1 /*
2 * extent.c --- routines to implement extents support
3 *
4 * Copyright (C) 2007 Theodore Ts'o.
5 *
6 * %Begin-Header%
7 * This file may be redistributed under the terms of the GNU Library
8 * General Public License, version 2.
9 * %End-Header%
10 */
11
12 #include "config.h"
13 #include <stdio.h>
14 #include <string.h>
15 #if HAVE_UNISTD_H
16 #include <unistd.h>
17 #endif
18 #if HAVE_ERRNO_H
19 #include <errno.h>
20 #endif
21 #if HAVE_SYS_STAT_H
22 #include <sys/stat.h>
23 #endif
24 #if HAVE_SYS_TYPES_H
25 #include <sys/types.h>
26 #endif
27
28 #include "ext2_fs.h"
29 #include "ext2fsP.h"
30 #include "e2image.h"
31
32 #undef DEBUG
33
34 /*
35 * Definitions to be dropped in lib/ext2fs/ext2fs.h
36 */
37
38 /*
39 * Private definitions
40 */
41
42 struct extent_path {
43 char *buf;
44 int entries;
45 int max_entries;
46 int left;
47 int visit_num;
48 int flags;
49 blk64_t end_blk;
50 void *curr;
51 };
52
53
54 struct ext2_extent_handle {
55 errcode_t magic;
56 ext2_filsys fs;
57 ext2_ino_t ino;
58 struct ext2_inode *inode;
59 struct ext2_inode inodebuf;
60 int type;
61 int level;
62 int max_depth;
63 int max_paths;
64 struct extent_path *path;
65 };
66
67 struct ext2_extent_path {
68 errcode_t magic;
69 int leaf_height;
70 blk64_t lblk;
71 };
72
73 /*
74 * Useful Debugging stuff
75 */
76
77 #ifdef DEBUG
dbg_show_header(struct ext3_extent_header * eh)78 static void dbg_show_header(struct ext3_extent_header *eh)
79 {
80 printf("header: magic=%x entries=%u max=%u depth=%u generation=%u\n",
81 ext2fs_le16_to_cpu(eh->eh_magic),
82 ext2fs_le16_to_cpu(eh->eh_entries),
83 ext2fs_le16_to_cpu(eh->eh_max),
84 ext2fs_le16_to_cpu(eh->eh_depth),
85 ext2fs_le32_to_cpu(eh->eh_generation));
86 }
87
dbg_show_index(struct ext3_extent_idx * ix)88 static void dbg_show_index(struct ext3_extent_idx *ix)
89 {
90 printf("index: block=%u leaf=%u leaf_hi=%u unused=%u\n",
91 ext2fs_le32_to_cpu(ix->ei_block),
92 ext2fs_le32_to_cpu(ix->ei_leaf),
93 ext2fs_le16_to_cpu(ix->ei_leaf_hi),
94 ext2fs_le16_to_cpu(ix->ei_unused));
95 }
96
dbg_show_extent(struct ext3_extent * ex)97 static void dbg_show_extent(struct ext3_extent *ex)
98 {
99 printf("extent: block=%u-%u len=%u start=%u start_hi=%u\n",
100 ext2fs_le32_to_cpu(ex->ee_block),
101 ext2fs_le32_to_cpu(ex->ee_block) +
102 ext2fs_le16_to_cpu(ex->ee_len) - 1,
103 ext2fs_le16_to_cpu(ex->ee_len),
104 ext2fs_le32_to_cpu(ex->ee_start),
105 ext2fs_le16_to_cpu(ex->ee_start_hi));
106 }
107
dbg_print_extent(char * desc,struct ext2fs_extent * extent)108 static void dbg_print_extent(char *desc, struct ext2fs_extent *extent)
109 {
110 if (desc)
111 printf("%s: ", desc);
112 printf("extent: lblk %llu--%llu, len %u, pblk %llu, flags: ",
113 extent->e_lblk, extent->e_lblk + extent->e_len - 1,
114 extent->e_len, extent->e_pblk);
115 if (extent->e_flags & EXT2_EXTENT_FLAGS_LEAF)
116 fputs("LEAF ", stdout);
117 if (extent->e_flags & EXT2_EXTENT_FLAGS_UNINIT)
118 fputs("UNINIT ", stdout);
119 if (extent->e_flags & EXT2_EXTENT_FLAGS_SECOND_VISIT)
120 fputs("2ND_VISIT ", stdout);
121 if (!extent->e_flags)
122 fputs("(none)", stdout);
123 fputc('\n', stdout);
124
125 }
126
dump_path(const char * tag,struct ext2_extent_handle * handle,struct extent_path * path)127 static void dump_path(const char *tag, struct ext2_extent_handle *handle,
128 struct extent_path *path)
129 {
130 struct extent_path *ppp = path;
131 printf("%s: level=%d\n", tag, handle->level);
132
133 do {
134 printf("%s: path=%ld buf=%p entries=%d max_entries=%d left=%d "
135 "visit_num=%d flags=0x%x end_blk=%llu curr=%p(%ld)\n",
136 tag, (ppp - handle->path), ppp->buf, ppp->entries,
137 ppp->max_entries, ppp->left, ppp->visit_num, ppp->flags,
138 ppp->end_blk, ppp->curr, ppp->curr - (void *)ppp->buf);
139 printf(" ");
140 dbg_show_header((struct ext3_extent_header *)ppp->buf);
141 if (ppp->curr) {
142 printf(" ");
143 dbg_show_index(ppp->curr);
144 printf(" ");
145 dbg_show_extent(ppp->curr);
146 }
147 ppp--;
148 } while (ppp >= handle->path);
149 fflush(stdout);
150
151 return;
152 }
153
154 #else
155 #define dbg_show_header(eh) do { } while (0)
156 #define dbg_show_index(ix) do { } while (0)
157 #define dbg_show_extent(ex) do { } while (0)
158 #define dbg_print_extent(desc, ex) do { } while (0)
159 #define dump_path(tag, handle, path) do { } while (0)
160 #endif
161
162 /*
163 * Verify the extent header as being sane
164 */
ext2fs_extent_header_verify(void * ptr,int size)165 errcode_t ext2fs_extent_header_verify(void *ptr, int size)
166 {
167 int eh_max, entry_size;
168 struct ext3_extent_header *eh = ptr;
169
170 dbg_show_header(eh);
171 if (ext2fs_le16_to_cpu(eh->eh_magic) != EXT3_EXT_MAGIC)
172 return EXT2_ET_EXTENT_HEADER_BAD;
173 if (ext2fs_le16_to_cpu(eh->eh_entries) > ext2fs_le16_to_cpu(eh->eh_max))
174 return EXT2_ET_EXTENT_HEADER_BAD;
175 if (eh->eh_depth == 0)
176 entry_size = sizeof(struct ext3_extent);
177 else
178 entry_size = sizeof(struct ext3_extent_idx);
179
180 eh_max = (size - sizeof(*eh)) / entry_size;
181 /* Allow two extent-sized items at the end of the block, for
182 * ext4_extent_tail with checksum in the future. */
183 if ((ext2fs_le16_to_cpu(eh->eh_max) > eh_max) ||
184 (ext2fs_le16_to_cpu(eh->eh_max) < (eh_max - 2)))
185 return EXT2_ET_EXTENT_HEADER_BAD;
186
187 return 0;
188 }
189
190
191 /*
192 * Begin functions to handle an inode's extent information
193 */
ext2fs_extent_free(ext2_extent_handle_t handle)194 void ext2fs_extent_free(ext2_extent_handle_t handle)
195 {
196 int i;
197
198 if (!handle)
199 return;
200
201 if (handle->path) {
202 for (i = 1; i < handle->max_paths; i++) {
203 if (handle->path[i].buf)
204 ext2fs_free_mem(&handle->path[i].buf);
205 }
206 ext2fs_free_mem(&handle->path);
207 }
208 ext2fs_free_mem(&handle);
209 }
210
ext2fs_extent_open(ext2_filsys fs,ext2_ino_t ino,ext2_extent_handle_t * ret_handle)211 errcode_t ext2fs_extent_open(ext2_filsys fs, ext2_ino_t ino,
212 ext2_extent_handle_t *ret_handle)
213 {
214 return ext2fs_extent_open2(fs, ino, NULL, ret_handle);
215 }
216
ext2fs_extent_open2(ext2_filsys fs,ext2_ino_t ino,struct ext2_inode * inode,ext2_extent_handle_t * ret_handle)217 errcode_t ext2fs_extent_open2(ext2_filsys fs, ext2_ino_t ino,
