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Linux/fs/ocfs2/extent_map.c

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  1 // SPDX-License-Identifier: GPL-2.0-only
  2 /* -*- mode: c; c-basic-offset: 8; -*-
  3  * vim: noexpandtab sw=8 ts=8 sts=0:
  4  *
  5  * extent_map.c
  6  *
  7  * Block/Cluster mapping functions
  8  *
  9  * Copyright (C) 2004 Oracle.  All rights reserved.
 10  */
 11 
 12 #include <linux/fs.h>
 13 #include <linux/init.h>
 14 #include <linux/slab.h>
 15 #include <linux/types.h>
 16 #include <linux/fiemap.h>
 17 
 18 #include <cluster/masklog.h>
 19 
 20 #include "ocfs2.h"
 21 
 22 #include "alloc.h"
 23 #include "dlmglue.h"
 24 #include "extent_map.h"
 25 #include "inode.h"
 26 #include "super.h"
 27 #include "symlink.h"
 28 #include "aops.h"
 29 #include "ocfs2_trace.h"
 30 
 31 #include "buffer_head_io.h"
 32 
 33 /*
 34  * The extent caching implementation is intentionally trivial.
 35  *
 36  * We only cache a small number of extents stored directly on the
 37  * inode, so linear order operations are acceptable. If we ever want
 38  * to increase the size of the extent map, then these algorithms must
 39  * get smarter.
 40  */
 41 
 42 void ocfs2_extent_map_init(struct inode *inode)
 43 {
 44         struct ocfs2_inode_info *oi = OCFS2_I(inode);
 45 
 46         oi->ip_extent_map.em_num_items = 0;
 47         INIT_LIST_HEAD(&oi->ip_extent_map.em_list);
 48 }
 49 
 50 static void __ocfs2_extent_map_lookup(struct ocfs2_extent_map *em,
 51                                       unsigned int cpos,
 52                                       struct ocfs2_extent_map_item **ret_emi)
 53 {
 54         unsigned int range;
 55         struct ocfs2_extent_map_item *emi;
 56 
 57         *ret_emi = NULL;
 58 
 59         list_for_each_entry(emi, &em->em_list, ei_list) {
 60                 range = emi->ei_cpos + emi->ei_clusters;
 61 
 62                 if (cpos >= emi->ei_cpos && cpos < range) {
 63                         list_move(&emi->ei_list, &em->em_list);
 64 
 65                         *ret_emi = emi;
 66                         break;
 67                 }
 68         }
 69 }
 70 
 71 static int ocfs2_extent_map_lookup(struct inode *inode, unsigned int cpos,
 72                                    unsigned int *phys, unsigned int *len,
 73                                    unsigned int *flags)
 74 {
 75         unsigned int coff;
 76         struct ocfs2_inode_info *oi = OCFS2_I(inode);
 77         struct ocfs2_extent_map_item *emi;
 78 
 79         spin_lock(&oi->ip_lock);
 80 
 81         __ocfs2_extent_map_lookup(&oi->ip_extent_map, cpos, &emi);
 82         if (emi) {
 83                 coff = cpos - emi->ei_cpos;
 84                 *phys = emi->ei_phys + coff;
 85                 if (len)
 86                         *len = emi->ei_clusters - coff;
 87                 if (flags)
 88                         *flags = emi->ei_flags;
 89         }
 90 
 91         spin_unlock(&oi->ip_lock);
 92 
 93         if (emi == NULL)
 94                 return -ENOENT;
 95 
 96         return 0;
 97 }
 98 
 99 /*
100  * Forget about all clusters equal to or greater than cpos.
