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merge

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This commit is contained in:
Russ Cox
2008-04-15 19:17:51 -07:00
parent 715d6f8e14 715d6f8e14
commit 9f8a101a7c
5 changed files with 65 additions and 47 deletions
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26
src/cmd/venti/srv/conv.c
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@@ -177,6 +177,27 @@ unpackarena(Arena *arena, u8int *buf)
p += U64Size;
arena->memstats.sealed = U8GET(p);
p += U8Size;
/*
* 2008/4/2
* Packarena (below) used to have a bug in which it would
* not zero out any existing extension fields when writing
* the arena metadata. This would manifest itself as arenas
* with arena->diskstats.sealed == 1 but arena->memstats.sealed == 0
* after a server restart. Because arena->memstats.sealed wouldn't
* be set, the server might try to fit another block into the arena
* (and succeed), violating the append-only structure of the log
* and invalidating any already-computed seal on the arena.
*
* It might end up that other fields in arena->memstats end up
* behind arena->diskstats too, but that would be considerably
* more rare, and the bug is fixed now. The case we need to
* handle is just the sealed mismatch.
*
* If we encounter such a bogus arena, fix the sealed field.
*/
if(arena->diskstats.sealed)
arena->memstats.sealed = 1;
}else
arena->memstats = arena->diskstats;
if(buf + sz != p)
@@ -262,6 +283,11 @@ _packarena(Arena *arena, u8int *buf, int forceext)
p += U64Size;
U8PUT(p, arena->memstats.sealed);
p += U8Size;
}else{
/* Clear any extension fields already on disk. */
memset(p, 0, ArenaSize5a - ArenaSize5);
p += ArenaSize5a - ArenaSize5;
sz += ArenaSize5a - ArenaSize5;
}
if(buf + sz != p)