1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Copyright (C) 2017-2018 HUAWEI, Inc.
4 * https://www.huawei.com/
5 */
6 #include <linux/module.h>
7 #include <linux/buffer_head.h>
8 #include <linux/statfs.h>
9 #include <linux/parser.h>
10 #include <linux/seq_file.h>
11 #include <linux/crc32c.h>
12 #include <linux/fs_context.h>
13 #include <linux/fs_parser.h>
14 #include <linux/dax.h>
15 #include "xattr.h"
16
17 #define CREATE_TRACE_POINTS
18 #include <trace/events/erofs.h>
19
20 static struct kmem_cache *erofs_inode_cachep __read_mostly;
21
_erofs_err(struct super_block * sb,const char * function,const char * fmt,...)22 void _erofs_err(struct super_block *sb, const char *function,
23 const char *fmt, ...)
24 {
25 struct va_format vaf;
26 va_list args;
27
28 va_start(args, fmt);
29
30 vaf.fmt = fmt;
31 vaf.va = &args;
32
33 pr_err("(device %s): %s: %pV", sb->s_id, function, &vaf);
34 va_end(args);
35 }
36
_erofs_info(struct super_block * sb,const char * function,const char * fmt,...)37 void _erofs_info(struct super_block *sb, const char *function,
38 const char *fmt, ...)
39 {
40 struct va_format vaf;
41 va_list args;
42
43 va_start(args, fmt);
44
45 vaf.fmt = fmt;
46 vaf.va = &args;
47
48 pr_info("(device %s): %pV", sb->s_id, &vaf);
49 va_end(args);
50 }
51
erofs_superblock_csum_verify(struct super_block * sb,void * sbdata)52 static int erofs_superblock_csum_verify(struct super_block *sb, void *sbdata)
53 {
54 struct erofs_super_block *dsb;
55 u32 expected_crc, crc;
56
57 dsb = kmemdup(sbdata + EROFS_SUPER_OFFSET,
58 EROFS_BLKSIZ - EROFS_SUPER_OFFSET, GFP_KERNEL);
59 if (!dsb)
60 return -ENOMEM;
61
62 expected_crc = le32_to_cpu(dsb->checksum);
63 dsb->checksum = 0;
64 /* to allow for x86 boot sectors and other oddities. */
65 crc = crc32c(~0, dsb, EROFS_BLKSIZ - EROFS_SUPER_OFFSET);
66 kfree(dsb);
67
68 if (crc != expected_crc) {
69 erofs_err(sb, "invalid checksum 0x%08x, 0x%08x expected",
70 crc, expected_crc);
71 return -EBADMSG;
72 }
73 return 0;
74 }
75
erofs_inode_init_once(void * ptr)76 static void erofs_inode_init_once(void *ptr)
77 {
78 struct erofs_inode *vi = ptr;
79
80 inode_init_once(&vi->vfs_inode);
81 }
82
erofs_alloc_inode(struct super_block * sb)83 static struct inode *erofs_alloc_inode(struct super_block *sb)
84 {
85 struct erofs_inode *vi =
86 kmem_cache_alloc(erofs_inode_cachep, GFP_KERNEL);
87
88 if (!vi)
89 return NULL;
90
91 /* zero out everything except vfs_inode */
92 memset(vi, 0, offsetof(struct erofs_inode, vfs_inode));
93 return &vi->vfs_inode;
94 }
95
erofs_free_inode(struct inode * inode)96 static void erofs_free_inode(struct inode *inode)
97 {
98 struct erofs_inode *vi = EROFS_I(inode);
99
100 /* be careful of RCU symlink path */
101 if (inode->i_op == &erofs_fast_symlink_iops)
102 kfree(inode->i_link);
103 kfree(vi->xattr_shared_xattrs);
104
105 kmem_cache_free(erofs_inode_cachep, vi);
106 }
107
check_layout_compatibility(struct super_block * sb,struct erofs_super_block * dsb)108 static bool check_layout_compatibility(struct super_block *sb,
109 struct erofs_super_block *dsb)
110 {
111 const unsigned int feature = le32_to_cpu(dsb->feature_incompat);
112
113 EROFS_SB(sb)->feature_incompat = feature;
114
115 /* check if current kernel meets all mandatory requirements */
116 if (feature & (~EROFS_ALL_FEATURE_INCOMPAT)) {
