1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Copyright (C) 2017-2018 HUAWEI, Inc.
4 * https://www.huawei.com/
5 * Copyright (C) 2021, Alibaba Cloud
6 */
7 #include <linux/module.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 <linux/exportfs.h>
16 #include "xattr.h"
17
18 #define CREATE_TRACE_POINTS
19 #include <trace/events/erofs.h>
20
21 static struct kmem_cache *erofs_inode_cachep __read_mostly;
22
_erofs_err(struct super_block * sb,const char * func,const char * fmt,...)23 void _erofs_err(struct super_block *sb, const char *func, 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, func, &vaf);
34 va_end(args);
35 }
36
_erofs_info(struct super_block * sb,const char * func,const char * fmt,...)37 void _erofs_info(struct super_block *sb, const char *func, const char *fmt, ...)
38 {
39 struct va_format vaf;
40 va_list args;
41
42 va_start(args, fmt);
43
44 vaf.fmt = fmt;
45 vaf.va = &args;
46
47 pr_info("(device %s): %pV", sb->s_id, &vaf);
48 va_end(args);
49 }
50
erofs_superblock_csum_verify(struct super_block * sb,void * sbdata)51 static int erofs_superblock_csum_verify(struct super_block *sb, void *sbdata)
52 {
53 size_t len = 1 << EROFS_SB(sb)->blkszbits;
54 struct erofs_super_block *dsb;
55 u32 expected_crc, crc;
56
57 if (len > EROFS_SUPER_OFFSET)
58 len -= EROFS_SUPER_OFFSET;
59
60 dsb = kmemdup(sbdata + EROFS_SUPER_OFFSET, len, GFP_KERNEL);
61 if (!dsb)
62 return -ENOMEM;
63
64 expected_crc = le32_to_cpu(dsb->checksum);
65 dsb->checksum = 0;
66 /* to allow for x86 boot sectors and other oddities. */
67 crc = crc32c(~0, dsb, len);
68 kfree(dsb);
69
70 if (crc != expected_crc) {
71 erofs_err(sb, "invalid checksum 0x%08x, 0x%08x expected",
72 crc, expected_crc);
73 return -EBADMSG;
74 }
75 return 0;
76 }
77
erofs_inode_init_once(void * ptr)78 static void erofs_inode_init_once(void *ptr)
79 {
80 struct erofs_inode *vi = ptr;
81
82 inode_init_once(&vi->vfs_inode);
83 }
84
erofs_alloc_inode(struct super_block * sb)85 static struct inode *erofs_alloc_inode(struct super_block *sb)
86 {
87 struct erofs_inode *vi =
88 alloc_inode_sb(sb, erofs_inode_cachep, GFP_KERNEL);
89
90 if (!vi)
91 return NULL;
92
93 /* zero out everything except vfs_inode */
94 memset(vi, 0, offsetof(struct erofs_inode, vfs_inode));
95 return &vi->vfs_inode;
96 }
97
erofs_free_inode(struct inode * inode)98 static void erofs_free_inode(struct inode *inode)
99 {
100 struct erofs_inode *vi = EROFS_I(inode);
101
102 if (inode->i_op == &erofs_fast_symlink_iops)
103 kfree(inode->i_link);
104 kfree(vi->xattr_shared_xattrs);
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, "unidentified incompatible feature %x, please upgrade kernel",
118 feature & ~EROFS_ALL_FEATURE_INCOMPAT);
119 return false;
120 }
121 return true;
122 }
123
124 /* read variable-sized metadata, offset will be aligned by 4-byte */
erofs_read_metadata(struct super_block * sb,struct erofs_buf * buf,erofs_off_t * offset,int * lengthp)125 void *erofs_read_metadata(struct super_block *sb, struct erofs_buf *buf,
126 erofs_off_t *offset, int *lengthp)
127 {
128 u8 *buffer, *ptr;
129 int len, i, cnt;
130
131 *offset = round_up(*offset, 4);
132 ptr = erofs_bread(buf, erofs_blknr(sb, *offset), EROFS_KMAP);
133 if (IS_ERR(ptr))
134 return ptr;
135
136 len = le16_to_cpu(*(__le16 *)&ptr[erofs_blkoff(sb, *offset)]);
137 if (!len)
138 len = U16_MAX + 1;
139 buffer = kmalloc(len, GFP_KERNEL);
140 if (!buffer)
141 return ERR_PTR(-ENOMEM);
142 *offset += sizeof(__le16);
143 *lengthp = len;
144
145 for (i = 0; i < len; i += cnt) {
146 cnt = min_t(int, sb->s_blocksize - erofs_blkoff(sb, *offset),
147 len - i);
148 ptr = erofs_bread(buf, erofs_blknr(sb, *offset), EROFS_KMAP);
149 if (IS_ERR(ptr)) {
150 kfree(buffer);
151 return ptr;
