Module Name: src
Committed By: hannken
Date: Mon Apr 9 11:10:07 UTC 2012
Modified Files:
src/sys/fs/msdosfs: msdosfs_fat.c
Log Message:
pcbmap(): We cannot use bread() here as for the pagedaemon getblk()
may fail leading to a panic in bread().
Replace bread() with getblk() / VOP_STRATEGY() and return
an error if getblk() fails.
Fixes PR#46282: 6.0_BETA crash: msdosfs_bmap -> pcbmap -> bread -> bio_doread
This is an interim solution for easy pullup. The final solution
is be to change bread() to not return a buffer on error. As
we have to change all callers of bread() this will not qualify
for a pullup.
To generate a diff of this commit:
cvs rdiff -u -r1.19 -r1.20 src/sys/fs/msdosfs/msdosfs_fat.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/fs/msdosfs/msdosfs_fat.c
diff -u src/sys/fs/msdosfs/msdosfs_fat.c:1.19 src/sys/fs/msdosfs/msdosfs_fat.c:1.20
--- src/sys/fs/msdosfs/msdosfs_fat.c:1.19 Tue Jan 26 20:25:52 2010
+++ src/sys/fs/msdosfs/msdosfs_fat.c Mon Apr 9 11:10:06 2012
@@ -1,4 +1,4 @@
-/* $NetBSD: msdosfs_fat.c,v 1.19 2010/01/26 20:25:52 joerg Exp $ */
+/* $NetBSD: msdosfs_fat.c,v 1.20 2012/04/09 11:10:06 hannken Exp $ */
/*-
* Copyright (C) 1994, 1995, 1997 Wolfgang Solfrank.
@@ -48,7 +48,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: msdosfs_fat.c,v 1.19 2010/01/26 20:25:52 joerg Exp $");
+__KERNEL_RCSID(0, "$NetBSD: msdosfs_fat.c,v 1.20 2012/04/09 11:10:06 hannken Exp $");
/*
* kernel include files.
@@ -254,11 +254,26 @@ pcbmap(struct denode *dep, u_long findcn
if (bn != bp_bn) {
if (bp)
brelse(bp, 0);
- error = bread(pmp->pm_devvp, de_bn2kb(pmp, bn), bsize,
- NOCRED, 0, &bp);
- if (error) {
- brelse(bp, 0);
- return (error);
+ bp = getblk(pmp->pm_devvp, de_bn2kb(pmp, bn), bsize,
+ 0, 0);
+ if (bp == NULL) {
+ /*
+ * getblk() above returns NULL only iff we are
+ * pagedaemon. See the implementation of getblk
+ * for detail.
+ */
+ return ENOMEM;
+ }
+ if (!ISSET(bp->b_oflags, (BO_DONE | BO_DELWRI))) {
+ SET(bp->b_flags, B_READ);
+ BIO_SETPRIO(bp, BPRIO_TIMECRITICAL);
+ VOP_STRATEGY(pmp->pm_devvp, bp);
+ curlwp->l_ru.ru_inblock++;
+ error = biowait(bp);
+ if (error) {
+ brelse(bp, 0);
+ return error;
+ }
}
bp_bn = bn;
}
