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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>
26
27#include "attrib.h"
28#include "debug.h"
29#include "dir.h"
30#include "mft.h"
31#include "ntfs.h"
32
33/**
34 * ntfs_lookup - find the inode represented by a dentry in a directory inode
35 * @dir_ino: directory inode in which to look for the inode
36 * @dent: dentry representing the inode to look for
37 * @nd: lookup nameidata
38 *
39 * In short, ntfs_lookup() looks for the inode represented by the dentry @dent
40 * in the directory inode @dir_ino and if found attaches the inode to the
41 * dentry @dent.
42 *
43 * In more detail, the dentry @dent specifies which inode to look for by
44 * supplying the name of the inode in @dent->d_name.name. ntfs_lookup()
45 * converts the name to Unicode and walks the contents of the directory inode
46 * @dir_ino looking for the converted Unicode name. If the name is found in the
47 * directory, the corresponding inode is loaded by calling ntfs_iget() on its
48 * inode number and the inode is associated with the dentry @dent via a call to
49 * d_splice_alias().
50 *
51 * If the name is not found in the directory, a NULL inode is inserted into the
52 * dentry @dent via a call to d_add(). The dentry is then termed a negative
53 * dentry.
54 *
55 * Only if an actual error occurs, do we return an error via ERR_PTR().
56 *
57 * In order to handle the case insensitivity issues of NTFS with regards to the
58 * dcache and the dcache requiring only one dentry per directory, we deal with
59 * dentry aliases that only differ in case in ->ntfs_lookup() while maintaining
60 * a case sensitive dcache. This means that we get the full benefit of dcache
61 * speed when the file/directory is looked up with the same case as returned by
62 * ->ntfs_readdir() but that a lookup for any other case (or for the short file
63 * name) will not find anything in dcache and will enter ->ntfs_lookup()
64 * instead, where we search the directory for a fully matching file name
65 * (including case) and if that is not found, we search for a file name that
66 * matches with different case and if that has non-POSIX semantics we return
67 * that. We actually do only one search (case sensitive) and keep tabs on
68 * whether we have found a case insensitive match in the process.
69 *
70 * To simplify matters for us, we do not treat the short vs long filenames as
71 * two hard links but instead if the lookup matches a short filename, we
72 * return the dentry for the corresponding long filename instead.
73 *
74 * There are three cases we need to distinguish here:
75 *
76 * 1) @dent perfectly matches (i.e. including case) a directory entry with a
77 * file name in the WIN32 or POSIX namespaces. In this case
78 * ntfs_lookup_inode_by_name() will return with name set to NULL and we
79 * just d_splice_alias() @dent.
80 * 2) @dent matches (not including case) a directory entry with a file name in
81 * the WIN32 namespace. In this case ntfs_lookup_inode_by_name() will return
82 * with name set to point to a kmalloc()ed ntfs_name structure containing
83 * the properly cased little endian Unicode name. We convert the name to the
84 * current NLS code page, search if a dentry with this name already exists
85 * and if so return that instead of @dent. At this point things are
86 * complicated by the possibility of 'disconnected' dentries due to NFS
87 * which we deal with appropriately (see the code comments). The VFS will
88 * then destroy the old @dent and use the one we returned. If a dentry is
89 * not found, we allocate a new one, d_splice_alias() it, and return it as
90 * above.
91 * 3) @dent matches either perfectly or not (i.e. we don't care about case) a
92 * directory entry with a file name in the DOS namespace. In this case
93 * ntfs_lookup_inode_by_name() will return with name set to point to a
94 * kmalloc()ed ntfs_name structure containing the mft reference (cpu endian)
95 * of the inode. We use the mft reference to read the inode and to find the
96 * file name in the WIN32 namespace corresponding to the matched short file
97 * name. We then convert the name to the current NLS code page, and proceed
98 * searching for a dentry with this name, etc, as in case 2), above.
