Root/fs/ntfs/dir.c

1/**
2 * dir.c - NTFS kernel directory operations. Part of the Linux-NTFS project.
3 *
4 * Copyright (c) 2001-2007 Anton Altaparmakov
5 * Copyright (c) 2002 Richard Russon
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/buffer_head.h>
24#include <linux/slab.h>
25
26#include "dir.h"
27#include "aops.h"
28#include "attrib.h"
29#include "mft.h"
30#include "debug.h"
31#include "ntfs.h"
32
33/**
34 * The little endian Unicode string $I30 as a global constant.
35 */
36ntfschar I30[5] = { cpu_to_le16('$'), cpu_to_le16('I'),
37        cpu_to_le16('3'), cpu_to_le16('0'), 0 };
38
39/**
40 * ntfs_lookup_inode_by_name - find an inode in a directory given its name
41 * @dir_ni: ntfs inode of the directory in which to search for the name
42 * @uname: Unicode name for which to search in the directory
43 * @uname_len: length of the name @uname in Unicode characters
44 * @res: return the found file name if necessary (see below)
45 *
46 * Look for an inode with name @uname in the directory with inode @dir_ni.
47 * ntfs_lookup_inode_by_name() walks the contents of the directory looking for
48 * the Unicode name. If the name is found in the directory, the corresponding
49 * inode number (>= 0) is returned as a mft reference in cpu format, i.e. it
50 * is a 64-bit number containing the sequence number.
51 *
52 * On error, a negative value is returned corresponding to the error code. In
53 * particular if the inode is not found -ENOENT is returned. Note that you
54 * can't just check the return value for being negative, you have to check the
55 * inode number for being negative which you can extract using MREC(return
56 * value).
57 *
58 * Note, @uname_len does not include the (optional) terminating NULL character.
59 *
60 * Note, we look for a case sensitive match first but we also look for a case
61 * insensitive match at the same time. If we find a case insensitive match, we
62 * save that for the case that we don't find an exact match, where we return
63 * the case insensitive match and setup @res (which we allocate!) with the mft
64 * reference, the file name type, length and with a copy of the little endian
65 * Unicode file name itself. If we match a file name which is in the DOS name
66 * space, we only return the mft reference and file name type in @res.
67 * ntfs_lookup() then uses this to find the long file name in the inode itself.
68 * This is to avoid polluting the dcache with short file names. We want them to
69 * work but we don't care for how quickly one can access them. This also fixes
70 * the dcache aliasing issues.
71 *
72 * Locking: - Caller must hold i_mutex on the directory.
73 * - Each page cache page in the index allocation mapping must be
74 * locked whilst being accessed otherwise we may find a corrupt
75 * page due to it being under ->writepage at the moment which
76 * applies the mst protection fixups before writing out and then
77 * removes them again after the write is complete after which it
78 * unlocks the page.
79 */
80MFT_REF ntfs_lookup_inode_by_name(ntfs_inode *dir_ni, const ntfschar *uname,
81        const int uname_len, ntfs_name **res)
82{
83    ntfs_volume *vol = dir_ni->vol;
84    struct super_block *sb = vol->sb;
85    MFT_RECORD *m;
86    INDEX_ROOT *ir;
87    INDEX_ENTRY *ie;
88    INDEX_ALLOCATION *ia;
89    u8 *index_end;
90    u64 mref;
91    ntfs_attr_search_ctx *ctx;
92    int err, rc;
93    VCN vcn, old_vcn;
94    struct address_space *ia_mapping;
95    struct page *page;
96    u8 *kaddr;
97    ntfs_name *name = NULL;
98
99    BUG_ON(!S_ISDIR(VFS_I(dir_ni)->i_mode));
100    BUG_ON(NInoAttr(dir_ni));
101    /* Get hold of the mft record for the directory. */
102    m = map_mft_record(dir_ni);
103    if (IS_ERR(m)) {
104        ntfs_error(sb, "map_mft_record() failed with error code %ld.",
105                -PTR_ERR(m));
106        return ERR_MREF(PTR_ERR(m));
107    }
108    ctx = ntfs_attr_get_search_ctx(dir_ni, m);
109    if (unlikely(!ctx)) {
110        err = -ENOMEM;
111        goto err_out;
112    }
113    /* Find the index root attribute in the mft record. */
114    err = ntfs_attr_lookup(AT_INDEX_ROOT, I30, 4, CASE_SENSITIVE, 0, NULL,
115            0, ctx);
116    if (unlikely(err)) {
117        if (err == -ENOENT) {
118            ntfs_error(sb, "Index root attribute missing in "
119                    "directory inode 0x%lx.",
120                    dir_ni->mft_no);
121            err = -EIO;
122        }
123        goto err_out;
124    }
125    /* Get to the index root value (it's been verified in read_inode). */
126    ir = (INDEX_ROOT*)((u8*)ctx->attr +
127            le16_to_cpu(ctx->attr->data.resident.value_offset));
128    index_end = (u8*)&ir->index + le32_to_cpu(ir->index.index_length);
129    /* The first index entry. */
130    ie = (INDEX_ENTRY*)((u8*)&ir->index +
131            le32_to_cpu(ir->index.entries_offset));
132    /*
133     * Loop until we exceed valid memory (corruption case) or until we
134     * reach the last entry.
135     */
136    for (;; ie = (INDEX_ENTRY*)((u8*)ie + le16_to_cpu(ie->length))) {
137        /* Bounds checks. */
138        if ((u8*)ie < (u8*)ctx->mrec || (u8*)ie +
139                sizeof(INDEX_ENTRY_HEADER) > index_end ||
140                (u8*)ie + le16_to_cpu(ie->key_length) >
141                index_end)
142            goto dir_err_out;
143        /*
144         * The last entry cannot contain a name. It can however contain
145         * a pointer to a child node in the B+tree so we just break out.
146         */
147        if (ie->flags & INDEX_ENTRY_END)
148            break;
149        /*
150         * We perform a case sensitive comparison and if that matches
151         * we are done and return the mft reference of the inode (i.e.
152         * the inode number together with the sequence number for
153         * consistency checking). We convert it to cpu format before
154         * returning.
155         */
156        if (ntfs_are_names_equal(uname, uname_len,
157                (ntfschar*)&ie->key.file_name.file_name,
158                ie->key.file_name.file_name_length,
159                CASE_SENSITIVE, vol->upcase, vol->upcase_len)) {
160found_it:
161            /*
162             * We have a perfect match, so we don't need to care
163             * about having matched imperfectly before, so we can
164             * free name and set *res to NULL.
165             * However, if the perfect match is a short file name,
166             * we need to signal this through *res, so that
167             * ntfs_lookup() can fix dcache aliasing issues.
168             * As an optimization we just reuse an existing
169             * allocation of *res.
170             */
171            if (ie->key.file_name.file_name_type == FILE_NAME_DOS) {
172                if (!name) {
173                    name = kmalloc(sizeof(ntfs_name),
174                            GFP_NOFS);
175                    if (!name) {
176                        err = -ENOMEM;
177                        goto err_out;
178                    }
179                }
180                name->mref = le64_to_cpu(
181                        ie->data.dir.indexed_file);
182                name->type = FILE_NAME_DOS;
183                name->len = 0;
184                *res = name;
185            } else {
186                kfree(name);
187                *res = NULL;
188            }
189            mref = le64_to_cpu(ie->data.dir.indexed_file);
190            ntfs_attr_put_search_ctx(ctx);
191            unmap_mft_record(dir_ni);
192            return mref;
193        }
194        /*
195         * For a case insensitive mount, we also perform a case
196         * insensitive comparison (provided the file name is not in the
197         * POSIX namespace). If the comparison matches, and the name is
198         * in the WIN32 namespace, we cache the filename in *res so
199         * that the caller, ntfs_lookup(), can work on it. If the
200         * comparison matches, and the name is in the DOS namespace, we
201         * only cache the mft reference and the file name type (we set
202         * the name length to zero for simplicity).
203         */
204        if (!NVolCaseSensitive(vol) &&
205                ie->key.file_name.file_name_type &&
206                ntfs_are_names_equal(uname, uname_len,
207                (ntfschar*)&ie->key.file_name.file_name,
208                ie->key.file_name.file_name_length,
209                IGNORE_CASE, vol->upcase, vol->upcase_len)) {
210            int name_size = sizeof(ntfs_name);
211            u8 type = ie->key.file_name.file_name_type;
212            u8 len = ie->key.file_name.file_name_length;
213
214            /* Only one case insensitive matching name allowed. */
215            if (name) {
216                ntfs_error(sb, "Found already allocated name "
217                        "in phase 1. Please run chkdsk "
218                        "and if that doesn't find any "
219                        "errors please report you saw "
220                        "this message to "
221                        "linux-ntfs-dev@lists."
