features/locks: Implement mandatory locks

Initial change to fix/enable the mandatory locking support in GlusterFS
as per the following design:

https://review.gluster.org/#/c/12014/

Accordingly 'locks.mandatory-locking' option is available as part of this
change which will accept one among the following values:

* off
* file
* forced
* optimal

See design doc for more details

> Reviewed-on: http://review.gluster.org/9768
> Smoke: Gluster Build System <jenkins@build.gluster.com>
> CentOS-regression: Gluster Build System <jenkins@build.gluster.com>
> NetBSD-regression: NetBSD Build System <jenkins@build.gluster.org>
> Reviewed-by: Poornima G <pgurusid@redhat.com>
> Reviewed-by: Raghavendra Talur <rtalur@redhat.com>
> Reviewed-by: Rajesh Joseph <rjoseph@redhat.com>
> Reviewed-by: Pranith Kumar Karampuri <pkarampu@redhat.com>

(cherry picked from commit 4517bf8dd6de310950cc5a612955aa3a2fddb57e)

Change-Id: I14c489b3f8af5ebcbfa155a03f0c175e9558ac46
BUG: 1332162
Signed-off-by: Anoop C S <anoopcs@redhat.com>
Reviewed-on: http://review.gluster.org/14149
Smoke: Gluster Build System <jenkins@build.gluster.com>
NetBSD-regression: NetBSD Build System <jenkins@build.gluster.org>
Reviewed-by: Niels de Vos <ndevos@redhat.com>
CentOS-regression: Gluster Build System <jenkins@build.gluster.com>

