From: Lai Siyao <lai.siyao@intel.com>
Date: Tue, 3 Mar 2015 12:36:31 +0000 (+0800)
Subject: LU-28 fileset: add fileset mount support
X-Git-Tag: 2.8.52~5
X-Git-Url: https://git.whamcloud.com/?a=commitdiff_plain;h=refs%2Fchanges%2F07%2F5007%2F39;p=fs%2Flustre-release.git

LU-28 fileset: add fileset mount support

This patch enables client to mount subdirectory as fileset.

usage: mount -t lustre mgsname:/fsname/subdir /mount/point

* mdt lookup fileset fid and return to client during mount.
* `lfs fid2path` support for fileset.

Test-Parameters: envdefinitions=FILESET=/somedir testlist=sanity
Signed-off-by: Lai Siyao <lai.siyao@intel.com>
Signed-off-by: Kit Westneat <kwestneat@ddn.com>
Signed-off-by: Wang Shilong <wshilong@ddn.com>
Change-Id: I947785de3b053907600d1090c80e8f57396e1e93
Reviewed-on: http://review.whamcloud.com/5007
Tested-by: Jenkins
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Li Xi <lixi@ddn.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>
---

diff --git a/lustre/contrib/wireshark/packet-lustre.c b/lustre/contrib/wireshark/packet-lustre.c
index 27640f6..e07576b 100644
--- a/lustre/contrib/wireshark/packet-lustre.c
+++ b/lustre/contrib/wireshark/packet-lustre.c
@@ -205,7 +205,7 @@ typedef enum {
 	MDS_READPAGE		= 37,
 	MDS_CONNECT		= 38,
 	MDS_DISCONNECT		= 39,
-	MDS_GETSTATUS		= 40,
+	MDS_GET_ROOT		= 40,
 	MDS_STATFS		= 41,
 	MDS_PIN			= 42,
 	MDS_UNPIN		= 43,
@@ -1162,7 +1162,7 @@ const value_string lustre_op_codes[] = {
   {37 , "MDS_READPAGE"},
   {38 , "MDS_CONNECT"},
   {39 , "MDS_DISCONNECT"},
-  {40 , "MDS_GETSTATUS"},
+  {40 , "MDS_GET_ROOT"},
   {41 , "MDS_STATFS"},
   {42 , "MDS_PIN"},
   {43 , "MDS_UNPIN"},
@@ -8590,7 +8590,7 @@ lustre_mds_opcode_process(tvbuff_t *tvb _U_, int offset _U_, packet_info *pinfo
     case MDS_DISCONNECT:
       /*[nothing]*/
       break;
-    case MDS_GETSTATUS:
+    case MDS_GET_ROOT:
       /*request: [mds body]*/
       /*reply:   [mds body][capa] */
       offset=lustre_dissect_struct_mdt_body(tvb, offset, pinfo, tree, hf_lustre_mdt_body) ;
diff --git a/lustre/doc/mount.lustre.8 b/lustre/doc/mount.lustre.8
index 027dc4e..c020ae2 100644
--- a/lustre/doc/mount.lustre.8
+++ b/lustre/doc/mount.lustre.8
@@ -25,10 +25,12 @@ There are two forms for the
 .I device
 option, depending on whether a client or a target service is started:
 .TP
-.IR <mgsspec> :/ <fsname>
+.IR <mgsspec> :/ <fsname>[/<subdir>]
 mounts the Lustre filesystem named
 .I fsname
-on the client by contacting the Management Service at 
+(under subdirectory
+.I subdir
+if specified) on the client by contacting the Management Service at
 .IR mgsspec 
 on the pathname given by
 .IR directory .
@@ -150,6 +152,9 @@ Start a client for the Lustre filesystem 'testfs' at the mount point
 /mnt/myfilesystem. The Management Service is running on a node reachable
 from this client via the nid cfs21@tcp0.
 .TP
+.B mount -t lustre cfs21@tcp0:/testfs/dir /mnt/myfilesystem
+Like above example, but mount subdirectory 'dir' as fileset.
+.TP
 .B mount -t lustre /dev/sda1 /mnt/test/mdt
 Start the Lustre metadata target service from /dev/sda1 on mountpoint /mnt/test/mdt.
 .TP
diff --git a/lustre/include/lustre/lustre_idl.h b/lustre/include/lustre/lustre_idl.h
index 9bff175..713f99d 100644
--- a/lustre/include/lustre/lustre_idl.h
+++ b/lustre/include/lustre/lustre_idl.h
@@ -1296,7 +1296,8 @@ struct ptlrpc_body_v2 {
 				OBD_CONNECT_OPEN_BY_FID | \
 				OBD_CONNECT_DIR_STRIPE | \
 				OBD_CONNECT_BULK_MBITS | \
-				OBD_CONNECT_MULTIMODRPCS)
+				OBD_CONNECT_MULTIMODRPCS | \
+				OBD_CONNECT_SUBTREE)
 
 #define OST_CONNECT_SUPPORTED  (OBD_CONNECT_SRVLOCK | OBD_CONNECT_GRANT | \
                                 OBD_CONNECT_REQPORTAL | OBD_CONNECT_VERSION | \
@@ -2005,7 +2006,7 @@ typedef enum {
 	MDS_READPAGE		= 37,
 	MDS_CONNECT		= 38,
 	MDS_DISCONNECT		= 39,
-	MDS_GETSTATUS		= 40,
+	MDS_GET_ROOT		= 40,
 	MDS_STATFS		= 41,
 	MDS_PIN			= 42, /* obsolete, never used in a release */
 	MDS_UNPIN		= 43, /* obsolete, never used in a release */
@@ -3691,11 +3692,14 @@ struct link_ea_entry {
 
 /** fid2path request/reply structure */
 struct getinfo_fid2path {
-        struct lu_fid   gf_fid;
-        __u64           gf_recno;
-        __u32           gf_linkno;
-        __u32           gf_pathlen;
-        char            gf_path[0];
+	struct lu_fid	gf_fid;
+	__u64		gf_recno;
+	__u32		gf_linkno;
+	__u32		gf_pathlen;
+	union {
+		char		gf_path[0];
+		struct lu_fid	gf_root_fid[0];
+	} gf_u;
 } __attribute__((packed));
 
 /** path2parent request/reply structures */
diff --git a/lustre/include/lustre/lustreapi.h b/lustre/include/lustre/lustreapi.h
index 340bec5..e680b4e 100644
--- a/lustre/include/lustre/lustreapi.h
+++ b/lustre/include/lustre/lustreapi.h
@@ -266,6 +266,7 @@ extern int llapi_search_mounts(const char *pathname, int index,
                                char *mntdir, char *fsname);
 extern int llapi_search_fsname(const char *pathname, char *fsname);
 extern int llapi_getname(const char *path, char *buf, size_t size);
+extern int llapi_search_fileset(const char *pathname, char *fileset);
 
 extern int llapi_search_rootpath(char *pathname, const char *fsname);
 extern int llapi_nodemap_exists(const char *name);
diff --git a/lustre/include/lustre_disk.h b/lustre/include/lustre_disk.h
index 653349d..b56385e5 100644
--- a/lustre/include/lustre_disk.h
+++ b/lustre/include/lustre_disk.h
@@ -219,21 +219,22 @@ static inline int server_make_name(__u32 flags, __u16 index, char *fs,
 
 /* gleaned from the mount command - no persistent info here */
 struct lustre_mount_data {
-        __u32      lmd_magic;
-        __u32      lmd_flags;         /* lustre mount flags */
-        int        lmd_mgs_failnodes; /* mgs failover node count */
-        int        lmd_exclude_count;
-        int        lmd_recovery_time_soft;
-        int        lmd_recovery_time_hard;
-        char      *lmd_dev;           /* device name */
-        char      *lmd_profile;       /* client only */
-        char      *lmd_mgssec;        /* sptlrpc flavor to mgs */
-        char      *lmd_opts;          /* lustre mount options (as opposed to
-                                         _device_ mount options) */
-	char      *lmd_params;        /* lustre params */
-        __u32     *lmd_exclude;       /* array of OSTs to ignore */
-	char	*lmd_mgs;           /* MGS nid */
-	char	*lmd_osd_type;      /* OSD type */
+	__u32	lmd_magic;
+	__u32	lmd_flags;	/* lustre mount flags */
+	int	lmd_mgs_failnodes; /* mgs failover node count */
+	int	lmd_exclude_count;
+	int	lmd_recovery_time_soft;
+	int	lmd_recovery_time_hard;
+	char   *lmd_dev;	/* device name */
+	char   *lmd_profile;	/* client only */
+	char   *lmd_fileset;	/* mount fileset */
+	char   *lmd_mgssec;	/* sptlrpc flavor to mgs */
+	char   *lmd_opts;	/* lustre mount options (as opposed to
+				 * device_ mount options) */
+	char   *lmd_params;	/* lustre params */
+	__u32  *lmd_exclude;	/* array of OSTs to ignore */
+	char   *lmd_mgs;	/* MGS nid */
+	char   *lmd_osd_type;	/* OSD type */
 };
 
 #define LMD_FLG_SERVER		0x0001	/* Mounting a server */
@@ -550,6 +551,7 @@ struct lustre_sb_info {
 #define     get_profile_name(sb)   (s2lsi(sb)->lsi_lmd->lmd_profile)
 #define	    get_mount_flags(sb)	   (s2lsi(sb)->lsi_lmd->lmd_flags)
 #define	    get_mntdev_name(sb)	   (s2lsi(sb)->lsi_lmd->lmd_dev)
+#define     get_mount_fileset(sb)  (s2lsi(sb)->lsi_lmd->lmd_fileset)
 
 #endif /* __KERNEL__ */
 
diff --git a/lustre/include/lustre_req_layout.h b/lustre/include/lustre_req_layout.h
index 5a124b4..134edba 100644
--- a/lustre/include/lustre_req_layout.h
+++ b/lustre/include/lustre_req_layout.h
@@ -155,7 +155,7 @@ extern struct req_format RQF_FLD_READ;
 extern struct req_format RQF_MDS_CONNECT;
 extern struct req_format RQF_MDS_DISCONNECT;
 extern struct req_format RQF_MDS_STATFS;
-extern struct req_format RQF_MDS_GETSTATUS;
+extern struct req_format RQF_MDS_GET_ROOT;
 extern struct req_format RQF_MDS_SYNC;
 extern struct req_format RQF_MDS_GETXATTR;
 extern struct req_format RQF_MDS_GETATTR;
diff --git a/lustre/include/obd.h b/lustre/include/obd.h
index 7ed95ea..31232e4 100644
--- a/lustre/include/obd.h
+++ b/lustre/include/obd.h
@@ -1069,7 +1069,8 @@ struct md_ops {
 
