3 files changed, 26 insertions, 8 deletions

diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index d050e043e884..5f19171b3e1f 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -3204,6 +3204,16 @@ end_rename:
         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)
+                return -EINVAL;
+
+        return ext4_rename(old_dir, old_dentry, new_dir, new_dentry);
+}
+
 /*
  * directories can handle most operations...
  */
@@ -3218,6 +3228,7 @@ 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/namei.c b/fs/namei.c
index ab4e48c4a80a..0e9d186b7f77 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -4142,7 +4142,7 @@ SYSCALL_DEFINE5(renameat2, int, olddfd, const char __user *, oldname,
         bool should_retry = false;
         int error;
 
-        if (flags)
+        if (flags & ~RENAME_NOREPLACE)
                 return -EINVAL;
 
 retry:
@@ -4168,6 +4168,8 @@ retry:
                 goto exit2;
 
         new_dir = newnd.path.dentry;
+        if (flags & RENAME_NOREPLACE)
+                error = -EEXIST;
         if (newnd.last_type != LAST_NORM)
                 goto exit2;
 
@@ -4190,22 +4192,25 @@ 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;
         /* unless the source is a directory trailing slashes give -ENOTDIR */
         if (!d_is_dir(old_dentry)) {
                 error = -ENOTDIR;
                 if (oldnd.last.name[oldnd.last.len])
-                        goto exit4;
+                        goto exit5;
                 if (newnd.last.name[newnd.last.len])
-                        goto exit4;
+                        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 (new_dentry == trap)
diff --git a/include/uapi/linux/fs.h b/include/uapi/linux/fs.h
index 6c28b61bb690..9250f4dd7d96 100644
--- a/include/uapi/linux/fs.h
+++ b/include/uapi/linux/fs.h
@@ -35,6 +35,8 @@
 #define SEEK_HOLE       4       /* seek to the next hole */
 #define SEEK_MAX        SEEK_HOLE
 
+#define RENAME_NOREPLACE        (1 << 0)        /* Don't overwrite target */
+
 struct fstrim_range {
         __u64 start;
         __u64 len;