diff --git a/cmd/zdb/zdb.c b/cmd/zdb/zdb.c
index 83f79ad65..f185e2460 100644
--- a/cmd/zdb/zdb.c
+++ b/cmd/zdb/zdb.c
@@ -1117,7 +1117,7 @@ dump_zap(objset_t *os, uint64_t object, void *data, size_t size)
 {
 	(void) data, (void) size;
 	zap_cursor_t zc;
-	zap_attribute_t *attrp = zap_attribute_alloc();
+	zap_attribute_t *attrp = zap_attribute_long_alloc();
 	void *prop;
 	unsigned i;
 
@@ -1365,7 +1365,7 @@ dump_zpldir(objset_t *os, uint64_t object, void *data, size_t size)
 {
 	(void) data, (void) size;
 	zap_cursor_t zc;
-	zap_attribute_t *attrp = zap_attribute_alloc();
+	zap_attribute_t *attrp = zap_attribute_long_alloc();
 	const char *typenames[] = {
 		/* 0 */ "not specified",
 		/* 1 */ "FIFO",
diff --git a/cmd/zhack.c b/cmd/zhack.c
index 77284b895..f297afb65 100644
--- a/cmd/zhack.c
+++ b/cmd/zhack.c
@@ -203,7 +203,7 @@ static void
 dump_obj(objset_t *os, uint64_t obj, const char *name)
 {
 	zap_cursor_t zc;
-	zap_attribute_t *za = zap_attribute_alloc();
+	zap_attribute_t *za = zap_attribute_long_alloc();
 
 	(void) printf("%s_obj:\n", name);
 
diff --git a/include/os/freebsd/zfs/sys/zfs_vfsops_os.h b/include/os/freebsd/zfs/sys/zfs_vfsops_os.h
index 3e54f3e84..9fbca35cd 100644
--- a/include/os/freebsd/zfs/sys/zfs_vfsops_os.h
+++ b/include/os/freebsd/zfs/sys/zfs_vfsops_os.h
@@ -83,6 +83,7 @@ struct zfsvfs {
 	boolean_t	z_use_sa;	/* version allow system attributes */
 	boolean_t	z_xattr_sa;	/* allow xattrs to be stores as SA */
 	boolean_t	z_use_namecache; /* make use of FreeBSD name cache */
+	boolean_t	z_longname;	/* Dataset supports long names */
 	uint8_t		z_xattr;	/* xattr type in use */
 	uint64_t	z_version;	/* ZPL version */
 	uint64_t	z_shares_dir;	/* hidden shares dir */
diff --git a/include/os/freebsd/zfs/sys/zfs_znode_impl.h b/include/os/freebsd/zfs/sys/zfs_znode_impl.h
index 050fc3036..3727dca0f 100644
--- a/include/os/freebsd/zfs/sys/zfs_znode_impl.h
+++ b/include/os/freebsd/zfs/sys/zfs_znode_impl.h
@@ -179,7 +179,7 @@ extern void zfs_znode_free(struct znode *);
 extern zil_replay_func_t *const zfs_replay_vector[TX_MAX_TYPE];
 
 extern int zfs_znode_parent_and_name(struct znode *zp, struct znode **dzpp,
-    char *buf);
+    char *buf, uint64_t buflen);
 
 extern int zfs_rlimit_fsize(off_t fsize);
 #ifdef	__cplusplus
diff --git a/include/os/linux/zfs/sys/zfs_vfsops_os.h b/include/os/linux/zfs/sys/zfs_vfsops_os.h
index b4d5db21f..e742e8dc3 100644
--- a/include/os/linux/zfs/sys/zfs_vfsops_os.h
+++ b/include/os/linux/zfs/sys/zfs_vfsops_os.h
@@ -118,6 +118,7 @@ struct zfsvfs {
 	boolean_t	z_xattr_sa;	/* allow xattrs to be stores as SA */
 	boolean_t	z_draining;	/* is true when drain is active */
 	boolean_t	z_drain_cancel; /* signal the unlinked drain to stop */
+	boolean_t	z_longname;	/* Dataset supports long names */
 	uint64_t	z_version;	/* ZPL version */
 	uint64_t	z_shares_dir;	/* hidden shares dir */
 	dataset_kstats_t	z_kstat;	/* fs kstats */
diff --git a/include/os/linux/zfs/sys/zfs_vnops_os.h b/include/os/linux/zfs/sys/zfs_vnops_os.h
index f34eb153f..db33eda57 100644
--- a/include/os/linux/zfs/sys/zfs_vnops_os.h
+++ b/include/os/linux/zfs/sys/zfs_vnops_os.h
@@ -44,6 +44,7 @@ extern int zfs_write_simple(znode_t *zp, const void *data, size_t len,
     loff_t pos, size_t *resid);
 extern int zfs_lookup(znode_t *dzp, char *nm, znode_t **zpp, int flags,
     cred_t *cr, int *direntflags, pathname_t *realpnp);
+extern int zfs_get_name(znode_t *dzp, char *name, znode_t *zp);
 extern int zfs_create(znode_t *dzp, char *name, vattr_t *vap, int excl,
     int mode, znode_t **zpp, cred_t *cr, int flag, vsecattr_t *vsecp,
     zidmap_t *mnt_ns);
diff --git a/include/sys/fs/zfs.h b/include/sys/fs/zfs.h
index 3852fa031..cd2496bf7 100644
--- a/include/sys/fs/zfs.h
+++ b/include/sys/fs/zfs.h
@@ -81,6 +81,7 @@ typedef enum dmu_objset_type {
  * All of these include the terminating NUL byte.
  */
 #define	ZAP_MAXNAMELEN 256
+#define	ZAP_MAXNAMELEN_NEW 1024
 #define	ZAP_MAXVALUELEN (1024 * 8)
 #define	ZAP_OLDMAXVALUELEN 1024
 #define	ZFS_MAX_DATASET_NAME_LEN 256
@@ -194,6 +195,7 @@ typedef enum {
 	ZFS_PROP_PREFETCH,
 	ZFS_PROP_VOLTHREADING,
 	ZFS_PROP_DIRECT,
+	ZFS_PROP_LONGNAME,
 	ZFS_NUM_PROPS
 } zfs_prop_t;
 
diff --git a/include/sys/zap.h b/include/sys/zap.h
index ec37c3447..43e8bbea1 100644
--- a/include/sys/zap.h
+++ b/include/sys/zap.h
@@ -315,7 +315,7 @@ int zap_count(objset_t *ds, uint64_t zapobj, uint64_t *count);
  * match must be exact (ie, same as mask=-1ULL).
  */
 int zap_value_search(objset_t *os, uint64_t zapobj,
-    uint64_t value, uint64_t mask, char *name);
+    uint64_t value, uint64_t mask, char *name, uint64_t namelen);
 
 /*
  * Transfer all the entries from fromobj into intoobj.  Only works on
@@ -387,6 +387,7 @@ void zap_fini(void);
  * Alloc and free zap_attribute_t.
  */
 zap_attribute_t *zap_attribute_alloc(void);
+zap_attribute_t *zap_attribute_long_alloc(void);
 void zap_attribute_free(zap_attribute_t *attrp);
 
 /*
diff --git a/include/sys/zfs_ioctl.h b/include/sys/zfs_ioctl.h
index 8b50168cf..9e3d8150f 100644
--- a/include/sys/zfs_ioctl.h
+++ b/include/sys/zfs_ioctl.h
@@ -143,7 +143,7 @@ typedef enum drr_headertype {
  * default use of "zfs send" won't encounter the bug mentioned above.
  */
 #define	DMU_BACKUP_FEATURE_SWITCH_TO_LARGE_BLOCKS (1 << 27)
-/* flag #28 is reserved for a Nutanix feature */
+#define	DMU_BACKUP_FEATURE_LONGNAME		(1 << 28)
 
 /*
  * Mask of all supported backup features
@@ -154,7 +154,7 @@ typedef enum drr_headertype {
     DMU_BACKUP_FEATURE_COMPRESSED | DMU_BACKUP_FEATURE_LARGE_DNODE | \
     DMU_BACKUP_FEATURE_RAW | DMU_BACKUP_FEATURE_HOLDS | \
     DMU_BACKUP_FEATURE_REDACTED | DMU_BACKUP_FEATURE_SWITCH_TO_LARGE_BLOCKS | \
-    DMU_BACKUP_FEATURE_ZSTD)
+    DMU_BACKUP_FEATURE_ZSTD | DMU_BACKUP_FEATURE_LONGNAME)
 
 /* Are all features in the given flag word currently supported? */
 #define	DMU_STREAM_SUPPORTED(x)	(!((x) & ~DMU_BACKUP_FEATURE_MASK))
diff --git a/include/zfeature_common.h b/include/zfeature_common.h
index 5733a8187..1ca122d30 100644
--- a/include/zfeature_common.h
+++ b/include/zfeature_common.h
@@ -83,6 +83,7 @@ typedef enum spa_feature {
 	SPA_FEATURE_REDACTION_LIST_SPILL,
 	SPA_FEATURE_RAIDZ_EXPANSION,
 	SPA_FEATURE_FAST_DEDUP,
+	SPA_FEATURE_LONGNAME,
 	SPA_FEATURES
 } spa_feature_t;
 
