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
133 dis = erofs_read_metabuf(buf, sb, *pos, false);
134 if (IS_ERR(dis))
135 return PTR_ERR(dis);
136
137 if (!sbi->devs->flatdev && !dif->path) {
138 if (!dis->tag[0]) {
139 erofs_err(sb, "empty device tag @ pos %llu", *pos);
140 return -EINVAL;
141 }
142 dif->path = kmemdup_nul(dis->tag, sizeof(dis->tag), GFP_KERNEL);
143 if (!dif->path)
144 return -ENOMEM;
145 }
146
147 if (erofs_is_fscache_mode(sb)) {
148 fscache = erofs_fscache_register_cookie(sb, dif->path, 0);
149 if (IS_ERR(fscache))
150 return PTR_ERR(fscache);
151 dif->fscache = fscache;
152 } else if (!sbi->devs->flatdev) {
153 file = erofs_is_fileio_mode(sbi) ?
154 filp_open(dif->path, O_RDONLY | O_LARGEFILE, 0) :
155 bdev_file_open_by_path(dif->path,
156 BLK_OPEN_READ, sb->s_type, NULL);
157 if (IS_ERR(file)) {
158 if (file == ERR_PTR(-ENOTBLK))
159 return -EINVAL;
160 return PTR_ERR(file);
161 }
162
163 if (!erofs_is_fileio_mode(sbi)) {
164 dif->dax_dev = fs_dax_get_by_bdev(file_bdev(file),
165 &dif->dax_part_off, NULL, NULL);
166 } else if (!S_ISREG(file_inode(file)->i_mode)) {
167 fput(file);
168 return -EINVAL;
169 }
170 if (!dif->dax_dev && test_opt(&sbi->opt, DAX_ALWAYS)) {
171 erofs_info(sb, "DAX unsupported by %s. Turning off DAX.",
172 dif->path);
173 clear_opt(&sbi->opt, DAX_ALWAYS);
174 }
175 dif->file = file;
176 }
177
178 dif->blocks = le32_to_cpu(dis->blocks_lo);
179 dif->uniaddr = le32_to_cpu(dis->uniaddr_lo);
180 sbi->total_blocks += dif->blocks;
181 *pos += EROFS_DEVT_SLOT_SIZE;
182 return 0;
183 }
184
erofs_scan_devices(struct super_block * sb,struct erofs_super_block * dsb)185 static int erofs_scan_devices(struct super_block *sb,
186 struct erofs_super_block *dsb)
187 {
188 struct erofs_sb_info *sbi = EROFS_SB(sb);
189 unsigned int ondisk_extradevs;
190 erofs_off_t pos;
191 struct erofs_buf buf = __EROFS_BUF_INITIALIZER;
192 struct erofs_device_info *dif;
193 int id, err = 0;
194
195 sbi->total_blocks = sbi->dif0.blocks;
196 if (!erofs_sb_has_device_table(sbi))
197 ondisk_extradevs = 0;
198 else
199 ondisk_extradevs = le16_to_cpu(dsb->extra_devices);
200
201 if (sbi->devs->extra_devices &&
202 ondisk_extradevs != sbi->devs->extra_devices) {
203 erofs_err(sb, "extra devices don't match (ondisk %u, given %u)",
204 ondisk_extradevs, sbi->devs->extra_devices);
205 return -EINVAL;
206 }
207
208 if (test_opt(&sbi->opt, DAX_ALWAYS) && !sbi->dif0.dax_dev) {
209 erofs_info(sb, "DAX unsupported by block device. Turning off DAX.");
210 clear_opt(&sbi->opt, DAX_ALWAYS);
211 }
212 if (!ondisk_extradevs)
213 return 0;
214
215 if (!sbi->devs->extra_devices && !erofs_is_fscache_mode(sb))
216 sbi->devs->flatdev = true;
217
218 sbi->device_id_mask = roundup_pow_of_two(ondisk_extradevs + 1) - 1;
219 pos = le16_to_cpu(dsb->devt_slotoff) * EROFS_DEVT_SLOT_SIZE;
220 down_read(&sbi->devs->rwsem);
221 if (sbi->devs->extra_devices) {
222 idr_for_each_entry(&sbi->devs->tree, dif, id) {
223 err = erofs_init_device(&buf, sb, dif, &pos);
224 if (err)
225 break;
226 }
227 } else {
228 for (id = 0; id < ondisk_extradevs; id++) {
229 dif = kzalloc_obj(*dif);
230 if (!dif) {
231 err = -ENOMEM;
232 break;
233 }
234
235 err = idr_alloc(&sbi->devs->tree, dif, 0, 0, GFP_KERNEL);
236 if (err < 0) {
237 kfree(dif);
238 break;
239 }
240 ++sbi->devs->extra_devices;
241
242 err = erofs_init_device(&buf, sb, dif, &pos);
243 if (err)
244 break;
245 }
246 }
247 up_read(&sbi->devs->rwsem);
248 erofs_put_metabuf(&buf);
249 return err;
250 }
251
erofs_read_superblock(struct super_block * sb)252 static int erofs_read_superblock(struct super_block *sb)
253 {
254 struct erofs_sb_info *sbi = EROFS_SB(sb);
255 struct erofs_buf buf = __EROFS_BUF_INITIALIZER;
256 struct erofs_super_block *dsb;
257 void *data;
258 int ret;
259
260 data = erofs_read_metabuf(&buf, sb, 0, false);
261 if (IS_ERR(data)) {
