, dn); + mutex_exit(&os->os_lock); + + arc_space_consume(sizeof (dnode_t)); + return (dn); +} + +static void +dnode_destroy(dnode_t *dn) +{ + objset_impl_t *os = dn->dn_objset; + +#ifdef ZFS_DEBUG + int i; + + for (i = 0; i < TXG_SIZE; i++) { + ASSERT(!list_link_active(&dn->dn_dirty_link[i])); + ASSERT(NULL == list_head(&dn->dn_dirty_records[i])); + ASSERT(0 == avl_numnodes(&dn->dn_ranges[i])); + } + ASSERT(NULL == list_head(&dn->dn_dbufs)); +#endif + + mutex_enter(&os->os_lock); + list_remove(&os->os_dnodes, dn); + mutex_exit(&os->os_lock); + + if (dn->dn_dirtyctx_firstset) { + kmem_free(dn->dn_dirtyctx_firstset, 1); + dn->dn_dirtyctx_firstset = NULL; + } + dmu_zfetch_rele(&dn->dn_zfetch); + if (dn->dn_bonus) { + mutex_enter(&dn->dn_bonus->db_mtx); + dbuf_evict(dn->dn_bonus); + dn->dn_bonus = NULL; + } + kmem_cache_free(dnode_cache, dn); + arc_space_return(sizeof (dnode_t)); +} + +void +dnode_allocate(dnode_t *dn, dmu_object_type_t ot, int blocksize, int ibs, + dmu_object_type_t bonustype, int bonuslen, dmu_tx_t *tx) +{ + int i; + + if (blocksize == 0) + blocksize = 1 << zfs_default_bs; + else if (blocksize > SPA_MAXBLOCKSIZE) + blocksize = SPA_MAXBLOCKSIZE; + else + blocksize = P2ROUNDUP(blocksize, SPA_MINBLOCKSIZE); + + if (ibs == 0) + ibs = zfs_default_ibs; + + ibs = MIN(MAX(ibs, DN_MIN_INDBLKSHIFT), DN_MAX_INDBLKSHIFT); + + dprintf("os=%p obj=%llu txg=%llu blocksize=%d ibs=%d\n", dn->dn_objset, + dn->dn_object, tx->tx_txg, blocksize, ibs); + + ASSERT(dn->dn_type == DMU_OT_NONE); + ASSERT(bcmp(dn->dn_phys, &dnode_phys_zero, sizeof (dnode_phys_t)) == 0); + ASSERT(dn->dn_phys->dn_type == DMU_OT_NONE); + ASSERT(ot != DMU_OT_NONE); + ASSERT3U(ot, <, DMU_OT_NUMTYPES); + ASSERT((bonustype == DMU_OT_NONE && bonuslen == 0) || + (bonustype != DMU_OT_NONE && bonuslen != 0)); + ASSERT3U(bonustype, <, DMU_OT_NUMTYPES); + ASSERT3U(bonuslen, <=, DN_MAX_BONUSLEN); + ASSERT(dn->dn_type == DMU_OT_NONE); + ASSERT3U(dn->dn_maxblkid, ==, 0); + ASSERT3U(dn->dn_allocated_txg, ==, 0); + ASSERT3U(dn->dn_assigned_txg, ==, 0); + ASSERT(refcount_is_zero(&dn->dn_tx_holds)); + ASSERT3U(refcount_count(&dn->dn_holds), <=, 1); + ASSERT3P(list_head(&dn->dn_dbufs), ==, NULL); + + for (i = 0; i < TXG_SIZE; i++) { + ASSERT3U(dn->dn_next_nlevels[i], ==, 0); + ASSERT3U(dn->dn_next_indblkshift[i], ==, 0); + ASSERT3U(dn->dn_next_bonuslen[i], ==, 0); + ASSERT3U(dn->dn_next_blksz[i], ==, 0); + ASSERT(!list_link_active(&dn->dn_dirty_link[i])); + ASSERT3P(list_head(&dn->dn_dirty_records[i]), ==, NULL); + ASSERT3U(avl_numnodes(&dn->dn_ranges[i]), ==, 0); + } + + dn->dn_type = ot; + dnode_setdblksz(dn, blocksize); + dn->dn_indblkshift = ibs; + dn->dn_nlevels = 1; + dn->dn_nblkptr = 1 + ((DN_MAX_BONUSLEN - bonuslen) >> SPA_BLKPTRSHIFT); + dn->dn_bonustype = bonustype; + dn->dn_bonuslen = bonuslen; + dn->dn_checksum = ZIO_CHECKSUM_INHERIT; + dn->dn_compress = ZIO_COMPRESS_INHERIT; + dn->dn_dirtyctx = 0; + + dn->dn_free_txg = 0; + if (dn->dn_dirtyctx_firstset) { + kmem_free(dn->dn_dirtyctx_firstset, 1); + dn->dn_dirtyctx_firstset = NULL; + } + + dn->dn_allocated_txg = tx->tx_txg; + + dnode_setdirty(dn, tx); + dn->dn_next_indblkshift[tx->tx_txg & TXG_MASK] = ibs; + dn->dn_next_bonuslen[tx->tx_txg & TXG_MASK] = dn->dn_bonuslen; + dn->dn_next_blksz[tx->tx_txg & TXG_MASK] = dn->dn_datablksz; +} + +void +dnode_reallocate(dnode_t *dn, dmu_object_type_t ot, int blocksize, + dmu_object_type_t bonustype, int bonuslen, dmu_tx_t *tx) +{ + int i, old_nblkptr; + dmu_buf_impl_t *db = NULL; + + ASSERT3U(blocksize, >=, SPA_MINBLOCKSIZE); + ASSERT3U(blocksize, <=, SPA_MAXBLOCKSIZE); + ASSERT3U(blocksize % SPA_MINBLOCKSIZE, ==, 0); + ASSERT(dn->dn_object != DMU_META_DNODE_OBJECT || dmu_tx_private_ok(tx)); + ASSERT(tx->tx_txg != 0); + ASSERT((bonustype == DMU_OT_NONE && bonuslen == 