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 <linux/pseudo_fs.h>
15 #include "xattr.h"
16
17 #define CREATE_TRACE_POINTS
18 #include <trace/events/erofs.h>
19
20 static struct kmem_cache *erofs_inode_cachep __read_mostly;
21
_erofs_printk(struct super_block * sb,const char * fmt,...)22 void _erofs_printk(struct super_block *sb, const char *fmt, ...)
23 {
24 struct va_format vaf;
25 va_list args;
26 int level;
27
28 va_start(args, fmt);
29
30 level = printk_get_level(fmt);
31 vaf.fmt = printk_skip_level(fmt);
32 vaf.va = &args;
33 if (sb)
34 printk("%c%cerofs (device %s): %pV",
35 KERN_SOH_ASCII, level, sb->s_id, &vaf);
36 else
37 printk("%c%cerofs: %pV", KERN_SOH_ASCII, level, &vaf);
38 va_end(args);
39 }
40
erofs_superblock_csum_verify(struct super_block * sb,void * sbdata)41 static int erofs_superblock_csum_verify(struct super_block *sb, void *sbdata)
42 {
43 struct erofs_super_block *dsb = sbdata + EROFS_SUPER_OFFSET;
44 u32 len = 1 << EROFS_SB(sb)->blkszbits, crc;
45
46 if (len > EROFS_SUPER_OFFSET)
47 len -= EROFS_SUPER_OFFSET;
48 len -= offsetof(struct erofs_super_block, checksum) +
49 sizeof(dsb->checksum);
50
51 /* skip .magic(pre-verified) and .checksum(0) fields */
52 crc = crc32c(0x5045B54A, (&dsb->checksum) + 1, len);
53 if (crc == le32_to_cpu(dsb->checksum))
54 return 0;
55 erofs_err(sb, "invalid checksum 0x%08x, 0x%08x expected",
56 crc, le32_to_cpu(dsb->checksum));
57 return -EBADMSG;
58 }
59
erofs_inode_init_once(void * ptr)60 static void erofs_inode_init_once(void *ptr)
61 {
62 struct erofs_inode *vi = ptr;
63
64 inode_init_once(&vi->vfs_inode);
65 }
66
erofs_alloc_inode(struct super_block * sb)67 static struct inode *erofs_alloc_inode(struct super_block *sb)
68 {
69 struct erofs_inode *vi =
70 alloc_inode_sb(sb, erofs_inode_cachep, GFP_KERNEL);
71
72 if (!vi)
73 return NULL;
74
75 /* zero out everything except vfs_inode */
76 memset(vi, 0, offsetof(struct erofs_inode, vfs_inode));
77 return &vi->vfs_inode;
78 }
79
erofs_free_inode(struct inode * inode)80 static void erofs_free_inode(struct inode *inode)
81 {
82 struct erofs_inode *vi = EROFS_I(inode);
83
84 if (inode->i_op == &erofs_fast_symlink_iops)
85 kfree(inode->i_link);
86 kfree(vi->xattr_shared_xattrs);
87 kmem_cache_free(erofs_inode_cachep, vi);
88 }
89
90 /* 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)91 void *erofs_read_metadata(struct super_block *sb, struct erofs_buf *buf,
92 erofs_off_t *offset, int *lengthp)
93 {
94 u8 *buffer, *ptr;
95 int len, i, cnt;
96
97 *offset = round_up(*offset, 4);
98 ptr = erofs_bread(buf, *offset, true);
99 if (IS_ERR(ptr))
100 return ptr;
101
102 len = le16_to_cpu(*(__le16 *)ptr);
103 if (!len)
104 len = U16_MAX + 1;
105 buffer = kmalloc(len, GFP_KERNEL);
106 if (!buffer)
107 return ERR_PTR(-ENOMEM);
108 *offset += sizeof(__le16);
109 *lengthp = len;
110
111 for (i = 0; i < len; i += cnt) {
112 cnt = min_t(int, sb->s_blocksize - erofs_blkoff(sb, *offset),
113 len - i);
114 ptr = erofs_bread(buf, *offset, true);
115 if (IS_ERR(ptr)) {
116 kfree(buffer);
117 return ptr;
118 }
119 memcpy(buffer + i, ptr, cnt);
120 *offset += cnt;
121 }
122 return buffer;
123 }
124
erofs_init_device(struct erofs_buf * buf,struct super_block * sb,struct erofs_device_info * dif,erofs_off_t * pos)125 static int erofs_init_device(struct erofs_buf *buf, struct super_block *sb,
126 struct erofs_device_info *dif, erofs_off_t *pos)
127 {
128 struct erofs_sb_info *sbi = EROFS_SB(sb);
129 struct erofs_fscache *fscache;
130 struct erofs_deviceslot *dis;
131 struct file *file;
132 bool _48bit;
133
134 dis = erofs_read_metabuf(buf, sb, *pos, false);
135 if (IS_ERR(dis))
136 return PTR_ERR(dis);
137
138 if (!sbi->devs->flatdev && !dif->path) {
139 if (!dis->tag[0]) {
140 erofs_err(sb, "empty device tag @ pos %llu", *pos);
141 return -EINVAL;
142 }
143 dif->path = kmemdup_nul(dis->tag, sizeof(dis->tag), GFP_KERNEL);
144 if (!dif->path)
145 return -ENOMEM;
146 }
147
148 if (erofs_is_fscache_mode(sb)) {
149 fscache = erofs_fscache_register_cookie(sb, dif->path, 0);
150 if (IS_ERR(fscache))
151 return PTR_ERR(fscache);
152 dif->fscache = fscache;
153 } else if (!sbi->devs->flatdev) {
154 file = erofs_is_fileio_mode(sbi) ?
