Re: [PATCH v2 2/8] vfs: no fallback for ->copy_file_range

Darrick J. Wong
2019-05-28T16:10:27Z

On Sun, May 26, 2019 at 09:10:53AM +0300, Amir Goldstein 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

execute ^^^^^^^

> generic_file_copy_range() into filesystem methods where they
> currently return failures.
>
> [Amir] overlayfs is not responsible of executing the fallback.
> It is the responsibility of the underlying filesystem.
>
> Signed-off-by: Dave Chinner <dchinner@redhat.com>
> Signed-off-by: Amir Goldstein <amir73il@gmail.com>

Seems fine to me otherwise...
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>

--D

> ---
> fs/ceph/file.c | 21 ++++++++++++++++++---
> fs/cifs/cifsfs.c | 4 ++++
> fs/fuse/file.c | 21 ++++++++++++++++++---
> fs/nfs/nfs4file.c | 20 +++++++++++++++++---
> fs/read_write.c | 25 ++++++++++++++++---------
> 5 files changed, 73 insertions(+), 18 deletions(-)
>
> diff --git a/fs/ceph/file.c b/fs/ceph/file.c
> index 305daf043eb0..e87f7b2023af 100644
> --- a/fs/ceph/file.c
> +++ b/fs/ceph/file.c
> @@ -1889,9 +1889,9 @@ 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,
> - struct file *dst_file, loff_t dst_off,
> - size_t len, unsigned int flags)
> +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)
> {
> struct inode *src_inode = file_inode(src_file);
> struct inode *dst_inode = file_inode(dst_file);
> @@ -2100,6 +2100,21 @@ 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 f5fcd6360056..c65823270313 100644
> --- a/fs/cifs/cifsfs.c
> +++ b/fs/cifs/cifsfs.c
> @@ -1148,6 +1148,10 @@ 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 3959f08279e6..e03901ae729b 100644
> --- a/fs/fuse/file.c
> +++ b/fs/fuse/file.c
> @@ -3097,9 +3097,9 @@ 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,
> - struct file *file_out, loff_t pos_out,
> - size_t len, unsigned int flags)
> +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)
> {
> struct fuse_file *ff_in = file_in->private_data;
> struct fuse_file *ff_out = file_out->private_data;
> @@ -3173,6 +3173,21 @@ 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 cf42a8b939e3..4842f3ab3161 100644
> --- a/fs/nfs/nfs4file.c
> +++ b/fs/nfs/nfs4file.c
> @@ -129,9 +129,9 @@ nfs4_file_flush(struct file *file, fl_owner_t id)
> }
>
> #ifdef CONFIG_NFS_V4_2
> -static ssize_t nfs4_copy_file_range(struct file *file_in, loff_t pos_in,
> - struct file *file_out, loff_t pos_out,
> - size_t count, unsigned int flags)
> +static ssize_t __nfs4_copy_file_range(struct file *file_in, loff_t pos_in,
> + struct file *file_out, loff_t pos_out,
> + size_t count, unsigned int flags)
> {
> if (!nfs_server_capable(file_inode(file_out), NFS_CAP_COPY))
> return -EOPNOTSUPP;
> @@ -140,6 +140,20 @@ static ssize_t nfs4_copy_file_range(struct file *file_in, loff_t pos_in,
> return nfs42_proc_copy(file_in, pos_in, file_out, pos_out, count);
> }
>
> +static ssize_t nfs4_copy_file_range(struct file *file_in, loff_t pos_in,
> + struct file *file_out, loff_t pos_out,
> + size_t count, unsigned int flags)
> +{
> + ssize_t ret;
> +
> + ret = __nfs4_copy_file_range(file_in, pos_in, file_out, pos_out, count,
> + flags);
> + if (ret == -EOPNOTSUPP)
> + ret = generic_copy_file_range(file_in, pos_in, file_out,
> + pos_out, count, flags);
> + return ret;
> +}
> +
> static loff_t nfs4_file_llseek(struct file *filep, loff_t offset, int whence)
> {
> loff_t ret;
> diff --git a/fs/read_write.c b/fs/read_write.c
> index 676b02fae589..b63dcb4e4fe9 100644
> --- a/fs/read_write.c
> +++ b/fs/read_write.c
> @@ -1595,6 +1595,19 @@ 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
> @@ -1655,15 +1668,9 @@ 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);
> --
> 2.17.1
>