Merge tag 'ceph-for-4.12-rc1' of git://github.com/ceph/ceph-client

Pull ceph updates from Ilya Dryomov:
 "The two main items are support for disabling automatic rbd exclusive
  lock transfers from myself and the long awaited -ENOSPC handling
  series from Jeff.

  The former will allow rbd users to take advantage of exclusive lock's
  built-in blacklist/break-lock functionality while staying in control
  of who owns the lock. With the latter in place, we will abort
  filesystem writes on -ENOSPC instead of having them block
  indefinitely.

  Beyond that we've got the usual pile of filesystem fixes from Zheng,
  some refcount_t conversion patches from Elena and a patch for an
  ancient open() flags handling bug from Alexander"

* tag 'ceph-for-4.12-rc1' of git://github.com/ceph/ceph-client: (31 commits)
  ceph: fix memory leak in __ceph_setxattr()
  ceph: fix file open flags on ppc64
  ceph: choose readdir frag based on previous readdir reply
  rbd: exclusive map option
  rbd: return ResponseMessage result from rbd_handle_request_lock()
  rbd: kill rbd_is_lock_supported()
  rbd: support updating the lock cookie without releasing the lock
  rbd: store lock cookie
  rbd: ignore unlock errors
  rbd: fix error handling around rbd_init_disk()
  rbd: move rbd_unregister_watch() call into rbd_dev_image_release()
  rbd: move rbd_dev_destroy() call out of rbd_dev_image_release()
  ceph: when seeing write errors on an inode, switch to sync writes
  Revert "ceph: SetPageError() for writeback pages if writepages fails"
  ceph: handle epoch barriers in cap messages
  libceph: add an epoch_barrier field to struct ceph_osd_client
  libceph: abort already submitted but abortable requests when map or pool goes full
  libceph: allow requests to return immediately on full conditions if caller wishes
  libceph: remove req->r_replay_version
  ceph: make seeky readdir more efficient
  ...

13 files changed, 255 insertions, 86 deletions

diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c
index 9ecb2fd348cb..1e71e6ca5ddf 100644
--- a/fs/ceph/addr.c
+++ b/fs/ceph/addr.c
@@ -670,8 +670,12 @@ static void writepages_finish(struct ceph_osd_request *req)
 	bool remove_page;
 
 	dout("writepages_finish %p rc %d\n", inode, rc);
-	if (rc < 0)
+	if (rc < 0) {
 		mapping_set_error(mapping, rc);
+		ceph_set_error_write(ci);
+	} else {
+		ceph_clear_error_write(ci);
+	}
 
 	/*
 	 * We lost the cache cap, need to truncate the page before
@@ -703,9 +707,6 @@ static void writepages_finish(struct ceph_osd_request *req)
 				clear_bdi_congested(inode_to_bdi(inode),
 						    BLK_RW_ASYNC);
 
-			if (rc < 0)
-				SetPageError(page);
-
 			ceph_put_snap_context(page_snap_context(page));
 			page->private = 0;
 			ClearPagePrivate(page);
@@ -1892,6 +1893,7 @@ static int __ceph_pool_perm_get(struct ceph_inode_info *ci,
 	err = ceph_osdc_start_request(&fsc->client->osdc, rd_req, false);
 
 	wr_req->r_mtime = ci->vfs_inode.i_mtime;
+	wr_req->r_abort_on_full = true;
 	err2 = ceph_osdc_start_request(&fsc->client->osdc, wr_req, false);
 
 	if (!err)
diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c
index 68c78be19d5b..a3ebb632294e 100644
--- a/fs/ceph/caps.c
+++ b/fs/ceph/caps.c
@@ -1015,6 +1015,7 @@ static int send_cap_msg(struct cap_msg_args *arg)
 	void *p;
 	size_t extra_len;
 	struct timespec zerotime = {0};
+	struct ceph_osd_client *osdc = &arg->session->s_mdsc->fsc->client->osdc;
 
 	dout("send_cap_msg %s %llx %llx caps %s wanted %s dirty %s"
 	     " seq %u/%u tid %llu/%llu mseq %u follows %lld size %llu/%llu"
@@ -1076,8 +1077,12 @@ static int send_cap_msg(struct cap_msg_args *arg)
 	ceph_encode_64(&p, arg->inline_data ? 0 : CEPH_INLINE_NONE);
 	/* inline data size */
 	ceph_encode_32(&p, 0);
-	/* osd_epoch_barrier (version 5) */
-	ceph_encode_32(&p, 0);
+	/*
+	 * osd_epoch_barrier (version 5)
+	 * The epoch_barrier is protected osdc->lock, so READ_ONCE here in
+	 * case it was recently changed
+	 */
+	ceph_encode_32(&p, READ_ONCE(osdc->epoch_barrier));
 	/* oldest_flush_tid (version 6) */
 	ceph_encode_64(&p, arg->oldest_flush_tid);
 
@@ -1389,7 +1394,7 @@ static void __ceph_flush_snaps(struct ceph_inode_info *ci,
 		first_tid = cf->tid + 1;
 
 		capsnap = container_of(cf, struct ceph_cap_snap, cap_flush);
-		atomic_inc(&capsnap->nref);
+		refcount_inc(&capsnap->nref);
 		spin_unlock(&ci->i_ceph_lock);
 
 		dout("__flush_snaps %p capsnap %p tid %llu %s\n",
@@ -2202,7 +2207,7 @@ static void __kick_flushing_caps(struct ceph_mds_client *mdsc,
 			     inode, capsnap, cf->tid,
 			     ceph_cap_string(capsnap->dirty));
 
