On Thu, May 26, 2011 at 10:20 AM, Jeff Layton <jlayton@xxxxxxxxxxxxxxx> wrote:
> On Thu, 26 May 2011 10:02:01 +0400
> Pavel Shilovsky <piastry@xxxxxxxxxxx> wrote:
>
>> Add cifs_match_super to use in sget to share superblock between mounts
>> that have the same //server/sharename, credentials and mount options.
>> It helps us to improve performance on work with future SMB2.1 leases.
<snip>
>> +static int
>> +compare_mount_options(struct super_block *sb, struct cifs_mnt_data *mnt_data)
>> +{
>> + struct cifs_sb_info *old = CIFS_SB(sb);
>> + struct cifs_sb_info *new = mnt_data->cifs_sb;
>> +
>> + if ((sb->s_flags & CIFS_MS_MASK) != (mnt_data->flags & CIFS_MS_MASK))
>> + return 0;
>> +
>> + if ((old->mnt_cifs_flags & CIFS_MOUNT_MASK) !=
>> + (new->mnt_cifs_flags & CIFS_MOUNT_MASK))
>> + return 0;
>> +
>> + if (old->rsize != new->rsize)
>> + return 0;
>> +
>> + if (new->wsize && new->wsize > old->wsize)
>> + return 0;
>> +
>
> ...also I think the above condition should be reversed. We don't want
> to match if new->wsize is smaller than the existing one. Since the
> specified wsize is just a starting point for negotiation, wsize now
> means "any wsize less than or equal to this size". If the old->wsize is
> bigger than that, then it's outside that range and we shouldn't match.
A more important question is whether the user intentionally tried to
specify a wsize. I don't see a problem matching a new default mount
request (with no wsize specified, using therefore a default wsize)
with an existing mount (with a larger explicitly specified wsize).
If a user explicitly requests to override to a particular wsize on the 2nd
mount - seems more logical to give them what they ask for if
possible whether larger or smaller.
--
Thanks,
Steve
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