gfapi: redesign the public interface for upcall consumers

The glfs_callback_arg and glfs_callback_inode_arg were allocated by
gfapi, and expected to be free()'d by the application. However it is not
reasonable to expect that applications use the same memory allocator to
as the compiled libgfapi.so. For instance, it is possible that gfapi
uses glibc malloc/free, and an application like NFS-Ganesha the versions
from jemalloc. Mismatching of the malloc() and free() functions causes
segmentation faults at best.

In order to prevent problems like this in the future, the API for
applications that consume upcalls has been remodeled. Any of the
structures that gfapi allocates, should be free'd with glfs_free(). The
members of the structures can not be accessed directly anymore, each
has its own function to access now.

Correcting the naming of the functions, structures and constants is a
continuation of commit 2775dc64101ed37c8d9809bf9852dbf0746ee2b6. These
new improvements not only have correct prefixes for the functions and
structures, the naming also reflects more to the upcall framework and
does not use "callback" anymore.

Cherry picked from commit 4721188a154acd9a0a4c096d8d73e97f3bf1b2a9:
> Change-Id: I2b8bd5a0a82036d2abea1a217f5e5975a1d4fe93
> BUG: 1344714
> Signed-off-by: Niels de Vos <ndevos@redhat.com>
> Reviewed-on: http://review.gluster.org/14701
> 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: Kaleb KEITHLEY <kkeithle@redhat.com>
> Reviewed-by: soumya k <skoduri@redhat.com>
> Reviewed-by: jiffin tony Thottan <jthottan@redhat.com>

Once difference with the version of this change in other branches is
that leases are not included in glusterfs-3.7. Hence there is a little
change that drops the handling of GF_UPCALL_RECALL_LEASE.

In addition, this backport contains commit 2775dc6410:
> libgfapi/upcall : prepend "glfs_" to callback_arg, callback_inode_arg
> Reviewed-on: http://review.gluster.org/14702

Change-Id: I2b8bd5a0a82036d2abea1a217f5e5975a1d4fe93
BUG: 1347715
Signed-off-by: Niels de Vos <ndevos@redhat.com>
Reviewed-on: http://review.gluster.org/15602
NetBSD-regression: NetBSD Build System <jenkins@build.gluster.org>
Smoke: Gluster Build System <jenkins@build.gluster.org>
CentOS-regression: Gluster Build System <jenkins@build.gluster.org>
Reviewed-by: Kaushal M <kaushal@redhat.com>

1 files changed, 52 insertions, 1 deletions

diff --git a/api/src/glfs-internal.h b/api/src/glfs-internal.h
index 6e99357d651..0d1f9e9b887 100644
--- a/api/src/glfs-internal.h
+++ b/api/src/glfs-internal.h
@@ -247,6 +247,26 @@ struct glfs_object {
         uuid_t          gfid;
 };
 
+struct glfs_upcall {
+        struct glfs             *fs;     /* glfs object */
+        enum glfs_upcall_reason  reason; /* Upcall event type */
+        void                    *event;  /* changes based in the event type */
+        void (*free_event)(void *);      /* free event after the usage */
+};
+
+struct glfs_upcall_inode {
+        struct glfs_object   *object;  /* Object which need to be acted upon */
+        int                   flags;   /* Cache UPDATE/INVALIDATE flags */
+        struct stat           buf;     /* Latest stat of this entry */
+        unsigned int          expire_time_attr; /* the amount of time for which
+                                                 * the application need to cache
+                                                 * this entry */
+        struct glfs_object   *p_object; /* parent Object to be updated */
+        struct stat           p_buf;    /* Latest stat of parent dir handle */
+        struct glfs_object   *oldp_object; /* Old parent Object to be updated */
+        struct stat           oldp_buf; /* Latest stat of old parent dir handle */
+};
+
 #define DEFAULT_EVENT_POOL_SIZE           16384
 #define GF_MEMPOOL_COUNT_OF_DICT_T        4096
 #define GF_MEMPOOL_COUNT_OF_DATA_T        (GF_MEMPOOL_COUNT_OF_DICT_T * 4)
@@ -423,7 +443,7 @@ int glfs_get_upcall_cache_invalidation (struct gf_upcall *to_up_data,
                                         struct gf_upcall *from_up_data);
 int
 glfs_h_poll_cache_invalidation (struct glfs *fs,
-                                struct callback_arg *up_arg,
+                                struct glfs_upcall *up_arg,
                                 struct gf_upcall *upcall_data);
 
 ssize_t
@@ -438,4 +458,35 @@ glfs_anonymous_pwritev (struct glfs *fs, struct glfs_object *object,
 struct glfs_object *
 glfs_h_resolve_symlink (struct glfs *fs, struct glfs_object *object);
 
+
+/* Deprecated structures that were passed to client applications, replaced by
+ * accessor functions. Do not use these in new applications, and update older
+ * usage.
+ *
+ * See http://review.gluster.org/14701 for more details.
+ *
+ * WARNING: These structures will be removed in the future.
+ */
+struct glfs_callback_arg {
+        struct glfs             *fs;
+        enum glfs_upcall_reason  reason;
+        void                    *event_arg;
+};
+
+struct glfs_callback_inode_arg {
+        struct glfs_object      *object; /* Object which need to be acted upon */
+        int                     flags; /* Cache UPDATE/INVALIDATE flags */
+        struct stat             buf; /* Latest stat of this entry */
+        unsigned int            expire_time_attr; /* the amount of time for which
+                                                   * the application need to cache
+                                                   * this entry
+                                                   */
+        struct glfs_object      *p_object; /* parent Object to be updated */
+        struct stat             p_buf; /* Latest stat of parent dir handle */
+        struct glfs_object      *oldp_object; /* Old parent Object
+                                               * to be updated */
+        struct stat             oldp_buf; /* Latest stat of old parent
+                                           * dir handle */
+};
+
 #endif /* !_GLFS_INTERNAL_H */