99 *
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800100 * Locking: Caller must hold i_mutex on the directory.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700101 */
102static struct dentry *ntfs_lookup(struct inode *dir_ino, struct dentry *dent,
103 struct nameidata *nd)
104{
105 ntfs_volume *vol = NTFS_SB(dir_ino->i_sb);
106 struct inode *dent_inode;
107 ntfschar *uname;
108 ntfs_name *name = NULL;
109 MFT_REF mref;
110 unsigned long dent_ino;
111 int uname_len;
112
113 ntfs_debug("Looking up %s in directory inode 0x%lx.",
114 dent->d_name.name, dir_ino->i_ino);
115 /* Convert the name of the dentry to Unicode. */
116 uname_len = ntfs_nlstoucs(vol, dent->d_name.name, dent->d_name.len,
117 &uname);
118 if (uname_len < 0) {
Anton Altaparmakov834ba602006-03-23 16:25:23 +0000119 if (uname_len != -ENAMETOOLONG)
120 ntfs_error(vol->sb, "Failed to convert name to "
121 "Unicode.");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700122 return ERR_PTR(uname_len);
123 }
124 mref = ntfs_lookup_inode_by_name(NTFS_I(dir_ino), uname, uname_len,
125 &name);
126 kmem_cache_free(ntfs_name_cache, uname);
127 if (!IS_ERR_MREF(mref)) {
128 dent_ino = MREF(mref);
129 ntfs_debug("Found inode 0x%lx. Calling ntfs_iget.", dent_ino);
130 dent_inode = ntfs_iget(vol->sb, dent_ino);
131 if (likely(!IS_ERR(dent_inode))) {
132 /* Consistency check. */
133 if (is_bad_inode(dent_inode) || MSEQNO(mref) ==
134 NTFS_I(dent_inode)->seq_no ||
135 dent_ino == FILE_MFT) {
136 /* Perfect WIN32/POSIX match. -- Case 1. */
137 if (!name) {
138 ntfs_debug("Done. (Case 1.)");
139 return d_splice_alias(dent_inode, dent);
140 }
141 /*
142 * We are too indented. Handle imperfect
143 * matches and short file names further below.
144 */
145 goto handle_name;
146 }
147 ntfs_error(vol->sb, "Found stale reference to inode "
148 "0x%lx (reference sequence number = "
149 "0x%x, inode sequence number = 0x%x), "
150 "returning -EIO. Run chkdsk.",
151 dent_ino, MSEQNO(mref),
152 NTFS_I(dent_inode)->seq_no);
153 iput(dent_inode);
154 dent_inode = ERR_PTR(-EIO);
155 } else
156 ntfs_error(vol->sb, "ntfs_iget(0x%lx) failed with "
157 "error code %li.", dent_ino,
158 PTR_ERR(dent_inode));
Jesper Juhl251c8422005-04-04 14:59:56 +0100159 kfree(name);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700160 /* Return the error code. */
161 return (struct dentry *)dent_inode;
162 }
Anton Altaparmakov834ba602006-03-23 16:25:23 +0000163 /* It is guaranteed that @name is no longer allocated at this point. */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700164 if (MREF_ERR(mref) == -ENOENT) {
165 ntfs_debug("Entry was not found, adding negative dentry.");
166 /* The dcache will handle negative entries. */
167 d_add(dent, NULL);
168 ntfs_debug("Done.");
169 return NULL;
170 }
171 ntfs_error(vol->sb, "ntfs_lookup_ino_by_name() failed with error "
172 "code %i.", -MREF_ERR(mref));
173 return ERR_PTR(MREF_ERR(mref));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700174 // TODO: Consider moving this lot to a separate function! (AIA)
175handle_name:
176 {
177 struct dentry *real_dent, *new_dent;
178 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
258 /*
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800259 * Note: No need for dent->d_lock lock as i_mutex is held on the
Linus Torvalds1da177e2005-04-16 15:20:36 -0700260 * parent inode.
261 */
262
263 /* Does a dentry matching the nls_name exist already? */
264 real_dent = d_lookup(dent->d_parent, &nls_name);
265 /* If not, create it now. */
266 if (!real_dent) {
267 real_dent = d_alloc(dent->d_parent, &nls_name);
268 kfree(nls_name.name);
269 if (!real_dent) {
270 err = -ENOMEM;
271 goto err_out;
272 }
273 new_dent = d_splice_alias(dent_inode, real_dent);
274 if (new_dent)
275 dput(real_dent);
276 else
277 new_dent = real_dent;
278 ntfs_debug("Done. (Created new dentry.)");
279 return new_dent;
280 }
281 kfree(nls_name.name);
282 /* Matching dentry exists, check if it is negative. */
283 if (real_dent->d_inode) {
284 if (unlikely(real_dent->d_inode != dent_inode)) {
285 /* This can happen because bad inodes are unhashed. */
286 BUG_ON(!is_bad_inode(dent_inode));
287 BUG_ON(!is_bad_inode(real_dent->d_inode));
288 }
289 /*
290 * Already have the inode and the dentry attached, decrement
291 * the reference count to balance the ntfs_iget() we did
292 * earlier on. We found the dentry using d_lookup() so it
293 * cannot be disconnected and thus we do not need to worry
294 * about any NFS/disconnectedness issues here.
295 */
296 iput(dent_inode);
297 ntfs_debug("Done. (Already had inode and dentry.)");
298 return real_dent;
299 }
300 /*
301 * Negative dentry: instantiate it unless the inode is a directory and
302 * has a 'disconnected' dentry (i.e. IS_ROOT and DCACHE_DISCONNECTED),
303 * in which case d_move() that in place of the found dentry.
