Support for longnames for files/directories (Linux part)

This patch adds the ability for zfs to support file/dir name up to 1023 bytes. This number is chosen so we can support up to 255 4-byte characters. This new feature is represented by the new feature flag feature@longname. A new dataset property "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. Note that, to my knowledge native Linux filesystems don't support name longer than 255 bytes. So there might be programs not able to work with longname. Note that NFS server may needs to use exportfs_get_name to reconnect dentries, and the buffer being passed is limit to NAME_MAX+1 (256). So NFS may not work when longname is enabled. Signed-off-by: Chunwei Chen <david.chen@nutanix.com>
tuxoko · Aug 1, 2024 · f54bcc9 · f54bcc9
1 parent 647bac0
commit f54bcc9
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Showing 36 changed files with 915 additions and 90 deletions.
diff --git 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
@@ -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/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
@@ -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
@@ -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
@@ -193,6 +194,7 @@ typedef enum {
 	ZFS_PROP_SNAPSHOTS_CHANGED,
 	ZFS_PROP_PREFETCH,
 	ZFS_PROP_VOLTHREADING,
+	ZFS_PROP_LONGNAME,
 	ZFS_NUM_PROPS
 } zfs_prop_t;
 

diff --git 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
@@ -124,7 +124,7 @@ 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)
 /*
  * flag #29 is the last unused bit. It is reserved to indicate a to-be-designed
  * extension to the stream format which will accomodate more feature flags.
@@ -141,7 +141,7 @@ 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
@@ -82,6 +82,7 @@ typedef enum spa_feature {
 	SPA_FEATURE_AVZ_V2,
 	SPA_FEATURE_REDACTION_LIST_SPILL,
 	SPA_FEATURE_RAIDZ_EXPANSION,
+	SPA_FEATURE_LONGNAME,
 	SPA_FEATURES
 } spa_feature_t;
 

