Root/fs/ocfs2/extent_map.c

1/* -*- mode: c; c-basic-offset: 8; -*-
2 * vim: noexpandtab sw=8 ts=8 sts=0:
3 *
4 * extent_map.c
5 *
6 * Block/Cluster mapping functions
7 *
8 * Copyright (C) 2004 Oracle. All rights reserved.
9 *
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public
12 * License, version 2, as published by the Free Software Foundation.
13 *
14 * This program is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17 * General Public License for more details.
18 *
19 * You should have received a copy of the GNU General Public
20 * License along with this program; if not, write to the
21 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
22 * Boston, MA 021110-1307, USA.
23 */
24
25#include <linux/fs.h>
26#include <linux/init.h>
27#include <linux/slab.h>
28#include <linux/types.h>
29#include <linux/fiemap.h>
30
31#define MLOG_MASK_PREFIX ML_EXTENT_MAP
32#include <cluster/masklog.h>
33
34#include "ocfs2.h"
35
36#include "alloc.h"
37#include "dlmglue.h"
38#include "extent_map.h"
39#include "inode.h"
40#include "super.h"
41#include "symlink.h"
42
43#include "buffer_head_io.h"
44
45/*
46 * The extent caching implementation is intentionally trivial.
47 *
48 * We only cache a small number of extents stored directly on the
49 * inode, so linear order operations are acceptable. If we ever want
50 * to increase the size of the extent map, then these algorithms must
51 * get smarter.
52 */
53
54void 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
62static 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
83static 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 */
114void 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 */
149static 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
171static 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 */
184static 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 */
227void 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
241search:
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
284out:
285    if (new_emi)
286        kfree(new_emi);
287}
288
289static int ocfs2_last_eb_is_empty(struct inode *inode,
290                  struct ocfs2_dinode *di)
291{
292    int ret, next_free;
293    u64 last_eb_blk = le64_to_cpu(di->i_last_eb_blk);
294    struct buffer_head *eb_bh = NULL;
295    struct ocfs2_extent_block *eb;
296    struct ocfs2_extent_list *el;
297
298    ret = ocfs2_read_extent_block(INODE_CACHE(inode), last_eb_blk, &eb_bh);
299    if (ret) {
300        mlog_errno(ret);
301        goto out;
302    }
303
304    eb = (struct ocfs2_extent_block *) eb_bh->b_data;
305    el = &eb->h_list;
306
307    if (el->l_tree_depth) {
308        ocfs2_error(inode->i_sb,
309                "Inode %lu has non zero tree depth in "
310                "leaf block %llu\n", inode->i_ino,
311                (unsigned long long)eb_bh->b_blocknr);
312        ret = -EROFS;
313        goto out;
314    }
315
316    next_free = le16_to_cpu(el->l_next_free_rec);
317
318    if (next_free == 0 ||
319        (next_free == 1 && ocfs2_is_empty_extent(&el->l_recs[0])))
320        ret = 1;
321
322out:
323    brelse(eb_bh);
324    return ret;
325}
326
327/*
328 * Return the 1st index within el which contains an extent start
329 * larger than v_cluster.
330 */
331static int ocfs2_search_for_hole_index(struct ocfs2_extent_list *el,
332                       u32 v_cluster)
333{
334    int i;
335    struct ocfs2_extent_rec *rec;
336
337    for(i = 0; i < le16_to_cpu(el->l_next_free_rec); i++) {
338        rec = &el->l_recs[i];
339
340        if (v_cluster < le32_to_cpu(rec->e_cpos))
341            break;
342    }
343
344    return i;
345}
346
347/*
348 * Figure out the size of a hole which starts at v_cluster within the given
349 * extent list.
350 *
351 * If there is no more allocation past v_cluster, we return the maximum
352 * cluster size minus v_cluster.
353 *
354 * If we have in-inode extents, then el points to the dinode list and
355 * eb_bh is NULL. Otherwise, eb_bh should point to the extent block
356 * containing el.
357 */
358int ocfs2_figure_hole_clusters(struct ocfs2_caching_info *ci,
359                   struct ocfs2_extent_list *el,
360                   struct buffer_head *eb_bh,
361                   u32 v_cluster,
362                   u32 *num_clusters)
363{
364    int ret, i;
365    struct buffer_head *next_eb_bh = NULL;
366    struct ocfs2_extent_block *eb, *next_eb;
367
368    i = ocfs2_search_for_hole_index(el, v_cluster);
369
370    if (i == le16_to_cpu(el->l_next_free_rec) && eb_bh) {
371        eb = (struct ocfs2_extent_block *)eb_bh->b_data;
372
373        /*
374         * Check the next leaf for any extents.
