2487116d0d3312981834aa3667fd708dc7aa05ab
[linux-3.10.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 #include <cluster/masklog.h>
32
33 #include "ocfs2.h"
34
35 #include "alloc.h"
36 #include "dlmglue.h"
37 #include "extent_map.h"
38 #include "inode.h"
39 #include "super.h"
40 #include "symlink.h"
41 #include "ocfs2_trace.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         kfree(new_emi);
286 }
287
288 static int ocfs2_last_eb_is_empty(struct inode *inode,
289                                   struct ocfs2_dinode *di)
290 {
291         int ret, next_free;
292         u64 last_eb_blk = le64_to_cpu(di->i_last_eb_blk);
293         struct buffer_head *eb_bh = NULL;
294         struct ocfs2_extent_block *eb;
295         struct ocfs2_extent_list *el;
296
297         ret = ocfs2_read_extent_block(INODE_CACHE(inode), last_eb_blk, &eb_bh);
298         if (ret) {
299                 mlog_errno(ret);
300                 goto out;
301         }
302
303         eb = (struct ocfs2_extent_block *) eb_bh->b_data;
304         el = &eb->h_list;
305
306         if (el->l_tree_depth) {
307                 ocfs2_error(inode->i_sb,
308                             "Inode %lu has non zero tree depth in "
309                             "leaf block %llu\n", inode->i_ino,
310                             (unsigned long long)eb_bh->b_blocknr);
311                 ret = -EROFS;
312                 goto out;
313         }
314
315         next_free = le16_to_cpu(el->l_next_free_rec);
316
317         if (next_free == 0 ||
318             (next_free == 1 && ocfs2_is_empty_extent(&el->l_recs[0])))
319                 ret = 1;
320
321 out:
322         brelse(eb_bh);
323         return ret;
324 }
325
326 /*
327  * Return the 1st index within el which contains an extent start
328  * larger than v_cluster.
329  */
330 static int ocfs2_search_for_hole_index(struct ocfs2_extent_list *el,
331                                        u32 v_cluster)
332 {
333         int i;
334         struct ocfs2_extent_rec *rec;
335
336         for(i = 0; i < le16_to_cpu(el->l_next_free_rec); i++) {
337                 rec = &el->l_recs[i];
338
339                 if (v_cluster < le32_to_cpu(rec->e_cpos))
340                         break;
341         }
342
343         return i;
344 }
345
346 /*
347  * Figure out the size of a hole which starts at v_cluster within the given
348  * extent list.
349  *
350  * If there is no more allocation past v_cluster, we return the maximum
351  * cluster size minus v_cluster.
352  *
353  * If we have in-inode extents, then el points to the dinode list and
354  * eb_bh is NULL. Otherwise, eb_bh should point to the extent block
355  * containing el.
356  */
357 int ocfs2_figure_hole_clusters(struct ocfs2_caching_info *ci,
358                                struct ocfs2_extent_list *el,
359                                struct buffer_head *eb_bh,
360                                u32 v_cluster,
361                                u32 *num_clusters)
362 {
363         int ret, i;
364         struct buffer_head *next_eb_bh = NULL;
365         struct ocfs2_extent_block *eb, *next_eb;
366
367         i = ocfs2_search_for_hole_index(el, v_cluster);
368
369         if (i == le16_to_cpu(el->l_next_free_rec) && eb_bh) {
370                 eb = (struct ocfs2_extent_block *)eb_bh->b_data;
371
372                 /*
373                  * Check the next leaf for any extents.
374                  */
375
376                 if (le64_to_cpu(eb->h_next_leaf_blk) == 0ULL)
377                         goto no_more_extents;
378
379                 ret = ocfs2_read_extent_block(ci,
380                                               le64_to_cpu(eb->h_next_leaf_blk),
381                                               &next_eb_bh);
382                 if (ret) {
383                         mlog_errno(ret);
384                         goto out;
385                 }
386
387                 next_eb = (struct ocfs2_extent_block *)next_eb_bh->b_data;
388                 el = &next_eb->h_list;
389                 i = ocfs2_search_for_hole_index(el, v_cluster);
390         }
391
392 no_more_extents:
393         if (i == le16_to_cpu(el->l_next_free_rec)) {
394                 /*
395                  * We're at the end of our existing allocation. Just
396                  * return the maximum number of clusters we could
397                  * possibly allocate.
