staging: lustre: mdt: add indexing option to default dir stripe

Add indexing option to default dirstripe EA. If MDT find
out the client send the create req to the wrong MDT because
of default stripeEA, it will return -EREMOTE, then client
will retrieve default stripeEA through xattr cache, and
re-create the object.

Also merged patch for LU-6341 to resolve the following problem.
Use ll_dir_getstripe to get default stripeEA in ll_new_node(),
Because ll_getxattr_common requires admin rights for retrieving
default LMVEA (because of trusted- prefix), which might cause
mkdir (from normal user) failure.

If parent does not have default stripeEA, then child should always
be in the same MDT for mkdir. Otherwise MDT should return -EREMOTE,
then client will refresh the default stripe index, and recreate
the object.

Signed-off-by: wang di <di.wang@intel.com>
Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-5523
Reviewed-on: http://review.whamcloud.com/13360
Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-6341
Reviewed-on: http://review.whamcloud.com/13990
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: Lai Siyao <lai.siyao@intel.com>
Reviewed-by: John L. Hammond <john.hammond@intel.com>
Reviewed-by: James Simmons <uja.ornl@yahoo.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>
Signed-off-by: James Simmons <jsimmons@infradead.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/lustre/lustre/include/obd.h

@@ -773,6 +773,9 @@ struct md_op_data {
 	/* File object data version for HSM release, on client */
 	__u64			op_data_version;
 	struct lustre_handle	op_lease_handle;
+
+	/* default stripe offset */
+	__u32			op_default_stripe_offset;
 };
 
 struct md_callback {

drivers/staging/lustre/lustre/llite/llite_internal.h

@@ -191,6 +191,13 @@ struct ll_inode_info {
 			unsigned int			lli_sa_generation;
 			/* directory stripe information */
 			struct lmv_stripe_md	       *lli_lsm_md;
+			/* default directory stripe offset.  This is extracted
+			 * from the "dmv" xattr in order to decide which MDT to
+			 * create a subdirectory on.  The MDS itself fetches
+			 * "dmv" and gets the rest of the default layout itself
+			 * (count, hash, etc).
+			 */
+			__u32				lli_def_stripe_offset;
 		};
 
 		/* for non-directory */

drivers/staging/lustre/lustre/llite/llite_lib.c

@@ -802,6 +802,7 @@ void ll_lli_init(struct ll_inode_info *lli)
 		spin_lock_init(&lli->lli_sa_lock);
 		lli->lli_opendir_pid = 0;
 		lli->lli_sa_enabled = 0;
+		lli->lli_def_stripe_offset = -1;
 	} else {
 		mutex_init(&lli->lli_size_mutex);
 		lli->lli_symlink_name = NULL;
@@ -2342,8 +2343,12 @@ struct md_op_data *ll_prep_md_op_data(struct md_op_data *op_data,
 
 	ll_i2gids(op_data->op_suppgids, i1, i2);
 	op_data->op_fid1 = *ll_inode2fid(i1);
-	if (S_ISDIR(i1->i_mode))
+	op_data->op_default_stripe_offset = -1;
+	if (S_ISDIR(i1->i_mode)) {
 		op_data->op_mea1 = ll_i2info(i1)->lli_lsm_md;
+		op_data->op_default_stripe_offset =
+			ll_i2info(i1)->lli_def_stripe_offset;
+	}
 
 	if (i2) {
 		op_data->op_fid2 = *ll_inode2fid(i2);

drivers/staging/lustre/lustre/llite/namei.c

@@ -204,6 +204,8 @@ int ll_md_blocking_ast(struct ldlm_lock *lock, struct ldlm_lock_desc *desc,
 		}
 
 		if (bits & MDS_INODELOCK_XATTR) {
+			if (S_ISDIR(inode->i_mode))
+				ll_i2info(inode)->lli_def_stripe_offset = -1;
 			ll_xattr_cache_destroy(inode);
 			bits &= ~MDS_INODELOCK_XATTR;
 		}
@@ -833,7 +835,7 @@ static int ll_new_node(struct inode *dir, struct dentry *dentry,
 
 	if (unlikely(tgt))
 		tgt_len = strlen(tgt) + 1;
-
+again:
 	op_data = ll_prep_md_op_data(NULL, dir, NULL,
 				     dentry->d_name.name,
 				     dentry->d_name.len,
@@ -848,9 +850,45 @@ static int ll_new_node(struct inode *dir, struct dentry *dentry,
 			from_kgid(&init_user_ns, current_fsgid()),
 			cfs_curproc_cap_pack(), rdev, &request);
 	ll_finish_md_op_data(op_data);
-	if (err)
+	if (err < 0 && err != -EREMOTE)
 		goto err_exit;
 
+	/*
+	 * If the client doesn't know where to create a subdirectory (or
+	 * in case of a race that sends the RPC to the wrong MDS), the
+	 * MDS will return -EREMOTE and the client will fetch the layout
+	 * of the directory, then create the directory on the right MDT.
+	 */
+	if (unlikely(err == -EREMOTE)) {
+		struct ll_inode_info *lli = ll_i2info(dir);
+		struct lmv_user_md *lum;
+		int lumsize, err2;
+
+		ptlrpc_req_finished(request);
+		request = NULL;
+
+		err2 = ll_dir_getstripe(dir, (void **)&lum, &lumsize, &request,
+					OBD_MD_DEFAULT_MEA);
+		if (!err2) {
+			/* Update stripe_offset and retry */
+			lli->lli_def_stripe_offset = lum->lum_stripe_offset;
+		} else if (err2 == -ENODATA &&
+			   lli->lli_def_stripe_offset != -1) {
+			/*
+			 * If there are no default stripe EA on the MDT, but the
+			 * client has default stripe, then it probably means
+			 * default stripe EA has just been deleted.
+			 */
+			lli->lli_def_stripe_offset = -1;
+		} else {
+			goto err_exit;
+		}
+
+		ptlrpc_req_finished(request);
+		request = NULL;
+		goto again;
+	}
+
 	ll_update_times(request, dir);
 
 	err = ll_prep_inode(&inode, request, dir->i_sb, NULL);
@@ -859,7 +897,8 @@ static int ll_new_node(struct inode *dir, struct dentry *dentry,
 
 	d_instantiate(dentry, inode);
 err_exit:
-	ptlrpc_req_finished(request);
+	if (request)
+		ptlrpc_req_finished(request);
 
 	return err;
 }

drivers/staging/lustre/lustre/lmv/lmv_obd.c

@@ -1162,6 +1162,11 @@ static int lmv_placement_policy(struct obd_device *obd,
 		return 0;
 	}
 
+	if (op_data->op_default_stripe_offset != -1) {
+		*mds = op_data->op_default_stripe_offset;
+		return 0;
+	}
+
 	/**
 	 * If stripe_offset is provided during setdirstripe
 	 * (setdirstripe -i xx), xx MDS will be chosen.