fs: dcache scale dentry refcount
[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  * Block/Cluster mapping functions
7  *
8  * Copyright (C) 2004 Oracle.  All rights reserved.
9  *
10  * This program is free software; you can redistribute it and/or
11  * modify it under the terms of the GNU General Public
12  * License, version 2,  as published by the Free Software Foundation.
13  *
14  * This program is distributed in the hope that it will be useful,
15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
17  * General Public License for more details.
18  *
19  * You should have received a copy of the GNU General Public
20  * License along with this program; if not, write to the
21  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
22  * Boston, MA 021110-1307, USA.
23  */
24
25 #include <linux/fs.h>
26 #include <linux/init.h>
27 #include <linux/slab.h>
28 #include <linux/types.h>
29 #include <linux/fiemap.h>
30
31 #define MLOG_MASK_PREFIX ML_EXTENT_MAP
32 #include <cluster/masklog.h>
33
34 #include "ocfs2.h"
35
36 #include "alloc.h"
37 #include "dlmglue.h"
38 #include "extent_map.h"
39 #include "inode.h"
40 #include "super.h"
41 #include "symlink.h"
42
43 #include "buffer_head_io.h"
44
45 /*
46  * The extent caching implementation is intentionally trivial.
47  *
48  * We only cache a small number of extents stored directly on the
49  * inode, so linear order operations are acceptable. If we ever want
50  * to increase the size of the extent map, then these algorithms must
51  * get smarter.
52  */
53
54 void ocfs2_extent_map_init(struct inode *inode)
55 {
56         struct ocfs2_inode_info *oi = OCFS2_I(inode);
57
58         oi->ip_extent_map.em_num_items = 0;
59         INIT_LIST_HEAD(&oi->ip_extent_map.em_list);
60 }
61
62 static void __ocfs2_extent_map_lookup(struct ocfs2_extent_map *em,
63                                       unsigned int cpos,
64                                       struct ocfs2_extent_map_item **ret_emi)
65 {
66         unsigned int range;
67         struct ocfs2_extent_map_item *emi;
68
69         *ret_emi = NULL;
70
71         list_for_each_entry(emi, &em->em_list, ei_list) {
72                 range = emi->ei_cpos + emi->ei_clusters;
73
74                 if (cpos >= emi->ei_cpos && cpos < range) {
75                         list_move(&emi->ei_list, &em->em_list);
76
77                         *ret_emi = emi;
78                         break;
79                 }
80         }
81 }
82
83 static int ocfs2_extent_map_lookup(struct inode *inode, unsigned int cpos,
84                                    unsigned int *phys, unsigned int *len,
85                                    unsigned int *flags)
86 {
87         unsigned int coff;
88         struct ocfs2_inode_info *oi = OCFS2_I(inode);
89         struct ocfs2_extent_map_item *emi;
90
91         spin_lock(&oi->ip_lock);
92
93         __ocfs2_extent_map_lookup(&oi->ip_extent_map, cpos, &emi);
94         if (emi) {
95                 coff = cpos - emi->ei_cpos;
96                 *phys = emi->ei_phys + coff;
97                 if (len)
98                         *len = emi->ei_clusters - coff;
99                 if (flags)
100                         *flags = emi->ei_flags;
101         }
102
103         spin_unlock(&oi->ip_lock);
104
105         if (emi == NULL)
106                 return -ENOENT;
107
108         return 0;
109 }
110
111 /*
112  * Forget about all clusters equal to or greater than cpos.
