Add zpool_disable_datasets_os() / zfs_unmount_os()

zpool_disable_datasets_os():
macOS needs to do a bunch of work to kick everything off zvols.

zfs_unmount_os():
This allows us to unmount any zvols that may be mounted. Like with
zfs destroy foo/vol

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: John Kennedy <john.kennedy@delphix.com>
Signed-off-by: Jorgen Lundman <lundman@lundman.net>
Closes #12436

include/libzfs.h

@@ -839,7 +839,7 @@ _LIBZFS_H int zfs_unmount(zfs_handle_t *, const char *, int);
 _LIBZFS_H int zfs_unmountall(zfs_handle_t *, int);
 _LIBZFS_H int zfs_mount_delegation_check(void);
 
-#if defined(__linux__)
+#if defined(__linux__) || defined(__APPLE__)
 _LIBZFS_H int zfs_parse_mount_options(char *mntopts, unsigned long *mntflags,
     unsigned long *zfsflags, int sloppy, char *badopt, char *mtabopt);
 _LIBZFS_H void zfs_adjust_mount_options(zfs_handle_t *zhp, const char *mntpoint,
@@ -930,6 +930,8 @@ _LIBZFS_H int zfs_smb_acl_rename(libzfs_handle_t *, char *, char *, char *,
  */
 _LIBZFS_H int zpool_enable_datasets(zpool_handle_t *, const char *, int);
 _LIBZFS_H int zpool_disable_datasets(zpool_handle_t *, boolean_t);
+_LIBZFS_H void zpool_disable_datasets_os(zpool_handle_t *, boolean_t);
+_LIBZFS_H void zpool_disable_volume_os(const char *);
 
 /*
  * Parse a features file for -o compatibility

lib/libzfs/libzfs.abi

@@ -230,6 +230,8 @@
     <elf-symbol name='zpool_create' type='func-type' binding='global-binding' visibility='default-visibility' is-defined='yes'/>
     <elf-symbol name='zpool_destroy' type='func-type' binding='global-binding' visibility='default-visibility' is-defined='yes'/>
     <elf-symbol name='zpool_disable_datasets' type='func-type' binding='global-binding' visibility='default-visibility' is-defined='yes'/>
+    <elf-symbol name='zpool_disable_datasets_os' type='func-type' binding='global-binding' visibility='default-visibility' is-defined='yes'/>
+    <elf-symbol name='zpool_disable_volume_os' type='func-type' binding='global-binding' visibility='default-visibility' is-defined='yes'/>
     <elf-symbol name='zpool_discard_checkpoint' type='func-type' binding='global-binding' visibility='default-visibility' is-defined='yes'/>
     <elf-symbol name='zpool_enable_datasets' type='func-type' binding='global-binding' visibility='default-visibility' is-defined='yes'/>
     <elf-symbol name='zpool_events_clear' type='func-type' binding='global-binding' visibility='default-visibility' is-defined='yes'/>
@@ -2501,6 +2503,9 @@
     <function-decl name='qsort' mangled-name='qsort' visibility='default' binding='global' size-in-bits='64'>
       <return type-id='type-id-1'/>
     </function-decl>
+    <function-decl name='zpool_disable_datasets_os' mangled-name='zpool_disable_datasets_os' visibility='default' binding='global' size-in-bits='64'>
+      <return type-id='type-id-1'/>
+    </function-decl>
     <function-decl name='tpool_dispatch' mangled-name='tpool_dispatch' visibility='default' binding='global' size-in-bits='64'>
       <return type-id='type-id-1'/>
     </function-decl>
@@ -2540,6 +2545,9 @@
     <function-decl name='libzfs_mnttab_remove' mangled-name='libzfs_mnttab_remove' visibility='default' binding='global' size-in-bits='64'>
       <return type-id='type-id-1'/>
     </function-decl>
+    <function-decl name='zpool_disable_volume_os' mangled-name='zpool_disable_volume_os' visibility='default' binding='global' size-in-bits='64'>
+      <return type-id='type-id-1'/>
+    </function-decl>
     <function-decl name='zfs_crypto_get_encryption_root' mangled-name='zfs_crypto_get_encryption_root' visibility='default' binding='global' size-in-bits='64'>
       <return type-id='type-id-1'/>
     </function-decl>
@@ -3937,6 +3945,15 @@
     </function-type>
   </abi-instr>
   <abi-instr version='1.0' address-size='64' path='os/linux/libzfs_mount_os.c' comp-dir-path='/home/runner/work/zfs/zfs/lib/libzfs' language='LANG_C99'>
+    <function-decl name='zpool_disable_volume_os' mangled-name='zpool_disable_volume_os' visibility='default' binding='global' size-in-bits='64' elf-symbol-id='zpool_disable_volume_os'>
+      <parameter type-id='type-id-84' name='name'/>
+      <return type-id='type-id-1'/>
+    </function-decl>
+    <function-decl name='zpool_disable_datasets_os' mangled-name='zpool_disable_datasets_os' visibility='default' binding='global' size-in-bits='64' elf-symbol-id='zpool_disable_datasets_os'>
+      <parameter type-id='type-id-4' name='zhp'/>
+      <parameter type-id='type-id-9' name='force'/>
+      <return type-id='type-id-1'/>
+    </function-decl>
     <function-decl name='zfs_mount_delegation_check' mangled-name='zfs_mount_delegation_check' visibility='default' binding='global' size-in-bits='64' elf-symbol-id='zfs_mount_delegation_check'>
       <return type-id='type-id-2'/>
     </function-decl>

lib/libzfs/libzfs_mount.c

@@ -672,6 +672,8 @@ zfs_unmount(zfs_handle_t *zhp, const char *mountpoint, int flags)
 		}
 	}
 
+	zpool_disable_volume_os(zhp->zfs_name);
+
 	return (0);
 }
 
@@ -1637,6 +1639,8 @@ zpool_disable_datasets(zpool_handle_t *zhp, boolean_t force)
 			remove_mountpoint(sets[i].dataset);
 	}
 
+	zpool_disable_datasets_os(zhp, force);
+
 	ret = 0;
 out:
 	(void) fclose(mnttab);

lib/libzfs/os/freebsd/libzfs_zmount.c

@@ -133,3 +133,15 @@ zfs_mount_delegation_check(void)
 {
 	return (0);
 }
+
+/* Called from the tail end of zpool_disable_datasets() */
+void
+zpool_disable_datasets_os(zpool_handle_t *zhp, boolean_t force)
+{
+}
+
+/* Called from the tail end of zfs_unmount() */
+void
+zpool_disable_volume_os(const char *name)
+{
+}

lib/libzfs/os/linux/libzfs_mount_os.c

@@ -411,3 +411,15 @@ zfs_mount_delegation_check(void)
 {
 	return ((geteuid() != 0) ? EACCES : 0);
 }
+
+/* Called from the tail end of zpool_disable_datasets() */
+void
+zpool_disable_datasets_os(zpool_handle_t *zhp, boolean_t force)
+{
+}
+
+/* Called from the tail end of zfs_unmount() */
+void
+zpool_disable_volume_os(const char *name)
+{
+}