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TOMOYO Linux Cross Reference
Linux/fs/jffs2/readinode.c

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  1 /*
  2  * JFFS2 -- Journalling Flash File System, Version 2.
  3  *
  4  * Copyright © 2001-2007 Red Hat, Inc.
  5  *
  6  * Created by David Woodhouse <dwmw2@infradead.org>
  7  *
  8  * For licensing information, see the file 'LICENCE' in this directory.
  9  *
 10  */
 11 
 12 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 13 
 14 #include <linux/kernel.h>
 15 #include <linux/sched.h>
 16 #include <linux/slab.h>
 17 #include <linux/fs.h>
 18 #include <linux/crc32.h>
 19 #include <linux/pagemap.h>
 20 #include <linux/mtd/mtd.h>
 21 #include <linux/compiler.h>
 22 #include "nodelist.h"
 23 
 24 /*
 25  * Check the data CRC of the node.
 26  *
 27  * Returns: 0 if the data CRC is correct;
 28  *          1 - if incorrect;
 29  *          error code if an error occurred.
 30  */
 31 static int check_node_data(struct jffs2_sb_info *c, struct jffs2_tmp_dnode_info *tn)
 32 {
 33         struct jffs2_raw_node_ref *ref = tn->fn->raw;
 34         int err = 0, pointed = 0;
 35         struct jffs2_eraseblock *jeb;
 36         unsigned char *buffer;
 37         uint32_t crc, ofs, len;
 38         size_t retlen;
 39 
 40         BUG_ON(tn->csize == 0);
 41 
 42         /* Calculate how many bytes were already checked */
 43         ofs = ref_offset(ref) + sizeof(struct jffs2_raw_inode);
 44         len = tn->csize;
 45 
 46         if (jffs2_is_writebuffered(c)) {
 47                 int adj = ofs % c->wbuf_pagesize;
 48                 if (likely(adj))
 49                         adj = c->wbuf_pagesize - adj;
 50 
 51                 if (adj >= tn->csize) {
 52                         dbg_readinode("no need to check node at %#08x, data length %u, data starts at %#08x - it has already been checked.\n",
 53                                       ref_offset(ref), tn->csize, ofs);
 54                         goto adj_acc;
 55                 }
 56 
 57                 ofs += adj;
 58                 len -= adj;
 59         }
 60 
 61         dbg_readinode("check node at %#08x, data length %u, partial CRC %#08x, correct CRC %#08x, data starts at %#08x, start checking from %#08x - %u bytes.\n",
 62                 ref_offset(ref), tn->csize, tn->partial_crc, tn->data_crc, ofs - len, ofs, len);
 63 
 64 #ifndef __ECOS
 65         /* TODO: instead, incapsulate point() stuff to jffs2_flash_read(),
 66          * adding and jffs2_flash_read_end() interface. */
 67         err = mtd_point(c->mtd, ofs, len, &retlen, (void **)&buffer, NULL);
 68         if (!err && retlen < len) {
 69                 JFFS2_WARNING("MTD point returned len too short: %zu instead of %u.\n", retlen, tn->csize);
 70                 mtd_unpoint(c->mtd, ofs, retlen);
 71         } else if (err) {
 72                 if (err != -EOPNOTSUPP)
 73                         JFFS2_WARNING("MTD point failed: error code %d.\n", err);
 74         } else
 75                 pointed = 1; /* succefully pointed to device */
 76 #endif
 77 
 78         if (!pointed) {
 79                 buffer = kmalloc(len, GFP_KERNEL);
 80                 if (unlikely(!buffer))
 81                         return -ENOMEM;
 82 
 83                 /* TODO: this is very frequent pattern, make it a separate
 84                  * routine */
 85                 err = jffs2_flash_read(c, ofs, len, &retlen, buffer);
 86                 if (err) {
 87                         JFFS2_ERROR("can not read %d bytes from 0x%08x, error code: %d.\n", len, ofs, err);
 88                         goto free_out;
 89                 }
 90 
 91                 if (retlen != len) {
 92                         JFFS2_ERROR("short read at %#08x: %zd instead of %d.\n", ofs, retlen, len);
 93                         err = -EIO;
 94                         goto free_out;
 95                 }
 96         }
 97 
 98         /* Continue calculating CRC */
 99         crc = crc32(tn->partial_crc, buffer, len);
100         if(!pointed)
101                 kfree(buffer);
102 #ifndef __ECOS
103         else
104                 mtd_unpoint(c->mtd, ofs, len);
105 #endif
106 
107         if (crc != tn->data_crc) {
108                 JFFS2_NOTICE("wrong data CRC in data node at 0x%08x: read %#08x, calculated %#08x.\n",
109                              ref_offset(ref), tn->data_crc, crc);
110                 return 1;
111         }
112 
113 adj_acc:
114         jeb = &c->blocks[ref->flash_offset / c->sector_size];
115         len = ref_totlen(c, jeb, ref);
116         /* If it should be REF_NORMAL, it'll get marked as such when
117            we build the fragtree, shortly. No need to worry about GC
118            moving it while it's marked REF_PRISTINE -- GC won't happen
119            till we've finished checking every inode anyway. */
120         ref->flash_offset |= REF_PRISTINE;
121         /*
122          * Mark the node as having been checked and fix the
123          * accounting accordingly.
124          */
125         spin_lock(&c->erase_completion_lock);
126         jeb->used_size += len;
127         jeb->unchecked_size -= len;
128         c->used_size += len;
129         c->unchecked_size -= len;
130         jffs2_dbg_acct_paranoia_check_nolock(c, jeb);
131         spin_unlock(&c->erase_completion_lock);
132 
133         return 0;
134 
135 free_out:
136         if(!pointed)
137                 kfree(buffer);
138 #ifndef __ECOS
139         else
140                 mtd_unpoint(c->mtd, ofs, len);
141 #endif
142         return err;
143 }
144 
145 /*
146  * Helper function for jffs2_add_older_frag_to_fragtree().
147  *
148  * Checks the node if we are in the checking stage.
149  */
150 static int check_tn_node(struct jffs2_sb_info *c, struct jffs2_tmp_dnode_info *tn)
151 {
152         int ret;
153 
154         BUG_ON(ref_obsolete(tn->fn->raw));
155 
156         /* We only check the data CRC of unchecked nodes */
157         if (ref_flags(tn->fn->raw) != REF_UNCHECKED)
158                 return 0;
159 
160         dbg_readinode("check node %#04x-%#04x, phys offs %#08x\n",
161                       tn->fn->ofs, tn->fn->ofs + tn->fn->size, ref_offset(tn->fn->raw));
162 
163         ret = check_node_data(c, tn);
164         if (unlikely(ret < 0)) {
165                 JFFS2_ERROR("check_node_data() returned error: %d.\n",
166                         ret);
167         } else if (unlikely(ret > 0)) {
168                 dbg_readinode("CRC error, mark it obsolete.\n");
169                 jffs2_mark_node_obsolete(c, tn->fn->raw);
170         }
171 
172         return ret;
173 }
174 
175 static struct jffs2_tmp_dnode_info *jffs2_lookup_tn(struct rb_root *tn_root, uint32_t offset)
176 {
177         struct rb_node *next;
178         struct jffs2_tmp_dnode_info *tn = NULL;
179 
180         dbg_readinode("root %p, offset %d\n", tn_root, offset);
181 
182         next = tn_root->rb_node;
183 
184         while (next) {
185                 tn = rb_entry(next, struct jffs2_tmp_dnode_info, rb);
186 
187                 if (tn->fn->ofs < offset)
188                         next = tn->rb.rb_right;
189                 else if (tn->fn->ofs >= offset)
190                         next = tn->rb.rb_left;
191                 else
192                         break;
193         }
194 
195         return tn;
196 }
197 
198 
199 static void jffs2_kill_tn(struct jffs2_sb_info *c, struct jffs2_tmp_dnode_info *tn)
200 {
201         jffs2_mark_node_obsolete(c, tn->fn->raw);
202         jffs2_free_full_dnode(tn->fn);
203         jffs2_free_tmp_dnode_info(tn);
204 }
205 /*
206  * This function is used when we read an inode. Data nodes arrive in
207  * arbitrary order -- they may be older or newer than the nodes which
208  * are already in the tree. Where overlaps occur, the older node can
209  * be discarded as long as the newer passes the CRC check. We don't
210  * bother to keep track of holes in this rbtree, and neither do we deal
211  * with frags -- we can have multiple entries starting at the same
212  * offset, and the one with the smallest length will come first in the
213  * ordering.
