libfs: Move shmem_exchange to simple_rename_exchange

Move shmem_exchange and make it available to other callers.

Suggested-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Lorenz Bauer <lmb@cloudflare.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Miklos Szeredi <mszeredi@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christian Brauner <christian.brauner@ubuntu.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/bpf/20211028094724.59043-2-lmb@cloudflare.com

diff --git a/fs/libfs.c b/fs/libfs.c
index 51b4de3..1cf144d 100644 (file)
--- a/fs/libfs.c
+++ b/fs/libfs.c
@@ -448,6 +448,30 @@ int simple_rmdir(struct inode *dir, struct dentry *dentry)
 }
 EXPORT_SYMBOL(simple_rmdir);
 
+int simple_rename_exchange(struct inode *old_dir, struct dentry *old_dentry,
+                          struct inode *new_dir, struct dentry *new_dentry)
+{
+       bool old_is_dir = d_is_dir(old_dentry);
+       bool new_is_dir = d_is_dir(new_dentry);
+
+       if (old_dir != new_dir && old_is_dir != new_is_dir) {
+               if (old_is_dir) {
+                       drop_nlink(old_dir);
+                       inc_nlink(new_dir);
+               } else {
+                       drop_nlink(new_dir);
+                       inc_nlink(old_dir);
+               }
+       }
+       old_dir->i_ctime = old_dir->i_mtime =
+       new_dir->i_ctime = new_dir->i_mtime =
+       d_inode(old_dentry)->i_ctime =
+       d_inode(new_dentry)->i_ctime = current_time(old_dir);
+
+       return 0;
+}
+EXPORT_SYMBOL_GPL(simple_rename_exchange);
+
 int simple_rename(struct user_namespace *mnt_userns, struct inode *old_dir,
                  struct dentry *old_dentry, struct inode *new_dir,
                  struct dentry *new_dentry, unsigned int flags)

diff --git a/include/linux/fs.h b/include/linux/fs.h
index f3cfca5..bc4e97b 100644 (file)
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -3383,6 +3383,8 @@ extern int simple_open(struct inode *inode, struct file *file);
 extern int simple_link(struct dentry *, struct inode *, struct dentry *);
 extern int simple_unlink(struct inode *, struct dentry *);
 extern int simple_rmdir(struct inode *, struct dentry *);
+extern int simple_rename_exchange(struct inode *old_dir, struct dentry *old_dentry,
+                                 struct inode *new_dir, struct dentry *new_dentry);
 extern int simple_rename(struct user_namespace *, struct inode *,
                         struct dentry *, struct inode *, struct dentry *,
                         unsigned int);

diff --git a/mm/shmem.c b/mm/shmem.c
index 17e344e..56616aa 100644 (file)
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -2947,28 +2947,6 @@ static int shmem_rmdir(struct inode *dir, struct dentry *dentry)
        return shmem_unlink(dir, dentry);
 }
 
-static int shmem_exchange(struct inode *old_dir, struct dentry *old_dentry, struct inode *new_dir, struct dentry *new_dentry)
-{
-       bool old_is_dir = d_is_dir(old_dentry);
-       bool new_is_dir = d_is_dir(new_dentry);
-
-       if (old_dir != new_dir && old_is_dir != new_is_dir) {
-               if (old_is_dir) {
-                       drop_nlink(old_dir);
-                       inc_nlink(new_dir);
-               } else {
-                       drop_nlink(new_dir);
-                       inc_nlink(old_dir);
-               }
-       }
-       old_dir->i_ctime = old_dir->i_mtime =
-       new_dir->i_ctime = new_dir->i_mtime =
-       d_inode(old_dentry)->i_ctime =
-       d_inode(new_dentry)->i_ctime = current_time(old_dir);
-
-       return 0;
-}
-
 static int shmem_whiteout(struct user_namespace *mnt_userns,
                          struct inode *old_dir, struct dentry *old_dentry)
 {
@@ -3014,7 +2992,7 @@ static int shmem_rename2(struct user_namespace *mnt_userns,
                return -EINVAL;
 
        if (flags & RENAME_EXCHANGE)
-               return shmem_exchange(old_dir, old_dentry, new_dir, new_dentry);
+               return simple_rename_exchange(old_dir, old_dentry, new_dir, new_dentry);
 
        if (!simple_empty(new_dentry))
                return -ENOTEMPTY;