flock is not supported on nfs. fcntl is at least supported on newer
(v3 and above) nfs.
Signed-off-by: Serge Hallyn <serge.hal...@ubuntu.com>
---
src/lxc/lxccontainer.c | 22 +++++++++++++++++-----
src/lxc/lxclock.c | 16 ++++++++++++++--
2 files changed, 31 insertions(+), 7 deletions(-)
diff --git a/src/lxc/lxccontainer.c b/src/lxc/lxccontainer.c
index 2edf749..cf5252b 100644
--- a/src/lxc/lxccontainer.c
+++ b/src/lxc/lxccontainer.c
@@ -23,6 +23,7 @@
#include <sys/types.h>
#include <sys/wait.h>
#include <errno.h>
+#include <fcntl.h>
#include <sched.h>
#include "config.h"
#include "lxc.h"
@@ -39,7 +40,6 @@
#include <lxc/utils.h>
#include <lxc/monitor.h>
#include <sched.h>
-#include <fcntl.h>
#include <arpa/inet.h>
#include <ifaddrs.h>
@@ -66,6 +66,8 @@ int ongoing_create(struct lxc_container *c)
int len = strlen(c->config_path) + strlen(c->name) + 10;
char *path = alloca(len);
int fd, ret;
+ struct flock lk;
+
ret = snprintf(path, len, "%s/%s/partial", c->config_path, c->name);
if (ret < 0 || ret >= len) {
ERROR("Error writing partial pathname");
@@ -82,8 +84,12 @@ int ongoing_create(struct lxc_container *c)
process_unlock();
return 0;
}
- if ((ret = flock(fd, LOCK_EX | LOCK_NB)) == -1 &&
- errno == EWOULDBLOCK) {
+ lk.l_type = F_WRLCK;
+ lk.l_whence = SEEK_SET;
+ lk.l_start = 0;
+ lk.l_len = 0;
+ lk.l_pid = -1;
+ if (fcntl(fd, F_GETLK, &lk) == 0 && lk.l_pid != -1) {
// create is still ongoing
close(fd);
process_unlock();
@@ -101,6 +107,8 @@ int create_partial(struct lxc_container *c)
int len = strlen(c->config_path) + strlen(c->name) + 10;
char *path = alloca(len);
int fd, ret;
+ struct flock lk;
+
ret = snprintf(path, len, "%s/%s/partial", c->config_path, c->name);
if (ret < 0 || ret >= len) {
ERROR("Error writing partial pathname");
@@ -108,12 +116,16 @@ int create_partial(struct lxc_container *c)
}
if (process_lock())
return -1;
- if ((fd=open(path, O_CREAT | O_EXCL, 0755)) < 0) {
+ if ((fd=open(path, O_RDWR | O_CREAT | O_EXCL, 0755)) < 0) {
SYSERROR("Erorr creating partial file");
process_unlock();
return -1;
}
- if (flock(fd, LOCK_EX) < 0) {
+ lk.l_type = F_WRLCK;
+ lk.l_whence = SEEK_SET;
+ lk.l_start = 0;
+ lk.l_len = 0;
+ if (fcntl(fd, F_SETLKW, &lk) < 0) {
SYSERROR("Error locking partial file %s", path);
close(fd);
process_unlock();
diff --git a/src/lxc/lxclock.c b/src/lxc/lxclock.c
index 4bbe873..d004cc5 100644
--- a/src/lxc/lxclock.c
+++ b/src/lxc/lxclock.c
@@ -23,6 +23,7 @@
#include <stdio.h>
#include <errno.h>
#include <unistd.h>
+#include <fcntl.h>
#include <lxc/utils.h>
#include <lxc/log.h>
#include <lxc/lxccontainer.h>
@@ -111,6 +112,7 @@ out:
int lxclock(struct lxc_lock *l, int timeout)
{
int ret = -1, saved_errno = errno;
+ struct flock lk;
switch(l->type) {
case LXC_LOCK_ANON_SEM:
@@ -152,7 +154,11 @@ int lxclock(struct lxc_lock *l, int timeout)
goto out;
}
}
- ret = flock(l->u.f.fd, LOCK_EX);
+ lk.l_type = F_WRLCK;
+ lk.l_whence = SEEK_SET;
+ lk.l_start = 0;
+ lk.l_len = 0;
+ ret = fcntl(l->u.f.fd, F_SETLKW, &lk);
process_unlock();
if (ret == -1)
saved_errno = errno;
@@ -167,6 +173,7 @@ out:
int lxcunlock(struct lxc_lock *l)
{
int ret = 0, saved_errno = errno;
+ struct flock lk;
switch(l->type) {
case LXC_LOCK_ANON_SEM:
@@ -179,7 +186,12 @@ int lxcunlock(struct lxc_lock *l)
case LXC_LOCK_FLOCK:
process_lock();
if (l->u.f.fd != -1) {
- if ((ret = flock(l->u.f.fd, LOCK_UN)) < 0)
+ lk.l_type = F_UNLCK;
+ lk.l_whence = SEEK_SET;
+ lk.l_start = 0;
+ lk.l_len = 0;
+ ret = fcntl(l->u.f.fd, F_SETLK, &lk);
+ if (ret < 0)
saved_errno = errno;
close(l->u.f.fd);
l->u.f.fd = -1;
--
1.7.9.5
------------------------------------------------------------------------------
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