222                        "sourceforge.net.");
223                goto dir_err_out;
224            }
225
226            if (type != FILE_NAME_DOS)
227                name_size += len * sizeof(ntfschar);
228            name = kmalloc(name_size, GFP_NOFS);
229            if (!name) {
230                err = -ENOMEM;
231                goto err_out;
232            }
233            name->mref = le64_to_cpu(ie->data.dir.indexed_file);
234            name->type = type;
235            if (type != FILE_NAME_DOS) {
236                name->len = len;
237                memcpy(name->name, ie->key.file_name.file_name,
238                        len * sizeof(ntfschar));
239            } else
240                name->len = 0;
241            *res = name;
242        }
243        /*
244         * Not a perfect match, need to do full blown collation so we
245         * know which way in the B+tree we have to go.
246         */
247        rc = ntfs_collate_names(uname, uname_len,
248                (ntfschar*)&ie->key.file_name.file_name,
249                ie->key.file_name.file_name_length, 1,
250                IGNORE_CASE, vol->upcase, vol->upcase_len);
251        /*
252         * If uname collates before the name of the current entry, there
253         * is definitely no such name in this index but we might need to
254         * descend into the B+tree so we just break out of the loop.
255         */
256        if (rc == -1)
257            break;
258        /* The names are not equal, continue the search. */
259        if (rc)
260            continue;
261        /*
262         * Names match with case insensitive comparison, now try the
263         * case sensitive comparison, which is required for proper
264         * collation.
265         */
266        rc = ntfs_collate_names(uname, uname_len,
267                (ntfschar*)&ie->key.file_name.file_name,
268                ie->key.file_name.file_name_length, 1,
269                CASE_SENSITIVE, vol->upcase, vol->upcase_len);
270        if (rc == -1)
271            break;
272        if (rc)
273            continue;
274        /*
275         * Perfect match, this will never happen as the
276         * ntfs_are_names_equal() call will have gotten a match but we
277         * still treat it correctly.
278         */
279        goto found_it;
280    }
281    /*
282     * We have finished with this index without success. Check for the
283     * presence of a child node and if not present return -ENOENT, unless
284     * we have got a matching name cached in name in which case return the
285     * mft reference associated with it.
286     */
287    if (!(ie->flags & INDEX_ENTRY_NODE)) {
288        if (name) {
289            ntfs_attr_put_search_ctx(ctx);
290            unmap_mft_record(dir_ni);
291            return name->mref;
292        }
293        ntfs_debug("Entry not found.");
294        err = -ENOENT;
295        goto err_out;
296    } /* Child node present, descend into it. */
297    /* Consistency check: Verify that an index allocation exists. */
298    if (!NInoIndexAllocPresent(dir_ni)) {
299        ntfs_error(sb, "No index allocation attribute but index entry "
300                "requires one. Directory inode 0x%lx is "
301                "corrupt or driver bug.", dir_ni->mft_no);
302        goto err_out;
303    }
304    /* Get the starting vcn of the index_block holding the child node. */
305    vcn = sle64_to_cpup((sle64*)((u8*)ie + le16_to_cpu(ie->length) - 8));
306    ia_mapping = VFS_I(dir_ni)->i_mapping;
307    /*
308     * We are done with the index root and the mft record. Release them,
309     * otherwise we deadlock with ntfs_map_page().
310     */
311    ntfs_attr_put_search_ctx(ctx);
312    unmap_mft_record(dir_ni);
313    m = NULL;
314    ctx = NULL;
315descend_into_child_node:
316    /*
317     * Convert vcn to index into the index allocation attribute in units
318     * of PAGE_CACHE_SIZE and map the page cache page, reading it from
319     * disk if necessary.
320     */
321    page = ntfs_map_page(ia_mapping, vcn <<
322            dir_ni->itype.index.vcn_size_bits >> PAGE_CACHE_SHIFT);
323    if (IS_ERR(page)) {
324        ntfs_error(sb, "Failed to map directory index page, error %ld.",
325                -PTR_ERR(page));
326        err = PTR_ERR(page);
327        goto err_out;
328    }
329    lock_page(page);
330    kaddr = (u8*)page_address(page);
331fast_descend_into_child_node:
332    /* Get to the index allocation block. */
333    ia = (INDEX_ALLOCATION*)(kaddr + ((vcn <<
334            dir_ni->itype.index.vcn_size_bits) & ~PAGE_CACHE_MASK));
335    /* Bounds checks. */
336    if ((u8*)ia < kaddr || (u8*)ia > kaddr + PAGE_CACHE_SIZE) {
337        ntfs_error(sb, "Out of bounds check failed. Corrupt directory "
338                "inode 0x%lx or driver bug.", dir_ni->mft_no);
339        goto unm_err_out;
340    }
341    /* Catch multi sector transfer fixup errors. */
342    if (unlikely(!ntfs_is_indx_record(ia->magic))) {
343        ntfs_error(sb, "Directory index record with vcn 0x%llx is "
344                "corrupt. Corrupt inode 0x%lx. Run chkdsk.",
345                (unsigned long long)vcn, dir_ni->mft_no);
346        goto unm_err_out;
347    }
348    if (sle64_to_cpu(ia->index_block_vcn) != vcn) {
349        ntfs_error(sb, "Actual VCN (0x%llx) of index buffer is "
350                "different from expected VCN (0x%llx). "
351                "Directory inode 0x%lx is corrupt or driver "
352                "bug.", (unsigned long long)
353                sle64_to_cpu(ia->index_block_vcn),
354                (unsigned long long)vcn, dir_ni->mft_no);
355        goto unm_err_out;
356    }
357    if (le32_to_cpu(ia->index.allocated_size) + 0x18 !=
358            dir_ni->itype.index.block_size) {
359        ntfs_error(sb, "Index buffer (VCN 0x%llx) of directory inode "
360                "0x%lx has a size (%u) differing from the "
361                "directory specified size (%u). Directory "
362                "inode is corrupt or driver bug.",
363                (unsigned long long)vcn, dir_ni->mft_no,
364                le32_to_cpu(ia->index.allocated_size) + 0x18,
365                dir_ni->itype.index.block_size);
366        goto unm_err_out;
367    }
368    index_end = (u8*)ia + dir_ni->itype.index.block_size;
369    if (index_end > kaddr + PAGE_CACHE_SIZE) {
370        ntfs_error(sb, "Index buffer (VCN 0x%llx) of directory inode "
371                "0x%lx crosses page boundary. Impossible! "
372                "Cannot access! This is probably a bug in the "
373                "driver.", (unsigned long long)vcn,
374                dir_ni->mft_no);
375        goto unm_err_out;
376    }
377    index_end = (u8*)&ia->index + le32_to_cpu(ia->index.index_length);
378    if (index_end > (u8*)ia + dir_ni->itype.index.block_size) {
379        ntfs_error(sb, "Size of index buffer (VCN 0x%llx) of directory "
380                "inode 0x%lx exceeds maximum size.",
381                (unsigned long long)vcn, dir_ni->mft_no);
382        goto unm_err_out;
383    }
384    /* The first index entry. */
385    ie = (INDEX_ENTRY*)((u8*)&ia->index +
386            le32_to_cpu(ia->index.entries_offset));
387    /*
388     * Iterate similar to above big loop but applied to index buffer, thus
389     * loop until we exceed valid memory (corruption case) or until we
390     * reach the last entry.
391     */
392    for (;; ie = (INDEX_ENTRY*)((u8*)ie + le16_to_cpu(ie->length))) {
393        /* Bounds check. */
394        if ((u8*)ie < (u8*)ia || (u8*)ie +
395                sizeof(INDEX_ENTRY_HEADER) > index_end ||
396                (u8*)ie + le16_to_cpu(ie->key_length) >
397                index_end) {
398            ntfs_error(sb, "Index entry out of bounds in "
399                    "directory inode 0x%lx.",
400                    dir_ni->mft_no);
401            goto unm_err_out;
402        }
403        /*
404         * The last entry cannot contain a name. It can however contain
405         * a pointer to a child node in the B+tree so we just break out.
406         */
407        if (ie->flags & INDEX_ENTRY_END)
408            break;
409        /*
410         * We perform a case sensitive comparison and if that matches
411         * we are done and return the mft reference of the inode (i.e.
412         * the inode number together with the sequence number for
413         * consistency checking). We convert it to cpu format before
414         * returning.
