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 size_t len = 1 << EROFS_SB(sb)->blkszbits;
43 struct erofs_super_block *dsb;
44 u32 expected_crc, crc;
45
46 if (len > EROFS_SUPER_OFFSET)
47 len -= EROFS_SUPER_OFFSET;
48
49 dsb = kmemdup(sbdata + EROFS_SUPER_OFFSET, len, GFP_KERNEL);
50 if (!dsb)
51 return -ENOMEM;
52
53 expected_crc = le32_to_cpu(dsb->checksum);
54 dsb->checksum = 0;
55 /* to allow for x86 boot sectors and other oddities. */
56 crc = crc32c(~0, dsb, len);
57 kfree(dsb);
58
59 if (crc != expected_crc) {
60 erofs_err(sb, "invalid checksum 0x%08x, 0x%08x expected",
61 crc, expected_crc);
62 return -EBADMSG;
63 }
64 return 0;
65 }
66
erofs_inode_init_once(void * ptr)67 static void erofs_inode_init_once(void *ptr)
68 {
69 struct erofs_inode *vi = ptr;
70
71 inode_init_once(&vi->vfs_inode);
72 }
73
erofs_alloc_inode(struct super_block * sb)74 static struct inode *erofs_alloc_inode(struct super_block *sb)
75 {
76 struct erofs_inode *vi =
77 alloc_inode_sb(sb, erofs_inode_cachep, GFP_KERNEL);
78
79 if (!vi)
80 return NULL;
81
82 /* zero out everything except vfs_inode */
83 memset(vi, 0, offsetof(struct erofs_inode, vfs_inode));
84 return &vi->vfs_inode;
85 }
86
erofs_free_inode(struct inode * inode)87 static void erofs_free_inode(struct inode *inode)
88 {
89 struct erofs_inode *vi = EROFS_I(inode);
90
91 if (inode->i_op == &erofs_fast_symlink_iops)
92 kfree(inode->i_link);
93 kfree(vi->xattr_shared_xattrs);
94 kmem_cache_free(erofs_inode_cachep, vi);
95 }
96
97 /* 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)98 void *erofs_read_metadata(struct super_block *sb, struct erofs_buf *buf,
99 erofs_off_t *offset, int *lengthp)
100 {
101 u8 *buffer, *ptr;
102 int len, i, cnt;
103
104 *offset = round_up(*offset, 4);
105 ptr = erofs_bread(buf, *offset, EROFS_KMAP);
106 if (IS_ERR(ptr))
107 return ptr;
108
109 len = le16_to_cpu(*(__le16 *)ptr);
110 if (!len)
111 len = U16_MAX + 1;
112 buffer = kmalloc(len, GFP_KERNEL);
113 if (!buffer)
114 return ERR_PTR(-ENOMEM);
115 *offset += sizeof(__le16);
116 *lengthp = len;
117
118 for (i = 0; i < len; i += cnt) {
119 cnt = min_t(int, sb->s_blocksize - erofs_blkoff(sb, *offset),
120 len - i);
121 ptr = erofs_bread(buf, *offset, EROFS_KMAP);
122 if (IS_ERR(ptr)) {
123 kfree(buffer);
124 return ptr;
125 }
126 memcpy(buffer + i, ptr, cnt);
127 *offset += cnt;
128 }
129 return buffer;
130 }
131
132 #ifndef CONFIG_EROFS_FS_ZIP
z_erofs_parse_cfgs(struct super_block * sb,struct erofs_super_block * dsb)133 static int z_erofs_parse_cfgs(struct super_block *sb,
134 struct erofs_super_block *dsb)
135 {
136 if (!dsb->u1.available_compr_algs)
137 return 0;
138
139 erofs_err(sb, "compression disabled, unable to mount compressed EROFS");
140 return -EOPNOTSUPP;
141 }
142 #endif
143
erofs_init_device(struct erofs_buf * buf,struct super_block * sb,struct erofs_device_info * dif,erofs_off_t * pos)144 static int erofs_init_device(struct erofs_buf *buf, struct super_block *sb,
145 struct erofs_device_info *dif, erofs_off_t *pos)
146 {
147 struct erofs_sb_info *sbi = EROFS_SB(sb);
148 struct erofs_fscache *fscache;
149 struct erofs_deviceslot *dis;
150 struct file *file;
151
152 dis = erofs_read_metabuf(buf, sb, *pos, EROFS_KMAP);
153 if (IS_ERR(dis))
154 return PTR_ERR(dis);
155
156 if (!sbi->devs->flatdev && !dif->path) {
157 if (!dis->tag[0]) {
158 erofs_err(sb, "empty device tag @ pos %llu", *pos);
159 return -EINVAL;
160 }
161 dif->path = kmemdup_nul(dis->tag, sizeof(dis->tag), GFP_KERNEL);
162 if (!dif->path)
163 return -ENOMEM;
164 }
165
166 if (erofs_is_fscache_mode(sb)) {
167 fscache = erofs_fscache_register_cookie(sb, dif->path, 0);
168 if (IS_ERR(fscache))
169 return PTR_ERR(fscache);
170 dif->fscache = fscache;
171 } else if (!sbi->devs->flatdev) {
172 file = erofs_is_fileio_mode(sbi) ?