304 */
305 if (!S_ISDIR(dent_inode->i_mode)) {
306 /* Not a directory; everything is easy. */
307 d_instantiate(real_dent, dent_inode);
308 ntfs_debug("Done. (Already had negative file dentry.)");
309 return real_dent;
310 }
311 spin_lock(&dcache_lock);
312 if (list_empty(&dent_inode->i_dentry)) {
313 /*
314 * Directory without a 'disconnected' dentry; we need to do
315 * d_instantiate() by hand because it takes dcache_lock which
316 * we already hold.
317 */
318 list_add(&real_dent->d_alias, &dent_inode->i_dentry);
319 real_dent->d_inode = dent_inode;
320 spin_unlock(&dcache_lock);
321 security_d_instantiate(real_dent, dent_inode);
322 ntfs_debug("Done. (Already had negative directory dentry.)");
323 return real_dent;
324 }
325 /*
326 * Directory with a 'disconnected' dentry; get a reference to the
327 * 'disconnected' dentry.
328 */
329 new_dent = list_entry(dent_inode->i_dentry.next, struct dentry,
330 d_alias);
331 dget_locked(new_dent);
332 spin_unlock(&dcache_lock);
333 /* Do security vodoo. */
334 security_d_instantiate(real_dent, dent_inode);
335 /* Move new_dent in place of real_dent. */
336 d_move(new_dent, real_dent);
337 /* Balance the ntfs_iget() we did above. */
338 iput(dent_inode);
339 /* Throw away real_dent. */
340 dput(real_dent);
341 /* Use new_dent as the actual dentry. */
342 ntfs_debug("Done. (Already had negative, disconnected directory "
343 "dentry.)");
344 return new_dent;
345
346eio_err_out:
347 ntfs_error(vol->sb, "Illegal file name attribute. Run chkdsk.");
348 err = -EIO;
349err_out:
350 if (ctx)
351 ntfs_attr_put_search_ctx(ctx);
352 if (m)
353 unmap_mft_record(ni);
354 iput(dent_inode);
355 ntfs_error(vol->sb, "Failed, returning error code %i.", err);
356 return ERR_PTR(err);
357 }
358}
359
360/**
361 * Inode operations for directories.
362 */
Arjan van de Ven92e1d5b2007-02-12 00:55:39 -0800363const struct inode_operations ntfs_dir_inode_ops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700364 .lookup = ntfs_lookup, /* VFS: Lookup directory. */
365};
366
367/**
368 * ntfs_get_parent - find the dentry of the parent of a given directory dentry
369 * @child_dent: dentry of the directory whose parent directory to find
370 *
371 * Find the dentry for the parent directory of the directory specified by the
372 * dentry @child_dent. This function is called from
373 * fs/exportfs/expfs.c::find_exported_dentry() which in turn is called from the
374 * default ->decode_fh() which is export_decode_fh() in the same file.
375 *
376 * The code is based on the ext3 ->get_parent() implementation found in
377 * fs/ext3/namei.c::ext3_get_parent().
378 *
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800379 * Note: ntfs_get_parent() is called with @child_dent->d_inode->i_mutex down.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700380 *
381 * Return the dentry of the parent directory on success or the error code on
382 * error (IS_ERR() is true).
383 */
Anton Altaparmakov41382682005-03-03 13:44:15 +0000384static struct dentry *ntfs_get_parent(struct dentry *child_dent)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700385{
386 struct inode *vi = child_dent->d_inode;
387 ntfs_inode *ni = NTFS_I(vi);
388 MFT_RECORD *mrec;
389 ntfs_attr_search_ctx *ctx;
390 ATTR_RECORD *attr;
391 FILE_NAME_ATTR *fn;
392 struct inode *parent_vi;
393 struct dentry *parent_dent;
394 unsigned long parent_ino;
395 int err;
396
397 ntfs_debug("Entering for inode 0x%lx.", vi->i_ino);
398 /* Get the mft record of the inode belonging to the child dentry. */
399 mrec = map_mft_record(ni);
400 if (IS_ERR(mrec))
401 return (struct dentry *)mrec;
402 /* Find the first file name attribute in the mft record. */
403 ctx = ntfs_attr_get_search_ctx(ni, mrec);
404 if (unlikely(!ctx)) {
405 unmap_mft_record(ni);
406 return ERR_PTR(-ENOMEM);
407 }
408try_next:
409 err = ntfs_attr_lookup(AT_FILE_NAME, NULL, 0, CASE_SENSITIVE, 0, NULL,
410 0, ctx);
411 if (unlikely(err)) {
412 ntfs_attr_put_search_ctx(ctx);
413 unmap_mft_record(ni);
414 if (err == -ENOENT)
415 ntfs_error(vi->i_sb, "Inode 0x%lx does not have a "