214  *
215  * Returns 0 if the node was handled (including marking it obsolete)
216  *       < 0 an if error occurred
217  */
218 static int jffs2_add_tn_to_tree(struct jffs2_sb_info *c,
219                                 struct jffs2_readinode_info *rii,
220                                 struct jffs2_tmp_dnode_info *tn)
221 {
222         uint32_t fn_end = tn->fn->ofs + tn->fn->size;
223         struct jffs2_tmp_dnode_info *this, *ptn;
224 
225         dbg_readinode("insert fragment %#04x-%#04x, ver %u at %08x\n", tn->fn->ofs, fn_end, tn->version, ref_offset(tn->fn->raw));
226 
227         /* If a node has zero dsize, we only have to keep it if it might be the
228            node with highest version -- i.e. the one which will end up as f->metadata.
229            Note that such nodes won't be REF_UNCHECKED since there are no data to
230            check anyway. */
231         if (!tn->fn->size) {
232                 if (rii->mdata_tn) {
233                         if (rii->mdata_tn->version < tn->version) {
234                                 /* We had a candidate mdata node already */
235                                 dbg_readinode("kill old mdata with ver %d\n", rii->mdata_tn->version);
236                                 jffs2_kill_tn(c, rii->mdata_tn);
237                         } else {
238                                 dbg_readinode("kill new mdata with ver %d (older than existing %d\n",
239                                               tn->version, rii->mdata_tn->version);
240                                 jffs2_kill_tn(c, tn);
241                                 return 0;
242                         }
243                 }
244                 rii->mdata_tn = tn;
245                 dbg_readinode("keep new mdata with ver %d\n", tn->version);
246                 return 0;
247         }
248 
249         /* Find the earliest node which _may_ be relevant to this one */
250         this = jffs2_lookup_tn(&rii->tn_root, tn->fn->ofs);
251         if (this) {
252                 /* If the node is coincident with another at a lower address,
253                    back up until the other node is found. It may be relevant */
254                 while (this->overlapped) {
255                         ptn = tn_prev(this);
256                         if (!ptn) {
257                                 /*
258                                  * We killed a node which set the overlapped
259                                  * flags during the scan. Fix it up.
260                                  */
261                                 this->overlapped = 0;
262                                 break;
263                         }
264                         this = ptn;
265                 }
266                 dbg_readinode("'this' found %#04x-%#04x (%s)\n", this->fn->ofs, this->fn->ofs + this->fn->size, this->fn ? "data" : "hole");
267         }
268 
269         while (this) {
270                 if (this->fn->ofs > fn_end)
271                         break;
272                 dbg_readinode("Ponder this ver %d, 0x%x-0x%x\n",
273                               this->version, this->fn->ofs, this->fn->size);
274 
275                 if (this->version == tn->version) {
276                         /* Version number collision means REF_PRISTINE GC. Accept either of them
277                            as long as the CRC is correct. Check the one we have already...  */
278                         if (!check_tn_node(c, this)) {
279                                 /* The one we already had was OK. Keep it and throw away the new one */
280                                 dbg_readinode("Like old node. Throw away new\n");
281                                 jffs2_kill_tn(c, tn);
282                                 return 0;
283                         } else {
284                                 /* Who cares if the new one is good; keep it for now anyway. */
285                                 dbg_readinode("Like new node. Throw away old\n");
286                                 rb_replace_node(&this->rb, &tn->rb, &rii->tn_root);
287                                 jffs2_kill_tn(c, this);
288                                 /* Same overlapping from in front and behind */
289                                 return 0;
290                         }
291                 }
292                 if (this->version < tn->version &&
293                     this->fn->ofs >= tn->fn->ofs &&
294                     this->fn->ofs + this->fn->size <= fn_end) {
295                         /* New node entirely overlaps 'this' */
296                         if (check_tn_node(c, tn)) {
297                                 dbg_readinode("new node bad CRC\n");
298                                 jffs2_kill_tn(c, tn);
299                                 return 0;
300                         }
301                         /* ... and is good. Kill 'this' and any subsequent nodes which are also overlapped */
302                         while (this && this->fn->ofs + this->fn->size <= fn_end) {
303                                 struct jffs2_tmp_dnode_info *next = tn_next(this);
304                                 if (this->version < tn->version) {
305                                         tn_erase(this, &rii->tn_root);
306                                         dbg_readinode("Kill overlapped ver %d, 0x%x-0x%x\n",
307                                                       this->version, this->fn->ofs,
308                                                       this->fn->ofs+this->fn->size);
309                                         jffs2_kill_tn(c, this);
310                                 }
311                                 this = next;
312                         }
313                         dbg_readinode("Done killing overlapped nodes\n");
314                         continue;
315                 }
316                 if (this->version > tn->version &&
317                     this->fn->ofs <= tn->fn->ofs &&
318                     this->fn->ofs+this->fn->size >= fn_end) {
319                         /* New node entirely overlapped by 'this' */
320                         if (!check_tn_node(c, this)) {
321                                 dbg_readinode("Good CRC on old node. Kill new\n");
322                                 jffs2_kill_tn(c, tn);
323                                 return 0;
324                         }
325                         /* ... but 'this' was bad. Replace it... */
326                         dbg_readinode("Bad CRC on old overlapping node. Kill it\n");
327                         tn_erase(this, &rii->tn_root);
328                         jffs2_kill_tn(c, this);
329                         break;
330                 }
331 
332                 this = tn_next(this);
333         }
334 
335         /* We neither completely obsoleted nor were completely
336            obsoleted by an earlier node. Insert into the tree */
337         {
338                 struct rb_node *parent;
339                 struct rb_node **link = &rii->tn_root.rb_node;
340                 struct jffs2_tmp_dnode_info *insert_point = NULL;
341 
342                 while (*link) {
343                         parent = *link;
344                         insert_point = rb_entry(parent, struct jffs2_tmp_dnode_info, rb);
345                         if (tn->fn->ofs > insert_point->fn->ofs)
346                                 link = &insert_point->rb.rb_right;
347                         else if (tn->fn->ofs < insert_point->fn->ofs ||
348                                  tn->fn->size < insert_point->fn->size)
349                                 link = &insert_point->rb.rb_left;
350                         else
351                                 link = &insert_point->rb.rb_right;
352                 }
353                 rb_link_node(&tn->rb, &insert_point->rb, link);
354                 rb_insert_color(&tn->rb, &rii->tn_root);
355         }
356 
357         /* If there's anything behind that overlaps us, note it */
358         this = tn_prev(tn);
359         if (this) {
360                 while (1) {
361                         if (this->fn->ofs + this->fn->size > tn->fn->ofs) {
362                                 dbg_readinode("Node is overlapped by %p (v %d, 0x%x-0x%x)\n",
363                                               this, this->version, this->fn->ofs,
364                                               this->fn->ofs+this->fn->size);
365                                 tn->overlapped = 1;
366                                 break;
367                         }
368                         if (!this->overlapped)
369                                 break;
370 
371                         ptn = tn_prev(this);
372                         if (!ptn) {
373                                 /*
374                                  * We killed a node which set the overlapped
375                                  * flags during the scan. Fix it up.
