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From: Yura P. <y.p...@sa...> - 2005-09-30 12:55:55
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=D0=92 =D0=9F=D1=82=D0=BD, 30/09/2005 =D0=B2 13:30 +0100, Anton Altaparmako=
v =D0=BF=D0=B8=D1=88=D0=B5=D1=82:
> On Fri, 2005-09-30 at 14:46 +0300, Yura Pakhuchiy wrote:
> > =D0=92 =D0=9F=D1=82=D0=BD, 30/09/2005 =D0=B2 11:02 +0100, Anton Altapar=
makov =D0=BF=D0=B8=D1=88=D0=B5=D1=82:
> > > > --- attrib.c 28 Sep 2005 13:47:47 -0000 1.178
> > > > +++ attrib.c 30 Sep 2005 09:52:05 -0000 1.179
> > > > @@ -2554,7 +2554,7 @@ int ntfs_resident_attr_record_add(ntfs_i
> > > > }
> > > > =20
> > > > /* Locate place where record should be. */
> > > > - ctx =3D ntfs_attr_get_search_ctx(ni, NULL);
> > > > + ctx =3D ntfs_attr_get_search_ctx(NULL, ni->mrec);
> > > > if (!ctx)
> > > > return -1;
> > > > if (!ntfs_attr_lookup(type, name, name_len,
> > > > @@ -2679,7 +2679,7 @@ int ntfs_non_resident_attr_record_add(nt
> > > > }
> > > > =20
> > > > /* Locate place where record should be. */
> > > > - ctx =3D ntfs_attr_get_search_ctx(ni, NULL);
> > > > + ctx =3D ntfs_attr_get_search_ctx(NULL, ni->mrec);
> > > > if (!ctx)
> > > > return -1;
> > > > if (!ntfs_attr_lookup(type, name, name_len, CASE_SENSITIVE,
> > > > @@ -3342,7 +3342,7 @@ int ntfs_attr_record_move_to(ntfs_attr_s
> > > > =20
> > > > /* Find place in MFT record where attribute will be moved. */
> > > > a =3D ctx->attr;
> > > > - nctx =3D ntfs_attr_get_search_ctx(ni, NULL);
> > > > + nctx =3D ntfs_attr_get_search_ctx(NULL, ni->mrec);
> > > > if (!nctx) {
> > > > err =3D errno;
> > > > Dprintf("%s(): Couldn't obtain search context.\n",
> > >=20
> > > The above three will now always fail when name !=3D NULL in the call =
to
> > > ntfs_attr_lookup(). You must use ntfs_attr_find() instead.
> >=20
> > Why you add such check? What problems can happen in case sensitive
> > lookup?
>=20
> You _cannot_ perform case insensitive lookup without an upcase table by
> definition of what case insensitive means. attr_find/lookup _have_ to
> do case insensitive comparison of the name. They cannot do this if no
> upcase table is present.
>=20
> As I said in earlier message the correct fix would be to add either the
> volume or the upcase table + length to somewhere, either the search
> context itself so there would be "ntfs_inode_get_search_ctx(ntfs_inode
> *ni)" and "ntfs_mft_get_search_ctx(ntfs_volume *vol, MFT_RECORD *mrec)".
> Or alternatively modify ntfs_attr_find() to also take the upcase table
> (or the volume I suppose but that will cause problems with places that
> do not have a volume) and then you can pass it in when you have acquired
> the context with (NULL, mrec)...
>=20
> Basically ntfs_attr_find() MUST AT ALL TIMES have access to upcase table
> if a name is provided for the comparisons. At present if you get a
> search context with (NULL, mrec) you do NOT have an upcase table in
> _lookup/find so they cannot execute correctly.
>=20
> Just read ntfs_attr_find():
>=20
> if (name =3D=3D AT_UNNAMED) {
> /* The search failed if the found attribute is named. */
> if (a->name_length) {
> errno =3D ENOENT;
> return -1;
> }
> } else if (name && !ntfs_names_are_equal(name, name_len,
> (ntfschar*)((char*)a + le16_to_cpu(a->name_offset)),
> a->name_length, ic, upcase, upcase_len)) {
> register int rc;
>=20
> rc =3D ntfs_names_collate(name, name_len,
> (ntfschar*)((char*)a +
> le16_to_cpu(a->name_offset)),
> a->name_length, 1, IGNORE_CASE,
> upcase, upcase_len);
>=20
>=20
> ************************************
> THIS REQUIRES UPCASE TABLE
> ************************************
>=20
>=20
> /*
> * If @name collates before a->name, there is no
> * matching attribute.
> */
> if (rc =3D=3D -1) {
> errno =3D ENOENT;
> return -1;
> }
> /* If the strings are not equal, continue search. */
> if (rc)
> continue;
> rc =3D ntfs_names_collate(name, name_len,
> (ntfschar*)((char*)a +
> le16_to_cpu(a->name_offset)),
> a->name_length, 1, CASE_SENSITIVE,
> upcase, upcase_len);
> if (rc =3D=3D -1) {
> errno =3D ENOENT;
> return -1;
> }
> if (rc)
> continue;
> }
>=20
> Sorry but which part of this do you not understand? What you were doing
> worked only by chance/accident/coincidence. It WOULD cause data
> corruption and I am not having it.
Now I understand problem, didn't thought earlier that ntfs_attr_find may
need upcase table even for case sensitive lookups. Thank you for
explanation. I commit version you proposed to use.
--=20
Cheers,
Yura
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