Merge branch 'cross-rename' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs

Pull renameat2 system call from Miklos Szeredi:
 "This adds a new syscall, renameat2(), which is the same as renameat()
  but with a flags argument.

  The purpose of extending rename is to add cross-rename, a symmetric
  variant of rename, which exchanges the two files.  This allows
  interesting things, which were not possible before, for example
  atomically replacing a directory tree with a symlink, etc...  This
  also allows overlayfs and friends to operate on whiteouts atomically.

  Andy Lutomirski also suggested a "noreplace" flag, which disables the
  overwriting behavior of rename.

  These two flags, RENAME_EXCHANGE and RENAME_NOREPLACE are only
  implemented for ext4 as an example and for testing"

* 'cross-rename' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs:
  ext4: add cross rename support
  ext4: rename: split out helper functions
  ext4: rename: move EMLINK check up
  ext4: rename: create ext4_renament structure for local vars
  vfs: add cross-rename
  vfs: lock_two_nondirectories: allow directory args
  security: add flags to rename hooks
  vfs: add RENAME_NOREPLACE flag
  vfs: add renameat2 syscall
  vfs: rename: use common code for dir and non-dir
  vfs: rename: move d_move() up
  vfs: add d_is_dir()

17 files changed, 643 insertions, 313 deletions

diff --git a/Documentation/filesystems/Locking b/Documentation/filesystems/Locking
index 5b0c083d7c0e..f424e0e5b46b 100644
--- a/Documentation/filesystems/Locking
+++ b/Documentation/filesystems/Locking
@@ -47,6 +47,8 @@ prototypes:
         int (*mknod) (struct inode *,struct dentry *,umode_t,dev_t);
         int (*rename) (struct inode *, struct dentry *,
                         struct inode *, struct dentry *);
+        int (*rename2) (struct inode *, struct dentry *,
+                        struct inode *, struct dentry *, unsigned int);
         int (*readlink) (struct dentry *, char __user *,int);
         void * (*follow_link) (struct dentry *, struct nameidata *);
         void (*put_link) (struct dentry *, struct nameidata *, void *);
@@ -78,6 +80,7 @@ mkdir:		yes
 unlink:         yes (both)
 rmdir:          yes (both)      (see below)
 rename:         yes (all)       (see below)
+rename2:        yes (all)       (see below)
 readlink:       no
 follow_link:    no
 put_link:       no
@@ -96,7 +99,8 @@ tmpfile:	no
 
         Additionally, ->rmdir(), ->unlink() and ->rename() have ->i_mutex on
 victim.
-        cross-directory ->rename() has (per-superblock) ->s_vfs_rename_sem.
+        cross-directory ->rename() and rename2() has (per-superblock)
+->s_vfs_rename_sem.
 
 See Documentation/filesystems/directory-locking for more detailed discussion
 of the locking scheme for directory operations.
diff --git a/Documentation/filesystems/vfs.txt b/Documentation/filesystems/vfs.txt
index c53784c119c8..94eb86287bcb 100644
--- a/Documentation/filesystems/vfs.txt
+++ b/Documentation/filesystems/vfs.txt
@@ -347,6 +347,8 @@ struct inode_operations {
         int (*mknod) (struct inode *,struct dentry *,umode_t,dev_t);
         int (*rename) (struct inode *, struct dentry *,
                         struct inode *, struct dentry *);
+        int (*rename2) (struct inode *, struct dentry *,
+                        struct inode *, struct dentry *, unsigned int);
         int (*readlink) (struct dentry *, char __user *,int);
         void * (*follow_link) (struct dentry *, struct nameidata *);
         void (*put_link) (struct dentry *, struct nameidata *, void *);
@@ -414,6 +416,20 @@ otherwise noted.
   rename: called by the rename(2) system call to rename the object to
         have the parent and name given by the second inode and dentry.
 
+  rename2: this has an additional flags argument compared to rename.
+        If no flags are supported by the filesystem then this method
+        need not be implemented.  If some flags are supported then the
+        filesystem must return -EINVAL for any unsupported or unknown
+        flags.  Currently the following flags are implemented:
+        (1) RENAME_NOREPLACE: this flag indicates that if the target
+        of the rename exists the rename should fail with -EEXIST
+        instead of replacing the target.  The VFS already checks for
+        existence, so for local filesystems the RENAME_NOREPLACE
+        implementation is equivalent to plain rename.
+        (2) RENAME_EXCHANGE: exchange source and target.  Both must
+        exist; this is checked by the VFS.  Unlike plain rename,
+        source and target may be of different type.
+
   readlink: called by the readlink(2) system call. Only required if
         you want to support reading symbolic links
 
diff --git a/arch/x86/syscalls/syscall_64.tbl b/arch/x86/syscalls/syscall_64.tbl
index a12bddc7ccea..04376ac3d9ef 100644
--- a/arch/x86/syscalls/syscall_64.tbl
+++ b/arch/x86/syscalls/syscall_64.tbl
@@ -322,6 +322,7 @@
 313     common  finit_module            sys_finit_module
 314     common  sched_setattr           sys_sched_setattr
 315     common  sched_getattr           sys_sched_getattr
+316     common  renameat2               sys_renameat2
 
 #
 # x32-specific system call numbers start at 512 to avoid cache impact
diff --git a/drivers/staging/lustre/lustre/include/linux/lustre_compat25.h b/drivers/staging/lustre/lustre/include/linux/lustre_compat25.h
index eefdb8d061b1..81cc7a0134bb 100644
--- a/drivers/staging/lustre/lustre/include/linux/lustre_compat25.h
+++ b/drivers/staging/lustre/lustre/include/linux/lustre_compat25.h
@@ -105,8 +105,8 @@ static inline void ll_set_fs_pwd(struct fs_struct *fs, struct vfsmount *mnt,
 #define ll_vfs_unlink(inode,entry,mnt)    vfs_unlink(inode,entry)
 #define ll_vfs_mknod(dir,entry,mnt,mode,dev)    vfs_mknod(dir,entry,mode,dev)
 #define ll_security_inode_unlink(dir,entry,mnt) security_inode_unlink(dir,entry)
-#define ll_vfs_rename(old,old_dir,mnt,new,new_dir,mnt1,delegated_inode) \
-                vfs_rename(old,old_dir,new,new_dir,delegated_inode)
+#define ll_vfs_rename(old, old_dir, mnt, new, new_dir, mnt1) \
+                vfs_rename(old, old_dir, new, new_dir, NULL, 0)
 
 #define cfs_bio_io_error(a,b)   bio_io_error((a))
 #define cfs_bio_endio(a,b,c)    bio_endio((a),(c))
diff --git a/drivers/staging/lustre/lustre/lvfs/lvfs_linux.c b/drivers/staging/lustre/lustre/lvfs/lvfs_linux.c
index e44b7a532de7..374a9b78e1d2 100644
--- a/drivers/staging/lustre/lustre/lvfs/lvfs_linux.c
+++ b/drivers/staging/lustre/lustre/lvfs/lvfs_linux.c
@@ -223,7 +223,7 @@ int lustre_rename(struct dentry *dir, struct vfsmount *mnt,
                 GOTO(put_old, err = PTR_ERR(dchild_new));
 
         err = ll_vfs_rename(dir->d_inode, dchild_old, mnt,
-                            dir->d_inode, dchild_new, mnt, NULL);
+                            dir->d_inode, dchild_new, mnt);
 
