From: Timo Sirainen <tss@iki.fi>
Date: Sun, 20 Jun 2004 09:13:14 +0000 (+0300)
Subject: Several fixes and cleanups to cache file code, still badly broken
X-Git-Tag: 1.1.alpha1~3905
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=56f45b3f3ae20e5c933701f4657dda5ef1916855;p=thirdparty%2Fdovecot%2Fcore.git

Several fixes and cleanups to cache file code, still badly broken

--HG--
branch : HEAD
---

diff --git a/src/lib-index/mail-cache-lookup.c b/src/lib-index/mail-cache-lookup.c
index a66f281a63..628f98b44d 100644
--- a/src/lib-index/mail-cache-lookup.c
+++ b/src/lib-index/mail-cache-lookup.c
@@ -5,6 +5,8 @@
 #include "byteorder.h"
 #include "mail-cache-private.h"
 
+#define CACHE_PREFETCH 1024
+
 const char *
 mail_cache_get_header_fields_str(struct mail_cache *cache, unsigned int idx)
 {
@@ -16,7 +18,7 @@ mail_cache_get_header_fields_str(struct mail_cache *cache, unsigned int idx)
 	if (offset == 0)
 		return NULL;
 
-	if (mail_cache_mmap_update(cache, offset, 1024) < 0)
+	if (mail_cache_mmap_update(cache, offset, CACHE_PREFETCH) < 0)
 		return NULL;
 
 	if (offset + sizeof(data_size) > cache->mmap_length) {
@@ -36,8 +38,10 @@ mail_cache_get_header_fields_str(struct mail_cache *cache, unsigned int idx)
 		return NULL;
 	}
 
-	if (mail_cache_mmap_update(cache, offset, data_size) < 0)
-		return NULL;
+	if (data_size + sizeof(data_size) > CACHE_PREFETCH) {
+		if (mail_cache_mmap_update(cache, offset, data_size) < 0)
+			return NULL;
+	}
 
 	if (offset + data_size > cache->mmap_length) {
 		mail_cache_set_corrupted(cache, "Header %u points outside file",
@@ -109,7 +113,6 @@ struct mail_cache_record *
 mail_cache_get_record(struct mail_cache *cache, uint32_t offset,
 		      int index_offset)
 {
-#define CACHE_PREFETCH 1024
 	struct mail_cache_record *cache_rec;
 	size_t size;
 
@@ -164,15 +167,23 @@ mail_cache_lookup(struct mail_cache_view *view, uint32_t seq,
 		  enum mail_cache_field fields)
 {
 	const struct mail_index_record *rec;
+	struct mail_index_map *map;
 
 	if (mail_cache_transaction_autocommit(view, seq, fields) < 0)
 		return NULL;
-	/* FIXME: check cache_offset in transaction
-	   FIXME: if rec doesn't point to header record, the file seq may
-	   be different and the offset wrong */
-	if (mail_index_lookup(view->view, seq, &rec) < 0)
+
+	if (view->cache->disabled)
+		return NULL;
+
+	/* FIXME: check cache_offset in transaction */
+	if (mail_index_lookup_full(view->view, seq, &map, &rec) < 0)
 		return NULL;
 
+	if (map->hdr->cache_file_seq != view->cache->hdr->file_seq) {
+		/* FIXME: we should check if newer file is available? */
+		return NULL;
+	}
+
 	return mail_cache_get_record(view->cache, rec->cache_offset, TRUE);
 }
 
diff --git a/src/lib-index/mail-cache-private.h b/src/lib-index/mail-cache-private.h
index 50e93bbf21..5cdc4e3e23 100644
--- a/src/lib-index/mail-cache-private.h
+++ b/src/lib-index/mail-cache-private.h
@@ -58,7 +58,6 @@ struct mail_cache {
 
 	void *mmap_base;
 	size_t mmap_length;
-	uint32_t used_file_size;
 
 	struct mail_cache_header *hdr;
 
