From 7a4ee46d253e291044bba2d0c54b818b67ac013c Mon Sep 17 00:00:00 2001
From: rsc <devnull@localhost>
Date: Sun, 23 Nov 2003 17:54:58 +0000
Subject: Initial stab at Venti.

---
 src/cmd/venti/syncarena.c | 164 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 164 insertions(+)
 create mode 100644 src/cmd/venti/syncarena.c

(limited to 'src/cmd/venti/syncarena.c')

diff --git a/src/cmd/venti/syncarena.c b/src/cmd/venti/syncarena.c
new file mode 100644
index 00000000..78a6bd0f
--- /dev/null
+++ b/src/cmd/venti/syncarena.c
@@ -0,0 +1,164 @@
+#include "stdinc.h"
+#include "dat.h"
+#include "fns.h"
+
+static int	writeclumphead(Arena *arena, u64int aa, Clump *cl);
+static int	writeclumpmagic(Arena *arena, u64int aa, u32int magic);
+
+int
+clumpinfocmp(ClumpInfo *c, ClumpInfo *d)
+{
+	return c->type != d->type
+		|| c->size != d->size
+		|| c->uncsize != d->uncsize
+		|| scorecmp(c->score, d->score)!=0;
+}
+
+/*
+ * synchronize the clump info directory with
+ * with the clumps actually stored in the arena.
+ * the directory should be at least as up to date
+ * as the arena's trailer.
+ *
+ * checks/updates at most n clumps.
+ *
+ * returns 0 if ok, flags if error occurred
+ */
+int
+syncarena(Arena *arena, u32int n, int zok, int fix)
+{
+	ZBlock *lump;
+	Clump cl;
+	ClumpInfo ci;
+	static ClumpInfo zci = { .type = -1 };
+	u8int score[VtScoreSize];
+	u64int uncsize, used, aa;
+	u32int clump, clumps, cclumps, magic;
+	int err, flush, broken;
+
+	used = arena->used;
+	clumps = arena->clumps;
+	cclumps = arena->cclumps;
+	uncsize = arena->uncsize;
+
+	flush = 0;
+	err = 0;
+	for(; n; n--){
+		aa = arena->used;
+		clump = arena->clumps;
+		magic = clumpmagic(arena, aa);
+		if(magic == ClumpFreeMagic)
+			break;
+		if(magic != ClumpMagic){
+			fprint(2, "illegal clump magic number=%#8.8ux at clump=%d\n", magic, clump);
+			err |= SyncDataErr;
+//ZZZ write a zero here?
+			if(0 && fix && writeclumpmagic(arena, aa, ClumpFreeMagic) < 0){
+				fprint(2, "can't write corrected clump free magic: %r");
+				err |= SyncFixErr;
+			}
+			break;
+		}
+		arena->clumps++;
+
+		broken = 0;
+		lump = loadclump(arena, aa, 0, &cl, score, 0);
+		if(lump == nil){
+			fprint(2, "clump=%d failed to read correctly: %r\n", clump);
+			err |= SyncDataErr;
+		}else if(cl.info.type != VtTypeCorrupt){
+			scoremem(score, lump->data, cl.info.uncsize);
+			if(scorecmp(cl.info.score, score) != 0){
+				fprint(2, "clump=%d has mismatched score\n", clump);
+				err |= SyncDataErr;
+				broken = 1;
+			}else if(vttypevalid(cl.info.type) < 0){
+				fprint(2, "clump=%d has invalid type %d", clump, cl.info.type);
+				err |= SyncDataErr;
+				broken = 1;
+			}
+			if(broken && fix){
+				cl.info.type = VtTypeCorrupt;
+				if(writeclumphead(arena, aa, &cl) < 0){
+					fprint(2, "can't write corrected clump header: %r");
+					err |= SyncFixErr;
+				}
+			}
+		}
+		freezblock(lump);
+		arena->used += ClumpSize + cl.info.size;
+
+		if(!broken && readclumpinfo(arena, clump, &ci)<0){
+			fprint(2, "arena directory read failed\n");
+			broken = 1;
+		}else if(!broken && clumpinfocmp(&ci, &cl.info)!=0){
+			if(clumpinfocmp(&ci, &zci) == 0){
+				err |= SyncCIZero;
+				if(!zok)
+					fprint(2, "unwritten clump info for clump=%d\n", clump);
+			}else{
+				err |= SyncCIErr;
+				fprint(2, "bad clump info for clump=%d\n", clump);
+				fprint(2, "\texpected score=%V type=%d size=%d uncsize=%d\n",
+					cl.info.score, cl.info.type, cl.info.size, cl.info.uncsize);
+				fprint(2, "\tfound score=%V type=%d size=%d uncsize=%d\n",
+					ci.score, ci.type, ci.size, ci.uncsize);
+			}
+			broken = 1;
+		}
+		if(broken && fix){
+			flush = 1;
+			ci = cl.info;
+			if(writeclumpinfo(arena, clump, &ci) < 0){
+				fprint(2, "can't write correct clump directory: %r\n");
+				err |= SyncFixErr;
+			}
+		}
+
+		arena->uncsize += cl.info.uncsize;
+		if(cl.info.size < cl.info.uncsize)
+			arena->cclumps++;
+	}
+
+	if(flush){
+		arena->wtime = now();
+		if(arena->ctime == 0 && arena->clumps)
+			arena->ctime = arena->wtime;
+		if(flushciblocks(arena) < 0){
+			fprint(2, "can't flush arena directory cache: %r");
+			err |= SyncFixErr;
+		}
+	}
+
+	if(used != arena->used
+	|| clumps != arena->clumps
+	|| cclumps != arena->cclumps
+	|| uncsize != arena->uncsize)
+		err |= SyncHeader;
+
+	return err;
+}
+
+static int
+writeclumphead(Arena *arena, u64int aa, Clump *cl)
+{
+	ZBlock *zb;
+	int bad;
+
+	zb = alloczblock(ClumpSize, 0);
+	if(zb == nil)
+		return -1;
+	bad = packclump(cl, zb->data)<0
+		|| writearena(arena, aa, zb->data, ClumpSize) != ClumpSize;
+	freezblock(zb);
+	return bad ? -1 : 0;
+}
+
+static int
+writeclumpmagic(Arena *arena, u64int aa, u32int magic)
+{
+	u8int buf[U32Size];
+
+	packmagic(magic, buf);
+	return writearena(arena, aa, buf, U32Size) == U32Size;
+}
-- 
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