Support for longnames for files/directories (FreeBSD part/Doesn't work)

Note, FreeBSD vfs layer imposes a limit of 255 name lengh, so even
though we add code to support it here, it won't actually work.

Signed-off-by: Chunwei Chen <[email protected]>

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 */

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,

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);

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;