         dput(dchild_new);
 put_old:
diff --git a/fs/cachefiles/namei.c b/fs/cachefiles/namei.c
index ca65f39dc8dc..6494d9f673aa 100644
--- a/fs/cachefiles/namei.c
+++ b/fs/cachefiles/namei.c
@@ -391,12 +391,12 @@ try_again:
         path.dentry = dir;
         path_to_graveyard.mnt = cache->mnt;
         path_to_graveyard.dentry = cache->graveyard;
-        ret = security_path_rename(&path, rep, &path_to_graveyard, grave);
+        ret = security_path_rename(&path, rep, &path_to_graveyard, grave, 0);
         if (ret < 0) {
                 cachefiles_io_error(cache, "Rename security error %d", ret);
         } else {
                 ret = vfs_rename(dir->d_inode, rep,
-                                 cache->graveyard->d_inode, grave, NULL);
+                                 cache->graveyard->d_inode, grave, NULL, 0);
                 if (ret != 0 && ret != -ENOMEM)
                         cachefiles_io_error(cache,
                                             "Rename failed with error %d", ret);
diff --git a/fs/dcache.c b/fs/dcache.c
index ca02c13a84aa..66cba5a8a346 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -2483,12 +2483,14 @@ static void switch_names(struct dentry *dentry, struct dentry *target)
                         dentry->d_name.name = dentry->d_iname;
                 } else {
                         /*
-                         * Both are internal.  Just copy target to dentry
+                         * Both are internal.
                          */
-                        memcpy(dentry->d_iname, target->d_name.name,
-                                        target->d_name.len + 1);
-                        dentry->d_name.len = target->d_name.len;
-                        return;
+                        unsigned int i;
+                        BUILD_BUG_ON(!IS_ALIGNED(DNAME_INLINE_LEN, sizeof(long)));
+                        for (i = 0; i < DNAME_INLINE_LEN / sizeof(long); i++) {
+                                swap(((long *) &dentry->d_iname)[i],
+                                     ((long *) &target->d_iname)[i]);
+                        }
                 }
         }
         swap(dentry->d_name.len, target->d_name.len);
@@ -2545,13 +2547,15 @@ static void dentry_unlock_parents_for_move(struct dentry *dentry,
  * __d_move - move a dentry
  * @dentry: entry to move
  * @target: new dentry
+ * @exchange: exchange the two dentries
  *
  * Update the dcache to reflect the move of a file name. Negative
  * dcache entries should not be moved in this way. Caller must hold
  * rename_lock, the i_mutex of the source and target directories,
  * and the sb->s_vfs_rename_mutex if they differ. See lock_rename().
  */
-static void __d_move(struct dentry * dentry, struct dentry * target)
+static void __d_move(struct dentry *dentry, struct dentry *target,
+                     bool exchange)
 {
         if (!dentry->d_inode)
                 printk(KERN_WARNING "VFS: moving negative dcache entry\n");
@@ -2573,8 +2577,15 @@ static void __d_move(struct dentry * dentry, struct dentry * target)
         __d_drop(dentry);
         __d_rehash(dentry, d_hash(target->d_parent, target->d_name.hash));
 
-        /* Unhash the target: dput() will then get rid of it */
+        /*
+         * Unhash the target (d_delete() is not usable here).  If exchanging
+         * the two dentries, then rehash onto the other's hash queue.
+         */
         __d_drop(target);
+        if (exchange) {
+                __d_rehash(target,
+                           d_hash(dentry->d_parent, dentry->d_name.hash));
+        }
 
         list_del(&dentry->d_u.d_child);
         list_del(&target->d_u.d_child);
@@ -2601,6 +2612,8 @@ static void __d_move(struct dentry * dentry, struct dentry * target)
         write_seqcount_end(&dentry->d_seq);
 
         dentry_unlock_parents_for_move(dentry, target);
+        if (exchange)
+                fsnotify_d_move(target);
         spin_unlock(&target->d_lock);
         fsnotify_d_move(dentry);
         spin_unlock(&dentry->d_lock);
@@ -2618,11 +2631,30 @@ static void __d_move(struct dentry * dentry, struct dentry * target)
 void d_move(struct dentry *dentry, struct dentry *target)
 {
         write_seqlock(&rename_lock);
-        __d_move(dentry, target);
+        __d_move(dentry, target, false);
         write_sequnlock(&rename_lock);
 }
 EXPORT_SYMBOL(d_move);
 
+/*
+ * d_exchange - exchange two dentries
+ * @dentry1: first dentry
+ * @dentry2: second dentry
+ */
+void d_exchange(struct dentry *dentry1, struct dentry *dentry2)
+{
+        write_seqlock(&rename_lock);
+
+        WARN_ON(!dentry1->d_inode);
+        WARN_ON(!dentry2->d_inode);
+        WARN_ON(IS_ROOT(dentry1));
+        WARN_ON(IS_ROOT(dentry2));
+
+        __d_move(dentry1, dentry2, true);
+
+        write_sequnlock(&rename_lock);
+}
+
 /**
  * d_ancestor - search for an ancestor
  * @p1: ancestor dentry
@@ -2670,7 +2702,7 @@ static struct dentry *__d_unalias(struct inode *inode,
         m2 = &alias->d_parent->d_inode->i_mutex;
 out_unalias:
         if (likely(!d_mountpoint(alias))) {
-                __d_move(alias, dentry);
+                __d_move(alias, dentry, false);
                 ret = alias;
         }
 out_err:
diff --git a/fs/ecryptfs/inode.c b/fs/ecryptfs/inode.c
index b167ca48b8ee..d4a9431ec73c 100644
--- a/fs/ecryptfs/inode.c
+++ b/fs/ecryptfs/inode.c
@@ -641,7 +641,7 @@ ecryptfs_rename(struct inode *old_dir, struct dentry *old_dentry,
         }
         rc = vfs_rename(lower_old_dir_dentry->d_inode, lower_old_dentry,
                         lower_new_dir_dentry->d_inode, lower_new_dentry,
-                        NULL);
+                        NULL, 0);
         if (rc)
                 goto out_lock;
         if (target_inode)
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index d050e043e884..1cb84f78909e 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -3000,6 +3000,154 @@ static struct buffer_head *ext4_get_first_dir_block(handle_t *handle,
         return ext4_get_first_inline_block(inode, parent_de, retval);
 }
 