415         */
416        if (ntfs_are_names_equal(uname, uname_len,
417                (ntfschar*)&ie->key.file_name.file_name,
418                ie->key.file_name.file_name_length,
419                CASE_SENSITIVE, vol->upcase, vol->upcase_len)) {
420found_it2:
421            /*
422             * We have a perfect match, so we don't need to care
423             * about having matched imperfectly before, so we can
424             * free name and set *res to NULL.
425             * However, if the perfect match is a short file name,
426             * we need to signal this through *res, so that
427             * ntfs_lookup() can fix dcache aliasing issues.
428             * As an optimization we just reuse an existing
429             * allocation of *res.
430             */
431            if (ie->key.file_name.file_name_type == FILE_NAME_DOS) {
432                if (!name) {
433                    name = kmalloc(sizeof(ntfs_name),
434                            GFP_NOFS);
435                    if (!name) {
436                        err = -ENOMEM;
437                        goto unm_err_out;
438                    }
439                }
440                name->mref = le64_to_cpu(
441                        ie->data.dir.indexed_file);
442                name->type = FILE_NAME_DOS;
443                name->len = 0;
444                *res = name;
445            } else {
446                kfree(name);
447                *res = NULL;
448            }
449            mref = le64_to_cpu(ie->data.dir.indexed_file);
450            unlock_page(page);
451            ntfs_unmap_page(page);
452            return mref;
453        }
454        /*
455         * For a case insensitive mount, we also perform a case
456         * insensitive comparison (provided the file name is not in the
457         * POSIX namespace). If the comparison matches, and the name is
458         * in the WIN32 namespace, we cache the filename in *res so
459         * that the caller, ntfs_lookup(), can work on it. If the
460         * comparison matches, and the name is in the DOS namespace, we
461         * only cache the mft reference and the file name type (we set
462         * the name length to zero for simplicity).
463         */
464        if (!NVolCaseSensitive(vol) &&
465                ie->key.file_name.file_name_type &&
466                ntfs_are_names_equal(uname, uname_len,
467                (ntfschar*)&ie->key.file_name.file_name,
468                ie->key.file_name.file_name_length,
469                IGNORE_CASE, vol->upcase, vol->upcase_len)) {
470            int name_size = sizeof(ntfs_name);
471            u8 type = ie->key.file_name.file_name_type;
472            u8 len = ie->key.file_name.file_name_length;
473
474            /* Only one case insensitive matching name allowed. */
475            if (name) {
476                ntfs_error(sb, "Found already allocated name "
477                        "in phase 2. Please run chkdsk "
478                        "and if that doesn't find any "
479                        "errors please report you saw "
480                        "this message to "
481                        "linux-ntfs-dev@lists."
482                        "sourceforge.net.");
483                unlock_page(page);
484                ntfs_unmap_page(page);
485                goto dir_err_out;
486            }
487
488            if (type != FILE_NAME_DOS)
489                name_size += len * sizeof(ntfschar);
490            name = kmalloc(name_size, GFP_NOFS);
491            if (!name) {
492                err = -ENOMEM;
493                goto unm_err_out;
494            }
495            name->mref = le64_to_cpu(ie->data.dir.indexed_file);
496            name->type = type;
497            if (type != FILE_NAME_DOS) {
498                name->len = len;
499                memcpy(name->name, ie->key.file_name.file_name,
500                        len * sizeof(ntfschar));
501            } else
502                name->len = 0;
503            *res = name;
504        }
505        /*
506         * Not a perfect match, need to do full blown collation so we
507         * know which way in the B+tree we have to go.
508         */
509        rc = ntfs_collate_names(uname, uname_len,
510                (ntfschar*)&ie->key.file_name.file_name,
511                ie->key.file_name.file_name_length, 1,
512                IGNORE_CASE, vol->upcase, vol->upcase_len);
513        /*
514         * If uname collates before the name of the current entry, there
515         * is definitely no such name in this index but we might need to
516         * descend into the B+tree so we just break out of the loop.
517         */
518        if (rc == -1)
519            break;
520        /* The names are not equal, continue the search. */
521        if (rc)
522            continue;
523        /*
524         * Names match with case insensitive comparison, now try the
525         * case sensitive comparison, which is required for proper
526         * collation.
527         */
528        rc = ntfs_collate_names(uname, uname_len,
529                (ntfschar*)&ie->key.file_name.file_name,
530                ie->key.file_name.file_name_length, 1,
531                CASE_SENSITIVE, vol->upcase, vol->upcase_len);
532        if (rc == -1)
533            break;
534        if (rc)
535            continue;
536        /*
537         * Perfect match, this will never happen as the
538         * ntfs_are_names_equal() call will have gotten a match but we
539         * still treat it correctly.
540         */
541        goto found_it2;
542    }
543    /*
544     * We have finished with this index buffer without success. Check for
545     * the presence of a child node.
546     */
547    if (ie->flags & INDEX_ENTRY_NODE) {
548        if ((ia->index.flags & NODE_MASK) == LEAF_NODE) {
549            ntfs_error(sb, "Index entry with child node found in "
550                    "a leaf node in directory inode 0x%lx.",
551                    dir_ni->mft_no);
552            goto unm_err_out;
553        }
554        /* Child node present, descend into it. */
555        old_vcn = vcn;
556        vcn = sle64_to_cpup((sle64*)((u8*)ie +
557                le16_to_cpu(ie->length) - 8));
558        if (vcn >= 0) {
559            /* If vcn is in the same page cache page as old_vcn we
560             * recycle the mapped page. */
561            if (old_vcn << vol->cluster_size_bits >>
562                    PAGE_CACHE_SHIFT == vcn <<
563                    vol->cluster_size_bits >>
564                    PAGE_CACHE_SHIFT)
565                goto fast_descend_into_child_node;
566            unlock_page(page);
567            ntfs_unmap_page(page);
568            goto descend_into_child_node;
569        }
570        ntfs_error(sb, "Negative child node vcn in directory inode "
571                "0x%lx.", dir_ni->mft_no);
572        goto unm_err_out;
573    }
574    /*
575     * No child node present, return -ENOENT, unless we have got a matching
576     * name cached in name in which case return the mft reference
577     * associated with it.
578     */
579    if (name) {
580        unlock_page(page);
581        ntfs_unmap_page(page);
582        return name->mref;
583    }
584    ntfs_debug("Entry not found.");
585    err = -ENOENT;
586unm_err_out:
587    unlock_page(page);
588    ntfs_unmap_page(page);
589err_out:
590    if (!err)
591        err = -EIO;
592    if (ctx)
593        ntfs_attr_put_search_ctx(ctx);
594    if (m)
595        unmap_mft_record(dir_ni);
596    if (name) {
597        kfree(name);
598        *res = NULL;
599    }
600    return ERR_MREF(err);
601dir_err_out:
602    ntfs_error(sb, "Corrupt directory. Aborting lookup.");
603    goto err_out;
604}
605
606#if 0
607
608// TODO: (AIA)
609// The algorithm embedded in this code will be required for the time when we
610// want to support adding of entries to directories, where we require correct
611// collation of file names in order not to cause corruption of the filesystem.
612
613/**
614 * ntfs_lookup_inode_by_name - find an inode in a directory given its name
615 * @dir_ni: ntfs inode of the directory in which to search for the name
616 * @uname: Unicode name for which to search in the directory
617 * @uname_len: length of the name @uname in Unicode characters
618 *
619 * Look for an inode with name @uname in the directory with inode @dir_ni.
620 * ntfs_lookup_inode_by_name() walks the contents of the directory looking for
621 * the Unicode name. If the name is found in the directory, the corresponding
622 * inode number (>= 0) is returned as a mft reference in cpu format, i.e. it
623 * is a 64-bit number containing the sequence number.
624 *
625 * On error, a negative value is returned corresponding to the error code. In
626 * particular if the inode is not found -ENOENT is returned. Note that you
627 * can't just check the return value for being negative, you have to check the
628 * inode number for being negative which you can extract using MREC(return
629 * value).
630 *
631 * Note, @uname_len does not include the (optional) terminating NULL character.
