lib-index, lib-storage: Fixed race conditions with deleting mailbox.

Now only one process can successfully finish mailbox_mark_index_deleted().

diff --git a/src/lib-index/mail-index-sync.c b/src/lib-index/mail-index-sync.c
index 42a9b1388d01997edb5eaf6398bdc1974d33e345..afea7a3e28416b49f77f0c67bff83f27820c9984 100644 (file)
--- a/src/lib-index/mail-index-sync.c
+++ b/src/lib-index/mail-index-sync.c
@@ -360,21 +360,13 @@ mail_index_sync_begin_init(struct mail_index *index,
                }
        }
 
-       if (!mail_index_need_sync(index, flags,
-                                 log_file_seq, log_file_offset)) {
+       if (!mail_index_need_sync(index, flags, log_file_seq, log_file_offset) &&
+           !index->index_deleted) {
                if (locked)
                        mail_transaction_log_sync_unlock(index->log);
                return 0;
        }
 
-       if (index->index_deleted &&
-           (flags & MAIL_INDEX_SYNC_FLAG_DELETING_INDEX) == 0) {
-               /* index is already deleted. we can't sync. */
-               if (locked)
-                       mail_transaction_log_sync_unlock(index->log);
-               return -1;
-       }
-
        if (!locked) {
                /* it looks like we have something to sync. lock the file and
                   check again. */
@@ -383,6 +375,14 @@ mail_index_sync_begin_init(struct mail_index *index,
                                                  log_file_offset);
        }
 
+       if (index->index_deleted &&
+           (flags & MAIL_INDEX_SYNC_FLAG_DELETING_INDEX) == 0) {
+               /* index is already deleted. we can't sync. */
+               if (locked)
+                       mail_transaction_log_sync_unlock(index->log);
+               return -1;
+       }
+
        hdr = &index->map->hdr;
        if (hdr->log_file_tail_offset > hdr->log_file_head_offset ||
            hdr->log_file_seq > seq ||
@@ -482,7 +482,8 @@ mail_index_sync_begin_to2(struct mail_index *index,
        ctx->ext_trans = mail_index_transaction_begin(ctx->view, trans_flags);
        ctx->ext_trans->sync_transaction = TRUE;
        ctx->ext_trans->commit_deleted_index =
-               (flags & MAIL_INDEX_SYNC_FLAG_DELETING_INDEX) != 0;
+               (flags & (MAIL_INDEX_SYNC_FLAG_DELETING_INDEX |
+                         MAIL_INDEX_SYNC_FLAG_TRY_DELETING_INDEX)) != 0;
 
        *ctx_r = ctx;
        *view_r = ctx->view;
@@ -789,10 +790,16 @@ int mail_index_sync_commit(struct mail_index_sync_ctx **_ctx)
 
        index_undeleted = ctx->ext_trans->index_undeleted;
        delete_index = index->index_delete_requested && !index_undeleted &&
-               (ctx->flags & MAIL_INDEX_SYNC_FLAG_DELETING_INDEX) != 0;
+               (ctx->flags & (MAIL_INDEX_SYNC_FLAG_DELETING_INDEX |
+                              MAIL_INDEX_SYNC_FLAG_TRY_DELETING_INDEX)) != 0;
        if (delete_index) {
                /* finish this sync by marking the index deleted */
                mail_index_set_deleted(ctx->ext_trans);
+       } else if (index->index_deleted && !index_undeleted &&
+                  (ctx->flags & MAIL_INDEX_SYNC_FLAG_TRY_DELETING_INDEX) == 0) {
+               /* another process just marked the index deleted.
+                  finish the sync, but return error. */
+               ret = -1;
        }
 
        mail_index_sync_update_mailbox_offset(ctx);

diff --git a/src/lib-index/mail-index.h b/src/lib-index/mail-index.h
index e3a336277de25b164e9a6225dff06b5635bb9065..e4ddf8dd6f35719f38c49a0b8f3d4c53ba4d1505 100644 (file)
--- a/src/lib-index/mail-index.h
+++ b/src/lib-index/mail-index.h
@@ -159,7 +159,11 @@ enum mail_index_sync_flags {
        MAIL_INDEX_SYNC_FLAG_FSYNC              = 0x10,
        /* If we see "delete index" request transaction, finish it.
           This flag also allows committing more changes to a deleted index. */
-       MAIL_INDEX_SYNC_FLAG_DELETING_INDEX     = 0x20
+       MAIL_INDEX_SYNC_FLAG_DELETING_INDEX     = 0x20,
+       /* Same as MAIL_INDEX_SYNC_FLAG_DELETING_INDEX, but finish index
+          deletion only once and fail the rest (= avoid race conditions when
+          multiple processes try to mark the index deleted) */
+       MAIL_INDEX_SYNC_FLAG_TRY_DELETING_INDEX = 0x40
 };
 