262 erofs_err(sb, "cannot read erofs superblock");
263 return PTR_ERR(data);
264 }
265
266 dsb = (struct erofs_super_block *)(data + EROFS_SUPER_OFFSET);
267 ret = -EINVAL;
268 if (le32_to_cpu(dsb->magic) != EROFS_SUPER_MAGIC_V1) {
269 erofs_err(sb, "cannot find valid erofs superblock");
270 goto out;
271 }
272
273 sbi->blkszbits = dsb->blkszbits;
274 if (sbi->blkszbits < 9 || sbi->blkszbits > PAGE_SHIFT) {
275 erofs_err(sb, "blkszbits %u isn't supported", sbi->blkszbits);
276 goto out;
277 }
278 if (dsb->dirblkbits) {
279 erofs_err(sb, "dirblkbits %u isn't supported", dsb->dirblkbits);
280 goto out;
281 }
282
283 sbi->feature_compat = le32_to_cpu(dsb->feature_compat);
284 if (erofs_sb_has_sb_chksum(sbi)) {
285 ret = erofs_superblock_csum_verify(sb, data);
286 if (ret)
287 goto out;
288 }
289
290 ret = -EINVAL;
291 sbi->feature_incompat = le32_to_cpu(dsb->feature_incompat);
292 if (sbi->feature_incompat & ~EROFS_ALL_FEATURE_INCOMPAT) {
293 erofs_err(sb, "unidentified incompatible feature %x, please upgrade kernel",
294 sbi->feature_incompat & ~EROFS_ALL_FEATURE_INCOMPAT);
295 goto out;
296 }
297
298 sbi->sb_size = 128 + dsb->sb_extslots * EROFS_SB_EXTSLOT_SIZE;
299 if (sbi->sb_size > PAGE_SIZE - EROFS_SUPER_OFFSET) {
300 erofs_err(sb, "invalid sb_extslots %u (more than a fs block)",
301 sbi->sb_size);
302 goto out;
303 }
304 sbi->dif0.blocks = le32_to_cpu(dsb->blocks_lo);
305 sbi->meta_blkaddr = le32_to_cpu(dsb->meta_blkaddr);
306 #ifdef CONFIG_EROFS_FS_XATTR
307 sbi->xattr_blkaddr = le32_to_cpu(dsb->xattr_blkaddr);
308 sbi->xattr_prefix_start = le32_to_cpu(dsb->xattr_prefix_start);
309 sbi->xattr_prefix_count = dsb->xattr_prefix_count;
310 sbi->xattr_filter_reserved = dsb->xattr_filter_reserved;
311 if (erofs_sb_has_ishare_xattrs(sbi)) {
312 if (dsb->ishare_xattr_prefix_id >= sbi->xattr_prefix_count) {
313 erofs_err(sb, "invalid ishare xattr prefix id %u",
314 dsb->ishare_xattr_prefix_id);
315 ret = -EFSCORRUPTED;
316 goto out;
317 }
318 sbi->ishare_xattr_prefix_id = dsb->ishare_xattr_prefix_id;
319 }
320 #endif
321 sbi->islotbits = ilog2(sizeof(struct erofs_inode_compact));
322 if (erofs_sb_has_48bit(sbi) && dsb->rootnid_8b) {
323 sbi->root_nid = le64_to_cpu(dsb->rootnid_8b);
324 sbi->dif0.blocks = sbi->dif0.blocks |
325 ((u64)le16_to_cpu(dsb->rb.blocks_hi) << 32);
326 } else {
327 sbi->root_nid = le16_to_cpu(dsb->rb.rootnid_2b);
328 }
329 sbi->packed_nid = le64_to_cpu(dsb->packed_nid);
330 if (erofs_sb_has_metabox(sbi)) {
331 ret = -EFSCORRUPTED;
332 if (sbi->sb_size <= offsetof(struct erofs_super_block,
333 metabox_nid))
334 goto out;
335 sbi->metabox_nid = le64_to_cpu(dsb->metabox_nid);
336 if (sbi->metabox_nid & BIT_ULL(EROFS_DIRENT_NID_METABOX_BIT))
337 goto out; /* self-loop detection */
338 }
339 sbi->inos = le64_to_cpu(dsb->inos);
340
341 sbi->epoch = (s64)le64_to_cpu(dsb->epoch);
342 sbi->fixed_nsec = le32_to_cpu(dsb->fixed_nsec);
343 super_set_uuid(sb, (void *)dsb->uuid, sizeof(dsb->uuid));
344
345 if (dsb->volume_name[0]) {
346 sbi->volume_name = kstrndup(dsb->volume_name,
347 sizeof(dsb->volume_name), GFP_KERNEL);
348 if (!sbi->volume_name) {
349 ret = -ENOMEM;
350 goto out;
351 }
352 }
353
354 if (IS_ENABLED(CONFIG_EROFS_FS_ZIP)) {
355 ret = z_erofs_parse_cfgs(sb, dsb);
356 if (ret < 0)
357 goto out;
358 } else if (dsb->u1.available_compr_algs ||
359 erofs_sb_has_lz4_0padding(sbi)) {
360 erofs_err(sb, "compression disabled, unable to mount compressed EROFS");
361 ret = -EOPNOTSUPP;
362 goto out;
363 }
364
365 ret = erofs_scan_devices(sb, dsb);
366
367 if (erofs_sb_has_48bit(sbi))
368 erofs_info(sb, "EXPERIMENTAL 48-bit layout support in use. Use at your own risk!");
369 if (erofs_sb_has_metabox(sbi))
370 erofs_info(sb, "EXPERIMENTAL metadata compression support in use. Use at your own risk!");
371 if (erofs_is_fscache_mode(sb))
372 erofs_info(sb, "[deprecated] fscache-based on-demand read feature in use. Use at your own risk!");