218 struct ext2_inode *inode,
219 ext2_extent_handle_t *ret_handle)
220 {
221 struct ext2_extent_handle *handle;
222 errcode_t retval;
223 int i;
224 struct ext3_extent_header *eh;
225
226 EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
227
228 if (!inode)
229 if ((ino == 0) || (ino > fs->super->s_inodes_count))
230 return EXT2_ET_BAD_INODE_NUM;
231
232 retval = ext2fs_get_mem(sizeof(struct ext2_extent_handle), &handle);
233 if (retval)
234 return retval;
235 memset(handle, 0, sizeof(struct ext2_extent_handle));
236
237 handle->ino = ino;
238 handle->fs = fs;
239
240 if (inode) {
241 handle->inode = inode;
242 } else {
243 handle->inode = &handle->inodebuf;
244 retval = ext2fs_read_inode(fs, ino, handle->inode);
245 if (retval)
246 goto errout;
247 }
248
249 eh = (struct ext3_extent_header *) &handle->inode->i_block[0];
250
251 for (i=0; i < EXT2_N_BLOCKS; i++)
252 if (handle->inode->i_block[i])
253 break;
254 if (i >= EXT2_N_BLOCKS) {
255 eh->eh_magic = ext2fs_cpu_to_le16(EXT3_EXT_MAGIC);
256 eh->eh_depth = 0;
257 eh->eh_entries = 0;
258 i = (sizeof(handle->inode->i_block) - sizeof(*eh)) /
259 sizeof(struct ext3_extent);
260 eh->eh_max = ext2fs_cpu_to_le16(i);
261 handle->inode->i_flags |= EXT4_EXTENTS_FL;
262 }
263
264 if (!(handle->inode->i_flags & EXT4_EXTENTS_FL)) {
265 retval = EXT2_ET_INODE_NOT_EXTENT;
266 goto errout;
267 }
268
269 retval = ext2fs_extent_header_verify(eh, sizeof(handle->inode->i_block));
270 if (retval)
271 goto errout;
272
273 handle->max_depth = ext2fs_le16_to_cpu(eh->eh_depth);
274 handle->type = ext2fs_le16_to_cpu(eh->eh_magic);
275
276 handle->max_paths = handle->max_depth + 1;
277 retval = ext2fs_get_memzero(handle->max_paths *
278 sizeof(struct extent_path),
279 &handle->path);
280 handle->path[0].buf = (char *) handle->inode->i_block;
281
282 handle->path[0].left = handle->path[0].entries =
283 ext2fs_le16_to_cpu(eh->eh_entries);
284 handle->path[0].max_entries = ext2fs_le16_to_cpu(eh->eh_max);
285 handle->path[0].curr = 0;
286 handle->path[0].end_blk =
287 (EXT2_I_SIZE(handle->inode) + fs->blocksize - 1) >>
288 EXT2_BLOCK_SIZE_BITS(fs->super);
289 handle->path[0].visit_num = 1;
290 handle->level = 0;
291 handle->magic = EXT2_ET_MAGIC_EXTENT_HANDLE;
292
293 *ret_handle = handle;
294 return 0;
295
296 errout:
297 ext2fs_extent_free(handle);
298 return retval;
299 }
300
301 /*
302 * This function is responsible for (optionally) moving through the
303 * extent tree and then returning the current extent
304 */
ext2fs_extent_get(ext2_extent_handle_t handle,int flags,struct ext2fs_extent * extent)305 errcode_t ext2fs_extent_get(ext2_extent_handle_t handle,
306 int flags, struct ext2fs_extent *extent)
307 {
308 struct extent_path *path, *newpath;
309 struct ext3_extent_header *eh;
310 struct ext3_extent_idx *ix = 0;
311 struct ext3_extent *ex;
312 errcode_t retval;
313 blk64_t blk;
314 blk64_t end_blk;
315 int orig_op, op;
316 int failed_csum = 0;
317
318 EXT2_CHECK_MAGIC(handle, EXT2_ET_MAGIC_EXTENT_HANDLE);
319
320 if (!handle->path)
321 return EXT2_ET_NO_CURRENT_NODE;
322
323 orig_op = op = flags & EXT2_EXTENT_MOVE_MASK;
324
325 retry:
326 path = handle->path + handle->level;
327 if ((orig_op == EXT2_EXTENT_NEXT) ||
328 (orig_op == EXT2_EXTENT_NEXT_LEAF)) {
329 if (handle->level < handle->max_depth) {
330 /* interior node */
331 if (path->visit_num == 0) {
332 path->visit_num++;
333 op = EXT2_EXTENT_DOWN;
334 } else if (path->left > 0)
335 op = EXT2_EXTENT_NEXT_SIB;
336 else if (handle->level > 0)
337 op = EXT2_EXTENT_UP;
338 else
339 return EXT2_ET_EXTENT_NO_NEXT;
340 } else {
341 /* leaf node */
342 if (path->left > 0)
343 op = EXT2_EXTENT_NEXT_SIB;
344 else if (handle->level > 0)
345 op = EXT2_EXTENT_UP;
346 else
347 return EXT2_ET_EXTENT_NO_NEXT;
348 }
349 if (op != EXT2_EXTENT_NEXT_SIB) {
350 #ifdef DEBUG_GET_EXTENT
351 printf("<<<< OP = %s\n",
352 (op == EXT2_EXTENT_DOWN) ? "down" :
353 ((op == EXT2_EXTENT_UP) ? "up" : "unknown"));
354 #endif
355 }
356 }
357
358 if ((orig_op == EXT2_EXTENT_PREV) ||
359 (orig_op == EXT2_EXTENT_PREV_LEAF)) {
360 if (handle->level < handle->max_depth) {
361 /* interior node */
362 if (path->visit_num > 0 ) {
363 /* path->visit_num = 0; */
364 op = EXT2_EXTENT_DOWN_AND_LAST;
365 } else if (path->left < path->entries-1)
366 op = EXT2_EXTENT_PREV_SIB;
367 else if (handle->level > 0)
368 op = EXT2_EXTENT_UP;
369 else
370 return EXT2_ET_EXTENT_NO_PREV;
371 } else {
372 /* leaf node */
373 if (path->left < path->entries-1)
374 op = EXT2_EXTENT_PREV_SIB;
375 else if (handle->level > 0)
376 op = EXT2_EXTENT_UP;
377 else
378 return EXT2_ET_EXTENT_NO_PREV;
379 }
380 if (op != EXT2_EXTENT_PREV_SIB) {
381 #ifdef DEBUG_GET_EXTENT
382 printf("<<<< OP = %s\n",
383 (op == EXT2_EXTENT_DOWN_AND_LAST) ? "down/last" :
384 ((op == EXT2_EXTENT_UP) ? "up" : "unknown"));
385 #endif
386 }
387 }
388
389 if (orig_op == EXT2_EXTENT_LAST_LEAF) {
390 if ((handle->level < handle->max_depth) &&
391 (path->left == 0))
392 op = EXT2_EXTENT_DOWN;
393 else
394 op = EXT2_EXTENT_LAST_SIB;
395 #ifdef DEBUG_GET_EXTENT
396 printf("<<<< OP = %s\n",
397 (op == EXT2_EXTENT_DOWN) ? "down" : "last_sib");
398 #endif
399 }
400
401 switch (op) {
402 case EXT2_EXTENT_CURRENT:
403 ix = path->curr;
404 break;
405 case EXT2_EXTENT_ROOT:
406 handle->level = 0;
407 path = handle->path + handle->level;
408 /* fallthrough */
409 case EXT2_EXTENT_FIRST_SIB:
410 path->left = path->entries;
411 path->curr = 0;
412 /* fallthrough */
413 case EXT2_EXTENT_NEXT_SIB:
414 if (path->left <= 0)
415 return EXT2_ET_EXTENT_NO_NEXT;
416 if (path->curr) {
417 ix = path->curr;
418 ix++;
419 } else {
420 eh = (struct ext3_extent_header *) path->buf;
421 ix = EXT_FIRST_INDEX(eh);
422 }
423 path->left--;
424 path->curr = ix;
425 path->visit_num = 0;
426 break;
427 case EXT2_EXTENT_PREV_SIB:
428 if (!path->curr ||
429 path->left+1 >= path->entries)
430 return EXT2_ET_EXTENT_NO_PREV;
431 ix = path->curr;
432 ix--;
433 path->curr = ix;
434 path->left++;
435 if (handle->level < handle->max_depth)
436 path->visit_num = 1;