101  */
102 void ocfs2_extent_map_trunc(struct inode *inode, unsigned int cpos)
103 {
104         struct ocfs2_extent_map_item *emi, *n;
105         struct ocfs2_inode_info *oi = OCFS2_I(inode);
106         struct ocfs2_extent_map *em = &oi->ip_extent_map;
107         LIST_HEAD(tmp_list);
108         unsigned int range;
109 
110         spin_lock(&oi->ip_lock);
111         list_for_each_entry_safe(emi, n, &em->em_list, ei_list) {
112                 if (emi->ei_cpos >= cpos) {
113                         /* Full truncate of this record. */
114                         list_move(&emi->ei_list, &tmp_list);
115                         BUG_ON(em->em_num_items == 0);
116                         em->em_num_items--;
117                         continue;
118                 }
119 
120                 range = emi->ei_cpos + emi->ei_clusters;
121                 if (range > cpos) {
122                         /* Partial truncate */
123                         emi->ei_clusters = cpos - emi->ei_cpos;
124                 }
125         }
126         spin_unlock(&oi->ip_lock);
127 
128         list_for_each_entry_safe(emi, n, &tmp_list, ei_list) {
129                 list_del(&emi->ei_list);
130                 kfree(emi);
131         }
132 }
133 
134 /*
135  * Is any part of emi2 contained within emi1
136  */
137 static int ocfs2_ei_is_contained(struct ocfs2_extent_map_item *emi1,
138                                  struct ocfs2_extent_map_item *emi2)
139 {
140         unsigned int range1, range2;
141 
142         /*
143          * Check if logical start of emi2 is inside emi1
144          */
145         range1 = emi1->ei_cpos + emi1->ei_clusters;
146         if (emi2->ei_cpos >= emi1->ei_cpos && emi2->ei_cpos < range1)
147                 return 1;
148 
149         /*
150          * Check if logical end of emi2 is inside emi1
151          */
152         range2 = emi2->ei_cpos + emi2->ei_clusters;
153         if (range2 > emi1->ei_cpos && range2 <= range1)
154                 return 1;
155 
156         return 0;
157 }
158 
159 static void ocfs2_copy_emi_fields(struct ocfs2_extent_map_item *dest,
160                                   struct ocfs2_extent_map_item *src)
161 {
162         dest->ei_cpos = src->ei_cpos;
163         dest->ei_phys = src->ei_phys;
164         dest->ei_clusters = src->ei_clusters;
165         dest->ei_flags = src->ei_flags;
166 }
167 
168 /*
169  * Try to merge emi with ins. Returns 1 if merge succeeds, zero
170  * otherwise.
171  */
172 static int ocfs2_try_to_merge_extent_map(struct ocfs2_extent_map_item *emi,
173                                          struct ocfs2_extent_map_item *ins)
174 {
175         /*
176          * Handle contiguousness
177          */
178         if (ins->ei_phys == (emi->ei_phys + emi->ei_clusters) &&
179             ins->ei_cpos == (emi->ei_cpos + emi->ei_clusters) &&
180             ins->ei_flags == emi->ei_flags) {
181                 emi->ei_clusters += ins->ei_clusters;
182                 return 1;
183         } else if ((ins->ei_phys + ins->ei_clusters) == emi->ei_phys &&
184                    (ins->ei_cpos + ins->ei_clusters) == emi->ei_cpos &&
185                    ins->ei_flags == emi->ei_flags) {
186                 emi->ei_phys = ins->ei_phys;
187                 emi->ei_cpos = ins->ei_cpos;
188                 emi->ei_clusters += ins->ei_clusters;
189                 return 1;
190         }
191 
192         /*
193          * Overlapping extents - this shouldn't happen unless we've
194          * split an extent to change it's flags. That is exceedingly
195          * rare, so there's no sense in trying to optimize it yet.
196          */
197         if (ocfs2_ei_is_contained(emi, ins) ||
198             ocfs2_ei_is_contained(ins, emi)) {
199                 ocfs2_copy_emi_fields(emi, ins);
200                 return 1;
201         }
202 
203         /* No merge was possible. */
204         return 0;
205 }
206 
207 /*
208  * In order to reduce complexity on the caller, this insert function
209  * is intentionally liberal in what it will accept.
210  *
211  * The only rule is that the truncate call *must* be used whenever
212  * records have been deleted. This avoids inserting overlapping
213  * records with different physical mappings.
214  */
215 void ocfs2_extent_map_insert_rec(struct inode *inode,
216                                  struct ocfs2_extent_rec *rec)
217 {
218         struct ocfs2_inode_info *oi = OCFS2_I(inode);
219         struct ocfs2_extent_map *em = &oi->ip_extent_map;
220         struct ocfs2_extent_map_item *emi, *new_emi = NULL;
221         struct ocfs2_extent_map_item ins;
222 
223         ins.ei_cpos = le32_to_cpu(rec->e_cpos);
224         ins.ei_phys = ocfs2_blocks_to_clusters(inode->i_sb,
225                                                le64_to_cpu(rec->e_blkno));
226         ins.ei_clusters = le16_to_cpu(rec->e_leaf_clusters);
227         ins.ei_flags = rec->e_flags;
228 
229 search:
230         spin_lock(&oi->ip_lock);
231 
232         list_for_each_entry(emi, &em->em_list, ei_list) {
233                 if (ocfs2_try_to_merge_extent_map(emi, &ins)) {
234                         list_move(&emi->ei_list, &em->em_list);
235                         spin_unlock(&oi->ip_lock);
236                         goto out;
237                 }
238         }
239 
240         /*
241          * No item could be merged.
242          *
243          * Either allocate and add a new item, or overwrite the last recently
244          * inserted.
