dovecot-1.2: Mail cache compression: If we can't get lock immedi...

[dovecot at dovecot.org]

details:   http://hg.dovecot.org/dovecot-1.2/rev/2db48458d73b
changeset: 8188:2db48458d73b
user:      Timo Sirainen <tss at iki.fi>
date:      Thu Sep 11 17:01:32 2008 +0300
description:
Mail cache compression: If we can't get lock immediately, do it later.

diffstat:

3 files changed, 26 insertions(+), 8 deletions(-)
src/lib-index/mail-cache-compress.c |    7 ++++---
src/lib-index/mail-cache-private.h  |    1 +
src/lib-index/mail-cache.c          |   26 +++++++++++++++++++++-----

diffs (106 lines):

diff -r f1203dce2d8c -r 2db48458d73b src/lib-index/mail-cache-compress.c
--- a/src/lib-index/mail-cache-compress.c	Thu Sep 11 16:52:47 2008 +0300
+++ b/src/lib-index/mail-cache-compress.c	Thu Sep 11 17:01:32 2008 +0300
@@ -361,11 +361,12 @@ static int mail_cache_compress_locked(st
 
 	old_mask = umask(cache->index->mode ^ 0666);
 	fd = file_dotlock_open(&cache->dotlock_settings, cache->filepath,
-			       0, &dotlock);
+			       DOTLOCK_CREATE_FLAG_NONBLOCK, &dotlock);
 	umask(old_mask);
 
 	if (fd == -1) {
-		mail_cache_set_syscall_error(cache, "file_dotlock_open()");
+		if (errno != EAGAIN)
+			mail_cache_set_syscall_error(cache, "file_dotlock_open()");
 		return -1;
 	}
 
@@ -467,7 +468,7 @@ int mail_cache_compress(struct mail_cach
 						    FALSE);
 		}
 	} else {
-		switch (mail_cache_lock(cache, FALSE)) {
+		switch (mail_cache_try_lock(cache)) {
 		case -1:
 			return -1;
 		case 0:
diff -r f1203dce2d8c -r 2db48458d73b src/lib-index/mail-cache-private.h
--- a/src/lib-index/mail-cache-private.h	Thu Sep 11 16:52:47 2008 +0300
+++ b/src/lib-index/mail-cache-private.h	Thu Sep 11 17:01:32 2008 +0300
@@ -224,6 +224,7 @@ int mail_cache_open_and_verify(struct ma
 /* Explicitly lock the cache file. Returns -1 if error / timed out,
    1 if ok, 0 if cache is broken/doesn't exist */
 int mail_cache_lock(struct mail_cache *cache, bool require_same_reset_id);
+int mail_cache_try_lock(struct mail_cache *cache);
 /* Returns -1 if cache is / just got corrupted, 0 if ok. */
 int mail_cache_unlock(struct mail_cache *cache);
 
diff -r f1203dce2d8c -r 2db48458d73b src/lib-index/mail-cache.c
--- a/src/lib-index/mail-cache.c	Thu Sep 11 16:52:47 2008 +0300
+++ b/src/lib-index/mail-cache.c	Thu Sep 11 17:01:32 2008 +0300
@@ -460,7 +460,7 @@ void mail_cache_free(struct mail_cache *
 	i_free(cache);
 }
 
-static int mail_cache_lock_file(struct mail_cache *cache)
+static int mail_cache_lock_file(struct mail_cache *cache, bool nonblock)
 {
 	int ret;
 
@@ -468,12 +468,16 @@ static int mail_cache_lock_file(struct m
 		i_assert(cache->file_lock == NULL);
 		ret = mail_index_lock_fd(cache->index, cache->filepath,
 					 cache->fd, F_WRLCK,
-					 MAIL_CACHE_LOCK_TIMEOUT,
+					 nonblock ? 0 : MAIL_CACHE_LOCK_TIMEOUT,
 					 &cache->file_lock);
 	} else {
+		enum dotlock_create_flags flags =
+			nonblock ? DOTLOCK_CREATE_FLAG_NONBLOCK : 0;
+
 		i_assert(cache->dotlock == NULL);
 		ret = file_dotlock_create(&cache->dotlock_settings,
-					  cache->filepath, 0, &cache->dotlock);
+					  cache->filepath, flags,
+					  &cache->dotlock);
 		if (ret <= 0) {
 			mail_cache_set_syscall_error(cache,
 						     "file_dotlock_create()");
@@ -496,7 +500,9 @@ static void mail_cache_unlock_file(struc
 		(void)file_dotlock_delete(&cache->dotlock);
 }
 
-int mail_cache_lock(struct mail_cache *cache, bool require_same_reset_id)
+static int
+mail_cache_lock_full(struct mail_cache *cache, bool require_same_reset_id,
+		     bool nonblock)
 {
 	const struct mail_index_ext *ext;
 	struct mail_index_view *iview;
@@ -538,7 +544,7 @@ int mail_cache_lock(struct mail_cache *c
 				break;
 		}
 
-		if ((ret = mail_cache_lock_file(cache)) <= 0) {
+		if ((ret = mail_cache_lock_file(cache, nonblock)) <= 0) {
 			ret = -1;
 			break;
 		}
@@ -571,6 +577,16 @@ int mail_cache_lock(struct mail_cache *c
 
 	i_assert((ret <= 0 && !cache->locked) || (ret > 0 && cache->locked));
 	return ret;
+}
+
+int mail_cache_lock(struct mail_cache *cache, bool require_same_reset_id)
+{
+	return mail_cache_lock_full(cache, require_same_reset_id, FALSE);
+}
+
+int mail_cache_try_lock(struct mail_cache *cache)
+{
+	return mail_cache_lock_full(cache, FALSE, TRUE);
 }
 
 static void mail_cache_update_need_compress(struct mail_cache *cache)