lib-index: mail_transaction_log_file_sync(): Don't mix I/O errors and corruption

diff --git a/src/lib-index/mail-transaction-log-file.c b/src/lib-index/mail-transaction-log-file.c
index 92c7496ade8dac8b4400b1f04339c84a7e0647f8..5acb62165c7b80edafd5f5f06df20e1968ae50ba 100644 (file)
--- a/src/lib-index/mail-transaction-log-file.c
+++ b/src/lib-index/mail-transaction-log-file.c
@@ -17,7 +17,8 @@
 #define LOG_NEW_DOTLOCK_SUFFIX ".newlock"
 
 static int
-mail_transaction_log_file_sync(struct mail_transaction_log_file *file);
+mail_transaction_log_file_sync(struct mail_transaction_log_file *file,
+                              bool *retry_r);
 
 static void
 log_file_set_syscall_error(struct mail_transaction_log_file *file,
@@ -189,6 +190,7 @@ static void
 mail_transaction_log_file_add_to_list(struct mail_transaction_log_file *file)
 {
        struct mail_transaction_log_file **p;
+       bool retry;
 
        file->sync_offset = file->hdr.hdr_size;
        file->sync_highest_modseq = file->hdr.initial_modseq;
@@ -207,7 +209,7 @@ mail_transaction_log_file_add_to_list(struct mail_transaction_log_file *file)
        if (file->buffer != NULL) {
                /* if we read any unfinished data, make sure the buffer gets
                   truncated. */
-               (void)mail_transaction_log_file_sync(file);
+               (void)mail_transaction_log_file_sync(file, &retry);
                buffer_set_used_size(file->buffer,
                                     file->sync_offset - file->buffer_offset);
        }
@@ -1356,7 +1358,8 @@ log_file_track_sync(struct mail_transaction_log_file *file,
 }
 
 static int
-mail_transaction_log_file_sync(struct mail_transaction_log_file *file)
+mail_transaction_log_file_sync(struct mail_transaction_log_file *file,
+                              bool *retry_r)
 {
         const struct mail_transaction_header *hdr;
        const void *data;
@@ -1367,6 +1370,8 @@ mail_transaction_log_file_sync(struct mail_transaction_log_file *file)
 
        i_assert(file->sync_offset >= file->buffer_offset);
 
+       *retry_r = FALSE;
+
        data = buffer_get_data(file->buffer, &size);
        if (file->buffer_offset + size < file->sync_offset) {
                mail_transaction_log_file_set_corrupted(file,
@@ -1374,7 +1379,7 @@ mail_transaction_log_file_sync(struct mail_transaction_log_file *file)
                        file->buffer_offset + (uoff_t)size, file->sync_offset);
                /* fix the sync_offset to avoid crashes later on */
                file->sync_offset = file->buffer_offset + size;
-               return -1;
+               return 0;
        }
        while (file->sync_offset - file->buffer_offset + sizeof(*hdr) <= size) {
                hdr = CONST_PTR_OFFSET(data, file->sync_offset -
@@ -1387,7 +1392,7 @@ mail_transaction_log_file_sync(struct mail_transaction_log_file *file)
                if (trans_size < sizeof(*hdr)) {
                        mail_transaction_log_file_set_corrupted(file,
                                "hdr.size too small (%u)", trans_size);
-                       return -1;
+                       return 0;
                }
 
                if (file->sync_offset - file->buffer_offset + trans_size > size)
@@ -1396,7 +1401,7 @@ mail_transaction_log_file_sync(struct mail_transaction_log_file *file)
                /* transaction has been fully written */
                if ((ret = log_file_track_sync(file, hdr, trans_size)) <= 0) {
                        if (ret < 0)
-                               return -1;
+                               return 0;
                        break;
                }
 
@@ -1419,6 +1424,7 @@ mail_transaction_log_file_sync(struct mail_transaction_log_file *file)
                }
                if ((uoff_t)st.st_size != file->last_size) {
                        file->last_size = st.st_size;
+                       *retry_r = TRUE;
                        return 0;
                }
        }
@@ -1431,7 +1437,7 @@ mail_transaction_log_file_sync(struct mail_transaction_log_file *file)
                if (file->locked) {
                        mail_transaction_log_file_set_corrupted(file,
                                "Unexpected garbage at EOF");
-                       return -1;
+                       return 0;
                }
                /* The size field will be updated soon */
                mail_index_flush_read_cache(file->log->index, file->filepath,
@@ -1445,7 +1451,7 @@ mail_transaction_log_file_sync(struct mail_transaction_log_file *file)
                        "Invalid transaction log size "
                        "(%"PRIuUOFF_T" vs %u): %s", file->sync_offset,
                        file->log->head->hdr.prev_file_offset, file->filepath);
-               return -1;
+               return 0;
        }
 
        return 1;
@@ -1544,6 +1550,7 @@ static int
 mail_transaction_log_file_read(struct mail_transaction_log_file *file,
                               uoff_t start_offset, bool nfs_flush)
 {
+       bool retry;
        int ret;
 
        i_assert(file->mmap_base == NULL);
@@ -1579,11 +1586,10 @@ mail_transaction_log_file_read(struct mail_transaction_log_file *file,
                 mail_transaction_log_file_need_nfs_flush(file)) {
                /* we didn't read enough data. flush and try again. */
                return mail_transaction_log_file_read(file, start_offset, TRUE);
-       } else if ((ret = mail_transaction_log_file_sync(file)) <= 0) {
-               i_assert(ret != 0); /* ret=0 happens only with mmap */
-       } else {
-               i_assert(file->sync_offset >= file->buffer_offset);
+       } else if ((ret = mail_transaction_log_file_sync(file, &retry)) == 0) {
+               i_assert(!retry); /* retry happens only with mmap */
        }
+       i_assert(file->sync_offset >= file->buffer_offset);
        buffer_set_used_size(file->buffer,
                             file->sync_offset - file->buffer_offset);
        return ret;
@@ -1665,6 +1671,7 @@ mail_transaction_log_file_map_mmap(struct mail_transaction_log_file *file,
                                   uoff_t start_offset)
 {
        struct stat st;
+       bool retry;
        int ret;
 
        /* we are going to mmap() this file, but it's not necessarily
@@ -1688,10 +1695,9 @@ mail_transaction_log_file_map_mmap(struct mail_transaction_log_file *file,
        if (file->buffer != NULL && file->buffer_offset <= start_offset &&
            (uoff_t)st.st_size == file->buffer_offset + file->buffer->used) {
                /* we already have the whole file mapped */
-               if ((ret = mail_transaction_log_file_sync(file)) < 0)
-                       return 0;
-               if (ret > 0)
-                       return 1;
+               if ((ret = mail_transaction_log_file_sync(file, &retry)) != 0 ||
+                   !retry)
+                       return ret;
                /* size changed, re-mmap */
        }
 
@@ -1707,11 +1713,10 @@ mail_transaction_log_file_map_mmap(struct mail_transaction_log_file *file,
 
                if (mail_transaction_log_file_mmap(file) < 0)
                        return -1;
-               if ((ret = mail_transaction_log_file_sync(file)) < 0)
-                       return 0;
-       } while (ret == 0);
+               ret = mail_transaction_log_file_sync(file, &retry);
+       } while (retry);
 
-       return 1;
+       return ret;
 }
 
 int mail_transaction_log_file_map(struct mail_transaction_log_file *file,