245          */
246 
247         if (em->em_num_items < OCFS2_MAX_EXTENT_MAP_ITEMS) {
248                 if (new_emi == NULL) {
249                         spin_unlock(&oi->ip_lock);
250 
251                         new_emi = kmalloc(sizeof(*new_emi), GFP_NOFS);
252                         if (new_emi == NULL)
253                                 goto out;
254 
255                         goto search;
256                 }
257 
258                 ocfs2_copy_emi_fields(new_emi, &ins);
259                 list_add(&new_emi->ei_list, &em->em_list);
260                 em->em_num_items++;
261                 new_emi = NULL;
262         } else {
263                 BUG_ON(list_empty(&em->em_list) || em->em_num_items == 0);
264                 emi = list_entry(em->em_list.prev,
265                                  struct ocfs2_extent_map_item, ei_list);
266                 list_move(&emi->ei_list, &em->em_list);
267                 ocfs2_copy_emi_fields(emi, &ins);
268         }
269 
270         spin_unlock(&oi->ip_lock);
271 
272 out:
273         kfree(new_emi);
274 }
275 
276 static int ocfs2_last_eb_is_empty(struct inode *inode,
277                                   struct ocfs2_dinode *di)
278 {
279         int ret, next_free;
280         u64 last_eb_blk = le64_to_cpu(di->i_last_eb_blk);
281         struct buffer_head *eb_bh = NULL;
282         struct ocfs2_extent_block *eb;
283         struct ocfs2_extent_list *el;
284 
285         ret = ocfs2_read_extent_block(INODE_CACHE(inode), last_eb_blk, &eb_bh);
286         if (ret) {
287                 mlog_errno(ret);
288                 goto out;
289         }
290 
291         eb = (struct ocfs2_extent_block *) eb_bh->b_data;
292         el = &eb->h_list;
293 
294         if (el->l_tree_depth) {
295                 ocfs2_error(inode->i_sb,
296                             "Inode %lu has non zero tree depth in leaf block %llu\n",
297                             inode->i_ino,
298                             (unsigned long long)eb_bh->b_blocknr);
299                 ret = -EROFS;
300                 goto out;
301         }
302 
303         next_free = le16_to_cpu(el->l_next_free_rec);
304 
305         if (next_free == 0 ||
306             (next_free == 1 && ocfs2_is_empty_extent(&el->l_recs[0])))
307                 ret = 1;
308 
309 out:
310         brelse(eb_bh);
311         return ret;
312 }
313 
314 /*
315  * Return the 1st index within el which contains an extent start
316  * larger than v_cluster.
317  */
318 static int ocfs2_search_for_hole_index(struct ocfs2_extent_list *el,
319                                        u32 v_cluster)
320 {
321         int i;
322         struct ocfs2_extent_rec *rec;
323 
324         for(i = 0; i < le16_to_cpu(el->l_next_free_rec); i++) {
325                 rec = &el->l_recs[i];
326 
327                 if (v_cluster < le32_to_cpu(rec->e_cpos))
328                         break;
329         }
330 
331         return i;
332 }
333 
334 /*
335  * Figure out the size of a hole which starts at v_cluster within the given
336  * extent list.
337  *
338  * If there is no more allocation past v_cluster, we return the maximum
339  * cluster size minus v_cluster.
340  *
341  * If we have in-inode extents, then el points to the dinode list and
342  * eb_bh is NULL. Otherwise, eb_bh should point to the extent block
343  * containing el.
344  */
345 int ocfs2_figure_hole_clusters(struct ocfs2_caching_info *ci,
346                                struct ocfs2_extent_list *el,
347                                struct buffer_head *eb_bh,
348                                u32 v_cluster,
349                                u32 *num_clusters)
350 {
351         int ret, i;
352         struct buffer_head *next_eb_bh = NULL;
353         struct ocfs2_extent_block *eb, *next_eb;
354 
355         i = ocfs2_search_for_hole_index(el, v_cluster);
356 
357         if (i == le16_to_cpu(el->l_next_free_rec) && eb_bh) {
358                 eb = (struct ocfs2_extent_block *)eb_bh->b_data;
359 
360                 /*
361                  * Check the next leaf for any extents.
362                  */
363 
364                 if (le64_to_cpu(eb->h_next_leaf_blk) == 0ULL)
365                         goto no_more_extents;
366 
367                 ret = ocfs2_read_extent_block(ci,
368                                               le64_to_cpu(eb->h_next_leaf_blk),
369                                               &next_eb_bh);
370                 if (ret) {
371                         mlog_errno(ret);
372                         goto out;
373                 }
374 
375                 next_eb = (struct ocfs2_extent_block *)next_eb_bh->b_data;
376                 el = &next_eb->h_list;
377                 i = ocfs2_search_for_hole_index(el, v_cluster);
378         }
379 
380 no_more_extents:
381         if (i == le16_to_cpu(el->l_next_free_rec)) {
382                 /*
383                  * We're at the end of our existing allocation. Just
384                  * return the maximum number of clusters we could
385                  * possibly allocate.
