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1da177e4 LT |
1 | /* |
2 | * namei.c - NTFS kernel directory inode operations. Part of the Linux-NTFS | |
3 | * project. | |
4 | * | |
67b1dfe7 | 5 | * Copyright (c) 2001-2006 Anton Altaparmakov |
1da177e4 LT |
6 | * |
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> | |
24 | #include <linux/security.h> | |
25 | ||
26 | #include "attrib.h" | |
27 | #include "debug.h" | |
28 | #include "dir.h" | |
29 | #include "mft.h" | |
30 | #include "ntfs.h" | |
31 | ||
32 | /** | |
33 | * ntfs_lookup - find the inode represented by a dentry in a directory inode | |
34 | * @dir_ino: directory inode in which to look for the inode | |
35 | * @dent: dentry representing the inode to look for | |
36 | * @nd: lookup nameidata | |
37 | * | |
38 | * In short, ntfs_lookup() looks for the inode represented by the dentry @dent | |
39 | * in the directory inode @dir_ino and if found attaches the inode to the | |
40 | * dentry @dent. | |
41 | * | |
42 | * In more detail, the dentry @dent specifies which inode to look for by | |
43 | * supplying the name of the inode in @dent->d_name.name. ntfs_lookup() | |
44 | * converts the name to Unicode and walks the contents of the directory inode | |
45 | * @dir_ino looking for the converted Unicode name. If the name is found in the | |
46 | * directory, the corresponding inode is loaded by calling ntfs_iget() on its | |
47 | * inode number and the inode is associated with the dentry @dent via a call to | |
48 | * d_splice_alias(). | |
49 | * | |
50 | * If the name is not found in the directory, a NULL inode is inserted into the | |
51 | * dentry @dent via a call to d_add(). The dentry is then termed a negative | |
52 | * dentry. | |
53 | * | |
54 | * Only if an actual error occurs, do we return an error via ERR_PTR(). | |
55 | * | |
56 | * In order to handle the case insensitivity issues of NTFS with regards to the | |
57 | * dcache and the dcache requiring only one dentry per directory, we deal with | |
58 | * dentry aliases that only differ in case in ->ntfs_lookup() while maintaining | |
59 | * a case sensitive dcache. This means that we get the full benefit of dcache | |
60 | * speed when the file/directory is looked up with the same case as returned by | |
61 | * ->ntfs_readdir() but that a lookup for any other case (or for the short file | |
62 | * name) will not find anything in dcache and will enter ->ntfs_lookup() | |
63 | * instead, where we search the directory for a fully matching file name | |
64 | * (including case) and if that is not found, we search for a file name that | |
65 | * matches with different case and if that has non-POSIX semantics we return | |
66 | * that. We actually do only one search (case sensitive) and keep tabs on | |
67 | * whether we have found a case insensitive match in the process. | |
68 | * | |
69 | * To simplify matters for us, we do not treat the short vs long filenames as | |
70 | * two hard links but instead if the lookup matches a short filename, we | |
71 | * return the dentry for the corresponding long filename instead. | |
72 | * | |
73 | * There are three cases we need to distinguish here: | |
74 | * | |
75 | * 1) @dent perfectly matches (i.e. including case) a directory entry with a | |
76 | * file name in the WIN32 or POSIX namespaces. In this case | |
77 | * ntfs_lookup_inode_by_name() will return with name set to NULL and we | |
78 | * just d_splice_alias() @dent. | |
79 | * 2) @dent matches (not including case) a directory entry with a file name in | |
80 | * the WIN32 namespace. In this case ntfs_lookup_inode_by_name() will return | |
81 | * with name set to point to a kmalloc()ed ntfs_name structure containing | |