155 filp_open(dif->path, O_RDONLY | O_LARGEFILE, 0) :
156 bdev_file_open_by_path(dif->path,
157 BLK_OPEN_READ, sb->s_type, NULL);
158 if (IS_ERR(file)) {
159 if (file == ERR_PTR(-ENOTBLK))
160 return -EINVAL;
161 return PTR_ERR(file);
162 }
163
164 if (!erofs_is_fileio_mode(sbi)) {
165 dif->dax_dev = fs_dax_get_by_bdev(file_bdev(file),
166 &dif->dax_part_off, NULL, NULL);
167 } else if (!S_ISREG(file_inode(file)->i_mode)) {
168 fput(file);
169 return -EINVAL;
170 }
171 if (!dif->dax_dev && test_opt(&sbi->opt, DAX_ALWAYS)) {
172 erofs_info(sb, "DAX unsupported by %s. Turning off DAX.",
173 dif->path);
174 clear_opt(&sbi->opt, DAX_ALWAYS);
175 }
176 dif->file = file;
177 }
178
179 _48bit = erofs_sb_has_48bit(sbi);
180 dif->blocks = le32_to_cpu(dis->blocks_lo) |
181 (_48bit ? (u64)le16_to_cpu(dis->blocks_hi) << 32 : 0);
182 dif->uniaddr = le32_to_cpu(dis->uniaddr_lo) |
183 (_48bit ? (u64)le16_to_cpu(dis->uniaddr_hi) << 32 : 0);
184 sbi->total_blocks += dif->blocks;
185 *pos += EROFS_DEVT_SLOT_SIZE;
186 return 0;
187 }
188
erofs_scan_devices(struct super_block * sb,struct erofs_super_block * dsb)189 static int erofs_scan_devices(struct super_block *sb,
190 struct erofs_super_block *dsb)
191 {
192 struct erofs_sb_info *sbi = EROFS_SB(sb);
193 unsigned int ondisk_extradevs;
194 erofs_off_t pos;
195 struct erofs_buf buf = __EROFS_BUF_INITIALIZER;
196 struct erofs_device_info *dif;
197 int id, err = 0;
198
199 sbi->total_blocks = sbi->dif0.blocks;
200 if (!erofs_sb_has_device_table(sbi))
201 ondisk_extradevs = 0;
202 else
203 ondisk_extradevs = le16_to_cpu(dsb->extra_devices);
204
205 if (sbi->devs->extra_devices &&
206 ondisk_extradevs != sbi->devs->extra_devices) {
207 erofs_err(sb, "extra devices don't match (ondisk %u, given %u)",
208 ondisk_extradevs, sbi->devs->extra_devices);
209 return -EINVAL;
210 }
211
212 if (test_opt(&sbi->opt, DAX_ALWAYS) && !sbi->dif0.dax_dev) {
213 erofs_info(sb, "DAX unsupported by block device. Turning off DAX.");
214 clear_opt(&sbi->opt, DAX_ALWAYS);
215 }
216 if (!ondisk_extradevs)
217 return 0;
218
219 if (!sbi->devs->extra_devices && !erofs_is_fscache_mode(sb))
220 sbi->devs->flatdev = true;
221
222 sbi->device_id_mask = roundup_pow_of_two(ondisk_extradevs + 1) - 1;
223 pos = le16_to_cpu(dsb->devt_slotoff) * EROFS_DEVT_SLOT_SIZE;
224 down_read(&sbi->devs->rwsem);
225 if (sbi->devs->extra_devices) {
226 idr_for_each_entry(&sbi->devs->tree, dif, id) {
227 err = erofs_init_device(&buf, sb, dif, &pos);
228 if (err)
229 break;
230 }
231 } else {
232 for (id = 0; id < ondisk_extradevs; id++) {
233 dif = kzalloc_obj(*dif);
234 if (!dif) {
235 err = -ENOMEM;
236 break;
237 }
238
239 err = idr_alloc(&sbi->devs->tree, dif, 0, 0, GFP_KERNEL);
240 if (err < 0) {
241 kfree(dif);
242 break;
243 }
244 ++sbi->devs->extra_devices;
245
246 err = erofs_init_device(&buf, sb, dif, &pos);
247 if (err)
248 break;
249 }
250 }
251 up_read(&sbi->devs->rwsem);
252 erofs_put_metabuf(&buf);
253 return err;
254 }
255
erofs_read_superblock(struct super_block * sb)256 static int erofs_read_superblock(struct super_block *sb)
257 {
258 struct erofs_sb_info *sbi = EROFS_SB(sb);
259 struct erofs_buf buf = __EROFS_BUF_INITIALIZER;
260 struct erofs_super_block *dsb;
261 void *data;
262 int ret;
263
264 data = erofs_read_metabuf(&buf, sb, 0, false);
265 if (IS_ERR(data)) {
266 erofs_err(sb, "cannot read erofs superblock");
267 return PTR_ERR(data);
268 }
269
270 dsb = (struct erofs_super_block *)(data + EROFS_SUPER_OFFSET);
271 ret = -EINVAL;
272 if (le32_to_cpu(dsb->magic) != EROFS_SUPER_MAGIC_V1) {
273 erofs_err(sb, "cannot find valid erofs superblock");
274 goto out;
275 }
276
277 sbi->blkszbits = dsb->blkszbits;
278 if (sbi->blkszbits < 9 || sbi->blkszbits > PAGE_SHIFT) {
279 erofs_err(sb, "blkszbits %u isn't supported", sbi->blkszbits);
280 goto out;
281 }
282 if (dsb->dirblkbits) {
283 erofs_err(sb, "dirblkbits %u isn't supported", dsb->dirblkbits);
284 goto out;
285 }
286
287 sbi->feature_compat = le32_to_cpu(dsb->feature_compat);
288 if (erofs_sb_has_sb_chksum(sbi)) {
289 ret = erofs_superblock_csum_verify(sb, data);
290 if (ret)
291 goto out;
292 }
293
294 ret = -EINVAL;