373 out:
374 erofs_put_metabuf(&buf);
375 return ret;
376 }
377
erofs_default_options(struct erofs_sb_info * sbi)378 static void erofs_default_options(struct erofs_sb_info *sbi)
379 {
380 #ifdef CONFIG_EROFS_FS_ZIP
381 sbi->opt.cache_strategy = EROFS_ZIP_CACHE_READAROUND;
382 sbi->sync_decompress = EROFS_SYNC_DECOMPRESS_AUTO;
383 #endif
384 if (IS_ENABLED(CONFIG_EROFS_FS_XATTR))
385 set_opt(&sbi->opt, XATTR_USER);
386 if (IS_ENABLED(CONFIG_EROFS_FS_POSIX_ACL))
387 set_opt(&sbi->opt, POSIX_ACL);
388 }
389
390 enum {
391 Opt_user_xattr, Opt_acl, Opt_cache_strategy, Opt_dax, Opt_dax_enum,
392 Opt_device, Opt_fsid, Opt_domain_id, Opt_directio, Opt_fsoffset,
393 Opt_inode_share,
394 };
395
396 static const struct constant_table erofs_param_cache_strategy[] = {
397 {"disabled", EROFS_ZIP_CACHE_DISABLED},
398 {"readahead", EROFS_ZIP_CACHE_READAHEAD},
399 {"readaround", EROFS_ZIP_CACHE_READAROUND},
400 {}
401 };
402
403 static const struct constant_table erofs_dax_param_enums[] = {
404 {"always", EROFS_MOUNT_DAX_ALWAYS},
405 {"never", EROFS_MOUNT_DAX_NEVER},
406 {}
407 };
408
409 static const struct fs_parameter_spec erofs_fs_parameters[] = {
410 fsparam_flag_no("user_xattr", Opt_user_xattr),
411 fsparam_flag_no("acl", Opt_acl),
412 fsparam_enum("cache_strategy", Opt_cache_strategy,
413 erofs_param_cache_strategy),
414 fsparam_flag("dax", Opt_dax),
415 fsparam_enum("dax", Opt_dax_enum, erofs_dax_param_enums),
416 fsparam_string("device", Opt_device),
417 fsparam_string("fsid", Opt_fsid),
418 fsparam_string("domain_id", Opt_domain_id),
419 fsparam_flag_no("directio", Opt_directio),
420 fsparam_u64("fsoffset", Opt_fsoffset),
421 fsparam_flag("inode_share", Opt_inode_share),
422 {}
423 };
424
erofs_fc_set_dax_mode(struct fs_context * fc,unsigned int mode)425 static bool erofs_fc_set_dax_mode(struct fs_context *fc, unsigned int mode)
426 {
427 #ifdef CONFIG_FS_DAX
428 struct erofs_sb_info *sbi = fc->s_fs_info;
429
430 switch (mode) {
431 case EROFS_MOUNT_DAX_ALWAYS:
432 set_opt(&sbi->opt, DAX_ALWAYS);
433 clear_opt(&sbi->opt, DAX_NEVER);
434 return true;
435 case EROFS_MOUNT_DAX_NEVER:
436 set_opt(&sbi->opt, DAX_NEVER);
437 clear_opt(&sbi->opt, DAX_ALWAYS);
438 return true;
439 default:
440 DBG_BUGON(1);
441 return false;
442 }
443 #else
444 errorfc(fc, "dax options not supported");
445 return false;
446 #endif
447 }
448
erofs_fc_parse_param(struct fs_context * fc,struct fs_parameter * param)449 static int erofs_fc_parse_param(struct fs_context *fc,
450 struct fs_parameter *param)
451 {
452 struct erofs_sb_info *sbi = fc->s_fs_info;
453 struct fs_parse_result result;
454 struct erofs_device_info *dif;
455 int opt, ret;
456
457 opt = fs_parse(fc, erofs_fs_parameters, param, &result);
458 if (opt < 0)
459 return opt;
460
461 switch (opt) {
462 case Opt_user_xattr:
463 #ifdef CONFIG_EROFS_FS_XATTR
464 if (result.boolean)
465 set_opt(&sbi->opt, XATTR_USER);
466 else
467 clear_opt(&sbi->opt, XATTR_USER);
468 #else
469 errorfc(fc, "{,no}user_xattr options not supported");
470 #endif
471 break;
472 case Opt_acl:
473 #ifdef CONFIG_EROFS_FS_POSIX_ACL
474 if (result.boolean)
475 set_opt(&sbi->opt, POSIX_ACL);
476 else
477 clear_opt(&sbi->opt, POSIX_ACL);
478 #else
479 errorfc(fc, "{,no}acl options not supported");
480 #endif
481 break;
482 case Opt_cache_strategy:
483 #ifdef CONFIG_EROFS_FS_ZIP
484 sbi->opt.cache_strategy = result.uint_32;
485 #else
486 errorfc(fc, "compression not supported, cache_strategy ignored");
487 #endif
488 break;
489 case Opt_dax:
490 if (!erofs_fc_set_dax_mode(fc, EROFS_MOUNT_DAX_ALWAYS))
491 return -EINVAL;
492 break;
493 case Opt_dax_enum:
494 if (!erofs_fc_set_dax_mode(fc, result.uint_32))
495 return -EINVAL;
496 break;
497 case Opt_device:
498 dif = kzalloc_obj(*dif);
499 if (!dif)
500 return -ENOMEM;
501 dif->path = kstrdup(param->string, GFP_KERNEL);
