From: "Darrick J. Wong" <darrick.wong@oracle.com>
To: Miklos Szeredi <miklos@szeredi.hu>
Cc: Miklos Szeredi <mszeredi@redhat.com>,
overlayfs <linux-unionfs@vger.kernel.org>,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 21/35] ovl: add reflink/copyfile/dedup support
Date: Tue, 8 May 2018 07:38:02 -0700 [thread overview]
Message-ID: <20180508143802.GC9510@magnolia> (raw)
In-Reply-To: <CAJfpegu_iYLUeYU_OgZryFmCqa_a9MHt32nnsu7h_+JVXJ2d4w@mail.gmail.com>
On Tue, May 08, 2018 at 04:13:01PM +0200, Miklos Szeredi wrote:
> On Mon, May 7, 2018 at 10:43 PM, Darrick J. Wong
> <darrick.wong@oracle.com> wrote:
> > 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".
>
> EOPNOTSUPP might be interpreted as "this filesystem doesn't support
> dedupe", even though here it's just "these two particular files don't
> support dedupe".
ocfs2 already uses EOPNOTSUPP for 'these two particular files don't
support dedupe/reflink'. Granted, the manpage would seem to leave open
the possibility of using EOPNOTSUPP or EINVAL for the "can't do it to
these two files" case.
--D
> >
> > (Or I guess EXDEV, but "cross-device link not supported" might not be
> > quite what you want users to see...)
>
> Hmm, I like EPERM better. EPERM means something like "you can't do
> this for some unspecified reason". This is exactly the case here.
>
> Thanks,
> Miklos
next prev parent reply other threads:[~2018-05-08 14:38 UTC|newest]
Thread overview: 53+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-07 8:37 [PATCH v2 00/35] overlayfs: stack file operations Miklos Szeredi
2018-05-07 8:37 ` [PATCH v2 01/35] vfs: add path_open() Miklos Szeredi
2018-05-07 8:37 ` [PATCH v2 02/35] vfs: optionally don't account file in nr_files Miklos Szeredi
2018-05-07 8:37 ` [PATCH v2 03/35] vfs: add f_op->pre_mmap() Miklos Szeredi
2018-05-07 8:37 ` [PATCH v2 04/35] vfs: export vfs_ioctl() to modules Miklos Szeredi
2018-05-07 8:37 ` [PATCH v2 05/35] vfs: export vfs_dedupe_file_range_one() " Miklos Szeredi
2018-05-07 8:37 ` [PATCH v2 06/35] ovl: copy up times Miklos Szeredi
2018-05-07 8:37 ` [PATCH v2 07/35] ovl: copy up inode flags Miklos Szeredi
2018-05-07 8:37 ` [PATCH v2 08/35] Revert "Revert "ovl: get_write_access() in truncate"" Miklos Szeredi
2018-05-07 8:37 ` [PATCH v2 09/35] ovl: copy up file size as well Miklos Szeredi
2018-05-07 8:37 ` [PATCH v2 10/35] ovl: deal with overlay files in ovl_d_real() Miklos Szeredi
2018-05-07 13:17 ` Vivek Goyal
2018-05-07 8:37 ` [PATCH v2 11/35] ovl: stack file ops Miklos Szeredi
2018-05-07 8:37 ` [PATCH v2 12/35] ovl: add helper to return real file Miklos Szeredi
2018-05-07 8:37 ` [PATCH v2 13/35] ovl: add ovl_read_iter() Miklos Szeredi
2018-05-07 8:37 ` [PATCH v2 14/35] ovl: add ovl_write_iter() Miklos Szeredi
2018-05-07 8:37 ` [PATCH v2 15/35] ovl: add ovl_fsync() Miklos Szeredi
2018-05-08 5:14 ` Amir Goldstein
2018-05-08 14:57 ` Miklos Szeredi
2018-05-08 15:02 ` Amir Goldstein
2018-05-07 8:37 ` [PATCH v2 16/35] ovl: add ovl_mmap() Miklos Szeredi
2018-05-07 8:37 ` [PATCH v2 17/35] ovl: add ovl_fallocate() Miklos Szeredi
2018-05-07 8:37 ` [PATCH v2 18/35] ovl: add lsattr/chattr support Miklos Szeredi
2018-05-07 8:37 ` [PATCH v2 19/35] ovl: add ovl_fiemap() Miklos Szeredi
2018-05-07 8:37 ` [PATCH v2 20/35] ovl: add O_DIRECT support Miklos Szeredi
2018-05-07 8:37 ` [PATCH v2 21/35] ovl: add reflink/copyfile/dedup support Miklos Szeredi
2018-05-07 20:43 ` Darrick J. Wong
2018-05-08 14:13 ` Miklos Szeredi
2018-05-08 14:38 ` Darrick J. Wong [this message]
2018-05-07 8:37 ` [PATCH v2 22/35] vfs: don't open real Miklos Szeredi
2018-05-07 10:27 ` Amir Goldstein
2018-05-07 10:29 ` Miklos Szeredi
2018-05-11 18:54 ` Vivek Goyal
2018-05-11 19:42 ` Vivek Goyal
2018-05-14 13:58 ` Vivek Goyal
2018-05-15 20:42 ` Vivek Goyal
2018-05-14 14:03 ` Daniel Walsh
2018-05-07 8:37 ` [PATCH v2 23/35] ovl: copy-up on MAP_SHARED Miklos Szeredi
2018-05-07 19:28 ` Randy Dunlap
2018-05-08 15:03 ` Miklos Szeredi
2018-05-07 8:37 ` [PATCH v2 24/35] vfs: simplify dentry_open() Miklos Szeredi
2018-05-07 8:37 ` [PATCH v2 25/35] Revert "ovl: fix may_write_real() for overlayfs directories" Miklos Szeredi
2018-05-07 8:37 ` [PATCH v2 26/35] Revert "ovl: don't allow writing ioctl on lower layer" Miklos Szeredi
2018-05-07 8:37 ` [PATCH v2 27/35] vfs: fix freeze protection in mnt_want_write_file() for overlayfs Miklos Szeredi
2018-05-07 8:38 ` [PATCH v2 28/35] Revert "ovl: fix relatime for directories" Miklos Szeredi
2018-05-07 8:38 ` [PATCH v2 29/35] Revert "vfs: update ovl inode before relatime check" Miklos Szeredi
2018-05-07 8:38 ` [PATCH v2 30/35] Revert "vfs: add flags to d_real()" Miklos Szeredi
2018-05-07 8:38 ` [PATCH v2 31/35] Revert "vfs: do get_write_access() on upper layer of overlayfs" Miklos Szeredi
2018-05-07 8:38 ` [PATCH v2 32/35] Partially revert "locks: fix file locking on overlayfs" Miklos Szeredi
2018-05-08 15:15 ` Jeff Layton
2018-05-07 8:38 ` [PATCH v2 33/35] Revert "fsnotify: support overlayfs" Miklos Szeredi
2018-05-07 8:38 ` [PATCH v2 34/35] vfs: remove open_flags from d_real() Miklos Szeredi
2018-05-07 8:38 ` [PATCH v2 35/35] ovl: fix documentation of non-standard behavior Miklos Szeredi
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