437 break;
438 case EXT2_EXTENT_LAST_SIB:
439 eh = (struct ext3_extent_header *) path->buf;
440 path->curr = EXT_LAST_EXTENT(eh);
441 ix = path->curr;
442 path->left = 0;
443 path->visit_num = 0;
444 break;
445 case EXT2_EXTENT_UP:
446 if (handle->level <= 0)
447 return EXT2_ET_EXTENT_NO_UP;
448 handle->level--;
449 path--;
450 ix = path->curr;
451 if ((orig_op == EXT2_EXTENT_PREV) ||
452 (orig_op == EXT2_EXTENT_PREV_LEAF))
453 path->visit_num = 0;
454 break;
455 case EXT2_EXTENT_DOWN:
456 case EXT2_EXTENT_DOWN_AND_LAST:
457 if (!path->curr ||(handle->level >= handle->max_depth))
458 return EXT2_ET_EXTENT_NO_DOWN;
459
460 ix = path->curr;
461 newpath = path + 1;
462 if (!newpath->buf) {
463 retval = ext2fs_get_mem(handle->fs->blocksize,
464 &newpath->buf);
465 if (retval)
466 return retval;
467 }
468 blk = ext2fs_le32_to_cpu(ix->ei_leaf) +
469 ((__u64) ext2fs_le16_to_cpu(ix->ei_leaf_hi) << 32);
470 if ((handle->fs->flags & EXT2_FLAG_IMAGE_FILE) &&
471 (handle->fs->io != handle->fs->image_io))
472 memset(newpath->buf, 0, handle->fs->blocksize);
473 else {
474 retval = io_channel_read_blk64(handle->fs->io,
475 blk, 1, newpath->buf);
476 if (retval)
477 return retval;
478 }
479 handle->level++;
480
481 eh = (struct ext3_extent_header *) newpath->buf;
482
483 retval = ext2fs_extent_header_verify(eh, handle->fs->blocksize);
484 if (retval) {
485 handle->level--;
486 return retval;
487 }
488
489 if (!(handle->fs->flags & EXT2_FLAG_IGNORE_CSUM_ERRORS) &&
490 !ext2fs_extent_block_csum_verify(handle->fs, handle->ino,
491 eh))
492 failed_csum = 1;
493
494 newpath->left = newpath->entries =
495 ext2fs_le16_to_cpu(eh->eh_entries);
496 newpath->max_entries = ext2fs_le16_to_cpu(eh->eh_max);
497
498 if (path->left > 0) {
499 ix++;
500 newpath->end_blk = ext2fs_le32_to_cpu(ix->ei_block);
501 } else
502 newpath->end_blk = path->end_blk;
503
504 path = newpath;
505 if (op == EXT2_EXTENT_DOWN) {
506 ix = EXT_FIRST_INDEX((struct ext3_extent_header *) eh);
507 path->curr = ix;
508 path->left = path->entries - 1;
509 path->visit_num = 0;
510 } else {
511 ix = EXT_LAST_INDEX((struct ext3_extent_header *) eh);
512 path->curr = ix;
513 path->left = 0;
514 if (handle->level < handle->max_depth)
515 path->visit_num = 1;
516 }
517 #ifdef DEBUG_GET_EXTENT
518 printf("Down to level %d/%d, end_blk=%llu\n",
519 handle->level, handle->max_depth,
520 path->end_blk);
521 #endif
522 break;
523 default:
524 return EXT2_ET_OP_NOT_SUPPORTED;
525 }
526
527 if (!ix)
528 return EXT2_ET_NO_CURRENT_NODE;
529
530 extent->e_flags = 0;
531 #ifdef DEBUG_GET_EXTENT
532 printf("(Left %d)\n", path->left);
533 #endif
534
535 if (handle->level == handle->max_depth) {
536 ex = (struct ext3_extent *) ix;
537
538 extent->e_pblk = ext2fs_le32_to_cpu(ex->ee_start) +
539 ((__u64) ext2fs_le16_to_cpu(ex->ee_start_hi) << 32);
540 extent->e_lblk = ext2fs_le32_to_cpu(ex->ee_block);
541 extent->e_len = ext2fs_le16_to_cpu(ex->ee_len);
542 extent->e_flags |= EXT2_EXTENT_FLAGS_LEAF;
543 if (extent->e_len > EXT_INIT_MAX_LEN) {
544 extent->e_len -= EXT_INIT_MAX_LEN;
545 extent->e_flags |= EXT2_EXTENT_FLAGS_UNINIT;
546 }
547 } else {
548 extent->e_pblk = ext2fs_le32_to_cpu(ix->ei_leaf) +
549 ((__u64) ext2fs_le16_to_cpu(ix->ei_leaf_hi) << 32);
550 extent->e_lblk = ext2fs_le32_to_cpu(ix->ei_block);
551 if (path->left > 0) {
552 ix++;
553 end_blk = ext2fs_le32_to_cpu(ix->ei_block);
554 } else
555 end_blk = path->end_blk;
556
557 extent->e_len = end_blk - extent->e_lblk;
558 }
559 if (path->visit_num)
560 extent->e_flags |= EXT2_EXTENT_FLAGS_SECOND_VISIT;
561
562 if (((orig_op == EXT2_EXTENT_NEXT_LEAF) ||
563 (orig_op == EXT2_EXTENT_PREV_LEAF)) &&
564 (handle->level != handle->max_depth))
565 goto retry;
566
567 if ((orig_op == EXT2_EXTENT_LAST_LEAF) &&
568 ((handle->level != handle->max_depth) ||
569 (path->left != 0)))
570 goto retry;
571
572 if (failed_csum)
573 return EXT2_ET_EXTENT_CSUM_INVALID;
574
575 return 0;
576 }
577
update_path(ext2_extent_handle_t handle)578 static errcode_t update_path(ext2_extent_handle_t handle)
579 {
580 blk64_t blk;
581 errcode_t retval;
582 struct ext3_extent_idx *ix;
583 struct ext3_extent_header *eh;
584
585 if (handle->level == 0) {
586 retval = ext2fs_write_inode(handle->fs, handle->ino,
587 handle->inode);
588 } else {
589 ix = handle->path[handle->level - 1].curr;
590 blk = ext2fs_le32_to_cpu(ix->ei_leaf) +
591 ((__u64) ext2fs_le16_to_cpu(ix->ei_leaf_hi) << 32);
592
593 /* then update the checksum */
594 eh = (struct ext3_extent_header *)
595 handle->path[handle->level].buf;
596 retval = ext2fs_extent_block_csum_set(handle->fs, handle->ino,
597 eh);
598 if (retval)
599 return retval;
600
601 retval = io_channel_write_blk64(handle->fs->io,
602 blk, 1, handle->path[handle->level].buf);
603 }
604 return retval;
605 }
606
607 #if 0
608 errcode_t ext2fs_extent_save_path(ext2_extent_handle_t handle,
609 ext2_extent_path_t *ret_path)
610 {
611 ext2_extent_path_t save_path;
612 struct ext2fs_extent extent;
613 struct ext2_extent_info info;
614 errcode_t retval;
615
616 retval = ext2fs_extent_get(handle, EXT2_EXTENT_CURRENT, &extent);
617 if (retval)
618 return retval;
619
620 retval = ext2fs_extent_get_info(handle, &info);
621 if (retval)
622 return retval;
623
624 retval = ext2fs_get_mem(sizeof(struct ext2_extent_path), &save_path);
625 if (retval)
626 return retval;
627 memset(save_path, 0, sizeof(struct ext2_extent_path));
628
629 save_path->magic = EXT2_ET_MAGIC_EXTENT_PATH;
630 save_path->leaf_height = info.max_depth - info.curr_level - 1;
631 save_path->lblk = extent.e_lblk;
632
633 *ret_path = save_path;
634 return 0;
635 }
636
637 errcode_t ext2fs_extent_free_path(ext2_extent_path_t path)
638 {
639 EXT2_CHECK_MAGIC(path, EXT2_ET_MAGIC_EXTENT_PATH);
640
641 ext2fs_free_mem(&path);
642 return 0;
643 }
644 #endif
645
646 /*
647 * Go to the node at leaf_level which contains logical block blk.
648 *
649 * leaf_level is height from the leaf node level, i.e.
650 * leaf_level 0 is at leaf node, leaf_level 1 is 1 above etc.
651 *
652 * If "blk" has no mapping (hole) then handle is left at last
653 * extent before blk.
