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 if (!dif->dax_dev && test_opt(&sbi->opt, DAX_ALWAYS)) {
178 erofs_info(sb, "DAX unsupported by %s. Turning off DAX.",
179 dif->path);
180 clear_opt(&sbi->opt, DAX_ALWAYS);
181 }
182 } else if (!S_ISREG(file_inode(file)->i_mode)) {
183 fput(file);
184 return -EINVAL;
185 }
186 dif->file = file;
187 }
188
189 dif->blocks = le32_to_cpu(dis->blocks_lo);
190 dif->uniaddr = le32_to_cpu(dis->uniaddr_lo);
191 sbi->total_blocks += dif->blocks;
192 *pos += EROFS_DEVT_SLOT_SIZE;
193 return 0;
194 }
195
erofs_scan_devices(struct super_block * sb,struct erofs_super_block * dsb)196 static int erofs_scan_devices(struct super_block *sb,
197 struct erofs_super_block *dsb)
198 {
199 struct erofs_sb_info *sbi = EROFS_SB(sb);
200 unsigned int ondisk_extradevs;
201 erofs_off_t pos;
202 struct erofs_buf buf = __EROFS_BUF_INITIALIZER;
203 struct erofs_device_info *dif;
204 int id, err = 0;
205
206 sbi->total_blocks = sbi->dif0.blocks;
207 if (!erofs_sb_has_device_table(sbi))
208 ondisk_extradevs = 0;
209 else
210 ondisk_extradevs = le16_to_cpu(dsb->extra_devices);
211
212 if (sbi->devs->extra_devices &&
213 ondisk_extradevs != sbi->devs->extra_devices) {
214 erofs_err(sb, "extra devices don't match (ondisk %u, given %u)",
215 ondisk_extradevs, sbi->devs->extra_devices);
216 return -EINVAL;
217 }
218 if (!ondisk_extradevs) {
219 if (test_opt(&sbi->opt, DAX_ALWAYS) && !sbi->dif0.dax_dev) {
220 erofs_info(sb, "DAX unsupported by block device. Turning off DAX.");
221 clear_opt(&sbi->opt, DAX_ALWAYS);
222 }
223 return 0;
224 }
225
226 if (!sbi->devs->extra_devices && !erofs_is_fscache_mode(sb))
227 sbi->devs->flatdev = true;
228
229 sbi->device_id_mask = roundup_pow_of_two(ondisk_extradevs + 1) - 1;
230 pos = le16_to_cpu(dsb->devt_slotoff) * EROFS_DEVT_SLOT_SIZE;
231 down_read(&sbi->devs->rwsem);
232 if (sbi->devs->extra_devices) {
233 idr_for_each_entry(&sbi->devs->tree, dif, id) {
234 err = erofs_init_device(&buf, sb, dif, &pos);
235 if (err)
236 break;
237 }
238 } else {
239 for (id = 0; id < ondisk_extradevs; id++) {
240 dif = kzalloc(sizeof(*dif), GFP_KERNEL);
241 if (!dif) {
242 err = -ENOMEM;
243 break;
244 }
245
246 err = idr_alloc(&sbi->devs->tree, dif, 0, 0, GFP_KERNEL);
247 if (err < 0) {
248 kfree(dif);
249 break;
250 }
251 ++sbi->devs->extra_devices;
252
253 err = erofs_init_device(&buf, sb, dif, &pos);
254 if (err)
255 break;
256 }
257 }
258 up_read(&sbi->devs->rwsem);
259 erofs_put_metabuf(&buf);
260 return err;
261 }
262
erofs_read_superblock(struct super_block * sb)263 static int erofs_read_superblock(struct super_block *sb)
264 {
265 struct erofs_sb_info *sbi = EROFS_SB(sb);
266 struct erofs_buf buf = __EROFS_BUF_INITIALIZER;
267 struct erofs_super_block *dsb;
268 void *data;
269 int ret;
270
271 data = erofs_read_metabuf(&buf, sb, 0, false);
272 if (IS_ERR(data)) {
273 erofs_err(sb, "cannot read erofs superblock");
274 return PTR_ERR(data);
275 }
276
277 dsb = (struct erofs_super_block *)(data + EROFS_SUPER_OFFSET);
278 ret = -EINVAL;
279 if (le32_to_cpu(dsb->magic) != EROFS_SUPER_MAGIC_V1) {
280 erofs_err(sb, "cannot find valid erofs superblock");
281 goto out;
282 }
283
284 sbi->blkszbits = dsb->blkszbits;
285 if (sbi->blkszbits < 9 || sbi->blkszbits > PAGE_SHIFT) {
