diff options
Diffstat (limited to 'sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu_tx.c')
| -rw-r--r-- | sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu_tx.c | 992 |
1 files changed, 992 insertions, 0 deletions
diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu_tx.c b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu_tx.c new file mode 100644 index 0000000..13fd8d4 --- /dev/null +++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu_tx.c @@ -0,0 +1,992 @@ +/* + * 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 2006 Sun Microsystems, Inc. All rights reserved. + * Use is subject to license terms. + */ + +#pragma ident "%Z%%M% %I% %E% SMI" + +#include <sys/dmu.h> +#include <sys/dmu_impl.h> +#include <sys/dbuf.h> +#include <sys/dmu_tx.h> +#include <sys/dmu_objset.h> +#include <sys/dsl_dataset.h> /* for dsl_dataset_block_freeable() */ +#include <sys/dsl_dir.h> /* for dsl_dir_tempreserve_*() */ +#include <sys/dsl_pool.h> +#include <sys/zap_impl.h> /* for fzap_default_block_shift */ +#include <sys/spa.h> +#include <sys/zfs_context.h> + +typedef void (*dmu_tx_hold_func_t)(dmu_tx_t *tx, struct dnode *dn, + uint64_t arg1, uint64_t arg2); + + +dmu_tx_t * +dmu_tx_create_dd(dsl_dir_t *dd) +{ + dmu_tx_t *tx = kmem_zalloc(sizeof (dmu_tx_t), KM_SLEEP); + tx->tx_dir = dd; + if (dd) + tx->tx_pool = dd->dd_pool; + list_create(&tx->tx_holds, sizeof (dmu_tx_hold_t), + offsetof(dmu_tx_hold_t, txh_node)); +#ifdef ZFS_DEBUG + refcount_create(&tx->tx_space_written); + refcount_create(&tx->tx_space_freed); +#endif + return (tx); +} + +dmu_tx_t * +dmu_tx_create(objset_t *os) +{ + dmu_tx_t *tx = dmu_tx_create_dd(os->os->os_dsl_dataset->ds_dir); + tx->tx_objset = os; + tx->tx_lastsnap_txg = dsl_dataset_prev_snap_txg(os->os->os_dsl_dataset); + return (tx); +} + +dmu_tx_t * +dmu_tx_create_assigned(struct dsl_pool *dp, uint64_t txg) +{ + dmu_tx_t *tx = dmu_tx_create_dd(NULL); + + ASSERT3U(txg, <=, dp->dp_tx.tx_open_txg); + tx->tx_pool = dp; + tx->tx_txg = txg; + tx->tx_anyobj = TRUE; + + return (tx); +} + +int +dmu_tx_is_syncing(dmu_tx_t *tx) +{ + return (tx->tx_anyobj); +} + +int +dmu_tx_private_ok(dmu_tx_t *tx) +{ + return (tx->tx_anyobj); +} + +static dmu_tx_hold_t * +dmu_tx_hold_object_impl(dmu_tx_t *tx, objset_t *os, uint64_t object, + enum dmu_tx_hold_type type, uint64_t arg1, uint64_t arg2) +{ + dmu_tx_hold_t *txh; + dnode_t *dn = NULL; + int err; + + if (object != DMU_NEW_OBJECT) { + err = dnode_hold(os->os, object, tx, &dn); + if (err) { + tx->tx_err = err; + return (NULL); + } + + if (err == 0 && tx->tx_txg != 0) { + mutex_enter(&dn->dn_mtx); + /* + * dn->dn_assigned_txg == tx->tx_txg doesn't pose a + * problem, but there's no way for it to happen (for + * now, at least). + */ + ASSERT(dn->dn_assigned_txg == 0); + dn->dn_assigned_txg = tx->tx_txg; + (void) refcount_add(&dn->dn_tx_holds, tx); + mutex_exit(&dn->dn_mtx); + } + } + + txh = kmem_zalloc(sizeof (dmu_tx_hold_t), KM_SLEEP); + txh->txh_tx = tx; + txh->txh_dnode = dn; +#ifdef ZFS_DEBUG + txh->txh_type = type; + txh->txh_arg1 = arg1; + txh->txh_arg2 = arg2; +#endif + list_insert_tail(&tx->tx_holds, txh); + + return (txh); +} + +void +dmu_tx_add_new_object(dmu_tx_t *tx, objset_t *os, uint64_t object) +{ + /* + * If we're syncing, they can manipulate any object anyhow, and + * the hold on the dnode_t can cause problems. + */ + if (!dmu_tx_is_syncing(tx)) { + (void) dmu_tx_hold_object_impl(tx, os, + object, THT_NEWOBJECT, 0, 0); + } +} + +static int +dmu_tx_check_ioerr(zio_t *zio, dnode_t *dn, int level, uint64_t blkid) +{ + int err; + dmu_buf_impl_t *db; + + rw_enter(&dn->dn_struct_rwlock, RW_READER); + db = dbuf_hold_level(dn, level, blkid, FTAG); + rw_exit(&dn->dn_struct_rwlock); + if (db == NULL) + return (EIO); + err = dbuf_read(db, zio, DB_RF_CANFAIL); + dbuf_rele(db, FTAG); + return (err); +} + +/* ARGSUSED */ +static void +dmu_tx_count_write(dmu_tx_hold_t *txh, uint64_t off, uint64_t len) +{ + dnode_t *dn = txh->txh_dnode; + uint64_t start, end, i; + int min_bs, max_bs, min_ibs, max_ibs, epbs, bits; + int err = 0; + + if (len == 0) + return; + + min_bs = SPA_MINBLOCKSHIFT; + max_bs = SPA_MAXBLOCKSHIFT; + min_ibs = DN_MIN_INDBLKSHIFT; + max_ibs = DN_MAX_INDBLKSHIFT; + + + /* + * For i/o error checking, read the first and last level-0 + * blocks (if they are not aligned), and all the level-1 blocks. + */ + + if (dn) { + if (dn->dn_maxblkid == 0) { + err = dmu_tx_check_ioerr(NULL, dn, 0, 0); + if (err) + goto out; + } else { + zio_t *zio = zio_root(dn->dn_objset->os_spa, + NULL, NULL, ZIO_FLAG_CANFAIL); + + /* first level-0 block */ + start = off >> dn->dn_datablkshift; + if (P2PHASE(off, dn->dn_datablksz) || + len < dn->dn_datablksz) { + err = dmu_tx_check_ioerr(zio, dn, 0, start); + if (err) + goto out; + } + + /* last level-0 block */ + end = (off+len-1) >> dn->dn_datablkshift; + if (end != start && + P2PHASE(off+len, dn->dn_datablksz)) { + err = dmu_tx_check_ioerr(zio, dn, 0, end); + if (err) + goto out; + } + + /* level-1 blocks */ + if (dn->dn_nlevels > 1) { + start >>= dn->dn_indblkshift - SPA_BLKPTRSHIFT; + end >>= dn->dn_indblkshift - SPA_BLKPTRSHIFT; + for (i = start+1; i < end; i++) { + err = dmu_tx_check_ioerr(zio, dn, 1, i); + if (err) + goto out; + } + } + + err = zio_wait(zio); + if (err) + goto out; + } + } + + /* + * If there's more than one block, the blocksize can't change, + * so we can make a more precise estimate. Alternatively, + * if the dnode's ibs is larger than max_ibs, always use that. + * This ensures that if we reduce DN_MAX_INDBLKSHIFT, + * the code will still work correctly on existing pools. + */ + if (dn && (dn->dn_maxblkid != 0 || dn->dn_indblkshift > max_ibs)) { + min_ibs = max_ibs = dn->dn_indblkshift; + if (dn->dn_datablkshift != 0) + min_bs = max_bs = dn->dn_datablkshift; + } + + /* + * 'end' is the last thing we will access, not one past. + * This way we won't overflow when accessing the last byte. + */ + start = P2ALIGN(off, 1ULL << max_bs); + end = P2ROUNDUP(off + len, 1ULL << max_bs) - 1; + txh->txh_space_towrite += end - start + 1; + + start >>= min_bs; + end >>= min_bs; + + epbs = min_ibs - SPA_BLKPTRSHIFT; + + /* + * The