+struct ext4_renament {
+        struct inode *dir;
+        struct dentry *dentry;
+        struct inode *inode;
+        bool is_dir;
+        int dir_nlink_delta;
+
+        /* entry for "dentry" */
+        struct buffer_head *bh;
+        struct ext4_dir_entry_2 *de;
+        int inlined;
+
+        /* entry for ".." in inode if it's a directory */
+        struct buffer_head *dir_bh;
+        struct ext4_dir_entry_2 *parent_de;
+        int dir_inlined;
+};
+
+static int ext4_rename_dir_prepare(handle_t *handle, struct ext4_renament *ent)
+{
+        int retval;
+
+        ent->dir_bh = ext4_get_first_dir_block(handle, ent->inode,
+                                              &retval, &ent->parent_de,
+                                              &ent->dir_inlined);
+        if (!ent->dir_bh)
+                return retval;
+        if (le32_to_cpu(ent->parent_de->inode) != ent->dir->i_ino)
+                return -EIO;
+        BUFFER_TRACE(ent->dir_bh, "get_write_access");
+        return ext4_journal_get_write_access(handle, ent->dir_bh);
+}
+
+static int ext4_rename_dir_finish(handle_t *handle, struct ext4_renament *ent,
+                                  unsigned dir_ino)
+{
+        int retval;
+
+        ent->parent_de->inode = cpu_to_le32(dir_ino);
+        BUFFER_TRACE(ent->dir_bh, "call ext4_handle_dirty_metadata");
+        if (!ent->dir_inlined) {
+                if (is_dx(ent->inode)) {
+                        retval = ext4_handle_dirty_dx_node(handle,
+                                                           ent->inode,
+                                                           ent->dir_bh);
+                } else {
+                        retval = ext4_handle_dirty_dirent_node(handle,
+                                                               ent->inode,
+                                                               ent->dir_bh);
+                }
+        } else {
+                retval = ext4_mark_inode_dirty(handle, ent->inode);
+        }
+        if (retval) {
+                ext4_std_error(ent->dir->i_sb, retval);
+                return retval;
+        }
+        return 0;
+}
+
+static int ext4_setent(handle_t *handle, struct ext4_renament *ent,
+                       unsigned ino, unsigned file_type)
+{
+        int retval;
+
+        BUFFER_TRACE(ent->bh, "get write access");
+        retval = ext4_journal_get_write_access(handle, ent->bh);
+        if (retval)
+                return retval;
+        ent->de->inode = cpu_to_le32(ino);
+        if (EXT4_HAS_INCOMPAT_FEATURE(ent->dir->i_sb,
+                                      EXT4_FEATURE_INCOMPAT_FILETYPE))
+                ent->de->file_type = file_type;
+        ent->dir->i_version++;
+        ent->dir->i_ctime = ent->dir->i_mtime =
+                ext4_current_time(ent->dir);
+        ext4_mark_inode_dirty(handle, ent->dir);
+        BUFFER_TRACE(ent->bh, "call ext4_handle_dirty_metadata");
+        if (!ent->inlined) {
+                retval = ext4_handle_dirty_dirent_node(handle,
+                                                       ent->dir, ent->bh);
+                if (unlikely(retval)) {
+                        ext4_std_error(ent->dir->i_sb, retval);
+                        return retval;
+                }
+        }
+        brelse(ent->bh);
+        ent->bh = NULL;
+
+        return 0;
+}
+
+static int ext4_find_delete_entry(handle_t *handle, struct inode *dir,
+                                  const struct qstr *d_name)
+{
+        int retval = -ENOENT;
+        struct buffer_head *bh;
+        struct ext4_dir_entry_2 *de;
+
+        bh = ext4_find_entry(dir, d_name, &de, NULL);
+        if (bh) {
+                retval = ext4_delete_entry(handle, dir, de, bh);
+                brelse(bh);
+        }
+        return retval;
+}
+
+static void ext4_rename_delete(handle_t *handle, struct ext4_renament *ent)
+{
+        int retval;
+        /*
+         * ent->de could have moved from under us during htree split, so make
+         * sure that we are deleting the right entry.  We might also be pointing
+         * to a stale entry in the unused part of ent->bh so just checking inum
+         * and the name isn't enough.
+         */
+        if (le32_to_cpu(ent->de->inode) != ent->inode->i_ino ||
+            ent->de->name_len != ent->dentry->d_name.len ||
+            strncmp(ent->de->name, ent->dentry->d_name.name,
+                    ent->de->name_len)) {
+                retval = ext4_find_delete_entry(handle, ent->dir,
+                                                &ent->dentry->d_name);
+        } else {
+                retval = ext4_delete_entry(handle, ent->dir, ent->de, ent->bh);
+                if (retval == -ENOENT) {
+                        retval = ext4_find_delete_entry(handle, ent->dir,
+                                                        &ent->dentry->d_name);
+                }
+        }
+
+        if (retval) {
+                ext4_warning(ent->dir->i_sb,
+                                "Deleting old file (%lu), %d, error=%d",
+                                ent->dir->i_ino, ent->dir->i_nlink, retval);
+        }
+}
+
+static void ext4_update_dir_count(handle_t *handle, struct ext4_renament *ent)
+{
+        if (ent->dir_nlink_delta) {
+                if (ent->dir_nlink_delta == -1)
+                        ext4_dec_count(handle, ent->dir);
+                else
+                        ext4_inc_count(handle, ent->dir);
+                ext4_mark_inode_dirty(handle, ent->dir);
+        }
+}
+
 /*
  * Anybody can rename anything with this: the permission checks are left to the
  * higher-level routines.
@@ -3012,198 +3160,267 @@ static int ext4_rename(struct inode *old_dir, struct dentry *old_dentry,
                        struct inode *new_dir, struct dentry *new_dentry)
 {
         handle_t *handle = NULL;
-        struct inode *old_inode, *new_inode;
-        struct buffer_head *old_bh, *new_bh, *dir_bh;
-        struct ext4_dir_entry_2 *old_de, *new_de;
+        struct ext4_renament old = {
+                .dir = old_dir,
+                .dentry = old_dentry,
+                .inode = old_dentry->d_inode,
+        };
+        struct ext4_renament new = {
+                .dir = new_dir,
+                .dentry = new_dentry,
+                .inode = new_dentry->d_inode,
+        };
         int retval;
-        int inlined = 0, new_inlined = 0;
-        struct ext4_dir_entry_2 *parent_de;
 
-        dquot_initialize(old_dir);
-        dquot_initialize(new_dir);
-
-        old_bh = new_bh = dir_bh = NULL;
+        dquot_initialize(old.dir);
+        dquot_initialize(new.dir);
 
         /* Initialize quotas before so that eventual writes go
          * in separate transaction */
-        if (new_dentry->d_inode)
-                dquot_initialize(new_dentry->d_inode);
+        if (new.inode)
+                dquot_initialize(new.inode);
 
-        old_bh = ext4_find_entry(old_dir, &old_dentry->d_name, &old_de, NULL);
+        old.bh = ext4_find_entry(old.dir, &old.dentry->d_name, &old.de, NULL);
         /*
          *  Check for inode number is _not_ due to possible IO errors.
          *  We might rmdir the source, keep it as pwd of some process
          *  and merrily kill the link to whatever was created under the
          *  same name. Goodbye sticky bit ;-<
          */
-        old_inode = old_dentry->d_inode;
         retval = -ENOENT;
-        if (!old_bh || le32_to_cpu(old_de->inode) != old_inode->i_ino)
+        if (!old.bh || le32_to_cpu(old.de->inode) != old.inode->i_ino)
                 goto end_rename;
 
-        new_inode = new_dentry->d_inode;
-        new_bh = ext4_find_entry(new_dir, &new_dentry->d_name,
-                                 &new_de, &new_inlined);
-        if (new_bh) {
-                if (!new_inode) {
-                        brelse(new_bh);
-                        new_bh = NULL;
+        new.bh = ext4_find_entry(new.dir, &new.dentry->d_name,
+                                 &new.de, &new.inlined);
+        if (new.bh) {
+                if (!new.inode) {
+                        brelse(new.bh);
+                        new.bh = NULL;
                 }
         }
-        if (new_inode && !test_opt(new_dir->i_sb, NO_AUTO_DA_ALLOC))
-                ext4_alloc_da_blocks(old_inode);
+        if (new.inode && !test_opt(new.dir->i_sb, NO_AUTO_DA_ALLOC))
+                ext4_alloc_da_blocks(old.inode);
 
-        handle = ext4_journal_start(old_dir, EXT4_HT_DIR,
-                (2 * EXT4_DATA_TRANS_BLOCKS(old_dir->i_sb) +
+        handle = ext4_journal_start(old.dir, EXT4_HT_DIR,
+                (2 * EXT4_DATA_TRANS_BLOCKS(old.dir->i_sb) +
                  EXT4_INDEX_EXTRA_TRANS_BLOCKS + 2));
         if (IS_ERR(handle))
                 return PTR_ERR(handle);
 
-        if (IS_DIRSYNC(old_dir) || IS_DIRSYNC(new_dir))
+        if (IS_DIRSYNC(old.dir) || IS_DIRSYNC(new.dir))
                 ext4_handle_sync(handle);
 