386                  */
387                 *num_clusters = UINT_MAX - v_cluster;
388         } else {
389                 *num_clusters = le32_to_cpu(el->l_recs[i].e_cpos) - v_cluster;
390         }
391 
392         ret = 0;
393 out:
394         brelse(next_eb_bh);
395         return ret;
396 }
397 
398 static int ocfs2_get_clusters_nocache(struct inode *inode,
399                                       struct buffer_head *di_bh,
400                                       u32 v_cluster, unsigned int *hole_len,
401                                       struct ocfs2_extent_rec *ret_rec,
402                                       unsigned int *is_last)
403 {
404         int i, ret, tree_height, len;
405         struct ocfs2_dinode *di;
406         struct ocfs2_extent_block *uninitialized_var(eb);
407         struct ocfs2_extent_list *el;
408         struct ocfs2_extent_rec *rec;
409         struct buffer_head *eb_bh = NULL;
410 
411         memset(ret_rec, 0, sizeof(*ret_rec));
412         if (is_last)
413                 *is_last = 0;
414 
415         di = (struct ocfs2_dinode *) di_bh->b_data;
416         el = &di->id2.i_list;
417         tree_height = le16_to_cpu(el->l_tree_depth);
418 
419         if (tree_height > 0) {
420                 ret = ocfs2_find_leaf(INODE_CACHE(inode), el, v_cluster,
421                                       &eb_bh);
422                 if (ret) {
423                         mlog_errno(ret);
424                         goto out;
425                 }
426 
427                 eb = (struct ocfs2_extent_block *) eb_bh->b_data;
428                 el = &eb->h_list;
429 
430                 if (el->l_tree_depth) {
431                         ocfs2_error(inode->i_sb,
432                                     "Inode %lu has non zero tree depth in leaf block %llu\n",
433                                     inode->i_ino,
434                                     (unsigned long long)eb_bh->b_blocknr);
435                         ret = -EROFS;
436                         goto out;
437                 }
438         }
439 
440         i = ocfs2_search_extent_list(el, v_cluster);
441         if (i == -1) {
442                 /*
443                  * Holes can be larger than the maximum size of an
444                  * extent, so we return their lengths in a separate
445                  * field.
446                  */
447                 if (hole_len) {
448                         ret = ocfs2_figure_hole_clusters(INODE_CACHE(inode),
449                                                          el, eb_bh,
450                                                          v_cluster, &len);
451                         if (ret) {
452                                 mlog_errno(ret);
453                                 goto out;
454                         }
455 
456                         *hole_len = len;
457                 }
458                 goto out_hole;
459         }
460 
461         rec = &el->l_recs[i];
462 
463         BUG_ON(v_cluster < le32_to_cpu(rec->e_cpos));
464 
465         if (!rec->e_blkno) {
466                 ocfs2_error(inode->i_sb,
467                             "Inode %lu has bad extent record (%u, %u, 0)\n",
468                             inode->i_ino,
469                             le32_to_cpu(rec->e_cpos),
470                             ocfs2_rec_clusters(el, rec));
471                 ret = -EROFS;
472                 goto out;
473         }
474 
475         *ret_rec = *rec;
476 
477         /*
478          * Checking for last extent is potentially expensive - we
479          * might have to look at the next leaf over to see if it's
480          * empty.
481          *
482          * The first two checks are to see whether the caller even
483          * cares for this information, and if the extent is at least
484          * the last in it's list.