113  */
114 void ocfs2_extent_map_trunc(struct inode *inode, unsigned int cpos)
115 {
116         struct ocfs2_extent_map_item *emi, *n;
117         struct ocfs2_inode_info *oi = OCFS2_I(inode);
118         struct ocfs2_extent_map *em = &oi->ip_extent_map;
119         LIST_HEAD(tmp_list);
120         unsigned int range;
121
122         spin_lock(&oi->ip_lock);
123         list_for_each_entry_safe(emi, n, &em->em_list, ei_list) {
124                 if (emi->ei_cpos >= cpos) {
125                         /* Full truncate of this record. */
126                         list_move(&emi->ei_list, &tmp_list);
127                         BUG_ON(em->em_num_items == 0);
128                         em->em_num_items--;
129                         continue;
130                 }
131
132                 range = emi->ei_cpos + emi->ei_clusters;
133                 if (range > cpos) {
134                         /* Partial truncate */
135                         emi->ei_clusters = cpos - emi->ei_cpos;
136                 }
137         }
138         spin_unlock(&oi->ip_lock);
139
140         list_for_each_entry_safe(emi, n, &tmp_list, ei_list) {
141                 list_del(&emi->ei_list);
142                 kfree(emi);
143         }
144 }
145
146 /*
147  * Is any part of emi2 contained within emi1
148  */
149 static int ocfs2_ei_is_contained(struct ocfs2_extent_map_item *emi1,
150                                  struct ocfs2_extent_map_item *emi2)
151 {
152         unsigned int range1, range2;
153
154         /*
155          * Check if logical start of emi2 is inside emi1
156          */
157         range1 = emi1->ei_cpos + emi1->ei_clusters;
158         if (emi2->ei_cpos >= emi1->ei_cpos && emi2->ei_cpos < range1)
159                 return 1;
160
161         /*
162          * Check if logical end of emi2 is inside emi1
163          */
164         range2 = emi2->ei_cpos + emi2->ei_clusters;
165         if (range2 > emi1->ei_cpos && range2 <= range1)
166                 return 1;
167
168         return 0;
169 }
170
171 static void ocfs2_copy_emi_fields(struct ocfs2_extent_map_item *dest,
172                                   struct ocfs2_extent_map_item *src)
173 {
174         dest->ei_cpos = src->ei_cpos;
175         dest->ei_phys = src->ei_phys;
176         dest->ei_clusters = src->ei_clusters;
177         dest->ei_flags = src->ei_flags;
178 }
179
180 /*
181  * Try to merge emi with ins. Returns 1 if merge succeeds, zero
182  * otherwise.
183  */
184 static int ocfs2_try_to_merge_extent_map(struct ocfs2_extent_map_item *emi,
185                                          struct ocfs2_extent_map_item *ins)
186 {
187         /*
188          * Handle contiguousness
189          */
190         if (ins->ei_phys == (emi->ei_phys + emi->ei_clusters) &&
191             ins->ei_cpos == (emi->ei_cpos + emi->ei_clusters) &&
192             ins->ei_flags == emi->ei_flags) {
193                 emi->ei_clusters += ins->ei_clusters;
194                 return 1;
195         } else if ((ins->ei_phys + ins->ei_clusters) == emi->ei_phys &&
196                    (ins->ei_cpos + ins->ei_clusters) == emi->ei_cpos &&
197                    ins->ei_flags == emi->ei_flags) {
198                 emi->ei_phys = ins->ei_phys;
199                 emi->ei_cpos = ins->ei_cpos;
200                 emi->ei_clusters += ins->ei_clusters;
201                 return 1;
202         }
203
204         /*
205          * Overlapping extents - this shouldn't happen unless we've
206          * split an extent to change it's flags. That is exceedingly
207          * rare, so there's no sense in trying to optimize it yet.
208          */
209         if (ocfs2_ei_is_contained(emi, ins) ||
210             ocfs2_ei_is_contained(ins, emi)) {
211                 ocfs2_copy_emi_fields(emi, ins);
212                 return 1;
213         }
214
215         /* No merge was possible. */
216         return 0;
217 }
218
219 /*
220  * In order to reduce complexity on the caller, this insert function
221  * is intentionally liberal in what it will accept.
222  *
223  * The only rule is that the truncate call *must* be used whenever
224  * records have been deleted. This avoids inserting overlapping
225  * records with different physical mappings.