82 | * the properly cased little endian Unicode name. We convert the name to the | |
83 | * current NLS code page, search if a dentry with this name already exists | |
84 | * and if so return that instead of @dent. At this point things are | |
85 | * complicated by the possibility of 'disconnected' dentries due to NFS | |
86 | * which we deal with appropriately (see the code comments). The VFS will | |
87 | * then destroy the old @dent and use the one we returned. If a dentry is | |
88 | * not found, we allocate a new one, d_splice_alias() it, and return it as | |
89 | * above. | |
90 | * 3) @dent matches either perfectly or not (i.e. we don't care about case) a | |
91 | * directory entry with a file name in the DOS namespace. In this case | |
92 | * ntfs_lookup_inode_by_name() will return with name set to point to a | |
93 | * kmalloc()ed ntfs_name structure containing the mft reference (cpu endian) | |
94 | * of the inode. We use the mft reference to read the inode and to find the | |
95 | * file name in the WIN32 namespace corresponding to the matched short file | |
96 | * name. We then convert the name to the current NLS code page, and proceed | |
97 | * searching for a dentry with this name, etc, as in case 2), above. | |
98 | * | |
1b1dcc1b | 99 | * Locking: Caller must hold i_mutex on the directory. |
1da177e4 LT |
100 | */ |
101 | static struct dentry *ntfs_lookup(struct inode *dir_ino, struct dentry *dent, | |
102 | struct nameidata *nd) | |
103 | { | |
104 | ntfs_volume *vol = NTFS_SB(dir_ino->i_sb); | |
105 | struct inode *dent_inode; | |
106 | ntfschar *uname; | |
107 | ntfs_name *name = NULL; | |
108 | MFT_REF mref; | |
109 | unsigned long dent_ino; | |
110 | int uname_len; | |
111 | ||
112 | ntfs_debug("Looking up %s in directory inode 0x%lx.", | |
113 | dent->d_name.name, dir_ino->i_ino); | |
114 | /* Convert the name of the dentry to Unicode. */ | |
115 | uname_len = ntfs_nlstoucs(vol, dent->d_name.name, dent->d_name.len, | |
116 | &uname); | |
117 | if (uname_len < 0) { | |
118 | ntfs_error(vol->sb, "Failed to convert name to Unicode."); | |
119 | return ERR_PTR(uname_len); | |
120 | } | |
121 | mref = ntfs_lookup_inode_by_name(NTFS_I(dir_ino), uname, uname_len, | |
122 | &name); | |
123 | kmem_cache_free(ntfs_name_cache, uname); | |
124 | if (!IS_ERR_MREF(mref)) { | |
125 | dent_ino = MREF(mref); | |
126 | ntfs_debug("Found inode 0x%lx. Calling ntfs_iget.", dent_ino); | |
127 | dent_inode = ntfs_iget(vol->sb, dent_ino); | |
128 | if (likely(!IS_ERR(dent_inode))) { | |
129 | /* Consistency check. */ | |
130 | if (is_bad_inode(dent_inode) || MSEQNO(mref) == | |
131 | NTFS_I(dent_inode)->seq_no || | |
132 | dent_ino == FILE_MFT) { | |
133 | /* Perfect WIN32/POSIX match. -- Case 1. */ | |
134 | if (!name) { | |
135 | ntfs_debug("Done. (Case 1.)"); | |
136 | return d_splice_alias(dent_inode, dent); | |
137 | } | |
138 | /* | |
139 | * We are too indented. Handle imperfect | |
140 | * matches and short file names further below. | |
141 | */ | |
142 | goto handle_name; | |
143 | } | |
144 | ntfs_error(vol->sb, "Found stale reference to inode " | |
145 | "0x%lx (reference sequence number = " | |
146 | "0x%x, inode sequence number = 0x%x), " | |
147 | "returning -EIO. Run chkdsk.", | |
148 | dent_ino, MSEQNO(mref), | |
149 | NTFS_I(dent_inode)->seq_no); | |
150 | iput(dent_inode); | |
151 | dent_inode = ERR_PTR(-EIO); | |
152 | } else | |
153 | ntfs_error(vol->sb, "ntfs_iget(0x%lx) failed with " | |
154 | "error code %li.", dent_ino, | |
155 | PTR_ERR(dent_inode)); | |
251c8427 | 156 | kfree(name); |
1da177e4 LT |
157 | /* Return the error code. */ |
158 | return (struct dentry *)dent_inode; | |
159 | } | |