502 if (!dif->path) {
503 kfree(dif);
504 return -ENOMEM;
505 }
506 down_write(&sbi->devs->rwsem);
507 ret = idr_alloc(&sbi->devs->tree, dif, 0, 0, GFP_KERNEL);
508 up_write(&sbi->devs->rwsem);
509 if (ret < 0) {
510 kfree(dif->path);
511 kfree(dif);
512 return ret;
513 }
514 ++sbi->devs->extra_devices;
515 break;
516 #ifdef CONFIG_EROFS_FS_ONDEMAND
517 case Opt_fsid:
518 kfree(sbi->fsid);
519 sbi->fsid = kstrdup(param->string, GFP_KERNEL);
520 if (!sbi->fsid)
521 return -ENOMEM;
522 break;
523 #endif
524 #if defined(CONFIG_EROFS_FS_ONDEMAND) || defined(CONFIG_EROFS_FS_PAGE_CACHE_SHARE)
525 case Opt_domain_id:
526 kfree_sensitive(sbi->domain_id);
527 sbi->domain_id = no_free_ptr(param->string);
528 break;
529 #else
530 case Opt_fsid:
531 case Opt_domain_id:
532 errorfc(fc, "%s option not supported", erofs_fs_parameters[opt].name);
533 break;
534 #endif
535 case Opt_directio:
536 #ifdef CONFIG_EROFS_FS_BACKED_BY_FILE
537 if (result.boolean)
538 set_opt(&sbi->opt, DIRECT_IO);
539 else
540 clear_opt(&sbi->opt, DIRECT_IO);
541 #else
542 errorfc(fc, "%s option not supported", erofs_fs_parameters[opt].name);
543 #endif
544 break;
545 case Opt_fsoffset:
546 sbi->dif0.fsoff = result.uint_64;
547 break;
548 case Opt_inode_share:
549 #ifdef CONFIG_EROFS_FS_PAGE_CACHE_SHARE
550 set_opt(&sbi->opt, INODE_SHARE);
551 #else
552 errorfc(fc, "%s option not supported", erofs_fs_parameters[opt].name);
553 #endif
554 break;
555 }
556 return 0;
557 }
558
erofs_encode_fh(struct inode * inode,u32 * fh,int * max_len,struct inode * parent)559 static int erofs_encode_fh(struct inode *inode, u32 *fh, int *max_len,
560 struct inode *parent)
561 {
562 erofs_nid_t nid = EROFS_I(inode)->nid;
563 int len = parent ? 6 : 3;
564
565 if (*max_len < len) {
566 *max_len = len;
567 return FILEID_INVALID;
568 }
569
570 fh[0] = (u32)(nid >> 32);
571 fh[1] = (u32)(nid & 0xffffffff);
572 fh[2] = inode->i_generation;
573
574 if (parent) {
575 nid = EROFS_I(parent)->nid;
576
577 fh[3] = (u32)(nid >> 32);
578 fh[4] = (u32)(nid & 0xffffffff);
579 fh[5] = parent->i_generation;
580 }
581
582 *max_len = len;
583 return parent ? FILEID_INO64_GEN_PARENT : FILEID_INO64_GEN;
584 }
585
erofs_fh_to_dentry(struct super_block * sb,struct fid * fid,int fh_len,int fh_type)586 static struct dentry *erofs_fh_to_dentry(struct super_block *sb,
587 struct fid *fid, int fh_len, int fh_type)
588 {
589 if ((fh_type != FILEID_INO64_GEN &&
590 fh_type != FILEID_INO64_GEN_PARENT) || fh_len < 3)
591 return NULL;
592
593 return d_obtain_alias(erofs_iget(sb,
594 ((u64)fid->raw[0] << 32) | fid->raw[1]));
595 }
596
erofs_fh_to_parent(struct super_block * sb,struct fid * fid,int fh_len,int fh_type)597 static struct dentry *erofs_fh_to_parent(struct super_block *sb,
598 struct fid *fid, int fh_len, int fh_type)
599 {
600 if (fh_type != FILEID_INO64_GEN_PARENT || fh_len < 6)
601 return NULL;
602
603 return d_obtain_alias(erofs_iget(sb,
604 ((u64)fid->raw[3] << 32) | fid->raw[4]));
605 }
606
erofs_get_parent(struct dentry * child)607 static struct dentry *erofs_get_parent(struct dentry *child)
608 {
609 erofs_nid_t nid;
610 unsigned int d_type;
611 int err;
612
613 err = erofs_namei(d_inode(child), &dotdot_name, &nid, &d_type);
614 if (err)
615 return ERR_PTR(err);
616 return d_obtain_alias(erofs_iget(child->d_sb, nid));
617 }
618
619 static const struct export_operations erofs_export_ops = {
620 .encode_fh = erofs_encode_fh,
621 .fh_to_dentry = erofs_fh_to_dentry,
622 .fh_to_parent = erofs_fh_to_parent,
623 .get_parent = erofs_get_parent,
624 };
625
erofs_set_sysfs_name(struct super_block * sb)626 static void erofs_set_sysfs_name(struct super_block *sb)
627 {
628 struct erofs_sb_info *sbi = EROFS_SB(sb);
629
630 if (sbi->domain_id && sbi->fsid)
631 super_set_sysfs_name_generic(sb, "%s,%s", sbi->domain_id,
632 sbi->fsid);
633 else if (sbi->fsid)
634 super_set_sysfs_name_generic(sb, "%s", sbi->fsid);
