From: Stephan Bosch <stephan.bosch@open-xchange.com>
Date: Mon, 20 Sep 2021 00:45:23 +0000 (+0200)
Subject: lib: file-lock - Adjust API to allow EDEADLK to be used by application.
X-Git-Tag: 2.3.17~63
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=4c1cf82d614a4c390a336a6f4a6533cf5cdd65af;p=thirdparty%2Fdovecot%2Fcore.git

lib: file-lock - Adjust API to allow EDEADLK to be used by application.

It always caused a Dovecot panic before when returned from kernel.
---

diff --git a/src/lib/file-lock.c b/src/lib/file-lock.c
index 38ad23db09..f17beea3bc 100644
--- a/src/lib/file-lock.c
+++ b/src/lib/file-lock.c
@@ -220,7 +220,7 @@ static int file_lock_do(int fd, const char *path, int lock_type,
 		}
 		*error_r = t_strdup_printf("fcntl(%s, %s, %s) locking failed: %m",
 			path, lock_type_str, timeout_secs == 0 ? "F_SETLK" : "F_SETLKW");
-		if (errno == EDEADLK) {
+		if (errno == EDEADLK && !set->allow_deadlock) {
 			i_panic("%s%s", *error_r,
 				file_lock_find(fd, set->lock_method,
 					       lock_type));
@@ -275,7 +275,7 @@ static int file_lock_do(int fd, const char *path, int lock_type,
 		}
 		*error_r = t_strdup_printf("flock(%s, %s) failed: %m",
 					   path, lock_type_str);
-		if (errno == EDEADLK) {
+		if (errno == EDEADLK && !set->allow_deadlock) {
 			i_panic("%s%s", *error_r,
 				file_lock_find(fd, set->lock_method,
 					       lock_type));
diff --git a/src/lib/file-lock.h b/src/lib/file-lock.h
index 525c1d2be8..0939adc69e 100644
--- a/src/lib/file-lock.h
+++ b/src/lib/file-lock.h
@@ -25,6 +25,9 @@ struct file_lock_settings {
 	   processes are already waiting on the lock. This can be useful for
 	   files that are only created to exist as lock files. */
 	bool close_on_free:1;
+	/* Do not panic when the kernel returns EDEADLK while acquiring the
+	   lock. */
+	bool allow_deadlock:1;
 };
 
 /* Parse lock method from given string. Returns TRUE if ok,