152 }
153 memcpy(buffer + i, ptr + erofs_blkoff(sb, *offset), cnt);
154 *offset += cnt;
155 }
156 return buffer;
157 }
158
159 #ifdef CONFIG_EROFS_FS_ZIP
erofs_load_compr_cfgs(struct super_block * sb,struct erofs_super_block * dsb)160 static int erofs_load_compr_cfgs(struct super_block *sb,
161 struct erofs_super_block *dsb)
162 {
163 struct erofs_sb_info *sbi = EROFS_SB(sb);
164 struct erofs_buf buf = __EROFS_BUF_INITIALIZER;
165 unsigned int algs, alg;
166 erofs_off_t offset;
167 int size, ret = 0;
168
169 sbi->available_compr_algs = le16_to_cpu(dsb->u1.available_compr_algs);
170 if (sbi->available_compr_algs & ~Z_EROFS_ALL_COMPR_ALGS) {
171 erofs_err(sb, "try to load compressed fs with unsupported algorithms %x",
172 sbi->available_compr_algs & ~Z_EROFS_ALL_COMPR_ALGS);
173 return -EINVAL;
174 }
175
176 erofs_init_metabuf(&buf, sb);
177 offset = EROFS_SUPER_OFFSET + sbi->sb_size;
178 alg = 0;
179 for (algs = sbi->available_compr_algs; algs; algs >>= 1, ++alg) {
180 void *data;
181
182 if (!(algs & 1))
183 continue;
184
185 data = erofs_read_metadata(sb, &buf, &offset, &size);
186 if (IS_ERR(data)) {
187 ret = PTR_ERR(data);
188 break;
189 }
190
191 switch (alg) {
192 case Z_EROFS_COMPRESSION_LZ4:
193 ret = z_erofs_load_lz4_config(sb, dsb, data, size);
194 break;
195 case Z_EROFS_COMPRESSION_LZMA:
196 ret = z_erofs_load_lzma_config(sb, dsb, data, size);
197 break;
198 case Z_EROFS_COMPRESSION_DEFLATE:
199 ret = z_erofs_load_deflate_config(sb, dsb, data, size);
200 break;
201 default:
202 DBG_BUGON(1);
203 ret = -EFAULT;
204 }
205 kfree(data);
206 if (ret)
207 break;
208 }
209 erofs_put_metabuf(&buf);
210 return ret;
211 }
212 #else
erofs_load_compr_cfgs(struct super_block * sb,struct erofs_super_block * dsb)213 static int erofs_load_compr_cfgs(struct super_block *sb,
214 struct erofs_super_block *dsb)
215 {
216 if (dsb->u1.available_compr_algs) {
217 erofs_err(sb, "try to load compressed fs when compression is disabled");
218 return -EINVAL;
219 }
220 return 0;
221 }
222 #endif
223
erofs_init_device(struct erofs_buf * buf,struct super_block * sb,struct erofs_device_info * dif,erofs_off_t * pos)224 static int erofs_init_device(struct erofs_buf *buf, struct super_block *sb,
225 struct erofs_device_info *dif, erofs_off_t *pos)
226 {
227 struct erofs_sb_info *sbi = EROFS_SB(sb);
228 struct erofs_fscache *fscache;
229 struct erofs_deviceslot *dis;
230 struct block_device *bdev;
231 void *ptr;
232
233 ptr = erofs_read_metabuf(buf, sb, erofs_blknr(sb, *pos), EROFS_KMAP);
234 if (IS_ERR(ptr))
235 return PTR_ERR(ptr);
236 dis = ptr + erofs_blkoff(sb, *pos);
237
238 if (!sbi->devs->flatdev && !dif->path) {
239 if (!dis->tag[0]) {
240 erofs_err(sb, "empty device tag @ pos %llu", *pos);
241 return -EINVAL;
242 }
243 dif->path = kmemdup_nul(dis->tag, sizeof(dis->tag), GFP_KERNEL);
244 if (!dif->path)
245 return -ENOMEM;
246 }
247
248 if (erofs_is_fscache_mode(sb)) {
249 fscache = erofs_fscache_register_cookie(sb, dif->path, 0);
250 if (IS_ERR(fscache))
251 return PTR_ERR(fscache);
252 dif->fscache = fscache;
253 } else if (!sbi->devs->flatdev) {
254 bdev = blkdev_get_by_path(dif->path, BLK_OPEN_READ, sb->s_type,
255 NULL);
256 if (IS_ERR(bdev))
257 return PTR_ERR(bdev);
258 dif->bdev = bdev;
259 dif->dax_dev = fs_dax_get_by_bdev(bdev, &dif->dax_part_off,
260 NULL, NULL);
261 }
262
263 dif->blocks = le32_to_cpu(dis->blocks);
264 dif->mapped_blkaddr = le32_to_cpu(dis->mapped_blkaddr);
265 sbi->total_blocks += dif->blocks;
266 *pos += EROFS_DEVT_SLOT_SIZE;
267 return 0;
268 }
269
erofs_scan_devices(struct super_block * sb,struct erofs_super_block * dsb)270 static int erofs_scan_devices(struct super_block *sb,
271 struct erofs_super_block *dsb)
272 {
273 struct erofs_sb_info *sbi = EROFS_SB(sb);