654 */
ext2fs_extent_goto2(ext2_extent_handle_t handle,int leaf_level,blk64_t blk)655 errcode_t ext2fs_extent_goto2(ext2_extent_handle_t handle,
656 int leaf_level, blk64_t blk)
657 {
658 struct ext2fs_extent extent;
659 errcode_t retval;
660
661 retval = ext2fs_extent_get(handle, EXT2_EXTENT_ROOT, &extent);
662 if (retval) {
663 if (retval == EXT2_ET_EXTENT_NO_NEXT)
664 retval = EXT2_ET_EXTENT_NOT_FOUND;
665 return retval;
666 }
667
668 if (leaf_level > handle->max_depth) {
669 #ifdef DEBUG
670 printf("leaf level %d greater than tree depth %d\n",
671 leaf_level, handle->max_depth);
672 #endif
673 return EXT2_ET_OP_NOT_SUPPORTED;
674 }
675
676 #ifdef DEBUG
677 printf("goto extent ino %u, level %d, %llu\n", handle->ino,
678 leaf_level, blk);
679 #endif
680
681 #ifdef DEBUG_GOTO_EXTENTS
682 dbg_print_extent("root", &extent);
683 #endif
684 while (1) {
685 if (handle->max_depth - handle->level == leaf_level) {
686 /* block is in this &extent */
687 if ((blk >= extent.e_lblk) &&
688 (blk < extent.e_lblk + extent.e_len))
689 return 0;
690 if (blk < extent.e_lblk) {
691 retval = ext2fs_extent_get(handle,
692 EXT2_EXTENT_PREV_SIB,
693 &extent);
694 return EXT2_ET_EXTENT_NOT_FOUND;
695 }
696 retval = ext2fs_extent_get(handle,
697 EXT2_EXTENT_NEXT_SIB,
698 &extent);
699 if (retval == EXT2_ET_EXTENT_NO_NEXT)
700 return EXT2_ET_EXTENT_NOT_FOUND;
701 if (retval)
702 return retval;
703 continue;
704 }
705
706 retval = ext2fs_extent_get(handle, EXT2_EXTENT_NEXT_SIB,
707 &extent);
708 if (retval == EXT2_ET_EXTENT_NO_NEXT)
709 goto go_down;
710 if (retval)
711 return retval;
712
713 #ifdef DEBUG_GOTO_EXTENTS
714 dbg_print_extent("next", &extent);
715 #endif
716 if (blk == extent.e_lblk)
717 goto go_down;
718 if (blk > extent.e_lblk)
719 continue;
720
721 retval = ext2fs_extent_get(handle, EXT2_EXTENT_PREV_SIB,
722 &extent);
723 if (retval)
724 return retval;
725
726 #ifdef DEBUG_GOTO_EXTENTS
727 dbg_print_extent("prev", &extent);
728 #endif
729
730 go_down:
731 retval = ext2fs_extent_get(handle, EXT2_EXTENT_DOWN,
732 &extent);
733 if (retval)
734 return retval;
735
736 #ifdef DEBUG_GOTO_EXTENTS
737 dbg_print_extent("down", &extent);
738 #endif
739 }
740 }
741
ext2fs_extent_goto(ext2_extent_handle_t handle,blk64_t blk)742 errcode_t ext2fs_extent_goto(ext2_extent_handle_t handle,
743 blk64_t blk)
744 {
745 return ext2fs_extent_goto2(handle, 0, blk);
746 }
747
748 /*
749 * Traverse back up to root fixing parents of current node as needed.
750 *
751 * If we changed start of first entry in a node, fix parent index start
752 * and so on.
753 *
754 * Safe to call for any position in node; if not at the first entry,
755 * it will simply return.
756 *
757 * Note a subtlety of this function -- if there happen to be two extents
758 * mapping the same lblk and someone calls fix_parents on the second of the two
759 * extents, the position of the extent handle after the call will be the second
760 * extent if nothing happened, or the first extent if something did. A caller
761 * in this situation must use ext2fs_extent_goto() after calling this function.
762 * Or simply don't map the same lblk with two extents, ever.
763 */
ext2fs_extent_fix_parents(ext2_extent_handle_t handle)764 errcode_t ext2fs_extent_fix_parents(ext2_extent_handle_t handle)
765 {
766 int retval = 0;
767 int orig_height;
768 blk64_t start;
769 struct extent_path *path;
770 struct ext2fs_extent extent;
771 struct ext2_extent_info info;
772
773 EXT2_CHECK_MAGIC(handle, EXT2_ET_MAGIC_EXTENT_HANDLE);
774
775 if (!(handle->fs->flags & EXT2_FLAG_RW))
776 return EXT2_ET_RO_FILSYS;
777
778 if (!handle->path)
779 return EXT2_ET_NO_CURRENT_NODE;
780
781 path = handle->path + handle->level;
782 if (!path->curr)
783 return EXT2_ET_NO_CURRENT_NODE;
784
785 retval = ext2fs_extent_get(handle, EXT2_EXTENT_CURRENT, &extent);
786 if (retval)
787 goto done;
788
789 /* modified node's start block */
790 start = extent.e_lblk;
791
792 if ((retval = ext2fs_extent_get_info(handle, &info)))
793 return retval;
794 orig_height = info.max_depth - info.curr_level;
795
796 /* traverse up until index not first, or startblk matches, or top */
797 while (handle->level > 0 &&
798 (path->left == path->entries - 1)) {
799 retval = ext2fs_extent_get(handle, EXT2_EXTENT_UP, &extent);
800 if (retval)
801 goto done;
802 if (extent.e_lblk == start)
803 break;
804 path = handle->path + handle->level;
805 extent.e_len += (extent.e_lblk - start);
806 extent.e_lblk = start;
807 retval = ext2fs_extent_replace(handle, 0, &extent);
808 if (retval)
809 goto done;
810 update_path(handle);
811 }
812
813 /* put handle back to where we started */
814 retval = ext2fs_extent_goto2(handle, orig_height, start);
815 done:
816 return retval;
817 }
818
ext2fs_extent_replace(ext2_extent_handle_t handle,int flags EXT2FS_ATTR ((unused)),struct ext2fs_extent * extent)819 errcode_t ext2fs_extent_replace(ext2_extent_handle_t handle,
820 int flags EXT2FS_ATTR((unused)),
821 struct ext2fs_extent *extent)
822 {
823 struct extent_path *path;
824 struct ext3_extent_idx *ix;
825 struct ext3_extent *ex;
826
827 EXT2_CHECK_MAGIC(handle, EXT2_ET_MAGIC_EXTENT_HANDLE);
828
829 if (!(handle->fs->flags & EXT2_FLAG_RW))
830 return EXT2_ET_RO_FILSYS;
831
832 if (!handle->path)
833 return EXT2_ET_NO_CURRENT_NODE;
834
835 path = handle->path + handle->level;
836 if (!path->curr)
837 return EXT2_ET_NO_CURRENT_NODE;
838
839 #ifdef DEBUG
840 printf("extent replace: %u ", handle->ino);
841 dbg_print_extent(0, extent);
842 #endif
843
844 if (handle->level == handle->max_depth) {
845 ex = path->curr;
846
847 ex->ee_block = ext2fs_cpu_to_le32(extent->e_lblk);
848 ex->ee_start = ext2fs_cpu_to_le32(extent->e_pblk & 0xFFFFFFFF);
849 ex->ee_start_hi = ext2fs_cpu_to_le16(extent->e_pblk >> 32);
850 if (extent->e_flags & EXT2_EXTENT_FLAGS_UNINIT) {
851 if (extent->e_len > EXT_UNINIT_MAX_LEN)
852 return EXT2_ET_EXTENT_INVALID_LENGTH;
853 ex->ee_len = ext2fs_cpu_to_le16(extent->e_len +
854 EXT_INIT_MAX_LEN);
855 } else {
856 if (extent->e_len > EXT_INIT_MAX_LEN)
857 return EXT2_ET_EXTENT_INVALID_LENGTH;
858 ex->ee_len = ext2fs_cpu_to_le16(extent->e_len);
859 }
860 } else {
861 ix = path->curr;
862
863 ix->ei_leaf = ext2fs_cpu_to_le32(extent->e_pblk & 0xFFFFFFFF);
864 ix->ei_leaf_hi = ext2fs_cpu_to_le16(extent->e_pblk >> 32);
865 ix->ei_block = ext2fs_cpu_to_le32(extent->e_lblk);
866 ix->ei_unused = 0;
867 }
868 update_path(handle);
869 return 0;
870 }
871
splitting_at_eof(struct ext2_extent_handle * handle,struct extent_path * path)872 static int splitting_at_eof(struct ext2_extent_handle *handle,
873 struct extent_path *path)
874 {
875 struct extent_path *ppp = path;
876 dump_path(__func__, handle, path);
877
878 if (handle->level == 0)
879 return 0;
880
881 do {
882 if (ppp->left)
883 return 0;
884 ppp--;
885 } while (ppp >= handle->path);
886
887 return 1;
888 }
889
890 /*
891 * allocate a new block, move half the current node to it, and update parent
892 *
893 * handle will be left pointing at original record.
