Date: Thu, 24 Feb 2011 12:16:46 +0800 From: gnehzuil <gnehzuil@gmail.com> To: John Baldwin <jhb@freebsd.org> Cc: "Pedro F. Giffuni" <giffunip@yahoo.com>, fs@freebsd.org Subject: Re: Simple ext2fs allocation routine cleanups Message-ID: <4D65DBAE.7010505@gmail.com> In-Reply-To: <201102231432.38902.jhb@freebsd.org> References: <201102230811.32864.jhb@freebsd.org> <AANLkTinrMSSCrwuAtzrgNOjpV=5OpH68zOY2Lkingc7R@mail.gmail.com> <201102231432.38902.jhb@freebsd.org>
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Hi John,
I have tried your changes again. It's ok. The error doesn't occurred. I
think the problem is off-by-one bug.
Best regards,
lz
On 02/24/2011 03:32 AM, John Baldwin wrote:
> On Wednesday, February 23, 2011 11:35:33 am gnehzuil gnehzuil wrote:
>> Hi John,
>>
>> I use dbench program to do some tests for your changes. However, it causes
>> kernel crash. The error is as follows:
>>
>> panic: __lockmgr_args: recursing on non recursive lockmgr ext2fs @
>> /usr/src/sys/kern/vfs_subr.c:2124
> I wasn't able to reproduce that, but I did have silly off-by-one bugs in the
> use of ffs() that should be fixed now:
>
> Index: ext2_alloc.c
> ===================================================================
> --- ext2_alloc.c (revision 218975)
> +++ ext2_alloc.c (working copy)
> @@ -815,16 +815,12 @@ ext2_nodealloccg(struct inode *ip, int cg, daddr_t
> }
> }
> i = start + len - loc;
> - map = ibp[i];
> - ipref = i * NBBY;
> - for (i = 1; i< (1<< NBBY); i<<= 1, ipref++) {
> - if ((map& i) == 0) {
> - goto gotit;
> - }
> + map = ibp[i] ^ 0xff;
> + if (map == 0) {
> + printf("fs = %s\n", fs->e2fs_fsmnt);
> + panic("ext2fs_nodealloccg: block not in map");
> }
> - printf("fs = %s\n", fs->e2fs_fsmnt);
> - panic("ext2fs_nodealloccg: block not in map");
> - /* NOTREACHED */
> + ipref = i * NBBY + ffs(map) - 1;
> gotit:
> setbit(ibp, ipref);
> EXT2_LOCK(ump);
> @@ -952,7 +948,6 @@ ext2_vfree(pvp, ino, mode)
> static daddr_t
> ext2_mapsearch(struct m_ext2fs *fs, char *bbp, daddr_t bpref)
> {
> - daddr_t bno;
> int start, len, loc, i, map;
>
> /*
> @@ -977,15 +972,12 @@ ext2_mapsearch(struct m_ext2fs *fs, char *bbp, dad
> }
> }
> i = start + len - loc;
> - map = bbp[i];
> - bno = i * NBBY;
> - for (i = 1; i< (1<< NBBY); i<<= 1, bno++) {
> - if ((map& i) == 0)
> - return (bno);
> + map = bbp[i] ^ 0xff;
> + if (map == 0) {
> + printf("fs = %s\n", fs->e2fs_fsmnt);
> + panic("ext2fs_mapsearch: block not in map");
> }
> - printf("fs = %s\n", fs->e2fs_fsmnt);
> - panic("ext2fs_mapsearch: block not in map");
> - /* NOTREACHED */
> + return (i * NBBY + ffs(map) - 1);
> }
>
> /*
>
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