0) || + (bonustype != DMU_OT_NONE && bonuslen != 0)); + ASSERT3U(bonustype, <, DMU_OT_NUMTYPES); + ASSERT3U(bonuslen, <=, DN_MAX_BONUSLEN); + + for (i = 0; i < TXG_SIZE; i++) + ASSERT(!list_link_active(&dn->dn_dirty_link[i])); + + /* clean up any unreferenced dbufs */ + dnode_evict_dbufs(dn); + ASSERT3P(list_head(&dn->dn_dbufs), ==, NULL); + + /* + * XXX I should really have a generation number to tell if we + * need to do this... + */ + if (blocksize != dn->dn_datablksz || + dn->dn_bonustype != bonustype || dn->dn_bonuslen != bonuslen) { + /* free all old data */ + dnode_free_range(dn, 0, -1ULL, tx); + } + + /* change blocksize */ + rw_enter(&dn->dn_struct_rwlock, RW_WRITER); + if (blocksize != dn->dn_datablksz && + (!BP_IS_HOLE(&dn->dn_phys->dn_blkptr[0]) || + list_head(&dn->dn_dbufs) != NULL)) { + db = dbuf_hold(dn, 0, FTAG); + dbuf_new_size(db, blocksize, tx); + } + dnode_setdblksz(dn, blocksize); + dnode_setdirty(dn, tx); + dn->dn_next_bonuslen[tx->tx_txg&TXG_MASK] = bonuslen; + dn->dn_next_blksz[tx->tx_txg&TXG_MASK] = blocksize; + rw_exit(&dn->dn_struct_rwlock); + if (db) + dbuf_rele(db, FTAG); + + /* change type */ + dn->dn_type = ot; + + /* change bonus size and type */ + mutex_enter(&dn->dn_mtx); + old_nblkptr = dn->dn_nblkptr; + dn->dn_bonustype = bonustype; + dn->dn_bonuslen = bonuslen; + dn->dn_nblkptr = 1 + ((DN_MAX_BONUSLEN - bonuslen) >> SPA_BLKPTRSHIFT); + dn->dn_checksum = ZIO_CHECKSUM_INHERIT; + dn->dn_compress = ZIO_COMPRESS_INHERIT; + ASSERT3U(dn->dn_nblkptr, <=, DN_MAX_NBLKPTR); + + /* XXX - for now, we can't make nblkptr smaller */ + ASSERT3U(dn->dn_nblkptr, >=, old_nblkptr); + + /* fix up the bonus db_size if dn_nblkptr has changed */ + if (dn->dn_bonus && dn->dn_bonuslen != old_nblkptr) { + dn->dn_bonus->db.db_size = + DN_MAX_BONUSLEN - (dn->dn_nblkptr-1) * sizeof (blkptr_t); + ASSERT(dn->dn_bonuslen <= dn->dn_bonus->db.db_size); + } + + dn->dn_allocated_txg = tx->tx_txg; + mutex_exit(&dn->dn_mtx); +} + +void +dnode_special_close(dnode_t *dn) +{ + /* + * Wait for final references to the dnode to clear. This can + * only happen if the arc is asyncronously evicting state that + * has a hold on this dnode while we are trying to evict this + * dnode. + */ + while (refcount_count(&dn->dn_holds) > 0) + delay(1); + dnode_destroy(dn); +} + +dnode_t * +dnode_special_open(objset_impl_t *os, dnode_phys_t *dnp, uint64_t object) +{ + dnode_t *dn = dnode_create(os, dnp, NULL, object); + DNODE_VERIFY(dn); + return (dn); +} + +static void +dnode_buf_pageout(dmu_buf_t *db, void *arg) +{ + dnode_t **children_dnodes = arg; + int i; + int epb = db->db_size >> DNODE_SHIFT; + + for (i = 0; i < epb; i++) { + dnode_t *dn = children_dnodes[i]; + int n; + + if (dn == NULL) + continue; +#ifdef ZFS_DEBUG + /* + * If there are holds on this dnode, then there should + * be holds on the dnode's containing dbuf as well; thus + * it wouldn't be eligable for eviction and this function + * would not have been called. + */ + ASSERT(refcount_is_zero(&dn->dn_holds)); + ASSERT(list_head(&dn->dn_dbufs) == NULL); + ASSERT(refcount_is_zero(&dn->dn_tx_holds)); + + for (n = 0; n < TXG_SIZE; n++) + ASSERT(!list_link_active(&dn->dn_dirty_link[n])); +#endif + children_dnodes[i] = NULL; + dnode_destroy(dn); + } + kmem_free(children_dnodes, epb * sizeof (dnode_t *)); +} + +/* + * errors: + * EINVAL - invalid object number. + * EIO - i/o error. + * succeeds even for free dnodes. + */ +int +dnode_hold_impl(objset_impl_t *os, uint64_t object, int flag, + void *tag, dnode_t **dnp) +{ + int epb, idx, err; + int drop_struct_lock = FALSE; + int type; + uint64_t blk; + dnode_t *mdn, *dn; + dmu_buf_impl_t *db; + dnode_t **children_dnodes; + + /* + * If you are holding the spa config lock as writer, you shouldn't + * be asking the DMU to do *anything*. + */ + ASSERT(spa_config_held(os->os_spa, SCL_ALL, RW_WRITER) == 0); + + if (object == 0 || object >= DN_MAX_OBJECT) + return (EINVAL); + + mdn = os->os_meta_dnode; + + DNODE_VERIFY(mdn); + + if (!RW_WRITE_HELD(&mdn->dn_struct_rwlock)) { + rw_enter(&mdn->dn_struct_rwlock, RW_READER); + drop_struct_lock = TRUE; + } + + blk = dbuf_whichblock(mdn, object * sizeof (dnode_phys_t)); + + db = dbuf_hold(mdn, blk, FTAG); + if (drop_struct_lock) + rw_exit(&mdn->dn_struct_rwlock); + if (db == NULL) + return (EIO); + err = dbuf_read(db, NULL, DB_RF_CANFAIL); + if (err) { + dbuf_rele(db, FTAG); + return (err); + } + + ASSERT3U(db->db.db_size, >=, 1<<DNODE_SHIFT); + epb = db->db.db_size >> DNODE_SHIFT; + + idx = object & (epb-1); + + children_dnodes = dmu_buf_get_user(&db->db); + if (children_dnodes == NULL) { + dnode_t **winner; + children_dnodes = kmem_zalloc(epb * sizeof (dnode_t *), + KM_SLEEP); + if (winner = dmu_buf_set_user(&db->db, children_dnodes, NULL, + dnode_buf_pageout)) { + kmem_free(children_dnodes, epb * sizeof (dnode_t *)); + children_dnodes = winner; + } + } + + if ((dn = children_dnodes[idx]) == NULL) { + dnode_phys_t *dnp = (dnode_phys_t *)db->db.db_data+idx; + dnode_t *winner; + + dn = dnode_create(os, dnp, db, object); + winner = atomic_cas_ptr(&children_dnodes[idx], NULL, dn); + if (winner != NULL) { + dnode_destroy(dn); + dn = winner; + } + } + + mutex_enter(&dn->dn_mtx); + type = dn->dn_type; + if (dn->dn_free_txg || + ((flag & DNODE_MUST_BE_ALLOCATED) && type == DMU_OT_NONE) || + ((flag & DNODE_MUST_BE_FREE) && type != DMU_OT_NONE)) { + mutex_exit(&dn->dn_mtx); + dbuf_rele(db, FTAG); + return (type == DMU_OT_NONE ? ENOENT : EEXIST); + } + mutex_exit(&dn->dn_mtx); + + if (refcount_add(&dn->dn_holds, tag) == 1) + dbuf_add_ref(db, dn); + + DNODE_VERIFY(dn); + ASSERT3P(dn->dn_dbuf, ==, db); + ASSERT3U(dn->dn_object, ==, object); + dbuf_rele(db, FTAG); + + *dnp = dn; + return (0); +} + +/* + * Return held dnode if the object is allocated, NULL if not. + */ +int +dnode_hold(objset_impl_t *os, uint64_t object, void *tag, dnode_t **dnp) +{ + return (dnode_hold_impl(os, object, DNODE_MUST_BE_ALLOCATED, tag, dnp)); +} + +/* + * Can only add a reference if there is already at least one + * reference on the dnode. Returns FALSE if unable to add a + * new reference. + */ +boolean_t +dnode_add_ref(dnode_t *dn, void *tag) +{ + mutex_enter(&dn->dn_mtx); + if (refcount_is_zero(&dn->dn_holds)) { + mutex_exit(&dn->dn_mtx); + return (FALSE); + } + VERIFY(1 < refcount_add(&dn->dn_holds, tag)); + mutex_exit(&dn->dn_mtx); + return (TRUE); +} + +void +dnode_rele(dnode_t *dn, void *tag) +{ + uint64_t refs; + + mutex_enter(&dn->dn_mtx); + refs = refcount_remove(&dn->dn_holds, tag); + mutex_exit(&dn->dn_mtx); + /* NOTE: the DNODE_DNODE does not have a dn_dbuf */ + if (refs == 0 && dn->dn_dbuf) + dbuf_rele(dn->dn_dbuf, dn); +} + +void +dnode_setdirty(dnode_t *dn, dmu_tx_t *tx) +{ + objset_impl_t *os = dn->dn_objset; + uint64_t txg = tx->tx_txg; + + if (dn->dn_object == DMU_META_DNODE_OBJECT) + return; + + DNODE_VERIFY(dn); + +#ifdef ZFS_DEBUG + mutex_enter(&dn->dn_mtx); + ASSERT(dn->dn_phys->dn_type || dn->dn_allocated_txg); + /* ASSERT(dn->dn_free_txg == 0 || dn->dn_free_txg >= txg); */ + mutex_exit(&dn->dn_mtx); +#endif + + mutex_enter(&os->os_lock); + + /* + * If we are already marked dirty, we're done. + */ + if (list_link_active(&dn->dn_dirty_link[txg & TXG_MASK])) { + mutex_exit(&os->os_lock); + return; + } + + ASSERT(!refcount_is_zero(&dn->dn_holds) || list_head(&dn->dn_dbufs)); + ASSERT(dn->dn_datablksz != 0); + ASSERT3U(dn->dn_next_bonuslen[txg&TXG_MASK], ==, 0); + ASSERT3U(dn->dn_next_blksz[txg&TXG_MASK], ==, 0); + + dprintf_ds(os->os_dsl_dataset, "obj=%llu txg=%llu\n", + dn->dn_object, txg); + + if (dn->dn_free_txg > 0 && dn->dn_free_txg <= txg) { + list_insert_tail(&os->os_free_dnodes[txg&TXG_MASK], dn); + } else { + list_insert_tail(&os->os_dirty_dnodes[txg&TXG_MASK], dn); + } + + mutex_exit(&os->os_lock); + + /* + * The dnode maintains a hold on its containing dbuf as + * long as there are holds on it. Each instantiated child + * dbuf maintaines a hold on the dnode. When the last child + * drops its hold, the dnode will drop its hold on the + * containing dbuf. We add a "dirty hold" here so that the + * dnode will hang around after we finish processing its + * children. + */ + VERIFY(dnode_add_ref(dn, (void *)(uintptr_t)tx->tx_txg)); + + (void) dbuf_dirty(dn->dn_dbuf, tx); + + dsl_dataset_dirty(os->os_dsl_dataset, tx); +} + +void +dnode_free(dnode_t *dn, dmu_tx_t *tx) +{ + int txgoff = tx->tx_txg & TXG_MASK; + + dprintf("dn=%p txg=%llu\n", dn, tx->tx_txg); + + /* we should be the only holder... hopefully */ + /* ASSERT3U(refcount_count(&dn->dn_holds), ==, 1); */ + + mutex_enter(&dn->dn_mtx); + if (dn->dn_type == DMU_OT_NONE || dn->dn_free_txg) { + mutex_exit(&dn->dn_mtx); + return; + } + dn->dn_free_txg = tx->tx_txg; + mutex_exit(&dn->dn_mtx); + + /* + * If the dnode is already dirty, it needs to be moved from + * the dirty list to the free list. + */ + mutex_enter(&dn->dn_objset->os_lock); + if (list_link_active(&dn->dn_dirty_link[txgoff])) { + list_remove(&dn->dn_objset->os_dirty_dnodes[txgoff], dn); + list_insert_tail(&dn->dn_objset->os_free_dnodes[txgoff], dn); + mutex_exit(&dn->dn_objset->os_lock); + } else { + mutex_exit(&dn->dn_objset->os_lock); + dnode_setdirty(dn, tx); + } +} + +/* + * Try to change the block size for the indicated dnode. This can only + * succeed if there are no blocks allocated or dirty beyond first block + */ +int +dnode_set_blksz(dnode_t *dn, uint64_t size, int ibs, dmu_tx_t *tx) +{ + dmu_buf_impl_t *db, *db_next; + int err; + + if (size == 0) + size = SPA_MINBLOCKSIZE; + if (size > SPA_MAXBLOCKSIZE) + size = SPA_MAXBLOCKSIZE; + else + size = P2ROUNDUP(size, SPA_MINBLOCKSIZE); + + if (ibs == dn->dn_indblkshift) + ibs = 0; + + if (size >> SPA_MINBLOCKSHIFT == dn->dn_datablkszsec && ibs == 0) + return (0); + + rw_enter(&dn->dn_struct_rwlock, RW_WRITER); + + /* Check for any allocated blocks beyond the first */ + if (dn->dn_phys->dn_maxblkid != 0) + goto fail; + + mutex_enter(&dn->dn_dbufs_mtx); + for (db = list_head(&dn->dn_dbufs); db; db = db_next) { + db_next = list_next(&dn->dn_dbufs, db); + + if (db->db_blkid != 0 && db->db_blkid != DB_BONUS_BLKID) { + mutex_exit(&dn->dn_dbufs_mtx); + goto fail; + } + } + mutex_exit(&dn->dn_dbufs_mtx); + + if (ibs && dn->dn_nlevels != 1) + goto fail; + + /* resize the old block */ + err = dbuf_hold_impl(dn, 0, 0, TRUE, FTAG, &db); + if (err == 0) + dbuf_new_size(db, size, tx); + else if (err != ENOENT) + goto fail; + + dnode_setdblksz(dn, size); + dnode_setdirty(dn, tx); + dn->dn_next_blksz[tx->tx_txg&TXG_MASK] = size; + if (ibs) { + dn->dn_indblkshift = ibs; + dn->dn_next_indblkshift[tx->tx_txg&TXG_MASK] = ibs; + } + /* rele after we have fixed the blocksize in the dnode */ + if (db) + dbuf_rele(db, FTAG); + + rw_exit(&dn->dn_struct_rwlock); + return (0); + +fail: + rw_exit(&dn->dn_struct_rwlock); + return (ENOTSUP); +} + +/* read-holding callers must not rely on the lock being continuously held */ +void +dnode_new_blkid(dnode_t *dn, uint64_t blkid, dmu_tx_t *tx, boolean_t have_read) +{ + uint64_t txgoff = tx->tx_txg & TXG_MASK; + int epbs, new_nlevels; + uint64_t sz; + + ASSERT(blkid != DB_BONUS_BLKID); + + ASSERT(have_read ? + RW_READ_HELD(&dn->dn_struct_rwlock) : + RW_WRITE_HELD(&dn->dn_struct_rwlock)); + + /* + * if we have a read-lock, check to see if we need to do any work + * before upgrading to a write-lock. + */ + if (have_read) { + if (blkid <= dn->dn_maxblkid) + return; + + if (!rw_tryupgrade(&dn->dn_struct_rwlock)) { + rw_exit(&dn->dn_struct_rwlock); + rw_enter(&dn->dn_struct_rwlock, RW_WRITER); + } + } + + if (blkid <= dn->dn_maxblkid) + goto out; + + dn->dn_maxblkid = blkid; + + /* + * Compute the number of levels necessary to support the new maxblkid. + */ + new_nlevels = 1; + epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT; + for (sz = dn->dn_nblkptr; + sz <= blkid && sz >= dn->dn_nblkptr; sz <<= epbs) + new_nlevels++; + + if (new_nlevels > dn->dn_nlevels) { + int old_nlevels = dn->dn_nlevels; + dmu_buf_impl_t *db; + list_t *list; + dbuf_dirty_record_t *new, *dr, *dr_next; + + dn->dn_nlevels = new_nlevels; + + ASSERT3U(new_nlevels, >, dn->dn_next_nlevels[txgoff]); + dn->dn_next_nlevels[txgoff] = new_nlevels; + + /* dirty the left indirects */ + db = dbuf_hold_level(dn, old_nlevels, 0, FTAG); + new = dbuf_dirty(db, tx); + dbuf_rele(db, FTAG); + + /* transfer the dirty records to the new indirect */ + mutex_enter(&dn->dn_mtx); + mutex_enter(&new->dt.di.dr_mtx); + list = &dn->dn_dirty_records[txgoff]; + for (dr = list_head(list); dr; dr = dr_next) { + dr_next = list_next(&dn->dn_dirty_records[txgoff], dr); + if (dr->dr_dbuf->db_level != new_nlevels-1 && + dr->dr_dbuf->db_blkid != DB_BONUS_BLKID) { + ASSERT(dr->dr_dbuf->db_level == old_nlevels-1); + list_remove(&dn->dn_dirty_records[txgoff], dr); + list_insert_tail(&new->dt.di.dr_children, dr); + dr->dr_parent = new; + } + } + mutex_exit(&new->dt.di.dr_mtx); + mutex_exit(&dn->dn_mtx); + } + +out: + if (have_read) + rw_downgrade(&dn->dn_struct_rwlock); +} + +void +dnode_clear_range(dnode_t *dn, uint64_t blkid, uint64_t nblks, dmu_tx_t *tx) +{ + avl_tree_t *tree = &dn->dn_ranges[tx->tx_txg&TXG_MASK]; + avl_index_t where; + free_range_t *rp; + free_range_t rp_tofind; + uint64_t endblk = blkid + nblks; + + ASSERT(MUTEX_HELD(&dn->dn_mtx)); + ASSERT(nblks <= UINT64_MAX - blkid); /* no overflow */ + + dprintf_dnode(dn, "blkid=%llu nblks=%llu txg=%llu\n", + blkid, nblks, tx->tx_txg); + rp_tofind.fr_blkid = blkid; + rp = avl_find(tree, &rp_tofind, &where); + if (rp == NULL) + rp = avl_nearest(tree, where, AVL_BEFORE); + if (rp == NULL) + rp = avl_nearest(tree, where, AVL_AFTER); + + while (rp && (rp->fr_blkid <= blkid + nblks)) { + uint64_t fr_endblk = rp->fr_blkid + rp->fr_nblks; + free_range_t *nrp = AVL_NEXT(tree, rp); + + if (blkid <= rp->fr_blkid && endblk >= fr_endblk) { + /* clear this entire range */ + avl_remove(tree, rp); + kmem_free(rp, sizeof (free_range_t)); + } else if (blkid <= rp->fr_blkid && + endblk > rp->fr_blkid && endblk < fr_endblk) { + /* clear the beginning of this range */ + rp->fr_blkid = endblk; + rp->fr_nblks = fr_endblk - endblk; + } else if (blkid > rp->fr_blkid && blkid < fr_endblk && + endblk >= fr_endblk) { + /* clear the end of this range */ + rp->fr_nblks = blkid - rp->fr_blkid; + } else if (blkid > rp->fr_blkid && endblk < fr_endblk) { + /* clear a chunk out of this range */ + free_range_t *new_rp = + kmem_alloc(sizeof (free_range_t), KM_SLEEP); + + new_rp->fr_blkid = endblk; + new_rp->fr_nblks = fr_endblk - endblk; + avl_insert_here(tree, new_rp, rp, AVL_AFTER); + rp->fr_nblks = blkid - rp->fr_blkid; + } + /* there may be no overlap */ + rp = nrp; + } +} + +void +dnode_free_range(dnode_t *dn, uint64_t off, uint64_t len, dmu_tx_t *tx) +{ + dmu_buf_impl_t *db; + uint64_t blkoff, blkid, nblks; + int blksz, blkshift, head, tail; + int trunc = FALSE; + int epbs; + + rw_enter(&dn->dn_struct_rwlock, RW_WRITER); + blksz = dn->dn_datablksz; + blkshift = dn->dn_datablkshift; + epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT; + + if (len == -1ULL) { + len = UINT64_MAX - off; + trunc = TRUE; + } + + /* + * First, block align the region to free: + */ + if (ISP2(blksz)) { + head = P2NPHASE(off, blksz); + blkoff = P2PHASE(off, blksz); + if ((off >> blkshift) > dn->dn_maxblkid) + goto out; + } else { + ASSERT(dn->dn_maxblkid == 0); + if (off == 0 && len >= blksz) { + /* Freeing the whole block; fast-track this request */ + blkid = 0; + nblks = 1; + goto done; + } else if (off >= blksz) { + /* Freeing past end-of-data */ + goto out; + } else { + /* Freeing part of the block. */ + head = blksz - off; + ASSERT3U(head, >, 0); + } + blkoff = off; + } + /* zero out any partial block data at the start of the range */ + if (head) { + ASSERT3U(blkoff + head, ==, blksz); + if (len < head) + head = len; + if (dbuf_hold_impl(dn, 0, dbuf_whichblock(dn, off), TRUE, + FTAG, &db) == 0) { + caddr_t data; + + /* don't dirty if it isn't on disk and isn't dirty */ + if (db->db_last_dirty || + (db->db_blkptr && !BP_IS_HOLE(db->db_blkptr))) { + rw_exit(&dn->dn_struct_rwlock); + dbuf_will_dirty(db, tx); + rw_enter(&dn->dn_struct_rwlock, RW_WRITER); + data = db->db.db_data; + bzero(data + blkoff, head); + } + dbuf_rele(db, FTAG); + } + off += head; + len -= head; + } + + /* If the range was less than one block, we're done */ + if (len == 0) + goto out; + + /* If the remaining range is past end of file, we're done */ + if ((off >> blkshift) > dn->dn_maxblkid) + goto out; + + ASSERT(ISP2(blksz)); + if (trunc) + tail = 0; + else + tail = P2PHASE(len, blksz); + + ASSERT3U(P2PHASE(off, blksz), ==, 0); + /* zero out any partial block data at the end of the range */ + if (tail) { + if (len < tail) + tail = len; + if (dbuf_hold_impl(dn, 0, dbuf_whichblock(dn, off+len), + TRUE, FTAG, &db) == 0) { + /* don't dirty if not on disk and not dirty */ + if (db->db_last_dirty || + (db->db_blkptr && !BP_IS_HOLE(db->db_blkptr))) { + rw_exit(&dn->dn_struct_rwlock); + dbuf_will_dirty(db, tx); + rw_enter(&dn->dn_struct_rwlock, RW_WRITER); + bzero(db->db.db_data, tail); + } + dbuf_rele(db, FTAG); + } + len -= tail; + } + + /* If the range did not include a full block, we are done */ + if (len == 0) + goto out; + + ASSERT(IS_P2ALIGNED(off, blksz)); + ASSERT(trunc || IS_P2ALIGNED(len, blksz)); + blkid = off >> blkshift; + nblks = len >> blkshift; + if (trunc) + nblks += 1; + + /* + * Read in and mark all the level-1 indirects dirty, + * so that they will stay in memory until syncing phase. + * Always dirty the first and last indirect to make sure + * we dirty all the partial indirects. + */ + if (dn->dn_nlevels > 1) { + uint64_t i, first, last; + int shift = epbs + dn->dn_datablkshift; + + first = blkid >> epbs; + if (db = dbuf_hold_level(dn, 1, first, FTAG)) { + dbuf_will_dirty(db, tx); + dbuf_rele(db, FTAG); + } + if (trunc) + last = dn->dn_maxblkid >> epbs; + else + last = (blkid + nblks - 1) >> epbs; + if (last > first && (db = dbuf_hold_level(dn, 1, last, FTAG))) { + dbuf_will_dirty(db, tx); + dbuf_rele(db, FTAG); + } + for (i = first + 1; i < last; i++) { + uint64_t ibyte = i << shift; + int err; + + err = dnode_next_offset(dn, + DNODE_FIND_HAVELOCK, &ibyte, 1, 1, 0); + i = ibyte >> shift; + if (err == ESRCH || i >= last) + break; + ASSERT(err == 0); + db = dbuf_hold_level(dn, 1, i, FTAG); + if (db) { + dbuf_will_dirty(db, tx); + dbuf_rele(db, FTAG); + } + } + } +done: + /* + * Add this range to the dnode range list. + * We will finish up this free operation in the syncing phase. + */ + mutex_enter(&dn->dn_mtx); + dnode_clear_range(dn, blkid, nblks, tx); + { + free_range_t *rp, *found; + avl_index_t where; + avl_tree_t *tree = &dn->dn_ranges[tx->tx_txg&TXG_MASK]; + + /* Add new range to dn_ranges */ + rp = kmem_alloc(sizeof (free_range_t), KM_SLEEP); + rp->fr_blkid = blkid; + rp->fr_nblks = nblks; + found = avl_find(tree, rp, &where); + ASSERT(found == NULL); + avl_insert(tree, rp, where); + dprintf_dnode(dn, "blkid=%llu nblks=%llu