-			atomic_inc(&capsnap->nref);
+			refcount_inc(&capsnap->nref);
 			spin_unlock(&ci->i_ceph_lock);
 
 			ret = __send_flush_snap(inode, session, capsnap, cap->mseq,
@@ -3633,13 +3638,19 @@ void ceph_handle_caps(struct ceph_mds_session *session,
 		p += inline_len;
 	}
 
+	if (le16_to_cpu(msg->hdr.version) >= 5) {
+		struct ceph_osd_client	*osdc = &mdsc->fsc->client->osdc;
+		u32			epoch_barrier;
+
+		ceph_decode_32_safe(&p, end, epoch_barrier, bad);
+		ceph_osdc_update_epoch_barrier(osdc, epoch_barrier);
+	}
+
 	if (le16_to_cpu(msg->hdr.version) >= 8) {
 		u64 flush_tid;
 		u32 caller_uid, caller_gid;
-		u32 osd_epoch_barrier;
 		u32 pool_ns_len;
-		/* version >= 5 */
-		ceph_decode_32_safe(&p, end, osd_epoch_barrier, bad);
+
 		/* version >= 6 */
 		ceph_decode_64_safe(&p, end, flush_tid, bad);
 		/* version >= 7 */
diff --git a/fs/ceph/debugfs.c b/fs/ceph/debugfs.c
index 3ef11bc8d728..4e2d112c982f 100644
--- a/fs/ceph/debugfs.c
+++ b/fs/ceph/debugfs.c
@@ -22,20 +22,19 @@ static int mdsmap_show(struct seq_file *s, void *p)
 {
 	int i;
 	struct ceph_fs_client *fsc = s->private;
+	struct ceph_mdsmap *mdsmap;
 
 	if (fsc->mdsc == NULL || fsc->mdsc->mdsmap == NULL)
 		return 0;
-	seq_printf(s, "epoch %d\n", fsc->mdsc->mdsmap->m_epoch);
-	seq_printf(s, "root %d\n", fsc->mdsc->mdsmap->m_root);
-	seq_printf(s, "session_timeout %d\n",
-		       fsc->mdsc->mdsmap->m_session_timeout);
-	seq_printf(s, "session_autoclose %d\n",
-		       fsc->mdsc->mdsmap->m_session_autoclose);
-	for (i = 0; i < fsc->mdsc->mdsmap->m_max_mds; i++) {
-		struct ceph_entity_addr *addr =
-			&fsc->mdsc->mdsmap->m_info[i].addr;
-		int state = fsc->mdsc->mdsmap->m_info[i].state;
-
+	mdsmap = fsc->mdsc->mdsmap;
+	seq_printf(s, "epoch %d\n", mdsmap->m_epoch);
+	seq_printf(s, "root %d\n", mdsmap->m_root);
+	seq_printf(s, "max_mds %d\n", mdsmap->m_max_mds);
+	seq_printf(s, "session_timeout %d\n", mdsmap->m_session_timeout);
+	seq_printf(s, "session_autoclose %d\n", mdsmap->m_session_autoclose);
+	for (i = 0; i < mdsmap->m_num_mds; i++) {
+		struct ceph_entity_addr *addr = &mdsmap->m_info[i].addr;
+		int state = mdsmap->m_info[i].state;
 		seq_printf(s, "\tmds%d\t%s\t(%s)\n", i,
 			       ceph_pr_addr(&addr->in_addr),
 			       ceph_mds_state_name(state));
diff --git a/fs/ceph/dir.c b/fs/ceph/dir.c
index 3e9ad501addf..e071d23f6148 100644
--- a/fs/ceph/dir.c
+++ b/fs/ceph/dir.c
@@ -294,7 +294,7 @@ static int ceph_readdir(struct file *file, struct dir_context *ctx)
 	struct ceph_mds_client *mdsc = fsc->mdsc;
 	int i;
 	int err;
-	u32 ftype;
+	unsigned frag = -1;
 	struct ceph_mds_reply_info_parsed *rinfo;
 
 	dout("readdir %p file %p pos %llx\n", inode, file, ctx->pos);
@@ -341,7 +341,6 @@ more:
 	/* do we have the correct frag content buffered? */
 	if (need_send_readdir(fi, ctx->pos)) {
 		struct ceph_mds_request *req;
-		unsigned frag;
 		int op = ceph_snap(inode) == CEPH_SNAPDIR ?
 			CEPH_MDS_OP_LSSNAP : CEPH_MDS_OP_READDIR;
 
@@ -352,8 +351,11 @@ more:
 		}
 
 		if (is_hash_order(ctx->pos)) {
-			frag = ceph_choose_frag(ci, fpos_hash(ctx->pos),
-						NULL, NULL);
+			/* fragtree isn't always accurate. choose frag
+			 * based on previous reply when possible. */
+			if (frag == (unsigned)-1)
+				frag = ceph_choose_frag(ci, fpos_hash(ctx->pos),
+							NULL, NULL);
 		} else {
 			frag = fpos_frag(ctx->pos);
 		}
@@ -378,7 +380,11 @@ more:
 				ceph_mdsc_put_request(req);
 				return -ENOMEM;
 			}
+		} else if (is_hash_order(ctx->pos)) {
+			req->r_args.readdir.offset_hash =
+				cpu_to_le32(fpos_hash(ctx->pos));
 		}
+
 		req->r_dir_release_cnt = fi->dir_release_count;
 		req->r_dir_ordered_cnt = fi->dir_ordered_count;
 		req->r_readdir_cache_idx = fi->readdir_cache_idx;
@@ -476,6 +482,7 @@ more:
 		struct ceph_mds_reply_dir_entry *rde = rinfo->dir_entries + i;
 		struct ceph_vino vino;
 		ino_t ino;
+		u32 ftype;
 