286 erofs_err(sb, "blkszbits %u isn't supported", sbi->blkszbits);
287 goto out;
288 }
289 if (dsb->dirblkbits) {
290 erofs_err(sb, "dirblkbits %u isn't supported", dsb->dirblkbits);
291 goto out;
292 }
293
294 sbi->feature_compat = le32_to_cpu(dsb->feature_compat);
295 if (erofs_sb_has_sb_chksum(sbi)) {
296 ret = erofs_superblock_csum_verify(sb, data);
297 if (ret)
298 goto out;
299 }
300
301 ret = -EINVAL;
302 sbi->feature_incompat = le32_to_cpu(dsb->feature_incompat);
303 if (sbi->feature_incompat & ~EROFS_ALL_FEATURE_INCOMPAT) {
304 erofs_err(sb, "unidentified incompatible feature %x, please upgrade kernel",
305 sbi->feature_incompat & ~EROFS_ALL_FEATURE_INCOMPAT);
306 goto out;
307 }
308
309 sbi->sb_size = 128 + dsb->sb_extslots * EROFS_SB_EXTSLOT_SIZE;
310 if (sbi->sb_size > PAGE_SIZE - EROFS_SUPER_OFFSET) {
311 erofs_err(sb, "invalid sb_extslots %u (more than a fs block)",
312 sbi->sb_size);
313 goto out;
314 }
315 sbi->dif0.blocks = le32_to_cpu(dsb->blocks_lo);
316 sbi->meta_blkaddr = le32_to_cpu(dsb->meta_blkaddr);
317 #ifdef CONFIG_EROFS_FS_XATTR
318 sbi->xattr_blkaddr = le32_to_cpu(dsb->xattr_blkaddr);
319 sbi->xattr_prefix_start = le32_to_cpu(dsb->xattr_prefix_start);
320 sbi->xattr_prefix_count = dsb->xattr_prefix_count;
321 sbi->xattr_filter_reserved = dsb->xattr_filter_reserved;
322 #endif
323 sbi->islotbits = ilog2(sizeof(struct erofs_inode_compact));
324 if (erofs_sb_has_48bit(sbi) && dsb->rootnid_8b) {
325 sbi->root_nid = le64_to_cpu(dsb->rootnid_8b);
326 sbi->dif0.blocks = sbi->dif0.blocks |
327 ((u64)le16_to_cpu(dsb->rb.blocks_hi) << 32);
328 } else {
329 sbi->root_nid = le16_to_cpu(dsb->rb.rootnid_2b);
330 }
331 sbi->packed_nid = le64_to_cpu(dsb->packed_nid);
332 if (erofs_sb_has_metabox(sbi)) {
333 if (sbi->sb_size <= offsetof(struct erofs_super_block,
334 metabox_nid))
335 return -EFSCORRUPTED;
336 sbi->metabox_nid = le64_to_cpu(dsb->metabox_nid);
337 if (sbi->metabox_nid & BIT_ULL(EROFS_DIRENT_NID_METABOX_BIT))
338 return -EFSCORRUPTED; /* self-loop detection */
339 }
340 sbi->inos = le64_to_cpu(dsb->inos);
341
342 sbi->epoch = (s64)le64_to_cpu(dsb->epoch);
343 sbi->fixed_nsec = le32_to_cpu(dsb->fixed_nsec);
344 super_set_uuid(sb, (void *)dsb->uuid, sizeof(dsb->uuid));
345
346 if (dsb->volume_name[0]) {
347 sbi->volume_name = kstrndup(dsb->volume_name,
348 sizeof(dsb->volume_name), GFP_KERNEL);
349 if (!sbi->volume_name)
350 return -ENOMEM;
351 }
352
353 /* parse on-disk compression configurations */
354 ret = z_erofs_parse_cfgs(sb, dsb);
355 if (ret < 0)
356 goto out;
357
358 ret = erofs_scan_devices(sb, dsb);
359
360 if (erofs_sb_has_48bit(sbi))
361 erofs_info(sb, "EXPERIMENTAL 48-bit layout support in use. Use at your own risk!");
362 if (erofs_sb_has_metabox(sbi))
363 erofs_info(sb, "EXPERIMENTAL metadata compression support in use. Use at your own risk!");
364 if (erofs_is_fscache_mode(sb))
365 erofs_info(sb, "[deprecated] fscache-based on-demand read feature in use. Use at your own risk!");
366 out:
367 erofs_put_metabuf(&buf);
368 return ret;
369 }
370
erofs_default_options(struct erofs_sb_info * sbi)371 static void erofs_default_options(struct erofs_sb_info *sbi)
372 {
373 #ifdef CONFIG_EROFS_FS_ZIP
374 sbi->opt.cache_strategy = EROFS_ZIP_CACHE_READAROUND;