173 filp_open(dif->path, O_RDONLY | O_LARGEFILE, 0) :
174 bdev_file_open_by_path(dif->path,
175 BLK_OPEN_READ, sb->s_type, NULL);
176 if (IS_ERR(file))
177 return PTR_ERR(file);
178
179 if (!erofs_is_fileio_mode(sbi)) {
180 dif->dax_dev = fs_dax_get_by_bdev(file_bdev(file),
181 &dif->dax_part_off, NULL, NULL);
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);
190 dif->mapped_blkaddr = le32_to_cpu(dis->mapped_blkaddr);
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 return 0;
220
221 if (!sbi->devs->extra_devices && !erofs_is_fscache_mode(sb))
222 sbi->devs->flatdev = true;
223
224 sbi->device_id_mask = roundup_pow_of_two(ondisk_extradevs + 1) - 1;
225 pos = le16_to_cpu(dsb->devt_slotoff) * EROFS_DEVT_SLOT_SIZE;
226 down_read(&sbi->devs->rwsem);
227 if (sbi->devs->extra_devices) {
228 idr_for_each_entry(&sbi->devs->tree, dif, id) {
229 err = erofs_init_device(&buf, sb, dif, &pos);
230 if (err)
231 break;
232 }
233 } else {
234 for (id = 0; id < ondisk_extradevs; id++) {
235 dif = kzalloc(sizeof(*dif), GFP_KERNEL);
236 if (!dif) {
237 err = -ENOMEM;
238 break;
239 }
240
241 err = idr_alloc(&sbi->devs->tree, dif, 0, 0, GFP_KERNEL);
242 if (err < 0) {
243 kfree(dif);
244 break;
245 }
246 ++sbi->devs->extra_devices;
247
248 err = erofs_init_device(&buf, sb, dif, &pos);
249 if (err)
250 break;
251 }
252 }
253 up_read(&sbi->devs->rwsem);
254 erofs_put_metabuf(&buf);
255 return err;
256 }
257
erofs_read_superblock(struct super_block * sb)258 static int erofs_read_superblock(struct super_block *sb)
259 {
260 struct erofs_sb_info *sbi = EROFS_SB(sb);
261 struct erofs_buf buf = __EROFS_BUF_INITIALIZER;
262 struct erofs_super_block *dsb;
263 void *data;
264 int ret;
265
266 data = erofs_read_metabuf(&buf, sb, 0, EROFS_KMAP);
267 if (IS_ERR(data)) {
268 erofs_err(sb, "cannot read erofs superblock");
269 return PTR_ERR(data);
270 }
271
272 dsb = (struct erofs_super_block *)(data + EROFS_SUPER_OFFSET);
273 ret = -EINVAL;
274 if (le32_to_cpu(dsb->magic) != EROFS_SUPER_MAGIC_V1) {
275 erofs_err(sb, "cannot find valid erofs superblock");
276 goto out;
277 }
278
279 sbi->blkszbits = dsb->blkszbits;
280 if (sbi->blkszbits < 9 || sbi->blkszbits > PAGE_SHIFT) {
281 erofs_err(sb, "blkszbits %u isn't supported", sbi->blkszbits);
282 goto out;
283 }
284 if (dsb->dirblkbits) {
285 erofs_err(sb, "dirblkbits %u isn't supported", dsb->dirblkbits);
286 goto out;
287 }
288
289 sbi->feature_compat = le32_to_cpu(dsb->feature_compat);
290 if (erofs_sb_has_sb_chksum(sbi)) {
291 ret = erofs_superblock_csum_verify(sb, data);
292 if (ret)
293 goto out;
294 }
295
296 ret = -EINVAL;
297 sbi->feature_incompat = le32_to_cpu(dsb->feature_incompat);
298 if (sbi->feature_incompat & ~EROFS_ALL_FEATURE_INCOMPAT) {
299 erofs_err(sb, "unidentified incompatible feature %x, please upgrade kernel",
300 sbi->feature_incompat & ~EROFS_ALL_FEATURE_INCOMPAT);
301 goto out;
302 }
303
304 sbi->sb_size = 128 + dsb->sb_extslots * EROFS_SB_EXTSLOT_SIZE;
