performance/quick-read: use pthread_mutex_trylock to hold mutex in statedumps

Do not use pthread_mutex_lock and gf_log functions while dumping information
to statedump, to avoid deadlocks.

Change-Id: I0d30b04ae322f131b7a42d277ebd4385e83769e6
BUG: 843789
Signed-off-by: Raghavendra Bhat <raghavendra@redhat.com>
Reviewed-on: http://review.gluster.com/3764
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Anand Avati <avati@redhat.com>

1 files changed, 16 insertions, 3 deletions

diff --git a/xlators/performance/quick-read/src/quick-read.c b/xlators/performance/quick-read/src/quick-read.c
index 349ea778902..867900b902c 100644
--- a/xlators/performance/quick-read/src/quick-read.c
+++ b/xlators/performance/quick-read/src/quick-read.c
@@ -3431,6 +3431,7 @@ qr_inodectx_dump (xlator_t *this, inode_t *inode)
         int32_t     ret      = -1;
         char        key_prefix[GF_DUMP_MAX_BUF_LEN] = {0, };
         char        buf[256]                        = {0, };
+
         ret = inode_ctx_get (inode, this, &value);
         if (ret != 0) {
                 goto out;
@@ -3470,6 +3471,7 @@ qr_fdctx_dump (xlator_t *this, fd_t *fd)
         char         key[GF_DUMP_MAX_BUF_LEN]        = {0, };
         char         key_prefix[GF_DUMP_MAX_BUF_LEN] = {0, };
         call_stub_t *stub                            = NULL;
+        gf_boolean_t add_section                     = _gf_false;
 
         ret = fd_ctx_get (fd, this, &value);
         if (ret != 0) {
@@ -3484,13 +3486,16 @@ qr_fdctx_dump (xlator_t *this, fd_t *fd)
         gf_proc_dump_build_key (key_prefix, "xlator.performance.quick-read",
                                 "fdctx");
         gf_proc_dump_add_section (key_prefix);
+        add_section = _gf_true;
 
         gf_proc_dump_write ("fd", "%p", fd);
 
-        gf_proc_dump_write ("path", "%s", fdctx->path);
-
-        LOCK (&fdctx->lock);
+        ret = TRY_LOCK (&fdctx->lock);
+        if (ret)
+                goto out;
         {
+                gf_proc_dump_write ("path", "%s", fdctx->path);
+
                 gf_proc_dump_write ("opened", "%s", fdctx->opened ? "yes" : "no");
 
                 gf_proc_dump_write ("open-in-progress", "%s", fdctx->open_in_transit ?
@@ -3518,6 +3523,14 @@ qr_fdctx_dump (xlator_t *this, fd_t *fd)
 
         ret = 0;
 out:
+        if (ret && fdctx) {
+                if (add_section == _gf_false)
+                        gf_proc_dump_add_section (key_prefix);
+
+                gf_proc_dump_write ("Unable to dump the state of fdctx",
+                                    "(Lock acquistion failed) fd: %p, gfid: %s",
+                                    fd, uuid_utoa (fd->inode->gfid));
+        }
         return ret;
 }