Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull vfs updates from Al Viro:
 "Stuff in here:

   - acct.c fixes and general rework of mnt_pin mechanism.  That allows
     to go for delayed-mntput stuff, which will permit mntput() on deep
     stack without worrying about stack overflows - fs shutdown will
     happen on shallow stack.  IOW, we can do Eric's umount-on-rmdir
     series without introducing tons of stack overflows on new mntput()
     call chains it introduces.
   - Bruce's d_splice_alias() patches
   - more Miklos' rename() stuff.
   - a couple of regression fixes (stable fodder, in the end of branch)
     and a fix for API idiocy in iov_iter.c.

  There definitely will be another pile, maybe even two.  I'd like to
  get Eric's series in this time, but even if we miss it, it'll go right
  in the beginning of for-next in the next cycle - the tricky part of
  prereqs is in this pile"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (40 commits)
  fix copy_tree() regression
  __generic_file_write_iter(): fix handling of sync error after DIO
  switch iov_iter_get_pages() to passing maximal number of pages
  fs: mark __d_obtain_alias static
  dcache: d_splice_alias should detect loops
  exportfs: update Exporting documentation
  dcache: d_find_alias needn't recheck IS_ROOT && DCACHE_DISCONNECTED
  dcache: remove unused d_find_alias parameter
  dcache: d_obtain_alias callers don't all want DISCONNECTED
  dcache: d_splice_alias should ignore DCACHE_DISCONNECTED
  dcache: d_splice_alias mustn't create directory aliases
  dcache: close d_move race in d_splice_alias
  dcache: move d_splice_alias
  namei: trivial fix to vfs_rename_dir comment
  VFS: allow ->d_manage() to declare -EISDIR in rcu_walk mode.
  cifs: support RENAME_NOREPLACE
  hostfs: support rename flags
  shmem: support RENAME_EXCHANGE
  shmem: support RENAME_NOREPLACE
  btrfs: add RENAME_NOREPLACE
  ...

36 files changed, 645 insertions, 465 deletions

diff --git a/Documentation/filesystems/nfs/Exporting b/Documentation/filesystems/nfs/Exporting
index e543b1a619cc..c8f036a9b13f 100644
--- a/Documentation/filesystems/nfs/Exporting
+++ b/Documentation/filesystems/nfs/Exporting
@@ -66,23 +66,31 @@ b/ A per-superblock list "s_anon" of dentries which are the roots of
 
 c/ Helper routines to allocate anonymous dentries, and to help attach
    loose directory dentries at lookup time. They are:
-    d_alloc_anon(inode) will return a dentry for the given inode.
+    d_obtain_alias(inode) will return a dentry for the given inode.
       If the inode already has a dentry, one of those is returned.
       If it doesn't, a new anonymous (IS_ROOT and
         DCACHE_DISCONNECTED) dentry is allocated and attached.
       In the case of a directory, care is taken that only one dentry
       can ever be attached.
-    d_splice_alias(inode, dentry) will make sure that there is a
-      dentry with the same name and parent as the given dentry, and
-      which refers to the given inode.
-      If the inode is a directory and already has a dentry, then that
-      dentry is d_moved over the given dentry.
-      If the passed dentry gets attached, care is taken that this is
-      mutually exclusive to a d_alloc_anon operation.
-      If the passed dentry is used, NULL is returned, else the used
-      dentry is returned.  This corresponds to the calling pattern of
-      ->lookup.
-  
+    d_splice_alias(inode, dentry) or d_materialise_unique(dentry, inode)
+      will introduce a new dentry into the tree; either the passed-in
+      dentry or a preexisting alias for the given inode (such as an
+      anonymous one created by d_obtain_alias), if appropriate.  The two
+      functions differ in their handling of directories with preexisting
+      aliases:
+        d_splice_alias will use any existing IS_ROOT dentry, but it will
+	  return -EIO rather than try to move a dentry with a different
+	  parent.  This is appropriate for local filesystems, which
+	  should never see such an alias unless the filesystem is
+	  corrupted somehow (for example, if two on-disk directory
+	  entries refer to the same directory.)
+	d_materialise_unique will attempt to move any dentry.  This is
+	  appropriate for distributed filesystems, where finding a
+	  directory other than where we last cached it may be a normal
+	  consequence of concurrent operations on other hosts.
+      Both functions return NULL when the passed-in dentry is used,
+      following the calling convention of ->lookup.
+
  