226  */
227 void ocfs2_extent_map_insert_rec(struct inode *inode,
228                                  struct ocfs2_extent_rec *rec)
229 {
230         struct ocfs2_inode_info *oi = OCFS2_I(inode);
231         struct ocfs2_extent_map *em = &oi->ip_extent_map;
232         struct ocfs2_extent_map_item *emi, *new_emi = NULL;
233         struct ocfs2_extent_map_item ins;
234
235         ins.ei_cpos = le32_to_cpu(rec->e_cpos);
236         ins.ei_phys = ocfs2_blocks_to_clusters(inode->i_sb,
237                                                le64_to_cpu(rec->e_blkno));
238         ins.ei_clusters = le16_to_cpu(rec->e_leaf_clusters);
239         ins.ei_flags = rec->e_flags;
240
241 search:
242         spin_lock(&oi->ip_lock);
243
244         list_for_each_entry(emi, &em->em_list, ei_list) {
245                 if (ocfs2_try_to_merge_extent_map(emi, &ins)) {
246                         list_move(&emi->ei_list, &em->em_list);
247                         spin_unlock(&oi->ip_lock);
248                         goto out;
249                 }
250         }
251
252         /*
253          * No item could be merged.
254          *
255          * Either allocate and add a new item, or overwrite the last recently
256          * inserted.
257          */
258
259         if (em->em_num_items < OCFS2_MAX_EXTENT_MAP_ITEMS) {
260                 if (new_emi == NULL) {
261                         spin_unlock(&oi->ip_lock);
262
263                         new_emi = kmalloc(sizeof(*new_emi), GFP_NOFS);
264                         if (new_emi == NULL)
265                                 goto out;
266
267                         goto search;
268                 }
269
270                 ocfs2_copy_emi_fields(new_emi, &ins);
271                 list_add(&new_emi->ei_list, &em->em_list);
272                 em->em_num_items++;
273                 new_emi = NULL;
274         } else {
275                 BUG_ON(list_empty(&em->em_list) || em->em_num_items == 0);
276                 emi = list_entry(em->em_list.prev,
277                                  struct ocfs2_extent_map_item, ei_list);
278                 list_move(&emi->ei_list, &em->em_list);
279                 ocfs2_copy_emi_fields(emi, &ins);
280         }
281
282         spin_unlock(&oi->ip_lock);
283
284 out:
285         if (new_emi)
286                 kfree(new_emi);
287 }
288
289 static int ocfs2_last_eb_is_empty(struct inode *inode,
290                                   struct ocfs2_dinode *di)
291 {
292         int ret, next_free;
293         u64 last_eb_blk = le64_to_cpu(di->i_last_eb_blk);
294         struct buffer_head *eb_bh = NULL;
295         struct ocfs2_extent_block *eb;
296         struct ocfs2_extent_list *el;
297
298         ret = ocfs2_read_extent_block(INODE_CACHE(inode), last_eb_blk, &eb_bh);
299         if (ret) {
300                 mlog_errno(ret);
301                 goto out;
302         }
303
304         eb = (struct ocfs2_extent_block *) eb_bh->b_data;
305         el = &eb->h_list;
306
307         if (el->l_tree_depth) {
308                 ocfs2_error(inode->i_sb,
309                             "Inode %lu has non zero tree depth in "
310                             "leaf block %llu\n", inode->i_ino,
311                             (unsigned long long)eb_bh->b_blocknr);
312                 ret = -EROFS;
313                 goto out;
314         }
315
316         next_free = le16_to_cpu(el->l_next_free_rec);
317
318         if (next_free == 0 ||
319             (next_free == 1 && ocfs2_is_empty_extent(&el->l_recs[0])))
320                 ret = 1;
321
322 out:
323         brelse(eb_bh);
324         return ret;
325 }
326
327 /*
328  * Return the 1st index within el which contains an extent start
329  * larger than v_cluster.
330  */
331 static int ocfs2_search_for_hole_index(struct ocfs2_extent_list *el,
332                                        u32 v_cluster)
333 {
334         int i;
335         struct ocfs2_extent_rec *rec;
336
337         for(i = 0; i < le16_to_cpu(el->l_next_free_rec); i++) {
338                 rec = &el->l_recs[i];
339
340                 if (v_cluster < le32_to_cpu(rec->e_cpos))
341                         break;
342         }
343
344         return i;
345 }
346
347 /*
348  * Figure out the size of a hole which starts at v_cluster within the given
349  * extent list.
