From db14ac2c81cc03084bfb63f393ac71a36e142266 Mon Sep 17 00:00:00 2001

From: Niels de Vos <ndevos@redhat.com>

Date: Tue, 16 May 2017 18:10:16 +0200

Subject: [PATCH 445/473] refcount: return pointer to the structure instead of

 a counter

There are no real users of the counter. It was thought of a handy tool

to track and debug refcounting, but it is not used at all. Some parts of

the code would benefit from a pointer getting returned instead.

Cherry picked from commit 2f0e9ab1ef271132b8b7b1af25e23ac7bb0720c8:

> BUG: 1399780

> Change-Id: I97e52c48420fed61be942ea27ff4849b803eed12

> Signed-off-by: Niels de Vos <ndevos@redhat.com>

> Reviewed-on: http://review.gluster.org/15971

> Smoke: Gluster Build System <jenkins@build.gluster.org>

> NetBSD-regression: NetBSD Build System <jenkins@build.gluster.org>

> CentOS-regression: Gluster Build System <jenkins@build.gluster.org>

> Reviewed-by: Xavier Hernandez <xhernandez@datalab.es>

> Reviewed-by: Kaleb KEITHLEY <kkeithle@redhat.com>

There has been a slight omission in the backport of change

I19d225b39aaa272d9005ba7adc3104c3764f1572. The return value of

GF_REF_GET() is used and causes compile warnings. The resulting build

with that backport may not function correctly without this change that

returns the pointer of the structure with GF_REF_GET().

Change-Id: I97e52c48420fed61be942ea27ff4849b803eed12

BUG: 1450336

Reported-by: Mohammed Rafi KC <rkavunga@redhat.com>

Signed-off-by: Niels de Vos <ndevos@redhat.com>

Reviewed-on: https://code.engineering.redhat.com/gerrit/106356

Reviewed-by: Poornima Gurusiddaiah <pgurusid@redhat.com>

Reviewed-by: Atin Mukherjee <amukherj@redhat.com>

---

 libglusterfs/src/refcount.c         | 21 +++++++--------------

 libglusterfs/src/refcount.h         | 10 +++++-----

 xlators/nfs/server/src/auth-cache.c | 10 ++++++----

 3 files changed, 18 insertions(+), 23 deletions(-)

diff --git a/libglusterfs/src/refcount.c b/libglusterfs/src/refcount.c

index 96edc10..9d33b73 100644

--- a/libglusterfs/src/refcount.c

+++ b/libglusterfs/src/refcount.c

@@ -13,7 +13,7 @@

 #ifndef REFCOUNT_NEEDS_LOCK

-unsigned int

+void *

 _gf_ref_get (gf_ref_t *ref)

 {

         unsigned int cnt = __sync_fetch_and_add (&ref->cnt, 1);

@@ -27,10 +27,10 @@ _gf_ref_get (gf_ref_t *ref)

          */

         GF_ASSERT (cnt != 0);

-        return cnt;

+        return cnt ? ref->data : NULL;

 }

-unsigned int

+void

 _gf_ref_put (gf_ref_t *ref)

 {

         unsigned int cnt = __sync_fetch_and_sub (&ref->cnt, 1);

@@ -43,18 +43,13 @@ _gf_ref_put (gf_ref_t *ref)

          */

         GF_ASSERT (cnt != 0);

-        if (cnt == 1 && ref->release) {

+        if (cnt == 1 && ref->release)

                 ref->release (ref->data);

-                /* set return value to 0 to inform the caller correctly */

-                cnt = 0;

-        }

-

-        return cnt;

 }

 #else

-unsigned int

+void *

 _gf_ref_get (gf_ref_t *ref)

 {

         unsigned int cnt = 0;

@@ -69,10 +64,10 @@ _gf_ref_get (gf_ref_t *ref)

         }

         UNLOCK (&ref->lk);

-        return cnt;

+        return cnt ? ref->data : NULL;