@@ -74,6 +73,7 @@ struct mail_cache {
 
 	unsigned int mmap_refresh:1;
 	unsigned int silent:1;
+	unsigned int disabled:1;
 };
 
 struct mail_cache_view {
diff --git a/src/lib-index/mail-cache-transaction.c b/src/lib-index/mail-cache-transaction.c
index 99fd8a7068..badc732170 100644
--- a/src/lib-index/mail-cache-transaction.c
+++ b/src/lib-index/mail-cache-transaction.c
@@ -22,6 +22,7 @@ struct mail_cache_transaction_ctx {
 	uint32_t first_seq, last_seq, prev_seq;
 	enum mail_cache_field prev_fields;
 	buffer_t *cache_marks;
+	uint32_t used_file_size;
 };
 
 static const unsigned char *null4[] = { 0, 0, 0, 0 };
@@ -44,6 +45,7 @@ int mail_cache_transaction_begin(struct mail_cache_view *view, int nonblock,
 	ctx->view = view;
 	ctx->trans = t;
 	ctx->cache_data = buffer_create_dynamic(system_pool, 8192, (size_t)-1);
+	ctx->used_file_size = nbo_to_uint32(ctx->cache->hdr->used_file_size);
 
 	view->cache->trans_ctx = ctx;
 	*ctx_r = ctx;
@@ -141,7 +143,7 @@ static int commit_all_changes(struct mail_cache_transaction_ctx *ctx)
 
 	if (cont * 100 / cache->index->hdr->messages_count >=
 	    COMPRESS_CONTINUED_PERCENTAGE &&
-	    cache->used_file_size >= COMPRESS_MIN_SIZE) {
+	    ctx->used_file_size >= COMPRESS_MIN_SIZE) {
 		/* too many continued rows, compress */
 		//FIXME:cache->index->set_flags |= MAIL_INDEX_HDR_FLAG_COMPRESS_CACHE;
 	}
@@ -150,12 +152,14 @@ static int commit_all_changes(struct mail_cache_transaction_ctx *ctx)
 	return 0;
 }
 
-static int mail_cache_grow(struct mail_cache *cache, uint32_t size)
+static int
+mail_cache_grow(struct mail_cache_transaction_ctx *ctx, uint32_t size)
 {
+        struct mail_cache *cache = ctx->cache;
 	struct stat st;
 	uoff_t grow_size, new_fsize;
 
-	new_fsize = cache->used_file_size + size;
+	new_fsize = ctx->used_file_size + size;
 	grow_size = new_fsize / 100 * MAIL_CACHE_GROW_PERCENTAGE;
 	if (grow_size < 16384)
 		grow_size = 16384;
@@ -168,7 +172,7 @@ static int mail_cache_grow(struct mail_cache *cache, uint32_t size)
 		return -1;
 	}
 
-	if (cache->used_file_size + size <= (uoff_t)st.st_size) {
+	if (ctx->used_file_size + size <= (uoff_t)st.st_size) {
 		/* no need to grow, just update mmap */
 		if (mail_cache_mmap_update(cache, 0, 0) < 0)
 			return -1;
@@ -193,7 +197,7 @@ static uint32_t mail_cache_append_space(struct mail_cache_transaction_ctx *ctx,
 
 	i_assert((size & 3) == 0);
 
-	offset = ctx->cache->used_file_size;
+	offset = ctx->used_file_size;
 	if (offset >= 0x40000000) {
 		mail_index_set_error(ctx->cache->index,
 				     "Cache file too large: %s",
@@ -202,11 +206,11 @@ static uint32_t mail_cache_append_space(struct mail_cache_transaction_ctx *ctx,
 	}
 
 	if (offset + size > ctx->cache->mmap_length) {
-		if (mail_cache_grow(ctx->cache, size) < 0)
+		if (mail_cache_grow(ctx, size) < 0)
 			return 0;
 	}
 
-	ctx->cache->used_file_size += size;
+	ctx->used_file_size += size;
 	return offset;
 }
 
@@ -215,6 +219,7 @@ static int mail_cache_write(struct mail_cache_transaction_ctx *ctx)
 	struct mail_cache *cache = ctx->cache;
 	struct mail_cache_record *cache_rec, *next;
 	const struct mail_index_record *rec;
+	struct mail_index_map *map;
 	uint32_t write_offset, update_offset;
 	const void *buf;
 	size_t size, buf_size;
@@ -226,10 +231,16 @@ static int mail_cache_write(struct mail_cache_transaction_ctx *ctx)
 	ctx->cache_rec.size = uint32_to_nbo(size);
 