398                  */
399                 *num_clusters = UINT_MAX - v_cluster;
400         } else {
401                 *num_clusters = le32_to_cpu(el->l_recs[i].e_cpos) - v_cluster;
402         }
403
404         ret = 0;
405 out:
406         brelse(next_eb_bh);
407         return ret;
408 }
409
410 static int ocfs2_get_clusters_nocache(struct inode *inode,
411                                       struct buffer_head *di_bh,
412                                       u32 v_cluster, unsigned int *hole_len,
413                                       struct ocfs2_extent_rec *ret_rec,
414                                       unsigned int *is_last)
415 {
416         int i, ret, tree_height, len;
417         struct ocfs2_dinode *di;
418         struct ocfs2_extent_block *uninitialized_var(eb);
419         struct ocfs2_extent_list *el;
420         struct ocfs2_extent_rec *rec;
421         struct buffer_head *eb_bh = NULL;
422
423         memset(ret_rec, 0, sizeof(*ret_rec));
424         if (is_last)
425                 *is_last = 0;
426
427         di = (struct ocfs2_dinode *) di_bh->b_data;
428         el = &di->id2.i_list;
429         tree_height = le16_to_cpu(el->l_tree_depth);
430
431         if (tree_height > 0) {
432                 ret = ocfs2_find_leaf(INODE_CACHE(inode), el, v_cluster,
433                                       &eb_bh);
434                 if (ret) {
435                         mlog_errno(ret);
436                         goto out;
437                 }
438
439                 eb = (struct ocfs2_extent_block *) eb_bh->b_data;
440                 el = &eb->h_list;
441
442                 if (el->l_tree_depth) {
443                         ocfs2_error(inode->i_sb,
444                                     "Inode %lu has non zero tree depth in "
445                                     "leaf block %llu\n", inode->i_ino,
446                                     (unsigned long long)eb_bh->b_blocknr);
447                         ret = -EROFS;
448                         goto out;
449                 }
450         }
451
452         i = ocfs2_search_extent_list(el, v_cluster);
453         if (i == -1) {
454                 /*
455                  * Holes can be larger than the maximum size of an
456                  * extent, so we return their lengths in a separate
457                  * field.
458                  */
459                 if (hole_len) {
460                         ret = ocfs2_figure_hole_clusters(INODE_CACHE(inode),
461                                                          el, eb_bh,
462                                                          v_cluster, &len);
463                         if (ret) {
464                                 mlog_errno(ret);
465                                 goto out;
466                         }
467
468                         *hole_len = len;
469                 }
470                 goto out_hole;
471         }
472
473         rec = &el->l_recs[i];
474
475         BUG_ON(v_cluster < le32_to_cpu(rec->e_cpos));
476
477         if (!rec->e_blkno) {
478                 ocfs2_error(inode->i_sb, "Inode %lu has bad extent "
479                             "record (%u, %u, 0)", inode->i_ino,
480                             le32_to_cpu(rec->e_cpos),
481                             ocfs2_rec_clusters(el, rec));
482                 ret = -EROFS;
483                 goto out;
484         }
485
486         *ret_rec = *rec;
487
488         /*
489          * Checking for last extent is potentially expensive - we
490          * might have to look at the next leaf over to see if it's
491          * empty.
492          *
493          * The first two checks are to see whether the caller even
494          * cares for this information, and if the extent is at least
495          * the last in it's list.
