From: Andy Adamson <andros@xxxxxxxxxx>
Move the high level vfs_copy_file_range entrypoint restriction that limits
copy offloading to files on the same mount and super to
a helper function to be called by copy_file_range methods.
Signed-off-by: Andy Adamson <andros@xxxxxxxxxx>
---
fs/read_write.c | 34 +++++++++++++++++++++++-----------
include/linux/fs.h | 1 +
2 files changed, 24 insertions(+), 11 deletions(-)
diff --git a/fs/read_write.c b/fs/read_write.c
index e564a6b..da28205 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -1330,6 +1330,29 @@ COMPAT_SYSCALL_DEFINE4(sendfile64, int, out_fd, int, in_fd,
#endif
/*
+ * copy_offload_same_fs(). Test for file system copy_file_range methods
+ * that support only copy offloading to files on the same mount point
+ * and super (and not to the same file).
+ */
+ssize_t copy_offload_same_fs(struct file *file_in, struct file *file_out)
+{
+ struct inode *inode_in = file_inode(file_in);
+ struct inode *inode_out = file_inode(file_out);
+
+ /* forbid copy not on the same mount point and super */
+ if (inode_in->i_sb != inode_out->i_sb ||
+ file_in->f_path.mnt != file_out->f_path.mnt)
+ return -EXDEV;
+
+ /* forbid ranges in the same file */
+ if (inode_in == inode_out)
+ return -EINVAL;
+
+ return 0;
+}
+EXPORT_SYMBOL(copy_offload_same_fs);
+
+/*
* copy_file_range() differs from regular file read and write in that it
* specifically allows return partial success. When it does so is up to
* the copy_file_range method.
@@ -1339,7 +1362,6 @@ ssize_t vfs_copy_file_range(struct file *file_in, loff_t pos_in,
size_t len, int flags)
{
struct inode *inode_in;
- struct inode *inode_out;
ssize_t ret;
if (flags)
@@ -1362,22 +1384,12 @@ ssize_t vfs_copy_file_range(struct file *file_in, loff_t pos_in,
return -EINVAL;
inode_in = file_inode(file_in);
- inode_out = file_inode(file_out);
/* make sure 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 > i_size_read(inode_in))
return -EINVAL;
- /* this could be relaxed once a method supports cross-fs copies */
- if (inode_in->i_sb != inode_out->i_sb ||
- file_in->f_path.mnt != file_out->f_path.mnt)
- return -EXDEV;
-
- /* forbid ranges in the same file */
- if (inode_in == inode_out)
- return -EINVAL;
-
ret = mnt_want_write_file(file_out);
if (ret)
return ret;
diff --git a/include/linux/fs.h b/include/linux/fs.h
index c97aed8..1c29f2f 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1685,6 +1685,7 @@ extern ssize_t vfs_readv(struct file *, const struct iovec __user *,
unsigned long, loff_t *);
extern ssize_t vfs_writev(struct file *, const struct iovec __user *,
unsigned long, loff_t *);
+extern ssize_t copy_offload_same_fs(struct file *, struct file *);
extern ssize_t vfs_copy_file_range(struct file *, loff_t , struct file *,
loff_t, size_t, int);
--
1.8.3.1
--
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