350  *
351  * If there is no more allocation past v_cluster, we return the maximum
352  * cluster size minus v_cluster.
353  *
354  * If we have in-inode extents, then el points to the dinode list and
355  * eb_bh is NULL. Otherwise, eb_bh should point to the extent block
356  * containing el.
357  */
358 int ocfs2_figure_hole_clusters(struct ocfs2_caching_info *ci,
359                                struct ocfs2_extent_list *el,
360                                struct buffer_head *eb_bh,
361                                u32 v_cluster,
362                                u32 *num_clusters)
363 {
364         int ret, i;
365         struct buffer_head *next_eb_bh = NULL;
366         struct ocfs2_extent_block *eb, *next_eb;
367
368         i = ocfs2_search_for_hole_index(el, v_cluster);
369
370         if (i == le16_to_cpu(el->l_next_free_rec) && eb_bh) {
371                 eb = (struct ocfs2_extent_block *)eb_bh->b_data;
372
373                 /*
374                  * Check the next leaf for any extents.
375                  */
376
377                 if (le64_to_cpu(eb->h_next_leaf_blk) == 0ULL)
378                         goto no_more_extents;
379
380                 ret = ocfs2_read_extent_block(ci,
381                                               le64_to_cpu(eb->h_next_leaf_blk),
382                                               &next_eb_bh);
383                 if (ret) {
384                         mlog_errno(ret);
385                         goto out;
386                 }
387
388                 next_eb = (struct ocfs2_extent_block *)next_eb_bh->b_data;
389                 el = &next_eb->h_list;
390                 i = ocfs2_search_for_hole_index(el, v_cluster);
391         }
392
393 no_more_extents:
394         if (i == le16_to_cpu(el->l_next_free_rec)) {
395                 /*
396                  * We're at the end of our existing allocation. Just
397                  * return the maximum number of clusters we could
398                  * possibly allocate.
399                  */
400                 *num_clusters = UINT_MAX - v_cluster;
401         } else {
402                 *num_clusters = le32_to_cpu(el->l_recs[i].e_cpos) - v_cluster;
403         }
404
405         ret = 0;
406 out:
407         brelse(next_eb_bh);
408         return ret;
409 }
410
411 static int ocfs2_get_clusters_nocache(struct inode *inode,
412                                       struct buffer_head *di_bh,
413                                       u32 v_cluster, unsigned int *hole_len,
414                                       struct ocfs2_extent_rec *ret_rec,
415                                       unsigned int *is_last)
416 {
417         int i, ret, tree_height, len;
418         struct ocfs2_dinode *di;
419         struct ocfs2_extent_block *uninitialized_var(eb);
420         struct ocfs2_extent_list *el;
421         struct ocfs2_extent_rec *rec;
422         struct buffer_head *eb_bh = NULL;
423
424         memset(ret_rec, 0, sizeof(*ret_rec));
425         if (is_last)
426                 *is_last = 0;
427
428         di = (struct ocfs2_dinode *) di_bh->b_data;
429         el = &di->id2.i_list;
430         tree_height = le16_to_cpu(el->l_tree_depth);
431
432         if (tree_height > 0) {
433                 ret = ocfs2_find_leaf(INODE_CACHE(inode), el, v_cluster,
434                                       &eb_bh);
435                 if (ret) {
436                         mlog_errno(ret);
437                         goto out;
438                 }
439
440                 eb = (struct ocfs2_extent_block *) eb_bh->b_data;
441                 el = &eb->h_list;
442
443                 if (el->l_tree_depth) {
444                         ocfs2_error(inode->i_sb,
445                                     "Inode %lu has non zero tree depth in "
446                                     "leaf block %llu\n", inode->i_ino,
447                                     (unsigned long long)eb_bh->b_blocknr);
448                         ret = -EROFS;
449                         goto out;
450                 }
451         }
452
453         i = ocfs2_search_extent_list(el, v_cluster);
454         if (i == -1) {
455                 /*
456                  * Holes can be larger than the maximum size of an
457                  * extent, so we return their lengths in a separate
458                  * field.