 	// FIXME: check cache_offset in transaction
-	ret = mail_index_lookup(ctx->view->view, ctx->prev_seq, &rec);
+	ret = mail_index_lookup_full(ctx->view->view, ctx->prev_seq,
+				     &map, &rec);
 	if (ret < 0)
 		return -1;
 
+	if (map->hdr->cache_file_seq != cache->hdr->file_seq) {
+		/* FIXME: we should check if newer file is available? */
+		ret = 0;
+	}
+
 	if (ret == 0) {
 		/* it's been expunged already, do nothing */
 	} else {
@@ -275,13 +286,17 @@ int mail_cache_transaction_commit(struct mail_cache_transaction_ctx *ctx)
 {
 	int ret = 0;
 
+	if (ctx->cache->disabled) {
+		mail_cache_transaction_flush(ctx);
+		return 0;
+	}
+
 	if (ctx->prev_seq != 0) {
 		if (mail_cache_write(ctx) < 0)
 			return -1;
 	}
 
-	ctx->cache->hdr->used_file_size =
-		uint32_to_nbo(ctx->cache->used_file_size);
+	ctx->cache->hdr->used_file_size = uint32_to_nbo(ctx->used_file_size);
 
 	if (commit_all_changes(ctx) < 0)
 		ret = -1;
@@ -303,7 +318,7 @@ void mail_cache_transaction_rollback(struct mail_cache_transaction_ctx *ctx)
 
 	/* no need to actually modify the file - we just didn't update
 	   used_file_size */
-	cache->used_file_size = nbo_to_uint32(cache->hdr->used_file_size);
+	ctx->used_file_size = nbo_to_uint32(cache->hdr->used_file_size);
 
 	/* make sure we don't cache the headers */
 	for (i = 0; i < ctx->next_unused_header_lowwater; i++) {
@@ -532,9 +547,9 @@ int mail_cache_delete(struct mail_cache_transaction_ctx *ctx, uint32_t seq)
 	} while (cache_rec != NULL);
 
 	/* see if we've reached the max. deleted space in file */
-	max_del_space = cache->used_file_size / 100 * COMPRESS_PERCENTAGE;
+	max_del_space = ctx->used_file_size / 100 * COMPRESS_PERCENTAGE;
 	if (deleted_space >= max_del_space &&
-	    cache->used_file_size >= COMPRESS_MIN_SIZE) {
+	    ctx->used_file_size >= COMPRESS_MIN_SIZE) {
 		//FIXME:cache->index->set_flags |= MAIL_INDEX_HDR_FLAG_COMPRESS_CACHE;
 	}
 
diff --git a/src/lib-index/mail-cache.c b/src/lib-index/mail-cache.c
index 58a631ad48..9c05007dd4 100644
--- a/src/lib-index/mail-cache.c
+++ b/src/lib-index/mail-cache.c
@@ -136,6 +136,7 @@ static int mail_cache_file_reopen(struct mail_cache *cache)
 static int mmap_verify_header(struct mail_cache *cache)
 {
 	struct mail_cache_header *hdr;
+	uint32_t used_file_size;
 
 	/* check that the header is still ok */
 	if (cache->mmap_length < sizeof(struct mail_cache_header)) {
@@ -156,28 +157,23 @@ static int mmap_verify_header(struct mail_cache *cache)
 		return 1;
 	}
 
-	cache->used_file_size = nbo_to_uint32(hdr->used_file_size);
-
 	/* only check the header if we're locked */
 	if (cache->locks == 0)
 		return 1;
 
-	if (cache->used_file_size < sizeof(struct mail_cache_header)) {
+	used_file_size = nbo_to_uint32(hdr->used_file_size);
+	if (used_file_size < sizeof(struct mail_cache_header)) {
 		mail_cache_set_corrupted(cache, "used_file_size too small");
 		return 0;
 	}
-	if ((cache->used_file_size % sizeof(uint32_t)) != 0) {
+	if ((used_file_size % sizeof(uint32_t)) != 0) {
 		mail_cache_set_corrupted(cache, "used_file_size not aligned");
 		return 0;
 	}
 
-	if (cache->used_file_size > cache->mmap_length) {
-		/* maybe a crash truncated the file - just fix it */
-		hdr->used_file_size = uint32_to_nbo(cache->mmap_length & ~3);
-		if (msync(cache->mmap_base, sizeof(*hdr), MS_SYNC) < 0) {
-			mail_cache_set_syscall_error(cache, "msync()");
-			return -1;
-		}
+	if (used_file_size > cache->mmap_length) {
+		mail_cache_set_corrupted(cache, "used_file_size too large");
+		return 0;
 	}
 	return 1;
 }
@@ -354,10 +350,6 @@ static int mail_cache_open_or_create_file(struct mail_cache *cache,
 		return -1;
 	}
 
