gfapi: Fix IO error caused when there is consecutive graph switches

Issue:
Consider a simple situation, where glfs_init() is done, i.e. initial
graph is up. Now perform 2 volume sets that results in 2 client side
graph changes. After this perform some IO, the IO fails with ENOTCON.
The only way to recover this client is i guess another graph switch
or restart.

What actually is happening from code perspective:
Initial graph lets say A, followed by 2 consecutive graph switches
to B and C without any IO those two switches.

- graph_setup (A) as a result of GF_EVENT_CHILD_UP, and
fs->next_subvol = A

- glfs_init() results in fs->active_subvol = A, fs->next_subvol = NULL

- graph_setup (B) as a result of GF_EVENT_CHILD_UP, and
fs->next_subvol = B

- graph_setup (C) as a result of GF_EVENT_CHILD_UP, and
fs->next_subvol = C. It also sees that the previous graph B was never
set as fs->active_subvol, i.e. no IO or anything happened on B, so
can safely send GF_EVENT_PARENT_DOWN (by calling glfs_subvol_done(B)).
This parent down on B, results in child_down(B), which is fine.
But child_down also triggers graph_setup(B).

- graph_setup(B) as a result of GF_EVENT_CHILD_DOWN, and
fs->next_subvol = B, and GF_EVENT_PARENT_DOWN on C as explained
above. This again leads to GF_EVENT_CHILD_DOWN on C.

- graph_setup(C) as a result of GF_EVENT_CHILD_DOWN, and
fs->next_subvol = C, and GF_EVENT_PARENT_DOWN on B as explained
above.

Thus both the graphs B and C are disconnected, and hence the ENOTCON

Solution:
Remove the call to graph_setup() when the event is GF_EVENT_CHILD_DOWN.
It don't see any reason why graph_setup should be called when there is
child_down. Not sure what the original reason was, to have graph_setup
in child_down. git hostory shows the first patch itself had this call.

> Reviewed-on: http://review.gluster.org/14656
> Smoke: Gluster Build System <jenkins@build.gluster.org>
> CentOS-regression: Gluster Build System <jenkins@build.gluster.org>
> NetBSD-regression: NetBSD Build System <jenkins@build.gluster.org>
> Reviewed-by: Jeff Darcy <jdarcy@redhat.com>

BUG: 1367294
Change-Id: I9de86555f66cc94a05649ac863b40ed3426ffd4b
Signed-off-by: Poornima G <pgurusid@redhat.com>
Signed-off-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Reviewed-on: http://review.gluster.org/14835
Smoke: Gluster Build System <jenkins@build.gluster.org>
CentOS-regression: Gluster Build System <jenkins@build.gluster.org>
NetBSD-regression: NetBSD Build System <jenkins@build.gluster.org>
Reviewed-by: Kaushal M <kaushal@redhat.com>

