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