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/statfs.h>
8 #include <linux/seq_file.h>
9 #include <linux/crc32c.h>
10 #include <linux/fs_context.h>
11 #include <linux/fs_parser.h>
12 #include <linux/exportfs.h>
13 #include <linux/backing-dev.h>
14 #include "xattr.h"
15
16 #define CREATE_TRACE_POINTS
17 #include <trace/events/erofs.h>
18
19 static struct kmem_cache *erofs_inode_cachep __read_mostly;
20
_erofs_printk(struct super_block * sb,const char * fmt,...)21 void _erofs_printk(struct super_block *sb, const char *fmt, ...)
22 {
23 struct va_format vaf;
24 va_list args;
25 int level;
26
27 va_start(args, fmt);
28
29 level = printk_get_level(fmt);
30 vaf.fmt = printk_skip_level(fmt);
31 vaf.va = &args;
32 if (sb)
33 printk("%c%cerofs (device %s): %pV",
34 KERN_SOH_ASCII, level, sb->s_id, &vaf);
35 else
36 printk("%c%cerofs: %pV", KERN_SOH_ASCII, level, &vaf);
37 va_end(args);
38 }
39
erofs_superblock_csum_verify(struct super_block * sb,void * sbdata)40 static int erofs_superblock_csum_verify(struct super_block *sb, void *sbdata)
41 {
42 struct erofs_super_block *dsb = sbdata + EROFS_SUPER_OFFSET;
43 u32 len = 1 << EROFS_SB(sb)->blkszbits, crc;
44
45 if (len > EROFS_SUPER_OFFSET)
46 len -= EROFS_SUPER_OFFSET;
47 len -= offsetof(struct erofs_super_block, checksum) +
48 sizeof(dsb->checksum);
49
50 /* skip .magic(pre-verified) and .checksum(0) fields */
51 crc = crc32c(0x5045B54A, (&dsb->checksum) + 1, len);
52 if (crc == le32_to_cpu(dsb->checksum))
53 return 0;
54 erofs_err(sb, "invalid checksum 0x%08x, 0x%08x expected",
55 crc, le32_to_cpu(dsb->checksum));
56 return -EBADMSG;
57 }
58
erofs_inode_init_once(void * ptr)59 static void erofs_inode_init_once(void *ptr)
60 {
61 struct erofs_inode *vi = ptr;
62
63 inode_init_once(&vi->vfs_inode);
64 }
65
erofs_alloc_inode(struct super_block * sb)66 static struct inode *erofs_alloc_inode(struct super_block *sb)
67 {
68 struct erofs_inode *vi =
69 alloc_inode_sb(sb, erofs_inode_cachep, GFP_KERNEL);
70
71 if (!vi)
72 return NULL;
73
74 /* zero out everything except vfs_inode */
75 memset(vi, 0, offsetof(struct erofs_inode, vfs_inode));
76 return &vi->vfs_inode;
77 }
78
erofs_free_inode(struct inode * inode)79 static void erofs_free_inode(struct inode *inode)
80 {
81 struct erofs_inode *vi = EROFS_I(inode);
82
83 if (inode->i_op == &erofs_fast_symlink_iops)
84 kfree(inode->i_link);
85 kfree(vi->xattr_shared_xattrs);
86 kmem_cache_free(erofs_inode_cachep, vi);
87 }
88
89 /* 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)90 void *erofs_read_metadata(struct super_block *sb, struct erofs_buf *buf,
91 erofs_off_t *offset, int *lengthp)
92 {
93 u8 *buffer, *ptr;
94 int len, i, cnt;
95
96 *offset = round_up(*offset, 4);
97 ptr = erofs_bread(buf, *offset, true);
98 if (IS_ERR(ptr))
99 return ptr;
100
101 len = le16_to_cpu(*(__le16 *)ptr);
102 if (!len)
103 len = U16_MAX + 1;
104 buffer = kmalloc(len, GFP_KERNEL);
105 if (!buffer)
106 return ERR_PTR(-ENOMEM);
107 *offset += sizeof(__le16);
108 *lengthp = len;
109
110 for (i = 0; i < len; i += cnt) {
111 cnt = min_t(int, sb->s_blocksize - erofs_blkoff(sb, *offset),
112 len - i);
113 ptr = erofs_bread(buf, *offset, true);
114 if (IS_ERR(ptr)) {
115 kfree(buffer);
116 return ptr;
117 }
118 memcpy(buffer + i, ptr, cnt);
119 *offset += cnt;
120 }
121 return buffer;
122 }
123
124 #ifndef CONFIG_EROFS_FS_ZIP
z_erofs_parse_cfgs(struct super_block * sb,struct erofs_super_block * dsb)125 static int z_erofs_parse_cfgs(struct super_block *sb,
126 struct erofs_super_block *dsb)
127 {
128 if (!dsb->u1.available_compr_algs)
129 return 0;
130
131 erofs_err(sb, "compression disabled, unable to mount compressed EROFS");
132 return -EOPNOTSUPP;
133 }
134 #endif
135
erofs_init_device(struct erofs_buf * buf,struct super_block * sb,struct erofs_device_info * dif,erofs_off_t * pos)136 static int erofs_init_device(struct erofs_buf *buf, struct super_block *sb,
137 struct erofs_device_info *dif, erofs_off_t *pos)
138 {
139 struct erofs_sb_info *sbi = EROFS_SB(sb);
140 struct erofs_fscache *fscache;
141 struct erofs_deviceslot *dis;
142 struct file *file;
143
144 dis = erofs_read_metabuf(buf, sb, *pos, false);
145 if (IS_ERR(dis))
146 return PTR_ERR(dis);
147
148 if (!sbi->devs->flatdev && !dif->path) {
149 if (!dis->tag[0]) {
150 erofs_err(sb, "empty device tag @ pos %llu", *pos);
151 return -EINVAL;
152 }
153 dif->path = kmemdup_nul(dis->tag, sizeof(dis->tag), GFP_KERNEL);
154 if (!dif->path)
155 return -ENOMEM;
156 }
157
158 if (erofs_is_fscache_mode(sb)) {
159 fscache = erofs_fscache_register_cookie(sb, dif->path, 0);
160 if (IS_ERR(fscache))
161 return PTR_ERR(fscache);
162 dif->fscache = fscache;
163 } else if (!sbi->devs->flatdev) {
164 file = erofs_is_fileio_mode(sbi) ?
