From: Martin Mares <mj@ucw.cz>
Date: Fri, 5 Jul 2002 03:23:13 +0000 (+0000)
Subject: When an inconsistency is encountered while shaking down the bucket
X-Git-Tag: holmes-import~1389
X-Git-Url: http://mj.ucw.cz/gitweb/?a=commitdiff_plain;h=3e0a9c92e009b76b1a02aa344bea77c5d2e1c5db;p=libucw.git

When an inconsistency is encountered while shaking down the bucket
file, recover all data prior to the inconsistency by marking the
space between read and write pointer as deleted buckets (need to
use more of them if the space is too large).
---

diff --git a/lib/bucket.c b/lib/bucket.c
index e35f99f8..ad476004 100644
--- a/lib/bucket.c
+++ b/lib/bucket.c
@@ -321,7 +321,7 @@ obuck_delete(oid_t oid)
 void
 obuck_shakedown(int (*kibitz)(struct obuck_header *old, oid_t new, byte *buck))
 {
-  byte *rbuf, *wbuf;
+  byte *rbuf, *wbuf, *msg;
   sh_off_t rstart, wstart, w_bucket_start;
   int roff, woff, rsize, l;
   struct obuck_header *rhdr, *whdr;
@@ -343,12 +343,18 @@ obuck_shakedown(int (*kibitz)(struct obuck_header *old, oid_t new, byte *buck))
       rhdr = (struct obuck_header *)(rbuf + roff);
       if (rhdr->magic != OBUCK_MAGIC ||
 	  rhdr->oid != OBUCK_OID_DELETED && rhdr->oid != (bucket_start >> OBUCK_SHIFT))
-	obuck_broken("header mismatch during shakedown");
+	{
+	  msg = "header mismatch";
+	  goto broken;
+	}
       l = (sizeof(struct obuck_header) + rhdr->length + 4 + OBUCK_ALIGN - 1) & ~(OBUCK_ALIGN-1);
       if (rsize - roff < l)
 	goto reread;
       if (GET_U32(rbuf + roff + l - 4) != OBUCK_TRAILER)
-	obuck_broken("missing trailer during shakedown");
+	{
+	  msg = "missing trailer";
+	  goto broken;
+	}
       if (rhdr->oid != OBUCK_OID_DELETED)
 	{
 	  if (kibitz(rhdr, w_bucket_start >> OBUCK_SHIFT, (byte *)(rhdr+1)))
@@ -394,7 +400,8 @@ obuck_shakedown(int (*kibitz)(struct obuck_header *old, oid_t new, byte *buck))
 	{
 	  if (!rsize)
 	    break;
-	  obuck_broken("unexpected EOF during shakedown");
+	  msg = "unexpected EOF";
+	  goto broken;
 	}
       rsize += l;
     }
@@ -409,6 +416,30 @@ obuck_shakedown(int (*kibitz)(struct obuck_header *old, oid_t new, byte *buck))
   obuck_unlock();
   xfree(rbuf);
   xfree(wbuf);
+  return;
+
+ broken:
+  log(L_ERROR, "Error during object pool shakedown: %s (pos=%Ld), gathering debris", msg, (long long) bucket_start);
+  if (woff)
+    {
+      sh_pwrite(obuck_fd, wbuf, woff, wstart);
+      wstart += woff;
+    }
+  while (wstart + OBUCK_ALIGN <= bucket_start)
+    {
+      u32 check = OBUCK_TRAILER;
+      obuck_hdr.magic = OBUCK_MAGIC;
+      obuck_hdr.oid = OBUCK_OID_DELETED;
+      if (bucket_start - wstart < 0x40000000)
+	obuck_hdr.length = bucket_start - wstart - sizeof(obuck_hdr) - 4;
+      else
+	obuck_hdr.length = 0x40000000 - sizeof(obuck_hdr) - 4;
+      obuck_hdr.orig_length = obuck_hdr.length;
+      sh_pwrite(obuck_fd, &obuck_hdr, sizeof(obuck_hdr), wstart);
+      wstart += sizeof(obuck_hdr) + obuck_hdr.length + 4;
+      sh_pwrite(obuck_fd, &check, 4, wstart-4);
+    }
+  die("Fatal error during object pool shakedown");
 }
 
 /*** Testing ***/