FreeBSD/Linux Kernel Cross Reference
sys/contrib/openzfs/lib/libzfs_core/libzfs_core.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) 2012, 2020 by Delphix. All rights reserved.
     * Copyright (c) 2013 Steven Hartland. All rights reserved.
     * Copyright 2017 RackTop Systems.
     * Copyright (c) 2017 Open-E, Inc. All Rights Reserved.
     * Copyright (c) 2019, 2020 by Christian Schwarz. All rights reserved.
     * Copyright (c) 2019 Datto Inc.
     */
    
    /*
     * LibZFS_Core (lzc) is intended to replace most functionality in libzfs.
     * It has the following characteristics:
     *
     *  - Thread Safe.  libzfs_core is accessible concurrently from multiple
     *  threads.  This is accomplished primarily by avoiding global data
     *  (e.g. caching).  Since it's thread-safe, there is no reason for a
     *  process to have multiple libzfs "instances".  Therefore, we store
     *  our few pieces of data (e.g. the file descriptor) in global
     *  variables.  The fd is reference-counted so that the libzfs_core
     *  library can be "initialized" multiple times (e.g. by different
     *  consumers within the same process).
     *
     *  - Committed Interface.  The libzfs_core interface will be committed,
     *  therefore consumers can compile against it and be confident that
     *  their code will continue to work on future releases of this code.
     *  Currently, the interface is Evolving (not Committed), but we intend
     *  to commit to it once it is more complete and we determine that it
     *  meets the needs of all consumers.
     *
     *  - Programmatic Error Handling.  libzfs_core communicates errors with
     *  defined error numbers, and doesn't print anything to stdout/stderr.
     *
     *  - Thin Layer.  libzfs_core is a thin layer, marshaling arguments
     *  to/from the kernel ioctls.  There is generally a 1:1 correspondence
     *  between libzfs_core functions and ioctls to ZFS_DEV.
     *
     *  - Clear Atomicity.  Because libzfs_core functions are generally 1:1
     *  with kernel ioctls, and kernel ioctls are general atomic, each
     *  libzfs_core function is atomic.  For example, creating multiple
     *  snapshots with a single call to lzc_snapshot() is atomic -- it
     *  can't fail with only some of the requested snapshots created, even
     *  in the event of power loss or system crash.
     *
     *  - Continued libzfs Support.  Some higher-level operations (e.g.
     *  support for "zfs send -R") are too complicated to fit the scope of
     *  libzfs_core.  This functionality will continue to live in libzfs.
     *  Where appropriate, libzfs will use the underlying atomic operations
     *  of libzfs_core.  For example, libzfs may implement "zfs send -R |
     *  zfs receive" by using individual "send one snapshot", rename,
     *  destroy, and "receive one snapshot" operations in libzfs_core.
     *  /sbin/zfs and /sbin/zpool will link with both libzfs and
     *  libzfs_core.  Other consumers should aim to use only libzfs_core,
     *  since that will be the supported, stable interface going forwards.
     */
    
    #include <libzfs_core.h>
    #include <ctype.h>
    #include <unistd.h>
    #include <stdlib.h>
    #include <string.h>
    #ifdef ZFS_DEBUG
    #include <stdio.h>
    #endif
    #include <errno.h>
    #include <fcntl.h>
    #include <pthread.h>
    #include <libzutil.h>
    #include <sys/nvpair.h>
    #include <sys/param.h>
    #include <sys/types.h>
    #include <sys/stat.h>
    #include <sys/zfs_ioctl.h>
    #if __FreeBSD__
    #define BIG_PIPE_SIZE (64 * 1024) /* From sys/pipe.h */
    #endif
    
    static int g_fd = -1;
    static pthread_mutex_t g_lock = PTHREAD_MUTEX_INITIALIZER;
   static int g_refcount;
   
   #ifdef ZFS_DEBUG
   static zfs_ioc_t fail_ioc_cmd = ZFS_IOC_LAST;
   static zfs_errno_t fail_ioc_err;
   
   static void
   libzfs_core_debug_ioc(void)
   {
           /*
            * To test running newer user space binaries with kernel's
            * that don't yet support an ioctl or a new ioctl arg we
            * provide an override to intentionally fail an ioctl.
            *
            * USAGE:
            * The override variable, ZFS_IOC_TEST, is of the form "cmd:err"
            *
            * For example, to fail a ZFS_IOC_POOL_CHECKPOINT with a
            * ZFS_ERR_IOC_CMD_UNAVAIL, the string would be "0x5a4d:1029"
            *
            * $ sudo sh -c "ZFS_IOC_TEST=0x5a4d:1029 zpool checkpoint tank"
            * cannot checkpoint 'tank': the loaded zfs module does not support
            * this operation. A reboot may be required to enable this operation.
            */
           if (fail_ioc_cmd == ZFS_IOC_LAST) {
                   char *ioc_test = getenv("ZFS_IOC_TEST");
                   unsigned int ioc_num = 0, ioc_err = 0;
   
                   if (ioc_test != NULL &&
                       sscanf(ioc_test, "%i:%i", &ioc_num, &ioc_err) == 2 &&
                       ioc_num < ZFS_IOC_LAST)  {
                           fail_ioc_cmd = ioc_num;
                           fail_ioc_err = ioc_err;
                   }
           }
   }
   #endif
   
   int
   libzfs_core_init(void)
   {
           (void) pthread_mutex_lock(&g_lock);
           if (g_refcount == 0) {
                   g_fd = open(ZFS_DEV, O_RDWR|O_CLOEXEC);
                   if (g_fd < 0) {
                           (void) pthread_mutex_unlock(&g_lock);
                           return (errno);
                   }
           }
           g_refcount++;
   
   #ifdef ZFS_DEBUG
           libzfs_core_debug_ioc();
   #endif
           (void) pthread_mutex_unlock(&g_lock);
           return (0);
   }
   
   void
   libzfs_core_fini(void)
   {
           (void) pthread_mutex_lock(&g_lock);
           ASSERT3S(g_refcount, >, 0);
   
           g_refcount--;
   
           if (g_refcount == 0 && g_fd != -1) {
                   (void) close(g_fd);
                   g_fd = -1;
           }
           (void) pthread_mutex_unlock(&g_lock);
   }
   
   static int
   lzc_ioctl(zfs_ioc_t ioc, const char *name,
       nvlist_t *source, nvlist_t **resultp)
   {
           zfs_cmd_t zc = {"\0"};
           int error = 0;
           char *packed = NULL;
           size_t size = 0;
   
           ASSERT3S(g_refcount, >, 0);
           VERIFY3S(g_fd, !=, -1);
   
   #ifdef ZFS_DEBUG
           if (ioc == fail_ioc_cmd)
                   return (fail_ioc_err);
   #endif
   
           if (name != NULL)
                   (void) strlcpy(zc.zc_name, name, sizeof (zc.zc_name));
   
           if (source != NULL) {
                   packed = fnvlist_pack(source, &size);
                   zc.zc_nvlist_src = (uint64_t)(uintptr_t)packed;
                   zc.zc_nvlist_src_size = size;
           }
   
           if (resultp != NULL) {
                   *resultp = NULL;
                   if (ioc == ZFS_IOC_CHANNEL_PROGRAM) {
                           zc.zc_nvlist_dst_size = fnvlist_lookup_uint64(source,
                               ZCP_ARG_MEMLIMIT);
                   } else {
                           zc.zc_nvlist_dst_size = MAX(size * 2, 128 * 1024);
                   }
                   zc.zc_nvlist_dst = (uint64_t)(uintptr_t)
                       malloc(zc.zc_nvlist_dst_size);
                   if (zc.zc_nvlist_dst == (uint64_t)0) {
                           error = ENOMEM;
                           goto out;
                   }
           }
   
           while (lzc_ioctl_fd(g_fd, ioc, &zc) != 0) {
                   /*
                    * If ioctl exited with ENOMEM, we retry the ioctl after
                    * increasing the size of the destination nvlist.
                    *
                    * Channel programs that exit with ENOMEM ran over the
                    * lua memory sandbox; they should not be retried.
                    */
                   if (errno == ENOMEM && resultp != NULL &&
                       ioc != ZFS_IOC_CHANNEL_PROGRAM) {
                           free((void *)(uintptr_t)zc.zc_nvlist_dst);
                           zc.zc_nvlist_dst_size *= 2;
                           zc.zc_nvlist_dst = (uint64_t)(uintptr_t)
                               malloc(zc.zc_nvlist_dst_size);
                           if (zc.zc_nvlist_dst == (uint64_t)0) {
                                   error = ENOMEM;
                                   goto out;
                           }
                   } else {
                           error = errno;
                           break;
                   }
           }
           if (zc.zc_nvlist_dst_filled && resultp != NULL) {
                   *resultp = fnvlist_unpack((void *)(uintptr_t)zc.zc_nvlist_dst,
                       zc.zc_nvlist_dst_size);
           }
   
