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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * namei.c - NTFS kernel directory inode operations. Part of the Linux-NTFS
3 * project.
4 *
Anton Altaparmakov67b1dfe2006-03-23 14:57:43 +00005 * Copyright (c) 2001-2006 Anton Altaparmakov
Linus Torvalds1da177e2005-04-16 15:20:36 -07006 *
7 * This program/include file is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License as published
9 * by the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
11 *
12 * This program/include file is distributed in the hope that it will be
13 * useful, but WITHOUT ANY WARRANTY; without even the implied warranty
14 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with this program (in the main directory of the Linux-NTFS
19 * distribution in the file COPYING); if not, write to the Free Software
20 * Foundation,Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
21 */
22
23#include <linux/dcache.h>
Christoph Hellwiga5694252007-07-17 04:04:28 -070024#include <linux/exportfs.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070025#include <linux/security.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090026#include <linux/slab.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070027
28#include "attrib.h"
29#include "debug.h"
30#include "dir.h"
31#include "mft.h"
32#include "ntfs.h"
33
34/**
35 * ntfs_lookup - find the inode represented by a dentry in a directory inode
36 * @dir_ino: directory inode in which to look for the inode
37 * @dent: dentry representing the inode to look for
38 * @nd: lookup nameidata
39 *
40 * In short, ntfs_lookup() looks for the inode represented by the dentry @dent
41 * in the directory inode @dir_ino and if found attaches the inode to the
42 * dentry @dent.
43 *
44 * In more detail, the dentry @dent specifies which inode to look for by
45 * supplying the name of the inode in @dent->d_name.name. ntfs_lookup()
46 * converts the name to Unicode and walks the contents of the directory inode
47 * @dir_ino looking for the converted Unicode name. If the name is found in the
48 * directory, the corresponding inode is loaded by calling ntfs_iget() on its
49 * inode number and the inode is associated with the dentry @dent via a call to
50 * d_splice_alias().
51 *
52 * If the name is not found in the directory, a NULL inode is inserted into the
53 * dentry @dent via a call to d_add(). The dentry is then termed a negative
54 * dentry.
55 *
56 * Only if an actual error occurs, do we return an error via ERR_PTR().
57 *
58 * In order to handle the case insensitivity issues of NTFS with regards to the
59 * dcache and the dcache requiring only one dentry per directory, we deal with
60 * dentry aliases that only differ in case in ->ntfs_lookup() while maintaining
61 * a case sensitive dcache. This means that we get the full benefit of dcache
62 * speed when the file/directory is looked up with the same case as returned by
63 * ->ntfs_readdir() but that a lookup for any other case (or for the short file
64 * name) will not find anything in dcache and will enter ->ntfs_lookup()
65 * instead, where we search the directory for a fully matching file name
66 * (including case) and if that is not found, we search for a file name that
67 * matches with different case and if that has non-POSIX semantics we return
68 * that. We actually do only one search (case sensitive) and keep tabs on
69 * whether we have found a case insensitive match in the process.
70 *
71 * To simplify matters for us, we do not treat the short vs long filenames as
72 * two hard links but instead if the lookup matches a short filename, we
73 * return the dentry for the corresponding long filename instead.
74 *
75 * There are three cases we need to distinguish here:
76 *
77 * 1) @dent perfectly matches (i.e. including case) a directory entry with a
78 * file name in the WIN32 or POSIX namespaces. In this case
79 * ntfs_lookup_inode_by_name() will return with name set to NULL and we
80 * just d_splice_alias() @dent.
81 * 2) @dent matches (not including case) a directory entry with a file name in
82 * the WIN32 namespace. In this case ntfs_lookup_inode_by_name() will return
83 * with name set to point to a kmalloc()ed ntfs_name structure containing
84 * the properly cased little endian Unicode name. We convert the name to the
85 * current NLS code page, search if a dentry with this name already exists
86 * and if so return that instead of @dent. At this point things are
87 * complicated by the possibility of 'disconnected' dentries due to NFS
88 * which we deal with appropriately (see the code comments). The VFS will
89 * then destroy the old @dent and use the one we returned. If a dentry is
90 * not found, we allocate a new one, d_splice_alias() it, and return it as
91 * above.
92 * 3) @dent matches either perfectly or not (i.e. we don't care about case) a
93 * directory entry with a file name in the DOS namespace. In this case
94 * ntfs_lookup_inode_by_name() will return with name set to point to a
95 * kmalloc()ed ntfs_name structure containing the mft reference (cpu endian)
96 * of the inode. We use the mft reference to read the inode and to find the
97 * file name in the WIN32 namespace corresponding to the matched short file
98 * name. We then convert the name to the current NLS code page, and proceed
99 * searching for a dentry with this name, etc, as in case 2), above.