 #define MD_STATS_LAST_OP m_revalidate_lock
 
-	int (*m_getstatus)(struct obd_export *, struct lu_fid *);
+	int (*m_getstatus)(struct obd_export *, const char *fileset,
+			   struct lu_fid *);
 	int (*m_null_inode)(struct obd_export *, const struct lu_fid *);
 
 	int (*m_getattr_name)(struct obd_export *, struct md_op_data *,
diff --git a/lustre/include/obd_class.h b/lustre/include/obd_class.h
index 9e4b99d..2941e10 100644
--- a/lustre/include/obd_class.h
+++ b/lustre/include/obd_class.h
@@ -1267,14 +1267,15 @@ static inline int obd_register_observer(struct obd_device *obd,
 }
 
 /* metadata helpers */
-static inline int md_getstatus(struct obd_export *exp, struct lu_fid *fid)
+static inline int md_get_root(struct obd_export *exp, const char *fileset,
+			      struct lu_fid *fid)
 {
 	int rc;
 
 	ENTRY;
 	EXP_CHECK_MD_OP(exp, getstatus);
 	EXP_MD_COUNTER_INCREMENT(exp, getstatus);
-	rc = MDP(exp->exp_obd, getstatus)(exp, fid);
+	rc = MDP(exp->exp_obd, getstatus)(exp, fileset, fid);
 
 	RETURN(rc);
 }
diff --git a/lustre/include/obd_support.h b/lustre/include/obd_support.h
index ce28659..71b4792 100644
--- a/lustre/include/obd_support.h
+++ b/lustre/include/obd_support.h
@@ -183,8 +183,8 @@ extern char obd_jobid_var[];
 #define OBD_FAIL_MDS_CONNECT_PACK        0x118
 #define OBD_FAIL_MDS_REINT_NET_REP       0x119
 #define OBD_FAIL_MDS_DISCONNECT_NET      0x11a
-#define OBD_FAIL_MDS_GETSTATUS_NET       0x11b
-#define OBD_FAIL_MDS_GETSTATUS_PACK      0x11c
+#define OBD_FAIL_MDS_GET_ROOT_NET	 0x11b
+#define OBD_FAIL_MDS_GET_ROOT_PACK	 0x11c
 #define OBD_FAIL_MDS_STATFS_PACK         0x11d
 #define OBD_FAIL_MDS_STATFS_NET          0x11e
 #define OBD_FAIL_MDS_GETATTR_NAME_NET    0x11f
diff --git a/lustre/llite/file.c b/lustre/llite/file.c
index ff1dd64..2eb5b75 100644
--- a/lustre/llite/file.c
+++ b/lustre/llite/file.c
@@ -1838,6 +1838,10 @@ int ll_fid2path(struct inode *inode, void __user *arg)
 
 	if (copy_from_user(gfout, arg, sizeof(*gfout)))
 		GOTO(gf_free, rc = -EFAULT);
+	/* append root FID after gfout to let MDT know the root FID so that it
+	 * can lookup the correct path, this is mainly for fileset.
+	 * old server without fileset mount support will ignore this. */
+	*gfout->gf_u.gf_root_fid = *ll_inode2fid(inode);
 
 	/* Call mdc_iocontrol */
 	rc = obd_iocontrol(OBD_IOC_FID2PATH, exp, outsize, gfout, NULL);
@@ -3120,6 +3124,14 @@ int ll_migrate(struct inode *parent, struct file *file, int mdtidx,
 	if (child_inode == NULL)
 		GOTO(out_free, rc = -EINVAL);
 
+	/*
+	 * lfs migrate command needs to be blocked on the client
+	 * by checking the migrate FID against the FID of the
+	 * filesystem root.
+	 */
+	if (child_inode == parent->i_sb->s_root->d_inode)
+		GOTO(out_iput, rc = -EINVAL);
+
 	mutex_lock(&child_inode->i_mutex);
 	op_data->op_fid3 = *ll_inode2fid(child_inode);
 	if (!fid_is_sane(&op_data->op_fid3)) {
@@ -3199,6 +3211,7 @@ out_close:
 		clear_nlink(child_inode);
 out_unlock:
 	mutex_unlock(&child_inode->i_mutex);
+out_iput:
 	iput(child_inode);
 out_free:
 	ll_finish_md_op_data(op_data);
diff --git a/lustre/llite/llite_lib.c b/lustre/llite/llite_lib.c
index 7ecc93c..5674ca4 100644
--- a/lustre/llite/llite_lib.c
+++ b/lustre/llite/llite_lib.c
@@ -209,7 +209,8 @@ static int client_common_fill_super(struct super_block *sb, char *md, char *dt,
 				  OBD_CONNECT_DISP_STRIPE | OBD_CONNECT_LFSCK |
 				  OBD_CONNECT_OPEN_BY_FID |
 				  OBD_CONNECT_DIR_STRIPE |
-				  OBD_CONNECT_BULK_MBITS;
+				  OBD_CONNECT_BULK_MBITS |
+				  OBD_CONNECT_SUBTREE;
 
 #ifdef HAVE_LRU_RESIZE_SUPPORT
         if (sbi->ll_flags & LL_SBI_LRU_RESIZE)
@@ -473,7 +474,8 @@ static int client_common_fill_super(struct super_block *sb, char *md, char *dt,
 	mutex_unlock(&sbi->ll_lco.lco_lock);
 
 	fid_zero(&sbi->ll_root_fid);
-	err = md_getstatus(sbi->ll_md_exp, &sbi->ll_root_fid);
+	err = md_get_root(sbi->ll_md_exp, get_mount_fileset(sb),
+			   &sbi->ll_root_fid);
 	if (err) {
 		CERROR("cannot mds_connect: rc = %d\n", err);
 		GOTO(out_lock_cn_cb, err);
diff --git a/lustre/lmv/lmv_obd.c b/lustre/lmv/lmv_obd.c
index 0198517..0b7a1f0 100644
--- a/lustre/lmv/lmv_obd.c
+++ b/lustre/lmv/lmv_obd.c
@@ -691,14 +691,18 @@ static int lmv_fid2path(struct obd_export *exp, int len, void *karg,
 	struct getinfo_fid2path *gf;
 	struct lmv_tgt_desc     *tgt;
 	struct getinfo_fid2path *remote_gf = NULL;
+	struct lu_fid		root_fid;
 	int			remote_gf_size = 0;
 	int			rc;
 
-	gf = (struct getinfo_fid2path *)karg;
+	gf = karg;
 	tgt = lmv_find_target(lmv, &gf->gf_fid);
 	if (IS_ERR(tgt))
 		RETURN(PTR_ERR(tgt));
 
+	root_fid = *gf->gf_u.gf_root_fid;
+	LASSERT(fid_is_sane(&root_fid));
+
 repeat_fid2path:
 	rc = obd_iocontrol(OBD_IOC_FID2PATH, tgt->ltd_exp, len, gf, uarg);
 	if (rc != 0 && rc != -EREMOTE)
@@ -711,23 +715,24 @@ repeat_fid2path:
 		char *ptr;
 
 		ori_gf = (struct getinfo_fid2path *)karg;
-		if (strlen(ori_gf->gf_path) +
-		    strlen(gf->gf_path) > ori_gf->gf_pathlen)
+		if (strlen(ori_gf->gf_u.gf_path) +
+		    strlen(gf->gf_u.gf_path) > ori_gf->gf_pathlen)
 			GOTO(out_fid2path, rc = -EOVERFLOW);
 
-		ptr = ori_gf->gf_path;
+		ptr = ori_gf->gf_u.gf_path;
 
-		memmove(ptr + strlen(gf->gf_path) + 1, ptr,
-			strlen(ori_gf->gf_path));
+		memmove(ptr + strlen(gf->gf_u.gf_path) + 1, ptr,
+			strlen(ori_gf->gf_u.gf_path));
 
-		strncpy(ptr, gf->gf_path, strlen(gf->gf_path));
-		ptr += strlen(gf->gf_path);
+		strncpy(ptr, gf->gf_u.gf_path,
+			strlen(gf->gf_u.gf_path));
+		ptr += strlen(gf->gf_u.gf_path);
 		*ptr = '/';
 	}
 
 	CDEBUG(D_INFO, "%s: get path %s "DFID" rec: "LPU64" ln: %u\n",
 	       tgt->ltd_exp->exp_obd->obd_name,
-	       gf->gf_path, PFID(&gf->gf_fid), gf->gf_recno,
+	       gf->gf_u.gf_path, PFID(&gf->gf_fid), gf->gf_recno,
 	       gf->gf_linkno);
 
 	if (rc == 0)
@@ -756,7 +761,8 @@ repeat_fid2path:
 	remote_gf->gf_fid = gf->gf_fid;
 	remote_gf->gf_recno = -1;
 	remote_gf->gf_linkno = -1;
-	memset(remote_gf->gf_path, 0, remote_gf->gf_pathlen);
+	memset(remote_gf->gf_u.gf_path, 0, remote_gf->gf_pathlen);
+	*remote_gf->gf_u.gf_root_fid = root_fid;
 	gf = remote_gf;
 	goto repeat_fid2path;
 
@@ -1492,18 +1498,20 @@ out_free_temp:
         return rc;
 }
 
-static int lmv_getstatus(struct obd_export *exp, struct lu_fid *fid)
+static int lmv_getstatus(struct obd_export *exp,
+			 const char *fileset,
+			 struct lu_fid *fid)
 {
         struct obd_device    *obd = exp->exp_obd;
         struct lmv_obd       *lmv = &obd->u.lmv;
         int                   rc;
         ENTRY;
 
-        rc = lmv_check_connect(obd);
-        if (rc)
-                RETURN(rc);
+	rc = lmv_check_connect(obd);
+	if (rc)
+		RETURN(rc);
 