 		BUG_ON(rde->offset < ctx->pos);
 
@@ -498,15 +505,17 @@ more:
 		ctx->pos++;
 	}
 
+	ceph_mdsc_put_request(fi->last_readdir);
+	fi->last_readdir = NULL;
+
 	if (fi->next_offset > 2) {
-		ceph_mdsc_put_request(fi->last_readdir);
-		fi->last_readdir = NULL;
+		frag = fi->frag;
 		goto more;
 	}
 
 	/* more frags? */
 	if (!ceph_frag_is_rightmost(fi->frag)) {
-		unsigned frag = ceph_frag_next(fi->frag);
+		frag = ceph_frag_next(fi->frag);
 		if (is_hash_order(ctx->pos)) {
 			loff_t new_pos = ceph_make_fpos(ceph_frag_value(frag),
 							fi->next_offset, true);
diff --git a/fs/ceph/file.c b/fs/ceph/file.c
index 18c045e2ead6..3fdde0b283c9 100644
--- a/fs/ceph/file.c
+++ b/fs/ceph/file.c
@@ -13,6 +13,38 @@
 #include "mds_client.h"
 #include "cache.h"
 
+static __le32 ceph_flags_sys2wire(u32 flags)
+{
+	u32 wire_flags = 0;
+
+	switch (flags & O_ACCMODE) {
+	case O_RDONLY:
+		wire_flags |= CEPH_O_RDONLY;
+		break;
+	case O_WRONLY:
+		wire_flags |= CEPH_O_WRONLY;
+		break;
+	case O_RDWR:
+		wire_flags |= CEPH_O_RDWR;
+		break;
+	}
+
+#define ceph_sys2wire(a) if (flags & a) { wire_flags |= CEPH_##a; flags &= ~a; }
+
+	ceph_sys2wire(O_CREAT);
+	ceph_sys2wire(O_EXCL);
+	ceph_sys2wire(O_TRUNC);
+	ceph_sys2wire(O_DIRECTORY);
+	ceph_sys2wire(O_NOFOLLOW);
+
+#undef ceph_sys2wire
+
+	if (flags)
+		dout("unused open flags: %x", flags);
+
+	return cpu_to_le32(wire_flags);
+}
+
 /*
  * Ceph file operations
  *
@@ -120,7 +152,7 @@ prepare_open_request(struct super_block *sb, int flags, int create_mode)
 	if (IS_ERR(req))
 		goto out;
 	req->r_fmode = ceph_flags_to_mode(flags);
-	req->r_args.open.flags = cpu_to_le32(flags);
+	req->r_args.open.flags = ceph_flags_sys2wire(flags);
 	req->r_args.open.mode = cpu_to_le32(create_mode);
 out:
 	return req;
@@ -189,7 +221,7 @@ int ceph_renew_caps(struct inode *inode)
 	spin_lock(&ci->i_ceph_lock);
 	wanted = __ceph_caps_file_wanted(ci);
 	if (__ceph_is_any_real_caps(ci) &&
-	    (!(wanted & CEPH_CAP_ANY_WR) == 0 || ci->i_auth_cap)) {
+	    (!(wanted & CEPH_CAP_ANY_WR) || ci->i_auth_cap)) {
 		int issued = __ceph_caps_issued(ci, NULL);
 		spin_unlock(&ci->i_ceph_lock);
 		dout("renew caps %p want %s issued %s updating mds_wanted\n",
@@ -778,6 +810,7 @@ static void ceph_aio_retry_work(struct work_struct *work)
 	req->r_callback = ceph_aio_complete_req;
 	req->r_inode = inode;
 	req->r_priv = aio_req;
+	req->r_abort_on_full = true;
 
 	ret = ceph_osdc_start_request(req->r_osdc, req, false);
 out:
@@ -1085,19 +1118,22 @@ ceph_sync_write(struct kiocb *iocb, struct iov_iter *from, loff_t pos,
 
 out:
 		ceph_osdc_put_request(req);
-		if (ret == 0) {
-			pos += len;
-			written += len;
-
-			if (pos > i_size_read(inode)) {
-				check_caps = ceph_inode_set_size(inode, pos);
-				if (check_caps)
-					ceph_check_caps(ceph_inode(inode),
-							CHECK_CAPS_AUTHONLY,
-							NULL);
-			}
-		} else
+		if (ret != 0) {
+			ceph_set_error_write(ci);
 			break;
+		}
+
+		ceph_clear_error_write(ci);
+		pos += len;
+		written += len;
+		if (pos > i_size_read(inode)) {
+			check_caps = ceph_inode_set_size(inode, pos);
+			if (check_caps)
+				ceph_check_caps(ceph_inode(inode),
+						CHECK_CAPS_AUTHONLY,
+						NULL);
+		}
+
 	}
 
 	if (ret != -EOLDSNAPC && written > 0) {
@@ -1303,6 +1339,7 @@ static ssize_t ceph_write_iter(struct kiocb *iocb, struct iov_iter *from)
 	}
 