375         */
376
377        if (le64_to_cpu(eb->h_next_leaf_blk) == 0ULL)
378            goto no_more_extents;
379
380        ret = ocfs2_read_extent_block(ci,
381                          le64_to_cpu(eb->h_next_leaf_blk),
382                          &next_eb_bh);
383        if (ret) {
384            mlog_errno(ret);
385            goto out;
386        }
387
388        next_eb = (struct ocfs2_extent_block *)next_eb_bh->b_data;
389        el = &next_eb->h_list;
390        i = ocfs2_search_for_hole_index(el, v_cluster);
391    }
392
393no_more_extents:
394    if (i == le16_to_cpu(el->l_next_free_rec)) {
395        /*
396         * We're at the end of our existing allocation. Just
397         * return the maximum number of clusters we could
398         * possibly allocate.
399         */
400        *num_clusters = UINT_MAX - v_cluster;
401    } else {
402        *num_clusters = le32_to_cpu(el->l_recs[i].e_cpos) - v_cluster;
403    }
404
405    ret = 0;
406out:
407    brelse(next_eb_bh);
408    return ret;
409}
410
411static int ocfs2_get_clusters_nocache(struct inode *inode,
412                      struct buffer_head *di_bh,
413                      u32 v_cluster, unsigned int *hole_len,
414                      struct ocfs2_extent_rec *ret_rec,
415                      unsigned int *is_last)
416{
417    int i, ret, tree_height, len;
418    struct ocfs2_dinode *di;
419    struct ocfs2_extent_block *uninitialized_var(eb);
420    struct ocfs2_extent_list *el;
421    struct ocfs2_extent_rec *rec;
422    struct buffer_head *eb_bh = NULL;
423
424    memset(ret_rec, 0, sizeof(*ret_rec));
425    if (is_last)
426        *is_last = 0;
427
428    di = (struct ocfs2_dinode *) di_bh->b_data;
429    el = &di->id2.i_list;
430    tree_height = le16_to_cpu(el->l_tree_depth);
431
432    if (tree_height > 0) {
433        ret = ocfs2_find_leaf(INODE_CACHE(inode), el, v_cluster,
434                      &eb_bh);
435        if (ret) {
436            mlog_errno(ret);
437            goto out;
438        }
439
440        eb = (struct ocfs2_extent_block *) eb_bh->b_data;
441        el = &eb->h_list;
442
443        if (el->l_tree_depth) {
444            ocfs2_error(inode->i_sb,
445                    "Inode %lu has non zero tree depth in "
446                    "leaf block %llu\n", inode->i_ino,
447                    (unsigned long long)eb_bh->b_blocknr);
448            ret = -EROFS;
449            goto out;
450        }
451    }
452
453    i = ocfs2_search_extent_list(el, v_cluster);
454    if (i == -1) {
455        /*
456         * Holes can be larger than the maximum size of an
457         * extent, so we return their lengths in a separate
458         * field.
459         */
460        if (hole_len) {
461            ret = ocfs2_figure_hole_clusters(INODE_CACHE(inode),
462                             el, eb_bh,
463                             v_cluster, &len);
464            if (ret) {
465                mlog_errno(ret);
466                goto out;
467            }
468
469            *hole_len = len;
470        }
471        goto out_hole;
472    }
473
474    rec = &el->l_recs[i];
475
476    BUG_ON(v_cluster < le32_to_cpu(rec->e_cpos));
477
478    if (!rec->e_blkno) {
479        ocfs2_error(inode->i_sb, "Inode %lu has bad extent "
480                "record (%u, %u, 0)", inode->i_ino,
481                le32_to_cpu(rec->e_cpos),
482                ocfs2_rec_clusters(el, rec));
483        ret = -EROFS;
484        goto out;
485    }
486
487    *ret_rec = *rec;
488
489    /*
490     * Checking for last extent is potentially expensive - we
491     * might have to look at the next leaf over to see if it's
492     * empty.
493     *
494     * The first two checks are to see whether the caller even
495     * cares for this information, and if the extent is at least
496     * the last in it's list.