-        if (S_ISDIR(old_inode->i_mode)) {
-                if (new_inode) {
+        if (S_ISDIR(old.inode->i_mode)) {
+                if (new.inode) {
                         retval = -ENOTEMPTY;
-                        if (!empty_dir(new_inode))
+                        if (!empty_dir(new.inode))
+                                goto end_rename;
+                } else {
+                        retval = -EMLINK;
+                        if (new.dir != old.dir && EXT4_DIR_LINK_MAX(new.dir))
                                 goto end_rename;
                 }
-                retval = -EIO;
-                dir_bh = ext4_get_first_dir_block(handle, old_inode,
-                                                  &retval, &parent_de,
-                                                  &inlined);
-                if (!dir_bh)
-                        goto end_rename;
-                if (le32_to_cpu(parent_de->inode) != old_dir->i_ino)
-                        goto end_rename;
-                retval = -EMLINK;
-                if (!new_inode && new_dir != old_dir &&
-                    EXT4_DIR_LINK_MAX(new_dir))
-                        goto end_rename;
-                BUFFER_TRACE(dir_bh, "get_write_access");
-                retval = ext4_journal_get_write_access(handle, dir_bh);
+                retval = ext4_rename_dir_prepare(handle, &old);
                 if (retval)
                         goto end_rename;
         }
-        if (!new_bh) {
-                retval = ext4_add_entry(handle, new_dentry, old_inode);
+        if (!new.bh) {
+                retval = ext4_add_entry(handle, new.dentry, old.inode);
                 if (retval)
                         goto end_rename;
         } else {
-                BUFFER_TRACE(new_bh, "get write access");
-                retval = ext4_journal_get_write_access(handle, new_bh);
+                retval = ext4_setent(handle, &new,
+                                     old.inode->i_ino, old.de->file_type);
                 if (retval)
                         goto end_rename;
-                new_de->inode = cpu_to_le32(old_inode->i_ino);
-                if (EXT4_HAS_INCOMPAT_FEATURE(new_dir->i_sb,
-                                              EXT4_FEATURE_INCOMPAT_FILETYPE))
-                        new_de->file_type = old_de->file_type;
-                new_dir->i_version++;
-                new_dir->i_ctime = new_dir->i_mtime =
-                                        ext4_current_time(new_dir);
-                ext4_mark_inode_dirty(handle, new_dir);
-                BUFFER_TRACE(new_bh, "call ext4_handle_dirty_metadata");
-                if (!new_inlined) {
-                        retval = ext4_handle_dirty_dirent_node(handle,
-                                                               new_dir, new_bh);
-                        if (unlikely(retval)) {
-                                ext4_std_error(new_dir->i_sb, retval);
-                                goto end_rename;
-                        }
-                }
-                brelse(new_bh);
-                new_bh = NULL;
         }
 
         /*
          * Like most other Unix systems, set the ctime for inodes on a
          * rename.
          */
-        old_inode->i_ctime = ext4_current_time(old_inode);
-        ext4_mark_inode_dirty(handle, old_inode);
+        old.inode->i_ctime = ext4_current_time(old.inode);
+        ext4_mark_inode_dirty(handle, old.inode);
 
         /*
          * ok, that's it
          */
-        if (le32_to_cpu(old_de->inode) != old_inode->i_ino ||
-            old_de->name_len != old_dentry->d_name.len ||
-            strncmp(old_de->name, old_dentry->d_name.name, old_de->name_len) ||
-            (retval = ext4_delete_entry(handle, old_dir,
-                                        old_de, old_bh)) == -ENOENT) {
-                /* old_de could have moved from under us during htree split, so
-                 * make sure that we are deleting the right entry.  We might
-                 * also be pointing to a stale entry in the unused part of
-                 * old_bh so just checking inum and the name isn't enough. */
-                struct buffer_head *old_bh2;
-                struct ext4_dir_entry_2 *old_de2;
-
-                old_bh2 = ext4_find_entry(old_dir, &old_dentry->d_name,
-                                          &old_de2, NULL);
-                if (old_bh2) {
-                        retval = ext4_delete_entry(handle, old_dir,
-                                                   old_de2, old_bh2);
-                        brelse(old_bh2);
-                }
+        ext4_rename_delete(handle, &old);
+
+        if (new.inode) {
+                ext4_dec_count(handle, new.inode);
+                new.inode->i_ctime = ext4_current_time(new.inode);
         }
-        if (retval) {
-                ext4_warning(old_dir->i_sb,
-                                "Deleting old file (%lu), %d, error=%d",
-                                old_dir->i_ino, old_dir->i_nlink, retval);
-        }
-
-        if (new_inode) {
-                ext4_dec_count(handle, new_inode);
-                new_inode->i_ctime = ext4_current_time(new_inode);
-        }
-        old_dir->i_ctime = old_dir->i_mtime = ext4_current_time(old_dir);
-        ext4_update_dx_flag(old_dir);
-        if (dir_bh) {
-                parent_de->inode = cpu_to_le32(new_dir->i_ino);
-                BUFFER_TRACE(dir_bh, "call ext4_handle_dirty_metadata");
-                if (!inlined) {
-                        if (is_dx(old_inode)) {
-                                retval = ext4_handle_dirty_dx_node(handle,
-                                                                   old_inode,
-                                                                   dir_bh);
-                        } else {
-                                retval = ext4_handle_dirty_dirent_node(handle,
-                                                        old_inode, dir_bh);
-                        }
-                } else {
-                        retval = ext4_mark_inode_dirty(handle, old_inode);
-                }
-                if (retval) {
-                        ext4_std_error(old_dir->i_sb, retval);
+        old.dir->i_ctime = old.dir->i_mtime = ext4_current_time(old.dir);
+        ext4_update_dx_flag(old.dir);
+        if (old.dir_bh) {
+                retval = ext4_rename_dir_finish(handle, &old, new.dir->i_ino);
+                if (retval)
                         goto end_rename;
-                }
-                ext4_dec_count(handle, old_dir);
-                if (new_inode) {
+
+                ext4_dec_count(handle, old.dir);
+                if (new.inode) {
                         /* checked empty_dir above, can't have another parent,
                          * ext4_dec_count() won't work for many-linked dirs */
-                        clear_nlink(new_inode);
+                        clear_nlink(new.inode);
                 } else {
-                        ext4_inc_count(handle, new_dir);
-                        ext4_update_dx_flag(new_dir);
-                        ext4_mark_inode_dirty(handle, new_dir);
+                        ext4_inc_count(handle, new.dir);
+                        ext4_update_dx_flag(new.dir);
+                        ext4_mark_inode_dirty(handle, new.dir);
                 }
         }
-        ext4_mark_inode_dirty(handle, old_dir);
-        if (new_inode) {
-                ext4_mark_inode_dirty(handle, new_inode);
-                if (!new_inode->i_nlink)
-                        ext4_orphan_add(handle, new_inode);
+        ext4_mark_inode_dirty(handle, old.dir);
+        if (new.inode) {
+                ext4_mark_inode_dirty(handle, new.inode);
+                if (!new.inode->i_nlink)
+                        ext4_orphan_add(handle, new.inode);
         }
         retval = 0;
 
 end_rename:
-        brelse(dir_bh);
-        brelse(old_bh);
-        brelse(new_bh);
+        brelse(old.dir_bh);
+        brelse(old.bh);
+        brelse(new.bh);
         if (handle)
                 ext4_journal_stop(handle);
         return retval;
 }
 
