goto out;
}
+static void vfat_exchange_ipos(struct inode *old_inode, struct inode *new_inode,
+ loff_t old_i_pos, loff_t new_i_pos)
+{
+ fat_detach(old_inode);
+ fat_detach(new_inode);
+ fat_attach(old_inode, new_i_pos);
+ fat_attach(new_inode, old_i_pos);
+}
+
+static void vfat_move_nlink(struct inode *src, struct inode *dst)
+{
+ drop_nlink(src);
+ inc_nlink(dst);
+}
+
+static int vfat_rename_exchange(struct inode *old_dir, struct dentry *old_dentry,
+ struct inode *new_dir, struct dentry *new_dentry)
+{
+ struct buffer_head *old_dotdot_bh = NULL, *new_dotdot_bh = NULL;
+ struct msdos_dir_entry *old_dotdot_de = NULL, *new_dotdot_de = NULL;
+ struct inode *old_inode, *new_inode;
+ struct timespec64 ts = current_time(old_dir);
+ loff_t old_i_pos, new_i_pos;
+ int err, corrupt = 0;
+ struct super_block *sb = old_dir->i_sb;
+
+ old_inode = d_inode(old_dentry);
+ new_inode = d_inode(new_dentry);
+
+ /* Acquire super block lock for the operation to be atomic */
+ mutex_lock(&MSDOS_SB(sb)->s_lock);
+
+ /* if directories are not the same, get ".." info to update */
+ if (old_dir != new_dir) {
+ err = vfat_get_dotdot_de(old_inode, &old_dotdot_bh,
+ &old_dotdot_de);
+ if (err)
+ goto out;
+
+ err = vfat_get_dotdot_de(new_inode, &new_dotdot_bh,
+ &new_dotdot_de);
+ if (err)
+ goto out;
+ }
+
+ old_i_pos = MSDOS_I(old_inode)->i_pos;
+ new_i_pos = MSDOS_I(new_inode)->i_pos;
+
+ vfat_exchange_ipos(old_inode, new_inode, old_i_pos, new_i_pos);
+
+ err = vfat_sync_ipos(old_dir, new_inode);
+ if (err)
+ goto error_exchange;
+ err = vfat_sync_ipos(new_dir, old_inode);
+ if (err)
+ goto error_exchange;
+
+ /* update ".." directory entry info */
+ if (old_dotdot_de) {
+ err = vfat_update_dotdot_de(new_dir, old_inode, old_dotdot_bh,
+ old_dotdot_de);
+ if (err)
+ goto error_old_dotdot;
+ }
+ if (new_dotdot_de) {
+ err = vfat_update_dotdot_de(old_dir, new_inode, new_dotdot_bh,
+ new_dotdot_de);
+ if (err)
+ goto error_new_dotdot;
+ }
+
+ /* if cross directory and only one is a directory, adjust nlink */
+ if (!old_dotdot_de != !new_dotdot_de) {
+ if (old_dotdot_de)
+ vfat_move_nlink(old_dir, new_dir);
+ else
+ vfat_move_nlink(new_dir, old_dir);
+ }
+
+ vfat_update_dir_metadata(old_dir, &ts);
+ /* if directories are not the same, update new_dir as well */
+ if (old_dir != new_dir)
+ vfat_update_dir_metadata(new_dir, &ts);
+
+out:
+ brelse(old_dotdot_bh);
+ brelse(new_dotdot_bh);
+ mutex_unlock(&MSDOS_SB(sb)->s_lock);
+
+ return err;
+
+error_new_dotdot:
+ if (new_dotdot_de) {
+ corrupt |= vfat_update_dotdot_de(new_dir, new_inode,
+ new_dotdot_bh, new_dotdot_de);
+ }
+
+error_old_dotdot:
+ if (old_dotdot_de) {
+ corrupt |= vfat_update_dotdot_de(old_dir, old_inode,
+ old_dotdot_bh, old_dotdot_de);
+ }
+
+error_exchange:
+ vfat_exchange_ipos(old_inode, new_inode, new_i_pos, old_i_pos);
+ corrupt |= vfat_sync_ipos(new_dir, new_inode);
+ corrupt |= vfat_sync_ipos(old_dir, old_inode);
+
+ if (corrupt < 0) {
+ fat_fs_error(new_dir->i_sb,
+ "%s: Filesystem corrupted (i_pos %lld, %lld)",
+ __func__, old_i_pos, new_i_pos);
+ }
+ goto out;
+}
+
static int vfat_rename2(struct user_namespace *mnt_userns, struct inode *old_dir,
struct dentry *old_dentry, struct inode *new_dir,
struct dentry *new_dentry, unsigned int flags)
{
- if (flags & ~RENAME_NOREPLACE)
+ if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE))
return -EINVAL;
+ if (flags & RENAME_EXCHANGE) {
+ return vfat_rename_exchange(old_dir, old_dentry,
+ new_dir, new_dentry);
+ }
+
/* VFS already handled RENAME_NOREPLACE, handle it as a normal rename */
return vfat_rename(old_dir, old_dentry, new_dir, new_dentry);
}