object contains at most 2^(64 - min_bs) blocks, + * and each indirect level maps 2^epbs. + */ + for (bits = 64 - min_bs; bits >= 0; bits -= epbs) { + start >>= epbs; + end >>= epbs; + /* + * If we increase the number of levels of indirection, + * we'll need new blkid=0 indirect blocks. If start == 0, + * we're already accounting for that blocks; and if end == 0, + * we can't increase the number of levels beyond that. + */ + if (start != 0 && end != 0) + txh->txh_space_towrite += 1ULL << max_ibs; + txh->txh_space_towrite += (end - start + 1) << max_ibs; + } + + ASSERT(txh->txh_space_towrite < 2 * DMU_MAX_ACCESS); + +out: + if (err) + txh->txh_tx->tx_err = err; +} + +static void +dmu_tx_count_dnode(dmu_tx_hold_t *txh) +{ + dnode_t *dn = txh->txh_dnode; + dnode_t *mdn = txh->txh_tx->tx_objset->os->os_meta_dnode; + uint64_t space = mdn->dn_datablksz + + ((mdn->dn_nlevels-1) << mdn->dn_indblkshift); + + if (dn && dn->dn_dbuf->db_blkptr && + dsl_dataset_block_freeable(dn->dn_objset->os_dsl_dataset, + dn->dn_dbuf->db_blkptr->blk_birth)) { + txh->txh_space_tooverwrite += space; + } else { + txh->txh_space_towrite += space; + } +} + +void +dmu_tx_hold_write(dmu_tx_t *tx, uint64_t object, uint64_t off, int len) +{ + dmu_tx_hold_t *txh; + + ASSERT(tx->tx_txg == 0); + ASSERT(len < DMU_MAX_ACCESS); + ASSERT(len == 0 || UINT64_MAX - off >= len - 1); + + txh = dmu_tx_hold_object_impl(tx, tx->tx_objset, + object, THT_WRITE, off, len); + if (txh == NULL) + return; + + dmu_tx_count_write(txh, off, len); + dmu_tx_count_dnode(txh); +} + +static void +dmu_tx_count_free(dmu_tx_hold_t *txh, uint64_t off, uint64_t len) +{ + uint64_t blkid, nblks; + uint64_t space = 0; + dnode_t *dn = txh->txh_dnode; + dsl_dataset_t *ds = dn->dn_objset->os_dsl_dataset; + spa_t *spa = txh->txh_tx->tx_pool->dp_spa; + int dirty; + + /* + * We don't need to use any locking to check for dirtyness + * because it's OK if we get stale data -- the dnode may become + * dirty immediately after our check anyway. This is just a + * means to avoid the expensive count when we aren't sure we + * need it. We need to be able to deal with a dirty dnode. + */ + dirty = list_link_active(&dn->dn_dirty_link[0]) | + list_link_active(&dn->dn_dirty_link[1]) | + list_link_active(&dn->dn_dirty_link[2]) | + list_link_active(&dn->dn_dirty_link[3]); + if (dirty || dn->dn_assigned_txg || dn->dn_phys->dn_nlevels == 0) + return; + + /* + * the struct_rwlock protects us against dn_phys->dn_nlevels + * changing, in case (against all odds) we manage to dirty & + * sync out the changes after we check for being dirty. + * also, dbuf_hold_impl() wants us to have the struct_rwlock. + * + * It's fine to use dn_datablkshift rather than the dn_phys + * equivalent because if it is changing, maxblkid==0 and we will + * bail. + */ + rw_enter(&dn->dn_struct_rwlock, RW_READER); + if (dn->dn_phys->dn_maxblkid == 0) { + if (off == 0 && len >= dn->dn_datablksz) { + blkid = 0; + nblks = 1; + } else { + rw_exit(&dn->dn_struct_rwlock); + return; + } + } else { + blkid = off >> dn->dn_datablkshift; + nblks = (off + len) >> dn->dn_datablkshift; + + if (blkid >= dn->dn_phys->dn_maxblkid) { + rw_exit(&dn->dn_struct_rwlock); + return; + } + if (blkid + nblks > dn->dn_phys->dn_maxblkid) + nblks = dn->dn_phys->dn_maxblkid - blkid; + + /* don't bother after 128,000 blocks */ + nblks = MIN(nblks, 128*1024); + } + + if (dn->dn_phys->dn_nlevels == 1) { + int i; + for (i = 0; i < nblks; i++) { + blkptr_t *bp = dn->dn_phys->dn_blkptr; + ASSERT3U(blkid + i, <, dn->dn_phys->dn_nblkptr); + bp += blkid + i; + if (dsl_dataset_block_freeable(ds, bp->blk_birth)) { + dprintf_bp(bp, "can free old%s", ""); + space += bp_get_dasize(spa, bp); + } + } + nblks = 0; + } + + while (nblks) { + dmu_buf_impl_t *dbuf; + int err, epbs, blkoff, tochk; + + epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT; + blkoff = P2PHASE(blkid, 1<<epbs); + tochk = MIN((1<<epbs) - blkoff, nblks); + + err = dbuf_hold_impl(dn, 1, blkid >> epbs, TRUE, FTAG, &dbuf); + if (err == 0) { + int i; + blkptr_t *bp; + + err = dbuf_read(dbuf, NULL, + DB_RF_HAVESTRUCT | DB_RF_CANFAIL); + if (err != 0) { + txh->txh_tx->tx_err = err; + dbuf_rele(dbuf, FTAG); + break; + } + + bp = dbuf->db.db_data; + bp += blkoff; + + for (i = 0; i < tochk; i++) { + if (dsl_dataset_block_freeable(ds, + bp[i].blk_birth)) { + dprintf_bp(&bp[i], + "can free old%s", ""); + space += bp_get_dasize(spa, &bp[i]); + } + } + dbuf_rele(dbuf, FTAG); + } + if (err && err != ENOENT) { + txh->txh_tx->tx_err = err; + break; + } + + blkid += tochk; + nblks -= tochk; + } + rw_exit(&dn->dn_struct_rwlock); + + txh->txh_space_tofree += space; +} + +void +dmu_tx_hold_free(dmu_tx_t *tx, uint64_t object, uint64_t off, uint64_t len) +{ + dmu_tx_hold_t *txh; + dnode_t *dn; + uint64_t start, end, i; + int err, shift; + zio_t *zio; + + ASSERT(tx->tx_txg == 0); + + txh = dmu_tx_hold_object_impl(tx, tx->tx_objset, + object, THT_FREE, off, len); + if (txh == NULL) + return; + dn = txh->txh_dnode; + + /* first block */ + if (off != 0) + dmu_tx_count_write(txh, off, 1); + /* last block */ + if (len != DMU_OBJECT_END) + dmu_tx_count_write(txh, off+len, 1); + + if (off >= (dn->dn_maxblkid+1) * dn->dn_datablksz) + return; + if (len == DMU_OBJECT_END) + len = (dn->dn_maxblkid+1) * dn->dn_datablksz - off; + + /* + * For i/o error checking, read the first and last level-0 + * blocks, and all the level-1 blocks. The above count_write's + * will take care of the level-0 blocks. + */ + if (dn->dn_nlevels > 1) { + shift = dn->dn_datablkshift + dn->dn_indblkshift - + SPA_BLKPTRSHIFT; + start = off >> shift; + end = dn->dn_datablkshift ? ((off+len) >> shift) : 0; + + zio = zio_root(tx->tx_pool->dp_spa, + NULL, NULL, ZIO_FLAG_CANFAIL); + for (i = start; i <= end; i++) { + uint64_t ibyte = i << shift; + err = dnode_next_offset(dn, FALSE, &ibyte, 2, 1, 0); + i = ibyte >> shift; + if (err == ESRCH) + break; + if (err) { + tx->tx_err = err; + return; + } + + err = dmu_tx_check_ioerr(zio, dn, 1, i); + if (err) { + tx->tx_err = err; + return; + } + } + err = zio_wait(zio); + if (err) { + tx->tx_err = err; + return; + } + } + + dmu_tx_count_dnode(txh); + dmu_tx_count_free(txh, off, len); +} + +void +dmu_tx_hold_zap(dmu_tx_t *tx, uint64_t object, int add, char *name) +{ + dmu_tx_hold_t *txh; + dnode_t *dn; + uint64_t nblocks; + int epbs, err; + + ASSERT(tx->tx_txg == 0); + + txh = dmu_tx_hold_object_impl(tx, tx->tx_objset, + object, THT_ZAP, add, (uintptr_t)name); + if (txh == NULL) + return; + dn = txh->txh_dnode; + + dmu_tx_count_dnode(txh); + + if (dn == NULL) { + /* + * We will be able to fit a new object's entries into one leaf + * block. So there will be at most 2 blocks total, + * including the header block. + */ + dmu_tx_count_write(txh, 0, 2 << fzap_default_block_shift); + return; + } + + ASSERT3P(dmu_ot[dn->dn_type].ot_byteswap, ==, zap_byteswap); + + if (dn->dn_maxblkid == 0 && !add) { + /* + * If there is only one block (i.e. this is a micro-zap) + * and we are not adding anything, the accounting is simple. + */ + err = dmu_tx_check_ioerr(NULL, dn, 0, 0); + if (err) { + tx->tx_err = err; + return; + } + + /* + * Use max block size here, since we don't know how much + * the size will change between now and the dbuf dirty call. + */ + if (dsl_dataset_block_freeable(dn->dn_objset->os_dsl_dataset, + dn->dn_phys->dn_blkptr[0].blk_birth)) + txh->txh_space_tooverwrite += SPA_MAXBLOCKSIZE; + else + txh->txh_space_towrite += SPA_MAXBLOCKSIZE; + return; + } + + if (dn->dn_maxblkid > 0 && name) { + /* + * access the name in this fat-zap so that we'll check + * for i/o errors to the leaf blocks, etc. + */ + err = zap_lookup(&dn->dn_objset->os, dn->dn_object, name, + 8, 0, NULL); + if (err == EIO) { + tx->tx_err = err; + return; + } + } + + /* + * 3 blocks overwritten: target leaf, ptrtbl block, header block + * 3 new blocks written if adding: new split leaf, 2 grown ptrtbl blocks + */ + dmu_tx_count_write(txh, dn->dn_maxblkid * dn->dn_datablksz, + (3 + add ? 3 : 0) << dn->dn_datablkshift); + + /* + * If the modified blocks are scattered to the four winds, + * we'll have to modify an indirect twig for each. + */ + epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT; + for (nblocks = dn->dn_maxblkid >> epbs; nblocks != 0; nblocks >>= epbs) + txh->txh_space_towrite += 3 << dn->dn_indblkshift; +} + +void +dmu_tx_hold_bonus(dmu_tx_t *tx, uint64_t object) +{ + dmu_tx_hold_t *txh; + + ASSERT(tx->tx_txg == 0); + + txh = dmu_tx_hold_object_impl(tx, tx->tx_objset, + object, THT_BONUS, 0, 0); + if (txh) + dmu_tx_count_dnode(txh); +} + +void +dmu_tx_hold_space(dmu_tx_t *tx, uint64_t space) +{ + dmu_tx_hold_t *txh; + ASSERT(tx->tx_txg == 0); + + txh = dmu_tx_hold_object_impl(tx, tx->tx_objset, + DMU_NEW_OBJECT, THT_SPACE, space, 0); + + txh->txh_space_towrite += space; +} + +int +dmu_tx_holds(dmu_tx_t *tx, uint64_t object) +{ + dmu_tx_hold_t *txh; + int holds = 0; + + /* + * By asserting that the tx is assigned, we're counting the + * number of dn_tx_holds, which is the same as the number of + * dn_holds. Otherwise, we'd be counting dn_holds, but + * dn_tx_holds could be 0. + */ + ASSERT(tx->tx_txg != 0); + + /* if (tx->tx_anyobj == TRUE) */ + /* return (0); */ + + for (txh = list_head(&tx->tx_holds); txh; + txh = list_next(&tx->tx_holds, txh)) { + if (txh->txh_dnode && txh->txh_dnode->dn_object == object) + holds++; + } + + return (holds); +} + +#ifdef ZFS_DEBUG +void +dmu_tx_dirty_buf(dmu_tx_t *tx, dmu_buf_impl_t *db) +{ + dmu_tx_hold_t *txh; + int match_object = FALSE, match_offset = FALSE; + dnode_t *dn = db->db_dnode; + + ASSERT(tx->tx_txg != 0); + ASSERT(tx->tx_objset == NULL || dn->dn_objset == tx->tx_objset->os); + ASSERT3U(dn->dn_object, ==, db->db.db_object); + + if (tx->tx_anyobj) + return; + + /* XXX No checking on the meta dnode for now */ + if (db->db.db_object == DMU_META_DNODE_OBJECT) + return; + + for (txh = list_head(&tx->tx_holds); txh; + txh = list_next(&tx->tx_holds, txh)) { + ASSERT(dn == NULL || dn->dn_assigned_txg == tx->tx_txg); + if (txh->txh_dnode == dn && txh->txh_type != THT_NEWOBJECT) + match_object = TRUE; + if (txh->txh_dnode == NULL || txh->txh_dnode == dn) { + int datablkshift = dn->dn_datablkshift ? + dn->dn_datablkshift : SPA_MAXBLOCKSHIFT; + int epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT; + int shift = datablkshift + epbs * db->db_level; + uint64_t beginblk = shift >= 64 ? 0 : + (txh->txh_arg1 >> shift); + uint64_t endblk = shift >= 64 ? 0 : + ((txh->txh_arg1 + txh->txh_arg2 - 1) >> shift); + uint64_t blkid = db->db_blkid; + + /* XXX txh_arg2 better not be zero... */ + + dprintf("found txh type %x beginblk=%llx endblk=%llx\n", + txh->txh_type, beginblk, endblk); + + switch (txh->txh_type) { + case THT_WRITE: + if (blkid >= beginblk && blkid <= endblk) + match_offset = TRUE; + /* + * We will let this hold work for the bonus + * buffer so that we don't need to hold it + * when creating a new object. + */ + if (blkid == DB_BONUS_BLKID) + match_offset = TRUE; + /* + * They might have to increase nlevels, + * thus dirtying the new TLIBs. Or the + * might have to change the block size, + * thus dirying the new lvl=0 blk=0. + */ + if (blkid == 0) + match_offset = TRUE; + break; + case THT_FREE: + if (blkid == beginblk && + (txh->txh_arg1 != 0 || + dn->dn_maxblkid == 0)) + match_offset = TRUE; + if (blkid == endblk && + txh->txh_arg2 != DMU_OBJECT_END) + match_offset = TRUE; + break; + case THT_BONUS: + if (blkid == DB_BONUS_BLKID) + match_offset = TRUE; + break; + case THT_ZAP: + match_offset = TRUE; + break; + case THT_NEWOBJECT: + match_object = TRUE; + break; + default: + ASSERT(!"bad txh_type"); + } + } + if (match_object && match_offset) + return; + } + panic("dirtying dbuf obj=%llx lvl=%u blkid=%llx but not tx_held\n", + (u_longlong_t)db->db.db_object, db->db_level, + (u_longlong_t)db->db_blkid); +} +#endif + +static int +dmu_tx_try_assign(dmu_tx_t *tx, uint64_t txg_how) +{ + dmu_tx_hold_t *txh; + uint64_t lsize, asize, fsize, towrite, tofree, tooverwrite; + + ASSERT3U(tx->tx_txg, ==, 0); + if (tx->tx_err) + return (tx->tx_err); + + tx->tx_txg = txg_hold_open(tx->tx_pool, &tx->tx_txgh); + tx->tx_needassign_txh = NULL; + + /* + * NB: No error returns are allowed after txg_hold_open, but + * before processing the dnode