376                                  */
377                                 this->overlapped = 0;
378                                 break;
379                         }
380                         this = ptn;
381                 }
382         }
383 
384         /* If the new node overlaps anything ahead, note it */
385         this = tn_next(tn);
386         while (this && this->fn->ofs < fn_end) {
387                 this->overlapped = 1;
388                 dbg_readinode("Node ver %d, 0x%x-0x%x is overlapped\n",
389                               this->version, this->fn->ofs,
390                               this->fn->ofs+this->fn->size);
391                 this = tn_next(this);
392         }
393         return 0;
394 }
395 
396 /* Trivial function to remove the last node in the tree. Which by definition
397    has no right-hand child — so can be removed just by making its left-hand
398    child (if any) take its place under its parent. Since this is only done
399    when we're consuming the whole tree, there's no need to use rb_erase()
400    and let it worry about adjusting colours and balancing the tree. That
401    would just be a waste of time. */
402 static void eat_last(struct rb_root *root, struct rb_node *node)
403 {
404         struct rb_node *parent = rb_parent(node);
405         struct rb_node **link;
406 
407         /* LAST! */
408         BUG_ON(node->rb_right);
409 
410         if (!parent)
411                 link = &root->rb_node;
412         else if (node == parent->rb_left)
413                 link = &parent->rb_left;
414         else
415                 link = &parent->rb_right;
416 
417         *link = node->rb_left;
418         if (node->rb_left)
419                 node->rb_left->__rb_parent_color = node->__rb_parent_color;
420 }
421 
422 /* We put the version tree in reverse order, so we can use the same eat_last()
423    function that we use to consume the tmpnode tree (tn_root). */
424 static void ver_insert(struct rb_root *ver_root, struct jffs2_tmp_dnode_info *tn)
425 {
426         struct rb_node **link = &ver_root->rb_node;
427         struct rb_node *parent = NULL;
428         struct jffs2_tmp_dnode_info *this_tn;
429 
430         while (*link) {
431                 parent = *link;
432                 this_tn = rb_entry(parent, struct jffs2_tmp_dnode_info, rb);
433 
434                 if (tn->version > this_tn->version)
435                         link = &parent->rb_left;
436                 else
437                         link = &parent->rb_right;
438         }
439         dbg_readinode("Link new node at %p (root is %p)\n", link, ver_root);
440         rb_link_node(&tn->rb, parent, link);
441         rb_insert_color(&tn->rb, ver_root);
442 }
443 
444 /* Build final, normal fragtree from tn tree. It doesn't matter which order
445    we add nodes to the real fragtree, as long as they don't overlap. And
446    having thrown away the majority of overlapped nodes as we went, there
447    really shouldn't be many sets of nodes which do overlap. If we start at
448    the end, we can use the overlap markers -- we can just eat nodes which
449    aren't overlapped, and when we encounter nodes which _do_ overlap we
450    sort them all into a temporary tree in version order before replaying them. */
451 static int jffs2_build_inode_fragtree(struct jffs2_sb_info *c,
452                                       struct jffs2_inode_info *f,
453                                       struct jffs2_readinode_info *rii)
454 {
455         struct jffs2_tmp_dnode_info *pen, *last, *this;
456         struct rb_root ver_root = RB_ROOT;
457         uint32_t high_ver = 0;
458 
459         if (rii->mdata_tn) {
460                 dbg_readinode("potential mdata is ver %d at %p\n", rii->mdata_tn->version, rii->mdata_tn);
461                 high_ver = rii->mdata_tn->version;
462                 rii->latest_ref = rii->mdata_tn->fn->raw;
463         }
464 #ifdef JFFS2_DBG_READINODE_MESSAGES
465         this = tn_last(&rii->tn_root);
466         while (this) {
467                 dbg_readinode("tn %p ver %d range 0x%x-0x%x ov %d\n", this, this->version, this->fn->ofs,
468                               this->fn->ofs+this->fn->size, this->overlapped);
469                 this = tn_prev(this);
470         }
471 #endif
472         pen = tn_last(&rii->tn_root);
473         while ((last = pen)) {
474                 pen = tn_prev(last);
475 
476                 eat_last(&rii->tn_root, &last->rb);
477                 ver_insert(&ver_root, last);
478 
479                 if (unlikely(last->overlapped)) {
480                         if (pen)
481                                 continue;
482                         /*
483                          * We killed a node which set the overlapped
484                          * flags during the scan. Fix it up.
485                          */
486                         last->overlapped = 0;
487                 }
488 
489                 /* Now we have a bunch of nodes in reverse version
490                    order, in the tree at ver_root. Most of the time,
491                    there'll actually be only one node in the 'tree',
492                    in fact. */
493                 this = tn_last(&ver_root);
494 
495                 while (this) {
496                         struct jffs2_tmp_dnode_info *vers_next;
497                         int ret;
498                         vers_next = tn_prev(this);
499                         eat_last(&ver_root, &this->rb);
500                         if (check_tn_node(c, this)) {
501                                 dbg_readinode("node ver %d, 0x%x-0x%x failed CRC\n",
502                                              this->version, this->fn->ofs,
503                                              this->fn->ofs+this->fn->size);
504                                 jffs2_kill_tn(c, this);
505                         } else {
506                                 if (this->version > high_ver) {
507                                         /* Note that this is different from the other
508                                            highest_version, because this one is only
509                                            counting _valid_ nodes which could give the
510                                            latest inode metadata */
511                                         high_ver = this->version;
512                                         rii->latest_ref = this->fn->raw;
513                                 }
514                                 dbg_readinode("Add %p (v %d, 0x%x-0x%x, ov %d) to fragtree\n",
515                                              this, this->version, this->fn->ofs,
516                                              this->fn->ofs+this->fn->size, this->overlapped);
517 
518                                 ret = jffs2_add_full_dnode_to_inode(c, f, this->fn);
519                                 if (ret) {
520                                         /* Free the nodes in vers_root; let the caller
521                                            deal with the rest */
522                                         JFFS2_ERROR("Add node to tree failed %d\n", ret);
523                                         while (1) {
524                                                 vers_next = tn_prev(this);
525                                                 if (check_tn_node(c, this))
526                                                         jffs2_mark_node_obsolete(c, this->fn->raw);
527                                                 jffs2_free_full_dnode(this->fn);
528                                                 jffs2_free_tmp_dnode_info(this);
529                                                 this = vers_next;
530                                                 if (!this)
531                                                         break;
532                                                 eat_last(&ver_root, &vers_next->rb);
533                                         }
534                                         return ret;
535                                 }
536                                 jffs2_free_tmp_dnode_info(this);
537                         }
538                         this = vers_next;
539                 }
540         }
541         return 0;
542 }
543 
544 static void jffs2_free_tmp_dnode_info_list(struct rb_root *list)
545 {
546         struct jffs2_tmp_dnode_info *tn, *next;
547 
548         rbtree_postorder_for_each_entry_safe(tn, next, list, rb) {
549                         jffs2_free_full_dnode(tn->fn);
550                         jffs2_free_tmp_dnode_info(tn);
551         }
552 
553         *list = RB_ROOT;
554 }
555 
556 static void jffs2_free_full_dirent_list(struct jffs2_full_dirent *fd)
557 {
558         struct jffs2_full_dirent *next;
559 
560         while (fd) {
561                 next = fd->next;
562                 jffs2_free_full_dirent(fd);
563                 fd = next;
564         }
565 }
566 
567 /* Returns first valid node after 'ref'. May return 'ref' */
568 static struct jffs2_raw_node_ref *jffs2_first_valid_node(struct jffs2_raw_node_ref *ref)
569 {
570         while (ref && ref->next_in_ino) {
571                 if (!ref_obsolete(ref))
572                         return ref;
573                 dbg_noderef("node at 0x%08x is obsoleted. Ignoring.\n", ref_offset(ref));
574                 ref = ref->next_in_ino;
575         }
576         return NULL;
577 }
578 
579 /*
580  * Helper function for jffs2_get_inode_nodes().
