Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Fix error output of boot instance creation failure

   Currently if a boot instance creation fails, instead of printing out
   the name of the instance that failed, it prints "(null)". That is
   because it prints "cur_str" that had already been processed by
   strsep(). Print the saved name instead.

   While at it, print the error code of the failure.

 - Fix use-after-free for same named historgrams

   Histograms can be named so that they can be used in multiple events.
   But if the named histogram has a variable attached, the second event
   that uses the named histogram which duplicates it and needs to free
   the original after duplication leaves the old variable in place and
   still visible. If another histogram uses than variable, it will use
   the stale one which will try to reference the freed duplicate
   histogram and crash the kernel.

   Free the duplicate variables along with the duplicated histogram
   data.

 - Check return value of kthread_run() in event self test

   The events self tests uses a kthread for testing but does not check
   if it succeeded in creating a kthread. If the kthread creation were
   to fail, the code will still try to call kthread_stop() on the error
   returned.

 - Fix race between reading trace_pipe and updating subbuffer size

   If a user is reading the trace_pipe file at the same time they update
   the ring buffer sub-buffer size, can cause the trace_pipe read to
   read stale data. Add trace_access_lock() around updating the ring
   buffer sub-buffer size.

 - Fix eventfs_inode on failure path in creation of the events directory

   In the creation of the "events" directory, if after allocating the
   eventfs_inode a failure is detected, it calls cleanup_ei() which
   calls free_ei(). The free_ei() will test if eventfs_inode being freed
   has no children. It is a bug if it does. But on the failure case of
   the creation of the "events" directory, the children lists have not
   yet been initialized and the free will trigger a warning because
   list_empty() on an uninitialized list returns false.

   Move the initialization into init_ei() where it makes more sense and
   makes sure that a created eventfs_inode has its lists initialized
   upon creation.

 - Check return value of kthread_run() in ftrace direct sample code

   The sample code that shows how to use the ftrace direct calls does
   not test the return of kthread_run() to see if it succeeds. Return a
   failure if the kthread_run() doesn't succeed.

 - Clear user events state on fork in case of alloc failure

   On fork, the child gets a pointer to the parent's user events state.
   It makes a copy of it then updates the child's pointer to it. But if
   the allocation fails, the duplication function leaves the child with
   a pointer to its parent's descriptor. When the child cleans up its
   data, it will free the parent's descriptor while the parent is still
   using it.

   In the duplication function, set the child's user_event_mm to NULL
   before testing if the allocation succeeded, and when it exits it will
   not free the parent's descriptor.

 - Fix retry exhaustion in simple ring buffer reader swap

   simple_ring_buffer_swap_reader_page() starts with retry set to 8 and
   post-decrements it only after a failed link replacement. On the final
   attempt, a successful replacement leaves retry at zero, while a
   failed replacement leaves it at -1.

   But the check for success expects the retry value to be non-zero and
   exits with an error on zero. This is the opposite result. Fix it.

 - Fail nicely when the remote swap_reader_page() returns an error

   Currently, if the swap_reader_page() of a remote buffer fails, it
   triggers a WARN_ON_ONCE() and continues normally. Instead, have it
   exit with an error and a pr_warn() print instead of a full WARNING.

* tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Stop remote reader update when page swap fails
  tracing: Fix retry exhaustion in simple ring buffer reader swap
  tracing/user_events: Clear copied tracing state before fork duplication
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify
  eventfs: Initialize ei->children and ei->list in init_ei()
  tracing: Fix use-after-free in trace_pipe read on sub-buffer order change
  tracing: Fix crash passing ERR_PTR to kthread_stop()
  tracing: Fix use-after-free with same-name named triggers
  tracing: Fix logged instance name on creation failure

