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SubjectRe: [PATCH v2 21/35] ovl: add reflink/copyfile/dedup support
On Mon, May 07, 2018 at 10:37:53AM +0200, Miklos Szeredi wrote:
> Since set of arguments are so similar, handle in a common helper.
>
> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
> ---
> fs/overlayfs/file.c | 88 +++++++++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 88 insertions(+)
>
> diff --git a/fs/overlayfs/file.c b/fs/overlayfs/file.c
> index ce871a15e185..2ac95c95e8e6 100644
> --- a/fs/overlayfs/file.c
> +++ b/fs/overlayfs/file.c
> @@ -382,6 +382,90 @@ static long ovl_compat_ioctl(struct file *file, unsigned int cmd,
> return ovl_ioctl(file, cmd, arg);
> }
>
> +enum ovl_copyop {
> + OVL_COPY,
> + OVL_CLONE,
> + OVL_DEDUPE,
> +};
> +
> +static s64 ovl_copyfile(struct file *file_in, loff_t pos_in,
> + struct file *file_out, loff_t pos_out,
> + u64 len, unsigned int flags, enum ovl_copyop op)
> +{
> + struct inode *inode_out = file_inode(file_out);
> + struct fd real_in, real_out;
> + const struct cred *old_cred;
> + s64 ret;
> +
> + ret = ovl_real_fdget(file_out, &real_out);
> + if (ret)
> + return ret;
> +
> + ret = ovl_real_fdget(file_in, &real_in);
> + if (ret) {
> + fdput(real_out);
> + return ret;
> + }
> +
> + old_cred = ovl_override_creds(file_inode(file_out)->i_sb);
> + switch (op) {
> + case OVL_COPY:
> + ret = vfs_copy_file_range(real_in.file, pos_in,
> + real_out.file, pos_out, len, flags);
> + break;
> +
> + case OVL_CLONE:
> + ret = vfs_clone_file_range(real_in.file, pos_in,
> + real_out.file, pos_out, len);
> + break;
> +
> + case OVL_DEDUPE:
> + ret = vfs_dedupe_file_range_one(real_in.file, pos_in,
> + real_out.file, pos_out, len);
> + break;
> + }
> + revert_creds(old_cred);
> +
> + /* Update size */
> + ovl_copyattr(ovl_inode_real(inode_out), inode_out);
> +
> + fdput(real_in);
> + fdput(real_out);
> +
> + return ret;
> +}
> +
> +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,
> + OVL_COPY);
> +}
> +
> +static int ovl_clone_file_range(struct file *file_in, loff_t pos_in,
> + struct file *file_out, loff_t pos_out, u64 len)
> +{
> + return ovl_copyfile(file_in, pos_in, file_out, pos_out, len, 0,
> + OVL_CLONE);
> +}
> +
> +static s64 ovl_dedupe_file_range(struct file *file_in, loff_t pos_in,
> + struct file *file_out, loff_t pos_out,
> + u64 len)
> +{
> + /*
> + * Don't copy up because of a dedupe request, this wouldn't make sense
> + * most of the time (data would be duplicated instead of deduplicated).
> + */
> + if (!ovl_inode_upper(file_inode(file_in)) ||
> + !ovl_inode_upper(file_inode(file_out)))
> + return -EPERM;

/me wonders, why not EOPNOTSUPP? That's what we've been using (in xfs
anyway) for "filesystem doesn't want to let you do this".

(Or I guess EXDEV, but "cross-device link not supported" might not be
quite what you want users to see...)

--D

> +
> + return ovl_copyfile(file_in, pos_in, file_out, pos_out, len, 0,
> + OVL_DEDUPE);
> +}
> +
> const struct file_operations ovl_file_operations = {
> .open = ovl_open,
> .release = ovl_release,
> @@ -393,4 +477,8 @@ const struct file_operations ovl_file_operations = {
> .fallocate = ovl_fallocate,
> .unlocked_ioctl = ovl_ioctl,
> .compat_ioctl = ovl_compat_ioctl,
> +
> + .copy_file_range = ovl_copy_file_range,
> + .clone_file_range = ovl_clone_file_range,
> + .dedupe_file_range = ovl_dedupe_file_range,
> };
> --
> 2.14.3
>

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