274 unsigned int ondisk_extradevs;
275 erofs_off_t pos;
276 struct erofs_buf buf = __EROFS_BUF_INITIALIZER;
277 struct erofs_device_info *dif;
278 int id, err = 0;
279
280 sbi->total_blocks = sbi->primarydevice_blocks;
281 if (!erofs_sb_has_device_table(sbi))
282 ondisk_extradevs = 0;
283 else
284 ondisk_extradevs = le16_to_cpu(dsb->extra_devices);
285
286 if (sbi->devs->extra_devices &&
287 ondisk_extradevs != sbi->devs->extra_devices) {
288 erofs_err(sb, "extra devices don't match (ondisk %u, given %u)",
289 ondisk_extradevs, sbi->devs->extra_devices);
290 return -EINVAL;
291 }
292 if (!ondisk_extradevs)
293 return 0;
294
295 if (!sbi->devs->extra_devices && !erofs_is_fscache_mode(sb))
296 sbi->devs->flatdev = true;
297
298 sbi->device_id_mask = roundup_pow_of_two(ondisk_extradevs + 1) - 1;
299 pos = le16_to_cpu(dsb->devt_slotoff) * EROFS_DEVT_SLOT_SIZE;
300 down_read(&sbi->devs->rwsem);
301 if (sbi->devs->extra_devices) {
302 idr_for_each_entry(&sbi->devs->tree, dif, id) {
303 err = erofs_init_device(&buf, sb, dif, &pos);
304 if (err)
305 break;
306 }
307 } else {
308 for (id = 0; id < ondisk_extradevs; id++) {
309 dif = kzalloc(sizeof(*dif), GFP_KERNEL);
310 if (!dif) {
311 err = -ENOMEM;
312 break;
313 }
314
315 err = idr_alloc(&sbi->devs->tree, dif, 0, 0, GFP_KERNEL);
316 if (err < 0) {
317 kfree(dif);
318 break;
319 }
320 ++sbi->devs->extra_devices;
321
322 err = erofs_init_device(&buf, sb, dif, &pos);
323 if (err)
324 break;
325 }
326 }
327 up_read(&sbi->devs->rwsem);
328 erofs_put_metabuf(&buf);
329 return err;
330 }
331
erofs_read_superblock(struct super_block * sb)332 static int erofs_read_superblock(struct super_block *sb)
333 {
334 struct erofs_sb_info *sbi;
335 struct erofs_buf buf = __EROFS_BUF_INITIALIZER;
336 struct erofs_super_block *dsb;
337 void *data;
338 int ret;
339
340 data = erofs_read_metabuf(&buf, sb, 0, EROFS_KMAP);
341 if (IS_ERR(data)) {
342 erofs_err(sb, "cannot read erofs superblock");
343 return PTR_ERR(data);
344 }
345
346 sbi = EROFS_SB(sb);
347 dsb = (struct erofs_super_block *)(data + EROFS_SUPER_OFFSET);
348
349 ret = -EINVAL;
350 if (le32_to_cpu(dsb->magic) != EROFS_SUPER_MAGIC_V1) {
351 erofs_err(sb, "cannot find valid erofs superblock");
352 goto out;
353 }
354
355 sbi->blkszbits = dsb->blkszbits;
356 if (sbi->blkszbits < 9 || sbi->blkszbits > PAGE_SHIFT) {
357 erofs_err(sb, "blkszbits %u isn't supported", sbi->blkszbits);
358 goto out;
359 }
360 if (dsb->dirblkbits) {
361 erofs_err(sb, "dirblkbits %u isn't supported", dsb->dirblkbits);
362 goto out;
363 }
364
365 sbi->feature_compat = le32_to_cpu(dsb->feature_compat);
366 if (erofs_sb_has_sb_chksum(sbi)) {
367 ret = erofs_superblock_csum_verify(sb, data);
368 if (ret)
369 goto out;
370 }
371
372 ret = -EINVAL;
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 > PAGE_SIZE - EROFS_SUPER_OFFSET) {
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 sbi->xattr_prefix_start = le32_to_cpu(dsb->xattr_prefix_start);
387 sbi->xattr_prefix_count = dsb->xattr_prefix_count;
388 sbi->xattr_filter_reserved = dsb->xattr_filter_reserved;
389 #endif
390 sbi->islotbits = ilog2(sizeof(struct erofs_inode_compact));
391 sbi->root_nid = le16_to_cpu(dsb->root_nid);
392 sbi->packed_nid = le64_to_cpu(dsb->packed_nid);
393 sbi->inos = le64_to_cpu(dsb->inos);
394
395 sbi->build_time = le64_to_cpu(dsb->build_time);
396 sbi->build_time_nsec = le32_to_cpu(dsb->build_time_nsec);
397
398 memcpy(&sb->s_uuid, dsb->uuid, sizeof(dsb->uuid));
399
400 ret = strscpy(sbi->volume_name, dsb->volume_name,
401 sizeof(dsb->volume_name));
402 if (ret < 0) { /* -E2BIG */
403 erofs_err(sb, "bad volume name without NIL terminator");
404 ret = -EFSCORRUPTED;
405 goto out;
406 }
407