635 else if (erofs_is_fileio_mode(sbi))
636 super_set_sysfs_name_generic(sb, "%s",
637 bdi_dev_name(sb->s_bdi));
638 else
639 super_set_sysfs_name_id(sb);
640 }
641
erofs_fc_fill_super(struct super_block * sb,struct fs_context * fc)642 static int erofs_fc_fill_super(struct super_block *sb, struct fs_context *fc)
643 {
644 struct inode *inode;
645 struct erofs_sb_info *sbi = EROFS_SB(sb);
646 int err;
647
648 sb->s_magic = EROFS_SUPER_MAGIC;
649 sb->s_flags |= SB_RDONLY | SB_NOATIME;
650 sb->s_maxbytes = MAX_LFS_FILESIZE;
651 sb->s_op = &erofs_sops;
652
653 if (!sbi->domain_id && test_opt(&sbi->opt, INODE_SHARE)) {
654 errorfc(fc, "domain_id is needed when inode_ishare is on");
655 return -EINVAL;
656 }
657 if (test_opt(&sbi->opt, DAX_ALWAYS) && test_opt(&sbi->opt, INODE_SHARE)) {
658 errorfc(fc, "FSDAX is not allowed when inode_ishare is on");
659 return -EINVAL;
660 }
661
662 sbi->blkszbits = PAGE_SHIFT;
663 if (!sb->s_bdev) {
664 /*
665 * (File-backed mounts) EROFS claims it's safe to nest other
666 * fs contexts (including its own) due to self-controlled RO
667 * accesses/contexts and no side-effect changes that need to
668 * context save & restore so it can reuse the current thread
669 * context.
670 * However, we still need to prevent kernel stack overflow due
671 * to filesystem nesting: just ensure that s_stack_depth is 0
672 * to disallow mounting EROFS on stacked filesystems.
673 * Note: s_stack_depth is not incremented here for now, since
674 * EROFS is the only fs supporting file-backed mounts for now.
675 * It MUST change if another fs plans to support them, which
676 * may also require adjusting FILESYSTEM_MAX_STACK_DEPTH.
677 */
678 if (erofs_is_fileio_mode(sbi)) {
679 inode = file_inode(sbi->dif0.file);
680 if ((inode->i_sb->s_op == &erofs_sops &&
681 !inode->i_sb->s_bdev) ||
682 inode->i_sb->s_stack_depth) {
683 erofs_err(sb, "file-backed mounts cannot be applied to stacked fses");
684 return -ENOTBLK;
685 }
686 }
687 sb->s_blocksize = PAGE_SIZE;
688 sb->s_blocksize_bits = PAGE_SHIFT;
689
690 if (erofs_is_fscache_mode(sb)) {
691 err = erofs_fscache_register_fs(sb);
692 if (err)
693 return err;
694 }
695 err = super_setup_bdi(sb);
696 if (err)
697 return err;
698 } else {
699 if (!sb_set_blocksize(sb, PAGE_SIZE)) {
700 errorfc(fc, "failed to set initial blksize");
701 return -EINVAL;
702 }
703
704 sbi->dif0.dax_dev = fs_dax_get_by_bdev(sb->s_bdev,
705 &sbi->dif0.dax_part_off, NULL, NULL);
706 }
707
708 err = erofs_read_superblock(sb);
709 if (err)
710 return err;
711
712 if (sb->s_blocksize_bits != sbi->blkszbits) {
713 if (erofs_is_fscache_mode(sb)) {
714 errorfc(fc, "unsupported blksize for fscache mode");
715 return -EINVAL;
716 }
717
718 if (erofs_is_fileio_mode(sbi)) {
719 sb->s_blocksize = 1 << sbi->blkszbits;
720 sb->s_blocksize_bits = sbi->blkszbits;
721 } else if (!sb_set_blocksize(sb, 1 << sbi->blkszbits)) {
722 errorfc(fc, "failed to set erofs blksize");
723 return -EINVAL;
724 }
725 }
726
727 if (sbi->dif0.fsoff) {
728 if (sbi->dif0.fsoff & (sb->s_blocksize - 1))
729 return invalfc(fc, "fsoffset %llu is not aligned to block size %lu",
730 sbi->dif0.fsoff, sb->s_blocksize);
731 if (erofs_is_fscache_mode(sb))
732 return invalfc(fc, "cannot use fsoffset in fscache mode");
733 }
734
735 if (test_opt(&sbi->opt, DAX_ALWAYS) && sbi->blkszbits != PAGE_SHIFT) {
736 erofs_info(sb, "unsupported blocksize for DAX");
737 clear_opt(&sbi->opt, DAX_ALWAYS);
738 }
739 if (test_opt(&sbi->opt, INODE_SHARE) && !erofs_sb_has_ishare_xattrs(sbi)) {
740 erofs_info(sb, "on-disk ishare xattrs not found. Turning off inode_share.");
741 clear_opt(&sbi->opt, INODE_SHARE);
742 }
743 if (test_opt(&sbi->opt, INODE_SHARE))
744 erofs_info(sb, "EXPERIMENTAL EROFS page cache share support in use. Use at your own risk!");
745
746 sb->s_time_gran = 1;
747 sb->s_xattr = erofs_xattr_handlers;
