zfs_rename: support RENAME_* flags

[mirror_zfs.git] / module / zfs / zfs_log.c

/*
 * 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) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
 * Copyright (c) 2015, 2018 by Delphix. All rights reserved.
 */


#include <sys/types.h>
#include <sys/param.h>
#include <sys/sysmacros.h>
#include <sys/cmn_err.h>
#include <sys/kmem.h>
#include <sys/thread.h>
#include <sys/file.h>
#include <sys/vfs.h>
#include <sys/zfs_znode.h>
#include <sys/zfs_dir.h>
#include <sys/zil.h>
#include <sys/zil_impl.h>
#include <sys/byteorder.h>
#include <sys/policy.h>
#include <sys/stat.h>
#include <sys/acl.h>
#include <sys/dmu.h>
#include <sys/dbuf.h>
#include <sys/spa.h>
#include <sys/zfs_fuid.h>
#include <sys/dsl_dataset.h>

/*
 * These zfs_log_* functions must be called within a dmu tx, in one
 * of 2 contexts depending on zilog->z_replay:
 *
 * Non replay mode
 * ---------------
 * We need to record the transaction so that if it is committed to
 * the Intent Log then it can be replayed.  An intent log transaction
 * structure (itx_t) is allocated and all the information necessary to
 * possibly replay the transaction is saved in it. The itx is then assigned
 * a sequence number and inserted in the in-memory list anchored in the zilog.
 *
 * Replay mode
 * -----------
 * We need to mark the intent log record as replayed in the log header.
 * This is done in the same transaction as the replay so that they
 * commit atomically.
 */

int
zfs_log_create_txtype(zil_create_t type, vsecattr_t *vsecp, vattr_t *vap)
{
        int isxvattr = (vap->va_mask & ATTR_XVATTR);
        switch (type) {
        case Z_FILE:
                if (vsecp == NULL && !isxvattr)
                        return (TX_CREATE);
                if (vsecp && isxvattr)
                        return (TX_CREATE_ACL_ATTR);
                if (vsecp)
                        return (TX_CREATE_ACL);
                else
                        return (TX_CREATE_ATTR);
        case Z_DIR:
                if (vsecp == NULL && !isxvattr)
                        return (TX_MKDIR);
                if (vsecp && isxvattr)
                        return (TX_MKDIR_ACL_ATTR);
                if (vsecp)
                        return (TX_MKDIR_ACL);
                else
                        return (TX_MKDIR_ATTR);
        case Z_XATTRDIR:
                return (TX_MKXATTR);
        }
        ASSERT(0);
        return (TX_MAX_TYPE);
}

/*
 * build up the log data necessary for logging xvattr_t
 * First lr_attr_t is initialized.  following the lr_attr_t
 * is the mapsize and attribute bitmap copied from the xvattr_t.
 * Following the bitmap and bitmapsize two 64 bit words are reserved
 * for the create time which may be set.  Following the create time
 * records a single 64 bit integer which has the bits to set on
 * replay for the xvattr.
 */
static void
zfs_log_xvattr(lr_attr_t *lrattr, xvattr_t *xvap)
{
        xoptattr_t *xoap;

        xoap = xva_getxoptattr(xvap);
        ASSERT(xoap);

        lrattr->lr_attr_masksize = xvap->xva_mapsize;
        uint32_t *bitmap = &lrattr->lr_attr_bitmap;
        for (int i = 0; i != xvap->xva_mapsize; i++, bitmap++)
                *bitmap = xvap->xva_reqattrmap[i];

        lr_attr_end_t *end = (lr_attr_end_t *)bitmap;
        end->lr_attr_attrs = 0;
        end->lr_attr_crtime[0] = 0;
        end->lr_attr_crtime[1] = 0;
        memset(end->lr_attr_scanstamp, 0, AV_SCANSTAMP_SZ);