diff --git a/lib/libzfs/libzfs.abi b/lib/libzfs/libzfs.abi
index 1f1f2fdff..1bbbc5dd5 100644
--- a/lib/libzfs/libzfs.abi
+++ b/lib/libzfs/libzfs.abi
@@ -2,7 +2,6 @@
   <elf-needed>
     <dependency name='libzfs_core.so.3'/>
     <dependency name='libnvpair.so.3'/>
-    <dependency name='libtirpc.so.3'/>
     <dependency name='libuuid.so.1'/>
     <dependency name='libblkid.so.1'/>
     <dependency name='libudev.so.1'/>
@@ -629,7 +628,7 @@
     <elf-symbol name='fletcher_4_superscalar_ops' size='128' type='object-type' binding='global-binding' visibility='default-visibility' is-defined='yes'/>
     <elf-symbol name='libzfs_config_ops' size='16' type='object-type' binding='global-binding' visibility='default-visibility' is-defined='yes'/>
     <elf-symbol name='sa_protocol_names' size='16' type='object-type' binding='global-binding' visibility='default-visibility' is-defined='yes'/>
-    <elf-symbol name='spa_feature_table' size='2352' type='object-type' binding='global-binding' visibility='default-visibility' is-defined='yes'/>
+    <elf-symbol name='spa_feature_table' size='2408' type='object-type' binding='global-binding' visibility='default-visibility' is-defined='yes'/>
     <elf-symbol name='zfeature_checks_disable' size='4' type='object-type' binding='global-binding' visibility='default-visibility' is-defined='yes'/>
     <elf-symbol name='zfs_deleg_perm_tab' size='512' type='object-type' binding='global-binding' visibility='default-visibility' is-defined='yes'/>
     <elf-symbol name='zfs_history_event_names' size='328' type='object-type' binding='global-binding' visibility='default-visibility' is-defined='yes'/>
@@ -765,25 +764,6 @@
       <parameter type-id='80f4b756'/>
       <return type-id='48b5725f'/>
     </function-decl>
-    <function-decl name='bsearch' visibility='default' binding='global' size-in-bits='64'>
-      <parameter type-id='eaa32e2f'/>
-      <parameter type-id='eaa32e2f'/>
-      <parameter type-id='b59d7dce'/>
-      <parameter type-id='b59d7dce'/>
-      <parameter type-id='aba7edd8'/>
-      <return type-id='eaa32e2f'/>
-    </function-decl>
-    <function-decl name='memmove' visibility='default' binding='global' size-in-bits='64'>
-      <parameter type-id='eaa32e2f'/>
-      <parameter type-id='eaa32e2f'/>
-      <parameter type-id='b59d7dce'/>
-      <return type-id='eaa32e2f'/>
-    </function-decl>
-    <function-decl name='strcat' visibility='default' binding='global' size-in-bits='64'>
-      <parameter type-id='26a90f95'/>
-      <parameter type-id='80f4b756'/>
-      <return type-id='26a90f95'/>
-    </function-decl>
     <function-type size-in-bits='64' id='276427e1'>
       <return type-id='95e97e5e'/>
     </function-type>
@@ -810,8 +790,9 @@
   </abi-instr>
   <abi-instr address-size='64' path='lib/libshare/os/linux/smb.c' language='LANG_C99'>
     <var-decl name='libshare_smb_type' type-id='d19dbca9' visibility='default'/>
-    <function-decl name='fgets' visibility='default' binding='global' size-in-bits='64'>
+    <function-decl name='__fgets_chk' visibility='default' binding='global' size-in-bits='64'>
       <parameter type-id='266fe297'/>
+      <parameter type-id='b59d7dce'/>
       <parameter type-id='95e97e5e'/>
       <parameter type-id='e75a27e9'/>
       <return type-id='26a90f95'/>
@@ -825,12 +806,6 @@
     <function-decl name='gettid' visibility='default' binding='global' size-in-bits='64'>
       <return type-id='3629bad8'/>
     </function-decl>
-    <function-decl name='vfprintf' visibility='default' binding='global' size-in-bits='64'>
-      <parameter type-id='e75a27e9'/>
-      <parameter type-id='9d26089a'/>
-      <parameter type-id='b7f2d5e6'/>
-      <return type-id='95e97e5e'/>
-    </function-decl>
     <function-decl name='prctl' visibility='default' binding='global' size-in-bits='64'>
       <parameter type-id='95e97e5e'/>
       <parameter is-variadic='yes'/>
@@ -1288,16 +1263,18 @@
     <qualified-type-def type-id='f077d3f8' restrict='yes' id='598aab80'/>
     <pointer-type-def type-id='928221d2' size-in-bits='64' id='323d93c1'/>
     <qualified-type-def type-id='323d93c1' restrict='yes' id='f1358bc3'/>
-    <function-decl name='mbstowcs' visibility='default' binding='global' size-in-bits='64'>
+    <function-decl name='__mbstowcs_chk' visibility='default' binding='global' size-in-bits='64'>
       <parameter type-id='f1358bc3'/>
       <parameter type-id='9d26089a'/>
       <parameter type-id='b59d7dce'/>
+      <parameter type-id='b59d7dce'/>
       <return type-id='b59d7dce'/>
     </function-decl>
-    <function-decl name='wcstombs' visibility='default' binding='global' size-in-bits='64'>
+    <function-decl name='__wcstombs_chk' visibility='default' binding='global' size-in-bits='64'>
       <parameter type-id='266fe297'/>
       <parameter type-id='598aab80'/>
       <parameter type-id='b59d7dce'/>
+      <parameter type-id='b59d7dce'/>
       <return type-id='b59d7dce'/>
     </function-decl>
   </abi-instr>
@@ -1315,19 +1292,6 @@
       <parameter type-id='822cd80b'/>
       <return type-id='95e97e5e'/>
     </function-decl>
-    <function-decl name='gnu_dev_major' visibility='default' binding='global' size-in-bits='64'>
-      <parameter type-id='35ed8932'/>
-      <return type-id='f0981eeb'/>
-    </function-decl>
-    <function-decl name='gnu_dev_minor' visibility='default' binding='global' size-in-bits='64'>
-      <parameter type-id='35ed8932'/>
-      <return type-id='f0981eeb'/>
-    </function-decl>
-    <function-decl name='gnu_dev_makedev' visibility='default' binding='global' size-in-bits='64'>
-      <parameter type-id='f0981eeb'/>
-      <parameter type-id='f0981eeb'/>
-      <return type-id='35ed8932'/>
-    </function-decl>
   </abi-instr>
   <abi-instr address-size='64' path='lib/libspl/timestamp.c' language='LANG_C99'>
     <typedef-decl name='nl_item' type-id='95e97e5e' id='03b79a94'/>
@@ -1476,10 +1440,6 @@
     <pointer-type-def type-id='6fcda10e' size-in-bits='64' id='ad33e5e7'/>
     <pointer-type-def type-id='66a0afc9' size-in-bits='64' id='f32b30e4'/>
     <qualified-type-def type-id='63e171df' restrict='yes' id='9e7a3a7d'/>
-    <function-decl name='__sysconf' visibility='default' binding='global' size-in-bits='64'>
-      <parameter type-id='95e97e5e'/>
-      <return type-id='bd54fe1a'/>
-    </function-decl>
     <function-decl name='pthread_self' visibility='default' binding='global' size-in-bits='64'>
       <return type-id='4051f5e7'/>
     </function-decl>
@@ -1613,6 +1573,10 @@
       <parameter type-id='0be2e71c'/>
       <return type-id='95e97e5e'/>
     </function-decl>
+    <function-decl name='__sysconf' visibility='default' binding='global' size-in-bits='64'>
+      <parameter type-id='95e97e5e'/>
+      <return type-id='bd54fe1a'/>
+    </function-decl>
     <function-decl name='tpool_abandon' mangled-name='tpool_abandon' visibility='default' binding='global' size-in-bits='64' elf-symbol-id='tpool_abandon'>
       <parameter type-id='9cf59a50' name='tpool'/>
       <return type-id='48b5725f'/>
@@ -1725,7 +1689,6 @@
     <type-decl name='unsigned char' size-in-bits='8' id='002ac4a6'/>
     <type-decl name='unsigned int' size-in-bits='32' id='f0981eeb'/>
     <type-decl name='unsigned long int' size-in-bits='64' id='7359adad'/>
-    <type-decl name='variadic parameter type' id='2c1145c5'/>
     <type-decl name='void' id='48b5725f'/>
     <typedef-decl name='uu_compare_fn_t' type-id='add6e811' id='40f93560'/>
     <typedef-decl name='uu_avl_pool_t' type-id='12a530a8' id='7f84e390'/>
@@ -1921,7 +1884,8 @@
       <enumerator name='ZFS_PROP_PREFETCH' value='96'/>
       <enumerator name='ZFS_PROP_VOLTHREADING' value='97'/>
       <enumerator name='ZFS_PROP_DIRECT' value='98'/>
-      <enumerator name='ZFS_NUM_PROPS' value='99'/>
+      <enumerator name='ZFS_PROP_LONGNAME' value='99'/>
+      <enumerator name='ZFS_NUM_PROPS' value='100'/>
     </enum-decl>
     <typedef-decl name='zfs_prop_t' type-id='4b000d60' id='58603c44'/>
     <enum-decl name='zprop_source_t' naming-typedef-id='a2256d42' id='5903f80e'>
@@ -1969,6 +1933,54 @@
     <typedef-decl name='longlong_t' type-id='1eb56b1e' id='9b3ff54f'/>
     <typedef-decl name='diskaddr_t' type-id='9b3ff54f' id='804dc465'/>
     <typedef-decl name='zoneid_t' type-id='3502e3ff' id='4da03624'/>
+    <typedef-decl name='__re_long_size_t' type-id='7359adad' id='ba516949'/>
+    <typedef-decl name='reg_syntax_t' type-id='7359adad' id='1b72c3b3'/>
+    <class-decl name='re_pattern_buffer' size-in-bits='512' is-struct='yes' visibility='default' id='19fc9a8c'>
+      <data-member access='public' layout-offset-in-bits='0'>
+        <var-decl name='buffer' type-id='33976309' visibility='default'/>
+      </data-member>
+      <data-member access='public' layout-offset-in-bits='64'>
+        <var-decl name='allocated' type-id='ba516949' visibility='default'/>
+      </data-member>
+      <data-member access='public' layout-offset-in-bits='128'>
+        <var-decl name='used' type-id='ba516949' visibility='default'/>
+      </data-member>
+      <data-member access='public' layout-offset-in-bits='192'>
+        <var-decl name='syntax' type-id='1b72c3b3' visibility='default'/>
+      </data-member>
+      <data-member access='public' layout-offset-in-bits='256'>
+        <var-decl name='fastmap' type-id='26a90f95' visibility='default'/>
+      </data-member>
+      <data-member access='public' layout-offset-in-bits='320'>
+        <var-decl name='translate' type-id='cf536864' visibility='default'/>
+      </data-member>
+      <data-member access='public' layout-offset-in-bits='384'>
+        <var-decl name='re_nsub' type-id='b59d7dce' visibility='default'/>
+      </data-member>
+      <data-member access='public' layout-offset-in-bits='448'>
+        <var-decl name='can_be_null' type-id='f0981eeb' visibility='default'/>
+      </data-member>
+      <data-member access='public' layout-offset-in-bits='449'>
+        <var-decl name='regs_allocated' type-id='f0981eeb' visibility='default'/>
+      </data-member>
+      <data-member access='public' layout-offset-in-bits='451'>
+        <var-decl name='fastmap_accurate' type-id='f0981eeb' visibility='default'/>
+      </data-member>
+      <data-member access='public' layout-offset-in-bits='452'>
+        <var-decl name='no_sub' type-id='f0981eeb' visibility='default'/>
+      </data-member>
+      <data-member access='public' layout-offset-in-bits='453'>
+        <var-decl name='not_bol' type-id='f0981eeb' visibility='default'/>
+      </data-member>
+      <data-member access='public' layout-offset-in-bits='454'>
+        <var-decl name='not_eol' type-id='f0981eeb' visibility='default'/>
+      </data-member>
+      <data-member access='public' layout-offset-in-bits='455'>
+        <var-decl name='newline_anchor' type-id='f0981eeb' visibility='default'/>
+      </data-member>
+    </class-decl>
+    <typedef-decl name='regex_t' type-id='19fc9a8c' id='aca3bac8'/>
+    <typedef-decl name='uintptr_t' type-id='7359adad' id='e475ab95'/>
     <union-decl name='pthread_mutex_t' size-in-bits='320' naming-typedef-id='7a6844eb' visibility='default' id='70681f9b'>
       <data-member access='public'>
         <var-decl name='__data' type-id='4c734837' visibility='default'/>
@@ -2024,54 +2036,6 @@
     <typedef-decl name='__int32_t' type-id='95e97e5e' id='33f57a65'/>
     <typedef-decl name='__uint32_t' type-id='f0981eeb' id='62f1140c'/>
     <typedef-decl name='__uint64_t' type-id='7359adad' id='8910171f'/>
-    <typedef-decl name='__re_long_size_t' type-id='7359adad' id='ba516949'/>
-    <typedef-decl name='reg_syntax_t' type-id='7359adad' id='1b72c3b3'/>
-    <class-decl name='re_pattern_buffer' size-in-bits='512' is-struct='yes' visibility='default' id='19fc9a8c'>
-      <data-member access='public' layout-offset-in-bits='0'>
-        <var-decl name='buffer' type-id='33976309' visibility='default'/>
-      </data-member>
-      <data-member access='public' layout-offset-in-bits='64'>
-        <var-decl name='allocated' type-id='ba516949' visibility='default'/>
-      </data-member>
-      <data-member access='public' layout-offset-in-bits='128'>
-        <var-decl name='used' type-id='ba516949' visibility='default'/>
-      </data-member>
-      <data-member access='public' layout-offset-in-bits='192'>
-        <var-decl name='syntax' type-id='1b72c3b3' visibility='default'/>
-      </data-member>
-      <data-member access='public' layout-offset-in-bits='256'>
-        <var-decl name='fastmap' type-id='26a90f95' visibility='default'/>
-      </data-member>
-      <data-member access='public' layout-offset-in-bits='320'>
-        <var-decl name='translate' type-id='cf536864' visibility='default'/>
-      </data-member>
-      <data-member access='public' layout-offset-in-bits='384'>
-        <var-decl name='re_nsub' type-id='b59d7dce' visibility='default'/>
-      </data-member>
-      <data-member access='public' layout-offset-in-bits='448'>
-        <var-decl name='can_be_null' type-id='f0981eeb' visibility='default'/>
-      </data-member>
-      <data-member access='public' layout-offset-in-bits='449'>
-        <var-decl name='regs_allocated' type-id='f0981eeb' visibility='default'/>
-      </data-member>
-      <data-member access='public' layout-offset-in-bits='451'>
-        <var-decl name='fastmap_accurate' type-id='f0981eeb' visibility='default'/>
-      </data-member>
-      <data-member access='public' layout-offset-in-bits='452'>
-        <var-decl name='no_sub' type-id='f0981eeb' visibility='default'/>
-      </data-member>
-      <data-member access='public' layout-offset-in-bits='453'>
-        <var-decl name='not_bol' type-id='f0981eeb' visibility='default'/>
-      </data-member>
-      <data-member access='public' layout-offset-in-bits='454'>
-        <var-decl name='not_eol' type-id='f0981eeb' visibility='default'/>
-      </data-member>
-      <data-member access='public' layout-offset-in-bits='455'>
-        <var-decl name='newline_anchor' type-id='f0981eeb' visibility='default'/>
-      </data-member>
-    </class-decl>
-    <typedef-decl name='regex_t' type-id='19fc9a8c' id='aca3bac8'/>
-    <typedef-decl name='uintptr_t' type-id='7359adad' id='e475ab95'/>
     <typedef-decl name='size_t' type-id='7359adad' id='b59d7dce'/>
     <class-decl name='libzfs_handle' size-in-bits='18240' is-struct='yes' visibility='default' id='c8a9d9d8'>
       <data-member access='public' layout-offset-in-bits='0'>
@@ -2236,9 +2200,6 @@
     <class-decl name='uu_avl' is-struct='yes' visibility='default' is-declaration-only='yes' id='4af029d1'/>
     <class-decl name='uu_avl_pool' is-struct='yes' visibility='default' is-declaration-only='yes' id='12a530a8'/>
     <class-decl name='uu_avl_walk' is-struct='yes' visibility='default' is-declaration-only='yes' id='e70a39e3'/>
-    <function-decl name='uu_error' visibility='default' binding='global' size-in-bits='64'>
-      <return type-id='8f92235e'/>
-    </function-decl>
     <function-decl name='uu_avl_pool_create' visibility='default' binding='global' size-in-bits='64'>
       <parameter type-id='80f4b756'/>
       <parameter type-id='b59d7dce'/>
@@ -2402,14 +2363,6 @@
     <function-decl name='getzoneid' mangled-name='getzoneid' visibility='default' binding='global' size-in-bits='64' elf-symbol-id='getzoneid'>
       <return type-id='4da03624'/>
     </function-decl>
-    <function-decl name='libspl_assertf' mangled-name='libspl_assertf' visibility='default' binding='global' size-in-bits='64' elf-symbol-id='libspl_assertf'>
-      <parameter type-id='80f4b756'/>
-      <parameter type-id='80f4b756'/>
-      <parameter type-id='95e97e5e'/>
-      <parameter type-id='80f4b756'/>
-      <parameter is-variadic='yes'/>
-      <return type-id='48b5725f'/>
-    </function-decl>
     <function-decl name='sa_commit_shares' mangled-name='sa_commit_shares' visibility='default' binding='global' size-in-bits='64' elf-symbol-id='sa_commit_shares'>
       <parameter type-id='9155d4b5'/>
       <return type-id='48b5725f'/>
@@ -2426,13 +2379,6 @@
       <parameter type-id='b59d7dce'/>
       <return type-id='b59d7dce'/>
     </function-decl>
-    <function-decl name='__assert_fail' visibility='default' binding='global' size-in-bits='64'>
-      <parameter type-id='80f4b756'/>
-      <parameter type-id='80f4b756'/>
-      <parameter type-id='f0981eeb'/>
-      <parameter type-id='80f4b756'/>
-      <return type-id='48b5725f'/>
-    </function-decl>
     <function-decl name='free' visibility='default' binding='global' size-in-bits='64'>
       <parameter type-id='eaa32e2f'/>
       <return type-id='48b5725f'/>
@@ -2500,6 +2446,7 @@
     <array-type-def dimensions='1' type-id='b96825af' size-in-bits='24' id='d3490169'>
       <subrange length='3' type-id='7359adad' id='56f209d2'/>
     </array-type-def>
+    <type-decl name='variadic parameter type' id='2c1145c5'/>
     <typedef-decl name='zpool_iter_f' type-id='3aebb66f' id='fa476e62'/>
     <enum-decl name='data_type_t' naming-typedef-id='8d0687d2' id='aeeae136'>
       <underlying-type type-id='9cac1fee'/>
@@ -2848,6 +2795,14 @@
       <parameter type-id='3fa542f0'/>
       <return type-id='5ce45b60'/>
     </function-decl>
+    <function-decl name='libspl_assertf' mangled-name='libspl_assertf' visibility='default' binding='global' size-in-bits='64' elf-symbol-id='libspl_assertf'>
+      <parameter type-id='80f4b756'/>
+      <parameter type-id='80f4b756'/>
+      <parameter type-id='95e97e5e'/>
+      <parameter type-id='80f4b756'/>
+      <parameter is-variadic='yes'/>
+      <return type-id='48b5725f'/>
+    </function-decl>
     <function-decl name='__errno_location' visibility='default' binding='global' size-in-bits='64'>
       <return type-id='7292109c'/>
     </function-decl>
@@ -2861,11 +2816,6 @@
       <parameter type-id='80f4b756'/>
       <return type-id='26a90f95'/>
     </function-decl>
-    <function-decl name='strcpy' visibility='default' binding='global' size-in-bits='64'>
-      <parameter type-id='26a90f95'/>
-      <parameter type-id='80f4b756'/>
-      <return type-id='26a90f95'/>
-    </function-decl>
     <function-decl name='strchr' visibility='default' binding='global' size-in-bits='64'>
       <parameter type-id='80f4b756'/>
       <parameter type-id='95e97e5e'/>
@@ -3021,6 +2971,18 @@
       <enumerator name='ZPOOL_NUM_PROPS' value='39'/>
     </enum-decl>
     <typedef-decl name='zpool_prop_t' type-id='af1ba157' id='5d0c23fb'/>
+    <typedef-decl name='regoff_t' type-id='95e97e5e' id='54a2a2a8'/>
+    <class-decl name='regmatch_t' size-in-bits='64' is-struct='yes' naming-typedef-id='1b941664' visibility='default' id='4f932615'>
+      <data-member access='public' layout-offset-in-bits='0'>
+        <var-decl name='rm_so' type-id='54a2a2a8' visibility='default'/>
+      </data-member>
+      <data-member access='public' layout-offset-in-bits='32'>
+        <var-decl name='rm_eo' type-id='54a2a2a8' visibility='default'/>
+      </data-member>
+    </class-decl>
+    <typedef-decl name='regmatch_t' type-id='4f932615' id='1b941664'/>
+    <typedef-decl name='__sighandler_t' type-id='03347643' id='8cdd9566'/>
+    <typedef-decl name='ssize_t' type-id='41060289' id='79a0948f'/>
     <class-decl name='sigaction' size-in-bits='1216' is-struct='yes' visibility='default' id='fe391c48'>
       <data-member access='public' layout-offset-in-bits='0'>
         <var-decl name='__sigaction_handler' type-id='ac5ab595' visibility='default'/>
@@ -3341,18 +3303,6 @@
         <var-decl name='_unused2' type-id='664ac0b7' visibility='default'/>
       </data-member>
     </class-decl>
-    <typedef-decl name='regoff_t' type-id='95e97e5e' id='54a2a2a8'/>
-    <class-decl name='regmatch_t' size-in-bits='64' is-struct='yes' naming-typedef-id='1b941664' visibility='default' id='4f932615'>
-      <data-member access='public' layout-offset-in-bits='0'>
-        <var-decl name='rm_so' type-id='54a2a2a8' visibility='default'/>
-      </data-member>
-      <data-member access='public' layout-offset-in-bits='32'>
-        <var-decl name='rm_eo' type-id='54a2a2a8' visibility='default'/>
-      </data-member>
-    </class-decl>
-    <typedef-decl name='regmatch_t' type-id='4f932615' id='1b941664'/>
-    <typedef-decl name='__sighandler_t' type-id='03347643' id='8cdd9566'/>
-    <typedef-decl name='ssize_t' type-id='41060289' id='79a0948f'/>
     <pointer-type-def type-id='aa12d1ba' size-in-bits='64' id='822cd80b'/>
     <qualified-type-def type-id='822cd80b' restrict='yes' id='e75a27e9'/>
     <pointer-type-def type-id='ec1ed955' size-in-bits='64' id='dca988a5'/>
@@ -3554,42 +3504,18 @@
       <parameter type-id='80f4b756'/>
       <return type-id='822cd80b'/>
     </function-decl>
-    <function-decl name='printf' visibility='default' binding='global' size-in-bits='64'>
-      <parameter type-id='80f4b756'/>
-      <parameter is-variadic='yes'/>
-      <return type-id='95e97e5e'/>
-    </function-decl>
-    <function-decl name='snprintf' visibility='default' binding='global' size-in-bits='64'>
-      <parameter type-id='26a90f95'/>
-      <parameter type-id='b59d7dce'/>
-      <parameter type-id='80f4b756'/>
-      <parameter is-variadic='yes'/>
-      <return type-id='95e97e5e'/>
-    </function-decl>
-    <function-decl name='asprintf' visibility='default' binding='global' size-in-bits='64'>
-      <parameter type-id='8c85230f'/>
-      <parameter type-id='9d26089a'/>
-      <parameter is-variadic='yes'/>
-      <return type-id='95e97e5e'/>
-    </function-decl>
     <function-decl name='fputc' visibility='default' binding='global' size-in-bits='64'>
       <parameter type-id='95e97e5e'/>
       <parameter type-id='822cd80b'/>
       <return type-id='95e97e5e'/>
     </function-decl>
-    <function-decl name='getline' visibility='default' binding='global' size-in-bits='64'>
+    <function-decl name='__getdelim' visibility='default' binding='global' size-in-bits='64'>
       <parameter type-id='8c85230f'/>
       <parameter type-id='d19b2c25'/>
+      <parameter type-id='95e97e5e'/>
       <parameter type-id='e75a27e9'/>
       <return type-id='41060289'/>
     </function-decl>
-    <function-decl name='fread' visibility='default' binding='global' size-in-bits='64'>
-      <parameter type-id='1b7446cd'/>
-      <parameter type-id='b59d7dce'/>
-      <parameter type-id='b59d7dce'/>
-      <parameter type-id='e75a27e9'/>
-      <return type-id='b59d7dce'/>
-    </function-decl>
     <function-decl name='rewind' visibility='default' binding='global' size-in-bits='64'>
       <parameter type-id='822cd80b'/>
       <return type-id='48b5725f'/>
@@ -3611,12 +3537,6 @@
       <parameter type-id='b59d7dce'/>
       <return type-id='eaa32e2f'/>
     </function-decl>
-    <function-decl name='memcpy' visibility='default' binding='global' size-in-bits='64'>
-      <parameter type-id='eaa32e2f'/>
-      <parameter type-id='eaa32e2f'/>
-      <parameter type-id='b59d7dce'/>
-      <return type-id='eaa32e2f'/>
-    </function-decl>
     <function-decl name='strdup' visibility='default' binding='global' size-in-bits='64'>
       <parameter type-id='80f4b756'/>
       <return type-id='26a90f95'/>
@@ -3641,12 +3561,6 @@
       <parameter type-id='95e97e5e'/>
       <return type-id='95e97e5e'/>
     </function-decl>
-    <function-decl name='read' visibility='default' binding='global' size-in-bits='64'>
-      <parameter type-id='95e97e5e'/>
-      <parameter type-id='eaa32e2f'/>
-      <parameter type-id='b59d7dce'/>
-      <return type-id='79a0948f'/>
-    </function-decl>
     <function-decl name='getpid' visibility='default' binding='global' size-in-bits='64'>
       <return type-id='3629bad8'/>
     </function-decl>
@@ -3658,6 +3572,40 @@
       <parameter type-id='80f4b756'/>
       <return type-id='95e97e5e'/>
     </function-decl>
+    <function-decl name='__open_too_many_args' visibility='default' binding='global' size-in-bits='64'>
+      <return type-id='48b5725f'/>
+    </function-decl>
+    <function-decl name='__open_missing_mode' visibility='default' binding='global' size-in-bits='64'>
+      <return type-id='48b5725f'/>
+    </function-decl>
+    <function-decl name='__printf_chk' visibility='default' binding='global' size-in-bits='64'>
+      <parameter type-id='95e97e5e'/>
+      <parameter type-id='80f4b756'/>
+      <parameter is-variadic='yes'/>
+      <return type-id='95e97e5e'/>
+    </function-decl>
+    <function-decl name='__asprintf_chk' visibility='default' binding='global' size-in-bits='64'>
+      <parameter type-id='8c85230f'/>
+      <parameter type-id='95e97e5e'/>
+      <parameter type-id='9d26089a'/>
+      <parameter is-variadic='yes'/>
+      <return type-id='95e97e5e'/>
+    </function-decl>
+    <function-decl name='__fread_chk' visibility='default' binding='global' size-in-bits='64'>
+      <parameter type-id='1b7446cd'/>
+      <parameter type-id='b59d7dce'/>
+      <parameter type-id='b59d7dce'/>
+      <parameter type-id='b59d7dce'/>
+      <parameter type-id='e75a27e9'/>
+      <return type-id='b59d7dce'/>
+    </function-decl>
+    <function-decl name='__read_chk' visibility='default' binding='global' size-in-bits='64'>
+      <parameter type-id='95e97e5e'/>
+      <parameter type-id='eaa32e2f'/>
+      <parameter type-id='b59d7dce'/>
+      <parameter type-id='b59d7dce'/>
+      <return type-id='79a0948f'/>
+    </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' elf-symbol-id='zfs_crypto_get_encryption_root'>
       <parameter type-id='9200a744' name='zhp'/>
       <parameter type-id='37e3bd22' name='is_encroot'/>
@@ -3828,55 +3776,6 @@
         <var-decl name='mnt_mntopts' type-id='26a90f95' visibility='default'/>
       </data-member>
     </class-decl>
-    <union-decl name='pthread_mutexattr_t' size-in-bits='32' naming-typedef-id='8afd6070' visibility='default' id='7300eb00'>
-      <data-member access='public'>
-        <var-decl name='__size' type-id='8e0573fd' visibility='default'/>
-      </data-member>
-      <data-member access='public'>
-        <var-decl name='__align' type-id='95e97e5e' visibility='default'/>
-      </data-member>
-    </union-decl>
-    <typedef-decl name='pthread_mutexattr_t' type-id='7300eb00' id='8afd6070'/>
-    <typedef-decl name='int64_t' type-id='0c9942d2' id='9da381c4'/>
-    <typedef-decl name='__int64_t' type-id='bd54fe1a' id='0c9942d2'/>
-    <typedef-decl name='__gid_t' type-id='f0981eeb' id='d94ec6d9'/>
-    <typedef-decl name='__time_t' type-id='bd54fe1a' id='65eda9c0'/>
-    <class-decl name='tm' size-in-bits='448' is-struct='yes' visibility='default' id='dddf6ca2'>
-      <data-member access='public' layout-offset-in-bits='0'>
-        <var-decl name='tm_sec' type-id='95e97e5e' visibility='default'/>
-      </data-member>
-      <data-member access='public' layout-offset-in-bits='32'>
-        <var-decl name='tm_min' type-id='95e97e5e' visibility='default'/>
-      </data-member>
-      <data-member access='public' layout-offset-in-bits='64'>
-        <var-decl name='tm_hour' type-id='95e97e5e' visibility='default'/>
-      </data-member>
-      <data-member access='public' layout-offset-in-bits='96'>
-        <var-decl name='tm_mday' type-id='95e97e5e' visibility='default'/>
-      </data-member>
-      <data-member access='public' layout-offset-in-bits='128'>
-        <var-decl name='tm_mon' type-id='95e97e5e' visibility='default'/>
-      </data-member>
-      <data-member access='public' layout-offset-in-bits='160'>
-        <var-decl name='tm_year' type-id='95e97e5e' visibility='default'/>
-      </data-member>
-      <data-member access='public' layout-offset-in-bits='192'>
-        <var-decl name='tm_wday' type-id='95e97e5e' visibility='default'/>
-      </data-member>
-      <data-member access='public' layout-offset-in-bits='224'>
-        <var-decl name='tm_yday' type-id='95e97e5e' visibility='default'/>
-      </data-member>
-      <data-member access='public' layout-offset-in-bits='256'>
-        <var-decl name='tm_isdst' type-id='95e97e5e' visibility='default'/>
-      </data-member>
-      <data-member access='public' layout-offset-in-bits='320'>
-        <var-decl name='tm_gmtoff' type-id='bd54fe1a' visibility='default'/>
-      </data-member>
-      <data-member access='public' layout-offset-in-bits='384'>
-        <var-decl name='tm_zone' type-id='80f4b756' visibility='default'/>
-      </data-member>
-    </class-decl>
-    <typedef-decl name='time_t' type-id='65eda9c0' id='c9d12d66'/>
     <class-decl name='group' size-in-bits='256' is-struct='yes' visibility='default' id='01a1b934'>
       <data-member access='public' layout-offset-in-bits='0'>
         <var-decl name='gr_name' type-id='26a90f95' visibility='default'/>
@@ -3934,6 +3833,55 @@
         <var-decl name='pw_shell' type-id='26a90f95' visibility='default'/>
       </data-member>
     </class-decl>
+    <union-decl name='pthread_mutexattr_t' size-in-bits='32' naming-typedef-id='8afd6070' visibility='default' id='7300eb00'>
+      <data-member access='public'>
+        <var-decl name='__size' type-id='8e0573fd' visibility='default'/>
+      </data-member>
+      <data-member access='public'>
+        <var-decl name='__align' type-id='95e97e5e' visibility='default'/>
+      </data-member>
+    </union-decl>
+    <typedef-decl name='pthread_mutexattr_t' type-id='7300eb00' id='8afd6070'/>
+    <typedef-decl name='int64_t' type-id='0c9942d2' id='9da381c4'/>
+    <typedef-decl name='__int64_t' type-id='bd54fe1a' id='0c9942d2'/>
+    <typedef-decl name='__gid_t' type-id='f0981eeb' id='d94ec6d9'/>
+    <typedef-decl name='__time_t' type-id='bd54fe1a' id='65eda9c0'/>
+    <class-decl name='tm' size-in-bits='448' is-struct='yes' visibility='default' id='dddf6ca2'>