497     *
498     * If those hold true, then the extent is last if any of the
499     * additional conditions hold true:
500     * - Extent list is in-inode
501     * - Extent list is right-most
502     * - Extent list is 2nd to rightmost, with empty right-most
503     */
504    if (is_last) {
505        if (i == (le16_to_cpu(el->l_next_free_rec) - 1)) {
506            if (tree_height == 0)
507                *is_last = 1;
508            else if (eb->h_blkno == di->i_last_eb_blk)
509                *is_last = 1;
510            else if (eb->h_next_leaf_blk == di->i_last_eb_blk) {
511                ret = ocfs2_last_eb_is_empty(inode, di);
512                if (ret < 0) {
513                    mlog_errno(ret);
514                    goto out;
515                }
516                if (ret == 1)
517                    *is_last = 1;
518            }
519        }
520    }
521
522out_hole:
523    ret = 0;
524out:
525    brelse(eb_bh);
526    return ret;
527}
528
529static 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
544int ocfs2_xattr_get_clusters(struct inode *inode, u32 v_cluster,
545                 u32 *p_cluster, u32 *num_clusters,
546                 struct ocfs2_extent_list *el,
547                 unsigned int *extent_flags)
548{
549    int ret = 0, i;
550    struct buffer_head *eb_bh = NULL;
551    struct ocfs2_extent_block *eb;
552    struct ocfs2_extent_rec *rec;
553    u32 coff;
554
555    if (el->l_tree_depth) {
556        ret = ocfs2_find_leaf(INODE_CACHE(inode), el, v_cluster,
557                      &eb_bh);
558        if (ret) {
559            mlog_errno(ret);
560            goto out;
561        }
562
563        eb = (struct ocfs2_extent_block *) eb_bh->b_data;
564        el = &eb->h_list;
565
566        if (el->l_tree_depth) {
567            ocfs2_error(inode->i_sb,
568                    "Inode %lu has non zero tree depth in "
569                    "xattr leaf block %llu\n", inode->i_ino,
570                    (unsigned long long)eb_bh->b_blocknr);
571            ret = -EROFS;
572            goto out;
573        }
574    }
575
576    i = ocfs2_search_extent_list(el, v_cluster);
577    if (i == -1) {
578        ret = -EROFS;
579        mlog_errno(ret);
580        goto out;
581    } else {
582        rec = &el->l_recs[i];
583        BUG_ON(v_cluster < le32_to_cpu(rec->e_cpos));
584
585        if (!rec->e_blkno) {
586            ocfs2_error(inode->i_sb, "Inode %lu has bad extent "
587                    "record (%u, %u, 0) in xattr", inode->i_ino,
588                    le32_to_cpu(rec->e_cpos),
589                    ocfs2_rec_clusters(el, rec));
590            ret = -EROFS;
591            goto out;
592        }
593        coff = v_cluster - le32_to_cpu(rec->e_cpos);
594        *p_cluster = ocfs2_blocks_to_clusters(inode->i_sb,
595                            le64_to_cpu(rec->e_blkno));
596        *p_cluster = *p_cluster + coff;
597        if (num_clusters)
598            *num_clusters = ocfs2_rec_clusters(el, rec) - coff;
599
600        if (extent_flags)
601            *extent_flags = rec->e_flags;
602    }
603out:
604    if (eb_bh)
605        brelse(eb_bh);
606    return ret;
607}
608
609int ocfs2_get_clusters(struct inode *inode, u32 v_cluster,
610               u32 *p_cluster, u32 *num_clusters,
611               unsigned int *extent_flags)
612{
613    int ret;
614    unsigned int uninitialized_var(hole_len), flags = 0;
615    struct buffer_head *di_bh = NULL;
616    struct ocfs2_extent_rec rec;
617
618    if (OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL) {
619        ret = -ERANGE;
620        mlog_errno(ret);
621        goto out;
622    }
623
624    ret = ocfs2_extent_map_lookup(inode, v_cluster, p_cluster,
625                      num_clusters, extent_flags);
626    if (ret == 0)
627        goto out;
628
629    ret = ocfs2_read_inode_block(inode, &di_bh);
630    if (ret) {
631        mlog_errno(ret);
632        goto out;
633    }
634
635    ret = ocfs2_get_clusters_nocache(inode, di_bh, v_cluster, &hole_len,
636                     &rec, NULL);
637    if (ret) {
638        mlog_errno(ret);
639        goto out;
640    }
641
642    if (rec.e_blkno == 0ULL) {
643        /*
644         * A hole was found. Return some canned values that
645         * callers can key on. If asked for, num_clusters will
646         * be populated with the size of the hole.
