Maildir saving: Fixed race condition bugs in uidlist handling, causing files to be...

--HG--
branch : HEAD

diff --git a/src/lib-storage/index/maildir/maildir-uidlist.c b/src/lib-storage/index/maildir/maildir-uidlist.c
index ad324bc8753f06cb09170353e2162d83963cfacd..0e5d2284a4bc6ab046b89c2691fd0841627ac3c8 100644 (file)
--- a/src/lib-storage/index/maildir/maildir-uidlist.c
+++ b/src/lib-storage/index/maildir/maildir-uidlist.c
@@ -93,6 +93,7 @@ struct maildir_uidlist {
        unsigned int initial_hdr_read:1;
        unsigned int initial_sync:1;
        unsigned int retry_rewind:1;
+       unsigned int locked_refresh:1;
 };
 
 struct maildir_uidlist_sync_ctx {
@@ -173,6 +174,7 @@ static int maildir_uidlist_lock_timeout(struct maildir_uidlist *uidlist,
        }
 
        uidlist->lock_count++;
+       uidlist->locked_refresh = FALSE;
 
        if (refresh) {
                /* make sure we have the latest changes before
@@ -214,6 +216,7 @@ void maildir_uidlist_unlock(struct maildir_uidlist *uidlist)
        if (--uidlist->lock_count > 0)
                return;
 
+       uidlist->locked_refresh = FALSE;
        (void)file_dotlock_delete(&uidlist->dotlock);
 }
 
@@ -815,6 +818,8 @@ int maildir_uidlist_refresh(struct maildir_uidlist *uidlist)
        if (ret >= 0) {
                uidlist->initial_read = TRUE;
                uidlist->initial_hdr_read = TRUE;
+               if (UIDLIST_IS_LOCKED(uidlist))
+                       uidlist->locked_refresh = TRUE;
        }
         return ret;
 }
@@ -1022,7 +1027,10 @@ maildir_uidlist_set_ext_real(struct maildir_uidlist *uidlist, uint32_t uid,
        rec->extensions = p_malloc(uidlist->record_pool, buf->used);
        memcpy(rec->extensions, buf->data, buf->used);
 
-       uidlist->recreate = TRUE;
+       if (rec->uid != (uint32_t)-1) {
+               /* message already exists in uidlist, need to recreate it */
+               uidlist->recreate = TRUE;
+       }
 }
 
 void maildir_uidlist_set_ext(struct maildir_uidlist *uidlist, uint32_t uid,
@@ -1213,8 +1221,10 @@ static bool maildir_uidlist_want_compress(struct maildir_uidlist_sync_ctx *ctx)
 {
        unsigned int min_rewrite_count;
 
-       if (!ctx->uidlist->initial_read)
+       if (!ctx->uidlist->locked_refresh)
                return FALSE;
+       if (ctx->uidlist->recreate)
+               return TRUE;
 
        min_rewrite_count =
                (ctx->uidlist->read_records_count + ctx->new_files_count) *
@@ -1226,12 +1236,10 @@ static bool maildir_uidlist_want_recreate(struct maildir_uidlist_sync_ctx *ctx)
 {
        struct maildir_uidlist *uidlist = ctx->uidlist;
 
-       if (uidlist->recreate ||
-           ctx->finish_change_counter != uidlist->change_counter)
-               return TRUE;
-
-       if (!uidlist->initial_read)
+       if (!uidlist->locked_refresh)
                return FALSE;
+       if (ctx->finish_change_counter != uidlist->change_counter)
+               return TRUE;
 
        if (uidlist->fd == -1 || uidlist->version != UIDLIST_VERSION)
                return TRUE;
@@ -1291,7 +1299,7 @@ static int maildir_uidlist_sync_update(struct maildir_uidlist_sync_ctx *ctx)
        if ((uoff_t)st.st_size != file_size) {
                i_warning("%s: file size changed unexpectedly after write",
                          uidlist->path);
-       } else {
+       } else if (uidlist->locked_refresh) {
                uidlist->fd_size = st.st_size;
                uidlist->last_read_offset = st.st_size;
                maildir_uidlist_update_hdr(uidlist, &st);
@@ -1530,6 +1538,7 @@ void maildir_uidlist_sync_remove(struct maildir_uidlist_sync_ctx *ctx,
        unsigned int idx;
 
        i_assert(ctx->partial);
+       i_assert(ctx->uidlist->locked_refresh);
 
        rec = hash_table_lookup(ctx->uidlist->files, filename);
        i_assert(rec != NULL);
@@ -1673,8 +1682,7 @@ void maildir_uidlist_sync_finish(struct maildir_uidlist_sync_ctx *ctx)
        /* mbox=NULL means we're coming from dbox rebuilding code.
           the dbox is already locked, so allow uidlist recreation */
        i_assert(ctx->locked || !ctx->changed || ctx->uidlist->mbox == NULL);
-       if ((ctx->changed || ctx->uidlist->recreate ||
-            maildir_uidlist_want_compress(ctx)) &&
+       if ((ctx->changed || maildir_uidlist_want_compress(ctx)) &&
            !ctx->failed && (ctx->locked || ctx->uidlist->mbox == NULL)) {
                T_BEGIN {
                        if (maildir_uidlist_sync_update(ctx) < 0)