dedup

commit c14172d9472f2d53300a19b3fa27ddcbaba185d6
parent 7c3a4a21592d3c11e418e00964caadaec81613a5
Author: sin <sin@2f30.org>
Date:   Sun, 12 May 2019 19:36:07 +0100

Separate pack/unpack from write/read

Diffstat:
M
bstorage.c
 | 
36
++++++++++++++++++------------------

1 file changed, 18 insertions(+), 18 deletions(-)
diff --git a/bstorage.c b/bstorage.c
@@ -122,18 +122,12 @@ bhash(void *buf, size_t n, unsigned char *md)
 	return crypto_generichash(md, MDSIZE, buf, n, NULL, 0);
 }
 
-/* Read block header */
+/* Unpack block header */
 static int
-unpackbhdr(int fd, struct bhdr *bhdr)
+unpackbhdr(unsigned char *buf, struct bhdr *bhdr)
 {
-	unsigned char buf[BHDRSIZE];
 	int n;
 
-	if (xread(fd, buf, BHDRSIZE) != BHDRSIZE) {
-		seterr("failed to read block header: %s", strerror(errno));
-		return -1;
-	}
-
 	n = unpack(buf, "'16qq",
 	           bhdr->magic,
 	           &bhdr->flags,
@@ -145,9 +139,8 @@ unpackbhdr(int fd, struct bhdr *bhdr)
 
 /* Write block header */
 static int
-packbhdr(int fd, struct bhdr *bhdr)
+packbhdr(unsigned char *buf, struct bhdr *bhdr)
 {
-	unsigned char buf[BHDRSIZE];
 	int n;
 
 	n = pack(buf, "'16qq",
@@ -156,14 +149,10 @@ packbhdr(int fd, struct bhdr *bhdr)
 	         bhdr->nbd);
 
 	assert(n == BHDRSIZE);
-	if (xwrite(fd, buf, n) != n) {
-		seterr("failed to write block header: %s", strerror(errno));
-		return -1;
-	}
 	return n;
 }
 
-/* Read block descriptor */
+/* Unpack block descriptor */
 static int
 unpackbd(int fd, struct bd *bd)
 {
@@ -298,6 +287,7 @@ initbdcache(struct sctx *sctx)
 static int
 bscreat(struct bctx *bctx, char *path, int mode)
 {
+	unsigned char buf[BHDRSIZE];
 	struct sctx *sctx;
 	struct bhdr *bhdr;
 	int fd;
@@ -330,9 +320,11 @@ bscreat(struct bctx *bctx, char *path, int mode)
 	bhdr->flags = (VMAJ << VMAJSHIFT) | VMIN;
 	bhdr->nbd = 0;
 
-	if (packbhdr(fd, bhdr) < 0) {
+	packbhdr(buf, bhdr);
+	if (xwrite(fd, buf, BHDRSIZE) != BHDRSIZE) {
 		free(sctx);
 		close(fd);
+		seterr("failed to write block header: %s", strerror(errno));
 		return -1;
 	}
 	return 0;
@@ -342,6 +334,7 @@ bscreat(struct bctx *bctx, char *path, int mode)
 static int
 bsopen(struct bctx *bctx, char *path, int flags, int mode)
 {
+	unsigned char buf[BHDRSIZE];
 	struct sctx *sctx;
 	struct bhdr *bhdr;
 	int fd, algo;
@@ -381,11 +374,13 @@ bsopen(struct bctx *bctx, char *path, int flags, int mode)
 	SLIST_INIT(&sctx->gchead);
 	bhdr = &sctx->bhdr;
 
-	if (unpackbhdr(fd, bhdr) < 0) {
+	if (xread(fd, buf, BHDRSIZE) != BHDRSIZE) {
 		free(sctx);
 		close(fd);
+		seterr("failed to read block header: %s", strerror(errno));
 		return -1;
 	}
+	unpackbhdr(buf, bhdr);
 
 	if (memcmp(bhdr->magic, BHDRMAGIC, NBHDRMAGIC) != 0) {
 		free(sctx);
@@ -662,6 +657,7 @@ bscheck(struct bctx *bctx, unsigned char *md)
 static int
 bssync(struct bctx *bctx)
 {
+	unsigned char buf[BHDRSIZE];
 	struct sctx *sctx;
 	struct bhdr *bhdr;
 
@@ -673,9 +669,13 @@ bssync(struct bctx *bctx)
 		seterr("lseek: %s", strerror(errno));
 		return -1;
 	}
+
 	bhdr = &sctx->bhdr;
-	if (packbhdr(sctx->fd, bhdr) < 0)
+	packbhdr(buf, bhdr);
+	if (xwrite(sctx->fd, buf, BHDRSIZE) != BHDRSIZE) {
+		seterr("failed to write block header: %s", strerror(errno));
 		return -1;
+	}
 	fsync(sctx->fd);
 	return 0;
 }