632 */
633u64 ntfs_lookup_inode_by_name(ntfs_inode *dir_ni, const ntfschar *uname,
634        const int uname_len)
635{
636    ntfs_volume *vol = dir_ni->vol;
637    struct super_block *sb = vol->sb;
638    MFT_RECORD *m;
639    INDEX_ROOT *ir;
640    INDEX_ENTRY *ie;
641    INDEX_ALLOCATION *ia;
642    u8 *index_end;
643    u64 mref;
644    ntfs_attr_search_ctx *ctx;
645    int err, rc;
646    IGNORE_CASE_BOOL ic;
647    VCN vcn, old_vcn;
648    struct address_space *ia_mapping;
649    struct page *page;
650    u8 *kaddr;
651
652    /* Get hold of the mft record for the directory. */
653    m = map_mft_record(dir_ni);
654    if (IS_ERR(m)) {
655        ntfs_error(sb, "map_mft_record() failed with error code %ld.",
656                -PTR_ERR(m));
657        return ERR_MREF(PTR_ERR(m));
658    }
659    ctx = ntfs_attr_get_search_ctx(dir_ni, m);
660    if (!ctx) {
661        err = -ENOMEM;
662        goto err_out;
663    }
664    /* Find the index root attribute in the mft record. */
665    err = ntfs_attr_lookup(AT_INDEX_ROOT, I30, 4, CASE_SENSITIVE, 0, NULL,
666            0, ctx);
667    if (unlikely(err)) {
668        if (err == -ENOENT) {
669            ntfs_error(sb, "Index root attribute missing in "
670                    "directory inode 0x%lx.",
671                    dir_ni->mft_no);
672            err = -EIO;
673        }
674        goto err_out;
675    }
676    /* Get to the index root value (it's been verified in read_inode). */
677    ir = (INDEX_ROOT*)((u8*)ctx->attr +
678            le16_to_cpu(ctx->attr->data.resident.value_offset));
679    index_end = (u8*)&ir->index + le32_to_cpu(ir->index.index_length);
680    /* The first index entry. */
681    ie = (INDEX_ENTRY*)((u8*)&ir->index +
682            le32_to_cpu(ir->index.entries_offset));
683    /*
684     * Loop until we exceed valid memory (corruption case) or until we
685     * reach the last entry.
686     */
687    for (;; ie = (INDEX_ENTRY*)((u8*)ie + le16_to_cpu(ie->length))) {
688        /* Bounds checks. */
689        if ((u8*)ie < (u8*)ctx->mrec || (u8*)ie +
690                sizeof(INDEX_ENTRY_HEADER) > index_end ||
691                (u8*)ie + le16_to_cpu(ie->key_length) >
692                index_end)
693            goto dir_err_out;
694        /*
695         * The last entry cannot contain a name. It can however contain
696         * a pointer to a child node in the B+tree so we just break out.
697         */
698        if (ie->flags & INDEX_ENTRY_END)
699            break;
700        /*
701         * If the current entry has a name type of POSIX, the name is
702         * case sensitive and not otherwise. This has the effect of us
703         * not being able to access any POSIX file names which collate
704         * after the non-POSIX one when they only differ in case, but
705         * anyone doing screwy stuff like that deserves to burn in
706         * hell... Doing that kind of stuff on NT4 actually causes
707         * corruption on the partition even when using SP6a and Linux
708         * is not involved at all.
709         */
710        ic = ie->key.file_name.file_name_type ? IGNORE_CASE :
711                CASE_SENSITIVE;
712        /*
713         * If the names match perfectly, we are done and return the
714         * mft reference of the inode (i.e. the inode number together
715         * with the sequence number for consistency checking. We
716         * convert it to cpu format before returning.
717         */
718        if (ntfs_are_names_equal(uname, uname_len,
719                (ntfschar*)&ie->key.file_name.file_name,
720                ie->key.file_name.file_name_length, ic,
721                vol->upcase, vol->upcase_len)) {
722found_it:
723            mref = le64_to_cpu(ie->data.dir.indexed_file);
724            ntfs_attr_put_search_ctx(ctx);
725            unmap_mft_record(dir_ni);
726            return mref;
727        }
728        /*
729         * Not a perfect match, need to do full blown collation so we
730         * know which way in the B+tree we have to go.
731         */
732        rc = ntfs_collate_names(uname, uname_len,
733                (ntfschar*)&ie->key.file_name.file_name,
734                ie->key.file_name.file_name_length, 1,
735                IGNORE_CASE, vol->upcase, vol->upcase_len);
736        /*
737         * If uname collates before the name of the current entry, there
738         * is definitely no such name in this index but we might need to
739         * descend into the B+tree so we just break out of the loop.
740         */
741        if (rc == -1)
742            break;
743        /* The names are not equal, continue the search. */
744        if (rc)
745            continue;
746        /*
747         * Names match with case insensitive comparison, now try the
748         * case sensitive comparison, which is required for proper
749         * collation.
750         */
751        rc = ntfs_collate_names(uname, uname_len,
752                (ntfschar*)&ie->key.file_name.file_name,
753                ie->key.file_name.file_name_length, 1,
754                CASE_SENSITIVE, vol->upcase, vol->upcase_len);
755        if (rc == -1)
756            break;
757        if (rc)
758            continue;
759        /*
760         * Perfect match, this will never happen as the
761         * ntfs_are_names_equal() call will have gotten a match but we
762         * still treat it correctly.
763         */
764        goto found_it;
765    }
766    /*
767     * We have finished with this index without success. Check for the
768     * presence of a child node.
769     */
770    if (!(ie->flags & INDEX_ENTRY_NODE)) {
771        /* No child node, return -ENOENT. */
772        err = -ENOENT;
773        goto err_out;
774    } /* Child node present, descend into it. */
775    /* Consistency check: Verify that an index allocation exists. */
776    if (!NInoIndexAllocPresent(dir_ni)) {
777        ntfs_error(sb, "No index allocation attribute but index entry "
778                "requires one. Directory inode 0x%lx is "
779                "corrupt or driver bug.", dir_ni->mft_no);
780        goto err_out;
781    }
782    /* Get the starting vcn of the index_block holding the child node. */
783    vcn = sle64_to_cpup((u8*)ie + le16_to_cpu(ie->length) - 8);
784    ia_mapping = VFS_I(dir_ni)->i_mapping;
785    /*
786     * We are done with the index root and the mft record. Release them,
787     * otherwise we deadlock with ntfs_map_page().
788     */
789    ntfs_attr_put_search_ctx(ctx);
790    unmap_mft_record(dir_ni);
791    m = NULL;
792    ctx = NULL;
793descend_into_child_node:
794    /*
795     * Convert vcn to index into the index allocation attribute in units
796     * of PAGE_CACHE_SIZE and map the page cache page, reading it from
797     * disk if necessary.
798     */
799    page = ntfs_map_page(ia_mapping, vcn <<
800            dir_ni->itype.index.vcn_size_bits >> PAGE_CACHE_SHIFT);
801    if (IS_ERR(page)) {
802        ntfs_error(sb, "Failed to map directory index page, error %ld.",
803                -PTR_ERR(page));
804        err = PTR_ERR(page);
805        goto err_out;
806    }
807    lock_page(page);
808    kaddr = (u8*)page_address(page);
809fast_descend_into_child_node:
810    /* Get to the index allocation block. */
811    ia = (INDEX_ALLOCATION*)(kaddr + ((vcn <<
812            dir_ni->itype.index.vcn_size_bits) & ~PAGE_CACHE_MASK));
813    /* Bounds checks. */
814    if ((u8*)ia < kaddr || (u8*)ia > kaddr + PAGE_CACHE_SIZE) {
815        ntfs_error(sb, "Out of bounds check failed. Corrupt directory "
816                "inode 0x%lx or driver bug.", dir_ni->mft_no);
817        goto unm_err_out;
818    }
819    /* Catch multi sector transfer fixup errors. */
820    if (unlikely(!ntfs_is_indx_record(ia->magic))) {
821        ntfs_error(sb, "Directory index record with vcn 0x%llx is "
822                "corrupt. Corrupt inode 0x%lx. Run chkdsk.",
823                (unsigned long long)vcn, dir_ni->mft_no);
824        goto unm_err_out;
825    }
826    if (sle64_to_cpu(ia->index_block_vcn) != vcn) {
827        ntfs_error(sb, "Actual VCN (0x%llx) of index buffer is "
828                "different from expected VCN (0x%llx). "
829                "Directory inode 0x%lx is corrupt or driver "
830                "bug.", (unsigned long long)
831                sle64_to_cpu(ia->index_block_vcn),
832                (unsigned long long)vcn, dir_ni->mft_no);
833        goto unm_err_out;
834    }
835    if (le32_to_cpu(ia->index.allocated_size) + 0x18 !=
836            dir_ni->itype.index.block_size) {
837        ntfs_error(sb, "Index buffer (VCN 0x%llx) of directory inode "
838                "0x%lx has a size (%u) differing from the "
839                "directory specified size (%u). Directory "
840                "inode is corrupt or driver bug.",
841                (unsigned long long)vcn, dir_ni->mft_no,
842                le32_to_cpu(ia->index.allocated_size) + 0x18,
843                dir_ni->itype.index.block_size);
844        goto unm_err_out;
845    }
846    index_end = (u8*)ia + dir_ni->itype.index.block_size;
847    if (index_end > kaddr + PAGE_CACHE_SIZE) {
848        ntfs_error(sb, "Index buffer (VCN 0x%llx) of directory inode "
849                "0x%lx crosses page boundary. Impossible! "
850                "Cannot access! This is probably a bug in the "
851                "driver.", (unsigned long long)vcn,
852                dir_ni->mft_no);
853        goto unm_err_out;
854    }
855    index_end = (u8*)&ia->index + le32_to_cpu(ia->index.index_length);
856    if (index_end > (u8*)ia + dir_ni->itype.index.block_size) {
857        ntfs_error(sb, "Size of index buffer (VCN 0x%llx) of directory "
858                "inode 0x%lx exceeds maximum size.",
859                (unsigned long long)vcn, dir_ni->mft_no);
860        goto unm_err_out;
861    }
862    /* The first index entry. */
863    ie = (INDEX_ENTRY*)((u8*)&ia->index +
864            le32_to_cpu(ia->index.entries_offset));
865    /*
866     * Iterate similar to above big loop but applied to index buffer, thus
867     * loop until we exceed valid memory (corruption case) or until we
868     * reach the last entry.