165 filp_open(dif->path, O_RDONLY | O_LARGEFILE, 0) :
166 bdev_file_open_by_path(dif->path,
167 BLK_OPEN_READ, sb->s_type, NULL);
168 if (IS_ERR(file)) {
169 if (file == ERR_PTR(-ENOTBLK))
170 return -EINVAL;
171 return PTR_ERR(file);
172 }
173
174 if (!erofs_is_fileio_mode(sbi)) {
175 dif->dax_dev = fs_dax_get_by_bdev(file_bdev(file),
176 &dif->dax_part_off, NULL, NULL);
177 } else if (!S_ISREG(file_inode(file)->i_mode)) {
178 fput(file);
179 return -EINVAL;
180 }
181 dif->file = file;
182 }
183
184 dif->blocks = le32_to_cpu(dis->blocks_lo);
185 dif->uniaddr = le32_to_cpu(dis->uniaddr_lo);
186 sbi->total_blocks += dif->blocks;
187 *pos += EROFS_DEVT_SLOT_SIZE;
188 return 0;
189 }
190
erofs_scan_devices(struct super_block * sb,struct erofs_super_block * dsb)191 static int erofs_scan_devices(struct super_block *sb,
192 struct erofs_super_block *dsb)
193 {
194 struct erofs_sb_info *sbi = EROFS_SB(sb);
195 unsigned int ondisk_extradevs;
196 erofs_off_t pos;
197 struct erofs_buf buf = __EROFS_BUF_INITIALIZER;
198 struct erofs_device_info *dif;
199 int id, err = 0;
200
201 sbi->total_blocks = sbi->dif0.blocks;
202 if (!erofs_sb_has_device_table(sbi))
203 ondisk_extradevs = 0;
204 else
205 ondisk_extradevs = le16_to_cpu(dsb->extra_devices);
206
207 if (sbi->devs->extra_devices &&
208 ondisk_extradevs != sbi->devs->extra_devices) {
209 erofs_err(sb, "extra devices don't match (ondisk %u, given %u)",
210 ondisk_extradevs, sbi->devs->extra_devices);
211 return -EINVAL;
212 }
213 if (!ondisk_extradevs)
214 return 0;
215
216 if (!sbi->devs->extra_devices && !erofs_is_fscache_mode(sb))
217 sbi->devs->flatdev = true;
218
219 sbi->device_id_mask = roundup_pow_of_two(ondisk_extradevs + 1) - 1;
220 pos = le16_to_cpu(dsb->devt_slotoff) * EROFS_DEVT_SLOT_SIZE;
221 down_read(&sbi->devs->rwsem);
222 if (sbi->devs->extra_devices) {
223 idr_for_each_entry(&sbi->devs->tree, dif, id) {
224 err = erofs_init_device(&buf, sb, dif, &pos);
225 if (err)
226 break;
227 }
228 } else {
229 for (id = 0; id < ondisk_extradevs; id++) {
230 dif = kzalloc(sizeof(*dif), GFP_KERNEL);
231 if (!dif) {
232 err = -ENOMEM;
233 break;
234 }
235
236 err = idr_alloc(&sbi->devs->tree, dif, 0, 0, GFP_KERNEL);
237 if (err < 0) {
238 kfree(dif);
239 break;
240 }
241 ++sbi->devs->extra_devices;
242
243 err = erofs_init_device(&buf, sb, dif, &pos);
244 if (err)
245 break;
246 }
247 }
248 up_read(&sbi->devs->rwsem);
249 erofs_put_metabuf(&buf);
250 return err;
251 }
252
erofs_read_superblock(struct super_block * sb)253 static int erofs_read_superblock(struct super_block *sb)
254 {
255 struct erofs_sb_info *sbi = EROFS_SB(sb);
256 struct erofs_buf buf = __EROFS_BUF_INITIALIZER;
257 struct erofs_super_block *dsb;
258 void *data;
259 int ret;
260
261 data = erofs_read_metabuf(&buf, sb, 0, false);
262 if (IS_ERR(data)) {
263 erofs_err(sb, "cannot read erofs superblock");
264 return PTR_ERR(data);
265 }
266
267 dsb = (struct erofs_super_block *)(data + EROFS_SUPER_OFFSET);
268 ret = -EINVAL;
269 if (le32_to_cpu(dsb->magic) != EROFS_SUPER_MAGIC_V1) {
270 erofs_err(sb, "cannot find valid erofs superblock");
271 goto out;
272 }
273
274 sbi->blkszbits = dsb->blkszbits;
275 if (sbi->blkszbits < 9 || sbi->blkszbits > PAGE_SHIFT) {
276 erofs_err(sb, "blkszbits %u isn't supported", sbi->blkszbits);
277 goto out;
278 }
279 if (dsb->dirblkbits) {
280 erofs_err(sb, "dirblkbits %u isn't supported", dsb->dirblkbits);
281 goto out;
282 }
283
284 sbi->feature_compat = le32_to_cpu(dsb->feature_compat);