holds, due to the + * dmu_tx_unassign() logic. + */ + + towrite = tofree = tooverwrite = 0; + for (txh = list_head(&tx->tx_holds); txh; + txh = list_next(&tx->tx_holds, txh)) { + dnode_t *dn = txh->txh_dnode; + if (dn != NULL) { + mutex_enter(&dn->dn_mtx); + if (dn->dn_assigned_txg == tx->tx_txg - 1) { + mutex_exit(&dn->dn_mtx); + tx->tx_needassign_txh = txh; + return (ERESTART); + } + if (dn->dn_assigned_txg == 0) + dn->dn_assigned_txg = tx->tx_txg; + ASSERT3U(dn->dn_assigned_txg, ==, tx->tx_txg); + (void) refcount_add(&dn->dn_tx_holds, tx); + mutex_exit(&dn->dn_mtx); + } + towrite += txh->txh_space_towrite; + tofree += txh->txh_space_tofree; + tooverwrite += txh->txh_space_tooverwrite; + } + + /* + * NB: This check must be after we've held the dnodes, so that + * the dmu_tx_unassign() logic will work properly + */ + if (txg_how >= TXG_INITIAL && txg_how != tx->tx_txg) + return (ERESTART); + + /* + * If a snapshot has been taken since we made our estimates, + * assume that we won't be able to free or overwrite anything. + */ + if (tx->tx_objset && + dsl_dataset_prev_snap_txg(tx->tx_objset->os->os_dsl_dataset) > + tx->tx_lastsnap_txg) { + towrite += tooverwrite; + tooverwrite = tofree = 0; + } + + /* + * Convert logical size to worst-case allocated size. + */ + fsize = spa_get_asize(tx->tx_pool->dp_spa, tooverwrite) + tofree; + lsize = towrite + tooverwrite; + asize = spa_get_asize(tx->tx_pool->dp_spa, lsize); + +#ifdef ZFS_DEBUG + tx->tx_space_towrite = asize; + tx->tx_space_tofree = tofree; + tx->tx_space_tooverwrite = tooverwrite; +#endif + + if (tx->tx_dir && asize != 0) { + int err = dsl_dir_tempreserve_space(tx->tx_dir, + lsize, asize, fsize, &tx->tx_tempreserve_cookie, tx); + if (err) + return (err); + } + + return (0); +} + +static void +dmu_tx_unassign(dmu_tx_t *tx) +{ + dmu_tx_hold_t *txh; + + if (tx->tx_txg == 0) + return; + + txg_rele_to_quiesce(&tx->tx_txgh); + + for (txh = list_head(&tx->tx_holds); txh != tx->tx_needassign_txh; + txh = list_next(&tx->tx_holds, txh)) { + dnode_t *dn = txh->txh_dnode; + + if (dn == NULL) + continue; + mutex_enter(&dn->dn_mtx); + ASSERT3U(dn->dn_assigned_txg, ==, tx->tx_txg); + + if (refcount_remove(&dn->dn_tx_holds, tx) == 0) { + dn->dn_assigned_txg = 0; + cv_broadcast(&dn->dn_notxholds); + } + mutex_exit(&dn->dn_mtx); + } + + txg_rele_to_sync(&tx->tx_txgh); + + tx->tx_lasttried_txg = tx->tx_txg; + tx->tx_txg = 0; +} + +/* + * Assign tx to a transaction group. txg_how can be one of: + * + * (1) TXG_WAIT. If the current open txg is full, waits until there's + * a new one. This should be used when you're not holding locks. + * If will only fail if we're truly out of space (or over quota). + * + * (2) TXG_NOWAIT. If we can't assign into the current open txg without + * blocking, returns immediately with ERESTART. This should be used + * whenever you're holding locks. On an ERESTART error, the caller + * should drop locks, do a dmu_tx_wait(tx), and try again. + * + * (3) A specific txg. Use this if you need to ensure that multiple + * transactions all sync in the same txg. Like