        if (XVA_ISSET_REQ(xvap, XAT_READONLY))
                end->lr_attr_attrs |= (xoap->xoa_readonly == 0) ? 0 :
                    XAT0_READONLY;
        if (XVA_ISSET_REQ(xvap, XAT_HIDDEN))
                end->lr_attr_attrs |= (xoap->xoa_hidden == 0) ? 0 :
                    XAT0_HIDDEN;
        if (XVA_ISSET_REQ(xvap, XAT_SYSTEM))
                end->lr_attr_attrs |= (xoap->xoa_system == 0) ? 0 :
                    XAT0_SYSTEM;
        if (XVA_ISSET_REQ(xvap, XAT_ARCHIVE))
                end->lr_attr_attrs |= (xoap->xoa_archive == 0) ? 0 :
                    XAT0_ARCHIVE;
        if (XVA_ISSET_REQ(xvap, XAT_IMMUTABLE))
                end->lr_attr_attrs |= (xoap->xoa_immutable == 0) ? 0 :
                    XAT0_IMMUTABLE;
        if (XVA_ISSET_REQ(xvap, XAT_NOUNLINK))
                end->lr_attr_attrs |= (xoap->xoa_nounlink == 0) ? 0 :
                    XAT0_NOUNLINK;
        if (XVA_ISSET_REQ(xvap, XAT_APPENDONLY))
                end->lr_attr_attrs |= (xoap->xoa_appendonly == 0) ? 0 :
                    XAT0_APPENDONLY;
        if (XVA_ISSET_REQ(xvap, XAT_OPAQUE))
                end->lr_attr_attrs |= (xoap->xoa_opaque == 0) ? 0 :
                    XAT0_APPENDONLY;
        if (XVA_ISSET_REQ(xvap, XAT_NODUMP))
                end->lr_attr_attrs |= (xoap->xoa_nodump == 0) ? 0 :
                    XAT0_NODUMP;
        if (XVA_ISSET_REQ(xvap, XAT_AV_QUARANTINED))
                end->lr_attr_attrs |= (xoap->xoa_av_quarantined == 0) ? 0 :
                    XAT0_AV_QUARANTINED;
        if (XVA_ISSET_REQ(xvap, XAT_AV_MODIFIED))
                end->lr_attr_attrs |= (xoap->xoa_av_modified == 0) ? 0 :
                    XAT0_AV_MODIFIED;
        if (XVA_ISSET_REQ(xvap, XAT_CREATETIME))
                ZFS_TIME_ENCODE(&xoap->xoa_createtime, end->lr_attr_crtime);
        if (XVA_ISSET_REQ(xvap, XAT_AV_SCANSTAMP)) {
                ASSERT(!XVA_ISSET_REQ(xvap, XAT_PROJID));

                memcpy(end->lr_attr_scanstamp, xoap->xoa_av_scanstamp,
                    AV_SCANSTAMP_SZ);
        } else if (XVA_ISSET_REQ(xvap, XAT_PROJID)) {
                /*
                 * XAT_PROJID and XAT_AV_SCANSTAMP will never be valid
                 * at the same time, so we can share the same space.
                 */
                memcpy(end->lr_attr_scanstamp, &xoap->xoa_projid,
                    sizeof (uint64_t));
        }
        if (XVA_ISSET_REQ(xvap, XAT_REPARSE))
                end->lr_attr_attrs |= (xoap->xoa_reparse == 0) ? 0 :
                    XAT0_REPARSE;
        if (XVA_ISSET_REQ(xvap, XAT_OFFLINE))
                end->lr_attr_attrs |= (xoap->xoa_offline == 0) ? 0 :
                    XAT0_OFFLINE;
        if (XVA_ISSET_REQ(xvap, XAT_SPARSE))
                end->lr_attr_attrs |= (xoap->xoa_sparse == 0) ? 0 :
                    XAT0_SPARSE;
        if (XVA_ISSET_REQ(xvap, XAT_PROJINHERIT))
                end->lr_attr_attrs |= (xoap->xoa_projinherit == 0) ? 0 :
                    XAT0_PROJINHERIT;
}

static void *
zfs_log_fuid_ids(zfs_fuid_info_t *fuidp, void *start)
{
        zfs_fuid_t *zfuid;
        uint64_t *fuidloc = start;

        /* First copy in the ACE FUIDs */
        for (zfuid = list_head(&fuidp->z_fuids); zfuid;
            zfuid = list_next(&fuidp->z_fuids, zfuid)) {
                *fuidloc++ = zfuid->z_logfuid;
        }
        return (fuidloc);
}


static void *
zfs_log_fuid_domains(zfs_fuid_info_t *fuidp, void *start)
{
        zfs_fuid_domain_t *zdomain;

        /* now copy in the domain info, if any */
        if (fuidp->z_domain_str_sz != 0) {
                for (zdomain = list_head(&fuidp->z_domains); zdomain;
                    zdomain = list_next(&fuidp->z_domains, zdomain)) {
                        memcpy(start, zdomain->z_domain,
                            strlen(zdomain->z_domain) + 1);
                        start = (caddr_t)start +
                            strlen(zdomain->z_domain) + 1;
                }
        }
        return (start);
}