-	if (cache->index->hdr->cache_file_seq != 0) {
-		// FIXME: clear cache_offsets in index file
-	}
-
 	mail_cache_file_close(cache);
 	cache->fd = dup(fd);
 
@@ -388,12 +380,15 @@ struct mail_cache *mail_cache_open_or_create(struct mail_index *index)
 	cache->fd = -1;
         cache->split_header_pool = pool_alloconly_create("Headers", 512);
 
-	/* we'll do anon-mmaping only if initially requested. if we fail
-	   because of out of disk space, we'll just let the main index code
-	   know it and fail. */
 	if (mail_cache_open_or_create_file(cache, &hdr) < 0) {
-		mail_cache_free(cache);
-		return NULL;
+		/* failed for some reason - doesn't really matter,
+		   just disable caching. */
+		mail_cache_file_close(cache);
+
+		i_free(cache->filepath);
+		cache->filepath = i_strdup_printf("(disabled cache for %s)",
+						  index->filepath);
+		cache->disabled = TRUE;
 	}
 
 	return cache;
@@ -423,15 +418,10 @@ int mail_cache_reset(struct mail_cache *cache)
 	struct mail_cache_header hdr;
 	int fd;
 
-	i_assert(cache->index->lock_type == F_WRLCK);
-
 	memset(&hdr, 0, sizeof(hdr));
 	hdr.indexid = cache->index->indexid;
 	hdr.file_seq = cache->index->hdr->cache_file_seq + 1;
 	hdr.used_file_size = uint32_to_nbo(sizeof(hdr));
-	cache->used_file_size = sizeof(hdr);
-
-	// FIXME: update cache_offsets in index
 
 	fd = file_dotlock_open(cache->filepath, NULL, NULL,
 			       MAIL_CACHE_LOCK_TIMEOUT,
@@ -491,18 +481,11 @@ int mail_cache_lock(struct mail_cache *cache, int nonblock)
 			(void)mail_cache_unlock(cache);
 			return -1;
 		}
-#if 0 // FIXME
+
 		if (cache->hdr->file_seq != cache->index->hdr->cache_file_seq) {
-			/* we have the cache file locked and sync_id still
-			   doesn't match. it means we crashed between updating
-			   cache file and updating sync_id in index header.
-			   just update the sync_ids so they match. */
-			i_warning("Updating broken sync_id in cache file %s",
-				  cache->filepath);
-			cache->hdr->file_seq =
-				cache->index->hdr->cache_file_seq;
+			mail_cache_unlock(cache);
+			return 0;
 		}
-#endif
 	}
 	return ret;
 }
@@ -525,6 +508,18 @@ int mail_cache_is_locked(struct mail_cache *cache)
 	return cache->locks > 0;
 }
 
+int mail_cache_need_reset(struct mail_cache *cache, uint32_t *new_file_seq_r)
+{
+	if (cache->hdr->file_seq != cache->index->hdr->cache_file_seq) {
+		if (mail_cache_lock(cache, TRUE) == 0) {
+			*new_file_seq_r = cache->index->hdr->cache_file_seq;
+			return TRUE;
+		}
+	}
+
+	return FALSE;
+}
+
 struct mail_cache_view *
 mail_cache_view_open(struct mail_cache *cache, struct mail_index_view *iview)
 {
diff --git a/src/lib-index/mail-cache.h b/src/lib-index/mail-cache.h
index aa4823db72..5317883b0d 100644
--- a/src/lib-index/mail-cache.h
+++ b/src/lib-index/mail-cache.h
@@ -81,14 +81,17 @@ int mail_cache_compress(struct mail_cache *cache);
 /* Reset the cache file, clearing all data. */
 int mail_cache_reset(struct mail_cache *cache);
 
-/* Explicitly lock the cache file. Returns 1 if ok, 0 if nonblock is TRUE and
-   we couldn't immediately get a lock, or -1 if error. */
+/* Explicitly lock the cache file. Returns -1 if error, 1 if ok,
+   0 if we couldn't lock (nonblock = TRUE or index file needs a cache reset) */
 int mail_cache_lock(struct mail_cache *cache, int nonblock);
 int mail_cache_unlock(struct mail_cache *cache);
 