 Filesystem Issues
 -----------------
@@ -120,12 +128,12 @@ struct which has the following members:
 
   fh_to_dentry (mandatory)
     Given a filehandle fragment, this should find the implied object and
-    create a dentry for it (possibly with d_alloc_anon).
+    create a dentry for it (possibly with d_obtain_alias).
 
   fh_to_parent (optional but strongly recommended)
     Given a filehandle fragment, this should find the parent of the
-    implied object and create a dentry for it (possibly with d_alloc_anon).
-    May fail if the filehandle fragment is too small.
+    implied object and create a dentry for it (possibly with
+    d_obtain_alias).  May fail if the filehandle fragment is too small.
 
   get_parent (optional but strongly recommended)
     When given a dentry for a directory, this should return  a dentry for
diff --git a/Documentation/filesystems/vfs.txt b/Documentation/filesystems/vfs.txt
index a1d0d7a30165..61d65cc65c54 100644
--- a/Documentation/filesystems/vfs.txt
+++ b/Documentation/filesystems/vfs.txt
@@ -1053,7 +1053,8 @@ struct dentry_operations {
 	If the 'rcu_walk' parameter is true, then the caller is doing a
 	pathwalk in RCU-walk mode.  Sleeping is not permitted in this mode,
 	and the caller can be asked to leave it and call again by returning
-	-ECHILD.
+	-ECHILD.  -EISDIR may also be returned to tell pathwalk to
+	ignore d_automount or any mounts.
 
 	This function is only used if DCACHE_MANAGE_TRANSIT is set on the
 	dentry being transited from.
diff --git a/fs/Makefile b/fs/Makefile
index 4030cbfbc9af..90c88529892b 100644
--- a/fs/Makefile
+++ b/fs/Makefile
@@ -11,7 +11,7 @@ obj-y :=	open.o read_write.o file_table.o super.o \
 		attr.o bad_inode.o file.o filesystems.o namespace.o \
 		seq_file.o xattr.o libfs.o fs-writeback.o \
 		pnode.o splice.o sync.o utimes.o \
-		stack.o fs_struct.o statfs.o
+		stack.o fs_struct.o statfs.o fs_pin.o
 
 ifeq ($(CONFIG_BLOCK),y)
 obj-y +=	buffer.o block_dev.o direct-io.o mpage.o
diff --git a/fs/bad_inode.c b/fs/bad_inode.c
index 7c93953030fb..afd2b4408adf 100644
--- a/fs/bad_inode.c
+++ b/fs/bad_inode.c
@@ -218,8 +218,9 @@ static int bad_inode_mknod (struct inode *dir, struct dentry *dentry,
 	return -EIO;
 }
 
-static int bad_inode_rename (struct inode *old_dir, struct dentry *old_dentry,
-		struct inode *new_dir, struct dentry *new_dentry)
+static int bad_inode_rename2(struct inode *old_dir, struct dentry *old_dentry,
+			     struct inode *new_dir, struct dentry *new_dentry,
+			     unsigned int flags)
 {
 	return -EIO;
 }
@@ -279,7 +280,7 @@ static const struct inode_operations bad_inode_ops =
 	.mkdir		= bad_inode_mkdir,
 	.rmdir		= bad_inode_rmdir,
 	.mknod		= bad_inode_mknod,
-	.rename		= bad_inode_rename,
+	.rename2	= bad_inode_rename2,
 	.readlink	= bad_inode_readlink,
 	/* follow_link must be no-op, otherwise unmounting this inode
 	   won't work */
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 3668048e16f8..3183742d6f0d 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -8476,6 +8476,16 @@ out_notrans:
 	return ret;
 }
 