295 sbi->feature_incompat = le32_to_cpu(dsb->feature_incompat);
296 if (sbi->feature_incompat & ~EROFS_ALL_FEATURE_INCOMPAT) {
297 erofs_err(sb, "unidentified incompatible feature %x, please upgrade kernel",
298 sbi->feature_incompat & ~EROFS_ALL_FEATURE_INCOMPAT);
299 goto out;
300 }
301
302 sbi->sb_size = 128 + dsb->sb_extslots * EROFS_SB_EXTSLOT_SIZE;
303 if (sbi->sb_size > PAGE_SIZE - EROFS_SUPER_OFFSET) {
304 erofs_err(sb, "invalid sb_extslots %u (more than a fs block)",
305 sbi->sb_size);
306 goto out;
307 }
308 sbi->dif0.blocks = le32_to_cpu(dsb->blocks_lo);
309 sbi->meta_blkaddr = le32_to_cpu(dsb->meta_blkaddr);
310 #ifdef CONFIG_EROFS_FS_XATTR
311 sbi->xattr_blkaddr = le32_to_cpu(dsb->xattr_blkaddr);
312 sbi->xattr_prefix_start = le32_to_cpu(dsb->xattr_prefix_start);
313 sbi->xattr_prefix_count = dsb->xattr_prefix_count;
314 sbi->xattr_filter_reserved = dsb->xattr_filter_reserved;
315 if (erofs_sb_has_ishare_xattrs(sbi)) {
316 if (dsb->ishare_xattr_prefix_id >= sbi->xattr_prefix_count) {
317 erofs_err(sb, "invalid ishare xattr prefix id %u",
318 dsb->ishare_xattr_prefix_id);
319 ret = -EFSCORRUPTED;
320 goto out;
321 }
322 sbi->ishare_xattr_prefix_id = dsb->ishare_xattr_prefix_id;
323 }
324 #endif
325 sbi->islotbits = ilog2(sizeof(struct erofs_inode_compact));
326 if (erofs_sb_has_48bit(sbi) && dsb->rootnid_8b) {
327 sbi->root_nid = le64_to_cpu(dsb->rootnid_8b);
328 sbi->dif0.blocks = sbi->dif0.blocks |
329 ((u64)le16_to_cpu(dsb->rb.blocks_hi) << 32);
330 } else {
331 sbi->root_nid = le16_to_cpu(dsb->rb.rootnid_2b);
332 }
333 sbi->packed_nid = le64_to_cpu(dsb->packed_nid);
334 if (erofs_sb_has_metabox(sbi)) {
335 ret = -EFSCORRUPTED;
336 if (sbi->sb_size <= offsetof(struct erofs_super_block,
337 metabox_nid))
338 goto out;
339 sbi->metabox_nid = le64_to_cpu(dsb->metabox_nid);
340 if (sbi->metabox_nid & BIT_ULL(EROFS_DIRENT_NID_METABOX_BIT))
341 goto out; /* self-loop detection */
342 }
343 sbi->inos = le64_to_cpu(dsb->inos);
344
345 sbi->epoch = (s64)le64_to_cpu(dsb->epoch);
346 sbi->fixed_nsec = le32_to_cpu(dsb->fixed_nsec);
347 super_set_uuid(sb, (void *)dsb->uuid, sizeof(dsb->uuid));
348
349 if (dsb->volume_name[0]) {
350 sbi->volume_name = kstrndup(dsb->volume_name,
351 sizeof(dsb->volume_name), GFP_KERNEL);
352 if (!sbi->volume_name) {
353 ret = -ENOMEM;
354 goto out;
355 }
356 }
357
358 if (IS_ENABLED(CONFIG_EROFS_FS_ZIP)) {
359 ret = z_erofs_parse_cfgs(sb, dsb);
360 if (ret < 0)
361 goto out;
362 } else if (dsb->u1.available_compr_algs ||
363 erofs_sb_has_lz4_0padding(sbi)) {
364 erofs_err(sb, "compression disabled, unable to mount compressed EROFS");
365 ret = -EOPNOTSUPP;
366 goto out;
367 }
368
369 ret = erofs_scan_devices(sb, dsb);
370
371 if (erofs_sb_has_48bit(sbi))
372 erofs_info(sb, "EXPERIMENTAL 48-bit layout support in use. Use at your own risk!");
373 if (erofs_sb_has_metabox(sbi))
374 erofs_info(sb, "EXPERIMENTAL metadata compression support in use. Use at your own risk!");
375 if (erofs_is_fscache_mode(sb))
376 erofs_info(sb, "[deprecated] fscache-based on-demand read feature in use. Use at your own risk!");
377 out:
378 erofs_put_metabuf(&buf);
379 return ret;
380 }
381
erofs_default_options(struct erofs_sb_info * sbi)382 static void erofs_default_options(struct erofs_sb_info *sbi)
383 {
384 #ifdef CONFIG_EROFS_FS_ZIP
385 sbi->opt.cache_strategy = EROFS_ZIP_CACHE_READAROUND;
386 sbi->sync_decompress = EROFS_SYNC_DECOMPRESS_AUTO;
387 #endif
388 if (IS_ENABLED(CONFIG_EROFS_FS_XATTR))
389 set_opt(&sbi->opt, XATTR_USER);
390 if (IS_ENABLED(CONFIG_EROFS_FS_POSIX_ACL))
391 set_opt(&sbi->opt, POSIX_ACL);
392 }
393
394 enum {
395 Opt_user_xattr, Opt_acl, Opt_cache_strategy, Opt_dax, Opt_dax_enum,
396 Opt_device, Opt_fsid, Opt_domain_id, Opt_directio, Opt_fsoffset,
397 Opt_inode_share,
398 };
399
400 static const struct constant_table erofs_param_cache_strategy[] = {
401 {"disabled", EROFS_ZIP_CACHE_DISABLED},
402 {"readahead", EROFS_ZIP_CACHE_READAHEAD},
403 {"readaround", EROFS_ZIP_CACHE_READAROUND},
404 {}
405 };
406
407 static const struct constant_table erofs_dax_param_enums[] = {
408 {"always", EROFS_MOUNT_DAX_ALWAYS},
409 {"never", EROFS_MOUNT_DAX_NEVER},