 /* Returns TRUE if cache file is locked. */
 int mail_cache_is_locked(struct mail_cache *cache);
 
+/* Returns TRUE if index's cache_file_seq doesn't match the latest cache file */
+int mail_cache_need_reset(struct mail_cache *cache, uint32_t *new_file_seq_r);
+
 struct mail_cache_view *
 mail_cache_view_open(struct mail_cache *cache, struct mail_index_view *iview);
 void mail_cache_view_close(struct mail_cache_view *view);
diff --git a/src/lib-index/mail-index-private.h b/src/lib-index/mail-index-private.h
index 23d410ca61..ffd5a0b415 100644
--- a/src/lib-index/mail-index-private.h
+++ b/src/lib-index/mail-index-private.h
@@ -124,6 +124,12 @@ void mail_index_unmap(struct mail_index *index, struct mail_index_map *map);
 struct mail_index_map *
 mail_index_map_to_memory(struct mail_index *index, struct mail_index_map *map);
 
+int mail_index_lookup_full(struct mail_index_view *view, uint32_t seq,
+			   struct mail_index_map **map_r,
+			   const struct mail_index_record **rec_r);
+
+void mail_index_reset_cache(struct mail_index_transaction *t,
+			    uint32_t new_file_seq);
 void mail_index_update_cache(struct mail_index_transaction *t,
 			     uint32_t seq, uint32_t offset);
 
diff --git a/src/lib-index/mail-index-sync-update.c b/src/lib-index/mail-index-sync-update.c
index fc65434937..48fabe351a 100644
--- a/src/lib-index/mail-index-sync-update.c
+++ b/src/lib-index/mail-index-sync-update.c
@@ -178,6 +178,19 @@ static int sync_flag_update(const struct mail_transaction_flag_update *u,
 	return 1;
 }
 
+static int sync_cache_reset(const struct mail_transaction_cache_reset *u,
+			    void *context)
+{
+	struct mail_index_view *view = context;
+	uint32_t i;
+
+	view->map->hdr_copy.cache_file_seq = u->new_file_seq;
+
+	for (i = 0; i < view->messages_count; i++)
+		MAIL_INDEX_MAP_IDX(view->index, view->map, i)->cache_offset = 0;
+	return 1;
+}
+
 static int sync_cache_update(const struct mail_transaction_cache_update *u,
 			     void *context)
 {
@@ -374,5 +387,6 @@ int mail_index_sync_update_index(struct mail_index_sync_ctx *sync_ctx)
 
 struct mail_transaction_map_functions mail_index_map_sync_funcs = {
 	sync_expunge, sync_append, sync_flag_update,
-	sync_cache_update, sync_header_update, sync_extra_rec_update
+	sync_cache_reset, sync_cache_update, sync_header_update,
+	sync_extra_rec_update
 };
diff --git a/src/lib-index/mail-index-sync.c b/src/lib-index/mail-index-sync.c
index 4848a12db2..b21ba2a790 100644
--- a/src/lib-index/mail-index-sync.c
+++ b/src/lib-index/mail-index-sync.c
@@ -125,7 +125,7 @@ int mail_index_sync_begin(struct mail_index *index,
 			  uint32_t log_file_seq, uoff_t log_file_offset)
 {
 	struct mail_index_sync_ctx *ctx;
-	uint32_t seq;
+	uint32_t seq, new_file_seq;
 	uoff_t offset;
 	unsigned int lock_id;
 
@@ -178,6 +178,17 @@ int mail_index_sync_begin(struct mail_index *index,
 		return -1;
 	}
 