+static int ext4_cross_rename(struct inode *old_dir, struct dentry *old_dentry,
+                             struct inode *new_dir, struct dentry *new_dentry)
+{
+        handle_t *handle = NULL;
+        struct ext4_renament old = {
+                .dir = old_dir,
+                .dentry = old_dentry,
+                .inode = old_dentry->d_inode,
+        };
+        struct ext4_renament new = {
+                .dir = new_dir,
+                .dentry = new_dentry,
+                .inode = new_dentry->d_inode,
+        };
+        u8 new_file_type;
+        int retval;
+
+        dquot_initialize(old.dir);
+        dquot_initialize(new.dir);
+
+        old.bh = ext4_find_entry(old.dir, &old.dentry->d_name,
+                                 &old.de, &old.inlined);
+        /*
+         *  Check for inode number is _not_ due to possible IO errors.
+         *  We might rmdir the source, keep it as pwd of some process
+         *  and merrily kill the link to whatever was created under the
+         *  same name. Goodbye sticky bit ;-<
+         */
+        retval = -ENOENT;
+        if (!old.bh || le32_to_cpu(old.de->inode) != old.inode->i_ino)
+                goto end_rename;
+
+        new.bh = ext4_find_entry(new.dir, &new.dentry->d_name,
+                                 &new.de, &new.inlined);
+
+        /* RENAME_EXCHANGE case: old *and* new must both exist */
+        if (!new.bh || le32_to_cpu(new.de->inode) != new.inode->i_ino)
+                goto end_rename;
+
+        handle = ext4_journal_start(old.dir, EXT4_HT_DIR,
+                (2 * EXT4_DATA_TRANS_BLOCKS(old.dir->i_sb) +
+                 2 * EXT4_INDEX_EXTRA_TRANS_BLOCKS + 2));
+        if (IS_ERR(handle))
+                return PTR_ERR(handle);
+
+        if (IS_DIRSYNC(old.dir) || IS_DIRSYNC(new.dir))
+                ext4_handle_sync(handle);
+
+        if (S_ISDIR(old.inode->i_mode)) {
+                old.is_dir = true;
+                retval = ext4_rename_dir_prepare(handle, &old);
+                if (retval)
+                        goto end_rename;
+        }
+        if (S_ISDIR(new.inode->i_mode)) {
+                new.is_dir = true;
+                retval = ext4_rename_dir_prepare(handle, &new);
+                if (retval)
+                        goto end_rename;
+        }
+
+        /*
+         * Other than the special case of overwriting a directory, parents'
+         * nlink only needs to be modified if this is a cross directory rename.
+         */
+        if (old.dir != new.dir && old.is_dir != new.is_dir) {
+                old.dir_nlink_delta = old.is_dir ? -1 : 1;
+                new.dir_nlink_delta = -old.dir_nlink_delta;
+                retval = -EMLINK;
+                if ((old.dir_nlink_delta > 0 && EXT4_DIR_LINK_MAX(old.dir)) ||
+                    (new.dir_nlink_delta > 0 && EXT4_DIR_LINK_MAX(new.dir)))
+                        goto end_rename;
+        }
+
+        new_file_type = new.de->file_type;
+        retval = ext4_setent(handle, &new, old.inode->i_ino, old.de->file_type);
+        if (retval)
+                goto end_rename;
+
+        retval = ext4_setent(handle, &old, new.inode->i_ino, new_file_type);
+        if (retval)
+                goto end_rename;
+
+        /*
+         * Like most other Unix systems, set the ctime for inodes on a
+         * rename.
+         */
+        old.inode->i_ctime = ext4_current_time(old.inode);
+        new.inode->i_ctime = ext4_current_time(new.inode);
+        ext4_mark_inode_dirty(handle, old.inode);
+        ext4_mark_inode_dirty(handle, new.inode);
+
+        if (old.dir_bh) {
+                retval = ext4_rename_dir_finish(handle, &old, new.dir->i_ino);
+                if (retval)
+                        goto end_rename;
+        }
+        if (new.dir_bh) {
+                retval = ext4_rename_dir_finish(handle, &new, old.dir->i_ino);
+                if (retval)
+                        goto end_rename;
+        }
+        ext4_update_dir_count(handle, &old);
+        ext4_update_dir_count(handle, &new);
+        retval = 0;
+
+end_rename:
+        brelse(old.dir_bh);
+        brelse(new.dir_bh);
+        brelse(old.bh);
+        brelse(new.bh);
+        if (handle)
+                ext4_journal_stop(handle);
+        return retval;
+}
+
+static int ext4_rename2(struct inode *old_dir, struct dentry *old_dentry,
+                        struct inode *new_dir, struct dentry *new_dentry,
+                        unsigned int flags)
+{
+        if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE))
+                return -EINVAL;
+
+        if (flags & RENAME_EXCHANGE) {
+                return ext4_cross_rename(old_dir, old_dentry,
+                                         new_dir, new_dentry);
+        }
+        /*
+         * Existence checking was done by the VFS, otherwise "RENAME_NOREPLACE"
+         * is equivalent to regular rename.
+         */
+        return ext4_rename(old_dir, old_dentry, new_dir, new_dentry);
+}
+
 /*
  * directories can handle most operations...
  */
@@ -3218,6 +3435,7 @@ const struct inode_operations ext4_dir_inode_operations = {
         .mknod          = ext4_mknod,
         .tmpfile        = ext4_tmpfile,
         .rename         = ext4_rename,
+        .rename2        = ext4_rename2,
         .setattr        = ext4_setattr,
         .setxattr       = generic_setxattr,
         .getxattr       = generic_getxattr,
diff --git a/fs/inode.c b/fs/inode.c
index e6905152c39f..fb59ba7967f1 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -944,24 +944,22 @@ EXPORT_SYMBOL(unlock_new_inode);
 
 /**
  * lock_two_nondirectories - take two i_mutexes on non-directory objects
+ *
+ * Lock any non-NULL argument that is not a directory.
+ * Zero, one or two objects may be locked by this function.
+ *
  * @inode1: first inode to lock
  * @inode2: second inode to lock
  */
 void lock_two_nondirectories(struct inode *inode1, struct inode *inode2)
 {
-        WARN_ON_ONCE(S_ISDIR(inode1->i_mode));
-        if (inode1 == inode2 || !inode2) {
-                mutex_lock(&inode1->i_mutex);
-                return;
-        }
-        WARN_ON_ONCE(S_ISDIR(inode2->i_mode));
-        if (inode1 < inode2) {
+        if (inode1 > inode2)
+                swap(inode1, inode2);
+
+        if (inode1 && !S_ISDIR(inode1->i_mode))
                 mutex_lock(&inode1->i_mutex);
+        if (inode2 && !S_ISDIR(inode2->i_mode) && inode2 != inode1)
                 mutex_lock_nested(&inode2->i_mutex, I_MUTEX_NONDIR2);
-        } else {
-                mutex_lock(&inode2->i_mutex);
-                mutex_lock_nested(&inode1->i_mutex, I_MUTEX_NONDIR2);
-        }
 }
 EXPORT_SYMBOL(lock_two_nondirectories);
 
@@ -972,8 +970,9 @@ EXPORT_SYMBOL(lock_two_nondirectories);
  */
 void unlock_two_nondirectories(struct inode *inode1, struct inode *inode2)
 {
-        mutex_unlock(&inode1->i_mutex);
-        if (inode2 && inode2 != inode1)
+        if (inode1 && !S_ISDIR(inode1->i_mode))
+                mutex_unlock(&inode1->i_mutex);
+        if (inode2 && !S_ISDIR(inode2->i_mode) && inode2 != inode1)
                 mutex_unlock(&inode2->i_mutex);
 }
 EXPORT_SYMBOL(unlock_two_nondirectories);
diff --git a/fs/namei.c b/fs/namei.c
index 4b491b431990..c1178880f23c 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -1796,7 +1796,7 @@ static int link_path_walk(const char *name, struct nameidata *nd)
                         if (err)
                                 return err;
                 }
-                if (!d_is_directory(nd->path.dentry)) {
+                if (!d_can_lookup(nd->path.dentry)) {
                         err = -ENOTDIR; 
                         break;
                 }
@@ -1817,7 +1817,7 @@ static int path_init(int dfd, const char *name, unsigned int flags,
                 struct dentry *root = nd->root.dentry;
                 struct inode *inode = root->d_inode;
                 if (*name) {
-                        if (!d_is_directory(root))
+                        if (!d_can_lookup(root))
                                 return -ENOTDIR;
                         retval = inode_permission(inode, MAY_EXEC);
                         if (retval)
@@ -1873,7 +1873,7 @@ static int path_init(int dfd, const char *name, unsigned int flags,
                 dentry = f.file->f_path.dentry;
 
                 if (*name) {
-                        if (!d_is_directory(dentry)) {
+                        if (!d_can_lookup(dentry)) {
                                 fdput(f);
                                 return -ENOTDIR;
                         }
@@ -1955,7 +1955,7 @@ static int path_lookupat(int dfd, const char *name,
                 err = complete_walk(nd);
 
