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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> | |
a5694255 | 24 | #include <linux/exportfs.h> |
1da177e4 | 25 | #include <linux/security.h> |
5a0e3ad6 | 26 | #include <linux/slab.h> |
1da177e4 LT |
27 | |
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 | * | |
1b1dcc1b | 101 | * Locking: Caller must hold i_mutex on the directory. |
1da177e4 LT |
102 | */ |
103 | static struct dentry *ntfs_lookup(struct inode *dir_ino, struct dentry *dent, | |
00cd8dd3 | 104 | unsigned int flags) |
1da177e4 LT |
105 | { |
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) { | |
834ba600 AA |
120 | if (uname_len != -ENAMETOOLONG) |
121 | ntfs_error(vol->sb, "Failed to convert name to " | |
122 | "Unicode."); | |
1da177e4 LT |
123 | 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)); | |
251c8427 | 160 | kfree(name); |
1da177e4 LT |
161 | /* Return the error code. */ |
162 | return (struct dentry *)dent_inode; | |
163 | } | |
834ba600 | 164 | /* It is guaranteed that @name is no longer allocated at this point. */ |
1da177e4 LT |
165 | 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)); | |
1da177e4 LT |
175 | // TODO: Consider moving this lot to a separate function! (AIA) |
176 | handle_name: | |
177 | { | |
1da177e4 LT |
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 | ||
26904217 | 258 | dent = d_add_ci(dent, dent_inode, &nls_name); |
1da177e4 | 259 | kfree(nls_name.name); |
26904217 | 260 | return dent; |
1da177e4 LT |
261 | |
262 | eio_err_out: | |
263 | ntfs_error(vol->sb, "Illegal file name attribute. Run chkdsk."); | |
264 | err = -EIO; | |
265 | err_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 | */ | |
92e1d5be | 279 | const struct inode_operations ntfs_dir_inode_ops = { |
1da177e4 LT |
280 | .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 | * | |
1b1dcc1b | 295 | * Note: ntfs_get_parent() is called with @child_dent->d_inode->i_mutex down. |
1da177e4 LT |
296 | * |
297 | * Return the dentry of the parent directory on success or the error code on | |
298 | * error (IS_ERR() is true). | |
299 | */ | |
41382686 | 300 | static struct dentry *ntfs_get_parent(struct dentry *child_dent) |
1da177e4 LT |
301 | { |
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; | |
1da177e4 LT |
308 | 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 | } | |
322 | try_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); | |
44003728 CH |
347 | |
348 | return d_obtain_alias(ntfs_iget(vi->i_sb, parent_ino)); | |
1da177e4 LT |
349 | } |
350 | ||
a3513206 CH |
351 | static struct inode *ntfs_nfs_get_inode(struct super_block *sb, |
352 | u64 ino, u32 generation) | |
1da177e4 | 353 | { |
a3513206 | 354 | struct inode *inode; |
1da177e4 | 355 | |
a3513206 CH |
356 | 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 | } | |
1da177e4 | 362 | } |
a3513206 CH |
363 | |
364 | return inode; | |
365 | } | |
366 | ||
367 | static 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 | ||
374 | static 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); | |
1da177e4 | 379 | } |
41382686 AA |
380 | |
381 | /** | |
382 | * Export operations allowing NFS exporting of mounted NTFS partitions. | |
383 | * | |
a3513206 | 384 | * We use the default ->encode_fh() for now. Note that they |
41382686 AA |
385 | * 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 | */ | |
39655164 | 400 | const struct export_operations ntfs_export_ops = { |
41382686 AA |
401 | .get_parent = ntfs_get_parent, /* Find the parent of a given |
402 | directory. */ | |
a3513206 CH |
403 | .fh_to_dentry = ntfs_fh_to_dentry, |
404 | .fh_to_parent = ntfs_fh_to_parent, | |
41382686 | 405 | }; |