The NFS server will need a fallback for filesystems that don't have any
kind of copy acceleration yet, and it should be generally useful to have
an in-kernel copy to avoid lots of switches between kernel and
user space. Users who only want a reflink can pass the COPY_REFLINK
flag to disable the fallback.
Signed-off-by: Anna Schumaker <Anna.Schumaker@xxxxxxxxxx>
---
fs/read_write.c | 16 ++++++++++++----
include/linux/copy.h | 6 ++++++
include/uapi/linux/Kbuild | 1 +
include/uapi/linux/copy.h | 6 ++++++
4 files changed, 25 insertions(+), 4 deletions(-)
create mode 100644 include/linux/copy.h
create mode 100644 include/uapi/linux/copy.h
diff --git a/fs/read_write.c b/fs/read_write.c
index 9dafb7f..bd7e7e2 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -7,6 +7,7 @@
#include <linux/slab.h>
#include <linux/stat.h>
#include <linux/fcntl.h>
+#include <linux/copy.h>
#include <linux/file.h>
#include <linux/uio.h>
#include <linux/fsnotify.h>
@@ -1342,7 +1343,7 @@ ssize_t vfs_copy_file_range(struct file *file_in, loff_t pos_in,
struct inode *inode_out;
ssize_t ret;
- if (flags)
+ if (!((flags == 0) || (flags == COPY_REFLINK)))
return -EINVAL;
/* copy_file_range allows full ssize_t len, ignoring MAX_RW_COUNT */
@@ -1355,7 +1356,7 @@ ssize_t vfs_copy_file_range(struct file *file_in, loff_t pos_in,
if (!(file_in->f_mode & FMODE_READ) ||
!(file_out->f_mode & FMODE_WRITE) ||
(file_out->f_flags & O_APPEND) ||
- !file_out->f_op || !file_out->f_op->copy_file_range)
+ !file_in->f_op)
return -EBADF;
inode_in = file_inode(file_in);
@@ -1377,8 +1378,15 @@ ssize_t vfs_copy_file_range(struct file *file_in, loff_t pos_in,
if (ret)
return ret;
- ret = file_out->f_op->copy_file_range(file_in, pos_in, file_out, pos_out,
- len, flags);
+ ret = -EOPNOTSUPP;
+ if (file_out->f_op->copy_file_range)
+ ret = file_out->f_op->copy_file_range(file_in, pos_in, file_out,
+ pos_out, len, flags);
+ if ((ret < 0) && !(flags & COPY_REFLINK)) {
+ file_start_write(file_out);
+ ret = do_splice_direct(file_in, &pos_in, file_out, &pos_out, len, 0);
+ file_end_write(file_out);
+ }
if (ret > 0) {
fsnotify_access(file_in);
add_rchar(current, ret);
diff --git a/include/linux/copy.h b/include/linux/copy.h
new file mode 100644
index 0000000..fd54543
--- /dev/null
+++ b/include/linux/copy.h
@@ -0,0 +1,6 @@
+#ifndef _LINUX_COPY_H
+#define _LINUX_COPY_H
+
+#include <uapi/linux/copy.h>
+
+#endif /* _LINUX_COPY_H */
diff --git a/include/uapi/linux/Kbuild b/include/uapi/linux/Kbuild
index 1ff9942..b6109f3 100644
--- a/include/uapi/linux/Kbuild
+++ b/include/uapi/linux/Kbuild
@@ -90,6 +90,7 @@ header-y += coda_psdev.h
header-y += coff.h
header-y += connector.h
header-y += const.h
+header-y += copy.h
header-y += cramfs_fs.h
header-y += cuda.h
header-y += cyclades.h
diff --git a/include/uapi/linux/copy.h b/include/uapi/linux/copy.h
new file mode 100644
index 0000000..68f3d65
--- /dev/null
+++ b/include/uapi/linux/copy.h
@@ -0,0 +1,6 @@
+#ifndef _UAPI_LINUX_COPY_H
+#define _UAPI_LINUX_COPY_H
+
+#define COPY_REFLINK 1 /* only perform a reflink */
+
+#endif /* _UAPI_LINUX_COPY_H */
--
2.5.1
--
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