375 sbi->opt.max_sync_decompress_pages = 3;
376 sbi->opt.sync_decompress = EROFS_SYNC_DECOMPRESS_AUTO;
377 #endif
378 #ifdef CONFIG_EROFS_FS_XATTR
379 set_opt(&sbi->opt, XATTR_USER);
380 #endif
381 #ifdef CONFIG_EROFS_FS_POSIX_ACL
382 set_opt(&sbi->opt, POSIX_ACL);
383 #endif
384 }
385
386 enum {
387 Opt_user_xattr, Opt_acl, Opt_cache_strategy, Opt_dax, Opt_dax_enum,
388 Opt_device, Opt_fsid, Opt_domain_id, Opt_directio, Opt_fsoffset,
389 };
390
391 static const struct constant_table erofs_param_cache_strategy[] = {
392 {"disabled", EROFS_ZIP_CACHE_DISABLED},
393 {"readahead", EROFS_ZIP_CACHE_READAHEAD},
394 {"readaround", EROFS_ZIP_CACHE_READAROUND},
395 {}
396 };
397
398 static const struct constant_table erofs_dax_param_enums[] = {
399 {"always", EROFS_MOUNT_DAX_ALWAYS},
400 {"never", EROFS_MOUNT_DAX_NEVER},
401 {}
402 };
403
404 static const struct fs_parameter_spec erofs_fs_parameters[] = {
405 fsparam_flag_no("user_xattr", Opt_user_xattr),
406 fsparam_flag_no("acl", Opt_acl),
407 fsparam_enum("cache_strategy", Opt_cache_strategy,
408 erofs_param_cache_strategy),
409 fsparam_flag("dax", Opt_dax),
410 fsparam_enum("dax", Opt_dax_enum, erofs_dax_param_enums),
411 fsparam_string("device", Opt_device),
412 fsparam_string("fsid", Opt_fsid),
413 fsparam_string("domain_id", Opt_domain_id),
414 fsparam_flag_no("directio", Opt_directio),
415 fsparam_u64("fsoffset", Opt_fsoffset),
416 {}
417 };
418
erofs_fc_set_dax_mode(struct fs_context * fc,unsigned int mode)419 static bool erofs_fc_set_dax_mode(struct fs_context *fc, unsigned int mode)
420 {
421 #ifdef CONFIG_FS_DAX
422 struct erofs_sb_info *sbi = fc->s_fs_info;
423
424 switch (mode) {
425 case EROFS_MOUNT_DAX_ALWAYS:
426 set_opt(&sbi->opt, DAX_ALWAYS);
427 clear_opt(&sbi->opt, DAX_NEVER);
428 return true;
429 case EROFS_MOUNT_DAX_NEVER:
430 set_opt(&sbi->opt, DAX_NEVER);
431 clear_opt(&sbi->opt, DAX_ALWAYS);
432 return true;
433 default:
434 DBG_BUGON(1);
435 return false;
436 }
437 #else
438 errorfc(fc, "dax options not supported");
439 return false;
440 #endif
441 }
442
erofs_fc_parse_param(struct fs_context * fc,struct fs_parameter * param)443 static int erofs_fc_parse_param(struct fs_context *fc,
444 struct fs_parameter *param)
445 {
446 struct erofs_sb_info *sbi = fc->s_fs_info;
447 struct fs_parse_result result;
448 struct erofs_device_info *dif;
449 int opt, ret;
450
451 opt = fs_parse(fc, erofs_fs_parameters, param, &result);
452 if (opt < 0)
453 return opt;
454
455 switch (opt) {
456 case Opt_user_xattr:
457 #ifdef CONFIG_EROFS_FS_XATTR
458 if (result.boolean)
459 set_opt(&sbi->opt, XATTR_USER);
460 else
461 clear_opt(&sbi->opt, XATTR_USER);
462 #else
463 errorfc(fc, "{,no}user_xattr options not supported");
464 #endif
465 break;
466 case Opt_acl:
467 #ifdef CONFIG_EROFS_FS_POSIX_ACL
468 if (result.boolean)
469 set_opt(&sbi->opt, POSIX_ACL);
470 else
471 clear_opt(&sbi->opt, POSIX_ACL);
472 #else
473 errorfc(fc, "{,no}acl options not supported");
474 #endif
475 break;
476 case Opt_cache_strategy:
477 #ifdef CONFIG_EROFS_FS_ZIP
478 sbi->opt.cache_strategy = result.uint_32;
479 #else
480 errorfc(fc, "compression not supported, cache_strategy ignored");
481 #endif
482 break;
483 case Opt_dax:
484 if (!erofs_fc_set_dax_mode(fc, EROFS_MOUNT_DAX_ALWAYS))
485 return -EINVAL;
