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Quick fix for non-unique inode numbers for hard links. We use the

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byte offset of the directory entry for the inode number for all types
of files except directories, although this breaks hard links for
non-directories even if it doesn't cause overflow.  Just ignore this
broken inode number for stat() and readdir() and return a less broken
one (the block offset of the file), so that applications normally can't
see the brokenness.

This leaves at least the following brokenness:
- extra inodes, vnodes and caching for hard links.
- various overflow bugs.  cd9660 supports 64-bit block numbers, but we
  silently ignore the top 32 bits in isonum_733() and then drop another
  10 bits for our broken inode numbers.  We may also have sign extension
  bugs from storing 32-bit extents in ints and longs even if ints are
  32-bits.  These bugs affect DVDs.  mkisofs apparently limits them
  by writing directory entries first.

Inode numbers were broken mainly in 4.4BSD-Lite2.  FreeBSD-1.1.5 seems
to have a correct implementation modulo the overflow bugs.  We need
to look up directory entries from inodes for symlinks only.  FreeBSD-1.1.5
use separate fields (iso_parent_extent, iso_parent) to point to the
directory entry.  4.4BSD-Lite doesn't have these, and abuses i_ino to
point to the directory entry.  Correct pointers are impossible for
hard links, but symlinks can't be hard links.
This commit is contained in:
bde 2002-05-22 08:50:18 +00:00
parent 69b9569958
commit ac874d558b
2 changed files with 28 additions and 12 deletions
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20
sys/fs/cd9660/cd9660_vnops.c
View File

@ -170,7 +170,14 @@ cd9660_getattr(ap)
register struct iso_node *ip = VTOI(vp);
vap->va_fsid = dev2udev(ip->i_dev);
vap->va_fileid = ip->i_number;
/*
* Don't use ip->i_ino for this since it is wrong for hard links.
* ip->i_ino should be the same as ip->iso_start (or not exist),
* but this currently doesn't work since we abuse it to look up
* parent directories from inodes.
*/
vap->va_fileid = ip->iso_start;
vap->va_mode = ip->inode.iso_mode;
vap->va_nlink = ip->inode.iso_links;
@ -524,11 +531,12 @@ cd9660_readdir(ap)
break;
}
if (isonum_711(ep->flags)&2)
idp->current.d_fileno = isodirino(ep, imp);
else
idp->current.d_fileno = dbtob(bp->b_blkno) +
entryoffsetinblock;
/*
* The "inode number" is iso_start, not i_ino, as in
* cd9660_getattr().
*/
idp->current.d_fileno = isonum_711(ep->ext_attr_length) +
isonum_733(ep->extent);
idp->curroff += reclen;

20
sys/isofs/cd9660/cd9660_vnops.c
View File

@ -170,7 +170,14 @@ cd9660_getattr(ap)
register struct iso_node *ip = VTOI(vp);
vap->va_fsid = dev2udev(ip->i_dev);
vap->va_fileid = ip->i_number;
/*
* Don't use ip->i_ino for this since it is wrong for hard links.
* ip->i_ino should be the same as ip->iso_start (or not exist),
* but this currently doesn't work since we abuse it to look up
* parent directories from inodes.
*/
vap->va_fileid = ip->iso_start;
vap->va_mode = ip->inode.iso_mode;
vap->va_nlink = ip->inode.iso_links;
@ -524,11 +531,12 @@ cd9660_readdir(ap)
break;
}
if (isonum_711(ep->flags)&2)
idp->current.d_fileno = isodirino(ep, imp);
else
idp->current.d_fileno = dbtob(bp->b_blkno) +
entryoffsetinblock;
/*
* The "inode number" is iso_start, not i_ino, as in
* cd9660_getattr().
*/
idp->current.d_fileno = isonum_711(ep->ext_attr_length) +
isonum_733(ep->extent);
idp->curroff += reclen;