   out:
           if (packed != NULL)
                   fnvlist_pack_free(packed, size);
           free((void *)(uintptr_t)zc.zc_nvlist_dst);
           return (error);
   }
   
   int
   lzc_create(const char *fsname, enum lzc_dataset_type type, nvlist_t *props,
       uint8_t *wkeydata, uint_t wkeylen)
   {
           int error;
           nvlist_t *hidden_args = NULL;
           nvlist_t *args = fnvlist_alloc();
   
           fnvlist_add_int32(args, "type", (dmu_objset_type_t)type);
           if (props != NULL)
                   fnvlist_add_nvlist(args, "props", props);
   
           if (wkeydata != NULL) {
                   hidden_args = fnvlist_alloc();
                   fnvlist_add_uint8_array(hidden_args, "wkeydata", wkeydata,
                       wkeylen);
                   fnvlist_add_nvlist(args, ZPOOL_HIDDEN_ARGS, hidden_args);
           }
   
           error = lzc_ioctl(ZFS_IOC_CREATE, fsname, args, NULL);
           nvlist_free(hidden_args);
           nvlist_free(args);
           return (error);
   }
   
   int
   lzc_clone(const char *fsname, const char *origin, nvlist_t *props)
   {
           int error;
           nvlist_t *hidden_args = NULL;
           nvlist_t *args = fnvlist_alloc();
   
           fnvlist_add_string(args, "origin", origin);
           if (props != NULL)
                   fnvlist_add_nvlist(args, "props", props);
           error = lzc_ioctl(ZFS_IOC_CLONE, fsname, args, NULL);
           nvlist_free(hidden_args);
           nvlist_free(args);
           return (error);
   }
   
   int
   lzc_promote(const char *fsname, char *snapnamebuf, int snapnamelen)
   {
           /*
            * The promote ioctl is still legacy, so we need to construct our
            * own zfs_cmd_t rather than using lzc_ioctl().
            */
           zfs_cmd_t zc = {"\0"};
   
           ASSERT3S(g_refcount, >, 0);
           VERIFY3S(g_fd, !=, -1);
   
           (void) strlcpy(zc.zc_name, fsname, sizeof (zc.zc_name));
           if (lzc_ioctl_fd(g_fd, ZFS_IOC_PROMOTE, &zc) != 0) {
                   int error = errno;
                   if (error == EEXIST && snapnamebuf != NULL)
                           (void) strlcpy(snapnamebuf, zc.zc_string, snapnamelen);
                   return (error);
           }
           return (0);
   }
   
   int
   lzc_rename(const char *source, const char *target)
   {
           zfs_cmd_t zc = {"\0"};
           int error;
   
           ASSERT3S(g_refcount, >, 0);
           VERIFY3S(g_fd, !=, -1);
           (void) strlcpy(zc.zc_name, source, sizeof (zc.zc_name));
           (void) strlcpy(zc.zc_value, target, sizeof (zc.zc_value));
           error = lzc_ioctl_fd(g_fd, ZFS_IOC_RENAME, &zc);
           if (error != 0)
                   error = errno;
           return (error);
   }
   
   int
   lzc_destroy(const char *fsname)
   {
           int error;
           nvlist_t *args = fnvlist_alloc();
           error = lzc_ioctl(ZFS_IOC_DESTROY, fsname, args, NULL);
           nvlist_free(args);
           return (error);
   }
   
   /*
    * Creates snapshots.
    *
    * The keys in the snaps nvlist are the snapshots to be created.
    * They must all be in the same pool.
    *
    * The props nvlist is properties to set.  Currently only user properties
    * are supported.  { user:prop_name -> string value }
    *
    * The returned results nvlist will have an entry for each snapshot that failed.
    * The value will be the (int32) error code.
    *
    * The return value will be 0 if all snapshots were created, otherwise it will
    * be the errno of a (unspecified) snapshot that failed.
    */
   int
   lzc_snapshot(nvlist_t *snaps, nvlist_t *props, nvlist_t **errlist)
   {
           nvpair_t *elem;
           nvlist_t *args;
           int error;
           char pool[ZFS_MAX_DATASET_NAME_LEN];
   
           *errlist = NULL;
   
           /* determine the pool name */
           elem = nvlist_next_nvpair(snaps, NULL);
           if (elem == NULL)
                   return (0);
           (void) strlcpy(pool, nvpair_name(elem), sizeof (pool));
           pool[strcspn(pool, "/@")] = '\0';
   
           args = fnvlist_alloc();
           fnvlist_add_nvlist(args, "snaps", snaps);
           if (props != NULL)
                   fnvlist_add_nvlist(args, "props", props);
   
           error = lzc_ioctl(ZFS_IOC_SNAPSHOT, pool, args, errlist);
           nvlist_free(args);
   
           return (error);
   }
   
   /*
    * Destroys snapshots.
    *
    * The keys in the snaps nvlist are the snapshots to be destroyed.
    * They must all be in the same pool.
    *
    * Snapshots that do not exist will be silently ignored.
    *
    * If 'defer' is not set, and a snapshot has user holds or clones, the
    * destroy operation will fail and none of the snapshots will be
    * destroyed.
    *
    * If 'defer' is set, and a snapshot has user holds or clones, it will be
    * marked for deferred destruction, and will be destroyed when the last hold
    * or clone is removed/destroyed.
    *
    * The return value will be 0 if all snapshots were destroyed (or marked for
    * later destruction if 'defer' is set) or didn't exist to begin with.
    *
    * Otherwise the return value will be the errno of a (unspecified) snapshot
    * that failed, no snapshots will be destroyed, and the errlist will have an
    * entry for each snapshot that failed.  The value in the errlist will be
    * the (int32) error code.
    */
   int
   lzc_destroy_snaps(nvlist_t *snaps, boolean_t defer, nvlist_t **errlist)
   {
           nvpair_t *elem;
           nvlist_t *args;
           int error;
           char pool[ZFS_MAX_DATASET_NAME_LEN];
   
           /* determine the pool name */
           elem = nvlist_next_nvpair(snaps, NULL);
           if (elem == NULL)
                   return (0);
           (void) strlcpy(pool, nvpair_name(elem), sizeof (pool));
           pool[strcspn(pool, "/@")] = '\0';
   
           args = fnvlist_alloc();
           fnvlist_add_nvlist(args, "snaps", snaps);
           if (defer)
                   fnvlist_add_boolean(args, "defer");
   
           error = lzc_ioctl(ZFS_IOC_DESTROY_SNAPS, pool, args, errlist);
           nvlist_free(args);
   
           return (error);
   }
   
   int
   lzc_snaprange_space(const char *firstsnap, const char *lastsnap,
       uint64_t *usedp)
   {
           nvlist_t *args;
           nvlist_t *result;
           int err;
           char fs[ZFS_MAX_DATASET_NAME_LEN];
           char *atp;
   
           /* determine the fs name */
           (void) strlcpy(fs, firstsnap, sizeof (fs));
           atp = strchr(fs, '@');
           if (atp == NULL)
                   return (EINVAL);
           *atp = '\0';
   
           args = fnvlist_alloc();
           fnvlist_add_string(args, "firstsnap", firstsnap);
   
           err = lzc_ioctl(ZFS_IOC_SPACE_SNAPS, lastsnap, args, &result);
           nvlist_free(args);
           if (err == 0)
                   *usedp = fnvlist_lookup_uint64(result, "used");
           fnvlist_free(result);
   
           return (err);
   }
   
   boolean_t
   lzc_exists(const char *dataset)
   {
           /*
            * The objset_stats ioctl is still legacy, so we need to construct our
            * own zfs_cmd_t rather than using lzc_ioctl().
            */
           zfs_cmd_t zc = {"\0"};
   
           ASSERT3S(g_refcount, >, 0);
           VERIFY3S(g_fd, !=, -1);
   
           (void) strlcpy(zc.zc_name, dataset, sizeof (zc.zc_name));
           return (lzc_ioctl_fd(g_fd, ZFS_IOC_OBJSET_STATS, &zc) == 0);
   }
   
   /*
    * outnvl is unused.
    * It was added to preserve the function signature in case it is
    * needed in the future.
    */
   int
   lzc_sync(const char *pool_name, nvlist_t *innvl, nvlist_t **outnvl)
   {
           (void) outnvl;
           return (lzc_ioctl(ZFS_IOC_POOL_SYNC, pool_name, innvl, NULL));
   }
   