581  * It is called every time an directory entry node is found.
582  *
583  * Returns: 0 on success;
584  *          negative error code on failure.
585  */
586 static inline int read_direntry(struct jffs2_sb_info *c, struct jffs2_raw_node_ref *ref,
587                                 struct jffs2_raw_dirent *rd, size_t read,
588                                 struct jffs2_readinode_info *rii)
589 {
590         struct jffs2_full_dirent *fd;
591         uint32_t crc;
592 
593         /* Obsoleted. This cannot happen, surely? dwmw2 20020308 */
594         BUG_ON(ref_obsolete(ref));
595 
596         crc = crc32(0, rd, sizeof(*rd) - 8);
597         if (unlikely(crc != je32_to_cpu(rd->node_crc))) {
598                 JFFS2_NOTICE("header CRC failed on dirent node at %#08x: read %#08x, calculated %#08x\n",
599                              ref_offset(ref), je32_to_cpu(rd->node_crc), crc);
600                 jffs2_mark_node_obsolete(c, ref);
601                 return 0;
602         }
603 
604         /* If we've never checked the CRCs on this node, check them now */
605         if (ref_flags(ref) == REF_UNCHECKED) {
606                 struct jffs2_eraseblock *jeb;
607                 int len;
608 
609                 /* Sanity check */
610                 if (unlikely(PAD((rd->nsize + sizeof(*rd))) != PAD(je32_to_cpu(rd->totlen)))) {
611                         JFFS2_ERROR("illegal nsize in node at %#08x: nsize %#02x, totlen %#04x\n",
612                                     ref_offset(ref), rd->nsize, je32_to_cpu(rd->totlen));
613                         jffs2_mark_node_obsolete(c, ref);
614                         return 0;
615                 }
616 
617                 jeb = &c->blocks[ref->flash_offset / c->sector_size];
618                 len = ref_totlen(c, jeb, ref);
619 
620                 spin_lock(&c->erase_completion_lock);
621                 jeb->used_size += len;
622                 jeb->unchecked_size -= len;
623                 c->used_size += len;
624                 c->unchecked_size -= len;
625                 ref->flash_offset = ref_offset(ref) | dirent_node_state(rd);
626                 spin_unlock(&c->erase_completion_lock);
627         }
628 
629         fd = jffs2_alloc_full_dirent(rd->nsize + 1);
630         if (unlikely(!fd))
631                 return -ENOMEM;
632 
633         fd->raw = ref;
634         fd->version = je32_to_cpu(rd->version);
635         fd->ino = je32_to_cpu(rd->ino);
636         fd->type = rd->type;
637 
638         if (fd->version > rii->highest_version)
639                 rii->highest_version = fd->version;
640 
641         /* Pick out the mctime of the latest dirent */
642         if(fd->version > rii->mctime_ver && je32_to_cpu(rd->mctime)) {
643                 rii->mctime_ver = fd->version;
644                 rii->latest_mctime = je32_to_cpu(rd->mctime);
645         }
646 
647         /*
648          * Copy as much of the name as possible from the raw
649          * dirent we've already read from the flash.
650          */
651         if (read > sizeof(*rd))
652                 memcpy(&fd->name[0], &rd->name[0],
653                        min_t(uint32_t, rd->nsize, (read - sizeof(*rd)) ));
654 
655         /* Do we need to copy any more of the name directly from the flash? */
656         if (rd->nsize + sizeof(*rd) > read) {
657                 /* FIXME: point() */
658                 int err;
659                 int already = read - sizeof(*rd);
660 
661                 err = jffs2_flash_read(c, (ref_offset(ref)) + read,
662                                 rd->nsize - already, &read, &fd->name[already]);
663                 if (unlikely(read != rd->nsize - already) && likely(!err)) {
664                         jffs2_free_full_dirent(fd);
665                         JFFS2_ERROR("short read: wanted %d bytes, got %zd\n",
666                                     rd->nsize - already, read);
667                         return -EIO;
668                 }
669 
670                 if (unlikely(err)) {
671                         JFFS2_ERROR("read remainder of name: error %d\n", err);
672                         jffs2_free_full_dirent(fd);
673                         return -EIO;
674                 }
675         }
676 
677         fd->nhash = full_name_hash(NULL, fd->name, rd->nsize);
678         fd->next = NULL;
679         fd->name[rd->nsize] = '\0';
680 
681         /*
682          * Wheee. We now have a complete jffs2_full_dirent structure, with
683          * the name in it and everything. Link it into the list
684          */
685         jffs2_add_fd_to_list(c, fd, &rii->fds);
686 
687         return 0;
688 }
689 
690 /*
691  * Helper function for jffs2_get_inode_nodes().
692  * It is called every time an inode node is found.
693  *
694  * Returns: 0 on success (possibly after marking a bad node obsolete);
695  *          negative error code on failure.
696  */
697 static inline int read_dnode(struct jffs2_sb_info *c, struct jffs2_raw_node_ref *ref,
698                              struct jffs2_raw_inode *rd, int rdlen,
699                              struct jffs2_readinode_info *rii)
700 {
701         struct jffs2_tmp_dnode_info *tn;
702         uint32_t len, csize;
703         int ret = 0;
704         uint32_t crc;
705 
706         /* Obsoleted. This cannot happen, surely? dwmw2 20020308 */
707         BUG_ON(ref_obsolete(ref));
708 
709         crc = crc32(0, rd, sizeof(*rd) - 8);
710         if (unlikely(crc != je32_to_cpu(rd->node_crc))) {
711                 JFFS2_NOTICE("node CRC failed on dnode at %#08x: read %#08x, calculated %#08x\n",
712                              ref_offset(ref), je32_to_cpu(rd->node_crc), crc);
713                 jffs2_mark_node_obsolete(c, ref);
714                 return 0;
715         }
716 
717         tn = jffs2_alloc_tmp_dnode_info();
718         if (!tn) {
719                 JFFS2_ERROR("failed to allocate tn (%zu bytes).\n", sizeof(*tn));
720                 return -ENOMEM;
721         }
722 
723         tn->partial_crc = 0;
724         csize = je32_to_cpu(rd->csize);
725 
726         /* If we've never checked the CRCs on this node, check them now */
727         if (ref_flags(ref) == REF_UNCHECKED) {
728 
729                 /* Sanity checks */
730                 if (unlikely(je32_to_cpu(rd->offset) > je32_to_cpu(rd->isize)) ||
731                     unlikely(PAD(je32_to_cpu(rd->csize) + sizeof(*rd)) != PAD(je32_to_cpu(rd->totlen)))) {
732                         JFFS2_WARNING("inode node header CRC is corrupted at %#08x\n", ref_offset(ref));
733                         jffs2_dbg_dump_node(c, ref_offset(ref));
734                         jffs2_mark_node_obsolete(c, ref);
735                         goto free_out;
736                 }
737 
738                 if (jffs2_is_writebuffered(c) && csize != 0) {
739                         /* At this point we are supposed to check the data CRC
740                          * of our unchecked node. But thus far, we do not
741                          * know whether the node is valid or obsolete. To
742                          * figure this out, we need to walk all the nodes of
743                          * the inode and build the inode fragtree. We don't
744                          * want to spend time checking data of nodes which may
745                          * later be found to be obsolete. So we put off the full
746                          * data CRC checking until we have read all the inode
747                          * nodes and have started building the fragtree.