         if (!err && nd->flags & LOOKUP_DIRECTORY) {
-                if (!d_is_directory(nd->path.dentry)) {
+                if (!d_can_lookup(nd->path.dentry)) {
                         path_put(&nd->path);
                         err = -ENOTDIR;
                 }
@@ -2414,11 +2414,11 @@ static int may_delete(struct inode *dir, struct dentry *victim, bool isdir)
             IS_IMMUTABLE(inode) || IS_SWAPFILE(inode))
                 return -EPERM;
         if (isdir) {
-                if (!d_is_directory(victim) && !d_is_autodir(victim))
+                if (!d_is_dir(victim))
                         return -ENOTDIR;
                 if (IS_ROOT(victim))
                         return -EBUSY;
-        } else if (d_is_directory(victim) || d_is_autodir(victim))
+        } else if (d_is_dir(victim))
                 return -EISDIR;
         if (IS_DEADDIR(dir))
                 return -ENOENT;
@@ -3016,11 +3016,10 @@ finish_open:
         }
         audit_inode(name, nd->path.dentry, 0);
         error = -EISDIR;
-        if ((open_flag & O_CREAT) &&
-            (d_is_directory(nd->path.dentry) || d_is_autodir(nd->path.dentry)))
+        if ((open_flag & O_CREAT) && d_is_dir(nd->path.dentry))
                 goto out;
         error = -ENOTDIR;
-        if ((nd->flags & LOOKUP_DIRECTORY) && !d_is_directory(nd->path.dentry))
+        if ((nd->flags & LOOKUP_DIRECTORY) && !d_can_lookup(nd->path.dentry))
                 goto out;
         if (!S_ISREG(nd->inode->i_mode))
                 will_truncate = false;
@@ -3744,7 +3743,7 @@ exit1:
 slashes:
         if (d_is_negative(dentry))
                 error = -ENOENT;
-        else if (d_is_directory(dentry) || d_is_autodir(dentry))
+        else if (d_is_dir(dentry))
                 error = -EISDIR;
         else
                 error = -ENOTDIR;
@@ -3974,7 +3973,28 @@ SYSCALL_DEFINE2(link, const char __user *, oldname, const char __user *, newname
         return sys_linkat(AT_FDCWD, oldname, AT_FDCWD, newname, 0);
 }
 
-/*
+/**
+ * vfs_rename - rename a filesystem object
+ * @old_dir:    parent of source
+ * @old_dentry: source
+ * @new_dir:    parent of destination
+ * @new_dentry: destination
+ * @delegated_inode: returns an inode needing a delegation break
+ * @flags:      rename flags
+ *
+ * The caller must hold multiple mutexes--see lock_rename()).
+ *
+ * If vfs_rename discovers a delegation in need of breaking at either
+ * the source or destination, it will return -EWOULDBLOCK and return a
+ * reference to the inode in delegated_inode.  The caller should then
+ * break the delegation and retry.  Because breaking a delegation may
+ * take a long time, the caller should drop all locks before doing
+ * so.
+ *
+ * Alternatively, a caller may pass NULL for delegated_inode.  This may
+ * be appropriate for callers that expect the underlying filesystem not
+ * to be NFS exported.
+ *
  * The worst of all namespace operations - renaming directory. "Perverted"
  * doesn't even start to describe it. Somebody in UCB had a heck of a trip...
  * Problems:
@@ -4002,163 +4022,139 @@ SYSCALL_DEFINE2(link, const char __user *, oldname, const char __user *, newname
  *         ->i_mutex on parents, which works but leads to some truly excessive
  *         locking].
  */
-static int vfs_rename_dir(struct inode *old_dir, struct dentry *old_dentry,
-                          struct inode *new_dir, struct dentry *new_dentry)
+int vfs_rename(struct inode *old_dir, struct dentry *old_dentry,
+               struct inode *new_dir, struct dentry *new_dentry,
+               struct inode **delegated_inode, unsigned int flags)
 {
-        int error = 0;
+        int error;
+        bool is_dir = d_is_dir(old_dentry);
+        const unsigned char *old_name;
+        struct inode *source = old_dentry->d_inode;
         struct inode *target = new_dentry->d_inode;
+        bool new_is_dir = false;
         unsigned max_links = new_dir->i_sb->s_max_links;
 
+        if (source == target)
+                return 0;
+
+        error = may_delete(old_dir, old_dentry, is_dir);
+        if (error)
+                return error;
+
+        if (!target) {
+                error = may_create(new_dir, new_dentry);
+        } else {
+                new_is_dir = d_is_dir(new_dentry);
+
+                if (!(flags & RENAME_EXCHANGE))
+                        error = may_delete(new_dir, new_dentry, is_dir);
+                else
+                        error = may_delete(new_dir, new_dentry, new_is_dir);
+        }
+        if (error)
+                return error;
+
+        if (!old_dir->i_op->rename)
+                return -EPERM;
+
+        if (flags && !old_dir->i_op->rename2)
+                return -EINVAL;
+
         /*
          * If we are going to change the parent - check write permissions,
          * we'll need to flip '..'.
          */
         if (new_dir != old_dir) {
-                error = inode_permission(old_dentry->d_inode, MAY_WRITE);
-                if (error)
-                        return error;
+                if (is_dir) {
+                        error = inode_permission(source, MAY_WRITE);
+                        if (error)
+                                return error;
+                }
+                if ((flags & RENAME_EXCHANGE) && new_is_dir) {
+                        error = inode_permission(target, MAY_WRITE);
+                        if (error)
+                                return error;
+                }
         }
 
-        error = security_inode_rename(old_dir, old_dentry, new_dir, new_dentry);
+        error = security_inode_rename(old_dir, old_dentry, new_dir, new_dentry,
+                                      flags);
         if (error)
                 return error;
 
+        old_name = fsnotify_oldname_init(old_dentry->d_name.name);
         dget(new_dentry);
-        if (target)
+        if (!is_dir || (flags & RENAME_EXCHANGE))
+                lock_two_nondirectories(source, target);
+        else if (target)
                 mutex_lock(&target->i_mutex);
 
         error = -EBUSY;
         if (d_mountpoint(old_dentry) || d_mountpoint(new_dentry))
                 goto out;
 
-        error = -EMLINK;
-        if (max_links && !target && new_dir != old_dir &&
-            new_dir->i_nlink >= max_links)
-                goto out;
-
-        if (target)
+        if (max_links && new_dir != old_dir) {
+                error = -EMLINK;
+                if (is_dir && !new_is_dir && new_dir->i_nlink >= max_links)
+                        goto out;
+                if ((flags & RENAME_EXCHANGE) && !is_dir && new_is_dir &&
+                    old_dir->i_nlink >= max_links)
+                        goto out;
+        }
+        if (is_dir && !(flags & RENAME_EXCHANGE) && target)
                 shrink_dcache_parent(new_dentry);
-        error = old_dir->i_op->rename(old_dir, old_dentry, new_dir, new_dentry);
-        if (error)
-                goto out;
-
-        if (target) {
-                target->i_flags |= S_DEAD;
-                dont_mount(new_dentry);
+        if (!is_dir) {
+                error = try_break_deleg(source, delegated_inode);
+                if (error)
+                        goto out;
         }
-out:
-        if (target)
-                mutex_unlock(&target->i_mutex);
-        dput(new_dentry);
-        if (!error)
-                if (!(old_dir->i_sb->s_type->fs_flags & FS_RENAME_DOES_D_MOVE))
-                        d_move(old_dentry,new_dentry);
-        return error;
-}
-
-static int vfs_rename_other(struct inode *old_dir, struct dentry *old_dentry,
-                            struct inode *new_dir, struct dentry *new_dentry,
-                            struct inode **delegated_inode)
-{
-        struct inode *target = new_dentry->d_inode;
-        struct inode *source = old_dentry->d_inode;
-        int error;
-
-        error = security_inode_rename(old_dir, old_dentry, new_dir, new_dentry);
-        if (error)
-                return error;
-
-        dget(new_dentry);
-        lock_two_nondirectories(source, target);
-
-        error = -EBUSY;
-        if (d_mountpoint(old_dentry)||d_mountpoint(new_dentry))
-                goto out;
-
-        error = try_break_deleg(source, delegated_inode);
-        if (error)
-                goto out;
-        if (target) {
+        if (target && !new_is_dir) {
                 error = try_break_deleg(target, delegated_inode);
                 if (error)
                         goto out;
         }
-        error = old_dir->i_op->rename(old_dir, old_dentry, new_dir, new_dentry);
+        if (!flags) {
+                error = old_dir->i_op->rename(old_dir, old_dentry,
+                                              new_dir, new_dentry);
+        } else {
+                error = old_dir->i_op->rename2(old_dir, old_dentry,
+                                               new_dir, new_dentry, flags);
+        }
         if (error)
                 goto out;
 
