1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Copyright (C) 2017-2018 HUAWEI, Inc.
4 * https://www.huawei.com/
5 * Created by Gao Xiang <gaoxiang25@huawei.com>
6 */
7 #include <linux/module.h>
8 #include <linux/buffer_head.h>
9 #include <linux/statfs.h>
10 #include <linux/parser.h>
11 #include <linux/seq_file.h>
12 #include <linux/crc32c.h>
13 #include <linux/fs_context.h>
14 #include <linux/fs_parser.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
erofs_read_superblock(struct super_block * sb)125 static int erofs_read_superblock(struct super_block *sb)
126 {
127 struct erofs_sb_info *sbi;
128 struct page *page;
129 struct erofs_super_block *dsb;
130 unsigned int blkszbits;
131 void *data;
132 int ret;
133
134 page = read_mapping_page(sb->s_bdev->bd_inode->i_mapping, 0, NULL);
135 if (IS_ERR(page)) {
136 erofs_err(sb, "cannot read erofs superblock");
137 return PTR_ERR(page);
138 }
139
140 sbi = EROFS_SB(sb);
141
142 data = kmap(page);
143 dsb = (struct erofs_super_block *)(data + EROFS_SUPER_OFFSET);
144
145 ret = -EINVAL;
146 if (le32_to_cpu(dsb->magic) != EROFS_SUPER_MAGIC_V1) {
147 erofs_err(sb, "cannot find valid erofs superblock");
148 goto out;
149 }
150
151 sbi->feature_compat = le32_to_cpu(dsb->feature_compat);
152 if (sbi->feature_compat & EROFS_FEATURE_COMPAT_SB_CHKSUM) {
153 ret = erofs_superblock_csum_verify(sb, data);
154 if (ret)
155 goto out;
156 }
157
158 blkszbits = dsb->blkszbits;
159 /* 9(512 bytes) + LOG_SECTORS_PER_BLOCK == LOG_BLOCK_SIZE */
160 if (blkszbits != LOG_BLOCK_SIZE) {
161 erofs_err(sb, "blksize %u isn't supported on this platform",
162 1 << blkszbits);
163 goto out;
164 }
165
166 if (!check_layout_compatibility(sb, dsb))
167 goto out;
168
169 sbi->blocks = le32_to_cpu(dsb->blocks);
170 sbi->meta_blkaddr = le32_to_cpu(dsb->meta_blkaddr);
171 #ifdef CONFIG_EROFS_FS_XATTR
172 sbi->xattr_blkaddr = le32_to_cpu(dsb->xattr_blkaddr);
173 #endif
174 sbi->islotbits = ilog2(sizeof(struct erofs_inode_compact));
175 sbi->root_nid = le16_to_cpu(dsb->root_nid);
176 sbi->inos = le64_to_cpu(dsb->inos);
177
178 sbi->build_time = le64_to_cpu(dsb->build_time);
179 sbi->build_time_nsec = le32_to_cpu(dsb->build_time_nsec);
180
181 memcpy(&sb->s_uuid, dsb->uuid, sizeof(dsb->uuid));
182
183 ret = strscpy(sbi->volume_name, dsb->volume_name,
184 sizeof(dsb->volume_name));
185 if (ret < 0) { /* -E2BIG */
186 erofs_err(sb, "bad volume name without NIL terminator");
187 ret = -EFSCORRUPTED;
188 goto out;
189 }
190 ret = 0;
191 out:
192 kunmap(page);
193 put_page(page);
194 return ret;
195 }
196
197 /* set up default EROFS parameters */
erofs_default_options(struct erofs_fs_context * ctx)198 static void erofs_default_options(struct erofs_fs_context *ctx)
199 {
200 #ifdef CONFIG_EROFS_FS_ZIP
201 ctx->cache_strategy = EROFS_ZIP_CACHE_READAROUND;
202 ctx->max_sync_decompress_pages = 3;
203 #endif
204 #ifdef CONFIG_EROFS_FS_XATTR
205 set_opt(ctx, XATTR_USER);
206 #endif
207 #ifdef CONFIG_EROFS_FS_POSIX_ACL
208 set_opt(ctx, POSIX_ACL);
209 #endif
210 }
211
212 enum {
213 Opt_user_xattr,
214 Opt_acl,
215 Opt_cache_strategy,
216 Opt_err
217 };
218
219 static const struct constant_table erofs_param_cache_strategy[] = {
220 {"disabled", EROFS_ZIP_CACHE_DISABLED},
221 {"readahead", EROFS_ZIP_CACHE_READAHEAD},
222 {"readaround", EROFS_ZIP_CACHE_READAROUND},