+      <data-member access='public' layout-offset-in-bits='0'>
+        <var-decl name='tm_sec' type-id='95e97e5e' visibility='default'/>
+      </data-member>
+      <data-member access='public' layout-offset-in-bits='32'>
+        <var-decl name='tm_min' type-id='95e97e5e' visibility='default'/>
+      </data-member>
+      <data-member access='public' layout-offset-in-bits='64'>
+        <var-decl name='tm_hour' type-id='95e97e5e' visibility='default'/>
+      </data-member>
+      <data-member access='public' layout-offset-in-bits='96'>
+        <var-decl name='tm_mday' type-id='95e97e5e' visibility='default'/>
+      </data-member>
+      <data-member access='public' layout-offset-in-bits='128'>
+        <var-decl name='tm_mon' type-id='95e97e5e' visibility='default'/>
+      </data-member>
+      <data-member access='public' layout-offset-in-bits='160'>
+        <var-decl name='tm_year' type-id='95e97e5e' visibility='default'/>
+      </data-member>
+      <data-member access='public' layout-offset-in-bits='192'>
+        <var-decl name='tm_wday' type-id='95e97e5e' visibility='default'/>
+      </data-member>
+      <data-member access='public' layout-offset-in-bits='224'>
+        <var-decl name='tm_yday' type-id='95e97e5e' visibility='default'/>
+      </data-member>
+      <data-member access='public' layout-offset-in-bits='256'>
+        <var-decl name='tm_isdst' type-id='95e97e5e' visibility='default'/>
+      </data-member>
+      <data-member access='public' layout-offset-in-bits='320'>
+        <var-decl name='tm_gmtoff' type-id='bd54fe1a' visibility='default'/>
+      </data-member>
+      <data-member access='public' layout-offset-in-bits='384'>
+        <var-decl name='tm_zone' type-id='80f4b756' visibility='default'/>
+      </data-member>
+    </class-decl>
+    <typedef-decl name='time_t' type-id='65eda9c0' id='c9d12d66'/>
     <typedef-decl name='uid_t' type-id='cc5fcceb' id='354978ed'/>
     <typedef-decl name='prop_changelist_t' type-id='d86edc51' id='eae6431d'/>
     <pointer-type-def type-id='fba6cb51' size-in-bits='64' id='32adbf30'/>
@@ -4434,15 +4382,11 @@
       <parameter type-id='8f2c7109'/>
       <return type-id='95e97e5e'/>
     </function-decl>
-    <function-decl name='fprintf' visibility='default' binding='global' size-in-bits='64'>
-      <parameter type-id='e75a27e9'/>
+    <function-decl name='strtol' visibility='default' binding='global' size-in-bits='64'>
       <parameter type-id='9d26089a'/>
-      <parameter is-variadic='yes'/>
-      <return type-id='95e97e5e'/>
-    </function-decl>
-    <function-decl name='atoi' visibility='default' binding='global' size-in-bits='64'>
-      <parameter type-id='80f4b756'/>
-      <return type-id='95e97e5e'/>
+      <parameter type-id='8c85230f'/>
+      <parameter type-id='95e97e5e'/>
+      <return type-id='bd54fe1a'/>
     </function-decl>
     <function-decl name='strtoul' visibility='default' binding='global' size-in-bits='64'>
       <parameter type-id='9d26089a'/>
@@ -4473,12 +4417,6 @@
       <parameter type-id='9d26089a'/>
       <return type-id='26a90f95'/>
     </function-decl>
-    <function-decl name='ioctl' visibility='default' binding='global' size-in-bits='64'>
-      <parameter type-id='95e97e5e'/>
-      <parameter type-id='7359adad'/>
-      <parameter is-variadic='yes'/>
-      <return type-id='95e97e5e'/>
-    </function-decl>
     <function-decl name='strftime' visibility='default' binding='global' size-in-bits='64'>
       <parameter type-id='266fe297'/>
       <parameter type-id='b59d7dce'/>
@@ -4491,6 +4429,19 @@
       <parameter type-id='f099ad08'/>
       <return type-id='d915a820'/>
     </function-decl>
+    <function-decl name='__fprintf_chk' visibility='default' binding='global' size-in-bits='64'>
+      <parameter type-id='e75a27e9'/>
+      <parameter type-id='95e97e5e'/>
+      <parameter type-id='9d26089a'/>
+      <parameter is-variadic='yes'/>
+      <return type-id='95e97e5e'/>
+    </function-decl>
+    <function-decl name='ioctl' visibility='default' binding='global' size-in-bits='64'>
+      <parameter type-id='95e97e5e'/>
+      <parameter type-id='7359adad'/>
+      <parameter is-variadic='yes'/>
+      <return type-id='95e97e5e'/>
+    </function-decl>
     <function-decl name='zfs_type_to_name' mangled-name='zfs_type_to_name' visibility='default' binding='global' size-in-bits='64' elf-symbol-id='zfs_type_to_name'>
       <parameter type-id='2e45de5d' name='type'/>
       <return type-id='80f4b756'/>
@@ -5156,24 +5107,6 @@
       <parameter type-id='7292109c'/>
       <return type-id='95e97e5e'/>
     </function-decl>
-    <function-decl name='memset' visibility='default' binding='global' size-in-bits='64'>
-      <parameter type-id='eaa32e2f'/>
-      <parameter type-id='95e97e5e'/>
-      <parameter type-id='b59d7dce'/>
-      <return type-id='eaa32e2f'/>
-    </function-decl>
-    <function-decl name='fstat64' visibility='default' binding='global' size-in-bits='64'>
-      <parameter type-id='95e97e5e'/>
-      <parameter type-id='62f7a03d'/>
-      <return type-id='95e97e5e'/>
-    </function-decl>
-    <function-decl name='pread64' visibility='default' binding='global' size-in-bits='64'>
-      <parameter type-id='95e97e5e'/>
-      <parameter type-id='eaa32e2f'/>
-      <parameter type-id='b59d7dce'/>
-      <parameter type-id='724e4de6'/>
-      <return type-id='79a0948f'/>
-    </function-decl>
     <function-decl name='pwrite64' visibility='default' binding='global' size-in-bits='64'>
       <parameter type-id='95e97e5e'/>
       <parameter type-id='eaa32e2f'/>
@@ -5181,6 +5114,19 @@
       <parameter type-id='724e4de6'/>
       <return type-id='79a0948f'/>
     </function-decl>
+    <function-decl name='__pread64_chk' visibility='default' binding='global' size-in-bits='64'>
+      <parameter type-id='95e97e5e'/>
+      <parameter type-id='eaa32e2f'/>
+      <parameter type-id='b59d7dce'/>
+      <parameter type-id='724e4de6'/>
+      <parameter type-id='b59d7dce'/>
+      <return type-id='79a0948f'/>
+    </function-decl>
+    <function-decl name='fstat64' visibility='default' binding='global' size-in-bits='64'>
+      <parameter type-id='95e97e5e'/>
+      <parameter type-id='62f7a03d'/>
+      <return type-id='95e97e5e'/>
+    </function-decl>
     <function-decl name='zcmd_write_conf_nvlist' visibility='default' binding='global' size-in-bits='64'>
       <parameter type-id='b0382bb3'/>
       <parameter type-id='e4ec4540'/>
@@ -5381,6 +5327,9 @@
     </class-decl>
     <typedef-decl name='get_all_cb_t' type-id='803dac95' id='9b293607'/>
     <typedef-decl name='tpool_t' type-id='88d1b7f9' id='b1bbf10d'/>
+    <typedef-decl name='DIR' type-id='20cd73f2' id='54a5d683'/>
+    <typedef-decl name='mode_t' type-id='e1c52942' id='d50d396c'/>
+    <typedef-decl name='__compar_fn_t' type-id='585e1de9' id='aba7edd8'/>
     <class-decl name='dirent64' size-in-bits='2240' is-struct='yes' visibility='default' id='5725d813'>
       <data-member access='public' layout-offset-in-bits='0'>
         <var-decl name='d_ino' type-id='71288a47' visibility='default'/>
@@ -5494,9 +5443,6 @@
     <typedef-decl name='__fsblkcnt64_t' type-id='7359adad' id='95fe1a02'/>
     <typedef-decl name='__fsfilcnt64_t' type-id='7359adad' id='0c3a4dde'/>
     <typedef-decl name='__fsword_t' type-id='bd54fe1a' id='6028cbfe'/>
-    <typedef-decl name='DIR' type-id='20cd73f2' id='54a5d683'/>
-    <typedef-decl name='mode_t' type-id='e1c52942' id='d50d396c'/>
-    <typedef-decl name='__compar_fn_t' type-id='585e1de9' id='aba7edd8'/>
     <pointer-type-def type-id='54a5d683' size-in-bits='64' id='f09217ba'/>
     <pointer-type-def type-id='5725d813' size-in-bits='64' id='07b96073'/>
     <pointer-type-def type-id='9b293607' size-in-bits='64' id='77bf1784'/>
@@ -5568,14 +5514,14 @@
       <parameter type-id='9155d4b5'/>
       <return type-id='48b5725f'/>
     </function-decl>
-    <function-decl name='closedir' visibility='default' binding='global' size-in-bits='64'>
-      <parameter type-id='f09217ba'/>
-      <return type-id='95e97e5e'/>
-    </function-decl>
     <function-decl name='fdopendir' visibility='default' binding='global' size-in-bits='64'>
       <parameter type-id='95e97e5e'/>
       <return type-id='f09217ba'/>
     </function-decl>
+    <function-decl name='closedir' visibility='default' binding='global' size-in-bits='64'>
+      <parameter type-id='f09217ba'/>
+      <return type-id='95e97e5e'/>
+    </function-decl>
     <function-decl name='readdir64' visibility='default' binding='global' size-in-bits='64'>
       <parameter type-id='f09217ba'/>
       <return type-id='07b96073'/>
@@ -5587,15 +5533,21 @@
       <parameter type-id='aba7edd8'/>
       <return type-id='48b5725f'/>
     </function-decl>
+    <function-decl name='rmdir' visibility='default' binding='global' size-in-bits='64'>
+      <parameter type-id='80f4b756'/>
+      <return type-id='95e97e5e'/>
+    </function-decl>
+    <function-decl name='__openat_too_many_args' visibility='default' binding='global' size-in-bits='64'>
+      <return type-id='48b5725f'/>
+    </function-decl>
+    <function-decl name='__openat_missing_mode' visibility='default' binding='global' size-in-bits='64'>
+      <return type-id='48b5725f'/>
+    </function-decl>
     <function-decl name='statfs64' visibility='default' binding='global' size-in-bits='64'>
       <parameter type-id='80f4b756'/>
       <parameter type-id='7fd094c8'/>
       <return type-id='95e97e5e'/>
     </function-decl>
-    <function-decl name='rmdir' visibility='default' binding='global' size-in-bits='64'>
-      <parameter type-id='80f4b756'/>
-      <return type-id='95e97e5e'/>
-    </function-decl>
     <function-decl name='zfs_realloc' visibility='default' binding='global' size-in-bits='64'>
       <parameter type-id='b0382bb3'/>
       <parameter type-id='eaa32e2f'/>
@@ -6077,7 +6029,8 @@
       <enumerator name='SPA_FEATURE_REDACTION_LIST_SPILL' value='39'/>
       <enumerator name='SPA_FEATURE_RAIDZ_EXPANSION' value='40'/>
       <enumerator name='SPA_FEATURE_FAST_DEDUP' value='41'/>
-      <enumerator name='SPA_FEATURES' value='42'/>
+      <enumerator name='SPA_FEATURE_LONGNAME' value='42'/>
+      <enumerator name='SPA_FEATURES' value='43'/>
     </enum-decl>
     <typedef-decl name='spa_feature_t' type-id='33ecb627' id='d6618c78'/>
     <qualified-type-def type-id='80f4b756' const='yes' id='b99c00c9'/>
@@ -6262,10 +6215,6 @@
       <parameter type-id='80f4b756'/>
       <return type-id='c19b74c3'/>
     </function-decl>
-    <function-decl name='zpool_prop_unsupported' mangled-name='zpool_prop_unsupported' visibility='default' binding='global' size-in-bits='64' elf-symbol-id='zpool_prop_unsupported'>
-      <parameter type-id='80f4b756'/>
-      <return type-id='c19b74c3'/>
-    </function-decl>
     <function-decl name='zpool_prop_index_to_string' mangled-name='zpool_prop_index_to_string' visibility='default' binding='global' size-in-bits='64' elf-symbol-id='zpool_prop_index_to_string'>
       <parameter type-id='5d0c23fb'/>
       <parameter type-id='9c313c2d'/>
@@ -6404,11 +6353,6 @@
       <parameter type-id='95e97e5e'/>
       <return type-id='3a47d82b'/>
     </function-decl>
-    <function-decl name='realpath' visibility='default' binding='global' size-in-bits='64'>
-      <parameter type-id='9d26089a'/>
-      <parameter type-id='266fe297'/>
-      <return type-id='26a90f95'/>
-    </function-decl>
     <function-decl name='memcmp' visibility='default' binding='global' size-in-bits='64'>
       <parameter type-id='eaa32e2f'/>
       <parameter type-id='eaa32e2f'/>
@@ -6421,6 +6365,17 @@
       <parameter type-id='8c85230f'/>
       <return type-id='26a90f95'/>
     </function-decl>
+    <function-decl name='ctime_r' visibility='default' binding='global' size-in-bits='64'>
+      <parameter type-id='d6e2847c'/>
+      <parameter type-id='266fe297'/>
+      <return type-id='26a90f95'/>
+    </function-decl>
+    <function-decl name='__realpath_chk' visibility='default' binding='global' size-in-bits='64'>
+      <parameter type-id='9d26089a'/>
+      <parameter type-id='266fe297'/>
+      <parameter type-id='b59d7dce'/>
+      <return type-id='26a90f95'/>
+    </function-decl>
     <function-decl name='munmap' visibility='default' binding='global' size-in-bits='64'>
       <parameter type-id='eaa32e2f'/>
       <parameter type-id='b59d7dce'/>
@@ -6431,11 +6386,6 @@
       <parameter type-id='f1cadedf'/>
       <return type-id='95e97e5e'/>
     </function-decl>
-    <function-decl name='ctime_r' visibility='default' binding='global' size-in-bits='64'>
-      <parameter type-id='d6e2847c'/>
-      <parameter type-id='266fe297'/>
-      <return type-id='26a90f95'/>
-    </function-decl>
     <function-decl name='zpool_standard_error' visibility='default' binding='global' size-in-bits='64'>
       <parameter type-id='b0382bb3'/>
       <parameter type-id='95e97e5e'/>
@@ -7463,6 +7413,23 @@
         <var-decl name='drr_checksum' type-id='39730d0b' visibility='default'/>
       </data-member>
     </class-decl>
+    <class-decl name='__cancel_jmp_buf_tag' size-in-bits='576' is-struct='yes' visibility='default' id='8901473c'>
+      <data-member access='public' layout-offset-in-bits='0'>
+        <var-decl name='__cancel_jmp_buf' type-id='379a1ab7' visibility='default'/>
+      </data-member>
+      <data-member access='public' layout-offset-in-bits='512'>
+        <var-decl name='__mask_was_saved' type-id='95e97e5e' visibility='default'/>
+      </data-member>
+    </class-decl>
+    <class-decl name='__pthread_unwind_buf_t' size-in-bits='832' is-struct='yes' naming-typedef-id='4423cf7f' visibility='default' id='a0abc656'>
+      <data-member access='public' layout-offset-in-bits='0'>
+        <var-decl name='__cancel_jmp_buf' type-id='f5da478b' visibility='default'/>
+      </data-member>
+      <data-member access='public' layout-offset-in-bits='576'>
+        <var-decl name='__pad' type-id='209ef23f' visibility='default'/>
+      </data-member>
+    </class-decl>
+    <typedef-decl name='__pthread_unwind_buf_t' type-id='a0abc656' id='4423cf7f'/>
     <typedef-decl name='__jmp_buf' type-id='5d4efd44' id='379a1ab7'/>
     <typedef-decl name='__clockid_t' type-id='95e97e5e' id='08f9a87a'/>
     <typedef-decl name='__timer_t' type-id='eaa32e2f' id='df209b60'/>
@@ -7509,23 +7476,6 @@
       </data-member>
     </class-decl>
     <typedef-decl name='timer_t' type-id='df209b60' id='b07ae406'/>
-    <class-decl name='__cancel_jmp_buf_tag' size-in-bits='576' is-struct='yes' visibility='default' id='8901473c'>
-      <data-member access='public' layout-offset-in-bits='0'>
-        <var-decl name='__cancel_jmp_buf' type-id='379a1ab7' visibility='default'/>
-      </data-member>
-      <data-member access='public' layout-offset-in-bits='512'>
-        <var-decl name='__mask_was_saved' type-id='95e97e5e' visibility='default'/>
-      </data-member>
-    </class-decl>
-    <class-decl name='__pthread_unwind_buf_t' size-in-bits='832' is-struct='yes' naming-typedef-id='4423cf7f' visibility='default' id='a0abc656'>
-      <data-member access='public' layout-offset-in-bits='0'>
-        <var-decl name='__cancel_jmp_buf' type-id='f5da478b' visibility='default'/>
-      </data-member>
-      <data-member access='public' layout-offset-in-bits='576'>
-        <var-decl name='__pad' type-id='209ef23f' visibility='default'/>
-      </data-member>
-    </class-decl>
-    <typedef-decl name='__pthread_unwind_buf_t' type-id='a0abc656' id='4423cf7f'/>
     <typedef-decl name='Byte' type-id='002ac4a6' id='efb9ba06'/>
     <typedef-decl name='uLong' type-id='7359adad' id='5bbcce85'/>
     <typedef-decl name='Bytef' type-id='efb9ba06' id='c1606520'/>
@@ -7720,12 +7670,6 @@
       <parameter type-id='eaa32e2f'/>
       <return type-id='95e97e5e'/>
     </function-decl>
-    <function-decl name='pthread_sigmask' visibility='default' binding='global' size-in-bits='64'>
-      <parameter type-id='95e97e5e'/>
-      <parameter type-id='5a8729d0'/>
-      <parameter type-id='65e6ec45'/>
-      <return type-id='95e97e5e'/>
-    </function-decl>
     <function-decl name='pthread_exit' visibility='default' binding='global' size-in-bits='64'>
       <parameter type-id='eaa32e2f'/>
       <return type-id='48b5725f'/>
@@ -7743,12 +7687,6 @@
       <parameter type-id='95e97e5e'/>
       <return type-id='95e97e5e'/>
     </function-decl>
-    <function-decl name='sprintf' visibility='default' binding='global' size-in-bits='64'>
-      <parameter type-id='26a90f95'/>
-      <parameter type-id='80f4b756'/>
-      <parameter is-variadic='yes'/>
-      <return type-id='95e97e5e'/>
-    </function-decl>
     <function-decl name='perror' visibility='default' binding='global' size-in-bits='64'>
       <parameter type-id='80f4b756'/>
       <return type-id='48b5725f'/>
@@ -7793,6 +7731,12 @@
     <function-decl name='pause' visibility='default' binding='global' size-in-bits='64'>
       <return type-id='95e97e5e'/>
     </function-decl>
+    <function-decl name='pthread_sigmask' visibility='default' binding='global' size-in-bits='64'>
+      <parameter type-id='95e97e5e'/>
+      <parameter type-id='5a8729d0'/>
+      <parameter type-id='65e6ec45'/>
+      <return type-id='95e97e5e'/>
+    </function-decl>
     <function-decl name='uncompress' visibility='default' binding='global' size-in-bits='64'>
       <parameter type-id='4c667223'/>
       <parameter type-id='60db3356'/>
@@ -8094,6 +8038,10 @@
       <parameter type-id='80f4b756'/>
       <return type-id='26a90f95'/>
     </function-decl>
+    <function-decl name='zpool_prop_unsupported' mangled-name='zpool_prop_unsupported' visibility='default' binding='global' size-in-bits='64' elf-symbol-id='zpool_prop_unsupported'>
+      <parameter type-id='80f4b756'/>
+      <return type-id='c19b74c3'/>
+    </function-decl>
     <function-decl name='zpool_feature_init' mangled-name='zpool_feature_init' visibility='default' binding='global' size-in-bits='64' elf-symbol-id='zpool_feature_init'>
       <return type-id='48b5725f'/>
     </function-decl>
@@ -8161,11 +8109,6 @@
       <parameter type-id='62f7a03d'/>
       <return type-id='95e97e5e'/>
     </function-decl>
-    <function-decl name='pow' visibility='default' binding='global' size-in-bits='64'>
-      <parameter type-id='a0eb0f08'/>
-      <parameter type-id='a0eb0f08'/>
-      <return type-id='a0eb0f08'/>
-    </function-decl>
     <function-decl name='__ctype_toupper_loc' visibility='default' binding='global' size-in-bits='64'>
       <return type-id='24f95ba5'/>
     </function-decl>
@@ -8183,26 +8126,9 @@
       <parameter type-id='d33f11cb'/>
       <return type-id='48b5725f'/>
     </function-decl>
-    <function-decl name='vprintf' visibility='default' binding='global' size-in-bits='64'>
-      <parameter type-id='80f4b756'/>
-      <parameter type-id='b7f2d5e6'/>
-      <return type-id='95e97e5e'/>
-    </function-decl>
-    <function-decl name='vsnprintf' visibility='default' binding='global' size-in-bits='64'>
-      <parameter type-id='26a90f95'/>
-      <parameter type-id='b59d7dce'/>
-      <parameter type-id='80f4b756'/>
-      <parameter type-id='b7f2d5e6'/>
-      <return type-id='95e97e5e'/>
-    </function-decl>
-    <function-decl name='vasprintf' visibility='default' binding='global' size-in-bits='64'>
-      <parameter type-id='8c85230f'/>
-      <parameter type-id='9d26089a'/>
-      <parameter type-id='b7f2d5e6'/>
-      <return type-id='95e97e5e'/>
-    </function-decl>
-    <function-decl name='putchar' visibility='default' binding='global' size-in-bits='64'>
+    <function-decl name='putc' visibility='default' binding='global' size-in-bits='64'>
       <parameter type-id='95e97e5e'/>
+      <parameter type-id='822cd80b'/>
       <return type-id='95e97e5e'/>
     </function-decl>
     <function-decl name='puts' visibility='default' binding='global' size-in-bits='64'>
@@ -8239,12 +8165,6 @@
       <parameter type-id='b59d7dce'/>
       <return type-id='95e97e5e'/>
     </function-decl>
-    <function-decl name='waitpid' visibility='default' binding='global' size-in-bits='64'>
-      <parameter type-id='3629bad8'/>
-      <parameter type-id='7292109c'/>
-      <parameter type-id='95e97e5e'/>
-      <return type-id='3629bad8'/>
-    </function-decl>
     <function-decl name='access' visibility='default' binding='global' size-in-bits='64'>
       <parameter type-id='80f4b756'/>
       <parameter type-id='95e97e5e'/>
@@ -8284,6 +8204,31 @@
     <function-decl name='fork' visibility='default' binding='global' size-in-bits='64'>
       <return type-id='3629bad8'/>
     </function-decl>
+    <function-decl name='pow' visibility='default' binding='global' size-in-bits='64'>
+      <parameter type-id='a0eb0f08'/>
+      <parameter type-id='a0eb0f08'/>
+      <return type-id='a0eb0f08'/>
+    </function-decl>
+    <function-decl name='__vfprintf_chk' visibility='default' binding='global' size-in-bits='64'>
+      <parameter type-id='e75a27e9'/>
+      <parameter type-id='95e97e5e'/>
+      <parameter type-id='9d26089a'/>
+      <parameter type-id='b7f2d5e6'/>
+      <return type-id='95e97e5e'/>
+    </function-decl>
+    <function-decl name='__vasprintf_chk' visibility='default' binding='global' size-in-bits='64'>
+      <parameter type-id='8c85230f'/>
+      <parameter type-id='95e97e5e'/>
+      <parameter type-id='9d26089a'/>
+      <parameter type-id='b7f2d5e6'/>
+      <return type-id='95e97e5e'/>
+    </function-decl>
+    <function-decl name='waitpid' visibility='default' binding='global' size-in-bits='64'>
+      <parameter type-id='3629bad8'/>
+      <parameter type-id='7292109c'/>
+      <parameter type-id='95e97e5e'/>
+      <return type-id='3629bad8'/>
+    </function-decl>
     <function-decl name='namespace_clear' visibility='default' binding='global' size-in-bits='64'>
       <parameter type-id='b0382bb3'/>
       <return type-id='48b5725f'/>
@@ -8454,6 +8399,9 @@
   </abi-instr>
   <abi-instr address-size='64' path='lib/libzfs/os/linux/libzfs_mount_os.c' language='LANG_C99'>
     <pointer-type-def type-id='7359adad' size-in-bits='64' id='1d2c2b85'/>
+    <function-decl name='geteuid' visibility='default' binding='global' size-in-bits='64'>
+      <return type-id='cc5fcceb'/>
+    </function-decl>
     <function-decl name='mount' visibility='default' binding='global' size-in-bits='64'>
       <parameter type-id='80f4b756'/>
       <parameter type-id='80f4b756'/>
@@ -8467,9 +8415,6 @@
       <parameter type-id='95e97e5e'/>
       <return type-id='95e97e5e'/>
     </function-decl>
-    <function-decl name='geteuid' visibility='default' binding='global' size-in-bits='64'>
-      <return type-id='cc5fcceb'/>
-    </function-decl>
     <function-decl name='zfs_parse_mount_options' mangled-name='zfs_parse_mount_options' visibility='default' binding='global' size-in-bits='64' elf-symbol-id='zfs_parse_mount_options'>
       <parameter type-id='80f4b756' name='mntopts'/>
       <parameter type-id='1d2c2b85' name='mntflags'/>
@@ -8655,11 +8600,12 @@
       </data-member>
     </class-decl>
     <pointer-type-def type-id='b440e872' size-in-bits='64' id='3ac36db0'/>
-    <function-decl name='strtol' visibility='default' binding='global' size-in-bits='64'>
-      <parameter type-id='9d26089a'/>
-      <parameter type-id='8c85230f'/>
+    <function-decl name='__poll_chk' visibility='default' binding='global' size-in-bits='64'>
+      <parameter type-id='3ac36db0'/>
+      <parameter type-id='555eef66'/>
       <parameter type-id='95e97e5e'/>
-      <return type-id='bd54fe1a'/>
+      <parameter type-id='7359adad'/>
+      <return type-id='95e97e5e'/>
     </function-decl>
     <function-decl name='inotify_init1' visibility='default' binding='global' size-in-bits='64'>
       <parameter type-id='95e97e5e'/>
@@ -8671,12 +8617,6 @@
       <parameter type-id='8f92235e'/>
       <return type-id='95e97e5e'/>
     </function-decl>
-    <function-decl name='poll' visibility='default' binding='global' size-in-bits='64'>
-      <parameter type-id='3ac36db0'/>
-      <parameter type-id='555eef66'/>
-      <parameter type-id='95e97e5e'/>
-      <return type-id='95e97e5e'/>
-    </function-decl>
     <function-decl name='timerfd_create' visibility='default' binding='global' size-in-bits='64'>
       <parameter type-id='08f9a87a'/>
       <parameter type-id='95e97e5e'/>
@@ -8725,10 +8665,11 @@
       <parameter type-id='80f4b756'/>
       <return type-id='80f4b756'/>
     </function-decl>
-    <function-decl name='readlink' visibility='default' binding='global' size-in-bits='64'>
+    <function-decl name='__readlink_chk' visibility='default' binding='global' size-in-bits='64'>
       <parameter type-id='9d26089a'/>
       <parameter type-id='266fe297'/>
       <parameter type-id='b59d7dce'/>
+      <parameter type-id='b59d7dce'/>
       <return type-id='79a0948f'/>
     </function-decl>
     <function-decl name='zfs_get_enclosure_sysfs_path' mangled-name='zfs_get_enclosure_sysfs_path' visibility='default' binding='global' size-in-bits='64' elf-symbol-id='zfs_get_enclosure_sysfs_path'>
@@ -8754,10 +8695,10 @@
     <class-decl name='blkid_struct_dev_iterate' is-struct='yes' visibility='default' is-declaration-only='yes' id='d88420d6'/>
     <class-decl name='udev_list_entry' is-struct='yes' visibility='default' is-declaration-only='yes' id='e7dbdca3'/>
     <typedef-decl name='pool_vdev_iter_f' type-id='6c16a6c8' id='dff793e0'/>
-    <typedef-decl name='__useconds_t' type-id='f0981eeb' id='4e80d4b1'/>
     <typedef-decl name='blkid_dev' type-id='8433f053' id='f47b023a'/>
     <typedef-decl name='blkid_cache' type-id='940e3afc' id='0882dfdf'/>
     <typedef-decl name='blkid_dev_iterate' type-id='b8fa2efc' id='f4760fa7'/>
+    <typedef-decl name='__useconds_t' type-id='f0981eeb' id='4e80d4b1'/>
     <pointer-type-def type-id='0882dfdf' size-in-bits='64' id='2e3e7caa'/>
     <pointer-type-def type-id='f47b023a' size-in-bits='64' id='d87f9b75'/>
     <pointer-type-def type-id='09286066' size-in-bits='64' id='940e3afc'/>
@@ -9268,8 +9209,8 @@
     </function-decl>
   </abi-instr>
   <abi-instr address-size='64' path='module/zcommon/zfeature_common.c' language='LANG_C99'>
-    <array-type-def dimensions='1' type-id='83f29ca2' size-in-bits='18816' id='b937914f'>
-      <subrange length='42' type-id='7359adad' id='cb7c937f'/>
+    <array-type-def dimensions='1' type-id='83f29ca2' size-in-bits='19264' id='bd39d632'>
+      <subrange length='43' type-id='7359adad' id='8f7e73a2'/>
     </array-type-def>
     <enum-decl name='zfeature_flags' id='6db816a4'>
       <underlying-type type-id='9cac1fee'/>
@@ -9313,6 +9254,7 @@
       </data-member>
     </class-decl>
     <typedef-decl name='zfeature_info_t' type-id='1178d146' id='83f29ca2'/>
+    <typedef-decl name='__free_fn_t' type-id='b7f9d8e6' id='3ff5e51e'/>
     <class-decl name='dirent' size-in-bits='2240' is-struct='yes' visibility='default' id='611586a1'>
       <data-member access='public' layout-offset-in-bits='0'>
         <var-decl name='d_ino' type-id='71288a47' visibility='default'/>
@@ -9330,7 +9272,6 @@
         <var-decl name='d_name' type-id='d1617432' visibility='default'/>
       </data-member>
     </class-decl>
-    <typedef-decl name='__free_fn_t' type-id='b7f9d8e6' id='3ff5e51e'/>
     <class-decl name='zfs_mod_supported_features' size-in-bits='128' is-struct='yes' visibility='default' id='3eee3342'>
       <data-member access='public' layout-offset-in-bits='0'>
         <var-decl name='tree' type-id='eaa32e2f' visibility='default'/>
@@ -9346,7 +9287,7 @@
     <pointer-type-def type-id='611586a1' size-in-bits='64' id='2e243169'/>
     <qualified-type-def type-id='eaa32e2f' const='yes' id='83be723c'/>
     <pointer-type-def type-id='83be723c' size-in-bits='64' id='7acd98a2'/>
-    <var-decl name='spa_feature_table' type-id='b937914f' mangled-name='spa_feature_table' visibility='default' elf-symbol-id='spa_feature_table'/>
+    <var-decl name='spa_feature_table' type-id='bd39d632' mangled-name='spa_feature_table' visibility='default' elf-symbol-id='spa_feature_table'/>
     <var-decl name='zfeature_checks_disable' type-id='c19b74c3' mangled-name='zfeature_checks_disable' visibility='default' elf-symbol-id='zfeature_checks_disable'/>
     <function-decl name='opendir' visibility='default' binding='global' size-in-bits='64'>
       <parameter type-id='80f4b756'/>
diff --git a/man/man7/zpool-features.7 b/man/man7/zpool-features.7
index fe7715496..ad9755ba5 100644
--- a/man/man7/zpool-features.7
+++ b/man/man7/zpool-features.7
@@ -723,6 +723,23 @@ instead of scattering multiple writes to all the metaslab spacemaps.
 .Pp
 \*[instant-never]
 .
+.feature org.zfsonlinux longname no extensible_dataset
+This feature allows creating files and directories with name up to 1023 bytes
+in length.
+A new dataset property
+.Sy longname
+is also introduced to toggle longname support for each dataset individually.
+This property can be disabled even if it contains longname files.
+In such case, new file cannot be created with longname but existing longname
+files can still be looked up.
+.Pp
+This feature becomes
+.Sy active
+when a file name greater than 255 is created in a dataset, and returns to
+being
+.Sy enabled
+when all such datasets are destroyed.
+.
 .feature org.illumos lz4_compress no
 .Sy lz4
 is a high-performance real-time compression algorithm that
diff --git a/module/os/freebsd/zfs/zfs_dir.c b/module/os/freebsd/zfs/zfs_dir.c
index 1ac0ab1ed..1358c0486 100644
--- a/module/os/freebsd/zfs/zfs_dir.c
+++ b/module/os/freebsd/zfs/zfs_dir.c
@@ -627,6 +627,15 @@ zfs_link_create(znode_t *dzp, const char *name, znode_t *zp, dmu_tx_t *tx,
 		return (error);
 	}
 
