Module Name: src
Committed By: hannken
Date: Tue Nov 9 16:30:26 UTC 2010
Modified Files:
src/sys/kern: vfs_wapbl.c
Log Message:
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.
To generate a diff of this commit:
cvs rdiff -u -r1.37 -r1.38 src/sys/kern/vfs_wapbl.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/kern/vfs_wapbl.c
diff -u src/sys/kern/vfs_wapbl.c:1.37 src/sys/kern/vfs_wapbl.c:1.38
--- src/sys/kern/vfs_wapbl.c:1.37 Fri Sep 10 10:14:55 2010
+++ src/sys/kern/vfs_wapbl.c Tue Nov 9 16:30:26 2010
@@ -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 @@
* 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 @@
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_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 @@
wl->wl_dealloccnt++;
WAPBL_PRINTF(WAPBL_PRINT_ALLOC,
("wapbl_register_deallocation: blk=%"PRId64" len=%d\n", blk, len));
+ mutex_exit(&wl->wl_mtx);
}
/****************************************************************/