486 break;
487 case Opt_dax_enum:
488 if (!erofs_fc_set_dax_mode(fc, result.uint_32))
489 return -EINVAL;
490 break;
491 case Opt_device:
492 dif = kzalloc(sizeof(*dif), GFP_KERNEL);
493 if (!dif)
494 return -ENOMEM;
495 dif->path = kstrdup(param->string, GFP_KERNEL);
496 if (!dif->path) {
497 kfree(dif);
498 return -ENOMEM;
499 }
500 down_write(&sbi->devs->rwsem);
501 ret = idr_alloc(&sbi->devs->tree, dif, 0, 0, GFP_KERNEL);
502 up_write(&sbi->devs->rwsem);
503 if (ret < 0) {
504 kfree(dif->path);
505 kfree(dif);
506 return ret;
507 }
508 ++sbi->devs->extra_devices;
509 break;
510 #ifdef CONFIG_EROFS_FS_ONDEMAND
511 case Opt_fsid:
512 kfree(sbi->fsid);
513 sbi->fsid = kstrdup(param->string, GFP_KERNEL);
514 if (!sbi->fsid)
515 return -ENOMEM;
516 break;
517 case Opt_domain_id:
518 kfree(sbi->domain_id);
519 sbi->domain_id = kstrdup(param->string, GFP_KERNEL);
520 if (!sbi->domain_id)
521 return -ENOMEM;
522 break;
523 #else
524 case Opt_fsid:
525 case Opt_domain_id:
526 errorfc(fc, "%s option not supported", erofs_fs_parameters[opt].name);
527 break;
528 #endif
529 case Opt_directio:
530 #ifdef CONFIG_EROFS_FS_BACKED_BY_FILE
531 if (result.boolean)
532 set_opt(&sbi->opt, DIRECT_IO);
533 else
534 clear_opt(&sbi->opt, DIRECT_IO);
535 #else
536 errorfc(fc, "%s option not supported", erofs_fs_parameters[opt].name);
537 #endif
538 break;
539 case Opt_fsoffset:
540 sbi->dif0.fsoff = result.uint_64;
541 break;
542 }
543 return 0;
544 }
545
erofs_encode_fh(struct inode * inode,u32 * fh,int * max_len,struct inode * parent)546 static int erofs_encode_fh(struct inode *inode, u32 *fh, int *max_len,
547 struct inode *parent)
548 {
549 erofs_nid_t nid = EROFS_I(inode)->nid;
550 int len = parent ? 6 : 3;
551
552 if (*max_len < len) {
553 *max_len = len;
554 return FILEID_INVALID;
555 }
556
557 fh[0] = (u32)(nid >> 32);
558 fh[1] = (u32)(nid & 0xffffffff);
559 fh[2] = inode->i_generation;
560
561 if (parent) {
562 nid = EROFS_I(parent)->nid;
563
564 fh[3] = (u32)(nid >> 32);
565 fh[4] = (u32)(nid & 0xffffffff);
566 fh[5] = parent->i_generation;
567 }
568
569 *max_len = len;
570 return parent ? FILEID_INO64_GEN_PARENT : FILEID_INO64_GEN;
571 }
572
erofs_fh_to_dentry(struct super_block * sb,struct fid * fid,int fh_len,int fh_type)573 static struct dentry *erofs_fh_to_dentry(struct super_block *sb,
574 struct fid *fid, int fh_len, int fh_type)
575 {
576 if ((fh_type != FILEID_INO64_GEN &&
577 fh_type != FILEID_INO64_GEN_PARENT) || fh_len < 3)
578 return NULL;
579
580 return d_obtain_alias(erofs_iget(sb,
581 ((u64)fid->raw[0] << 32) | fid->raw[1]));
582 }
583
erofs_fh_to_parent(struct super_block * sb,struct fid * fid,int fh_len,int fh_type)584 static struct dentry *erofs_fh_to_parent(struct super_block *sb,
585 struct fid *fid, int fh_len, int fh_type)
586 {
587 if (fh_type != FILEID_INO64_GEN_PARENT || fh_len < 6)
588 return NULL;
589
590 return d_obtain_alias(erofs_iget(sb,
591 ((u64)fid->raw[3] << 32) | fid->raw[4]));
592 }
593
erofs_get_parent(struct dentry * child)594 static struct dentry *erofs_get_parent(struct dentry *child)
595 {
596 erofs_nid_t nid;
597 unsigned int d_type;
598 int err;
599
600 err = erofs_namei(d_inode(child), &dotdot_name, &nid, &d_type);
601 if (err)
602 return ERR_PTR(err);
