dedup

commit 13bf2f947a35134d17043151e3a07f7aa86155b1
parent bea0c2a2d0e5dd3b04fd7888bcaf6ab3eb87fa79
Author: sin <sin@2f30.org>
Date:   Sun,  3 Mar 2019 13:24:04 +0000

Store store compression status in the store header

Diffstat:
M
dedup.c
 | 
10
++++++++++
M
dedup.h
 | 
3
+++

2 files changed, 13 insertions(+), 0 deletions(-)
diff --git a/dedup.c b/dedup.c
@@ -511,15 +511,25 @@ static void
 init_blk_hdr(void)
 {
 	blk_hdr.flags = (VER_MAJ << VER_MAJ_SHIFT) | VER_MIN;
+	blk_hdr.flags |= compr_enabled << COMPR_ENABLED_SHIFT;
 	blk_hdr.size = BLK_HDR_SIZE;
 }
 
 static void
 load_blk_hdr(void)
 {
+	uint64_t v;
+
 	xlseek(sfd, 0, SEEK_SET);
 	read_blk_hdr(sfd, &blk_hdr);
 	match_ver(blk_hdr.flags);
+
+	v = blk_hdr.flags >> COMPR_ENABLED_SHIFT;
+	v &= COMPR_ENABLED_MASK;
+	if (v != compr_enabled)
+		errx(1, "store is %s but dedup was invoked %s",
+		     v ? "compressed" : "not compressed",
+		     compr_enabled ? "with compression" : "without compression");
 }
 
 static void
diff --git a/dedup.h b/dedup.h
@@ -23,6 +23,9 @@
 #define VER_MAJ_SHIFT	8
 #define VER_MAJ_MASK	0xff
 
+#define COMPR_ENABLED_SHIFT	16
+#define COMPR_ENABLED_MASK	0x1
+
 struct cache;
 struct chunker;