100 *
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800101 * Locking: Caller must hold i_mutex on the directory.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700102 */
103static struct dentry *ntfs_lookup(struct inode *dir_ino, struct dentry *dent,
Al Viro00cd8dd2012-06-10 17:13:09 -0400104 unsigned int flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700105{
106 ntfs_volume *vol = NTFS_SB(dir_ino->i_sb);
107 struct inode *dent_inode;
108 ntfschar *uname;
109 ntfs_name *name = NULL;
110 MFT_REF mref;
111 unsigned long dent_ino;
112 int uname_len;
113
114 ntfs_debug("Looking up %s in directory inode 0x%lx.",
115 dent->d_name.name, dir_ino->i_ino);
116 /* Convert the name of the dentry to Unicode. */
117 uname_len = ntfs_nlstoucs(vol, dent->d_name.name, dent->d_name.len,
118 &uname);
119 if (uname_len < 0) {
Anton Altaparmakov834ba602006-03-23 16:25:23 +0000120 if (uname_len != -ENAMETOOLONG)
121 ntfs_error(vol->sb, "Failed to convert name to "
122 "Unicode.");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700123 return ERR_PTR(uname_len);
124 }
125 mref = ntfs_lookup_inode_by_name(NTFS_I(dir_ino), uname, uname_len,
126 &name);
127 kmem_cache_free(ntfs_name_cache, uname);
128 if (!IS_ERR_MREF(mref)) {
129 dent_ino = MREF(mref);
130 ntfs_debug("Found inode 0x%lx. Calling ntfs_iget.", dent_ino);
131 dent_inode = ntfs_iget(vol->sb, dent_ino);
132 if (likely(!IS_ERR(dent_inode))) {
133 /* Consistency check. */
134 if (is_bad_inode(dent_inode) || MSEQNO(mref) ==
135 NTFS_I(dent_inode)->seq_no ||
136 dent_ino == FILE_MFT) {
137 /* Perfect WIN32/POSIX match. -- Case 1. */
138 if (!name) {
139 ntfs_debug("Done. (Case 1.)");
140 return d_splice_alias(dent_inode, dent);
141 }
142 /*
143 * We are too indented. Handle imperfect
144 * matches and short file names further below.
145 */
146 goto handle_name;
147 }
148 ntfs_error(vol->sb, "Found stale reference to inode "
149 "0x%lx (reference sequence number = "
150 "0x%x, inode sequence number = 0x%x), "
151 "returning -EIO. Run chkdsk.",
152 dent_ino, MSEQNO(mref),
153 NTFS_I(dent_inode)->seq_no);
154 iput(dent_inode);
155 dent_inode = ERR_PTR(-EIO);
156 } else
157 ntfs_error(vol->sb, "ntfs_iget(0x%lx) failed with "
158 "error code %li.", dent_ino,
159 PTR_ERR(dent_inode));
Jesper Juhl251c8422005-04-04 14:59:56 +0100160 kfree(name);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700161 /* Return the error code. */
162 return (struct dentry *)dent_inode;
163 }
Anton Altaparmakov834ba602006-03-23 16:25:23 +0000164 /* It is guaranteed that @name is no longer allocated at this point. */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700165 if (MREF_ERR(mref) == -ENOENT) {
166 ntfs_debug("Entry was not found, adding negative dentry.");
167 /* The dcache will handle negative entries. */
168 d_add(dent, NULL);
169 ntfs_debug("Done.");
170 return NULL;
171 }
172 ntfs_error(vol->sb, "ntfs_lookup_ino_by_name() failed with error "
173 "code %i.", -MREF_ERR(mref));
174 return ERR_PTR(MREF_ERR(mref));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700175 // TODO: Consider moving this lot to a separate function! (AIA)
176handle_name:
177 {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700178 MFT_RECORD *m;
179 ntfs_attr_search_ctx *ctx;
180 ntfs_inode *ni = NTFS_I(dent_inode);
181 int err;
182 struct qstr nls_name;
183
184 nls_name.name = NULL;
185 if (name->type != FILE_NAME_DOS) { /* Case 2. */
186 ntfs_debug("Case 2.");
187 nls_name.len = (unsigned)ntfs_ucstonls(vol,
188 (ntfschar*)&name->name, name->len,
189 (unsigned char**)&nls_name.name, 0);
190 kfree(name);
191 } else /* if (name->type == FILE_NAME_DOS) */ { /* Case 3. */