/*
 * If zp is an xattr node, check whether the xattr owner is unlinked.
 * We don't want to log anything if the owner is unlinked.
 */
static int
zfs_xattr_owner_unlinked(znode_t *zp)
{
        int unlinked = 0;
        znode_t *dzp;
#ifdef __FreeBSD__
        znode_t *tzp = zp;

        /*
         * zrele drops the vnode lock which violates the VOP locking contract
         * on FreeBSD. See comment at the top of zfs_replay.c for more detail.
         */
        /*
         * if zp is XATTR node, keep walking up via z_xattr_parent until we
         * get the owner
         */
        while (tzp->z_pflags & ZFS_XATTR) {
                ASSERT3U(zp->z_xattr_parent, !=, 0);
                if (zfs_zget(ZTOZSB(tzp), tzp->z_xattr_parent, &dzp) != 0) {
                        unlinked = 1;
                        break;
                }

                if (tzp != zp)
                        zrele(tzp);
                tzp = dzp;
                unlinked = tzp->z_unlinked;
        }
        if (tzp != zp)
                zrele(tzp);
#else
        zhold(zp);
        /*
         * if zp is XATTR node, keep walking up via z_xattr_parent until we
         * get the owner
         */
        while (zp->z_pflags & ZFS_XATTR) {
                ASSERT3U(zp->z_xattr_parent, !=, 0);
                if (zfs_zget(ZTOZSB(zp), zp->z_xattr_parent, &dzp) != 0) {
                        unlinked = 1;
                        break;
                }

                zrele(zp);
                zp = dzp;
                unlinked = zp->z_unlinked;
        }
        zrele(zp);
#endif
        return (unlinked);
}

/*
 * Handles TX_CREATE, TX_CREATE_ATTR, TX_MKDIR, TX_MKDIR_ATTR and
 * TK_MKXATTR transactions.
 *
 * TX_CREATE and TX_MKDIR are standard creates, but they may have FUID
 * domain information appended prior to the name.  In this case the
 * uid/gid in the log record will be a log centric FUID.
 *
 * TX_CREATE_ACL_ATTR and TX_MKDIR_ACL_ATTR handle special creates that
 * may contain attributes, ACL and optional fuid information.
 *
 * TX_CREATE_ACL and TX_MKDIR_ACL handle special creates that specify
 * and ACL and normal users/groups in the ACEs.
 *
 * There may be an optional xvattr attribute information similar
 * to zfs_log_setattr.
 *
 * Also, after the file name "domain" strings may be appended.
 */
void
zfs_log_create(zilog_t *zilog, dmu_tx_t *tx, uint64_t txtype,
    znode_t *dzp, znode_t *zp, const char *name, vsecattr_t *vsecp,
    zfs_fuid_info_t *fuidp, vattr_t *vap)
{
        itx_t *itx;
        lr_create_t *lr;
        lr_acl_create_t *lracl;
        size_t aclsize = 0;
        size_t xvatsize = 0;
        size_t txsize;
        xvattr_t *xvap = (xvattr_t *)vap;
        void *end;
        size_t lrsize;
        size_t namesize = strlen(name) + 1;
        size_t fuidsz = 0;

        if (zil_replaying(zilog, tx) || zfs_xattr_owner_unlinked(dzp))
                return;

        /*
         * If we have FUIDs present then add in space for
         * domains and ACE fuid's if any.
         */
        if (fuidp) {
                fuidsz += fuidp->z_domain_str_sz;
                fuidsz += fuidp->z_fuid_cnt * sizeof (uint64_t);
        }

        if (vap->va_mask & ATTR_XVATTR)
                xvatsize = ZIL_XVAT_SIZE(xvap->xva_mapsize);

        if ((int)txtype == TX_CREATE_ATTR || (int)txtype == TX_MKDIR_ATTR ||
            (int)txtype == TX_CREATE || (int)txtype == TX_MKDIR ||
            (int)txtype == TX_MKXATTR) {
                txsize = sizeof (*lr) + namesize + fuidsz + xvatsize;
                lrsize = sizeof (*lr);
        } else {
                txsize =
                    sizeof (lr_acl_create_t) + namesize + fuidsz +
                    ZIL_ACE_LENGTH(aclsize) + xvatsize;
                lrsize = sizeof (lr_acl_create_t);
        }

        itx = zil_itx_create(txtype, txsize);

