On Sat, Jan 22, 2011 at 6:38 AM, Jeff Layton <jlayton@xxxxxxxxx> wrote:
> On Fri, 21 Jan 2011 23:49:33 -0600
> Shirish Pargaonkar <shirishpargaonkar@xxxxxxxxx> wrote:
>
>> On Fri, Jan 21, 2011 at 4:04 PM, Jeff Layton <jlayton@xxxxxxxxx> wrote:
>> > On Fri, 21 Jan 2011 15:44:13 -0600
>> > shirishpargaonkar@xxxxxxxxx wrote:
>> >
>> >> From: Shirish Pargaonkar <shirishpargaonkar@xxxxxxxxx>
>> >>
>> >> A structure stored an rb tree is defined consisting of a SID and
>> >> a id (either uid or gid) to which that SID is mapped.
>> >>
>> >> Added fields needed to store this defined data structures of a
>> >> rb tree to a superblock and initialized them.
>> >>
>> >> There are two separate trees, one for SID/uid and another one for SID/gid.
>> >>
>> >>
>> >> Signed-off-by: Shirish Pargaonkar <shirishpargaonkar@xxxxxxxxx>
>> >> ---
>> >> fs/cifs/cifs_fs_sb.h | 4 ++++
>> >> fs/cifs/cifsacl.h | 6 ++++++
>> >> fs/cifs/cifsfs.c | 6 ++++++
>> >> 3 files changed, 16 insertions(+), 0 deletions(-)
>> >>
>> >> diff --git a/fs/cifs/cifs_fs_sb.h b/fs/cifs/cifs_fs_sb.h
>> >> index ac51cd2..4bd0680 100644
>> >> --- a/fs/cifs/cifs_fs_sb.h
>> >> +++ b/fs/cifs/cifs_fs_sb.h
>> >> @@ -45,6 +45,10 @@
>> >> struct cifs_sb_info {
>> >> struct rb_root tlink_tree;
>> >> spinlock_t tlink_tree_lock;
>> >> + struct rb_root uidtree;
>> >> + spinlock_t siduidlock;
>> >> + struct rb_root gidtree;
>> >> + spinlock_t sidgidlock;
>> >> struct tcon_link *master_tlink;
>> >> struct nls_table *local_nls;
>> >> unsigned int rsize;
>> >> diff --git a/fs/cifs/cifsacl.h b/fs/cifs/cifsacl.h
>> >> index c4ae7d0..6c26e7f 100644
>> >> --- a/fs/cifs/cifsacl.h
>> >> +++ b/fs/cifs/cifsacl.h
>> >> @@ -74,6 +74,12 @@ struct cifs_wksid {
>> >> char sidname[SIDNAMELENGTH];
>> >> } __attribute__((packed));
>> >>
>> >> +struct cifs_sid_id {
>> >> + struct rb_node rbnode;
>> >> + struct cifs_sid sid;
>> >> + unsigned long id;
>> >> +} __attribute__((packed));
>> >> +
>> >> extern int match_sid(struct cifs_sid *);
>> >> extern int compare_sids(const struct cifs_sid *, const struct cifs_sid *);
>> >>
>> >> diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
>> >> index a8323f1..36182e3 100644
>> >> --- a/fs/cifs/cifsfs.c
>> >> +++ b/fs/cifs/cifsfs.c
>> >> @@ -122,6 +122,12 @@ cifs_read_super(struct super_block *sb, void *data,
>> >> spin_lock_init(&cifs_sb->tlink_tree_lock);
>> >> cifs_sb->tlink_tree = RB_ROOT;
>> >>
>> >> + spin_lock_init(&cifs_sb->siduidlock);
>> >> + cifs_sb->uidtree = RB_ROOT;
>> >> +
>> >> + spin_lock_init(&cifs_sb->sidgidlock);
>> >> + cifs_sb->gidtree = RB_ROOT;
>> >> +
>> >> rc = bdi_setup_and_register(&cifs_sb->bdi, "cifs", BDI_CAP_MAP_COPY);
>> >> if (rc) {
>> >> kfree(cifs_sb);
>> >
>> > Why do you need per-sb caches? The upcall isn't specific to a
>> > particular superblock, so if you have more than one mount you'll have
>> > to do multiple upcalls for the same SID and have mutiple copies of the
>> > same cifs_sid_id in various caches. It seems like a global cache would
>> > be better.
>> >
>> > --
>> > Jeff Layton <jlayton@xxxxxxxxx>
>> >
>>
>> Yes, I will change it to a per server structure instead of a per superblock.
>
> Why a per-server cache though? Are you passing any information that's
> specific to the server to the upcall? It looks to me like all you pass
> is the SID. If two servers have files owned by the same SID, is there
> any need for a separate upcall and separate cache entries for them?
>
> --
> Jeff Layton <jlayton@xxxxxxxxx>
>
Yes, I think global cache will work since all SIDs are either unique or
well-known and same across all servers/domains/active directory.
Will make the change.
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