647         */
648        *p_cluster = 0;
649        if (num_clusters) {
650            *num_clusters = hole_len;
651        }
652    } else {
653        ocfs2_relative_extent_offsets(inode->i_sb, v_cluster, &rec,
654                          p_cluster, num_clusters);
655        flags = rec.e_flags;
656
657        ocfs2_extent_map_insert_rec(inode, &rec);
658    }
659
660    if (extent_flags)
661        *extent_flags = flags;
662
663out:
664    brelse(di_bh);
665    return ret;
666}
667
668/*
669 * This expects alloc_sem to be held. The allocation cannot change at
670 * all while the map is in the process of being updated.
671 */
672int ocfs2_extent_map_get_blocks(struct inode *inode, u64 v_blkno, u64 *p_blkno,
673                u64 *ret_count, unsigned int *extent_flags)
674{
675    int ret;
676    int bpc = ocfs2_clusters_to_blocks(inode->i_sb, 1);
677    u32 cpos, num_clusters, p_cluster;
678    u64 boff = 0;
679
680    cpos = ocfs2_blocks_to_clusters(inode->i_sb, v_blkno);
681
682    ret = ocfs2_get_clusters(inode, cpos, &p_cluster, &num_clusters,
683                 extent_flags);
684    if (ret) {
685        mlog_errno(ret);
686        goto out;
687    }
688
689    /*
690     * p_cluster == 0 indicates a hole.
691     */
692    if (p_cluster) {
693        boff = ocfs2_clusters_to_blocks(inode->i_sb, p_cluster);
694        boff += (v_blkno & (u64)(bpc - 1));
695    }
696
697    *p_blkno = boff;
698
699    if (ret_count) {
700        *ret_count = ocfs2_clusters_to_blocks(inode->i_sb, num_clusters);
701        *ret_count -= v_blkno & (u64)(bpc - 1);
702    }
703
704out:
705    return ret;
706}
707
708/*
709 * The ocfs2_fiemap_inline() may be a little bit misleading, since
710 * it not only handles the fiemap for inlined files, but also deals
711 * with the fast symlink, cause they have no difference for extent
712 * mapping per se.
713 */
714static int ocfs2_fiemap_inline(struct inode *inode, struct buffer_head *di_bh,
715                   struct fiemap_extent_info *fieinfo,
716                   u64 map_start)
717{
718    int ret;
719    unsigned int id_count;
720    struct ocfs2_dinode *di;
721    u64 phys;
722    u32 flags = FIEMAP_EXTENT_DATA_INLINE|FIEMAP_EXTENT_LAST;
723    struct ocfs2_inode_info *oi = OCFS2_I(inode);
724
725    di = (struct ocfs2_dinode *)di_bh->b_data;
726    if (ocfs2_inode_is_fast_symlink(inode))
727        id_count = ocfs2_fast_symlink_chars(inode->i_sb);
728    else
729        id_count = le16_to_cpu(di->id2.i_data.id_count);
730
731    if (map_start < id_count) {
732        phys = oi->ip_blkno << inode->i_sb->s_blocksize_bits;
733        if (ocfs2_inode_is_fast_symlink(inode))
734            phys += offsetof(struct ocfs2_dinode, id2.i_symlink);
735        else
736            phys += offsetof(struct ocfs2_dinode,
737                     id2.i_data.id_data);
738
739        ret = fiemap_fill_next_extent(fieinfo, 0, phys, id_count,
740                          flags);
741        if (ret < 0)
742            return ret;
743    }
744
745    return 0;
746}
747
748#define OCFS2_FIEMAP_FLAGS (FIEMAP_FLAG_SYNC)
749
750int ocfs2_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
751         u64 map_start, u64 map_len)
752{
753    int ret, is_last;
754    u32 mapping_end, cpos;
755    unsigned int hole_size;
756    struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
757    u64 len_bytes, phys_bytes, virt_bytes;
758    struct buffer_head *di_bh = NULL;
759    struct ocfs2_extent_rec rec;
760
761    ret = fiemap_check_flags(fieinfo, OCFS2_FIEMAP_FLAGS);
762    if (ret)
763        return ret;
764
765    ret = ocfs2_inode_lock(inode, &di_bh, 0);
766    if (ret) {
767        mlog_errno(ret);
768        goto out;
769    }
770
771    down_read(&OCFS2_I(inode)->ip_alloc_sem);
772
773    /*
774     * Handle inline-data and fast symlink separately.