117 erofs_err(sb,
118 "unidentified incompatible feature %x, please upgrade kernel version",
119 feature & ~EROFS_ALL_FEATURE_INCOMPAT);
120 return false;
121 }
122 return true;
123 }
124
125 #ifdef CONFIG_EROFS_FS_ZIP
126 /* read variable-sized metadata, offset will be aligned by 4-byte */
erofs_read_metadata(struct super_block * sb,struct page ** pagep,erofs_off_t * offset,int * lengthp)127 static void *erofs_read_metadata(struct super_block *sb, struct page **pagep,
128 erofs_off_t *offset, int *lengthp)
129 {
130 struct page *page = *pagep;
131 u8 *buffer, *ptr;
132 int len, i, cnt;
133 erofs_blk_t blk;
134
135 *offset = round_up(*offset, 4);
136 blk = erofs_blknr(*offset);
137
138 if (!page || page->index != blk) {
139 if (page) {
140 unlock_page(page);
141 put_page(page);
142 }
143 page = erofs_get_meta_page(sb, blk);
144 if (IS_ERR(page))
145 goto err_nullpage;
146 }
147
148 ptr = kmap(page);
149 len = le16_to_cpu(*(__le16 *)&ptr[erofs_blkoff(*offset)]);
150 if (!len)
151 len = U16_MAX + 1;
152 buffer = kmalloc(len, GFP_KERNEL);
153 if (!buffer) {
154 buffer = ERR_PTR(-ENOMEM);
155 goto out;
156 }
157 *offset += sizeof(__le16);
158 *lengthp = len;
159
160 for (i = 0; i < len; i += cnt) {
161 cnt = min(EROFS_BLKSIZ - (int)erofs_blkoff(*offset), len - i);
162 blk = erofs_blknr(*offset);
163
164 if (!page || page->index != blk) {
165 if (page) {
166 kunmap(page);
167 unlock_page(page);
168 put_page(page);
169 }
170 page = erofs_get_meta_page(sb, blk);
171 if (IS_ERR(page)) {
172 kfree(buffer);
173 goto err_nullpage;
174 }
175 ptr = kmap(page);
176 }
177 memcpy(buffer + i, ptr + erofs_blkoff(*offset), cnt);
178 *offset += cnt;
179 }
180 out:
181 kunmap(page);
182 *pagep = page;
183 return buffer;
184 err_nullpage:
185 *pagep = NULL;
186 return page;
187 }
188
erofs_load_compr_cfgs(struct super_block * sb,struct erofs_super_block * dsb)189 static int erofs_load_compr_cfgs(struct super_block *sb,
190 struct erofs_super_block *dsb)
191 {
192 struct erofs_sb_info *sbi;
193 struct page *page;
194 unsigned int algs, alg;
195 erofs_off_t offset;
196 int size, ret;
197
198 sbi = EROFS_SB(sb);
199 sbi->available_compr_algs = le16_to_cpu(dsb->u1.available_compr_algs);
200
201 if (sbi->available_compr_algs & ~Z_EROFS_ALL_COMPR_ALGS) {
202 erofs_err(sb, "try to load compressed fs with unsupported algorithms %x",
203 sbi->available_compr_algs & ~Z_EROFS_ALL_COMPR_ALGS);
204 return -EINVAL;
205 }
206
207 offset = EROFS_SUPER_OFFSET + sbi->sb_size;
208 page = NULL;
209 alg = 0;
210 ret = 0;
211
212 for (algs = sbi->available_compr_algs; algs; algs >>= 1, ++alg) {
213 void *data;
214
215 if (!(algs & 1))
216 continue;
217
218 data = erofs_read_metadata(sb, &page, &offset, &size);
219 if (IS_ERR(data)) {
220 ret = PTR_ERR(data);
221 goto err;
222 }
223
224 switch (alg) {
225 case Z_EROFS_COMPRESSION_LZ4:
226 ret = z_erofs_load_lz4_config(sb, dsb, data, size);
227 break;
228 case Z_EROFS_COMPRESSION_LZMA:
229 ret = z_erofs_load_lzma_config(sb, dsb, data, size);
230 break;
231 default:
232 DBG_BUGON(1);
233 ret = -EFAULT;
234 }
235 kfree(data);
236 if (ret)
237 goto err;
238 }
239 err:
240 if (page) {
241 unlock_page(page);
242 put_page(page);
243 }
244 return ret;
245 }
246 #else
erofs_load_compr_cfgs(struct super_block * sb,struct erofs_super_block * dsb)247 static int erofs_load_compr_cfgs(struct super_block *sb,