+	/*
+	 * If we added a longname activate the SPA_FEATURE_LONGNAME.
+	 */
+	if (strlen(name) >= ZAP_MAXNAMELEN) {
+		dsl_dataset_t *ds = dmu_objset_ds(zfsvfs->z_os);
+		ds->ds_feature_activation[SPA_FEATURE_LONGNAME] =
+		    (void *)B_TRUE;
+	}
+
 	SA_ADD_BULK_ATTR(bulk, count, SA_ZPL_PARENT(zfsvfs), NULL,
 	    &dzp->z_id, sizeof (dzp->z_id));
 	SA_ADD_BULK_ATTR(bulk, count, SA_ZPL_FLAGS(zfsvfs), NULL,
diff --git a/module/os/freebsd/zfs/zfs_vfsops.c b/module/os/freebsd/zfs/zfs_vfsops.c
index b96393df4..a3fac1636 100644
--- a/module/os/freebsd/zfs/zfs_vfsops.c
+++ b/module/os/freebsd/zfs/zfs_vfsops.c
@@ -614,6 +614,14 @@ acl_type_changed_cb(void *arg, uint64_t newval)
 	zfsvfs->z_acl_type = newval;
 }
 
+static void
+longname_changed_cb(void *arg, uint64_t newval)
+{
+	zfsvfs_t *zfsvfs = arg;
+
+	zfsvfs->z_longname = newval;
+}
+
 static int
 zfs_register_callbacks(vfs_t *vfsp)
 {
@@ -751,6 +759,8 @@ zfs_register_callbacks(vfs_t *vfsp)
 	error = error ? error : dsl_prop_register(ds,
 	    zfs_prop_to_name(ZFS_PROP_ACLINHERIT), acl_inherit_changed_cb,
 	    zfsvfs);
+	error = error ? error : dsl_prop_register(ds,
+	    zfs_prop_to_name(ZFS_PROP_LONGNAME), longname_changed_cb, zfsvfs);
 	dsl_pool_config_exit(dmu_objset_pool(os), FTAG);
 	if (error)
 		goto unregister;
@@ -1489,7 +1499,8 @@ zfs_statfs(vfs_t *vfsp, struct statfs *statp)
 	strlcpy(statp->f_mntonname, vfsp->mnt_stat.f_mntonname,
 	    sizeof (statp->f_mntonname));
 
