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TOMOYO Linux Cross Reference
Linux/fs/ocfs2/extent_map.c

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  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 leaf block %llu\n",
309                             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 leaf block %llu\n",
445                                     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,
479                             "Inode %lu has bad extent record (%u, %u, 0)\n",
480                             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 xattr leaf block %llu\n",
569                                     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,
587                                     "Inode %lu has bad extent record (%u, %u, 0) in xattr\n",
588                                     inode->i_ino,
589                                     le32_to_cpu(rec->e_cpos),
590                                     ocfs2_rec_clusters(el, rec));
591                         ret = -EROFS;
592                         goto out;
593                 }
594                 coff = v_cluster - le32_to_cpu(rec->e_cpos);
595                 *p_cluster = ocfs2_blocks_to_clusters(inode->i_sb,
596                                                     le64_to_cpu(rec->e_blkno));
597                 *p_cluster = *p_cluster + coff;
598                 if (num_clusters)
599                         *num_clusters = ocfs2_rec_clusters(el, rec) - coff;
600 
601                 if (extent_flags)
602                         *extent_flags = rec->e_flags;
603         }
604 out:
605         if (eb_bh)
606                 brelse(eb_bh);
607         return ret;
608 }
609 
610 int ocfs2_get_clusters(struct inode *inode, u32 v_cluster,
611                        u32 *p_cluster, u32 *num_clusters,
612                        unsigned int *extent_flags)
613 {
614         int ret;
615         unsigned int uninitialized_var(hole_len), flags = 0;
616         struct buffer_head *di_bh = NULL;
617         struct ocfs2_extent_rec rec;
618 
619         if (OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL) {
620                 ret = -ERANGE;
621                 mlog_errno(ret);
622                 goto out;
623         }
624 
625         ret = ocfs2_extent_map_lookup(inode, v_cluster, p_cluster,
626                                       num_clusters, extent_flags);
627         if (ret == 0)
628                 goto out;
629 
630         ret = ocfs2_read_inode_block(inode, &di_bh);
631         if (ret) {
632                 mlog_errno(ret);
633                 goto out;
634         }
635 
636         ret = ocfs2_get_clusters_nocache(inode, di_bh, v_cluster, &hole_len,
637                                          &rec, NULL);
638         if (ret) {
639                 mlog_errno(ret);
640                 goto out;
641         }
642 
643         if (rec.e_blkno == 0ULL) {
644                 /*
645                  * A hole was found. Return some canned values that
646                  * callers can key on. If asked for, num_clusters will
647                  * be populated with the size of the hole.
648                  */
649                 *p_cluster = 0;
650                 if (num_clusters) {
651                         *num_clusters = hole_len;
652                 }
653         } else {
654                 ocfs2_relative_extent_offsets(inode->i_sb, v_cluster, &rec,
655                                               p_cluster, num_clusters);
656                 flags = rec.e_flags;
657 
658                 ocfs2_extent_map_insert_rec(inode, &rec);
659         }
660 
661         if (extent_flags)
662                 *extent_flags = flags;
663 
664 out:
665         brelse(di_bh);
666         return ret;
667 }
668 
669 /*
670  * This expects alloc_sem to be held. The allocation cannot change at
671  * all while the map is in the process of being updated.
672  */
673 int ocfs2_extent_map_get_blocks(struct inode *inode, u64 v_blkno, u64 *p_blkno,
674                                 u64 *ret_count, unsigned int *extent_flags)
675 {
676         int ret;
677         int bpc = ocfs2_clusters_to_blocks(inode->i_sb, 1);
678         u32 cpos, num_clusters, p_cluster;
679         u64 boff = 0;
680 
681         cpos = ocfs2_blocks_to_clusters(inode->i_sb, v_blkno);
682 
683         ret = ocfs2_get_clusters(inode, cpos, &p_cluster, &num_clusters,
684                                  extent_flags);
685         if (ret) {
686                 mlog_errno(ret);
687                 goto out;
688         }
689 
690         /*
691          * p_cluster == 0 indicates a hole.