+	/* check here if cache file's sequence has changed unexpectedly */
+	if (mail_cache_need_reset(index->cache, &new_file_seq)) {
+		uint32_t seq;
+		uoff_t offset;
+		struct mail_index_transaction *t;
+
+		t = mail_index_transaction_begin(ctx->view, FALSE);
+		mail_index_reset_cache(t, new_file_seq);
+                mail_index_transaction_commit(t, &seq, &offset);
+	}
+
 	*ctx_r = ctx;
 	*view_r = ctx->view;
 	return 1;
diff --git a/src/lib-index/mail-index-transaction-private.h b/src/lib-index/mail-index-transaction-private.h
index f6be129e19..d0efb4e31c 100644
--- a/src/lib-index/mail-index-transaction-private.h
+++ b/src/lib-index/mail-index-transaction-private.h
@@ -15,6 +15,7 @@ struct mail_index_transaction {
 
 	unsigned char hdr_change[sizeof(struct mail_index_header)];
 	unsigned char hdr_mask[sizeof(struct mail_index_header)];
+	uint32_t new_cache_file_seq;
 
 	buffer_t *extra_rec_updates[MAIL_INDEX_MAX_EXTRA_RECORDS];
 
diff --git a/src/lib-index/mail-index-transaction.c b/src/lib-index/mail-index-transaction.c
index 0c627cf9fd..b4da4bd478 100644
--- a/src/lib-index/mail-index-transaction.c
+++ b/src/lib-index/mail-index-transaction.c
@@ -474,6 +474,12 @@ static void mail_index_update_seq_buffer(buffer_t **buffer, uint32_t seq,
 	memcpy(seq_p+1, record, record_size);
 }
 
+void mail_index_reset_cache(struct mail_index_transaction *t,
+			    uint32_t new_file_seq)
+{
+	t->new_cache_file_seq = new_file_seq;
+}
+
 void mail_index_update_cache(struct mail_index_transaction *t,
 			     uint32_t seq, uint32_t offset)
 {
diff --git a/src/lib-index/mail-index-view.c b/src/lib-index/mail-index-view.c
index 3f6fa93b5b..9d1fdd441d 100644
--- a/src/lib-index/mail-index-view.c
+++ b/src/lib-index/mail-index-view.c
@@ -160,9 +160,9 @@ int mail_index_get_header(struct mail_index_view *view,
 	return 0;
 }
 
-static int mail_index_lookup_int(struct mail_index_view *view, uint32_t seq,
-				 struct mail_index_map **map_r,
-				 const struct mail_index_record **rec_r)
+int mail_index_lookup_full(struct mail_index_view *view, uint32_t seq,
+			   struct mail_index_map **map_r,
+			   const struct mail_index_record **rec_r)
 {
 	struct mail_index_map *map;
 	const struct mail_index_record *rec, *n_rec;
@@ -218,7 +218,7 @@ int mail_index_lookup(struct mail_index_view *view, uint32_t seq,
 {
 	struct mail_index_map *map;
 
-	return mail_index_lookup_int(view, seq, &map, rec_r);
+	return mail_index_lookup_full(view, seq, &map, rec_r);
 }
 
 int mail_index_lookup_uid(struct mail_index_view *view, uint32_t seq,
@@ -242,7 +242,7 @@ int mail_index_lookup_extra(struct mail_index_view *view, uint32_t seq,
 	uint32_t offset;
 	int ret;
 
-	if ((ret = mail_index_lookup_int(view, seq, &map, &rec)) < 0)
+	if ((ret = mail_index_lookup_full(view, seq, &map, &rec)) < 0)
 		return -1;
 
 	if (rec == NULL) {
diff --git a/src/lib-index/mail-transaction-log.c b/src/lib-index/mail-transaction-log.c
index aafe37eda0..564c98daa3 100644
--- a/src/lib-index/mail-transaction-log.c
+++ b/src/lib-index/mail-transaction-log.c
@@ -982,6 +982,19 @@ static int log_append_buffer(struct mail_transaction_log_file *file,
 	return 0;
 }
 