496          *
497          * If those hold true, then the extent is last if any of the
498          * additional conditions hold true:
499          *  - Extent list is in-inode
500          *  - Extent list is right-most
501          *  - Extent list is 2nd to rightmost, with empty right-most
502          */
503         if (is_last) {
504                 if (i == (le16_to_cpu(el->l_next_free_rec) - 1)) {
505                         if (tree_height == 0)
506                                 *is_last = 1;
507                         else if (eb->h_blkno == di->i_last_eb_blk)
508                                 *is_last = 1;
509                         else if (eb->h_next_leaf_blk == di->i_last_eb_blk) {
510                                 ret = ocfs2_last_eb_is_empty(inode, di);
511                                 if (ret < 0) {
512                                         mlog_errno(ret);
513                                         goto out;
514                                 }
515                                 if (ret == 1)
516                                         *is_last = 1;
517                         }
518                 }
519         }
520
521 out_hole:
522         ret = 0;
523 out:
524         brelse(eb_bh);
525         return ret;
526 }
527
528 static void ocfs2_relative_extent_offsets(struct super_block *sb,
529                                           u32 v_cluster,
530                                           struct ocfs2_extent_rec *rec,
531                                           u32 *p_cluster, u32 *num_clusters)
532
533 {
534         u32 coff = v_cluster - le32_to_cpu(rec->e_cpos);
535
536         *p_cluster = ocfs2_blocks_to_clusters(sb, le64_to_cpu(rec->e_blkno));
537         *p_cluster = *p_cluster + coff;
538
539         if (num_clusters)
540                 *num_clusters = le16_to_cpu(rec->e_leaf_clusters) - coff;
541 }
542
543 int ocfs2_xattr_get_clusters(struct inode *inode, u32 v_cluster,
544                              u32 *p_cluster, u32 *num_clusters,
545                              struct ocfs2_extent_list *el,
546                              unsigned int *extent_flags)
547 {
548         int ret = 0, i;
549         struct buffer_head *eb_bh = NULL;
550         struct ocfs2_extent_block *eb;
551         struct ocfs2_extent_rec *rec;
552         u32 coff;
553
554         if (el->l_tree_depth) {
555                 ret = ocfs2_find_leaf(INODE_CACHE(inode), el, v_cluster,
556                                       &eb_bh);
557                 if (ret) {
558                         mlog_errno(ret);
559                         goto out;
560                 }
561
562                 eb = (struct ocfs2_extent_block *) eb_bh->b_data;
563                 el = &eb->h_list;
564
565                 if (el->l_tree_depth) {
566                         ocfs2_error(inode->i_sb,
567                                     "Inode %lu has non zero tree depth in "
568                                     "xattr leaf block %llu\n", inode->i_ino,
569                                     (unsigned long long)eb_bh->b_blocknr);
570                         ret = -EROFS;
571                         goto out;
572                 }
573         }
574
575         i = ocfs2_search_extent_list(el, v_cluster);
576         if (i == -1) {
577                 ret = -EROFS;
578                 mlog_errno(ret);
579                 goto out;
580         } else {
581                 rec = &el->l_recs[i];
582                 BUG_ON(v_cluster < le32_to_cpu(rec->e_cpos));
583
584                 if (!rec->e_blkno) {
585                         ocfs2_error(inode->i_sb, "Inode %lu has bad extent "
586                                     "record (%u, %u, 0) in xattr", inode->i_ino,
587                                     le32_to_cpu(rec->e_cpos),
588                                     ocfs2_rec_clusters(el, rec));
589                         ret = -EROFS;
590                         goto out;
591                 }
592                 coff = v_cluster - le32_to_cpu(rec->e_cpos);
593                 *p_cluster = ocfs2_blocks_to_clusters(inode->i_sb,
594                                                     le64_to_cpu(rec->e_blkno));
595                 *p_cluster = *p_cluster + coff;
596                 if (num_clusters)
597                         *num_clusters = ocfs2_rec_clusters(el, rec) - coff;
598
599                 if (extent_flags)
600                         *extent_flags = rec->e_flags;
601         }
602 out:
603         if (eb_bh)
604                 brelse(eb_bh);
605         return ret;
606 }
607
608 int ocfs2_get_clusters(struct inode *inode, u32 v_cluster,
609                        u32 *p_cluster, u32 *num_clusters,
610                        unsigned int *extent_flags)
611 {
612         int ret;
613         unsigned int uninitialized_var(hole_len), flags = 0;
614         struct buffer_head *di_bh = NULL;
615         struct ocfs2_extent_rec rec;
616
617         if (OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL) {
618                 ret = -ERANGE;
619                 mlog_errno(ret);
620                 goto out;
621         }
622
623         ret = ocfs2_extent_map_lookup(inode, v_cluster, p_cluster,
624                                       num_clusters, extent_flags);
625         if (ret == 0)
626                 goto out;
627
628         ret = ocfs2_read_inode_block(inode, &di_bh);
629         if (ret) {
630                 mlog_errno(ret);
631                 goto out;
632         }
633
634         ret = ocfs2_get_clusters_nocache(inode, di_bh, v_cluster, &hole_len,
635                                          &rec, NULL);
636         if (ret) {
637                 mlog_errno(ret);
638                 goto out;
639         }
640
641         if (rec.e_blkno == 0ULL) {
642                 /*
643                  * A hole was found. Return some canned values that
644                  * callers can key on. If asked for, num_clusters will
645                  * be populated with the size of the hole.
