kern/85503: panic: wrong dirclust using msdosfs in RELENG_6

From: Dmitry Pryanishnikov (dmitry_at_atlantis.dp.ua)
Date: 09/01/05

  • Next message: Bruce Evans: "Re: kern/85503: panic: wrong dirclust using msdosfs in RELENG_6" 
    Date: Thu, 1 Sep 2005 11:56:06 +0300 (EEST)
To: freebsd-arch@freebsd.org

    Hello!

      During the hunting the bug kern/85503 (panic: wrong dirclust in msdosfs)
    I've tried to think about the solution, but it seems to be
    architecture-related. The problem is: msdosfs uses pseudo-inodes (that is,
    the offset from the start of the partition to the start of directory entry
    in bytes) which must therefore have off_t bitness (at least 64 bits). I've
    found the primary error (lack of casts leaded to 32-bit result), but then
    we should transfer this 64-bit "inode" number to vfs_hash_get(). Oops,
    it also limited to u_int (32 bits on i386). Finally, I see that the
    primary shortcoming here: in sys/vnode.h we have

             /*
              * vfs_hash: (mount + inode) -> vnode hash.
              */
             LIST_ENTRY(vnode) v_hashlist;
             u_int v_hash;

    I think it's feasible and useful to upgrade type of v_hash to at least off_t.
    In our days of large media we will face filesystems with more than 4 billions
    files (and thus at least 64-bit inode numbers) quite often. Am I right?

    Sincerely, Dmitry 

    -- 
Atlantis ISP, System Administrator
e-mail:  dmitry@atlantis.dp.ua
nic-hdl: LYNX-RIPE
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  • Next message: Bruce Evans: "Re: kern/85503: panic: wrong dirclust using msdosfs in RELENG_6"

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