2011/5/26 Steve French <smfrench@xxxxxxxxx>:
> 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.
>
If I understand right, Jeff suggested to change wsize logic to: "less
or equal that specified one". In this case we can share any sb that
match this criteria. So, in this case it should be "if (new->wsize &&
new->wsize <= old->wsize) return 0;"
--
Best regards,
Pavel Shilovsky.
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