protocol/client: Added lk_ctx info in fdctx dump

- Added a brief explanation as to why we can't use gf_log
  when in statedump.

- Removed gf_log messages from client_priv_dump since
  it can cause a 'deadlock' - See statedump.c for explanation

- Added try-lock based accessors for fd_lk_list for dump purposes.

Change-Id: I1d755a4ef2c568acf22fb8c4ab0a33a4f5fd07b4
BUG: 789858
Signed-off-by: Krishnan Parthasarathi <kp@gluster.com>
Reviewed-on: http://review.gluster.com/2882
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Amar Tumballi <amarts@redhat.com>
Reviewed-by: Vijay Bellur <vijay@gluster.com>

4 files changed, 83 insertions, 27 deletions

diff --git a/xlators/protocol/client/src/client-handshake.c b/xlators/protocol/client/src/client-handshake.c
index 34222f845a1..6d6e8ebc77b 100644
--- a/xlators/protocol/client/src/client-handshake.c
+++ b/xlators/protocol/client/src/client-handshake.c
@@ -470,22 +470,6 @@ out:
 }
 
 int
-client_fd_lk_list_empty (fd_lk_ctx_t *lk_ctx)
-{
-        int  ret = 1;
-
-        GF_VALIDATE_OR_GOTO ("client", lk_ctx, out);
-
-        LOCK (&lk_ctx->lock);
-        {
-                ret = list_empty (&lk_ctx->lk_list);
-        }
-        UNLOCK (&lk_ctx->lock);
-out:
-        return ret;
-}
-
-int
 client_fd_lk_count (fd_lk_ctx_t *lk_ctx)
 {
         int               count     = 0;
@@ -789,7 +773,7 @@ client_reacquire_lock (xlator_t *this, clnt_fd_ctx_t *fdctx)
         int32_t          ret       = -1;
         fd_lk_ctx_t     *lk_ctx    = NULL;
 
-        if (client_fd_lk_list_empty (fdctx->lk_ctx)) {
+        if (client_fd_lk_list_empty (fdctx->lk_ctx, _gf_false)) {
                 gf_log (this->name, GF_LOG_WARNING,
                         "fd lock list is empty");
                 decrement_reopen_fd_count (this, (clnt_conf_t *)this->private);
@@ -874,7 +858,7 @@ client3_1_reopen_cbk (struct rpc_req *req, struct iovec *iov, int count,
                 fdctx->remote_fd = rsp.fd;
                 if (!fdctx->released) {
                         list_add_tail (&fdctx->sfd_pos, &conf->saved_fds);
-                        if (!client_fd_lk_list_empty (fdctx->lk_ctx))
+                        if (!client_fd_lk_list_empty (fdctx->lk_ctx, _gf_false))
                                 attempt_lock_recovery = _gf_true;
                         fdctx = NULL;
                 }
diff --git a/xlators/protocol/client/src/client-helpers.c b/xlators/protocol/client/src/client-helpers.c
index b9b0a0edf61..8cf83fe3094 100644
--- a/xlators/protocol/client/src/client-helpers.c
+++ b/xlators/protocol/client/src/client-helpers.c
@@ -26,6 +26,32 @@
 #include "fd.h"
 
 
+int
+client_fd_lk_list_empty (fd_lk_ctx_t *lk_ctx, gf_boolean_t try_lock)
+{
+        int  ret = 1;
+
+        if (!lk_ctx) {
+                ret = -1;
+                goto out;
+        }
+
+        if (try_lock) {
+                ret = TRY_LOCK (&lk_ctx->lock);
+                if (ret != 0) {
+                        ret = -1;
+                        goto out;
+                }
+        } else {
+                LOCK (&lk_ctx->lock);
+        }
+
+        ret = list_empty (&lk_ctx->lk_list);
+        UNLOCK (&lk_ctx->lock);
+out:
+        return ret;
+}
+
 clnt_fd_ctx_t *
 this_fd_del_ctx (fd_t *file, xlator_t *this)
 {
diff --git a/xlators/protocol/client/src/client.c b/xlators/protocol/client/src/client.c
index 19c8a62ee86..b954906c1ce 100644
--- a/xlators/protocol/client/src/client.c
+++ b/xlators/protocol/client/src/client.c
@@ -2409,6 +2409,54 @@ fini (xlator_t *this)
         return;
 }
 