285 if (erofs_sb_has_sb_chksum(sbi)) {
286 ret = erofs_superblock_csum_verify(sb, data);
287 if (ret)
288 goto out;
289 }
290
291 ret = -EINVAL;
292 sbi->feature_incompat = le32_to_cpu(dsb->feature_incompat);
293 if (sbi->feature_incompat & ~EROFS_ALL_FEATURE_INCOMPAT) {
294 erofs_err(sb, "unidentified incompatible feature %x, please upgrade kernel",
295 sbi->feature_incompat & ~EROFS_ALL_FEATURE_INCOMPAT);
296 goto out;
297 }
298
299 sbi->sb_size = 128 + dsb->sb_extslots * EROFS_SB_EXTSLOT_SIZE;
300 if (sbi->sb_size > PAGE_SIZE - EROFS_SUPER_OFFSET) {
301 erofs_err(sb, "invalid sb_extslots %u (more than a fs block)",
302 sbi->sb_size);
303 goto out;
304 }
305 sbi->dif0.blocks = le32_to_cpu(dsb->blocks_lo);
306 sbi->meta_blkaddr = le32_to_cpu(dsb->meta_blkaddr);
307 #ifdef CONFIG_EROFS_FS_XATTR
308 sbi->xattr_blkaddr = le32_to_cpu(dsb->xattr_blkaddr);
309 sbi->xattr_prefix_start = le32_to_cpu(dsb->xattr_prefix_start);
310 sbi->xattr_prefix_count = dsb->xattr_prefix_count;
311 sbi->xattr_filter_reserved = dsb->xattr_filter_reserved;
312 #endif
313 sbi->islotbits = ilog2(sizeof(struct erofs_inode_compact));
314 if (erofs_sb_has_48bit(sbi) && dsb->rootnid_8b) {
315 sbi->root_nid = le64_to_cpu(dsb->rootnid_8b);
316 sbi->dif0.blocks = (sbi->dif0.blocks << 32) |
317 le16_to_cpu(dsb->rb.blocks_hi);
318 } else {
319 sbi->root_nid = le16_to_cpu(dsb->rb.rootnid_2b);
320 }
321 sbi->packed_nid = le64_to_cpu(dsb->packed_nid);
322 if (erofs_sb_has_metabox(sbi)) {
323 if (sbi->sb_size <= offsetof(struct erofs_super_block,
324 metabox_nid))
325 return -EFSCORRUPTED;
326 sbi->metabox_nid = le64_to_cpu(dsb->metabox_nid);
327 if (sbi->metabox_nid & BIT_ULL(EROFS_DIRENT_NID_METABOX_BIT))
328 return -EFSCORRUPTED; /* self-loop detection */
329 }
330 sbi->inos = le64_to_cpu(dsb->inos);
331
332 sbi->epoch = (s64)le64_to_cpu(dsb->epoch);
333 sbi->fixed_nsec = le32_to_cpu(dsb->fixed_nsec);
334 super_set_uuid(sb, (void *)dsb->uuid, sizeof(dsb->uuid));
335
336 /* parse on-disk compression configurations */
337 ret = z_erofs_parse_cfgs(sb, dsb);
338 if (ret < 0)
339 goto out;
340
341 /* handle multiple devices */
342 ret = erofs_scan_devices(sb, dsb);
343
344 if (erofs_sb_has_48bit(sbi))
345 erofs_info(sb, "EXPERIMENTAL 48-bit layout support in use. Use at your own risk!");
346 if (erofs_sb_has_metabox(sbi))
347 erofs_info(sb, "EXPERIMENTAL metadata compression support in use. Use at your own risk!");
348 if (erofs_is_fscache_mode(sb))
349 erofs_info(sb, "[deprecated] fscache-based on-demand read feature in use. Use at your own risk!");
350 out:
351 erofs_put_metabuf(&buf);
352 return ret;
353 }
354
erofs_default_options(struct erofs_sb_info * sbi)355 static void erofs_default_options(struct erofs_sb_info *sbi)
356 {
357 #ifdef CONFIG_EROFS_FS_ZIP
358 sbi->opt.cache_strategy = EROFS_ZIP_CACHE_READAROUND;
359 sbi->opt.max_sync_decompress_pages = 3;
360 sbi->opt.sync_decompress = EROFS_SYNC_DECOMPRESS_AUTO;
361 #endif
362 #ifdef CONFIG_EROFS_FS_XATTR
363 set_opt(&sbi->opt, XATTR_USER);
364 #endif
365 #ifdef CONFIG_EROFS_FS_POSIX_ACL
366 set_opt(&sbi->opt, POSIX_ACL);
367 #endif
368 }
369
370 enum {
371 Opt_user_xattr, Opt_acl, Opt_cache_strategy, Opt_dax, Opt_dax_enum,
372 Opt_device, Opt_fsid, Opt_domain_id, Opt_directio, Opt_fsoffset,
373 };
374
375 static const struct constant_table erofs_param_cache_strategy[] = {
376 {"disabled", EROFS_ZIP_CACHE_DISABLED},
377 {"readahead", EROFS_ZIP_CACHE_READAHEAD},