248 struct erofs_super_block *dsb)
249 {
250 if (dsb->u1.available_compr_algs) {
251 erofs_err(sb, "try to load compressed fs when compression is disabled");
252 return -EINVAL;
253 }
254 return 0;
255 }
256 #endif
257
erofs_init_devices(struct super_block * sb,struct erofs_super_block * dsb)258 static int erofs_init_devices(struct super_block *sb,
259 struct erofs_super_block *dsb)
260 {
261 struct erofs_sb_info *sbi = EROFS_SB(sb);
262 unsigned int ondisk_extradevs;
263 erofs_off_t pos;
264 struct page *page = NULL;
265 struct erofs_device_info *dif;
266 struct erofs_deviceslot *dis;
267 void *ptr;
268 int id, err = 0;
269
270 sbi->total_blocks = sbi->primarydevice_blocks;
271 if (!erofs_sb_has_device_table(sbi))
272 ondisk_extradevs = 0;
273 else
274 ondisk_extradevs = le16_to_cpu(dsb->extra_devices);
275
276 if (ondisk_extradevs != sbi->devs->extra_devices) {
277 erofs_err(sb, "extra devices don't match (ondisk %u, given %u)",
278 ondisk_extradevs, sbi->devs->extra_devices);
279 return -EINVAL;
280 }
281 if (!ondisk_extradevs)
282 return 0;
283
284 sbi->device_id_mask = roundup_pow_of_two(ondisk_extradevs + 1) - 1;
285 pos = le16_to_cpu(dsb->devt_slotoff) * EROFS_DEVT_SLOT_SIZE;
286 down_read(&sbi->devs->rwsem);
287 idr_for_each_entry(&sbi->devs->tree, dif, id) {
288 erofs_blk_t blk = erofs_blknr(pos);
289 struct block_device *bdev;
290
291 if (!page || page->index != blk) {
292 if (page) {
293 kunmap(page);
294 unlock_page(page);
295 put_page(page);
296 }
297
298 page = erofs_get_meta_page(sb, blk);
299 if (IS_ERR(page)) {
300 up_read(&sbi->devs->rwsem);
301 return PTR_ERR(page);
302 }
303 ptr = kmap(page);
304 }
305 dis = ptr + erofs_blkoff(pos);
306
307 bdev = blkdev_get_by_path(dif->path,
308 FMODE_READ | FMODE_EXCL,
309 sb->s_type);
310 if (IS_ERR(bdev)) {
311 err = PTR_ERR(bdev);
312 goto err_out;
313 }
314 dif->bdev = bdev;
315 dif->dax_dev = fs_dax_get_by_bdev(bdev);
316 dif->blocks = le32_to_cpu(dis->blocks);
317 dif->mapped_blkaddr = le32_to_cpu(dis->mapped_blkaddr);
318 sbi->total_blocks += dif->blocks;
319 pos += EROFS_DEVT_SLOT_SIZE;
320 }
321 err_out:
322 up_read(&sbi->devs->rwsem);
323 if (page) {
324 kunmap(page);
325 unlock_page(page);
326 put_page(page);
327 }
328 return err;
329 }
330
erofs_read_superblock(struct super_block * sb)331 static int erofs_read_superblock(struct super_block *sb)
332 {
333 struct erofs_sb_info *sbi;
334 struct page *page;
335 struct erofs_super_block *dsb;
336 unsigned int blkszbits;
337 void *data;
338 int ret;
339
340 page = read_mapping_page(sb->s_bdev->bd_inode->i_mapping, 0, NULL);
341 if (IS_ERR(page)) {
342 erofs_err(sb, "cannot read erofs superblock");
343 return PTR_ERR(page);
344 }
345
346 sbi = EROFS_SB(sb);
347
348 data = kmap(page);
349 dsb = (struct erofs_super_block *)(data + EROFS_SUPER_OFFSET);
350
351 ret = -EINVAL;
352 if (le32_to_cpu(dsb->magic) != EROFS_SUPER_MAGIC_V1) {
353 erofs_err(sb, "cannot find valid erofs superblock");
354 goto out;
355 }
356
357 sbi->feature_compat = le32_to_cpu(dsb->feature_compat);
358 if (erofs_sb_has_sb_chksum(sbi)) {
359 ret = erofs_superblock_csum_verify(sb, data);
360 if (ret)
361 goto out;
362 }
363
364 ret = -EINVAL;
365 blkszbits = dsb->blkszbits;
366 /* 9(512 bytes) + LOG_SECTORS_PER_BLOCK == LOG_BLOCK_SIZE */
