Re: [PATCH 3/7] cifs: smb2_close_getattr should also update i_size

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On Tue, Jan 23, 2024 at 12:52 PM Shyam Prasad N <nspmangalore@xxxxxxxxx> wrote:
>
> On Sun, Jan 21, 2024 at 9:03 AM <nspmangalore@xxxxxxxxx> wrote:
> >
> > From: Shyam Prasad N <sprasad@xxxxxxxxxxxxx>
> >
> > SMB2 CLOSE command with SMB2_CLOSE_FLAG_POSTQUERY_ATTRIB
> > flag set is already used by the code for SMB3+.
> > smb2_close_getattr is the function that uses this to
> > update the inode attributes.
> >
> > However, we were skipping the EndOfFile info that's returned
> > by the server. There is a small chance that the file size
> > may have been changed in the small window between the client
> > sending the close request (thereby giving up lease if it had)
> > to the point that the server returns the response.
> >
> > This change uses the field to update the inode size.
> > Also, it is a valid case for a zero AllocationSize to be returned
> > by the server for the file. We were discarding such values, thereby
> > resulting in stale i_blocks value. Fixed that here too.
> >
> > Signed-off-by: Shyam Prasad N <sprasad@xxxxxxxxxxxxx>
> > ---
> >  fs/smb/client/smb2ops.c | 6 +++---
> >  1 file changed, 3 insertions(+), 3 deletions(-)
> >
> > diff --git a/fs/smb/client/smb2ops.c b/fs/smb/client/smb2ops.c
> > index d9553c2556a2..e23577584ed6 100644
> > --- a/fs/smb/client/smb2ops.c
> > +++ b/fs/smb/client/smb2ops.c
> > @@ -1433,9 +1433,9 @@ smb2_close_getattr(const unsigned int xid, struct cifs_tcon *tcon,
> >          * but instead 512 byte (2**9) size is required for
> >          * calculating num blocks.
> >          */
> > -       if (le64_to_cpu(file_inf.AllocationSize) > 4096)
> > -               inode->i_blocks =
> > -                       (512 - 1 + le64_to_cpu(file_inf.AllocationSize)) >> 9;
> > +       inode->i_blocks = (512 - 1 + le64_to_cpu(file_inf.AllocationSize)) >> 9;
> > +
> > +       inode->i_size = le64_to_cpu(file_inf.EndOfFile);
> >
> >         /* End of file and Attributes should not have to be updated on close */
> >         spin_unlock(&inode->i_lock);
> > --
> > 2.34.1
> >
> Noticed a couple of things in other places in the code:
> 1. i_size_write() should be called instead of updating i_size directly.
> 2. There's a server_eof field that is generally maintained in sync
> with i_size. Need to check how that needs to be done here.
>
> I'll submit a v2 of this patch soon.
>
> --
> Regards,
> Shyam

Attached updated patch.

-- 
Regards,
Shyam

Attachment: 0001-cifs-smb2_close_getattr-should-also-update-i_size.patch
Description: Binary data


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