-	statp->f_namemax = MAXNAMELEN - 1;
+	statp->f_namemax =
+	    zfsvfs->z_longname ? (ZAP_MAXNAMELEN_NEW - 1) : (MAXNAMELEN - 1);
 
 	zfs_exit(zfsvfs, FTAG);
 	return (0);
diff --git a/module/os/freebsd/zfs/zfs_vnops_os.c b/module/os/freebsd/zfs/zfs_vnops_os.c
index 9df1fef60..60deab1f5 100644
--- a/module/os/freebsd/zfs/zfs_vnops_os.c
+++ b/module/os/freebsd/zfs/zfs_vnops_os.c
@@ -892,6 +892,14 @@ zfs_lookup(vnode_t *dvp, const char *nm, vnode_t **vpp,
 	return (error);
 }
 
+static inline bool
+is_nametoolong(zfsvfs_t *zfsvfs, const char *name)
+{
+	size_t dlen = strlen(name);
+	return ((!zfsvfs->z_longname && dlen >= ZAP_MAXNAMELEN) ||
+	    dlen >= ZAP_MAXNAMELEN_NEW);
+}
+
 /*
  * Attempt to create a new entry in a directory.  If the entry
  * already exists, truncate the file if permissible, else return
@@ -937,6 +945,9 @@ zfs_create(znode_t *dzp, const char *name, vattr_t *vap, int excl, int mode,
 	vnode_t	*dvp = ZTOV(dzp);
 #endif
 
+	if (is_nametoolong(zfsvfs, name))
+		return (SET_ERROR(ENAMETOOLONG));
+
 	/*
 	 * If we have an ephemeral id, ACL, or XVATTR then
 	 * make sure file system is at proper version
@@ -1301,6 +1312,9 @@ zfs_mkdir(znode_t *dzp, const char *dirname, vattr_t *vap, znode_t **zpp,
 
 	ASSERT3U(vap->va_type, ==, VDIR);
 
+	if (is_nametoolong(zfsvfs, dirname))
+		return (SET_ERROR(ENAMETOOLONG));
+
 	/*
 	 * If we have an ephemeral id, ACL, or XVATTR then
 	 * make sure file system is at proper version
@@ -1616,7 +1630,7 @@ zfs_readdir(vnode_t *vp, zfs_uio_t *uio, cred_t *cr, int *eofp,
 	os = zfsvfs->z_os;
 	offset = zfs_uio_offset(uio);
 	prefetch = zp->z_zn_prefetch;
-	zap = zap_attribute_alloc();
+	zap = zap_attribute_long_alloc();
 
 	/*
 	 * Initialize the iterator cursor.
@@ -3294,6 +3308,9 @@ zfs_rename(znode_t *sdzp, const char *sname, znode_t *tdzp, const char *tname,
 	int error;
 	svp = tvp = NULL;
 
+	if (is_nametoolong(tdzp->z_zfsvfs, tname))
+		return (SET_ERROR(ENAMETOOLONG));
+
 	if (rflags != 0 || wo_vap != NULL)
 		return (SET_ERROR(EINVAL));
 
@@ -3358,6 +3375,9 @@ zfs_symlink(znode_t *dzp, const char *name, vattr_t *vap,
 
 	ASSERT3S(vap->va_type, ==, VLNK);
 
+	if (is_nametoolong(zfsvfs, name))
+		return (SET_ERROR(ENAMETOOLONG));
+
 	if ((error = zfs_enter_verify_zp(zfsvfs, dzp, FTAG)) != 0)
 		return (error);
 	zilog = zfsvfs->z_log;
@@ -3540,6 +3560,9 @@ zfs_link(znode_t *tdzp, znode_t *szp, const char *name, cred_t *cr,
 
 	ASSERT3S(ZTOV(tdzp)->v_type, ==, VDIR);
 
+	if (is_nametoolong(zfsvfs, name))
+		return (SET_ERROR(ENAMETOOLONG));
+
 	if ((error = zfs_enter_verify_zp(zfsvfs, tdzp, FTAG)) != 0)
 		return (error);
 	zilog = zfsvfs->z_log;
@@ -5996,7 +6019,8 @@ zfs_vptocnp(struct vop_vptocnp_args *ap)
 		znode_t *dzp;
 		size_t len;
 
-		error = zfs_znode_parent_and_name(zp, &dzp, name);
+		error = zfs_znode_parent_and_name(zp, &dzp, name,
+		    sizeof (name));
 		if (error == 0) {
 			len = strlen(name);
 			if (*ap->a_buflen < len)
diff --git a/module/os/freebsd/zfs/zfs_znode_os.c b/module/os/freebsd/zfs/zfs_znode_os.c
index fea34273b..a31ecc367 100644
--- a/module/os/freebsd/zfs/zfs_znode_os.c
+++ b/module/os/freebsd/zfs/zfs_znode_os.c
@@ -1792,7 +1792,8 @@ zfs_znode_update_vfs(znode_t *zp)
 }
 
 int
-zfs_znode_parent_and_name(znode_t *zp, znode_t **dzpp, char *buf)
+zfs_znode_parent_and_name(znode_t *zp, znode_t **dzpp, char *buf,
+    uint64_t buflen)
 {
 	zfsvfs_t *zfsvfs = zp->z_zfsvfs;
 	uint64_t parent;
@@ -1814,7 +1815,7 @@ zfs_znode_parent_and_name(znode_t *zp, znode_t **dzpp, char *buf)
 		return (SET_ERROR(EINVAL));
 
 	err = zap_value_search(zfsvfs->z_os, parent, zp->z_id,
-	    ZFS_DIRENT_OBJ(-1ULL), buf);
+	    ZFS_DIRENT_OBJ(-1ULL), buf, buflen);
 	if (err != 0)
 		return (err);
 	err = zfs_zget(zfsvfs, parent, dzpp);
diff --git a/module/os/linux/zfs/zfs_dir.c b/module/os/linux/zfs/zfs_dir.c
index ad2ca15e2..f59281f06 100644
--- a/module/os/linux/zfs/zfs_dir.c
+++ b/module/os/linux/zfs/zfs_dir.c
@@ -847,6 +847,15 @@ zfs_link_create(zfs_dirlock_t *dl, znode_t *zp, dmu_tx_t *tx, int flag)
 		return (error);
 	}
 
+	/*
+	 * If we added a longname activate the SPA_FEATURE_LONGNAME.
+	 */
+	if (strlen(dl->dl_name) >= ZAP_MAXNAMELEN) {
+		dsl_dataset_t *ds = dmu_objset_ds(zfsvfs->z_os);
+		ds->ds_feature_activation[SPA_FEATURE_LONGNAME] =
+		    (void *)B_TRUE;
+	}
+
 	SA_ADD_BULK_ATTR(bulk, count, SA_ZPL_PARENT(zfsvfs), NULL,
 	    &dzp->z_id, sizeof (dzp->z_id));
 	SA_ADD_BULK_ATTR(bulk, count, SA_ZPL_FLAGS(zfsvfs), NULL,
diff --git a/module/os/linux/zfs/zfs_vfsops.c b/module/os/linux/zfs/zfs_vfsops.c
index a6d1202e4..a24f50412 100644
--- a/module/os/linux/zfs/zfs_vfsops.c
+++ b/module/os/linux/zfs/zfs_vfsops.c
@@ -57,6 +57,7 @@
 #include <sys/dmu_objset.h>
 #include <sys/dsl_dir.h>
 #include <sys/objlist.h>
+#include <sys/zfeature.h>
 #include <sys/zpl.h>
 #include <linux/vfs_compat.h>
 #include <linux/fs.h>
@@ -449,6 +450,12 @@ acl_inherit_changed_cb(void *arg, uint64_t newval)
 	((zfsvfs_t *)arg)->z_acl_inherit = newval;
 }
 
+static void
+longname_changed_cb(void *arg, uint64_t newval)
+{
+	((zfsvfs_t *)arg)->z_longname = newval;
+}
+
 static int
 zfs_register_callbacks(vfs_t *vfsp)
 {
@@ -509,6 +516,8 @@ zfs_register_callbacks(vfs_t *vfsp)
 	    zfsvfs);
 	error = error ? error : dsl_prop_register(ds,
 	    zfs_prop_to_name(ZFS_PROP_NBMAND), nbmand_changed_cb, zfsvfs);
+	error = error ? error : dsl_prop_register(ds,
+	    zfs_prop_to_name(ZFS_PROP_LONGNAME), longname_changed_cb, zfsvfs);
 	dsl_pool_config_exit(dmu_objset_pool(os), FTAG);
 	if (error)
 		goto unregister;
@@ -1140,7 +1149,8 @@ zfs_statvfs(struct inode *ip, struct kstatfs *statp)
 	statp->f_fsid.val[0] = (uint32_t)fsid;
 	statp->f_fsid.val[1] = (uint32_t)(fsid >> 32);
 	statp->f_type = ZFS_SUPER_MAGIC;
-	statp->f_namelen = MAXNAMELEN - 1;
+	statp->f_namelen =
+	    zfsvfs->z_longname ? (ZAP_MAXNAMELEN_NEW - 1) : (MAXNAMELEN - 1);
 
 	/*
 	 * We have all of 40 characters to stuff a string here.
diff --git a/module/os/linux/zfs/zfs_vnops_os.c b/module/os/linux/zfs/zfs_vnops_os.c
index 503b0d131..469197220 100644
--- a/module/os/linux/zfs/zfs_vnops_os.c
+++ b/module/os/linux/zfs/zfs_vnops_os.c
@@ -542,6 +542,46 @@ zfs_lookup(znode_t *zdp, char *nm, znode_t **zpp, int flags, cred_t *cr,
 	return (error);
 }
 
+/*
+ * Perform a linear search in directory for the name of specific inode.
+ * Note we don't pass in the buffer size of name because it's hardcoded to
+ * NAME_MAX+1(256) in Linux.
+ *
+ *	IN:	dzp	- znode of directory to search.
+ *		zp	- znode of the target
+ *
+ *	OUT:	name	- dentry name of the target
+ *
+ *	RETURN:	0 on success, error code on failure.
+ */
+int
+zfs_get_name(znode_t *dzp, char *name, znode_t *zp)
+{
+	zfsvfs_t *zfsvfs = ZTOZSB(dzp);
+	int error = 0;
+
+	if ((error = zfs_enter_verify_zp(zfsvfs, dzp, FTAG)) != 0)
+		return (error);
+
+	if ((error = zfs_verify_zp(zp)) != 0) {
+		zfs_exit(zfsvfs, FTAG);
+		return (error);
+	}
+
+	/* ctldir should have got their name in zfs_vget */
+	if (dzp->z_is_ctldir || zp->z_is_ctldir) {
+		zfs_exit(zfsvfs, FTAG);
+		return (ENOENT);
+	}
+
+	/* buffer len is hardcoded to 256 in Linux kernel */
+	error = zap_value_search(zfsvfs->z_os, dzp->z_id, zp->z_id,
+	    ZFS_DIRENT_OBJ(-1ULL), name, ZAP_MAXNAMELEN);
+
+	zfs_exit(zfsvfs, FTAG);
+	return (error);
+}
+
 /*
  * Attempt to create a new entry in a directory.  If the entry
  * already exists, truncate the file if permissible, else return
@@ -1548,7 +1588,7 @@ zfs_readdir(struct inode *ip, struct dir_context *ctx, cred_t *cr)
 	os = zfsvfs->z_os;
 	offset = ctx->pos;
 	prefetch = zp->z_zn_prefetch;
-	zap = zap_attribute_alloc();
+	zap = zap_attribute_long_alloc();
 
 	/*
 	 * Initialize the iterator cursor.
diff --git a/module/os/linux/zfs/zpl_export.c b/module/os/linux/zfs/zpl_export.c
index b6b9e2754..ff865d129 100644
--- a/module/os/linux/zfs/zpl_export.c
+++ b/module/os/linux/zfs/zpl_export.c
@@ -24,6 +24,7 @@
  */
 
 
+#include <sys/file.h>
 #include <sys/zfs_znode.h>
 #include <sys/zfs_vnops.h>
 #include <sys/zfs_ctldir.h>
@@ -102,6 +103,35 @@ zpl_fh_to_dentry(struct super_block *sb, struct fid *fh,
 	return (d_obtain_alias(ip));
 }
 