367 if (blkszbits != LOG_BLOCK_SIZE) {
368 erofs_err(sb, "blkszbits %u isn't supported on this platform",
369 blkszbits);
370 goto out;
371 }
372
373 if (!check_layout_compatibility(sb, dsb))
374 goto out;
375
376 sbi->sb_size = 128 + dsb->sb_extslots * EROFS_SB_EXTSLOT_SIZE;
377 if (sbi->sb_size > EROFS_BLKSIZ) {
378 erofs_err(sb, "invalid sb_extslots %u (more than a fs block)",
379 sbi->sb_size);
380 goto out;
381 }
382 sbi->primarydevice_blocks = le32_to_cpu(dsb->blocks);
383 sbi->meta_blkaddr = le32_to_cpu(dsb->meta_blkaddr);
384 #ifdef CONFIG_EROFS_FS_XATTR
385 sbi->xattr_blkaddr = le32_to_cpu(dsb->xattr_blkaddr);
386 #endif
387 sbi->islotbits = ilog2(sizeof(struct erofs_inode_compact));
388 sbi->root_nid = le16_to_cpu(dsb->root_nid);
389 sbi->inos = le64_to_cpu(dsb->inos);
390
391 sbi->build_time = le64_to_cpu(dsb->build_time);
392 sbi->build_time_nsec = le32_to_cpu(dsb->build_time_nsec);
393
394 memcpy(&sb->s_uuid, dsb->uuid, sizeof(dsb->uuid));
395
396 ret = strscpy(sbi->volume_name, dsb->volume_name,
397 sizeof(dsb->volume_name));
398 if (ret < 0) { /* -E2BIG */
399 erofs_err(sb, "bad volume name without NIL terminator");
400 ret = -EFSCORRUPTED;
401 goto out;
402 }
403
404 /* parse on-disk compression configurations */
405 if (erofs_sb_has_compr_cfgs(sbi))
406 ret = erofs_load_compr_cfgs(sb, dsb);
407 else
408 ret = z_erofs_load_lz4_config(sb, dsb, NULL, 0);
409 if (ret < 0)
410 goto out;
411
412 /* handle multiple devices */
413 ret = erofs_init_devices(sb, dsb);
414 out:
415 kunmap(page);
416 put_page(page);
417 return ret;
418 }
419
420 /* set up default EROFS parameters */
erofs_default_options(struct erofs_fs_context * ctx)421 static void erofs_default_options(struct erofs_fs_context *ctx)
422 {
423 #ifdef CONFIG_EROFS_FS_ZIP
424 ctx->opt.cache_strategy = EROFS_ZIP_CACHE_READAROUND;
425 ctx->opt.max_sync_decompress_pages = 3;
426 ctx->opt.readahead_sync_decompress = false;
427 #endif
428 #ifdef CONFIG_EROFS_FS_XATTR
429 set_opt(&ctx->opt, XATTR_USER);
430 #endif
431 #ifdef CONFIG_EROFS_FS_POSIX_ACL
432 set_opt(&ctx->opt, POSIX_ACL);
433 #endif
434 }
435
436 enum {
437 Opt_user_xattr,
438 Opt_acl,
439 Opt_cache_strategy,
440 Opt_dax,
441 Opt_dax_enum,
442 Opt_device,
443 Opt_err
444 };
445
446 static const struct constant_table erofs_param_cache_strategy[] = {
447 {"disabled", EROFS_ZIP_CACHE_DISABLED},
448 {"readahead", EROFS_ZIP_CACHE_READAHEAD},
449 {"readaround", EROFS_ZIP_CACHE_READAROUND},
450 {}
451 };
452
453 static const struct constant_table erofs_dax_param_enums[] = {
454 {"always", EROFS_MOUNT_DAX_ALWAYS},
455 {"never", EROFS_MOUNT_DAX_NEVER},
456 {}
457 };
458
459 static const struct fs_parameter_spec erofs_fs_parameters[] = {
460 fsparam_flag_no("user_xattr", Opt_user_xattr),
461 fsparam_flag_no("acl", Opt_acl),
462 fsparam_enum("cache_strategy", Opt_cache_strategy,
463 erofs_param_cache_strategy),
464 fsparam_flag("dax", Opt_dax),
465 fsparam_enum("dax", Opt_dax_enum, erofs_dax_param_enums),
466 fsparam_string("device", Opt_device),
467 {}
468 };
469
erofs_fc_set_dax_mode(struct fs_context * fc,unsigned int mode)470 static bool erofs_fc_set_dax_mode(struct fs_context *fc, unsigned int mode)
471 {
472 #ifdef CONFIG_FS_DAX
473 struct erofs_fs_context *ctx = fc->fs_private;
474
475 switch (mode) {
476 case EROFS_MOUNT_DAX_ALWAYS:
477 warnfc(fc, "DAX enabled. Warning: EXPERIMENTAL, use at your own risk");
478 set_opt(&ctx->opt, DAX_ALWAYS);
479 clear_opt(&ctx->opt, DAX_NEVER);
480 return true;
481 case EROFS_MOUNT_DAX_NEVER:
482 set_opt(&ctx->opt, DAX_NEVER);
483 clear_opt(&ctx->opt, DAX_ALWAYS);
484 return true;
485 default:
486 DBG_BUGON(1);
487 return false;
488 }
489 #else
490 errorfc(fc, "dax options not supported");
491 return false;
492 #endif
493 }
494
erofs_fc_parse_param(struct fs_context * fc,struct fs_parameter * param)495 static int erofs_fc_parse_param(struct fs_context *fc,
496 struct fs_parameter *param)
497 {
498 struct erofs_fs_context *ctx = fc->fs_private;
499 struct fs_parse_result result;
500 struct erofs_device_info *dif;
501 int opt, ret;
502
503 opt = fs_parse(fc, erofs_fs_parameters, param, &result);
504 if (opt < 0)
505 return opt;
506
507 switch (opt) {
508 case Opt_user_xattr:
509 #ifdef CONFIG_EROFS_FS_XATTR
510 if (result.boolean)
511 set_opt(&ctx->opt, XATTR_USER);
512 else
513 clear_opt(&ctx->opt, XATTR_USER);
514 #else
515 errorfc(fc, "{,no}user_xattr options not supported");
516 #endif
517 break;
518 case Opt_acl:
519 #ifdef CONFIG_EROFS_FS_POSIX_ACL
520 if (result.boolean)
521 set_opt(&ctx->opt, POSIX_ACL);
522 else
523 clear_opt(&ctx->opt, POSIX_ACL);
524 #else
525 errorfc(fc, "{,no}acl options not supported");
526 #endif
527 break;
528 case Opt_cache_strategy:
529 #ifdef CONFIG_EROFS_FS_ZIP
530 ctx->opt.cache_strategy = result.uint_32;
531 #else
532 errorfc(fc, "compression not supported, cache_strategy ignored");
533 #endif
534 break;
535 case Opt_dax:
536 if (!erofs_fc_set_dax_mode(fc, EROFS_MOUNT_DAX_ALWAYS))
537 return -EINVAL;
538 break;
539 case Opt_dax_enum:
540 if (!erofs_fc_set_dax_mode(fc, result.uint_32))
541 return -EINVAL;
542 break;
543 case Opt_device:
544 dif = kzalloc(sizeof(*dif), GFP_KERNEL);
545 if (!dif)
546 return -ENOMEM;
547 dif->path = kstrdup(param->string, GFP_KERNEL);
548 if (!dif->path) {
549 kfree(dif);
550 return -ENOMEM;
551 }
552 down_write(&ctx->devs->rwsem);
553 ret = idr_alloc(&ctx->devs->tree, dif, 0, 0, GFP_KERNEL);
554 up_write(&ctx->devs->rwsem);
555 if (ret < 0) {
556 kfree(dif->path);
557 kfree(dif);
558 return ret;
559 }
560 ++ctx->devs->extra_devices;
561 break;
562 default:
563 return -ENOPARAM;
564 }
565 return 0;
566 }
567
568 #ifdef CONFIG_EROFS_FS_ZIP
569 static const struct address_space_operations managed_cache_aops;
570
erofs_managed_cache_releasepage(struct page * page,gfp_t gfp_mask)571 static int erofs_managed_cache_releasepage(struct page *page, gfp_t gfp_mask)
572 {
573 int ret = 1; /* 0 - busy */
574 struct address_space *const mapping = page->mapping;
575
576 DBG_BUGON(!PageLocked(page));
577 DBG_BUGON(mapping->a_ops != &managed_cache_aops);
578
579 if (PagePrivate(page))
580 ret = erofs_try_to_free_cached_page(page);
581
582 return ret;
583 }
584
erofs_managed_cache_invalidatepage(struct page * page,unsigned int offset,unsigned int length)585 static void erofs_managed_cache_invalidatepage(struct page *page,
586 unsigned int offset,
587 unsigned int length)
588 {
589 const unsigned int stop = length + offset;
590
591 DBG_BUGON(!PageLocked(page));
592
593 /* Check for potential overflow in debug mode */
594 DBG_BUGON(stop > PAGE_SIZE || stop < length);
595
596 if (offset == 0 && stop == PAGE_SIZE)