408 /* parse on-disk compression configurations */
409 if (erofs_sb_has_compr_cfgs(sbi))
410 ret = erofs_load_compr_cfgs(sb, dsb);
411 else
412 ret = z_erofs_load_lz4_config(sb, dsb, NULL, 0);
413 if (ret < 0)
414 goto out;
415
416 /* handle multiple devices */
417 ret = erofs_scan_devices(sb, dsb);
418
419 if (erofs_is_fscache_mode(sb))
420 erofs_info(sb, "EXPERIMENTAL fscache-based on-demand read feature in use. Use at your own risk!");
421 out:
422 erofs_put_metabuf(&buf);
423 return ret;
424 }
425
erofs_default_options(struct erofs_fs_context * ctx)426 static void erofs_default_options(struct erofs_fs_context *ctx)
427 {
428 #ifdef CONFIG_EROFS_FS_ZIP
429 ctx->opt.cache_strategy = EROFS_ZIP_CACHE_READAROUND;
430 ctx->opt.max_sync_decompress_pages = 3;
431 ctx->opt.sync_decompress = EROFS_SYNC_DECOMPRESS_AUTO;
432 #endif
433 #ifdef CONFIG_EROFS_FS_XATTR
434 set_opt(&ctx->opt, XATTR_USER);
435 #endif
436 #ifdef CONFIG_EROFS_FS_POSIX_ACL
437 set_opt(&ctx->opt, POSIX_ACL);
438 #endif
439 }
440
441 enum {
442 Opt_user_xattr,
443 Opt_acl,
444 Opt_cache_strategy,
445 Opt_dax,
446 Opt_dax_enum,
447 Opt_device,
448 Opt_fsid,
449 Opt_domain_id,
450 Opt_err
451 };
452
453 static const struct constant_table erofs_param_cache_strategy[] = {
454 {"disabled", EROFS_ZIP_CACHE_DISABLED},
455 {"readahead", EROFS_ZIP_CACHE_READAHEAD},
456 {"readaround", EROFS_ZIP_CACHE_READAROUND},
457 {}
458 };
459
460 static const struct constant_table erofs_dax_param_enums[] = {
461 {"always", EROFS_MOUNT_DAX_ALWAYS},
462 {"never", EROFS_MOUNT_DAX_NEVER},
463 {}
464 };
465
466 static const struct fs_parameter_spec erofs_fs_parameters[] = {
467 fsparam_flag_no("user_xattr", Opt_user_xattr),
468 fsparam_flag_no("acl", Opt_acl),
469 fsparam_enum("cache_strategy", Opt_cache_strategy,
470 erofs_param_cache_strategy),
471 fsparam_flag("dax", Opt_dax),
472 fsparam_enum("dax", Opt_dax_enum, erofs_dax_param_enums),
473 fsparam_string("device", Opt_device),
474 fsparam_string("fsid", Opt_fsid),
475 fsparam_string("domain_id", Opt_domain_id),
476 {}
477 };
478
erofs_fc_set_dax_mode(struct fs_context * fc,unsigned int mode)479 static bool erofs_fc_set_dax_mode(struct fs_context *fc, unsigned int mode)
480 {
481 #ifdef CONFIG_FS_DAX
482 struct erofs_fs_context *ctx = fc->fs_private;
483
484 switch (mode) {
485 case EROFS_MOUNT_DAX_ALWAYS:
486 warnfc(fc, "DAX enabled. Warning: EXPERIMENTAL, use at your own risk");
487 set_opt(&ctx->opt, DAX_ALWAYS);
488 clear_opt(&ctx->opt, DAX_NEVER);
489 return true;
490 case EROFS_MOUNT_DAX_NEVER:
491 set_opt(&ctx->opt, DAX_NEVER);
492 clear_opt(&ctx->opt, DAX_ALWAYS);
493 return true;
494 default:
495 DBG_BUGON(1);
496 return false;
497 }
498 #else
499 errorfc(fc, "dax options not supported");
500 return false;
501 #endif
502 }
503
erofs_fc_parse_param(struct fs_context * fc,struct fs_parameter * param)504 static int erofs_fc_parse_param(struct fs_context *fc,
505 struct fs_parameter *param)
506 {
507 struct erofs_fs_context *ctx = fc->fs_private;
508 struct fs_parse_result result;
509 struct erofs_device_info *dif;
510 int opt, ret;
511
512 opt = fs_parse(fc, erofs_fs_parameters, param, &result);
513 if (opt < 0)
514 return opt;
515
516 switch (opt) {
517 case Opt_user_xattr:
518 #ifdef CONFIG_EROFS_FS_XATTR
519 if (result.boolean)
520 set_opt(&ctx->opt, XATTR_USER);
521 else
522 clear_opt(&ctx->opt, XATTR_USER);
523 #else
524 errorfc(fc, "{,no}user_xattr options not supported");
525 #endif
526 break;
527 case Opt_acl:
528 #ifdef CONFIG_EROFS_FS_POSIX_ACL
529 if (result.boolean)
530 set_opt(&ctx->opt, POSIX_ACL);
531 else
532 clear_opt(&ctx->opt, POSIX_ACL);
533 #else
534 errorfc(fc, "{,no}acl options not supported");
535 #endif
536 break;
537 case Opt_cache_strategy:
538 #ifdef CONFIG_EROFS_FS_ZIP