 retry_snap:
+	/* FIXME: not complete since it doesn't account for being at quota */
 	if (ceph_osdmap_flag(osdc, CEPH_OSDMAP_FULL)) {
 		err = -ENOSPC;
 		goto out;
@@ -1324,7 +1361,8 @@ retry_snap:
 	     inode, ceph_vinop(inode), pos, count, ceph_cap_string(got));
 
 	if ((got & (CEPH_CAP_FILE_BUFFER|CEPH_CAP_FILE_LAZYIO)) == 0 ||
-	    (iocb->ki_flags & IOCB_DIRECT) || (fi->flags & CEPH_F_SYNC)) {
+	    (iocb->ki_flags & IOCB_DIRECT) || (fi->flags & CEPH_F_SYNC) ||
+	    (ci->i_ceph_flags & CEPH_I_ERROR_WRITE)) {
 		struct ceph_snap_context *snapc;
 		struct iov_iter data;
 		inode_unlock(inode);
diff --git a/fs/ceph/inode.c b/fs/ceph/inode.c
index d3119fe3ab45..dcce79b84406 100644
--- a/fs/ceph/inode.c
+++ b/fs/ceph/inode.c
@@ -1482,10 +1482,17 @@ int ceph_readdir_prepopulate(struct ceph_mds_request *req,
 	if (test_bit(CEPH_MDS_R_ABORTED, &req->r_req_flags))
 		return readdir_prepopulate_inodes_only(req, session);
 
-	if (rinfo->hash_order && req->r_path2) {
-		last_hash = ceph_str_hash(ci->i_dir_layout.dl_dir_hash,
-					  req->r_path2, strlen(req->r_path2));
-		last_hash = ceph_frag_value(last_hash);
+	if (rinfo->hash_order) {
+		if (req->r_path2) {
+			last_hash = ceph_str_hash(ci->i_dir_layout.dl_dir_hash,
+						  req->r_path2,
+						  strlen(req->r_path2));
+			last_hash = ceph_frag_value(last_hash);
+		} else if (rinfo->offset_hash) {
+			/* mds understands offset_hash */
+			WARN_ON_ONCE(req->r_readdir_offset != 2);
+			last_hash = le32_to_cpu(rhead->args.readdir.offset_hash);
+		}
 	}
 
 	if (rinfo->dir_dir &&
@@ -1510,7 +1517,7 @@ int ceph_readdir_prepopulate(struct ceph_mds_request *req,
 	}
 
 	if (ceph_frag_is_leftmost(frag) && req->r_readdir_offset == 2 &&
-	    !(rinfo->hash_order && req->r_path2)) {
+	    !(rinfo->hash_order && last_hash)) {
 		/* note dir version at start of readdir so we can tell
 		 * if any dentries get dropped */
 		req->r_dir_release_cnt = atomic64_read(&ci->i_release_count);
diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
index 1d3fa90d40b9..f38e56fa9712 100644
--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -189,6 +189,7 @@ static int parse_reply_info_dir(void **p, void *end,
 		info->dir_end = !!(flags & CEPH_READDIR_FRAG_END);
 		info->dir_complete = !!(flags & CEPH_READDIR_FRAG_COMPLETE);
 		info->hash_order = !!(flags & CEPH_READDIR_HASH_ORDER);
+		info->offset_hash = !!(flags & CEPH_READDIR_OFFSET_HASH);
 	}
 	if (num == 0)
 		goto done;
@@ -378,9 +379,9 @@ const char *ceph_session_state_name(int s)
 
 static struct ceph_mds_session *get_session(struct ceph_mds_session *s)
 {
-	if (atomic_inc_not_zero(&s->s_ref)) {
+	if (refcount_inc_not_zero(&s->s_ref)) {
 		dout("mdsc get_session %p %d -> %d\n", s,
-		     atomic_read(&s->s_ref)-1, atomic_read(&s->s_ref));
+		     refcount_read(&s->s_ref)-1, refcount_read(&s->s_ref));
 		return s;
 	} else {
 		dout("mdsc get_session %p 0 -- FAIL", s);
@@ -391,8 +392,8 @@ static struct ceph_mds_session *get_session(struct ceph_mds_session *s)
 void ceph_put_mds_session(struct ceph_mds_session *s)
 {
 	dout("mdsc put_session %p %d -> %d\n", s,
-	     atomic_read(&s->s_ref), atomic_read(&s->s_ref)-1);
-	if (atomic_dec_and_test(&s->s_ref)) {
+	     refcount_read(&s->s_ref), refcount_read(&s->s_ref)-1);
+	if (refcount_dec_and_test(&s->s_ref)) {
 		if (s->s_auth.authorizer)
 			ceph_auth_destroy_authorizer(s->s_auth.authorizer);
 		kfree(s);
@@ -411,7 +412,7 @@ struct ceph_mds_session *__ceph_lookup_mds_session(struct ceph_mds_client *mdsc,
 		return NULL;
 	session = mdsc->sessions[mds];
 	dout("lookup_mds_session %p %d\n", session,
-	     atomic_read(&session->s_ref));
+	     refcount_read(&session->s_ref));
 	get_session(session);
 	return session;
 }
@@ -441,7 +442,7 @@ static struct ceph_mds_session *register_session(struct ceph_mds_client *mdsc,
 {
 	struct ceph_mds_session *s;
 