869     */
870    for (;; ie = (INDEX_ENTRY*)((u8*)ie + le16_to_cpu(ie->length))) {
871        /* Bounds check. */
872        if ((u8*)ie < (u8*)ia || (u8*)ie +
873                sizeof(INDEX_ENTRY_HEADER) > index_end ||
874                (u8*)ie + le16_to_cpu(ie->key_length) >
875                index_end) {
876            ntfs_error(sb, "Index entry out of bounds in "
877                    "directory inode 0x%lx.",
878                    dir_ni->mft_no);
879            goto unm_err_out;
880        }
881        /*
882         * The last entry cannot contain a name. It can however contain
883         * a pointer to a child node in the B+tree so we just break out.
884         */
885        if (ie->flags & INDEX_ENTRY_END)
886            break;
887        /*
888         * If the current entry has a name type of POSIX, the name is
889         * case sensitive and not otherwise. This has the effect of us
890         * not being able to access any POSIX file names which collate
891         * after the non-POSIX one when they only differ in case, but
892         * anyone doing screwy stuff like that deserves to burn in
893         * hell... Doing that kind of stuff on NT4 actually causes
894         * corruption on the partition even when using SP6a and Linux
895         * is not involved at all.
896         */
897        ic = ie->key.file_name.file_name_type ? IGNORE_CASE :
898                CASE_SENSITIVE;
899        /*
900         * If the names match perfectly, we are done and return the
901         * mft reference of the inode (i.e. the inode number together
902         * with the sequence number for consistency checking. We
903         * convert it to cpu format before returning.
904         */
905        if (ntfs_are_names_equal(uname, uname_len,
906                (ntfschar*)&ie->key.file_name.file_name,
907                ie->key.file_name.file_name_length, ic,
908                vol->upcase, vol->upcase_len)) {
909found_it2:
910            mref = le64_to_cpu(ie->data.dir.indexed_file);
911            unlock_page(page);
912            ntfs_unmap_page(page);
913            return mref;
914        }
915        /*
916         * Not a perfect match, need to do full blown collation so we
917         * know which way in the B+tree we have to go.
918         */
919        rc = ntfs_collate_names(uname, uname_len,
920                (ntfschar*)&ie->key.file_name.file_name,
921                ie->key.file_name.file_name_length, 1,
922                IGNORE_CASE, vol->upcase, vol->upcase_len);
923        /*
924         * If uname collates before the name of the current entry, there
925         * is definitely no such name in this index but we might need to
926         * descend into the B+tree so we just break out of the loop.
927         */
928        if (rc == -1)
929            break;
930        /* The names are not equal, continue the search. */
931        if (rc)
932            continue;
933        /*
934         * Names match with case insensitive comparison, now try the
935         * case sensitive comparison, which is required for proper
936         * collation.
937         */
938        rc = ntfs_collate_names(uname, uname_len,
939                (ntfschar*)&ie->key.file_name.file_name,
940                ie->key.file_name.file_name_length, 1,
941                CASE_SENSITIVE, vol->upcase, vol->upcase_len);
942        if (rc == -1)
943            break;
944        if (rc)
945            continue;
946        /*
947         * Perfect match, this will never happen as the
948         * ntfs_are_names_equal() call will have gotten a match but we
949         * still treat it correctly.
950         */
951        goto found_it2;
952    }
953    /*
954     * We have finished with this index buffer without success. Check for
955     * the presence of a child node.
956     */
957    if (ie->flags & INDEX_ENTRY_NODE) {
958        if ((ia->index.flags & NODE_MASK) == LEAF_NODE) {
959            ntfs_error(sb, "Index entry with child node found in "
960                    "a leaf node in directory inode 0x%lx.",
961                    dir_ni->mft_no);
962            goto unm_err_out;
963        }
964        /* Child node present, descend into it. */
965        old_vcn = vcn;
966        vcn = sle64_to_cpup((u8*)ie + le16_to_cpu(ie->length) - 8);
967        if (vcn >= 0) {
968            /* If vcn is in the same page cache page as old_vcn we
969             * recycle the mapped page. */
970            if (old_vcn << vol->cluster_size_bits >>
971                    PAGE_CACHE_SHIFT == vcn <<
972                    vol->cluster_size_bits >>
973                    PAGE_CACHE_SHIFT)
974                goto fast_descend_into_child_node;
975            unlock_page(page);
976            ntfs_unmap_page(page);
977            goto descend_into_child_node;
978        }
979        ntfs_error(sb, "Negative child node vcn in directory inode "
980                "0x%lx.", dir_ni->mft_no);
981        goto unm_err_out;
982    }
983    /* No child node, return -ENOENT. */
984    ntfs_debug("Entry not found.");
985    err = -ENOENT;
986unm_err_out:
987    unlock_page(page);
988    ntfs_unmap_page(page);
989err_out:
990    if (!err)
991        err = -EIO;
992    if (ctx)
993        ntfs_attr_put_search_ctx(ctx);
994    if (m)
995        unmap_mft_record(dir_ni);
996    return ERR_MREF(err);
997dir_err_out:
998    ntfs_error(sb, "Corrupt directory. Aborting lookup.");
999    goto err_out;
1000}
1001
1002#endif
1003
1004/**
1005 * ntfs_filldir - ntfs specific filldir method
1006 * @vol: current ntfs volume
1007 * @fpos: position in the directory
1008 * @ndir: ntfs inode of current directory
1009 * @ia_page: page in which the index allocation buffer @ie is in resides
1010 * @ie: current index entry
1011 * @name: buffer to use for the converted name
1012 * @dirent: vfs filldir callback context
1013 * @filldir: vfs filldir callback
1014 *
1015 * Convert the Unicode @name to the loaded NLS and pass it to the @filldir
1016 * callback.
1017 *
1018 * If @ia_page is not NULL it is the locked page containing the index
1019 * allocation block containing the index entry @ie.
1020 *
1021 * Note, we drop (and then reacquire) the page lock on @ia_page across the
1022 * @filldir() call otherwise we would deadlock with NFSd when it calls ->lookup
1023 * since ntfs_lookup() will lock the same page. As an optimization, we do not
1024 * retake the lock if we are returning a non-zero value as ntfs_readdir()
1025 * would need to drop the lock immediately anyway.