603 return d_obtain_alias(erofs_iget(child->d_sb, nid));
604 }
605
606 static const struct export_operations erofs_export_ops = {
607 .encode_fh = erofs_encode_fh,
608 .fh_to_dentry = erofs_fh_to_dentry,
609 .fh_to_parent = erofs_fh_to_parent,
610 .get_parent = erofs_get_parent,
611 };
612
erofs_set_sysfs_name(struct super_block * sb)613 static void erofs_set_sysfs_name(struct super_block *sb)
614 {
615 struct erofs_sb_info *sbi = EROFS_SB(sb);
616
617 if (sbi->domain_id)
618 super_set_sysfs_name_generic(sb, "%s,%s", sbi->domain_id,
619 sbi->fsid);
620 else if (sbi->fsid)
621 super_set_sysfs_name_generic(sb, "%s", sbi->fsid);
622 else if (erofs_is_fileio_mode(sbi))
623 super_set_sysfs_name_generic(sb, "%s",
624 bdi_dev_name(sb->s_bdi));
625 else
626 super_set_sysfs_name_id(sb);
627 }
628
erofs_fc_fill_super(struct super_block * sb,struct fs_context * fc)629 static int erofs_fc_fill_super(struct super_block *sb, struct fs_context *fc)
630 {
631 struct inode *inode;
632 struct erofs_sb_info *sbi = EROFS_SB(sb);
633 int err;
634
635 sb->s_magic = EROFS_SUPER_MAGIC;
636 sb->s_flags |= SB_RDONLY | SB_NOATIME;
637 sb->s_maxbytes = MAX_LFS_FILESIZE;
638 sb->s_op = &erofs_sops;
639
640 sbi->blkszbits = PAGE_SHIFT;
641 if (!sb->s_bdev) {
642 sb->s_blocksize = PAGE_SIZE;
643 sb->s_blocksize_bits = PAGE_SHIFT;
644
645 if (erofs_is_fscache_mode(sb)) {
646 err = erofs_fscache_register_fs(sb);
647 if (err)
648 return err;
649 }
650 err = super_setup_bdi(sb);
651 if (err)
652 return err;
653 } else {
654 if (!sb_set_blocksize(sb, PAGE_SIZE)) {
655 errorfc(fc, "failed to set initial blksize");
656 return -EINVAL;
657 }
658
659 sbi->dif0.dax_dev = fs_dax_get_by_bdev(sb->s_bdev,
660 &sbi->dif0.dax_part_off, NULL, NULL);
661 }
662
663 err = erofs_read_superblock(sb);
664 if (err)
665 return err;
666
667 if (sb->s_blocksize_bits != sbi->blkszbits) {
668 if (erofs_is_fscache_mode(sb)) {
669 errorfc(fc, "unsupported blksize for fscache mode");
670 return -EINVAL;
671 }
672
673 if (erofs_is_fileio_mode(sbi)) {
674 sb->s_blocksize = 1 << sbi->blkszbits;
675 sb->s_blocksize_bits = sbi->blkszbits;
676 } else if (!sb_set_blocksize(sb, 1 << sbi->blkszbits)) {
677 errorfc(fc, "failed to set erofs blksize");
678 return -EINVAL;
679 }
680 }
681
682 if (sbi->dif0.fsoff) {
683 if (sbi->dif0.fsoff & (sb->s_blocksize - 1))
684 return invalfc(fc, "fsoffset %llu is not aligned to block size %lu",
685 sbi->dif0.fsoff, sb->s_blocksize);
686 if (erofs_is_fscache_mode(sb))
687 return invalfc(fc, "cannot use fsoffset in fscache mode");
688 }
689
690 if (test_opt(&sbi->opt, DAX_ALWAYS) && sbi->blkszbits != PAGE_SHIFT) {
691 erofs_info(sb, "unsupported blocksize for DAX");
692 clear_opt(&sbi->opt, DAX_ALWAYS);
693 }
694
695 sb->s_time_gran = 1;
696 sb->s_xattr = erofs_xattr_handlers;
697 sb->s_export_op = &erofs_export_ops;
698
699 if (test_opt(&sbi->opt, POSIX_ACL))
700 sb->s_flags |= SB_POSIXACL;
701 else
702 sb->s_flags &= ~SB_POSIXACL;
703
704 err = z_erofs_init_super(sb);
705 if (err)
706 return err;
707
708 if (erofs_sb_has_fragments(sbi) && sbi->packed_nid) {
709 inode = erofs_iget(sb, sbi->packed_nid);
710 if (IS_ERR(inode))
711 return PTR_ERR(inode);
712 sbi->packed_inode = inode;
713 }
714 if (erofs_sb_has_metabox(sbi)) {
715 inode = erofs_iget(sb, sbi->metabox_nid);