748 sb->s_export_op = &erofs_export_ops;
749
750 if (test_opt(&sbi->opt, POSIX_ACL))
751 sb->s_flags |= SB_POSIXACL;
752 else
753 sb->s_flags &= ~SB_POSIXACL;
754
755 err = z_erofs_init_super(sb);
756 if (err)
757 return err;
758
759 if (erofs_sb_has_fragments(sbi) && sbi->packed_nid) {
760 inode = erofs_iget(sb, sbi->packed_nid);
761 if (IS_ERR(inode))
762 return PTR_ERR(inode);
763 sbi->packed_inode = inode;
764 }
765 if (erofs_sb_has_metabox(sbi)) {
766 inode = erofs_iget(sb, sbi->metabox_nid);
767 if (IS_ERR(inode))
768 return PTR_ERR(inode);
769 sbi->metabox_inode = inode;
770 }
771
772 inode = erofs_iget(sb, sbi->root_nid);
773 if (IS_ERR(inode))
774 return PTR_ERR(inode);
775
776 if (!S_ISDIR(inode->i_mode)) {
777 erofs_err(sb, "rootino(nid %llu) is not a directory(i_mode %o)",
778 sbi->root_nid, inode->i_mode);
779 iput(inode);
780 return -EINVAL;
781 }
782 sb->s_root = d_make_root(inode);
783 if (!sb->s_root)
784 return -ENOMEM;
785
786 erofs_shrinker_register(sb);
787 err = erofs_xattr_prefixes_init(sb);
788 if (err)
789 return err;
790
791 erofs_set_sysfs_name(sb);
792 err = erofs_register_sysfs(sb);
793 if (err)
794 return err;
795
796 sbi->dir_ra_bytes = EROFS_DIR_RA_BYTES;
797 erofs_info(sb, "mounted with root inode @ nid %llu.", sbi->root_nid);
798 return 0;
799 }
800
erofs_fc_get_tree(struct fs_context * fc)801 static int erofs_fc_get_tree(struct fs_context *fc)
802 {
803 struct erofs_sb_info *sbi = fc->s_fs_info;
804 int ret;
805
806 if (IS_ENABLED(CONFIG_EROFS_FS_ONDEMAND) && sbi->fsid)
807 return get_tree_nodev(fc, erofs_fc_fill_super);
808
809 ret = get_tree_bdev_flags(fc, erofs_fc_fill_super,
810 IS_ENABLED(CONFIG_EROFS_FS_BACKED_BY_FILE) ?
811 GET_TREE_BDEV_QUIET_LOOKUP : 0);
812 #ifdef CONFIG_EROFS_FS_BACKED_BY_FILE
813 if (ret == -ENOTBLK) {
814 struct file *file;
815
816 if (!fc->source)
817 return invalf(fc, "No source specified");
818 file = filp_open(fc->source, O_RDONLY | O_LARGEFILE, 0);
819 if (IS_ERR(file))
820 return PTR_ERR(file);
821 sbi->dif0.file = file;
822
823 if (S_ISREG(file_inode(sbi->dif0.file)->i_mode) &&
824 sbi->dif0.file->f_mapping->a_ops->read_folio)
825 return get_tree_nodev(fc, erofs_fc_fill_super);
826 }
827 #endif
828 return ret;
829 }
830
erofs_fc_reconfigure(struct fs_context * fc)831 static int erofs_fc_reconfigure(struct fs_context *fc)
832 {
833 struct super_block *sb = fc->root->d_sb;
834 struct erofs_sb_info *sbi = EROFS_SB(sb);
835 struct erofs_sb_info *new_sbi = fc->s_fs_info;
836
837 DBG_BUGON(!sb_rdonly(sb));
838
839 if (new_sbi->fsid || new_sbi->domain_id)
840 erofs_info(sb, "ignoring reconfiguration for fsid|domain_id.");
841
842 if (test_opt(&new_sbi->opt, POSIX_ACL))
843 fc->sb_flags |= SB_POSIXACL;
844 else
845 fc->sb_flags &= ~SB_POSIXACL;
846
847 sbi->opt = new_sbi->opt;
848
849 fc->sb_flags |= SB_RDONLY;
850 return 0;
851 }
852
erofs_release_device_info(int id,void * ptr,void * data)853 static int erofs_release_device_info(int id, void *ptr, void *data)
854 {
855 struct erofs_device_info *dif = ptr;
856
857 fs_put_dax(dif->dax_dev, NULL);
858 if (dif->file)
859 fput(dif->file);
860 erofs_fscache_unregister_cookie(dif->fscache);
861 dif->fscache = NULL;
862 kfree(dif->path);
863 kfree(dif);
864 return 0;
865 }
866
erofs_free_dev_context(struct erofs_dev_context * devs)867 static void erofs_free_dev_context(struct erofs_dev_context *devs)
868 {
869 if (!devs)
870 return;
871 idr_for_each(&devs->tree, &erofs_release_device_info, NULL);
872 idr_destroy(&devs->tree);
873 kfree(devs);
874 }
875
erofs_sb_free(struct erofs_sb_info * sbi)876 static void erofs_sb_free(struct erofs_sb_info *sbi)
877 {
878 erofs_free_dev_context(sbi->devs);
879 kfree(sbi->fsid);
880 kfree_sensitive(sbi->domain_id);
881 if (sbi->dif0.file)
882 fput(sbi->dif0.file);
883 kfree(sbi->volume_name);
884 kfree(sbi);
885 }
886