        lr = (lr_create_t *)&itx->itx_lr;
        lr->lr_doid = dzp->z_id;
        lr->lr_foid = zp->z_id;
        /* Store dnode slot count in 8 bits above object id. */
        LR_FOID_SET_SLOTS(lr->lr_foid, zp->z_dnodesize >> DNODE_SHIFT);
        lr->lr_mode = zp->z_mode;
        if (!IS_EPHEMERAL(KUID_TO_SUID(ZTOUID(zp)))) {
                lr->lr_uid = (uint64_t)KUID_TO_SUID(ZTOUID(zp));
        } else {
                lr->lr_uid = fuidp->z_fuid_owner;
        }
        if (!IS_EPHEMERAL(KGID_TO_SGID(ZTOGID(zp)))) {
                lr->lr_gid = (uint64_t)KGID_TO_SGID(ZTOGID(zp));
        } else {
                lr->lr_gid = fuidp->z_fuid_group;
        }
        (void) sa_lookup(zp->z_sa_hdl, SA_ZPL_GEN(ZTOZSB(zp)), &lr->lr_gen,
            sizeof (uint64_t));
        (void) sa_lookup(zp->z_sa_hdl, SA_ZPL_CRTIME(ZTOZSB(zp)),
            lr->lr_crtime, sizeof (uint64_t) * 2);

        if (sa_lookup(zp->z_sa_hdl, SA_ZPL_RDEV(ZTOZSB(zp)), &lr->lr_rdev,
            sizeof (lr->lr_rdev)) != 0)
                lr->lr_rdev = 0;

        /*
         * Fill in xvattr info if any
         */
        if (vap->va_mask & ATTR_XVATTR) {
                zfs_log_xvattr((lr_attr_t *)((caddr_t)lr + lrsize), xvap);
                end = (caddr_t)lr + lrsize + xvatsize;
        } else {
                end = (caddr_t)lr + lrsize;
        }

        /* Now fill in any ACL info */

        if (vsecp) {
                lracl = (lr_acl_create_t *)&itx->itx_lr;
                lracl->lr_aclcnt = vsecp->vsa_aclcnt;
                lracl->lr_acl_bytes = aclsize;
                lracl->lr_domcnt = fuidp ? fuidp->z_domain_cnt : 0;
                lracl->lr_fuidcnt  = fuidp ? fuidp->z_fuid_cnt : 0;
                if (vsecp->vsa_aclflags & VSA_ACE_ACLFLAGS)
                        lracl->lr_acl_flags = (uint64_t)vsecp->vsa_aclflags;
                else
                        lracl->lr_acl_flags = 0;

                memcpy(end, vsecp->vsa_aclentp, aclsize);
                end = (caddr_t)end + ZIL_ACE_LENGTH(aclsize);
        }

        /* drop in FUID info */
        if (fuidp) {
                end = zfs_log_fuid_ids(fuidp, end);
                end = zfs_log_fuid_domains(fuidp, end);
        }
        /*
         * Now place file name in log record
         */
        memcpy(end, name, namesize);

        zil_itx_assign(zilog, itx, tx);
}

/*
 * Handles both TX_REMOVE and TX_RMDIR transactions.
 */
void
zfs_log_remove(zilog_t *zilog, dmu_tx_t *tx, uint64_t txtype,
    znode_t *dzp, const char *name, uint64_t foid, boolean_t unlinked)
{
        itx_t *itx;
        lr_remove_t *lr;
        size_t namesize = strlen(name) + 1;

        if (zil_replaying(zilog, tx) || zfs_xattr_owner_unlinked(dzp))
                return;

        itx = zil_itx_create(txtype, sizeof (*lr) + namesize);
        lr = (lr_remove_t *)&itx->itx_lr;
        lr->lr_doid = dzp->z_id;
        memcpy(lr + 1, name, namesize);

        itx->itx_oid = foid;

        /*
         * Object ids can be re-instantiated in the next txg so
         * remove any async transactions to avoid future leaks.
         * This can happen if a fsync occurs on the re-instantiated
         * object for a WR_INDIRECT or WR_NEED_COPY write, which gets
         * the new file data and flushes a write record for the old object.
         */
        if (unlinked) {
                ASSERT((txtype & ~TX_CI) == TX_REMOVE);
                zil_remove_async(zilog, foid);
        }
        zil_itx_assign(zilog, itx, tx);
}