160 | /* It is guaranteed that name is no longer allocated at this point. */ | |
161 | if (MREF_ERR(mref) == -ENOENT) { | |
162 | ntfs_debug("Entry was not found, adding negative dentry."); | |
163 | /* The dcache will handle negative entries. */ | |
164 | d_add(dent, NULL); | |
165 | ntfs_debug("Done."); | |
166 | return NULL; | |
167 | } | |
168 | ntfs_error(vol->sb, "ntfs_lookup_ino_by_name() failed with error " | |
169 | "code %i.", -MREF_ERR(mref)); | |
170 | return ERR_PTR(MREF_ERR(mref)); | |
171 | ||
172 | // TODO: Consider moving this lot to a separate function! (AIA) | |
173 | handle_name: | |
174 | { | |
175 | struct dentry *real_dent, *new_dent; | |
176 | MFT_RECORD *m; | |
177 | ntfs_attr_search_ctx *ctx; | |
178 | ntfs_inode *ni = NTFS_I(dent_inode); | |
179 | int err; | |
180 | struct qstr nls_name; | |
181 | ||
182 | nls_name.name = NULL; | |
183 | if (name->type != FILE_NAME_DOS) { /* Case 2. */ | |
184 | ntfs_debug("Case 2."); | |
185 | nls_name.len = (unsigned)ntfs_ucstonls(vol, | |
186 | (ntfschar*)&name->name, name->len, | |
187 | (unsigned char**)&nls_name.name, 0); | |
188 | kfree(name); | |
189 | } else /* if (name->type == FILE_NAME_DOS) */ { /* Case 3. */ | |
190 | FILE_NAME_ATTR *fn; | |
191 | ||
192 | ntfs_debug("Case 3."); | |
193 | kfree(name); | |
194 | ||
195 | /* Find the WIN32 name corresponding to the matched DOS name. */ | |
196 | ni = NTFS_I(dent_inode); | |
197 | m = map_mft_record(ni); | |
198 | if (IS_ERR(m)) { | |
199 | err = PTR_ERR(m); | |
200 | m = NULL; | |
201 | ctx = NULL; | |
202 | goto err_out; | |
203 | } | |
204 | ctx = ntfs_attr_get_search_ctx(ni, m); | |
205 | if (unlikely(!ctx)) { | |
206 | err = -ENOMEM; | |
207 | goto err_out; | |
208 | } | |
209 | do { | |
210 | ATTR_RECORD *a; | |
211 | u32 val_len; | |
212 | ||
213 | err = ntfs_attr_lookup(AT_FILE_NAME, NULL, 0, 0, 0, | |
214 | NULL, 0, ctx); | |
215 | if (unlikely(err)) { | |
216 | ntfs_error(vol->sb, "Inode corrupt: No WIN32 " | |
217 | "namespace counterpart to DOS " | |
218 | "file name. Run chkdsk."); | |
219 | if (err == -ENOENT) | |
220 | err = -EIO; | |
221 | goto err_out; | |
222 | } | |
223 | /* Consistency checks. */ | |
224 | a = ctx->attr; | |
225 | if (a->non_resident || a->flags) | |
226 | goto eio_err_out; | |
227 | val_len = le32_to_cpu(a->data.resident.value_length); | |
228 | if (le16_to_cpu(a->data.resident.value_offset) + | |
229 | val_len > le32_to_cpu(a->length)) | |
230 | goto eio_err_out; | |
231 | fn = (FILE_NAME_ATTR*)((u8*)ctx->attr + le16_to_cpu( | |
232 | ctx->attr->data.resident.value_offset)); | |
233 | if ((u32)(fn->file_name_length * sizeof(ntfschar) + | |
234 | sizeof(FILE_NAME_ATTR)) > val_len) | |
235 | goto eio_err_out; | |
236 | } while (fn->file_name_type != FILE_NAME_WIN32); | |
237 | ||
238 | /* Convert the found WIN32 name to current NLS code page. */ | |
239 | nls_name.len = (unsigned)ntfs_ucstonls(vol, | |
240 | (ntfschar*)&fn->file_name, fn->file_name_length, | |
241 | (unsigned char**)&nls_name.name, 0); | |
242 | ||
243 | ntfs_attr_put_search_ctx(ctx); | |
244 | unmap_mft_record(ni); | |
245 | } | |
246 | m = NULL; | |
247 | ctx = NULL; | |
248 | ||
249 | /* Check if a conversion error occurred. */ | |
250 | if ((signed)nls_name.len < 0) { | |
251 | err = (signed)nls_name.len; | |
252 | goto err_out; | |
253 | } | |
254 | nls_name.hash = full_name_hash(nls_name.name, nls_name.len); | |
255 | ||
256 | /* | |
1b1dcc1b | 257 | * Note: No need for dent->d_lock lock as i_mutex is held on the |
1da177e4 LT |
258 | * parent inode. |
259 | */ | |
260 | ||
261 | /* Does a dentry matching the nls_name exist already? */ | |
262 | real_dent = d_lookup(dent->d_parent, &nls_name); | |