-	rc = md_getstatus(lmv->tgts[0]->ltd_exp, fid);
+	rc = md_get_root(lmv->tgts[0]->ltd_exp, fileset, fid);
 	RETURN(rc);
 }
 
diff --git a/lustre/mdc/mdc_request.c b/lustre/mdc/mdc_request.c
index 090d6fa..ef49a28 100644
--- a/lustre/mdc/mdc_request.c
+++ b/lustre/mdc/mdc_request.c
@@ -84,7 +84,22 @@ static inline int mdc_queue_wait(struct ptlrpc_request *req)
 	return rc;
 }
 
-static int mdc_getstatus(struct obd_export *exp, struct lu_fid *rootfid)
+/*
+ * Send MDS_GET_ROOT RPC to fetch root FID.
+ *
+ * If \a fileset is not NULL it should contain a subdirectory off
+ * the ROOT/ directory to be mounted on the client. Return the FID
+ * of the subdirectory to the client to mount onto its mountpoint.
+ *
+ * \param[in]	imp	MDC import
+ * \param[in]	fileset	fileset name, which could be NULL
+ * \param[out]	rootfid	root FID of this mountpoint
+ * \param[out]	pc	root capa will be unpacked and saved in this pointer
+ *
+ * \retval	0 on success, negative errno on failure
+ */
+static int mdc_get_root(struct obd_export *exp, const char *fileset,
+			 struct lu_fid *rootfid)
 {
 	struct ptlrpc_request	*req;
 	struct mdt_body		*body;
@@ -92,13 +107,29 @@ static int mdc_getstatus(struct obd_export *exp, struct lu_fid *rootfid)
 
 	ENTRY;
 
-	req = ptlrpc_request_alloc_pack(class_exp2cliimp(exp),
-					&RQF_MDS_GETSTATUS,
-					LUSTRE_MDS_VERSION, MDS_GETSTATUS);
+	if (fileset && !(exp_connect_flags(exp) & OBD_CONNECT_SUBTREE))
+		RETURN(-ENOTSUPP);
+
+	req = ptlrpc_request_alloc(class_exp2cliimp(exp),
+				&RQF_MDS_GET_ROOT);
 	if (req == NULL)
 		RETURN(-ENOMEM);
 
+	if (fileset != NULL)
+		req_capsule_set_size(&req->rq_pill, &RMF_NAME, RCL_CLIENT,
+				     strlen(fileset) + 1);
+	rc = ptlrpc_request_pack(req, LUSTRE_MDS_VERSION, MDS_GET_ROOT);
+	if (rc) {
+		ptlrpc_request_free(req);
+		RETURN(rc);
+	}
 	mdc_pack_body(req, NULL, 0, 0, -1, 0);
+	if (fileset != NULL) {
+		char *name = req_capsule_client_get(&req->rq_pill, &RMF_NAME);
+
+		memcpy(name, fileset, strlen(fileset));
+	}
+	lustre_msg_add_flags(req->rq_reqmsg, LUSTRE_IMP_FULL);
 	req->rq_send_state = LUSTRE_IMP_FULL;
 
 	ptlrpc_request_set_replen(req);
@@ -1445,28 +1476,30 @@ output:
 
 static int mdc_ioc_fid2path(struct obd_export *exp, struct getinfo_fid2path *gf)
 {
-        __u32 keylen, vallen;
-        void *key;
-        int rc;
-
-        if (gf->gf_pathlen > PATH_MAX)
-                RETURN(-ENAMETOOLONG);
-        if (gf->gf_pathlen < 2)
-                RETURN(-EOVERFLOW);
+	__u32 keylen, vallen;
+	void *key;
+	int rc;
 
-        /* Key is KEY_FID2PATH + getinfo_fid2path description */
-        keylen = cfs_size_round(sizeof(KEY_FID2PATH)) + sizeof(*gf);
-        OBD_ALLOC(key, keylen);
-        if (key == NULL)
-                RETURN(-ENOMEM);
-        memcpy(key, KEY_FID2PATH, sizeof(KEY_FID2PATH));
-        memcpy(key + cfs_size_round(sizeof(KEY_FID2PATH)), gf, sizeof(*gf));
+	if (gf->gf_pathlen > PATH_MAX)
+		RETURN(-ENAMETOOLONG);
+	if (gf->gf_pathlen < 2)
+		RETURN(-EOVERFLOW);
 
-        CDEBUG(D_IOCTL, "path get "DFID" from "LPU64" #%d\n",
-               PFID(&gf->gf_fid), gf->gf_recno, gf->gf_linkno);
+	/* Key is KEY_FID2PATH + getinfo_fid2path description */
+	keylen = cfs_size_round(sizeof(KEY_FID2PATH) + sizeof(*gf) +
+				sizeof(struct lu_fid));
+	OBD_ALLOC(key, keylen);
+	if (key == NULL)
+		RETURN(-ENOMEM);
+	memcpy(key, KEY_FID2PATH, sizeof(KEY_FID2PATH));
+	memcpy(key + cfs_size_round(sizeof(KEY_FID2PATH)), gf, sizeof(*gf));
+	memcpy(key + cfs_size_round(sizeof(KEY_FID2PATH)) + sizeof(*gf),
+	       gf->gf_u.gf_root_fid, sizeof(struct lu_fid));
+	CDEBUG(D_IOCTL, "path get "DFID" from "LPU64" #%d\n",
+	       PFID(&gf->gf_fid), gf->gf_recno, gf->gf_linkno);
 
-        if (!fid_is_sane(&gf->gf_fid))
-                GOTO(out, rc = -EINVAL);
+	if (!fid_is_sane(&gf->gf_fid))
+		GOTO(out, rc = -EINVAL);
 
         /* Val is struct getinfo_fid2path result plus path */
         vallen = sizeof(*gf) + gf->gf_pathlen;
@@ -1482,9 +1515,9 @@ static int mdc_ioc_fid2path(struct obd_export *exp, struct getinfo_fid2path *gf)
 
 	CDEBUG(D_IOCTL, "path got "DFID" from "LPU64" #%d: %s\n",
 	       PFID(&gf->gf_fid), gf->gf_recno, gf->gf_linkno,
-	       gf->gf_pathlen < 512 ? gf->gf_path :
+	       gf->gf_pathlen < 512 ? gf->gf_u.gf_path :
 	       /* only log the last 512 characters of the path */
-	       gf->gf_path + gf->gf_pathlen - 512);
+	       gf->gf_u.gf_path + gf->gf_pathlen - 512);
 
 out:
 	OBD_FREE(key, keylen);
@@ -2758,7 +2791,7 @@ static struct obd_ops mdc_obd_ops = {
 };
 
 static struct md_ops mdc_md_ops = {
-        .m_getstatus        = mdc_getstatus,
+	.m_getstatus        = mdc_get_root,
         .m_null_inode	    = mdc_null_inode,
         .m_close            = mdc_close,
         .m_create           = mdc_create,
diff --git a/lustre/mdt/mdt_handler.c b/lustre/mdt/mdt_handler.c
index 3f16666..7d7f052 100644
--- a/lustre/mdt/mdt_handler.c
+++ b/lustre/mdt/mdt_handler.c
@@ -65,6 +65,8 @@
 #include <obd.h>
 #include <obd_support.h>
 
+#include <llog_swab.h>
+
 #include "mdt_internal.h"
 
 
@@ -266,11 +268,87 @@ static void mdt_lock_pdo_mode(struct mdt_thread_info *info, struct mdt_object *o
         EXIT;
 }
 
-static int mdt_getstatus(struct tgt_session_info *tsi)
+static int mdt_lookup_fileset(struct mdt_thread_info *info, const char *fileset,
+			      struct lu_fid *fid)
+{
+	struct mdt_device *mdt = info->mti_mdt;
+	struct lu_name *lname = &info->mti_name;
+	char *name = NULL;
+	struct mdt_object *parent;
+	u32 mode;
+	int rc = 0;
+
+	LASSERT(!info->mti_cross_ref);
+
+	OBD_ALLOC(name, NAME_MAX + 1);
+	if (name == NULL)
+		return -ENOMEM;
+	lname->ln_name = name;
+
+	/*
+	 * We may want to allow this to mount a completely separate
+	 * fileset from the MDT in the future, but keeping it to
+	 * ROOT/ only for now avoid potential security issues.
+	 */
+	*fid = mdt->mdt_md_root_fid;
+
+	while (rc == 0 && fileset != NULL && *fileset != '\0') {
+		const char *s1 = fileset;
+		const char *s2;
+
+		while (*++s1 == '/')
+			;
+		s2 = s1;
+		while (*s2 != '/' && *s2 != '\0')
+			s2++;
+
+		if (s2 == s1)
+			break;
+
+		fileset = s2;
+
+		lname->ln_namelen = s2 - s1;
+		if (lname->ln_namelen > NAME_MAX) {
+			rc = -EINVAL;
+			break;
+		}
+		strncpy(name, s1, lname->ln_namelen);
+		name[lname->ln_namelen] = '\0';
+
+		parent = mdt_object_find(info->mti_env, mdt, fid);
+		if (IS_ERR(parent)) {
+			rc = PTR_ERR(parent);
+			break;
+		}
+		/* Only got the fid of this obj by name */
+		fid_zero(fid);
+		rc = mdo_lookup(info->mti_env, mdt_object_child(parent), lname,
+				fid, &info->mti_spec);
+		mdt_object_put(info->mti_env, parent);
+	}
+	if (!rc) {
+		parent = mdt_object_find(info->mti_env, mdt, fid);
+		if (IS_ERR(parent))
+			rc = PTR_ERR(parent);
+		else {
+			mode = lu_object_attr(&parent->mot_obj);
+			mdt_object_put(info->mti_env, parent);
+			if (!S_ISDIR(mode))
+				rc = -ENOTDIR;
+		}
+	}
+
+	OBD_FREE(name, NAME_MAX + 1);
+
+	return rc;
+}
+
+static int mdt_get_root(struct tgt_session_info *tsi)
 {
 	struct mdt_thread_info	*info = tsi2mdt_info(tsi);
 	struct mdt_device	*mdt = info->mti_mdt;
 	struct mdt_body		*repbody;
+	char			*fileset;
 	int			 rc;
 
 	ENTRY;
@@ -279,11 +357,21 @@ static int mdt_getstatus(struct tgt_session_info *tsi)
 	if (rc)
 		GOTO(out, rc = err_serious(rc));
 