1026 */
1027static inline int ntfs_filldir(ntfs_volume *vol, loff_t fpos,
1028        ntfs_inode *ndir, struct page *ia_page, INDEX_ENTRY *ie,
1029        u8 *name, void *dirent, filldir_t filldir)
1030{
1031    unsigned long mref;
1032    int name_len, rc;
1033    unsigned dt_type;
1034    FILE_NAME_TYPE_FLAGS name_type;
1035
1036    name_type = ie->key.file_name.file_name_type;
1037    if (name_type == FILE_NAME_DOS) {
1038        ntfs_debug("Skipping DOS name space entry.");
1039        return 0;
1040    }
1041    if (MREF_LE(ie->data.dir.indexed_file) == FILE_root) {
1042        ntfs_debug("Skipping root directory self reference entry.");
1043        return 0;
1044    }
1045    if (MREF_LE(ie->data.dir.indexed_file) < FILE_first_user &&
1046            !NVolShowSystemFiles(vol)) {
1047        ntfs_debug("Skipping system file.");
1048        return 0;
1049    }
1050    name_len = ntfs_ucstonls(vol, (ntfschar*)&ie->key.file_name.file_name,
1051            ie->key.file_name.file_name_length, &name,
1052            NTFS_MAX_NAME_LEN * NLS_MAX_CHARSET_SIZE + 1);
1053    if (name_len <= 0) {
1054        ntfs_warning(vol->sb, "Skipping unrepresentable inode 0x%llx.",
1055                (long long)MREF_LE(ie->data.dir.indexed_file));
1056        return 0;
1057    }
1058    if (ie->key.file_name.file_attributes &
1059            FILE_ATTR_DUP_FILE_NAME_INDEX_PRESENT)
1060        dt_type = DT_DIR;
1061    else
1062        dt_type = DT_REG;
1063    mref = MREF_LE(ie->data.dir.indexed_file);
1064    /*
1065     * Drop the page lock otherwise we deadlock with NFS when it calls
1066     * ->lookup since ntfs_lookup() will lock the same page.
1067     */
1068    if (ia_page)
1069        unlock_page(ia_page);
1070    ntfs_debug("Calling filldir for %s with len %i, fpos 0x%llx, inode "
1071            "0x%lx, DT_%s.", name, name_len, fpos, mref,
1072            dt_type == DT_DIR ? "DIR" : "REG");
1073    rc = filldir(dirent, name, name_len, fpos, mref, dt_type);
1074    /* Relock the page but not if we are aborting ->readdir. */
1075    if (!rc && ia_page)
1076        lock_page(ia_page);
1077    return rc;
1078}
1079
1080/*
1081 * We use the same basic approach as the old NTFS driver, i.e. we parse the
1082 * index root entries and then the index allocation entries that are marked
1083 * as in use in the index bitmap.
1084 *
1085 * While this will return the names in random order this doesn't matter for
1086 * ->readdir but OTOH results in a faster ->readdir.
1087 *
1088 * VFS calls ->readdir without BKL but with i_mutex held. This protects the VFS
1089 * parts (e.g. ->f_pos and ->i_size, and it also protects against directory
1090 * modifications).
1091 *
1092 * Locking: - Caller must hold i_mutex on the directory.
1093 * - Each page cache page in the index allocation mapping must be
1094 * locked whilst being accessed otherwise we may find a corrupt
1095 * page due to it being under ->writepage at the moment which
1096 * applies the mst protection fixups before writing out and then
1097 * removes them again after the write is complete after which it
1098 * unlocks the page.
1099 */
1100static int ntfs_readdir(struct file *filp, void *dirent, filldir_t filldir)
1101{
1102    s64 ia_pos, ia_start, prev_ia_pos, bmp_pos;
1103    loff_t fpos, i_size;
1104    struct inode *bmp_vi, *vdir = filp->f_path.dentry->d_inode;
1105    struct super_block *sb = vdir->i_sb;
1106    ntfs_inode *ndir = NTFS_I(vdir);
1107    ntfs_volume *vol = NTFS_SB(sb);
1108    MFT_RECORD *m;
1109    INDEX_ROOT *ir = NULL;
1110    INDEX_ENTRY *ie;
1111    INDEX_ALLOCATION *ia;
1112    u8 *name = NULL;
1113    int rc, err, ir_pos, cur_bmp_pos;
1114    struct address_space *ia_mapping, *bmp_mapping;
1115    struct page *bmp_page = NULL, *ia_page = NULL;
1116    u8 *kaddr, *bmp, *index_end;
1117    ntfs_attr_search_ctx *ctx;
1118
1119    fpos = filp->f_pos;
1120    ntfs_debug("Entering for inode 0x%lx, fpos 0x%llx.",
1121            vdir->i_ino, fpos);
1122    rc = err = 0;
1123    /* Are we at end of dir yet? */
1124    i_size = i_size_read(vdir);
1125    if (fpos >= i_size + vol->mft_record_size)
1126        goto done;
1127    /* Emulate . and .. for all directories. */
1128    if (!fpos) {
1129        ntfs_debug("Calling filldir for . with len 1, fpos 0x0, "
1130                "inode 0x%lx, DT_DIR.", vdir->i_ino);
1131        rc = filldir(dirent, ".", 1, fpos, vdir->i_ino, DT_DIR);
1132        if (rc)
1133            goto done;
1134        fpos++;
1135    }
1136    if (fpos == 1) {
1137        ntfs_debug("Calling filldir for .. with len 2, fpos 0x1, "
1138                "inode 0x%lx, DT_DIR.",
1139                (unsigned long)parent_ino(filp->f_path.dentry));
1140        rc = filldir(dirent, "..", 2, fpos,
1141                parent_ino(filp->f_path.dentry), DT_DIR);
1142        if (rc)
1143            goto done;
1144        fpos++;
1145    }
1146    m = NULL;
1147    ctx = NULL;
1148    /*
1149     * Allocate a buffer to store the current name being processed
1150     * converted to format determined by current NLS.
1151     */
1152    name = kmalloc(NTFS_MAX_NAME_LEN * NLS_MAX_CHARSET_SIZE + 1, GFP_NOFS);
1153    if (unlikely(!name)) {
1154        err = -ENOMEM;
1155        goto err_out;
1156    }
1157    /* Are we jumping straight into the index allocation attribute? */
1158    if (fpos >= vol->mft_record_size)
1159        goto skip_index_root;
1160    /* Get hold of the mft record for the directory. */
1161    m = map_mft_record(ndir);
1162    if (IS_ERR(m)) {
1163        err = PTR_ERR(m);
1164        m = NULL;
1165        goto err_out;
1166    }
1167    ctx = ntfs_attr_get_search_ctx(ndir, m);
1168    if (unlikely(!ctx)) {
1169        err = -ENOMEM;
1170        goto err_out;
1171    }
1172    /* Get the offset into the index root attribute. */
1173    ir_pos = (s64)fpos;
1174    /* Find the index root attribute in the mft record. */
1175    err = ntfs_attr_lookup(AT_INDEX_ROOT, I30, 4, CASE_SENSITIVE, 0, NULL,
1176            0, ctx);
1177    if (unlikely(err)) {
1178        ntfs_error(sb, "Index root attribute missing in directory "
1179                "inode 0x%lx.", vdir->i_ino);
1180        goto err_out;
1181    }
1182    /*
1183     * Copy the index root attribute value to a buffer so that we can put
1184     * the search context and unmap the mft record before calling the
1185     * filldir() callback. We need to do this because of NFSd which calls
1186     * ->lookup() from its filldir callback() and this causes NTFS to
1187     * deadlock as ntfs_lookup() maps the mft record of the directory and
1188     * we have got it mapped here already. The only solution is for us to
1189     * unmap the mft record here so that a call to ntfs_lookup() is able to
1190     * map the mft record without deadlocking.
1191     */
1192    rc = le32_to_cpu(ctx->attr->data.resident.value_length);
1193    ir = kmalloc(rc, GFP_NOFS);
1194    if (unlikely(!ir)) {
1195        err = -ENOMEM;
1196        goto err_out;
1197    }
1198    /* Copy the index root value (it has been verified in read_inode). */
1199    memcpy(ir, (u8*)ctx->attr +
1200            le16_to_cpu(ctx->attr->data.resident.value_offset), rc);
1201    ntfs_attr_put_search_ctx(ctx);
1202    unmap_mft_record(ndir);
1203    ctx = NULL;
1204    m = NULL;
1205    index_end = (u8*)&ir->index + le32_to_cpu(ir->index.index_length);
1206    /* The first index entry. */
1207    ie = (INDEX_ENTRY*)((u8*)&ir->index +
1208            le32_to_cpu(ir->index.entries_offset));
1209    /*
1210     * Loop until we exceed valid memory (corruption case) or until we
1211     * reach the last entry or until filldir tells us it has had enough
1212     * or signals an error (both covered by the rc test).