   /*
    * Create "user holds" on snapshots.  If there is a hold on a snapshot,
    * the snapshot can not be destroyed.  (However, it can be marked for deletion
    * by lzc_destroy_snaps(defer=B_TRUE).)
    *
    * The keys in the nvlist are snapshot names.
    * The snapshots must all be in the same pool.
    * The value is the name of the hold (string type).
    *
    * If cleanup_fd is not -1, it must be the result of open(ZFS_DEV, O_EXCL).
    * In this case, when the cleanup_fd is closed (including on process
    * termination), the holds will be released.  If the system is shut down
    * uncleanly, the holds will be released when the pool is next opened
    * or imported.
    *
    * Holds for snapshots which don't exist will be skipped and have an entry
    * added to errlist, but will not cause an overall failure.
    *
    * The return value will be 0 if all holds, for snapshots that existed,
    * were successfully created.
    *
    * Otherwise the return value will be the errno of a (unspecified) hold that
    * failed and no holds will be created.
    *
    * In all cases the errlist will have an entry for each hold that failed
    * (name = snapshot), with its value being the error code (int32).
    */
   int
   lzc_hold(nvlist_t *holds, int cleanup_fd, nvlist_t **errlist)
   {
           char pool[ZFS_MAX_DATASET_NAME_LEN];
           nvlist_t *args;
           nvpair_t *elem;
           int error;
   
           /* determine the pool name */
           elem = nvlist_next_nvpair(holds, NULL);
           if (elem == NULL)
                   return (0);
           (void) strlcpy(pool, nvpair_name(elem), sizeof (pool));
           pool[strcspn(pool, "/@")] = '\0';
   
           args = fnvlist_alloc();
           fnvlist_add_nvlist(args, "holds", holds);
           if (cleanup_fd != -1)
                   fnvlist_add_int32(args, "cleanup_fd", cleanup_fd);
   
           error = lzc_ioctl(ZFS_IOC_HOLD, pool, args, errlist);
           nvlist_free(args);
           return (error);
   }
   
   /*
    * Release "user holds" on snapshots.  If the snapshot has been marked for
    * deferred destroy (by lzc_destroy_snaps(defer=B_TRUE)), it does not have
    * any clones, and all the user holds are removed, then the snapshot will be
    * destroyed.
    *
    * The keys in the nvlist are snapshot names.
    * The snapshots must all be in the same pool.
    * The value is an nvlist whose keys are the holds to remove.
    *
    * Holds which failed to release because they didn't exist will have an entry
    * added to errlist, but will not cause an overall failure.
    *
    * The return value will be 0 if the nvl holds was empty or all holds that
    * existed, were successfully removed.
    *
    * Otherwise the return value will be the errno of a (unspecified) hold that
    * failed to release and no holds will be released.
    *
    * In all cases the errlist will have an entry for each hold that failed to
    * to release.
    */
   int
   lzc_release(nvlist_t *holds, nvlist_t **errlist)
   {
           char pool[ZFS_MAX_DATASET_NAME_LEN];
           nvpair_t *elem;
   
           /* determine the pool name */
           elem = nvlist_next_nvpair(holds, NULL);
           if (elem == NULL)
                   return (0);
           (void) strlcpy(pool, nvpair_name(elem), sizeof (pool));
           pool[strcspn(pool, "/@")] = '\0';
   
           return (lzc_ioctl(ZFS_IOC_RELEASE, pool, holds, errlist));
   }
   
   /*
    * Retrieve list of user holds on the specified snapshot.
    *
    * On success, *holdsp will be set to an nvlist which the caller must free.
    * The keys are the names of the holds, and the value is the creation time
    * of the hold (uint64) in seconds since the epoch.
    */
   int
   lzc_get_holds(const char *snapname, nvlist_t **holdsp)
   {
           return (lzc_ioctl(ZFS_IOC_GET_HOLDS, snapname, NULL, holdsp));
   }
   
   static unsigned int
   max_pipe_buffer(int infd)
   {
   #if __linux__
           static unsigned int max;
           if (max == 0) {
                   max = 1048576; /* fs/pipe.c default */
   
                   FILE *procf = fopen("/proc/sys/fs/pipe-max-size", "re");
                   if (procf != NULL) {
                           if (fscanf(procf, "%u", &max) <= 0) {
                                   /* ignore error: max untouched if parse fails */
                           }
                           fclose(procf);
                   }
           }
   
           unsigned int cur = fcntl(infd, F_GETPIPE_SZ);
           /*
            * Sadly, Linux has an unfixed deadlock if you do SETPIPE_SZ on a pipe
            * with data in it.
            * cf. #13232, https://bugzilla.kernel.org/show_bug.cgi?id=212295
            *
            * And since the problem is in waking up the writer, there's nothing
            * we can do about it from here.
            *
            * So if people want to, they can set this, but they
            * may regret it...
            */
           if (getenv("ZFS_SET_PIPE_MAX") == NULL)
                   return (cur);
           if (cur < max && fcntl(infd, F_SETPIPE_SZ, max) != -1)
                   cur = max;
           return (cur);
   #else
           /* FreeBSD automatically resizes */
           (void) infd;
           return (BIG_PIPE_SIZE);
   #endif
   }
   
   #if __linux__
   struct send_worker_ctx {
           int from;       /* read end of pipe, with send data; closed on exit */
           int to;         /* original arbitrary output fd; mustn't be a pipe */
   };
   
   static void *
   send_worker(void *arg)
   {
           struct send_worker_ctx *ctx = arg;
           unsigned int bufsiz = max_pipe_buffer(ctx->from);
           ssize_t rd;
   
           while ((rd = splice(ctx->from, NULL, ctx->to, NULL, bufsiz,
               SPLICE_F_MOVE | SPLICE_F_MORE)) > 0)
                   ;
   
           int err = (rd == -1) ? errno : 0;
           close(ctx->from);
           return ((void *)(uintptr_t)err);
   }
   #endif
   
   /*
    * Since Linux 5.10, 4d03e3cc59828c82ee89ea6e27a2f3cdf95aaadf
    * ("fs: don't allow kernel reads and writes without iter ops"),
    * ZFS_IOC_SEND* will EINVAL when writing to /dev/null, /dev/zero, &c.
    *
    * This wrapper transparently executes func() with a pipe
    * by spawning a thread to copy from that pipe to the original output
    * in the background.
    *
    * Returns the error from func(), if nonzero,
    * otherwise the error from the thread.
    *
    * No-op if orig_fd is -1, already a pipe (but the buffer size is bumped),
    * and on not-Linux; as such, it is safe to wrap/call wrapped functions
    * in a wrapped context.
    */
   int
   lzc_send_wrapper(int (*func)(int, void *), int orig_fd, void *data)
   {
   #if __linux__
           struct stat sb;
           if (orig_fd != -1 && fstat(orig_fd, &sb) == -1)
                   return (errno);
           if (orig_fd == -1 || S_ISFIFO(sb.st_mode)) {
                   if (orig_fd != -1)
                           (void) max_pipe_buffer(orig_fd);
                   return (func(orig_fd, data));
           }
           if ((fcntl(orig_fd, F_GETFL) & O_ACCMODE) == O_RDONLY)
                   return (errno = EBADF);
   
           int rw[2];
           if (pipe2(rw, O_CLOEXEC) == -1)
                   return (errno);
   
           int err;
           pthread_t send_thread;
           struct send_worker_ctx ctx = {.from = rw[0], .to = orig_fd};
           if ((err = pthread_create(&send_thread, NULL, send_worker, &ctx))
               != 0) {
                   close(rw[0]);
                   close(rw[1]);
                   return (errno = err);
           }
   
           err = func(rw[1], data);
   
           void *send_err;
           close(rw[1]);
           pthread_join(send_thread, &send_err);
           if (err == 0 && send_err != 0)
                   errno = err = (uintptr_t)send_err;
   
