Date: Thu, 19 Aug 1999 14:46:01 -0700 (PDT) From: Julian Elischer <julian@whistle.com> To: fs@freebsd.org Subject: BUG in 3.2 fsck! (fwd) Message-ID: <Pine.BSF.3.95.990819144407.13522H-100000@current1.whistle.com>
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FS types..
thoughts?
An ex collegue writes to me:
-------------------------------------------
I have created and am testing an fsck version which will make lost+found much
larger (until it fills the first indirect disk page) and which has the ability
to suppress output for errors fixed by preen (which is not exactly what I
proposed before but which achieves the same end with less code and less risk).
It isn't really time yet to discuss merging these features into freeBSD, but I
think that day will come. What this mail is really about is a bug in fsck. I
am not currently competent to submit the fix or to even be positive that the
bug is current. I think this is a potentially serious bug in the current
sources. Are you interested?
BUG IN FSCK:
When the 3.2 version of fsck has to create the lost+found directory, it may
fail to flag the appropriate inode busy!
Patch: mkdir lost+found in the root directory of all your file systems.
Discussion: fsck allocates only enough space to keep track of the first inodes
in each cylinder group. This is clever and good - inode usage tends to occur
at the front of the cylinder group and this saves space. Unfortunately, it
does not work out well when a directory is created which increases the highest
inode number for the cylinder group - the inode usage doesn't get recorded in
the right place and the inode will be flagged available during pass 5.
Fix: The code change causes fsck to check the cylinder group allocation when
adding an inode and expand the inode list for the cylinder group if necessary.
In inode.c::allocino (near line 605):
for (ino = request; ino < maxino; ino++)
if (inoinfo(ino)->ino_state == USTATE)
break;
if (ino == maxino)
return (0);
inoallocinfo (ino); **** one new line of code.
In fsck.h, add the prototype for the new function inoallocinfo.
In utility.c (near line 138), replace the function inoinfo with the following:
static struct inostat unallocated = { USTATE, 0, 0 };
/*
* Look up state information for an inode.
*/
struct inostat *
inoinfo(inum)
ino_t inum;
{
struct inostatlist *ilp;
int iloff;
if (inum > maxino)
errx(EEXIT, "inoinfo: inumber %d out of range", inum);
ilp = &inostathead[inum / sblock.fs_ipg];
iloff = inum % sblock.fs_ipg;
if (iloff >= ilp->il_numalloced)
return (&unallocated);
return (&ilp->il_stat[iloff]);
}
/*
* Make it safe to allocate this inode!
*/
void
inoallocinfo (inum)
ino_t inum;
{
struct inostat *info;
struct inostatlist *ilp;
unsigned i, iloff;
if (inum > maxino)
errx(EEXIT, "inoinfo: inumber %d out of range", inum);
ilp = &inostathead[inum / sblock.fs_ipg];
iloff = inum % sblock.fs_ipg;
if (iloff >= (unsigned)ilp->il_numalloced) {
info = calloc (iloff + 1, sizeof *info);
if (info == NULL)
errx(EEXIT, "cannot alloc %u bytes for inoinfo\n",
(unsigned)(sizeof *info * (iloff + 1)));
memmove (info, ilp->il_stat, ilp->il_numalloced * sizeof *info);
free(ilp->il_stat);
ilp->il_stat = info;
for (i = ilp->il_numalloced; i <= iloff; ++i)
memmove (info + i, &unallocated, sizeof unallocated);
ilp->il_numalloced = iloff + 1;
}
}
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