894 */
extent_node_split(ext2_extent_handle_t handle,int expand_allowed)895 static errcode_t extent_node_split(ext2_extent_handle_t handle,
896 int expand_allowed)
897 {
898 errcode_t retval = 0;
899 blk64_t new_node_pblk;
900 blk64_t new_node_start;
901 blk64_t orig_lblk;
902 blk64_t goal_blk = 0;
903 int orig_height;
904 char *block_buf = NULL;
905 struct ext2fs_extent extent;
906 struct extent_path *path, *newpath = 0;
907 struct ext3_extent_header *eh, *neweh;
908 int tocopy;
909 int new_root = 0;
910 struct ext2_extent_info info;
911 int no_balance;
912
913 /* basic sanity */
914 EXT2_CHECK_MAGIC(handle, EXT2_ET_MAGIC_EXTENT_HANDLE);
915
916 if (!(handle->fs->flags & EXT2_FLAG_RW))
917 return EXT2_ET_RO_FILSYS;
918
919 if (!handle->path)
920 return EXT2_ET_NO_CURRENT_NODE;
921
922 #ifdef DEBUG
923 printf("splitting node at level %d\n", handle->level);
924 #endif
925 retval = ext2fs_extent_get(handle, EXT2_EXTENT_CURRENT, &extent);
926 if (retval)
927 goto done;
928
929 retval = ext2fs_extent_get_info(handle, &info);
930 if (retval)
931 goto done;
932
933 /* save the position we were originally splitting... */
934 orig_height = info.max_depth - info.curr_level;
935 orig_lblk = extent.e_lblk;
936
937 /* Try to put the index block before the first extent */
938 path = handle->path + handle->level;
939 eh = (struct ext3_extent_header *) path->buf;
940 if (handle->level == handle->max_depth) {
941 struct ext3_extent *ex;
942
943 ex = EXT_FIRST_EXTENT(eh);
944 goal_blk = ext2fs_le32_to_cpu(ex->ee_start) +
945 ((__u64) ext2fs_le16_to_cpu(ex->ee_start_hi) << 32);
946 } else {
947 struct ext3_extent_idx *ix;
948
949 ix = EXT_FIRST_INDEX(eh);
950 goal_blk = ext2fs_le32_to_cpu(ix->ei_leaf) +
951 ((__u64) ext2fs_le16_to_cpu(ix->ei_leaf_hi) << 32);
952 }
953 goal_blk -= EXT2FS_CLUSTER_RATIO(handle->fs);
954 goal_blk &= ~EXT2FS_CLUSTER_MASK(handle->fs);
955
956 /* Is there room in the parent for a new entry? */
957 if (handle->level &&
958 (handle->path[handle->level - 1].entries >=
959 handle->path[handle->level - 1].max_entries)) {
960
961 #ifdef DEBUG
962 printf("parent level %d full; splitting it too\n",
963 handle->level - 1);
964 #endif
965 /* split the parent */
966 retval = ext2fs_extent_get(handle, EXT2_EXTENT_UP, &extent);
967 if (retval)
968 goto done;
969
970 retval = extent_node_split(handle, expand_allowed);
971 if (retval)
972 goto done;
973
974 /* get handle back to our original split position */
975 retval = ext2fs_extent_goto2(handle, orig_height, orig_lblk);
976 if (retval)
977 goto done;
978 }
979
980 /* At this point, parent should have room for this split */
981 path = handle->path + handle->level;
982 if (!path->curr)
983 return EXT2_ET_NO_CURRENT_NODE;
984
985 /*
986 * Normally, we try to split a full node in half. This doesn't turn
987 * out so well if we're tacking extents on the end of the file because
988 * then we're stuck with a tree of half-full extent blocks. This of
989 * course doesn't apply to the root level.
990 */
991 no_balance = expand_allowed ? splitting_at_eof(handle, path) : 0;
992
993 /* extent header of the current node we'll split */
994 eh = (struct ext3_extent_header *)path->buf;
995
996 /* splitting root level means moving them all out */
997 if (handle->level == 0) {
998 new_root = 1;
999 tocopy = ext2fs_le16_to_cpu(eh->eh_entries);
1000 retval = ext2fs_get_memzero((handle->max_paths + 1) *
1001 sizeof(struct extent_path),
1002 &newpath);
1003 if (retval)
1004 goto done;
1005 } else {
1006 if (no_balance)
1007 tocopy = 1;
1008 else
1009 tocopy = ext2fs_le16_to_cpu(eh->eh_entries) / 2;
1010 }
1011
1012 #ifdef DEBUG
1013 printf("will copy out %d of %d entries at level %d\n",
1014 tocopy, ext2fs_le16_to_cpu(eh->eh_entries),
1015 handle->level);
1016 #endif
1017
1018 if (!tocopy && !no_balance) {
1019 #ifdef DEBUG
1020 printf("Nothing to copy to new block!\n");
1021 #endif
1022 retval = EXT2_ET_CANT_SPLIT_EXTENT;
1023 goto done;
1024 }
1025
1026 /* first we need a new block, or can do nothing. */
1027 block_buf = malloc(handle->fs->blocksize);
1028 if (!block_buf) {
1029 retval = ENOMEM;
1030 goto done;
1031 }
1032
1033 if (!goal_blk)
1034 goal_blk = ext2fs_find_inode_goal(handle->fs, handle->ino,
1035 handle->inode, 0);
1036 retval = ext2fs_alloc_block2(handle->fs, goal_blk, block_buf,
1037 &new_node_pblk);
1038 if (retval)
1039 goto done;
1040
1041 #ifdef DEBUG
1042 printf("will copy to new node at block %lu\n",
1043 (unsigned long) new_node_pblk);
1044 #endif
1045
1046 /* Copy data into new block buffer */
1047 /* First the header for the new block... */
1048 neweh = (struct ext3_extent_header *) block_buf;
1049 memcpy(neweh, eh, sizeof(struct ext3_extent_header));
1050 neweh->eh_entries = ext2fs_cpu_to_le16(tocopy);
1051 neweh->eh_max = ext2fs_cpu_to_le16((handle->fs->blocksize -
1052 sizeof(struct ext3_extent_header)) /
1053 sizeof(struct ext3_extent));
1054
1055 /* then the entries for the new block... */
1056 memcpy(EXT_FIRST_INDEX(neweh),
1057 EXT_FIRST_INDEX(eh) +
1058 (ext2fs_le16_to_cpu(eh->eh_entries) - tocopy),
1059 sizeof(struct ext3_extent_idx) * tocopy);
1060
1061 new_node_start = ext2fs_le32_to_cpu(EXT_FIRST_INDEX(neweh)->ei_block);
1062
1063 /* then update the checksum */
1064 retval = ext2fs_extent_block_csum_set(handle->fs, handle->ino, neweh);
1065 if (retval)
1066 goto done;
1067
1068 /* ...and write the new node block out to disk. */
1069 retval = io_channel_write_blk64(handle->fs->io, new_node_pblk, 1,
1070 block_buf);
1071
1072 if (retval)
1073 goto done;
1074
1075 /* OK! we've created the new node; now adjust the tree */
1076
1077 /* current path now has fewer active entries, we copied some out */
1078 if (handle->level == 0) {
1079 memcpy(newpath, path,
1080 sizeof(struct extent_path) * handle->max_paths);
1081 handle->path = newpath;
1082 newpath = path;
1083 path = handle->path;
1084 path->entries = 1;
1085 path->left = path->max_entries - 1;
1086 handle->max_depth++;
1087 handle->max_paths++;
1088 eh->eh_depth = ext2fs_cpu_to_le16(handle->max_depth);
1089 } else {
1090 path->entries -= tocopy;
1091 path->left -= tocopy;
1092 }
1093
1094 eh->eh_entries = ext2fs_cpu_to_le16(path->entries);
1095 /* this writes out the node, incl. the modified header */
1096 retval = update_path(handle);
1097 if (retval)
1098 goto done;
1099
1100 /* now go up and insert/replace index for new node we created */
1101 if (new_root) {
1102 retval = ext2fs_extent_get(handle, EXT2_EXTENT_FIRST_SIB, &extent);
1103 if (retval)
1104 goto done;
1105
1106 extent.e_lblk = new_node_start;
1107 extent.e_pblk = new_node_pblk;
1108 extent.e_len = handle->path[0].end_blk - extent.e_lblk;
1109 retval = ext2fs_extent_replace(handle, 0, &extent);
1110 if (retval)
1111 goto done;