748                          *
749                          * The fragtree is being built starting with nodes
750                          * having the highest version number, so we'll be able
751                          * to detect whether a node is valid (i.e., it is not
752                          * overlapped by a node with higher version) or not.
753                          * And we'll be able to check only those nodes, which
754                          * are not obsolete.
755                          *
756                          * Of course, this optimization only makes sense in case
757                          * of NAND flashes (or other flashes with
758                          * !jffs2_can_mark_obsolete()), since on NOR flashes
759                          * nodes are marked obsolete physically.
760                          *
761                          * Since NAND flashes (or other flashes with
762                          * jffs2_is_writebuffered(c)) are anyway read by
763                          * fractions of c->wbuf_pagesize, and we have just read
764                          * the node header, it is likely that the starting part
765                          * of the node data is also read when we read the
766                          * header. So we don't mind to check the CRC of the
767                          * starting part of the data of the node now, and check
768                          * the second part later (in jffs2_check_node_data()).
769                          * Of course, we will not need to re-read and re-check
770                          * the NAND page which we have just read. This is why we
771                          * read the whole NAND page at jffs2_get_inode_nodes(),
772                          * while we needed only the node header.
773                          */
774                         unsigned char *buf;
775 
776                         /* 'buf' will point to the start of data */
777                         buf = (unsigned char *)rd + sizeof(*rd);
778                         /* len will be the read data length */
779                         len = min_t(uint32_t, rdlen - sizeof(*rd), csize);
780                         tn->partial_crc = crc32(0, buf, len);
781 
782                         dbg_readinode("Calculates CRC (%#08x) for %d bytes, csize %d\n", tn->partial_crc, len, csize);
783 
784                         /* If we actually calculated the whole data CRC
785                          * and it is wrong, drop the node. */
786                         if (len >= csize && unlikely(tn->partial_crc != je32_to_cpu(rd->data_crc))) {
787                                 JFFS2_NOTICE("wrong data CRC in data node at 0x%08x: read %#08x, calculated %#08x.\n",
788                                         ref_offset(ref), tn->partial_crc, je32_to_cpu(rd->data_crc));
789                                 jffs2_mark_node_obsolete(c, ref);
790                                 goto free_out;
791                         }
792 
793                 } else if (csize == 0) {
794                         /*
795                          * We checked the header CRC. If the node has no data, adjust
796                          * the space accounting now. For other nodes this will be done
797                          * later either when the node is marked obsolete or when its
798                          * data is checked.
799                          */
800                         struct jffs2_eraseblock *jeb;
801 
802                         dbg_readinode("the node has no data.\n");
803                         jeb = &c->blocks[ref->flash_offset / c->sector_size];
804                         len = ref_totlen(c, jeb, ref);
805 
806                         spin_lock(&c->erase_completion_lock);
807                         jeb->used_size += len;
808                         jeb->unchecked_size -= len;
809                         c->used_size += len;
810                         c->unchecked_size -= len;
811                         ref->flash_offset = ref_offset(ref) | REF_NORMAL;
812                         spin_unlock(&c->erase_completion_lock);
813                 }
814         }
815 
816         tn->fn = jffs2_alloc_full_dnode();
817         if (!tn->fn) {
818                 JFFS2_ERROR("alloc fn failed\n");
819                 ret = -ENOMEM;
820                 goto free_out;
821         }
822 
823         tn->version = je32_to_cpu(rd->version);
824         tn->fn->ofs = je32_to_cpu(rd->offset);
825         tn->data_crc = je32_to_cpu(rd->data_crc);
826         tn->csize = csize;
827         tn->fn->raw = ref;
828         tn->overlapped = 0;
829 
830         if (tn->version > rii->highest_version)
831                 rii->highest_version = tn->version;
832 
833         /* There was a bug where we wrote hole nodes out with
834            csize/dsize swapped. Deal with it */
835         if (rd->compr == JFFS2_COMPR_ZERO && !je32_to_cpu(rd->dsize) && csize)
836                 tn->fn->size = csize;
837         else // normal case...
838                 tn->fn->size = je32_to_cpu(rd->dsize);
839 
840         dbg_readinode2("dnode @%08x: ver %u, offset %#04x, dsize %#04x, csize %#04x\n",
841                        ref_offset(ref), je32_to_cpu(rd->version),
842                        je32_to_cpu(rd->offset), je32_to_cpu(rd->dsize), csize);
843 
844         ret = jffs2_add_tn_to_tree(c, rii, tn);
845 
846         if (ret) {
847                 jffs2_free_full_dnode(tn->fn);
848         free_out:
849                 jffs2_free_tmp_dnode_info(tn);
850                 return ret;
851         }
852 #ifdef JFFS2_DBG_READINODE2_MESSAGES
853         dbg_readinode2("After adding ver %d:\n", je32_to_cpu(rd->version));
854         tn = tn_first(&rii->tn_root);
855         while (tn) {
856                 dbg_readinode2("%p: v %d r 0x%x-0x%x ov %d\n",
857                                tn, tn->version, tn->fn->ofs,
858                                tn->fn->ofs+tn->fn->size, tn->overlapped);
859                 tn = tn_next(tn);
860         }
861 #endif
862         return 0;
863 }
864 
865 /*
866  * Helper function for jffs2_get_inode_nodes().
867  * It is called every time an unknown node is found.
868  *
869  * Returns: 0 on success;
870  *          negative error code on failure.
871  */
872 static inline int read_unknown(struct jffs2_sb_info *c, struct jffs2_raw_node_ref *ref, struct jffs2_unknown_node *un)
873 {
874         /* We don't mark unknown nodes as REF_UNCHECKED */
875         if (ref_flags(ref) == REF_UNCHECKED) {
876                 JFFS2_ERROR("REF_UNCHECKED but unknown node at %#08x\n",
877                             ref_offset(ref));
878                 JFFS2_ERROR("Node is {%04x,%04x,%08x,%08x}. Please report this error.\n",
879                             je16_to_cpu(un->magic), je16_to_cpu(un->nodetype),
880                             je32_to_cpu(un->totlen), je32_to_cpu(un->hdr_crc));
881                 jffs2_mark_node_obsolete(c, ref);
882                 return 0;
883         }
884 
885         un->nodetype = cpu_to_je16(JFFS2_NODE_ACCURATE | je16_to_cpu(un->nodetype));
886 
887         switch(je16_to_cpu(un->nodetype) & JFFS2_COMPAT_MASK) {
888 
889         case JFFS2_FEATURE_INCOMPAT:
890                 JFFS2_ERROR("unknown INCOMPAT nodetype %#04X at %#08x\n",
891                             je16_to_cpu(un->nodetype), ref_offset(ref));
892                 /* EEP */
893                 BUG();
894                 break;
895 
896         case JFFS2_FEATURE_ROCOMPAT:
897                 JFFS2_ERROR("unknown ROCOMPAT nodetype %#04X at %#08x\n",
898                             je16_to_cpu(un->nodetype), ref_offset(ref));
899                 BUG_ON(!(c->flags & JFFS2_SB_FLAG_RO));
900                 break;
901 
902         case JFFS2_FEATURE_RWCOMPAT_COPY:
903                 JFFS2_NOTICE("unknown RWCOMPAT_COPY nodetype %#04X at %#08x\n",
904                              je16_to_cpu(un->nodetype), ref_offset(ref));
905                 break;
906 
907         case JFFS2_FEATURE_RWCOMPAT_DELETE:
908                 JFFS2_NOTICE("unknown RWCOMPAT_DELETE nodetype %#04X at %#08x\n",
909                              je16_to_cpu(un->nodetype), ref_offset(ref));
910                 jffs2_mark_node_obsolete(c, ref);
911                 return 0;
912         }
913 
914         return 0;
915 }
916 
917 /*
918  * Helper function for jffs2_get_inode_nodes().
919  * The function detects whether more data should be read and reads it if yes.
