Re: [PATCH 04/11] vfs: add missing checks to copy_file_range

Luis Henriques
2018-12-12T11:31:13Z

Dave Chinner <david@fromorbit.com> writes:

<snip>

> +int generic_copy_file_checks(struct file *file_in, loff_t pos_in,
> + struct file *file_out, loff_t pos_out,
> + size_t *req_count, unsigned int flags)
> +{

<snip>

> + /* Don't allow overlapped copying within the same file. */
> + if (inode_in == inode_out &&
> + pos_out + count > pos_in &&
> + pos_out < pos_in + count)
> + return -EINVAL;

I was wondering if, with the above check, it would make sense to also
have an extra patch changing some filesystems (ceph, nfs and cifs) to
simply return -EOPNOTSUPP (instead of -EINVAL) when inode_in ==
inode_out. Something like the diff below (not tested!).

This caught my attention when I was running the latest generic xfstests
on ceph and realised that I had some new failures due to the recently
added copy_file_range support in fsx by Darrick. The failures were
caused by the usage of the same fd both as source and destination.

Cheers,
--
Luis

diff --git a/fs/ceph/file.c b/fs/ceph/file.c
index 189df668b6a0..c22ac60ec0ba 100644
--- a/fs/ceph/file.c
+++ b/fs/ceph/file.c
@@ -1904,7 +1904,7 @@ static ssize_t ceph_copy_file_range(struct file *src_file, loff_t src_off,
bool do_final_copy = false;

if (src_inode == dst_inode)
- return -EINVAL;
+ return -EOPNOTSUPP;
if (ceph_snap(dst_inode) != CEPH_NOSNAP)
return -EROFS;

diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
index 865706edb307..d4f63eae531e 100644
--- a/fs/cifs/cifsfs.c
+++ b/fs/cifs/cifsfs.c
@@ -1068,7 +1068,7 @@ ssize_t cifs_file_copychunk_range(unsigned int xid,
cifs_dbg(FYI, "copychunk range\n");

if (src_inode == target_inode) {
- rc = -EINVAL;
+ rc = -EOPNOTSUPP;
goto out;
}

diff --git a/fs/nfs/nfs4file.c b/fs/nfs/nfs4file.c
index 46d691ba04bc..910a2abade92 100644
--- a/fs/nfs/nfs4file.c
+++ b/fs/nfs/nfs4file.c
@@ -136,7 +136,7 @@ static ssize_t nfs4_copy_file_range(struct file *file_in, loff_t pos_in,
ssize_t ret;

if (file_inode(file_in) == file_inode(file_out))
- return -EINVAL;
+ return -EOPNOTSUPP;
retry:
ret = nfs42_proc_copy(file_in, pos_in, file_out, pos_out, count);
if (ret == -EAGAIN)