1213     */
1214    for (;; ie = (INDEX_ENTRY*)((u8*)ie + le16_to_cpu(ie->length))) {
1215        ntfs_debug("In index root, offset 0x%zx.", (u8*)ie - (u8*)ir);
1216        /* Bounds checks. */
1217        if (unlikely((u8*)ie < (u8*)ir || (u8*)ie +
1218                sizeof(INDEX_ENTRY_HEADER) > index_end ||
1219                (u8*)ie + le16_to_cpu(ie->key_length) >
1220                index_end))
1221            goto err_out;
1222        /* The last entry cannot contain a name. */
1223        if (ie->flags & INDEX_ENTRY_END)
1224            break;
1225        /* Skip index root entry if continuing previous readdir. */
1226        if (ir_pos > (u8*)ie - (u8*)ir)
1227            continue;
1228        /* Advance the position even if going to skip the entry. */
1229        fpos = (u8*)ie - (u8*)ir;
1230        /* Submit the name to the filldir callback. */
1231        rc = ntfs_filldir(vol, fpos, ndir, NULL, ie, name, dirent,
1232                filldir);
1233        if (rc) {
1234            kfree(ir);
1235            goto abort;
1236        }
1237    }
1238    /* We are done with the index root and can free the buffer. */
1239    kfree(ir);
1240    ir = NULL;
1241    /* If there is no index allocation attribute we are finished. */
1242    if (!NInoIndexAllocPresent(ndir))
1243        goto EOD;
1244    /* Advance fpos to the beginning of the index allocation. */
1245    fpos = vol->mft_record_size;
1246skip_index_root:
1247    kaddr = NULL;
1248    prev_ia_pos = -1LL;
1249    /* Get the offset into the index allocation attribute. */
1250    ia_pos = (s64)fpos - vol->mft_record_size;
1251    ia_mapping = vdir->i_mapping;
1252    ntfs_debug("Inode 0x%lx, getting index bitmap.", vdir->i_ino);
1253    bmp_vi = ntfs_attr_iget(vdir, AT_BITMAP, I30, 4);
1254    if (IS_ERR(bmp_vi)) {
1255        ntfs_error(sb, "Failed to get bitmap attribute.");
1256        err = PTR_ERR(bmp_vi);
1257        goto err_out;
1258    }
1259    bmp_mapping = bmp_vi->i_mapping;
1260    /* Get the starting bitmap bit position and sanity check it. */
1261    bmp_pos = ia_pos >> ndir->itype.index.block_size_bits;
1262    if (unlikely(bmp_pos >> 3 >= i_size_read(bmp_vi))) {
1263        ntfs_error(sb, "Current index allocation position exceeds "
1264                "index bitmap size.");
1265        goto iput_err_out;
1266    }
1267    /* Get the starting bit position in the current bitmap page. */
1268    cur_bmp_pos = bmp_pos & ((PAGE_CACHE_SIZE * 8) - 1);
1269    bmp_pos &= ~(u64)((PAGE_CACHE_SIZE * 8) - 1);
1270get_next_bmp_page:
1271    ntfs_debug("Reading bitmap with page index 0x%llx, bit ofs 0x%llx",
1272            (unsigned long long)bmp_pos >> (3 + PAGE_CACHE_SHIFT),
1273            (unsigned long long)bmp_pos &
1274            (unsigned long long)((PAGE_CACHE_SIZE * 8) - 1));
1275    bmp_page = ntfs_map_page(bmp_mapping,
1276            bmp_pos >> (3 + PAGE_CACHE_SHIFT));
1277    if (IS_ERR(bmp_page)) {
1278        ntfs_error(sb, "Reading index bitmap failed.");
1279        err = PTR_ERR(bmp_page);
1280        bmp_page = NULL;
1281        goto iput_err_out;
1282    }
1283    bmp = (u8*)page_address(bmp_page);
1284    /* Find next index block in use. */
1285    while (!(bmp[cur_bmp_pos >> 3] & (1 << (cur_bmp_pos & 7)))) {
1286find_next_index_buffer:
1287        cur_bmp_pos++;
1288        /*
1289         * If we have reached the end of the bitmap page, get the next
1290         * page, and put away the old one.
1291         */
1292        if (unlikely((cur_bmp_pos >> 3) >= PAGE_CACHE_SIZE)) {
1293            ntfs_unmap_page(bmp_page);
1294            bmp_pos += PAGE_CACHE_SIZE * 8;
1295            cur_bmp_pos = 0;
1296            goto get_next_bmp_page;
1297        }
1298        /* If we have reached the end of the bitmap, we are done. */
1299        if (unlikely(((bmp_pos + cur_bmp_pos) >> 3) >= i_size))
1300            goto unm_EOD;
1301        ia_pos = (bmp_pos + cur_bmp_pos) <<
1302                ndir->itype.index.block_size_bits;
1303    }
1304    ntfs_debug("Handling index buffer 0x%llx.",
1305            (unsigned long long)bmp_pos + cur_bmp_pos);
1306    /* If the current index buffer is in the same page we reuse the page. */
1307    if ((prev_ia_pos & (s64)PAGE_CACHE_MASK) !=
1308            (ia_pos & (s64)PAGE_CACHE_MASK)) {
1309        prev_ia_pos = ia_pos;
1310        if (likely(ia_page != NULL)) {
1311            unlock_page(ia_page);
1312            ntfs_unmap_page(ia_page);
1313        }
1314        /*
1315         * Map the page cache page containing the current ia_pos,
1316         * reading it from disk if necessary.
1317         */
1318        ia_page = ntfs_map_page(ia_mapping, ia_pos >> PAGE_CACHE_SHIFT);
1319        if (IS_ERR(ia_page)) {
1320            ntfs_error(sb, "Reading index allocation data failed.");
1321            err = PTR_ERR(ia_page);
1322            ia_page = NULL;
1323            goto err_out;
1324        }
1325        lock_page(ia_page);
1326        kaddr = (u8*)page_address(ia_page);
1327    }
1328    /* Get the current index buffer. */
1329    ia = (INDEX_ALLOCATION*)(kaddr + (ia_pos & ~PAGE_CACHE_MASK &
1330            ~(s64)(ndir->itype.index.block_size - 1)));
1331    /* Bounds checks. */
1332    if (unlikely((u8*)ia < kaddr || (u8*)ia > kaddr + PAGE_CACHE_SIZE)) {
1333        ntfs_error(sb, "Out of bounds check failed. Corrupt directory "
1334                "inode 0x%lx or driver bug.", vdir->i_ino);
1335        goto err_out;
1336    }
1337    /* Catch multi sector transfer fixup errors. */
1338    if (unlikely(!ntfs_is_indx_record(ia->magic))) {
1339        ntfs_error(sb, "Directory index record with vcn 0x%llx is "
1340                "corrupt. Corrupt inode 0x%lx. Run chkdsk.",
1341                (unsigned long long)ia_pos >>
1342                ndir->itype.index.vcn_size_bits, vdir->i_ino);
1343        goto err_out;
1344    }
1345    if (unlikely(sle64_to_cpu(ia->index_block_vcn) != (ia_pos &
1346            ~(s64)(ndir->itype.index.block_size - 1)) >>
1347            ndir->itype.index.vcn_size_bits)) {
1348        ntfs_error(sb, "Actual VCN (0x%llx) of index buffer is "
1349                "different from expected VCN (0x%llx). "
1350                "Directory inode 0x%lx is corrupt or driver "
1351                "bug. ", (unsigned long long)
1352                sle64_to_cpu(ia->index_block_vcn),
1353                (unsigned long long)ia_pos >>
1354                ndir->itype.index.vcn_size_bits, vdir->i_ino);
1355        goto err_out;
1356    }
1357    if (unlikely(le32_to_cpu(ia->index.allocated_size) + 0x18 !=
1358            ndir->itype.index.block_size)) {
1359        ntfs_error(sb, "Index buffer (VCN 0x%llx) of directory inode "
1360                "0x%lx has a size (%u) differing from the "
1361                "directory specified size (%u). Directory "
1362                "inode is corrupt or driver bug.",
1363                (unsigned long long)ia_pos >>
1364                ndir->itype.index.vcn_size_bits, vdir->i_ino,
1365                le32_to_cpu(ia->index.allocated_size) + 0x18,
1366                ndir->itype.index.block_size);
1367        goto err_out;
1368    }
1369    index_end = (u8*)ia + ndir->itype.index.block_size;
1370    if (unlikely(index_end > kaddr + PAGE_CACHE_SIZE)) {
1371        ntfs_error(sb, "Index buffer (VCN 0x%llx) of directory inode "
1372                "0x%lx crosses page boundary. Impossible! "
1373                "Cannot access! This is probably a bug in the "
1374                "driver.", (unsigned long long)ia_pos >>
1375                ndir->itype.index.vcn_size_bits, vdir->i_ino);
1376        goto err_out;
1377    }
1378    ia_start = ia_pos & ~(s64)(ndir->itype.index.block_size - 1);
1379    index_end = (u8*)&ia->index + le32_to_cpu(ia->index.index_length);
1380    if (unlikely(index_end > (u8*)ia + ndir->itype.index.block_size)) {
1381        ntfs_error(sb, "Size of index buffer (VCN 0x%llx) of directory "
1382                "inode 0x%lx exceeds maximum size.",
1383                (unsigned long long)ia_pos >>
1384                ndir->itype.index.vcn_size_bits, vdir->i_ino);
1385        goto err_out;
1386    }
1387    /* The first index entry in this index buffer. */
1388    ie = (INDEX_ENTRY*)((u8*)&ia->index +
1389            le32_to_cpu(ia->index.entries_offset));
1390    /*
1391     * Loop until we exceed valid memory (corruption case) or until we
1392     * reach the last entry or until filldir tells us it has had enough
1393     * or signals an error (both covered by the rc test).