263 | /* If not, create it now. */ | |
264 | if (!real_dent) { | |
265 | real_dent = d_alloc(dent->d_parent, &nls_name); | |
266 | kfree(nls_name.name); | |
267 | if (!real_dent) { | |
268 | err = -ENOMEM; | |
269 | goto err_out; | |
270 | } | |
271 | new_dent = d_splice_alias(dent_inode, real_dent); | |
272 | if (new_dent) | |
273 | dput(real_dent); | |
274 | else | |
275 | new_dent = real_dent; | |
276 | ntfs_debug("Done. (Created new dentry.)"); | |
277 | return new_dent; | |
278 | } | |
279 | kfree(nls_name.name); | |
280 | /* Matching dentry exists, check if it is negative. */ | |
281 | if (real_dent->d_inode) { | |
282 | if (unlikely(real_dent->d_inode != dent_inode)) { | |
283 | /* This can happen because bad inodes are unhashed. */ | |
284 | BUG_ON(!is_bad_inode(dent_inode)); | |
285 | BUG_ON(!is_bad_inode(real_dent->d_inode)); | |
286 | } | |
287 | /* | |
288 | * Already have the inode and the dentry attached, decrement | |
289 | * the reference count to balance the ntfs_iget() we did | |
290 | * earlier on. We found the dentry using d_lookup() so it | |
291 | * cannot be disconnected and thus we do not need to worry | |
292 | * about any NFS/disconnectedness issues here. | |
293 | */ | |
294 | iput(dent_inode); | |
295 | ntfs_debug("Done. (Already had inode and dentry.)"); | |
296 | return real_dent; | |
297 | } | |
298 | /* | |
299 | * Negative dentry: instantiate it unless the inode is a directory and | |
300 | * has a 'disconnected' dentry (i.e. IS_ROOT and DCACHE_DISCONNECTED), | |
301 | * in which case d_move() that in place of the found dentry. | |
302 | */ | |
303 | if (!S_ISDIR(dent_inode->i_mode)) { | |
304 | /* Not a directory; everything is easy. */ | |
305 | d_instantiate(real_dent, dent_inode); | |
306 | ntfs_debug("Done. (Already had negative file dentry.)"); | |
307 | return real_dent; | |
308 | } | |
309 | spin_lock(&dcache_lock); | |
310 | if (list_empty(&dent_inode->i_dentry)) { | |
311 | /* | |
312 | * Directory without a 'disconnected' dentry; we need to do | |
313 | * d_instantiate() by hand because it takes dcache_lock which | |
314 | * we already hold. | |
315 | */ | |
316 | list_add(&real_dent->d_alias, &dent_inode->i_dentry); | |
317 | real_dent->d_inode = dent_inode; | |
318 | spin_unlock(&dcache_lock); | |
319 | security_d_instantiate(real_dent, dent_inode); | |
320 | ntfs_debug("Done. (Already had negative directory dentry.)"); | |
321 | return real_dent; | |
322 | } | |
323 | /* | |
324 | * Directory with a 'disconnected' dentry; get a reference to the | |
325 | * 'disconnected' dentry. | |
326 | */ | |
327 | new_dent = list_entry(dent_inode->i_dentry.next, struct dentry, | |
328 | d_alias); | |
329 | dget_locked(new_dent); | |
330 | spin_unlock(&dcache_lock); | |
331 | /* Do security vodoo. */ | |
332 | security_d_instantiate(real_dent, dent_inode); | |
333 | /* Move new_dent in place of real_dent. */ | |
334 | d_move(new_dent, real_dent); | |
335 | /* Balance the ntfs_iget() we did above. */ | |
336 | iput(dent_inode); | |
337 | /* Throw away real_dent. */ | |
338 | dput(real_dent); | |
339 | /* Use new_dent as the actual dentry. */ | |
340 | ntfs_debug("Done. (Already had negative, disconnected directory " | |
341 | "dentry.)"); | |
342 | return new_dent; | |
343 | ||
344 | eio_err_out: | |
345 | ntfs_error(vol->sb, "Illegal file name attribute. Run chkdsk."); | |
346 | err = -EIO; | |
347 | err_out: | |
348 | if (ctx) | |
349 | ntfs_attr_put_search_ctx(ctx); | |
350 | if (m) | |
351 | unmap_mft_record(ni); | |
352 | iput(dent_inode); | |
353 | ntfs_error(vol->sb, "Failed, returning error code %i.", err); | |
354 | return ERR_PTR(err); | |
355 | } | |
356 | } | |
357 | ||
358 | /** | |