 enum mail_index_view_sync_flags {

diff --git a/src/lib-index/mail-transaction-log-file.c b/src/lib-index/mail-transaction-log-file.c
index 161d0665a63abf70bfa34a4704c5de13ff62b6db..f42b4e224f0a6dad5265ceafb24ea799c23b59bd 100644 (file)
--- a/src/lib-index/mail-transaction-log-file.c
+++ b/src/lib-index/mail-transaction-log-file.c
@@ -1284,6 +1284,7 @@ log_file_track_sync(struct mail_transaction_log_file *file,
                if (file->sync_offset < file->index_undeleted_offset)
                        break;
                file->log->index->index_deleted = TRUE;
+               file->log->index->index_delete_requested = FALSE;
                file->index_deleted_offset = file->sync_offset + trans_size;
                break;
        case MAIL_TRANSACTION_INDEX_UNDELETED:

diff --git a/src/lib-storage/index/index-sync.c b/src/lib-storage/index/index-sync.c
index 49a44b0b8d0bcb9447e3d4e62b4d23040def7880..53c1fd27799864eb2aba394d99b603a7449cb251 100644 (file)
--- a/src/lib-storage/index/index-sync.c
+++ b/src/lib-storage/index/index-sync.c
@@ -17,8 +17,11 @@ enum mail_index_sync_flags index_storage_get_sync_flags(struct mailbox *box)
 
        if ((box->flags & MAILBOX_FLAG_DROP_RECENT) != 0)
                sync_flags |= MAIL_INDEX_SYNC_FLAG_DROP_RECENT;
-       if (box->deleting)
-               sync_flags |= MAIL_INDEX_SYNC_FLAG_DELETING_INDEX;
+       if (box->deleting) {
+               sync_flags |= box->delete_sync_check ?
+                       MAIL_INDEX_SYNC_FLAG_TRY_DELETING_INDEX :
+                       MAIL_INDEX_SYNC_FLAG_DELETING_INDEX;
+       }
        return sync_flags;
 }
 

diff --git a/src/lib-storage/mail-storage-private.h b/src/lib-storage/mail-storage-private.h
index e30ef466fe6229f48643d52858e6aea3d725ef8e..a10e6c607221c82f02db5a11b4a1c6246542e004 100644 (file)
--- a/src/lib-storage/mail-storage-private.h
+++ b/src/lib-storage/mail-storage-private.h
@@ -332,6 +332,8 @@ struct mailbox {
        unsigned int creating:1;
        /* Mailbox is being deleted */
        unsigned int deleting:1;
+       /* Don't use MAIL_INDEX_SYNC_FLAG_DELETING_INDEX for sync flag */
+       unsigned int delete_sync_check:1;
        /* Delete mailbox only if it's empty */
        unsigned int deleting_must_be_empty:1;
        /* The backend wants to skip checking if there are 0 messages before

diff --git a/src/lib-storage/mail-storage.c b/src/lib-storage/mail-storage.c
index e8ea62a1d1e3f3074ac1975dedd44502ee457801..1f2c4ccc7acaa95258512fb703a8b51d7fdc5d86 100644 (file)
--- a/src/lib-storage/mail-storage.c
+++ b/src/lib-storage/mail-storage.c
@@ -1319,7 +1319,10 @@ int mailbox_mark_index_deleted(struct mailbox *box, bool del)
        /* sync the mailbox. this finishes the index deletion and it can
           succeed only for a single session. we do it here, so the rest of
           the deletion code doesn't have to worry about race conditions. */
-       if (mailbox_sync(box, MAILBOX_SYNC_FLAG_FULL_READ) < 0)
+       box->delete_sync_check = TRUE;
+       ret = mailbox_sync(box, MAILBOX_SYNC_FLAG_FULL_READ);
+       box->delete_sync_check = FALSE;
+       if (ret < 0)
                return -1;
 
        box->marked_deleted = del;