459                  */
460                 if (hole_len) {
461                         ret = ocfs2_figure_hole_clusters(INODE_CACHE(inode),
462                                                          el, eb_bh,
463                                                          v_cluster, &len);
464                         if (ret) {
465                                 mlog_errno(ret);
466                                 goto out;
467                         }
468
469                         *hole_len = len;
470                 }
471                 goto out_hole;
472         }
473
474         rec = &el->l_recs[i];
475
476         BUG_ON(v_cluster < le32_to_cpu(rec->e_cpos));
477
478         if (!rec->e_blkno) {
479                 ocfs2_error(inode->i_sb, "Inode %lu has bad extent "
480                             "record (%u, %u, 0)", inode->i_ino,
481                             le32_to_cpu(rec->e_cpos),
482                             ocfs2_rec_clusters(el, rec));
483                 ret = -EROFS;
484                 goto out;
485         }
486
487         *ret_rec = *rec;
488
489         /*
490          * Checking for last extent is potentially expensive - we
491          * might have to look at the next leaf over to see if it's
492          * empty.
493          *
494          * The first two checks are to see whether the caller even
495          * cares for this information, and if the extent is at least
496          * the last in it's list.
497          *
498          * If those hold true, then the extent is last if any of the
499          * additional conditions hold true:
500          *  - Extent list is in-inode
501          *  - Extent list is right-most
502          *  - Extent list is 2nd to rightmost, with empty right-most
503          */
504         if (is_last) {
505                 if (i == (le16_to_cpu(el->l_next_free_rec) - 1)) {
506                         if (tree_height == 0)
507                                 *is_last = 1;
508                         else if (eb->h_blkno == di->i_last_eb_blk)
509                                 *is_last = 1;
510                         else if (eb->h_next_leaf_blk == di->i_last_eb_blk) {
511                                 ret = ocfs2_last_eb_is_empty(inode, di);
512                                 if (ret < 0) {
513                                         mlog_errno(ret);
514                                         goto out;
515                                 }
516                                 if (ret == 1)
517                                         *is_last = 1;
518                         }
519                 }
520         }
521
522 out_hole:
523         ret = 0;
524 out:
525         brelse(eb_bh);
526         return ret;
527 }
528
529 static void ocfs2_relative_extent_offsets(struct super_block *sb,
530                                           u32 v_cluster,
531                                           struct ocfs2_extent_rec *rec,
532                                           u32 *p_cluster, u32 *num_clusters)
533
534 {
535         u32 coff = v_cluster - le32_to_cpu(rec->e_cpos);
536
537         *p_cluster = ocfs2_blocks_to_clusters(sb, le64_to_cpu(rec->e_blkno));
538         *p_cluster = *p_cluster + coff;
539
540         if (num_clusters)
541                 *num_clusters = le16_to_cpu(rec->e_leaf_clusters) - coff;
542 }
543
544 int ocfs2_xattr_get_clusters(struct inode *inode, u32 v_cluster,
545                              u32 *p_cluster, u32 *num_clusters,
546                              struct ocfs2_extent_list *el,
547                              unsigned int *extent_flags)
548 {
549         int ret = 0, i;
550         struct buffer_head *eb_bh = NULL;
551         struct ocfs2_extent_block *eb;
552         struct ocfs2_extent_rec *rec;
553         u32 coff;
554
555         if (el->l_tree_depth) {
556                 ret = ocfs2_find_leaf(INODE_CACHE(inode), el, v_cluster,
557                                       &eb_bh);
558                 if (ret) {
559                         mlog_errno(ret);
560                         goto out;
561                 }
562
563                 eb = (struct ocfs2_extent_block *) eb_bh->b_data;
564                 el = &eb->h_list;
565
566                 if (el->l_tree_depth) {
567                         ocfs2_error(inode->i_sb,
568                                     "Inode %lu has non zero tree depth in "
569                                     "xattr leaf block %llu\n", inode->i_ino,