597 while (!erofs_managed_cache_releasepage(page, GFP_NOFS))
598 cond_resched();
599 }
600
601 static const struct address_space_operations managed_cache_aops = {
602 .releasepage = erofs_managed_cache_releasepage,
603 .invalidatepage = erofs_managed_cache_invalidatepage,
604 };
605
erofs_init_managed_cache(struct super_block * sb)606 static int erofs_init_managed_cache(struct super_block *sb)
607 {
608 struct erofs_sb_info *const sbi = EROFS_SB(sb);
609 struct inode *const inode = new_inode(sb);
610
611 if (!inode)
612 return -ENOMEM;
613
614 set_nlink(inode, 1);
615 inode->i_size = OFFSET_MAX;
616
617 inode->i_mapping->a_ops = &managed_cache_aops;
618 mapping_set_gfp_mask(inode->i_mapping,
619 GFP_NOFS | __GFP_HIGHMEM | __GFP_MOVABLE);
620 sbi->managed_cache = inode;
621 return 0;
622 }
623 #else
erofs_init_managed_cache(struct super_block * sb)624 static int erofs_init_managed_cache(struct super_block *sb) { return 0; }
625 #endif
626
erofs_fc_fill_super(struct super_block * sb,struct fs_context * fc)627 static int erofs_fc_fill_super(struct super_block *sb, struct fs_context *fc)
628 {
629 struct inode *inode;
630 struct erofs_sb_info *sbi;
631 struct erofs_fs_context *ctx = fc->fs_private;
632 int err;
633
634 sb->s_magic = EROFS_SUPER_MAGIC;
635
636 if (!sb_set_blocksize(sb, EROFS_BLKSIZ)) {
637 erofs_err(sb, "failed to set erofs blksize");
638 return -EINVAL;
639 }
640
641 sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
642 if (!sbi)
643 return -ENOMEM;
644
645 sb->s_fs_info = sbi;
646 sbi->opt = ctx->opt;
647 sbi->dax_dev = fs_dax_get_by_bdev(sb->s_bdev);
648 sbi->devs = ctx->devs;
649 ctx->devs = NULL;
650
651 err = erofs_read_superblock(sb);
652 if (err)
653 return err;
654
655 if (test_opt(&sbi->opt, DAX_ALWAYS) &&
656 !dax_supported(sbi->dax_dev, sb->s_bdev, EROFS_BLKSIZ, 0, bdev_nr_sectors(sb->s_bdev))) {
657 errorfc(fc, "DAX unsupported by block device. Turning off DAX.");
658 clear_opt(&sbi->opt, DAX_ALWAYS);
659 }
660 sb->s_flags |= SB_RDONLY | SB_NOATIME;
661 sb->s_maxbytes = MAX_LFS_FILESIZE;
662 sb->s_time_gran = 1;
663
664 sb->s_op = &erofs_sops;
665 sb->s_xattr = erofs_xattr_handlers;
666
667 if (test_opt(&sbi->opt, POSIX_ACL))
668 sb->s_flags |= SB_POSIXACL;
669 else
670 sb->s_flags &= ~SB_POSIXACL;
671
672 #ifdef CONFIG_EROFS_FS_ZIP
673 xa_init(&sbi->managed_pslots);
674 #endif
675
676 /* get the root inode */
677 inode = erofs_iget(sb, ROOT_NID(sbi), true);
678 if (IS_ERR(inode))
679 return PTR_ERR(inode);
680
681 if (!S_ISDIR(inode->i_mode)) {
682 erofs_err(sb, "rootino(nid %llu) is not a directory(i_mode %o)",
683 ROOT_NID(sbi), inode->i_mode);
684 iput(inode);
685 return -EINVAL;
686 }
687
688 sb->s_root = d_make_root(inode);
689 if (!sb->s_root)
690 return -ENOMEM;
691
692 erofs_shrinker_register(sb);
693 /* sb->s_umount is already locked, SB_ACTIVE and SB_BORN are not set */
694 err = erofs_init_managed_cache(sb);
695 if (err)
696 return err;
697
698 erofs_info(sb, "mounted with root inode @ nid %llu.", ROOT_NID(sbi));
699 return 0;
700 }
701
erofs_fc_get_tree(struct fs_context * fc)702 static int erofs_fc_get_tree(struct fs_context *fc)
703 {
704 return get_tree_bdev(fc, erofs_fc_fill_super);
705 }
706
erofs_fc_reconfigure(struct fs_context * fc)707 static int erofs_fc_reconfigure(struct fs_context *fc)
708 {
709 struct super_block *sb = fc->root->d_sb;