/*
 * Handles TX_LINK transactions.
 */
void
zfs_log_link(zilog_t *zilog, dmu_tx_t *tx, uint64_t txtype,
    znode_t *dzp, znode_t *zp, const char *name)
{
        itx_t *itx;
        lr_link_t *lr;
        size_t namesize = strlen(name) + 1;

        if (zil_replaying(zilog, tx))
                return;

        itx = zil_itx_create(txtype, sizeof (*lr) + namesize);
        lr = (lr_link_t *)&itx->itx_lr;
        lr->lr_doid = dzp->z_id;
        lr->lr_link_obj = zp->z_id;
        memcpy(lr + 1, name, namesize);

        zil_itx_assign(zilog, itx, tx);
}

/*
 * Handles TX_SYMLINK transactions.
 */
void
zfs_log_symlink(zilog_t *zilog, dmu_tx_t *tx, uint64_t txtype,
    znode_t *dzp, znode_t *zp, const char *name, const char *link)
{
        itx_t *itx;
        lr_create_t *lr;
        size_t namesize = strlen(name) + 1;
        size_t linksize = strlen(link) + 1;

        if (zil_replaying(zilog, tx))
                return;

        itx = zil_itx_create(txtype, sizeof (*lr) + namesize + linksize);
        lr = (lr_create_t *)&itx->itx_lr;
        lr->lr_doid = dzp->z_id;
        lr->lr_foid = zp->z_id;
        lr->lr_uid = KUID_TO_SUID(ZTOUID(zp));
        lr->lr_gid = KGID_TO_SGID(ZTOGID(zp));
        lr->lr_mode = zp->z_mode;
        (void) sa_lookup(zp->z_sa_hdl, SA_ZPL_GEN(ZTOZSB(zp)), &lr->lr_gen,
            sizeof (uint64_t));
        (void) sa_lookup(zp->z_sa_hdl, SA_ZPL_CRTIME(ZTOZSB(zp)),
            lr->lr_crtime, sizeof (uint64_t) * 2);
        memcpy((char *)(lr + 1), name, namesize);
        memcpy((char *)(lr + 1) + namesize, link, linksize);

        zil_itx_assign(zilog, itx, tx);
}

static void
do_zfs_log_rename(zilog_t *zilog, dmu_tx_t *tx, uint64_t txtype, znode_t *sdzp,
    const char *sname, znode_t *tdzp, const char *dname, znode_t *szp)
{
        itx_t *itx;
        lr_rename_t *lr;
        size_t snamesize = strlen(sname) + 1;
        size_t dnamesize = strlen(dname) + 1;

        if (zil_replaying(zilog, tx))
                return;

        itx = zil_itx_create(txtype, sizeof (*lr) + snamesize + dnamesize);
        lr = (lr_rename_t *)&itx->itx_lr;
        lr->lr_sdoid = sdzp->z_id;
        lr->lr_tdoid = tdzp->z_id;
        memcpy((char *)(lr + 1), sname, snamesize);
        memcpy((char *)(lr + 1) + snamesize, dname, dnamesize);
        itx->itx_oid = szp->z_id;

        zil_itx_assign(zilog, itx, tx);
}

/*
 * Handles TX_RENAME transactions.
 */
void
zfs_log_rename(zilog_t *zilog, dmu_tx_t *tx, uint64_t txtype, znode_t *sdzp,
    const char *sname, znode_t *tdzp, const char *dname, znode_t *szp)
{
        txtype |= TX_RENAME;
        do_zfs_log_rename(zilog, tx, txtype, sdzp, sname, tdzp, dname, szp);
}

/*
 * Handles TX_RENAME_EXCHANGE transactions.
 */
void
zfs_log_rename_exchange(zilog_t *zilog, dmu_tx_t *tx, uint64_t txtype,
    znode_t *sdzp, const char *sname, znode_t *tdzp, const char *dname,
    znode_t *szp)
{
        txtype |= TX_RENAME_EXCHANGE;
        do_zfs_log_rename(zilog, tx, txtype, sdzp, sname, tdzp, dname, szp);
}

/*
 * Handles TX_RENAME_WHITEOUT transactions.
 *
 * Unfortunately we cannot reuse do_zfs_log_rename because we we need to call
 * zfs_mknode() on replay which requires stashing bits as with TX_CREATE.
 */
void
zfs_log_rename_whiteout(zilog_t *zilog, dmu_tx_t *tx, uint64_t txtype,
    znode_t *sdzp, const char *sname, znode_t *tdzp, const char *dname,
    znode_t *szp, znode_t *wzp)
{
        itx_t *itx;
        lr_rename_whiteout_t *lr;
        size_t snamesize = strlen(sname) + 1;
        size_t dnamesize = strlen(dname) + 1;

        if (zil_replaying(zilog, tx))
                return;

        txtype |= TX_RENAME_WHITEOUT;
        itx = zil_itx_create(txtype, sizeof (*lr) + snamesize + dnamesize);
        lr = (lr_rename_whiteout_t *)&itx->itx_lr;
        lr->lr_rename.lr_sdoid = sdzp->z_id;
        lr->lr_rename.lr_tdoid = tdzp->z_id;