410 {}
411 };
412
413 static const struct fs_parameter_spec erofs_fs_parameters[] = {
414 fsparam_flag_no("user_xattr", Opt_user_xattr),
415 fsparam_flag_no("acl", Opt_acl),
416 fsparam_enum("cache_strategy", Opt_cache_strategy,
417 erofs_param_cache_strategy),
418 fsparam_flag("dax", Opt_dax),
419 fsparam_enum("dax", Opt_dax_enum, erofs_dax_param_enums),
420 fsparam_string("device", Opt_device),
421 fsparam_string("fsid", Opt_fsid),
422 fsparam_string("domain_id", Opt_domain_id),
423 fsparam_flag_no("directio", Opt_directio),
424 fsparam_u64("fsoffset", Opt_fsoffset),
425 fsparam_flag("inode_share", Opt_inode_share),
426 {}
427 };
428
erofs_fc_set_dax_mode(struct fs_context * fc,unsigned int mode)429 static bool erofs_fc_set_dax_mode(struct fs_context *fc, unsigned int mode)
430 {
431 if (IS_ENABLED(CONFIG_FS_DAX)) {
432 struct erofs_sb_info *sbi = fc->s_fs_info;
433
434 if (mode == EROFS_MOUNT_DAX_ALWAYS) {
435 set_opt(&sbi->opt, DAX_ALWAYS);
436 clear_opt(&sbi->opt, DAX_NEVER);
437 return true;
438 } else if (mode == EROFS_MOUNT_DAX_NEVER) {
439 set_opt(&sbi->opt, DAX_NEVER);
440 clear_opt(&sbi->opt, DAX_ALWAYS);
441 return true;
442 }
443 DBG_BUGON(1);
444 return false;
445 }
446 errorfc(fc, "dax options not supported");
447 return false;
448 }
449
erofs_fc_parse_param(struct fs_context * fc,struct fs_parameter * param)450 static int erofs_fc_parse_param(struct fs_context *fc,
451 struct fs_parameter *param)
452 {
453 struct erofs_sb_info *sbi = fc->s_fs_info;
454 struct fs_parse_result result;
455 struct erofs_device_info *dif;
456 int opt, ret;
457
458 opt = fs_parse(fc, erofs_fs_parameters, param, &result);
459 if (opt < 0)
460 return opt;
461
462 switch (opt) {
463 case Opt_user_xattr:
464 if (!IS_ENABLED(CONFIG_EROFS_FS_XATTR))
465 errorfc(fc, "{,no}user_xattr options not supported");
466 else if (result.boolean)
467 set_opt(&sbi->opt, XATTR_USER);
468 else
469 clear_opt(&sbi->opt, XATTR_USER);
470 break;
471 case Opt_acl:
472 if (!IS_ENABLED(CONFIG_EROFS_FS_POSIX_ACL))
473 errorfc(fc, "{,no}acl options not supported");
474 else if (result.boolean)
475 set_opt(&sbi->opt, POSIX_ACL);
476 else
477 clear_opt(&sbi->opt, POSIX_ACL);
478 break;
479 case Opt_cache_strategy:
480 if (!IS_ENABLED(CONFIG_EROFS_FS_ZIP))
481 errorfc(fc, "compression not supported, cache_strategy ignored");
482 else
483 sbi->opt.cache_strategy = result.uint_32;
484 break;
485 case Opt_dax:
486 if (!erofs_fc_set_dax_mode(fc, EROFS_MOUNT_DAX_ALWAYS))
487 return -EINVAL;
488 break;
489 case Opt_dax_enum:
490 if (!erofs_fc_set_dax_mode(fc, result.uint_32))
491 return -EINVAL;
492 break;
493 case Opt_device:
494 dif = kzalloc_obj(*dif);
495 if (!dif)
496 return -ENOMEM;
497 dif->path = kstrdup(param->string, GFP_KERNEL);
498 if (!dif->path) {
499 kfree(dif);
500 return -ENOMEM;
501 }
502 down_write(&sbi->devs->rwsem);
503 ret = idr_alloc(&sbi->devs->tree, dif, 0, 0, GFP_KERNEL);
504 up_write(&sbi->devs->rwsem);
505 if (ret < 0) {
506 kfree(dif->path);
507 kfree(dif);
508 return ret;
509 }
510 ++sbi->devs->extra_devices;
511 break;
512 #ifdef CONFIG_EROFS_FS_ONDEMAND
513 case Opt_fsid:
514 kfree(sbi->fsid);
515 sbi->fsid = kstrdup(param->string, GFP_KERNEL);
516 if (!sbi->fsid)
517 return -ENOMEM;
518 break;
519 #endif
520 #if defined(CONFIG_EROFS_FS_ONDEMAND) || defined(CONFIG_EROFS_FS_PAGE_CACHE_SHARE)
521 case Opt_domain_id:
522 kfree_sensitive(sbi->domain_id);
523 sbi->domain_id = no_free_ptr(param->string);
524 break;
525 #else
526 case Opt_fsid:
527 case Opt_domain_id:
528 errorfc(fc, "%s option not supported", erofs_fs_parameters[opt].name);
529 break;
530 #endif
531 case Opt_directio:
532 if (!IS_ENABLED(CONFIG_EROFS_FS_BACKED_BY_FILE))
533 errorfc(fc, "%s option not supported", erofs_fs_parameters[opt].name);
534 else if (result.boolean)
535 set_opt(&sbi->opt, DIRECT_IO);
536 else
537 clear_opt(&sbi->opt, DIRECT_IO);
538 break;
539 case Opt_fsoffset:
540 sbi->dif0.fsoff = result.uint_64;
541 break;
542 case Opt_inode_share:
543 if (!IS_ENABLED(CONFIG_EROFS_FS_PAGE_CACHE_SHARE))
544 errorfc(fc, "%s option not supported", erofs_fs_parameters[opt].name);
545 else
546 set_opt(&sbi->opt, INODE_SHARE);