192 FILE_NAME_ATTR *fn;
193
194 ntfs_debug("Case 3.");
195 kfree(name);
196
197 /* Find the WIN32 name corresponding to the matched DOS name. */
198 ni = NTFS_I(dent_inode);
199 m = map_mft_record(ni);
200 if (IS_ERR(m)) {
201 err = PTR_ERR(m);
202 m = NULL;
203 ctx = NULL;
204 goto err_out;
205 }
206 ctx = ntfs_attr_get_search_ctx(ni, m);
207 if (unlikely(!ctx)) {
208 err = -ENOMEM;
209 goto err_out;
210 }
211 do {
212 ATTR_RECORD *a;
213 u32 val_len;
214
215 err = ntfs_attr_lookup(AT_FILE_NAME, NULL, 0, 0, 0,
216 NULL, 0, ctx);
217 if (unlikely(err)) {
218 ntfs_error(vol->sb, "Inode corrupt: No WIN32 "
219 "namespace counterpart to DOS "
220 "file name. Run chkdsk.");
221 if (err == -ENOENT)
222 err = -EIO;
223 goto err_out;
224 }
225 /* Consistency checks. */
226 a = ctx->attr;
227 if (a->non_resident || a->flags)
228 goto eio_err_out;
229 val_len = le32_to_cpu(a->data.resident.value_length);
230 if (le16_to_cpu(a->data.resident.value_offset) +
231 val_len > le32_to_cpu(a->length))
232 goto eio_err_out;
233 fn = (FILE_NAME_ATTR*)((u8*)ctx->attr + le16_to_cpu(
234 ctx->attr->data.resident.value_offset));
235 if ((u32)(fn->file_name_length * sizeof(ntfschar) +
236 sizeof(FILE_NAME_ATTR)) > val_len)
237 goto eio_err_out;
238 } while (fn->file_name_type != FILE_NAME_WIN32);
239
240 /* Convert the found WIN32 name to current NLS code page. */
241 nls_name.len = (unsigned)ntfs_ucstonls(vol,
242 (ntfschar*)&fn->file_name, fn->file_name_length,
243 (unsigned char**)&nls_name.name, 0);
244
245 ntfs_attr_put_search_ctx(ctx);
246 unmap_mft_record(ni);
247 }
248 m = NULL;
249 ctx = NULL;
250
251 /* Check if a conversion error occurred. */
252 if ((signed)nls_name.len < 0) {
253 err = (signed)nls_name.len;
254 goto err_out;
255 }
256 nls_name.hash = full_name_hash(nls_name.name, nls_name.len);
257
Christoph Hellwig26904212008-08-07 23:50:21 +0200258 dent = d_add_ci(dent, dent_inode, &nls_name);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700259 kfree(nls_name.name);
Christoph Hellwig26904212008-08-07 23:50:21 +0200260 return dent;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700261
262eio_err_out:
263 ntfs_error(vol->sb, "Illegal file name attribute. Run chkdsk.");
264 err = -EIO;
265err_out:
266 if (ctx)
267 ntfs_attr_put_search_ctx(ctx);
268 if (m)
269 unmap_mft_record(ni);
270 iput(dent_inode);
271 ntfs_error(vol->sb, "Failed, returning error code %i.", err);
272 return ERR_PTR(err);
273 }
274}
275
276/**
277 * Inode operations for directories.
278 */
Arjan van de Ven92e1d5b2007-02-12 00:55:39 -0800279const struct inode_operations ntfs_dir_inode_ops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700280 .lookup = ntfs_lookup, /* VFS: Lookup directory. */
281};
282
283/**
284 * ntfs_get_parent - find the dentry of the parent of a given directory dentry
285 * @child_dent: dentry of the directory whose parent directory to find
286 *
287 * Find the dentry for the parent directory of the directory specified by the
288 * dentry @child_dent. This function is called from
289 * fs/exportfs/expfs.c::find_exported_dentry() which in turn is called from the
290 * default ->decode_fh() which is export_decode_fh() in the same file.
291 *
292 * The code is based on the ext3 ->get_parent() implementation found in
293 * fs/ext3/namei.c::ext3_get_parent().
294 *
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800295 * Note: ntfs_get_parent() is called with @child_dent->d_inode->i_mutex down.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700296 *
297 * Return the dentry of the parent directory on success or the error code on
298 * error (IS_ERR() is true).