+/*
+ * In case the filesystem contains name longer than 255, we need to override
+ * the default get_name so we don't get buffer overflow. Unfortunately, since
+ * the buffer size is hardcoded in Linux, we will get ESTALE error in this
+ * case.
+ */
+static int
+zpl_get_name(struct dentry *parent, char *name, struct dentry *child)
+{
+	cred_t *cr = CRED();
+	fstrans_cookie_t cookie;
+	struct inode *dir = parent->d_inode;
+	struct inode *ip = child->d_inode;
+	int error;
+
+	if (!dir || !S_ISDIR(dir->i_mode))
+		return (-ENOTDIR);
+
+	crhold(cr);
+	cookie = spl_fstrans_mark();
+	spl_inode_lock_shared(dir);
+	error = -zfs_get_name(ITOZ(dir), name, ITOZ(ip));
+	spl_inode_unlock_shared(dir);
+	spl_fstrans_unmark(cookie);
+	crfree(cr);
+
+	return (error);
+}
+
 static struct dentry *
 zpl_get_parent(struct dentry *child)
 {
@@ -146,6 +176,7 @@ zpl_commit_metadata(struct inode *inode)
 const struct export_operations zpl_export_operations = {
 	.encode_fh		= zpl_encode_fh,
 	.fh_to_dentry		= zpl_fh_to_dentry,
+	.get_name		= zpl_get_name,
 	.get_parent		= zpl_get_parent,
 	.commit_metadata	= zpl_commit_metadata,
 };
diff --git a/module/os/linux/zfs/zpl_inode.c b/module/os/linux/zfs/zpl_inode.c
index 8386fc2ae..c4b5087ca 100644
--- a/module/os/linux/zfs/zpl_inode.c
+++ b/module/os/linux/zfs/zpl_inode.c
@@ -46,9 +46,29 @@ zpl_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
 	pathname_t pn;
 	int zfs_flags = 0;
 	zfsvfs_t *zfsvfs = dentry->d_sb->s_fs_info;
+	dsl_dataset_t *ds = dmu_objset_ds(zfsvfs->z_os);
+	size_t dlen = dlen(dentry);
 
-	if (dlen(dentry) >= ZAP_MAXNAMELEN)
+	/*
+	 * If z_longname is disabled, disallow create or rename of names
+	 * longer than ZAP_MAXNAMELEN.
+	 *
+	 * This is needed in cases where longname was enabled first and some
+	 * files/dirs with names > ZAP_MAXNAMELEN were created. And later
+	 * longname was disabled. In such a case allow access to existing
+	 * longnames. But disallow creation newer longnamed entities.
+	 */
+	if (!zfsvfs->z_longname && (dlen >= ZAP_MAXNAMELEN)) {
+		/*
+		 * If this is for create or rename fail it.
+		 */
+		if (!dsl_dataset_feature_is_active(ds, SPA_FEATURE_LONGNAME) ||
+		    (flags & (LOOKUP_CREATE | LOOKUP_RENAME_TARGET)))
+			return (ERR_PTR(-ENAMETOOLONG));
+	}
+	if (dlen >= ZAP_MAXNAMELEN_NEW) {
 		return (ERR_PTR(-ENAMETOOLONG));
+	}
 
 	crhold(cr);
 	cookie = spl_fstrans_mark();
@@ -131,6 +151,16 @@ zpl_vap_init(vattr_t *vap, struct inode *dir, umode_t mode, cred_t *cr,
 	}
 }
 
+static inline bool
+is_nametoolong(struct dentry *dentry)
+{
+	zfsvfs_t *zfsvfs = dentry->d_sb->s_fs_info;
+	size_t dlen = dlen(dentry);
+
+	return ((!zfsvfs->z_longname && dlen >= ZAP_MAXNAMELEN) ||
+	    dlen >= ZAP_MAXNAMELEN_NEW);
+}
+
 static int
 #ifdef HAVE_IOPS_CREATE_USERNS
 zpl_create(struct user_namespace *user_ns, struct inode *dir,
@@ -151,6 +181,10 @@ zpl_create(struct inode *dir, struct dentry *dentry, umode_t mode, bool flag)
 	zidmap_t *user_ns = kcred->user_ns;
 #endif
 
+	if (is_nametoolong(dentry)) {
+		return (-ENAMETOOLONG);
+	}
+
 	crhold(cr);
 	vap = kmem_zalloc(sizeof (vattr_t), KM_SLEEP);
 	zpl_vap_init(vap, dir, mode, cr, user_ns);
@@ -201,6 +235,10 @@ zpl_mknod(struct inode *dir, struct dentry *dentry, umode_t mode,
 	zidmap_t *user_ns = kcred->user_ns;
 #endif
 
+	if (is_nametoolong(dentry)) {
+		return (-ENAMETOOLONG);
+	}
+
 	/*
 	 * We currently expect Linux to supply rdev=0 for all sockets
 	 * and fifos, but we want to know if this behavior ever changes.
@@ -353,6 +391,10 @@ zpl_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
 	zidmap_t *user_ns = kcred->user_ns;
 #endif
 
+	if (is_nametoolong(dentry)) {
+		return (-ENAMETOOLONG);
+	}
+
 	crhold(cr);
 	vap = kmem_zalloc(sizeof (vattr_t), KM_SLEEP);
 	zpl_vap_init(vap, dir, mode | S_IFDIR, cr, user_ns);
@@ -568,6 +610,10 @@ zpl_rename2(struct inode *sdip, struct dentry *sdentry,
 	zidmap_t *user_ns = kcred->user_ns;
 #endif
 
+	if (is_nametoolong(tdentry)) {
+		return (-ENAMETOOLONG);
+	}
+
 	crhold(cr);
 	if (rflags & RENAME_WHITEOUT) {
 		wo_vap = kmem_zalloc(sizeof (vattr_t), KM_SLEEP);
@@ -618,6 +664,10 @@ zpl_symlink(struct inode *dir, struct dentry *dentry, const char *name)
 	zidmap_t *user_ns = kcred->user_ns;
 #endif
 
+	if (is_nametoolong(dentry)) {
+		return (-ENAMETOOLONG);
+	}
+
 	crhold(cr);
 	vap = kmem_zalloc(sizeof (vattr_t), KM_SLEEP);
 	zpl_vap_init(vap, dir, S_IFLNK | S_IRWXUGO, cr, user_ns);
@@ -707,6 +757,10 @@ zpl_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry)
 	int error;
 	fstrans_cookie_t cookie;
 
+	if (is_nametoolong(dentry)) {
+		return (-ENAMETOOLONG);
+	}
+
 	if (ip->i_nlink >= ZFS_LINK_MAX)
 		return (-EMLINK);
 
diff --git a/module/zcommon/zfeature_common.c b/module/zcommon/zfeature_common.c
index 8dec5f27b..881deb5bf 100644
--- a/module/zcommon/zfeature_common.c
+++ b/module/zcommon/zfeature_common.c
@@ -760,6 +760,18 @@ zpool_feature_init(void)
 	    ZFEATURE_FLAG_READONLY_COMPAT, ZFEATURE_TYPE_BOOLEAN, NULL,
 	    sfeatures);
 
+	{
+		static const spa_feature_t longname_deps[] = {
+			SPA_FEATURE_EXTENSIBLE_DATASET,
+			SPA_FEATURE_NONE
+		};
+		zfeature_register(SPA_FEATURE_LONGNAME,
+		    "org.zfsonlinux:longname", "longname",
+		    "support filename up to 1024 bytes",
+		    ZFEATURE_FLAG_PER_DATASET, ZFEATURE_TYPE_BOOLEAN,
+		    longname_deps, sfeatures);
+	}
+
 	zfs_mod_list_supported_free(sfeatures);
 }
 
diff --git a/module/zcommon/zfs_prop.c b/module/zcommon/zfs_prop.c
index 20cc0dffc..8179a1a8c 100644
--- a/module/zcommon/zfs_prop.c
+++ b/module/zcommon/zfs_prop.c
@@ -772,6 +772,10 @@ zfs_prop_init(void)
 	    ZFS_TYPE_VOLUME, "<date>", "SNAPSHOTS_CHANGED", B_FALSE, B_TRUE,
 	    B_TRUE, NULL, sfeatures);
 
+	zprop_register_index(ZFS_PROP_LONGNAME, "longname", 0, PROP_INHERIT,
+	    ZFS_TYPE_FILESYSTEM, "on | off", "LONGNAME", boolean_table,
+	    sfeatures);
+
 	zfs_mod_list_supported_free(sfeatures);
 }
 
diff --git a/module/zfs/dmu_recv.c b/module/zfs/dmu_recv.c
index 9b3da032f..4877eb7e6 100644
--- a/module/zfs/dmu_recv.c
+++ b/module/zfs/dmu_recv.c
@@ -602,6 +602,13 @@ recv_begin_check_feature_flags_impl(uint64_t featureflags, spa_t *spa)
 	    !spa_feature_is_enabled(spa, SPA_FEATURE_REDACTED_DATASETS))
 		return (SET_ERROR(ENOTSUP));
 
+	/*
+	 * If the LONGNAME is not enabled on the target, fail that request.
+	 */
+	if ((featureflags & DMU_BACKUP_FEATURE_LONGNAME) &&
+	    !spa_feature_is_enabled(spa, SPA_FEATURE_LONGNAME))
+		return (SET_ERROR(ENOTSUP));
+
 	return (0);
 }
 
@@ -990,6 +997,16 @@ dmu_recv_begin_sync(void *arg, dmu_tx_t *tx)
 	dmu_buf_will_dirty(newds->ds_dbuf, tx);
 	dsl_dataset_phys(newds)->ds_flags |= DS_FLAG_INCONSISTENT;
 
+	/*
+	 * Activate longname feature if received
+	 */
+	if (featureflags & DMU_BACKUP_FEATURE_LONGNAME &&
+	    !dsl_dataset_feature_is_active(newds, SPA_FEATURE_LONGNAME)) {
+		dsl_dataset_activate_feature(newds->ds_object,
+		    SPA_FEATURE_LONGNAME, (void *)B_TRUE, tx);
+		newds->ds_feature[SPA_FEATURE_LONGNAME] = (void *)B_TRUE;
+	}
+
 	/*
 	 * If we actually created a non-clone, we need to create the objset
 	 * in our new dataset. If this is a raw send we postpone this until
diff --git a/module/zfs/dmu_send.c b/module/zfs/dmu_send.c
index cb2b62fed..c7d3a5cb6 100644
--- a/module/zfs/dmu_send.c
+++ b/module/zfs/dmu_send.c
@@ -2011,6 +2011,10 @@ setup_featureflags(struct dmu_send_params *dspp, objset_t *os,
 	if (dsl_dataset_feature_is_active(to_ds, SPA_FEATURE_LARGE_DNODE)) {
 		*featureflags |= DMU_BACKUP_FEATURE_LARGE_DNODE;
 	}
+
+	if (dsl_dataset_feature_is_active(to_ds, SPA_FEATURE_LONGNAME)) {
+		*featureflags |= DMU_BACKUP_FEATURE_LONGNAME;
+	}
 	return (0);
 }
 
diff --git a/module/zfs/dsl_dataset.c b/module/zfs/dsl_dataset.c
index aa02af557..6a9ed8910 100644
--- a/module/zfs/dsl_dataset.c
+++ b/module/zfs/dsl_dataset.c
@@ -494,7 +494,8 @@ dsl_dataset_get_snapname(dsl_dataset_t *ds)
 		return (err);
 	headphys = headdbuf->db_data;
 	err = zap_value_search(dp->dp_meta_objset,
-	    headphys->ds_snapnames_zapobj, ds->ds_object, 0, ds->ds_snapname);
+	    headphys->ds_snapnames_zapobj, ds->ds_object, 0, ds->ds_snapname,
+	    sizeof (ds->ds_snapname));
 	if (err != 0 && zfs_recover == B_TRUE) {
 		err = 0;
 		(void) snprintf(ds->ds_snapname, sizeof (ds->ds_snapname),
diff --git a/module/zfs/dsl_dir.c b/module/zfs/dsl_dir.c
index 5aeff86b9..1b60fa620 100644
--- a/module/zfs/dsl_dir.c
+++ b/module/zfs/dsl_dir.c
@@ -239,7 +239,8 @@ dsl_dir_hold_obj(dsl_pool_t *dp, uint64_t ddobj,
 				err = zap_value_search(dp->dp_meta_objset,
 				    dsl_dir_phys(dd->dd_parent)->
 				    dd_child_dir_zapobj,
-				    ddobj, 0, dd->dd_myname);
+				    ddobj, 0, dd->dd_myname,
+				    sizeof (dd->dd_myname));
 			}
 			if (err != 0)
 				goto errout;
diff --git a/module/zfs/zap.c b/module/zfs/zap.c
index 603c76a2c..40e7bcf3e 100644
--- a/module/zfs/zap.c
+++ b/module/zfs/zap.c
@@ -832,7 +832,12 @@ zap_put_leaf_maybe_grow_ptrtbl(zap_name_t *zn, zap_leaf_t *l,
 static int
 fzap_checkname(zap_name_t *zn)
 {
-	if (zn->zn_key_orig_numints * zn->zn_key_intlen > ZAP_MAXNAMELEN)
+	uint32_t maxnamelen = zn->zn_normbuf_len;
+	uint64_t len = (uint64_t)zn->zn_key_orig_numints * zn->zn_key_intlen;
+	/* Only allow directory zap to have longname */
+	if (len > maxnamelen ||
+	    (len > ZAP_MAXNAMELEN &&
+	    zn->zn_zap->zap_dnode->dn_type != DMU_OT_DIRECTORY_CONTENTS))
 		return (SET_ERROR(ENAMETOOLONG));
 	return (0);
 }
@@ -1102,7 +1107,7 @@ zap_create_link_dnsize(objset_t *os, dmu_object_type_t ot, uint64_t parent_obj,
 
 int
 zap_value_search(objset_t *os, uint64_t zapobj, uint64_t value, uint64_t mask,
-    char *name)
+    char *name, uint64_t namelen)
 {
 	zap_cursor_t zc;
 	int err;
@@ -1110,12 +1115,13 @@ zap_value_search(objset_t *os, uint64_t zapobj, uint64_t value, uint64_t mask,
 	if (mask == 0)
 		mask = -1ULL;
 
-	zap_attribute_t *za = zap_attribute_alloc();
+	zap_attribute_t *za = zap_attribute_long_alloc();
 	for (zap_cursor_init(&zc, os, zapobj);
 	    (err = zap_cursor_retrieve(&zc, za)) == 0;
 	    zap_cursor_advance(&zc)) {
 		if ((za->za_first_integer & mask) == (value & mask)) {
-			(void) strlcpy(name, za->za_name, MAXNAMELEN);
+			if (strlcpy(name, za->za_name, namelen) >= namelen)
+				err = SET_ERROR(ENAMETOOLONG);
 			break;
 		}
 	}
@@ -1130,7 +1136,7 @@ zap_join(objset_t *os, uint64_t fromobj, uint64_t intoobj, dmu_tx_t *tx)
 	zap_cursor_t zc;
 	int err = 0;
 
-	zap_attribute_t *za = zap_attribute_alloc();
+	zap_attribute_t *za = zap_attribute_long_alloc();
 	for (zap_cursor_init(&zc, os, fromobj);
 	    zap_cursor_retrieve(&zc, za) == 0;
 	    (void) zap_cursor_advance(&zc)) {
@@ -1155,7 +1161,7 @@ zap_join_key(objset_t *os, uint64_t fromobj, uint64_t intoobj,
 	zap_cursor_t zc;
 	int err = 0;
 
-	zap_attribute_t *za = zap_attribute_alloc();
+	zap_attribute_t *za = zap_attribute_long_alloc();
 	for (zap_cursor_init(&zc, os, fromobj);
 	    zap_cursor_retrieve(&zc, za) == 0;
 	    (void) zap_cursor_advance(&zc)) {
@@ -1180,7 +1186,7 @@ zap_join_increment(objset_t *os, uint64_t fromobj, uint64_t intoobj,
 	zap_cursor_t zc;
 	int err = 0;
 
-	zap_attribute_t *za = zap_attribute_alloc();
+	zap_attribute_t *za = zap_attribute_long_alloc();
 	for (zap_cursor_init(&zc, os, fromobj);
 	    zap_cursor_retrieve(&zc, za) == 0;
 	    (void) zap_cursor_advance(&zc)) {
diff --git a/module/zfs/zap_micro.c b/module/zfs/zap_micro.c
index e52680dd4..a428a040a 100644
--- a/module/zfs/zap_micro.c
+++ b/module/zfs/zap_micro.c
@@ -131,12 +131,12 @@ zap_hash(zap_name_t *zn)
 }
 
 static int
-zap_normalize(zap_t *zap, const char *name, char *namenorm, int normflags)
+zap_normalize(zap_t *zap, const char *name, char *namenorm, int normflags,
+    size_t outlen)
 {
 	ASSERT(!(zap_getflags(zap) & ZAP_FLAG_UINT64_KEY));
 
 	size_t inlen = strlen(name) + 1;
-	size_t outlen = ZAP_MAXNAMELEN;
 
 	int err = 0;
 	(void) u8_textprep_str((char *)name, &inlen, namenorm, &outlen,
@@ -149,23 +149,39 @@ zap_normalize(zap_t *zap, const char *name, char *namenorm, int normflags)
 boolean_t
 zap_match(zap_name_t *zn, const char *matchname)
 {
+	boolean_t res = B_FALSE;
 	ASSERT(!(zap_getflags(zn->zn_zap) & ZAP_FLAG_UINT64_KEY));
 
 	if (zn->zn_matchtype & MT_NORMALIZE) {
-		char norm[ZAP_MAXNAMELEN];
+		size_t namelen = zn->zn_normbuf_len;
+		char normbuf[ZAP_MAXNAMELEN];
+		char *norm = normbuf;
+
+		/*
+		 * Cannot allocate this on-stack as it exceed the stack-limit of
+		 * 1024.
+		 */
+		if (namelen > ZAP_MAXNAMELEN)
+			norm = kmem_alloc(namelen, KM_SLEEP);
 
 		if (zap_normalize(zn->zn_zap, matchname, norm,
-		    zn->zn_normflags) != 0)
-			return (B_FALSE);
-
-		return (strcmp(zn->zn_key_norm, norm) == 0);
+		    zn->zn_normflags, namelen) != 0) {
+			res = B_FALSE;
+		} else {
+			res = (strcmp(zn->zn_key_norm, norm) == 0);
+		}
+		if (norm != normbuf)
+			kmem_free(norm, namelen);
 	} else {
-		return (strcmp(zn->zn_key_orig, matchname) == 0);
+		res = (strcmp(zn->zn_key_orig, matchname) == 0);
 	}
+	return (res);
 }
 