305 if (sbi->sb_size > PAGE_SIZE - EROFS_SUPER_OFFSET) {
306 erofs_err(sb, "invalid sb_extslots %u (more than a fs block)",
307 sbi->sb_size);
308 goto out;
309 }
310 sbi->dif0.blocks = le32_to_cpu(dsb->blocks);
311 sbi->meta_blkaddr = le32_to_cpu(dsb->meta_blkaddr);
312 #ifdef CONFIG_EROFS_FS_XATTR
313 sbi->xattr_blkaddr = le32_to_cpu(dsb->xattr_blkaddr);
314 sbi->xattr_prefix_start = le32_to_cpu(dsb->xattr_prefix_start);
315 sbi->xattr_prefix_count = dsb->xattr_prefix_count;
316 sbi->xattr_filter_reserved = dsb->xattr_filter_reserved;
317 #endif
318 sbi->islotbits = ilog2(sizeof(struct erofs_inode_compact));
319 sbi->root_nid = le16_to_cpu(dsb->root_nid);
320 sbi->packed_nid = le64_to_cpu(dsb->packed_nid);
321 sbi->inos = le64_to_cpu(dsb->inos);
322
323 sbi->build_time = le64_to_cpu(dsb->build_time);
324 sbi->build_time_nsec = le32_to_cpu(dsb->build_time_nsec);
325
326 super_set_uuid(sb, (void *)dsb->uuid, sizeof(dsb->uuid));
327
328 ret = strscpy(sbi->volume_name, dsb->volume_name,
329 sizeof(dsb->volume_name));
330 if (ret < 0) { /* -E2BIG */
331 erofs_err(sb, "bad volume name without NIL terminator");
332 ret = -EFSCORRUPTED;
333 goto out;
334 }
335
336 /* parse on-disk compression configurations */
337 ret = z_erofs_parse_cfgs(sb, dsb);
338 if (ret < 0)
339 goto out;
340
341 /* handle multiple devices */
342 ret = erofs_scan_devices(sb, dsb);
343
344 if (erofs_is_fscache_mode(sb))
345 erofs_info(sb, "[deprecated] fscache-based on-demand read feature in use. Use at your own risk!");
346 out:
347 erofs_put_metabuf(&buf);
348 return ret;
349 }
350
erofs_default_options(struct erofs_sb_info * sbi)351 static void erofs_default_options(struct erofs_sb_info *sbi)
352 {
353 #ifdef CONFIG_EROFS_FS_ZIP
354 sbi->opt.cache_strategy = EROFS_ZIP_CACHE_READAROUND;
355 sbi->opt.max_sync_decompress_pages = 3;
356 sbi->opt.sync_decompress = EROFS_SYNC_DECOMPRESS_AUTO;
357 #endif
358 #ifdef CONFIG_EROFS_FS_XATTR
359 set_opt(&sbi->opt, XATTR_USER);
360 #endif
361 #ifdef CONFIG_EROFS_FS_POSIX_ACL
362 set_opt(&sbi->opt, POSIX_ACL);
363 #endif
364 }
365
366 enum {
367 Opt_user_xattr, Opt_acl, Opt_cache_strategy, Opt_dax, Opt_dax_enum,
368 Opt_device, Opt_fsid, Opt_domain_id, Opt_directio,
369 Opt_err
370 };
371
372 static const struct constant_table erofs_param_cache_strategy[] = {
373 {"disabled", EROFS_ZIP_CACHE_DISABLED},
374 {"readahead", EROFS_ZIP_CACHE_READAHEAD},
375 {"readaround", EROFS_ZIP_CACHE_READAROUND},
376 {}
377 };
378
379 static const struct constant_table erofs_dax_param_enums[] = {
380 {"always", EROFS_MOUNT_DAX_ALWAYS},
381 {"never", EROFS_MOUNT_DAX_NEVER},
382 {}
383 };
384
385 static const struct fs_parameter_spec erofs_fs_parameters[] = {
386 fsparam_flag_no("user_xattr", Opt_user_xattr),
387 fsparam_flag_no("acl", Opt_acl),
388 fsparam_enum("cache_strategy", Opt_cache_strategy,
389 erofs_param_cache_strategy),
390 fsparam_flag("dax", Opt_dax),