1 files changed, 626 insertions, 0 deletions

diff --git a/fs/ceph/export.c b/fs/ceph/export.c
new file mode 100644
index 000000000..debb9634b
--- /dev/null
+++ b/fs/ceph/export.c
@@ -0,0 +1,626 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/ceph/ceph_debug.h>
+
+#include <linux/exportfs.h>
+#include <linux/slab.h>
+#include <linux/unaligned.h>
+
+#include "super.h"
+#include "mds_client.h"
+#include "crypto.h"
+
+/*
+ * Basic fh
+ */
+struct ceph_nfs_fh {
+	u64 ino;
+} __attribute__ ((packed));
+
+/*
+ * Larger fh that includes parent ino.
+ */
+struct ceph_nfs_confh {
+	u64 ino, parent_ino;
+} __attribute__ ((packed));
+
+/*
+ * fh for snapped inode
+ */
+struct ceph_nfs_snapfh {
+	u64 ino;
+	u64 snapid;
+	u64 parent_ino;
+	u32 hash;
+} __attribute__ ((packed));
+
+#define BYTES_PER_U32		(sizeof(u32))
+#define CEPH_FH_BASIC_SIZE \
+	(sizeof(struct ceph_nfs_fh) / BYTES_PER_U32)
+#define CEPH_FH_WITH_PARENT_SIZE \
+	(sizeof(struct ceph_nfs_confh) / BYTES_PER_U32)
+#define CEPH_FH_SNAPPED_INODE_SIZE \
+	(sizeof(struct ceph_nfs_snapfh) / BYTES_PER_U32)
+
+static int ceph_encode_snapfh(struct inode *inode, u32 *rawfh, int *max_len,
+			      struct inode *parent_inode)
+{
+	struct ceph_client *cl = ceph_inode_to_client(inode);
+	static const int snap_handle_length = CEPH_FH_SNAPPED_INODE_SIZE;
+	struct ceph_nfs_snapfh *sfh = (void *)rawfh;
+	u64 snapid = ceph_snap(inode);
+	int ret;
+	bool no_parent = true;
+
+	if (*max_len < snap_handle_length) {
+		*max_len = snap_handle_length;
+		ret = FILEID_INVALID;
+		goto out;
+	}
+
+	ret =  -EINVAL;
+	if (snapid != CEPH_SNAPDIR) {
+		struct inode *dir;
+		struct dentry *dentry = d_find_alias(inode);
+		if (!dentry)
+			goto out;
+
+		rcu_read_lock();
+		dir = d_inode_rcu(dentry->d_parent);
+		if (ceph_snap(dir) != CEPH_SNAPDIR) {
+			sfh->parent_ino = ceph_ino(dir);
+			sfh->hash = ceph_dentry_hash(dir, dentry);
+			no_parent = false;
+		}
+		rcu_read_unlock();
+		dput(dentry);
+	}
+
+	if (no_parent) {
+		if (!S_ISDIR(inode->i_mode))
+			goto out;
+		sfh->parent_ino = sfh->ino;
+		sfh->hash = 0;
+	}
+	sfh->ino = ceph_ino(inode);
+	sfh->snapid = snapid;
+
+	*max_len = snap_handle_length;
+	ret = FILEID_BTRFS_WITH_PARENT;
+out:
+	doutc(cl, "%p %llx.%llx ret=%d\n", inode, ceph_vinop(inode), ret);
+	return ret;
+}
+
+static int ceph_encode_fh(struct inode *inode, u32 *rawfh, int *max_len,
+			  struct inode *parent_inode)
+{
+	struct ceph_client *cl = ceph_inode_to_client(inode);
+	static const int handle_length = CEPH_FH_BASIC_SIZE;
+	static const int connected_handle_length = CEPH_FH_WITH_PARENT_SIZE;
+	int type;
+
+	if (ceph_snap(inode) != CEPH_NOSNAP)
+		return ceph_encode_snapfh(inode, rawfh, max_len, parent_inode);
+
