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

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Message-ID: <CAH2r5mt5iXtarkUAY7PSMGOLhkQd5LFcEz-rAnTkayxQMq_ppA@mail.gmail.com>
Date:   Mon, 29 Aug 2022 00:06:41 -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

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

View attachment "use-filemap_write_and_wait_range.patch" of type "text/x-patch" (839 bytes)