646                  */
647                 *p_cluster = 0;
648                 if (num_clusters) {
649                         *num_clusters = hole_len;
650                 }
651         } else {
652                 ocfs2_relative_extent_offsets(inode->i_sb, v_cluster, &rec,
653                                               p_cluster, num_clusters);
654                 flags = rec.e_flags;
655
656                 ocfs2_extent_map_insert_rec(inode, &rec);
657         }
658
659         if (extent_flags)
660                 *extent_flags = flags;
661
662 out:
663         brelse(di_bh);
664         return ret;
665 }
666
667 /*
668  * This expects alloc_sem to be held. The allocation cannot change at
669  * all while the map is in the process of being updated.
670  */
671 int ocfs2_extent_map_get_blocks(struct inode *inode, u64 v_blkno, u64 *p_blkno,
672                                 u64 *ret_count, unsigned int *extent_flags)
673 {
674         int ret;
675         int bpc = ocfs2_clusters_to_blocks(inode->i_sb, 1);
676         u32 cpos, num_clusters, p_cluster;
677         u64 boff = 0;
678
679         cpos = ocfs2_blocks_to_clusters(inode->i_sb, v_blkno);
680
681         ret = ocfs2_get_clusters(inode, cpos, &p_cluster, &num_clusters,
682                                  extent_flags);
683         if (ret) {
684                 mlog_errno(ret);
685                 goto out;
686         }
687
688         /*
689          * p_cluster == 0 indicates a hole.
690          */
691         if (p_cluster) {
692                 boff = ocfs2_clusters_to_blocks(inode->i_sb, p_cluster);
693                 boff += (v_blkno & (u64)(bpc - 1));
694         }
695
696         *p_blkno = boff;
697
698         if (ret_count) {
699                 *ret_count = ocfs2_clusters_to_blocks(inode->i_sb, num_clusters);
700                 *ret_count -= v_blkno & (u64)(bpc - 1);
701         }
702
703 out:
704         return ret;
705 }
706
707 /*
708  * The ocfs2_fiemap_inline() may be a little bit misleading, since
709  * it not only handles the fiemap for inlined files, but also deals
710  * with the fast symlink, cause they have no difference for extent
711  * mapping per se.
712  */
713 static int ocfs2_fiemap_inline(struct inode *inode, struct buffer_head *di_bh,
714                                struct fiemap_extent_info *fieinfo,
715                                u64 map_start)
716 {
717         int ret;
718         unsigned int id_count;
719         struct ocfs2_dinode *di;
720         u64 phys;
721         u32 flags = FIEMAP_EXTENT_DATA_INLINE|FIEMAP_EXTENT_LAST;
722         struct ocfs2_inode_info *oi = OCFS2_I(inode);
723
724         di = (struct ocfs2_dinode *)di_bh->b_data;
725         if (ocfs2_inode_is_fast_symlink(inode))
726                 id_count = ocfs2_fast_symlink_chars(inode->i_sb);
727         else
728                 id_count = le16_to_cpu(di->id2.i_data.id_count);
729
730         if (map_start < id_count) {
731                 phys = oi->ip_blkno << inode->i_sb->s_blocksize_bits;
732                 if (ocfs2_inode_is_fast_symlink(inode))
733                         phys += offsetof(struct ocfs2_dinode, id2.i_symlink);
734                 else
735                         phys += offsetof(struct ocfs2_dinode,
736                                          id2.i_data.id_data);
737
738                 ret = fiemap_fill_next_extent(fieinfo, 0, phys, id_count,
739                                               flags);
740                 if (ret < 0)
741                         return ret;
742         }
743
744         return 0;
745 }
746
747 #define OCFS2_FIEMAP_FLAGS      (FIEMAP_FLAG_SYNC)
748
749 int ocfs2_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
750                  u64 map_start, u64 map_len)
751 {
752         int ret, is_last;
753         u32 mapping_end, cpos;
754         unsigned int hole_size;
755         struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
756         u64 len_bytes, phys_bytes, virt_bytes;
757         struct buffer_head *di_bh = NULL;
758         struct ocfs2_extent_rec rec;
759
760         ret = fiemap_check_flags(fieinfo, OCFS2_FIEMAP_FLAGS);
761         if (ret)
762                 return ret;
763
764         ret = ocfs2_inode_lock(inode, &di_bh, 0);
765         if (ret) {
766                 mlog_errno(ret);
767                 goto out;
768         }
769
770         down_read(&OCFS2_I(inode)->ip_alloc_sem);
771
772         /*
773          * Handle inline-data and fast symlink separately.
