[PATCH 090/119] xfs: add clone file and clone range vfs functions

Darrick J. Wong
2016-06-17T01:27:38Z

Define two VFS functions which allow userspace to reflink a range of
blocks between two files or to reflink one file's contents to another.
These functions fit the new VFS ioctls that standardize the checking
for the btrfs CLONE and CLONE RANGE ioctls.

v2: Plug into the VFS function pointers instead of handling ioctls
directly.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
---
fs/xfs/libxfs/xfs_fs.h | 11 ++++
fs/xfs/xfs_file.c | 142 ++++++++++++++++++++++++++++++++++++++++++++++++
fs/xfs/xfs_ioctl.c | 2 +
3 files changed, 155 insertions(+)

diff --git a/fs/xfs/libxfs/xfs_fs.h b/fs/xfs/libxfs/xfs_fs.h
index 6f4f2c3..788e006 100644
--- a/fs/xfs/libxfs/xfs_fs.h
+++ b/fs/xfs/libxfs/xfs_fs.h
@@ -533,6 +533,17 @@ typedef struct xfs_swapext
#define XFS_IOC_GOINGDOWN _IOR ('X', 125, __uint32_t)
/* XFS_IOC_GETFSUUID ---------- deprecated 140 */

+/* reflink ioctls; these MUST match the btrfs ioctl definitions */
+/* from struct btrfs_ioctl_clone_range_args */
+struct xfs_clone_args {
+ __s64 src_fd;
+ __u64 src_offset;
+ __u64 src_length;
+ __u64 dest_offset;
+};
+
+#define XFS_IOC_CLONE _IOW (0x94, 9, int)
+#define XFS_IOC_CLONE_RANGE _IOW (0x94, 13, struct xfs_clone_args)

#ifndef HAVE_BBMACROS
/*
diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index b979f01..c2953bd 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -1050,6 +1050,146 @@ out_unlock:
return error;
}

+/*
+ * 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)
+{
+ struct inode *inode_in;
+ struct inode *inode_out;
+ ssize_t ret;
+ loff_t bs;
+ loff_t isize;
+ int same_inode;
+ loff_t blen;
+
+ 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;
+
+ /* 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;
+
+ /* 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_unlock;
+ ret = xfs_file_wait_for_io(inode_out, pos_out, len);
+ if (ret)
+ goto out_unlock;
+
+ ret = xfs_reflink_remap_range(XFS_I(inode_in), pos_in, XFS_I(inode_out),
+ pos_out, len);
+ if (ret < 0)
+ goto out_unlock;
+
+out_unlock:
+ 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);
+ 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);
+}

STATIC int
xfs_file_open(
@@ -1719,6 +1859,8 @@ const struct file_operations xfs_file_operations = {
.release = xfs_file_release,
.fsync = xfs_file_fsync,
.fallocate = xfs_file_fallocate,
+ .copy_file_range = xfs_file_copy_range,
+ .clone_file_range = xfs_file_clone_range,
};

const struct file_operations xfs_dir_file_operations = {
diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
index dbca737..0e06a82 100644
--- a/fs/xfs/xfs_ioctl.c
+++ b/fs/xfs/xfs_ioctl.c
@@ -41,6 +41,7 @@
#include "xfs_trans.h"
#include "xfs_pnfs.h"
#include "xfs_acl.h"
+#include "xfs_reflink.h"

#include <linux/capability.h>
#include <linux/dcache.h>
@@ -49,6 +50,7 @@
#include <linux/pagemap.h>
#include <linux/slab.h>
#include <linux/exportfs.h>
+#include <linux/fsnotify.h>

/*
* xfs_find_handle maps from userspace xfs_fsop_handlereq structure to