-        if (target)
+        if (!(flags & RENAME_EXCHANGE) && target) {
+                if (is_dir)
+                        target->i_flags |= S_DEAD;
                 dont_mount(new_dentry);
-        if (!(old_dir->i_sb->s_type->fs_flags & FS_RENAME_DOES_D_MOVE))
-                d_move(old_dentry, new_dentry);
+        }
+        if (!(old_dir->i_sb->s_type->fs_flags & FS_RENAME_DOES_D_MOVE)) {
+                if (!(flags & RENAME_EXCHANGE))
+                        d_move(old_dentry, new_dentry);
+                else
+                        d_exchange(old_dentry, new_dentry);
+        }
 out:
-        unlock_two_nondirectories(source, target);
+        if (!is_dir || (flags & RENAME_EXCHANGE))
+                unlock_two_nondirectories(source, target);
+        else if (target)
+                mutex_unlock(&target->i_mutex);
         dput(new_dentry);
-        return error;
-}
-
-/**
- * vfs_rename - rename a filesystem object
- * @old_dir:    parent of source
- * @old_dentry: source
- * @new_dir:    parent of destination
- * @new_dentry: destination
- * @delegated_inode: returns an inode needing a delegation break
- *
- * The caller must hold multiple mutexes--see lock_rename()).
- *
- * If vfs_rename discovers a delegation in need of breaking at either
- * the source or destination, it will return -EWOULDBLOCK and return a
- * reference to the inode in delegated_inode.  The caller should then
- * break the delegation and retry.  Because breaking a delegation may
- * take a long time, the caller should drop all locks before doing
- * so.
- *
- * Alternatively, a caller may pass NULL for delegated_inode.  This may
- * be appropriate for callers that expect the underlying filesystem not
- * to be NFS exported.
- */
-int vfs_rename(struct inode *old_dir, struct dentry *old_dentry,
-               struct inode *new_dir, struct dentry *new_dentry,
-               struct inode **delegated_inode)
-{
-        int error;
-        int is_dir = d_is_directory(old_dentry) || d_is_autodir(old_dentry);
-        const unsigned char *old_name;
-
-        if (old_dentry->d_inode == new_dentry->d_inode)
-                return 0;
- 
-        error = may_delete(old_dir, old_dentry, is_dir);
-        if (error)
-                return error;
-
-        if (!new_dentry->d_inode)
-                error = may_create(new_dir, new_dentry);
-        else
-                error = may_delete(new_dir, new_dentry, is_dir);
-        if (error)
-                return error;
-
-        if (!old_dir->i_op->rename)
-                return -EPERM;
-
-        old_name = fsnotify_oldname_init(old_dentry->d_name.name);
-
-        if (is_dir)
-                error = vfs_rename_dir(old_dir,old_dentry,new_dir,new_dentry);
-        else
-                error = vfs_rename_other(old_dir,old_dentry,new_dir,new_dentry,delegated_inode);
-        if (!error)
+        if (!error) {
                 fsnotify_move(old_dir, new_dir, old_name, is_dir,
-                              new_dentry->d_inode, old_dentry);
+                              !(flags & RENAME_EXCHANGE) ? target : NULL, old_dentry);
+                if (flags & RENAME_EXCHANGE) {
+                        fsnotify_move(new_dir, old_dir, old_dentry->d_name.name,
+                                      new_is_dir, NULL, new_dentry);
+                }
+        }
         fsnotify_oldname_free(old_name);
 
         return error;
 }
 
-SYSCALL_DEFINE4(renameat, int, olddfd, const char __user *, oldname,
-                int, newdfd, const char __user *, newname)
+SYSCALL_DEFINE5(renameat2, int, olddfd, const char __user *, oldname,
+                int, newdfd, const char __user *, newname, unsigned int, flags)
 {
         struct dentry *old_dir, *new_dir;
         struct dentry *old_dentry, *new_dentry;
@@ -4170,6 +4166,13 @@ SYSCALL_DEFINE4(renameat, int, olddfd, const char __user *, oldname,
         unsigned int lookup_flags = 0;
         bool should_retry = false;
         int error;
+
+        if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE))
+                return -EINVAL;
+
+        if ((flags & RENAME_NOREPLACE) && (flags & RENAME_EXCHANGE))
+                return -EINVAL;
+
 retry:
         from = user_path_parent(olddfd, oldname, &oldnd, lookup_flags);
         if (IS_ERR(from)) {
@@ -4193,6 +4196,8 @@ retry:
                 goto exit2;
 
         new_dir = newnd.path.dentry;
+        if (flags & RENAME_NOREPLACE)
+                error = -EEXIST;
         if (newnd.last_type != LAST_NORM)
                 goto exit2;
 
@@ -4202,7 +4207,8 @@ retry:
 
         oldnd.flags &= ~LOOKUP_PARENT;
         newnd.flags &= ~LOOKUP_PARENT;
-        newnd.flags |= LOOKUP_RENAME_TARGET;
+        if (!(flags & RENAME_EXCHANGE))
+                newnd.flags |= LOOKUP_RENAME_TARGET;
 
 retry_deleg:
         trap = lock_rename(new_dir, old_dir);
@@ -4215,34 +4221,49 @@ retry_deleg:
         error = -ENOENT;
         if (d_is_negative(old_dentry))
                 goto exit4;
+        new_dentry = lookup_hash(&newnd);
+        error = PTR_ERR(new_dentry);
+        if (IS_ERR(new_dentry))
+                goto exit4;
+        error = -EEXIST;
+        if ((flags & RENAME_NOREPLACE) && d_is_positive(new_dentry))
+                goto exit5;
+        if (flags & RENAME_EXCHANGE) {
+                error = -ENOENT;
+                if (d_is_negative(new_dentry))
+                        goto exit5;
+
+                if (!d_is_dir(new_dentry)) {
+                        error = -ENOTDIR;
+                        if (newnd.last.name[newnd.last.len])
+                                goto exit5;
+                }
+        }
         /* unless the source is a directory trailing slashes give -ENOTDIR */
-        if (!d_is_directory(old_dentry) && !d_is_autodir(old_dentry)) {
+        if (!d_is_dir(old_dentry)) {
                 error = -ENOTDIR;
                 if (oldnd.last.name[oldnd.last.len])
-                        goto exit4;
-                if (newnd.last.name[newnd.last.len])
-                        goto exit4;
+                        goto exit5;
+                if (!(flags & RENAME_EXCHANGE) && newnd.last.name[newnd.last.len])
+                        goto exit5;
         }
         /* source should not be ancestor of target */
         error = -EINVAL;
         if (old_dentry == trap)
-                goto exit4;
-        new_dentry = lookup_hash(&newnd);
-        error = PTR_ERR(new_dentry);
-        if (IS_ERR(new_dentry))
-                goto exit4;
+                goto exit5;
         /* target should not be an ancestor of source */
-        error = -ENOTEMPTY;
+        if (!(flags & RENAME_EXCHANGE))
+                error = -ENOTEMPTY;
         if (new_dentry == trap)
                 goto exit5;
 
         error = security_path_rename(&oldnd.path, old_dentry,
-                                     &newnd.path, new_dentry);
+                                     &newnd.path, new_dentry, flags);
         if (error)
                 goto exit5;
         error = vfs_rename(old_dir->d_inode, old_dentry,
-                                   new_dir->d_inode, new_dentry,
-                                   &delegated_inode);
+                           new_dir->d_inode, new_dentry,
+                           &delegated_inode, flags);
 exit5:
         dput(new_dentry);
 exit4:
@@ -4272,9 +4293,15 @@ exit:
         return error;
 }
 
+SYSCALL_DEFINE4(renameat, int, olddfd, const char __user *, oldname,
+                int, newdfd, const char __user *, newname)
+{
+        return sys_renameat2(olddfd, oldname, newdfd, newname, 0);
+}
+
 SYSCALL_DEFINE2(rename, const char __user *, oldname, const char __user *, newname)
 {
-        return sys_renameat(AT_FDCWD, oldname, AT_FDCWD, newname);
+        return sys_renameat2(AT_FDCWD, oldname, AT_FDCWD, newname, 0);
 }
 
 int vfs_readlink(struct dentry *dentry, char __user *buffer, int buflen, const char *link)
diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
index 6d7be3f80356..915808b36df7 100644
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -1694,7 +1694,7 @@ nfsd_rename(struct svc_rqst *rqstp, struct svc_fh *ffhp, char *fname, int flen,
         if (ffhp->fh_export->ex_path.dentry != tfhp->fh_export->ex_path.dentry)
                 goto out_dput_new;
 