920  *
921  * Returns: 0 on success;
922  *          negative error code on failure.
923  */
924 static int read_more(struct jffs2_sb_info *c, struct jffs2_raw_node_ref *ref,
925                      int needed_len, int *rdlen, unsigned char *buf)
926 {
927         int err, to_read = needed_len - *rdlen;
928         size_t retlen;
929         uint32_t offs;
930 
931         if (jffs2_is_writebuffered(c)) {
932                 int rem = to_read % c->wbuf_pagesize;
933 
934                 if (rem)
935                         to_read += c->wbuf_pagesize - rem;
936         }
937 
938         /* We need to read more data */
939         offs = ref_offset(ref) + *rdlen;
940 
941         dbg_readinode("read more %d bytes\n", to_read);
942 
943         err = jffs2_flash_read(c, offs, to_read, &retlen, buf + *rdlen);
944         if (err) {
945                 JFFS2_ERROR("can not read %d bytes from 0x%08x, "
946                         "error code: %d.\n", to_read, offs, err);
947                 return err;
948         }
949 
950         if (retlen < to_read) {
951                 JFFS2_ERROR("short read at %#08x: %zu instead of %d.\n",
952                                 offs, retlen, to_read);
953                 return -EIO;
954         }
955 
956         *rdlen += to_read;
957         return 0;
958 }
959 
960 /* Get tmp_dnode_info and full_dirent for all non-obsolete nodes associated
961    with this ino. Perform a preliminary ordering on data nodes, throwing away
962    those which are completely obsoleted by newer ones. The naïve approach we
963    use to take of just returning them _all_ in version order will cause us to
964    run out of memory in certain degenerate cases. */
965 static int jffs2_get_inode_nodes(struct jffs2_sb_info *c, struct jffs2_inode_info *f,
966                                  struct jffs2_readinode_info *rii)
967 {
968         struct jffs2_raw_node_ref *ref, *valid_ref;
969         unsigned char *buf = NULL;
970         union jffs2_node_union *node;
971         size_t retlen;
972         int len, err;
973 
974         rii->mctime_ver = 0;
975 
976         dbg_readinode("ino #%u\n", f->inocache->ino);
977 
978         /* FIXME: in case of NOR and available ->point() this
979          * needs to be fixed. */
980         len = sizeof(union jffs2_node_union) + c->wbuf_pagesize;
981         buf = kmalloc(len, GFP_KERNEL);
982         if (!buf)
983                 return -ENOMEM;
984 
985         spin_lock(&c->erase_completion_lock);
986         valid_ref = jffs2_first_valid_node(f->inocache->nodes);
987         if (!valid_ref && f->inocache->ino != 1)
988                 JFFS2_WARNING("Eep. No valid nodes for ino #%u.\n", f->inocache->ino);
989         while (valid_ref) {
990                 /* We can hold a pointer to a non-obsolete node without the spinlock,
991                    but _obsolete_ nodes may disappear at any time, if the block
992                    they're in gets erased. So if we mark 'ref' obsolete while we're
993                    not holding the lock, it can go away immediately. For that reason,
994                    we find the next valid node first, before processing 'ref'.
995                 */
996                 ref = valid_ref;
997                 valid_ref = jffs2_first_valid_node(ref->next_in_ino);
998                 spin_unlock(&c->erase_completion_lock);
999 
1000                 cond_resched();
1001 
1002                 /*
1003                  * At this point we don't know the type of the node we're going
1004                  * to read, so we do not know the size of its header. In order
1005                  * to minimize the amount of flash IO we assume the header is
1006                  * of size = JFFS2_MIN_NODE_HEADER.
1007                  */
1008                 len = JFFS2_MIN_NODE_HEADER;
1009                 if (jffs2_is_writebuffered(c)) {
1010                         int end, rem;
1011 
1012                         /*
1013                          * We are about to read JFFS2_MIN_NODE_HEADER bytes,
1014                          * but this flash has some minimal I/O unit. It is
1015                          * possible that we'll need to read more soon, so read
1016                          * up to the next min. I/O unit, in order not to
1017                          * re-read the same min. I/O unit twice.
1018                          */
1019                         end = ref_offset(ref) + len;
1020                         rem = end % c->wbuf_pagesize;
1021                         if (rem)
1022                                 end += c->wbuf_pagesize - rem;
1023                         len = end - ref_offset(ref);
1024                 }
1025 
1026                 dbg_readinode("read %d bytes at %#08x(%d).\n", len, ref_offset(ref), ref_flags(ref));
1027 
1028                 /* FIXME: point() */
1029                 err = jffs2_flash_read(c, ref_offset(ref), len, &retlen, buf);
1030                 if (err) {
1031                         JFFS2_ERROR("can not read %d bytes from 0x%08x, error code: %d.\n", len, ref_offset(ref), err);
1032                         goto free_out;
1033                 }
1034 
1035                 if (retlen < len) {
1036                         JFFS2_ERROR("short read at %#08x: %zu instead of %d.\n", ref_offset(ref), retlen, len);
1037                         err = -EIO;
1038                         goto free_out;
1039                 }
1040 
1041                 node = (union jffs2_node_union *)buf;
1042 
1043                 /* No need to mask in the valid bit; it shouldn't be invalid */
1044                 if (je32_to_cpu(node->u.hdr_crc) != crc32(0, node, sizeof(node->u)-4)) {
1045                         JFFS2_NOTICE("Node header CRC failed at %#08x. {%04x,%04x,%08x,%08x}\n",
1046                                      ref_offset(ref), je16_to_cpu(node->u.magic),
1047                                      je16_to_cpu(node->u.nodetype),
1048                                      je32_to_cpu(node->u.totlen),
1049                                      je32_to_cpu(node->u.hdr_crc));
1050                         jffs2_dbg_dump_node(c, ref_offset(ref));
1051                         jffs2_mark_node_obsolete(c, ref);
1052                         goto cont;
1053                 }
1054                 if (je16_to_cpu(node->u.magic) != JFFS2_MAGIC_BITMASK) {
1055                         /* Not a JFFS2 node, whinge and move on */
1056                         JFFS2_NOTICE("Wrong magic bitmask 0x%04x in node header at %#08x.\n",
1057                                      je16_to_cpu(node->u.magic), ref_offset(ref));
1058                         jffs2_mark_node_obsolete(c, ref);
1059                         goto cont;
1060                 }
1061 
1062                 switch (je16_to_cpu(node->u.nodetype)) {
1063 
1064                 case JFFS2_NODETYPE_DIRENT:
1065 
1066                         if (JFFS2_MIN_NODE_HEADER < sizeof(struct jffs2_raw_dirent) &&
1067                             len < sizeof(struct jffs2_raw_dirent)) {
1068                                 err = read_more(c, ref, sizeof(struct jffs2_raw_dirent), &len, buf);
1069                                 if (unlikely(err))
1070                                         goto free_out;
1071                         }
1072 
1073                         err = read_direntry(c, ref, &node->d, retlen, rii);
1074                         if (unlikely(err))
1075                                 goto free_out;
1076 
1077                         break;
1078 
1079                 case JFFS2_NODETYPE_INODE:
1080 
1081                         if (JFFS2_MIN_NODE_HEADER < sizeof(struct jffs2_raw_inode) &&
1082                             len < sizeof(struct jffs2_raw_inode)) {