1112 } else {
1113 __u32 new_node_length;
1114
1115 retval = ext2fs_extent_get(handle, EXT2_EXTENT_UP, &extent);
1116 /* will insert after this one; it's length is shorter now */
1117 new_node_length = new_node_start - extent.e_lblk;
1118 extent.e_len -= new_node_length;
1119 retval = ext2fs_extent_replace(handle, 0, &extent);
1120 if (retval)
1121 goto done;
1122
1123 /* now set up the new extent and insert it */
1124 extent.e_lblk = new_node_start;
1125 extent.e_pblk = new_node_pblk;
1126 extent.e_len = new_node_length;
1127 retval = ext2fs_extent_insert(handle, EXT2_EXTENT_INSERT_AFTER, &extent);
1128 if (retval)
1129 goto done;
1130 }
1131
1132 /* get handle back to our original position */
1133 retval = ext2fs_extent_goto2(handle, orig_height, orig_lblk);
1134 if (retval)
1135 goto done;
1136
1137 /* new node hooked in, so update inode block count (do this here?) */
1138 ext2fs_iblk_add_blocks(handle->fs, handle->inode, 1);
1139 retval = ext2fs_write_inode(handle->fs, handle->ino,
1140 handle->inode);
1141 if (retval)
1142 goto done;
1143
1144 done:
1145 if (newpath)
1146 ext2fs_free_mem(&newpath);
1147 free(block_buf);
1148
1149 return retval;
1150 }
1151
ext2fs_extent_node_split(ext2_extent_handle_t handle)1152 errcode_t ext2fs_extent_node_split(ext2_extent_handle_t handle)
1153 {
1154 return extent_node_split(handle, 0);
1155 }
1156
ext2fs_extent_insert(ext2_extent_handle_t handle,int flags,struct ext2fs_extent * extent)1157 errcode_t ext2fs_extent_insert(ext2_extent_handle_t handle, int flags,
1158 struct ext2fs_extent *extent)
1159 {
1160 struct extent_path *path;
1161 struct ext3_extent_idx *ix;
1162 struct ext3_extent_header *eh;
1163 errcode_t retval;
1164
1165 EXT2_CHECK_MAGIC(handle, EXT2_ET_MAGIC_EXTENT_HANDLE);
1166
1167 if (!(handle->fs->flags & EXT2_FLAG_RW))
1168 return EXT2_ET_RO_FILSYS;
1169
1170 if (!handle->path)
1171 return EXT2_ET_NO_CURRENT_NODE;
1172
1173 #ifdef DEBUG
1174 printf("extent insert: %u ", handle->ino);
1175 dbg_print_extent(0, extent);
1176 #endif
1177
1178 path = handle->path + handle->level;
1179
1180 if (path->entries >= path->max_entries) {
1181 if (flags & EXT2_EXTENT_INSERT_NOSPLIT) {
1182 return EXT2_ET_CANT_INSERT_EXTENT;
1183 } else {
1184 #ifdef DEBUG
1185 printf("node full (level %d) - splitting\n",
1186 handle->level);
1187 #endif
1188 retval = extent_node_split(handle, 1);
1189 if (retval)
1190 return retval;
1191 path = handle->path + handle->level;
1192 }
1193 }
1194
1195 eh = (struct ext3_extent_header *) path->buf;
1196 if (path->curr) {
1197 ix = path->curr;
1198 if (flags & EXT2_EXTENT_INSERT_AFTER) {
1199 ix++;
1200 path->left--;
1201 }
1202 } else {
1203 ix = EXT_FIRST_INDEX(eh);
1204 path->left = -1;
1205 }
1206
1207 path->curr = ix;
1208
1209 if (path->left >= 0)
1210 memmove(ix + 1, ix,
1211 (path->left+1) * sizeof(struct ext3_extent_idx));
1212 path->left++;
1213 path->entries++;
1214
1215 eh = (struct ext3_extent_header *) path->buf;
1216 eh->eh_entries = ext2fs_cpu_to_le16(path->entries);
1217
1218 retval = ext2fs_extent_replace(handle, 0, extent);
1219 if (retval)
1220 goto errout;
1221
1222 retval = update_path(handle);
1223 if (retval)
1224 goto errout;
1225
1226 return 0;
1227
1228 errout:
1229 ext2fs_extent_delete(handle, 0);
1230 return retval;
1231 }
1232
1233 /*
1234 * Sets the physical block for a logical file block in the extent tree.
1235 *
1236 * May: map unmapped, unmap mapped, or remap mapped blocks.
1237 *
1238 * Mapping an unmapped block adds a single-block extent.
1239 *
1240 * Unmapping first or last block modifies extent in-place
1241 * - But may need to fix parent's starts too in first-block case
1242 *
1243 * Mapping any unmapped block requires adding a (single-block) extent
1244 * and inserting into proper point in tree.
1245 *
1246 * Modifying (unmapping or remapping) a block in the middle
1247 * of an extent requires splitting the extent.
1248 * - Remapping case requires new single-block extent.
1249 *
1250 * Remapping first or last block adds an extent.
1251 *
1252 * We really need extent adding to be smart about merging.
1253 */
1254
ext2fs_extent_set_bmap(ext2_extent_handle_t handle,blk64_t logical,blk64_t physical,int flags)1255 errcode_t ext2fs_extent_set_bmap(ext2_extent_handle_t handle,
1256 blk64_t logical, blk64_t physical, int flags)
1257 {
1258 errcode_t ec, retval = 0;
1259 int mapped = 1; /* logical is mapped? */
1260 int orig_height;
1261 int extent_uninit = 0;
1262 int prev_uninit = 0;
1263 int next_uninit = 0;
1264 int new_uninit = 0;
1265 int max_len = EXT_INIT_MAX_LEN;
1266 int has_prev, has_next;
1267 blk64_t orig_lblk;
1268 struct extent_path *path;
1269 struct ext2fs_extent extent, next_extent, prev_extent;
1270 struct ext2fs_extent newextent;
1271 struct ext2_extent_info info;
1272
1273 EXT2_CHECK_MAGIC(handle, EXT2_ET_MAGIC_EXTENT_HANDLE);
1274
1275 #ifdef DEBUG
1276 printf("set_bmap ino %u log %lld phys %lld flags %d\n",
1277 handle->ino, logical, physical, flags);
1278 #endif
1279
1280 if (!(handle->fs->flags & EXT2_FLAG_RW))
1281 return EXT2_ET_RO_FILSYS;
1282
1283 if (!handle->path)
1284 return EXT2_ET_NO_CURRENT_NODE;
1285
1286 path = handle->path + handle->level;
1287
1288 if (flags & EXT2_EXTENT_SET_BMAP_UNINIT) {
1289 new_uninit = 1;
1290 max_len = EXT_UNINIT_MAX_LEN;
1291 }
1292
1293 /* if (re)mapping, set up new extent to insert */
1294 if (physical) {
1295 newextent.e_len = 1;
1296 newextent.e_pblk = physical;
1297 newextent.e_lblk = logical;
1298 newextent.e_flags = EXT2_EXTENT_FLAGS_LEAF;
1299 if (new_uninit)
1300 newextent.e_flags |= EXT2_EXTENT_FLAGS_UNINIT;
1301 }
1302
1303 /* special case if the extent tree is completely empty */
1304 if ((handle->max_depth == 0) && (path->entries == 0)) {
1305 retval = ext2fs_extent_insert(handle, 0, &newextent);
1306 return retval;
1307 }
1308
1309 /* save our original location in the extent tree */
1310 if ((retval = ext2fs_extent_get(handle, EXT2_EXTENT_CURRENT,
1311 &extent))) {
1312 if (retval != EXT2_ET_NO_CURRENT_NODE)
1313 return retval;
1314 memset(&extent, 0, sizeof(extent));
1315 }
1316 if ((retval = ext2fs_extent_get_info(handle, &info)))
1317 return retval;
1318 orig_height = info.max_depth - info.curr_level;
1319 orig_lblk = extent.e_lblk;
1320
1321 /* go to the logical spot we want to (re/un)map */
1322 retval = ext2fs_extent_goto(handle, logical);
1323 if (retval) {
1324 if (retval == EXT2_ET_EXTENT_NOT_FOUND) {
1325 retval = 0;
1326 mapped = 0;
1327 if (!physical) {
1328 #ifdef DEBUG
1329 printf("block %llu already unmapped\n",
1330 logical);
1331 #endif
1332 goto done;
1333 }
1334 } else
1335 goto done;
1336 }
1337
1338 /*
1339 * This may be the extent *before* the requested logical,
1340 * if it's currently unmapped.