diff --git a/lib/libzfs/libzfs.abi b/lib/libzfs/libzfs.abi
@@ -609,7 +609,7 @@
     <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='2296' 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='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'/>
@@ -657,6 +657,10 @@
       <parameter type-id='b59d7dce'/>
       <return type-id='eaa32e2f'/>
     </function-decl>
+    <function-decl name='unlink' visibility='default' binding='global' size-in-bits='64'>
+      <parameter type-id='80f4b756'/>
+      <return type-id='95e97e5e'/>
+    </function-decl>
     <function-decl name='flock' visibility='default' binding='global' size-in-bits='64'>
       <parameter type-id='95e97e5e'/>
       <parameter type-id='95e97e5e'/>
@@ -1852,7 +1856,8 @@
       <enumerator name='ZFS_PROP_SNAPSHOTS_CHANGED' value='95'/>
       <enumerator name='ZFS_PROP_PREFETCH' value='96'/>
       <enumerator name='ZFS_PROP_VOLTHREADING' value='97'/>
-      <enumerator name='ZFS_NUM_PROPS' value='98'/>
+      <enumerator name='ZFS_PROP_LONGNAME' value='98'/>
+      <enumerator name='ZFS_NUM_PROPS' value='99'/>
     </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'>
@@ -3408,18 +3413,9 @@
     <function-decl name='__ctype_b_loc' visibility='default' binding='global' size-in-bits='64'>
       <return type-id='c59e1ef0'/>
     </function-decl>
-    <function-decl name='dlopen' visibility='default' binding='global' size-in-bits='64'>
-      <parameter type-id='80f4b756'/>
-      <parameter type-id='95e97e5e'/>
-      <return type-id='eaa32e2f'/>
-    </function-decl>
-    <function-decl name='dlsym' visibility='default' binding='global' size-in-bits='64'>
-      <parameter type-id='1b7446cd'/>
-      <parameter type-id='9d26089a'/>
-      <return type-id='eaa32e2f'/>
-    </function-decl>
-    <function-decl name='dlerror' visibility='default' binding='global' size-in-bits='64'>
-      <return type-id='26a90f95'/>
+    <function-decl name='uselocale' visibility='default' binding='global' size-in-bits='64'>
+      <parameter type-id='973a4f8d'/>
+      <return type-id='973a4f8d'/>
     </function-decl>
     <function-decl name='uselocale' visibility='default' binding='global' size-in-bits='64'>
       <parameter type-id='973a4f8d'/>
@@ -3466,11 +3462,6 @@
       <parameter type-id='822cd80b'/>
       <return type-id='95e97e5e'/>
     </function-decl>
-    <function-decl name='fdopen' visibility='default' binding='global' size-in-bits='64'>
-      <parameter type-id='95e97e5e'/>
-      <parameter type-id='80f4b756'/>
-      <return type-id='822cd80b'/>
-    </function-decl>
     <function-decl name='fputc' visibility='default' binding='global' size-in-bits='64'>
       <parameter type-id='95e97e5e'/>
       <parameter type-id='822cd80b'/>
@@ -3483,10 +3474,6 @@
       <parameter type-id='e75a27e9'/>
       <return type-id='41060289'/>
     </function-decl>
-    <function-decl name='rewind' visibility='default' binding='global' size-in-bits='64'>
-      <parameter type-id='822cd80b'/>
-      <return type-id='48b5725f'/>
-    </function-decl>
     <function-decl name='ferror' visibility='default' binding='global' size-in-bits='64'>
       <parameter type-id='822cd80b'/>
       <return type-id='95e97e5e'/>
@@ -3535,10 +3522,6 @@
       <parameter type-id='95e97e5e'/>
       <return type-id='95e97e5e'/>
     </function-decl>
-    <function-decl name='unlink' visibility='default' binding='global' size-in-bits='64'>
-      <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>
@@ -3551,13 +3534,6 @@
       <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'/>
@@ -4364,6 +4340,10 @@
     <function-decl name='abort' visibility='default' binding='global' size-in-bits='64'>
       <return type-id='48b5725f'/>
     </function-decl>
+    <function-decl name='strdup' visibility='default' binding='global' size-in-bits='64'>
+      <parameter type-id='80f4b756'/>
+      <return type-id='26a90f95'/>
+    </function-decl>
     <function-decl name='strrchr' visibility='default' binding='global' size-in-bits='64'>
       <parameter type-id='80f4b756'/>
       <parameter type-id='95e97e5e'/>
@@ -4403,6 +4383,13 @@
       <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='ioctl' visibility='default' binding='global' size-in-bits='64'>
       <parameter type-id='95e97e5e'/>
       <parameter type-id='7359adad'/>
@@ -4933,6 +4920,11 @@
       <parameter type-id='4051f5e7'/>
       <return type-id='95e97e5e'/>
     </function-decl>
+    <function-decl name='fdopen' visibility='default' binding='global' size-in-bits='64'>
+      <parameter type-id='95e97e5e'/>
+      <parameter type-id='80f4b756'/>
+      <return type-id='822cd80b'/>
+    </function-decl>
     <function-decl name='fputs' visibility='default' binding='global' size-in-bits='64'>
       <parameter type-id='9d26089a'/>
       <parameter type-id='e75a27e9'/>
@@ -5987,7 +5979,8 @@
       <enumerator name='SPA_FEATURE_AVZ_V2' value='38'/>
       <enumerator name='SPA_FEATURE_REDACTION_LIST_SPILL' value='39'/>
       <enumerator name='SPA_FEATURE_RAIDZ_EXPANSION' value='40'/>
-      <enumerator name='SPA_FEATURES' value='41'/>
+      <enumerator name='SPA_FEATURE_LONGNAME' value='41'/>
+      <enumerator name='SPA_FEATURES' value='42'/>
     </enum-decl>
     <typedef-decl name='spa_feature_t' type-id='33ecb627' id='d6618c78'/>
     <qualified-type-def type-id='80f4b756' const='yes' id='b99c00c9'/>
@@ -8023,10 +8016,6 @@
     <function-decl name='__ctype_toupper_loc' visibility='default' binding='global' size-in-bits='64'>
       <return type-id='24f95ba5'/>
     </function-decl>
-    <function-decl name='dlclose' visibility='default' binding='global' size-in-bits='64'>
-      <parameter type-id='eaa32e2f'/>
-      <return type-id='95e97e5e'/>
-    </function-decl>
     <function-decl name='regcomp' visibility='default' binding='global' size-in-bits='64'>
       <parameter type-id='5c53ba29'/>
       <parameter type-id='9d26089a'/>
@@ -9072,8 +9061,8 @@
     </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='18368' id='b93e4d14'>
-      <subrange length='41' type-id='7359adad' id='cb834f44'/>
+    <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>
     <enum-decl name='zfeature_flags' id='6db816a4'>
       <underlying-type type-id='9cac1fee'/>
@@ -9150,7 +9139,7 @@
     <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='b93e4d14' mangled-name='spa_feature_table' visibility='default' elf-symbol-id='spa_feature_table'/>
+    <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='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/module/os/freebsd/zfs/zfs_vnops_os.c b/module/os/freebsd/zfs/zfs_vnops_os.c
@@ -1841,7 +1841,7 @@ zfs_readdir(vnode_t *vp, zfs_uio_t *uio, cred_t *cr, int *eofp,
 			/*
 			 * Grab next entry.
 			 */
-			if ((error = zap_cursor_retrieve(&zc, &zap))) {
+			if ((error = zap_cursor_retrieve(&zc, zap))) {
 				if ((*eofp = (error == ENOENT)) != 0)
 					break;
 				else

diff --git a/module/os/freebsd/zfs/zfs_znode.c b/module/os/freebsd/zfs/zfs_znode.c
@@ -1978,7 +1978,7 @@ zfs_obj_to_path_impl(objset_t *osp, uint64_t obj, sa_handle_t *hdl,
 			(void) sprintf(component + 1, "<xattrdir>");
 		} else {
 			error = zap_value_search(osp, pobj, obj,
-			    ZFS_DIRENT_OBJ(-1ULL), component + 1);
+			    ZFS_DIRENT_OBJ(-1ULL), component + 1, MAXNAMELEN);
 			if (error != 0)
 				break;
 		}
@@ -2191,7 +2191,7 @@ 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, MAXNAMELEN);
 	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
@@ -802,6 +802,7 @@ zfs_link_create(zfs_dirlock_t *dl, znode_t *zp, dmu_tx_t *tx, int flag)
 {
 	znode_t *dzp = dl->dl_dzp;
 	zfsvfs_t *zfsvfs = ZTOZSB(zp);
+	dsl_dataset_t *ds = dmu_objset_ds(zfsvfs->z_os);
 	uint64_t value;
 	int zp_is_dir = S_ISDIR(ZTOI(zp)->i_mode);
 	sa_bulk_attr_t bulk[5];
@@ -847,6 +848,14 @@ 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) {
+		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
@@ -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 "zfs_comutil.h"
@@ -448,6 +449,12 @@ 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)
 {
@@ -508,6 +515,8 @@ 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;
@@ -1139,7 +1148,8 @@ 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.