8115 parallel zfs mount

*** 52,61 ****
--- 52,62 ----
  #include <stddef.h>
  #include <ucred.h>
  #include <idmap.h>
  #include <aclutils.h>
  #include <directory.h>
+ #include <time.h>
  
  #include <sys/dnode.h>
  #include <sys/spa.h>
  #include <sys/zap.h>
  #include <libzfs.h>
*** 783,792 ****
--- 784,794 ----
  }
  
  void
  libzfs_mnttab_init(libzfs_handle_t *hdl)
  {
+         (void) mutex_init(&hdl->libzfs_mnttab_cache_lock, USYNC_THREAD, NULL);
          assert(avl_numnodes(&hdl->libzfs_mnttab_cache) == 0);
          avl_create(&hdl->libzfs_mnttab_cache, libzfs_mnttab_cache_compare,
              sizeof (mnttab_node_t), offsetof(mnttab_node_t, mtn_node));
  }
  
*** 823,832 ****
--- 825,835 ----
                  free(mtn->mtn_mt.mnt_fstype);
                  free(mtn->mtn_mt.mnt_mntopts);
                  free(mtn);
          }
          avl_destroy(&hdl->libzfs_mnttab_cache);
+         (void) mutex_destroy(&hdl->libzfs_mnttab_cache_lock);
  }
  
  void
  libzfs_mnttab_cache(libzfs_handle_t *hdl, boolean_t enable)
  {
*** 837,846 ****
--- 840,850 ----
  libzfs_mnttab_find(libzfs_handle_t *hdl, const char *fsname,
      struct mnttab *entry)
  {
          mnttab_node_t find;
          mnttab_node_t *mtn;
+         int ret = ENOENT;
  
          if (!hdl->libzfs_mnttab_enable) {
                  struct mnttab srch = { 0 };
  
                  if (avl_numnodes(&hdl->libzfs_mnttab_cache))
*** 847,895 ****
                          libzfs_mnttab_fini(hdl);
                  rewind(hdl->libzfs_mnttab);
                  srch.mnt_special = (char *)fsname;
                  srch.mnt_fstype = MNTTYPE_ZFS;
                  if (getmntany(hdl->libzfs_mnttab, entry, &srch) == 0)
!                         return (0);
!                 else
!                         return (ENOENT);
          }
  
          if (avl_numnodes(&hdl->libzfs_mnttab_cache) == 0)
                  libzfs_mnttab_update(hdl);
  
          find.mtn_mt.mnt_special = (char *)fsname;
          mtn = avl_find(&hdl->libzfs_mnttab_cache, &find, NULL);
          if (mtn) {
                  *entry = mtn->mtn_mt;
!                 return (0);
          }
!         return (ENOENT);
  }
  
  void
  libzfs_mnttab_add(libzfs_handle_t *hdl, const char *special,
      const char *mountp, const char *mntopts)
  {
          mnttab_node_t *mtn;
  
!         if (avl_numnodes(&hdl->libzfs_mnttab_cache) == 0)
!                 return;
          mtn = zfs_alloc(hdl, sizeof (mnttab_node_t));
          mtn->mtn_mt.mnt_special = zfs_strdup(hdl, special);
          mtn->mtn_mt.mnt_mountp = zfs_strdup(hdl, mountp);
          mtn->mtn_mt.mnt_fstype = zfs_strdup(hdl, MNTTYPE_ZFS);
          mtn->mtn_mt.mnt_mntopts = zfs_strdup(hdl, mntopts);
          avl_add(&hdl->libzfs_mnttab_cache, mtn);
  }
  
  void
  libzfs_mnttab_remove(libzfs_handle_t *hdl, const char *fsname)
  {
          mnttab_node_t find;
          mnttab_node_t *ret;
  
          find.mtn_mt.mnt_special = (char *)fsname;
          if ((ret = avl_find(&hdl->libzfs_mnttab_cache, (void *)&find, NULL))
              != NULL) {
                  avl_remove(&hdl->libzfs_mnttab_cache, ret);
                  free(ret->mtn_mt.mnt_special);
--- 851,903 ----
                          libzfs_mnttab_fini(hdl);
                  rewind(hdl->libzfs_mnttab);
                  srch.mnt_special = (char *)fsname;
                  srch.mnt_fstype = MNTTYPE_ZFS;
                  if (getmntany(hdl->libzfs_mnttab, entry, &srch) == 0)
!                         ret = 0;
!                 return (ret);
          }
  
+         (void) mutex_lock(&hdl->libzfs_mnttab_cache_lock);
          if (avl_numnodes(&hdl->libzfs_mnttab_cache) == 0)
                  libzfs_mnttab_update(hdl);
  
          find.mtn_mt.mnt_special = (char *)fsname;
          mtn = avl_find(&hdl->libzfs_mnttab_cache, &find, NULL);
          if (mtn) {
                  *entry = mtn->mtn_mt;
!                 ret = 0;
          }
!         (void) mutex_unlock(&hdl->libzfs_mnttab_cache_lock);
!         return (ret);
  }
  
  void
  libzfs_mnttab_add(libzfs_handle_t *hdl, const char *special,
      const char *mountp, const char *mntopts)
  {
          mnttab_node_t *mtn;
  
!         (void) mutex_lock(&hdl->libzfs_mnttab_cache_lock);
!         if (avl_numnodes(&hdl->libzfs_mnttab_cache) != 0) {
                  mtn = zfs_alloc(hdl, sizeof (mnttab_node_t));
                  mtn->mtn_mt.mnt_special = zfs_strdup(hdl, special);
                  mtn->mtn_mt.mnt_mountp = zfs_strdup(hdl, mountp);
                  mtn->mtn_mt.mnt_fstype = zfs_strdup(hdl, MNTTYPE_ZFS);
                  mtn->mtn_mt.mnt_mntopts = zfs_strdup(hdl, mntopts);
                  avl_add(&hdl->libzfs_mnttab_cache, mtn);
+         }
+         (void) mutex_unlock(&hdl->libzfs_mnttab_cache_lock);
  }
  
  void
  libzfs_mnttab_remove(libzfs_handle_t *hdl, const char *fsname)
  {
          mnttab_node_t find;
          mnttab_node_t *ret;
  
+         (void) mutex_lock(&hdl->libzfs_mnttab_cache_lock);
          find.mtn_mt.mnt_special = (char *)fsname;
          if ((ret = avl_find(&hdl->libzfs_mnttab_cache, (void *)&find, NULL))
              != NULL) {
                  avl_remove(&hdl->libzfs_mnttab_cache, ret);
                  free(ret->mtn_mt.mnt_special);
*** 896,905 ****
--- 904,914 ----
                  free(ret->mtn_mt.mnt_mountp);
                  free(ret->mtn_mt.mnt_fstype);
                  free(ret->mtn_mt.mnt_mntopts);
                  free(ret);
          }
+         (void) mutex_unlock(&hdl->libzfs_mnttab_cache_lock);
  }
  
  int
  zfs_spa_version(zfs_handle_t *zhp, int *spa_version)
  {