[src/trunk]: src/sys/fs/nilfs Fix serious file read problem due to not-so-cle...

[reinoud <reinoud%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/06803ae397c3
branches:  trunk
changeset: 786742:06803ae397c3
user:      reinoud <reinoud%NetBSD.org@localhost>
date:      Wed May 08 10:29:22 2013 +0000

description:
Fix serious file read problem due to not-so-clear VOP_BMAP description. Should
fix PR 45605.

diffstat:

 sys/fs/nilfs/nilfs_vnops.c |  12 +++++++++---
 1 files changed, 9 insertions(+), 3 deletions(-)

diffs (40 lines):

diff -r 1e8c1b55900b -r 06803ae397c3 sys/fs/nilfs/nilfs_vnops.c
--- a/sys/fs/nilfs/nilfs_vnops.c        Wed May 08 08:57:45 2013 +0000
+++ b/sys/fs/nilfs/nilfs_vnops.c        Wed May 08 10:29:22 2013 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: nilfs_vnops.c,v 1.21 2013/03/18 19:35:38 plunky Exp $ */
+/* $NetBSD: nilfs_vnops.c,v 1.22 2013/05/08 10:29:22 reinoud Exp $ */
 
 /*
  * Copyright (c) 2008, 2009 Reinoud Zandijk
@@ -28,7 +28,7 @@
 
 #include <sys/cdefs.h>
 #ifndef lint
-__KERNEL_RCSID(0, "$NetBSD: nilfs_vnops.c,v 1.21 2013/03/18 19:35:38 plunky Exp $");
+__KERNEL_RCSID(0, "$NetBSD: nilfs_vnops.c,v 1.22 2013/05/08 10:29:22 reinoud Exp $");
 #endif /* not lint */
 
 
@@ -315,6 +315,11 @@
 /*
  * bmap functionality that translates logical block numbers to the virtual
  * block numbers to be stored on the vnode itself.
+ *
+ * Important allert!
+ *
+ * If runp is not NULL, the number of contiguous blocks __starting from the
+ * next block after the queried block__ will be returned in runp.
  */
 
 int
@@ -364,7 +369,8 @@
        run = 1;
        while ((run < blks) && (l2vmap[run] == *bnp + run))
                run++;
-       
+       run--;  /* see comment at start of function */
+
        /* set runlength */
        if (runp)
                *runp = run;