erofs_fc_free(struct fs_context * fc)887 static void erofs_fc_free(struct fs_context *fc)
888 {
889 struct erofs_sb_info *sbi = fc->s_fs_info;
890
891 if (sbi) /* free here if an error occurs before transferring to sb */
892 erofs_sb_free(sbi);
893 }
894
895 static const struct fs_context_operations erofs_context_ops = {
896 .parse_param = erofs_fc_parse_param,
897 .get_tree = erofs_fc_get_tree,
898 .reconfigure = erofs_fc_reconfigure,
899 .free = erofs_fc_free,
900 };
901
erofs_init_fs_context(struct fs_context * fc)902 static int erofs_init_fs_context(struct fs_context *fc)
903 {
904 struct erofs_sb_info *sbi;
905
906 sbi = kzalloc_obj(*sbi);
907 if (!sbi)
908 return -ENOMEM;
909
910 sbi->devs = kzalloc_obj(struct erofs_dev_context);
911 if (!sbi->devs) {
912 kfree(sbi);
913 return -ENOMEM;
914 }
915 fc->s_fs_info = sbi;
916
917 idr_init(&sbi->devs->tree);
918 init_rwsem(&sbi->devs->rwsem);
919 erofs_default_options(sbi);
920 fc->ops = &erofs_context_ops;
921 return 0;
922 }
923
erofs_drop_internal_inodes(struct erofs_sb_info * sbi)924 static void erofs_drop_internal_inodes(struct erofs_sb_info *sbi)
925 {
926 iput(sbi->packed_inode);
927 sbi->packed_inode = NULL;
928 iput(sbi->metabox_inode);
929 sbi->metabox_inode = NULL;
930 #ifdef CONFIG_EROFS_FS_ZIP
931 iput(sbi->managed_cache);
932 sbi->managed_cache = NULL;
933 #endif
934 }
935
erofs_kill_sb(struct super_block * sb)936 static void erofs_kill_sb(struct super_block *sb)
937 {
938 struct erofs_sb_info *sbi = EROFS_SB(sb);
939
940 if ((IS_ENABLED(CONFIG_EROFS_FS_ONDEMAND) && sbi->fsid) ||
941 sbi->dif0.file)
942 kill_anon_super(sb);
943 else
944 kill_block_super(sb);
945 erofs_drop_internal_inodes(sbi);
946 fs_put_dax(sbi->dif0.dax_dev, NULL);
947 erofs_fscache_unregister_fs(sb);
948 erofs_sb_free(sbi);
949 sb->s_fs_info = NULL;
950 }
951
erofs_put_super(struct super_block * sb)952 static void erofs_put_super(struct super_block *sb)
953 {
954 struct erofs_sb_info *const sbi = EROFS_SB(sb);
955
956 erofs_unregister_sysfs(sb);
957 erofs_shrinker_unregister(sb);
958 erofs_xattr_prefixes_cleanup(sb);
959 erofs_drop_internal_inodes(sbi);
960 erofs_free_dev_context(sbi->devs);
961 sbi->devs = NULL;
962 erofs_fscache_unregister_fs(sb);
963 }
964
965 static struct file_system_type erofs_fs_type = {
966 .owner = THIS_MODULE,
967 .name = "erofs",
968 .init_fs_context = erofs_init_fs_context,
969 .kill_sb = erofs_kill_sb,
970 .fs_flags = FS_REQUIRES_DEV | FS_ALLOW_IDMAP,
971 };
972 MODULE_ALIAS_FS("erofs");
973
974 #if defined(CONFIG_EROFS_FS_ONDEMAND) || defined(CONFIG_EROFS_FS_PAGE_CACHE_SHARE)
erofs_free_anon_inode(struct inode * inode)975 static void erofs_free_anon_inode(struct inode *inode)
976 {
977 struct erofs_inode *vi = EROFS_I(inode);
978
979 #ifdef CONFIG_EROFS_FS_PAGE_CACHE_SHARE
980 kfree(vi->fingerprint.opaque);
981 #endif
982 kmem_cache_free(erofs_inode_cachep, vi);
983 }
984
985 static const struct super_operations erofs_anon_sops = {
986 .alloc_inode = erofs_alloc_inode,
987 .drop_inode = inode_just_drop,
988 .free_inode = erofs_free_anon_inode,
989 };
990
erofs_anon_init_fs_context(struct fs_context * fc)991 static int erofs_anon_init_fs_context(struct fs_context *fc)
992 {
993 struct pseudo_fs_context *ctx;
994
995 ctx = init_pseudo(fc, EROFS_SUPER_MAGIC);
996 if (!ctx)
997 return -ENOMEM;
998 ctx->ops = &erofs_anon_sops;
999 return 0;
1000 }
1001
1002 struct file_system_type erofs_anon_fs_type = {
1003 .name = "pseudo_erofs",
1004 .init_fs_context = erofs_anon_init_fs_context,
1005 .kill_sb = kill_anon_super,
1006 };
1007 #endif
1008
erofs_module_init(void)1009 static int __init erofs_module_init(void)
1010 {
1011 int err;
1012
1013 erofs_check_ondisk_layout_definitions();
1014
1015 erofs_inode_cachep = kmem_cache_create("erofs_inode",
1016 sizeof(struct erofs_inode), 0,
1017 SLAB_RECLAIM_ACCOUNT | SLAB_ACCOUNT,
1018 erofs_inode_init_once);
1019 if (!erofs_inode_cachep)