        /*
         * RENAME_WHITEOUT will create an entry at the source znode, so we need
         * to store the same data that the equivalent call to zfs_log_create()
         * would.
         */
        lr->lr_wfoid = wzp->z_id;
        LR_FOID_SET_SLOTS(lr->lr_wfoid, wzp->z_dnodesize >> DNODE_SHIFT);
        (void) sa_lookup(wzp->z_sa_hdl, SA_ZPL_GEN(ZTOZSB(wzp)), &lr->lr_wgen,
            sizeof (uint64_t));
        (void) sa_lookup(wzp->z_sa_hdl, SA_ZPL_CRTIME(ZTOZSB(wzp)),
            lr->lr_wcrtime, sizeof (uint64_t) * 2);
        lr->lr_wmode = wzp->z_mode;
        lr->lr_wuid = (uint64_t)KUID_TO_SUID(ZTOUID(wzp));
        lr->lr_wgid = (uint64_t)KGID_TO_SGID(ZTOGID(wzp));

        /*
         * This rdev will always be makdevice(0, 0) but because the ZIL log and
         * replay code needs to be platform independent (and there is no
         * platform independent makdev()) we need to copy the one created
         * during the rename operation.
         */
        (void) sa_lookup(wzp->z_sa_hdl, SA_ZPL_RDEV(ZTOZSB(wzp)), &lr->lr_wrdev,
            sizeof (lr->lr_wrdev));

        memcpy((char *)(lr + 1), sname, snamesize);
        memcpy((char *)(lr + 1) + snamesize, dname, dnamesize);
        itx->itx_oid = szp->z_id;

        zil_itx_assign(zilog, itx, tx);
}

/*
 * zfs_log_write() handles TX_WRITE transactions. The specified callback is
 * called as soon as the write is on stable storage (be it via a DMU sync or a
 * ZIL commit).
 */
static int64_t zfs_immediate_write_sz = 32768;

void
zfs_log_write(zilog_t *zilog, dmu_tx_t *tx, int txtype,
    znode_t *zp, offset_t off, ssize_t resid, int ioflag,
    zil_callback_t callback, void *callback_data)
{
        dmu_buf_impl_t *db = (dmu_buf_impl_t *)sa_get_db(zp->z_sa_hdl);
        uint32_t blocksize = zp->z_blksz;
        itx_wr_state_t write_state;
        uintptr_t fsync_cnt;
        uint64_t gen = 0;
        ssize_t size = resid;

        if (zil_replaying(zilog, tx) || zp->z_unlinked ||
            zfs_xattr_owner_unlinked(zp)) {
                if (callback != NULL)
                        callback(callback_data);
                return;
        }

        if (zilog->zl_logbias == ZFS_LOGBIAS_THROUGHPUT)
                write_state = WR_INDIRECT;
        else if (!spa_has_slogs(zilog->zl_spa) &&
            resid >= zfs_immediate_write_sz)
                write_state = WR_INDIRECT;
        else if (ioflag & (O_SYNC | O_DSYNC))
                write_state = WR_COPIED;
        else
                write_state = WR_NEED_COPY;

        if ((fsync_cnt = (uintptr_t)tsd_get(zfs_fsyncer_key)) != 0) {
                (void) tsd_set(zfs_fsyncer_key, (void *)(fsync_cnt - 1));
        }

        (void) sa_lookup(zp->z_sa_hdl, SA_ZPL_GEN(ZTOZSB(zp)), &gen,
            sizeof (gen));

        while (resid) {
                itx_t *itx;
                lr_write_t *lr;
                itx_wr_state_t wr_state = write_state;
                ssize_t len = resid;

                /*
                 * A WR_COPIED record must fit entirely in one log block.
                 * Large writes can use WR_NEED_COPY, which the ZIL will
                 * split into multiple records across several log blocks
                 * if necessary.
                 */
                if (wr_state == WR_COPIED &&
                    resid > zil_max_copied_data(zilog))
                        wr_state = WR_NEED_COPY;
                else if (wr_state == WR_INDIRECT)
                        len = MIN(blocksize - P2PHASE(off, blocksize), resid);

                itx = zil_itx_create(txtype, sizeof (*lr) +
                    (wr_state == WR_COPIED ? len : 0));
                lr = (lr_write_t *)&itx->itx_lr;