391 fsparam_enum("dax", Opt_dax_enum, erofs_dax_param_enums),
392 fsparam_string("device", Opt_device),
393 fsparam_string("fsid", Opt_fsid),
394 fsparam_string("domain_id", Opt_domain_id),
395 fsparam_flag_no("directio", Opt_directio),
396 {}
397 };
398
erofs_fc_set_dax_mode(struct fs_context * fc,unsigned int mode)399 static bool erofs_fc_set_dax_mode(struct fs_context *fc, unsigned int mode)
400 {
401 #ifdef CONFIG_FS_DAX
402 struct erofs_sb_info *sbi = fc->s_fs_info;
403
404 switch (mode) {
405 case EROFS_MOUNT_DAX_ALWAYS:
406 set_opt(&sbi->opt, DAX_ALWAYS);
407 clear_opt(&sbi->opt, DAX_NEVER);
408 return true;
409 case EROFS_MOUNT_DAX_NEVER:
410 set_opt(&sbi->opt, DAX_NEVER);
411 clear_opt(&sbi->opt, DAX_ALWAYS);
412 return true;
413 default:
414 DBG_BUGON(1);
415 return false;
416 }
417 #else
418 errorfc(fc, "dax options not supported");
419 return false;
420 #endif
421 }
422
erofs_fc_parse_param(struct fs_context * fc,struct fs_parameter * param)423 static int erofs_fc_parse_param(struct fs_context *fc,
424 struct fs_parameter *param)
425 {
426 struct erofs_sb_info *sbi = fc->s_fs_info;
427 struct fs_parse_result result;
428 struct erofs_device_info *dif;
429 int opt, ret;
430
431 opt = fs_parse(fc, erofs_fs_parameters, param, &result);
432 if (opt < 0)
433 return opt;
434
435 switch (opt) {
436 case Opt_user_xattr:
437 #ifdef CONFIG_EROFS_FS_XATTR
438 if (result.boolean)
439 set_opt(&sbi->opt, XATTR_USER);
440 else
441 clear_opt(&sbi->opt, XATTR_USER);
442 #else
443 errorfc(fc, "{,no}user_xattr options not supported");
444 #endif
445 break;
446 case Opt_acl:
447 #ifdef CONFIG_EROFS_FS_POSIX_ACL
448 if (result.boolean)
449 set_opt(&sbi->opt, POSIX_ACL);
450 else
451 clear_opt(&sbi->opt, POSIX_ACL);
452 #else
453 errorfc(fc, "{,no}acl options not supported");
454 #endif
455 break;
456 case Opt_cache_strategy:
457 #ifdef CONFIG_EROFS_FS_ZIP
458 sbi->opt.cache_strategy = result.uint_32;
459 #else
460 errorfc(fc, "compression not supported, cache_strategy ignored");
461 #endif
462 break;
463 case Opt_dax:
464 if (!erofs_fc_set_dax_mode(fc, EROFS_MOUNT_DAX_ALWAYS))
465 return -EINVAL;
466 break;
467 case Opt_dax_enum:
468 if (!erofs_fc_set_dax_mode(fc, result.uint_32))
469 return -EINVAL;
470 break;
471 case Opt_device:
472 dif = kzalloc(sizeof(*dif), GFP_KERNEL);
473 if (!dif)
474 return -ENOMEM;
475 dif->path = kstrdup(param->string, GFP_KERNEL);
476 if (!dif->path) {
477 kfree(dif);
478 return -ENOMEM;
479 }
480 down_write(&sbi->devs->rwsem);
481 ret = idr_alloc(&sbi->devs->tree, dif, 0, 0, GFP_KERNEL);
482 up_write(&sbi->devs->rwsem);
483 if (ret < 0) {
484 kfree(dif->path);
485 kfree(dif);
486 return ret;
487 }
488 ++sbi->devs->extra_devices;
489 break;
490 #ifdef CONFIG_EROFS_FS_ONDEMAND
491 case Opt_fsid:
492 kfree(sbi->fsid);
493 sbi->fsid = kstrdup(param->string, GFP_KERNEL);
494 if (!sbi->fsid)
495 return -ENOMEM;
496 break;
497 case Opt_domain_id:
498 kfree(sbi->domain_id);