+static int btrfs_rename2(struct inode *old_dir, struct dentry *old_dentry,
+			 struct inode *new_dir, struct dentry *new_dentry,
+			 unsigned int flags)
+{
+	if (flags & ~RENAME_NOREPLACE)
+		return -EINVAL;
+
+	return btrfs_rename(old_dir, old_dentry, new_dir, new_dentry);
+}
+
 static void btrfs_run_delalloc_work(struct btrfs_work *work)
 {
 	struct btrfs_delalloc_work *delalloc_work;
@@ -9019,7 +9029,7 @@ static const struct inode_operations btrfs_dir_inode_operations = {
 	.link		= btrfs_link,
 	.mkdir		= btrfs_mkdir,
 	.rmdir		= btrfs_rmdir,
-	.rename		= btrfs_rename,
+	.rename2	= btrfs_rename2,
 	.symlink	= btrfs_symlink,
 	.setattr	= btrfs_setattr,
 	.mknod		= btrfs_mknod,
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 8e16bca69c56..67b48b9a03e0 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -851,7 +851,6 @@ static struct dentry *get_default_root(struct super_block *sb,
 	struct btrfs_path *path;
 	struct btrfs_key location;
 	struct inode *inode;
-	struct dentry *dentry;
 	u64 dir_id;
 	int new = 0;
 
@@ -922,13 +921,7 @@ setup_root:
 		return dget(sb->s_root);
 	}
 
-	dentry = d_obtain_alias(inode);
-	if (!IS_ERR(dentry)) {
-		spin_lock(&dentry->d_lock);
-		dentry->d_flags &= ~DCACHE_DISCONNECTED;
-		spin_unlock(&dentry->d_lock);
-	}
-	return dentry;
+	return d_obtain_root(inode);
 }
 
 static int btrfs_fill_super(struct super_block *sb,
diff --git a/fs/ceph/super.c b/fs/ceph/super.c
index 06150fd745ac..f6e12377335c 100644
--- a/fs/ceph/super.c
+++ b/fs/ceph/super.c
@@ -755,7 +755,7 @@ static struct dentry *open_root_dentry(struct ceph_fs_client *fsc,
 				goto out;
 			}
 		} else {
-			root = d_obtain_alias(inode);
+			root = d_obtain_root(inode);
 		}
 		ceph_init_dentry(root);
 		dout("open_root_inode success, root dentry is %p\n", root);
diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
index 888398067420..ac4f260155c8 100644
--- a/fs/cifs/cifsfs.c
+++ b/fs/cifs/cifsfs.c
@@ -848,7 +848,7 @@ const struct inode_operations cifs_dir_inode_ops = {
 	.link = cifs_hardlink,
 	.mkdir = cifs_mkdir,
 	.rmdir = cifs_rmdir,
-	.rename = cifs_rename,
+	.rename2 = cifs_rename2,
 	.permission = cifs_permission,
 /*	revalidate:cifs_revalidate,   */
 	.setattr = cifs_setattr,
diff --git a/fs/cifs/cifsfs.h b/fs/cifs/cifsfs.h
index 560480263336..b0fafa499505 100644
--- a/fs/cifs/cifsfs.h
+++ b/fs/cifs/cifsfs.h
@@ -68,8 +68,8 @@ extern int cifs_hardlink(struct dentry *, struct inode *, struct dentry *);
 extern int cifs_mknod(struct inode *, struct dentry *, umode_t, dev_t);
 extern int cifs_mkdir(struct inode *, struct dentry *, umode_t);
 extern int cifs_rmdir(struct inode *, struct dentry *);
-extern int cifs_rename(struct inode *, struct dentry *, struct inode *,
-		       struct dentry *);
+extern int cifs_rename2(struct inode *, struct dentry *, struct inode *,
+			struct dentry *, unsigned int);
 extern int cifs_revalidate_file_attr(struct file *filp);
 extern int cifs_revalidate_dentry_attr(struct dentry *);
 extern int cifs_revalidate_file(struct file *filp);
diff --git a/fs/cifs/inode.c b/fs/cifs/inode.c
index 41de3935caa0..426d6c6ad8bf 100644
--- a/fs/cifs/inode.c
+++ b/fs/cifs/inode.c
@@ -1627,8 +1627,9 @@ do_rename_exit:
 }
 