-	if (OBD_FAIL_CHECK(OBD_FAIL_MDS_GETSTATUS_PACK))
+	if (OBD_FAIL_CHECK(OBD_FAIL_MDS_GET_ROOT_PACK))
 		GOTO(out, rc = err_serious(-ENOMEM));
 
 	repbody = req_capsule_server_get(info->mti_pill, &RMF_MDT_BODY);
-	repbody->mbo_fid1 = mdt->mdt_md_root_fid;
+	if (req_capsule_get_size(info->mti_pill, &RMF_NAME, RCL_CLIENT) > 0) {
+		fileset = req_capsule_client_get(info->mti_pill, &RMF_NAME);
+		if (fileset == NULL)
+			GOTO(out, rc = err_serious(-EFAULT));
+
+		rc = mdt_lookup_fileset(info, fileset, &repbody->mbo_fid1);
+		if (rc < 0)
+			GOTO(out, rc = err_serious(rc));
+	} else {
+		repbody->mbo_fid1 = mdt->mdt_md_root_fid;
+	}
 	repbody->mbo_valid |= OBD_MD_FLID;
 
 	EXIT;
@@ -4241,7 +4329,7 @@ TGT_RPC_HANDLER(MDS_FIRST_OPC,
 		HABEO_REFERO,		MDS_SET_INFO,	mdt_set_info,
 		&RQF_OBD_SET_INFO, LUSTRE_MDS_VERSION),
 TGT_MDT_HDL(0,				MDS_GET_INFO,	mdt_get_info),
-TGT_MDT_HDL(0		| HABEO_REFERO,	MDS_GETSTATUS,	mdt_getstatus),
+TGT_MDT_HDL(0		| HABEO_REFERO,	MDS_GET_ROOT,	mdt_get_root),
 TGT_MDT_HDL(HABEO_CORPUS,		MDS_GETATTR,	mdt_getattr),
 TGT_MDT_HDL(HABEO_CORPUS| HABEO_REFERO,	MDS_GETATTR_NAME,
 							mdt_getattr_name),
@@ -5347,6 +5435,7 @@ int mdt_links_read(struct mdt_thread_info *info, struct mdt_object *mdt_obj,
  * \param[in]     info  Per-thread common data shared by MDT level handlers.
  * \param[in]     obj   Object to do path lookup of
  * \param[in,out] fp    User-provided struct to store path information
+ * \param[in]     root_fid Root FID of current path should reach
  *
  * \retval 0 Lookup successful, path information stored in fp
  * \retval -EAGAIN Lookup failed, usually because object is being moved
@@ -5354,7 +5443,8 @@ int mdt_links_read(struct mdt_thread_info *info, struct mdt_object *mdt_obj,
  */
 static int mdt_path_current(struct mdt_thread_info *info,
 			    struct mdt_object *obj,
-			    struct getinfo_fid2path *fp)
+			    struct getinfo_fid2path *fp,
+			    struct lu_fid *root_fid)
 {
 	struct mdt_device	*mdt = info->mti_mdt;
 	struct mdt_object	*mdt_obj;
@@ -5377,16 +5467,18 @@ static int mdt_path_current(struct mdt_thread_info *info,
 		RETURN(-ENOMEM);
 
 	ldata.ld_buf = buf;
-	ptr = fp->gf_path + fp->gf_pathlen - 1;
+	ptr = fp->gf_u.gf_path + fp->gf_pathlen - 1;
 	*ptr = 0;
 	--ptr;
 	*tmpfid = fp->gf_fid = *mdt_object_fid(obj);
 
-	/* root FID only exists on MDT0, and fid2path should also ends at MDT0,
-	 * so checking root_fid can only happen on MDT0. */
-	while (!lu_fid_eq(&mdt->mdt_md_root_fid, &fp->gf_fid)) {
+	while (!lu_fid_eq(root_fid, &fp->gf_fid)) {
 		struct lu_buf		lmv_buf;
 
+		if (!lu_fid_eq(root_fid, &mdt->mdt_md_root_fid) &&
+		    lu_fid_eq(&mdt->mdt_md_root_fid, &fp->gf_fid))
+			GOTO(out, rc = -ENOENT);
+
 		mdt_obj = mdt_object_find(info->mti_env, mdt, tmpfid);
 		if (IS_ERR(mdt_obj))
 			GOTO(out, rc = PTR_ERR(mdt_obj));
@@ -5447,7 +5539,7 @@ static int mdt_path_current(struct mdt_thread_info *info,
 
 		/* Pack the name in the end of the buffer */
 		ptr -= tmpname->ln_namelen;
-		if (ptr - 1 <= fp->gf_path)
+		if (ptr - 1 <= fp->gf_u.gf_path)
 			GOTO(out, rc = -EOVERFLOW);
 		strncpy(ptr, tmpname->ln_name, tmpname->ln_namelen);
 		*(--ptr) = '/';
@@ -5462,7 +5554,8 @@ static int mdt_path_current(struct mdt_thread_info *info,
 
 remote_out:
 	ptr++; /* skip leading / */
-	memmove(fp->gf_path, ptr, fp->gf_path + fp->gf_pathlen - ptr);
+	memmove(fp->gf_u.gf_path, ptr,
+		fp->gf_u.gf_path + fp->gf_pathlen - ptr);
 
 out:
 	RETURN(rc);
@@ -5484,7 +5577,7 @@ out:
  * \retval negative errno if there was a problem
  */
 static int mdt_path(struct mdt_thread_info *info, struct mdt_object *obj,
-		    struct getinfo_fid2path *fp)
+		    struct getinfo_fid2path *fp, struct lu_fid *root_fid)
 {
 	struct mdt_device	*mdt = info->mti_mdt;
 	int			tries = 3;
@@ -5494,14 +5587,17 @@ static int mdt_path(struct mdt_thread_info *info, struct mdt_object *obj,
 	if (fp->gf_pathlen < 3)
 		RETURN(-EOVERFLOW);
 
-	if (lu_fid_eq(&mdt->mdt_md_root_fid, mdt_object_fid(obj))) {
-		fp->gf_path[0] = '\0';
+	if (root_fid == NULL)
+		root_fid = &mdt->mdt_md_root_fid;
+
+	if (lu_fid_eq(root_fid, mdt_object_fid(obj))) {
+		fp->gf_u.gf_path[0] = '\0';
 		RETURN(0);
 	}
 
 	/* Retry multiple times in case file is being moved */
 	while (tries-- && rc == -EAGAIN)
-		rc = mdt_path_current(info, obj, fp);
+		rc = mdt_path_current(info, obj, fp, root_fid);
 
 	RETURN(rc);
 }
@@ -5523,6 +5619,7 @@ static int mdt_path(struct mdt_thread_info *info, struct mdt_object *obj,
  * \retval negative errno if there was a problem
  */
 static int mdt_fid2path(struct mdt_thread_info *info,
+			struct lu_fid *root_fid,
 			struct getinfo_fid2path *fp)
 {
 	struct mdt_device *mdt = info->mti_mdt;
@@ -5565,20 +5662,22 @@ static int mdt_fid2path(struct mdt_thread_info *info,
 		RETURN(rc);
 	}
 
-	rc = mdt_path(info, obj, fp);
+	rc = mdt_path(info, obj, fp, root_fid);
 
 	CDEBUG(D_INFO, "fid "DFID", path %s recno "LPX64" linkno %u\n",
-	       PFID(&fp->gf_fid), fp->gf_path, fp->gf_recno, fp->gf_linkno);
+	       PFID(&fp->gf_fid), fp->gf_u.gf_path,
+	       fp->gf_recno, fp->gf_linkno);
 
 	mdt_object_put(info->mti_env, obj);
 
 	RETURN(rc);
 }
 
-static int mdt_rpc_fid2path(struct mdt_thread_info *info, void *key,
+static int mdt_rpc_fid2path(struct mdt_thread_info *info, void *key, int keylen,
 			    void *val, int vallen)
 {
 	struct getinfo_fid2path *fpout, *fpin;
+	struct lu_fid *root_fid = NULL;
 	int rc = 0;
 
 	fpin = key + cfs_size_round(sizeof(KEY_FID2PATH));
@@ -5591,7 +5690,18 @@ static int mdt_rpc_fid2path(struct mdt_thread_info *info, void *key,
 	if (fpout->gf_pathlen != vallen - sizeof(*fpin))
 		RETURN(-EINVAL);
 
-	rc = mdt_fid2path(info, fpout);
+	if (keylen >= cfs_size_round(sizeof(KEY_FID2PATH)) + sizeof(*fpin) +
+		      sizeof(struct lu_fid)) {
+		/* client sent its root FID, which is normally fileset FID */
+		root_fid = fpin->gf_u.gf_root_fid;
+		if (ptlrpc_req_need_swab(info->mti_pill->rc_req))
+			lustre_swab_lu_fid(root_fid);
+
+		if (root_fid != NULL && !fid_is_sane(root_fid))
+			RETURN(-EINVAL);
+	}
+
+	rc = mdt_fid2path(info, root_fid, fpout);
 	RETURN(rc);
 }
 
@@ -5636,7 +5746,7 @@ int mdt_get_info(struct tgt_session_info *tsi)
 	if (KEY_IS(KEY_FID2PATH)) {
 		struct mdt_thread_info	*info = tsi2mdt_info(tsi);
 
-		rc = mdt_rpc_fid2path(info, key, valout, *vallen);
+		rc = mdt_rpc_fid2path(info, key, keylen, valout, *vallen);
 		mdt_thread_info_fini(info);
 	} else {
 		rc = -EINVAL;
diff --git a/lustre/obdclass/lprocfs_status.c b/lustre/obdclass/lprocfs_status.c
index 18f383b..cce0628 100644
--- a/lustre/obdclass/lprocfs_status.c
+++ b/lustre/obdclass/lprocfs_status.c
@@ -657,7 +657,7 @@ static const char *obd_connect_names[] = {
 	"unlink_close",
 	"multi_mod_rpcs",
 	"dir_stripe",
-	"fileset_mount",
+	"subtree",
 	"lock_ahead",
 	"bulk_mbits",
 	"compact_obdo",
diff --git a/lustre/obdclass/obd_mount.c b/lustre/obdclass/obd_mount.c
index 153986a..6b1ae94 100644
--- a/lustre/obdclass/obd_mount.c
+++ b/lustre/obdclass/obd_mount.c
@@ -593,32 +593,35 @@ static struct lustre_sb_info *lustre_init_lsi(struct super_block *sb)
 
 static int lustre_free_lsi(struct super_block *sb)
 {
-        struct lustre_sb_info *lsi = s2lsi(sb);
-        ENTRY;
+	struct lustre_sb_info *lsi = s2lsi(sb);
+	ENTRY;
 