5 files changed, 185 insertions, 1 deletions

diff --git a/api/src/glfs-master.c b/api/src/glfs-master.c
index 77e2d53abb9..b49ce2c8447 100644
--- a/api/src/glfs-master.c
+++ b/api/src/glfs-master.c
@@ -110,7 +110,6 @@ notify (xlator_t *this, int event, void *data, ...)
                         pthread_cond_broadcast (&fs->child_down_cond);
                 }
                 pthread_mutex_unlock (&fs->mutex);
-		graph_setup (fs, graph);
 		glfs_init_done (fs, 1);
 		break;
 	case GF_EVENT_CHILD_CONNECTING:
diff --git a/tests/bugs/gfapi/bug-1093594.c b/tests/bugs/libgfapi/bug-1093594.c
index 8f5aa9be66c..8f5aa9be66c 100644
--- a/tests/bugs/gfapi/bug-1093594.c
+++ b/tests/bugs/libgfapi/bug-1093594.c
diff --git a/tests/bugs/gfapi/bug-1093594.sh b/tests/bugs/libgfapi/bug-1093594.sh
index 444319b8e63..444319b8e63 100755
--- a/tests/bugs/gfapi/bug-1093594.sh
+++ b/tests/bugs/libgfapi/bug-1093594.sh
diff --git a/tests/bugs/libgfapi/glfs_vol_set_IO_ERR.c b/tests/bugs/libgfapi/glfs_vol_set_IO_ERR.c
new file mode 100644
index 00000000000..4cf849484a6
--- /dev/null
+++ b/tests/bugs/libgfapi/glfs_vol_set_IO_ERR.c
@@ -0,0 +1,165 @@
+#include <glusterfs/api/glfs.h>
+#include <glusterfs/api/glfs-handles.h>
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#define WRITE_SIZE (128)
+
+glfs_t *
+setup_new_client(char *volname, char *log_fileile)
+{
+        int ret = 0;
+        glfs_t *fs = NULL;
+
+        fs = glfs_new (volname);
+        if (!fs) {
+                fprintf (stderr, "\nglfs_new: returned NULL (%s)\n",
+                                 strerror (errno));
+                goto error;
+        }
+
+        ret = glfs_set_volfile_server (fs, "tcp", "localhost", 24007);
+        if (ret < 0) {
+                fprintf (stderr, "\nglfs_set_volfile_server failed ret:%d (%s)\n",
+                                 ret, strerror (errno));
+                goto error;
+        }
+
+        ret = glfs_set_logging (fs, log_fileile, 7);
+        if (ret < 0) {
+                fprintf (stderr, "\nglfs_set_logging failed with ret: %d (%s)\n",
+                                 ret, strerror (errno));
+                goto error;
+        }
+
+        ret = glfs_init (fs);
+        if (ret < 0) {
+                fprintf (stderr, "\nglfs_init failed with ret: %d (%s)\n",
+                                  ret, strerror (errno));
+                goto error;
+        }
+        return fs;
+error:
+        return NULL;
+}
+
+int
+write_something (glfs_t *fs)
+{
+        glfs_fd_t *fd       = NULL;
+        char      *buf      = NULL;
+        int       ret       = 0;
+        int       j         = 0;
+
+        fd = glfs_creat (fs, "filename", O_RDWR, 0644);
+        if (!fd) {
+                fprintf (stderr, "%s: (%p) %s\n", "filename", fd,
+                        strerror (errno));
+                return -1;
+        }
+
+        buf = (char *) malloc (WRITE_SIZE);
+        memset (buf, '-', WRITE_SIZE);
+
+        for (j = 0; j < 4; j++) {
+                ret = glfs_write (fd, buf, WRITE_SIZE, 0);
+                if (ret < 0) {
+                        fprintf (stderr, "Write(%s): %d (%s)\n", "filename", ret,
+                                strerror (errno));
+                        return ret;
+                }
+                glfs_lseek (fd, 0, SEEK_SET);
+        }
+        return 0;
+}
+
+static int
+volfile_change (const char *volname) {
+        int   ret = 0;
+        char *cmd = NULL, *cmd1 = NULL;
+
+        ret = asprintf (&cmd, "gluster volume set %s quick-read on",
+                        volname);
+        if (ret < 0) {
+                fprintf (stderr, "cannot construct cli command string (%s)",
+                         strerror (errno));
+                return ret;
+        }
+
+        ret = asprintf (&cmd1, "gluster volume set %s quick-read off",
+                        volname);
+        if (ret < 0) {
+                fprintf (stderr, "cannot construct cli command string (%s)",
+                         strerror (errno));
+                return ret;
+        }
+
+        ret = system (cmd);
+        if (ret < 0) {
+                fprintf (stderr, "quick-read off on (%s) failed", volname);
+                return ret;
+        }
+
+        ret = system (cmd1);
+        if (ret < 0) {
+                fprintf (stderr, "quick-read on on (%s) failed", volname);
+                return ret;
+        }
+
+        ret = system (cmd);
+        if (ret < 0) {
+                fprintf (stderr, "quick-read off on (%s) failed", volname);
+                return ret;
+        }
+
+        free (cmd);
+        free (cmd1);
+        return ret;
+}
+
+int
+main (int argc, char *argv[])
+{
+        int        ret      = 0;
+        glfs_t    *fs       = NULL;
+	char       buf[100];
+        glfs_fd_t *fd       = NULL;
+
+        if (argc != 3) {
+                fprintf (stderr,
+                                "Expect following args %s <Vol> <log file location>\n"
+                                , argv[0]);
+                return -1;
+        }
+
+        fs = setup_new_client (argv[1], argv[2]);
+	if (!fs)
+		goto error;
+
+        ret = volfile_change (argv[1]);
+        if (ret < 0)
+                goto error;
+
+        /* This is required as volfile change takes a while to reach this
+         * gfapi client and precess the graph change. Without this the issue
+         * cannot be reproduced as in cannot be tested.
+         */
+        sleep (10);
+
+	ret = write_something (fs);
+        if (ret < 0)
+                goto error;
+
+        ret = glfs_fini (fs);
+        if (ret < 0) {
+                fprintf (stderr, "glfs_fini failed with ret: %d (%s)\n",
+                         ret, strerror (errno));
+                goto error;
+        }
+
+        return 0;
+error:
+        return -1;
+}
diff --git a/tests/bugs/libgfapi/glfs_vol_set_IO_ERR.sh b/tests/bugs/libgfapi/glfs_vol_set_IO_ERR.sh
new file mode 100755
index 00000000000..43cad2b15ee
--- /dev/null
+++ b/tests/bugs/libgfapi/glfs_vol_set_IO_ERR.sh
@@ -0,0 +1,20 @@
+#!/bin/bash
+. $(dirname $0)/../../include.rc
+. $(dirname $0)/../../volume.rc
+
+cleanup;
+
+## Start and create a volume
+TEST glusterd;
+TEST pidof glusterd;
+TEST $CLI volume info;
+
+TEST $CLI volume create $V0 $H0:$B0/${V0}{1,2};
+TEST $CLI volume start $V0;
+logdir=`gluster --print-logdir`
+
+build_tester $(dirname $0)/glfs_vol_set_IO_ERR.c -lgfapi
+TEST $(dirname $0)/glfs_vol_set_IO_ERR $V0 $logdir/glfs_vol_set_IO_ERR.log
+
+cleanup_tester $(dirname $0)/glfs_vol_set_IO_ERR
+cleanup;