 int
-cifs_rename(struct inode *source_dir, struct dentry *source_dentry,
-	    struct inode *target_dir, struct dentry *target_dentry)
+cifs_rename2(struct inode *source_dir, struct dentry *source_dentry,
+	     struct inode *target_dir, struct dentry *target_dentry,
+	     unsigned int flags)
 {
 	char *from_name = NULL;
 	char *to_name = NULL;
@@ -1640,6 +1641,9 @@ cifs_rename(struct inode *source_dir, struct dentry *source_dentry,
 	unsigned int xid;
 	int rc, tmprc;
 
+	if (flags & ~RENAME_NOREPLACE)
+		return -EINVAL;
+
 	cifs_sb = CIFS_SB(source_dir->i_sb);
 	tlink = cifs_sb_tlink(cifs_sb);
 	if (IS_ERR(tlink))
@@ -1667,6 +1671,12 @@ cifs_rename(struct inode *source_dir, struct dentry *source_dentry,
 	rc = cifs_do_rename(xid, source_dentry, from_name, target_dentry,
 			    to_name);
 
+	/*
+	 * No-replace is the natural behavior for CIFS, so skip unlink hacks.
+	 */
+	if (flags & RENAME_NOREPLACE)
+		goto cifs_rename_exit;
+
 	if (rc == -EEXIST && tcon->unix_ext) {
 		/*
 		 * Are src and dst hardlinks of same inode? We can only tell
diff --git a/fs/dcache.c b/fs/dcache.c
index 06f65857a855..d30ce699ae4b 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -731,8 +731,6 @@ EXPORT_SYMBOL(dget_parent);
 /**
  * d_find_alias - grab a hashed alias of inode
  * @inode: inode in question
- * @want_discon:  flag, used by d_splice_alias, to request
- *          that only a DISCONNECTED alias be returned.
  *
  * If inode has a hashed alias, or is a directory and has any alias,
  * acquire the reference to alias and return it. Otherwise return NULL.
@@ -741,10 +739,9 @@ EXPORT_SYMBOL(dget_parent);
  * of a filesystem.
  *
  * If the inode has an IS_ROOT, DCACHE_DISCONNECTED alias, then prefer
- * any other hashed alias over that one unless @want_discon is set,
- * in which case only return an IS_ROOT, DCACHE_DISCONNECTED alias.
+ * any other hashed alias over that one.
  */
-static struct dentry *__d_find_alias(struct inode *inode, int want_discon)
+static struct dentry *__d_find_alias(struct inode *inode)
 {
 	struct dentry *alias, *discon_alias;
 
@@ -756,7 +753,7 @@ again:
 			if (IS_ROOT(alias) &&
 			    (alias->d_flags & DCACHE_DISCONNECTED)) {
 				discon_alias = alias;
-			} else if (!want_discon) {
+			} else {
 				__dget_dlock(alias);
 				spin_unlock(&alias->d_lock);
 				return alias;
@@ -768,12 +765,9 @@ again:
 		alias = discon_alias;
 		spin_lock(&alias->d_lock);
 		if (S_ISDIR(inode->i_mode) || !d_unhashed(alias)) {
-			if (IS_ROOT(alias) &&
-			    (alias->d_flags & DCACHE_DISCONNECTED)) {
-				__dget_dlock(alias);
-				spin_unlock(&alias->d_lock);
-				return alias;
-			}
+			__dget_dlock(alias);
+			spin_unlock(&alias->d_lock);
+			return alias;
 		}
 		spin_unlock(&alias->d_lock);
 		goto again;
@@ -787,7 +781,7 @@ struct dentry *d_find_alias(struct inode *inode)
 
 	if (!hlist_empty(&inode->i_dentry)) {
 		spin_lock(&inode->i_lock);
-		de = __d_find_alias(inode, 0);
+		de = __d_find_alias(inode);
 		spin_unlock(&inode->i_lock);
 	}
 	return de;
@@ -1781,25 +1775,7 @@ struct dentry *d_find_any_alias(struct inode *inode)
 }
 EXPORT_SYMBOL(d_find_any_alias);
 