+	if (parent_inode && (*max_len < connected_handle_length)) {
+		*max_len = connected_handle_length;
+		return FILEID_INVALID;
+	} else if (*max_len < handle_length) {
+		*max_len = handle_length;
+		return FILEID_INVALID;
+	}
+
+	if (parent_inode) {
+		struct ceph_nfs_confh *cfh = (void *)rawfh;
+		doutc(cl, "%p %llx.%llx with parent %p %llx.%llx\n", inode,
+		      ceph_vinop(inode), parent_inode, ceph_vinop(parent_inode));
+		cfh->ino = ceph_ino(inode);
+		cfh->parent_ino = ceph_ino(parent_inode);
+		*max_len = connected_handle_length;
+		type = FILEID_INO32_GEN_PARENT;
+	} else {
+		struct ceph_nfs_fh *fh = (void *)rawfh;
+		doutc(cl, "%p %llx.%llx\n", inode, ceph_vinop(inode));
+		fh->ino = ceph_ino(inode);
+		*max_len = handle_length;
+		type = FILEID_INO32_GEN;
+	}
+	return type;
+}
+
+static struct inode *__lookup_inode(struct super_block *sb, u64 ino)
+{
+	struct ceph_mds_client *mdsc = ceph_sb_to_fs_client(sb)->mdsc;
+	struct inode *inode;
+	struct ceph_vino vino;
+	int err;
+
+	vino.ino = ino;
+	vino.snap = CEPH_NOSNAP;
+
+	if (ceph_vino_is_reserved(vino))
+		return ERR_PTR(-ESTALE);
+
+	inode = ceph_find_inode(sb, vino);
+	if (!inode) {
+		struct ceph_mds_request *req;
+		int mask;
+
+		req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_LOOKUPINO,
+					       USE_ANY_MDS);
+		if (IS_ERR(req))
+			return ERR_CAST(req);
+
+		mask = CEPH_STAT_CAP_INODE;
+		if (ceph_security_xattr_wanted(d_inode(sb->s_root)))
+			mask |= CEPH_CAP_XATTR_SHARED;
+		req->r_args.lookupino.mask = cpu_to_le32(mask);
+
+		req->r_ino1 = vino;
+		req->r_num_caps = 1;
+		err = ceph_mdsc_do_request(mdsc, NULL, req);
+		inode = req->r_target_inode;
+		if (inode)
+			ihold(inode);
+		ceph_mdsc_put_request(req);
+		if (!inode)
+			return err < 0 ? ERR_PTR(err) : ERR_PTR(-ESTALE);
+	} else {
+		if (ceph_inode_is_shutdown(inode)) {
+			iput(inode);
+			return ERR_PTR(-ESTALE);
+		}
+	}
+	return inode;
+}
+
+struct inode *ceph_lookup_inode(struct super_block *sb, u64 ino)
+{
+	struct inode *inode = __lookup_inode(sb, ino);
+	if (IS_ERR(inode))
+		return inode;
+	if (inode->i_nlink == 0) {
+		iput(inode);
+		return ERR_PTR(-ESTALE);
+	}
+	return inode;
+}
+
+static struct dentry *__fh_to_dentry(struct super_block *sb, u64 ino)
+{
+	struct inode *inode = __lookup_inode(sb, ino);
+	struct ceph_inode_info *ci = ceph_inode(inode);
+	int err;
+
+	if (IS_ERR(inode))
+		return ERR_CAST(inode);
+	/* We need LINK caps to reliably check i_nlink */
+	err = ceph_do_getattr(inode, CEPH_CAP_LINK_SHARED, false);
+	if (err) {
+		iput(inode);
+		return ERR_PTR(err);
+	}
+	/* -ESTALE if inode as been unlinked and no file is open */
+	if ((inode->i_nlink == 0) && !__ceph_is_file_opened(ci)) {
+		iput(inode);
