src/patches/suse-2.6.27.39/patches.fixes/nfsd-07-nfsd-idmap-drop-special-request-deferal-in-favour-of.patch

   1 Patch-mainline: submitted 04aug2009
   2 References: bnc#498708
   3 From: NeilBrown <neilb@suse.de>
   4 Date: Tue, 4 Aug 2009 15:06:39 +1000
   5 Subject: [PATCH 09/12] nfsd/idmap: drop special request deferal in favour of improved default.
   6
   7 The idmap code manages request deferal by waiting for a reply from
   8 userspace rather than putting the NFS request on a queue to be retried
   9 from the start.
  10 Now that the comment deferal code does this there is no need for the
  11 special code in idmap.
  12
  13 Signed-off-by: NeilBrown <neilb@suse.de>
  14
  15 ---
  16  fs/nfsd/nfs4idmap.c |  105 +++++-----------------------------------------------
  17  1 file changed, 11 insertions(+), 94 deletions(-)
  18
  19 --- linux-2.6.27-SLE11_BRANCH.orig/fs/nfsd/nfs4idmap.c
  20 +++ linux-2.6.27-SLE11_BRANCH/fs/nfsd/nfs4idmap.c
  21 @@ -485,109 +485,26 @@ nfsd_idmap_shutdown(void)
  22         cache_unregister(&nametoid_cache);
  23  }
  24
  25 -/*
  26 - * Deferred request handling
  27 - */
  28 -
  29 -struct idmap_defer_req {
  30 -       struct cache_req                req;
  31 -       struct cache_deferred_req deferred_req;
  32 -       wait_queue_head_t       waitq;
  33 -       atomic_t                        count;
  34 -};
  35 -
  36 -static inline void
  37 -put_mdr(struct idmap_defer_req *mdr)
  38 -{
  39 -       if (atomic_dec_and_test(&mdr->count))
  40 -               kfree(mdr);
  41 -}
  42 -
  43 -static inline void
  44 -get_mdr(struct idmap_defer_req *mdr)
  45 -{
  46 -       atomic_inc(&mdr->count);
  47 -}
  48 -
  49 -static void
  50 -idmap_revisit(struct cache_deferred_req *dreq, int toomany)
  51 -{
  52 -       struct idmap_defer_req *mdr =
  53 -               container_of(dreq, struct idmap_defer_req, deferred_req);
  54 -
  55 -       wake_up(&mdr->waitq);
  56 -       put_mdr(mdr);
  57 -}
  58 -
  59 -static struct cache_deferred_req *
  60 -idmap_defer(struct cache_req *req)
  61 -{
  62 -       struct idmap_defer_req *mdr =
  63 -               container_of(req, struct idmap_defer_req, req);
  64 -
  65 -       mdr->deferred_req.revisit = idmap_revisit;
  66 -       get_mdr(mdr);
  67 -       return (&mdr->deferred_req);
  68 -}
  69 -
  70 -static inline int
  71 -do_idmap_lookup(struct ent *(*lookup_fn)(struct ent *), struct ent *key,
  72 -               struct cache_detail *detail, struct ent **item,
  73 -               struct idmap_defer_req *mdr)
  74 -{
  75 -       *item = lookup_fn(key);
  76 -       if (!*item)
  77 -               return -ENOMEM;
  78 -       return cache_check(detail, &(*item)->h, &mdr->req);
  79 -}
  80 -
  81 -static inline int
  82 -do_idmap_lookup_nowait(struct ent *(*lookup_fn)(struct ent *),
  83 -                       struct ent *key, struct cache_detail *detail,
  84 -                       struct ent **item)
  85 -{
  86 -       int ret = -ENOMEM;
  87 -
  88 -       *item = lookup_fn(key);
  89 -       if (!*item)
  90 -               goto out_err;
  91 -       ret = -ETIMEDOUT;
  92 -       if (!test_bit(CACHE_VALID, &(*item)->h.flags)
  93 -                       || (*item)->h.expiry_time < get_seconds()
  94 -                       || detail->flush_time > (*item)->h.last_refresh)
  95 -               goto out_put;
  96 -       ret = -ENOENT;
  97 -       if (test_bit(CACHE_NEGATIVE, &(*item)->h.flags))
  98 -               goto out_put;
  99 -       return 0;
 100 -out_put:
 101 -       cache_put(&(*item)->h, detail);
 102 -out_err:
 103 -       *item = NULL;
 104 -       return ret;
 105 -}
 106 -
 107  static int
 108  idmap_lookup(struct svc_rqst *rqstp,
 109                 struct ent *(*lookup_fn)(struct ent *), struct ent *key,
 110                 struct cache_detail *detail, struct ent **item)
 111  {
 112 -       struct idmap_defer_req *mdr;
 113         int ret;
 114
 115 -       mdr = kzalloc(sizeof(*mdr), GFP_KERNEL);
 116 -       if (!mdr)
 117 +       *item = lookup_fn(key);
 118 +       if (!*item)
 119                 return -ENOMEM;
 120 -       atomic_set(&mdr->count, 1);
 121 -       init_waitqueue_head(&mdr->waitq);
 122 -       mdr->req.defer = idmap_defer;
 123 -       ret = do_idmap_lookup(lookup_fn, key, detail, item, mdr);
 124 -       if (ret == -EAGAIN) {
 125 -               wait_event_interruptible_timeout(mdr->waitq,
 126 -                       test_bit(CACHE_VALID, &(*item)->h.flags), 1 * HZ);
 127 -               ret = do_idmap_lookup_nowait(lookup_fn, key, detail, item);
 128 + retry:
 129 +       ret = cache_check(detail, &(*item)->h, &rqstp->rq_chandle);
 130 +
 131 +       if (ret == -ETIMEDOUT) {
 132 +               struct ent *prev_item = *item;
 133 +               *item = lookup_fn(key);
 134 +               if (*item != prev_item)
 135 +                       goto retry;
 136 +               cache_put(&(*item)->h, detail);
 137         }
 138 -       put_mdr(mdr);
 139         return ret;
 140  }
 141