499 sbi->domain_id = kstrdup(param->string, GFP_KERNEL);
500 if (!sbi->domain_id)
501 return -ENOMEM;
502 break;
503 #else
504 case Opt_fsid:
505 case Opt_domain_id:
506 errorfc(fc, "%s option not supported", erofs_fs_parameters[opt].name);
507 break;
508 #endif
509 case Opt_directio:
510 #ifdef CONFIG_EROFS_FS_BACKED_BY_FILE
511 if (result.boolean)
512 set_opt(&sbi->opt, DIRECT_IO);
513 else
514 clear_opt(&sbi->opt, DIRECT_IO);
515 #else
516 errorfc(fc, "%s option not supported", erofs_fs_parameters[opt].name);
517 #endif
518 break;
519 default:
520 return -ENOPARAM;
521 }
522 return 0;
523 }
524
erofs_nfs_get_inode(struct super_block * sb,u64 ino,u32 generation)525 static struct inode *erofs_nfs_get_inode(struct super_block *sb,
526 u64 ino, u32 generation)
527 {
528 return erofs_iget(sb, ino);
529 }
530
erofs_fh_to_dentry(struct super_block * sb,struct fid * fid,int fh_len,int fh_type)531 static struct dentry *erofs_fh_to_dentry(struct super_block *sb,
532 struct fid *fid, int fh_len, int fh_type)
533 {
534 return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
535 erofs_nfs_get_inode);
536 }
537
erofs_fh_to_parent(struct super_block * sb,struct fid * fid,int fh_len,int fh_type)538 static struct dentry *erofs_fh_to_parent(struct super_block *sb,
539 struct fid *fid, int fh_len, int fh_type)
540 {
541 return generic_fh_to_parent(sb, fid, fh_len, fh_type,
542 erofs_nfs_get_inode);
543 }
544
erofs_get_parent(struct dentry * child)545 static struct dentry *erofs_get_parent(struct dentry *child)
546 {
547 erofs_nid_t nid;
548 unsigned int d_type;
549 int err;
550
551 err = erofs_namei(d_inode(child), &dotdot_name, &nid, &d_type);
552 if (err)
553 return ERR_PTR(err);
554 return d_obtain_alias(erofs_iget(child->d_sb, nid));
555 }
556
557 static const struct export_operations erofs_export_ops = {
558 .encode_fh = generic_encode_ino32_fh,
559 .fh_to_dentry = erofs_fh_to_dentry,
560 .fh_to_parent = erofs_fh_to_parent,
561 .get_parent = erofs_get_parent,
562 };
563
erofs_set_sysfs_name(struct super_block * sb)564 static void erofs_set_sysfs_name(struct super_block *sb)
565 {
566 struct erofs_sb_info *sbi = EROFS_SB(sb);
567
568 if (sbi->domain_id)
569 super_set_sysfs_name_generic(sb, "%s,%s", sbi->domain_id,
570 sbi->fsid);
571 else if (sbi->fsid)
572 super_set_sysfs_name_generic(sb, "%s", sbi->fsid);
573 else if (erofs_is_fileio_mode(sbi))
574 super_set_sysfs_name_generic(sb, "%s",
575 bdi_dev_name(sb->s_bdi));
576 else
577 super_set_sysfs_name_id(sb);
578 }
579
erofs_fc_fill_super(struct super_block * sb,struct fs_context * fc)580 static int erofs_fc_fill_super(struct super_block *sb, struct fs_context *fc)
581 {
582 struct inode *inode;
583 struct erofs_sb_info *sbi = EROFS_SB(sb);
584 int err;
585
586 sb->s_magic = EROFS_SUPER_MAGIC;
587 sb->s_flags |= SB_RDONLY | SB_NOATIME;
588 sb->s_maxbytes = MAX_LFS_FILESIZE;
589 sb->s_op = &erofs_sops;
590
591 sbi->blkszbits = PAGE_SHIFT;