           return (err);
   #else
           return (func(orig_fd, data));
   #endif
   }
   
   /*
    * Generate a zfs send stream for the specified snapshot and write it to
    * the specified file descriptor.
    *
    * "snapname" is the full name of the snapshot to send (e.g. "pool/fs@snap")
    *
    * If "from" is NULL, a full (non-incremental) stream will be sent.
    * If "from" is non-NULL, it must be the full name of a snapshot or
    * bookmark to send an incremental from (e.g. "pool/fs@earlier_snap" or
    * "pool/fs#earlier_bmark").  If non-NULL, the specified snapshot or
    * bookmark must represent an earlier point in the history of "snapname").
    * It can be an earlier snapshot in the same filesystem or zvol as "snapname",
    * or it can be the origin of "snapname"'s filesystem, or an earlier
    * snapshot in the origin, etc.
    *
    * "fd" is the file descriptor to write the send stream to.
    *
    * If "flags" contains LZC_SEND_FLAG_LARGE_BLOCK, the stream is permitted
    * to contain DRR_WRITE records with drr_length > 128K, and DRR_OBJECT
    * records with drr_blksz > 128K.
    *
    * If "flags" contains LZC_SEND_FLAG_EMBED_DATA, the stream is permitted
    * to contain DRR_WRITE_EMBEDDED records with drr_etype==BP_EMBEDDED_TYPE_DATA,
    * which the receiving system must support (as indicated by support
    * for the "embedded_data" feature).
    *
    * If "flags" contains LZC_SEND_FLAG_COMPRESS, the stream is generated by using
    * compressed WRITE records for blocks which are compressed on disk and in
    * memory.  If the lz4_compress feature is active on the sending system, then
    * the receiving system must have that feature enabled as well.
    *
    * If "flags" contains LZC_SEND_FLAG_RAW, the stream is generated, for encrypted
    * datasets, by sending data exactly as it exists on disk.  This allows backups
    * to be taken even if encryption keys are not currently loaded.
    */
   int
   lzc_send(const char *snapname, const char *from, int fd,
       enum lzc_send_flags flags)
   {
           return (lzc_send_resume_redacted(snapname, from, fd, flags, 0, 0,
               NULL));
   }
   
   int
   lzc_send_redacted(const char *snapname, const char *from, int fd,
       enum lzc_send_flags flags, const char *redactbook)
   {
           return (lzc_send_resume_redacted(snapname, from, fd, flags, 0, 0,
               redactbook));
   }
   
   int
   lzc_send_resume(const char *snapname, const char *from, int fd,
       enum lzc_send_flags flags, uint64_t resumeobj, uint64_t resumeoff)
   {
           return (lzc_send_resume_redacted(snapname, from, fd, flags, resumeobj,
               resumeoff, NULL));
   }
   
   /*
    * snapname: The name of the "tosnap", or the snapshot whose contents we are
    * sending.
    * from: The name of the "fromsnap", or the incremental source.
    * fd: File descriptor to write the stream to.
    * flags: flags that determine features to be used by the stream.
    * resumeobj: Object to resume from, for resuming send
    * resumeoff: Offset to resume from, for resuming send.
    * redactnv: nvlist of string -> boolean(ignored) containing the names of all
    * the snapshots that we should redact with respect to.
    * redactbook: Name of the redaction bookmark to create.
    *
    * Pre-wrapped.
    */
   static int
   lzc_send_resume_redacted_cb_impl(const char *snapname, const char *from, int fd,
       enum lzc_send_flags flags, uint64_t resumeobj, uint64_t resumeoff,
       const char *redactbook)
   {
           nvlist_t *args;
           int err;
   
           args = fnvlist_alloc();
           fnvlist_add_int32(args, "fd", fd);
           if (from != NULL)
                   fnvlist_add_string(args, "fromsnap", from);
           if (flags & LZC_SEND_FLAG_LARGE_BLOCK)
                   fnvlist_add_boolean(args, "largeblockok");
           if (flags & LZC_SEND_FLAG_EMBED_DATA)
                   fnvlist_add_boolean(args, "embedok");
           if (flags & LZC_SEND_FLAG_COMPRESS)
                   fnvlist_add_boolean(args, "compressok");
           if (flags & LZC_SEND_FLAG_RAW)
                   fnvlist_add_boolean(args, "rawok");
           if (flags & LZC_SEND_FLAG_SAVED)
                   fnvlist_add_boolean(args, "savedok");
           if (resumeobj != 0 || resumeoff != 0) {
                   fnvlist_add_uint64(args, "resume_object", resumeobj);
                   fnvlist_add_uint64(args, "resume_offset", resumeoff);
           }
           if (redactbook != NULL)
                   fnvlist_add_string(args, "redactbook", redactbook);
   
           err = lzc_ioctl(ZFS_IOC_SEND_NEW, snapname, args, NULL);
           nvlist_free(args);
           return (err);
   }
   
   struct lzc_send_resume_redacted {
           const char *snapname;
           const char *from;
           enum lzc_send_flags flags;
           uint64_t resumeobj;
           uint64_t resumeoff;
           const char *redactbook;
   };
   
   static int
   lzc_send_resume_redacted_cb(int fd, void *arg)
   {
           struct lzc_send_resume_redacted *zsrr = arg;
           return (lzc_send_resume_redacted_cb_impl(zsrr->snapname, zsrr->from,
               fd, zsrr->flags, zsrr->resumeobj, zsrr->resumeoff,
               zsrr->redactbook));
   }
   
   int
   lzc_send_resume_redacted(const char *snapname, const char *from, int fd,
       enum lzc_send_flags flags, uint64_t resumeobj, uint64_t resumeoff,
       const char *redactbook)
   {
           struct lzc_send_resume_redacted zsrr = {
                   .snapname = snapname,
                   .from = from,
                   .flags = flags,
                   .resumeobj = resumeobj,
                   .resumeoff = resumeoff,
                   .redactbook = redactbook,
           };
           return (lzc_send_wrapper(lzc_send_resume_redacted_cb, fd, &zsrr));
   }
   
   /*
    * "from" can be NULL, a snapshot, or a bookmark.
    *
    * If from is NULL, a full (non-incremental) stream will be estimated.  This
    * is calculated very efficiently.
    *
    * If from is a snapshot, lzc_send_space uses the deadlists attached to
    * each snapshot to efficiently estimate the stream size.
    *
    * If from is a bookmark, the indirect blocks in the destination snapshot
    * are traversed, looking for blocks with a birth time since the creation TXG of
    * the snapshot this bookmark was created from.  This will result in
    * significantly more I/O and be less efficient than a send space estimation on
    * an equivalent snapshot. This process is also used if redact_snaps is
    * non-null.
    *
    * Pre-wrapped.
    */
   static int
   lzc_send_space_resume_redacted_cb_impl(const char *snapname, const char *from,
       enum lzc_send_flags flags, uint64_t resumeobj, uint64_t resumeoff,
       uint64_t resume_bytes, const char *redactbook, int fd, uint64_t *spacep)
   {
           nvlist_t *args;
           nvlist_t *result;
           int err;
   
           args = fnvlist_alloc();
           if (from != NULL)
                   fnvlist_add_string(args, "from", from);
           if (flags & LZC_SEND_FLAG_LARGE_BLOCK)
                   fnvlist_add_boolean(args, "largeblockok");
           if (flags & LZC_SEND_FLAG_EMBED_DATA)
                   fnvlist_add_boolean(args, "embedok");
           if (flags & LZC_SEND_FLAG_COMPRESS)
                   fnvlist_add_boolean(args, "compressok");
           if (flags & LZC_SEND_FLAG_RAW)
                   fnvlist_add_boolean(args, "rawok");
           if (resumeobj != 0 || resumeoff != 0) {
                   fnvlist_add_uint64(args, "resume_object", resumeobj);
                   fnvlist_add_uint64(args, "resume_offset", resumeoff);
                   fnvlist_add_uint64(args, "bytes", resume_bytes);
           }
           if (redactbook != NULL)
                   fnvlist_add_string(args, "redactbook", redactbook);
           if (fd != -1)
                   fnvlist_add_int32(args, "fd", fd);
   
           err = lzc_ioctl(ZFS_IOC_SEND_SPACE, snapname, args, &result);
           nvlist_free(args);
           if (err == 0)
                   *spacep = fnvlist_lookup_uint64(result, "space");
           nvlist_free(result);
           return (err);
   }
   
   struct lzc_send_space_resume_redacted {
           const char *snapname;
           const char *from;
           enum lzc_send_flags flags;
           uint64_t resumeobj;
           uint64_t resumeoff;
           uint64_t resume_bytes;
           const char *redactbook;
           uint64_t *spacep;
   };
   
   static int
   lzc_send_space_resume_redacted_cb(int fd, void *arg)
   {
           struct lzc_send_space_resume_redacted *zssrr = arg;
           return (lzc_send_space_resume_redacted_cb_impl(zssrr->snapname,
               zssrr->from, zssrr->flags, zssrr->resumeobj, zssrr->resumeoff,
               zssrr->resume_bytes, zssrr->redactbook, fd, zssrr->spacep));
   }
   
   int
   lzc_send_space_resume_redacted(const char *snapname, const char *from,
       enum lzc_send_flags flags, uint64_t resumeobj, uint64_t resumeoff,
       uint64_t resume_bytes, const char *redactbook, int fd, uint64_t *spacep)
   {
           struct lzc_send_space_resume_redacted zssrr = {
                   .snapname = snapname,
                   .from = from,
                   .flags = flags,
                   .resumeobj = resumeobj,
                   .resumeoff = resumeoff,
                   .resume_bytes = resume_bytes,
                   .redactbook = redactbook,
                   .spacep = spacep,
           };
           return (lzc_send_wrapper(lzc_send_space_resume_redacted_cb,
               fd, &zssrr));
   }
   