539 ctx->opt.cache_strategy = result.uint_32;
540 #else
541 errorfc(fc, "compression not supported, cache_strategy ignored");
542 #endif
543 break;
544 case Opt_dax:
545 if (!erofs_fc_set_dax_mode(fc, EROFS_MOUNT_DAX_ALWAYS))
546 return -EINVAL;
547 break;
548 case Opt_dax_enum:
549 if (!erofs_fc_set_dax_mode(fc, result.uint_32))
550 return -EINVAL;
551 break;
552 case Opt_device:
553 dif = kzalloc(sizeof(*dif), GFP_KERNEL);
554 if (!dif)
555 return -ENOMEM;
556 dif->path = kstrdup(param->string, GFP_KERNEL);
557 if (!dif->path) {
558 kfree(dif);
559 return -ENOMEM;
560 }
561 down_write(&ctx->devs->rwsem);
562 ret = idr_alloc(&ctx->devs->tree, dif, 0, 0, GFP_KERNEL);
563 up_write(&ctx->devs->rwsem);
564 if (ret < 0) {
565 kfree(dif->path);
566 kfree(dif);
567 return ret;
568 }
569 ++ctx->devs->extra_devices;
570 break;
571 #ifdef CONFIG_EROFS_FS_ONDEMAND
572 case Opt_fsid:
573 kfree(ctx->fsid);
574 ctx->fsid = kstrdup(param->string, GFP_KERNEL);
575 if (!ctx->fsid)
576 return -ENOMEM;
577 break;
578 case Opt_domain_id:
579 kfree(ctx->domain_id);
580 ctx->domain_id = kstrdup(param->string, GFP_KERNEL);
581 if (!ctx->domain_id)
582 return -ENOMEM;
583 break;
584 #else
585 case Opt_fsid:
586 case Opt_domain_id:
587 errorfc(fc, "%s option not supported", erofs_fs_parameters[opt].name);
588 break;
589 #endif
590 default:
591 return -ENOPARAM;
592 }
593 return 0;
594 }
595
erofs_nfs_get_inode(struct super_block * sb,u64 ino,u32 generation)596 static struct inode *erofs_nfs_get_inode(struct super_block *sb,
597 u64 ino, u32 generation)
598 {
599 return erofs_iget(sb, ino);
600 }
601
erofs_fh_to_dentry(struct super_block * sb,struct fid * fid,int fh_len,int fh_type)602 static struct dentry *erofs_fh_to_dentry(struct super_block *sb,
603 struct fid *fid, int fh_len, int fh_type)
604 {
605 return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
606 erofs_nfs_get_inode);
607 }
608
erofs_fh_to_parent(struct super_block * sb,struct fid * fid,int fh_len,int fh_type)609 static struct dentry *erofs_fh_to_parent(struct super_block *sb,
610 struct fid *fid, int fh_len, int fh_type)
611 {
612 return generic_fh_to_parent(sb, fid, fh_len, fh_type,
613 erofs_nfs_get_inode);
614 }
615
erofs_get_parent(struct dentry * child)616 static struct dentry *erofs_get_parent(struct dentry *child)
617 {
618 erofs_nid_t nid;
619 unsigned int d_type;
620 int err;
621
622 err = erofs_namei(d_inode(child), &dotdot_name, &nid, &d_type);
623 if (err)
624 return ERR_PTR(err);
625 return d_obtain_alias(erofs_iget(child->d_sb, nid));
626 }
627
628 static const struct export_operations erofs_export_ops = {
629 .fh_to_dentry = erofs_fh_to_dentry,
630 .fh_to_parent = erofs_fh_to_parent,
631 .get_parent = erofs_get_parent,
632 };
633
erofs_fc_fill_pseudo_super(struct super_block * sb,struct fs_context * fc)634 static int erofs_fc_fill_pseudo_super(struct super_block *sb, struct fs_context *fc)
635 {
636 static const struct tree_descr empty_descr = {""};
637
638 return simple_fill_super(sb, EROFS_SUPER_MAGIC, &empty_descr);
639 }
640
erofs_fc_fill_super(struct super_block * sb,struct fs_context * fc)641 static int erofs_fc_fill_super(struct super_block *sb, struct fs_context *fc)
642 {
643 struct inode *inode;
644 struct erofs_sb_info *sbi;
645 struct erofs_fs_context *ctx = fc->fs_private;
646 int err;
647
648 sb->s_magic = EROFS_SUPER_MAGIC;
649 sb->s_flags |= SB_RDONLY | SB_NOATIME;
650 sb->s_maxbytes = MAX_LFS_FILESIZE;
651 sb->s_op = &erofs_sops;
652
653 sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
654 if (!sbi)
655 return -ENOMEM;
656
657 sb->s_fs_info = sbi;
658 sbi->opt = ctx->opt;
659 sbi->devs = ctx->devs;
660 ctx->devs = NULL;
661 sbi->fsid = ctx->fsid;
662 ctx->fsid = NULL;