299 */
Anton Altaparmakov41382682005-03-03 13:44:15 +0000300static struct dentry *ntfs_get_parent(struct dentry *child_dent)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700301{
302 struct inode *vi = child_dent->d_inode;
303 ntfs_inode *ni = NTFS_I(vi);
304 MFT_RECORD *mrec;
305 ntfs_attr_search_ctx *ctx;
306 ATTR_RECORD *attr;
307 FILE_NAME_ATTR *fn;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700308 unsigned long parent_ino;
309 int err;
310
311 ntfs_debug("Entering for inode 0x%lx.", vi->i_ino);
312 /* Get the mft record of the inode belonging to the child dentry. */
313 mrec = map_mft_record(ni);
314 if (IS_ERR(mrec))
315 return (struct dentry *)mrec;
316 /* Find the first file name attribute in the mft record. */
317 ctx = ntfs_attr_get_search_ctx(ni, mrec);
318 if (unlikely(!ctx)) {
319 unmap_mft_record(ni);
320 return ERR_PTR(-ENOMEM);
321 }
322try_next:
323 err = ntfs_attr_lookup(AT_FILE_NAME, NULL, 0, CASE_SENSITIVE, 0, NULL,
324 0, ctx);
325 if (unlikely(err)) {
326 ntfs_attr_put_search_ctx(ctx);
327 unmap_mft_record(ni);
328 if (err == -ENOENT)
329 ntfs_error(vi->i_sb, "Inode 0x%lx does not have a "
330 "file name attribute. Run chkdsk.",
331 vi->i_ino);
332 return ERR_PTR(err);
333 }
334 attr = ctx->attr;
335 if (unlikely(attr->non_resident))
336 goto try_next;
337 fn = (FILE_NAME_ATTR *)((u8 *)attr +
338 le16_to_cpu(attr->data.resident.value_offset));
339 if (unlikely((u8 *)fn + le32_to_cpu(attr->data.resident.value_length) >
340 (u8*)attr + le32_to_cpu(attr->length)))
341 goto try_next;
342 /* Get the inode number of the parent directory. */
343 parent_ino = MREF_LE(fn->parent_directory);
344 /* Release the search context and the mft record of the child. */
345 ntfs_attr_put_search_ctx(ctx);
346 unmap_mft_record(ni);
Christoph Hellwig44003722008-08-11 15:49:04 +0200347
348 return d_obtain_alias(ntfs_iget(vi->i_sb, parent_ino));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700349}
350
Christoph Hellwiga3513202007-10-21 16:42:10 -0700351static struct inode *ntfs_nfs_get_inode(struct super_block *sb,
352 u64 ino, u32 generation)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700353{
Christoph Hellwiga3513202007-10-21 16:42:10 -0700354 struct inode *inode;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700355
Christoph Hellwiga3513202007-10-21 16:42:10 -0700356 inode = ntfs_iget(sb, ino);
357 if (!IS_ERR(inode)) {
358 if (is_bad_inode(inode) || inode->i_generation != generation) {
359 iput(inode);
360 inode = ERR_PTR(-ESTALE);
361 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700362 }
Christoph Hellwiga3513202007-10-21 16:42:10 -0700363
364 return inode;
365}
366
367static struct dentry *ntfs_fh_to_dentry(struct super_block *sb, struct fid *fid,
368 int fh_len, int fh_type)
369{
370 return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
371 ntfs_nfs_get_inode);
372}
373
374static struct dentry *ntfs_fh_to_parent(struct super_block *sb, struct fid *fid,
375 int fh_len, int fh_type)
376{
377 return generic_fh_to_parent(sb, fid, fh_len, fh_type,
378 ntfs_nfs_get_inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700379}
Anton Altaparmakov41382682005-03-03 13:44:15 +0000380
381/**
382 * Export operations allowing NFS exporting of mounted NTFS partitions.
383 *
Christoph Hellwiga3513202007-10-21 16:42:10 -0700384 * We use the default ->encode_fh() for now. Note that they
Anton Altaparmakov41382682005-03-03 13:44:15 +0000385 * use 32 bits to store the inode number which is an unsigned long so on 64-bit
386 * architectures is usually 64 bits so it would all fail horribly on huge
387 * volumes. I guess we need to define our own encode and decode fh functions
388 * that store 64-bit inode numbers at some point but for now we will ignore the
389 * problem...
390 *
391 * We also use the default ->get_name() helper (used by ->decode_fh() via
392 * fs/exportfs/expfs.c::find_exported_dentry()) as that is completely fs
393 * independent.
394 *
395 * The default ->get_parent() just returns -EACCES so we have to provide our
396 * own and the default ->get_dentry() is incompatible with NTFS due to not
397 * allowing the inode number 0 which is used in NTFS for the system file $MFT
398 * and due to using iget() whereas NTFS needs ntfs_iget().
399 */
Christoph Hellwig39655162007-10-21 16:42:17 -0700400const struct export_operations ntfs_export_ops = {
Anton Altaparmakov41382682005-03-03 13:44:15 +0000401 .get_parent = ntfs_get_parent, /* Find the parent of a given
402 directory. */
Christoph Hellwiga3513202007-10-21 16:42:10 -0700403 .fh_to_dentry = ntfs_fh_to_dentry,
404 .fh_to_parent = ntfs_fh_to_parent,
Anton Altaparmakov41382682005-03-03 13:44:15 +0000405};