From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Message-ID: <0833b9e12068007de42c681166a60a9cbaf0cb6b.camel@kernel.org> Subject: Re: [PATCH v4 01/11] VFS: move cross device copy_file_range() check into filesystems From: Jeff Layton Date: Sat, 27 Oct 2018 07:11:25 -0400 In-Reply-To: <20181026201057.36899-2-olga.kornievskaia@gmail.com> References: <20181026201057.36899-1-olga.kornievskaia@gmail.com> <20181026201057.36899-2-olga.kornievskaia@gmail.com> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Content-Transfer-Encoding: 7bit To: Olga Kornievskaia , trond.myklebust@hammerspace.com, anna.schumaker@netapp.com, viro@zeniv.linux.org.uk, smfrench@gmail.com, miklos@szeredi.hu Cc: linux-nfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-cifs@vger.kernel.org, linux-unionfs@vger.kernel.org, linux-man@vger.kernel.org List-ID: On Fri, 2018-10-26 at 16:10 -0400, Olga Kornievskaia wrote: > From: Olga Kornievskaia > > This patch makes it the responsibility of individual filesystems to > allow or deny cross device copies. Both NFS and CIFS have operations > for cross-server copies, and later patches will implement this feature. > > Note that as of this patch, the copy_file_range() function might be passed > superblocks from different filesystem types. -EXDEV should be returned > if cross device copies aren't supported, causing the VFS to fall back > on using do_splice_direct(). > > Signed-off-by: Olga Kornievskaia > --- > Documentation/filesystems/porting | 7 +++++++ > fs/cifs/cifsfs.c | 3 +++ > fs/nfs/nfs4file.c | 3 +++ > fs/overlayfs/file.c | 3 +++ > fs/read_write.c | 9 +++------ > 5 files changed, 19 insertions(+), 6 deletions(-) > > diff --git a/Documentation/filesystems/porting b/Documentation/filesystems/porting > index 7b7b845..897e1e7 100644 > --- a/Documentation/filesystems/porting > +++ b/Documentation/filesystems/porting > @@ -622,3 +622,10 @@ in your dentry operations instead. > alloc_file_clone(file, flags, ops) does not affect any caller's references. > On success you get a new struct file sharing the mount/dentry with the > original, on failure - ERR_PTR(). > +-- > +[mandatory] > + ->copy_file_range() may now be passed files which belong to two > + different superblocks of the same file system type or which belong > + to two different filesystems types all together. As before, the > + destination's copy_file_range() is the function which is called. > + If it cannot copy ranges from the source, it should return -EXDEV. > diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c > index 7065426..f2d7f4f 100644 > --- a/fs/cifs/cifsfs.c > +++ b/fs/cifs/cifsfs.c > @@ -1114,6 +1114,9 @@ static ssize_t cifs_copy_file_range(struct file *src_file, loff_t off, > unsigned int xid = get_xid(); > ssize_t rc; > > + if (src_file->f_inode->i_sb != dst_file->f_inode->i_sb) > + return -EXDEV; > + > rc = cifs_file_copychunk_range(xid, src_file, off, dst_file, destoff, > len, flags); > free_xid(xid); > diff --git a/fs/nfs/nfs4file.c b/fs/nfs/nfs4file.c > index 4288a6e..09df688 100644 > --- a/fs/nfs/nfs4file.c > +++ b/fs/nfs/nfs4file.c > @@ -135,6 +135,9 @@ static ssize_t nfs4_copy_file_range(struct file *file_in, loff_t pos_in, > { > ssize_t ret; > > + if (file_in->f_inode->i_sb != file_out->f_inode->i_sb) > + return -EXDEV; > + > if (file_inode(file_in) == file_inode(file_out)) > return -EINVAL; > retry: > diff --git a/fs/overlayfs/file.c b/fs/overlayfs/file.c > index aeaefd2..5282853 100644 > --- a/fs/overlayfs/file.c > +++ b/fs/overlayfs/file.c > @@ -483,6 +483,9 @@ 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) > { > + if (file_in->f_inode->i_sb != file_out->f_inode->i_sb) > + return -EXDEV; > + > return ovl_copyfile(file_in, pos_in, file_out, pos_out, len, flags, > OVL_COPY); > } > diff --git a/fs/read_write.c b/fs/read_write.c > index 39b4a21..fb4ffca 100644 > --- a/fs/read_write.c > +++ b/fs/read_write.c > @@ -1575,10 +1575,6 @@ ssize_t vfs_copy_file_range(struct file *file_in, loff_t pos_in, > (file_out->f_flags & O_APPEND)) > return -EBADF; > > - /* this could be relaxed once a method supports cross-fs copies */ > - if (inode_in->i_sb != inode_out->i_sb) > - return -EXDEV; > - > if (len == 0) > return 0; > > @@ -1588,7 +1584,8 @@ ssize_t vfs_copy_file_range(struct file *file_in, loff_t pos_in, > * Try cloning first, this is supported by more file systems, and > * more efficient if both clone and copy are supported (e.g. NFS). > */ > - if (file_in->f_op->clone_file_range) { > + if (inode_in->i_sb == inode_out->i_sb && > + file_in->f_op->clone_file_range) { > ret = file_in->f_op->clone_file_range(file_in, pos_in, > file_out, pos_out, len); > if (ret == 0) { > @@ -1600,7 +1597,7 @@ 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) > + if (ret != -EOPNOTSUPP && ret != -EXDEV) > goto done; > } > Yes, this is the right way to do this sort of change, IMO. Push the checks down into the fs' so they can be relaxed on a case-by-case basis. Modulo dchinner's comments, this looks fine. Reviewed-by: Jeff Layton