+		return ERR_PTR(-ESTALE);
+	}
+	return d_obtain_alias(inode);
+}
+
+static struct dentry *__snapfh_to_dentry(struct super_block *sb,
+					  struct ceph_nfs_snapfh *sfh,
+					  bool want_parent)
+{
+	struct ceph_mds_client *mdsc = ceph_sb_to_fs_client(sb)->mdsc;
+	struct ceph_client *cl = mdsc->fsc->client;
+	struct ceph_mds_request *req;
+	struct inode *inode;
+	struct ceph_vino vino;
+	int mask;
+	int err;
+	bool unlinked = false;
+
+	if (want_parent) {
+		vino.ino = sfh->parent_ino;
+		if (sfh->snapid == CEPH_SNAPDIR)
+			vino.snap = CEPH_NOSNAP;
+		else if (sfh->ino == sfh->parent_ino)
+			vino.snap = CEPH_SNAPDIR;
+		else
+			vino.snap = sfh->snapid;
+	} else {
+		vino.ino = sfh->ino;
+		vino.snap = sfh->snapid;
+	}
+
+	if (ceph_vino_is_reserved(vino))
+		return ERR_PTR(-ESTALE);
+
+	inode = ceph_find_inode(sb, vino);
+	if (inode) {
+		if (ceph_inode_is_shutdown(inode)) {
+			iput(inode);
+			return ERR_PTR(-ESTALE);
+		}
+		return d_obtain_alias(inode);
+	}
+
+	req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_LOOKUPINO,
+				       USE_ANY_MDS);
+	if (IS_ERR(req))
+		return ERR_CAST(req);
+
+	mask = CEPH_STAT_CAP_INODE;
+	if (ceph_security_xattr_wanted(d_inode(sb->s_root)))
+		mask |= CEPH_CAP_XATTR_SHARED;
+	req->r_args.lookupino.mask = cpu_to_le32(mask);
+	if (vino.snap < CEPH_NOSNAP) {
+		req->r_args.lookupino.snapid = cpu_to_le64(vino.snap);
+		if (!want_parent && sfh->ino != sfh->parent_ino) {
+			req->r_args.lookupino.parent =
+					cpu_to_le64(sfh->parent_ino);
+			req->r_args.lookupino.hash =
+					cpu_to_le32(sfh->hash);
+		}
+	}
+
+	req->r_ino1 = vino;
+	req->r_num_caps = 1;
+	err = ceph_mdsc_do_request(mdsc, NULL, req);
+	inode = req->r_target_inode;
+	if (inode) {
+		if (vino.snap == CEPH_SNAPDIR) {
+			if (inode->i_nlink == 0)
+				unlinked = true;
+			inode = ceph_get_snapdir(inode);
+		} else if (ceph_snap(inode) == vino.snap) {
+			ihold(inode);
+		} else {
+			/* mds does not support lookup snapped inode */
+			inode = ERR_PTR(-EOPNOTSUPP);
+		}
+	} else {
+		inode = ERR_PTR(-ESTALE);
+	}
+	ceph_mdsc_put_request(req);
+
+	if (want_parent) {
+		doutc(cl, "%llx.%llx\n err=%d\n", vino.ino, vino.snap, err);
+	} else {
+		doutc(cl, "%llx.%llx parent %llx hash %x err=%d", vino.ino,
+		      vino.snap, sfh->parent_ino, sfh->hash, err);
+	}
+	/* see comments in ceph_get_parent() */
+	return unlinked ? d_obtain_root(inode) : d_obtain_alias(inode);
+}
+
+/*
+ * convert regular fh to dentry
+ */
+static struct dentry *ceph_fh_to_dentry(struct super_block *sb,
+					struct fid *fid,
+					int fh_len, int fh_type)
+{
+	struct ceph_fs_client *fsc = ceph_sb_to_fs_client(sb);
+	struct ceph_nfs_fh *fh = (void *)fid->raw;
+
+	if (fh_type == FILEID_BTRFS_WITH_PARENT) {
