On Tue, Oct 26, 2010 at 9:25 AM, Jeff Layton <jlayton@xxxxxxxxxx> wrote:
> On Tue, 26 Oct 2010 17:01:26 +0400
> Pavel Shilovsky <piastryyy@xxxxxxxxx> wrote:
>
>> When we close the last file handle of the inode we should invalidate it
>> to prevent data coherency problem when we open it again but it has been
>> modified by other clients.
>>
>> Signed-off-by: Pavel Shilovsky <piastryyy@xxxxxxxxx>
>> ---
>> fs/cifs/file.c | 14 ++++++++++++--
>> 1 files changed, 12 insertions(+), 2 deletions(-)
>>
>> diff --git a/fs/cifs/file.c b/fs/cifs/file.c
>> index d7c212a..02a045e 100644
>> --- a/fs/cifs/file.c
>> +++ b/fs/cifs/file.c
>> @@ -150,8 +150,14 @@ client_can_cache:
>> pCifsInode->clientCanCacheAll = true;
>> pCifsInode->clientCanCacheRead = true;
>> cFYI(1, "Exclusive Oplock granted on inode %p", inode);
>> - } else if ((oplock & 0xF) == OPLOCK_READ)
>> + } else if ((oplock & 0xF) == OPLOCK_READ) {
>> + pCifsInode->clientCanCacheAll = false;
>> pCifsInode->clientCanCacheRead = true;
>> + cFYI(1, "Level II Oplock franted on inode %p", inode);
>> + } else {
>> + pCifsInode->clientCanCacheAll = false;
>> + pCifsInode->clientCanCacheRead = false;
>> + }
>>
>
> The oplock handling in cifs is rather ad-hoc. There's a lot of
> cut-and-pasted code that sets that clientCanCache flags. The flags
> themselves are also sort of hard to understand -- i.e. why is is "All"
> and not "Write"?
>
> This would be good opportunity to consolidate that code into helper
> functions and just call them from the appropriate places.
>
> Perhaps a helper function that takes an oplock value and sets the
> clientCanCache flags appropriately? Or...maybe consider doing away with
> the canCache flags and just store the oplock value in the inode and
> have helper macros or something that read that value and tell you what
> can be done with it.
>
> i.e.: CLIENT_CAN_CACHE_READ(inode), CLIENT_CAN_CACHE_WRITE(inode)
Remember that the reason we don't have a can_cache_write is that there
is no equivalent smb/cifs protocol concept as "can_cache_write"
independent of caching reads - there are basically three types:
1) batch oplocks (read/write and open/close caching) which we don't
use (although will in smb2)
2) read/write
3) read
--
Thanks,
Steve
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