570                                     (unsigned long long)eb_bh->b_blocknr);
571                         ret = -EROFS;
572                         goto out;
573                 }
574         }
575
576         i = ocfs2_search_extent_list(el, v_cluster);
577         if (i == -1) {
578                 ret = -EROFS;
579                 mlog_errno(ret);
580                 goto out;
581         } else {
582                 rec = &el->l_recs[i];
583                 BUG_ON(v_cluster < le32_to_cpu(rec->e_cpos));
584
585                 if (!rec->e_blkno) {
586                         ocfs2_error(inode->i_sb, "Inode %lu has bad extent "
587                                     "record (%u, %u, 0) in xattr", inode->i_ino,
588                                     le32_to_cpu(rec->e_cpos),
589                                     ocfs2_rec_clusters(el, rec));
590                         ret = -EROFS;
591                         goto out;
592                 }
593                 coff = v_cluster - le32_to_cpu(rec->e_cpos);
594                 *p_cluster = ocfs2_blocks_to_clusters(inode->i_sb,
595                                                     le64_to_cpu(rec->e_blkno));
596                 *p_cluster = *p_cluster + coff;
597                 if (num_clusters)
598                         *num_clusters = ocfs2_rec_clusters(el, rec) - coff;
599
600                 if (extent_flags)
601                         *extent_flags = rec->e_flags;
602         }
603 out:
604         if (eb_bh)
605                 brelse(eb_bh);
606         return ret;
607 }
608
609 int ocfs2_get_clusters(struct inode *inode, u32 v_cluster,
610                        u32 *p_cluster, u32 *num_clusters,
611                        unsigned int *extent_flags)
612 {
613         int ret;
614         unsigned int uninitialized_var(hole_len), flags = 0;
615         struct buffer_head *di_bh = NULL;
616         struct ocfs2_extent_rec rec;
617
618         if (OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL) {
619                 ret = -ERANGE;
620                 mlog_errno(ret);
621                 goto out;
622         }
623
624         ret = ocfs2_extent_map_lookup(inode, v_cluster, p_cluster,
625                                       num_clusters, extent_flags);
626         if (ret == 0)
627                 goto out;
628
629         ret = ocfs2_read_inode_block(inode, &di_bh);
630         if (ret) {
631                 mlog_errno(ret);
632                 goto out;
633         }
634
635         ret = ocfs2_get_clusters_nocache(inode, di_bh, v_cluster, &hole_len,
636                                          &rec, NULL);
637         if (ret) {
638                 mlog_errno(ret);
639                 goto out;
640         }
641
642         if (rec.e_blkno == 0ULL) {
643                 /*
644                  * A hole was found. Return some canned values that
645                  * callers can key on. If asked for, num_clusters will
646                  * be populated with the size of the hole.
647                  */
648                 *p_cluster = 0;
649                 if (num_clusters) {
650                         *num_clusters = hole_len;
651                 }
652         } else {
653                 ocfs2_relative_extent_offsets(inode->i_sb, v_cluster, &rec,
654                                               p_cluster, num_clusters);
655                 flags = rec.e_flags;
656
657                 ocfs2_extent_map_insert_rec(inode, &rec);
658         }
659
660         if (extent_flags)
661                 *extent_flags = flags;
662
663 out:
664         brelse(di_bh);
665         return ret;
666 }
667
668 /*
669  * This expects alloc_sem to be held. The allocation cannot change at
670  * all while the map is in the process of being updated.
671  */
672 int ocfs2_extent_map_get_blocks(struct inode *inode, u64 v_blkno, u64 *p_blkno,
673                                 u64 *ret_count, unsigned int *extent_flags)
674 {
675         int ret;
676         int bpc = ocfs2_clusters_to_blocks(inode->i_sb, 1);
677         u32 cpos, num_clusters, p_cluster;
678         u64 boff = 0;
679
680         cpos = ocfs2_blocks_to_clusters(inode->i_sb, v_blkno);
681
682         ret = ocfs2_get_clusters(inode, cpos, &p_cluster, &num_clusters,
683                                  extent_flags);
684         if (ret) {
685                 mlog_errno(ret);
686                 goto out;
687         }
688
689         /*
690          * p_cluster == 0 indicates a hole.