378 {"readaround", EROFS_ZIP_CACHE_READAROUND},
379 {}
380 };
381
382 static const struct constant_table erofs_dax_param_enums[] = {
383 {"always", EROFS_MOUNT_DAX_ALWAYS},
384 {"never", EROFS_MOUNT_DAX_NEVER},
385 {}
386 };
387
388 static const struct fs_parameter_spec erofs_fs_parameters[] = {
389 fsparam_flag_no("user_xattr", Opt_user_xattr),
390 fsparam_flag_no("acl", Opt_acl),
391 fsparam_enum("cache_strategy", Opt_cache_strategy,
392 erofs_param_cache_strategy),
393 fsparam_flag("dax", Opt_dax),
394 fsparam_enum("dax", Opt_dax_enum, erofs_dax_param_enums),
395 fsparam_string("device", Opt_device),
396 fsparam_string("fsid", Opt_fsid),
397 fsparam_string("domain_id", Opt_domain_id),
398 fsparam_flag_no("directio", Opt_directio),
399 fsparam_u64("fsoffset", Opt_fsoffset),
400 {}
401 };
402
erofs_fc_set_dax_mode(struct fs_context * fc,unsigned int mode)403 static bool erofs_fc_set_dax_mode(struct fs_context *fc, unsigned int mode)
404 {
405 #ifdef CONFIG_FS_DAX
406 struct erofs_sb_info *sbi = fc->s_fs_info;
407
408 switch (mode) {
409 case EROFS_MOUNT_DAX_ALWAYS:
410 set_opt(&sbi->opt, DAX_ALWAYS);
411 clear_opt(&sbi->opt, DAX_NEVER);
412 return true;
413 case EROFS_MOUNT_DAX_NEVER:
414 set_opt(&sbi->opt, DAX_NEVER);
415 clear_opt(&sbi->opt, DAX_ALWAYS);
416 return true;
417 default:
418 DBG_BUGON(1);
419 return false;
420 }
421 #else
422 errorfc(fc, "dax options not supported");
423 return false;
424 #endif
425 }
426
erofs_fc_parse_param(struct fs_context * fc,struct fs_parameter * param)427 static int erofs_fc_parse_param(struct fs_context *fc,
428 struct fs_parameter *param)
429 {
430 struct erofs_sb_info *sbi = fc->s_fs_info;
431 struct fs_parse_result result;
432 struct erofs_device_info *dif;
433 int opt, ret;
434
435 opt = fs_parse(fc, erofs_fs_parameters, param, &result);
436 if (opt < 0)
437 return opt;
438
439 switch (opt) {
440 case Opt_user_xattr:
441 #ifdef CONFIG_EROFS_FS_XATTR
442 if (result.boolean)
443 set_opt(&sbi->opt, XATTR_USER);
444 else
445 clear_opt(&sbi->opt, XATTR_USER);
446 #else
447 errorfc(fc, "{,no}user_xattr options not supported");
448 #endif
449 break;
450 case Opt_acl:
451 #ifdef CONFIG_EROFS_FS_POSIX_ACL
452 if (result.boolean)
453 set_opt(&sbi->opt, POSIX_ACL);
454 else
455 clear_opt(&sbi->opt, POSIX_ACL);
456 #else
457 errorfc(fc, "{,no}acl options not supported");
458 #endif
459 break;
460 case Opt_cache_strategy:
461 #ifdef CONFIG_EROFS_FS_ZIP
462 sbi->opt.cache_strategy = result.uint_32;
463 #else
464 errorfc(fc, "compression not supported, cache_strategy ignored");
465 #endif
466 break;
467 case Opt_dax:
468 if (!erofs_fc_set_dax_mode(fc, EROFS_MOUNT_DAX_ALWAYS))
469 return -EINVAL;
470 break;
471 case Opt_dax_enum:
472 if (!erofs_fc_set_dax_mode(fc, result.uint_32))
473 return -EINVAL;
474 break;
475 case Opt_device:
476 dif = kzalloc(sizeof(*dif), GFP_KERNEL);
477 if (!dif)
478 return -ENOMEM;
479 dif->path = kstrdup(param->string, GFP_KERNEL);
480 if (!dif->path) {
481 kfree(dif);
482 return -ENOMEM;
483 }
484 down_write(&sbi->devs->rwsem);
485 ret = idr_alloc(&sbi->devs->tree, dif, 0, 0, GFP_KERNEL);
486 up_write(&sbi->devs->rwsem);
487 if (ret < 0) {
488 kfree(dif->path);
489 kfree(dif);
490 return ret;
491 }
492 ++sbi->devs->extra_devices;
493 break;
494 #ifdef CONFIG_EROFS_FS_ONDEMAND
495 case Opt_fsid:
496 kfree(sbi->fsid);
497 sbi->fsid = kstrdup(param->string, GFP_KERNEL);
498 if (!sbi->fsid)
499 return -ENOMEM;
500 break;
501 case Opt_domain_id:
502 kfree(sbi->domain_id);