1083                                 err = read_more(c, ref, sizeof(struct jffs2_raw_inode), &len, buf);
1084                                 if (unlikely(err))
1085                                         goto free_out;
1086                         }
1087 
1088                         err = read_dnode(c, ref, &node->i, len, rii);
1089                         if (unlikely(err))
1090                                 goto free_out;
1091 
1092                         break;
1093 
1094                 default:
1095                         if (JFFS2_MIN_NODE_HEADER < sizeof(struct jffs2_unknown_node) &&
1096                             len < sizeof(struct jffs2_unknown_node)) {
1097                                 err = read_more(c, ref, sizeof(struct jffs2_unknown_node), &len, buf);
1098                                 if (unlikely(err))
1099                                         goto free_out;
1100                         }
1101 
1102                         err = read_unknown(c, ref, &node->u);
1103                         if (unlikely(err))
1104                                 goto free_out;
1105 
1106                 }
1107         cont:
1108                 spin_lock(&c->erase_completion_lock);
1109         }
1110 
1111         spin_unlock(&c->erase_completion_lock);
1112         kfree(buf);
1113 
1114         f->highest_version = rii->highest_version;
1115 
1116         dbg_readinode("nodes of inode #%u were read, the highest version is %u, latest_mctime %u, mctime_ver %u.\n",
1117                       f->inocache->ino, rii->highest_version, rii->latest_mctime,
1118                       rii->mctime_ver);
1119         return 0;
1120 
1121  free_out:
1122         jffs2_free_tmp_dnode_info_list(&rii->tn_root);
1123         jffs2_free_full_dirent_list(rii->fds);
1124         rii->fds = NULL;
1125         kfree(buf);
1126         return err;
1127 }
1128 
1129 static int jffs2_do_read_inode_internal(struct jffs2_sb_info *c,
1130                                         struct jffs2_inode_info *f,
1131                                         struct jffs2_raw_inode *latest_node)
1132 {
1133         struct jffs2_readinode_info rii;
1134         uint32_t crc, new_size;
1135         size_t retlen;
1136         int ret;
1137 
1138         dbg_readinode("ino #%u pino/nlink is %d\n", f->inocache->ino,
1139                       f->inocache->pino_nlink);
1140 
1141         memset(&rii, 0, sizeof(rii));
1142 
1143         /* Grab all nodes relevant to this ino */
1144         ret = jffs2_get_inode_nodes(c, f, &rii);
1145 
1146         if (ret) {
1147                 JFFS2_ERROR("cannot read nodes for ino %u, returned error is %d\n", f->inocache->ino, ret);
1148                 if (f->inocache->state == INO_STATE_READING)
1149                         jffs2_set_inocache_state(c, f->inocache, INO_STATE_CHECKEDABSENT);
1150                 return ret;
1151         }
1152 
1153         ret = jffs2_build_inode_fragtree(c, f, &rii);
1154         if (ret) {
1155                 JFFS2_ERROR("Failed to build final fragtree for inode #%u: error %d\n",
1156                             f->inocache->ino, ret);
1157                 if (f->inocache->state == INO_STATE_READING)
1158                         jffs2_set_inocache_state(c, f->inocache, INO_STATE_CHECKEDABSENT);
1159                 jffs2_free_tmp_dnode_info_list(&rii.tn_root);
1160                 /* FIXME: We could at least crc-check them all */
1161                 if (rii.mdata_tn) {
1162                         jffs2_free_full_dnode(rii.mdata_tn->fn);
1163                         jffs2_free_tmp_dnode_info(rii.mdata_tn);
1164                         rii.mdata_tn = NULL;
1165                 }
1166                 return ret;
1167         }
1168 
1169         if (rii.mdata_tn) {
1170                 if (rii.mdata_tn->fn->raw == rii.latest_ref) {
1171                         f->metadata = rii.mdata_tn->fn;
1172                         jffs2_free_tmp_dnode_info(rii.mdata_tn);
1173                 } else {
1174                         jffs2_kill_tn(c, rii.mdata_tn);
1175                 }
1176                 rii.mdata_tn = NULL;
1177         }
1178 
1179         f->dents = rii.fds;
1180 
1181         jffs2_dbg_fragtree_paranoia_check_nolock(f);
1182 
1183         if (unlikely(!rii.latest_ref)) {
1184                 /* No data nodes for this inode. */
1185                 if (f->inocache->ino != 1) {
1186                         JFFS2_WARNING("no data nodes found for ino #%u\n", f->inocache->ino);
1187                         if (!rii.fds) {
1188                                 if (f->inocache->state == INO_STATE_READING)
1189                                         jffs2_set_inocache_state(c, f->inocache, INO_STATE_CHECKEDABSENT);
1190                                 return -EIO;
1191                         }
1192                         JFFS2_NOTICE("but it has children so we fake some modes for it\n");
1193                 }
1194                 latest_node->mode = cpu_to_jemode(S_IFDIR|S_IRUGO|S_IWUSR|S_IXUGO);
1195                 latest_node->version = cpu_to_je32(0);
1196                 latest_node->atime = latest_node->ctime = latest_node->mtime = cpu_to_je32(0);
1197                 latest_node->isize = cpu_to_je32(0);
1198                 latest_node->gid = cpu_to_je16(0);
1199                 latest_node->uid = cpu_to_je16(0);
1200                 if (f->inocache->state == INO_STATE_READING)
1201                         jffs2_set_inocache_state(c, f->inocache, INO_STATE_PRESENT);
1202                 return 0;
1203         }
1204 
1205         ret = jffs2_flash_read(c, ref_offset(rii.latest_ref), sizeof(*latest_node), &retlen, (void *)latest_node);
1206         if (ret || retlen != sizeof(*latest_node)) {
1207                 JFFS2_ERROR("failed to read from flash: error %d, %zd of %zd bytes read\n",
1208                         ret, retlen, sizeof(*latest_node));
1209                 /* FIXME: If this fails, there seems to be a memory leak. Find it. */
1210                 return ret ? ret : -EIO;
1211         }
1212 
1213         crc = crc32(0, latest_node, sizeof(*latest_node)-8);
1214         if (crc != je32_to_cpu(latest_node->node_crc)) {
1215                 JFFS2_ERROR("CRC failed for read_inode of inode %u at physical location 0x%x\n",
1216                         f->inocache->ino, ref_offset(rii.latest_ref));
1217                 return -EIO;
1218         }
1219 
1220         switch(jemode_to_cpu(latest_node->mode) & S_IFMT) {
1221         case S_IFDIR:
1222                 if (rii.mctime_ver > je32_to_cpu(latest_node->version)) {
1223                         /* The times in the latest_node are actually older than
1224                            mctime in the latest dirent. Cheat. */
1225                         latest_node->ctime = latest_node->mtime = cpu_to_je32(rii.latest_mctime);
1226                 }
1227                 break;
1228 
1229 
1230         case S_IFREG:
1231                 /* If it was a regular file, truncate it to the latest node's isize */
1232                 new_size = jffs2_truncate_fragtree(c, &f->fragtree, je32_to_cpu(latest_node->isize));
1233                 if (new_size != je32_to_cpu(latest_node->isize)) {
1234                         JFFS2_WARNING("Truncating ino #%u to %d bytes failed because it only had %d bytes to start with!\n",
1235                                       f->inocache->ino, je32_to_cpu(latest_node->isize), new_size);
1236                         latest_node->isize = cpu_to_je32(new_size);
1237                 }
1238                 break;
1239 
1240         case S_IFLNK:
1241                 /* Hack to work around broken isize in old symlink code.