547 break;
548 }
549 return 0;
550 }
551
erofs_encode_fh(struct inode * inode,u32 * fh,int * max_len,struct inode * parent)552 static int erofs_encode_fh(struct inode *inode, u32 *fh, int *max_len,
553 struct inode *parent)
554 {
555 erofs_nid_t nid = EROFS_I(inode)->nid;
556 int len = parent ? 6 : 3;
557
558 if (*max_len < len) {
559 *max_len = len;
560 return FILEID_INVALID;
561 }
562
563 fh[0] = (u32)(nid >> 32);
564 fh[1] = (u32)(nid & 0xffffffff);
565 fh[2] = inode->i_generation;
566
567 if (parent) {
568 nid = EROFS_I(parent)->nid;
569
570 fh[3] = (u32)(nid >> 32);
571 fh[4] = (u32)(nid & 0xffffffff);
572 fh[5] = parent->i_generation;
573 }
574
575 *max_len = len;
576 return parent ? FILEID_INO64_GEN_PARENT : FILEID_INO64_GEN;
577 }
578
erofs_fh_to_dentry(struct super_block * sb,struct fid * fid,int fh_len,int fh_type)579 static struct dentry *erofs_fh_to_dentry(struct super_block *sb,
580 struct fid *fid, int fh_len, int fh_type)
581 {
582 if ((fh_type != FILEID_INO64_GEN &&
583 fh_type != FILEID_INO64_GEN_PARENT) || fh_len < 3)
584 return NULL;
585
586 return d_obtain_alias(erofs_iget(sb,
587 ((u64)fid->raw[0] << 32) | fid->raw[1]));
588 }
589
erofs_fh_to_parent(struct super_block * sb,struct fid * fid,int fh_len,int fh_type)590 static struct dentry *erofs_fh_to_parent(struct super_block *sb,
591 struct fid *fid, int fh_len, int fh_type)
592 {
593 if (fh_type != FILEID_INO64_GEN_PARENT || fh_len < 6)
594 return NULL;
595
596 return d_obtain_alias(erofs_iget(sb,
597 ((u64)fid->raw[3] << 32) | fid->raw[4]));
598 }
599
erofs_get_parent(struct dentry * child)600 static struct dentry *erofs_get_parent(struct dentry *child)
601 {
602 erofs_nid_t nid;
603 unsigned int d_type;
604 int err;
605
606 err = erofs_namei(d_inode(child), &dotdot_name, &nid, &d_type);
607 if (err)
608 return ERR_PTR(err);
609 return d_obtain_alias(erofs_iget(child->d_sb, nid));
610 }
611
612 static const struct export_operations erofs_export_ops = {
613 .encode_fh = erofs_encode_fh,
614 .fh_to_dentry = erofs_fh_to_dentry,
615 .fh_to_parent = erofs_fh_to_parent,
616 .get_parent = erofs_get_parent,
617 };
618
erofs_set_sysfs_name(struct super_block * sb)619 static void erofs_set_sysfs_name(struct super_block *sb)
620 {
621 struct erofs_sb_info *sbi = EROFS_SB(sb);
622
623 if (sbi->domain_id && sbi->fsid)
624 super_set_sysfs_name_generic(sb, "%s,%s", sbi->domain_id,
625 sbi->fsid);
626 else if (sbi->fsid)
627 super_set_sysfs_name_generic(sb, "%s", sbi->fsid);
628 else if (erofs_is_fileio_mode(sbi))
629 super_set_sysfs_name_generic(sb, "%s",
630 bdi_dev_name(sb->s_bdi));
631 else
632 super_set_sysfs_name_id(sb);
633 }
634
erofs_fc_fill_super(struct super_block * sb,struct fs_context * fc)635 static int erofs_fc_fill_super(struct super_block *sb, struct fs_context *fc)
636 {
637 struct inode *inode;
638 struct erofs_sb_info *sbi = EROFS_SB(sb);
639 int err;
640
641 sb->s_magic = EROFS_SUPER_MAGIC;
642 sb->s_flags |= SB_RDONLY | SB_NOATIME;
643 sb->s_maxbytes = MAX_LFS_FILESIZE;
644 sb->s_op = &erofs_sops;
645
646 if (!sbi->domain_id && test_opt(&sbi->opt, INODE_SHARE)) {
647 errorfc(fc, "domain_id is needed when inode_ishare is on");
648 return -EINVAL;
649 }
650 if (test_opt(&sbi->opt, DAX_ALWAYS) && test_opt(&sbi->opt, INODE_SHARE)) {
651 errorfc(fc, "FSDAX is not allowed when inode_ishare is on");
652 return -EINVAL;
653 }
654
655 sbi->blkszbits = PAGE_SHIFT;
656 if (!sb->s_bdev) {
657 /*
658 * (File-backed mounts) EROFS claims it's safe to nest other
659 * fs contexts (including its own) due to self-controlled RO
660 * accesses/contexts and no side-effect changes that need to
661 * context save & restore so it can reuse the current thread
662 * context.
663 * However, we still need to prevent kernel stack overflow due
664 * to filesystem nesting: just ensure that s_stack_depth is 0
665 * to disallow mounting EROFS on stacked filesystems.
666 * Note: s_stack_depth is not incremented here for now, since
667 * EROFS is the only fs supporting file-backed mounts for now.
668 * It MUST change if another fs plans to support them, which
669 * may also require adjusting FILESYSTEM_MAX_STACK_DEPTH.