359 | * Inode operations for directories. | |
360 | */ | |
361 | struct inode_operations ntfs_dir_inode_ops = { | |
362 | .lookup = ntfs_lookup, /* VFS: Lookup directory. */ | |
363 | }; | |
364 | ||
365 | /** | |
366 | * ntfs_get_parent - find the dentry of the parent of a given directory dentry | |
367 | * @child_dent: dentry of the directory whose parent directory to find | |
368 | * | |
369 | * Find the dentry for the parent directory of the directory specified by the | |
370 | * dentry @child_dent. This function is called from | |
371 | * fs/exportfs/expfs.c::find_exported_dentry() which in turn is called from the | |
372 | * default ->decode_fh() which is export_decode_fh() in the same file. | |
373 | * | |
374 | * The code is based on the ext3 ->get_parent() implementation found in | |
375 | * fs/ext3/namei.c::ext3_get_parent(). | |
376 | * | |
1b1dcc1b | 377 | * Note: ntfs_get_parent() is called with @child_dent->d_inode->i_mutex down. |
1da177e4 LT |
378 | * |
379 | * Return the dentry of the parent directory on success or the error code on | |
380 | * error (IS_ERR() is true). | |
381 | */ | |
41382686 | 382 | static struct dentry *ntfs_get_parent(struct dentry *child_dent) |
1da177e4 LT |
383 | { |
384 | struct inode *vi = child_dent->d_inode; | |
385 | ntfs_inode *ni = NTFS_I(vi); | |
386 | MFT_RECORD *mrec; | |
387 | ntfs_attr_search_ctx *ctx; | |
388 | ATTR_RECORD *attr; | |
389 | FILE_NAME_ATTR *fn; | |
390 | struct inode *parent_vi; | |
391 | struct dentry *parent_dent; | |
392 | unsigned long parent_ino; | |
393 | int err; | |
394 | ||
395 | ntfs_debug("Entering for inode 0x%lx.", vi->i_ino); | |
396 | /* Get the mft record of the inode belonging to the child dentry. */ | |
397 | mrec = map_mft_record(ni); | |
398 | if (IS_ERR(mrec)) | |
399 | return (struct dentry *)mrec; | |
400 | /* Find the first file name attribute in the mft record. */ | |
401 | ctx = ntfs_attr_get_search_ctx(ni, mrec); | |
402 | if (unlikely(!ctx)) { | |
403 | unmap_mft_record(ni); | |
404 | return ERR_PTR(-ENOMEM); | |
405 | } | |
406 | try_next: | |
407 | err = ntfs_attr_lookup(AT_FILE_NAME, NULL, 0, CASE_SENSITIVE, 0, NULL, | |
408 | 0, ctx); | |
409 | if (unlikely(err)) { | |
410 | ntfs_attr_put_search_ctx(ctx); | |
411 | unmap_mft_record(ni); | |
412 | if (err == -ENOENT) | |
413 | ntfs_error(vi->i_sb, "Inode 0x%lx does not have a " | |
414 | "file name attribute. Run chkdsk.", | |
415 | vi->i_ino); | |
416 | return ERR_PTR(err); | |
417 | } | |
418 | attr = ctx->attr; | |
419 | if (unlikely(attr->non_resident)) | |
420 | goto try_next; | |
421 | fn = (FILE_NAME_ATTR *)((u8 *)attr + | |
422 | le16_to_cpu(attr->data.resident.value_offset)); | |
423 | if (unlikely((u8 *)fn + le32_to_cpu(attr->data.resident.value_length) > | |
424 | (u8*)attr + le32_to_cpu(attr->length))) | |
425 | goto try_next; | |
426 | /* Get the inode number of the parent directory. */ | |
427 | parent_ino = MREF_LE(fn->parent_directory); | |
428 | /* Release the search context and the mft record of the child. */ | |
429 | ntfs_attr_put_search_ctx(ctx); | |
430 | unmap_mft_record(ni); | |
431 | /* Get the inode of the parent directory. */ | |
432 | parent_vi = ntfs_iget(vi->i_sb, parent_ino); | |
433 | if (IS_ERR(parent_vi) || unlikely(is_bad_inode(parent_vi))) { | |
434 | if (!IS_ERR(parent_vi)) | |
435 | iput(parent_vi); | |
436 | ntfs_error(vi->i_sb, "Failed to get parent directory inode " | |
437 | "0x%lx of child inode 0x%lx.", parent_ino, | |
438 | vi->i_ino); | |
439 | return ERR_PTR(-EACCES); | |
440 | } | |
441 | /* Finally get a dentry for the parent directory and return it. */ | |
442 | parent_dent = d_alloc_anon(parent_vi); | |
443 | if (unlikely(!parent_dent)) { | |
