ocfs2: implement the VFS clone_range, copy_range, and dedupe_range features

Connect the new VFS clone_range, copy_range, and dedupe_range features
to the existing reflink capability of ocfs2.  Compared to the existing
ocfs2 reflink ioctl We have to do things a little differently to support
the VFS semantics (we can clone subranges of a file but we don't clone
xattrs), but the VFS ioctls are more broadly supported.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
---
v2: Convert inline data files to extents files before reflinking,
and fix i_blocks so that stat(2) output is correct.
v3: Make zero-length dedupe consistent with btrfs behavior.
v4: Use VFS double-inode lock routines and remove MAX_DEDUPE_LEN.

fs/ocfs2/file.c

@@ -1667,7 +1667,7 @@ static void ocfs2_calc_trunc_pos(struct inode *inode,
 	*done = ret;
 }
 
-static int ocfs2_remove_inode_range(struct inode *inode,
+int ocfs2_remove_inode_range(struct inode *inode,
 			     struct buffer_head *di_bh, u64 byte_start,
 			     u64 byte_len)
 {
@@ -2439,6 +2439,31 @@ static loff_t ocfs2_file_llseek(struct file *file, loff_t offset, int whence)
 	return offset;
 }
 
+static int ocfs2_file_clone_range(struct file *file_in,
+				  loff_t pos_in,
+				  struct file *file_out,
+				  loff_t pos_out,
+				  u64 len)
+{
+	return ocfs2_reflink_remap_range(file_in, pos_in, file_out, pos_out,
+					 len, false);
+}
+
+static ssize_t ocfs2_file_dedupe_range(struct file *src_file,
+				       u64 loff,
+				       u64 len,
+				       struct file *dst_file,
+				       u64 dst_loff)
+{
+	int error;
+
+	error = ocfs2_reflink_remap_range(src_file, loff, dst_file, dst_loff,
+					  len, true);
+	if (error)
+		return error;
+	return len;
+}
+
 const struct inode_operations ocfs2_file_iops = {
 	.setattr	= ocfs2_setattr,
 	.getattr	= ocfs2_getattr,
@@ -2478,6 +2503,8 @@ const struct file_operations ocfs2_fops = {
 	.splice_read	= generic_file_splice_read,
 	.splice_write	= iter_file_splice_write,
 	.fallocate	= ocfs2_fallocate,
+	.clone_file_range = ocfs2_file_clone_range,
+	.dedupe_file_range = ocfs2_file_dedupe_range,
 };
 
 const struct file_operations ocfs2_dops = {
@@ -2523,6 +2550,8 @@ const struct file_operations ocfs2_fops_no_plocks = {
 	.splice_read	= generic_file_splice_read,
 	.splice_write	= iter_file_splice_write,
 	.fallocate	= ocfs2_fallocate,
+	.clone_file_range = ocfs2_file_clone_range,
+	.dedupe_file_range = ocfs2_file_dedupe_range,
 };
 
 const struct file_operations ocfs2_dops_no_plocks = {

fs/ocfs2/file.h

@@ -82,4 +82,7 @@ int ocfs2_change_file_space(struct file *file, unsigned int cmd,
 
 int ocfs2_check_range_for_refcount(struct inode *inode, loff_t pos,
 				   size_t count);
+int ocfs2_remove_inode_range(struct inode *inode,
+			     struct buffer_head *di_bh, u64 byte_start,
+			     u64 byte_len);
 #endif /* OCFS2_FILE_H */

fs/ocfs2/refcounttree.h

@@ -115,4 +115,11 @@ int ocfs2_reflink_ioctl(struct inode *inode,
 			const char __user *oldname,
 			const char __user *newname,
 			bool preserve);
+int ocfs2_reflink_remap_range(struct file *file_in,
+			      loff_t pos_in,
+			      struct file *file_out,
+			      loff_t pos_out,
+			      u64 len,
+			      bool is_dedupe);
+
 #endif /* OCFS2_REFCOUNTTREE_H */