-        LASSERT(lsi != NULL);
-        CDEBUG(D_MOUNT, "Freeing lsi %p\n", lsi);
+	LASSERT(lsi != NULL);
+	CDEBUG(D_MOUNT, "Freeing lsi %p\n", lsi);
 
-        /* someone didn't call server_put_mount. */
+	/* someone didn't call server_put_mount. */
 	LASSERT(atomic_read(&lsi->lsi_mounts) == 0);
 
-        if (lsi->lsi_lmd != NULL) {
-                if (lsi->lsi_lmd->lmd_dev != NULL)
-                        OBD_FREE(lsi->lsi_lmd->lmd_dev,
-                                 strlen(lsi->lsi_lmd->lmd_dev) + 1);
-                if (lsi->lsi_lmd->lmd_profile != NULL)
-                        OBD_FREE(lsi->lsi_lmd->lmd_profile,
-                                 strlen(lsi->lsi_lmd->lmd_profile) + 1);
-                if (lsi->lsi_lmd->lmd_mgssec != NULL)
-                        OBD_FREE(lsi->lsi_lmd->lmd_mgssec,
-                                 strlen(lsi->lsi_lmd->lmd_mgssec) + 1);
-                if (lsi->lsi_lmd->lmd_opts != NULL)
-                        OBD_FREE(lsi->lsi_lmd->lmd_opts,
-                                 strlen(lsi->lsi_lmd->lmd_opts) + 1);
-                if (lsi->lsi_lmd->lmd_exclude_count)
-                        OBD_FREE(lsi->lsi_lmd->lmd_exclude,
-                                 sizeof(lsi->lsi_lmd->lmd_exclude[0]) *
-                                 lsi->lsi_lmd->lmd_exclude_count);
+	if (lsi->lsi_lmd != NULL) {
+		if (lsi->lsi_lmd->lmd_dev != NULL)
+			OBD_FREE(lsi->lsi_lmd->lmd_dev,
+				strlen(lsi->lsi_lmd->lmd_dev) + 1);
+		if (lsi->lsi_lmd->lmd_profile != NULL)
+			OBD_FREE(lsi->lsi_lmd->lmd_profile,
+				strlen(lsi->lsi_lmd->lmd_profile) + 1);
+		if (lsi->lsi_lmd->lmd_fileset != NULL)
+			OBD_FREE(lsi->lsi_lmd->lmd_fileset,
+				strlen(lsi->lsi_lmd->lmd_fileset) + 1);
+		if (lsi->lsi_lmd->lmd_mgssec != NULL)
+			OBD_FREE(lsi->lsi_lmd->lmd_mgssec,
+				strlen(lsi->lsi_lmd->lmd_mgssec) + 1);
+		if (lsi->lsi_lmd->lmd_opts != NULL)
+			OBD_FREE(lsi->lsi_lmd->lmd_opts,
+				strlen(lsi->lsi_lmd->lmd_opts) + 1);
+		if (lsi->lsi_lmd->lmd_exclude_count)
+			OBD_FREE(lsi->lsi_lmd->lmd_exclude,
+				sizeof(lsi->lsi_lmd->lmd_exclude[0]) *
+				lsi->lsi_lmd->lmd_exclude_count);
 		if (lsi->lsi_lmd->lmd_mgs != NULL)
 			OBD_FREE(lsi->lsi_lmd->lmd_mgs,
 				 strlen(lsi->lsi_lmd->lmd_mgs) + 1);
@@ -628,14 +631,14 @@ static int lustre_free_lsi(struct super_block *sb)
 		if (lsi->lsi_lmd->lmd_params != NULL)
 			OBD_FREE(lsi->lsi_lmd->lmd_params, 4096);
 
-                OBD_FREE(lsi->lsi_lmd, sizeof(*lsi->lsi_lmd));
-        }
+		OBD_FREE_PTR(lsi->lsi_lmd);
+	}
 
-        LASSERT(lsi->lsi_llsbi == NULL);
-        OBD_FREE(lsi, sizeof(*lsi));
-        s2lsi_nocast(sb) = NULL;
+	LASSERT(lsi->lsi_llsbi == NULL);
+	OBD_FREE_PTR(lsi);
+	s2lsi_nocast(sb) = NULL;
 
-        RETURN(0);
+	RETURN(0);
 }
 
 /* The lsi has one reference for every server that is using the disk -
@@ -1298,18 +1301,39 @@ static int lmd_parse(char *options, struct lustre_mount_data *lmd)
                 goto invalid;
         }
 
-        s1 = strstr(devname, ":/");
-        if (s1) {
-                ++s1;
-                lmd->lmd_flags |= LMD_FLG_CLIENT;
-                /* Remove leading /s from fsname */
-                while (*++s1 == '/') ;
-                /* Freed in lustre_free_lsi */
-                OBD_ALLOC(lmd->lmd_profile, strlen(s1) + 8);
-                if (!lmd->lmd_profile)
-                        RETURN(-ENOMEM);
-                sprintf(lmd->lmd_profile, "%s-client", s1);
-        }
+	s1 = strstr(devname, ":/");
+	if (s1) {
+		++s1;
+		lmd->lmd_flags |= LMD_FLG_CLIENT;
+		/* Remove leading /s from fsname */
+		while (*++s1 == '/')
+			;
+		s2 = s1;
+		while (*s2 != '/' && *s2 != '\0')
+			s2++;
+		/* Freed in lustre_free_lsi */
+		OBD_ALLOC(lmd->lmd_profile, s2 - s1 + 8);
+		if (!lmd->lmd_profile)
+			RETURN(-ENOMEM);
+
+		strncat(lmd->lmd_profile, s1, s2 - s1);
+		strncat(lmd->lmd_profile, "-client", 7);
+
+		s1 = s2;
+		s2 = s1 + strlen(s1) - 1;
+		/* Remove padding /s from fileset */
+		while (*s2 == '/')
+			s2--;
+		if (s2 > s1) {
+			OBD_ALLOC(lmd->lmd_fileset, s2 - s1 + 2);
+			if (lmd->lmd_fileset == NULL) {
+				OBD_FREE(lmd->lmd_profile,
+					strlen(lmd->lmd_profile) + 1);
+				RETURN(-ENOMEM);
+			}
+			strncat(lmd->lmd_fileset, s1, s2 - s1 + 1);
+		}
+	}
 
         /* Freed in lustre_free_lsi */
         OBD_ALLOC(lmd->lmd_dev, strlen(devname) + 1);
@@ -1381,28 +1405,28 @@ static int lustre_fill_super(struct super_block *sb, void *data, int silent)
                 GOTO(out, rc = -EINVAL);
         }
 
-        if (lmd_is_client(lmd)) {
-                CDEBUG(D_MOUNT, "Mounting client %s\n", lmd->lmd_profile);
+	if (lmd_is_client(lmd)) {
+		CDEBUG(D_MOUNT, "Mounting client %s\n", lmd->lmd_profile);
 		if (client_fill_super == NULL)
 			request_module("lustre");
 		if (client_fill_super == NULL) {
-                        LCONSOLE_ERROR_MSG(0x165, "Nothing registered for "
-                                           "client mount! Is the 'lustre' "
-                                           "module loaded?\n");
-                        lustre_put_lsi(sb);
-                        rc = -ENODEV;
-                } else {
-                        rc = lustre_start_mgc(sb);
-                        if (rc) {
-                                lustre_put_lsi(sb);
-                                GOTO(out, rc);
-                        }
-                        /* Connect and start */
-                        /* (should always be ll_fill_super) */
-                        rc = (*client_fill_super)(sb, lmd2->lmd2_mnt);
-                        /* c_f_s will call lustre_common_put_super on failure */
-                }
-        } else {
+			LCONSOLE_ERROR_MSG(0x165, "Nothing registered for "
+					   "client mount! Is the 'lustre' "
+					   "module loaded?\n");
+			lustre_put_lsi(sb);
+			rc = -ENODEV;
+		} else {
+			rc = lustre_start_mgc(sb);
+			if (rc) {
+				lustre_put_lsi(sb);
+				GOTO(out, rc);
+			}
+			/* Connect and start */
+			/* (should always be ll_fill_super) */
+			rc = (*client_fill_super)(sb, lmd2->lmd2_mnt);
+			/* c_f_s will call lustre_common_put_super on failure */
+		}
+	} else {
 #ifdef HAVE_SERVER_SUPPORT
 		CDEBUG(D_MOUNT, "Mounting server from %s\n", lmd->lmd_dev);
 		rc = server_fill_super(sb);
@@ -1415,7 +1439,7 @@ static int lustre_fill_super(struct super_block *sb, void *data, int silent)
 		       "cannot handle server mount.\n");
 		rc = -EINVAL;
 #endif
-        }
+	}
 
         /* If error happens in fill_super() call, @lsi will be killed there.
          * This is why we do not put it here. */
diff --git a/lustre/ptlrpc/layout.c b/lustre/ptlrpc/layout.c
index 8a4933d..111d1d1 100644
--- a/lustre/ptlrpc/layout.c
+++ b/lustre/ptlrpc/layout.c
@@ -501,6 +501,12 @@ static const struct req_msg_field *ldlm_intent_getxattr_server[] = {
 	&RMF_EAVALS_LENS
 };
 
+static const struct req_msg_field *mds_get_root_client[] = {
+	&RMF_PTLRPC_BODY,
+	&RMF_MDT_BODY,
+	&RMF_NAME
+};
+
 static const struct req_msg_field *mds_getxattr_client[] = {
         &RMF_PTLRPC_BODY,
         &RMF_MDT_BODY,
@@ -731,7 +737,7 @@ static struct req_format *req_formats[] = {
         &RQF_MDS_CONNECT,
         &RQF_MDS_DISCONNECT,
         &RQF_MDS_GET_INFO,
-        &RQF_MDS_GETSTATUS,
+	&RQF_MDS_GET_ROOT,
         &RQF_MDS_STATFS,
         &RQF_MDS_GETATTR,
         &RQF_MDS_GETATTR_NAME,
@@ -1328,9 +1334,9 @@ struct req_format RQF_LDLM_INTENT_QUOTA =
 			ldlm_intent_quota_server);
 EXPORT_SYMBOL(RQF_LDLM_INTENT_QUOTA);
 