-/**
- * d_obtain_alias - find or allocate a dentry for a given inode
- * @inode: inode to allocate the dentry for
- *
- * Obtain a dentry for an inode resulting from NFS filehandle conversion or
- * similar open by handle operations.  The returned dentry may be anonymous,
- * or may have a full name (if the inode was already in the cache).
- *
- * When called on a directory inode, we must ensure that the inode only ever
- * has one dentry.  If a dentry is found, that is returned instead of
- * allocating a new one.
- *
- * On successful return, the reference to the inode has been transferred
- * to the dentry.  In case of an error the reference on the inode is released.
- * To make it easier to use in export operations a %NULL or IS_ERR inode may
- * be passed in and will be the error will be propagate to the return value,
- * with a %NULL @inode replaced by ERR_PTR(-ESTALE).
- */
-struct dentry *d_obtain_alias(struct inode *inode)
+static struct dentry *__d_obtain_alias(struct inode *inode, int disconnected)
 {
 	static const struct qstr anonstring = QSTR_INIT("/", 1);
 	struct dentry *tmp;
@@ -1830,7 +1806,10 @@ struct dentry *d_obtain_alias(struct inode *inode)
 	}
 
 	/* attach a disconnected dentry */
-	add_flags = d_flags_for_inode(inode) | DCACHE_DISCONNECTED;
+	add_flags = d_flags_for_inode(inode);
+
+	if (disconnected)
+		add_flags |= DCACHE_DISCONNECTED;
 
 	spin_lock(&tmp->d_lock);
 	tmp->d_inode = inode;
@@ -1851,59 +1830,51 @@ struct dentry *d_obtain_alias(struct inode *inode)
 	iput(inode);
 	return res;
 }
-EXPORT_SYMBOL(d_obtain_alias);
 
 /**
- * d_splice_alias - splice a disconnected dentry into the tree if one exists
- * @inode:  the inode which may have a disconnected dentry
- * @dentry: a negative dentry which we want to point to the inode.
- *
- * If inode is a directory and has a 'disconnected' dentry (i.e. IS_ROOT and
- * DCACHE_DISCONNECTED), then d_move that in place of the given dentry
- * and return it, else simply d_add the inode to the dentry and return NULL.
+ * d_obtain_alias - find or allocate a DISCONNECTED dentry for a given inode
+ * @inode: inode to allocate the dentry for
  *
- * This is needed in the lookup routine of any filesystem that is exportable
- * (via knfsd) so that we can build dcache paths to directories effectively.
+ * Obtain a dentry for an inode resulting from NFS filehandle conversion or
+ * similar open by handle operations.  The returned dentry may be anonymous,
+ * or may have a full name (if the inode was already in the cache).
  *
- * If a dentry was found and moved, then it is returned.  Otherwise NULL
- * is returned.  This matches the expected return value of ->lookup.
+ * When called on a directory inode, we must ensure that the inode only ever
+ * has one dentry.  If a dentry is found, that is returned instead of
+ * allocating a new one.
  *
- * Cluster filesystems may call this function with a negative, hashed dentry.
- * In that case, we know that the inode will be a regular file, and also this
- * will only occur during atomic_open. So we need to check for the dentry
- * being already hashed only in the final case.
+ * On successful return, the reference to the inode has been transferred
+ * to the dentry.  In case of an error the reference on the inode is released.
+ * To make it easier to use in export operations a %NULL or IS_ERR inode may
+ * be passed in and the error will be propagated to the return value,
+ * with a %NULL @inode replaced by ERR_PTR(-ESTALE).
  */
-struct dentry *d_splice_alias(struct inode *inode, struct dentry *dentry)
+struct dentry *d_obtain_alias(struct inode *inode)
 {
-	struct dentry *new = NULL;
-
-	if (IS_ERR(inode))
-		return ERR_CAST(inode);
+	return __d_obtain_alias(inode, 1);
+}
+EXPORT_SYMBOL(d_obtain_alias);
 