1394     */
1395    for (;; ie = (INDEX_ENTRY*)((u8*)ie + le16_to_cpu(ie->length))) {
1396        ntfs_debug("In index allocation, offset 0x%llx.",
1397                (unsigned long long)ia_start +
1398                (unsigned long long)((u8*)ie - (u8*)ia));
1399        /* Bounds checks. */
1400        if (unlikely((u8*)ie < (u8*)ia || (u8*)ie +
1401                sizeof(INDEX_ENTRY_HEADER) > index_end ||
1402                (u8*)ie + le16_to_cpu(ie->key_length) >
1403                index_end))
1404            goto err_out;
1405        /* The last entry cannot contain a name. */
1406        if (ie->flags & INDEX_ENTRY_END)
1407            break;
1408        /* Skip index block entry if continuing previous readdir. */
1409        if (ia_pos - ia_start > (u8*)ie - (u8*)ia)
1410            continue;
1411        /* Advance the position even if going to skip the entry. */
1412        fpos = (u8*)ie - (u8*)ia +
1413                (sle64_to_cpu(ia->index_block_vcn) <<
1414                ndir->itype.index.vcn_size_bits) +
1415                vol->mft_record_size;
1416        /*
1417         * Submit the name to the @filldir callback. Note,
1418         * ntfs_filldir() drops the lock on @ia_page but it retakes it
1419         * before returning, unless a non-zero value is returned in
1420         * which case the page is left unlocked.
1421         */
1422        rc = ntfs_filldir(vol, fpos, ndir, ia_page, ie, name, dirent,
1423                filldir);
1424        if (rc) {
1425            /* @ia_page is already unlocked in this case. */
1426            ntfs_unmap_page(ia_page);
1427            ntfs_unmap_page(bmp_page);
1428            iput(bmp_vi);
1429            goto abort;
1430        }
1431    }
1432    goto find_next_index_buffer;
1433unm_EOD:
1434    if (ia_page) {
1435        unlock_page(ia_page);
1436        ntfs_unmap_page(ia_page);
1437    }
1438    ntfs_unmap_page(bmp_page);
1439    iput(bmp_vi);
1440EOD:
1441    /* We are finished, set fpos to EOD. */
1442    fpos = i_size + vol->mft_record_size;
1443abort:
1444    kfree(name);
1445done:
1446#ifdef DEBUG
1447    if (!rc)
1448        ntfs_debug("EOD, fpos 0x%llx, returning 0.", fpos);
1449    else
1450        ntfs_debug("filldir returned %i, fpos 0x%llx, returning 0.",
1451                rc, fpos);
1452#endif
1453    filp->f_pos = fpos;
1454    return 0;
1455err_out:
1456    if (bmp_page) {
1457        ntfs_unmap_page(bmp_page);
1458iput_err_out:
1459        iput(bmp_vi);
1460    }
1461    if (ia_page) {
1462        unlock_page(ia_page);
1463        ntfs_unmap_page(ia_page);
1464    }
1465    kfree(ir);
1466    kfree(name);
1467    if (ctx)
1468        ntfs_attr_put_search_ctx(ctx);
1469    if (m)
1470        unmap_mft_record(ndir);
1471    if (!err)
1472        err = -EIO;
1473    ntfs_debug("Failed. Returning error code %i.", -err);
1474    filp->f_pos = fpos;
1475    return err;
1476}
1477
1478/**
1479 * ntfs_dir_open - called when an inode is about to be opened
1480 * @vi: inode to be opened
1481 * @filp: file structure describing the inode
1482 *
1483 * Limit directory size to the page cache limit on architectures where unsigned
1484 * long is 32-bits. This is the most we can do for now without overflowing the
1485 * page cache page index. Doing it this way means we don't run into problems
1486 * because of existing too large directories. It would be better to allow the
1487 * user to read the accessible part of the directory but I doubt very much
1488 * anyone is going to hit this check on a 32-bit architecture, so there is no
1489 * point in adding the extra complexity required to support this.
1490 *
1491 * On 64-bit architectures, the check is hopefully optimized away by the
1492 * compiler.
1493 */
1494static int ntfs_dir_open(struct inode *vi, struct file *filp)
1495{
1496    if (sizeof(unsigned long) < 8) {
1497        if (i_size_read(vi) > MAX_LFS_FILESIZE)
1498            return -EFBIG;
1499    }
1500    return 0;
1501}
1502
1503#ifdef NTFS_RW
1504
1505/**
1506 * ntfs_dir_fsync - sync a directory to disk
1507 * @filp: directory to be synced
1508 * @dentry: dentry describing the directory to sync
1509 * @datasync: if non-zero only flush user data and not metadata
1510 *
1511 * Data integrity sync of a directory to disk. Used for fsync, fdatasync, and
1512 * msync system calls. This function is based on file.c::ntfs_file_fsync().
1513 *
1514 * Write the mft record and all associated extent mft records as well as the
1515 * $INDEX_ALLOCATION and $BITMAP attributes and then sync the block device.
1516 *
1517 * If @datasync is true, we do not wait on the inode(s) to be written out
1518 * but we always wait on the page cache pages to be written out.
1519 *
1520 * Note: In the past @filp could be NULL so we ignore it as we don't need it
1521 * anyway.
1522 *
1523 * Locking: Caller must hold i_mutex on the inode.
1524 *
1525 * TODO: We should probably also write all attribute/index inodes associated
1526 * with this inode but since we have no simple way of getting to them we ignore
1527 * this problem for now. We do write the $BITMAP attribute if it is present
1528 * which is the important one for a directory so things are not too bad.
1529 */
1530static int ntfs_dir_fsync(struct file *filp, int datasync)
1531{
1532    struct inode *bmp_vi, *vi = filp->f_mapping->host;
1533    int err, ret;
1534    ntfs_attr na;
1535
1536    ntfs_debug("Entering for inode 0x%lx.", vi->i_ino);
1537    BUG_ON(!S_ISDIR(vi->i_mode));
1538    /* If the bitmap attribute inode is in memory sync it, too. */
1539    na.mft_no = vi->i_ino;
1540    na.type = AT_BITMAP;
1541    na.name = I30;
1542    na.name_len = 4;
1543    bmp_vi = ilookup5(vi->i_sb, vi->i_ino, (test_t)ntfs_test_inode, &na);
1544    if (bmp_vi) {
1545         write_inode_now(bmp_vi, !datasync);
1546        iput(bmp_vi);
1547    }
1548    ret = __ntfs_write_inode(vi, 1);
1549    write_inode_now(vi, !datasync);
1550    err = sync_blockdev(vi->i_sb->s_bdev);
1551    if (unlikely(err && !ret))
1552        ret = err;
1553    if (likely(!ret))
1554        ntfs_debug("Done.");
1555    else
1556        ntfs_warning(vi->i_sb, "Failed to f%ssync inode 0x%lx. Error "
1557                "%u.", datasync ? "data" : "", vi->i_ino, -ret);
1558    return ret;
1559}
1560
1561#endif /* NTFS_RW */
1562
1563const struct file_operations ntfs_dir_ops = {
1564    .llseek = generic_file_llseek, /* Seek inside directory. */
1565    .read = generic_read_dir, /* Return -EISDIR. */
1566    .readdir = ntfs_readdir, /* Read directory contents. */
1567#ifdef NTFS_RW
1568    .fsync = ntfs_dir_fsync, /* Sync a directory to disk. */
1569    /*.aio_fsync = ,*/ /* Sync all outstanding async
1570                           i/o operations on a kiocb. */
1571#endif /* NTFS_RW */
1572    /*.ioctl = ,*/ /* Perform function on the
1573                           mounted filesystem. */
1574    .open = ntfs_dir_open, /* Open directory. */
1575};
1576

Archive Download this file



interactive