716 if (IS_ERR(inode))
717 return PTR_ERR(inode);
718 sbi->metabox_inode = inode;
719 }
720
721 inode = erofs_iget(sb, sbi->root_nid);
722 if (IS_ERR(inode))
723 return PTR_ERR(inode);
724
725 if (!S_ISDIR(inode->i_mode)) {
726 erofs_err(sb, "rootino(nid %llu) is not a directory(i_mode %o)",
727 sbi->root_nid, inode->i_mode);
728 iput(inode);
729 return -EINVAL;
730 }
731 sb->s_root = d_make_root(inode);
732 if (!sb->s_root)
733 return -ENOMEM;
734
735 erofs_shrinker_register(sb);
736 err = erofs_xattr_prefixes_init(sb);
737 if (err)
738 return err;
739
740 erofs_set_sysfs_name(sb);
741 err = erofs_register_sysfs(sb);
742 if (err)
743 return err;
744
745 sbi->dir_ra_bytes = EROFS_DIR_RA_BYTES;
746 erofs_info(sb, "mounted with root inode @ nid %llu.", sbi->root_nid);
747 return 0;
748 }
749
erofs_fc_get_tree(struct fs_context * fc)750 static int erofs_fc_get_tree(struct fs_context *fc)
751 {
752 struct erofs_sb_info *sbi = fc->s_fs_info;
753 int ret;
754
755 if (IS_ENABLED(CONFIG_EROFS_FS_ONDEMAND) && sbi->fsid)
756 return get_tree_nodev(fc, erofs_fc_fill_super);
757
758 ret = get_tree_bdev_flags(fc, erofs_fc_fill_super,
759 IS_ENABLED(CONFIG_EROFS_FS_BACKED_BY_FILE) ?
760 GET_TREE_BDEV_QUIET_LOOKUP : 0);
761 #ifdef CONFIG_EROFS_FS_BACKED_BY_FILE
762 if (ret == -ENOTBLK) {
763 struct file *file;
764
765 if (!fc->source)
766 return invalf(fc, "No source specified");
767 file = filp_open(fc->source, O_RDONLY | O_LARGEFILE, 0);
768 if (IS_ERR(file))
769 return PTR_ERR(file);
770 sbi->dif0.file = file;
771
772 if (S_ISREG(file_inode(sbi->dif0.file)->i_mode) &&
773 sbi->dif0.file->f_mapping->a_ops->read_folio)
774 return get_tree_nodev(fc, erofs_fc_fill_super);
775 }
776 #endif
777 return ret;
778 }
779
erofs_fc_reconfigure(struct fs_context * fc)780 static int erofs_fc_reconfigure(struct fs_context *fc)
781 {
782 struct super_block *sb = fc->root->d_sb;
783 struct erofs_sb_info *sbi = EROFS_SB(sb);
784 struct erofs_sb_info *new_sbi = fc->s_fs_info;
785
786 DBG_BUGON(!sb_rdonly(sb));
787
788 if (new_sbi->fsid || new_sbi->domain_id)
789 erofs_info(sb, "ignoring reconfiguration for fsid|domain_id.");
790
791 if (test_opt(&new_sbi->opt, POSIX_ACL))
792 fc->sb_flags |= SB_POSIXACL;
793 else
794 fc->sb_flags &= ~SB_POSIXACL;
795
796 sbi->opt = new_sbi->opt;
797
798 fc->sb_flags |= SB_RDONLY;
799 return 0;
800 }
801
erofs_release_device_info(int id,void * ptr,void * data)802 static int erofs_release_device_info(int id, void *ptr, void *data)
803 {
804 struct erofs_device_info *dif = ptr;
805
806 fs_put_dax(dif->dax_dev, NULL);
807 if (dif->file)
808 fput(dif->file);
809 erofs_fscache_unregister_cookie(dif->fscache);
810 dif->fscache = NULL;
811 kfree(dif->path);
812 kfree(dif);
813 return 0;
814 }
815
erofs_free_dev_context(struct erofs_dev_context * devs)816 static void erofs_free_dev_context(struct erofs_dev_context *devs)
817 {
818 if (!devs)
819 return;
820 idr_for_each(&devs->tree, &erofs_release_device_info, NULL);
821 idr_destroy(&devs->tree);
822 kfree(devs);
823 }
824
erofs_sb_free(struct erofs_sb_info * sbi)825 static void erofs_sb_free(struct erofs_sb_info *sbi)
826 {
827 erofs_free_dev_context(sbi->devs);
828 kfree(sbi->fsid);
829 kfree(sbi->domain_id);
830 if (sbi->dif0.file)
831 fput(sbi->dif0.file);