-	if (mds >= mdsc->mdsmap->m_max_mds)
+	if (mds >= mdsc->mdsmap->m_num_mds)
 		return ERR_PTR(-EINVAL);
 
 	s = kzalloc(sizeof(*s), GFP_NOFS);
@@ -466,7 +467,7 @@ static struct ceph_mds_session *register_session(struct ceph_mds_client *mdsc,
 	INIT_LIST_HEAD(&s->s_caps);
 	s->s_nr_caps = 0;
 	s->s_trim_caps = 0;
-	atomic_set(&s->s_ref, 1);
+	refcount_set(&s->s_ref, 1);
 	INIT_LIST_HEAD(&s->s_waiting);
 	INIT_LIST_HEAD(&s->s_unsafe);
 	s->s_num_cap_releases = 0;
@@ -494,7 +495,7 @@ static struct ceph_mds_session *register_session(struct ceph_mds_client *mdsc,
 	}
 	mdsc->sessions[mds] = s;
 	atomic_inc(&mdsc->num_sessions);
-	atomic_inc(&s->s_ref);  /* one ref to sessions[], one to caller */
+	refcount_inc(&s->s_ref);  /* one ref to sessions[], one to caller */
 
 	ceph_con_open(&s->s_con, CEPH_ENTITY_TYPE_MDS, mds,
 		      ceph_mdsmap_get_addr(mdsc->mdsmap, mds));
@@ -1004,7 +1005,7 @@ static void __open_export_target_sessions(struct ceph_mds_client *mdsc,
 	struct ceph_mds_session *ts;
 	int i, mds = session->s_mds;
 
-	if (mds >= mdsc->mdsmap->m_max_mds)
+	if (mds >= mdsc->mdsmap->m_num_mds)
 		return;
 
 	mi = &mdsc->mdsmap->m_info[mds];
@@ -1551,9 +1552,15 @@ void ceph_send_cap_releases(struct ceph_mds_client *mdsc,
 	struct ceph_msg *msg = NULL;
 	struct ceph_mds_cap_release *head;
 	struct ceph_mds_cap_item *item;
+	struct ceph_osd_client *osdc = &mdsc->fsc->client->osdc;
 	struct ceph_cap *cap;
 	LIST_HEAD(tmp_list);
 	int num_cap_releases;
+	__le32	barrier, *cap_barrier;
+
+	down_read(&osdc->lock);
+	barrier = cpu_to_le32(osdc->epoch_barrier);
+	up_read(&osdc->lock);
 
 	spin_lock(&session->s_cap_lock);
 again:
@@ -1571,7 +1578,11 @@ again:
 			head = msg->front.iov_base;
 			head->num = cpu_to_le32(0);
 			msg->front.iov_len = sizeof(*head);
+
+			msg->hdr.version = cpu_to_le16(2);
+			msg->hdr.compat_version = cpu_to_le16(1);
 		}
+
 		cap = list_first_entry(&tmp_list, struct ceph_cap,
 					session_caps);
 		list_del(&cap->session_caps);
@@ -1589,6 +1600,11 @@ again:
 		ceph_put_cap(mdsc, cap);
 
 		if (le32_to_cpu(head->num) == CEPH_CAPS_PER_RELEASE) {
+			// Append cap_barrier field
+			cap_barrier = msg->front.iov_base + msg->front.iov_len;
+			*cap_barrier = barrier;
+			msg->front.iov_len += sizeof(*cap_barrier);
+
 			msg->hdr.front_len = cpu_to_le32(msg->front.iov_len);
 			dout("send_cap_releases mds%d %p\n", session->s_mds, msg);
 			ceph_con_send(&session->s_con, msg);
@@ -1604,6 +1620,11 @@ again:
 	spin_unlock(&session->s_cap_lock);
 
 	if (msg) {
+		// Append cap_barrier field
+		cap_barrier = msg->front.iov_base + msg->front.iov_len;
+		*cap_barrier = barrier;
+		msg->front.iov_len += sizeof(*cap_barrier);
+
 		msg->hdr.front_len = cpu_to_le32(msg->front.iov_len);
 		dout("send_cap_releases mds%d %p\n", session->s_mds, msg);
 		ceph_con_send(&session->s_con, msg);
@@ -1993,7 +2014,7 @@ static struct ceph_msg *create_request_message(struct ceph_mds_client *mdsc,
 
 	if (req->r_pagelist) {
 		struct ceph_pagelist *pagelist = req->r_pagelist;
-		atomic_inc(&pagelist->refcnt);
+		refcount_inc(&pagelist->refcnt);
 		ceph_msg_data_add_pagelist(msg, pagelist);
 		msg->hdr.data_len = cpu_to_le32(pagelist->length);
 	} else {
@@ -2640,8 +2661,10 @@ static void handle_session(struct ceph_mds_session *session,
 	seq = le64_to_cpu(h->seq);
 
 	mutex_lock(&mdsc->mutex);
-	if (op == CEPH_SESSION_CLOSE)
+	if (op == CEPH_SESSION_CLOSE) {
+		get_session(session);
 		__unregister_session(mdsc, session);
+	}
 	/* FIXME: this ttl calculation is generous */
 	session->s_ttl = jiffies + HZ*mdsc->mdsmap->m_session_autoclose;
 	mutex_unlock(&mdsc->mutex);
@@ -2730,6 +2753,8 @@ static void handle_session(struct ceph_mds_session *session,
 			kick_requests(mdsc, mds);
 		mutex_unlock(&mdsc->mutex);
 	}
+	if (op == CEPH_SESSION_CLOSE)
+		ceph_put_mds_session(session);
 	return;
 
 bad:
@@ -3109,7 +3134,7 @@ static void check_new_map(struct ceph_mds_client *mdsc,
 	dout("check_new_map new %u old %u\n",
 	     newmap->m_epoch, oldmap->m_epoch);
 