710 struct erofs_sb_info *sbi = EROFS_SB(sb);
711 struct erofs_fs_context *ctx = fc->fs_private;
712
713 DBG_BUGON(!sb_rdonly(sb));
714
715 if (test_opt(&ctx->opt, POSIX_ACL))
716 fc->sb_flags |= SB_POSIXACL;
717 else
718 fc->sb_flags &= ~SB_POSIXACL;
719
720 sbi->opt = ctx->opt;
721
722 fc->sb_flags |= SB_RDONLY;
723 return 0;
724 }
725
erofs_release_device_info(int id,void * ptr,void * data)726 static int erofs_release_device_info(int id, void *ptr, void *data)
727 {
728 struct erofs_device_info *dif = ptr;
729
730 fs_put_dax(dif->dax_dev);
731 if (dif->bdev)
732 blkdev_put(dif->bdev, FMODE_READ | FMODE_EXCL);
733 kfree(dif->path);
734 kfree(dif);
735 return 0;
736 }
737
erofs_free_dev_context(struct erofs_dev_context * devs)738 static void erofs_free_dev_context(struct erofs_dev_context *devs)
739 {
740 if (!devs)
741 return;
742 idr_for_each(&devs->tree, &erofs_release_device_info, NULL);
743 idr_destroy(&devs->tree);
744 kfree(devs);
745 }
746
erofs_fc_free(struct fs_context * fc)747 static void erofs_fc_free(struct fs_context *fc)
748 {
749 struct erofs_fs_context *ctx = fc->fs_private;
750
751 erofs_free_dev_context(ctx->devs);
752 kfree(ctx);
753 }
754
755 static const struct fs_context_operations erofs_context_ops = {
756 .parse_param = erofs_fc_parse_param,
757 .get_tree = erofs_fc_get_tree,
758 .reconfigure = erofs_fc_reconfigure,
759 .free = erofs_fc_free,
760 };
761
erofs_init_fs_context(struct fs_context * fc)762 static int erofs_init_fs_context(struct fs_context *fc)
763 {
764 struct erofs_fs_context *ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
765
766 if (!ctx)
767 return -ENOMEM;
768 ctx->devs = kzalloc(sizeof(struct erofs_dev_context), GFP_KERNEL);
769 if (!ctx->devs) {
770 kfree(ctx);
771 return -ENOMEM;
772 }
773 fc->fs_private = ctx;
774
775 idr_init(&ctx->devs->tree);
776 init_rwsem(&ctx->devs->rwsem);
777 erofs_default_options(ctx);
778 fc->ops = &erofs_context_ops;
779 return 0;
780 }
781
782 /*
783 * could be triggered after deactivate_locked_super()
784 * is called, thus including umount and failed to initialize.
785 */
erofs_kill_sb(struct super_block * sb)786 static void erofs_kill_sb(struct super_block *sb)
787 {
788 struct erofs_sb_info *sbi;
789
790 WARN_ON(sb->s_magic != EROFS_SUPER_MAGIC);
791
792 kill_block_super(sb);
793
794 sbi = EROFS_SB(sb);
795 if (!sbi)
796 return;
797
798 erofs_free_dev_context(sbi->devs);
799 fs_put_dax(sbi->dax_dev);
800 kfree(sbi);
801 sb->s_fs_info = NULL;
802 }
803
804 /* called when ->s_root is non-NULL */
erofs_put_super(struct super_block * sb)805 static void erofs_put_super(struct super_block *sb)
806 {
807 struct erofs_sb_info *const sbi = EROFS_SB(sb);
808
809 DBG_BUGON(!sbi);
810
811 erofs_shrinker_unregister(sb);
812 #ifdef CONFIG_EROFS_FS_ZIP
813 iput(sbi->managed_cache);
814 sbi->managed_cache = NULL;
815 #endif
816 }
817
818 static struct file_system_type erofs_fs_type = {
819 .owner = THIS_MODULE,
820 .name = "erofs",
821 .init_fs_context = erofs_init_fs_context,
822 .kill_sb = erofs_kill_sb,
823 .fs_flags = FS_REQUIRES_DEV,
824 };
825 MODULE_ALIAS_FS("erofs");
826
erofs_module_init(void)827 static int __init erofs_module_init(void)
828 {
829 int err;
830
831 erofs_check_ondisk_layout_definitions();
832
833 erofs_inode_cachep = kmem_cache_create("erofs_inode",