-	if (inode && S_ISDIR(inode->i_mode)) {
-		spin_lock(&inode->i_lock);
-		new = __d_find_alias(inode, 1);
-		if (new) {
-			BUG_ON(!(new->d_flags & DCACHE_DISCONNECTED));
-			spin_unlock(&inode->i_lock);
-			security_d_instantiate(new, inode);
-			d_move(new, dentry);
-			iput(inode);
-		} else {
-			/* already taking inode->i_lock, so d_add() by hand */
-			__d_instantiate(dentry, inode);
-			spin_unlock(&inode->i_lock);
-			security_d_instantiate(dentry, inode);
-			d_rehash(dentry);
-		}
-	} else {
-		d_instantiate(dentry, inode);
-		if (d_unhashed(dentry))
-			d_rehash(dentry);
-	}
-	return new;
+/**
+ * d_obtain_root - find or allocate a dentry for a given inode
+ * @inode: inode to allocate the dentry for
+ *
+ * Obtain an IS_ROOT dentry for the root of a filesystem.
+ *
+ * We must ensure that directory inodes only ever have one dentry.  If a
+ * dentry is found, that is returned instead of allocating a new one.
+ *
+ * On successful return, the reference to the inode has been transferred
+ * to the dentry.  In case of an error the reference on the inode is
+ * released.  A %NULL or IS_ERR inode may be passed in and will be the
+ * error will be propagate to the return value, with a %NULL @inode
+ * replaced by ERR_PTR(-ESTALE).
+ */
+struct dentry *d_obtain_root(struct inode *inode)
+{
+	return __d_obtain_alias(inode, 0);
 }
-EXPORT_SYMBOL(d_splice_alias);
+EXPORT_SYMBOL(d_obtain_root);
 
 /**
  * d_add_ci - lookup or allocate new dentry with case-exact name
@@ -2697,6 +2668,75 @@ static void __d_materialise_dentry(struct dentry *dentry, struct dentry *anon)
 }
 
 /**
+ * d_splice_alias - splice a disconnected dentry into the tree if one exists
+ * @inode:  the inode which may have a disconnected dentry
+ * @dentry: a negative dentry which we want to point to the inode.
+ *
+ * If inode is a directory and has an IS_ROOT alias, then d_move that in
+ * place of the given dentry and return it, else simply d_add the inode
+ * to the dentry and return NULL.
+ *
+ * If a non-IS_ROOT directory is found, the filesystem is corrupt, and
+ * we should error out: directories can't have multiple aliases.
+ *
+ * This is needed in the lookup routine of any filesystem that is exportable
+ * (via knfsd) so that we can build dcache paths to directories effectively.
+ *
+ * If a dentry was found and moved, then it is returned.  Otherwise NULL
+ * is returned.  This matches the expected return value of ->lookup.
+ *
+ * Cluster filesystems may call this function with a negative, hashed dentry.
+ * In that case, we know that the inode will be a regular file, and also this
+ * will only occur during atomic_open. So we need to check for the dentry
+ * being already hashed only in the final case.
+ */
+struct dentry *d_splice_alias(struct inode *inode, struct dentry *dentry)
+{
+	struct dentry *new = NULL;
+
+	if (IS_ERR(inode))
+		return ERR_CAST(inode);
+
+	if (inode && S_ISDIR(inode->i_mode)) {
+		spin_lock(&inode->i_lock);
+		new = __d_find_any_alias(inode);
+		if (new) {
+			if (!IS_ROOT(new)) {
+				spin_unlock(&inode->i_lock);
+				dput(new);
+				return ERR_PTR(-EIO);
+			}
+			if (d_ancestor(new, dentry)) {
+				spin_unlock(&inode->i_lock);
+				dput(new);
+				return ERR_PTR(-EIO);
+			}
+			write_seqlock(&rename_lock);
+			__d_materialise_dentry(dentry, new);
+			write_sequnlock(&rename_lock);
+			__d_drop(new);
+			_d_rehash(new);
+			spin_unlock(&new->d_lock);
+			spin_unlock(&inode->i_lock);
+			security_d_instantiate(new, inode);
+			iput(inode);
+		} else {
+			/* already taking inode->i_lock, so d_add() by hand */
+			__d_instantiate(dentry, inode);
+			spin_unlock(&inode->i_lock);
+			security_d_instantiate(dentry, inode);
+			d_rehash(dentry);
+		}
+	} else {
+		d_instantiate(dentry, inode);
+		if (d_unhashed(dentry))
+			d_rehash(dentry);
+	}
+	return new;
+}
+EXPORT_SYMBOL(d_splice_alias);
+
+/**
  * d_materialise_unique - introduce an inode into the tree
  * @dentry: candidate dentry
  * @inode: inode to bind to the dentry, to which aliases may be attached
@@ -2724,7 +2764,7 @@ struct dentry *d_materialise_unique(struct dentry *dentry, struct inode *inode)
 		struct dentry *alias;
 