 }

-unsigned int

+void

 _gf_ref_put (gf_ref_t *ref)

 {

         unsigned int cnt = 0;

@@ -91,8 +86,6 @@ _gf_ref_put (gf_ref_t *ref)

         if (release && ref->release)

                 ref->release (ref->data);

-

-        return cnt;

 }

 #endif /* REFCOUNT_NEEDS_LOCK */

diff --git a/libglusterfs/src/refcount.h b/libglusterfs/src/refcount.h

index e850e63..db9432a 100644

--- a/libglusterfs/src/refcount.h

+++ b/libglusterfs/src/refcount.h

@@ -42,7 +42,7 @@ typedef struct _gf_ref_t gf_ref_t;

  *

  * @return: greater then 0 when a reference was taken, 0 when not

  */

-unsigned int

+void *

 _gf_ref_get (gf_ref_t *ref);

 /* _gf_ref_put -- decrease the refcount

@@ -50,7 +50,7 @@ _gf_ref_get (gf_ref_t *ref);

  * @return: greater then 0 when there are still references, 0 when cleanup

  *          should be done, gf_ref_release_t is called on cleanup

  */

-unsigned int

+void

 _gf_ref_put (gf_ref_t *ref);

 /* _gf_ref_init -- initalize an embedded refcount object

@@ -84,20 +84,20 @@ _gf_ref_init (gf_ref_t *ref, gf_ref_release_t release, void *data);

  *

  * Sets the refcount to 1.

  */

-#define GF_REF_INIT(p, d)   _gf_ref_init (&p->_ref, d, p)

+#define GF_REF_INIT(p, d)   _gf_ref_init (&(p)->_ref, d, p)

 /* GF_REF_GET -- increase the refcount of a GF_REF_DECL structure

  *

  * @return: greater then 0 when a reference was taken, 0 when not

  */

-#define GF_REF_GET(p)       _gf_ref_get (&p->_ref)

+#define GF_REF_GET(p)       _gf_ref_get (&(p)->_ref)

 /* GF_REF_PUT -- decrease the refcount of a GF_REF_DECL structure

  *

  * @return: greater then 0 when there are still references, 0 when cleanup

  *          should be done, gf_ref_release_t is called on cleanup

  */

-#define GF_REF_PUT(p)       _gf_ref_put (&p->_ref)

+#define GF_REF_PUT(p)       _gf_ref_put (&(p)->_ref)

 #endif /* _REFCOUNT_H */

diff --git a/xlators/nfs/server/src/auth-cache.c b/xlators/nfs/server/src/auth-cache.c

index 730e0a9..a901e80 100644

--- a/xlators/nfs/server/src/auth-cache.c

+++ b/xlators/nfs/server/src/auth-cache.c

@@ -145,8 +145,9 @@ auth_cache_add (struct auth_cache *cache, char *hashkey,

         GF_VALIDATE_OR_GOTO (GF_NFS, cache, out);

         GF_VALIDATE_OR_GOTO (GF_NFS, cache->cache_dict, out);

-        ret = GF_REF_GET (entry);

-        if (ret == 0) {

+        /* FIXME: entry is passed as parameter, this can never fail? */

+        entry = GF_REF_GET (entry);

+        if (!entry) {

                 /* entry does not have any references */

                 ret = -1;

                 goto out;

@@ -221,8 +222,9 @@ auth_cache_get (struct auth_cache *cache, char *hashkey,

                 if (!entry_data)

                         goto unlock;

-                lookup_res = (struct auth_cache_entry *)(entry_data->data);

-                if (GF_REF_GET (lookup_res) == 0) {

+                /* FIXME: this is dangerous use of entry_data */

+                lookup_res = GF_REF_GET ((struct auth_cache_entry *) entry_data->data);

+                if (lookup_res == NULL) {

                         /* entry has been free'd */

                         ret = ENTRY_EXPIRED;

                         goto unlock;

-- 

1.8.3.1