775     */
776    if ((OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL) ||
777        ocfs2_inode_is_fast_symlink(inode)) {
778        ret = ocfs2_fiemap_inline(inode, di_bh, fieinfo, map_start);
779        goto out_unlock;
780    }
781
782    cpos = map_start >> osb->s_clustersize_bits;
783    mapping_end = ocfs2_clusters_for_bytes(inode->i_sb,
784                           map_start + map_len);
785    mapping_end -= cpos;
786    is_last = 0;
787    while (cpos < mapping_end && !is_last) {
788        u32 fe_flags;
789
790        ret = ocfs2_get_clusters_nocache(inode, di_bh, cpos,
791                         &hole_size, &rec, &is_last);
792        if (ret) {
793            mlog_errno(ret);
794            goto out;
795        }
796
797        if (rec.e_blkno == 0ULL) {
798            cpos += hole_size;
799            continue;
800        }
801
802        fe_flags = 0;
803        if (rec.e_flags & OCFS2_EXT_UNWRITTEN)
804            fe_flags |= FIEMAP_EXTENT_UNWRITTEN;
805        if (rec.e_flags & OCFS2_EXT_REFCOUNTED)
806            fe_flags |= FIEMAP_EXTENT_SHARED;
807        if (is_last)
808            fe_flags |= FIEMAP_EXTENT_LAST;
809        len_bytes = (u64)le16_to_cpu(rec.e_leaf_clusters) << osb->s_clustersize_bits;
810        phys_bytes = le64_to_cpu(rec.e_blkno) << osb->sb->s_blocksize_bits;
811        virt_bytes = (u64)le32_to_cpu(rec.e_cpos) << osb->s_clustersize_bits;
812
813        ret = fiemap_fill_next_extent(fieinfo, virt_bytes, phys_bytes,
814                          len_bytes, fe_flags);
815        if (ret)
816            break;
817
818        cpos = le32_to_cpu(rec.e_cpos)+ le16_to_cpu(rec.e_leaf_clusters);
819    }
820
821    if (ret > 0)
822        ret = 0;
823
824out_unlock:
825    brelse(di_bh);
826
827    up_read(&OCFS2_I(inode)->ip_alloc_sem);
828
829    ocfs2_inode_unlock(inode, 0);
830out:
831
832    return ret;
833}
834
835int ocfs2_read_virt_blocks(struct inode *inode, u64 v_block, int nr,
836               struct buffer_head *bhs[], int flags,
837               int (*validate)(struct super_block *sb,
838                       struct buffer_head *bh))
839{
840    int rc = 0;
841    u64 p_block, p_count;
842    int i, count, done = 0;
843
844    mlog_entry("(inode = %p, v_block = %llu, nr = %d, bhs = %p, "
845           "flags = %x, validate = %p)\n",
846           inode, (unsigned long long)v_block, nr, bhs, flags,
847           validate);
848
849    if (((v_block + nr - 1) << inode->i_sb->s_blocksize_bits) >=
850        i_size_read(inode)) {
851        BUG_ON(!(flags & OCFS2_BH_READAHEAD));
852        goto out;
853    }
854
855    while (done < nr) {
856        down_read(&OCFS2_I(inode)->ip_alloc_sem);
857        rc = ocfs2_extent_map_get_blocks(inode, v_block + done,
858                         &p_block, &p_count, NULL);
859        up_read(&OCFS2_I(inode)->ip_alloc_sem);
860        if (rc) {
861            mlog_errno(rc);
862            break;
863        }
864
865        if (!p_block) {
866            rc = -EIO;
867            mlog(ML_ERROR,
868                 "Inode #%llu contains a hole at offset %llu\n",
869                 (unsigned long long)OCFS2_I(inode)->ip_blkno,
870                 (unsigned long long)(v_block + done) <<
871                 inode->i_sb->s_blocksize_bits);
872            break;
873        }
874
875        count = nr - done;
876        if (p_count < count)
877            count = p_count;
878
879        /*
880         * If the caller passed us bhs, they should have come
881         * from a previous readahead call to this function. Thus,
882         * they should have the right b_blocknr.
883         */
884        for (i = 0; i < count; i++) {
885            if (!bhs[done + i])
886                continue;
887            BUG_ON(bhs[done + i]->b_blocknr != (p_block + i));
888        }
889
890        rc = ocfs2_read_blocks(INODE_CACHE(inode), p_block, count,
891                       bhs + done, flags, validate);
892        if (rc) {
893            mlog_errno(rc);
894            break;
895        }
896        done += count;
897    }
898
899out:
900    mlog_exit(rc);
901    return rc;
902}
903
904
905

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