+		struct ceph_nfs_snapfh *sfh = (void *)fid->raw;
+		return __snapfh_to_dentry(sb, sfh, false);
+	}
+
+	if (fh_type != FILEID_INO32_GEN  &&
+	    fh_type != FILEID_INO32_GEN_PARENT)
+		return NULL;
+	if (fh_len < sizeof(*fh) / BYTES_PER_U32)
+		return NULL;
+
+	doutc(fsc->client, "%llx\n", fh->ino);
+	return __fh_to_dentry(sb, fh->ino);
+}
+
+static struct dentry *__get_parent(struct super_block *sb,
+				   struct dentry *child, u64 ino)
+{
+	struct ceph_mds_client *mdsc = ceph_sb_to_fs_client(sb)->mdsc;
+	struct ceph_mds_request *req;
+	struct inode *inode;
+	int mask;
+	int err;
+
+	req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_LOOKUPPARENT,
+				       USE_ANY_MDS);
+	if (IS_ERR(req))
+		return ERR_CAST(req);
+
+	if (child) {
+		req->r_inode = d_inode(child);
+		ihold(d_inode(child));
+	} else {
+		req->r_ino1 = (struct ceph_vino) {
+			.ino = ino,
+			.snap = CEPH_NOSNAP,
+		};
+	}
+
+	mask = CEPH_STAT_CAP_INODE;
+	if (ceph_security_xattr_wanted(d_inode(sb->s_root)))
+		mask |= CEPH_CAP_XATTR_SHARED;
+	req->r_args.getattr.mask = cpu_to_le32(mask);
+
+	req->r_num_caps = 1;
+	err = ceph_mdsc_do_request(mdsc, NULL, req);
+	if (err) {
+		ceph_mdsc_put_request(req);
+		return ERR_PTR(err);
+	}
+
+	inode = req->r_target_inode;
+	if (inode)
+		ihold(inode);
+	ceph_mdsc_put_request(req);
+	if (!inode)
+		return ERR_PTR(-ENOENT);
+
+	return d_obtain_alias(inode);
+}
+
+static struct dentry *ceph_get_parent(struct dentry *child)
+{
+	struct inode *inode = d_inode(child);
+	struct ceph_client *cl = ceph_inode_to_client(inode);
+	struct dentry *dn;
+
+	if (ceph_snap(inode) != CEPH_NOSNAP) {
+		struct inode* dir;
+		bool unlinked = false;
+		/* do not support non-directory */
+		if (!d_is_dir(child)) {
+			dn = ERR_PTR(-EINVAL);
+			goto out;
+		}
+		dir = __lookup_inode(inode->i_sb, ceph_ino(inode));
+		if (IS_ERR(dir)) {
+			dn = ERR_CAST(dir);
+			goto out;
+		}
+		/* There can be multiple paths to access snapped inode.
+		 * For simplicity, treat snapdir of head inode as parent */
+		if (ceph_snap(inode) != CEPH_SNAPDIR) {
+			struct inode *snapdir = ceph_get_snapdir(dir);
+			if (dir->i_nlink == 0)
+				unlinked = true;
+			iput(dir);
+			if (IS_ERR(snapdir)) {
+				dn = ERR_CAST(snapdir);
+				goto out;
+			}
+			dir = snapdir;
+		}
+		/* If directory has already been deleted, further get_parent
+		 * will fail. Do not mark snapdir dentry as disconnected,
+		 * this prevents exportfs from doing further get_parent. */
+		if (unlinked)
+			dn = d_obtain_root(dir);
+		else
+			dn = d_obtain_alias(dir);
+	} else {
+		dn = __get_parent(child->d_sb, child, 0);
+	}
+out:
+	doutc(cl, "child %p %p %llx.%llx err=%ld\n", child, inode,
+	      ceph_vinop(inode), (long)PTR_ERR_OR_ZERO(dn));