663 sbi->domain_id = ctx->domain_id;
664 ctx->domain_id = NULL;
665
666 sbi->blkszbits = PAGE_SHIFT;
667 if (erofs_is_fscache_mode(sb)) {
668 sb->s_blocksize = PAGE_SIZE;
669 sb->s_blocksize_bits = PAGE_SHIFT;
670
671 err = erofs_fscache_register_fs(sb);
672 if (err)
673 return err;
674
675 err = super_setup_bdi(sb);
676 if (err)
677 return err;
678 } else {
679 if (!sb_set_blocksize(sb, PAGE_SIZE)) {
680 errorfc(fc, "failed to set initial blksize");
681 return -EINVAL;
682 }
683
684 sbi->dax_dev = fs_dax_get_by_bdev(sb->s_bdev,
685 &sbi->dax_part_off,
686 NULL, NULL);
687 }
688
689 err = erofs_read_superblock(sb);
690 if (err)
691 return err;
692
693 if (sb->s_blocksize_bits != sbi->blkszbits) {
694 if (erofs_is_fscache_mode(sb)) {
695 errorfc(fc, "unsupported blksize for fscache mode");
696 return -EINVAL;
697 }
698 if (!sb_set_blocksize(sb, 1 << sbi->blkszbits)) {
699 errorfc(fc, "failed to set erofs blksize");
700 return -EINVAL;
701 }
702 }
703
704 if (test_opt(&sbi->opt, DAX_ALWAYS)) {
705 if (!sbi->dax_dev) {
706 errorfc(fc, "DAX unsupported by block device. Turning off DAX.");
707 clear_opt(&sbi->opt, DAX_ALWAYS);
708 } else if (sbi->blkszbits != PAGE_SHIFT) {
709 errorfc(fc, "unsupported blocksize for DAX");
710 clear_opt(&sbi->opt, DAX_ALWAYS);
711 }
712 }
713
714 sb->s_time_gran = 1;
715 sb->s_xattr = erofs_xattr_handlers;
716 sb->s_export_op = &erofs_export_ops;
717
718 if (test_opt(&sbi->opt, POSIX_ACL))
719 sb->s_flags |= SB_POSIXACL;
720 else
721 sb->s_flags &= ~SB_POSIXACL;
722
723 #ifdef CONFIG_EROFS_FS_ZIP
724 xa_init(&sbi->managed_pslots);
725 #endif
726
727 inode = erofs_iget(sb, ROOT_NID(sbi));
728 if (IS_ERR(inode))
729 return PTR_ERR(inode);
730
731 if (!S_ISDIR(inode->i_mode)) {
732 erofs_err(sb, "rootino(nid %llu) is not a directory(i_mode %o)",
733 ROOT_NID(sbi), inode->i_mode);
734 iput(inode);
735 return -EINVAL;
736 }
737
738 sb->s_root = d_make_root(inode);
739 if (!sb->s_root)
740 return -ENOMEM;
741
742 erofs_shrinker_register(sb);
743 if (erofs_sb_has_fragments(sbi) && sbi->packed_nid) {
744 sbi->packed_inode = erofs_iget(sb, sbi->packed_nid);
745 if (IS_ERR(sbi->packed_inode)) {
746 err = PTR_ERR(sbi->packed_inode);
747 sbi->packed_inode = NULL;
748 return err;
749 }
750 }
751 err = erofs_init_managed_cache(sb);
752 if (err)
753 return err;
754
755 err = erofs_xattr_prefixes_init(sb);
756 if (err)
757 return err;
758
759 err = erofs_register_sysfs(sb);
760 if (err)
761 return err;
762
763 erofs_info(sb, "mounted with root inode @ nid %llu.", ROOT_NID(sbi));
764 return 0;
765 }
766
erofs_fc_anon_get_tree(struct fs_context * fc)767 static int erofs_fc_anon_get_tree(struct fs_context *fc)
768 {
769 return get_tree_nodev(fc, erofs_fc_fill_pseudo_super);
770 }
771
erofs_fc_get_tree(struct fs_context * fc)772 static int erofs_fc_get_tree(struct fs_context *fc)
773 {
774 struct erofs_fs_context *ctx = fc->fs_private;
775
776 if (IS_ENABLED(CONFIG_EROFS_FS_ONDEMAND) && ctx->fsid)
777 return get_tree_nodev(fc, erofs_fc_fill_super);
778
779 return get_tree_bdev(fc, erofs_fc_fill_super);
780 }
781
erofs_fc_reconfigure(struct fs_context * fc)782 static int erofs_fc_reconfigure(struct fs_context *fc)
783 {
784 struct super_block *sb = fc->root->d_sb;
785 struct erofs_sb_info *sbi = EROFS_SB(sb);
786 struct erofs_fs_context *ctx = fc->fs_private;
787
788 DBG_BUGON(!sb_rdonly(sb));
789
790 if (ctx->fsid || ctx->domain_id)
791 erofs_info(sb, "ignoring reconfiguration for fsid|domain_id.");
792
793 if (test_opt(&ctx->opt, POSIX_ACL))
794 fc->sb_flags |= SB_POSIXACL;
795 else
796 fc->sb_flags &= ~SB_POSIXACL;
797
798 sbi->opt = ctx->opt;
799
800 fc->sb_flags |= SB_RDONLY;
801 return 0;
802 }
803
erofs_release_device_info(int id,void * ptr,void * data)804 static int erofs_release_device_info(int id, void *ptr, void *data)