774          */
775         if ((OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL) ||
776             ocfs2_inode_is_fast_symlink(inode)) {
777                 ret = ocfs2_fiemap_inline(inode, di_bh, fieinfo, map_start);
778                 goto out_unlock;
779         }
780
781         cpos = map_start >> osb->s_clustersize_bits;
782         mapping_end = ocfs2_clusters_for_bytes(inode->i_sb,
783                                                map_start + map_len);
784         mapping_end -= cpos;
785         is_last = 0;
786         while (cpos < mapping_end && !is_last) {
787                 u32 fe_flags;
788
789                 ret = ocfs2_get_clusters_nocache(inode, di_bh, cpos,
790                                                  &hole_size, &rec, &is_last);
791                 if (ret) {
792                         mlog_errno(ret);
793                         goto out_unlock;
794                 }
795
796                 if (rec.e_blkno == 0ULL) {
797                         cpos += hole_size;
798                         continue;
799                 }
800
801                 fe_flags = 0;
802                 if (rec.e_flags & OCFS2_EXT_UNWRITTEN)
803                         fe_flags |= FIEMAP_EXTENT_UNWRITTEN;
804                 if (rec.e_flags & OCFS2_EXT_REFCOUNTED)
805                         fe_flags |= FIEMAP_EXTENT_SHARED;
806                 if (is_last)
807                         fe_flags |= FIEMAP_EXTENT_LAST;
808                 len_bytes = (u64)le16_to_cpu(rec.e_leaf_clusters) << osb->s_clustersize_bits;
809                 phys_bytes = le64_to_cpu(rec.e_blkno) << osb->sb->s_blocksize_bits;
810                 virt_bytes = (u64)le32_to_cpu(rec.e_cpos) << osb->s_clustersize_bits;
811
812                 ret = fiemap_fill_next_extent(fieinfo, virt_bytes, phys_bytes,
813                                               len_bytes, fe_flags);
814                 if (ret)
815                         break;
816
817                 cpos = le32_to_cpu(rec.e_cpos)+ le16_to_cpu(rec.e_leaf_clusters);
818         }
819
820         if (ret > 0)
821                 ret = 0;
822
823 out_unlock:
824         brelse(di_bh);
825
826         up_read(&OCFS2_I(inode)->ip_alloc_sem);
827
828         ocfs2_inode_unlock(inode, 0);
829 out:
830
831         return ret;
832 }
833
834 int ocfs2_seek_data_hole_offset(struct file *file, loff_t *offset, int whence)
835 {
836         struct inode *inode = file->f_mapping->host;
837         int ret;
838         unsigned int is_last = 0, is_data = 0;
839         u16 cs_bits = OCFS2_SB(inode->i_sb)->s_clustersize_bits;
840         u32 cpos, cend, clen, hole_size;
841         u64 extoff, extlen;
842         struct buffer_head *di_bh = NULL;
843         struct ocfs2_extent_rec rec;
844
845         BUG_ON(whence != SEEK_DATA && whence != SEEK_HOLE);
846
847         ret = ocfs2_inode_lock(inode, &di_bh, 0);
848         if (ret) {
849                 mlog_errno(ret);
850                 goto out;
851         }
852
853         down_read(&OCFS2_I(inode)->ip_alloc_sem);
854
855         if (*offset >= inode->i_size) {
856                 ret = -ENXIO;
857                 goto out_unlock;
858         }
859
860         if (OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL) {
861                 if (whence == SEEK_HOLE)
862                         *offset = inode->i_size;
863                 goto out_unlock;
864         }
865
866         clen = 0;
867         cpos = *offset >> cs_bits;
868         cend = ocfs2_clusters_for_bytes(inode->i_sb, inode->i_size);
869
870         while (cpos < cend && !is_last) {
871                 ret = ocfs2_get_clusters_nocache(inode, di_bh, cpos, &hole_size,
872                                                  &rec, &is_last);
873                 if (ret) {
874                         mlog_errno(ret);
875                         goto out_unlock;
876                 }
877
878                 extoff = cpos;
879                 extoff <<= cs_bits;
880
881                 if (rec.e_blkno == 0ULL) {
882                         clen = hole_size;