2 files changed, 218 insertions, 0 deletions

diff --git a/tests/features/mandatory-lock-forced.c b/tests/features/mandatory-lock-forced.c
new file mode 100644
index 00000000000..f37206845f1
--- /dev/null
+++ b/tests/features/mandatory-lock-forced.c
@@ -0,0 +1,138 @@
+#include <stdio.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/wait.h>
+
+#define LOG_ERR(func, err) do {                                                \
+        fprintf (stderr, "%s : returned error (%s)\n", func, strerror(err));   \
+        exit (err);                                                            \
+} while (0)
+
+int       fd;
+struct    flock lock;
+char      *buf = "ten bytes!";
+char      *fname = "/mnt/glusterfs/0/mand.lock";
+int       open_flags, child, err, status, blocked = 0;
+
+int do_child (char *argv[]) {
+        /* Initialize file open flags */
+        if (strcmp (argv[2], "BLOCK") == 0)
+                open_flags = O_RDWR;
+        else if (strcmp (argv[2], "TRUNC") == 0)
+                open_flags = O_RDWR | O_TRUNC | O_NONBLOCK;
+        else if (strcmp (argv[2], "NONE") == 0)
+                open_flags = O_RDWR | O_NONBLOCK;
+        else
+                LOG_ERR ("Invalid option:", EINVAL);
+
+        /* Open the file */
+        fd = open (fname, open_flags);
+        if (fd == -1)
+                LOG_ERR ("Child open", errno);
+
+        /* Perform the file operation*/
+        if (strcmp (argv[3], "READ") == 0) {
+                buf = NULL;
+                err = read (fd, buf, 10);
+                if (err == -1)
+                        LOG_ERR ("Child read", errno);
+        } else if (strcmp (argv[3], "WRITE") == 0) {
+                err = write (fd, buf, 10);
+                if (err == -1)
+                        LOG_ERR ("Child write", errno);
+        } else if (strcmp (argv[3], "FTRUNCATE") == 0) {
+                err = ftruncate (fd, 5);
+                if (err)
+                        LOG_ERR ("Child ftruncate", errno);
+        } else
+                LOG_ERR ("Invalid operation:", EINVAL);
+
+        /* Close child fd */
+        err = close (fd);
+        if (err)
+                LOG_ERR ("Child close", errno);
+
+        /* Exit success */
+        exit (0);
+}
+
+int main (int argc, char *argv[]) {
+        if (argc < 4) {
+                fprintf (stderr, "Wrong usage: Use as ./mandatory-lock "
+                                "<RD_LCK/WR_LCK> <BLOCK/TRUNC/NONE> "
+                                "<READ/WRITE/FTRUNCATE\n");
+                exit(EINVAL);
+        }
+        /* Create an empty lock file */
+        fd = open (fname, O_CREAT | O_RDWR, 0755);
+        if (fd == -1)
+                LOG_ERR ("Parent create", errno);
+
+        /* Determine the type of lock */
+        if (strcmp (argv[1], "RD_LCK") == 0)
+                lock.l_type = F_RDLCK;
+        else if (strcmp (argv[1], "WR_LCK") == 0)
+                lock.l_type = F_WRLCK;
+        else
+                LOG_ERR ("Parent lock type", EINVAL);
+
+        lock.l_whence = SEEK_SET;
+        lock.l_start = 0L;
+        lock.l_len = 0L;
+
+        /* Let parent acquire the initial lock */
+        err = fcntl (fd, F_SETLK, &lock);
+        if (err)
+                LOG_ERR ("Parent lock", errno);
+
+        /* Now fork a child */
+        child = fork ();
+        if (child == 0)
+                /* Perform the child operations */
+                do_child (argv);
+        else {
+                /* If blocking mode, then sleep for 2 seconds
+                 * and wait for the child */
+                if (strcmp (argv[2], "NONE") != 0) {
+                        sleep (2);
+                        if (waitpid (child, &status, WNOHANG) == 0)
+                                blocked = 1;
+                        /* Release the parent lock so that the
+                         * child can terminate */
+                        lock.l_type = F_UNLCK;
+                        err = fcntl (fd, F_SETLK, &lock);
+                        if (err)
+                                LOG_ERR ("Parent unlock", errno);
+                }
+
+                /* Wait for child to finish */
+                waitpid (child, &status, 0);
+
+                /* Close the parent fd */
+                err = close (fd);
+                if (err)
+                        LOG_ERR ("Parent close", errno);
+
+                /* Remove the lock file*/
+                err = unlink (fname);
+                if (err)
+                        LOG_ERR ("Parent unlink", errno);
+
+                /* If not blocked, exit with child exit status*/
+                errno = WEXITSTATUS(status);
+
+                /* If blocked, exit with corresponding
+                 * error code */
+                if (blocked)
+                        errno = EWOULDBLOCK;
+
+                if (errno != 0)
+                        printf ("%s\n", strerror(errno));
+
+                exit (errno);
+
+        }
+}
diff --git a/tests/features/mandatory-lock-forced.t b/tests/features/mandatory-lock-forced.t
new file mode 100644
index 00000000000..563669c6774
--- /dev/null
+++ b/tests/features/mandatory-lock-forced.t
@@ -0,0 +1,80 @@
+#!/bin/bash
+
+. $(dirname $0)/../include.rc
+. $(dirname $0)/../volume.rc
+
+cleanup;
+# Start glusterd [1]
+TEST glusterd
+
+# Create and verify the volume information [2-4]
+TEST $CLI volume create $V0 $H0:$B0/${V0}{1,2};
+EXPECT "$V0" volinfo_field $V0 'Volume Name';
+EXPECT 'Created' volinfo_field $V0 'Status';
+
+# Turn off the performance translators [5-9]
+TEST $CLI volume set $V0 performance.open-behind off
+TEST $CLI volume set $V0 performance.write-behind off
+TEST $CLI volume set $V0 performance.quick-read off
+TEST $CLI volume set $V0 performance.io-cache off
+TEST $CLI volume set $V0 performance.read-ahead off
+
+# Start and mount the volume [10-11]
+TEST $CLI volume start $V0;
+TEST $GFS --volfile-id=/$V0 --volfile-server=$H0 $M0
+
+build_tester $(dirname $0)/mandatory-lock-forced.c -o $(dirname $0)/mandatory-lock
+
+# Various read/write tests without enabling mandatory-locking [12-18]
+$(dirname $0)/mandatory-lock RD_LCK NONE READ
+TEST [ $? -eq 0 ]
+
+$(dirname $0)/mandatory-lock RD_LCK NONE WRITE
+TEST [ $? -eq 0 ]
+
+$(dirname $0)/mandatory-lock WR_LCK NONE READ
+TEST [ $? -eq 0 ]
+
+$(dirname $0)/mandatory-lock WR_LCK NONE WRITE
+TEST [ $? -eq 0 ]
+
+# Specifies O_TRUNC during open
+$(dirname $0)/mandatory-lock RD_LCK TRUNC READ
+TEST [ $? -eq 0 ]
+
+$(dirname $0)/mandatory-lock RD_LCK NONE FTRUNCATE
+TEST [ $? -eq 0 ]
+
+$(dirname $0)/mandatory-lock RD_LCK BLOCK WRITE
+TEST [ $? -eq 0 ]
+
+# Enable mandatory-locking [19]
+TEST $CLI volume set $V0 mandatory-locking forced
+
+# Restart the volume to take the change into effect [20-23]
+TEST umount $M0
+TEST $CLI volume stop $V0
+TEST $CLI volume start $V0
+TEST $GFS --volfile-id=/$V0 --volfile-server=$H0 $M0
+
+# Repeat the above tests with mandatory-locking [24-30]
+$(dirname $0)/mandatory-lock RD_LCK NONE READ
+TEST [ $? -eq 0 ]
+
+EXPECT "Resource temporarily unavailable" $(dirname $0)/mandatory-lock RD_LCK NONE WRITE
+
+EXPECT "Resource temporarily unavailable" $(dirname $0)/mandatory-lock WR_LCK NONE READ
+
+EXPECT "Resource temporarily unavailable" $(dirname $0)/mandatory-lock WR_LCK NONE WRITE
+
+EXPECT "Resource temporarily unavailable" $(dirname $0)/mandatory-lock RD_LCK TRUNC READ
+
+EXPECT "Resource temporarily unavailable" $(dirname $0)/mandatory-lock RD_LCK NONE FTRUNCATE
+
+EXPECT "Resource temporarily unavailable" $(dirname $0)/mandatory-lock RD_LCK BLOCK WRITE
+
+rm -rf $(dirname $0)/mandatory-lock
+
+cleanup
+
+#G_TESTDEF_TEST_STATUS_NETBSD7=KNOWN_ISSUE,BUG=1326464