CTDB with GlusterFS.
Ralph Boehme
rb at sernet.de
Fri Nov 13 17:24:48 UTC 2015
On Fri, Nov 13, 2015 at 10:28:05AM +0100, Ralph Boehme wrote:
> On Thu, Nov 12, 2015 at 01:51:40PM +1100, Martin Schwenke wrote:
> > On Wed, 11 Nov 2015 07:26:03 +0100, Ralph Boehme <rb at sernet.de> wrote:
> >
> > > On Wed, Nov 11, 2015 at 05:12:31PM +1100, Martin Schwenke wrote:
> > > > This would allow you to test the fcntl(2) locking without having all of
> > > > CTDB in the way.
> > > >
> > > > If you're not a C programmer (though I think this could probably be
> > > > done with Python too) then please yell and I'll whip something up for
> > > > you to test with... :-)
> > >
> > > fwiw, I have this WIP patch for ping_pong in a working branch.
> >
> > I think we discussed this some time ago and some of us thought there
> > were better ways. I think one reply was probably that it didn't
> > belong in ping_pong. Also, Michael pointed out another way using
> > existing ping_pong functionality.
> >
> > However, I think your patch creates a very obvious way of testing
> > byte-range locks and we should think about how it can be cleaned
> > up and pushed.
> >
> > You probably need to clean up the repetitive usage checking... :-)
>
> I'll cleanup and resubmit later on today.
updated patch attached.
I could split the modification of lock_range() into a seperate commit
if you prefer.
Thoughts?
-Ralph
--
SerNet GmbH, Bahnhofsallee 1b, 37081 Göttingen
phone: +49-551-370000-0, fax: +49-551-370000-9
AG Göttingen, HRB 2816, GF: Dr. Johannes Loxen
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-------------- next part --------------
From 68e7f6570f835a68abfad66a5ff75c7832435c07 Mon Sep 17 00:00:00 2001
From: Ralph Boehme <slow at samba.org>
Date: Sun, 10 May 2015 01:39:16 +0200
Subject: [PATCH] ping_pong: add -l option
Add a new option -l to check whether POSIX byte range locks are
working. Usage:
node1$ touch /path/to/cluster-fs/FILE
node1$ ./bin/ping_pong -l /path/to/cluster-fs/FILE
Holding lock, press any key to continue...
You should run the same command on another node now.
node2$ ./bin/ping_pong -l /path/to/cluster-fs/FILE
Output can either be:
Holding lock, press any key to continue...
This means POSIX byte range locks are *not* working.
If you see this instead:
file already locked, calling check_lock to tell us who has it locked...:
check_lock failed: lock held: pid='27375', type='1', start='0', len='0'
Working POSIX byte range locks
Congrats, you have a cluster fs with functional byte range locks!
Signed-off-by: Ralph Boehme <slow at samba.org>
---
ctdb/utils/ping_pong/ping_pong.c | 65 ++++++++++++++++++++++++++++++----------
1 file changed, 50 insertions(+), 15 deletions(-)
diff --git a/ctdb/utils/ping_pong/ping_pong.c b/ctdb/utils/ping_pong/ping_pong.c
index fdb575d..be43a1d 100644
--- a/ctdb/utils/ping_pong/ping_pong.c
+++ b/ctdb/utils/ping_pong/ping_pong.c
@@ -39,10 +39,11 @@
#include <unistd.h>
#include <fcntl.h>
#include <sys/mman.h>
+#include <stdbool.h>
static struct timeval tp1,tp2;
-static int do_reads, do_writes, use_mmap, do_check;
+static int do_reads, do_writes, use_mmap, do_check, do_brl_test;
static void start_timer(void)
{
@@ -57,7 +58,7 @@ static double end_timer(void)
}
/* lock a byte range in a open file */
-static int lock_range(int fd, int offset, int len)
+static int lock_range(int fd, int offset, int len, bool wait)
{
struct flock lock;
@@ -67,7 +68,7 @@ static int lock_range(int fd, int offset, int len)
lock.l_len = len;
lock.l_pid = 0;
- return fcntl(fd,F_SETLKW,&lock);
+ return fcntl(fd, wait ? F_SETLKW : F_SETLK, &lock);
}
/* check whether we could place a lock */
@@ -147,11 +148,11 @@ static void ping_pong(int fd, int num_locks)
start_timer();
- lock_range(fd, 0, 1);
+ lock_range(fd, 0, 1, true);
i = 0;
while (1) {
- if (lock_range(fd, (i+1) % num_locks, 1) != 0) {
+ if (lock_range(fd, (i+1) % num_locks, 1, true) != 0) {
printf("lock at %d failed! - %s\n",
(i+1) % num_locks, strerror(errno));
}
@@ -198,13 +199,25 @@ static void ping_pong(int fd, int num_locks)
}
}
+static void usage(void)
+{
+ printf("ping_pong -rwmc <file> <num_locks>\n");
+ printf("ping_pong -l <file>\n\n");
+ printf("Options\n");
+ printf(" -r do reads\n");
+ printf(" -w do writes\n");
+ printf(" -m use mmap\n");
+ printf(" -c check locks\n");
+ printf(" -l test for working byte range locks\n");
+}
+
int main(int argc, char *argv[])
{
char *fname;
int fd, num_locks;
int c;
- while ((c = getopt(argc, argv, "rwmc")) != -1) {
+ while ((c = getopt(argc, argv, "rwmcl")) != -1) {
switch (c){
case 'w':
do_writes = 1;
@@ -218,6 +231,9 @@ int main(int argc, char *argv[])
case 'c':
do_check = 1;
break;
+ case 'l':
+ do_brl_test = 1;
+ break;
default:
fprintf(stderr, "Unknown option '%c'\n", c);
exit(1);
@@ -227,25 +243,44 @@ int main(int argc, char *argv[])
argv += optind;
argc -= optind;
- if (argc < 2) {
- printf("ping_pong [options] <file> <num_locks>\n");
- printf(" -r do reads\n");
- printf(" -w do writes\n");
- printf(" -m use mmap\n");
- printf(" -c check locks\n");
+ if (argc < 1) {
+ usage();
exit(1);
}
fname = argv[0];
+
+ fd = open(fname, O_CREAT|O_RDWR, 0600);
+ if (fd == -1) {
+ exit(1);
+ }
+
+ if (do_brl_test) {
+ if (lock_range(fd, 0, 0, false) != 0) {
+ printf("file already locked, calling check_lock to tell us who has it locked:\n");
+ (void)check_lock(fd, 0, 0);
+ printf("Working POSIX byte range locks\n");
+ exit(0);
+ }
+
+ printf("Holding lock, press any key to continue...\n");
+ printf("You should run the same command on another node now.\n");
+ getchar();
+ printf("Good bye.\n");
+ exit(0);
+ }
+
+ if (argc < 2) {
+ usage();
+ exit(1);
+ }
+
num_locks = atoi(argv[1]);
if (num_locks <= 0) {
printf("num_locks should be > 0\n");
exit(1);
}
- fd = open(fname, O_CREAT|O_RDWR, 0600);
- if (fd == -1) exit(1);
-
ping_pong(fd, num_locks);
return 0;
--
2.5.0
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