592 if (!sb->s_bdev) {
593 sb->s_blocksize = PAGE_SIZE;
594 sb->s_blocksize_bits = PAGE_SHIFT;
595
596 if (erofs_is_fscache_mode(sb)) {
597 err = erofs_fscache_register_fs(sb);
598 if (err)
599 return err;
600 }
601 err = super_setup_bdi(sb);
602 if (err)
603 return err;
604 } else {
605 if (!sb_set_blocksize(sb, PAGE_SIZE)) {
606 errorfc(fc, "failed to set initial blksize");
607 return -EINVAL;
608 }
609
610 sbi->dif0.dax_dev = fs_dax_get_by_bdev(sb->s_bdev,
611 &sbi->dif0.dax_part_off, NULL, NULL);
612 }
613
614 err = erofs_read_superblock(sb);
615 if (err)
616 return err;
617
618 if (sb->s_blocksize_bits != sbi->blkszbits) {
619 if (erofs_is_fscache_mode(sb)) {
620 errorfc(fc, "unsupported blksize for fscache mode");
621 return -EINVAL;
622 }
623
624 if (erofs_is_fileio_mode(sbi)) {
625 sb->s_blocksize = 1 << sbi->blkszbits;
626 sb->s_blocksize_bits = sbi->blkszbits;
627 } else if (!sb_set_blocksize(sb, 1 << sbi->blkszbits)) {
628 errorfc(fc, "failed to set erofs blksize");
629 return -EINVAL;
630 }
631 }
632
633 if (test_opt(&sbi->opt, DAX_ALWAYS)) {
634 if (!sbi->dif0.dax_dev) {
635 errorfc(fc, "DAX unsupported by block device. Turning off DAX.");
636 clear_opt(&sbi->opt, DAX_ALWAYS);
637 } else if (sbi->blkszbits != PAGE_SHIFT) {
638 errorfc(fc, "unsupported blocksize for DAX");
639 clear_opt(&sbi->opt, DAX_ALWAYS);
640 }
641 }
642
643 sb->s_time_gran = 1;
644 sb->s_xattr = erofs_xattr_handlers;
645 sb->s_export_op = &erofs_export_ops;
646
647 if (test_opt(&sbi->opt, POSIX_ACL))
648 sb->s_flags |= SB_POSIXACL;
649 else
650 sb->s_flags &= ~SB_POSIXACL;
651
652 #ifdef CONFIG_EROFS_FS_ZIP
653 xa_init(&sbi->managed_pslots);
654 #endif
655
656 inode = erofs_iget(sb, sbi->root_nid);
657 if (IS_ERR(inode))
658 return PTR_ERR(inode);
659
660 if (!S_ISDIR(inode->i_mode)) {
661 erofs_err(sb, "rootino(nid %llu) is not a directory(i_mode %o)",
662 sbi->root_nid, inode->i_mode);
663 iput(inode);
664 return -EINVAL;
665 }
666
667 sb->s_root = d_make_root(inode);
668 if (!sb->s_root)
669 return -ENOMEM;
670
671 erofs_shrinker_register(sb);
672 if (erofs_sb_has_fragments(sbi) && sbi->packed_nid) {
673 sbi->packed_inode = erofs_iget(sb, sbi->packed_nid);
674 if (IS_ERR(sbi->packed_inode)) {
675 err = PTR_ERR(sbi->packed_inode);
676 sbi->packed_inode = NULL;
677 return err;
678 }
679 }
680 err = erofs_init_managed_cache(sb);
681 if (err)
682 return err;
683
684 err = erofs_xattr_prefixes_init(sb);
685 if (err)
686 return err;
687
688 erofs_set_sysfs_name(sb);
689 err = erofs_register_sysfs(sb);
690 if (err)
691 return err;
692
693 erofs_info(sb, "mounted with root inode @ nid %llu.", sbi->root_nid);
694 return 0;
695 }
696
erofs_fc_get_tree(struct fs_context * fc)697 static int erofs_fc_get_tree(struct fs_context *fc)
698 {
699 struct erofs_sb_info *sbi = fc->s_fs_info;
700 int ret;
701
702 if (IS_ENABLED(CONFIG_EROFS_FS_ONDEMAND) && sbi->fsid)
703 return get_tree_nodev(fc, erofs_fc_fill_super);