-struct req_format RQF_MDS_GETSTATUS =
-        DEFINE_REQ_FMT0("MDS_GETSTATUS", mdt_body_only, mdt_body_capa);
-EXPORT_SYMBOL(RQF_MDS_GETSTATUS);
+struct req_format RQF_MDS_GET_ROOT =
+	DEFINE_REQ_FMT0("MDS_GET_ROOT", mds_get_root_client, mdt_body_capa);
+EXPORT_SYMBOL(RQF_MDS_GET_ROOT);
 
 struct req_format RQF_MDS_STATFS =
         DEFINE_REQ_FMT0("MDS_STATFS", empty, obd_statfs_server);
diff --git a/lustre/ptlrpc/lproc_ptlrpc.c b/lustre/ptlrpc/lproc_ptlrpc.c
index 255c9f5..1920fc7 100644
--- a/lustre/ptlrpc/lproc_ptlrpc.c
+++ b/lustre/ptlrpc/lproc_ptlrpc.c
@@ -78,7 +78,7 @@ static struct ll_rpc_opcode {
         { MDS_READPAGE,     "mds_readpage" },
         { MDS_CONNECT,      "mds_connect" },
         { MDS_DISCONNECT,   "mds_disconnect" },
-        { MDS_GETSTATUS,    "mds_getstatus" },
+	{ MDS_GET_ROOT,     "mds_get_root" },
         { MDS_STATFS,       "mds_statfs" },
         { MDS_PIN,          "mds_pin" },
         { MDS_UNPIN,        "mds_unpin" },
diff --git a/lustre/ptlrpc/wiretest.c b/lustre/ptlrpc/wiretest.c
index a8f52f8..33ea7b1 100644
--- a/lustre/ptlrpc/wiretest.c
+++ b/lustre/ptlrpc/wiretest.c
@@ -134,8 +134,8 @@ void lustre_assert_wire_constants(void)
 		 (long long)MDS_CONNECT);
 	LASSERTF(MDS_DISCONNECT == 39, "found %lld\n",
 		 (long long)MDS_DISCONNECT);
-	LASSERTF(MDS_GETSTATUS == 40, "found %lld\n",
-		 (long long)MDS_GETSTATUS);
+	LASSERTF(MDS_GET_ROOT == 40, "found %lld\n",
+		 (long long)MDS_GET_ROOT);
 	LASSERTF(MDS_STATFS == 41, "found %lld\n",
 		 (long long)MDS_STATFS);
 	LASSERTF(MDS_PIN == 42, "found %lld\n",
@@ -4068,10 +4068,10 @@ void lustre_assert_wire_constants(void)
 		 (long long)(int)offsetof(struct getinfo_fid2path, gf_pathlen));
 	LASSERTF((int)sizeof(((struct getinfo_fid2path *)0)->gf_pathlen) == 4, "found %lld\n",
 		 (long long)(int)sizeof(((struct getinfo_fid2path *)0)->gf_pathlen));
-	LASSERTF((int)offsetof(struct getinfo_fid2path, gf_path[0]) == 32, "found %lld\n",
-		 (long long)(int)offsetof(struct getinfo_fid2path, gf_path[0]));
-	LASSERTF((int)sizeof(((struct getinfo_fid2path *)0)->gf_path[0]) == 1, "found %lld\n",
-		 (long long)(int)sizeof(((struct getinfo_fid2path *)0)->gf_path[0]));
+	LASSERTF((int)offsetof(struct getinfo_fid2path, gf_u.gf_path[0]) == 32, "found %lld\n",
+		 (long long)(int)offsetof(struct getinfo_fid2path, gf_u.gf_path[0]));
+	LASSERTF((int)sizeof(((struct getinfo_fid2path *)0)->gf_u.gf_path[0]) == 1, "found %lld\n",
+		 (long long)(int)sizeof(((struct getinfo_fid2path *)0)->gf_u.gf_path[0]));
 
 	/* Checks for struct fiemap */
 	LASSERTF((int)sizeof(struct fiemap) == 32, "found %lld\n",
diff --git a/lustre/tests/cfg/local.sh b/lustre/tests/cfg/local.sh
index 85f6644..d9d0ce2 100644
--- a/lustre/tests/cfg/local.sh
+++ b/lustre/tests/cfg/local.sh
@@ -7,6 +7,10 @@ mgs_HOST=${mgs_HOST:-$mds_HOST}
 ost_HOST=${ost_HOST:-$(hostname)}
 ostfailover_HOST=${ostfailover_HOST}
 CLIENTS=""
+# FILESET variable is used by sanity.sh to verify fileset
+# feature, tests should pass even under subdirectory namespace.
+FILESET=${FILESET:-""}
+[[ -z "$FILESET" ]] || [[ "${FILESET:0:1}" = "/" ]] || FILESET="/$FILESET"
 
 TMP=${TMP:-/tmp}
 
diff --git a/lustre/tests/sanity.sh b/lustre/tests/sanity.sh
old mode 100755
new mode 100644
index 21b7f1e..8a96be6
--- a/lustre/tests/sanity.sh
+++ b/lustre/tests/sanity.sh
@@ -105,7 +105,6 @@ check_swap_layouts_support()
 }
 
 check_and_setup_lustre
-
 DIR=${DIR:-$MOUNT}
 assert_DIR
 
@@ -2020,6 +2019,7 @@ run_test 27C "check full striping across all OSTs"
 
 test_27D() {
 	[ $OSTCOUNT -lt 2 ] && skip "needs >= 2 OSTs" && return
+	[ -n "$FILESET" ] && skip "SKIP due to FILESET set" && return
 	local POOL=${POOL:-testpool}
 	local first_ost=0
 	local last_ost=$(($OSTCOUNT - 1))
@@ -9946,6 +9946,7 @@ test_154a() {
 	[[ $(lustre_version_code $SINGLEMDS) -ge $(version_code 2.2.51) ]] ||
 		{ skip "Need MDS version at least 2.2.51"; return 0; }
 	[ -z "$(which setfacl)" ] && skip "must have setfacl tool" && return
+	[ -n "$FILESET" ] && skip "SKIP due to FILESET set" && return
 
 	cp /etc/hosts $DIR/$tfile
 
@@ -9972,6 +9973,7 @@ test_154b() {
 	[ $PARALLEL == "yes" ] && skip "skip parallel run" && return
 	[[ $(lustre_version_code $SINGLEMDS) -ge $(version_code 2.2.51) ]] ||
 		{ skip "Need MDS version at least 2.2.51"; return 0; }
+	[ -n "$FILESET" ] && skip "SKIP due to FILESET set" && return
 
 	[ $MDSCOUNT -lt 2 ] && skip "needs >= 2 MDTs" && return
 
@@ -10068,6 +10070,7 @@ test_154e()
 run_test 154e ".lustre is not returned by readdir"
 
 test_154f() {
+	[ -n "$FILESET" ] && skip "SKIP due to FILESET set" && return
 	# create parent directory on a single MDT to avoid cross-MDT hardlinks
 	test_mkdir -p -c1 $DIR/$tdir/d
 	# test dirs inherit from its stripe
@@ -10147,6 +10150,7 @@ test_154g()
 {
 	[[ $(lustre_version_code $SINGLEMDS) -ge $(version_code 2.6.92) ]] ||
 		{ skip "Need MDS version at least 2.6.92"; return 0; }
+	[ -n "$FILESET" ] && skip "SKIP due to FILESET set" && return
 
 	mkdir -p $DIR/$tdir
 	llapi_fid_test -d $DIR/$tdir
@@ -11435,6 +11439,7 @@ test_185() { # LU-2441
 	local mtime1=$(stat -c "%Y" $DIR/$tdir)
 	local fid=$($MULTIOP $DIR/$tdir VFw4096c) ||
 		error "cannot create/write a volatile file"
+	[ "$FILESET" == "" ] &&
 	$CHECKSTAT -t file $MOUNT/.lustre/fid/$fid 2>/dev/null &&
 		error "FID is still valid after close"
 
@@ -11449,8 +11454,10 @@ test_185() { # LU-2441
 	# is unfortunately eaten by multiop_bg_pause
 	local n=$((${fidv[1]} + 1))
 	local next_fid="${fidv[0]}:$(printf "0x%x" $n):${fidv[2]}"
-	$CHECKSTAT -t file $MOUNT/.lustre/fid/$next_fid ||
-		error "FID is missing before close"
+	if [ "$FILESET" == "" ]; then
+		$CHECKSTAT -t file $MOUNT/.lustre/fid/$next_fid ||
+			error "FID is missing before close"
+	fi
 	kill -USR1 $multi_pid
 	# 1 second delay, so if mtime change we will see it
 	sleep 1
@@ -11501,6 +11508,7 @@ run_test 187b "Test data version change on volatile file"
 test_200() {
 	[ $PARALLEL == "yes" ] && skip "skip parallel run" && return
 	remote_mgs_nodsh && skip "remote MGS with nodsh" && return
+	[ -n "$FILESET" ] && skip "SKIP due to FILESET set" && return
 
 	local POOL=${POOL:-cea1}
 	local POOL_ROOT=${POOL_ROOT:-$DIR/d200.pools}
@@ -13197,6 +13205,7 @@ run_test 232 "failed lock should not block umount"
 test_233a() {
 	[ $(lustre_version_code $SINGLEMDS) -ge $(version_code 2.3.64) ] ||
 	{ skip "Need MDS version at least 2.3.64"; return; }
+	[ -n "$FILESET" ] && skip "SKIP due to FILESET set" && return
 
 	local fid=$($LFS path2fid $MOUNT)
 	stat $MOUNT/.lustre/fid/$fid > /dev/null ||
@@ -13207,6 +13216,7 @@ run_test 233a "checking that OBF of the FS root succeeds"
 test_233b() {
 	[ $(lustre_version_code $SINGLEMDS) -ge $(version_code 2.5.90) ] ||
 	{ skip "Need MDS version at least 2.5.90"; return; }
+	[ -n "$FILESET" ] && skip "SKIP due to FILESET set" && return
 
 	local fid=$($LFS path2fid $MOUNT/.lustre)
 	stat $MOUNT/.lustre/fid/$fid > /dev/null ||
@@ -13488,6 +13498,74 @@ test_246() { # LU-7371
 }
 run_test 246 "Read file of size 4095 should return right length"
 