1341 *
1342 * Get the previous and next leaf extents, if they are present.
1343 */
1344 retval = ext2fs_extent_get(handle, EXT2_EXTENT_CURRENT, &extent);
1345 if (retval)
1346 goto done;
1347 if (extent.e_flags & EXT2_EXTENT_FLAGS_UNINIT)
1348 extent_uninit = 1;
1349 retval = ext2fs_extent_get(handle, EXT2_EXTENT_NEXT_LEAF, &next_extent);
1350 if (retval) {
1351 has_next = 0;
1352 if (retval != EXT2_ET_EXTENT_NO_NEXT)
1353 goto done;
1354 } else {
1355 dbg_print_extent("set_bmap: next_extent",
1356 &next_extent);
1357 has_next = 1;
1358 if (next_extent.e_flags & EXT2_EXTENT_FLAGS_UNINIT)
1359 next_uninit = 1;
1360 }
1361 retval = ext2fs_extent_goto(handle, logical);
1362 if (retval && retval != EXT2_ET_EXTENT_NOT_FOUND)
1363 goto done;
1364 retval = ext2fs_extent_get(handle, EXT2_EXTENT_PREV_LEAF, &prev_extent);
1365 if (retval) {
1366 has_prev = 0;
1367 if (retval != EXT2_ET_EXTENT_NO_PREV)
1368 goto done;
1369 } else {
1370 has_prev = 1;
1371 dbg_print_extent("set_bmap: prev_extent",
1372 &prev_extent);
1373 if (prev_extent.e_flags & EXT2_EXTENT_FLAGS_UNINIT)
1374 prev_uninit = 1;
1375 }
1376 retval = ext2fs_extent_goto(handle, logical);
1377 if (retval && retval != EXT2_ET_EXTENT_NOT_FOUND)
1378 goto done;
1379
1380 /* check if already pointing to the requested physical */
1381 if (mapped && (new_uninit == extent_uninit) &&
1382 (extent.e_pblk + (logical - extent.e_lblk) == physical)) {
1383 #ifdef DEBUG
1384 printf("physical block (at %llu) unchanged\n", logical);
1385 #endif
1386 goto done;
1387 }
1388
1389 if (!mapped) {
1390 #ifdef DEBUG
1391 printf("mapping unmapped logical block %llu\n", logical);
1392 #endif
1393 if ((logical == extent.e_lblk + extent.e_len) &&
1394 (physical == extent.e_pblk + extent.e_len) &&
1395 (new_uninit == extent_uninit) &&
1396 ((int) extent.e_len < max_len-1)) {
1397 extent.e_len++;
1398 retval = ext2fs_extent_replace(handle, 0, &extent);
1399 } else if ((logical == extent.e_lblk - 1) &&
1400 (physical == extent.e_pblk - 1) &&
1401 (new_uninit == extent_uninit) &&
1402 ((int) extent.e_len < max_len - 1)) {
1403 extent.e_len++;
1404 extent.e_lblk--;
1405 extent.e_pblk--;
1406 retval = ext2fs_extent_replace(handle, 0, &extent);
1407 } else if (has_next &&
1408 (logical == next_extent.e_lblk - 1) &&
1409 (physical == next_extent.e_pblk - 1) &&
1410 (new_uninit == next_uninit) &&
1411 ((int) next_extent.e_len < max_len - 1)) {
1412 retval = ext2fs_extent_get(handle,
1413 EXT2_EXTENT_NEXT_LEAF,
1414 &next_extent);
1415 if (retval)
1416 goto done;
1417 next_extent.e_len++;
1418 next_extent.e_lblk--;
1419 next_extent.e_pblk--;
1420 retval = ext2fs_extent_replace(handle, 0, &next_extent);
1421 } else if (logical < extent.e_lblk)
1422 retval = ext2fs_extent_insert(handle, 0, &newextent);
1423 else
1424 retval = ext2fs_extent_insert(handle,
1425 EXT2_EXTENT_INSERT_AFTER, &newextent);
1426 if (retval)
1427 goto done;
1428 retval = ext2fs_extent_fix_parents(handle);
1429 if (retval)
1430 goto done;
1431 } else if ((logical == extent.e_lblk) && (extent.e_len == 1)) {
1432 #ifdef DEBUG
1433 printf("(re/un)mapping only block in extent\n");
1434 #endif
1435 if (physical) {
1436 retval = ext2fs_extent_replace(handle, 0, &newextent);
1437 } else {
1438 retval = ext2fs_extent_delete(handle, 0);
1439 if (retval)
1440 goto done;
1441 ec = ext2fs_extent_fix_parents(handle);
1442 if (ec != EXT2_ET_NO_CURRENT_NODE)
1443 retval = ec;
1444 }
1445
1446 if (retval)
1447 goto done;
1448 } else if (logical == extent.e_lblk + extent.e_len - 1) {
1449 #ifdef DEBUG
1450 printf("(re/un)mapping last block in extent\n");
1451 #endif
1452 if (physical) {
1453 if (has_next &&
1454 (logical == (next_extent.e_lblk - 1)) &&
1455 (physical == (next_extent.e_pblk - 1)) &&
1456 (new_uninit == next_uninit) &&
1457 ((int) next_extent.e_len < max_len - 1)) {
1458 retval = ext2fs_extent_get(handle,
1459 EXT2_EXTENT_NEXT_LEAF, &next_extent);
1460 if (retval)
1461 goto done;
1462 next_extent.e_len++;
1463 next_extent.e_lblk--;
1464 next_extent.e_pblk--;
1465 retval = ext2fs_extent_replace(handle, 0,
1466 &next_extent);
1467 if (retval)
1468 goto done;
1469 } else
1470 retval = ext2fs_extent_insert(handle,
1471 EXT2_EXTENT_INSERT_AFTER, &newextent);
1472 if (retval)
1473 goto done;
1474 retval = ext2fs_extent_fix_parents(handle);
1475 if (retval)
1476 goto done;
1477 /*
1478 * Now pointing at inserted extent; move back to prev.
1479 *
1480 * We cannot use EXT2_EXTENT_PREV to go back; note the
1481 * subtlety in the comment for fix_parents().