 		/* Does an aliased dentry already exist? */
-		alias = __d_find_alias(inode, 0);
+		alias = __d_find_alias(inode);
 		if (alias) {
 			actual = alias;
 			write_seqlock(&rename_lock);
diff --git a/fs/direct-io.c b/fs/direct-io.c
index 17e39b047de5..c3116404ab49 100644
--- a/fs/direct-io.c
+++ b/fs/direct-io.c
@@ -158,7 +158,7 @@ static inline int dio_refill_pages(struct dio *dio, struct dio_submit *sdio)
 {
 	ssize_t ret;
 
-	ret = iov_iter_get_pages(sdio->iter, dio->pages, DIO_PAGES * PAGE_SIZE,
+	ret = iov_iter_get_pages(sdio->iter, dio->pages, DIO_PAGES,
 				&sdio->from);
 
 	if (ret < 0 && sdio->blocks_available && (dio->rw & WRITE)) {
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index 3520ab8a6639..b147a67baa0d 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -3455,7 +3455,6 @@ const struct inode_operations ext4_dir_inode_operations = {
 	.rmdir		= ext4_rmdir,
 	.mknod		= ext4_mknod,
 	.tmpfile	= ext4_tmpfile,
-	.rename		= ext4_rename,
 	.rename2	= ext4_rename2,
 	.setattr	= ext4_setattr,
 	.setxattr	= generic_setxattr,
diff --git a/fs/fs_pin.c b/fs/fs_pin.c
new file mode 100644
index 000000000000..9368236ca100
--- /dev/null
+++ b/fs/fs_pin.c
@@ -0,0 +1,78 @@
+#include <linux/fs.h>
+#include <linux/slab.h>
+#include <linux/fs_pin.h>
+#include "internal.h"
+#include "mount.h"
+
+static void pin_free_rcu(struct rcu_head *head)
+{
+	kfree(container_of(head, struct fs_pin, rcu));
+}
+
+static DEFINE_SPINLOCK(pin_lock);
+
+void pin_put(struct fs_pin *p)
+{
+	if (atomic_long_dec_and_test(&p->count))
+		call_rcu(&p->rcu, pin_free_rcu);
+}
+
+void pin_remove(struct fs_pin *pin)
+{
+	spin_lock(&pin_lock);
+	hlist_del(&pin->m_list);
+	hlist_del(&pin->s_list);
+	spin_unlock(&pin_lock);
+}
+
+void pin_insert(struct fs_pin *pin, struct vfsmount *m)
+{
+	spin_lock(&pin_lock);
+	hlist_add_head(&pin->s_list, &m->mnt_sb->s_pins);
+	hlist_add_head(&pin->m_list, &real_mount(m)->mnt_pins);
+	spin_unlock(&pin_lock);
+}
+
+void mnt_pin_kill(struct mount *m)
+{
+	while (1) {
+		struct hlist_node *p;
+		struct fs_pin *pin;
+		rcu_read_lock();
+		p = ACCESS_ONCE(m->mnt_pins.first);
+		if (!p) {
+			rcu_read_unlock();
+			break;
+		}
+		pin = hlist_entry(p, struct fs_pin, m_list);
+		if (!atomic_long_inc_not_zero(&pin->count)) {
+			rcu_read_unlock();
+			cpu_relax();
+			continue;
+		}
+		rcu_read_unlock();
+		pin->kill(pin);
+	}
+}
+
+void sb_pin_kill(struct super_block *sb)
+{
+	while (1) {
+		struct hlist_node *p;
+		struct fs_pin *pin;
+		rcu_read_lock();
+		p = ACCESS_ONCE(sb->s_pins.first);
+		if (!p) {
+			rcu_read_unlock();
+			break;
+		}
+		pin = hlist_entry(p, struct fs_pin, s_list);
+		if (!atomic_long_inc_not_zero(&pin->count)) {
+			rcu_read_unlock();
+			cpu_relax();
+			continue;
+		}
+		rcu_read_unlock();
+		pin->kill(pin);
+	}
+}
diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c
index 0c6048247a34..de1d84af9f7c 100644
--- a/fs/fuse/dir.c
+++ b/fs/fuse/dir.c
@@ -845,12 +845,6 @@ static int fuse_rename2(struct inode *olddir, struct dentry *oldent,
 	return err;
 }
 