691          */
692         if (p_cluster) {
693                 boff = ocfs2_clusters_to_blocks(inode->i_sb, p_cluster);
694                 boff += (v_blkno & (u64)(bpc - 1));
695         }
696
697         *p_blkno = boff;
698
699         if (ret_count) {
700                 *ret_count = ocfs2_clusters_to_blocks(inode->i_sb, num_clusters);
701                 *ret_count -= v_blkno & (u64)(bpc - 1);
702         }
703
704 out:
705         return ret;
706 }
707
708 /*
709  * The ocfs2_fiemap_inline() may be a little bit misleading, since
710  * it not only handles the fiemap for inlined files, but also deals
711  * with the fast symlink, cause they have no difference for extent
712  * mapping per se.
713  */
714 static int ocfs2_fiemap_inline(struct inode *inode, struct buffer_head *di_bh,
715                                struct fiemap_extent_info *fieinfo,
716                                u64 map_start)
717 {
718         int ret;
719         unsigned int id_count;
720         struct ocfs2_dinode *di;
721         u64 phys;
722         u32 flags = FIEMAP_EXTENT_DATA_INLINE|FIEMAP_EXTENT_LAST;
723         struct ocfs2_inode_info *oi = OCFS2_I(inode);
724
725         di = (struct ocfs2_dinode *)di_bh->b_data;
726         if (ocfs2_inode_is_fast_symlink(inode))
727                 id_count = ocfs2_fast_symlink_chars(inode->i_sb);
728         else
729                 id_count = le16_to_cpu(di->id2.i_data.id_count);
730
731         if (map_start < id_count) {
732                 phys = oi->ip_blkno << inode->i_sb->s_blocksize_bits;
733                 if (ocfs2_inode_is_fast_symlink(inode))
734                         phys += offsetof(struct ocfs2_dinode, id2.i_symlink);
735                 else
736                         phys += offsetof(struct ocfs2_dinode,
737                                          id2.i_data.id_data);
738
739                 ret = fiemap_fill_next_extent(fieinfo, 0, phys, id_count,
740                                               flags);
741                 if (ret < 0)
742                         return ret;
743         }
744
745         return 0;
746 }
747
748 #define OCFS2_FIEMAP_FLAGS      (FIEMAP_FLAG_SYNC)
749
750 int ocfs2_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
751                  u64 map_start, u64 map_len)
752 {
753         int ret, is_last;
754         u32 mapping_end, cpos;
755         unsigned int hole_size;
756         struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
757         u64 len_bytes, phys_bytes, virt_bytes;
758         struct buffer_head *di_bh = NULL;
759         struct ocfs2_extent_rec rec;
760
761         ret = fiemap_check_flags(fieinfo, OCFS2_FIEMAP_FLAGS);
762         if (ret)
763                 return ret;
764
765         ret = ocfs2_inode_lock(inode, &di_bh, 0);
766         if (ret) {
767                 mlog_errno(ret);
768                 goto out;
769         }
770
771         down_read(&OCFS2_I(inode)->ip_alloc_sem);
772
773         /*
774          * Handle inline-data and fast symlink separately.
