linux-kernel - Re: [PATCH 1/5] smb3: Move the flush out of smb2_copychunk

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Message-ID: <CAH2r5msqTBu=wFn_wOaXucTn45WZfyNrAWqwpcGuxMFnpXyubA@mail.gmail.com>
Date:   Mon, 29 Aug 2022 11:56:58 -0500
From:   Steve French <smfrench@...il.com>
To:     David Howells <dhowells@...hat.com>
Cc:     sfrench@...ba.org, linux-cifs@...r.kernel.org,
        samba-technical@...ts.samba.org, jlayton@...nel.org,
        linux-kernel@...r.kernel.org, willy@...radead.org,
        lsahlber@...hat.com, dchinner@...hat.com,
        linux-fsdevel@...r.kernel.org
Subject: Re: [PATCH 1/5] smb3: Move the flush out of smb2_copychunk_range()
 into its callers

e.g. something like the following


On Mon, Aug 29, 2022 at 12:06 AM Steve French <smfrench@...il.com> wrote:
>
> Shouldn't this be using filemap_write_and_wait_range() not
> filemap_write_and_wait as we see in similar code in ext4 (and
> shouldn't it check rc in some of these cases)?   For example for the
> copychunk_range example shouldn't the patch be modified similar to the
> following:
>
> diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
> index e9fb338b8e7e..51963e83daf7 100644
> --- a/fs/cifs/cifsfs.c
> +++ b/fs/cifs/cifsfs.c
> @@ -1219,8 +1219,6 @@ ssize_t cifs_file_copychunk_range(unsigned int xid,
>
>         cifs_dbg(FYI, "copychunk range\n");
>
> -       filemap_write_and_wait(src_inode->i_mapping);
> -
>         if (!src_file->private_data || !dst_file->private_data) {
>                 rc = -EBADF;
>                 cifs_dbg(VFS, "missing cifsFileInfo on copy range src file\n");
> @@ -1250,6 +1248,12 @@ ssize_t cifs_file_copychunk_range(unsigned int xid,
>         lock_two_nondirectories(target_inode, src_inode);
>
>         cifs_dbg(FYI, "about to flush pages\n");
> +
> +       rc = filemap_write_and_wait_range(src_inode->i_mapping, off,
> +                                         off + len - 1);
> +        if (rc)
> +               goto out;
> +
>         /* should we flush first and last page first */
>         truncate_inode_pages(&target_inode->i_data, 0);
>
> On Tue, Aug 23, 2022 at 8:09 AM David Howells via samba-technical
> <samba-technical@...ts.samba.org> wrote:
> >
> > Move the flush out of smb2_copychunk_range() into its callers.  This will
> > allow the pagecache to be invalidated between the flush and the operation
> > in smb3_collapse_range() and smb3_insert_range().
> >
> > Signed-off-by: David Howells <dhowells@...hat.com>
> > cc: Steve French <stfrench@...rosoft.com>
> > cc: Ronnie Sahlberg <lsahlber@...hat.com>
> > ---
> >
> >  fs/cifs/cifsfs.c  |    2 ++
> >  fs/cifs/smb2ops.c |   20 ++++++++------------
> >  2 files changed, 10 insertions(+), 12 deletions(-)
> >
> > diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
> > index f54d8bf2732a..e9fb338b8e7e 100644
> > --- a/fs/cifs/cifsfs.c
> > +++ b/fs/cifs/cifsfs.c
> > @@ -1219,6 +1219,8 @@ ssize_t cifs_file_copychunk_range(unsigned int xid,
> >
> >         cifs_dbg(FYI, "copychunk range\n");
> >
> > +       filemap_write_and_wait(src_inode->i_mapping);
> > +
> >         if (!src_file->private_data || !dst_file->private_data) {
> >                 rc = -EBADF;
> >                 cifs_dbg(VFS, "missing cifsFileInfo on copy range src file\n");
> > diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
> > index 96f3b0573606..7e3de6a0e1dc 100644
> > --- a/fs/cifs/smb2ops.c
> > +++ b/fs/cifs/smb2ops.c
> > @@ -1600,17 +1600,8 @@ smb2_copychunk_range(const unsigned int xid,
> >         int chunks_copied = 0;
> >         bool chunk_sizes_updated = false;
> >         ssize_t bytes_written, total_bytes_written = 0;
> > -       struct inode *inode;
> >
> >         pcchunk = kmalloc(sizeof(struct copychunk_ioctl), GFP_KERNEL);
> > -
> > -       /*
> > -        * We need to flush all unwritten data before we can send the
> > -        * copychunk ioctl to the server.
> > -        */
> > -       inode = d_inode(trgtfile->dentry);
> > -       filemap_write_and_wait(inode->i_mapping);
> > -
> >         if (pcchunk == NULL)
> >                 return -ENOMEM;
> >
> > @@ -3689,6 +3680,8 @@ static long smb3_collapse_range(struct file *file, struct cifs_tcon *tcon,
> >                 goto out;
> >         }
> >
> > +       filemap_write_and_wait(inode->i_mapping);
> > +
> >         rc = smb2_copychunk_range(xid, cfile, cfile, off + len,
> >                                   i_size_read(inode) - off - len, off);
> >         if (rc < 0)
> > @@ -3716,18 +3709,21 @@ static long smb3_insert_range(struct file *file, struct cifs_tcon *tcon,
> >         int rc;
> >         unsigned int xid;
> >         struct cifsFileInfo *cfile = file->private_data;
> > +       struct inode *inode = file_inode(file);
> >         __le64 eof;
> >         __u64  count;
> >
> >         xid = get_xid();
> >
> > -       if (off >= i_size_read(file->f_inode)) {
> > +       if (off >= i_size_read(inode)) {
> >                 rc = -EINVAL;
> >                 goto out;
> >         }
> >
> > -       count = i_size_read(file->f_inode) - off;
> > -       eof = cpu_to_le64(i_size_read(file->f_inode) + len);
> > +       count = i_size_read(inode) - off;
> > +       eof = cpu_to_le64(i_size_read(inode) + len);
> > +
> > +       filemap_write_and_wait(inode->i_mapping);
> >
> >         rc = SMB2_set_eof(xid, tcon, cfile->fid.persistent_fid,
> >                           cfile->fid.volatile_fid, cfile->pid, &eof);
> >
> >
> >
>
>
> --
> Thanks,
>
> Steve



-- 
Thanks,

Steve

View attachment "0001-smb3-use-filemap_write_and_wait_range-instead-of-fil.patch" of type "text/x-patch" (2262 bytes)