670 */
671 if (erofs_is_fileio_mode(sbi)) {
672 inode = file_inode(sbi->dif0.file);
673 if ((inode->i_sb->s_op == &erofs_sops &&
674 !inode->i_sb->s_bdev) ||
675 inode->i_sb->s_stack_depth) {
676 erofs_err(sb, "file-backed mounts cannot be applied to stacked fses");
677 return -ENOTBLK;
678 }
679 }
680 sb->s_blocksize = PAGE_SIZE;
681 sb->s_blocksize_bits = PAGE_SHIFT;
682
683 if (erofs_is_fscache_mode(sb)) {
684 err = erofs_fscache_register_fs(sb);
685 if (err)
686 return err;
687 }
688 err = super_setup_bdi(sb);
689 if (err)
690 return err;
691 } else {
692 if (!sb_set_blocksize(sb, PAGE_SIZE)) {
693 errorfc(fc, "failed to set initial blksize");
694 return -EINVAL;
695 }
696
697 sbi->dif0.dax_dev = fs_dax_get_by_bdev(sb->s_bdev,
698 &sbi->dif0.dax_part_off, NULL, NULL);
699 }
700
701 err = erofs_read_superblock(sb);
702 if (err)
703 return err;
704
705 if (sb->s_blocksize_bits != sbi->blkszbits) {
706 if (erofs_is_fscache_mode(sb)) {
707 errorfc(fc, "unsupported blksize for fscache mode");
708 return -EINVAL;
709 }
710
711 if (erofs_is_fileio_mode(sbi)) {
712 sb->s_blocksize = 1 << sbi->blkszbits;
713 sb->s_blocksize_bits = sbi->blkszbits;
714 } else if (!sb_set_blocksize(sb, 1 << sbi->blkszbits)) {
715 errorfc(fc, "failed to set erofs blksize");
716 return -EINVAL;
717 }
718 }
719
720 if (sbi->dif0.fsoff) {
721 if (sbi->dif0.fsoff & (sb->s_blocksize - 1))
722 return invalfc(fc, "fsoffset %llu is not aligned to block size %lu",
723 sbi->dif0.fsoff, sb->s_blocksize);
724 if (erofs_is_fscache_mode(sb))
725 return invalfc(fc, "cannot use fsoffset in fscache mode");
726 }
727
728 if (test_opt(&sbi->opt, DAX_ALWAYS) && sbi->blkszbits != PAGE_SHIFT) {
729 erofs_info(sb, "unsupported blocksize for DAX");
730 clear_opt(&sbi->opt, DAX_ALWAYS);
731 }
732 if (test_opt(&sbi->opt, INODE_SHARE) && !erofs_sb_has_ishare_xattrs(sbi)) {
733 erofs_info(sb, "on-disk ishare xattrs not found. Turning off inode_share.");
734 clear_opt(&sbi->opt, INODE_SHARE);
735 }
736 if (test_opt(&sbi->opt, INODE_SHARE))
737 erofs_info(sb, "EXPERIMENTAL EROFS page cache share support in use. Use at your own risk!");
738
739 sb->s_time_gran = 1;
740 sb->s_xattr = erofs_xattr_handlers;
741 sb->s_export_op = &erofs_export_ops;
742
743 if (test_opt(&sbi->opt, POSIX_ACL))
744 sb->s_flags |= SB_POSIXACL;
745 else
746 sb->s_flags &= ~SB_POSIXACL;
747
748 err = z_erofs_init_super(sb);
749 if (err)
750 return err;
751
752 if (erofs_sb_has_fragments(sbi) && sbi->packed_nid) {
753 inode = erofs_iget(sb, sbi->packed_nid);
754 if (IS_ERR(inode))
755 return PTR_ERR(inode);
756 sbi->packed_inode = inode;
757 }
758 if (erofs_sb_has_metabox(sbi)) {
759 inode = erofs_iget(sb, sbi->metabox_nid);
760 if (IS_ERR(inode))
761 return PTR_ERR(inode);
762 sbi->metabox_inode = inode;
763 }
764
765 inode = erofs_iget(sb, sbi->root_nid);
766 if (IS_ERR(inode))
767 return PTR_ERR(inode);
768
769 if (!S_ISDIR(inode->i_mode)) {
770 erofs_err(sb, "rootino(nid %llu) is not a directory(i_mode %o)",
771 sbi->root_nid, inode->i_mode);
772 iput(inode);
773 return -EINVAL;
774 }
775 sb->s_root = d_make_root(inode);
776 if (!sb->s_root)
777 return -ENOMEM;
778
779 erofs_shrinker_register(sb);
780 err = erofs_xattr_prefixes_init(sb);
781 if (err)
782 return err;
783
784 erofs_set_sysfs_name(sb);
785 err = erofs_register_sysfs(sb);
786 if (err)
787 return err;
788
789 sbi->dir_ra_bytes = EROFS_DIR_RA_BYTES;
790 erofs_info(sb, "mounted with root inode @ nid %llu.", sbi->root_nid);
791 return 0;
792 }
793
erofs_fc_get_tree(struct fs_context * fc)794 static int erofs_fc_get_tree(struct fs_context *fc)
795 {
796 struct erofs_sb_info *sbi = fc->s_fs_info;
797 int ret;
798
799 if (IS_ENABLED(CONFIG_EROFS_FS_ONDEMAND) && sbi->fsid)
800 return get_tree_nodev(fc, erofs_fc_fill_super);