+	return dn;
+}
+
+/*
+ * convert regular fh to parent
+ */
+static struct dentry *ceph_fh_to_parent(struct super_block *sb,
+					struct fid *fid,
+					int fh_len, int fh_type)
+{
+	struct ceph_fs_client *fsc = ceph_sb_to_fs_client(sb);
+	struct ceph_nfs_confh *cfh = (void *)fid->raw;
+	struct dentry *dentry;
+
+	if (fh_type == FILEID_BTRFS_WITH_PARENT) {
+		struct ceph_nfs_snapfh *sfh = (void *)fid->raw;
+		return __snapfh_to_dentry(sb, sfh, true);
+	}
+
+	if (fh_type != FILEID_INO32_GEN_PARENT)
+		return NULL;
+	if (fh_len < sizeof(*cfh) / BYTES_PER_U32)
+		return NULL;
+
+	doutc(fsc->client, "%llx\n", cfh->parent_ino);
+	dentry = __get_parent(sb, NULL, cfh->ino);
+	if (unlikely(dentry == ERR_PTR(-ENOENT)))
+		dentry = __fh_to_dentry(sb, cfh->parent_ino);
+	return dentry;
+}
+
+static int ceph_export_copy_name(char *name, const char *src, u32 len)
+{
+	if (len > NAME_MAX)
+		return -ENAMETOOLONG;
+
+	memcpy(name, src, len);
+	name[len] = '\0';
+	return 0;
+}
+
+static int __get_snap_name(struct dentry *parent, char *name,
+			   struct dentry *child)
+{
+	struct inode *inode = d_inode(child);
+	struct inode *dir = d_inode(parent);
+	struct ceph_fs_client *fsc = ceph_inode_to_fs_client(inode);
+	struct ceph_mds_request *req = NULL;
+	char *last_name = NULL;
+	unsigned next_offset = 2;
+	int err = -EINVAL;
+
+	if (ceph_ino(inode) != ceph_ino(dir))
+		goto out;
+	if (ceph_snap(inode) == CEPH_SNAPDIR) {
+		if (ceph_snap(dir) == CEPH_NOSNAP) {
+			/*
+			 * .get_name() from struct export_operations
+			 * assumes that its 'name' parameter is pointing
+			 * to a NAME_MAX+1 sized buffer
+			 */
+			strscpy(name, fsc->mount_options->snapdir_name,
+				NAME_MAX + 1);
+			err = 0;
+		}
+		goto out;
+	}
+	if (ceph_snap(dir) != CEPH_SNAPDIR)
+		goto out;
+
+	while (1) {
+		struct ceph_mds_reply_info_parsed *rinfo;
+		struct ceph_mds_reply_dir_entry *rde;
+		int i;
+
+		req = ceph_mdsc_create_request(fsc->mdsc, CEPH_MDS_OP_LSSNAP,
+					       USE_AUTH_MDS);
+		if (IS_ERR(req)) {
+			err = PTR_ERR(req);
+			req = NULL;
+			goto out;
+		}
+		err = ceph_alloc_readdir_reply_buffer(req, inode);
+		if (err)
+			goto out;
+
+		req->r_direct_mode = USE_AUTH_MDS;
+		req->r_readdir_offset = next_offset;
+		req->r_args.readdir.flags =
+				cpu_to_le16(CEPH_READDIR_REPLY_BITFLAGS);
+		if (last_name) {
+			req->r_path2 = last_name;
+			last_name = NULL;
+		}
+
+		req->r_inode = dir;
+		ihold(dir);
+		req->r_dentry = dget(parent);
+
+		inode_lock(dir);
+		err = ceph_mdsc_do_request(fsc->mdsc, NULL, req);
+		inode_unlock(dir);
+
+		if (err < 0)
+			goto out;
+
+		rinfo = &req->r_reply_info;
+		for (i = 0; i < rinfo->dir_nr; i++) {
+			rde = rinfo->dir_entries + i;
