nilfs2: fix deadlock issue between chcp and thaw ioctls

[deliverable/linux.git] / fs / nilfs2 / ioctl.c

diff --git a/fs/nilfs2/ioctl.c b/fs/nilfs2/ioctl.c
index 06658caa18bd229ab42e01b876538efaf2c48882..0b6387c67e6ca601d91fe75684fede7826c6f11f 100644 (file)
--- a/fs/nilfs2/ioctl.c
+++ b/fs/nilfs2/ioctl.c
@@ -182,7 +182,7 @@ static int nilfs_ioctl_change_cpmode(struct inode *inode, struct file *filp,
        if (copy_from_user(&cpmode, argp, sizeof(cpmode)))
                goto out;
 
-       down_read(&inode->i_sb->s_umount);
+       mutex_lock(&nilfs->ns_snapshot_mount_mutex);
 
        nilfs_transaction_begin(inode->i_sb, &ti, 0);
        ret = nilfs_cpfile_change_cpmode(
@@ -192,7 +192,7 @@ static int nilfs_ioctl_change_cpmode(struct inode *inode, struct file *filp,
        else
                nilfs_transaction_commit(inode->i_sb); /* never fails */
 
-       up_read(&inode->i_sb->s_umount);
+       mutex_unlock(&nilfs->ns_snapshot_mount_mutex);
 out:
        mnt_drop_write_file(filp);
        return ret;