   int
   lzc_send_space(const char *snapname, const char *from,
       enum lzc_send_flags flags, uint64_t *spacep)
   {
           return (lzc_send_space_resume_redacted(snapname, from, flags, 0, 0, 0,
               NULL, -1, spacep));
   }
   
   static int
   recv_read(int fd, void *buf, int ilen)
   {
           char *cp = buf;
           int rv;
           int len = ilen;
   
           do {
                   rv = read(fd, cp, len);
                   cp += rv;
                   len -= rv;
           } while (rv > 0);
   
           if (rv < 0 || len != 0)
                   return (EIO);
   
           return (0);
   }
   
   /*
    * Linux adds ZFS_IOC_RECV_NEW for resumable and raw streams and preserves the
    * legacy ZFS_IOC_RECV user/kernel interface.  The new interface supports all
    * stream options but is currently only used for resumable streams.  This way
    * updated user space utilities will interoperate with older kernel modules.
    *
    * Non-Linux OpenZFS platforms have opted to modify the legacy interface.
    */
   static int
   recv_impl(const char *snapname, nvlist_t *recvdprops, nvlist_t *localprops,
       uint8_t *wkeydata, uint_t wkeylen, const char *origin, boolean_t force,
       boolean_t heal, boolean_t resumable, boolean_t raw, int input_fd,
       const dmu_replay_record_t *begin_record, uint64_t *read_bytes,
       uint64_t *errflags, nvlist_t **errors)
   {
           dmu_replay_record_t drr;
           char fsname[MAXPATHLEN];
           char *atp;
           int error;
           boolean_t payload = B_FALSE;
   
           ASSERT3S(g_refcount, >, 0);
          VERIFY3S(g_fd, !=, -1);
  
          /* Set 'fsname' to the name of containing filesystem */
          (void) strlcpy(fsname, snapname, sizeof (fsname));
          atp = strchr(fsname, '@');
          if (atp == NULL)
                  return (EINVAL);
          *atp = '\0';
  
          /* If the fs does not exist, try its parent. */
          if (!lzc_exists(fsname)) {
                  char *slashp = strrchr(fsname, '/');
                  if (slashp == NULL)
                          return (ENOENT);
                  *slashp = '\0';
          }
  
          /*
           * It is not uncommon for gigabytes to be processed by zfs receive.
           * Speculatively increase the buffer size if supported by the platform.
           */
          struct stat sb;
          if (fstat(input_fd, &sb) == -1)
                  return (errno);
          if (S_ISFIFO(sb.st_mode))
                  (void) max_pipe_buffer(input_fd);
  
          /*
           * The begin_record is normally a non-byteswapped BEGIN record.
           * For resumable streams it may be set to any non-byteswapped
           * dmu_replay_record_t.
           */
          if (begin_record == NULL) {
                  error = recv_read(input_fd, &drr, sizeof (drr));
                  if (error != 0)
                          return (error);
          } else {
                  drr = *begin_record;
                  payload = (begin_record->drr_payloadlen != 0);
          }
  
          /*
           * All receives with a payload should use the new interface.
           */
          if (resumable || heal || raw || wkeydata != NULL || payload) {
                  nvlist_t *outnvl = NULL;
                  nvlist_t *innvl = fnvlist_alloc();
  
                  fnvlist_add_string(innvl, "snapname", snapname);
  
                  if (recvdprops != NULL)
                          fnvlist_add_nvlist(innvl, "props", recvdprops);
  
                  if (localprops != NULL)
                          fnvlist_add_nvlist(innvl, "localprops", localprops);
  
                  if (wkeydata != NULL) {
                          /*
                           * wkeydata must be placed in the special
                           * ZPOOL_HIDDEN_ARGS nvlist so that it
                           * will not be printed to the zpool history.
                           */
                          nvlist_t *hidden_args = fnvlist_alloc();
                          fnvlist_add_uint8_array(hidden_args, "wkeydata",
                              wkeydata, wkeylen);
                          fnvlist_add_nvlist(innvl, ZPOOL_HIDDEN_ARGS,
                              hidden_args);
                          nvlist_free(hidden_args);
                  }
  
                  if (origin != NULL && strlen(origin))
                          fnvlist_add_string(innvl, "origin", origin);
  
                  fnvlist_add_byte_array(innvl, "begin_record",
                      (uchar_t *)&drr, sizeof (drr));
  
                  fnvlist_add_int32(innvl, "input_fd", input_fd);
  
                  if (force)
                          fnvlist_add_boolean(innvl, "force");
  
                  if (resumable)
                          fnvlist_add_boolean(innvl, "resumable");
  
                  if (heal)
                          fnvlist_add_boolean(innvl, "heal");
  
                  error = lzc_ioctl(ZFS_IOC_RECV_NEW, fsname, innvl, &outnvl);
  
                  if (error == 0 && read_bytes != NULL)
                          error = nvlist_lookup_uint64(outnvl, "read_bytes",
                              read_bytes);
  
                  if (error == 0 && errflags != NULL)
                          error = nvlist_lookup_uint64(outnvl, "error_flags",
                              errflags);
  
                  if (error == 0 && errors != NULL) {
                          nvlist_t *nvl;
                          error = nvlist_lookup_nvlist(outnvl, "errors", &nvl);
                          if (error == 0)
                                  *errors = fnvlist_dup(nvl);
                  }
  
                  fnvlist_free(innvl);
                  fnvlist_free(outnvl);
          } else {
                  zfs_cmd_t zc = {"\0"};
                  char *rp_packed = NULL;
                  char *lp_packed = NULL;
                  size_t size;
  
                  ASSERT3S(g_refcount, >, 0);
  
                  (void) strlcpy(zc.zc_name, fsname, sizeof (zc.zc_name));
                  (void) strlcpy(zc.zc_value, snapname, sizeof (zc.zc_value));
  
                  if (recvdprops != NULL) {
                          rp_packed = fnvlist_pack(recvdprops, &size);
                          zc.zc_nvlist_src = (uint64_t)(uintptr_t)rp_packed;
                          zc.zc_nvlist_src_size = size;
                  }
  
                  if (localprops != NULL) {
                          lp_packed = fnvlist_pack(localprops, &size);
                          zc.zc_nvlist_conf = (uint64_t)(uintptr_t)lp_packed;
                          zc.zc_nvlist_conf_size = size;
                  }
  
                  if (origin != NULL)
                          (void) strlcpy(zc.zc_string, origin,
                              sizeof (zc.zc_string));
  
                  ASSERT3S(drr.drr_type, ==, DRR_BEGIN);
                  zc.zc_begin_record = drr.drr_u.drr_begin;
                  zc.zc_guid = force;
                  zc.zc_cookie = input_fd;
                  zc.zc_cleanup_fd = -1;
                  zc.zc_action_handle = 0;
  
                  zc.zc_nvlist_dst_size = 128 * 1024;
                  zc.zc_nvlist_dst = (uint64_t)(uintptr_t)
                      malloc(zc.zc_nvlist_dst_size);
  
                  error = lzc_ioctl_fd(g_fd, ZFS_IOC_RECV, &zc);
                  if (error != 0) {
                          error = errno;
                  } else {
                          if (read_bytes != NULL)
                                  *read_bytes = zc.zc_cookie;
  
                          if (errflags != NULL)
                                  *errflags = zc.zc_obj;
  
                          if (errors != NULL)
                                  VERIFY0(nvlist_unpack(
                                      (void *)(uintptr_t)zc.zc_nvlist_dst,
                                      zc.zc_nvlist_dst_size, errors, KM_SLEEP));
                  }
  
                  if (rp_packed != NULL)
                          fnvlist_pack_free(rp_packed, size);
                  if (lp_packed != NULL)
                          fnvlist_pack_free(lp_packed, size);
                  free((void *)(uintptr_t)zc.zc_nvlist_dst);
          }
  
          return (error);
  }
  
  /*
   * The simplest receive case: receive from the specified fd, creating the
   * specified snapshot.  Apply the specified properties as "received" properties
   * (which can be overridden by locally-set properties).  If the stream is a
   * clone, its origin snapshot must be specified by 'origin'.  The 'force'
   * flag will cause the target filesystem to be rolled back or destroyed if
   * necessary to receive.
   *
   * Return 0 on success or an errno on failure.
   *
   * Note: this interface does not work on dedup'd streams
   * (those with DMU_BACKUP_FEATURE_DEDUP).
   */
  int
  lzc_receive(const char *snapname, nvlist_t *props, const char *origin,
      boolean_t force, boolean_t raw, int fd)
  {
          return (recv_impl(snapname, props, NULL, NULL, 0, origin, force,
              B_FALSE, B_FALSE, raw, fd, NULL, NULL, NULL, NULL));
  }
  