                /*
                 * For WR_COPIED records, copy the data into the lr_write_t.
                 */
                if (wr_state == WR_COPIED) {
                        int err;
                        DB_DNODE_ENTER(db);
                        err = dmu_read_by_dnode(DB_DNODE(db), off, len, lr + 1,
                            DMU_READ_NO_PREFETCH);
                        if (err != 0) {
                                zil_itx_destroy(itx);
                                itx = zil_itx_create(txtype, sizeof (*lr));
                                lr = (lr_write_t *)&itx->itx_lr;
                                wr_state = WR_NEED_COPY;
                        }
                        DB_DNODE_EXIT(db);
                }

                itx->itx_wr_state = wr_state;
                lr->lr_foid = zp->z_id;
                lr->lr_offset = off;
                lr->lr_length = len;
                lr->lr_blkoff = 0;
                BP_ZERO(&lr->lr_blkptr);

                itx->itx_private = ZTOZSB(zp);
                itx->itx_gen = gen;

                if (!(ioflag & (O_SYNC | O_DSYNC)) && (zp->z_sync_cnt == 0) &&
                    (fsync_cnt == 0))
                        itx->itx_sync = B_FALSE;

                itx->itx_callback = callback;
                itx->itx_callback_data = callback_data;
                zil_itx_assign(zilog, itx, tx);

                off += len;
                resid -= len;
        }

        if (write_state == WR_COPIED || write_state == WR_NEED_COPY) {
                dsl_pool_wrlog_count(zilog->zl_dmu_pool, size, tx->tx_txg);
        }
}

/*
 * Handles TX_TRUNCATE transactions.
 */
void
zfs_log_truncate(zilog_t *zilog, dmu_tx_t *tx, int txtype,
    znode_t *zp, uint64_t off, uint64_t len)
{
        itx_t *itx;
        lr_truncate_t *lr;

        if (zil_replaying(zilog, tx) || zp->z_unlinked ||
            zfs_xattr_owner_unlinked(zp))
                return;

        itx = zil_itx_create(txtype, sizeof (*lr));
        lr = (lr_truncate_t *)&itx->itx_lr;
        lr->lr_foid = zp->z_id;
        lr->lr_offset = off;
        lr->lr_length = len;

        itx->itx_sync = (zp->z_sync_cnt != 0);
        zil_itx_assign(zilog, itx, tx);
}

/*
 * Handles TX_SETATTR transactions.
 */
void
zfs_log_setattr(zilog_t *zilog, dmu_tx_t *tx, int txtype,
    znode_t *zp, vattr_t *vap, uint_t mask_applied, zfs_fuid_info_t *fuidp)
{
        itx_t           *itx;
        lr_setattr_t    *lr;
        xvattr_t        *xvap = (xvattr_t *)vap;
        size_t          recsize = sizeof (lr_setattr_t);
        void            *start;

        if (zil_replaying(zilog, tx) || zp->z_unlinked)
                return;

        /*
         * If XVATTR set, then log record size needs to allow
         * for lr_attr_t + xvattr mask, mapsize and create time
         * plus actual attribute values
         */
        if (vap->va_mask & ATTR_XVATTR)
                recsize = sizeof (*lr) + ZIL_XVAT_SIZE(xvap->xva_mapsize);

        if (fuidp)
                recsize += fuidp->z_domain_str_sz;

        itx = zil_itx_create(txtype, recsize);
        lr = (lr_setattr_t *)&itx->itx_lr;
        lr->lr_foid = zp->z_id;
        lr->lr_mask = (uint64_t)mask_applied;
        lr->lr_mode = (uint64_t)vap->va_mode;
        if ((mask_applied & ATTR_UID) && IS_EPHEMERAL(vap->va_uid))
                lr->lr_uid = fuidp->z_fuid_owner;
        else
                lr->lr_uid = (uint64_t)vap->va_uid;

        if ((mask_applied & ATTR_GID) && IS_EPHEMERAL(vap->va_gid))
                lr->lr_gid = fuidp->z_fuid_group;
        else
                lr->lr_gid = (uint64_t)vap->va_gid;

        lr->lr_size = (uint64_t)vap->va_size;
        ZFS_TIME_ENCODE(&vap->va_atime, lr->lr_atime);
        ZFS_TIME_ENCODE(&vap->va_mtime, lr->lr_mtime);
        start = (lr_setattr_t *)(lr + 1);
        if (vap->va_mask & ATTR_XVATTR) {
                zfs_log_xvattr((lr_attr_t *)start, xvap);
                start = (caddr_t)start + ZIL_XVAT_SIZE(xvap->xva_mapsize);
        }