801
802 ret = get_tree_bdev_flags(fc, erofs_fc_fill_super,
803 IS_ENABLED(CONFIG_EROFS_FS_BACKED_BY_FILE) ?
804 GET_TREE_BDEV_QUIET_LOOKUP : 0);
805 if (IS_ENABLED(CONFIG_EROFS_FS_BACKED_BY_FILE) && ret == -ENOTBLK) {
806 struct file *file;
807
808 if (!fc->source)
809 return invalf(fc, "No source specified");
810 file = filp_open(fc->source, O_RDONLY | O_LARGEFILE, 0);
811 if (IS_ERR(file))
812 return PTR_ERR(file);
813 sbi->dif0.file = file;
814
815 if (S_ISREG(file_inode(sbi->dif0.file)->i_mode) &&
816 sbi->dif0.file->f_mapping->a_ops->read_folio)
817 return get_tree_nodev(fc, erofs_fc_fill_super);
818 }
819 return ret;
820 }
821
erofs_fc_reconfigure(struct fs_context * fc)822 static int erofs_fc_reconfigure(struct fs_context *fc)
823 {
824 struct super_block *sb = fc->root->d_sb;
825 struct erofs_sb_info *sbi = EROFS_SB(sb);
826 struct erofs_sb_info *new_sbi = fc->s_fs_info;
827
828 DBG_BUGON(!sb_rdonly(sb));
829
830 if (new_sbi->fsid || new_sbi->domain_id)
831 erofs_info(sb, "ignoring reconfiguration for fsid|domain_id.");
832
833 if (test_opt(&new_sbi->opt, POSIX_ACL))
834 fc->sb_flags |= SB_POSIXACL;
835 else
836 fc->sb_flags &= ~SB_POSIXACL;
837
838 sbi->opt = new_sbi->opt;
839
840 fc->sb_flags |= SB_RDONLY;
841 return 0;
842 }
843
erofs_release_device_info(int id,void * ptr,void * data)844 static int erofs_release_device_info(int id, void *ptr, void *data)
845 {
846 struct erofs_device_info *dif = ptr;
847
848 fs_put_dax(dif->dax_dev, NULL);
849 if (dif->file)
850 fput(dif->file);
851 erofs_fscache_unregister_cookie(dif->fscache);
852 dif->fscache = NULL;
853 kfree(dif->path);
854 kfree(dif);
855 return 0;
856 }
857
erofs_free_dev_context(struct erofs_dev_context * devs)858 static void erofs_free_dev_context(struct erofs_dev_context *devs)
859 {
860 if (!devs)
861 return;
862 idr_for_each(&devs->tree, &erofs_release_device_info, NULL);
863 idr_destroy(&devs->tree);
864 kfree(devs);
865 }
866
erofs_sb_free(struct erofs_sb_info * sbi)867 static void erofs_sb_free(struct erofs_sb_info *sbi)
868 {
869 erofs_free_dev_context(sbi->devs);
870 kfree(sbi->fsid);
871 kfree_sensitive(sbi->domain_id);
872 if (sbi->dif0.file)
873 fput(sbi->dif0.file);
874 kfree(sbi->volume_name);
875 kfree(sbi);
876 }
877
erofs_fc_free(struct fs_context * fc)878 static void erofs_fc_free(struct fs_context *fc)
879 {
880 struct erofs_sb_info *sbi = fc->s_fs_info;
881
882 if (sbi) /* free here if an error occurs before transferring to sb */
883 erofs_sb_free(sbi);
884 }
885
886 static const struct fs_context_operations erofs_context_ops = {
887 .parse_param = erofs_fc_parse_param,
888 .get_tree = erofs_fc_get_tree,
889 .reconfigure = erofs_fc_reconfigure,
890 .free = erofs_fc_free,
891 };
892
erofs_init_fs_context(struct fs_context * fc)893 static int erofs_init_fs_context(struct fs_context *fc)
894 {
895 struct erofs_sb_info *sbi;
896
897 sbi = kzalloc_obj(*sbi);
898 if (!sbi)
899 return -ENOMEM;
900
901 sbi->devs = kzalloc_obj(struct erofs_dev_context);
902 if (!sbi->devs) {
903 kfree(sbi);
904 return -ENOMEM;
905 }
906 fc->s_fs_info = sbi;
907
908 idr_init(&sbi->devs->tree);
909 init_rwsem(&sbi->devs->rwsem);
910 erofs_default_options(sbi);
911 fc->ops = &erofs_context_ops;
912 return 0;
913 }
914
erofs_drop_internal_inodes(struct erofs_sb_info * sbi)915 static void erofs_drop_internal_inodes(struct erofs_sb_info *sbi)
916 {
917 iput(sbi->packed_inode);
918 sbi->packed_inode = NULL;
919 iput(sbi->metabox_inode);
920 sbi->metabox_inode = NULL;
921 #ifdef CONFIG_EROFS_FS_ZIP
922 iput(sbi->managed_cache);
923 sbi->managed_cache = NULL;
924 #endif
925 }
926
erofs_kill_sb(struct super_block * sb)927 static void erofs_kill_sb(struct super_block *sb)
928 {
929 struct erofs_sb_info *sbi = EROFS_SB(sb);
930
931 if ((IS_ENABLED(CONFIG_EROFS_FS_ONDEMAND) && sbi->fsid) ||
932 sbi->dif0.file)
933 kill_anon_super(sb);
934 else
935 kill_block_super(sb);
936 erofs_drop_internal_inodes(sbi);
937 fs_put_dax(sbi->dif0.dax_dev, NULL);
938 erofs_fscache_unregister_fs(sb);
939 erofs_sb_free(sbi);
940 sb->s_fs_info = NULL;
941 }
942
erofs_put_super(struct super_block * sb)943 static void erofs_put_super(struct super_block *sb)
944 {
945 struct erofs_sb_info *const sbi = EROFS_SB(sb);
946
947 erofs_unregister_sysfs(sb);
948 erofs_shrinker_unregister(sb);
949 erofs_xattr_prefixes_cleanup(sb);
950 erofs_drop_internal_inodes(sbi);
951 erofs_free_dev_context(sbi->devs);
952 sbi->devs = NULL;
953 erofs_fscache_unregister_fs(sb);
954 }
955
956 static struct file_system_type erofs_fs_type = {
957 .owner = THIS_MODULE,
958 .name = "erofs",
959 .init_fs_context = erofs_init_fs_context,
960 .kill_sb = erofs_kill_sb,
961 .fs_flags = FS_REQUIRES_DEV | FS_ALLOW_IDMAP,
962 };
963 MODULE_ALIAS_FS("erofs");
964
965 #if defined(CONFIG_EROFS_FS_ONDEMAND) || defined(CONFIG_EROFS_FS_PAGE_CACHE_SHARE)
erofs_free_anon_inode(struct inode * inode)966 static void erofs_free_anon_inode(struct inode *inode)
967 {
968 struct erofs_inode *vi = EROFS_I(inode);
969