-	for (i = 0; i < oldmap->m_max_mds && i < mdsc->max_sessions; i++) {
+	for (i = 0; i < oldmap->m_num_mds && i < mdsc->max_sessions; i++) {
 		if (mdsc->sessions[i] == NULL)
 			continue;
 		s = mdsc->sessions[i];
@@ -3123,15 +3148,33 @@ static void check_new_map(struct ceph_mds_client *mdsc,
 		     ceph_mdsmap_is_laggy(newmap, i) ? " (laggy)" : "",
 		     ceph_session_state_name(s->s_state));
 
-		if (i >= newmap->m_max_mds ||
+		if (i >= newmap->m_num_mds ||
 		    memcmp(ceph_mdsmap_get_addr(oldmap, i),
 			   ceph_mdsmap_get_addr(newmap, i),
 			   sizeof(struct ceph_entity_addr))) {
 			if (s->s_state == CEPH_MDS_SESSION_OPENING) {
 				/* the session never opened, just close it
 				 * out now */
+				get_session(s);
+				__unregister_session(mdsc, s);
 				__wake_requests(mdsc, &s->s_waiting);
+				ceph_put_mds_session(s);
+			} else if (i >= newmap->m_num_mds) {
+				/* force close session for stopped mds */
+				get_session(s);
 				__unregister_session(mdsc, s);
+				__wake_requests(mdsc, &s->s_waiting);
+				kick_requests(mdsc, i);
+				mutex_unlock(&mdsc->mutex);
+
+				mutex_lock(&s->s_mutex);
+				cleanup_session_requests(mdsc, s);
+				remove_session_caps(s);
+				mutex_unlock(&s->s_mutex);
+
+				ceph_put_mds_session(s);
+
+				mutex_lock(&mdsc->mutex);
 			} else {
 				/* just close it */
 				mutex_unlock(&mdsc->mutex);
@@ -3169,7 +3212,7 @@ static void check_new_map(struct ceph_mds_client *mdsc,
 		}
 	}
 
-	for (i = 0; i < newmap->m_max_mds && i < mdsc->max_sessions; i++) {
+	for (i = 0; i < newmap->m_num_mds && i < mdsc->max_sessions; i++) {
 		s = mdsc->sessions[i];
 		if (!s)
 			continue;
@@ -3883,7 +3926,7 @@ static struct ceph_connection *con_get(struct ceph_connection *con)
 	struct ceph_mds_session *s = con->private;
 
 	if (get_session(s)) {
-		dout("mdsc con_get %p ok (%d)\n", s, atomic_read(&s->s_ref));
+		dout("mdsc con_get %p ok (%d)\n", s, refcount_read(&s->s_ref));
 		return con;
 	}
 	dout("mdsc con_get %p FAIL\n", s);
@@ -3894,7 +3937,7 @@ static void con_put(struct ceph_connection *con)
 {
 	struct ceph_mds_session *s = con->private;
 
-	dout("mdsc con_put %p (%d)\n", s, atomic_read(&s->s_ref) - 1);
+	dout("mdsc con_put %p (%d)\n", s, refcount_read(&s->s_ref) - 1);
 	ceph_put_mds_session(s);
 }
 
diff --git a/fs/ceph/mds_client.h b/fs/ceph/mds_client.h
index ac0475a2daa7..db57ae98ed34 100644
--- a/fs/ceph/mds_client.h
+++ b/fs/ceph/mds_client.h
@@ -7,6 +7,7 @@
 #include <linux/mutex.h>
 #include <linux/rbtree.h>
 #include <linux/spinlock.h>
+#include <linux/refcount.h>
 
 #include <linux/ceph/types.h>
 #include <linux/ceph/messenger.h>
@@ -82,9 +83,10 @@ struct ceph_mds_reply_info_parsed {
 			struct ceph_mds_reply_dirfrag *dir_dir;
 			size_t			      dir_buf_size;
 			int                           dir_nr;
-			bool			      dir_complete;
 			bool			      dir_end;
+			bool			      dir_complete;
 			bool			      hash_order;
+			bool			      offset_hash;
 			struct ceph_mds_reply_dir_entry  *dir_entries;
 		};
 
@@ -104,10 +106,13 @@ struct ceph_mds_reply_info_parsed {
 
 /*
  * cap releases are batched and sent to the MDS en masse.
+ *
+ * Account for per-message overhead of mds_cap_release header
+ * and __le32 for osd epoch barrier trailing field.
  */
-#define CEPH_CAPS_PER_RELEASE ((PAGE_SIZE -			\
+#define CEPH_CAPS_PER_RELEASE ((PAGE_SIZE - sizeof(u32) -		\
 				sizeof(struct ceph_mds_cap_release)) /	\
-			       sizeof(struct ceph_mds_cap_item))
+			        sizeof(struct ceph_mds_cap_item))
 
 
 /*
@@ -156,7 +161,7 @@ struct ceph_mds_session {
 	unsigned long     s_renew_requested; /* last time we sent a renew req */
 	u64               s_renew_seq;
 