 static kmem_cache_t *zap_name_cache;
 static kmem_cache_t *zap_attr_cache;
+static kmem_cache_t *zap_name_long_cache;
+static kmem_cache_t *zap_attr_long_cache;
 
 void
 zap_init(void)
@@ -177,6 +193,14 @@ zap_init(void)
 	zap_attr_cache = kmem_cache_create("zap_attr_cache",
 	    sizeof (zap_attribute_t) + ZAP_MAXNAMELEN,  0, NULL,
 	    NULL, NULL, NULL, NULL, 0);
+
+	zap_name_long_cache = kmem_cache_create("zap_name_long",
+	    sizeof (zap_name_t) + ZAP_MAXNAMELEN_NEW, 0, NULL, NULL,
+	    NULL, NULL, NULL, 0);
+
+	zap_attr_long_cache = kmem_cache_create("zap_attr_long_cache",
+	    sizeof (zap_attribute_t) + ZAP_MAXNAMELEN_NEW,  0, NULL,
+	    NULL, NULL, NULL, NULL, 0);
 }
 
 void
@@ -184,33 +208,47 @@ zap_fini(void)
 {
 	kmem_cache_destroy(zap_name_cache);
 	kmem_cache_destroy(zap_attr_cache);
+	kmem_cache_destroy(zap_name_long_cache);
+	kmem_cache_destroy(zap_attr_long_cache);
 }
 
 static zap_name_t *
-zap_name_alloc(zap_t *zap)
+zap_name_alloc(zap_t *zap, boolean_t longname)
 {
-	zap_name_t *zn = kmem_cache_alloc(zap_name_cache, KM_SLEEP);
+	kmem_cache_t *cache = longname ? zap_name_long_cache : zap_name_cache;
+	zap_name_t *zn = kmem_cache_alloc(cache, KM_SLEEP);
+
 	zn->zn_zap = zap;
+	zn->zn_normbuf_len = longname ? ZAP_MAXNAMELEN_NEW : ZAP_MAXNAMELEN;
 	return (zn);
 }
 
 void
 zap_name_free(zap_name_t *zn)
 {
-	kmem_cache_free(zap_name_cache, zn);
+	if (zn->zn_normbuf_len == ZAP_MAXNAMELEN) {
+		kmem_cache_free(zap_name_cache, zn);
+	} else {
+		ASSERT3U(zn->zn_normbuf_len, ==, ZAP_MAXNAMELEN_NEW);
+		kmem_cache_free(zap_name_long_cache, zn);
+	}
 }
 
 static int
 zap_name_init_str(zap_name_t *zn, const char *key, matchtype_t mt)
 {
 	zap_t *zap = zn->zn_zap;
+	size_t key_len = strlen(key) + 1;
+
+	/* Make sure zn is allocated for longname if key is long */
+	IMPLY(key_len > ZAP_MAXNAMELEN,
+	    zn->zn_normbuf_len == ZAP_MAXNAMELEN_NEW);
 
 	zn->zn_key_intlen = sizeof (*key);
 	zn->zn_key_orig = key;
-	zn->zn_key_orig_numints = strlen(zn->zn_key_orig) + 1;
+	zn->zn_key_orig_numints = key_len;
 	zn->zn_matchtype = mt;
 	zn->zn_normflags = zap->zap_normflags;
-	zn->zn_normbuf_len = ZAP_MAXNAMELEN;
 
 	/*
 	 * If we're dealing with a case sensitive lookup on a mixed or
@@ -226,7 +264,7 @@ zap_name_init_str(zap_name_t *zn, const char *key, matchtype_t mt)
 		 * what the hash is computed from.
 		 */
 		if (zap_normalize(zap, key, zn->zn_normbuf,
-		    zap->zap_normflags) != 0)
+		    zap->zap_normflags, zn->zn_normbuf_len) != 0)
 			return (SET_ERROR(ENOTSUP));
 		zn->zn_key_norm = zn->zn_normbuf;
 		zn->zn_key_norm_numints = strlen(zn->zn_key_norm) + 1;
@@ -245,7 +283,7 @@ zap_name_init_str(zap_name_t *zn, const char *key, matchtype_t mt)
 		 * what the matching is based on.  (Not the hash!)
 		 */
 		if (zap_normalize(zap, key, zn->zn_normbuf,
-		    zn->zn_normflags) != 0)
+		    zn->zn_normflags, zn->zn_normbuf_len) != 0)
 			return (SET_ERROR(ENOTSUP));
 		zn->zn_key_norm_numints = strlen(zn->zn_key_norm) + 1;
 	}
@@ -256,7 +294,8 @@ zap_name_init_str(zap_name_t *zn, const char *key, matchtype_t mt)
 zap_name_t *
 zap_name_alloc_str(zap_t *zap, const char *key, matchtype_t mt)
 {
-	zap_name_t *zn = zap_name_alloc(zap);
+	size_t key_len = strlen(key) + 1;
+	zap_name_t *zn = zap_name_alloc(zap, (key_len > ZAP_MAXNAMELEN));
 	if (zap_name_init_str(zn, key, mt) != 0) {
 		zap_name_free(zn);
 		return (NULL);
@@ -491,7 +530,7 @@ mzap_open(dmu_buf_t *db)
 		zfs_btree_create_custom(&zap->zap_m.zap_tree, mze_compare,
 		    mze_find_in_buf, sizeof (mzap_ent_t), 512);
 
-		zap_name_t *zn = zap_name_alloc(zap);
+		zap_name_t *zn = zap_name_alloc(zap, B_FALSE);
 		for (uint16_t i = 0; i < zap->zap_m.zap_num_chunks; i++) {
 			mzap_ent_phys_t *mze =
 			    &zap_m_phys(zap)->mz_chunk[i];
@@ -698,7 +737,7 @@ mzap_upgrade(zap_t **zapp, const void *tag, dmu_tx_t *tx, zap_flags_t flags)
 
 	fzap_upgrade(zap, tx, flags);
 
-	zap_name_t *zn = zap_name_alloc(zap);
+	zap_name_t *zn = zap_name_alloc(zap, B_FALSE);
 	for (int i = 0; i < nchunks; i++) {
 		mzap_ent_phys_t *mze = &mzp->mz_chunk[i];
 		if (mze->mze_name[0] == 0)
@@ -1625,21 +1664,38 @@ zap_remove_uint64_by_dnode(dnode_t *dn, const uint64_t *key, int key_numints,
 }
 
 
+static zap_attribute_t *
+zap_attribute_alloc_impl(boolean_t longname)
+{
+	zap_attribute_t *za;
+
+	za = kmem_cache_alloc((longname)? zap_attr_long_cache : zap_attr_cache,
+	    KM_SLEEP);
+	za->za_name_len = (longname)? ZAP_MAXNAMELEN_NEW : ZAP_MAXNAMELEN;
+	return (za);
+}
+
 zap_attribute_t *
 zap_attribute_alloc(void)
 {
-	uint32_t len = ZAP_MAXNAMELEN;
-	zap_attribute_t *za;
+	return (zap_attribute_alloc_impl(B_FALSE));
+}
 
-	za = kmem_cache_alloc(zap_attr_cache, KM_SLEEP);
-	za->za_name_len = len;
-	return (za);
+zap_attribute_t *
+zap_attribute_long_alloc(void)
+{
+	return (zap_attribute_alloc_impl(B_TRUE));
 }
 
 void
 zap_attribute_free(zap_attribute_t *za)
 {
-	kmem_cache_free(zap_attr_cache, za);
+	if (za->za_name_len == ZAP_MAXNAMELEN) {
+		kmem_cache_free(zap_attr_cache, za);
+	} else {
+		ASSERT3U(za->za_name_len, ==, ZAP_MAXNAMELEN_NEW);
+		kmem_cache_free(zap_attr_long_cache, za);
+	}
 }
 
 /*
diff --git a/module/zfs/zfs_ioctl.c b/module/zfs/zfs_ioctl.c
index e69b98896..8188a9e46 100644
--- a/module/zfs/zfs_ioctl.c
+++ b/module/zfs/zfs_ioctl.c
@@ -2594,6 +2594,41 @@ zfs_prop_set_special(const char *dsname, zprop_source_t source,
 		}
 		break;
 	}
+	case ZFS_PROP_LONGNAME:
+	{
+		zfsvfs_t *zfsvfs;
+
+		/*
+		 * Ignore the checks if the property is being applied as part of
+		 * 'zfs receive'. Because, we already check if the local pool
+		 * has SPA_FEATURE_LONGNAME enabled in dmu_recv_begin_check().
+		 */
+		if (source == ZPROP_SRC_RECEIVED) {
+			cmn_err(CE_NOTE, "Skipping ZFS_PROP_LONGNAME checks "
+			    "for dsname=%s\n", dsname);
+			err = -1;
+			break;
+		}
+
+		if ((err = zfsvfs_hold(dsname, FTAG, &zfsvfs, B_FALSE)) != 0) {
+			cmn_err(CE_WARN, "%s:%d Failed to hold for dsname=%s "
+			    "err=%d\n", __FILE__, __LINE__, dsname, err);
+			break;
+		}
+
+		if (!spa_feature_is_enabled(zfsvfs->z_os->os_spa,
+		    SPA_FEATURE_LONGNAME)) {
+			err = ENOTSUP;
+		} else {
+			/*
+			 * Set err to -1 to force the zfs_set_prop_nvlist code
+			 * down the default path to set the value in the nvlist.
+			 */
+			err = -1;
+		}
+		zfsvfs_rele(zfsvfs, FTAG);
+		break;
+	}
 	default:
 		err = -1;
 	}
diff --git a/module/zfs/zfs_znode.c b/module/zfs/zfs_znode.c
index 2e28587c8..824db8c68 100644
--- a/module/zfs/zfs_znode.c
+++ b/module/zfs/zfs_znode.c
@@ -178,6 +178,7 @@ zfs_obj_to_path_impl(objset_t *osp, uint64_t obj, sa_handle_t *hdl,
 	dmu_buf_t *prevdb = NULL;
 	dmu_buf_t *sa_db = NULL;
 	char *path = buf + len - 1;
+	char *comp_buf;
 	int error;
 
 	*path = '\0';
@@ -193,9 +194,10 @@ zfs_obj_to_path_impl(objset_t *osp, uint64_t obj, sa_handle_t *hdl,
 		return (error);
 	}
 
+	comp_buf = kmem_alloc(ZAP_MAXNAMELEN_NEW + 2, KM_SLEEP);
 	for (;;) {
 		uint64_t pobj = 0;
-		char component[MAXNAMELEN + 2];
+		char *component = comp_buf;
 		size_t complen;
 		int is_xattrdir = 0;
 
@@ -219,7 +221,8 @@ zfs_obj_to_path_impl(objset_t *osp, uint64_t obj, sa_handle_t *hdl,
 			strcpy(component + 1, "<xattrdir>");
 		} else {
 			error = zap_value_search(osp, pobj, obj,
-			    ZFS_DIRENT_OBJ(-1ULL), component + 1);
+			    ZFS_DIRENT_OBJ(-1ULL), component + 1,
+			    ZAP_MAXNAMELEN_NEW);
 			if (error != 0)
 				break;
 		}
@@ -250,6 +253,7 @@ zfs_obj_to_path_impl(objset_t *osp, uint64_t obj, sa_handle_t *hdl,
 	if (error == 0)
 		(void) memmove(buf, path, buf + len - path);
 
+	kmem_free(comp_buf, ZAP_MAXNAMELEN_NEW +2);
 	return (error);
 }
 
diff --git a/tests/runfiles/linux.run b/tests/runfiles/linux.run
index 4e262affb..5534cd27f 100644
--- a/tests/runfiles/linux.run
+++ b/tests/runfiles/linux.run
@@ -143,6 +143,10 @@ pre =
 post =
 tags = ['functional', 'largest_pool']
 
+[tests/functional/longname:Linux]
+tests = ['longname_001_pos', 'longname_002_pos', 'longname_003_pos']
+tags = ['functional', 'longname']
+
 [tests/functional/mmap:Linux]
 tests = ['mmap_libaio_001_pos', 'mmap_sync_001_pos']
 tags = ['functional', 'mmap']
@@ -187,7 +191,7 @@ tests = ['renameat2_noreplace', 'renameat2_exchange', 'renameat2_whiteout']
 tags = ['functional', 'renameat2']
 
 [tests/functional/rsend:Linux]
-tests = ['send_realloc_dnode_size', 'send_encrypted_files']
+tests = ['send_realloc_dnode_size', 'send_encrypted_files', 'send-c_longname']
 tags = ['functional', 'rsend']
 
