shmem: support RENAME_EXCHANGE
This is really simple in tmpfs since the VFS already takes care of
shuffling the dentries. Just adjust nlink on parent directories and touch
c & mtimes.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Acked-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/mm/shmem.c b/mm/shmem.c
index fe95918..0f01800 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -2048,6 +2048,28 @@
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 = S_ISDIR(old_dentry->d_inode->i_mode);
+ bool new_is_dir = S_ISDIR(new_dentry->d_inode->i_mode);
+
+ 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 =
+ old_dentry->d_inode->i_ctime =
+ new_dentry->d_inode->i_ctime = CURRENT_TIME;
+
+ return 0;
+}
+
/*
* The VFS layer already does all the dentry stuff for rename,
* we just have to decrement the usage count for the target if
@@ -2059,9 +2081,12 @@
struct inode *inode = old_dentry->d_inode;
int they_are_dirs = S_ISDIR(inode->i_mode);
- if (flags & ~(RENAME_NOREPLACE))
+ if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE))
return -EINVAL;
+ if (flags & RENAME_EXCHANGE)
+ return shmem_exchange(old_dir, old_dentry, new_dir, new_dentry);
+
if (!simple_empty(new_dentry))
return -ENOTEMPTY;