832 kfree(sbi->volume_name);
833 kfree(sbi);
834 }
835
erofs_fc_free(struct fs_context * fc)836 static void erofs_fc_free(struct fs_context *fc)
837 {
838 struct erofs_sb_info *sbi = fc->s_fs_info;
839
840 if (sbi) /* free here if an error occurs before transferring to sb */
841 erofs_sb_free(sbi);
842 }
843
844 static const struct fs_context_operations erofs_context_ops = {
845 .parse_param = erofs_fc_parse_param,
846 .get_tree = erofs_fc_get_tree,
847 .reconfigure = erofs_fc_reconfigure,
848 .free = erofs_fc_free,
849 };
850
erofs_init_fs_context(struct fs_context * fc)851 static int erofs_init_fs_context(struct fs_context *fc)
852 {
853 struct erofs_sb_info *sbi;
854
855 sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
856 if (!sbi)
857 return -ENOMEM;
858
859 sbi->devs = kzalloc(sizeof(struct erofs_dev_context), GFP_KERNEL);
860 if (!sbi->devs) {
861 kfree(sbi);
862 return -ENOMEM;
863 }
864 fc->s_fs_info = sbi;
865
866 idr_init(&sbi->devs->tree);
867 init_rwsem(&sbi->devs->rwsem);
868 erofs_default_options(sbi);
869 fc->ops = &erofs_context_ops;
870 return 0;
871 }
872
erofs_drop_internal_inodes(struct erofs_sb_info * sbi)873 static void erofs_drop_internal_inodes(struct erofs_sb_info *sbi)
874 {
875 iput(sbi->packed_inode);
876 sbi->packed_inode = NULL;
877 iput(sbi->metabox_inode);
878 sbi->metabox_inode = NULL;
879 #ifdef CONFIG_EROFS_FS_ZIP
880 iput(sbi->managed_cache);
881 sbi->managed_cache = NULL;
882 #endif
883 }
884
erofs_kill_sb(struct super_block * sb)885 static void erofs_kill_sb(struct super_block *sb)
886 {
887 struct erofs_sb_info *sbi = EROFS_SB(sb);
888
889 if ((IS_ENABLED(CONFIG_EROFS_FS_ONDEMAND) && sbi->fsid) ||
890 sbi->dif0.file)
891 kill_anon_super(sb);
892 else
893 kill_block_super(sb);
894 erofs_drop_internal_inodes(sbi);
895 fs_put_dax(sbi->dif0.dax_dev, NULL);
896 erofs_fscache_unregister_fs(sb);
897 erofs_sb_free(sbi);
898 sb->s_fs_info = NULL;
899 }
900
erofs_put_super(struct super_block * sb)901 static void erofs_put_super(struct super_block *sb)
902 {
903 struct erofs_sb_info *const sbi = EROFS_SB(sb);
904
905 erofs_unregister_sysfs(sb);
906 erofs_shrinker_unregister(sb);
907 erofs_xattr_prefixes_cleanup(sb);
908 erofs_drop_internal_inodes(sbi);
909 erofs_free_dev_context(sbi->devs);
910 sbi->devs = NULL;
911 erofs_fscache_unregister_fs(sb);
912 }
913
914 static struct file_system_type erofs_fs_type = {
915 .owner = THIS_MODULE,
916 .name = "erofs",
917 .init_fs_context = erofs_init_fs_context,
918 .kill_sb = erofs_kill_sb,
919 .fs_flags = FS_REQUIRES_DEV | FS_ALLOW_IDMAP,
920 };
921 MODULE_ALIAS_FS("erofs");
922
erofs_module_init(void)923 static int __init erofs_module_init(void)
924 {
925 int err;
926
927 erofs_check_ondisk_layout_definitions();
928
929 erofs_inode_cachep = kmem_cache_create("erofs_inode",
930 sizeof(struct erofs_inode), 0,
931 SLAB_RECLAIM_ACCOUNT | SLAB_ACCOUNT,
932 erofs_inode_init_once);
933 if (!erofs_inode_cachep)
934 return -ENOMEM;
935
936 err = erofs_init_shrinker();
937 if (err)
938 goto shrinker_err;
939
940 err = z_erofs_init_subsystem();
941 if (err)
942 goto zip_err;
943
944 err = erofs_init_sysfs();
945 if (err)
946 goto sysfs_err;
947
948 err = register_filesystem(&erofs_fs_type);
949 if (err)
950 goto fs_err;
951
