gNFS: Subdir mount does not work on UDP proto

After enabling nfs.mount-udp, mounting a subdir on a volume over
NFS fails. Because mountudpproc3_mnt_3_svc() invokes nfs3_rootfh()
which internally calls mnt3_mntpath_to_export() to resolve the
mount path. mnt3_mntpath_to_export() just works if the mount path
requested is volume itself. It is not able to resolve, if the path
is a subdir inside the volume.

MOUNT over TCP uses mnt3_find_export() to resolve subdir path but
UDP can't use this routine because mnt3_find_export() needs the
req data (of type rpcsvc_request_t) and it's available only for
TCP version of RPC.

FIX:
(1) Use syncop_lookup() framework to resolve the MOUNT PATH by
    breaking it into components and resolve component-by-component.
    i.e. glfs_resolve_at () API from libgfapi shared object.
(2) If MOUNT PATH is subdir, then make sure subdir export is not
    disabled.
(3) Add auth mechanism to respect nfs.rpc-auth-allow/reject and
    subdir auth i.e. nfs.export-dir
(4) Enhanced error handling for MOUNT over UDP

Change-Id: I42ee69415d064b98af4f49773026562824f684d1
BUG: 1118311
Signed-off-by: Santosh Kumar Pradhan <spradhan@redhat.com>
Reviewed-on: http://review.gluster.org/8346
Reviewed-by: soumya k <skoduri@redhat.com>
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Niels de Vos <ndevos@redhat.com>

1 files changed, 37 insertions, 0 deletions

diff --git a/api/src/glfs.c b/api/src/glfs.c
index bcabb29f857..c7c4c00450a 100644
--- a/api/src/glfs.c
+++ b/api/src/glfs.c
@@ -554,6 +554,43 @@ glfs_new (const char *volname)
 }
 
 
+struct glfs *
+glfs_new_from_ctx (glusterfs_ctx_t *ctx)
+{
+        struct glfs    *fs = NULL;
+
+        if (!ctx)
+                return NULL;
+
+        fs = GF_CALLOC (1, sizeof (*fs), glfs_mt_glfs_t);
+        if (!fs)
+                return NULL;
+        fs->ctx = ctx;
+
+        (void) pthread_cond_init (&fs->cond, NULL);
+
+        (void) pthread_mutex_init (&fs->mutex, NULL);
+
+        INIT_LIST_HEAD (&fs->openfds);
+
+        return fs;
+}
+
+
+void
+glfs_free_from_ctx (struct glfs *fs)
+{
+        if (!fs)
+                return;
+
+        (void) pthread_cond_destroy (&fs->cond);
+
+        (void) pthread_mutex_destroy (&fs->mutex);
+
+        GF_FREE (fs);
+}
+
+
 int
 glfs_set_volfile (struct glfs *fs, const char *volfile)
 {