Now that a few file systems are adding clone functionality, namingly
btrfs, NFS (later in the series) and XFS
(ttp://oss.sgi.com/archives/xfs/2015-06/msg00407.html), it makes sense
to pull the ioctl to common code.
Add vfs_file_clone_range() helper and .clone_range file operation interface
to allow underlying filesystems to clone between regular files.
The change in do_vfs_ioctl() is defered to next patch where btrfs
.clone_range is added, just so that we don't break btrfs CLONE ioctl
with this patch.
Cc: linux-btrfs@xxxxxxxxxxxxxxx
Cc: linux-fsdevel@xxxxxxxxxxxxxxx
Signed-off-by: Peng Tao <tao.peng@xxxxxxxxxxxxxxx>
---
fs/ioctl.c | 24 ++++++++++++++++++++++++
fs/read_write.c | 45 +++++++++++++++++++++++++++++++++++++++++++++
include/linux/fs.h | 4 ++++
include/uapi/linux/fs.h | 9 +++++++++
4 files changed, 82 insertions(+)
diff --git a/fs/ioctl.c b/fs/ioctl.c
index 5d01d26..726c5d7 100644
--- a/fs/ioctl.c
+++ b/fs/ioctl.c
@@ -215,6 +215,30 @@ static int ioctl_fiemap(struct file *filp, unsigned long arg)
return error;
}
+static long ioctl_file_clone(struct file *dst_file, unsigned long srcfd,
+ u64 off, u64 olen, u64 destoff)
+{
+ struct fd src_file = fdget(srcfd);
+ int ret;
+
+ if (!src_file.file)
+ return -EBADF;
+ ret = vfs_file_clone_range(src_file.file, dst_file, off, olen, destoff);
+
+ fdput(src_file);
+ return ret;
+}
+
+static long ioctl_file_clone_range(struct file *file, void __user *argp)
+{
+ struct file_clone_range args;
+
+ if (copy_from_user(&args, argp, sizeof(args)))
+ return -EFAULT;
+ return ioctl_file_clone(file, args.src_fd, args.src_offset,
+ args.src_length, args.dest_offset);
+}
+
#ifdef CONFIG_BLOCK
static inline sector_t logical_to_blk(struct inode *inode, loff_t offset)
diff --git a/fs/read_write.c b/fs/read_write.c
index 819ef3f..beaad2c 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -16,6 +16,7 @@
#include <linux/pagemap.h>
#include <linux/splice.h>
#include <linux/compat.h>
+#include <linux/mount.h>
#include "internal.h"
#include <asm/uaccess.h>
@@ -1327,3 +1328,47 @@ COMPAT_SYSCALL_DEFINE4(sendfile64, int, out_fd, int, in_fd,
return do_sendfile(out_fd, in_fd, NULL, count, 0);
}
#endif
+
+int vfs_file_clone_range(struct file *src_file, struct file *dst_file,
+ loff_t off, size_t len, loff_t dstoff)
+{
+ struct inode *src_ino;
+ struct inode *dst_ino;
+ ssize_t ret;
+
+ if (!(src_file->f_mode & FMODE_READ) ||
+ !(dst_file->f_mode & FMODE_WRITE) ||
+ (dst_file->f_flags & O_APPEND) ||
+ !src_file->f_op || !src_file->f_op->clone_range)
+ return -EINVAL;
+
+ src_ino = file_inode(src_file);
+ dst_ino = file_inode(dst_file);
+
+ if (S_ISDIR(src_ino->i_mode) || S_ISDIR(dst_ino->i_mode))
+ return -EISDIR;
+
+ /* sanity check on offsets and length */
+ if (off + len < off || dstoff + len < dstoff ||
+ off + len > i_size_read(src_ino))
+ return -EINVAL;
+
+ if (src_ino->i_sb != dst_ino->i_sb ||
+ src_file->f_path.mnt != dst_file->f_path.mnt)
+ return -EXDEV;
+
+ ret = mnt_want_write_file(dst_file);
+ if (ret)
+ return ret;
+
+ ret = src_file->f_op->clone_range(src_file, dst_file, off, len, dstoff);
+ if (!ret) {
+ fsnotify_access(src_file);
+ fsnotify_modify(dst_file);
+ }
+
+ mnt_drop_write_file(dst_file);
+
+ return ret;
+}
+EXPORT_SYMBOL(vfs_file_clone_range);
diff --git a/include/linux/fs.h b/include/linux/fs.h
index cc008c3..612d7f4 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1628,6 +1628,8 @@ struct file_operations {
long (*fallocate)(struct file *file, int mode, loff_t offset,
loff_t len);
void (*show_fdinfo)(struct seq_file *m, struct file *f);
+ int (*clone_range)(struct file *src_file, struct file *dst_file,
+ loff_t off, size_t len, loff_t dstoff);
#ifndef CONFIG_MMU
unsigned (*mmap_capabilities)(struct file *);
#endif
@@ -2678,6 +2680,8 @@ int __dax_fault(struct vm_area_struct *, struct vm_fault *, get_block_t,
int dax_pfn_mkwrite(struct vm_area_struct *, struct vm_fault *);
#define dax_mkwrite(vma, vmf, gb, iod) dax_fault(vma, vmf, gb, iod)
#define __dax_mkwrite(vma, vmf, gb, iod) __dax_fault(vma, vmf, gb, iod)
+int vfs_file_clone_range(struct file *src_file, struct file *dst_file,
+ loff_t off, size_t len, loff_t dstoff);
#ifdef CONFIG_BLOCK
typedef void (dio_submit_t)(int rw, struct bio *bio, struct inode *inode,
diff --git a/include/uapi/linux/fs.h b/include/uapi/linux/fs.h
index 9b964a5..ac7f1c5 100644
--- a/include/uapi/linux/fs.h
+++ b/include/uapi/linux/fs.h
@@ -39,6 +39,13 @@
#define RENAME_EXCHANGE (1 << 1) /* Exchange source and dest */
#define RENAME_WHITEOUT (1 << 2) /* Whiteout source */
+struct file_clone_range {
+ __s64 src_fd;
+ __u64 src_offset;
+ __u64 src_length;
+ __u64 dest_offset;
+};
+
struct fstrim_range {
__u64 start;
__u64 len;
@@ -159,6 +166,8 @@ struct inodes_stat_t {
#define FIFREEZE _IOWR('X', 119, int) /* Freeze */
#define FITHAW _IOWR('X', 120, int) /* Thaw */
#define FITRIM _IOWR('X', 121, struct fstrim_range) /* Trim */
+#define FICLONE _IOW(0x94, 9, int) /* Clone */
+#define FICLONERANGE _IOW(0x94, 13, struct file_clone_range) /* Clone range */
#define FS_IOC_GETFLAGS _IOR('f', 1, long)
#define FS_IOC_SETFLAGS _IOW('f', 2, long)
--
1.8.3.1
--
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