1242                    Remove this when dwmw2 comes to his senses and stops
1243                    symlinks from being an entirely gratuitous special
1244                    case. */
1245                 if (!je32_to_cpu(latest_node->isize))
1246                         latest_node->isize = latest_node->dsize;
1247 
1248                 if (f->inocache->state != INO_STATE_CHECKING) {
1249                         /* Symlink's inode data is the target path. Read it and
1250                          * keep in RAM to facilitate quick follow symlink
1251                          * operation. */
1252                         uint32_t csize = je32_to_cpu(latest_node->csize);
1253                         if (csize > JFFS2_MAX_NAME_LEN)
1254                                 return -ENAMETOOLONG;
1255                         f->target = kmalloc(csize + 1, GFP_KERNEL);
1256                         if (!f->target) {
1257                                 JFFS2_ERROR("can't allocate %u bytes of memory for the symlink target path cache\n", csize);
1258                                 return -ENOMEM;
1259                         }
1260 
1261                         ret = jffs2_flash_read(c, ref_offset(rii.latest_ref) + sizeof(*latest_node),
1262                                                csize, &retlen, (char *)f->target);
1263 
1264                         if (ret || retlen != csize) {
1265                                 if (retlen != csize)
1266                                         ret = -EIO;
1267                                 kfree(f->target);
1268                                 f->target = NULL;
1269                                 return ret;
1270                         }
1271 
1272                         f->target[csize] = '\0';
1273                         dbg_readinode("symlink's target '%s' cached\n", f->target);
1274                 }
1275 
1276                 fallthrough;
1277 
1278         case S_IFBLK:
1279         case S_IFCHR:
1280                 /* Certain inode types should have only one data node, and it's
1281                    kept as the metadata node */
1282                 if (f->metadata) {
1283                         JFFS2_ERROR("Argh. Special inode #%u with mode 0%o had metadata node\n",
1284                                f->inocache->ino, jemode_to_cpu(latest_node->mode));
1285                         return -EIO;
1286                 }
1287                 if (!frag_first(&f->fragtree)) {
1288                         JFFS2_ERROR("Argh. Special inode #%u with mode 0%o has no fragments\n",
1289                                f->inocache->ino, jemode_to_cpu(latest_node->mode));
1290                         return -EIO;
1291                 }
1292                 /* ASSERT: f->fraglist != NULL */
1293                 if (frag_next(frag_first(&f->fragtree))) {
1294                         JFFS2_ERROR("Argh. Special inode #%u with mode 0x%x had more than one node\n",
1295                                f->inocache->ino, jemode_to_cpu(latest_node->mode));
1296                         /* FIXME: Deal with it - check crc32, check for duplicate node, check times and discard the older one */
1297                         return -EIO;
1298                 }
1299                 /* OK. We're happy */
1300                 f->metadata = frag_first(&f->fragtree)->node;
1301                 jffs2_free_node_frag(frag_first(&f->fragtree));
1302                 f->fragtree = RB_ROOT;
1303                 break;
1304         }
1305         if (f->inocache->state == INO_STATE_READING)
1306                 jffs2_set_inocache_state(c, f->inocache, INO_STATE_PRESENT);
1307 
1308         return 0;
1309 }
1310 
1311 /* Scan the list of all nodes present for this ino, build map of versions, etc. */
1312 int jffs2_do_read_inode(struct jffs2_sb_info *c, struct jffs2_inode_info *f,
1313                         uint32_t ino, struct jffs2_raw_inode *latest_node)
1314 {
1315         dbg_readinode("read inode #%u\n", ino);
1316 
1317  retry_inocache:
1318         spin_lock(&c->inocache_lock);
1319         f->inocache = jffs2_get_ino_cache(c, ino);
1320 
1321         if (f->inocache) {
1322                 /* Check its state. We may need to wait before we can use it */
1323                 switch(f->inocache->state) {
1324                 case INO_STATE_UNCHECKED:
1325                 case INO_STATE_CHECKEDABSENT:
1326                         f->inocache->state = INO_STATE_READING;
1327                         break;
1328 
1329                 case INO_STATE_CHECKING:
1330                 case INO_STATE_GC:
1331                         /* If it's in either of these states, we need
1332                            to wait for whoever's got it to finish and
1333                            put it back. */
1334                         dbg_readinode("waiting for ino #%u in state %d\n", ino, f->inocache->state);
1335                         sleep_on_spinunlock(&c->inocache_wq, &c->inocache_lock);
1336                         goto retry_inocache;
1337 
1338                 case INO_STATE_READING:
1339                 case INO_STATE_PRESENT:
1340                         /* Eep. This should never happen. It can
1341                         happen if Linux calls read_inode() again
1342                         before clear_inode() has finished though. */
1343                         JFFS2_ERROR("Eep. Trying to read_inode #%u when it's already in state %d!\n", ino, f->inocache->state);
1344                         /* Fail. That's probably better than allowing it to succeed */
1345                         f->inocache = NULL;
1346                         break;
1347 
1348                 default:
1349                         BUG();
1350                 }
1351         }
1352         spin_unlock(&c->inocache_lock);
1353 
1354         if (!f->inocache && ino == 1) {
1355                 /* Special case - no root inode on medium */
1356                 f->inocache = jffs2_alloc_inode_cache();
1357                 if (!f->inocache) {
1358                         JFFS2_ERROR("cannot allocate inocache for root inode\n");
1359                         return -ENOMEM;
1360                 }
1361                 dbg_readinode("creating inocache for root inode\n");
1362                 memset(f->inocache, 0, sizeof(struct jffs2_inode_cache));
1363                 f->inocache->ino = f->inocache->pino_nlink = 1;
1364                 f->inocache->nodes = (struct jffs2_raw_node_ref *)f->inocache;
1365                 f->inocache->state = INO_STATE_READING;
1366                 jffs2_add_ino_cache(c, f->inocache);
1367         }
1368         if (!f->inocache) {
1369                 JFFS2_ERROR("requested to read a nonexistent ino %u\n", ino);
1370                 return -ENOENT;
1371         }
1372 
1373         return jffs2_do_read_inode_internal(c, f, latest_node);
1374 }
1375 
1376 int jffs2_do_crccheck_inode(struct jffs2_sb_info *c, struct jffs2_inode_cache *ic)
1377 {
1378         struct jffs2_raw_inode n;
1379         struct jffs2_inode_info *f = kzalloc(sizeof(*f), GFP_KERNEL);
1380         int ret;
1381 
1382         if (!f)
1383                 return -ENOMEM;
1384 
1385         mutex_init(&f->sem);
1386         mutex_lock(&f->sem);
1387         f->inocache = ic;
1388 
1389         ret = jffs2_do_read_inode_internal(c, f, &n);
1390         mutex_unlock(&f->sem);
1391         jffs2_do_clear_inode(c, f);
1392         jffs2_xattr_do_crccheck_inode(c, ic);
1393         kfree (f);
1394         return ret;
1395 }
1396 
1397 void jffs2_do_clear_inode(struct jffs2_sb_info *c, struct jffs2_inode_info *f)
1398 {
1399         struct jffs2_full_dirent *fd, *fds;
1400         int deleted;
1401 
1402         jffs2_xattr_delete_inode(c, f->inocache);
1403         mutex_lock(&f->sem);
1404         deleted = f->inocache && !f->inocache->pino_nlink;
1405 
1406         if (f->inocache && f->inocache->state != INO_STATE_CHECKING)
1407                 jffs2_set_inocache_state(c, f->inocache, INO_STATE_CLEARING);
1408 
1409         if (f->metadata) {
1410                 if (deleted)
1411                         jffs2_mark_node_obsolete(c, f->metadata->raw);
1412                 jffs2_free_full_dnode(f->metadata);
1413         }
1414 
1415         jffs2_kill_fragtree(&f->fragtree, deleted?c:NULL);
1416 
1417         fds = f->dents;
1418         while(fds) {
1419                 fd = fds;
1420                 fds = fd->next;
1421                 jffs2_free_full_dirent(fd);
1422         }
1423 
1424         if (f->inocache && f->inocache->state != INO_STATE_CHECKING) {
1425                 jffs2_set_inocache_state(c, f->inocache, INO_STATE_CHECKEDABSENT);
1426                 if (f->inocache->nodes == (void *)f->inocache)
1427                         jffs2_del_ino_cache(c, f->inocache);
1428         }
1429 
1430         mutex_unlock(&f->sem);
1431 }
1432 

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