Date: Wed, 23 Feb 2011 21:33:25 +0800 From: gnehzuil <gnehzuil@gmail.com> To: John Baldwin <jhb@freebsd.org> Cc: freebsd-fs@freebsd.org Subject: Re: Simple ext2fs allocation routine cleanups Message-ID: <4D650CA5.4030603@gmail.com> In-Reply-To: <201102230811.32864.jhb@freebsd.org> References: <201102230811.32864.jhb@freebsd.org>
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Hi John,
I can try to do some tests. :-)
Best regards,
lz
On 02/23/2011 09:11 PM, John Baldwin wrote:
> I have some small changes to ext2fs to use ffs() to simplify some of the
> allocation routines. The changes compile, but I have not had time to generate
> a test ext2fs file system to run-test them. If someone has some spare cycles
> to setup a test file system and try them out I would appreciate it. Otherwise
> I will get to it eventually. Given that this hasn't been run-tested yet, I
> would not recommend using it for a production ext2fs since it may completely
> trash the filesystem.
>
> Index: ext2_alloc.c
> ===================================================================
> --- ext2_alloc.c (revision 218951)
> +++ ext2_alloc.c (working copy)
> @@ -815,16 +815,12 @@
> }
> }
> 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);
> gotit:
> setbit(ibp, ipref);
> EXT2_LOCK(ump);
> @@ -952,7 +948,6 @@
> 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 @@
> }
> }
> 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));
> }
>
> /*
>
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