Date: Thu, 27 Dec 2001 02:34:40 -0600 (CST) From: Kevin Day <toasty@temphost.dragondata.com> To: hackers@freebsd.org Subject: signedness in fsck Message-ID: <200112270834.fBR8YfD13572@temphost.dragondata.com>
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I think I've found a bug in fsck. Some invalid values in cylinder groups
don't get fixed.
From pass5.c:
if (cg->cg_rotor < newcg->cg_ndblk)
newcg->cg_rotor = cg->cg_rotor;
else
newcg->cg_rotor = 0;
if (cg->cg_frotor < newcg->cg_ndblk)
newcg->cg_frotor = cg->cg_frotor;
else
newcg->cg_frotor = 0;
if (cg->cg_irotor < newcg->cg_niblk)
newcg->cg_irotor = cg->cg_irotor;
else
newcg->cg_irotor = 0;
All those values in the cg's are int32_t's. (signed). Somehow I ended up
with 5 cyl groups that have "irotor" to some random negative value. fsck
doesn't see a problem with them, but I get a panic when a create gets
called:
#5 0xc0207e6b in trap (frame={tf_fs = -1072234480, tf_es = -345702384, tf_ds = -1072234480, tf_edi = -750092288, tf_esi = -955801600,
tf_ebp = -345663052, tf_isp = -345663072, tf_ebx = 177188131, tf_edx = -750091519, tf_ecx = 255, tf_eax = -927279650, tf_trapno = 12,
tf_err = 0, tf_eip = -1071824083, tf_cs = 8, tf_eflags = 66183, tf_esp = -345663008, tf_ss = -1071971432}) at ../../i386/i386/trap.c:448
#6 0xc01d432d in skpc (mask0=255, size=177188131, cp0=0xc8bad5de <Address 0xc8bad5de out of bounds>) at ../../libkern/skpc.c:50
#7 0xc01b0398 in ffs_nodealloccg (ip=0xc7cb6300, cg=6921, ipref=27906609, mode=33188) at ../../ufs/ffs/ffs_alloc.c:1347
#8 0xc01af567 in ffs_hashalloc (ip=0xc7cb6300, cg=6921, pref=27906609, size=33188, allocator=0xc01b0258 <ffs_nodealloccg>)
at ../../ufs/ffs/ffs_alloc.c:863
#9 0xc01aeffc in ffs_valloc (pvp=0xebe8d980, mode=33188, cred=0xc77fd584, vpp=0xeb659a5c) at ../../ufs/ffs/ffs_alloc.c:607
#10 0xc01c1b0f in ufs_makeinode (mode=33188, dvp=0xebe8d980, vpp=0xeb659c64, cnp=0xeb659c78) at ../../ufs/ufs/ufs_vnops.c:2097
#11 0xc01bf4c4 in ufs_create (ap=0xeb659bfc) at ../../ufs/ufs/ufs_vnops.c:194
Here's the cyl group:
$2 = {cg_firstfield = 0, cg_magic = 590421, cg_time = 1009434417, cg_cgx = 9165, cg_ncyl = 16, cg_niblk = 4032, cg_ndblk = 32768, cg_cs = {
cs_ndir = 60, cs_nbfree = 2740, cs_nifree = 1987, cs_nffree = 679}, cg_rotor = 1288, cg_frotor = 5112, cg_irotor = -2036988557,
cg_frsum = {0, 80, 153, 45, 14, 5, 7, 5}, cg_btotoff = 168, cg_boff = 232, cg_iusedoff = 264, cg_freeoff = 768, cg_nextfreeoff = 5436,
cg_clustersumoff = 4860, cg_clusteroff = 4924, cg_nclusterblks = 4096, cg_sparecon = {0 <repeats 13 times>}, cg_space = "\016"}
Notice cg_irotor is completely out of whack, but fsck thinks the FS is
clean.
I wrote a patch that made fsck detect this, but... why are these signed
values anyway, other than historical reasons?
-- Kevin
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