1482 */
1483 retval = ext2fs_extent_goto(handle, logical);
1484 if (retval)
1485 goto done;
1486 retval = ext2fs_extent_get(handle,
1487 EXT2_EXTENT_CURRENT,
1488 &extent);
1489 if (retval)
1490 goto done;
1491 }
1492 extent.e_len--;
1493 retval = ext2fs_extent_replace(handle, 0, &extent);
1494 if (retval)
1495 goto done;
1496 } else if (logical == extent.e_lblk) {
1497 #ifdef DEBUG
1498 printf("(re/un)mapping first block in extent\n");
1499 #endif
1500 if (physical) {
1501 if (has_prev &&
1502 (logical == (prev_extent.e_lblk +
1503 prev_extent.e_len)) &&
1504 (physical == (prev_extent.e_pblk +
1505 prev_extent.e_len)) &&
1506 (new_uninit == prev_uninit) &&
1507 ((int) prev_extent.e_len < max_len-1)) {
1508 retval = ext2fs_extent_get(handle,
1509 EXT2_EXTENT_PREV_LEAF, &prev_extent);
1510 if (retval)
1511 goto done;
1512 prev_extent.e_len++;
1513 retval = ext2fs_extent_replace(handle, 0,
1514 &prev_extent);
1515 } else
1516 retval = ext2fs_extent_insert(handle,
1517 0, &newextent);
1518 if (retval)
1519 goto done;
1520 retval = ext2fs_extent_fix_parents(handle);
1521 if (retval)
1522 goto done;
1523 retval = ext2fs_extent_get(handle,
1524 EXT2_EXTENT_NEXT_LEAF,
1525 &extent);
1526 if (retval)
1527 goto done;
1528 }
1529 extent.e_pblk++;
1530 extent.e_lblk++;
1531 extent.e_len--;
1532 retval = ext2fs_extent_replace(handle, 0, &extent);
1533 if (retval)
1534 goto done;
1535 retval = ext2fs_extent_fix_parents(handle);
1536 if (retval)
1537 goto done;
1538 } else {
1539 __u32 save_length;
1540 blk64_t save_lblk;
1541 struct ext2fs_extent save_extent;
1542 errcode_t r2;
1543
1544 #ifdef DEBUG
1545 printf("(re/un)mapping in middle of extent\n");
1546 #endif
1547 /* need to split this extent; later */
1548 save_lblk = extent.e_lblk;
1549 save_length = extent.e_len;
1550 save_extent = extent;
1551
1552 /* shorten pre-split extent */
1553 extent.e_len = (logical - extent.e_lblk);
1554 retval = ext2fs_extent_replace(handle, 0, &extent);
1555 if (retval)
1556 goto done;
1557 /* insert our new extent, if any */
1558 if (physical) {
1559 /* insert new extent after current */
1560 retval = ext2fs_extent_insert(handle,
1561 EXT2_EXTENT_INSERT_AFTER, &newextent);
1562 if (retval) {
1563 r2 = ext2fs_extent_goto(handle, save_lblk);
1564 if (r2 == 0)
1565 (void)ext2fs_extent_replace(handle, 0,
1566 &save_extent);
1567 goto done;
1568 }
1569 }
1570 /* add post-split extent */
1571 extent.e_pblk += extent.e_len + 1;
1572 extent.e_lblk += extent.e_len + 1;
1573 extent.e_len = save_length - extent.e_len - 1;
1574 retval = ext2fs_extent_insert(handle,
1575 EXT2_EXTENT_INSERT_AFTER, &extent);
1576 if (retval) {
1577 if (physical) {
1578 r2 = ext2fs_extent_goto(handle,
1579 newextent.e_lblk);
1580 if (r2 == 0)
1581 (void)ext2fs_extent_delete(handle, 0);
1582 }
1583 r2 = ext2fs_extent_goto(handle, save_lblk);
1584 if (r2 == 0)
1585 (void)ext2fs_extent_replace(handle, 0,
1586 &save_extent);
1587 goto done;
1588 }
1589 }
1590
1591 done:
1592 /* get handle back to its position */
1593 if (orig_height > handle->max_depth)
1594 orig_height = handle->max_depth; /* In case we shortened the tree */
1595 ext2fs_extent_goto2(handle, orig_height, orig_lblk);
1596 return retval;
1597 }
1598
ext2fs_extent_delete(ext2_extent_handle_t handle,int flags)1599 errcode_t ext2fs_extent_delete(ext2_extent_handle_t handle, int flags)
1600 {
1601 struct extent_path *path;
1602 char *cp;
1603 struct ext3_extent_header *eh;
1604 errcode_t retval = 0;
1605
1606 EXT2_CHECK_MAGIC(handle, EXT2_ET_MAGIC_EXTENT_HANDLE);
1607
1608 if (!(handle->fs->flags & EXT2_FLAG_RW))
1609 return EXT2_ET_RO_FILSYS;
1610
1611 if (!handle->path)
1612 return EXT2_ET_NO_CURRENT_NODE;
1613
1614 #ifdef DEBUG
1615 {
1616 struct ext2fs_extent extent;
1617
1618 retval = ext2fs_extent_get(handle, EXT2_EXTENT_CURRENT,
1619 &extent);
1620 if (retval == 0) {
1621 printf("extent delete %u ", handle->ino);
1622 dbg_print_extent(0, &extent);
1623 }
1624 }
1625 #endif
1626
1627 path = handle->path + handle->level;
1628 if (!path->curr)
1629 return EXT2_ET_NO_CURRENT_NODE;
1630
1631 cp = path->curr;
1632
1633 if (path->left) {
1634 memmove(cp, cp + sizeof(struct ext3_extent_idx),
1635 path->left * sizeof(struct ext3_extent_idx));
1636 path->left--;
1637 } else {
1638 struct ext3_extent_idx *ix = path->curr;
1639 ix--;
1640 path->curr = ix;
1641 }
1642 if (--path->entries == 0)
1643 path->curr = 0;
1644
1645 /* if non-root node has no entries left, remove it & parent ptr to it */
1646 if (path->entries == 0 && handle->level) {
1647 if (!(flags & EXT2_EXTENT_DELETE_KEEP_EMPTY)) {
1648 struct ext2fs_extent extent;
1649
1650 retval = ext2fs_extent_get(handle, EXT2_EXTENT_UP,
1651 &extent);
1652 if (retval)
1653 return retval;
1654
1655 retval = ext2fs_extent_delete(handle, flags);
1656 handle->inode->i_blocks -=
1657 (handle->fs->blocksize *
1658 EXT2FS_CLUSTER_RATIO(handle->fs)) / 512;
1659 retval = ext2fs_write_inode(handle->fs, handle->ino,
1660 handle->inode);
1661 ext2fs_block_alloc_stats2(handle->fs,
1662 extent.e_pblk, -1);
1663 }
1664 } else {
1665 eh = (struct ext3_extent_header *) path->buf;
1666 eh->eh_entries = ext2fs_cpu_to_le16(path->entries);
1667 if ((path->entries == 0) && (handle->level == 0)) {
1668 eh->eh_depth = 0;
1669 handle->max_depth = 0;
1670 }
1671 retval = update_path(handle);
1672 }
1673 return retval;
1674 }
1675
ext2fs_extent_get_info(ext2_extent_handle_t handle,struct ext2_extent_info * info)1676 errcode_t ext2fs_extent_get_info(ext2_extent_handle_t handle,
1677 struct ext2_extent_info *info)
1678 {
1679 struct extent_path *path;
1680
1681 EXT2_CHECK_MAGIC(handle, EXT2_ET_MAGIC_EXTENT_HANDLE);
1682
1683 memset(info, 0, sizeof(struct ext2_extent_info));
1684
1685 path = handle->path + handle->level;
1686 if (path) {
1687 if (path->curr)
1688 info->curr_entry = ((char *) path->curr - path->buf) /
1689 sizeof(struct ext3_extent_idx);
1690 else
1691 info->curr_entry = 0;
1692 info->num_entries = path->entries;
1693 info->max_entries = path->max_entries;
1694 info->bytes_avail = (path->max_entries - path->entries) *
1695 sizeof(struct ext3_extent);
1696 }
1697
1698 info->curr_level = handle->level;
1699 info->max_depth = handle->max_depth;
1700 info->max_lblk = EXT_MAX_EXTENT_LBLK;
1701 info->max_pblk = EXT_MAX_EXTENT_PBLK;
1702 info->max_len = EXT_INIT_MAX_LEN;
1703 info->max_uninit_len = EXT_UNINIT_MAX_LEN;
1704
1705 return 0;
1706 }
1707
ul_log2(unsigned long arg)1708 static int ul_log2(unsigned long arg)
1709 {
1710 int l = 0;
1711
1712 arg >>= 1;
1713 while (arg) {
1714 l++;
1715 arg >>= 1;
1716 }
1717 return l;
1718 }
1719
ext2fs_max_extent_depth(ext2_extent_handle_t handle)1720 size_t ext2fs_max_extent_depth(ext2_extent_handle_t handle)
1721 {
1722 size_t iblock_sz = sizeof(((struct ext2_inode *)NULL)->i_block);
1723 size_t iblock_extents = (iblock_sz - sizeof(struct ext3_extent_header)) /
1724 sizeof(struct ext3_extent);
1725 size_t extents_per_block = (handle->fs->blocksize -
1726 sizeof(struct ext3_extent_header)) /
1727 sizeof(struct ext3_extent);
1728 static unsigned int last_blocksize = 0;
1729 static size_t last_result = 0;
1730
1731 if (last_blocksize && last_blocksize == handle->fs->blocksize)
1732 return last_result;
1733
1734 last_result = 1 + ((ul_log2(EXT_MAX_EXTENT_LBLK) - ul_log2(iblock_extents)) /
1735 ul_log2(extents_per_block));
1736 last_blocksize = handle->fs->blocksize;
1737 return last_result;
1738 }
1739
1740 #ifdef DEBUG
1741 /*
1742 * Override debugfs's prompt
1743 */
1744 const char *debug_prog_name = "tst_extents";
1745
1746 #endif
1747
1748