223 {}
224 };
225
226 static const struct fs_parameter_spec erofs_fs_parameters[] = {
227 fsparam_flag_no("user_xattr", Opt_user_xattr),
228 fsparam_flag_no("acl", Opt_acl),
229 fsparam_enum("cache_strategy", Opt_cache_strategy,
230 erofs_param_cache_strategy),
231 {}
232 };
233
erofs_fc_parse_param(struct fs_context * fc,struct fs_parameter * param)234 static int erofs_fc_parse_param(struct fs_context *fc,
235 struct fs_parameter *param)
236 {
237 struct erofs_fs_context *ctx __maybe_unused = fc->fs_private;
238 struct fs_parse_result result;
239 int opt;
240
241 opt = fs_parse(fc, erofs_fs_parameters, param, &result);
242 if (opt < 0)
243 return opt;
244
245 switch (opt) {
246 case Opt_user_xattr:
247 #ifdef CONFIG_EROFS_FS_XATTR
248 if (result.boolean)
249 set_opt(ctx, XATTR_USER);
250 else
251 clear_opt(ctx, XATTR_USER);
252 #else
253 errorfc(fc, "{,no}user_xattr options not supported");
254 #endif
255 break;
256 case Opt_acl:
257 #ifdef CONFIG_EROFS_FS_POSIX_ACL
258 if (result.boolean)
259 set_opt(ctx, POSIX_ACL);
260 else
261 clear_opt(ctx, POSIX_ACL);
262 #else
263 errorfc(fc, "{,no}acl options not supported");
264 #endif
265 break;
266 case Opt_cache_strategy:
267 #ifdef CONFIG_EROFS_FS_ZIP
268 ctx->cache_strategy = result.uint_32;
269 #else
270 errorfc(fc, "compression not supported, cache_strategy ignored");
271 #endif
272 break;
273 default:
274 return -ENOPARAM;
275 }
276 return 0;
277 }
278
279 #ifdef CONFIG_EROFS_FS_ZIP
280 static const struct address_space_operations managed_cache_aops;
281
erofs_managed_cache_releasepage(struct page * page,gfp_t gfp_mask)282 static int erofs_managed_cache_releasepage(struct page *page, gfp_t gfp_mask)
283 {
284 int ret = 1; /* 0 - busy */
285 struct address_space *const mapping = page->mapping;
286
287 DBG_BUGON(!PageLocked(page));
288 DBG_BUGON(mapping->a_ops != &managed_cache_aops);
289
290 if (PagePrivate(page))
291 ret = erofs_try_to_free_cached_page(mapping, page);
292
293 return ret;
294 }
295
erofs_managed_cache_invalidatepage(struct page * page,unsigned int offset,unsigned int length)296 static void erofs_managed_cache_invalidatepage(struct page *page,
297 unsigned int offset,
298 unsigned int length)
299 {
300 const unsigned int stop = length + offset;
301
302 DBG_BUGON(!PageLocked(page));
303
304 /* Check for potential overflow in debug mode */
305 DBG_BUGON(stop > PAGE_SIZE || stop < length);
306
307 if (offset == 0 && stop == PAGE_SIZE)
308 while (!erofs_managed_cache_releasepage(page, GFP_NOFS))
309 cond_resched();
310 }
311
312 static const struct address_space_operations managed_cache_aops = {
313 .releasepage = erofs_managed_cache_releasepage,
314 .invalidatepage = erofs_managed_cache_invalidatepage,
315 };
316
erofs_init_managed_cache(struct super_block * sb)317 static int erofs_init_managed_cache(struct super_block *sb)
318 {
319 struct erofs_sb_info *const sbi = EROFS_SB(sb);
320 struct inode *const inode = new_inode(sb);
321
322 if (!inode)
323 return -ENOMEM;
324
325 set_nlink(inode, 1);
326 inode->i_size = OFFSET_MAX;
327
328 inode->i_mapping->a_ops = &managed_cache_aops;
329 mapping_set_gfp_mask(inode->i_mapping,
330 GFP_NOFS | __GFP_HIGHMEM | __GFP_MOVABLE);
331 sbi->managed_cache = inode;
332 return 0;
333 }
334 #else