  /*
   * Like lzc_receive, but if the receive fails due to premature stream
   * termination, the intermediate state will be preserved on disk.  In this
   * case, ECKSUM will be returned.  The receive may subsequently be resumed
   * with a resuming send stream generated by lzc_send_resume().
   */
  int
  lzc_receive_resumable(const char *snapname, nvlist_t *props, const char *origin,
      boolean_t force, boolean_t raw, int fd)
  {
          return (recv_impl(snapname, props, NULL, NULL, 0, origin, force,
              B_FALSE, B_TRUE, raw, fd, NULL, NULL, NULL, NULL));
  }
  
  /*
   * Like lzc_receive, but allows the caller to read the begin record and then to
   * pass it in.  That could be useful if the caller wants to derive, for example,
   * the snapname or the origin parameters based on the information contained in
   * the begin record.
   * The begin record must be in its original form as read from the stream,
   * in other words, it should not be byteswapped.
   *
   * The 'resumable' parameter allows to obtain the same behavior as with
   * lzc_receive_resumable.
   */
  int
  lzc_receive_with_header(const char *snapname, nvlist_t *props,
      const char *origin, boolean_t force, boolean_t resumable, boolean_t raw,
      int fd, const dmu_replay_record_t *begin_record)
  {
          if (begin_record == NULL)
                  return (EINVAL);
  
          return (recv_impl(snapname, props, NULL, NULL, 0, origin, force,
              B_FALSE, resumable, raw, fd, begin_record, NULL, NULL, NULL));
  }
  
  /*
   * Like lzc_receive, but allows the caller to pass all supported arguments
   * and retrieve all values returned.  The only additional input parameter
   * is 'cleanup_fd' which is used to set a cleanup-on-exit file descriptor.
   *
   * The following parameters all provide return values.  Several may be set
   * in the failure case and will contain additional information.
   *
   * The 'read_bytes' value will be set to the total number of bytes read.
   *
   * The 'errflags' value will contain zprop_errflags_t flags which are
   * used to describe any failures.
   *
   * The 'action_handle' and 'cleanup_fd' are no longer used, and are ignored.
   *
   * The 'errors' nvlist contains an entry for each unapplied received
   * property.  Callers are responsible for freeing this nvlist.
   */
  int
  lzc_receive_one(const char *snapname, nvlist_t *props,
      const char *origin, boolean_t force, boolean_t resumable, boolean_t raw,
      int input_fd, const dmu_replay_record_t *begin_record, int cleanup_fd,
      uint64_t *read_bytes, uint64_t *errflags, uint64_t *action_handle,
      nvlist_t **errors)
  {
          (void) action_handle, (void) cleanup_fd;
          return (recv_impl(snapname, props, NULL, NULL, 0, origin, force,
              B_FALSE, resumable, raw, input_fd, begin_record,
              read_bytes, errflags, errors));
  }
  
  /*
   * Like lzc_receive_one, but allows the caller to pass an additional 'cmdprops'
   * argument.
   *
   * The 'cmdprops' nvlist contains both override ('zfs receive -o') and
   * exclude ('zfs receive -x') properties. Callers are responsible for freeing
   * this nvlist
   */
  int
  lzc_receive_with_cmdprops(const char *snapname, nvlist_t *props,
      nvlist_t *cmdprops, uint8_t *wkeydata, uint_t wkeylen, const char *origin,
      boolean_t force, boolean_t resumable, boolean_t raw, int input_fd,
      const dmu_replay_record_t *begin_record, int cleanup_fd,
      uint64_t *read_bytes, uint64_t *errflags, uint64_t *action_handle,
      nvlist_t **errors)
  {
          (void) action_handle, (void) cleanup_fd;
          return (recv_impl(snapname, props, cmdprops, wkeydata, wkeylen, origin,
              force, B_FALSE, resumable, raw, input_fd, begin_record,
              read_bytes, errflags, errors));
  }
  
  /*
   * Like lzc_receive_with_cmdprops, but allows the caller to pass an additional
   * 'heal' argument.
   *
   * The heal arguments tells us to heal the provided snapshot using the provided
   * send stream
   */
  int lzc_receive_with_heal(const char *snapname, nvlist_t *props,
      nvlist_t *cmdprops, uint8_t *wkeydata, uint_t wkeylen, const char *origin,
      boolean_t force, boolean_t heal, boolean_t resumable, boolean_t raw,
      int input_fd, const dmu_replay_record_t *begin_record, int cleanup_fd,
      uint64_t *read_bytes, uint64_t *errflags, uint64_t *action_handle,
      nvlist_t **errors)
  {
          (void) action_handle, (void) cleanup_fd;
          return (recv_impl(snapname, props, cmdprops, wkeydata, wkeylen, origin,
              force, heal, resumable, raw, input_fd, begin_record,
              read_bytes, errflags, errors));
  }
  
  /*
   * Roll back this filesystem or volume to its most recent snapshot.
   * If snapnamebuf is not NULL, it will be filled in with the name
   * of the most recent snapshot.
   * Note that the latest snapshot may change if a new one is concurrently
   * created or the current one is destroyed.  lzc_rollback_to can be used
   * to roll back to a specific latest snapshot.
   *
   * Return 0 on success or an errno on failure.
   */
  int
  lzc_rollback(const char *fsname, char *snapnamebuf, int snapnamelen)
  {
          nvlist_t *args;
          nvlist_t *result;
          int err;
  
          args = fnvlist_alloc();
          err = lzc_ioctl(ZFS_IOC_ROLLBACK, fsname, args, &result);
          nvlist_free(args);
          if (err == 0 && snapnamebuf != NULL) {
                  const char *snapname = fnvlist_lookup_string(result, "target");
                  (void) strlcpy(snapnamebuf, snapname, snapnamelen);
          }
          nvlist_free(result);
  
          return (err);
  }
  
  /*
   * Roll back this filesystem or volume to the specified snapshot,
   * if possible.
   *
   * Return 0 on success or an errno on failure.
   */
  int
  lzc_rollback_to(const char *fsname, const char *snapname)
  {
          nvlist_t *args;
          nvlist_t *result;
          int err;
  
          args = fnvlist_alloc();
          fnvlist_add_string(args, "target", snapname);
          err = lzc_ioctl(ZFS_IOC_ROLLBACK, fsname, args, &result);
          nvlist_free(args);
          nvlist_free(result);
          return (err);
  }
  
  /*
   * Creates new bookmarks from existing snapshot or bookmark.
   *
   * The bookmarks nvlist maps from the full name of the new bookmark to
   * the full name of the source snapshot or bookmark.
   * All the bookmarks and snapshots must be in the same pool.
   * The new bookmarks names must be unique.
   * => see function dsl_bookmark_create_nvl_validate
   *
   * The returned results nvlist will have an entry for each bookmark that failed.
   * The value will be the (int32) error code.
   *
   * The return value will be 0 if all bookmarks were created, otherwise it will
   * be the errno of a (undetermined) bookmarks that failed.
   */
  int
  lzc_bookmark(nvlist_t *bookmarks, nvlist_t **errlist)
  {
          nvpair_t *elem;
          int error;
          char pool[ZFS_MAX_DATASET_NAME_LEN];
  
          /* determine pool name from first bookmark */
          elem = nvlist_next_nvpair(bookmarks, NULL);
          if (elem == NULL)
                  return (0);
          (void) strlcpy(pool, nvpair_name(elem), sizeof (pool));
          pool[strcspn(pool, "/#")] = '\0';
  
          error = lzc_ioctl(ZFS_IOC_BOOKMARK, pool, bookmarks, errlist);
  
          return (error);
  }
  
  /*
   * Retrieve bookmarks.
   *
   * Retrieve the list of bookmarks for the given file system. The props
   * parameter is an nvlist of property names (with no values) that will be
   * returned for each bookmark.
   *
   * The following are valid properties on bookmarks, most of which are numbers
   * (represented as uint64 in the nvlist), except redact_snaps, which is a
   * uint64 array, and redact_complete, which is a boolean
   *
   * "guid" - globally unique identifier of the snapshot it refers to
   * "createtxg" - txg when the snapshot it refers to was created
   * "creation" - timestamp when the snapshot it refers to was created
   * "ivsetguid" - IVset guid for identifying encrypted snapshots
   * "redact_snaps" - list of guids of the redaction snapshots for the specified
   *     bookmark.  If the bookmark is not a redaction bookmark, the nvlist will
   *     not contain an entry for this value.  If it is redacted with respect to
   *     no snapshots, it will contain value -> NULL uint64 array
   * "redact_complete" - boolean value; true if the redaction bookmark is
   *     complete, false otherwise.
   *
   * The format of the returned nvlist as follows:
   * <short name of bookmark> -> {
   *     <name of property> -> {
   *         "value" -> uint64
   *     }
   *     ...
   *     "redact_snaps" -> {
   *         "value" -> uint64 array
   *     }
   *     "redact_complete" -> {
   *         "value" -> boolean value
   *     }
   *  }
   */
  int
  lzc_get_bookmarks(const char *fsname, nvlist_t *props, nvlist_t **bmarks)
  {
          return (lzc_ioctl(ZFS_IOC_GET_BOOKMARKS, fsname, props, bmarks));
  }
  