+test_247a() {
+	lctl get_param -n mdc.$FSNAME-MDT0000*.import |
+		grep -q subtree ||
+		{ skip "Fileset feature is not supported"; return; }
+
+	local submount=${MOUNT}_$tdir
+
+	mkdir $MOUNT/$tdir
+	mkdir -p $submount || error "mkdir $submount failed"
+	FILESET="$FILESET/$tdir" mount_client $submount ||
+		error "mount $submount failed"
+	echo foo > $submount/$tfile || error "write $submount/$tfile failed"
+	[ $(cat $MOUNT/$tdir/$tfile) = "foo" ] ||
+		error "read $MOUNT/$tdir/$tfile failed"
+	umount_client $submount || error "umount $submount failed"
+	rmdir $submount
+}
+run_test 247a "mount subdir as fileset"
+
+test_247b() {
+	lctl get_param -n mdc.$FSNAME-MDT0000*.import | grep -q subtree ||
+		{ skip "Fileset feature is not supported"; return; }
+
+	local submount=${MOUNT}_$tdir
+
+	rm -rf $MOUNT/$tdir
+	mkdir -p $submount || error "mkdir $submount failed"
+	SKIP_FILESET=1
+	FILESET="$FILESET/$tdir" mount_client $submount &&
+		error "mount $submount should fail"
+	rmdir $submount
+}
+run_test 247b "mount subdir that dose not exist"
+
+test_247c() {
+	lctl get_param -n mdc.$FSNAME-MDT0000*.import | grep -q subtree ||
+		{ skip "Fileset feature is not supported"; return; }
+
+	local submount=${MOUNT}_$tdir
+
+	mkdir -p $MOUNT/$tdir/dir1
+	mkdir -p $submount || error "mkdir $submount failed"
+	FILESET="$FILESET/$tdir" mount_client $submount ||
+		error "mount $submount failed"
+	local fid=$($LFS path2fid $MOUNT/)
+	$LFS fid2path $submount $fid && error "fid2path should fail"
+	umount_client $submount || error "umount $submount failed"
+	rmdir $submount
+}
+run_test 247c "running fid2path outside root"
+
+test_247d() {
+	lctl get_param -n mdc.$FSNAME-MDT0000*.import | grep -q subtree ||
+		{ skip "Fileset feature is not supported"; return; }
+
+	local submount=${MOUNT}_$tdir
+
+	mkdir -p $MOUNT/$tdir/dir1
+	mkdir -p $submount || error "mkdir $submount failed"
+	FILESET="$FILESET/$tdir" mount_client $submount ||
+		error "mount $submount failed"
+	local fid=$($LFS path2fid $submount/dir1)
+	$LFS fid2path $submount $fid || error "fid2path should succeed"
+	umount_client $submount || error "umount $submount failed"
+	rmdir $submount
+}
+run_test 247d "running fid2path inside root"
+
 test_250() {
 	[ "$(facet_fstype ost$(($($GETSTRIPE -i $DIR/$tfile) + 1)))" = "zfs" ] \
 	 && skip "no 16TB file size limit on ZFS" && return
diff --git a/lustre/tests/test-framework.sh b/lustre/tests/test-framework.sh
index 24790da..c413a35 100755
--- a/lustre/tests/test-framework.sh
+++ b/lustre/tests/test-framework.sh
@@ -1499,25 +1499,37 @@ setup_quota(){
 }
 
 zconf_mount() {
-    local client=$1
-    local mnt=$2
-    local opts=${3:-$MOUNT_OPTS}
-    opts=${opts:+-o $opts}
-    local flags=${4:-$MOUNT_FLAGS}
-
-    local device=$MGSNID:/$FSNAME
-    if [ -z "$mnt" -o -z "$FSNAME" ]; then
-        echo Bad zconf mount command: opt=$flags $opts dev=$device mnt=$mnt
-        exit 1
-    fi
+	local client=$1
+	local mnt=$2
+	local opts=${3:-$MOUNT_OPTS}
+	opts=${opts:+-o $opts}
+	local flags=${4:-$MOUNT_FLAGS}
+
+	local device=$MGSNID:/$FSNAME$FILESET
+	if [ -z "$mnt" -o -z "$FSNAME" ]; then
+		echo "Bad mount command: opt=$flags $opts dev=$device " \
+		     "mnt=$mnt"
+		exit 1
+	fi
+
+	echo "Starting client: $client: $flags $opts $device $mnt"
+	do_node $client mkdir -p $mnt
+	if [ -n "$FILESET" -a -z "$SKIP_FILESET" ];then
+		do_node $client $MOUNT_CMD $flags $opts $MGSNID:/$FSNAME \
+			$mnt || return 1
+		#disable FILESET if not supported
+		do_nodes $client lctl get_param -n \
+			mdc.$FSNAME-MDT0000*.import | grep -q subtree ||
+				device=$MGSNID:/$FSNAME
+		do_node $client mkdir -p $mnt/$FILESET
+		do_node $client "! grep -q $mnt' ' /proc/mounts ||
+			umount $mnt"
+	fi
+	do_node $client $MOUNT_CMD $flags $opts $device $mnt || return 1
+
+	set_default_debug_nodes $client
 
-    echo "Starting client: $client: $flags $opts $device $mnt"
-    do_node $client mkdir -p $mnt
-    do_node $client $MOUNT_CMD $flags $opts $device $mnt || return 1
-
-    set_default_debug_nodes $client
-
-    return 0
+	return 0
 }
 
 zconf_umount() {
@@ -1607,21 +1619,35 @@ sanity_mount_check () {
 
 # mount clients if not mouted
 zconf_mount_clients() {
-    local clients=$1
-    local mnt=$2
-    local opts=${3:-$MOUNT_OPTS}
-    opts=${opts:+-o $opts}
-    local flags=${4:-$MOUNT_FLAGS}
-
-    local device=$MGSNID:/$FSNAME
-    if [ -z "$mnt" -o -z "$FSNAME" ]; then
-        echo Bad zconf mount command: opt=$flags $opts dev=$device mnt=$mnt
-        exit 1
-    fi
-
-    echo "Starting client $clients: $flags $opts $device $mnt"
-
-    do_nodes $clients "
+	local clients=$1
+	local mnt=$2
+	local opts=${3:-$MOUNT_OPTS}
+	opts=${opts:+-o $opts}
+	local flags=${4:-$MOUNT_FLAGS}
+
+	local device=$MGSNID:/$FSNAME$FILESET
+	if [ -z "$mnt" -o -z "$FSNAME" ]; then
+		echo "Bad conf mount command: opt=$flags $opts dev=$device " \
+		     "mnt=$mnt"
+		exit 1
+	fi
+
+	echo "Starting client $clients: $flags $opts $device $mnt"
+	if [ -n "$FILESET" -a ! -n "$SKIP_FILESET" ]; then
+		do_nodes $clients "! grep -q $mnt' ' /proc/mounts ||
+			umount $mnt"
+		do_nodes $clients $MOUNT_CMD $flags $opts $MGSNID:/$FSNAME \
+			$mnt || return 1
+		#disable FILESET if not supported
+		do_nodes $clients lctl get_param -n \
+			mdc.$FSNAME-MDT0000*.import | grep -q subtree ||
+				device=$MGSNID:/$FSNAME
+		do_nodes $clients mkdir -p $mnt/$FILESET
+		do_nodes $clients "! grep -q $mnt' ' /proc/mounts ||
+			umount $mnt"
+	fi
+
+	do_nodes $clients "
 running=\\\$(mount | grep -c $mnt' ');
 rc=0;
 if [ \\\$running -eq 0 ] ; then
@@ -1631,12 +1657,12 @@ if [ \\\$running -eq 0 ] ; then
 fi;
 exit \\\$rc" || return ${PIPESTATUS[0]}
 
-    echo "Started clients $clients: "
-    do_nodes $clients "mount | grep $mnt' '"
+	echo "Started clients $clients: "
+	do_nodes $clients "mount | grep $mnt' '"
 
-    set_default_debug_nodes $clients
+	set_default_debug_nodes $clients
 
-    return 0
+	return 0
 }
 
 zconf_umount_clients() {
diff --git a/lustre/utils/liblustreapi.c b/lustre/utils/liblustreapi.c
index 516af31..dd15d55 100644
--- a/lustre/utils/liblustreapi.c
+++ b/lustre/utils/liblustreapi.c
@@ -847,21 +847,21 @@ out:
  */
 int get_root_path(int want, char *fsname, int *outfd, char *path, int index)
 {
-        struct mntent mnt;
-        char buf[PATH_MAX], mntdir[PATH_MAX];
-        char *ptr;
-        FILE *fp;
-        int idx = 0, len = 0, mntlen, fd;
-        int rc = -ENODEV;
+	struct mntent mnt;
+	char buf[PATH_MAX], mntdir[PATH_MAX];
+	char *ptr, *ptr_end;
+	FILE *fp;
+	int idx = 0, len = 0, mntlen, fd;
+	int rc = -ENODEV;
 
         /* get the mount point */
-        fp = setmntent(PROC_MOUNTS, "r");
-        if (fp == NULL) {
-                rc = -EIO;
-                llapi_error(LLAPI_MSG_ERROR, rc,
+	fp = setmntent(PROC_MOUNTS, "r");
+	if (fp == NULL) {
+		rc = -EIO;
+		llapi_error(LLAPI_MSG_ERROR, rc,
                             "setmntent(%s) failed", PROC_MOUNTS);
-                return rc;
-        }
+		return rc;
+	}
         while (1) {
                 if (getmntent_r(fp, &mnt, buf, sizeof(buf)) == NULL)
                         break;
@@ -873,58 +873,71 @@ int get_root_path(int want, char *fsname, int *outfd, char *path, int index)
                         continue;
 
                 mntlen = strlen(mnt.mnt_dir);
-                ptr = strrchr(mnt.mnt_fsname, '/');
+		ptr = strchr(mnt.mnt_fsname, '/');
+		while (ptr && *ptr == '/')
+			ptr++;
 		/* thanks to the call to llapi_is_lustre_mnt() above,
 		 * we are sure that mnt.mnt_fsname contains ":/",
 		 * so ptr should never be NULL */
 		if (ptr == NULL)
 			continue;
-                ptr++;
+		ptr_end = ptr;
+		while (*ptr_end != '/' && *ptr_end != '\0')
+			ptr_end++;
 
