ocfs2: don't use MLF* in the file system
[linux-2.6.git] / fs / ocfs2 / extent_map.c
1 /* -*- mode: c; c-basic-offset: 8; -*-
2  * vim: noexpandtab sw=8 ts=8 sts=0:
3  *
4  * extent_map.c
5  *
6  * In-memory extent map for OCFS2.  Man, this code was prettier in
7  * the library.
8  *
9  * Copyright (C) 2004 Oracle.  All rights reserved.
10  *
11  * This program is free software; you can redistribute it and/or
12  * modify it under the terms of the GNU General Public
13  * License, version 2,  as published by the Free Software Foundation.
14  *
15  * This program is distributed in the hope that it will be useful,
16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
18  * General Public License for more details.
19  *
20  * You should have received a copy of the GNU General Public
21  * License along with this program; if not, write to the
22  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
23  * Boston, MA 021110-1307, USA.
24  */
25
26 #include <linux/fs.h>
27 #include <linux/init.h>
28 #include <linux/types.h>
29 #include <linux/slab.h>
30 #include <linux/rbtree.h>
31
32 #define MLOG_MASK_PREFIX ML_EXTENT_MAP
33 #include <cluster/masklog.h>
34
35 #include "ocfs2.h"
36
37 #include "extent_map.h"
38 #include "inode.h"
39 #include "super.h"
40
41 #include "buffer_head_io.h"
42
43
44 /*
45  * SUCK SUCK SUCK
46  * Our headers are so bad that struct ocfs2_extent_map is in ocfs.h
47  */
48
49 struct ocfs2_extent_map_entry {
50         struct rb_node e_node;
51         int e_tree_depth;
52         struct ocfs2_extent_rec e_rec;
53 };
54
55 struct ocfs2_em_insert_context {
56         int need_left;
57         int need_right;
58         struct ocfs2_extent_map_entry *new_ent;
59         struct ocfs2_extent_map_entry *old_ent;
60         struct ocfs2_extent_map_entry *left_ent;
61         struct ocfs2_extent_map_entry *right_ent;
62 };
63
64 static kmem_cache_t *ocfs2_em_ent_cachep = NULL;
65
66
67 static struct ocfs2_extent_map_entry *
68 ocfs2_extent_map_lookup(struct ocfs2_extent_map *em,
69                         u32 cpos, u32 clusters,
70                         struct rb_node ***ret_p,
71                         struct rb_node **ret_parent);
72 static int ocfs2_extent_map_insert(struct inode *inode,
73                                    struct ocfs2_extent_rec *rec,
74                                    int tree_depth);
75 static int ocfs2_extent_map_insert_entry(struct ocfs2_extent_map *em,
76                                          struct ocfs2_extent_map_entry *ent);
77 static int ocfs2_extent_map_find_leaf(struct inode *inode,
78                                       u32 cpos, u32 clusters,
79                                       struct ocfs2_extent_list *el);
80 static int ocfs2_extent_map_lookup_read(struct inode *inode,
81                                         u32 cpos, u32 clusters,
82                                         struct ocfs2_extent_map_entry **ret_ent);
83 static int ocfs2_extent_map_try_insert(struct inode *inode,
84                                        struct ocfs2_extent_rec *rec,
85                                        int tree_depth,
86                                        struct ocfs2_em_insert_context *ctxt);
87
88 /* returns 1 only if the rec contains all the given clusters -- that is that
89  * rec's cpos is <= the cluster cpos and that the rec endpoint (cpos +
90  * clusters) is >= the argument's endpoint */
91 static int ocfs2_extent_rec_contains_clusters(struct ocfs2_extent_rec *rec,
92                                               u32 cpos, u32 clusters)
93 {
94         if (le32_to_cpu(rec->e_cpos) > cpos)
95                 return 0;
96         if (cpos + clusters > le32_to_cpu(rec->e_cpos) + 
97                               le32_to_cpu(rec->e_clusters))
98                 return 0;
99         return 1;
100 }
101
102
103 /*
104  * Find an entry in the tree that intersects the region passed in.
105  * Note that this will find straddled intervals, it is up to the
106  * callers to enforce any boundary conditions.
107  *
108  * Callers must hold ip_lock.  This lookup is not guaranteed to return
109  * a tree_depth 0 match, and as such can race inserts if the lock
110  * were not held.
111  *
112  * The rb_node garbage lets insertion share the search.  Trivial
113  * callers pass NULL.
114  */
115 static struct ocfs2_extent_map_entry *
116 ocfs2_extent_map_lookup(struct ocfs2_extent_map *em,
117                         u32 cpos, u32 clusters,
118                         struct rb_node ***ret_p,
119                         struct rb_node **ret_parent)
120 {
121         struct rb_node **p = &em->em_extents.rb_node;
122         struct rb_node *parent = NULL;
123         struct ocfs2_extent_map_entry *ent = NULL;
124
125         while (*p)
126         {
127                 parent = *p;
128                 ent = rb_entry(parent, struct ocfs2_extent_map_entry,
129                                e_node);
130                 if ((cpos + clusters) <= le32_to_cpu(ent->e_rec.e_cpos)) {
131                         p = &(*p)->rb_left;
132                         ent = NULL;
133                 } else if (cpos >= (le32_to_cpu(ent->e_rec.e_cpos) +
134                                     le32_to_cpu(ent->e_rec.e_clusters))) {
135                         p = &(*p)->rb_right;
136                         ent = NULL;
137                 } else
138                         break;
139         }
140
141         if (ret_p != NULL)
142                 *ret_p = p;
143         if (ret_parent != NULL)
144                 *ret_parent = parent;
145         return ent;
146 }
147
148 /*
149  * Find the leaf containing the interval we want.  While we're on our
150  * way down the tree, fill in every record we see at any depth, because
151  * we might want it later.
152  *
153  * Note that this code is run without ip_lock.  That's because it
154  * sleeps while reading.  If someone is also filling the extent list at
155  * the same time we are, we might have to restart.
156  */
157 static int ocfs2_extent_map_find_leaf(struct inode *inode,
158                                       u32 cpos, u32 clusters,
159                                       struct ocfs2_extent_list *el)
160 {
161         int i, ret;
162         struct buffer_head *eb_bh = NULL;
163         u64 blkno;
164         u32 rec_end;
165         struct ocfs2_extent_block *eb;
166         struct ocfs2_extent_rec *rec;
167
168         /*
169          * The bh data containing the el cannot change here, because
170          * we hold alloc_sem.  So we can do this without other
171          * locks.
172          */
173         while (el->l_tree_depth)
174         {
175                 blkno = 0;
176                 for (i = 0; i < le16_to_cpu(el->l_next_free_rec); i++) {
177                         rec = &el->l_recs[i];
178                         rec_end = (le32_to_cpu(rec->e_cpos) +
179                                    le32_to_cpu(rec->e_clusters));
180
181                         ret = -EBADR;
182                         if (rec_end > OCFS2_I(inode)->ip_clusters) {
183                                 mlog_errno(ret);
184                                 ocfs2_error(inode->i_sb,
185                                             "Extent %d at e_blkno %llu of inode %llu goes past ip_clusters of %u\n",
186                                             i,
187                                             (unsigned long long)le64_to_cpu(rec->e_blkno),
188                                             (unsigned long long)OCFS2_I(inode)->ip_blkno,
189                                             OCFS2_I(inode)->ip_clusters);
190                                 goto out_free;
191                         }
192
193                         if (rec_end <= cpos) {
194                                 ret = ocfs2_extent_map_insert(inode, rec,
195                                                 le16_to_cpu(el->l_tree_depth));
196                                 if (ret && (ret != -EEXIST)) {
197                                         mlog_errno(ret);
198                                         goto out_free;
199                                 }
200                                 continue;
201                         }
202                         if ((cpos + clusters) <= le32_to_cpu(rec->e_cpos)) {
203                                 ret = ocfs2_extent_map_insert(inode, rec,
204                                                 le16_to_cpu(el->l_tree_depth));
205                                 if (ret && (ret != -EEXIST)) {
206                                         mlog_errno(ret);
207                                         goto out_free;
208                                 }
209                                 continue;
210                         }
211
212                         /*
213                          * We've found a record that matches our
214                          * interval.  We don't insert it because we're
215                          * about to traverse it.
216                          */
217
218                         /* Check to see if we're stradling */
219                         ret = -ESRCH;
220                         if (!ocfs2_extent_rec_contains_clusters(rec,
221                                                                 cpos,
222                                                                 clusters)) {
223                                 mlog_errno(ret);
224                                 goto out_free;
225                         }
226
227                         /*
228                          * If we've already found a record, the el has
229                          * two records covering the same interval.
230                          * EEEK!
231                          */
232                         ret = -EBADR;
233                         if (blkno) {
234                                 mlog_errno(ret);
235                                 ocfs2_error(inode->i_sb,
236                                             "Multiple extents for (cpos = %u, clusters = %u) on inode %llu; e_blkno %llu and rec %d at e_blkno %llu\n",
237                                             cpos, clusters,
238                                             (unsigned long long)OCFS2_I(inode)->ip_blkno,
239                                             (unsigned long long)blkno, i,
240                                             (unsigned long long)le64_to_cpu(rec->e_blkno));
241                                 goto out_free;
242                         }
243
244                         blkno = le64_to_cpu(rec->e_blkno);
245                 }
246
247                 /*
248                  * We don't support holes, and we're still up
249                  * in the branches, so we'd better have found someone
250                  */
251                 ret = -EBADR;
252                 if (!blkno) {
253                         ocfs2_error(inode->i_sb,
254                                     "No record found for (cpos = %u, clusters = %u) on inode %llu\n",
255                                     cpos, clusters,
256                                     (unsigned long long)OCFS2_I(inode)->ip_blkno);
257                         mlog_errno(ret);
258                         goto out_free;
259                 }
260
261                 if (eb_bh) {
262                         brelse(eb_bh);
263                         eb_bh = NULL;
264                 }
265                 ret = ocfs2_read_block(OCFS2_SB(inode->i_sb),
266                                        blkno, &eb_bh, OCFS2_BH_CACHED,
267                                        inode);
268                 if (ret) {
269                         mlog_errno(ret);
270                         goto out_free;
271                 }
272                 eb = (struct ocfs2_extent_block *)eb_bh->b_data;
273                 if (!OCFS2_IS_VALID_EXTENT_BLOCK(eb)) {
274                         OCFS2_RO_ON_INVALID_EXTENT_BLOCK(inode->i_sb, eb);
275                         ret = -EIO;
276                         goto out_free;
277                 }
278                 el = &eb->h_list;
279         }
280
281         BUG_ON(el->l_tree_depth);
282
283         for (i = 0; i < le16_to_cpu(el->l_next_free_rec); i++) {
284                 rec = &el->l_recs[i];
285
286                 if ((le32_to_cpu(rec->e_cpos) + le32_to_cpu(rec->e_clusters)) >
287                     OCFS2_I(inode)->ip_clusters) {
288                         ret = -EBADR;
289                         mlog_errno(ret);
290                         ocfs2_error(inode->i_sb,
291                                     "Extent %d at e_blkno %llu of inode %llu goes past ip_clusters of %u\n",
292                                     i,
293                                     (unsigned long long)le64_to_cpu(rec->e_blkno),
294                                     (unsigned long long)OCFS2_I(inode)->ip_blkno,
295                                     OCFS2_I(inode)->ip_clusters);
296                         return ret;
297                 }
298
299                 ret = ocfs2_extent_map_insert(inode, rec,
300                                               le16_to_cpu(el->l_tree_depth));
301                 if (ret) {
302                         mlog_errno(ret);
303                         goto out_free;
304                 }
305         }
306
307         ret = 0;
308
309 out_free:
310         if (eb_bh)
311                 brelse(eb_bh);
312
313         return ret;
314 }
315
316 /*
317  * This lookup actually will read from disk.  It has one invariant:
318  * It will never re-traverse blocks.  This means that all inserts should
319  * be new regions or more granular regions (both allowed by insert).
320  */
321 static int ocfs2_extent_map_lookup_read(struct inode *inode,
322                                         u32 cpos,
323                                         u32 clusters,
324                                         struct ocfs2_extent_map_entry **ret_ent)
325 {
326         int ret;
327         u64 blkno;
328         struct ocfs2_extent_map *em = &OCFS2_I(inode)->ip_map;
329         struct ocfs2_extent_map_entry *ent;
330         struct buffer_head *bh = NULL;
331         struct ocfs2_extent_block *eb;
332         struct ocfs2_dinode *di;
333         struct ocfs2_extent_list *el;
334
335         spin_lock(&OCFS2_I(inode)->ip_lock);
336         ent = ocfs2_extent_map_lookup(em, cpos, clusters, NULL, NULL);
337         if (ent) {
338                 if (!ent->e_tree_depth) {
339                         spin_unlock(&OCFS2_I(inode)->ip_lock);
340                         *ret_ent = ent;
341                         return 0;
342                 }
343                 blkno = le64_to_cpu(ent->e_rec.e_blkno);
344                 spin_unlock(&OCFS2_I(inode)->ip_lock);
345
346                 ret = ocfs2_read_block(OCFS2_SB(inode->i_sb), blkno, &bh,
347                                        OCFS2_BH_CACHED, inode);
348                 if (ret) {
349                         mlog_errno(ret);
350                         if (bh)
351                                 brelse(bh);
352                         return ret;
353                 }
354                 eb = (struct ocfs2_extent_block *)bh->b_data;
355                 if (!OCFS2_IS_VALID_EXTENT_BLOCK(eb)) {
356                         OCFS2_RO_ON_INVALID_EXTENT_BLOCK(inode->i_sb, eb);
357                         brelse(bh);
358                         return -EIO;
359                 }
360                 el = &eb->h_list;
361         } else {
362                 spin_unlock(&OCFS2_I(inode)->ip_lock);
363
364                 ret = ocfs2_read_block(OCFS2_SB(inode->i_sb),
365                                        OCFS2_I(inode)->ip_blkno, &bh,
366                                        OCFS2_BH_CACHED, inode);
367                 if (ret) {
368                         mlog_errno(ret);
369                         if (bh)
370                                 brelse(bh);
371                         return ret;
372                 }
373                 di = (struct ocfs2_dinode *)bh->b_data;
374                 if (!OCFS2_IS_VALID_DINODE(di)) {
375                         brelse(bh);
376                         OCFS2_RO_ON_INVALID_DINODE(inode->i_sb, di);
377                         return -EIO;
378                 }
379                 el = &di->id2.i_list;
380         }
381
382         ret = ocfs2_extent_map_find_leaf(inode, cpos, clusters, el);
383         brelse(bh);
384         if (ret) {
385                 mlog_errno(ret);
386                 return ret;
387         }
388
389         ent = ocfs2_extent_map_lookup(em, cpos, clusters, NULL, NULL);
390         if (!ent) {
391                 ret = -ESRCH;
392                 mlog_errno(ret);
393                 return ret;
394         }
395
396         /* FIXME: Make sure this isn't a corruption */
397         BUG_ON(ent->e_tree_depth);
398
399         *ret_ent = ent;
400
401         return 0;
402 }
403
404 /*
405  * Callers must hold ip_lock.  This can insert pieces of the tree,
406  * thus racing lookup if the lock weren't held.
407  */
408 static int ocfs2_extent_map_insert_entry(struct ocfs2_extent_map *em,
409                                          struct ocfs2_extent_map_entry *ent)
410 {
411         struct rb_node **p, *parent;
412         struct ocfs2_extent_map_entry *old_ent;
413
414         old_ent = ocfs2_extent_map_lookup(em, le32_to_cpu(ent->e_rec.e_cpos),
415                                           le32_to_cpu(ent->e_rec.e_clusters),
416                                           &p, &parent);
417         if (old_ent)
418                 return -EEXIST;
419
420         rb_link_node(&ent->e_node, parent, p);
421         rb_insert_color(&ent->e_node, &em->em_extents);
422
423         return 0;
424 }
425
426
427 /*
428  * Simple rule: on any return code other than -EAGAIN, anything left
429  * in the insert_context will be freed.
430  */
431 static int ocfs2_extent_map_try_insert(struct inode *inode,
432                                        struct ocfs2_extent_rec *rec,
433                                        int tree_depth,
434                                        struct ocfs2_em_insert_context *ctxt)
435 {
436         int ret;
437         struct ocfs2_extent_map *em = &OCFS2_I(inode)->ip_map;
438         struct ocfs2_extent_map_entry *old_ent;
439
440         ctxt->need_left = 0;
441         ctxt->need_right = 0;
442         ctxt->old_ent = NULL;
443
444         spin_lock(&OCFS2_I(inode)->ip_lock);
445         ret = ocfs2_extent_map_insert_entry(em, ctxt->new_ent);
446         if (!ret) {
447                 ctxt->new_ent = NULL;
448                 goto out_unlock;
449         }
450
451         old_ent = ocfs2_extent_map_lookup(em, le32_to_cpu(rec->e_cpos),
452                                           le32_to_cpu(rec->e_clusters), NULL,
453                                           NULL);
454
455         BUG_ON(!old_ent);
456
457         ret = -EEXIST;
458         if (old_ent->e_tree_depth < tree_depth)
459                 goto out_unlock;
460
461         if (old_ent->e_tree_depth == tree_depth) {
462                 if (!memcmp(rec, &old_ent->e_rec,
463                             sizeof(struct ocfs2_extent_rec)))
464                         ret = 0;
465
466                 /* FIXME: Should this be ESRCH/EBADR??? */
467                 goto out_unlock;
468         }
469
470         /*
471          * We do it in this order specifically so that no actual tree
472          * changes occur until we have all the pieces we need.  We
473          * don't want malloc failures to leave an inconsistent tree.
474          * Whenever we drop the lock, another process could be
475          * inserting.  Also note that, if another process just beat us
476          * to an insert, we might not need the same pieces we needed
477          * the first go round.  In the end, the pieces we need will
478          * be used, and the pieces we don't will be freed.
479          */
480         ctxt->need_left = !!(le32_to_cpu(rec->e_cpos) >
481                              le32_to_cpu(old_ent->e_rec.e_cpos));
482         ctxt->need_right = !!((le32_to_cpu(old_ent->e_rec.e_cpos) +
483                                le32_to_cpu(old_ent->e_rec.e_clusters)) >
484                               (le32_to_cpu(rec->e_cpos) + le32_to_cpu(rec->e_clusters)));
485         ret = -EAGAIN;
486         if (ctxt->need_left) {
487                 if (!ctxt->left_ent)
488                         goto out_unlock;
489                 *(ctxt->left_ent) = *old_ent;
490                 ctxt->left_ent->e_rec.e_clusters =
491                         cpu_to_le32(le32_to_cpu(rec->e_cpos) -
492                                     le32_to_cpu(ctxt->left_ent->e_rec.e_cpos));
493         }
494         if (ctxt->need_right) {
495                 if (!ctxt->right_ent)
496                         goto out_unlock;
497                 *(ctxt->right_ent) = *old_ent;
498                 ctxt->right_ent->e_rec.e_cpos =
499                         cpu_to_le32(le32_to_cpu(rec->e_cpos) +
500                                     le32_to_cpu(rec->e_clusters));
501                 ctxt->right_ent->e_rec.e_clusters =
502                         cpu_to_le32((le32_to_cpu(old_ent->e_rec.e_cpos) +
503                                      le32_to_cpu(old_ent->e_rec.e_clusters)) -
504                                     le32_to_cpu(ctxt->right_ent->e_rec.e_cpos));
505         }
506
507         rb_erase(&old_ent->e_node, &em->em_extents);
508         /* Now that he's erased, set him up for deletion */
509         ctxt->old_ent = old_ent;
510
511         if (ctxt->need_left) {
512                 ret = ocfs2_extent_map_insert_entry(em,
513                                                     ctxt->left_ent);
514                 if (ret)
515                         goto out_unlock;
516                 ctxt->left_ent = NULL;
517         }
518
519         if (ctxt->need_right) {
520                 ret = ocfs2_extent_map_insert_entry(em,
521                                                     ctxt->right_ent);
522                 if (ret)
523                         goto out_unlock;
524                 ctxt->right_ent = NULL;
525         }
526
527         ret = ocfs2_extent_map_insert_entry(em, ctxt->new_ent);
528
529         if (!ret)
530                 ctxt->new_ent = NULL;
531
532 out_unlock:
533         spin_unlock(&OCFS2_I(inode)->ip_lock);
534
535         return ret;
536 }
537
538
539 static int ocfs2_extent_map_insert(struct inode *inode,
540                                    struct ocfs2_extent_rec *rec,
541                                    int tree_depth)
542 {
543         int ret;
544         struct ocfs2_em_insert_context ctxt = {0, };
545
546         if ((le32_to_cpu(rec->e_cpos) + le32_to_cpu(rec->e_clusters)) >
547             OCFS2_I(inode)->ip_map.em_clusters) {
548                 ret = -EBADR;
549                 mlog_errno(ret);
550                 return ret;
551         }
552
553         /* Zero e_clusters means a truncated tail record.  It better be EOF */
554         if (!rec->e_clusters) {
555                 if ((le32_to_cpu(rec->e_cpos) + le32_to_cpu(rec->e_clusters)) !=
556                     OCFS2_I(inode)->ip_map.em_clusters) {
557                         ret = -EBADR;
558                         mlog_errno(ret);
559                         ocfs2_error(inode->i_sb,
560                                     "Zero e_clusters on non-tail extent record at e_blkno %llu on inode %llu\n",
561                                     (unsigned long long)le64_to_cpu(rec->e_blkno),
562                                     (unsigned long long)OCFS2_I(inode)->ip_blkno);
563                         return ret;
564                 }
565
566                 /* Ignore the truncated tail */
567                 return 0;
568         }
569
570         ret = -ENOMEM;
571         ctxt.new_ent = kmem_cache_alloc(ocfs2_em_ent_cachep,
572                                         GFP_KERNEL);
573         if (!ctxt.new_ent) {
574                 mlog_errno(ret);
575                 return ret;
576         }
577
578         ctxt.new_ent->e_rec = *rec;
579         ctxt.new_ent->e_tree_depth = tree_depth;
580
581         do {
582                 ret = -ENOMEM;
583                 if (ctxt.need_left && !ctxt.left_ent) {
584                         ctxt.left_ent =
585                                 kmem_cache_alloc(ocfs2_em_ent_cachep,
586                                                  GFP_KERNEL);
587                         if (!ctxt.left_ent)
588                                 break;
589                 }
590                 if (ctxt.need_right && !ctxt.right_ent) {
591                         ctxt.right_ent =
592                                 kmem_cache_alloc(ocfs2_em_ent_cachep,
593                                                  GFP_KERNEL);
594                         if (!ctxt.right_ent)
595                                 break;
596                 }
597
598                 ret = ocfs2_extent_map_try_insert(inode, rec,
599                                                   tree_depth, &ctxt);
600         } while (ret == -EAGAIN);
601
602         if (ret < 0)
603                 mlog_errno(ret);
604
605         if (ctxt.left_ent)
606                 kmem_cache_free(ocfs2_em_ent_cachep, ctxt.left_ent);
607         if (ctxt.right_ent)
608                 kmem_cache_free(ocfs2_em_ent_cachep, ctxt.right_ent);
609         if (ctxt.old_ent)
610                 kmem_cache_free(ocfs2_em_ent_cachep, ctxt.old_ent);
611         if (ctxt.new_ent)
612                 kmem_cache_free(ocfs2_em_ent_cachep, ctxt.new_ent);
613
614         return ret;
615 }
616
617 /*
618  * Append this record to the tail of the extent map.  It must be
619  * tree_depth 0.  The record might be an extension of an existing
620  * record, and as such that needs to be handled.  eg:
621  *
622  * Existing record in the extent map:
623  *
624  *      cpos = 10, len = 10
625  *      |---------|
626  *
627  * New Record:
628  *
629  *      cpos = 10, len = 20
630  *      |------------------|
631  *
632  * The passed record is the new on-disk record.  The new_clusters value
633  * is how many clusters were added to the file.  If the append is a
634  * contiguous append, the new_clusters has been added to
635  * rec->e_clusters.  If the append is an entirely new extent, then
636  * rec->e_clusters is == new_clusters.
637  */
638 int ocfs2_extent_map_append(struct inode *inode,
639                             struct ocfs2_extent_rec *rec,
640                             u32 new_clusters)
641 {
642         int ret;
643         struct ocfs2_extent_map *em = &OCFS2_I(inode)->ip_map;
644         struct ocfs2_extent_map_entry *ent;
645         struct ocfs2_extent_rec *old;
646
647         BUG_ON(!new_clusters);
648         BUG_ON(le32_to_cpu(rec->e_clusters) < new_clusters);
649
650         if (em->em_clusters < OCFS2_I(inode)->ip_clusters) {
651                 /*
652                  * Size changed underneath us on disk.  Drop any
653                  * straddling records and update our idea of
654                  * i_clusters
655                  */
656                 ocfs2_extent_map_drop(inode, em->em_clusters - 1);
657                 em->em_clusters = OCFS2_I(inode)->ip_clusters;
658         }
659
660         mlog_bug_on_msg((le32_to_cpu(rec->e_cpos) +
661                          le32_to_cpu(rec->e_clusters)) !=
662                         (em->em_clusters + new_clusters),
663                         "Inode %llu:\n"
664                         "rec->e_cpos = %u + rec->e_clusters = %u = %u\n"
665                         "em->em_clusters = %u + new_clusters = %u = %u\n",
666                         (unsigned long long)OCFS2_I(inode)->ip_blkno,
667                         le32_to_cpu(rec->e_cpos), le32_to_cpu(rec->e_clusters),
668                         le32_to_cpu(rec->e_cpos) + le32_to_cpu(rec->e_clusters),
669                         em->em_clusters, new_clusters,
670                         em->em_clusters + new_clusters);
671
672         em->em_clusters += new_clusters;
673
674         ret = -ENOENT;
675         if (le32_to_cpu(rec->e_clusters) > new_clusters) {
676                 /* This is a contiguous append */
677                 ent = ocfs2_extent_map_lookup(em, le32_to_cpu(rec->e_cpos), 1,
678                                               NULL, NULL);
679                 if (ent) {
680                         old = &ent->e_rec;
681                         BUG_ON((le32_to_cpu(rec->e_cpos) +
682                                 le32_to_cpu(rec->e_clusters)) !=
683                                  (le32_to_cpu(old->e_cpos) +
684                                   le32_to_cpu(old->e_clusters) +
685                                   new_clusters));
686                         if (ent->e_tree_depth == 0) {
687                                 BUG_ON(le32_to_cpu(old->e_cpos) !=
688                                        le32_to_cpu(rec->e_cpos));
689                                 BUG_ON(le64_to_cpu(old->e_blkno) !=
690                                        le64_to_cpu(rec->e_blkno));
691                                 ret = 0;
692                         }
693                         /*
694                          * Let non-leafs fall through as -ENOENT to
695                          * force insertion of the new leaf.
696                          */
697                         le32_add_cpu(&old->e_clusters, new_clusters);
698                 }
699         }
700
701         if (ret == -ENOENT)
702                 ret = ocfs2_extent_map_insert(inode, rec, 0);
703         if (ret < 0)
704                 mlog_errno(ret);
705         return ret;
706 }
707
708 #if 0
709 /* Code here is included but defined out as it completes the extent
710  * map api and may be used in the future. */
711
712 /*
713  * Look up the record containing this cluster offset.  This record is
714  * part of the extent map.  Do not free it.  Any changes you make to
715  * it will reflect in the extent map.  So, if your last extent
716  * is (cpos = 10, clusters = 10) and you truncate the file by 5
717  * clusters, you can do:
718  *
719  * ret = ocfs2_extent_map_get_rec(em, orig_size - 5, &rec);
720  * rec->e_clusters -= 5;
721  *
722  * The lookup does not read from disk.  If the map isn't filled in for
723  * an entry, you won't find it.
724  *
725  * Also note that the returned record is valid until alloc_sem is
726  * dropped.  After that, truncate and extend can happen.  Caveat Emptor.
727  */
728 int ocfs2_extent_map_get_rec(struct inode *inode, u32 cpos,
729                              struct ocfs2_extent_rec **rec,
730                              int *tree_depth)
731 {
732         int ret = -ENOENT;
733         struct ocfs2_extent_map *em = &OCFS2_I(inode)->ip_map;
734         struct ocfs2_extent_map_entry *ent;
735
736         *rec = NULL;
737
738         if (cpos >= OCFS2_I(inode)->ip_clusters)
739                 return -EINVAL;
740
741         if (cpos >= em->em_clusters) {
742                 /*
743                  * Size changed underneath us on disk.  Drop any
744                  * straddling records and update our idea of
745                  * i_clusters
746                  */
747                 ocfs2_extent_map_drop(inode, em->em_clusters - 1);
748                 em->em_clusters = OCFS2_I(inode)->ip_clusters ;
749         }
750
751         ent = ocfs2_extent_map_lookup(&OCFS2_I(inode)->ip_map, cpos, 1,
752                                       NULL, NULL);
753
754         if (ent) {
755                 *rec = &ent->e_rec;
756                 if (tree_depth)
757                         *tree_depth = ent->e_tree_depth;
758                 ret = 0;
759         }
760
761         return ret;
762 }
763
764 int ocfs2_extent_map_get_clusters(struct inode *inode,
765                                   u32 v_cpos, int count,
766                                   u32 *p_cpos, int *ret_count)
767 {
768         int ret;
769         u32 coff, ccount;
770         struct ocfs2_extent_map *em = &OCFS2_I(inode)->ip_map;
771         struct ocfs2_extent_map_entry *ent = NULL;
772
773         *p_cpos = ccount = 0;
774
775         if ((v_cpos + count) > OCFS2_I(inode)->ip_clusters)
776                 return -EINVAL;
777
778         if ((v_cpos + count) > em->em_clusters) {
779                 /*
780                  * Size changed underneath us on disk.  Drop any
781                  * straddling records and update our idea of
782                  * i_clusters
783                  */
784                 ocfs2_extent_map_drop(inode, em->em_clusters - 1);
785                 em->em_clusters = OCFS2_I(inode)->ip_clusters;
786         }
787
788
789         ret = ocfs2_extent_map_lookup_read(inode, v_cpos, count, &ent);
790         if (ret)
791                 return ret;
792
793         if (ent) {
794                 /* We should never find ourselves straddling an interval */
795                 if (!ocfs2_extent_rec_contains_clusters(&ent->e_rec,
796                                                         v_cpos,
797                                                         count))
798                         return -ESRCH;
799
800                 coff = v_cpos - le32_to_cpu(ent->e_rec.e_cpos);
801                 *p_cpos = ocfs2_blocks_to_clusters(inode->i_sb,
802                                 le64_to_cpu(ent->e_rec.e_blkno)) +
803                           coff;
804
805                 if (ret_count)
806                         *ret_count = le32_to_cpu(ent->e_rec.e_clusters) - coff;
807
808                 return 0;
809         }
810
811
812         return -ENOENT;
813 }
814
815 #endif  /*  0  */
816
817 int ocfs2_extent_map_get_blocks(struct inode *inode,
818                                 u64 v_blkno, int count,
819                                 u64 *p_blkno, int *ret_count)
820 {
821         int ret;
822         u64 boff;
823         u32 cpos, clusters;
824         int bpc = ocfs2_clusters_to_blocks(inode->i_sb, 1);
825         struct ocfs2_extent_map_entry *ent = NULL;
826         struct ocfs2_extent_map *em = &OCFS2_I(inode)->ip_map;
827         struct ocfs2_extent_rec *rec;
828
829         *p_blkno = 0;
830
831         cpos = ocfs2_blocks_to_clusters(inode->i_sb, v_blkno);
832         clusters = ocfs2_blocks_to_clusters(inode->i_sb,
833                                             (u64)count + bpc - 1);
834         if ((cpos + clusters) > OCFS2_I(inode)->ip_clusters) {
835                 ret = -EINVAL;
836                 mlog_errno(ret);
837                 return ret;
838         }
839
840         if ((cpos + clusters) > em->em_clusters) {
841                 /*
842                  * Size changed underneath us on disk.  Drop any
843                  * straddling records and update our idea of
844                  * i_clusters
845                  */
846                 ocfs2_extent_map_drop(inode, em->em_clusters - 1);
847                 em->em_clusters = OCFS2_I(inode)->ip_clusters;
848         }
849
850         ret = ocfs2_extent_map_lookup_read(inode, cpos, clusters, &ent);
851         if (ret) {
852                 mlog_errno(ret);
853                 return ret;
854         }
855
856         if (ent)
857         {
858                 rec = &ent->e_rec;
859
860                 /* We should never find ourselves straddling an interval */
861                 if (!ocfs2_extent_rec_contains_clusters(rec, cpos, clusters)) {
862                         ret = -ESRCH;
863                         mlog_errno(ret);
864                         return ret;
865                 }
866
867                 boff = ocfs2_clusters_to_blocks(inode->i_sb, cpos -
868                                                 le32_to_cpu(rec->e_cpos));
869                 boff += (v_blkno & (u64)(bpc - 1));
870                 *p_blkno = le64_to_cpu(rec->e_blkno) + boff;
871
872                 if (ret_count) {
873                         *ret_count = ocfs2_clusters_to_blocks(inode->i_sb,
874                                         le32_to_cpu(rec->e_clusters)) - boff;
875                 }
876
877                 return 0;
878         }
879
880         return -ENOENT;
881 }
882
883 int ocfs2_extent_map_init(struct inode *inode)
884 {
885         struct ocfs2_extent_map *em = &OCFS2_I(inode)->ip_map;
886
887         em->em_extents = RB_ROOT;
888         em->em_clusters = 0;
889
890         return 0;
891 }
892
893 /* Needs the lock */
894 static void __ocfs2_extent_map_drop(struct inode *inode,
895                                     u32 new_clusters,
896                                     struct rb_node **free_head,
897                                     struct ocfs2_extent_map_entry **tail_ent)
898 {
899         struct rb_node *node, *next;
900         struct ocfs2_extent_map *em = &OCFS2_I(inode)->ip_map;
901         struct ocfs2_extent_map_entry *ent;
902
903         *free_head = NULL;
904
905         ent = NULL;
906         node = rb_last(&em->em_extents);
907         while (node)
908         {
909                 next = rb_prev(node);
910
911                 ent = rb_entry(node, struct ocfs2_extent_map_entry,
912                                e_node);
913                 if (le32_to_cpu(ent->e_rec.e_cpos) < new_clusters)
914                         break;
915
916                 rb_erase(&ent->e_node, &em->em_extents);
917
918                 node->rb_right = *free_head;
919                 *free_head = node;
920
921                 ent = NULL;
922                 node = next;
923         }
924
925         /* Do we have an entry straddling new_clusters? */
926         if (tail_ent) {
927                 if (ent &&
928                     ((le32_to_cpu(ent->e_rec.e_cpos) +
929                       le32_to_cpu(ent->e_rec.e_clusters)) > new_clusters))
930                         *tail_ent = ent;
931                 else
932                         *tail_ent = NULL;
933         }
934 }
935
936 static void __ocfs2_extent_map_drop_cleanup(struct rb_node *free_head)
937 {
938         struct rb_node *node;
939         struct ocfs2_extent_map_entry *ent;
940
941         while (free_head) {
942                 node = free_head;
943                 free_head = node->rb_right;
944
945                 ent = rb_entry(node, struct ocfs2_extent_map_entry,
946                                e_node);
947                 kmem_cache_free(ocfs2_em_ent_cachep, ent);
948         }
949 }
950
951 /*
952  * Remove all entries past new_clusters, inclusive of an entry that
953  * contains new_clusters.  This is effectively a cache forget.
954  *
955  * If you want to also clip the last extent by some number of clusters,
956  * you need to call ocfs2_extent_map_trunc().
957  * This code does not check or modify ip_clusters.
958  */
959 int ocfs2_extent_map_drop(struct inode *inode, u32 new_clusters)
960 {
961         struct rb_node *free_head = NULL;
962         struct ocfs2_extent_map *em = &OCFS2_I(inode)->ip_map;
963         struct ocfs2_extent_map_entry *ent;
964
965         spin_lock(&OCFS2_I(inode)->ip_lock);
966
967         __ocfs2_extent_map_drop(inode, new_clusters, &free_head, &ent);
968
969         if (ent) {
970                 rb_erase(&ent->e_node, &em->em_extents);
971                 ent->e_node.rb_right = free_head;
972                 free_head = &ent->e_node;
973         }
974
975         spin_unlock(&OCFS2_I(inode)->ip_lock);
976
977         if (free_head)
978                 __ocfs2_extent_map_drop_cleanup(free_head);
979
980         return 0;
981 }
982
983 /*
984  * Remove all entries past new_clusters and also clip any extent
985  * straddling new_clusters, if there is one.  This does not check
986  * or modify ip_clusters
987  */
988 int ocfs2_extent_map_trunc(struct inode *inode, u32 new_clusters)
989 {
990         struct rb_node *free_head = NULL;
991         struct ocfs2_extent_map_entry *ent = NULL;
992
993         spin_lock(&OCFS2_I(inode)->ip_lock);
994
995         __ocfs2_extent_map_drop(inode, new_clusters, &free_head, &ent);
996
997         if (ent)
998                 ent->e_rec.e_clusters = cpu_to_le32(new_clusters -
999                                                le32_to_cpu(ent->e_rec.e_cpos));
1000
1001         OCFS2_I(inode)->ip_map.em_clusters = new_clusters;
1002
1003         spin_unlock(&OCFS2_I(inode)->ip_lock);
1004
1005         if (free_head)
1006                 __ocfs2_extent_map_drop_cleanup(free_head);
1007
1008         return 0;
1009 }
1010
1011 int __init init_ocfs2_extent_maps(void)
1012 {
1013         ocfs2_em_ent_cachep =
1014                 kmem_cache_create("ocfs2_em_ent",
1015                                   sizeof(struct ocfs2_extent_map_entry),
1016                                   0, SLAB_HWCACHE_ALIGN, NULL, NULL);
1017         if (!ocfs2_em_ent_cachep)
1018                 return -ENOMEM;
1019
1020         return 0;
1021 }
1022
1023 void exit_ocfs2_extent_maps(void)
1024 {
1025         kmem_cache_destroy(ocfs2_em_ent_cachep);
1026 }