dedup

commit a5062b8799146166bf125a7f49630fa46d84639b
parent 918648012d5b18fa898b7338de99e16583a0f7f6
Author: sin <sin@2f30.org>
Date:   Thu, 25 Apr 2019 22:02:32 +0100

Implement block deletion

This code relies on fallocate(2) so it is not very portable.

Diffstat:
M
bcompress.c
 | 
10
++++++++++
M
block.c
 | 
12
++++++++++++
M
block.h
 | 
2
++
M
bstorage.c
 | 
38
++++++++++++++++++++++++++++++++++++++
M
config.mk
 | 
2
+-

5 files changed, 63 insertions(+), 1 deletion(-)
diff --git a/bcompress.c b/bcompress.c
@@ -25,6 +25,7 @@ static int bccreat(struct bctx *bctx, char *path, int mode, struct bparam *bpar)
 static int bcopen(struct bctx *bctx, char *path, int flags, int mode, struct bparam *bpar);
 static int bcput(struct bctx *bctx, void *buf, size_t n, unsigned char *md);
 static int bcget(struct bctx *bctx, unsigned char *md, void *buf, size_t *n);
+static int bcrm(struct bctx *bctx, unsigned char *md);
 static int bccheck(struct bctx *bctx, unsigned char *md);
 static int bcsync(struct bctx *bctx);
 static int bcclose(struct bctx *bctx);
@@ -34,6 +35,7 @@ static struct bops bops = {
 	.open = bcopen,
 	.put = bcput,
 	.get = bcget,
+	.rm = bcrm,
 	.check = bccheck,
 	.sync = bcsync,
 	.close = bcclose,
@@ -238,6 +240,14 @@ bcget(struct bctx *bctx, unsigned char *md, void *buf, size_t *n)
 }
 
 static int
+bcrm(struct bctx *bctx, unsigned char *md)
+{
+	struct bops *bops = bstorageops();
+
+	return bops->rm(bctx, md);
+}
+
+static int
 bccheck(struct bctx *bctx, unsigned char *md)
 {
 	struct bops *bops = bstorageops();
diff --git a/block.c b/block.c
@@ -78,6 +78,18 @@ bget(struct bctx *bctx, unsigned char *md, void *buf, size_t *n)
 }
 
 int
+brm(struct bctx *bctx, unsigned char *md)
+{
+	struct bops *bops;
+
+	if (bctx == NULL || md == NULL)
+		return -1;
+
+	bops = bcompressops();
+	return bops->rm(bctx, md);
+}
+
+int
 bcheck(struct bctx *bctx, unsigned char *md)
 {
 	struct bops *bops;
diff --git a/block.h b/block.h
@@ -17,6 +17,7 @@ struct bops {
 	int (*open)(struct bctx *bctx, char *path, int flags, int mode, struct bparam *bpar);
 	int (*put)(struct bctx *bctx, void *buf, size_t n, unsigned char *md);
 	int (*get)(struct bctx *bctx, unsigned char *md, void *buf, size_t *n);
+	int (*rm)(struct bctx *bctx, unsigned char *md);
 	int (*check)(struct bctx *bctx, unsigned char *md);
 	int (*sync)(struct bctx *bctx);
 	int (*close)(struct bctx *bctx);
@@ -27,6 +28,7 @@ extern int bcreat(char *path, int mode, struct bparam *bpar, struct bctx **bctx)
 extern int bopen(char *path, int flags, int mode, struct bparam *bpar, struct bctx **bctx);
 extern int bput(struct bctx *bctx, void *buf, size_t n, unsigned char *md);
 extern int bget(struct bctx *bctx, unsigned char *md, void *buf, size_t *n);
+extern int brm(struct bctx *bctx, unsigned char *md);
 extern int bcheck(struct bctx *bctx, unsigned char *md);
 extern int bsync(struct bctx *bctx);
 extern int bclose(struct bctx *bctx);
diff --git a/bstorage.c b/bstorage.c
@@ -51,6 +51,7 @@ static int bscreat(struct bctx *bctx, char *path, int mode, struct bparam *bpar)
 static int bsopen(struct bctx *bctx, char *path, int flags, int mode, struct bparam *bpar);
 static int bsput(struct bctx *bctx, void *buf, size_t n, unsigned char *md);
 static int bsget(struct bctx *bctx, unsigned char *md, void *buf, size_t *n);
+static int bsrm(struct bctx *bctx, unsigned char *md);
 static int bscheck(struct bctx *bctx, unsigned char *md);
 static int bssync(struct bctx *bctx);
 static int bsclose(struct bctx *bctx);
@@ -60,6 +61,7 @@ static struct bops bops = {
 	.open = bsopen,
 	.put = bsput,
 	.get = bsget,
+	.rm = bsrm,
 	.check = bscheck,
 	.sync = bssync,
 	.close = bsclose,
@@ -536,6 +538,42 @@ bsget(struct bctx *bctx, unsigned char *md, void *buf, size_t *n)
 	return 0;
 }
 
+static int
+bsrm(struct bctx *bctx, unsigned char *md)
+{
+	struct sctx *sctx;
+	struct bd key, *bd;
+	off_t bdoffs;
+
+	sctx = bctx->sctx;
+
+	/* Lookup block in the cache */
+	memcpy(key.md, md, MDSIZE);
+	bd = RB_FIND(bdcache, &sctx->bdcache, &key);
+	if (bd == NULL)
+		return -1;
+
+	bdoffs = bd->offset - BDSIZE;
+	if (lseek(sctx->fd, bdoffs, SEEK_SET) < 0)
+		return -1;
+
+	bd->refcnt--;
+	if (packbd(sctx->fd, bd) < 0) {
+		bd->refcnt++;
+		return -1;
+	}
+
+	if (bd->refcnt == 0) {
+		int mode;
+
+		mode = FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE;
+		fallocate(sctx->fd, mode, bd->offset, bd->size);
+		RB_REMOVE(bdcache, &sctx->bdcache, bd);
+		free(bd);
+	}
+	return 0;
+}
+
 /*
  * Lookup the block and rehash it.  Check that the
  * resulting hash matches the given hash.
diff --git a/config.mk b/config.mk
@@ -2,5 +2,5 @@ VERSION = 1.0
 PREFIX = /usr/local
 MANPREFIX = $(PREFIX)/man
 
-CPPFLAGS = -I/usr/local/include -D_FILE_OFFSET_BITS=64
+CPPFLAGS = -I/usr/local/include -D_FILE_OFFSET_BITS=64 -D_GNU_SOURCE
 LDFLAGS = -L/usr/local/lib