485          *
486          * If those hold true, then the extent is last if any of the
487          * additional conditions hold true:
488          *  - Extent list is in-inode
489          *  - Extent list is right-most
490          *  - Extent list is 2nd to rightmost, with empty right-most
491          */
492         if (is_last) {
493                 if (i == (le16_to_cpu(el->l_next_free_rec) - 1)) {
494                         if (tree_height == 0)
495                                 *is_last = 1;
496                         else if (eb->h_blkno == di->i_last_eb_blk)
497                                 *is_last = 1;
498                         else if (eb->h_next_leaf_blk == di->i_last_eb_blk) {
499                                 ret = ocfs2_last_eb_is_empty(inode, di);
500                                 if (ret < 0) {
501                                         mlog_errno(ret);
502                                         goto out;
503                                 }
504                                 if (ret == 1)
505                                         *is_last = 1;
506                         }
507                 }
508         }
509 
510 out_hole:
511         ret = 0;
512 out:
513         brelse(eb_bh);
514         return ret;
515 }
516 
517 static void ocfs2_relative_extent_offsets(struct super_block *sb,
518                                           u32 v_cluster,
519                                           struct ocfs2_extent_rec *rec,
520                                           u32 *p_cluster, u32 *num_clusters)
521 
522 {
523         u32 coff = v_cluster - le32_to_cpu(rec->e_cpos);
524 
525         *p_cluster = ocfs2_blocks_to_clusters(sb, le64_to_cpu(rec->e_blkno));
526         *p_cluster = *p_cluster + coff;
527 
528         if (num_clusters)
529                 *num_clusters = le16_to_cpu(rec->e_leaf_clusters) - coff;
530 }
531 
532 int ocfs2_xattr_get_clusters(struct inode *inode, u32 v_cluster,
533                              u32 *p_cluster, u32 *num_clusters,
534                              struct ocfs2_extent_list *el,
535                              unsigned int *extent_flags)
536 {
537         int ret = 0, i;
538         struct buffer_head *eb_bh = NULL;
539         struct ocfs2_extent_block *eb;
540         struct ocfs2_extent_rec *rec;
541         u32 coff;
542 
543         if (el->l_tree_depth) {
544                 ret = ocfs2_find_leaf(INODE_CACHE(inode), el, v_cluster,
545                                       &eb_bh);
546                 if (ret) {
547                         mlog_errno(ret);
548                         goto out;
549                 }
550 
551                 eb = (struct ocfs2_extent_block *) eb_bh->b_data;
552                 el = &eb->h_list;
553 
554                 if (el->l_tree_depth) {
555                         ocfs2_error(inode->i_sb,
556                                     "Inode %lu has non zero tree depth in xattr leaf block %llu\n",
557                                     inode->i_ino,
558                                     (unsigned long long)eb_bh->b_blocknr);
559                         ret = -EROFS;
560                         goto out;
561                 }
562         }
563 
564         i = ocfs2_search_extent_list(el, v_cluster);
565         if (i == -1) {
566                 ret = -EROFS;
567                 mlog_errno(ret);
568                 goto out;
569         } else {
570                 rec = &el->l_recs[i];
571                 BUG_ON(v_cluster < le32_to_cpu(rec->e_cpos));
572 
573                 if (!rec->e_blkno) {
574                         ocfs2_error(inode->i_sb,
575                                     "Inode %lu has bad extent record (%u, %u, 0) in xattr\n",
576                                     inode->i_ino,
577                                     le32_to_cpu(rec->e_cpos),
578                                     ocfs2_rec_clusters(el, rec));
579                         ret = -EROFS;
580                         goto out;
581                 }
582                 coff = v_cluster - le32_to_cpu(rec->e_cpos);
583                 *p_cluster = ocfs2_blocks_to_clusters(inode->i_sb,
584                                                     le64_to_cpu(rec->e_blkno));
585                 *p_cluster = *p_cluster + coff;
586                 if (num_clusters)
587                         *num_clusters = ocfs2_rec_clusters(el, rec) - coff;
588 
589                 if (extent_flags)
590                         *extent_flags = rec->e_flags;
591         }
592 out:
593         brelse(eb_bh);
594         return ret;
595 }
596 
597 int ocfs2_get_clusters(struct inode *inode, u32 v_cluster,
598                        u32 *p_cluster, u32 *num_clusters,
599                        unsigned int *extent_flags)
600 {
601         int ret;
602         unsigned int uninitialized_var(hole_len), flags = 0;
603         struct buffer_head *di_bh = NULL;
604         struct ocfs2_extent_rec rec;
605 
606         if (OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL) {
607                 ret = -ERANGE;
608                 mlog_errno(ret);
609                 goto out;
610         }
611 
612         ret = ocfs2_extent_map_lookup(inode, v_cluster, p_cluster,
613                                       num_clusters, extent_flags);
614         if (ret == 0)
615                 goto out;
616 
617         ret = ocfs2_read_inode_block(inode, &di_bh);
618         if (ret) {
619                 mlog_errno(ret);
620                 goto out;
621         }
622 
623         ret = ocfs2_get_clusters_nocache(inode, di_bh, v_cluster, &hole_len,
624                                          &rec, NULL);
625         if (ret) {
626                 mlog_errno(ret);
627                 goto out;
628         }
629 
630         if (rec.e_blkno == 0ULL) {
631                 /*
632                  * A hole was found. Return some canned values that
633                  * callers can key on. If asked for, num_clusters will
634                  * be populated with the size of the hole.