-        host_err = vfs_rename(fdir, odentry, tdir, ndentry, NULL);
+        host_err = vfs_rename(fdir, odentry, tdir, ndentry, NULL, 0);
         if (!host_err) {
                 host_err = commit_metadata(tfhp);
                 if (!host_err)
diff --git a/include/linux/dcache.h b/include/linux/dcache.h
index bf72e9ac6de0..3b9bfdb83ba6 100644
--- a/include/linux/dcache.h
+++ b/include/linux/dcache.h
@@ -308,6 +308,7 @@ extern void dentry_update_name_case(struct dentry *, struct qstr *);
 
 /* used for rename() and baskets */
 extern void d_move(struct dentry *, struct dentry *);
+extern void d_exchange(struct dentry *, struct dentry *);
 extern struct dentry *d_ancestor(struct dentry *, struct dentry *);
 
 /* appendix may either be NULL or be used for transname suffixes */
@@ -429,7 +430,7 @@ static inline unsigned __d_entry_type(const struct dentry *dentry)
         return dentry->d_flags & DCACHE_ENTRY_TYPE;
 }
 
-static inline bool d_is_directory(const struct dentry *dentry)
+static inline bool d_can_lookup(const struct dentry *dentry)
 {
         return __d_entry_type(dentry) == DCACHE_DIRECTORY_TYPE;
 }
@@ -439,6 +440,11 @@ static inline bool d_is_autodir(const struct dentry *dentry)
         return __d_entry_type(dentry) == DCACHE_AUTODIR_TYPE;
 }
 
+static inline bool d_is_dir(const struct dentry *dentry)
+{
+        return d_can_lookup(dentry) || d_is_autodir(dentry);
+}
+
 static inline bool d_is_symlink(const struct dentry *dentry)
 {
         return __d_entry_type(dentry) == DCACHE_SYMLINK_TYPE;
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 3ca9420f627e..215cb1b09f47 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1461,7 +1461,7 @@ extern int vfs_symlink(struct inode *, struct dentry *, const char *);
 extern int vfs_link(struct dentry *, struct inode *, struct dentry *, struct inode **);
 extern int vfs_rmdir(struct inode *, struct dentry *);
 extern int vfs_unlink(struct inode *, struct dentry *, struct inode **);
-extern int vfs_rename(struct inode *, struct dentry *, struct inode *, struct dentry *, struct inode **);
+extern int vfs_rename(struct inode *, struct dentry *, struct inode *, struct dentry *, struct inode **, unsigned int);
 
 /*
  * VFS dentry helper functions.
@@ -1572,6 +1572,8 @@ struct inode_operations {
         int (*mknod) (struct inode *,struct dentry *,umode_t,dev_t);
         int (*rename) (struct inode *, struct dentry *,
                         struct inode *, struct dentry *);
+        int (*rename2) (struct inode *, struct dentry *,
+                        struct inode *, struct dentry *, unsigned int);
         int (*setattr) (struct dentry *, struct iattr *);
         int (*getattr) (struct vfsmount *mnt, struct dentry *, struct kstat *);
         int (*setxattr) (struct dentry *, const char *,const void *,size_t,int);
diff --git a/include/linux/security.h b/include/linux/security.h
index 2fc42d191f79..6478ce3252c7 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -1793,7 +1793,8 @@ int security_inode_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
 int security_inode_rmdir(struct inode *dir, struct dentry *dentry);
 int security_inode_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t dev);
 int security_inode_rename(struct inode *old_dir, struct dentry *old_dentry,
-                          struct inode *new_dir, struct dentry *new_dentry);
+                          struct inode *new_dir, struct dentry *new_dentry,
+                          unsigned int flags);
 int security_inode_readlink(struct dentry *dentry);
 int security_inode_follow_link(struct dentry *dentry, struct nameidata *nd);
 int security_inode_permission(struct inode *inode, int mask);
@@ -2161,7 +2162,8 @@ static inline int security_inode_mknod(struct inode *dir,
 static inline int security_inode_rename(struct inode *old_dir,
                                          struct dentry *old_dentry,
                                          struct inode *new_dir,
-                                         struct dentry *new_dentry)
+                                         struct dentry *new_dentry,
+                                         unsigned int flags)
 {
         return 0;
 }
@@ -2955,7 +2957,8 @@ int security_path_symlink(struct path *dir, struct dentry *dentry,
 int security_path_link(struct dentry *old_dentry, struct path *new_dir,
                        struct dentry *new_dentry);
 int security_path_rename(struct path *old_dir, struct dentry *old_dentry,
-                         struct path *new_dir, struct dentry *new_dentry);
+                         struct path *new_dir, struct dentry *new_dentry,
+                         unsigned int flags);
 int security_path_chmod(struct path *path, umode_t mode);
 int security_path_chown(struct path *path, kuid_t uid, kgid_t gid);
 int security_path_chroot(struct path *path);
@@ -3003,7 +3006,8 @@ static inline int security_path_link(struct dentry *old_dentry,
 static inline int security_path_rename(struct path *old_dir,
                                        struct dentry *old_dentry,
                                        struct path *new_dir,
-                                       struct dentry *new_dentry)
+                                       struct dentry *new_dentry,
+                                       unsigned int flags)
 {
         return 0;
 }
diff --git a/include/uapi/linux/fs.h b/include/uapi/linux/fs.h
index 6c28b61bb690..ca1a11bb4443 100644
--- a/include/uapi/linux/fs.h
+++ b/include/uapi/linux/fs.h
@@ -35,6 +35,9 @@
 #define SEEK_HOLE       4       /* seek to the next hole */
 #define SEEK_MAX        SEEK_HOLE
 
+#define RENAME_NOREPLACE        (1 << 0)        /* Don't overwrite target */
+#define RENAME_EXCHANGE         (1 << 1)        /* Exchange source and dest */
+
 struct fstrim_range {
         __u64 start;
         __u64 len;
diff --git a/security/security.c b/security/security.c
index 919cad93ac82..8b774f362a3d 100644
--- a/security/security.c
+++ b/security/security.c
@@ -433,11 +433,20 @@ int security_path_link(struct dentry *old_dentry, struct path *new_dir,
 }
 
 int security_path_rename(struct path *old_dir, struct dentry *old_dentry,
-                         struct path *new_dir, struct dentry *new_dentry)
+                         struct path *new_dir, struct dentry *new_dentry,
+                         unsigned int flags)
 {
         if (unlikely(IS_PRIVATE(old_dentry->d_inode) ||
                      (new_dentry->d_inode && IS_PRIVATE(new_dentry->d_inode))))
                 return 0;
+
+        if (flags & RENAME_EXCHANGE) {
+                int err = security_ops->path_rename(new_dir, new_dentry,
+                                                    old_dir, old_dentry);
+                if (err)
+                        return err;
+        }
+
         return security_ops->path_rename(old_dir, old_dentry, new_dir,
                                          new_dentry);
 }
@@ -524,11 +533,20 @@ int security_inode_mknod(struct inode *dir, struct dentry *dentry, umode_t mode,
 }
 
 int security_inode_rename(struct inode *old_dir, struct dentry *old_dentry,
-                           struct inode *new_dir, struct dentry *new_dentry)
+                           struct inode *new_dir, struct dentry *new_dentry,
+                           unsigned int flags)
 {
         if (unlikely(IS_PRIVATE(old_dentry->d_inode) ||
             (new_dentry->d_inode && IS_PRIVATE(new_dentry->d_inode))))
                 return 0;
+
+        if (flags & RENAME_EXCHANGE) {
+                int err = security_ops->inode_rename(new_dir, new_dentry,
+                                                     old_dir, old_dentry);
+                if (err)
+                        return err;
+        }
+
         return security_ops->inode_rename(old_dir, old_dentry,
                                            new_dir, new_dentry);
 }