cyrus-imapd/cyrus-imapd-2.1.3-flock.patch
Michal Hlavinka eaf31cffbd - updated to 2.4.6
- "autocreate" and "autosieve" features were removed
2011-02-10 14:56:53 +01:00

79 lines
2.5 KiB
Diff

diff -up cyrus-imapd-2.4.6/lib/lock_flock.c.flock cyrus-imapd-2.4.6/lib/lock_flock.c
--- cyrus-imapd-2.4.6/lib/lock_flock.c.flock 2010-12-20 14:15:49.000000000 +0100
+++ cyrus-imapd-2.4.6/lib/lock_flock.c 2011-02-10 12:56:45.262786102 +0100
@@ -52,6 +52,10 @@
#endif
#include "cyr_lock.h"
+#include <syslog.h>
+
+/* Locking timeout parameter */
+#define MAXTIME 99
const char *lock_method_desc = "flock";
@@ -68,6 +72,18 @@ const char *lock_method_desc = "flock";
* 'failaction' is provided, it is filled in with a pointer to a fixed
* string naming the action that failed.
*
+ * Modified by jwade 4/16/2002 to work around seen file locking problem
+ * Added locking timeout parameter to allow processes that are
+ * waiting for a lock to eventually time out
+ *
+ * Calls flock() in non-blocking fashion and then retries until a
+ * maximum delay is reached or the lock succeeds.
+ *
+ * As written, uses a quadratic backoff on retries with MAXTIME being
+ * the longest interval delay. Total delay time is the sum of the squares
+ * of all integers whose square is less than MAXTIME. In the case of
+ * MAXTIME = 99 this is 0+1+4+9+16+25+36+49+64+81= 285 Seconds
+ * This time is arbitrary and can be adjusted
*/
int lock_reopen(fd, filename, sbuf, failaction)
int fd;
@@ -78,17 +94,29 @@ const char **failaction;
int r;
struct stat sbuffile, sbufspare;
int newfd;
+ int delay=0, i=0;
if (!sbuf) sbuf = &sbufspare;
- for (;;) {
- r = flock(fd, LOCK_EX);
+ for(i=0,delay=0;;) {
+ r = flock(fd, LOCK_EX|LOCK_NB);
if (r == -1) {
- if (errno == EINTR) continue;
- if (failaction) *failaction = "locking";
+ if (errno == EINTR) {
+ continue;
+ }
+ else if ((errno == EWOULDBLOCK) && (delay < MAXTIME)) {
+ syslog(LOG_DEBUG, "lock: reopen-blocked sleeping for %d on interval %d (%d, %s)" , delay, i, fd, filename);
+ sleep(delay);
+ i++;
+ delay = i*i;
+ continue;
+ }
+ if (failaction) {
+ if (delay >= MAXTIME) *failaction = "locking_timeout";
+ else *failaction = "locking";
+ }
return -1;
}
-
fstat(fd, sbuf);
r = stat(filename, &sbuffile);
if (r == -1) {
@@ -96,9 +124,7 @@ const char **failaction;
flock(fd, LOCK_UN);
return -1;
}
-
if (sbuf->st_ino == sbuffile.st_ino) return 0;
-
newfd = open(filename, O_RDWR);
if (newfd == -1) {
if (failaction) *failaction = "opening";