503 sbi->domain_id = kstrdup(param->string, GFP_KERNEL);
504 if (!sbi->domain_id)
505 return -ENOMEM;
506 break;
507 #else
508 case Opt_fsid:
509 case Opt_domain_id:
510 errorfc(fc, "%s option not supported", erofs_fs_parameters[opt].name);
511 break;
512 #endif
513 case Opt_directio:
514 #ifdef CONFIG_EROFS_FS_BACKED_BY_FILE
515 if (result.boolean)
516 set_opt(&sbi->opt, DIRECT_IO);
517 else
518 clear_opt(&sbi->opt, DIRECT_IO);
519 #else
520 errorfc(fc, "%s option not supported", erofs_fs_parameters[opt].name);
521 #endif
522 break;
523 case Opt_fsoffset:
524 sbi->dif0.fsoff = result.uint_64;
525 break;
526 }
527 return 0;
528 }
529
erofs_encode_fh(struct inode * inode,u32 * fh,int * max_len,struct inode * parent)530 static int erofs_encode_fh(struct inode *inode, u32 *fh, int *max_len,
531 struct inode *parent)
532 {
533 erofs_nid_t nid = EROFS_I(inode)->nid;
534 int len = parent ? 6 : 3;
535
536 if (*max_len < len) {
537 *max_len = len;
538 return FILEID_INVALID;
539 }
540
541 fh[0] = (u32)(nid >> 32);
542 fh[1] = (u32)(nid & 0xffffffff);
543 fh[2] = inode->i_generation;
544
545 if (parent) {
546 nid = EROFS_I(parent)->nid;
547
548 fh[3] = (u32)(nid >> 32);
549 fh[4] = (u32)(nid & 0xffffffff);
550 fh[5] = parent->i_generation;
551 }
552
553 *max_len = len;
554 return parent ? FILEID_INO64_GEN_PARENT : FILEID_INO64_GEN;
555 }
556
erofs_fh_to_dentry(struct super_block * sb,struct fid * fid,int fh_len,int fh_type)557 static struct dentry *erofs_fh_to_dentry(struct super_block *sb,
558 struct fid *fid, int fh_len, int fh_type)
559 {
560 if ((fh_type != FILEID_INO64_GEN &&
561 fh_type != FILEID_INO64_GEN_PARENT) || fh_len < 3)
562 return NULL;
563
564 return d_obtain_alias(erofs_iget(sb,
565 ((u64)fid->raw[0] << 32) | fid->raw[1]));
566 }
567
erofs_fh_to_parent(struct super_block * sb,struct fid * fid,int fh_len,int fh_type)568 static struct dentry *erofs_fh_to_parent(struct super_block *sb,
569 struct fid *fid, int fh_len, int fh_type)
570 {
571 if (fh_type != FILEID_INO64_GEN_PARENT || fh_len < 6)
572 return NULL;
573
574 return d_obtain_alias(erofs_iget(sb,
575 ((u64)fid->raw[3] << 32) | fid->raw[4]));
576 }
577
erofs_get_parent(struct dentry * child)578 static struct dentry *erofs_get_parent(struct dentry *child)
579 {
580 erofs_nid_t nid;
581 unsigned int d_type;
582 int err;
583
584 err = erofs_namei(d_inode(child), &dotdot_name, &nid, &d_type);
585 if (err)
586 return ERR_PTR(err);
587 return d_obtain_alias(erofs_iget(child->d_sb, nid));
588 }
589
590 static const struct export_operations erofs_export_ops = {
591 .encode_fh = erofs_encode_fh,
592 .fh_to_dentry = erofs_fh_to_dentry,
593 .fh_to_parent = erofs_fh_to_parent,
594 .get_parent = erofs_get_parent,
595 };
596
erofs_set_sysfs_name(struct super_block * sb)597 static void erofs_set_sysfs_name(struct super_block *sb)
598 {
599 struct erofs_sb_info *sbi = EROFS_SB(sb);
600
601 if (sbi->domain_id)
602 super_set_sysfs_name_generic(sb, "%s,%s", sbi->domain_id,
603 sbi->fsid);
604 else if (sbi->fsid)
605 super_set_sysfs_name_generic(sb, "%s", sbi->fsid);
606 else if (erofs_is_fileio_mode(sbi))
607 super_set_sysfs_name_generic(sb, "%s",
608 bdi_dev_name(sb->s_bdi));
609 else
610 super_set_sysfs_name_id(sb);
611 }
612
erofs_fc_fill_super(struct super_block * sb,struct fs_context * fc)613 static int erofs_fc_fill_super(struct super_block *sb, struct fs_context *fc)
614 {
615 struct inode *inode;
616 struct erofs_sb_info *sbi = EROFS_SB(sb);
617 int err;
618