+static void
+client_fd_lk_ctx_dump (xlator_t *this, fd_lk_ctx_t *lk_ctx, int nth_fd)
+{
+        gf_boolean_t            use_try_lock             = _gf_true;
+        int                     ret                      = -1;
+        int                     lock_no                  = 0;
+        fd_lk_ctx_t             *lk_ctx_ref              = NULL;
+        fd_lk_ctx_node_t        *plock                   = NULL;
+        char                    key[GF_DUMP_MAX_BUF_LEN] = {0,};
+
+        lk_ctx_ref = fd_lk_ctx_try_ref (lk_ctx);
+        if (!lk_ctx_ref)
+                return;
+
+        ret = client_fd_lk_list_empty (lk_ctx_ref, (use_try_lock = _gf_true));
+        if (ret != 0)
+                return;
+
+        ret = TRY_LOCK (&lk_ctx_ref->lock);
+        if (ret)
+                return;
+
+        gf_proc_dump_write ("------","------");
+
+        lock_no = 0;
+        list_for_each_entry (plock, &lk_ctx_ref->lk_list, next) {
+                snprintf (key, sizeof (key), "granted-posix-lock[%d]",
+                          lock_no++);
+                gf_proc_dump_write (key, "owner = %s, cmd = %s "
+                                    "fl_type = %s, fl_start = %"
+                                    PRId64", fl_end = %"PRId64
+                                    ", user_flock: l_type = %s, "
+                                    "l_start = %"PRId64", l_len = %"PRId64,
+                                    lkowner_utoa (&plock->user_flock.l_owner),
+                                    get_lk_cmd (plock->cmd),
+                                    get_lk_type (plock->fl_type),
+                                    plock->fl_start, plock->fl_end,
+                                    get_lk_type (plock->user_flock.l_type),
+                                    plock->user_flock.l_start,
+                                    plock->user_flock.l_len);
+        }
+        gf_proc_dump_write ("------","------");
+
+        UNLOCK (&lk_ctx_ref->lock);
+        fd_lk_ctx_unref (lk_ctx_ref);
+
+}
+
 int
 client_priv_dump (xlator_t *this)
 {
@@ -2423,18 +2471,12 @@ client_priv_dump (xlator_t *this)
                 return -1;
 
         conf = this->private;
-        if (!conf) {
-                gf_log (this->name, GF_LOG_WARNING,
-                        "conf null in xlator");
+        if (!conf)
                 return -1;
-        }
 
         ret = pthread_mutex_trylock(&conf->lock);
-        if (ret) {
-                gf_log(this->name, GF_LOG_WARNING, "Unable to lock client %s"
-                       " errno: %d", this->name, errno);
+        if (ret)
                 return -1;
-        }
 
         gf_proc_dump_build_key(key_prefix, "xlator.protocol.client",
                                "%s.priv", this->name);
@@ -2442,8 +2484,10 @@ client_priv_dump (xlator_t *this)
         gf_proc_dump_add_section(key_prefix);
 
         list_for_each_entry(tmp, &conf->saved_fds, sfd_pos) {
-                sprintf (key, "fd.%d.remote_fd", ++i);
+                sprintf (key, "fd.%d.remote_fd", i);
                 gf_proc_dump_write(key, "%d", tmp->remote_fd);
+                client_fd_lk_ctx_dump (this, tmp->lk_ctx, i);
+                i++;
         }
 
         gf_proc_dump_write("connecting", "%d", conf->connecting);
diff --git a/xlators/protocol/client/src/client.h b/xlators/protocol/client/src/client.h
index f5f3aa1fec8..1f8f75cece5 100644
--- a/xlators/protocol/client/src/client.h
+++ b/xlators/protocol/client/src/client.h
@@ -229,4 +229,6 @@ int32_t client_type_to_gf_type (short l_type);
 int client_mark_fd_bad (xlator_t *this);
 
 int client_set_lk_version (xlator_t *this);
+
+int client_fd_lk_list_empty (fd_lk_ctx_t *lk_ctx, gf_boolean_t use_try_lock);
 #endif /* !_CLIENT_H */