1020 return -ENOMEM;
1021
1022 err = erofs_init_shrinker();
1023 if (err)
1024 goto shrinker_err;
1025
1026 err = z_erofs_init_subsystem();
1027 if (err)
1028 goto zip_err;
1029
1030 err = erofs_init_sysfs();
1031 if (err)
1032 goto sysfs_err;
1033
1034 err = erofs_init_ishare();
1035 if (err)
1036 goto ishare_err;
1037
1038 err = register_filesystem(&erofs_fs_type);
1039 if (err)
1040 goto fs_err;
1041
1042 return 0;
1043
1044 fs_err:
1045 erofs_exit_ishare();
1046 ishare_err:
1047 erofs_exit_sysfs();
1048 sysfs_err:
1049 z_erofs_exit_subsystem();
1050 zip_err:
1051 erofs_exit_shrinker();
1052 shrinker_err:
1053 kmem_cache_destroy(erofs_inode_cachep);
1054 return err;
1055 }
1056
erofs_module_exit(void)1057 static void __exit erofs_module_exit(void)
1058 {
1059 unregister_filesystem(&erofs_fs_type);
1060
1061 /* Ensure all RCU free inodes / pclusters are safe to be destroyed. */
1062 rcu_barrier();
1063
1064 erofs_exit_ishare();
1065 erofs_exit_sysfs();
1066 z_erofs_exit_subsystem();
1067 erofs_exit_shrinker();
1068 kmem_cache_destroy(erofs_inode_cachep);
1069 }
1070
erofs_statfs(struct dentry * dentry,struct kstatfs * buf)1071 static int erofs_statfs(struct dentry *dentry, struct kstatfs *buf)
1072 {
1073 struct super_block *sb = dentry->d_sb;
1074 struct erofs_sb_info *sbi = EROFS_SB(sb);
1075
1076 buf->f_type = sb->s_magic;
1077 buf->f_bsize = sb->s_blocksize;
1078 buf->f_blocks = sbi->total_blocks;
1079 buf->f_bfree = buf->f_bavail = 0;
1080 buf->f_files = ULLONG_MAX;
1081 buf->f_ffree = ULLONG_MAX - sbi->inos;
1082 buf->f_namelen = EROFS_NAME_LEN;
1083
1084 if (uuid_is_null(&sb->s_uuid))
1085 buf->f_fsid = u64_to_fsid(!sb->s_bdev ? 0 :
1086 huge_encode_dev(sb->s_bdev->bd_dev));
1087 else
1088 buf->f_fsid = uuid_to_fsid(sb->s_uuid.b);
1089 return 0;
1090 }
1091
erofs_show_options(struct seq_file * seq,struct dentry * root)1092 static int erofs_show_options(struct seq_file *seq, struct dentry *root)
1093 {
1094 struct erofs_sb_info *sbi = EROFS_SB(root->d_sb);
1095 struct erofs_mount_opts *opt = &sbi->opt;
1096
1097 if (IS_ENABLED(CONFIG_EROFS_FS_XATTR))
1098 seq_puts(seq, test_opt(opt, XATTR_USER) ?
1099 ",user_xattr" : ",nouser_xattr");
1100 if (IS_ENABLED(CONFIG_EROFS_FS_POSIX_ACL))
1101 seq_puts(seq, test_opt(opt, POSIX_ACL) ? ",acl" : ",noacl");
1102 if (IS_ENABLED(CONFIG_EROFS_FS_ZIP))
1103 seq_printf(seq, ",cache_strategy=%s",
1104 erofs_param_cache_strategy[opt->cache_strategy].name);
1105 if (test_opt(opt, DAX_ALWAYS))
1106 seq_puts(seq, ",dax=always");
1107 if (test_opt(opt, DAX_NEVER))
1108 seq_puts(seq, ",dax=never");
1109 if (erofs_is_fileio_mode(sbi) && test_opt(opt, DIRECT_IO))
1110 seq_puts(seq, ",directio");
1111 #ifdef CONFIG_EROFS_FS_ONDEMAND
1112 if (sbi->fsid)
1113 seq_printf(seq, ",fsid=%s", sbi->fsid);
1114 if (sbi->domain_id)
1115 seq_printf(seq, ",domain_id=%s", sbi->domain_id);
1116 #endif
1117 if (sbi->dif0.fsoff)
1118 seq_printf(seq, ",fsoffset=%llu", sbi->dif0.fsoff);
1119 if (test_opt(opt, INODE_SHARE))
1120 seq_puts(seq, ",inode_share");
1121 return 0;
1122 }
1123
erofs_evict_inode(struct inode * inode)1124 static void erofs_evict_inode(struct inode *inode)
1125 {
1126 if (IS_DAX(inode))
1127 dax_break_layout_final(inode);
1128 erofs_ishare_free_inode(inode);
1129 truncate_inode_pages_final(&inode->i_data);
1130 clear_inode(inode);
1131 }
1132
1133 const struct super_operations erofs_sops = {
1134 .put_super = erofs_put_super,
1135 .alloc_inode = erofs_alloc_inode,
1136 .free_inode = erofs_free_inode,
1137 .evict_inode = erofs_evict_inode,
1138 .statfs = erofs_statfs,
1139 .show_options = erofs_show_options,
1140 };
1141
1142 module_init(erofs_module_init);
1143 module_exit(erofs_module_exit);
1144
1145 MODULE_DESCRIPTION("Enhanced ROM File System");
1146 MODULE_AUTHOR("Gao Xiang, Chao Yu, Miao Xie, CONSUMER BG, HUAWEI Inc.");
1147 MODULE_LICENSE("GPL");
1148