619 sb->s_magic = EROFS_SUPER_MAGIC;
620 sb->s_flags |= SB_RDONLY | SB_NOATIME;
621 sb->s_maxbytes = MAX_LFS_FILESIZE;
622 sb->s_op = &erofs_sops;
623
624 sbi->blkszbits = PAGE_SHIFT;
625 if (!sb->s_bdev) {
626 sb->s_blocksize = PAGE_SIZE;
627 sb->s_blocksize_bits = PAGE_SHIFT;
628
629 if (erofs_is_fscache_mode(sb)) {
630 err = erofs_fscache_register_fs(sb);
631 if (err)
632 return err;
633 }
634 err = super_setup_bdi(sb);
635 if (err)
636 return err;
637 } else {
638 if (!sb_set_blocksize(sb, PAGE_SIZE)) {
639 errorfc(fc, "failed to set initial blksize");
640 return -EINVAL;
641 }
642
643 sbi->dif0.dax_dev = fs_dax_get_by_bdev(sb->s_bdev,
644 &sbi->dif0.dax_part_off, NULL, NULL);
645 }
646
647 err = erofs_read_superblock(sb);
648 if (err)
649 return err;
650
651 if (sb->s_blocksize_bits != sbi->blkszbits) {
652 if (erofs_is_fscache_mode(sb)) {
653 errorfc(fc, "unsupported blksize for fscache mode");
654 return -EINVAL;
655 }
656
657 if (erofs_is_fileio_mode(sbi)) {
658 sb->s_blocksize = 1 << sbi->blkszbits;
659 sb->s_blocksize_bits = sbi->blkszbits;
660 } else if (!sb_set_blocksize(sb, 1 << sbi->blkszbits)) {
661 errorfc(fc, "failed to set erofs blksize");
662 return -EINVAL;
663 }
664 }
665
666 if (sbi->dif0.fsoff) {
667 if (sbi->dif0.fsoff & (sb->s_blocksize - 1))
668 return invalfc(fc, "fsoffset %llu is not aligned to block size %lu",
669 sbi->dif0.fsoff, sb->s_blocksize);
670 if (erofs_is_fscache_mode(sb))
671 return invalfc(fc, "cannot use fsoffset in fscache mode");
672 }
673
674 if (test_opt(&sbi->opt, DAX_ALWAYS)) {
675 if (!sbi->dif0.dax_dev) {
676 errorfc(fc, "DAX unsupported by block device. Turning off DAX.");
677 clear_opt(&sbi->opt, DAX_ALWAYS);
678 } else if (sbi->blkszbits != PAGE_SHIFT) {
679 errorfc(fc, "unsupported blocksize for DAX");
680 clear_opt(&sbi->opt, DAX_ALWAYS);
681 }
682 }
683
684 sb->s_time_gran = 1;
685 sb->s_xattr = erofs_xattr_handlers;
686 sb->s_export_op = &erofs_export_ops;
687
688 if (test_opt(&sbi->opt, POSIX_ACL))
689 sb->s_flags |= SB_POSIXACL;
690 else
691 sb->s_flags &= ~SB_POSIXACL;
692
693 err = z_erofs_init_super(sb);
694 if (err)
695 return err;
696
697 if (erofs_sb_has_fragments(sbi) && sbi->packed_nid) {
698 inode = erofs_iget(sb, sbi->packed_nid);
699 if (IS_ERR(inode))
700 return PTR_ERR(inode);
701 sbi->packed_inode = inode;
702 }
703 if (erofs_sb_has_metabox(sbi)) {
704 inode = erofs_iget(sb, sbi->metabox_nid);
705 if (IS_ERR(inode))
706 return PTR_ERR(inode);
707 sbi->metabox_inode = inode;
708 }
709
710 inode = erofs_iget(sb, sbi->root_nid);
711 if (IS_ERR(inode))
712 return PTR_ERR(inode);
713
714 if (!S_ISDIR(inode->i_mode)) {
715 erofs_err(sb, "rootino(nid %llu) is not a directory(i_mode %o)",
716 sbi->root_nid, inode->i_mode);
717 iput(inode);
718 return -EINVAL;
719 }
720 sb->s_root = d_make_root(inode);
721 if (!sb->s_root)
722 return -ENOMEM;
723
724 erofs_shrinker_register(sb);
725 err = erofs_xattr_prefixes_init(sb);
726 if (err)
727 return err;
728
729 erofs_set_sysfs_name(sb);
730 err = erofs_register_sysfs(sb);
731 if (err)
732 return err;
733
734 sbi->dir_ra_bytes = EROFS_DIR_RA_BYTES;
735 erofs_info(sb, "mounted with root inode @ nid %llu.", sbi->root_nid);
736 return 0;
737 }
738
erofs_fc_get_tree(struct fs_context * fc)739 static int erofs_fc_get_tree(struct fs_context *fc)
740 {
741 struct erofs_sb_info *sbi = fc->s_fs_info;
742 int ret;
743
744 if (IS_ENABLED(CONFIG_EROFS_FS_ONDEMAND) && sbi->fsid)
745 return get_tree_nodev(fc, erofs_fc_fill_super);
