Unionfs: add read_iter/write_iter opeations

New AIO API in 3.16.

Signed-off-by: Erez Zadok <ezk@cs.sunysb.edu>
Signed-off-by: Mengyang Li <li.mengyang@stonybrook.edu>

diff --git a/fs/unionfs/file.c b/fs/unionfs/file.c
index 91e95740e28e7324c0e8e15bbfdda8334b7f541d..18b5453bf9c4139fe8a11a40bb3b56dbb40cdf3b 100644 (file)
--- a/fs/unionfs/file.c
+++ b/fs/unionfs/file.c
@@ -168,6 +168,91 @@ out:
        return err;
 }
 
+ssize_t
+unionfs_read_iter(struct kiocb *iocb, struct iov_iter *iter)
+{
+       int err = -EINVAL;
+       struct file *file = iocb->ki_filp, *lower_file = NULL;
+       struct dentry *dentry = file->f_path.dentry;
+       struct dentry *parent;
+
+       unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_PARENT);
+       parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT);
+       unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
+
+       err = unionfs_file_revalidate(file, parent, true);
+       if (unlikely(err))
+               goto out;
+
+       lower_file = unionfs_lower_file(file);
+       if (!lower_file->f_op->read_iter)
+               goto out;
+
+       get_file(lower_file);
+       iocb->ki_filp = lower_file;
+       err = lower_file->f_op->read_iter(iocb, iter);
+       iocb->ki_filp = file;
+       fput(lower_file);
+
+       /* update our inode atime upon a successful lower read */
+       /* XXX: need to update upper inode atime when AIO completes */
+       if (err >= 0) {
+               fsstack_copy_attr_atime(dentry->d_inode,
+                                       file_inode(lower_file));
+               unionfs_check_file(file);
+       }
+
+out:
+       unionfs_unlock_dentry(dentry);
+       unionfs_unlock_parent(dentry, parent);
+       unionfs_read_unlock(dentry->d_sb);
+       return err;
+}
+
+ssize_t
+unionfs_write_iter(struct kiocb *iocb, struct iov_iter *iter)
+{
+       int err = -EINVAL;
+       struct file *file = iocb->ki_filp, *lower_file = NULL;
+       struct dentry *dentry = file->f_path.dentry;
+       struct dentry *parent;
+
+       unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_PARENT);
+       parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT);
+       unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
+
+       err = unionfs_file_revalidate(file, parent, true);
+       if (unlikely(err))
+               goto out;
+
+       lower_file = unionfs_lower_file(file);
+       if (!lower_file->f_op->write_iter)
+               goto out;
+
+       get_file(lower_file);
+       iocb->ki_filp = lower_file;
+       err = lower_file->f_op->write_iter(iocb, iter);
+       iocb->ki_filp = file;
+       fput(lower_file);
+
+       /* update our inode times+sizes upon a successful lower write */
+       /* XXX: need to update upper inode times/sizes when AIO completes */
+       if (err >= 0) {
+               fsstack_copy_inode_size(dentry->d_inode,
+                                       file_inode(lower_file));
+               fsstack_copy_attr_times(dentry->d_inode,
+                                       file_inode(lower_file));
+               UNIONFS_F(file)->wrote_to_file = true; /* for delayed copyup */
+               unionfs_check_file(file);
+       }
+
+out:
+       unionfs_unlock_dentry(dentry);
+       unionfs_unlock_parent(dentry, parent);
+       unionfs_read_unlock(dentry->d_sb);
+       return err;
+}
+
 static int unionfs_file_readdir(struct file *file, struct dir_context *ctx)
 {
        return -ENOTDIR;
@@ -455,6 +540,8 @@ struct file_operations unionfs_main_fops = {
        .write          = unionfs_write,
        .aio_read       = unionfs_aio_read,
        .aio_write      = unionfs_aio_write,
+       .read_iter      = unionfs_read_iter,
+       .write_iter     = unionfs_write_iter,
        .iterate        = unionfs_file_readdir,
        .unlocked_ioctl = unionfs_ioctl,
 #ifdef CONFIG_COMPAT