+			BUG_ON(!rde->inode.in);
+			if (ceph_snap(inode) ==
+			    le64_to_cpu(rde->inode.in->snapid)) {
+				err = ceph_export_copy_name(name, rde->name,
+							    rde->name_len);
+				goto out;
+			}
+		}
+
+		if (rinfo->dir_end)
+			break;
+
+		BUG_ON(rinfo->dir_nr <= 0);
+		rde = rinfo->dir_entries + (rinfo->dir_nr - 1);
+		next_offset += rinfo->dir_nr;
+		last_name = kstrndup(rde->name, rde->name_len, GFP_KERNEL);
+		if (!last_name) {
+			err = -ENOMEM;
+			goto out;
+		}
+
+		ceph_mdsc_put_request(req);
+		req = NULL;
+	}
+	err = -ENOENT;
+out:
+	if (req)
+		ceph_mdsc_put_request(req);
+	kfree(last_name);
+	doutc(fsc->client, "child dentry %p %p %llx.%llx err=%d\n", child,
+	      inode, ceph_vinop(inode), err);
+	return err;
+}
+
+static int ceph_get_name(struct dentry *parent, char *name,
+			 struct dentry *child)
+{
+	struct ceph_mds_client *mdsc;
+	struct ceph_mds_request *req;
+	struct inode *dir = d_inode(parent);
+	struct inode *inode = d_inode(child);
+	struct ceph_mds_reply_info_parsed *rinfo;
+	int err;
+
+	if (ceph_snap(inode) != CEPH_NOSNAP)
+		return __get_snap_name(parent, name, child);
+
+	mdsc = ceph_inode_to_fs_client(inode)->mdsc;
+	req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_LOOKUPNAME,
+				       USE_ANY_MDS);
+	if (IS_ERR(req))
+		return PTR_ERR(req);
+
+	inode_lock(dir);
+	req->r_inode = inode;
+	ihold(inode);
+	req->r_ino2 = ceph_vino(d_inode(parent));
+	req->r_parent = dir;
+	ihold(dir);
+	set_bit(CEPH_MDS_R_PARENT_LOCKED, &req->r_req_flags);
+	req->r_num_caps = 2;
+	err = ceph_mdsc_do_request(mdsc, NULL, req);
+	inode_unlock(dir);
+
+	if (err)
+		goto out;
+
+	rinfo = &req->r_reply_info;
+	if (!IS_ENCRYPTED(dir)) {
+		err = ceph_export_copy_name(name, rinfo->dname,
+					    rinfo->dname_len);
+	} else {
+		struct fscrypt_str oname = FSTR_INIT(NULL, 0);
+		struct ceph_fname fname = { .dir	= dir,
+					    .name	= rinfo->dname,
+					    .ctext	= rinfo->altname,
+					    .name_len	= rinfo->dname_len,
+					    .ctext_len	= rinfo->altname_len };
+
+		err = ceph_fname_alloc_buffer(dir, &oname);
+		if (err < 0)
+			goto out;
+
+		err = ceph_fname_to_usr(&fname, NULL, &oname, NULL);
+		if (!err)
+			err = ceph_export_copy_name(name, oname.name,
+						    oname.len);
+		ceph_fname_free_buffer(dir, &oname);
+	}
+out:
+	doutc(mdsc->fsc->client, "child dentry %p %p %llx.%llx err %d %s%s\n",
+	      child, inode, ceph_vinop(inode), err, err ? "" : "name ",
+	      err ? "" : name);
+	ceph_mdsc_put_request(req);
+	return err;
+}
+
+const struct export_operations ceph_export_ops = {
+	.encode_fh = ceph_encode_fh,
+	.fh_to_dentry = ceph_fh_to_dentry,
+	.fh_to_parent = ceph_fh_to_parent,
+	.get_parent = ceph_get_parent,
+	.get_name = ceph_get_name,
+};