746
747 ret = get_tree_bdev_flags(fc, erofs_fc_fill_super,
748 IS_ENABLED(CONFIG_EROFS_FS_BACKED_BY_FILE) ?
749 GET_TREE_BDEV_QUIET_LOOKUP : 0);
750 #ifdef CONFIG_EROFS_FS_BACKED_BY_FILE
751 if (ret == -ENOTBLK) {
752 struct file *file;
753
754 if (!fc->source)
755 return invalf(fc, "No source specified");
756 file = filp_open(fc->source, O_RDONLY | O_LARGEFILE, 0);
757 if (IS_ERR(file))
758 return PTR_ERR(file);
759 sbi->dif0.file = file;
760
761 if (S_ISREG(file_inode(sbi->dif0.file)->i_mode) &&
762 sbi->dif0.file->f_mapping->a_ops->read_folio)
763 return get_tree_nodev(fc, erofs_fc_fill_super);
764 }
765 #endif
766 return ret;
767 }
768
erofs_fc_reconfigure(struct fs_context * fc)769 static int erofs_fc_reconfigure(struct fs_context *fc)
770 {
771 struct super_block *sb = fc->root->d_sb;
772 struct erofs_sb_info *sbi = EROFS_SB(sb);
773 struct erofs_sb_info *new_sbi = fc->s_fs_info;
774
775 DBG_BUGON(!sb_rdonly(sb));
776
777 if (new_sbi->fsid || new_sbi->domain_id)
778 erofs_info(sb, "ignoring reconfiguration for fsid|domain_id.");
779
780 if (test_opt(&new_sbi->opt, POSIX_ACL))
781 fc->sb_flags |= SB_POSIXACL;
782 else
783 fc->sb_flags &= ~SB_POSIXACL;
784
785 sbi->opt = new_sbi->opt;
786
787 fc->sb_flags |= SB_RDONLY;
788 return 0;
789 }
790
erofs_release_device_info(int id,void * ptr,void * data)791 static int erofs_release_device_info(int id, void *ptr, void *data)
792 {
793 struct erofs_device_info *dif = ptr;
794
795 fs_put_dax(dif->dax_dev, NULL);
796 if (dif->file)
797 fput(dif->file);
798 erofs_fscache_unregister_cookie(dif->fscache);
799 dif->fscache = NULL;
800 kfree(dif->path);
801 kfree(dif);
802 return 0;
803 }
804
erofs_free_dev_context(struct erofs_dev_context * devs)805 static void erofs_free_dev_context(struct erofs_dev_context *devs)
806 {
807 if (!devs)
808 return;
809 idr_for_each(&devs->tree, &erofs_release_device_info, NULL);
810 idr_destroy(&devs->tree);
811 kfree(devs);
812 }
813
erofs_sb_free(struct erofs_sb_info * sbi)814 static void erofs_sb_free(struct erofs_sb_info *sbi)
815 {
816 erofs_free_dev_context(sbi->devs);
817 kfree(sbi->fsid);
818 kfree(sbi->domain_id);
819 if (sbi->dif0.file)
820 fput(sbi->dif0.file);
821 kfree(sbi);
822 }
823
erofs_fc_free(struct fs_context * fc)824 static void erofs_fc_free(struct fs_context *fc)
825 {
826 struct erofs_sb_info *sbi = fc->s_fs_info;
827
828 if (sbi) /* free here if an error occurs before transferring to sb */
829 erofs_sb_free(sbi);
830 }
831
832 static const struct fs_context_operations erofs_context_ops = {
833 .parse_param = erofs_fc_parse_param,
834 .get_tree = erofs_fc_get_tree,
835 .reconfigure = erofs_fc_reconfigure,
836 .free = erofs_fc_free,
837 };
838
erofs_init_fs_context(struct fs_context * fc)839 static int erofs_init_fs_context(struct fs_context *fc)
840 {
841 struct erofs_sb_info *sbi;
842
843 sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
844 if (!sbi)
845 return -ENOMEM;
846
847 sbi->devs = kzalloc(sizeof(struct erofs_dev_context), GFP_KERNEL);
848 if (!sbi->devs) {
849 kfree(sbi);
850 return -ENOMEM;
851 }
852 fc->s_fs_info = sbi;
853
854 idr_init(&sbi->devs->tree);
855 init_rwsem(&sbi->devs->rwsem);
856 erofs_default_options(sbi);
857 fc->ops = &erofs_context_ops;
858 return 0;
859 }
860
erofs_drop_internal_inodes(struct erofs_sb_info * sbi)861 static void erofs_drop_internal_inodes(struct erofs_sb_info *sbi)
862 {
863 iput(sbi->packed_inode);
864 sbi->packed_inode = NULL;
865 iput(sbi->metabox_inode);
866 sbi->metabox_inode = NULL;
867 #ifdef CONFIG_EROFS_FS_ZIP
868 iput(sbi->managed_cache);
869 sbi->managed_cache = NULL;
870 #endif
871 }
872
erofs_kill_sb(struct super_block * sb)873 static void erofs_kill_sb(struct super_block *sb)
874 {
875 struct erofs_sb_info *sbi = EROFS_SB(sb);
876
877 if ((IS_ENABLED(CONFIG_EROFS_FS_ONDEMAND) && sbi->fsid) ||
878 sbi->dif0.file)
879 kill_anon_super(sb);
880 else
881 kill_block_super(sb);
882 erofs_drop_internal_inodes(sbi);
883 fs_put_dax(sbi->dif0.dax_dev, NULL);
884 erofs_fscache_unregister_fs(sb);
885 erofs_sb_free(sbi);
886 sb->s_fs_info = NULL;
887 }
888
erofs_put_super(struct super_block * sb)889 static void erofs_put_super(struct super_block *sb)