erofs_init_managed_cache(struct super_block * sb)335 static int erofs_init_managed_cache(struct super_block *sb) { return 0; }
336 #endif
337
erofs_fc_fill_super(struct super_block * sb,struct fs_context * fc)338 static int erofs_fc_fill_super(struct super_block *sb, struct fs_context *fc)
339 {
340 struct inode *inode;
341 struct erofs_sb_info *sbi;
342 struct erofs_fs_context *ctx = fc->fs_private;
343 int err;
344
345 sb->s_magic = EROFS_SUPER_MAGIC;
346
347 if (!sb_set_blocksize(sb, EROFS_BLKSIZ)) {
348 erofs_err(sb, "failed to set erofs blksize");
349 return -EINVAL;
350 }
351
352 sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
353 if (!sbi)
354 return -ENOMEM;
355
356 sb->s_fs_info = sbi;
357 err = erofs_read_superblock(sb);
358 if (err)
359 return err;
360
361 sb->s_flags |= SB_RDONLY | SB_NOATIME;
362 sb->s_maxbytes = MAX_LFS_FILESIZE;
363 sb->s_time_gran = 1;
364
365 sb->s_op = &erofs_sops;
366 sb->s_xattr = erofs_xattr_handlers;
367
368 if (test_opt(ctx, POSIX_ACL))
369 sb->s_flags |= SB_POSIXACL;
370 else
371 sb->s_flags &= ~SB_POSIXACL;
372
373 sbi->ctx = *ctx;
374
375 #ifdef CONFIG_EROFS_FS_ZIP
376 xa_init(&sbi->managed_pslots);
377 #endif
378
379 /* get the root inode */
380 inode = erofs_iget(sb, ROOT_NID(sbi), true);
381 if (IS_ERR(inode))
382 return PTR_ERR(inode);
383
384 if (!S_ISDIR(inode->i_mode)) {
385 erofs_err(sb, "rootino(nid %llu) is not a directory(i_mode %o)",
386 ROOT_NID(sbi), inode->i_mode);
387 iput(inode);
388 return -EINVAL;
389 }
390
391 sb->s_root = d_make_root(inode);
392 if (!sb->s_root)
393 return -ENOMEM;
394
395 erofs_shrinker_register(sb);
396 /* sb->s_umount is already locked, SB_ACTIVE and SB_BORN are not set */
397 err = erofs_init_managed_cache(sb);
398 if (err)
399 return err;
400
401 erofs_info(sb, "mounted with root inode @ nid %llu.", ROOT_NID(sbi));
402 return 0;
403 }
404
erofs_fc_get_tree(struct fs_context * fc)405 static int erofs_fc_get_tree(struct fs_context *fc)
406 {
407 return get_tree_bdev(fc, erofs_fc_fill_super);
408 }
409
erofs_fc_reconfigure(struct fs_context * fc)410 static int erofs_fc_reconfigure(struct fs_context *fc)
411 {
412 struct super_block *sb = fc->root->d_sb;
413 struct erofs_sb_info *sbi = EROFS_SB(sb);
414 struct erofs_fs_context *ctx = fc->fs_private;
415
416 DBG_BUGON(!sb_rdonly(sb));
417
418 if (test_opt(ctx, POSIX_ACL))
419 fc->sb_flags |= SB_POSIXACL;
420 else
421 fc->sb_flags &= ~SB_POSIXACL;
422
423 sbi->ctx = *ctx;
424
425 fc->sb_flags |= SB_RDONLY;
426 return 0;
427 }
428
erofs_fc_free(struct fs_context * fc)429 static void erofs_fc_free(struct fs_context *fc)
430 {
431 kfree(fc->fs_private);
432 }
433
434 static const struct fs_context_operations erofs_context_ops = {
435 .parse_param = erofs_fc_parse_param,
436 .get_tree = erofs_fc_get_tree,
437 .reconfigure = erofs_fc_reconfigure,
438 .free = erofs_fc_free,
439 };
440
erofs_init_fs_context(struct fs_context * fc)441 static int erofs_init_fs_context(struct fs_context *fc)
442 {
443 fc->fs_private = kzalloc(sizeof(struct erofs_fs_context), GFP_KERNEL);
444 if (!fc->fs_private)
445 return -ENOMEM;
446
447 /* set default mount options */
448 erofs_default_options(fc->fs_private);
449
450 fc->ops = &erofs_context_ops;
451
452 return 0;
453 }
454
455 /*
456 * could be triggered after deactivate_locked_super()
457 * is called, thus including umount and failed to initialize.