952 return 0;
953
954 fs_err:
955 erofs_exit_sysfs();
956 sysfs_err:
957 z_erofs_exit_subsystem();
958 zip_err:
959 erofs_exit_shrinker();
960 shrinker_err:
961 kmem_cache_destroy(erofs_inode_cachep);
962 return err;
963 }
964
erofs_module_exit(void)965 static void __exit erofs_module_exit(void)
966 {
967 unregister_filesystem(&erofs_fs_type);
968
969 /* Ensure all RCU free inodes / pclusters are safe to be destroyed. */
970 rcu_barrier();
971
972 erofs_exit_sysfs();
973 z_erofs_exit_subsystem();
974 erofs_exit_shrinker();
975 kmem_cache_destroy(erofs_inode_cachep);
976 }
977
erofs_statfs(struct dentry * dentry,struct kstatfs * buf)978 static int erofs_statfs(struct dentry *dentry, struct kstatfs *buf)
979 {
980 struct super_block *sb = dentry->d_sb;
981 struct erofs_sb_info *sbi = EROFS_SB(sb);
982
983 buf->f_type = sb->s_magic;
984 buf->f_bsize = sb->s_blocksize;
985 buf->f_blocks = sbi->total_blocks;
986 buf->f_bfree = buf->f_bavail = 0;
987 buf->f_files = ULLONG_MAX;
988 buf->f_ffree = ULLONG_MAX - sbi->inos;
989 buf->f_namelen = EROFS_NAME_LEN;
990
991 if (uuid_is_null(&sb->s_uuid))
992 buf->f_fsid = u64_to_fsid(!sb->s_bdev ? 0 :
993 huge_encode_dev(sb->s_bdev->bd_dev));
994 else
995 buf->f_fsid = uuid_to_fsid(sb->s_uuid.b);
996 return 0;
997 }
998
erofs_show_options(struct seq_file * seq,struct dentry * root)999 static int erofs_show_options(struct seq_file *seq, struct dentry *root)
1000 {
1001 struct erofs_sb_info *sbi = EROFS_SB(root->d_sb);
1002 struct erofs_mount_opts *opt = &sbi->opt;
1003
1004 if (IS_ENABLED(CONFIG_EROFS_FS_XATTR))
1005 seq_puts(seq, test_opt(opt, XATTR_USER) ?
1006 ",user_xattr" : ",nouser_xattr");
1007 if (IS_ENABLED(CONFIG_EROFS_FS_POSIX_ACL))
1008 seq_puts(seq, test_opt(opt, POSIX_ACL) ? ",acl" : ",noacl");
1009 if (IS_ENABLED(CONFIG_EROFS_FS_ZIP))
1010 seq_printf(seq, ",cache_strategy=%s",
1011 erofs_param_cache_strategy[opt->cache_strategy].name);
1012 if (test_opt(opt, DAX_ALWAYS))
1013 seq_puts(seq, ",dax=always");
1014 if (test_opt(opt, DAX_NEVER))
1015 seq_puts(seq, ",dax=never");
1016 if (erofs_is_fileio_mode(sbi) && test_opt(opt, DIRECT_IO))
1017 seq_puts(seq, ",directio");
1018 #ifdef CONFIG_EROFS_FS_ONDEMAND
1019 if (sbi->fsid)
1020 seq_printf(seq, ",fsid=%s", sbi->fsid);
1021 if (sbi->domain_id)
1022 seq_printf(seq, ",domain_id=%s", sbi->domain_id);
1023 #endif
1024 if (sbi->dif0.fsoff)
1025 seq_printf(seq, ",fsoffset=%llu", sbi->dif0.fsoff);
1026 return 0;
1027 }
1028
erofs_evict_inode(struct inode * inode)1029 static void erofs_evict_inode(struct inode *inode)
1030 {
1031 #ifdef CONFIG_FS_DAX
1032 if (IS_DAX(inode))
1033 dax_break_layout_final(inode);
1034 #endif
1035
1036 truncate_inode_pages_final(&inode->i_data);
1037 clear_inode(inode);
1038 }
1039
1040 const struct super_operations erofs_sops = {
1041 .put_super = erofs_put_super,
1042 .alloc_inode = erofs_alloc_inode,
1043 .free_inode = erofs_free_inode,
1044 .evict_inode = erofs_evict_inode,
1045 .statfs = erofs_statfs,
1046 .show_options = erofs_show_options,
1047 };
1048
1049 module_init(erofs_module_init);
1050 module_exit(erofs_module_exit);
1051
1052 MODULE_DESCRIPTION("Enhanced ROM File System");
1053 MODULE_AUTHOR("Gao Xiang, Chao Yu, Miao Xie, CONSUMER BG, HUAWEI Inc.");
1054 MODULE_LICENSE("GPL");
1055