On Tue, Feb 15, 2011 at 2:16 PM, Jeff Layton <jlayton@xxxxxxxxxx> wrote:
> On Fri, 11 Feb 2011 12:48:56 -0600
> shirishpargaonkar@xxxxxxxxx wrote:
>
>> From: Shirish Pargaonkar <shirishpargaonkar@xxxxxxxxx>
>>
>>
>> Define (global) data structures to store ids, uids and gids, to which a
>> SID maps. There are two separate trees, one for SID/uid and another one
>> for SID/gid.
>>
>> A new type of key, cifs_idmap_key_type, is used.
>>
>> Keys are instantiated and searched using credential of the root by
>> overriding and restoring the credentials of the caller requesting the key.
>> Once a SID is mapped, it is stored along with the mapped id, in one
>> of the rb trees and key is released.
>>
>> Register a pruning function with the shrinker that prunes the rb trees
>> when memory pressure warrants freeing up cache. Just for now, it is
>> more like cleaning entire cache than pruning. The subsequent patch has
>> this function defined.
>>
>>
>> Signed-off-by: Shirish Pargaonkar <shirishpargaonkar@xxxxxxxxx>
>> ---
>> fs/cifs/cifsacl.c | 138 +++++++++++++++++++++++++++++++++++++++++++++++++++
>> fs/cifs/cifsfs.c | 7 +++
>> fs/cifs/cifsglob.h | 5 ++
>> fs/cifs/cifsproto.h | 3 +
>> 4 files changed, 153 insertions(+), 0 deletions(-)
>>
>> diff --git a/fs/cifs/cifsacl.c b/fs/cifs/cifsacl.c
>> index beeebf1..388b34c 100644
>> --- a/fs/cifs/cifsacl.c
>> +++ b/fs/cifs/cifsacl.c
>> @@ -23,6 +23,10 @@
>>
>> #include <linux/fs.h>
>> #include <linux/slab.h>
>> +#include <linux/string.h>
>> +#include <linux/keyctl.h>
>> +#include <linux/key-type.h>
>> +#include <keys/user-type.h>
>> #include "cifspdu.h"
>> #include "cifsglob.h"
>> #include "cifsacl.h"
>> @@ -50,6 +54,140 @@ static const struct cifs_sid sid_authusers = {
>> /* group users */
>> static const struct cifs_sid sid_user = {1, 2 , {0, 0, 0, 0, 0, 5}, {} };
>>
>> +static const struct cred *root_cred;
>> +
>> +/*
>> + * Run idmap cache shrinker.
>> + */
>> +static int
>> +cifs_idmap_shrinker(struct shrinker *shrink, int nr_to_scan, gfp_t gfp_mask)
>> +{
>> + /* Use a pruning scheme in a subsequent patch instead */
> ^^^^
> maybe add the standard "FIXME:" prefix? to the comment above?
>
>> + cifs_destroy_idmaptrees();
>> + return 0;
>> +}
>> +
>
> Aside from the trivial comment fix, this looks OK, I guess. Eventually
> it would be good to have a more selective pruning scheme than just
> dropping the entire idmap cache.
>
> Reviewed-by: Jeff Layton <jlayton@xxxxxxxxxx>
>
Jeff, that comment and invocation of function cifs_destroy_idmaptrees
goes away in the patch 2/2.
Regards,
Shirish
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