From: Erez Zadok <ezk@cs.sunysb.edu>
Date: Tue, 15 Apr 2008 20:20:17 +0000 (-0400)
Subject: Unionfs: implement splice_read/write methods directly
X-Git-Tag: unionfs-2.3.3~14
X-Git-Url: https://git.fsl.cs.sunysb.edu/?a=commitdiff_plain;h=0c9ceaa3ee6cac81d52e11b08f3fdf5cd35bbb75;p=unionfs-2.6.22.y.git

Unionfs: implement splice_read/write methods directly

Must implement splice_read/write directly, using VFS helpers, because we can
no longer rely on generic_file_splice_read/write: they need
address_space_operations implemented, which we no longer have.

Signed-off-by: Erez Zadok <ezk@cs.sunysb.edu>
---

diff --git a/fs/unionfs/file.c b/fs/unionfs/file.c
index ee8dd6f6355..6141efc6ccc 100644
--- a/fs/unionfs/file.c
+++ b/fs/unionfs/file.c
@@ -173,6 +173,66 @@ out:
 	return err;
 }
 
+static ssize_t unionfs_splice_read(struct file *file, loff_t *ppos,
+				   struct pipe_inode_info *pipe, size_t len,
+				   unsigned int flags)
+{
+	ssize_t err;
+	struct file *lower_file;
+	struct dentry *dentry = file->f_path.dentry;
+
+	unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_PARENT);
+	unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
+	err = unionfs_file_revalidate(file, false);
+	if (unlikely(err))
+		goto out;
+
+	lower_file = unionfs_lower_file(file);
+	err = vfs_splice_to(lower_file, ppos, pipe, len, flags);
+	/* update our inode atime upon a successful lower splice-read */
+	if (err >= 0) {
+		fsstack_copy_attr_atime(dentry->d_inode,
+					lower_file->f_path.dentry->d_inode);
+		unionfs_check_file(file);
+	}
+
+out:
+	unionfs_unlock_dentry(dentry);
+	unionfs_read_unlock(dentry->d_sb);
+	return err;
+}
+
+static ssize_t unionfs_splice_write(struct pipe_inode_info *pipe,
+				    struct file *file, loff_t *ppos,
+				    size_t len, unsigned int flags)
+{
+	ssize_t err = 0;
+	struct file *lower_file;
+	struct dentry *dentry = file->f_path.dentry;
+
+	unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_PARENT);
+	unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
+	err = unionfs_file_revalidate(file, true);
+	if (unlikely(err))
+		goto out;
+
+	lower_file = unionfs_lower_file(file);
+	err = vfs_splice_from(pipe, lower_file, ppos, len, flags);
+	/* update our inode times+sizes upon a successful lower write */
+	if (err >= 0) {
+		fsstack_copy_inode_size(dentry->d_inode,
+					lower_file->f_path.dentry->d_inode);
+		fsstack_copy_attr_times(dentry->d_inode,
+					lower_file->f_path.dentry->d_inode);
+		unionfs_check_file(file);
+	}
+
+out:
+	unionfs_unlock_dentry(dentry);
+	unionfs_read_unlock(dentry->d_sb);
+	return err;
+}
+
 struct file_operations unionfs_main_fops = {
 	.llseek		= generic_file_llseek,
 	.read		= do_sync_read,
@@ -188,4 +248,6 @@ struct file_operations unionfs_main_fops = {
 	.fsync		= unionfs_fsync,
 	.fasync		= unionfs_fasync,
 	.sendfile	= generic_file_sendfile,
+	.splice_read	= unionfs_splice_read,
+	.splice_write	= unionfs_splice_write,
 };