883                         is_data = 0;
884                 } else {
885                         clen = le16_to_cpu(rec.e_leaf_clusters) -
886                                 (cpos - le32_to_cpu(rec.e_cpos));
887                         is_data = (rec.e_flags & OCFS2_EXT_UNWRITTEN) ?  0 : 1;
888                 }
889
890                 if ((!is_data && whence == SEEK_HOLE) ||
891                     (is_data && whence == SEEK_DATA)) {
892                         if (extoff > *offset)
893                                 *offset = extoff;
894                         goto out_unlock;
895                 }
896
897                 if (!is_last)
898                         cpos += clen;
899         }
900
901         if (whence == SEEK_HOLE) {
902                 extoff = cpos;
903                 extoff <<= cs_bits;
904                 extlen = clen;
905                 extlen <<=  cs_bits;
906
907                 if ((extoff + extlen) > inode->i_size)
908                         extlen = inode->i_size - extoff;
909                 extoff += extlen;
910                 if (extoff > *offset)
911                         *offset = extoff;
912                 goto out_unlock;
913         }
914
915         ret = -ENXIO;
916
917 out_unlock:
918
919         brelse(di_bh);
920
921         up_read(&OCFS2_I(inode)->ip_alloc_sem);
922
923         ocfs2_inode_unlock(inode, 0);
924 out:
925         return ret;
926 }
927
928 int ocfs2_read_virt_blocks(struct inode *inode, u64 v_block, int nr,
929                            struct buffer_head *bhs[], int flags,
930                            int (*validate)(struct super_block *sb,
931                                            struct buffer_head *bh))
932 {
933         int rc = 0;
934         u64 p_block, p_count;
935         int i, count, done = 0;
936
937         trace_ocfs2_read_virt_blocks(
938              inode, (unsigned long long)v_block, nr, bhs, flags,
939              validate);
940
941         if (((v_block + nr - 1) << inode->i_sb->s_blocksize_bits) >=
942             i_size_read(inode)) {
943                 BUG_ON(!(flags & OCFS2_BH_READAHEAD));
944                 goto out;
945         }
946
947         while (done < nr) {
948                 down_read(&OCFS2_I(inode)->ip_alloc_sem);
949                 rc = ocfs2_extent_map_get_blocks(inode, v_block + done,
950                                                  &p_block, &p_count, NULL);
951                 up_read(&OCFS2_I(inode)->ip_alloc_sem);
952                 if (rc) {
953                         mlog_errno(rc);
954                         break;
955                 }
956
957                 if (!p_block) {
958                         rc = -EIO;
959                         mlog(ML_ERROR,
960                              "Inode #%llu contains a hole at offset %llu\n",
961                              (unsigned long long)OCFS2_I(inode)->ip_blkno,
962                              (unsigned long long)(v_block + done) <<
963                              inode->i_sb->s_blocksize_bits);
964                         break;
965                 }
966
967                 count = nr - done;
968                 if (p_count < count)
969                         count = p_count;
970
971                 /*
972                  * If the caller passed us bhs, they should have come
973                  * from a previous readahead call to this function.  Thus,
974                  * they should have the right b_blocknr.
975                  */
976                 for (i = 0; i < count; i++) {
977                         if (!bhs[done + i])
978                                 continue;
979                         BUG_ON(bhs[done + i]->b_blocknr != (p_block + i));
980                 }
981
982                 rc = ocfs2_read_blocks(INODE_CACHE(inode), p_block, count,
983                                        bhs + done, flags, validate);
984                 if (rc) {
985                         mlog_errno(rc);
986                         break;
987                 }
988                 done += count;
989         }
990
991 out:
992         return rc;
993 }
994
995