-static int fuse_rename(struct inode *olddir, struct dentry *oldent,
-		       struct inode *newdir, struct dentry *newent)
-{
-	return fuse_rename2(olddir, oldent, newdir, newent, 0);
-}
-
 static int fuse_link(struct dentry *entry, struct inode *newdir,
 		     struct dentry *newent)
 {
@@ -2024,7 +2018,6 @@ static const struct inode_operations fuse_dir_inode_operations = {
 	.symlink	= fuse_symlink,
 	.unlink		= fuse_unlink,
 	.rmdir		= fuse_rmdir,
-	.rename		= fuse_rename,
 	.rename2	= fuse_rename2,
 	.link		= fuse_link,
 	.setattr	= fuse_setattr,
diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index 40ac2628ddcf..912061ac4baf 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -1303,10 +1303,10 @@ static int fuse_get_user_pages(struct fuse_req *req, struct iov_iter *ii,
 	while (nbytes < *nbytesp && req->num_pages < req->max_pages) {
 		unsigned npages;
 		size_t start;
-		unsigned n = req->max_pages - req->num_pages;
 		ssize_t ret = iov_iter_get_pages(ii,
 					&req->pages[req->num_pages],
-					n * PAGE_SIZE, &start);
+					req->max_pages - req->num_pages,
+					&start);
 		if (ret < 0)
 			return ret;
 
diff --git a/fs/hostfs/hostfs.h b/fs/hostfs/hostfs.h
index 9c88da0e855a..4fcd40d6f308 100644
--- a/fs/hostfs/hostfs.h
+++ b/fs/hostfs/hostfs.h
@@ -89,6 +89,7 @@ extern int do_mknod(const char *file, int mode, unsigned int major,
 extern int link_file(const char *from, const char *to);
 extern int hostfs_do_readlink(char *file, char *buf, int size);
 extern int rename_file(char *from, char *to);
+extern int rename2_file(char *from, char *to, unsigned int flags);
 extern int do_statfs(char *root, long *bsize_out, long long *blocks_out,
 		     long long *bfree_out, long long *bavail_out,
 		     long long *files_out, long long *ffree_out,
diff --git a/fs/hostfs/hostfs_kern.c b/fs/hostfs/hostfs_kern.c
index bb529f3b7f2b..fd62cae0fdcb 100644
--- a/fs/hostfs/hostfs_kern.c
+++ b/fs/hostfs/hostfs_kern.c
@@ -741,21 +741,31 @@ static int hostfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode,
 	return err;
 }
 
-static int hostfs_rename(struct inode *from_ino, struct dentry *from,
-			 struct inode *to_ino, struct dentry *to)
+static int hostfs_rename2(struct inode *old_dir, struct dentry *old_dentry,
+			  struct inode *new_dir, struct dentry *new_dentry,
+			  unsigned int flags)
 {
-	char *from_name, *to_name;
+	char *old_name, *new_name;
 	int err;
 
-	if ((from_name = dentry_name(from)) == NULL)
+	if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE))