Re: [PATCH 03/11] vfs: no fallback for ->copy_file_range

Anna Schumaker
2018-12-03T18:23:27Z

Hi Dave,

On Mon, 2018-12-03 at 19:34 +1100, Dave Chinner wrote:
> From: Dave Chinner <dchinner@redhat.com>
>
> Now that we have generic_copy_file_range(), remove it as a fallback
> case when offloads fail. This puts the responsibility for executing
> fallbacks on the filesystems that implement ->copy_file_range and
> allows us to add operational validity checks to
> generic_copy_file_range().
>
> Rework vfs_copy_file_range() to call a new do_copy_file_range()
> helper to exceute the copying callout, and move calls to
> generic_file_copy_range() into filesystem methods where they
> currently return failures.
>
> Signed-off-by: Dave Chinner <dchinner@redhat.com>
> ---
> fs/ceph/file.c | 17 ++++++++++++++++-
> fs/cifs/cifsfs.c | 4 ++++
> fs/fuse/file.c | 17 ++++++++++++++++-
> fs/nfs/nfs4file.c | 4 ++++

The NFS bits look okay to me:
Acked-by: Anna Schumaker <Anna.Schumaker@Netapp.com

> fs/overlayfs/file.c | 9 ++++++++-
> fs/read_write.c | 24 +++++++++++++++---------
> 6 files changed, 63 insertions(+), 12 deletions(-)
>
> diff --git a/fs/ceph/file.c b/fs/ceph/file.c
> index 189df668b6a0..cf29f0410dcb 100644
> --- a/fs/ceph/file.c
> +++ b/fs/ceph/file.c
> @@ -1885,7 +1885,7 @@ static int is_file_size_ok(struct inode *src_inode,
> struct inode *dst_inode,
> return 0;
> }
>
> -static ssize_t ceph_copy_file_range(struct file *src_file, loff_t src_off,
> +static ssize_t __ceph_copy_file_range(struct file *src_file, loff_t src_off,
> struct file *dst_file, loff_t dst_off,
> size_t len, unsigned int flags)
> {
> @@ -2096,6 +2096,21 @@ static ssize_t ceph_copy_file_range(struct file
> *src_file, loff_t src_off,
> return ret;
> }
>
> +static ssize_t ceph_copy_file_range(struct file *src_file, loff_t src_off,
> + struct file *dst_file, loff_t dst_off,
> + size_t len, unsigned int flags)
> +{
> + ssize_t ret;
> +
> + ret = __ceph_copy_file_range(src_file, src_off, dst_file, dst_off,
> + len, flags);
> +
> + if (ret == -EOPNOTSUPP)
> + ret = generic_copy_file_range(src_file, src_off, dst_file,
> + dst_off, len, flags);
> + return ret;
> +}
> +
> const struct file_operations ceph_file_fops = {
> .open = ceph_open,
> .release = ceph_release,
> diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
> index 865706edb307..5ef4baec6234 100644
> --- a/fs/cifs/cifsfs.c
> +++ b/fs/cifs/cifsfs.c
> @@ -1141,6 +1141,10 @@ static ssize_t cifs_copy_file_range(struct file
> *src_file, loff_t off,
> rc = cifs_file_copychunk_range(xid, src_file, off, dst_file, destoff,
> len, flags);
> free_xid(xid);
> +
> + if (rc == -EOPNOTSUPP)
> + rc = generic_copy_file_range(src_file, off, dst_file,
> + destoff, len, flags);
> return rc;
> }
>
> diff --git a/fs/fuse/file.c b/fs/fuse/file.c
> index b52f9baaa3e7..b86fb0298739 100644
> --- a/fs/fuse/file.c
> +++ b/fs/fuse/file.c
> @@ -3024,7 +3024,7 @@ static long fuse_file_fallocate(struct file *file, int
> mode, loff_t offset,
> return err;
> }
>
> -static ssize_t fuse_copy_file_range(struct file *file_in, loff_t pos_in,
> +static ssize_t __fuse_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)
> {
> @@ -3100,6 +3100,21 @@ static ssize_t fuse_copy_file_range(struct file
> *file_in, loff_t pos_in,
> return err;
> }
>
> +static ssize_t fuse_copy_file_range(struct file *src_file, loff_t src_off,
> + struct file *dst_file, loff_t dst_off,
> + size_t len, unsigned int flags)
> +{
> + ssize_t ret;
> +
> + ret = __fuse_copy_file_range(src_file, src_off, dst_file, dst_off,
> + len, flags);
> +
> + if (ret == -EOPNOTSUPP)
> + ret = generic_copy_file_range(src_file, src_off, dst_file,
> + dst_off, len, flags);
> + return ret;
> +}
> +
> static const struct file_operations fuse_file_operations = {
> .llseek = fuse_file_llseek,
> .read_iter = fuse_file_read_iter,
> diff --git a/fs/nfs/nfs4file.c b/fs/nfs/nfs4file.c
> index 46d691ba04bc..d7766a6eb0f4 100644
> --- a/fs/nfs/nfs4file.c
> +++ b/fs/nfs/nfs4file.c
> @@ -141,6 +141,10 @@ static ssize_t nfs4_copy_file_range(struct file *file_in,
> loff_t pos_in,
> ret = nfs42_proc_copy(file_in, pos_in, file_out, pos_out, count);
> if (ret == -EAGAIN)
> goto retry;
> +
> + if (ret == -EOPNOTSUPP)
> + ret = generic_copy_file_range(file_in, pos_in, file_out,
> + pos_out, count, flags);
> return ret;
> }
>
> diff --git a/fs/overlayfs/file.c b/fs/overlayfs/file.c
> index 84dd957efa24..68736e5d6a56 100644
> --- a/fs/overlayfs/file.c
> +++ b/fs/overlayfs/file.c
> @@ -486,8 +486,15 @@ 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)
> {
> - return ovl_copyfile(file_in, pos_in, file_out, pos_out, len, flags,
> + ssize_t ret;
> +
> + ret = ovl_copyfile(file_in, pos_in, file_out, pos_out, len, flags,
> OVL_COPY);
> +
> + if (ret == -EOPNOTSUPP)
> + ret = generic_copy_file_range(file_in, pos_in, file_out,
> + pos_out, len, flags);
> + return ret;
> }
>
> static loff_t ovl_remap_file_range(struct file *file_in, loff_t pos_in,
> diff --git a/fs/read_write.c b/fs/read_write.c
> index 50114694c98b..44339b44accc 100644
> --- a/fs/read_write.c
> +++ b/fs/read_write.c
> @@ -1570,6 +1570,18 @@ ssize_t generic_copy_file_range(struct file *file_in,
> loff_t pos_in,
> }
> EXPORT_SYMBOL(generic_copy_file_range);
>
> +static ssize_t do_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_out->f_op->copy_file_range)
> + return file_out->f_op->copy_file_range(file_in, pos_in,
> file_out,
> + pos_out, len, flags);
> +
> + return generic_copy_file_range(file_in, &pos_in, file_out, &pos_out,
> + len, flags);
> +}
> +
> /*
> * 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
> @@ -1634,15 +1646,9 @@ 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)
> - goto done;
> - }
> -
> - ret = generic_copy_file_range(file_in, &pos_in, file_out, &pos_out,
> - len, flags);
> + ret = do_copy_file_range(file_in, pos_in, file_out, pos_out, len,
> + flags);
> + WARN_ON_ONCE(ret == -EOPNOTSUPP);
> done:
> if (ret > 0) {
> fsnotify_access(file_in);