444 | iput(parent_vi); | |
445 | return ERR_PTR(-ENOMEM); | |
446 | } | |
447 | ntfs_debug("Done for inode 0x%lx.", vi->i_ino); | |
448 | return parent_dent; | |
449 | } | |
450 | ||
451 | /** | |
452 | * ntfs_get_dentry - find a dentry for the inode from a file handle sub-fragment | |
453 | * @sb: super block identifying the mounted ntfs volume | |
454 | * @fh: the file handle sub-fragment | |
455 | * | |
456 | * Find a dentry for the inode given a file handle sub-fragment. This function | |
457 | * is called from fs/exportfs/expfs.c::find_exported_dentry() which in turn is | |
458 | * called from the default ->decode_fh() which is export_decode_fh() in the | |
459 | * same file. The code is closely based on the default ->get_dentry() helper | |
460 | * fs/exportfs/expfs.c::get_object(). | |
461 | * | |
462 | * The @fh contains two 32-bit unsigned values, the first one is the inode | |
463 | * number and the second one is the inode generation. | |
464 | * | |
465 | * Return the dentry on success or the error code on error (IS_ERR() is true). | |
466 | */ | |
41382686 | 467 | static struct dentry *ntfs_get_dentry(struct super_block *sb, void *fh) |
1da177e4 LT |
468 | { |
469 | struct inode *vi; | |
470 | struct dentry *dent; | |
471 | unsigned long ino = ((u32 *)fh)[0]; | |
472 | u32 gen = ((u32 *)fh)[1]; | |
473 | ||
474 | ntfs_debug("Entering for inode 0x%lx, generation 0x%x.", ino, gen); | |
475 | vi = ntfs_iget(sb, ino); | |
476 | if (IS_ERR(vi)) { | |
477 | ntfs_error(sb, "Failed to get inode 0x%lx.", ino); | |
478 | return (struct dentry *)vi; | |
479 | } | |
480 | if (unlikely(is_bad_inode(vi) || vi->i_generation != gen)) { | |
481 | /* We didn't find the right inode. */ | |
482 | ntfs_error(sb, "Inode 0x%lx, bad count: %d %d or version 0x%x " | |
483 | "0x%x.", vi->i_ino, vi->i_nlink, | |
484 | atomic_read(&vi->i_count), vi->i_generation, | |
485 | gen); | |
486 | iput(vi); | |
487 | return ERR_PTR(-ESTALE); | |
488 | } | |
489 | /* Now find a dentry. If possible, get a well-connected one. */ | |
490 | dent = d_alloc_anon(vi); | |
491 | if (unlikely(!dent)) { | |
492 | iput(vi); | |
493 | return ERR_PTR(-ENOMEM); | |
494 | } | |
495 | ntfs_debug("Done for inode 0x%lx, generation 0x%x.", ino, gen); | |
496 | return dent; | |
497 | } | |
41382686 AA |
498 | |
499 | /** | |
500 | * Export operations allowing NFS exporting of mounted NTFS partitions. | |
501 | * | |
502 | * We use the default ->decode_fh() and ->encode_fh() for now. Note that they | |
503 | * use 32 bits to store the inode number which is an unsigned long so on 64-bit | |
504 | * architectures is usually 64 bits so it would all fail horribly on huge | |
505 | * volumes. I guess we need to define our own encode and decode fh functions | |
506 | * that store 64-bit inode numbers at some point but for now we will ignore the | |
507 | * problem... | |
508 | * | |
509 | * We also use the default ->get_name() helper (used by ->decode_fh() via | |
510 | * fs/exportfs/expfs.c::find_exported_dentry()) as that is completely fs | |
511 | * independent. | |
512 | * | |
513 | * The default ->get_parent() just returns -EACCES so we have to provide our | |
514 | * own and the default ->get_dentry() is incompatible with NTFS due to not | |
515 | * allowing the inode number 0 which is used in NTFS for the system file $MFT | |
516 | * and due to using iget() whereas NTFS needs ntfs_iget(). | |
517 | */ | |
518 | struct export_operations ntfs_export_ops = { | |
519 | .get_parent = ntfs_get_parent, /* Find the parent of a given | |
520 | directory. */ | |
521 | .get_dentry = ntfs_get_dentry, /* Find a dentry for the inode | |
522 | given a file handle | |
523 | sub-fragment. */ | |
524 | }; |