458 */
erofs_kill_sb(struct super_block * sb)459 static void erofs_kill_sb(struct super_block *sb)
460 {
461 struct erofs_sb_info *sbi;
462
463 WARN_ON(sb->s_magic != EROFS_SUPER_MAGIC);
464
465 kill_block_super(sb);
466
467 sbi = EROFS_SB(sb);
468 if (!sbi)
469 return;
470 kfree(sbi);
471 sb->s_fs_info = NULL;
472 }
473
474 /* called when ->s_root is non-NULL */
erofs_put_super(struct super_block * sb)475 static void erofs_put_super(struct super_block *sb)
476 {
477 struct erofs_sb_info *const sbi = EROFS_SB(sb);
478
479 DBG_BUGON(!sbi);
480
481 erofs_shrinker_unregister(sb);
482 #ifdef CONFIG_EROFS_FS_ZIP
483 iput(sbi->managed_cache);
484 sbi->managed_cache = NULL;
485 #endif
486 }
487
488 static struct file_system_type erofs_fs_type = {
489 .owner = THIS_MODULE,
490 .name = "erofs",
491 .init_fs_context = erofs_init_fs_context,
492 .kill_sb = erofs_kill_sb,
493 .fs_flags = FS_REQUIRES_DEV,
494 };
495 MODULE_ALIAS_FS("erofs");
496
erofs_module_init(void)497 static int __init erofs_module_init(void)
498 {
499 int err;
500
501 erofs_check_ondisk_layout_definitions();
502
503 erofs_inode_cachep = kmem_cache_create("erofs_inode",
504 sizeof(struct erofs_inode), 0,
505 SLAB_RECLAIM_ACCOUNT,
506 erofs_inode_init_once);
507 if (!erofs_inode_cachep) {
508 err = -ENOMEM;
509 goto icache_err;
510 }
511
512 err = erofs_init_shrinker();
513 if (err)
514 goto shrinker_err;
515
516 err = z_erofs_init_zip_subsystem();
517 if (err)
518 goto zip_err;
519
520 err = register_filesystem(&erofs_fs_type);
521 if (err)
522 goto fs_err;
523
524 return 0;
525
526 fs_err:
527 z_erofs_exit_zip_subsystem();
528 zip_err:
529 erofs_exit_shrinker();
530 shrinker_err:
531 kmem_cache_destroy(erofs_inode_cachep);
532 icache_err:
533 return err;
534 }
535
erofs_module_exit(void)536 static void __exit erofs_module_exit(void)
537 {
538 unregister_filesystem(&erofs_fs_type);
539 z_erofs_exit_zip_subsystem();
540 erofs_exit_shrinker();
541
542 /* Ensure all RCU free inodes are safe before cache is destroyed. */
543 rcu_barrier();
544 kmem_cache_destroy(erofs_inode_cachep);
545 }
546
547 /* get filesystem statistics */
erofs_statfs(struct dentry * dentry,struct kstatfs * buf)548 static int erofs_statfs(struct dentry *dentry, struct kstatfs *buf)
549 {
550 struct super_block *sb = dentry->d_sb;
551 struct erofs_sb_info *sbi = EROFS_SB(sb);
552 u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
553
554 buf->f_type = sb->s_magic;
555 buf->f_bsize = EROFS_BLKSIZ;
556 buf->f_blocks = sbi->blocks;
557 buf->f_bfree = buf->f_bavail = 0;
558
559 buf->f_files = ULLONG_MAX;
560 buf->f_ffree = ULLONG_MAX - sbi->inos;
561
562 buf->f_namelen = EROFS_NAME_LEN;
563
564 buf->f_fsid = u64_to_fsid(id);
565 return 0;
566 }
567
erofs_show_options(struct seq_file * seq,struct dentry * root)568 static int erofs_show_options(struct seq_file *seq, struct dentry *root)
569 {
570 struct erofs_sb_info *sbi __maybe_unused = EROFS_SB(root->d_sb);
571 struct erofs_fs_context *ctx __maybe_unused = &sbi->ctx;
572
573 #ifdef CONFIG_EROFS_FS_XATTR
574 if (test_opt(ctx, XATTR_USER))
575 seq_puts(seq, ",user_xattr");
576 else
577 seq_puts(seq, ",nouser_xattr");
578 #endif
579 #ifdef CONFIG_EROFS_FS_POSIX_ACL
580 if (test_opt(ctx, POSIX_ACL))
581 seq_puts(seq, ",acl");
582 else
583 seq_puts(seq, ",noacl");
584 #endif
585 #ifdef CONFIG_EROFS_FS_ZIP
586 if (ctx->cache_strategy == EROFS_ZIP_CACHE_DISABLED)
587 seq_puts(seq, ",cache_strategy=disabled");
588 else if (ctx->cache_strategy == EROFS_ZIP_CACHE_READAHEAD)
589 seq_puts(seq, ",cache_strategy=readahead");
590 else if (ctx->cache_strategy == EROFS_ZIP_CACHE_READAROUND)
591 seq_puts(seq, ",cache_strategy=readaround");
592 #endif
593 return 0;
594 }
595
596 const struct super_operations erofs_sops = {
597 .put_super = erofs_put_super,
598 .alloc_inode = erofs_alloc_inode,
599 .free_inode = erofs_free_inode,
600 .statfs = erofs_statfs,
601 .show_options = erofs_show_options,
602 };
603
604 module_init(erofs_module_init);
605 module_exit(erofs_module_exit);
606
607 MODULE_DESCRIPTION("Enhanced ROM File System");
608 MODULE_AUTHOR("Gao Xiang, Chao Yu, Miao Xie, CONSUMER BG, HUAWEI Inc.");
609 MODULE_LICENSE("GPL");
610
611