+/*
+ * Flush all file writes out to disk.
+ */
+static int
+xfs_file_wait_for_io(
+ struct inode *inode,
+ loff_t offset,
+ size_t len)
+{
+ loff_t rounding;
+ loff_t ioffset;
+ loff_t iendoffset;
+ loff_t bs;
+ int ret;
+
+ bs = inode->i_sb->s_blocksize;
+ inode_dio_wait(inode);
+
+ rounding = max_t(xfs_off_t, bs, PAGE_SIZE);
+ ioffset = round_down(offset, rounding);
+ iendoffset = round_up(offset + len, rounding) - 1;
+ ret = filemap_write_and_wait_range(inode->i_mapping, ioffset,
+ iendoffset);
+ return ret;
+}
+
+/* Hook up to the VFS reflink function */
+STATIC int
+xfs_file_share_range(
+ struct file *file_in,
+ loff_t pos_in,
+ struct file *file_out,
+ loff_t pos_out,
+ u64 len,
+ bool is_dedupe)
+{
+ struct inode *inode_in;
+ struct inode *inode_out;
+ ssize_t ret;
+ loff_t bs;
+ loff_t isize;
+ int same_inode;
+ loff_t blen;
+ unsigned int flags = 0;
+
+ inode_in = file_inode(file_in);
+ inode_out = file_inode(file_out);
+ bs = inode_out->i_sb->s_blocksize;
+
+ /* Don't touch certain kinds of inodes */
+ if (IS_IMMUTABLE(inode_out))
+ return -EPERM;
+ if (IS_SWAPFILE(inode_in) ||
+ IS_SWAPFILE(inode_out))
+ return -ETXTBSY;
+
+ /* Reflink only works within this filesystem. */
+ if (inode_in->i_sb != inode_out->i_sb)
+ return -EXDEV;
+ same_inode = (inode_in->i_ino == inode_out->i_ino);
+
+ /* Don't reflink dirs, pipes, sockets... */
+ if (S_ISDIR(inode_in->i_mode) || S_ISDIR(inode_out->i_mode))
+ return -EISDIR;
+ if (S_ISFIFO(inode_in->i_mode) || S_ISFIFO(inode_out->i_mode))
+ return -EINVAL;
+ if (!S_ISREG(inode_in->i_mode) || !S_ISREG(inode_out->i_mode))
+ return -EINVAL;
+
+ /* Don't share DAX file data for now. */
+ if (IS_DAX(inode_in) || IS_DAX(inode_out))
+ return -EINVAL;
+
+ /* Are we going all the way to the end? */
+ isize = i_size_read(inode_in);
+ if (isize == 0)
+ return 0;
+ if (len == 0)
+ len = isize - pos_in;
+
+ /* Ensure offsets don't wrap and the input is inside i_size */
+ if (pos_in + len < pos_in || pos_out + len < pos_out ||
+ pos_in + len > isize)
+ return -EINVAL;
+
+ /* Don't allow dedupe past EOF in the dest file */
+ if (is_dedupe) {
+ loff_t disize;
+
+ disize = i_size_read(inode_out);
+ if (pos_out >= disize || pos_out + len > disize)
+ return -EINVAL;
+ }
+
+ /* If we're linking to EOF, continue to the block boundary. */
+ if (pos_in + len == isize)
+ blen = ALIGN(isize, bs) - pos_in;
+ else
+ blen = len;
+
+ /* Only reflink if we're aligned to block boundaries */
+ if (!IS_ALIGNED(pos_in, bs) || !IS_ALIGNED(pos_in + blen, bs) ||
+ !IS_ALIGNED(pos_out, bs) || !IS_ALIGNED(pos_out + blen, bs))
+ return -EINVAL;
+
+ /* Don't allow overlapped reflink within the same file */
+ if (same_inode && pos_out + blen > pos_in && pos_out < pos_in + blen)
+ return -EINVAL;
+
+ /* Wait for the completion of any pending IOs on srcfile */
+ ret = xfs_file_wait_for_io(inode_in, pos_in, len);
+ if (ret)
+ goto out;
+ ret = xfs_file_wait_for_io(inode_out, pos_out, len);
+ if (ret)
+ goto out;
+
+ if (is_dedupe)
+ flags |= XFS_REFLINK_DEDUPE;
+ ret = xfs_reflink_remap_range(XFS_I(inode_in), pos_in, XFS_I(inode_out),
+ pos_out, len, flags);
+ if (ret < 0)
+ goto out;
+
+out:
+ return ret;
+}
+
+STATIC ssize_t
+xfs_file_copy_range(
+ struct file *file_in,
+ loff_t pos_in,
+ struct file *file_out,
+ loff_t pos_out,
+ size_t len,
+ unsigned int flags)
+{
+ int error;
+
+ error = xfs_file_share_range(file_in, pos_in, file_out, pos_out,
+ len, false);
+ if (error)
+ return error;
+ return len;
+}
+
+STATIC int
+xfs_file_clone_range(
+ struct file *file_in,
+ loff_t pos_in,
+ struct file *file_out,
+ loff_t pos_out,
+ u64 len)
+{
+ return xfs_file_share_range(file_in, pos_in, file_out, pos_out,
+ len, false);
+}
+
+#define XFS_MAX_DEDUPE_LEN (16 * 1024 * 1024)
+STATIC ssize_t
+xfs_file_dedupe_range(
+ struct file *src_file,
+ u64 loff,
+ u64 len,
+ struct file *dst_file,
+ u64 dst_loff)
+{
+ int error;
+
+ /*
+ * Limit the total length we will dedupe for each operation.
+ * This is intended to bound the total time spent in this
+ * ioctl to something sane.
+ */
+ if (len > XFS_MAX_DEDUPE_LEN)
+ len = XFS_MAX_DEDUPE_LEN;
+
+ error = xfs_file_share_range(src_file, loff, dst_file, dst_loff,
+ len, true);
+ if (error)
+ return error;
+ return len;
+}