dedup

commit 53b588c7899ecf4f4c969259e2c80f18192893ba
parent ff783e2a9af6d97d55697d654d759ca48d6a28a1
Author: sin <sin@2f30.org>
Date:   Sat, 27 Apr 2019 18:31:05 +0100

Add some comments

Diffstat:
M
bstorage.c
 | 
15
++++++++++-----

1 file changed, 10 insertions(+), 5 deletions(-)
diff --git a/bstorage.c b/bstorage.c
@@ -84,8 +84,8 @@ struct bhdr {
 /* Block descriptor */
 struct bd {
 	uint64_t type;
-	uint64_t offset;
-	uint64_t size;
+	uint64_t offset;	/* offset of block */
+	uint64_t size;		/* size of block */
 	uint64_t refcnt;
 	unsigned char md[MDSIZE];
 	RB_ENTRY(bd) rbe;
@@ -359,7 +359,6 @@ bscreat(struct bctx *bctx, char *path, int mode, struct bparam *bpar)
 		close(fd);
 		return -1;
 	}
-
 	bhdr->nbd = 0;
 	sctx->fd = fd;
 
@@ -484,6 +483,7 @@ bsput(struct bctx *bctx, void *buf, size_t n, unsigned char *md)
 		if (lseek(sctx->fd, bdoffs, SEEK_SET) < 0)
 			return -1;
 
+		/* Block already present, increment the reference count */
 		bd->refcnt++;
 		if (packbd(sctx->fd, bd) < 0) {
 			bd->refcnt--;
@@ -583,8 +583,7 @@ bsrm(struct bctx *bctx, unsigned char *md)
 	if (punchhole(sctx->fd, bd->offset, bd->size) < 0) {
 		/*
 		 * Filesystem does not support hole punching.
-		 * Try to recover the block descriptor so we don't
-		 * lose track of the block.
+		 * Restore reference count.
 		 */
 		lseek(sctx->fd, bdoffs, SEEK_SET);
 		bd->refcnt++;
@@ -592,6 +591,11 @@ bsrm(struct bctx *bctx, unsigned char *md)
 		return -1;
 	}
 
+	/*
+	 * Remove block from block descriptor cache as this is no
+	 * longer a valid block.  Insert it into the garbage collector
+	 * list instead.
+	 */
 	RB_REMOVE(bdcache, &sctx->bdcache, bd);
 	SLIST_INSERT_HEAD(&sctx->gchead, bd, sle);
 	return 0;
@@ -685,6 +689,7 @@ bsclose(struct bctx *bctx)
 		return -1;
 
 	sctx = bctx->sctx;
+
 	/* Free block descriptor cache */
 	RB_FOREACH_SAFE(bd, bdcache, &sctx->bdcache, tmp) {
 		RB_REMOVE(bdcache, &sctx->bdcache, bd);