-	atomic_t          s_ref;
+	refcount_t          s_ref;
 	struct list_head  s_waiting;  /* waiting requests */
 	struct list_head  s_unsafe;   /* unsafe requests */
 };
@@ -373,7 +378,7 @@ __ceph_lookup_mds_session(struct ceph_mds_client *, int mds);
 static inline struct ceph_mds_session *
 ceph_get_mds_session(struct ceph_mds_session *s)
 {
-	atomic_inc(&s->s_ref);
+	refcount_inc(&s->s_ref);
 	return s;
 }
 
diff --git a/fs/ceph/mdsmap.c b/fs/ceph/mdsmap.c
index 5454e2327a5f..1a748cf88535 100644
--- a/fs/ceph/mdsmap.c
+++ b/fs/ceph/mdsmap.c
@@ -22,11 +22,11 @@ int ceph_mdsmap_get_random_mds(struct ceph_mdsmap *m)
 	int i;
 
 	/* special case for one mds */
-	if (1 == m->m_max_mds && m->m_info[0].state > 0)
+	if (1 == m->m_num_mds && m->m_info[0].state > 0)
 		return 0;
 
 	/* count */
-	for (i = 0; i < m->m_max_mds; i++)
+	for (i = 0; i < m->m_num_mds; i++)
 		if (m->m_info[i].state > 0)
 			n++;
 	if (n == 0)
@@ -135,8 +135,9 @@ struct ceph_mdsmap *ceph_mdsmap_decode(void **p, void *end)
 	m->m_session_autoclose = ceph_decode_32(p);
 	m->m_max_file_size = ceph_decode_64(p);
 	m->m_max_mds = ceph_decode_32(p);
+	m->m_num_mds = m->m_max_mds;
 
-	m->m_info = kcalloc(m->m_max_mds, sizeof(*m->m_info), GFP_NOFS);
+	m->m_info = kcalloc(m->m_num_mds, sizeof(*m->m_info), GFP_NOFS);
 	if (m->m_info == NULL)
 		goto nomem;
 
@@ -207,9 +208,20 @@ struct ceph_mdsmap *ceph_mdsmap_decode(void **p, void *end)
 		     ceph_pr_addr(&addr.in_addr),
 		     ceph_mds_state_name(state));
 
-		if (mds < 0 || mds >= m->m_max_mds || state <= 0)
+		if (mds < 0 || state <= 0)
 			continue;
 
+		if (mds >= m->m_num_mds) {
+			int new_num = max(mds + 1, m->m_num_mds * 2);
+			void *new_m_info = krealloc(m->m_info,
+						new_num * sizeof(*m->m_info),
+						GFP_NOFS | __GFP_ZERO);
+			if (!new_m_info)
+				goto nomem;
+			m->m_info = new_m_info;
+			m->m_num_mds = new_num;
+		}
+
 		info = &m->m_info[mds];
 		info->global_id = global_id;
 		info->state = state;
@@ -229,6 +241,14 @@ struct ceph_mdsmap *ceph_mdsmap_decode(void **p, void *end)
 			info->export_targets = NULL;
 		}
 	}
+	if (m->m_num_mds > m->m_max_mds) {
+		/* find max up mds */
+		for (i = m->m_num_mds; i >= m->m_max_mds; i--) {
+			if (i == 0 || m->m_info[i-1].state > 0)
+				break;
+		}
+		m->m_num_mds = i;
+	}
 
 	/* pg_pools */
 	ceph_decode_32_safe(p, end, n, bad);
@@ -270,12 +290,22 @@ struct ceph_mdsmap *ceph_mdsmap_decode(void **p, void *end)
 
 		for (i = 0; i < n; i++) {
 			s32 mds = ceph_decode_32(p);
-			if (mds >= 0 && mds < m->m_max_mds) {
+			if (mds >= 0 && mds < m->m_num_mds) {
 				if (m->m_info[mds].laggy)
 					num_laggy++;
 			}
 		}
 		m->m_num_laggy = num_laggy;
+
+		if (n > m->m_num_mds) {
+			void *new_m_info = krealloc(m->m_info,
+						    n * sizeof(*m->m_info),
+						    GFP_NOFS | __GFP_ZERO);
+			if (!new_m_info)
+				goto nomem;
+			m->m_info = new_m_info;
+		}
+		m->m_num_mds = n;
 	}
 
 	/* inc */
@@ -341,7 +371,7 @@ void ceph_mdsmap_destroy(struct ceph_mdsmap *m)
 {
 	int i;
 
-	for (i = 0; i < m->m_max_mds; i++)
+	for (i = 0; i < m->m_num_mds; i++)
 		kfree(m->m_info[i].export_targets);
 	kfree(m->m_info);
 	kfree(m->m_data_pg_pools);
@@ -357,7 +387,7 @@ bool ceph_mdsmap_is_cluster_available(struct ceph_mdsmap *m)
 		return false;
 	if (m->m_num_laggy > 0)
 		return false;
-	for (i = 0; i < m->m_max_mds; i++) {
+	for (i = 0; i < m->m_num_mds; i++) {
 		if (m->m_info[i].state == CEPH_MDS_STATE_ACTIVE)
 			nr_active++;
 	}
diff --git a/fs/ceph/snap.c b/fs/ceph/snap.c
index 8f8b41c2ef0f..dab5d6732345 100644
--- a/fs/ceph/snap.c
+++ b/fs/ceph/snap.c
@@ -519,7 +519,7 @@ void ceph_queue_cap_snap(struct ceph_inode_info *ci)
 	     capsnap->need_flush ? "" : "no_flush");
 	ihold(inode);
 
