From: Olga Kornievskaia <kolga@xxxxxxxxxx>
This patch makes it the responsibility of individual filesystems to
allow or deny cross device copies. Both NFS and CIFS have operations
for cross-server copies, and later patches will implement this feature.
Note that as of this patch, the copy_file_range() function might be passed
superblocks from different filesystem types. -EXDEV should be returned
if cross device copies aren't supported, causing the VFS to fall back
on using do_splice_direct().
Signed-off-by: Olga Kornievskaia <kolga@xxxxxxxxxx>
---
Documentation/filesystems/porting | 7 +++++++
fs/cifs/cifsfs.c | 3 +++
fs/nfs/nfs4file.c | 3 +++
fs/overlayfs/file.c | 3 +++
fs/read_write.c | 9 +++------
5 files changed, 19 insertions(+), 6 deletions(-)
diff --git a/Documentation/filesystems/porting b/Documentation/filesystems/porting
index 7b7b845..897e1e7 100644
--- a/Documentation/filesystems/porting
+++ b/Documentation/filesystems/porting
@@ -622,3 +622,10 @@ in your dentry operations instead.
alloc_file_clone(file, flags, ops) does not affect any caller's references.
On success you get a new struct file sharing the mount/dentry with the
original, on failure - ERR_PTR().
+--
+[mandatory]
+ ->copy_file_range() may now be passed files which belong to two
+ different superblocks of the same file system type or which belong
+ to two different filesystems types all together. As before, the
+ destination's copy_file_range() is the function which is called.
+ If it cannot copy ranges from the source, it should return -EXDEV.
diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
index 7065426..f2d7f4f 100644
--- a/fs/cifs/cifsfs.c
+++ b/fs/cifs/cifsfs.c
@@ -1114,6 +1114,9 @@ static ssize_t cifs_copy_file_range(struct file *src_file, loff_t off,
unsigned int xid = get_xid();
ssize_t rc;
+ if (src_file->f_inode->i_sb != dst_file->f_inode->i_sb)
+ return -EXDEV;
+
rc = cifs_file_copychunk_range(xid, src_file, off, dst_file, destoff,
len, flags);
free_xid(xid);
diff --git a/fs/nfs/nfs4file.c b/fs/nfs/nfs4file.c
index 4288a6e..09df688 100644
--- a/fs/nfs/nfs4file.c
+++ b/fs/nfs/nfs4file.c
@@ -135,6 +135,9 @@ static ssize_t nfs4_copy_file_range(struct file *file_in, loff_t pos_in,
{
ssize_t ret;
+ if (file_in->f_inode->i_sb != file_out->f_inode->i_sb)
+ return -EXDEV;
+
if (file_inode(file_in) == file_inode(file_out))
return -EINVAL;
retry:
diff --git a/fs/overlayfs/file.c b/fs/overlayfs/file.c
index aeaefd2..5282853 100644
--- a/fs/overlayfs/file.c
+++ b/fs/overlayfs/file.c
@@ -483,6 +483,9 @@ static ssize_t ovl_copy_file_range(struct file *file_in, loff_t pos_in,
struct file *file_out, loff_t pos_out,
size_t len, unsigned int flags)
{
+ if (file_in->f_inode->i_sb != file_out->f_inode->i_sb)
+ return -EXDEV;
+
return ovl_copyfile(file_in, pos_in, file_out, pos_out, len, flags,
OVL_COPY);
}
diff --git a/fs/read_write.c b/fs/read_write.c
index 39b4a21..fb4ffca 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -1575,10 +1575,6 @@ ssize_t vfs_copy_file_range(struct file *file_in, loff_t pos_in,
(file_out->f_flags & O_APPEND))
return -EBADF;
- /* this could be relaxed once a method supports cross-fs copies */
- if (inode_in->i_sb != inode_out->i_sb)
- return -EXDEV;
-
if (len == 0)
return 0;
@@ -1588,7 +1584,8 @@ ssize_t vfs_copy_file_range(struct file *file_in, loff_t pos_in,
* Try cloning first, this is supported by more file systems, and
* more efficient if both clone and copy are supported (e.g. NFS).
*/
- if (file_in->f_op->clone_file_range) {
+ if (inode_in->i_sb == inode_out->i_sb &&
+ file_in->f_op->clone_file_range) {
ret = file_in->f_op->clone_file_range(file_in, pos_in,
file_out, pos_out, len);
if (ret == 0) {
@@ -1600,7 +1597,7 @@ ssize_t vfs_copy_file_range(struct file *file_in, loff_t pos_in,
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 != -EOPNOTSUPP)
+ if (ret != -EOPNOTSUPP && ret != -EXDEV)
goto done;
}
--
1.8.3.1