635                  */
636                 *p_cluster = 0;
637                 if (num_clusters) {
638                         *num_clusters = hole_len;
639                 }
640         } else {
641                 ocfs2_relative_extent_offsets(inode->i_sb, v_cluster, &rec,
642                                               p_cluster, num_clusters);
643                 flags = rec.e_flags;
644 
645                 ocfs2_extent_map_insert_rec(inode, &rec);
646         }
647 
648         if (extent_flags)
649                 *extent_flags = flags;
650 
651 out:
652         brelse(di_bh);
653         return ret;
654 }
655 
656 /*
657  * This expects alloc_sem to be held. The allocation cannot change at
658  * all while the map is in the process of being updated.
659  */
660 int ocfs2_extent_map_get_blocks(struct inode *inode, u64 v_blkno, u64 *p_blkno,
661                                 u64 *ret_count, unsigned int *extent_flags)
662 {
663         int ret;
664         int bpc = ocfs2_clusters_to_blocks(inode->i_sb, 1);
665         u32 cpos, num_clusters, p_cluster;
666         u64 boff = 0;
667 
668         cpos = ocfs2_blocks_to_clusters(inode->i_sb, v_blkno);
669 
670         ret = ocfs2_get_clusters(inode, cpos, &p_cluster, &num_clusters,
671                                  extent_flags);
672         if (ret) {
673                 mlog_errno(ret);
674                 goto out;
675         }
676 
677         /*
678          * p_cluster == 0 indicates a hole.
679          */
680         if (p_cluster) {
681                 boff = ocfs2_clusters_to_blocks(inode->i_sb, p_cluster);
682                 boff += (v_blkno & (u64)(bpc - 1));
683         }
684 
685         *p_blkno = boff;
686 
687         if (ret_count) {
688                 *ret_count = ocfs2_clusters_to_blocks(inode->i_sb, num_clusters);
689                 *ret_count -= v_blkno & (u64)(bpc - 1);
690         }
691 
692 out:
693         return ret;
694 }
695 
696 /*
697  * The ocfs2_fiemap_inline() may be a little bit misleading, since
698  * it not only handles the fiemap for inlined files, but also deals
699  * with the fast symlink, cause they have no difference for extent
700  * mapping per se.
701  */
702 static int ocfs2_fiemap_inline(struct inode *inode, struct buffer_head *di_bh,
703                                struct fiemap_extent_info *fieinfo,
704                                u64 map_start)
705 {
706         int ret;
707         unsigned int id_count;
708         struct ocfs2_dinode *di;
709         u64 phys;
710         u32 flags = FIEMAP_EXTENT_DATA_INLINE|FIEMAP_EXTENT_LAST;
711         struct ocfs2_inode_info *oi = OCFS2_I(inode);
712 
713         di = (struct ocfs2_dinode *)di_bh->b_data;
714         if (ocfs2_inode_is_fast_symlink(inode))
715                 id_count = ocfs2_fast_symlink_chars(inode->i_sb);
716         else
717                 id_count = le16_to_cpu(di->id2.i_data.id_count);
718 
719         if (map_start < id_count) {
720                 phys = oi->ip_blkno << inode->i_sb->s_blocksize_bits;
721                 if (ocfs2_inode_is_fast_symlink(inode))
722                         phys += offsetof(struct ocfs2_dinode, id2.i_symlink);
723                 else
724                         phys += offsetof(struct ocfs2_dinode,
725                                          id2.i_data.id_data);
726 
727                 ret = fiemap_fill_next_extent(fieinfo, 0, phys, id_count,
728                                               flags);
729                 if (ret < 0)
730                         return ret;
731         }
732 
733         return 0;
734 }
735 
736 #define OCFS2_FIEMAP_FLAGS      (FIEMAP_FLAG_SYNC)
737 
738 int ocfs2_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
739                  u64 map_start, u64 map_len)
740 {
741         int ret, is_last;
742         u32 mapping_end, cpos;
743         unsigned int hole_size;
744         struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
745         u64 len_bytes, phys_bytes, virt_bytes;
746         struct buffer_head *di_bh = NULL;
747         struct ocfs2_extent_rec rec;
748 
749         ret = fiemap_check_flags(fieinfo, OCFS2_FIEMAP_FLAGS);
750         if (ret)
751                 return ret;
752 
753         ret = ocfs2_inode_lock(inode, &di_bh, 0);
754         if (ret) {
755                 mlog_errno(ret);
756                 goto out;
757         }
758 
759         down_read(&OCFS2_I(inode)->ip_alloc_sem);
760 
761         /*
762          * Handle inline-data and fast symlink separately.