  /*
   * Get bookmark properties.
   *
   * Given a bookmark's full name, retrieve all properties for the bookmark.
   *
   * The format of the returned property list is as follows:
   * {
   *     <name of property> -> {
   *         "value" -> uint64
   *     }
   *     ...
   *     "redact_snaps" -> {
   *         "value" -> uint64 array
   * }
   */
  int
  lzc_get_bookmark_props(const char *bookmark, nvlist_t **props)
  {
          int error;
  
          nvlist_t *innvl = fnvlist_alloc();
          error = lzc_ioctl(ZFS_IOC_GET_BOOKMARK_PROPS, bookmark, innvl, props);
          fnvlist_free(innvl);
  
          return (error);
  }
  
  /*
   * Destroys bookmarks.
   *
   * The keys in the bmarks nvlist are the bookmarks to be destroyed.
   * They must all be in the same pool.  Bookmarks are specified as
   * <fs>#<bmark>.
   *
   * Bookmarks that do not exist will be silently ignored.
   *
   * The return value will be 0 if all bookmarks that existed were destroyed.
   *
   * Otherwise the return value will be the errno of a (undetermined) bookmark
   * that failed, no bookmarks will be destroyed, and the errlist will have an
   * entry for each bookmarks that failed.  The value in the errlist will be
   * the (int32) error code.
   */
  int
  lzc_destroy_bookmarks(nvlist_t *bmarks, nvlist_t **errlist)
  {
          nvpair_t *elem;
          int error;
          char pool[ZFS_MAX_DATASET_NAME_LEN];
  
          /* determine the pool name */
          elem = nvlist_next_nvpair(bmarks, NULL);
          if (elem == NULL)
                  return (0);
          (void) strlcpy(pool, nvpair_name(elem), sizeof (pool));
          pool[strcspn(pool, "/#")] = '\0';
  
          error = lzc_ioctl(ZFS_IOC_DESTROY_BOOKMARKS, pool, bmarks, errlist);
  
          return (error);
  }
  
  static int
  lzc_channel_program_impl(const char *pool, const char *program, boolean_t sync,
      uint64_t instrlimit, uint64_t memlimit, nvlist_t *argnvl, nvlist_t **outnvl)
  {
          int error;
          nvlist_t *args;
  
          args = fnvlist_alloc();
          fnvlist_add_string(args, ZCP_ARG_PROGRAM, program);
          fnvlist_add_nvlist(args, ZCP_ARG_ARGLIST, argnvl);
          fnvlist_add_boolean_value(args, ZCP_ARG_SYNC, sync);
          fnvlist_add_uint64(args, ZCP_ARG_INSTRLIMIT, instrlimit);
          fnvlist_add_uint64(args, ZCP_ARG_MEMLIMIT, memlimit);
          error = lzc_ioctl(ZFS_IOC_CHANNEL_PROGRAM, pool, args, outnvl);
          fnvlist_free(args);
  
          return (error);
  }
  
  /*
   * Executes a channel program.
   *
   * If this function returns 0 the channel program was successfully loaded and
   * ran without failing. Note that individual commands the channel program ran
   * may have failed and the channel program is responsible for reporting such
   * errors through outnvl if they are important.
   *
   * This method may also return:
   *
   * EINVAL   The program contains syntax errors, or an invalid memory or time
   *          limit was given. No part of the channel program was executed.
   *          If caused by syntax errors, 'outnvl' contains information about the
   *          errors.
   *
   * ECHRNG   The program was executed, but encountered a runtime error, such as
   *          calling a function with incorrect arguments, invoking the error()
   *          function directly, failing an assert() command, etc. Some portion
   *          of the channel program may have executed and committed changes.
   *          Information about the failure can be found in 'outnvl'.
   *
   * ENOMEM   The program fully executed, but the output buffer was not large
   *          enough to store the returned value. No output is returned through
   *          'outnvl'.
   *
   * ENOSPC   The program was terminated because it exceeded its memory usage
   *          limit. Some portion of the channel program may have executed and
   *          committed changes to disk. No output is returned through 'outnvl'.
   *
   * ETIME    The program was terminated because it exceeded its Lua instruction
   *          limit. Some portion of the channel program may have executed and
   *          committed changes to disk. No output is returned through 'outnvl'.
   */
  int
  lzc_channel_program(const char *pool, const char *program, uint64_t instrlimit,
      uint64_t memlimit, nvlist_t *argnvl, nvlist_t **outnvl)
  {
          return (lzc_channel_program_impl(pool, program, B_TRUE, instrlimit,
              memlimit, argnvl, outnvl));
  }
  
  /*
   * Creates a checkpoint for the specified pool.
   *
   * If this function returns 0 the pool was successfully checkpointed.
   *
   * This method may also return:
   *
   * ZFS_ERR_CHECKPOINT_EXISTS
   *      The pool already has a checkpoint. A pools can only have one
   *      checkpoint at most, at any given time.
   *
   * ZFS_ERR_DISCARDING_CHECKPOINT
   *      ZFS is in the middle of discarding a checkpoint for this pool.
   *      The pool can be checkpointed again once the discard is done.
   *
   * ZFS_DEVRM_IN_PROGRESS
   *      A vdev is currently being removed. The pool cannot be
   *      checkpointed until the device removal is done.
   *
   * ZFS_VDEV_TOO_BIG
   *      One or more top-level vdevs exceed the maximum vdev size
   *      supported for this feature.
   */
  int
  lzc_pool_checkpoint(const char *pool)
  {
          int error;
  
          nvlist_t *result = NULL;
          nvlist_t *args = fnvlist_alloc();
  
          error = lzc_ioctl(ZFS_IOC_POOL_CHECKPOINT, pool, args, &result);
  
          fnvlist_free(args);
          fnvlist_free(result);
  
          return (error);
  }
  
  /*
   * Discard the checkpoint from the specified pool.
   *
   * If this function returns 0 the checkpoint was successfully discarded.
   *
   * This method may also return:
   *
   * ZFS_ERR_NO_CHECKPOINT
   *      The pool does not have a checkpoint.
   *
   * ZFS_ERR_DISCARDING_CHECKPOINT
   *      ZFS is already in the middle of discarding the checkpoint.
   */
  int
  lzc_pool_checkpoint_discard(const char *pool)
  {
          int error;
  
          nvlist_t *result = NULL;
          nvlist_t *args = fnvlist_alloc();
  
          error = lzc_ioctl(ZFS_IOC_POOL_DISCARD_CHECKPOINT, pool, args, &result);
  
          fnvlist_free(args);
          fnvlist_free(result);
  
          return (error);
  }
  
  /*
   * Executes a read-only channel program.
   *
   * A read-only channel program works programmatically the same way as a
   * normal channel program executed with lzc_channel_program(). The only
   * difference is it runs exclusively in open-context and therefore can
   * return faster. The downside to that, is that the program cannot change
   * on-disk state by calling functions from the zfs.sync submodule.
   *
   * The return values of this function (and their meaning) are exactly the
   * same as the ones described in lzc_channel_program().
   */
  int
  lzc_channel_program_nosync(const char *pool, const char *program,
      uint64_t timeout, uint64_t memlimit, nvlist_t *argnvl, nvlist_t **outnvl)
  {
          return (lzc_channel_program_impl(pool, program, B_FALSE, timeout,
              memlimit, argnvl, outnvl));
  }
  
  int
  lzc_get_vdev_prop(const char *poolname, nvlist_t *innvl, nvlist_t **outnvl)
  {
          return (lzc_ioctl(ZFS_IOC_VDEV_GET_PROPS, poolname, innvl, outnvl));
  }
  
  int
  lzc_set_vdev_prop(const char *poolname, nvlist_t *innvl, nvlist_t **outnvl)
  {
          return (lzc_ioctl(ZFS_IOC_VDEV_SET_PROPS, poolname, innvl, outnvl));
  }
  
