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locks: Protected racy (read) access of ext_list

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Change-Id: Ibf639695ebd99c11c6960c9be82c0cee71b50744
BUG: 905864
Signed-off-by: Krishnan Parthasarathi <kparthas@redhat.com>
Reviewed-on: http://review.gluster.org/4458
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Amar Tumballi <amarts@redhat.com>
Reviewed-by: Anand Avati <avati@redhat.com>
This commit is contained in:
Krishnan Parthasarathi 2013-01-31 10:29:20 +05:30 committed by Anand Avati
parent 67d0e72b16
commit 6b262d2094
3 changed files with 129 additions and 10 deletions
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82
tests/bugs/bug-905864.c Normal file
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@ -0,0 +1,82 @@
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <pthread.h>
pthread_t th[5] = {0};
void
flock_init (struct flock *f, short int type, off_t start, off_t len)
{
f->l_type = type;
f->l_start = start;
f->l_len = len;
}
int
flock_range_in_steps (int fd, int is_set, short l_type,
int start, int end, int step)
{
int ret = 0;
int i = 0;
struct flock f = {0,};
for (i = start; i+step < end; i += step) {
flock_init (&f, l_type, i, step);
ret = fcntl (fd, (is_set)? F_SETLKW:F_GETLK, &f);
if (ret) {
perror ("fcntl");
goto out;
}
}
out:
return ret;
}
void *
random_locker (void *arg)
{
int fd = *(int *)arg;
int i = 0;
int is_set = 0;
/* use thread id to choose GETLK or SETLK operation*/
is_set = pthread_self () % 2;
(void)flock_range_in_steps (fd, is_set, F_WRLCK, 0, 400, 1);
return NULL;
}
int main (int argc, char **argv)
{
int fd = -1;
int ret = 1;
int i = 0;
char *fname = NULL;
if (argc < 2)
goto out;
fname = argv[1];
fd = open (fname, O_RDWR);
if (fd == -1) {
perror ("open");
goto out;
}
ret = flock_range_in_steps (fd, 1, F_WRLCK, 0, 2000, 2);
for (i = 0; i < 5; i++) {
pthread_create (&th[i], NULL, random_locker, (void *) &fd);
}
ret = flock_range_in_steps (fd, 1, F_WRLCK, 0, 2000, 2);
for (i = 0; i < 5; i++) {
pthread_join (th[i], NULL);
}
out:
if (fd != -1)
close (fd);
return ret;
}

29
tests/bugs/bug-905864.t Normal file
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@ -0,0 +1,29 @@
#!/bin/bash
. $(dirname $0)/../include.rc
cleanup;
## Start and create a volume
TEST glusterd;
TEST pidof glusterd;
TEST $CLI volume info;
TEST $CLI volume create $V0 replica 2 stripe 2 $H0:$B0/${V0}{1,2,3,4,5,6,7,8};
TEST $CLI volume start $V0;
TEST glusterfs --entry-timeout=0 --attribute-timeout=0 -s $H0 --volfile-id $V0 $M0;
TEST glusterfs --entry-timeout=0 --attribute-timeout=0 -s $H0 --volfile-id $V0 $M1;
TEST touch $M0/file1;
#following C program tries open up race(s) if any, in F_GETLK/F_SETLKW codepaths
#of locks xlator
gcc -lpthread -g3 $(dirname $0)/bug-905864.c -o $(dirname $0)/bug-905864
$(dirname $0)/bug-905864 $M0/file1 &
$(dirname $0)/bug-905864 $M1/file1;
wait
rm -f $(dirname $0)/bug-905864
cleanup

28
xlators/features/locks/src/common.c
View File

@ -718,22 +718,30 @@ static posix_lock_t *
first_conflicting_overlap (pl_inode_t *pl_inode, posix_lock_t *lock)
{
posix_lock_t *l = NULL;
posix_lock_t *conf = NULL;
list_for_each_entry (l, &pl_inode->ext_list, list) {
if (l->blocked)
continue;
if (locks_overlap (l, lock)) {
if (same_owner (l, lock))
pthread_mutex_lock (&pl_inode->mutex);
{
list_for_each_entry (l, &pl_inode->ext_list, list) {
if (l->blocked)
continue;
if ((l->fl_type == F_WRLCK) ||
(lock->fl_type == F_WRLCK))
return l;
if (locks_overlap (l, lock)) {
if (same_owner (l, lock))
continue;
if ((l->fl_type == F_WRLCK) ||
(lock->fl_type == F_WRLCK)) {
conf = l;
goto unlock;
}
}
}
}
unlock:
pthread_mutex_unlock (&pl_inode->mutex);
return NULL;
return conf;
}
/*