416 "file name attribute. Run chkdsk.",
417 vi->i_ino);
418 return ERR_PTR(err);
419 }
420 attr = ctx->attr;
421 if (unlikely(attr->non_resident))
422 goto try_next;
423 fn = (FILE_NAME_ATTR *)((u8 *)attr +
424 le16_to_cpu(attr->data.resident.value_offset));
425 if (unlikely((u8 *)fn + le32_to_cpu(attr->data.resident.value_length) >
426 (u8*)attr + le32_to_cpu(attr->length)))
427 goto try_next;
428 /* Get the inode number of the parent directory. */
429 parent_ino = MREF_LE(fn->parent_directory);
430 /* Release the search context and the mft record of the child. */
431 ntfs_attr_put_search_ctx(ctx);
432 unmap_mft_record(ni);
433 /* Get the inode of the parent directory. */
434 parent_vi = ntfs_iget(vi->i_sb, parent_ino);
435 if (IS_ERR(parent_vi) || unlikely(is_bad_inode(parent_vi))) {
436 if (!IS_ERR(parent_vi))
437 iput(parent_vi);
438 ntfs_error(vi->i_sb, "Failed to get parent directory inode "
439 "0x%lx of child inode 0x%lx.", parent_ino,
440 vi->i_ino);
441 return ERR_PTR(-EACCES);
442 }
443 /* Finally get a dentry for the parent directory and return it. */
444 parent_dent = d_alloc_anon(parent_vi);
445 if (unlikely(!parent_dent)) {
446 iput(parent_vi);
447 return ERR_PTR(-ENOMEM);
448 }
449 ntfs_debug("Done for inode 0x%lx.", vi->i_ino);
450 return parent_dent;
451}
452
Christoph Hellwiga3513202007-10-21 16:42:10 -0700453static struct inode *ntfs_nfs_get_inode(struct super_block *sb,
454 u64 ino, u32 generation)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700455{
Christoph Hellwiga3513202007-10-21 16:42:10 -0700456 struct inode *inode;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700457
Christoph Hellwiga3513202007-10-21 16:42:10 -0700458 inode = ntfs_iget(sb, ino);
459 if (!IS_ERR(inode)) {
460 if (is_bad_inode(inode) || inode->i_generation != generation) {
461 iput(inode);
462 inode = ERR_PTR(-ESTALE);
463 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700464 }
Christoph Hellwiga3513202007-10-21 16:42:10 -0700465
466 return inode;
467}
468
469static struct dentry *ntfs_fh_to_dentry(struct super_block *sb, struct fid *fid,
470 int fh_len, int fh_type)
471{
472 return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
473 ntfs_nfs_get_inode);
474}
475
476static struct dentry *ntfs_fh_to_parent(struct super_block *sb, struct fid *fid,
477 int fh_len, int fh_type)
478{
479 return generic_fh_to_parent(sb, fid, fh_len, fh_type,
480 ntfs_nfs_get_inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700481}
Anton Altaparmakov41382682005-03-03 13:44:15 +0000482
483/**
484 * Export operations allowing NFS exporting of mounted NTFS partitions.
485 *
Christoph Hellwiga3513202007-10-21 16:42:10 -0700486 * We use the default ->encode_fh() for now. Note that they
Anton Altaparmakov41382682005-03-03 13:44:15 +0000487 * use 32 bits to store the inode number which is an unsigned long so on 64-bit
488 * architectures is usually 64 bits so it would all fail horribly on huge
489 * volumes. I guess we need to define our own encode and decode fh functions
490 * that store 64-bit inode numbers at some point but for now we will ignore the
491 * problem...
492 *
493 * We also use the default ->get_name() helper (used by ->decode_fh() via
494 * fs/exportfs/expfs.c::find_exported_dentry()) as that is completely fs
495 * independent.
496 *
497 * The default ->get_parent() just returns -EACCES so we have to provide our
498 * own and the default ->get_dentry() is incompatible with NTFS due to not
499 * allowing the inode number 0 which is used in NTFS for the system file $MFT
500 * and due to using iget() whereas NTFS needs ntfs_iget().
501 */
Christoph Hellwig39655162007-10-21 16:42:17 -0700502const struct export_operations ntfs_export_ops = {
Anton Altaparmakov41382682005-03-03 13:44:15 +0000503 .get_parent = ntfs_get_parent, /* Find the parent of a given
504 directory. */
Christoph Hellwiga3513202007-10-21 16:42:10 -0700505 .fh_to_dentry = ntfs_fh_to_dentry,
506 .fh_to_parent = ntfs_fh_to_parent,
Anton Altaparmakov41382682005-03-03 13:44:15 +0000507};