763          */
764         if ((OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL) ||
765             ocfs2_inode_is_fast_symlink(inode)) {
766                 ret = ocfs2_fiemap_inline(inode, di_bh, fieinfo, map_start);
767                 goto out_unlock;
768         }
769 
770         cpos = map_start >> osb->s_clustersize_bits;
771         mapping_end = ocfs2_clusters_for_bytes(inode->i_sb,
772                                                map_start + map_len);
773         is_last = 0;
774         while (cpos < mapping_end && !is_last) {
775                 u32 fe_flags;
776 
777                 ret = ocfs2_get_clusters_nocache(inode, di_bh, cpos,
778                                                  &hole_size, &rec, &is_last);
779                 if (ret) {
780                         mlog_errno(ret);
781                         goto out_unlock;
782                 }
783 
784                 if (rec.e_blkno == 0ULL) {
785                         cpos += hole_size;
786                         continue;
787                 }
788 
789                 fe_flags = 0;
790                 if (rec.e_flags & OCFS2_EXT_UNWRITTEN)
791                         fe_flags |= FIEMAP_EXTENT_UNWRITTEN;
792                 if (rec.e_flags & OCFS2_EXT_REFCOUNTED)
793                         fe_flags |= FIEMAP_EXTENT_SHARED;
794                 if (is_last)
795                         fe_flags |= FIEMAP_EXTENT_LAST;
796                 len_bytes = (u64)le16_to_cpu(rec.e_leaf_clusters) << osb->s_clustersize_bits;
797                 phys_bytes = le64_to_cpu(rec.e_blkno) << osb->sb->s_blocksize_bits;
798                 virt_bytes = (u64)le32_to_cpu(rec.e_cpos) << osb->s_clustersize_bits;
799 
800                 ret = fiemap_fill_next_extent(fieinfo, virt_bytes, phys_bytes,
801                                               len_bytes, fe_flags);
802                 if (ret)
803                         break;
804 
805                 cpos = le32_to_cpu(rec.e_cpos)+ le16_to_cpu(rec.e_leaf_clusters);
806         }
807 
808         if (ret > 0)
809                 ret = 0;
810 
811 out_unlock:
812         brelse(di_bh);
813 
814         up_read(&OCFS2_I(inode)->ip_alloc_sem);
815 
816         ocfs2_inode_unlock(inode, 0);
817 out:
818 
819         return ret;
820 }
821 
822 /* Is IO overwriting allocated blocks? */
823 int ocfs2_overwrite_io(struct inode *inode, struct buffer_head *di_bh,
824                        u64 map_start, u64 map_len)
825 {
826         int ret = 0, is_last;
827         u32 mapping_end, cpos;
828         struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
829         struct ocfs2_extent_rec rec;
830 
831         if (OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL) {
832                 if (ocfs2_size_fits_inline_data(di_bh, map_start + map_len))
833                         return ret;
834                 else
835                         return -EAGAIN;
836         }
837 
838         cpos = map_start >> osb->s_clustersize_bits;
839         mapping_end = ocfs2_clusters_for_bytes(inode->i_sb,
840                                                map_start + map_len);
841         is_last = 0;
842         while (cpos < mapping_end && !is_last) {
843                 ret = ocfs2_get_clusters_nocache(inode, di_bh, cpos,
844                                                  NULL, &rec, &is_last);
845                 if (ret) {
846                         mlog_errno(ret);
847                         goto out;
848                 }
849 
850                 if (rec.e_blkno == 0ULL)
851                         break;
852 
853                 if (rec.e_flags & OCFS2_EXT_REFCOUNTED)
854                         break;
855 
856                 cpos = le32_to_cpu(rec.e_cpos) +
857                         le16_to_cpu(rec.e_leaf_clusters);
858         }
859 
860         if (cpos < mapping_end)
861                 ret = -EAGAIN;
862 out:
863         return ret;
864 }
865 
866 int ocfs2_seek_data_hole_offset(struct file *file, loff_t *offset, int whence)
867 {
868         struct inode *inode = file->f_mapping->host;
869         int ret;
870         unsigned int is_last = 0, is_data = 0;
871         u16 cs_bits = OCFS2_SB(inode->i_sb)->s_clustersize_bits;
872         u32 cpos, cend, clen, hole_size;
873         u64 extoff, extlen;
874         struct buffer_head *di_bh = NULL;
875         struct ocfs2_extent_rec rec;
876 
877         BUG_ON(whence != SEEK_DATA && whence != SEEK_HOLE);
878 
879         ret = ocfs2_inode_lock(inode, &di_bh, 0);
880         if (ret) {
881                 mlog_errno(ret);
882                 goto out;
883         }
884 
885         down_read(&OCFS2_I(inode)->ip_alloc_sem);
886 
887         if (*offset >= i_size_read(inode)) {
888                 ret = -ENXIO;
889                 goto out_unlock;
890         }
891 
892         if (OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL) {
893                 if (whence == SEEK_HOLE)
894                         *offset = i_size_read(inode);