834 sizeof(struct erofs_inode), 0,
835 SLAB_RECLAIM_ACCOUNT,
836 erofs_inode_init_once);
837 if (!erofs_inode_cachep) {
838 err = -ENOMEM;
839 goto icache_err;
840 }
841
842 err = erofs_init_shrinker();
843 if (err)
844 goto shrinker_err;
845
846 err = z_erofs_lzma_init();
847 if (err)
848 goto lzma_err;
849
850 erofs_pcpubuf_init();
851 err = z_erofs_init_zip_subsystem();
852 if (err)
853 goto zip_err;
854
855 err = register_filesystem(&erofs_fs_type);
856 if (err)
857 goto fs_err;
858
859 return 0;
860
861 fs_err:
862 z_erofs_exit_zip_subsystem();
863 zip_err:
864 z_erofs_lzma_exit();
865 lzma_err:
866 erofs_exit_shrinker();
867 shrinker_err:
868 kmem_cache_destroy(erofs_inode_cachep);
869 icache_err:
870 return err;
871 }
872
erofs_module_exit(void)873 static void __exit erofs_module_exit(void)
874 {
875 unregister_filesystem(&erofs_fs_type);
876
877 /* Ensure all RCU free inodes / pclusters are safe to be destroyed. */
878 rcu_barrier();
879
880 z_erofs_exit_zip_subsystem();
881 z_erofs_lzma_exit();
882 erofs_exit_shrinker();
883 kmem_cache_destroy(erofs_inode_cachep);
884 erofs_pcpubuf_exit();
885 }
886
887 /* get filesystem statistics */
erofs_statfs(struct dentry * dentry,struct kstatfs * buf)888 static int erofs_statfs(struct dentry *dentry, struct kstatfs *buf)
889 {
890 struct super_block *sb = dentry->d_sb;
891 struct erofs_sb_info *sbi = EROFS_SB(sb);
892 u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
893
894 buf->f_type = sb->s_magic;
895 buf->f_bsize = EROFS_BLKSIZ;
896 buf->f_blocks = sbi->total_blocks;
897 buf->f_bfree = buf->f_bavail = 0;
898
899 buf->f_files = ULLONG_MAX;
900 buf->f_ffree = ULLONG_MAX - sbi->inos;
901
902 buf->f_namelen = EROFS_NAME_LEN;
903
904 buf->f_fsid = u64_to_fsid(id);
905 return 0;
906 }
907
erofs_show_options(struct seq_file * seq,struct dentry * root)908 static int erofs_show_options(struct seq_file *seq, struct dentry *root)
909 {
910 struct erofs_sb_info *sbi = EROFS_SB(root->d_sb);
911 struct erofs_mount_opts *opt = &sbi->opt;
912
913 #ifdef CONFIG_EROFS_FS_XATTR
914 if (test_opt(opt, XATTR_USER))
915 seq_puts(seq, ",user_xattr");
916 else
917 seq_puts(seq, ",nouser_xattr");
918 #endif
919 #ifdef CONFIG_EROFS_FS_POSIX_ACL
920 if (test_opt(opt, POSIX_ACL))
921 seq_puts(seq, ",acl");
922 else
923 seq_puts(seq, ",noacl");
924 #endif
925 #ifdef CONFIG_EROFS_FS_ZIP
926 if (opt->cache_strategy == EROFS_ZIP_CACHE_DISABLED)
927 seq_puts(seq, ",cache_strategy=disabled");
928 else if (opt->cache_strategy == EROFS_ZIP_CACHE_READAHEAD)
929 seq_puts(seq, ",cache_strategy=readahead");
930 else if (opt->cache_strategy == EROFS_ZIP_CACHE_READAROUND)
931 seq_puts(seq, ",cache_strategy=readaround");
932 #endif
933 if (test_opt(opt, DAX_ALWAYS))
934 seq_puts(seq, ",dax=always");
935 if (test_opt(opt, DAX_NEVER))
936 seq_puts(seq, ",dax=never");
937 return 0;
938 }
939
940 const struct super_operations erofs_sops = {
941 .put_super = erofs_put_super,
942 .alloc_inode = erofs_alloc_inode,
943 .free_inode = erofs_free_inode,
944 .statfs = erofs_statfs,
945 .show_options = erofs_show_options,
946 };
947
948 module_init(erofs_module_init);
949 module_exit(erofs_module_exit);
950
951 MODULE_DESCRIPTION("Enhanced ROM File System");
952 MODULE_AUTHOR("Gao Xiang, Chao Yu, Miao Xie, CONSUMER BG, HUAWEI Inc.");
953 MODULE_LICENSE("GPL");
954