890 {
891 struct erofs_sb_info *const sbi = EROFS_SB(sb);
892
893 erofs_unregister_sysfs(sb);
894 erofs_shrinker_unregister(sb);
895 erofs_xattr_prefixes_cleanup(sb);
896 erofs_drop_internal_inodes(sbi);
897 erofs_free_dev_context(sbi->devs);
898 sbi->devs = NULL;
899 erofs_fscache_unregister_fs(sb);
900 }
901
902 static struct file_system_type erofs_fs_type = {
903 .owner = THIS_MODULE,
904 .name = "erofs",
905 .init_fs_context = erofs_init_fs_context,
906 .kill_sb = erofs_kill_sb,
907 .fs_flags = FS_REQUIRES_DEV | FS_ALLOW_IDMAP,
908 };
909 MODULE_ALIAS_FS("erofs");
910
erofs_module_init(void)911 static int __init erofs_module_init(void)
912 {
913 int err;
914
915 erofs_check_ondisk_layout_definitions();
916
917 erofs_inode_cachep = kmem_cache_create("erofs_inode",
918 sizeof(struct erofs_inode), 0,
919 SLAB_RECLAIM_ACCOUNT | SLAB_ACCOUNT,
920 erofs_inode_init_once);
921 if (!erofs_inode_cachep)
922 return -ENOMEM;
923
924 err = erofs_init_shrinker();
925 if (err)
926 goto shrinker_err;
927
928 err = z_erofs_init_subsystem();
929 if (err)
930 goto zip_err;
931
932 err = erofs_init_sysfs();
933 if (err)
934 goto sysfs_err;
935
936 err = register_filesystem(&erofs_fs_type);
937 if (err)
938 goto fs_err;
939
940 return 0;
941
942 fs_err:
943 erofs_exit_sysfs();
944 sysfs_err:
945 z_erofs_exit_subsystem();
946 zip_err:
947 erofs_exit_shrinker();
948 shrinker_err:
949 kmem_cache_destroy(erofs_inode_cachep);
950 return err;
951 }
952
erofs_module_exit(void)953 static void __exit erofs_module_exit(void)
954 {
955 unregister_filesystem(&erofs_fs_type);
956
957 /* Ensure all RCU free inodes / pclusters are safe to be destroyed. */
958 rcu_barrier();
959
960 erofs_exit_sysfs();
961 z_erofs_exit_subsystem();
962 erofs_exit_shrinker();
963 kmem_cache_destroy(erofs_inode_cachep);
964 }
965
erofs_statfs(struct dentry * dentry,struct kstatfs * buf)966 static int erofs_statfs(struct dentry *dentry, struct kstatfs *buf)
967 {
968 struct super_block *sb = dentry->d_sb;
969 struct erofs_sb_info *sbi = EROFS_SB(sb);
970
971 buf->f_type = sb->s_magic;
972 buf->f_bsize = sb->s_blocksize;
973 buf->f_blocks = sbi->total_blocks;
974 buf->f_bfree = buf->f_bavail = 0;
975 buf->f_files = ULLONG_MAX;
976 buf->f_ffree = ULLONG_MAX - sbi->inos;
977 buf->f_namelen = EROFS_NAME_LEN;
978
979 if (uuid_is_null(&sb->s_uuid))
980 buf->f_fsid = u64_to_fsid(!sb->s_bdev ? 0 :
981 huge_encode_dev(sb->s_bdev->bd_dev));
982 else
983 buf->f_fsid = uuid_to_fsid(sb->s_uuid.b);
984 return 0;
985 }
986
erofs_show_options(struct seq_file * seq,struct dentry * root)987 static int erofs_show_options(struct seq_file *seq, struct dentry *root)
988 {
989 struct erofs_sb_info *sbi = EROFS_SB(root->d_sb);
990 struct erofs_mount_opts *opt = &sbi->opt;
991
992 if (IS_ENABLED(CONFIG_EROFS_FS_XATTR))
993 seq_puts(seq, test_opt(opt, XATTR_USER) ?
994 ",user_xattr" : ",nouser_xattr");
995 if (IS_ENABLED(CONFIG_EROFS_FS_POSIX_ACL))
996 seq_puts(seq, test_opt(opt, POSIX_ACL) ? ",acl" : ",noacl");
997 if (IS_ENABLED(CONFIG_EROFS_FS_ZIP))
998 seq_printf(seq, ",cache_strategy=%s",
999 erofs_param_cache_strategy[opt->cache_strategy].name);
1000 if (test_opt(opt, DAX_ALWAYS))
1001 seq_puts(seq, ",dax=always");
1002 if (test_opt(opt, DAX_NEVER))
1003 seq_puts(seq, ",dax=never");
1004 if (erofs_is_fileio_mode(sbi) && test_opt(opt, DIRECT_IO))
1005 seq_puts(seq, ",directio");
1006 #ifdef CONFIG_EROFS_FS_ONDEMAND
1007 if (sbi->fsid)
1008 seq_printf(seq, ",fsid=%s", sbi->fsid);
1009 if (sbi->domain_id)
1010 seq_printf(seq, ",domain_id=%s", sbi->domain_id);
1011 #endif
1012 if (sbi->dif0.fsoff)
1013 seq_printf(seq, ",fsoffset=%llu", sbi->dif0.fsoff);
1014 return 0;
1015 }
1016
1017 const struct super_operations erofs_sops = {
1018 .put_super = erofs_put_super,
1019 .alloc_inode = erofs_alloc_inode,
1020 .free_inode = erofs_free_inode,
1021 .statfs = erofs_statfs,
1022 .show_options = erofs_show_options,
1023 };
1024
1025 module_init(erofs_module_init);
1026 module_exit(erofs_module_exit);
1027
1028 MODULE_DESCRIPTION("Enhanced ROM File System");
1029 MODULE_AUTHOR("Gao Xiang, Chao Yu, Miao Xie, CONSUMER BG, HUAWEI Inc.");
1030 MODULE_LICENSE("GPL");
1031