692          */
693         if (p_cluster) {
694                 boff = ocfs2_clusters_to_blocks(inode->i_sb, p_cluster);
695                 boff += (v_blkno & (u64)(bpc - 1));
696         }
697 
698         *p_blkno = boff;
699 
700         if (ret_count) {
701                 *ret_count = ocfs2_clusters_to_blocks(inode->i_sb, num_clusters);
702                 *ret_count -= v_blkno & (u64)(bpc - 1);
703         }
704 
705 out:
706         return ret;
707 }
708 
709 /*
710  * The ocfs2_fiemap_inline() may be a little bit misleading, since
711  * it not only handles the fiemap for inlined files, but also deals
712  * with the fast symlink, cause they have no difference for extent
713  * mapping per se.
714  */
715 static int ocfs2_fiemap_inline(struct inode *inode, struct buffer_head *di_bh,
716                                struct fiemap_extent_info *fieinfo,
717                                u64 map_start)
718 {
719         int ret;
720         unsigned int id_count;
721         struct ocfs2_dinode *di;
722         u64 phys;
723         u32 flags = FIEMAP_EXTENT_DATA_INLINE|FIEMAP_EXTENT_LAST;
724         struct ocfs2_inode_info *oi = OCFS2_I(inode);
725 
726         di = (struct ocfs2_dinode *)di_bh->b_data;
727         if (ocfs2_inode_is_fast_symlink(inode))
728                 id_count = ocfs2_fast_symlink_chars(inode->i_sb);
729         else
730                 id_count = le16_to_cpu(di->id2.i_data.id_count);
731 
732         if (map_start < id_count) {
733                 phys = oi->ip_blkno << inode->i_sb->s_blocksize_bits;
734                 if (ocfs2_inode_is_fast_symlink(inode))
735                         phys += offsetof(struct ocfs2_dinode, id2.i_symlink);
736                 else
737                         phys += offsetof(struct ocfs2_dinode,
738                                          id2.i_data.id_data);
739 
740                 ret = fiemap_fill_next_extent(fieinfo, 0, phys, id_count,
741                                               flags);
742                 if (ret < 0)
743                         return ret;
744         }
745 
746         return 0;
747 }
748 
749 #define OCFS2_FIEMAP_FLAGS      (FIEMAP_FLAG_SYNC)
750 
751 int ocfs2_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
752                  u64 map_start, u64 map_len)
753 {
754         int ret, is_last;
755         u32 mapping_end, cpos;
756         unsigned int hole_size;
757         struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
758         u64 len_bytes, phys_bytes, virt_bytes;
759         struct buffer_head *di_bh = NULL;
760         struct ocfs2_extent_rec rec;
761 
762         ret = fiemap_check_flags(fieinfo, OCFS2_FIEMAP_FLAGS);
763         if (ret)
764                 return ret;
765 
766         ret = ocfs2_inode_lock(inode, &di_bh, 0);
767         if (ret) {
768                 mlog_errno(ret);
769                 goto out;
770         }
771 
772         down_read(&OCFS2_I(inode)->ip_alloc_sem);
773 
774         /*
775          * Handle inline-data and fast symlink separately.
776          */
777         if ((OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL) ||
778             ocfs2_inode_is_fast_symlink(inode)) {
779                 ret = ocfs2_fiemap_inline(inode, di_bh, fieinfo, map_start);
780                 goto out_unlock;
781         }
782 
783         cpos = map_start >> osb->s_clustersize_bits;
784         mapping_end = ocfs2_clusters_for_bytes(inode->i_sb,
785                                                map_start + map_len);
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_unlock;
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_seek_data_hole_offset(struct file *file, loff_t *offset, int whence)
836 {
837         struct inode *inode = file->f_mapping->host;
838         int ret;
839         unsigned int is_last = 0, is_data = 0;
840         u16 cs_bits = OCFS2_SB(inode->i_sb)->s_clustersize_bits;
841         u32 cpos, cend, clen, hole_size;
842         u64 extoff, extlen;
843         struct buffer_head *di_bh = NULL;
844         struct ocfs2_extent_rec rec;
845 
846         BUG_ON(whence != SEEK_DATA && whence != SEEK_HOLE);
847 
848         ret = ocfs2_inode_lock(inode, &di_bh, 0);
849         if (ret) {
850                 mlog_errno(ret);
851                 goto out;
852         }
853 
854         down_read(&OCFS2_I(inode)->ip_alloc_sem);
855 
856         if (*offset >= i_size_read(inode)) {
857                 ret = -ENXIO;
858                 goto out_unlock;
859         }
860 
861         if (OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL) {
862                 if (whence == SEEK_HOLE)
863                         *offset = i_size_read(inode);
864                 goto out_unlock;
865         }
866 
867         clen = 0;
868         cpos = *offset >> cs_bits;