-	atomic_set(&capsnap->nref, 1);
+	refcount_set(&capsnap->nref, 1);
 	INIT_LIST_HEAD(&capsnap->ci_item);
 
 	capsnap->follows = old_snapc->seq;
diff --git a/fs/ceph/super.c b/fs/ceph/super.c
index a8c81b2052ca..8d7918ce694a 100644
--- a/fs/ceph/super.c
+++ b/fs/ceph/super.c
@@ -544,10 +544,6 @@ static struct ceph_fs_client *create_fs_client(struct ceph_mount_options *fsopt,
 					struct ceph_options *opt)
 {
 	struct ceph_fs_client *fsc;
-	const u64 supported_features =
-		CEPH_FEATURE_FLOCK | CEPH_FEATURE_DIRLAYOUTHASH |
-		CEPH_FEATURE_MDSENC | CEPH_FEATURE_MDS_INLINE_DATA;
-	const u64 required_features = 0;
 	int page_count;
 	size_t size;
 	int err = -ENOMEM;
@@ -556,8 +552,7 @@ static struct ceph_fs_client *create_fs_client(struct ceph_mount_options *fsopt,
 	if (!fsc)
 		return ERR_PTR(-ENOMEM);
 
-	fsc->client = ceph_create_client(opt, fsc, supported_features,
-					 required_features);
+	fsc->client = ceph_create_client(opt, fsc);
 	if (IS_ERR(fsc->client)) {
 		err = PTR_ERR(fsc->client);
 		goto fail;
diff --git a/fs/ceph/super.h b/fs/ceph/super.h
index 176186b12457..a973acd8beaf 100644
--- a/fs/ceph/super.h
+++ b/fs/ceph/super.h
@@ -14,6 +14,7 @@
 #include <linux/writeback.h>
 #include <linux/slab.h>
 #include <linux/posix_acl.h>
+#include <linux/refcount.h>
 
 #include <linux/ceph/libceph.h>
 
@@ -160,7 +161,7 @@ struct ceph_cap_flush {
  * data before flushing the snapped state (tracked here) back to the MDS.
  */
 struct ceph_cap_snap {
-	atomic_t nref;
+	refcount_t nref;
 	struct list_head ci_item;
 
 	struct ceph_cap_flush cap_flush;
@@ -189,7 +190,7 @@ struct ceph_cap_snap {
 
 static inline void ceph_put_cap_snap(struct ceph_cap_snap *capsnap)
 {
-	if (atomic_dec_and_test(&capsnap->nref)) {
+	if (refcount_dec_and_test(&capsnap->nref)) {
 		if (capsnap->xattr_blob)
 			ceph_buffer_put(capsnap->xattr_blob);
 		kfree(capsnap);
@@ -471,6 +472,32 @@ static inline struct inode *ceph_find_inode(struct super_block *sb,
 #define CEPH_I_CAP_DROPPED	(1 << 8)  /* caps were forcibly dropped */
 #define CEPH_I_KICK_FLUSH	(1 << 9)  /* kick flushing caps */
 #define CEPH_I_FLUSH_SNAPS	(1 << 10) /* need flush snapss */
+#define CEPH_I_ERROR_WRITE	(1 << 11) /* have seen write errors */
+
+/*
+ * We set the ERROR_WRITE bit when we start seeing write errors on an inode
+ * and then clear it when they start succeeding. Note that we do a lockless
+ * check first, and only take the lock if it looks like it needs to be changed.
+ * The write submission code just takes this as a hint, so we're not too
+ * worried if a few slip through in either direction.
+ */
+static inline void ceph_set_error_write(struct ceph_inode_info *ci)
+{
+	if (!(READ_ONCE(ci->i_ceph_flags) & CEPH_I_ERROR_WRITE)) {
+		spin_lock(&ci->i_ceph_lock);
+		ci->i_ceph_flags |= CEPH_I_ERROR_WRITE;
+		spin_unlock(&ci->i_ceph_lock);
+	}
+}
+
+static inline void ceph_clear_error_write(struct ceph_inode_info *ci)
+{
+	if (READ_ONCE(ci->i_ceph_flags) & CEPH_I_ERROR_WRITE) {
+		spin_lock(&ci->i_ceph_lock);
+		ci->i_ceph_flags &= ~CEPH_I_ERROR_WRITE;
+		spin_unlock(&ci->i_ceph_lock);
+	}
+}
 
 static inline void __ceph_dir_set_complete(struct ceph_inode_info *ci,
 					   long long release_count,
diff --git a/fs/ceph/xattr.c b/fs/ceph/xattr.c
index febc28f9e2c2..75267cdd5dfd 100644
--- a/fs/ceph/xattr.c
+++ b/fs/ceph/xattr.c
@@ -392,6 +392,7 @@ static int __set_xattr(struct ceph_inode_info *ci,
 
 	if (update_xattr) {
 		int err = 0;
+
 		if (xattr && (flags & XATTR_CREATE))
 			err = -EEXIST;
 		else if (!xattr && (flags & XATTR_REPLACE))
@@ -399,12 +400,14 @@ static int __set_xattr(struct ceph_inode_info *ci,
 		if (err) {
 			kfree(name);
 			kfree(val);
+			kfree(*newxattr);
 			return err;
 		}
 		if (update_xattr < 0) {
 			if (xattr)
 				__remove_xattr(ci, xattr);
 			kfree(name);
+			kfree(*newxattr);
 			return 0;
 		}
 	}