805 {
806 struct erofs_device_info *dif = ptr;
807
808 fs_put_dax(dif->dax_dev, NULL);
809 if (dif->bdev)
810 blkdev_put(dif->bdev, &erofs_fs_type);
811 erofs_fscache_unregister_cookie(dif->fscache);
812 dif->fscache = NULL;
813 kfree(dif->path);
814 kfree(dif);
815 return 0;
816 }
817
erofs_free_dev_context(struct erofs_dev_context * devs)818 static void erofs_free_dev_context(struct erofs_dev_context *devs)
819 {
820 if (!devs)
821 return;
822 idr_for_each(&devs->tree, &erofs_release_device_info, NULL);
823 idr_destroy(&devs->tree);
824 kfree(devs);
825 }
826
erofs_fc_free(struct fs_context * fc)827 static void erofs_fc_free(struct fs_context *fc)
828 {
829 struct erofs_fs_context *ctx = fc->fs_private;
830
831 erofs_free_dev_context(ctx->devs);
832 kfree(ctx->fsid);
833 kfree(ctx->domain_id);
834 kfree(ctx);
835 }
836
837 static const struct fs_context_operations erofs_context_ops = {
838 .parse_param = erofs_fc_parse_param,
839 .get_tree = erofs_fc_get_tree,
840 .reconfigure = erofs_fc_reconfigure,
841 .free = erofs_fc_free,
842 };
843
844 static const struct fs_context_operations erofs_anon_context_ops = {
845 .get_tree = erofs_fc_anon_get_tree,
846 };
847
erofs_init_fs_context(struct fs_context * fc)848 static int erofs_init_fs_context(struct fs_context *fc)
849 {
850 struct erofs_fs_context *ctx;
851
852 /* pseudo mount for anon inodes */
853 if (fc->sb_flags & SB_KERNMOUNT) {
854 fc->ops = &erofs_anon_context_ops;
855 return 0;
856 }
857
858 ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
859 if (!ctx)
860 return -ENOMEM;
861 ctx->devs = kzalloc(sizeof(struct erofs_dev_context), GFP_KERNEL);
862 if (!ctx->devs) {
863 kfree(ctx);
864 return -ENOMEM;
865 }
866 fc->fs_private = ctx;
867
868 idr_init(&ctx->devs->tree);
869 init_rwsem(&ctx->devs->rwsem);
870 erofs_default_options(ctx);
871 fc->ops = &erofs_context_ops;
872 return 0;
873 }
874
erofs_kill_sb(struct super_block * sb)875 static void erofs_kill_sb(struct super_block *sb)
876 {
877 struct erofs_sb_info *sbi;
878
879 /* pseudo mount for anon inodes */
880 if (sb->s_flags & SB_KERNMOUNT) {
881 kill_anon_super(sb);
882 return;
883 }
884
885 if (erofs_is_fscache_mode(sb))
886 kill_anon_super(sb);
887 else
888 kill_block_super(sb);
889
890 sbi = EROFS_SB(sb);
891 if (!sbi)
892 return;
893
894 erofs_free_dev_context(sbi->devs);
895 fs_put_dax(sbi->dax_dev, NULL);
896 erofs_fscache_unregister_fs(sb);
897 kfree(sbi->fsid);
898 kfree(sbi->domain_id);
899 kfree(sbi);
900 sb->s_fs_info = NULL;
901 }
902
erofs_put_super(struct super_block * sb)903 static void erofs_put_super(struct super_block *sb)
904 {
905 struct erofs_sb_info *const sbi = EROFS_SB(sb);
906
907 DBG_BUGON(!sbi);
908
909 erofs_unregister_sysfs(sb);
910 erofs_shrinker_unregister(sb);
911 erofs_xattr_prefixes_cleanup(sb);
912 #ifdef CONFIG_EROFS_FS_ZIP
913 iput(sbi->managed_cache);
914 sbi->managed_cache = NULL;
915 #endif
916 iput(sbi->packed_inode);
917 sbi->packed_inode = NULL;
918 erofs_free_dev_context(sbi->devs);
919 sbi->devs = NULL;
920 erofs_fscache_unregister_fs(sb);
921 }
922
923 struct file_system_type erofs_fs_type = {
924 .owner = THIS_MODULE,
925 .name = "erofs",
926 .init_fs_context = erofs_init_fs_context,
927 .kill_sb = erofs_kill_sb,
928 .fs_flags = FS_REQUIRES_DEV | FS_ALLOW_IDMAP,
929 };
930 MODULE_ALIAS_FS("erofs");
931
erofs_module_init(void)932 static int __init erofs_module_init(void)
933 {
934 int err;
935
936 erofs_check_ondisk_layout_definitions();
937
938 erofs_inode_cachep = kmem_cache_create("erofs_inode",
939 sizeof(struct erofs_inode), 0,
940 SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD | SLAB_ACCOUNT,
941 erofs_inode_init_once);
