dedup

commit 12641354d5c6d5d5a06b889df69ec71cbbeca176
parent cc98da662594f5538942073561082e92be19d9fb
Author: sin <sin@2f30.org>
Date:   Mon,  4 Mar 2019 16:12:01 +0000

Always check and rebuild the cache

It might be dangerous to proceed with a corrupt cache.

Diffstat:
M
dedup.c
 | 
97
+++++++++++++++++++++++++++++++++++++------------------------------------------

1 file changed, 46 insertions(+), 51 deletions(-)
diff --git a/dedup.c b/dedup.c
@@ -403,7 +403,7 @@ check_snap(struct snapshot *snap, void *arg)
  * that case.
  */
 static int
-check_cache(struct snapshot *snap, void *arg)
+check_cache_entry(struct snapshot *snap, void *arg)
 {
 	int *ret = arg;
 	uint64_t i;
@@ -429,18 +429,7 @@ check_cache(struct snapshot *snap, void *arg)
 }
 
 static int
-list(struct snapshot *snap, void *arg)
-{
-	print_md(stdout, snap->md, sizeof(snap->md));
-	if (snap->msg[0] != '\0')
-		printf("\t%s\n", snap->msg);
-	else
-		putchar('\n');
-	return WALK_CONTINUE;
-}
-
-static int
-rebuild_cache(struct snapshot *snap, void *arg)
+reload_cache(struct snapshot *snap, void *arg)
 {
 	uint8_t md[MDSIZE];
 	uint8_t *buf;
@@ -469,6 +458,17 @@ rebuild_cache(struct snapshot *snap, void *arg)
 	return WALK_CONTINUE;
 }
 
+static int
+list(struct snapshot *snap, void *arg)
+{
+	print_md(stdout, snap->md, sizeof(snap->md));
+	if (snap->msg[0] != '\0')
+		printf("\t%s\n", snap->msg);
+	else
+		putchar('\n');
+	return WALK_CONTINUE;
+}
+
 /* Walk through all snapshots and call fn() on each one */
 static void
 walk_snap(int (*fn)(struct snapshot *, void *), void *arg)
@@ -514,11 +514,30 @@ cache_nr_entries(void)
 	return sb.st_size / CACHE_ENTRY_SIZE;
 }
 
-static int
-flush_cache(struct cache_entry *cache_entry)
+static void
+check_cache(void)
 {
-	write_cache_entry(cfd, cache_entry);
-	return 0;
+	int ret;
+
+	if (cache_nr_entries() != snap_hdr.st.nr_blks) {
+		ret = -1;
+	} else {
+		xlseek(ifd, SNAP_HDR_SIZE, SEEK_SET);
+		ret = 0;
+		walk_snap(check_cache_entry, &ret);
+	}
+
+	if (ret != 0) {
+		free_cache(cache);
+		cache = alloc_cache();
+
+		if (ftruncate(cfd, 0) < 0)
+			err(1, "ftruncate");
+
+		xlseek(ifd, SNAP_HDR_SIZE, SEEK_SET);
+		xlseek(cfd, 0, SEEK_SET);
+		walk_snap(reload_cache, NULL);
+	}
 }
 
 static void
@@ -527,19 +546,10 @@ load_cache(void)
 	uint64_t nr_entries;
 	uint64_t i;
 
-	xlseek(cfd, 0, SEEK_SET);
+	check_cache();
 
+	xlseek(cfd, 0, SEEK_SET);
 	nr_entries = cache_nr_entries();
-	if (nr_entries == 0) {
-		xlseek(ifd, SNAP_HDR_SIZE, SEEK_SET);
-		if (verbose > 0)
-			fprintf(stderr, "Rebuilding cache...");
-		walk_snap(rebuild_cache, NULL);
-		if (verbose > 0)
-			fprintf(stderr, "done\n");
-		return;
-	}
-
 	for (i = 0; i < nr_entries; i++) {
 		struct cache_entry cache_entry;
 
@@ -548,6 +558,13 @@ load_cache(void)
 	}
 }
 
+static int
+flush_cache(struct cache_entry *cache_entry)
+{
+	write_cache_entry(cfd, cache_entry);
+	return 0;
+}
+
 static void
 save_cache(void)
 {
@@ -757,29 +774,7 @@ main(int argc, char *argv[])
 		if (ret != 0)
 			errx(1, "%s or %s is corrupted", SNAPSF, STOREF);
 
-		if (cache_nr_entries() != snap_hdr.st.nr_blks) {
-			ret = -1;
-		} else {
-			xlseek(ifd, SNAP_HDR_SIZE, SEEK_SET);
-			ret = 0;
-			walk_snap(check_cache, &ret);
-		}
-
-		if (ret != 0) {
-			free_cache(cache);
-			cache = alloc_cache();
-
-			if (ftruncate(cfd, 0) < 0)
-				err(1, "ftruncate");
-
-			if (verbose > 0)
-				fprintf(stderr, "Cache is corrupted, rebuilding...");
-			xlseek(ifd, SNAP_HDR_SIZE, SEEK_SET);
-			xlseek(cfd, 0, SEEK_SET);
-			walk_snap(rebuild_cache, NULL);
-			if (verbose > 0)
-				fprintf(stderr, "done\n");
-		}
+		check_cache();
 
 		term();
 		return 0;