+static const buffer_t *get_cache_reset_buf(struct mail_index_transaction *t)
+{
+	struct mail_transaction_cache_reset u;
+	buffer_t *buf;
+
+	memset(&u, 0, sizeof(u));
+	u.new_file_seq = t->new_cache_file_seq;
+
+	buf = buffer_create_static(pool_datastack_create(), sizeof(u));
+	buffer_append(buf, &u, sizeof(u));
+	return buf;
+}
+
 static const buffer_t *
 log_get_hdr_update_buffer(struct mail_index_transaction *t)
 {
@@ -1089,6 +1102,11 @@ int mail_transaction_log_append(struct mail_index_transaction *t,
 					MAIL_TRANSACTION_FLAG_UPDATE,
 					view->external);
 	}
+	if (t->new_cache_file_seq != 0) {
+		ret = log_append_buffer(file, get_cache_reset_buf(t), NULL,
+					MAIL_TRANSACTION_CACHE_RESET,
+					view->external);
+	}
 	if (t->cache_updates != NULL && ret == 0) {
 		ret = log_append_buffer(file, t->cache_updates, NULL,
 					MAIL_TRANSACTION_CACHE_UPDATE,
diff --git a/src/lib-index/mail-transaction-log.h b/src/lib-index/mail-transaction-log.h
index cb6745bde9..572f7a7ee5 100644
--- a/src/lib-index/mail-transaction-log.h
+++ b/src/lib-index/mail-transaction-log.h
@@ -17,9 +17,10 @@ enum mail_transaction_type {
 	MAIL_TRANSACTION_EXPUNGE		= 0x00000001,
 	MAIL_TRANSACTION_APPEND			= 0x00000002,
 	MAIL_TRANSACTION_FLAG_UPDATE		= 0x00000004,
-	MAIL_TRANSACTION_CACHE_UPDATE		= 0x00000008,
-	MAIL_TRANSACTION_HEADER_UPDATE		= 0x00000010,
-	MAIL_TRANSACTION_EXTRA_REC_UPDATE	= 0x00000020,
+	MAIL_TRANSACTION_CACHE_RESET		= 0x00000008,
+	MAIL_TRANSACTION_CACHE_UPDATE		= 0x00000010,
+	MAIL_TRANSACTION_HEADER_UPDATE		= 0x00000020,
+	MAIL_TRANSACTION_EXTRA_REC_UPDATE	= 0x00000040,
 
 	MAIL_TRANSACTION_TYPE_MASK		= 0x0000ffff,
 
@@ -50,6 +51,10 @@ struct mail_transaction_flag_update {
 	keywords_mask_t remove_keywords;
 };
 
+struct mail_transaction_cache_reset {
+	uint32_t new_file_seq;
+};
+
 struct mail_transaction_cache_update {
 	uint32_t uid;
 	uint32_t cache_offset;
diff --git a/src/lib-index/mail-transaction-util.c b/src/lib-index/mail-transaction-util.c
index 276507c51f..cb102b29c2 100644
--- a/src/lib-index/mail-transaction-util.c
+++ b/src/lib-index/mail-transaction-util.c
@@ -20,6 +20,8 @@ const struct mail_transaction_type_map mail_transaction_type_map[] = {
 	  sizeof(struct mail_transaction_expunge) },
 	{ MAIL_TRANSACTION_FLAG_UPDATE, MAIL_INDEX_SYNC_TYPE_FLAGS,
 	  sizeof(struct mail_transaction_flag_update) },
+	{ MAIL_TRANSACTION_CACHE_RESET, 0,
+	  sizeof(struct mail_transaction_cache_reset) },
 	{ MAIL_TRANSACTION_CACHE_UPDATE, 0,
 	  sizeof(struct mail_transaction_cache_update) },
 	{ MAIL_TRANSACTION_HEADER_UPDATE, 0, 1 }, /* variable size, use 1 */
@@ -107,6 +109,13 @@ int mail_transaction_map(struct mail_index *index,
 		}
 		break;
 	}
+	case MAIL_TRANSACTION_CACHE_RESET: {
+		const struct mail_transaction_cache_reset *u = data;
+
+		if (map->cache_reset != NULL)
+			ret = map->cache_reset(u, context);
+		break;
+	}
 	case MAIL_TRANSACTION_CACHE_UPDATE: {
 		const struct mail_transaction_cache_update *rec, *end;
 
diff --git a/src/lib-index/mail-transaction-util.h b/src/lib-index/mail-transaction-util.h
index 8bf6dd83be..45303fbd1d 100644
--- a/src/lib-index/mail-transaction-util.h
+++ b/src/lib-index/mail-transaction-util.h
@@ -13,6 +13,8 @@ struct mail_transaction_map_functions {
 	int (*append)(const struct mail_index_record *rec, void *context);
 	int (*flag_update)(const struct mail_transaction_flag_update *u,
 			   void *context);
+	int (*cache_reset)(const struct mail_transaction_cache_reset *u,
+			    void *context);
 	int (*cache_update)(const struct mail_transaction_cache_update *u,
 			    void *context);
 	int (*header_update)(const struct mail_transaction_header_update *u,