895                 goto out_unlock;
896         }
897 
898         clen = 0;
899         cpos = *offset >> cs_bits;
900         cend = ocfs2_clusters_for_bytes(inode->i_sb, i_size_read(inode));
901 
902         while (cpos < cend && !is_last) {
903                 ret = ocfs2_get_clusters_nocache(inode, di_bh, cpos, &hole_size,
904                                                  &rec, &is_last);
905                 if (ret) {
906                         mlog_errno(ret);
907                         goto out_unlock;
908                 }
909 
910                 extoff = cpos;
911                 extoff <<= cs_bits;
912 
913                 if (rec.e_blkno == 0ULL) {
914                         clen = hole_size;
915                         is_data = 0;
916                 } else {
917                         clen = le16_to_cpu(rec.e_leaf_clusters) -
918                                 (cpos - le32_to_cpu(rec.e_cpos));
919                         is_data = (rec.e_flags & OCFS2_EXT_UNWRITTEN) ?  0 : 1;
920                 }
921 
922                 if ((!is_data && whence == SEEK_HOLE) ||
923                     (is_data && whence == SEEK_DATA)) {
924                         if (extoff > *offset)
925                                 *offset = extoff;
926                         goto out_unlock;
927                 }
928 
929                 if (!is_last)
930                         cpos += clen;
931         }
932 
933         if (whence == SEEK_HOLE) {
934                 extoff = cpos;
935                 extoff <<= cs_bits;
936                 extlen = clen;
937                 extlen <<=  cs_bits;
938 
939                 if ((extoff + extlen) > i_size_read(inode))
940                         extlen = i_size_read(inode) - extoff;
941                 extoff += extlen;
942                 if (extoff > *offset)
943                         *offset = extoff;
944                 goto out_unlock;
945         }
946 
947         ret = -ENXIO;
948 
949 out_unlock:
950 
951         brelse(di_bh);
952 
953         up_read(&OCFS2_I(inode)->ip_alloc_sem);
954 
955         ocfs2_inode_unlock(inode, 0);
956 out:
957         return ret;
958 }
959 
960 int ocfs2_read_virt_blocks(struct inode *inode, u64 v_block, int nr,
961                            struct buffer_head *bhs[], int flags,
962                            int (*validate)(struct super_block *sb,
963                                            struct buffer_head *bh))
964 {
965         int rc = 0;
966         u64 p_block, p_count;
967         int i, count, done = 0;
968 
969         trace_ocfs2_read_virt_blocks(
970              inode, (unsigned long long)v_block, nr, bhs, flags,
971              validate);
972 
973         if (((v_block + nr - 1) << inode->i_sb->s_blocksize_bits) >=
974             i_size_read(inode)) {
975                 BUG_ON(!(flags & OCFS2_BH_READAHEAD));
976                 goto out;
977         }
978 
979         while (done < nr) {
980                 down_read(&OCFS2_I(inode)->ip_alloc_sem);
981                 rc = ocfs2_extent_map_get_blocks(inode, v_block + done,
982                                                  &p_block, &p_count, NULL);
983                 up_read(&OCFS2_I(inode)->ip_alloc_sem);
984                 if (rc) {
985                         mlog_errno(rc);
986                         break;
987                 }
988 
989                 if (!p_block) {
990                         rc = -EIO;
991                         mlog(ML_ERROR,
992                              "Inode #%llu contains a hole at offset %llu\n",
993                              (unsigned long long)OCFS2_I(inode)->ip_blkno,
994                              (unsigned long long)(v_block + done) <<
995                              inode->i_sb->s_blocksize_bits);
996                         break;
997                 }
998 
999                 count = nr - done;
1000                 if (p_count < count)
1001                         count = p_count;
1002 
1003                 /*
1004                  * If the caller passed us bhs, they should have come
1005                  * from a previous readahead call to this function.  Thus,
1006                  * they should have the right b_blocknr.
1007                  */
1008                 for (i = 0; i < count; i++) {
1009                         if (!bhs[done + i])
1010                                 continue;
1011                         BUG_ON(bhs[done + i]->b_blocknr != (p_block + i));
1012                 }
1013 
1014                 rc = ocfs2_read_blocks(INODE_CACHE(inode), p_block, count,
1015                                        bhs + done, flags, validate);
1016                 if (rc) {
1017                         mlog_errno(rc);
1018                         break;
1019                 }
1020                 done += count;
1021         }
1022 
1023 out:
1024         return rc;
1025 }
1026 
1027 
1028 

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