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Wapbl_register_deallocation(): the taken reader lock is not sufficient to 

protect wl_dealloc* members.  Take the mutex here and change the lock
requirements of these fields to "writer lock or mutex".

This error lead to file system corruption and "freeing free block" panics.
This commit is contained in:
hannken 2010-11-09 16:30:26 +00:00
parent 05738eefce
commit 897bf1dab0
1 changed files with 8 additions and 5 deletions
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13
sys/kern/vfs_wapbl.c
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@ -1,4 +1,4 @@
/* $NetBSD: vfs_wapbl.c,v 1.37 2010/09/10 10:14:55 drochner Exp $ */
/* $NetBSD: vfs_wapbl.c,v 1.38 2010/11/09 16:30:26 hannken Exp $ */
/*-
* Copyright (c) 2003, 2008, 2009 The NetBSD Foundation, Inc.
@ -36,7 +36,7 @@
#define WAPBL_INTERNAL
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: vfs_wapbl.c,v 1.37 2010/09/10 10:14:55 drochner Exp $");
__KERNEL_RCSID(0, "$NetBSD: vfs_wapbl.c,v 1.38 2010/11/09 16:30:26 hannken Exp $");
#include <sys/param.h>
#include <sys/bitops.h>
@ -104,6 +104,7 @@ MALLOC_JUSTDEFINE(M_WAPBL, "wapbl", "write-ahead physical block logging");
* r = read-only after init
* l = rwlock held
* m = mutex held
* lm = rwlock held writing or mutex held
* u = unlocked access ok
* b = bufcache_lock held
*/
@ -173,9 +174,9 @@ struct wapbl {
size_t wl_unsynced_bufbytes; /* Byte count of unsynced buffers */
#endif
daddr_t *wl_deallocblks;/* l: address of block */
int *wl_dealloclens; /* l: size of block */
int wl_dealloccnt; /* l: total count */
daddr_t *wl_deallocblks;/* lm: address of block */
int *wl_dealloclens; /* lm: size of block */
int wl_dealloccnt; /* lm: total count */
int wl_dealloclim; /* l: max count */
/* hashtable of inode numbers for allocated but unlinked inodes */
@ -1672,6 +1673,7 @@ wapbl_register_deallocation(struct wapbl *wl, daddr_t blk, int len)
wapbl_jlock_assert(wl);
mutex_enter(&wl->wl_mtx);
/* XXX should eventually instead tie this into resource estimation */
/*
* XXX this panic needs locking/mutex analysis and the
@ -1686,6 +1688,7 @@ wapbl_register_deallocation(struct wapbl *wl, daddr_t blk, int len)
wl->wl_dealloccnt++;
WAPBL_PRINTF(WAPBL_PRINT_ALLOC,
("wapbl_register_deallocation: blk=%"PRId64" len=%d\n", blk, len));
mutex_exit(&wl->wl_mtx);
}
/****************************************************************/