Introduce cifs_copy_file_range()

The earlier changes to copy range for cifs unintentionally disabled the more
common form of server side copy.

The patch introduces the file_operations helper cifs_copy_file_range()
which is used by the syscall copy_file_range. The new file operations
helper allows us to perform server side copies for SMB2.0 and 2.1
servers as well as SMB 3.0+ servers which do not support the ioctl
FSCTL_DUPLICATE_EXTENTS_TO_FILE.

The new helper uses the ioctl FSCTL_SRV_COPYCHUNK_WRITE to perform
server side copies. The helper is called by vfs_copy_file_range() only
once an attempt to clone the file using the ioctl
FSCTL_DUPLICATE_EXTENTS_TO_FILE has failed.

Signed-off-by: Sachin Prabhu <sprabhu@redhat.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
CC: Stable  <stable@vger.kernel.org>
Signed-off-by: Steve French <smfrench@gmail.com>

1 files changed, 2 insertions, 58 deletions

diff --git a/fs/cifs/ioctl.c b/fs/cifs/ioctl.c
index 9bf0f94fae63..265c45fe4ea5 100644
--- a/fs/cifs/ioctl.c
+++ b/fs/cifs/ioctl.c
@@ -34,63 +34,6 @@
 #include "cifs_ioctl.h"
 #include <linux/btrfs.h>
 
-static int cifs_file_copychunk_range(unsigned int xid, struct file *src_file,
-			  struct file *dst_file)
-{
-	struct inode *src_inode = file_inode(src_file);
-	struct inode *target_inode = file_inode(dst_file);
-	struct cifsFileInfo *smb_file_src;
-	struct cifsFileInfo *smb_file_target;
-	struct cifs_tcon *src_tcon;
-	struct cifs_tcon *target_tcon;
-	int rc;
-
-	cifs_dbg(FYI, "ioctl copychunk range\n");
-
-	if (!src_file->private_data || !dst_file->private_data) {
-		rc = -EBADF;
-		cifs_dbg(VFS, "missing cifsFileInfo on copy range src file\n");
-		goto out;
-	}
-
-	rc = -EXDEV;
-	smb_file_target = dst_file->private_data;
-	smb_file_src = src_file->private_data;
-	src_tcon = tlink_tcon(smb_file_src->tlink);
-	target_tcon = tlink_tcon(smb_file_target->tlink);
-
-	if (src_tcon->ses != target_tcon->ses) {
-		cifs_dbg(VFS, "source and target of copy not on same server\n");
-		goto out;
-	}
-
-	/*
-	 * Note: cifs case is easier than btrfs since server responsible for
-	 * checks for proper open modes and file type and if it wants
-	 * server could even support copy of range where source = target
-	 */
-	lock_two_nondirectories(target_inode, src_inode);
-
-	cifs_dbg(FYI, "about to flush pages\n");
-	/* should we flush first and last page first */
-	truncate_inode_pages(&target_inode->i_data, 0);
-
-	if (target_tcon->ses->server->ops->copychunk_range)
-		rc = target_tcon->ses->server->ops->copychunk_range(xid,
-			smb_file_src, smb_file_target, 0, src_inode->i_size, 0);
-	else
-		rc = -EOPNOTSUPP;
-
-	/* force revalidate of size and timestamps of target file now
-	   that target is updated on the server */
-	CIFS_I(target_inode)->time = 0;
-	/* although unlocking in the reverse order from locking is not
-	   strictly necessary here it is a little cleaner to be consistent */
-	unlock_two_nondirectories(src_inode, target_inode);
-out:
-	return rc;
-}
-
 static long cifs_ioctl_copychunk(unsigned int xid, struct file *dst_file,
 			unsigned long srcfd)
 {
@@ -129,7 +72,8 @@ static long cifs_ioctl_copychunk(unsigned int xid, struct file *dst_file,
 	if (S_ISDIR(src_inode->i_mode))
 		goto out_fput;
 
-	rc = cifs_file_copychunk_range(xid, src_file.file, dst_file);
+	rc = cifs_file_copychunk_range(xid, src_file.file, 0, dst_file, 0,
+					src_inode->i_size, 0);
 
 out_fput:
 	fdput(src_file);