  /*
   * Performs key management functions
   *
   * crypto_cmd should be a value from dcp_cmd_t. If the command specifies to
   * load or change a wrapping key, the key should be specified in the
   * hidden_args nvlist so that it is not logged.
   */
  int
  lzc_load_key(const char *fsname, boolean_t noop, uint8_t *wkeydata,
      uint_t wkeylen)
  {
          int error;
          nvlist_t *ioc_args;
          nvlist_t *hidden_args;
  
          if (wkeydata == NULL)
                  return (EINVAL);
  
          ioc_args = fnvlist_alloc();
          hidden_args = fnvlist_alloc();
          fnvlist_add_uint8_array(hidden_args, "wkeydata", wkeydata, wkeylen);
          fnvlist_add_nvlist(ioc_args, ZPOOL_HIDDEN_ARGS, hidden_args);
          if (noop)
                  fnvlist_add_boolean(ioc_args, "noop");
          error = lzc_ioctl(ZFS_IOC_LOAD_KEY, fsname, ioc_args, NULL);
          nvlist_free(hidden_args);
          nvlist_free(ioc_args);
  
          return (error);
  }
  
  int
  lzc_unload_key(const char *fsname)
  {
          return (lzc_ioctl(ZFS_IOC_UNLOAD_KEY, fsname, NULL, NULL));
  }
  
  int
  lzc_change_key(const char *fsname, uint64_t crypt_cmd, nvlist_t *props,
      uint8_t *wkeydata, uint_t wkeylen)
  {
          int error;
          nvlist_t *ioc_args = fnvlist_alloc();
          nvlist_t *hidden_args = NULL;
  
          fnvlist_add_uint64(ioc_args, "crypt_cmd", crypt_cmd);
  
          if (wkeydata != NULL) {
                  hidden_args = fnvlist_alloc();
                  fnvlist_add_uint8_array(hidden_args, "wkeydata", wkeydata,
                      wkeylen);
                  fnvlist_add_nvlist(ioc_args, ZPOOL_HIDDEN_ARGS, hidden_args);
          }
  
          if (props != NULL)
                  fnvlist_add_nvlist(ioc_args, "props", props);
  
          error = lzc_ioctl(ZFS_IOC_CHANGE_KEY, fsname, ioc_args, NULL);
          nvlist_free(hidden_args);
          nvlist_free(ioc_args);
  
          return (error);
  }
  
  int
  lzc_reopen(const char *pool_name, boolean_t scrub_restart)
  {
          nvlist_t *args = fnvlist_alloc();
          int error;
  
          fnvlist_add_boolean_value(args, "scrub_restart", scrub_restart);
  
          error = lzc_ioctl(ZFS_IOC_POOL_REOPEN, pool_name, args, NULL);
          nvlist_free(args);
          return (error);
  }
  
  /*
   * Changes initializing state.
   *
   * vdevs should be a list of (<key>, guid) where guid is a uint64 vdev GUID.
   * The key is ignored.
   *
   * If there are errors related to vdev arguments, per-vdev errors are returned
   * in an nvlist with the key "vdevs". Each error is a (guid, errno) pair where
   * guid is stringified with PRIu64, and errno is one of the following as
   * an int64_t:
   *      - ENODEV if the device was not found
   *      - EINVAL if the devices is not a leaf or is not concrete (e.g. missing)
   *      - EROFS if the device is not writeable
   *      - EBUSY start requested but the device is already being either
   *              initialized or trimmed
   *      - ESRCH cancel/suspend requested but device is not being initialized
   *
   * If the errlist is empty, then return value will be:
   *      - EINVAL if one or more arguments was invalid
   *      - Other spa_open failures
   *      - 0 if the operation succeeded
   */
  int
  lzc_initialize(const char *poolname, pool_initialize_func_t cmd_type,
      nvlist_t *vdevs, nvlist_t **errlist)
  {
          int error;
  
          nvlist_t *args = fnvlist_alloc();
          fnvlist_add_uint64(args, ZPOOL_INITIALIZE_COMMAND, (uint64_t)cmd_type);
          fnvlist_add_nvlist(args, ZPOOL_INITIALIZE_VDEVS, vdevs);
  
          error = lzc_ioctl(ZFS_IOC_POOL_INITIALIZE, poolname, args, errlist);
  
          fnvlist_free(args);
  
          return (error);
  }
  
  /*
   * Changes TRIM state.
   *
   * vdevs should be a list of (<key>, guid) where guid is a uint64 vdev GUID.
   * The key is ignored.
   *
   * If there are errors related to vdev arguments, per-vdev errors are returned
   * in an nvlist with the key "vdevs". Each error is a (guid, errno) pair where
   * guid is stringified with PRIu64, and errno is one of the following as
   * an int64_t:
   *      - ENODEV if the device was not found
   *      - EINVAL if the devices is not a leaf or is not concrete (e.g. missing)
   *      - EROFS if the device is not writeable
   *      - EBUSY start requested but the device is already being either trimmed
   *              or initialized
   *      - ESRCH cancel/suspend requested but device is not being initialized
   *      - EOPNOTSUPP if the device does not support TRIM (or secure TRIM)
   *
   * If the errlist is empty, then return value will be:
   *      - EINVAL if one or more arguments was invalid
   *      - Other spa_open failures
   *      - 0 if the operation succeeded
   */
  int
  lzc_trim(const char *poolname, pool_trim_func_t cmd_type, uint64_t rate,
      boolean_t secure, nvlist_t *vdevs, nvlist_t **errlist)
  {
          int error;
  
          nvlist_t *args = fnvlist_alloc();
          fnvlist_add_uint64(args, ZPOOL_TRIM_COMMAND, (uint64_t)cmd_type);
          fnvlist_add_nvlist(args, ZPOOL_TRIM_VDEVS, vdevs);
          fnvlist_add_uint64(args, ZPOOL_TRIM_RATE, rate);
          fnvlist_add_boolean_value(args, ZPOOL_TRIM_SECURE, secure);
  
          error = lzc_ioctl(ZFS_IOC_POOL_TRIM, poolname, args, errlist);
  
          fnvlist_free(args);
  
          return (error);
  }
  
  /*
   * Create a redaction bookmark named bookname by redacting snapshot with respect
   * to all the snapshots in snapnv.
   */
  int
  lzc_redact(const char *snapshot, const char *bookname, nvlist_t *snapnv)
  {
          nvlist_t *args = fnvlist_alloc();
          fnvlist_add_string(args, "bookname", bookname);
          fnvlist_add_nvlist(args, "snapnv", snapnv);
          int error = lzc_ioctl(ZFS_IOC_REDACT, snapshot, args, NULL);
          fnvlist_free(args);
          return (error);
  }
  
  static int
  wait_common(const char *pool, zpool_wait_activity_t activity, boolean_t use_tag,
      uint64_t tag, boolean_t *waited)
  {
          nvlist_t *args = fnvlist_alloc();
          nvlist_t *result = NULL;
  
          fnvlist_add_int32(args, ZPOOL_WAIT_ACTIVITY, activity);
          if (use_tag)
                  fnvlist_add_uint64(args, ZPOOL_WAIT_TAG, tag);
  
          int error = lzc_ioctl(ZFS_IOC_WAIT, pool, args, &result);
  
          if (error == 0 && waited != NULL)
                  *waited = fnvlist_lookup_boolean_value(result,
                      ZPOOL_WAIT_WAITED);
  
          fnvlist_free(args);
          fnvlist_free(result);
  
          return (error);
  }
  
  int
  lzc_wait(const char *pool, zpool_wait_activity_t activity, boolean_t *waited)
  {
          return (wait_common(pool, activity, B_FALSE, 0, waited));
  }
  
  int
  lzc_wait_tag(const char *pool, zpool_wait_activity_t activity, uint64_t tag,
      boolean_t *waited)
  {
          return (wait_common(pool, activity, B_TRUE, tag, waited));
  }
  
  int
  lzc_wait_fs(const char *fs, zfs_wait_activity_t activity, boolean_t *waited)
  {
          nvlist_t *args = fnvlist_alloc();
          nvlist_t *result = NULL;
  
          fnvlist_add_int32(args, ZFS_WAIT_ACTIVITY, activity);
  
          int error = lzc_ioctl(ZFS_IOC_WAIT_FS, fs, args, &result);
  
          if (error == 0 && waited != NULL)
                  *waited = fnvlist_lookup_boolean_value(result,
                      ZFS_WAIT_WAITED);
  
          fnvlist_free(args);
          fnvlist_free(result);
  
          return (error);
  }
  
  /*
   * Set the bootenv contents for the given pool.
   */
  int
  lzc_set_bootenv(const char *pool, const nvlist_t *env)
  {
          return (lzc_ioctl(ZFS_IOC_SET_BOOTENV, pool, (nvlist_t *)env, NULL));
  }
  
  /*
   * Get the contents of the bootenv of the given pool.
   */
  int
  lzc_get_bootenv(const char *pool, nvlist_t **outnvl)
  {
          return (lzc_ioctl(ZFS_IOC_GET_BOOTENV, pool, NULL, outnvl));
  }

Cache object: 26d612fe7ce8b8b2284adfca3a8aa7d6