869         cend = ocfs2_clusters_for_bytes(inode->i_sb, i_size_read(inode));
870 
871         while (cpos < cend && !is_last) {
872                 ret = ocfs2_get_clusters_nocache(inode, di_bh, cpos, &hole_size,
873                                                  &rec, &is_last);
874                 if (ret) {
875                         mlog_errno(ret);
876                         goto out_unlock;
877                 }
878 
879                 extoff = cpos;
880                 extoff <<= cs_bits;
881 
882                 if (rec.e_blkno == 0ULL) {
883                         clen = hole_size;
884                         is_data = 0;
885                 } else {
886                         clen = le16_to_cpu(rec.e_leaf_clusters) -
887                                 (cpos - le32_to_cpu(rec.e_cpos));
888                         is_data = (rec.e_flags & OCFS2_EXT_UNWRITTEN) ?  0 : 1;
889                 }
890 
891                 if ((!is_data && whence == SEEK_HOLE) ||
892                     (is_data && whence == SEEK_DATA)) {
893                         if (extoff > *offset)
894                                 *offset = extoff;
895                         goto out_unlock;
896                 }
897 
898                 if (!is_last)
899                         cpos += clen;
900         }
901 
902         if (whence == SEEK_HOLE) {
903                 extoff = cpos;
904                 extoff <<= cs_bits;
905                 extlen = clen;
906                 extlen <<=  cs_bits;
907 
908                 if ((extoff + extlen) > i_size_read(inode))
909                         extlen = i_size_read(inode) - extoff;
910                 extoff += extlen;
911                 if (extoff > *offset)
912                         *offset = extoff;
913                 goto out_unlock;
914         }
915 
916         ret = -ENXIO;
917 
918 out_unlock:
919 
920         brelse(di_bh);
921 
922         up_read(&OCFS2_I(inode)->ip_alloc_sem);
923 
924         ocfs2_inode_unlock(inode, 0);
925 out:
926         return ret;
927 }
928 
929 int ocfs2_read_virt_blocks(struct inode *inode, u64 v_block, int nr,
930                            struct buffer_head *bhs[], int flags,
931                            int (*validate)(struct super_block *sb,
932                                            struct buffer_head *bh))
933 {
934         int rc = 0;
935         u64 p_block, p_count;
936         int i, count, done = 0;
937 
938         trace_ocfs2_read_virt_blocks(
939              inode, (unsigned long long)v_block, nr, bhs, flags,
940              validate);
941 
942         if (((v_block + nr - 1) << inode->i_sb->s_blocksize_bits) >=
943             i_size_read(inode)) {
944                 BUG_ON(!(flags & OCFS2_BH_READAHEAD));
945                 goto out;
946         }
947 
948         while (done < nr) {
949                 down_read(&OCFS2_I(inode)->ip_alloc_sem);
950                 rc = ocfs2_extent_map_get_blocks(inode, v_block + done,
951                                                  &p_block, &p_count, NULL);
952                 up_read(&OCFS2_I(inode)->ip_alloc_sem);
953                 if (rc) {
954                         mlog_errno(rc);
955                         break;
956                 }
957 
958                 if (!p_block) {
959                         rc = -EIO;
960                         mlog(ML_ERROR,
961                              "Inode #%llu contains a hole at offset %llu\n",
962                              (unsigned long long)OCFS2_I(inode)->ip_blkno,
963                              (unsigned long long)(v_block + done) <<
964                              inode->i_sb->s_blocksize_bits);
965                         break;
966                 }
967 
968                 count = nr - done;
969                 if (p_count < count)
970                         count = p_count;
971 
972                 /*
973                  * If the caller passed us bhs, they should have come
974                  * from a previous readahead call to this function.  Thus,
975                  * they should have the right b_blocknr.
976                  */
977                 for (i = 0; i < count; i++) {
978                         if (!bhs[done + i])
979                                 continue;
980                         BUG_ON(bhs[done + i]->b_blocknr != (p_block + i));
981                 }
982 
983                 rc = ocfs2_read_blocks(INODE_CACHE(inode), p_block, count,
984                                        bhs + done, flags, validate);
985                 if (rc) {
986                         mlog_errno(rc);
987                         break;
988                 }
989                 done += count;
990         }
991 
992 out:
993         return rc;
994 }
995 
996 
997 

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