-                /* Check the fsname for a match, if given */
+		/* Check the fsname for a match, if given */
                 if (!(want & WANT_FSNAME) && fsname != NULL &&
-                    (strlen(fsname) > 0) && (strcmp(ptr, fsname) != 0))
+		    (strlen(fsname) > 0) &&
+		    (strncmp(ptr, fsname, ptr_end - ptr) != 0))
                         continue;
 
                 /* If the path isn't set return the first one we find */
-                if (path == NULL || strlen(path) == 0) {
-                        strcpy(mntdir, mnt.mnt_dir);
-                        if ((want & WANT_FSNAME) && fsname != NULL)
-                                strcpy(fsname, ptr);
-                        rc = 0;
-                        break;
-                /* Otherwise find the longest matching path */
-                } else if ((strlen(path) >= mntlen) && (mntlen >= len) &&
-                           (strncmp(mnt.mnt_dir, path, mntlen) == 0)) {
-                        strcpy(mntdir, mnt.mnt_dir);
-                        len = mntlen;
-                        if ((want & WANT_FSNAME) && fsname != NULL)
-                                strcpy(fsname, ptr);
-                        rc = 0;
-                }
-        }
-        endmntent(fp);
+		if (path == NULL || strlen(path) == 0) {
+			strncpy(mntdir, mnt.mnt_dir, strlen(mnt.mnt_dir));
+			mntdir[strlen(mnt.mnt_dir)] = '\0';
+			if ((want & WANT_FSNAME) && fsname != NULL) {
+				strncpy(fsname, ptr, ptr_end - ptr);
+				fsname[ptr_end - ptr] = '\0';
+			}
+			rc = 0;
+			break;
+		/* Otherwise find the longest matching path */
+		} else if ((strlen(path) >= mntlen) && (mntlen >= len) &&
+			   (strncmp(mnt.mnt_dir, path, mntlen) == 0)) {
+			strncpy(mntdir, mnt.mnt_dir, strlen(mnt.mnt_dir));
+			mntdir[strlen(mnt.mnt_dir)] = '\0';
+			len = mntlen;
+			if ((want & WANT_FSNAME) && fsname != NULL) {
+				strncpy(fsname, ptr, ptr_end - ptr);
+				fsname[ptr_end - ptr] = '\0';
+			}
+			rc = 0;
+		}
+	}
+	endmntent(fp);
 
-        /* Found it */
-        if (rc == 0) {
-                if ((want & WANT_PATH) && path != NULL)
-                        strcpy(path, mntdir);
-                if (want & WANT_FD) {
-                        fd = open(mntdir, O_RDONLY | O_DIRECTORY | O_NONBLOCK);
-                        if (fd < 0) {
-                                rc = -errno;
-                                llapi_error(LLAPI_MSG_ERROR, rc,
-                                            "error opening '%s'", mntdir);
+	/* Found it */
+	if (rc == 0) {
+		if ((want & WANT_PATH) && path != NULL) {
+			strncpy(path, mntdir, strlen(mntdir));
+			path[strlen(mntdir)] = '\0';
+		}
+		if (want & WANT_FD) {
+			fd = open(mntdir, O_RDONLY | O_DIRECTORY | O_NONBLOCK);
+			if (fd < 0) {
+				rc = -errno;
+				llapi_error(LLAPI_MSG_ERROR, rc,
+					    "error opening '%s'", mntdir);
 
-                        } else {
-                                *outfd = fd;
-                        }
-                }
-        } else if (want & WANT_ERROR)
-                llapi_err_noerrno(LLAPI_MSG_ERROR,
-                                  "can't find fs root for '%s': %d",
-                                  (want & WANT_PATH) ? fsname : path, rc);
-        return rc;
+			} else {
+				*outfd = fd;
+			}
+		}
+	} else if (want & WANT_ERROR)
+		llapi_err_noerrno(LLAPI_MSG_ERROR,
+				  "can't find fs root for '%s': %d",
+				  (want & WANT_PATH) ? fsname : path, rc);
+	return rc;
 }
 
 /*
@@ -3889,9 +3902,6 @@ int root_ioctl(const char *mdtname, int opc, void *data, int *mdtidxp,
                 rc = -errno;
         else
                 rc = 0;
-        if (rc && want_error)
-                llapi_error(LLAPI_MSG_ERROR, rc, "ioctl %d err %d", opc, rc);
-
         close(fd);
         return rc;
 }
@@ -4136,7 +4146,7 @@ int llapi_fid2path(const char *device, const char *fidstr, char *buf,
 		if (rc != -ENOENT)
 			llapi_error(LLAPI_MSG_ERROR, rc, "ioctl err %d", rc);
 	} else {
-		memcpy(buf, gf->gf_path, gf->gf_pathlen);
+		memcpy(buf, gf->gf_u.gf_path, gf->gf_pathlen);
 		if (buf[0] == '\0') { /* ROOT path */
 			buf[0] = '/';
 			buf[1] = '\0';
diff --git a/lustre/utils/mount_lustre.c b/lustre/utils/mount_lustre.c
index 66ddb21..dfa65f4 100644
--- a/lustre/utils/mount_lustre.c
+++ b/lustre/utils/mount_lustre.c
@@ -96,7 +96,7 @@ void usage(FILE *out)
 		progname);
 	fprintf(out,
 		"\t<device>: the disk device, or for a client:\n"
-		"\t\t<mgmtnid>[:<altmgtnid>...]:/<filesystem>-client\n"
+		"\t\t<mgsnid>[:<altmgsnid>...]:/<filesystem>[/<subdir>]\n"
 		"\t<filesystem>: name of the Lustre filesystem (e.g. lustre1)\n"
 		"\t<mountpt>: filesystem mountpoint (e.g. /mnt/lustre)\n"
 		"\t-f|--fake: fake mount (updates /etc/mtab)\n"
diff --git a/lustre/utils/wirecheck.c b/lustre/utils/wirecheck.c
index eabca64..9b65370 100644
--- a/lustre/utils/wirecheck.c
+++ b/lustre/utils/wirecheck.c
@@ -446,6 +446,14 @@ check_ptlrpc_body(void)
 	CHECK_VALUE_X(MSG_CONNECT_TRANSNO);
 }
 
+/* XXX README XXX:
+ * Please DO NOT add flag values here before first ensuring that this same
+ * flag value is not in use on some other branch.  Please clear any such
+ * changes with senior engineers before starting to use a new flag.  Then,
+ * submit a small patch against EVERY branch that ONLY adds the new flag,
+ * updates obd_connect_names[] for lprocfs_rd_connect_flags(), adds the
+ * flag to check_obd_connect_data(), and updates wiretests accordingly, so it
+ * can be approved and landed easily to reserve the flag for future use. */
 static void
 check_obd_connect_data(void)
 {
@@ -2442,7 +2450,7 @@ main(int argc, char **argv)
 	CHECK_VALUE(MDS_READPAGE);
 	CHECK_VALUE(MDS_CONNECT);
 	CHECK_VALUE(MDS_DISCONNECT);
-	CHECK_VALUE(MDS_GETSTATUS);
+	CHECK_VALUE(MDS_GET_ROOT);
 	CHECK_VALUE(MDS_STATFS);
 	CHECK_VALUE(MDS_PIN);
 	CHECK_VALUE(MDS_UNPIN);
diff --git a/lustre/utils/wiretest.c b/lustre/utils/wiretest.c
index fc031e4..f965bac 100644
--- a/lustre/utils/wiretest.c
+++ b/lustre/utils/wiretest.c
@@ -149,8 +149,8 @@ void lustre_assert_wire_constants(void)
 		 (long long)MDS_CONNECT);
 	LASSERTF(MDS_DISCONNECT == 39, "found %lld\n",
 		 (long long)MDS_DISCONNECT);
-	LASSERTF(MDS_GETSTATUS == 40, "found %lld\n",
-		 (long long)MDS_GETSTATUS);
+	LASSERTF(MDS_GET_ROOT == 40, "found %lld\n",
+		 (long long)MDS_GET_ROOT);
 	LASSERTF(MDS_STATFS == 41, "found %lld\n",
 		 (long long)MDS_STATFS);
 	LASSERTF(MDS_PIN == 42, "found %lld\n",
@@ -4083,10 +4083,10 @@ void lustre_assert_wire_constants(void)
 		 (long long)(int)offsetof(struct getinfo_fid2path, gf_pathlen));
 	LASSERTF((int)sizeof(((struct getinfo_fid2path *)0)->gf_pathlen) == 4, "found %lld\n",
 		 (long long)(int)sizeof(((struct getinfo_fid2path *)0)->gf_pathlen));
-	LASSERTF((int)offsetof(struct getinfo_fid2path, gf_path[0]) == 32, "found %lld\n",
-		 (long long)(int)offsetof(struct getinfo_fid2path, gf_path[0]));
-	LASSERTF((int)sizeof(((struct getinfo_fid2path *)0)->gf_path[0]) == 1, "found %lld\n",
-		 (long long)(int)sizeof(((struct getinfo_fid2path *)0)->gf_path[0]));
+	LASSERTF((int)offsetof(struct getinfo_fid2path, gf_u.gf_path[0]) == 32, "found %lld\n",
+		 (long long)(int)offsetof(struct getinfo_fid2path, gf_u.gf_path[0]));
+	LASSERTF((int)sizeof(((struct getinfo_fid2path *)0)->gf_u.gf_path[0]) == 1, "found %lld\n",
+		 (long long)(int)sizeof(((struct getinfo_fid2path *)0)->gf_u.gf_path[0]));
 
 	/* Checks for struct fiemap */
 	LASSERTF((int)sizeof(struct fiemap) == 32, "found %lld\n",