775          */
776         if ((OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL) ||
777             ocfs2_inode_is_fast_symlink(inode)) {
778                 ret = ocfs2_fiemap_inline(inode, di_bh, fieinfo, map_start);
779                 goto out_unlock;
780         }
781
782         cpos = map_start >> osb->s_clustersize_bits;
783         mapping_end = ocfs2_clusters_for_bytes(inode->i_sb,
784                                                map_start + map_len);
785         mapping_end -= cpos;
786         is_last = 0;
787         while (cpos < mapping_end && !is_last) {
788                 u32 fe_flags;
789
790                 ret = ocfs2_get_clusters_nocache(inode, di_bh, cpos,
791                                                  &hole_size, &rec, &is_last);
792                 if (ret) {
793                         mlog_errno(ret);
794                         goto out;
795                 }
796
797                 if (rec.e_blkno == 0ULL) {
798                         cpos += hole_size;
799                         continue;
800                 }
801
802                 fe_flags = 0;
803                 if (rec.e_flags & OCFS2_EXT_UNWRITTEN)
804                         fe_flags |= FIEMAP_EXTENT_UNWRITTEN;
805                 if (rec.e_flags & OCFS2_EXT_REFCOUNTED)
806                         fe_flags |= FIEMAP_EXTENT_SHARED;
807                 if (is_last)
808                         fe_flags |= FIEMAP_EXTENT_LAST;
809                 len_bytes = (u64)le16_to_cpu(rec.e_leaf_clusters) << osb->s_clustersize_bits;
810                 phys_bytes = le64_to_cpu(rec.e_blkno) << osb->sb->s_blocksize_bits;
811                 virt_bytes = (u64)le32_to_cpu(rec.e_cpos) << osb->s_clustersize_bits;
812
813                 ret = fiemap_fill_next_extent(fieinfo, virt_bytes, phys_bytes,
814                                               len_bytes, fe_flags);
815                 if (ret)
816                         break;
817
818                 cpos = le32_to_cpu(rec.e_cpos)+ le16_to_cpu(rec.e_leaf_clusters);
819         }
820
821         if (ret > 0)
822                 ret = 0;
823
824 out_unlock:
825         brelse(di_bh);
826
827         up_read(&OCFS2_I(inode)->ip_alloc_sem);
828
829         ocfs2_inode_unlock(inode, 0);
830 out:
831
832         return ret;
833 }
834
835 int ocfs2_read_virt_blocks(struct inode *inode, u64 v_block, int nr,
836                            struct buffer_head *bhs[], int flags,
837                            int (*validate)(struct super_block *sb,
838                                            struct buffer_head *bh))
839 {
840         int rc = 0;
841         u64 p_block, p_count;
842         int i, count, done = 0;
843
844         mlog_entry("(inode = %p, v_block = %llu, nr = %d, bhs = %p, "
845                    "flags = %x, validate = %p)\n",
846                    inode, (unsigned long long)v_block, nr, bhs, flags,
847                    validate);
848
849         if (((v_block + nr - 1) << inode->i_sb->s_blocksize_bits) >=
850             i_size_read(inode)) {
851                 BUG_ON(!(flags & OCFS2_BH_READAHEAD));
852                 goto out;
853         }
854
855         while (done < nr) {
856                 down_read(&OCFS2_I(inode)->ip_alloc_sem);
857                 rc = ocfs2_extent_map_get_blocks(inode, v_block + done,
858                                                  &p_block, &p_count, NULL);
859                 up_read(&OCFS2_I(inode)->ip_alloc_sem);
860                 if (rc) {
861                         mlog_errno(rc);
862                         break;
863                 }
864
865                 if (!p_block) {
866                         rc = -EIO;
867                         mlog(ML_ERROR,
868                              "Inode #%llu contains a hole at offset %llu\n",
869                              (unsigned long long)OCFS2_I(inode)->ip_blkno,
870                              (unsigned long long)(v_block + done) <<
871                              inode->i_sb->s_blocksize_bits);
872                         break;
873                 }
874
875                 count = nr - done;
876                 if (p_count < count)
877                         count = p_count;
878
879                 /*
880                  * If the caller passed us bhs, they should have come
881                  * from a previous readahead call to this function.  Thus,
882                  * they should have the right b_blocknr.
883                  */
884                 for (i = 0; i < count; i++) {
885                         if (!bhs[done + i])
886                                 continue;
887                         BUG_ON(bhs[done + i]->b_blocknr != (p_block + i));
888                 }
889
890                 rc = ocfs2_read_blocks(INODE_CACHE(inode), p_block, count,
891                                        bhs + done, flags, validate);
892                 if (rc) {
893                         mlog_errno(rc);
894                         break;
895                 }
896                 done += count;
897         }
898
899 out:
900         mlog_exit(rc);
901         return rc;
902 }
903
904