 [tests/functional/simd:Linux]
diff --git a/tests/zfs-tests/tests/Makefile.am b/tests/zfs-tests/tests/Makefile.am
index da6dc235c..206ee8ac1 100644
--- a/tests/zfs-tests/tests/Makefile.am
+++ b/tests/zfs-tests/tests/Makefile.am
@@ -1605,6 +1605,11 @@ nobase_dist_datadir_zfs_tests_tests_SCRIPTS += \
 	functional/link_count/link_count_001.ksh \
 	functional/link_count/link_count_root_inode.ksh \
 	functional/link_count/setup.ksh \
+	functional/longname/cleanup.ksh \
+	functional/longname/longname_001_pos.ksh \
+	functional/longname/longname_002_pos.ksh \
+	functional/longname/longname_003_pos.ksh \
+	functional/longname/setup.ksh \
 	functional/log_spacemap/log_spacemap_import_logs.ksh \
 	functional/migration/cleanup.ksh \
 	functional/migration/migration_001_pos.ksh \
@@ -1938,6 +1943,7 @@ nobase_dist_datadir_zfs_tests_tests_SCRIPTS += \
 	functional/rsend/rsend_031_pos.ksh \
 	functional/rsend/send-c_embedded_blocks.ksh \
 	functional/rsend/send-c_incremental.ksh \
+	functional/rsend/send-c_longname.ksh \
 	functional/rsend/send-c_lz4_disabled.ksh \
 	functional/rsend/send-c_mixed_compression.ksh \
 	functional/rsend/send-c_props.ksh \
diff --git a/tests/zfs-tests/tests/functional/cli_root/zpool_get/zpool_get.cfg b/tests/zfs-tests/tests/functional/cli_root/zpool_get/zpool_get.cfg
index 50c1b7a9d..b5bc46dce 100644
--- a/tests/zfs-tests/tests/functional/cli_root/zpool_get/zpool_get.cfg
+++ b/tests/zfs-tests/tests/functional/cli_root/zpool_get/zpool_get.cfg
@@ -110,5 +110,6 @@ if is_linux || is_freebsd; then
 	    "feature@vdev_zaps_v2"
 	    "feature@raidz_expansion"
 	    "feature@fast_dedup"
+	    "feature@longname"
 	)
 fi
diff --git a/tests/zfs-tests/tests/functional/longname/cleanup.ksh b/tests/zfs-tests/tests/functional/longname/cleanup.ksh
new file mode 100755
index 000000000..aac8062ec
--- /dev/null
+++ b/tests/zfs-tests/tests/functional/longname/cleanup.ksh
@@ -0,0 +1,34 @@
+#!/bin/ksh -p
+#
+# CDDL HEADER START
+#
+# The contents of this file are subject to the terms of the
+# Common Development and Distribution License (the "License").
+# You may not use this file except in compliance with the License.
+#
+# You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+# or http://www.opensolaris.org/os/licensing.
+# See the License for the specific language governing permissions
+# and limitations under the License.
+#
+# When distributing Covered Code, include this CDDL HEADER in each
+# file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+# If applicable, add the following below this CDDL HEADER, with the
+# fields enclosed by brackets "[]" replaced with your own identifying
+# information: Portions Copyright [yyyy] [name of copyright owner]
+#
+# CDDL HEADER END
+#
+
+#
+# Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
+# Use is subject to license terms.
+#
+
+#
+# Copyright (c) 2021 by Nutanix. All rights reserved.
+#
+
+. $STF_SUITE/include/libtest.shlib
+
+default_cleanup
diff --git a/tests/zfs-tests/tests/functional/longname/longname_001_pos.ksh b/tests/zfs-tests/tests/functional/longname/longname_001_pos.ksh
new file mode 100755
index 000000000..b7010fe0f
--- /dev/null
+++ b/tests/zfs-tests/tests/functional/longname/longname_001_pos.ksh
@@ -0,0 +1,132 @@
+#! /bin/ksh -p
+#
+# CDDL HEADER START
+#
+# The contents of this file are subject to the terms of the
+# Common Development and Distribution License (the "License").
+# You may not use this file except in compliance with the License.
+#
+# You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+# or http://www.opensolaris.org/os/licensing.
+# See the License for the specific language governing permissions
+# and limitations under the License.
+#
+# When distributing Covered Code, include this CDDL HEADER in each
+# file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+# If applicable, add the following below this CDDL HEADER, with the
+# fields enclosed by brackets "[]" replaced with your own identifying
+# information: Portions Copyright [yyyy] [name of copyright owner]
+#
+# CDDL HEADER END
+#
+
+#
+# Copyright (c) 2021 by Nutanix. All rights reserved.
+#
+
+. $STF_SUITE/include/libtest.shlib
+
+#
+# DESCRIPTION:
+# Verify the support for long filenames.
+#
+# STRATEGY:
+# 0.  On a fresh dataset ensure property "longname" is enabled by default.
+# 1.  Disable the longname.
+# 2.  Try to create a filename whose length is > 256 bytes. This should fail.
+# 3.  Enable "longname" property on the dataset.
+# 4.  Try to create files and dirs whose names are > 256 bytes.
+# 5.  Ensure that "ls" is able to list the file.
+# 6.  Ensure stat(1) is able to stat the file/directory.
+# 7.  Try to rename the files and directories
+# 8.  Try to delete the files and directories
+
+verify_runnable "global"
+
+WORKDIR=$TESTDIR/workdir
+MOVEDIR=$TESTDIR/movedir/level2/level3/level4/level5/level6
+
+function cleanup
+{
+        log_must rm -rf $WORKDIR
+        log_must rm -rf $TESTDIR/movedir
+}
+
+LONGNAME=$(printf 'a%.0s' {1..512})
+LONGFNAME="file-$LONGNAME"
+LONGDNAME="dir-$LONGNAME"
+LONGPNAME="mypipe-$LONGNAME"
+LONGCNAME="char_dev-$LONGNAME"
+LONGLNAME="link-$LONGNAME"
+LONGNAME_255=$(printf 'a%.0s' {1..255})
+LONGNAME_1023=$(printf 'a%.0s' {1..1023})
+
+
+log_assert "Check longname support for directories/files"
+
+log_onexit cleanup
+
+log_must mkdir $WORKDIR
+log_must mkdir -p $MOVEDIR
+
+# Disable longname support
+log_must zfs set longname=off $TESTPOOL/$TESTFS
+
+#Ensure a file of length 255bytes can be created
+log_must touch $WORKDIR/$LONGNAME_255
+
+#Where as file of length 256bytes should fail
+log_mustnot touch $WORKDIR/${LONGNAME_255}b
+
+# Try to create a file with long name with property "longname=off"
+log_mustnot touch $WORKDIR/$LONGFNAME
+log_mustnot mkdir $WORKDIR/$LONGDNAME
+
+# Enable longname support
+log_must zfs set longname=on $TESTPOOL/$TESTFS
+
+# Retry the longname creates and that should succeed
+log_must mkdir $WORKDIR/$LONGDNAME
+log_must touch $WORKDIR/$LONGFNAME
+
+# Should be able to create a file with name of 1023 chars
+log_must touch $WORKDIR/$LONGNAME_1023
+
+# And names longer that 1023 should fail
+log_mustnot touch $WORKDIR/${LONGNAME_1023}b
+
+# Ensure the longnamed dir/file can be listed.
+name=$(ls $WORKDIR/$LONGFNAME)
+if [[ "${name}" != "$WORKDIR/$LONGFNAME" ]]; then
+        log_fail "Unable to list: $WORKDIR/$LONGFNAME ret:$name"
+fi
+
+name=$(ls -d $WORKDIR/$LONGDNAME)
+if [[ "${name}" != "$WORKDIR/$LONGDNAME" ]]; then
+        log_fail "Unable to list: $WORKDIR/$LONGDNAME ret:$name"
+fi
+
+# Ensure stat works
+log_must stat $WORKDIR/$LONGFNAME
+log_must stat $WORKDIR/$LONGDNAME
+
+# Ensure softlinks can be created from a longname to
+# another longnamed file.
+log_must ln -s $WORKDIR/$LONGFNAME $WORKDIR/$LONGLNAME
+
+# Ensure a longnamed pipe and character device file
+# can be created
+log_must mknod $WORKDIR/$LONGPNAME p
+log_must mknod $WORKDIR/$LONGCNAME c 92 1
+
+# Ensure we can rename the longname file
+log_must mv $WORKDIR/$LONGFNAME $WORKDIR/file2
+
+# Delete the long named dir/file
+log_must rmdir $WORKDIR/$LONGDNAME
+log_must rm $WORKDIR/file2
+log_must rm $WORKDIR/$LONGPNAME
+log_must rm $WORKDIR/$LONGCNAME
+log_must rm $WORKDIR/$LONGLNAME
+
+log_pass
diff --git a/tests/zfs-tests/tests/functional/longname/longname_002_pos.ksh b/tests/zfs-tests/tests/functional/longname/longname_002_pos.ksh
new file mode 100755
index 000000000..dd2acabb3
--- /dev/null
+++ b/tests/zfs-tests/tests/functional/longname/longname_002_pos.ksh
@@ -0,0 +1,115 @@
+#! /bin/ksh -p
+#
+# CDDL HEADER START
+#
+# The contents of this file are subject to the terms of the
+# Common Development and Distribution License (the "License").
+# You may not use this file except in compliance with the License.
+#
+# You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+# or http://www.opensolaris.org/os/licensing.
+# See the License for the specific language governing permissions
+# and limitations under the License.
+#
+# When distributing Covered Code, include this CDDL HEADER in each
+# file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+# If applicable, add the following below this CDDL HEADER, with the
+# fields enclosed by brackets "[]" replaced with your own identifying
+# information: Portions Copyright [yyyy] [name of copyright owner]
+#
+# CDDL HEADER END
+#
+
+#
+# Copyright (c) 2021 by Nutanix. All rights reserved.
+#
+
+. $STF_SUITE/include/libtest.shlib
+
+#
+# DESCRIPTION:
+# Check if longname feature is disabled by default and can be enabled.
+#
+# STRATEGY:
+# 1. Create a zpool with longname feature disabled
+# 2. Attempt to enable 'longname' property should fail.
+# 3. Attempt to create a longnamed (>255) file should fail.
+# 4. Enable the feature@longname
+# 5. Enable 'longname' property on the dataset.
+# 6. Should be able to create long named files and directories.
+# 7. Should be able to disable longname property.
+# 8. This should disallow creating new longnamed file/dirs. But, should be
+#    able to access existing longnamed files/dirs.
+verify_runnable "global"
+
+function cleanup
+{
+        log_must rm -rf $WORKDIR
+        poolexists $TESTPOOL && zpool destroy $TESTPOOL
+}
+
+log_assert "Check feature@longname and 'longname' dataset propery work correctly"
+
+log_onexit cleanup
+
+log_must zpool destroy $TESTPOOL
+
+log_must zpool create -o feature@longname=disabled $TESTPOOL $DISKS
+
+log_must zfs create $TESTPOOL/$TESTFS2
+
+log_must zfs set mountpoint=$TESTDIR2 $TESTPOOL/$TESTFS2
+
+log_mustnot zfs set longname=on $TESTPOOL/$TESTFS2
+
+LONGNAME=$(printf 'a%.0s' {1..512})
+LONGFNAME="file-$LONGNAME"
+LONGDNAME="dir-$LONGNAME"
+SHORTDNAME="dir-short"
+SHORTFNAME="file-short"
+WORKDIR=$TESTDIR2/workdir
+
+log_must mkdir $WORKDIR
+log_mustnot touch $WORKDIR/$LONGFNAME
+log_mustnot mkdir $WORKDIR/$LONGDNAME
+
+log_must zpool set feature@longname=enabled $TESTPOOL
+log_must zfs set longname=on $TESTPOOL/$TESTFS2
+
+log_must mkdir $WORKDIR/$LONGDNAME
+log_must touch $WORKDIR/$LONGFNAME
+
+# Ensure the above changes are synced out.
+log_must zpool sync $TESTPOOL
+
+# Ensure that the feature is activated once longnamed files are created.
+state=$(zpool get feature@longname -H -o value $TESTPOOL)
+log_note "feature@longname on pool: $TESTPOOL : $state"
+
+if [[ "$state" != "active" ]]; then
+	log_fail "feature@longname has state $state (expected active)"
+fi
+
+# Set longname=off.
+log_must zfs set longname=off $TESTPOOL/$TESTFS2
+
+# Ensure no new file/directory with longnames can be created or can be renamed
+# to.
+log_mustnot mkdir $WORKDIR/${LONGDNAME}.1
+log_mustnot touch $WORKDIR/${LONGFNAME}.1
+log_must mkdir $WORKDIR/$SHORTDNAME
+log_mustnot mv $WORKDIR/$SHORTDNAME $WORKDIR/${LONGDNAME}.1
+log_must touch $WORKDIR/$SHORTFNAME
+log_mustnot mv $WORKDIR/$SHORTFNAME $WORKDIR/${LONGFNAME}.1
+
+#Cleanup shortnames
+log_must rmdir $WORKDIR/$SHORTDNAME
+log_must rm $WORKDIR/$SHORTFNAME
+
+# But, should be able to stat and rename existing files
+log_must stat $WORKDIR/$LONGDNAME
+log_must stat $WORKDIR/$LONGFNAME
+log_must mv $WORKDIR/$LONGDNAME $WORKDIR/$SHORTDNAME
+log_must mv $WORKDIR/$LONGFNAME $WORKDIR/$SHORTFNAME
+
+log_pass
diff --git a/tests/zfs-tests/tests/functional/longname/longname_003_pos.ksh b/tests/zfs-tests/tests/functional/longname/longname_003_pos.ksh
new file mode 100755
index 000000000..f684b5143
--- /dev/null
+++ b/tests/zfs-tests/tests/functional/longname/longname_003_pos.ksh
@@ -0,0 +1,113 @@
+#! /bin/ksh -p
+#
+# CDDL HEADER START
+#
+# The contents of this file are subject to the terms of the
+# Common Development and Distribution License (the "License").
+# You may not use this file except in compliance with the License.
+#
+# You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+# or http://www.opensolaris.org/os/licensing.
+# See the License for the specific language governing permissions
+# and limitations under the License.
+#
+# When distributing Covered Code, include this CDDL HEADER in each
+# file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+# If applicable, add the following below this CDDL HEADER, with the
+# fields enclosed by brackets "[]" replaced with your own identifying
+# information: Portions Copyright [yyyy] [name of copyright owner]
+#
+# CDDL HEADER END
+#
+
+#
+# Copyright (c) 2021 by Nutanix. All rights reserved.
+#
+
+. $STF_SUITE/include/libtest.shlib
+
+#
+# DESCRIPTION:
+# Check if longnames are handled correctly by ZIL replay and feature is activated.
+#
+# STRATEGY:
+# 1. Create a zpool with longname feature disabled
+# 2. Enable the feature@longname
+# 3. Enable 'longname' property on the dataset.
+# 4. Freeze the zpool
+# 5. Create a longname
+# 6. Export and import the zpool.
+# 7. Replaying of longname create should activate the feature@longname
+verify_runnable "global"
+
+function cleanup
+{
+	log_must rm -rf $WORKDIR
+	poolexists $TESTPOOL && zpool destroy $TESTPOOL
+}
+
+log_assert "Check feature@longname and 'longname' dataset propery work correctly"
+
+log_onexit cleanup
+
+poolexists $TESTPOOL && zpool destroy $TESTPOOL
+
+log_must zpool create -o feature@longname=disabled $TESTPOOL $DISKS
+
+log_must zfs create $TESTPOOL/$TESTFS
+
+log_must zfs set mountpoint=$TESTDIR $TESTPOOL/$TESTFS
+
+LONGNAME=$(printf 'a%.0s' {1..512})
+LONGFNAME="file-$LONGNAME"
+LONGDNAME="dir-$LONGNAME"
+SHORTDNAME="dir-short"
+SHORTFNAME="file-short"
+WORKDIR=$TESTDIR/workdir
+
+log_must mkdir $WORKDIR
+
+log_must zpool set feature@longname=enabled $TESTPOOL
+log_must zfs set longname=on $TESTPOOL/$TESTFS
+
+# Ensure that the feature is NOT activated yet as no longnamed file is created.
+state=$(zpool get feature@longname -H -o value $TESTPOOL)
+log_note "feature@longname on pool: $TESTPOOL : $state"
+
+if [[ "$state" != "enabled" ]]; then
+	log_fail "feature@longname has state $state (expected enabled)"
+fi
+
+#
+# This dd command works around an issue where ZIL records aren't created
+# after freezing the pool unless a ZIL header already exists. Create a file
+# synchronously to force ZFS to write one out.
+#
+log_must dd if=/dev/zero of=/$WORKDIR/sync conv=fdatasync,fsync bs=1 count=1
+
+log_must zpool freeze $TESTPOOL
+
+log_must mkdir $WORKDIR/$LONGDNAME
+log_must touch $WORKDIR/$LONGFNAME
+
+# Export and re-import the zpool
+log_must zpool export $TESTPOOL
+log_must zpool import $TESTPOOL
+
+# Ensure that the feature is activated once longnamed files are created.
+state=$(zpool get feature@longname -H -o value $TESTPOOL)
+log_note "feature@longname on pool: $TESTPOOL : $state"
+if [[ "$state" != "active" ]]; then
+	log_fail "feature@longname has state $state (expected active)"
+fi
+
+# Destroying the dataset where the feature is activated should put the feature
+# back to 'enabled' state
+log_must zfs destroy -r $TESTPOOL/$TESTFS
+state=$(zpool get feature@longname -H -o value $TESTPOOL)
+log_note "feature@longname on pool: $TESTPOOL : $state"
+if [[ "$state" != "enabled" ]]; then
+	log_fail "feature@longname has state $state (expected active)"
+fi
+
+log_pass
diff --git a/tests/zfs-tests/tests/functional/longname/setup.ksh b/tests/zfs-tests/tests/functional/longname/setup.ksh
new file mode 100755
index 000000000..3f6759469
--- /dev/null
+++ b/tests/zfs-tests/tests/functional/longname/setup.ksh
@@ -0,0 +1,35 @@
+#!/bin/ksh -p
+#
+# CDDL HEADER START
+#
+# The contents of this file are subject to the terms of the
+# Common Development and Distribution License (the "License").
+# You may not use this file except in compliance with the License.
+#
+# You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+# or http://www.opensolaris.org/os/licensing.
+# See the License for the specific language governing permissions
+# and limitations under the License.
+#
+# When distributing Covered Code, include this CDDL HEADER in each
+# file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+# If applicable, add the following below this CDDL HEADER, with the
+# fields enclosed by brackets "[]" replaced with your own identifying
+# information: Portions Copyright [yyyy] [name of copyright owner]
+#
+# CDDL HEADER END
+#
+
+#
+# Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
+# Use is subject to license terms.
+#
+
+#
+# Copyright (c) 2021 by Nutanix. All rights reserved.
+#
+
+. $STF_SUITE/include/libtest.shlib
+
+DISK=${DISKS%% *}
+default_setup $DISK
diff --git a/tests/zfs-tests/tests/functional/rsend/rsend.kshlib b/tests/zfs-tests/tests/functional/rsend/rsend.kshlib
index 8f2222dce..b4fcdd7bb 100644
--- a/tests/zfs-tests/tests/functional/rsend/rsend.kshlib
+++ b/tests/zfs-tests/tests/functional/rsend/rsend.kshlib
@@ -713,6 +713,7 @@ function stream_has_features
 	feature[resuming]="100000"
 	feature[redacted]="200000"
 	feature[compressed]="400000"
+	feature[longname]="10000000"
 
 	typeset flag known derived=0
 	for flag in "$@"; do
diff --git a/tests/zfs-tests/tests/functional/rsend/send-c_longname.ksh b/tests/zfs-tests/tests/functional/rsend/send-c_longname.ksh
new file mode 100755
index 000000000..3f7edc681
--- /dev/null
+++ b/tests/zfs-tests/tests/functional/rsend/send-c_longname.ksh
@@ -0,0 +1,98 @@
+#!/bin/ksh -p
+
+#
+# This file and its contents are supplied under the terms of the
+# Common Development and Distribution License ("CDDL"), version 1.0.
+# You may only use this file in accordance with the terms of version
+# 1.0 of the CDDL.
+#
+# A full copy of the text of the CDDL should have accompanied this
+# source.  A copy of the CDDL is also available via the Internet at
+# http://www.illumos.org/license/CDDL.
+#
+
+#
+# Copyright (c) 2021 by Nutanix. All rights reserved.
+#
+
+. $STF_SUITE/tests/functional/rsend/rsend.kshlib
+. $STF_SUITE/include/properties.shlib
+
+#
+# Description:
+# Verify that longname featureflag is present in the stream.
+#
+# Strategy:
+# 1. Create a filesystem with longnamed files/directories.
+# 2. Verify that the sendstream has the longname featureflag is present in the
+#    send stream.
+# 3. Verify the created streams can be received correctly.
+# 4. Verify that the longnamed files/directories are present in the received
+#    filesystem.
+#
+
+verify_runnable "both"
+
+log_assert "Verify that longnames are handled correctly in send stream."
+log_onexit cleanup_pool $POOL $POOL2 $POOL3
+
+typeset sendfs=$POOL/sendfs
+typeset recvfs=$POOL2/recvfs
+typeset recvfs3=$POOL3/recvfs
+typeset stream=$BACKDIR/stream
+typeset dump=$BACKDIR/dump
+
+log_must zfs create -o longname=on $sendfs
+typeset dir=$(get_prop mountpoint $sendfs)
+
+# Create a longnamed dir and a file in the send dataset
+LONGNAME=$(printf 'a%.0s' {1..512})
+LONGFNAME="file-$LONGNAME"
+LONGDNAME="dir-$LONGNAME"
+log_must mkdir $dir/$LONGDNAME
+log_must touch $dir/$LONGFNAME
+
+# When POOL3 is created by rsend.kshlib feature@longname is 'enabled'.
+# Recreate the POOL3 with feature@longname disabled.
+datasetexists $POOL3 && log_must zpool destroy $POOL3
+log_must zpool create -o feature@longname=disabled $POOL3 $DISK3
+
+# Generate the streams and zstreamdump output.
+log_must zfs snapshot $sendfs@now
+log_must eval "zfs send -p $sendfs@now >$stream"
+log_must eval "zstream dump -v <$stream >$dump"
+log_must eval "zfs recv $recvfs <$stream"
+cmp_ds_cont $sendfs $recvfs
+log_must stream_has_features $stream longname
+
+# Ensure the the receiving pool has feature@longname activated after receiving.
+feat_val=$(zpool get -H -o value feature@longname $POOL2)
+log_note "Zpool $POOL2 feature@longname=$feat_val"
+if [[ "$feat_val" != "active" ]]; then
+	log_fail "pool $POOL2 feature@longname=$feat_val (expected 'active')"
+fi
+
+# Receiving of the stream on $POOL3 should fail as longname is not enabled
+log_mustnot eval "zfs recv $recvfs3 <$stream"
+
+# Enable feature@longname and retry the receiving the stream.
+# It should succeed this time.
+log_must eval "zpool set feature@longname=enabled $POOL3"
+log_must eval "zfs recv $recvfs3 <$stream"
+
+log_must zfs get longname $recvfs3
+prop_val=$(zfs get -H -o value longname $recvfs3)
+log_note "dataset $recvfs3 has longname=$prop_val"
+if [[ "$prop_val" != "on" ]]; then
+	log_fail "$recvfs3 has longname=$prop_val (expected 'on')"
+fi
+
+#
+# TODO:
+# - Add a testcase to cover the case where send-stream does not contain
+#   properties (generated without "-p").
+#   In this case the target dataset would have longname files/directories which
+#   cannot be accessed if the dataset property 'longname=off'.
+#
+
+log_pass "Longnames are handled correctly in send/recv"