txg=%llu\n", + blkid, nblks, tx->tx_txg); + } + mutex_exit(&dn->dn_mtx); + + dbuf_free_range(dn, blkid, blkid + nblks - 1, tx); + dnode_setdirty(dn, tx); +out: + if (trunc && dn->dn_maxblkid >= (off >> blkshift)) + dn->dn_maxblkid = (off >> blkshift ? (off >> blkshift) - 1 : 0); + + rw_exit(&dn->dn_struct_rwlock); +} + +/* return TRUE if this blkid was freed in a recent txg, or FALSE if it wasn't */ +uint64_t +dnode_block_freed(dnode_t *dn, uint64_t blkid) +{ + free_range_t range_tofind; + void *dp = spa_get_dsl(dn->dn_objset->os_spa); + int i; + + if (blkid == DB_BONUS_BLKID) + return (FALSE); + + /* + * If we're in the process of opening the pool, dp will not be + * set yet, but there shouldn't be anything dirty. + */ + if (dp == NULL) + return (FALSE); + + if (dn->dn_free_txg) + return (TRUE); + + /* + * If dn_datablkshift is not set, then there's only a single + * block, in which case there will never be a free range so it + * won't matter. + */ + range_tofind.fr_blkid = blkid; + mutex_enter(&dn->dn_mtx); + for (i = 0; i < TXG_SIZE; i++) { + free_range_t *range_found; + avl_index_t idx; + + range_found = avl_find(&dn->dn_ranges[i], &range_tofind, &idx); + if (range_found) { + ASSERT(range_found->fr_nblks > 0); + break; + } + range_found = avl_nearest(&dn->dn_ranges[i], idx, AVL_BEFORE); + if (range_found && + range_found->fr_blkid + range_found->fr_nblks > blkid) + break; + } + mutex_exit(&dn->dn_mtx); + return (i < TXG_SIZE); +} + +/* call from syncing context when we actually write/free space for this dnode */ +void +dnode_diduse_space(dnode_t *dn, int64_t delta) +{ + uint64_t space; + dprintf_dnode(dn, "dn=%p dnp=%p used=%llu delta=%lld\n", + dn, dn->dn_phys, + (u_longlong_t)dn->dn_phys->dn_used, + (longlong_t)delta); + + mutex_enter(&dn->dn_mtx); + space = DN_USED_BYTES(dn->dn_phys); + if (delta > 0) { + ASSERT3U(space + delta, >=, space); /* no overflow */ + } else { + ASSERT3U(space, >=, -delta); /* no underflow */ + } + space += delta; + if (spa_version(dn->dn_objset->os_spa) < SPA_VERSION_DNODE_BYTES) { + ASSERT((dn->dn_phys->dn_flags & DNODE_FLAG_USED_BYTES) == 0); + ASSERT3U(P2PHASE(space, 1<<DEV_BSHIFT), ==, 0); + dn->dn_phys->dn_used = space >> DEV_BSHIFT; + } else { + dn->dn_phys->dn_used = space; + dn->dn_phys->dn_flags |= DNODE_FLAG_USED_BYTES; + } + mutex_exit(&dn->dn_mtx); +} + +/* + * Call when we think we're going to write/free space in open context. + * Be conservative (ie. OK to write less than this or free more than + * this, but don't write more or free less). + */ +void +dnode_willuse_space(dnode_t *dn, int64_t space, dmu_tx_t *tx) +{ + objset_impl_t *os = dn->dn_objset; + dsl_dataset_t *ds = os->os_dsl_dataset; + + if (space > 0) + space = spa_get_asize(os->os_spa, space); + + if (ds) + dsl_dir_willuse_space(ds->ds_dir, space, tx); + + dmu_tx_willuse_space(tx, space); +} + +static int +dnode_next_offset_level(dnode_t *dn, int flags, uint64_t *offset, + int lvl, uint64_t blkfill, uint64_t txg) +{ + dmu_buf_impl_t *db = NULL; + void *data = NULL; + uint64_t epbs = dn->dn_phys->dn_indblkshift - SPA_BLKPTRSHIFT; + uint64_t epb = 1ULL << epbs; + uint64_t minfill, maxfill; + boolean_t hole; + int i, inc, error, span; + + dprintf("probing object %llu offset %llx level %d of %u\n", + dn->dn_object, *offset, lvl, dn->dn_phys->dn_nlevels); + + hole = flags & DNODE_FIND_HOLE; + inc = (flags & DNODE_FIND_BACKWARDS) ? -1 : 1; + ASSERT(txg == 0 || !hole); + + if (lvl == dn->dn_phys->dn_nlevels) { + error = 0; + epb = dn->dn_phys->dn_nblkptr; + data = dn->dn_phys->dn_blkptr; + } else { + uint64_t blkid = dbuf_whichblock(dn, *offset) >> (epbs * lvl); + error = dbuf_hold_impl(dn, lvl, blkid, TRUE, FTAG, &db); + if (error) { + if (error != ENOENT) + return (error); + if (hole) + return (0); + /* + * This can only happen when we are searching up + * the block tree for data. We don't really need to + * adjust the offset, as we will just end up looking + * at the pointer to this block in its parent, and its + * going to be unallocated, so we will skip over it. + */ + return (ESRCH); + } + error = dbuf_read(db, NULL, DB_RF_CANFAIL | DB_RF_HAVESTRUCT); + if (error) { + dbuf_rele(db, FTAG); + return (error); + } + data = db->db.db_data; + } + + if (db && txg && + (db->db_blkptr == NULL || db->db_blkptr->blk_birth <= txg)) { + /* + * This can only happen when we are searching up the tree + * and these conditions mean that we need to keep climbing. + */ + error = ESRCH; + } else if (lvl == 0) { + dnode_phys_t *dnp = data; + span = DNODE_SHIFT; + ASSERT(dn->dn_type == DMU_OT_DNODE); + + for (i = (*offset >> span) & (blkfill - 1); + i >= 0 && i < blkfill; i += inc) { + boolean_t newcontents = B_TRUE; + if (txg) { + int j; + newcontents = B_FALSE; + for (j = 0; j < dnp[i].dn_nblkptr; j++) { + if (dnp[i].dn_blkptr[j].blk_birth > txg) + newcontents = B_TRUE; + } + } + if (!dnp[i].dn_type == hole && newcontents) + break; + *offset += (1ULL << span) * inc; + } + if (i < 0 || i == blkfill) + error = ESRCH; + } else { + blkptr_t *bp = data; + span = (lvl - 1) * epbs + dn->dn_datablkshift; + minfill = 0; + maxfill = blkfill << ((lvl - 1) * epbs); + + if (hole) + maxfill--; + else + minfill++; + + for (i = (*offset >> span) & ((1ULL << epbs) - 1); + i >= 0 && i < epb; i += inc) { + if (bp[i].blk_fill >= minfill && + bp[i].blk_fill <= maxfill && + (hole || bp[i].blk_birth > txg)) + break; + if (inc < 0 && *offset < (1ULL << span)) + *offset = 0; + else + *offset += (1ULL << span) * inc; + } + if (i < 0 || i == epb) + error = ESRCH; + } + + if (db) + dbuf_rele(db, FTAG); + + return (error); +} + +/* + * Find the next hole, data, or sparse region at or after *offset. + * The value 'blkfill' tells us how many items we expect to find + * in an L0 data block; this value is 1 for normal objects, + * DNODES_PER_BLOCK for the meta dnode, and some fraction of + * DNODES_PER_BLOCK when searching for sparse regions thereof. + * + * Examples: + * + * dnode_next_offset(dn, flags, offset, 1, 1, 0); + * Finds the next/previous hole/data in a file. + * Used in dmu_offset_next(). + * + * dnode_next_offset(mdn, flags, offset, 0, DNODES_PER_BLOCK, txg); + * Finds the next free/allocated dnode an objset's meta-dnode. + * Only finds objects that have new contents since txg (ie. + * bonus buffer changes and content removal are ignored). + * Used in dmu_object_next(). + * + * dnode_next_offset(mdn, DNODE_FIND_HOLE, offset, 2, DNODES_PER_BLOCK >> 2, 0); + * Finds the next L2 meta-dnode bp that's at most 1/4 full. + * Used in dmu_object_alloc(). + */ +int +dnode_next_offset(dnode_t *dn, int flags, uint64_t *offset, + int minlvl, uint64_t blkfill, uint64_t txg) +{ + uint64_t initial_offset = *offset; + int lvl, maxlvl; + int error = 0; + + if (!(flags & DNODE_FIND_HAVELOCK)) + rw_enter(&dn->dn_struct_rwlock, RW_READER); + + if (dn->dn_phys->dn_nlevels == 0) { + error = ESRCH; + goto out; + } + + if (dn->dn_datablkshift == 0) { + if (*offset < dn->dn_datablksz) { + if (flags & DNODE_FIND_HOLE) + *offset = dn->dn_datablksz; + } else { + error = ESRCH; + } + goto out; + } + + maxlvl = dn->dn_phys->dn_nlevels; + + for (lvl = minlvl; lvl <= maxlvl; lvl++) { + error = dnode_next_offset_level(dn, + flags, offset, lvl, blkfill, txg); + if (error != ESRCH) + break; + } + + while (error == 0 && --lvl >= minlvl) { + error = dnode_next_offset_level(dn, + flags, offset, lvl, blkfill, txg); + } + + if (error == 0 && (flags & DNODE_FIND_BACKWARDS ? + initial_offset < *offset : initial_offset > *offset)) + error = ESRCH; +out: + if (!(flags & DNODE_FIND_HAVELOCK)) + rw_exit(&dn->dn_struct_rwlock); + + return (error); +} |