TXG_NOWAIT, it + * returns ERESTART if it can't assign you into the requested txg. + */ +int +dmu_tx_assign(dmu_tx_t *tx, uint64_t txg_how) +{ + int err; + + ASSERT(tx->tx_txg == 0); + ASSERT(txg_how != 0); + ASSERT(!dsl_pool_sync_context(tx->tx_pool)); + + while ((err = dmu_tx_try_assign(tx, txg_how)) != 0) { + dmu_tx_unassign(tx); + + if (err != ERESTART || txg_how != TXG_WAIT) + return (err); + + dmu_tx_wait(tx); + } + + txg_rele_to_quiesce(&tx->tx_txgh); + + return (0); +} + +void +dmu_tx_wait(dmu_tx_t *tx) +{ + ASSERT(tx->tx_txg == 0); + ASSERT(tx->tx_lasttried_txg != 0); + + if (tx->tx_needassign_txh) { + dnode_t *dn = tx->tx_needassign_txh->txh_dnode; + + mutex_enter(&dn->dn_mtx); + while (dn->dn_assigned_txg == tx->tx_lasttried_txg - 1) + cv_wait(&dn->dn_notxholds, &dn->dn_mtx); + mutex_exit(&dn->dn_mtx); + tx->tx_needassign_txh = NULL; + } else { + txg_wait_open(tx->tx_pool, tx->tx_lasttried_txg + 1); + } +} + +void +dmu_tx_willuse_space(dmu_tx_t *tx, int64_t delta) +{ +#ifdef ZFS_DEBUG + if (tx->tx_dir == NULL || delta == 0) + return; + + if (delta > 0) { + ASSERT3U(refcount_count(&tx->tx_space_written) + delta, <=, + tx->tx_space_towrite); + (void) refcount_add_many(&tx->tx_space_written, delta, NULL); + } else { + (void) refcount_add_many(&tx->tx_space_freed, -delta, NULL); + } +#endif +} + +void +dmu_tx_commit(dmu_tx_t *tx) +{ + dmu_tx_hold_t *txh; + + ASSERT(tx->tx_txg != 0); + + while (txh = list_head(&tx->tx_holds)) { + dnode_t *dn = txh->txh_dnode; + + list_remove(&tx->tx_holds, txh); + kmem_free(txh, sizeof (dmu_tx_hold_t)); + if (dn == NULL) + continue; + mutex_enter(&dn->dn_mtx); + ASSERT3U(dn->dn_assigned_txg, ==, tx->tx_txg); + + if (refcount_remove(&dn->dn_tx_holds, tx) == 0) { + dn->dn_assigned_txg = 0; + cv_broadcast(&dn->dn_notxholds); + } + mutex_exit(&dn->dn_mtx); + dnode_rele(dn, tx); + } + + if (tx->tx_tempreserve_cookie) + dsl_dir_tempreserve_clear(tx->tx_tempreserve_cookie, tx); + + if (tx->tx_anyobj == FALSE) + txg_rele_to_sync(&tx->tx_txgh); +#ifdef ZFS_DEBUG + dprintf("towrite=%llu written=%llu tofree=%llu freed=%llu\n", + tx->tx_space_towrite, refcount_count(&tx->tx_space_written), + tx->tx_space_tofree, refcount_count(&tx->tx_space_freed)); + refcount_destroy_many(&tx->tx_space_written, + refcount_count(&tx->tx_space_written)); + refcount_destroy_many(&tx->tx_space_freed, + refcount_count(&tx->tx_space_freed)); +#endif + kmem_free(tx, sizeof (dmu_tx_t)); +} + +void +dmu_tx_abort(dmu_tx_t *tx) +{ + dmu_tx_hold_t *txh; + + ASSERT(tx->tx_txg == 0); + + while (txh = list_head(&tx->tx_holds)) { + dnode_t *dn = txh->txh_dnode; + + list_remove(&tx->tx_holds, txh); + kmem_free(txh, sizeof (dmu_tx_hold_t)); + if (dn != NULL) + dnode_rele(dn, tx); + } +#ifdef ZFS_DEBUG + refcount_destroy_many(&tx->tx_space_written, + refcount_count(&tx->tx_space_written)); + refcount_destroy_many(&tx->tx_space_freed, + refcount_count(&tx->tx_space_freed)); +#endif + kmem_free(tx, sizeof (dmu_tx_t)); +} + +uint64_t +dmu_tx_get_txg(dmu_tx_t *tx) +{ + ASSERT(tx->tx_txg != 0); + return (tx->tx_txg); +} |