942 if (!erofs_inode_cachep)
943 return -ENOMEM;
944
945 err = erofs_init_shrinker();
946 if (err)
947 goto shrinker_err;
948
949 err = z_erofs_lzma_init();
950 if (err)
951 goto lzma_err;
952
953 err = z_erofs_deflate_init();
954 if (err)
955 goto deflate_err;
956
957 erofs_pcpubuf_init();
958 err = z_erofs_init_zip_subsystem();
959 if (err)
960 goto zip_err;
961
962 err = erofs_init_sysfs();
963 if (err)
964 goto sysfs_err;
965
966 err = register_filesystem(&erofs_fs_type);
967 if (err)
968 goto fs_err;
969
970 return 0;
971
972 fs_err:
973 erofs_exit_sysfs();
974 sysfs_err:
975 z_erofs_exit_zip_subsystem();
976 zip_err:
977 z_erofs_deflate_exit();
978 deflate_err:
979 z_erofs_lzma_exit();
980 lzma_err:
981 erofs_exit_shrinker();
982 shrinker_err:
983 kmem_cache_destroy(erofs_inode_cachep);
984 return err;
985 }
986
erofs_module_exit(void)987 static void __exit erofs_module_exit(void)
988 {
989 unregister_filesystem(&erofs_fs_type);
990
991 /* Ensure all RCU free inodes / pclusters are safe to be destroyed. */
992 rcu_barrier();
993
994 erofs_exit_sysfs();
995 z_erofs_exit_zip_subsystem();
996 z_erofs_deflate_exit();
997 z_erofs_lzma_exit();
998 erofs_exit_shrinker();
999 kmem_cache_destroy(erofs_inode_cachep);
1000 erofs_pcpubuf_exit();
1001 }
1002
erofs_statfs(struct dentry * dentry,struct kstatfs * buf)1003 static int erofs_statfs(struct dentry *dentry, struct kstatfs *buf)
1004 {
1005 struct super_block *sb = dentry->d_sb;
1006 struct erofs_sb_info *sbi = EROFS_SB(sb);
1007 u64 id = 0;
1008
1009 if (!erofs_is_fscache_mode(sb))
1010 id = huge_encode_dev(sb->s_bdev->bd_dev);
1011
1012 buf->f_type = sb->s_magic;
1013 buf->f_bsize = sb->s_blocksize;
1014 buf->f_blocks = sbi->total_blocks;
1015 buf->f_bfree = buf->f_bavail = 0;
1016
1017 buf->f_files = ULLONG_MAX;
1018 buf->f_ffree = ULLONG_MAX - sbi->inos;
1019
1020 buf->f_namelen = EROFS_NAME_LEN;
1021
1022 buf->f_fsid = u64_to_fsid(id);
1023 return 0;
1024 }
1025
erofs_show_options(struct seq_file * seq,struct dentry * root)1026 static int erofs_show_options(struct seq_file *seq, struct dentry *root)
1027 {
1028 struct erofs_sb_info *sbi = EROFS_SB(root->d_sb);
1029 struct erofs_mount_opts *opt = &sbi->opt;
1030
1031 #ifdef CONFIG_EROFS_FS_XATTR
1032 if (test_opt(opt, XATTR_USER))
1033 seq_puts(seq, ",user_xattr");
1034 else
1035 seq_puts(seq, ",nouser_xattr");
1036 #endif
1037 #ifdef CONFIG_EROFS_FS_POSIX_ACL
1038 if (test_opt(opt, POSIX_ACL))
1039 seq_puts(seq, ",acl");
1040 else
1041 seq_puts(seq, ",noacl");
1042 #endif
1043 #ifdef CONFIG_EROFS_FS_ZIP
1044 if (opt->cache_strategy == EROFS_ZIP_CACHE_DISABLED)
1045 seq_puts(seq, ",cache_strategy=disabled");
1046 else if (opt->cache_strategy == EROFS_ZIP_CACHE_READAHEAD)
1047 seq_puts(seq, ",cache_strategy=readahead");
1048 else if (opt->cache_strategy == EROFS_ZIP_CACHE_READAROUND)
1049 seq_puts(seq, ",cache_strategy=readaround");
1050 #endif
1051 if (test_opt(opt, DAX_ALWAYS))
1052 seq_puts(seq, ",dax=always");
1053 if (test_opt(opt, DAX_NEVER))
1054 seq_puts(seq, ",dax=never");
1055 #ifdef CONFIG_EROFS_FS_ONDEMAND
1056 if (sbi->fsid)
1057 seq_printf(seq, ",fsid=%s", sbi->fsid);
1058 if (sbi->domain_id)
1059 seq_printf(seq, ",domain_id=%s", sbi->domain_id);
1060 #endif
1061 return 0;
1062 }
1063
1064 const struct super_operations erofs_sops = {
1065 .put_super = erofs_put_super,
1066 .alloc_inode = erofs_alloc_inode,
1067 .free_inode = erofs_free_inode,
1068 .statfs = erofs_statfs,
1069 .show_options = erofs_show_options,
1070 };
1071
1072 module_init(erofs_module_init);
1073 module_exit(erofs_module_exit);
1074
1075 MODULE_DESCRIPTION("Enhanced ROM File System");
1076 MODULE_AUTHOR("Gao Xiang, Chao Yu, Miao Xie, CONSUMER BG, HUAWEI Inc.");
1077 MODULE_LICENSE("GPL");
1078