970 #ifdef CONFIG_EROFS_FS_PAGE_CACHE_SHARE
971 kfree(vi->fingerprint.opaque);
972 #endif
973 kmem_cache_free(erofs_inode_cachep, vi);
974 }
975
976 static const struct super_operations erofs_anon_sops = {
977 .alloc_inode = erofs_alloc_inode,
978 .drop_inode = inode_just_drop,
979 .free_inode = erofs_free_anon_inode,
980 };
981
erofs_anon_init_fs_context(struct fs_context * fc)982 static int erofs_anon_init_fs_context(struct fs_context *fc)
983 {
984 struct pseudo_fs_context *ctx;
985
986 ctx = init_pseudo(fc, EROFS_SUPER_MAGIC);
987 if (!ctx)
988 return -ENOMEM;
989 ctx->ops = &erofs_anon_sops;
990 return 0;
991 }
992
993 struct file_system_type erofs_anon_fs_type = {
994 .name = "pseudo_erofs",
995 .init_fs_context = erofs_anon_init_fs_context,
996 .kill_sb = kill_anon_super,
997 };
998 #endif
999
erofs_module_init(void)1000 static int __init erofs_module_init(void)
1001 {
1002 int err;
1003
1004 erofs_check_ondisk_layout_definitions();
1005
1006 erofs_inode_cachep = kmem_cache_create("erofs_inode",
1007 sizeof(struct erofs_inode), 0,
1008 SLAB_RECLAIM_ACCOUNT | SLAB_ACCOUNT,
1009 erofs_inode_init_once);
1010 if (!erofs_inode_cachep)
1011 return -ENOMEM;
1012
1013 err = erofs_init_shrinker();
1014 if (err)
1015 goto shrinker_err;
1016
1017 err = z_erofs_init_subsystem();
1018 if (err)
1019 goto zip_err;
1020
1021 err = erofs_init_sysfs();
1022 if (err)
1023 goto sysfs_err;
1024
1025 err = erofs_init_ishare();
1026 if (err)
1027 goto ishare_err;
1028
1029 err = register_filesystem(&erofs_fs_type);
1030 if (err)
1031 goto fs_err;
1032
1033 return 0;
1034
1035 fs_err:
1036 erofs_exit_ishare();
1037 ishare_err:
1038 erofs_exit_sysfs();
1039 sysfs_err:
1040 z_erofs_exit_subsystem();
1041 zip_err:
1042 erofs_exit_shrinker();
1043 shrinker_err:
1044 kmem_cache_destroy(erofs_inode_cachep);
1045 return err;
1046 }
1047
erofs_module_exit(void)1048 static void __exit erofs_module_exit(void)
1049 {
1050 unregister_filesystem(&erofs_fs_type);
1051
1052 /* Ensure all RCU free inodes / pclusters are safe to be destroyed. */
1053 rcu_barrier();
1054
1055 erofs_exit_ishare();
1056 erofs_exit_sysfs();
1057 z_erofs_exit_subsystem();
1058 erofs_exit_shrinker();
1059 kmem_cache_destroy(erofs_inode_cachep);
1060 }
1061
erofs_statfs(struct dentry * dentry,struct kstatfs * buf)1062 static int erofs_statfs(struct dentry *dentry, struct kstatfs *buf)
1063 {
1064 struct super_block *sb = dentry->d_sb;
1065 struct erofs_sb_info *sbi = EROFS_SB(sb);
1066
1067 buf->f_type = sb->s_magic;
1068 buf->f_bsize = sb->s_blocksize;
1069 buf->f_blocks = sbi->total_blocks;
1070 buf->f_bfree = buf->f_bavail = 0;
1071 buf->f_files = ULLONG_MAX;
1072 buf->f_ffree = ULLONG_MAX - sbi->inos;
1073 buf->f_namelen = EROFS_NAME_LEN;
1074
1075 if (uuid_is_null(&sb->s_uuid))
1076 buf->f_fsid = u64_to_fsid(!sb->s_bdev ? 0 :
1077 huge_encode_dev(sb->s_bdev->bd_dev));
1078 else
1079 buf->f_fsid = uuid_to_fsid(sb->s_uuid.b);
1080 return 0;
1081 }
1082
erofs_show_options(struct seq_file * seq,struct dentry * root)1083 static int erofs_show_options(struct seq_file *seq, struct dentry *root)
1084 {
1085 struct erofs_sb_info *sbi = EROFS_SB(root->d_sb);
1086 struct erofs_mount_opts *opt = &sbi->opt;
1087
1088 if (IS_ENABLED(CONFIG_EROFS_FS_XATTR))
1089 seq_puts(seq, test_opt(opt, XATTR_USER) ?
1090 ",user_xattr" : ",nouser_xattr");
1091 if (IS_ENABLED(CONFIG_EROFS_FS_POSIX_ACL))
1092 seq_puts(seq, test_opt(opt, POSIX_ACL) ? ",acl" : ",noacl");
1093 if (IS_ENABLED(CONFIG_EROFS_FS_ZIP))
1094 seq_printf(seq, ",cache_strategy=%s",
1095 erofs_param_cache_strategy[opt->cache_strategy].name);
1096 if (test_opt(opt, DAX_ALWAYS))
1097 seq_puts(seq, ",dax=always");
1098 if (test_opt(opt, DAX_NEVER))
1099 seq_puts(seq, ",dax=never");
1100 if (erofs_is_fileio_mode(sbi) && test_opt(opt, DIRECT_IO))
1101 seq_puts(seq, ",directio");
1102 if (IS_ENABLED(CONFIG_EROFS_FS_ONDEMAND)) {
1103 if (sbi->fsid)
1104 seq_printf(seq, ",fsid=%s", sbi->fsid);
1105 if (sbi->domain_id)
1106 seq_printf(seq, ",domain_id=%s", sbi->domain_id);
1107 }
1108 if (sbi->dif0.fsoff)
1109 seq_printf(seq, ",fsoffset=%llu", sbi->dif0.fsoff);
1110 if (test_opt(opt, INODE_SHARE))
1111 seq_puts(seq, ",inode_share");
1112 return 0;
1113 }
1114
erofs_evict_inode(struct inode * inode)1115 static void erofs_evict_inode(struct inode *inode)
1116 {
1117 if (IS_DAX(inode))
1118 dax_break_layout_final(inode);
1119 erofs_ishare_free_inode(inode);
1120 truncate_inode_pages_final(&inode->i_data);
1121 clear_inode(inode);
1122 }
1123
1124 const struct super_operations erofs_sops = {
1125 .put_super = erofs_put_super,
1126 .alloc_inode = erofs_alloc_inode,
1127 .free_inode = erofs_free_inode,
1128 .evict_inode = erofs_evict_inode,
1129 .statfs = erofs_statfs,
1130 .show_options = erofs_show_options,
1131 };
1132
1133 module_init(erofs_module_init);
1134 module_exit(erofs_module_exit);
1135
1136 MODULE_DESCRIPTION("Enhanced ROM File System");
1137 MODULE_AUTHOR("Gao Xiang, Chao Yu, Miao Xie, CONSUMER BG, HUAWEI Inc.");
1138 MODULE_LICENSE("GPL");
1139