        /*
         * Now stick on domain information if any on end
         */

        if (fuidp)
                (void) zfs_log_fuid_domains(fuidp, start);

        itx->itx_sync = (zp->z_sync_cnt != 0);
        zil_itx_assign(zilog, itx, tx);
}

/*
 * Handles TX_SETSAXATTR transactions.
 */
void
zfs_log_setsaxattr(zilog_t *zilog, dmu_tx_t *tx, int txtype,
    znode_t *zp, const char *name, const void *value, size_t size)
{
        itx_t           *itx;
        lr_setsaxattr_t *lr;
        size_t          recsize = sizeof (lr_setsaxattr_t);
        void            *xattrstart;
        int             namelen;

        if (zil_replaying(zilog, tx) || zp->z_unlinked)
                return;

        namelen = strlen(name) + 1;
        recsize += (namelen + size);
        itx = zil_itx_create(txtype, recsize);
        lr = (lr_setsaxattr_t *)&itx->itx_lr;
        lr->lr_foid = zp->z_id;
        xattrstart = (char *)(lr + 1);
        memcpy(xattrstart, name, namelen);
        if (value != NULL) {
                memcpy((char *)xattrstart + namelen, value, size);
                lr->lr_size = size;
        } else {
                lr->lr_size = 0;
        }

        itx->itx_sync = (zp->z_sync_cnt != 0);
        zil_itx_assign(zilog, itx, tx);
}

/*
 * Handles TX_ACL transactions.
 */
void
zfs_log_acl(zilog_t *zilog, dmu_tx_t *tx, znode_t *zp,
    vsecattr_t *vsecp, zfs_fuid_info_t *fuidp)
{
        itx_t *itx;
        lr_acl_v0_t *lrv0;
        lr_acl_t *lr;
        int txtype;
        int lrsize;
        size_t txsize;
        size_t aclbytes = vsecp->vsa_aclentsz;

        if (zil_replaying(zilog, tx) || zp->z_unlinked)
                return;

        txtype = (ZTOZSB(zp)->z_version < ZPL_VERSION_FUID) ?
            TX_ACL_V0 : TX_ACL;

        if (txtype == TX_ACL)
                lrsize = sizeof (*lr);
        else
                lrsize = sizeof (*lrv0);

        txsize = lrsize +
            ((txtype == TX_ACL) ? ZIL_ACE_LENGTH(aclbytes) : aclbytes) +
            (fuidp ? fuidp->z_domain_str_sz : 0) +
            sizeof (uint64_t) * (fuidp ? fuidp->z_fuid_cnt : 0);

        itx = zil_itx_create(txtype, txsize);

        lr = (lr_acl_t *)&itx->itx_lr;
        lr->lr_foid = zp->z_id;
        if (txtype == TX_ACL) {
                lr->lr_acl_bytes = aclbytes;
                lr->lr_domcnt = fuidp ? fuidp->z_domain_cnt : 0;
                lr->lr_fuidcnt = fuidp ? fuidp->z_fuid_cnt : 0;
                if (vsecp->vsa_mask & VSA_ACE_ACLFLAGS)
                        lr->lr_acl_flags = (uint64_t)vsecp->vsa_aclflags;
                else
                        lr->lr_acl_flags = 0;
        }
        lr->lr_aclcnt = (uint64_t)vsecp->vsa_aclcnt;

        if (txtype == TX_ACL_V0) {
                lrv0 = (lr_acl_v0_t *)lr;
                memcpy(lrv0 + 1, vsecp->vsa_aclentp, aclbytes);
        } else {
                void *start = (ace_t *)(lr + 1);

                memcpy(start, vsecp->vsa_aclentp, aclbytes);

                start = (caddr_t)start + ZIL_ACE_LENGTH(aclbytes);

                if (fuidp) {
                        start = zfs_log_fuid_ids(fuidp, start);
                        (void) zfs_log_fuid_domains(fuidp, start);
                }
        }

        itx->itx_sync = (zp->z_sync_cnt != 0);
        zil_itx_assign(zilog, itx, tx);
}

ZFS_MODULE_PARAM(zfs, zfs_, immediate_write_sz, S64, ZMOD_RW,
        "Largest data block to write to zil");