lib-index: mail_cache_lookup_offset() - Use mail_cache_sync_reset_id()

This avoids race conditions where cache fields aren't found during cache
compression.

diff --git a/src/lib-index/mail-cache-lookup.c b/src/lib-index/mail-cache-lookup.c
index b42a2cbb40512492a05e5969640bba71c4b61130..8b49cfa052771180219897eb1c655dd53521b6d1 100644 (file)
--- a/src/lib-index/mail-cache-lookup.c
+++ b/src/lib-index/mail-cache-lookup.c
@@ -80,32 +80,31 @@ static int
 mail_cache_lookup_offset(struct mail_cache *cache, struct mail_index_view *view,
                         uint32_t seq, uint32_t *offset_r)
 {
-       uint32_t offset, reset_id;
-       int i, ret;
+       uint32_t offset, reset_id, reset_id2;
+       int ret;
 
        offset = mail_cache_lookup_cur_offset(view, seq, &reset_id);
        if (offset == 0)
                return 0;
 
-       /* reset_id must match file_seq or the offset is for a different cache
-          file. if this happens, try if reopening the cache helps. if not,
-          it was probably for an old cache file that's already lost by now. */
-       i = 0;
        while (cache->hdr->file_seq != reset_id) {
-               if (++i == 2 || reset_id < cache->hdr->file_seq)
-                       return 0;
+               /* reset_it doesn't match - sync the index/cache */
+               if ((ret = mail_cache_sync_reset_id(cache)) <= 0)
+                       return ret;
 
-               if (cache->locked) {
-                       /* we're probably compressing */
+               /* lookup again after syncing */
+               offset = mail_cache_lookup_cur_offset(view, seq, &reset_id2);
+               if (offset == 0)
                        return 0;
-               }
-
-               if (!mail_cache_need_reopen(cache))
+               if (cache->hdr->file_seq == reset_id2)
+                       break; /* match - all good */
+               if (reset_id == reset_id2) {
+                       /* reset_id didn't change after sync. This means it's
+                          pointing to an old already deleted cache file. */
                        return 0;
-               else if ((ret = mail_cache_reopen(cache)) <= 0) {
-                       /* error / corrupted */
-                       return ret;
                }
+               /* reset_id changed - try again */
+               reset_id = reset_id2;
        }
 
        *offset_r = offset;