704
705 ret = get_tree_bdev_flags(fc, erofs_fc_fill_super,
706 IS_ENABLED(CONFIG_EROFS_FS_BACKED_BY_FILE) ?
707 GET_TREE_BDEV_QUIET_LOOKUP : 0);
708 #ifdef CONFIG_EROFS_FS_BACKED_BY_FILE
709 if (ret == -ENOTBLK) {
710 struct file *file;
711
712 if (!fc->source)
713 return invalf(fc, "No source specified");
714 file = filp_open(fc->source, O_RDONLY | O_LARGEFILE, 0);
715 if (IS_ERR(file))
716 return PTR_ERR(file);
717 sbi->dif0.file = file;
718
719 if (S_ISREG(file_inode(sbi->dif0.file)->i_mode) &&
720 sbi->dif0.file->f_mapping->a_ops->read_folio)
721 return get_tree_nodev(fc, erofs_fc_fill_super);
722 }
723 #endif
724 return ret;
725 }
726
erofs_fc_reconfigure(struct fs_context * fc)727 static int erofs_fc_reconfigure(struct fs_context *fc)
728 {
729 struct super_block *sb = fc->root->d_sb;
730 struct erofs_sb_info *sbi = EROFS_SB(sb);
731 struct erofs_sb_info *new_sbi = fc->s_fs_info;
732
733 DBG_BUGON(!sb_rdonly(sb));
734
735 if (new_sbi->fsid || new_sbi->domain_id)
736 erofs_info(sb, "ignoring reconfiguration for fsid|domain_id.");
737
738 if (test_opt(&new_sbi->opt, POSIX_ACL))
739 fc->sb_flags |= SB_POSIXACL;
740 else
741 fc->sb_flags &= ~SB_POSIXACL;
742
743 sbi->opt = new_sbi->opt;
744
745 fc->sb_flags |= SB_RDONLY;
746 return 0;
747 }
748
erofs_release_device_info(int id,void * ptr,void * data)749 static int erofs_release_device_info(int id, void *ptr, void *data)
750 {
751 struct erofs_device_info *dif = ptr;
752
753 fs_put_dax(dif->dax_dev, NULL);
754 if (dif->file)
755 fput(dif->file);
756 erofs_fscache_unregister_cookie(dif->fscache);
757 dif->fscache = NULL;
758 kfree(dif->path);
759 kfree(dif);
760 return 0;
761 }
762
erofs_free_dev_context(struct erofs_dev_context * devs)763 static void erofs_free_dev_context(struct erofs_dev_context *devs)
764 {
765 if (!devs)
766 return;
767 idr_for_each(&devs->tree, &erofs_release_device_info, NULL);
768 idr_destroy(&devs->tree);
769 kfree(devs);
770 }
771
erofs_sb_free(struct erofs_sb_info * sbi)772 static void erofs_sb_free(struct erofs_sb_info *sbi)
773 {
774 erofs_free_dev_context(sbi->devs);
775 kfree(sbi->fsid);
776 kfree(sbi->domain_id);
777 if (sbi->dif0.file)
778 fput(sbi->dif0.file);
779 kfree(sbi);
780 }
781
erofs_fc_free(struct fs_context * fc)782 static void erofs_fc_free(struct fs_context *fc)
783 {
784 struct erofs_sb_info *sbi = fc->s_fs_info;
785
786 if (sbi) /* free here if an error occurs before transferring to sb */
787 erofs_sb_free(sbi);
788 }
789
790 static const struct fs_context_operations erofs_context_ops = {
791 .parse_param = erofs_fc_parse_param,
792 .get_tree = erofs_fc_get_tree,
793 .reconfigure = erofs_fc_reconfigure,
794 .free = erofs_fc_free,
795 };
796
erofs_init_fs_context(struct fs_context * fc)797 static int erofs_init_fs_context(struct fs_context *fc)
798 {
799 struct erofs_sb_info *sbi;
800
801 sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
802 if (!sbi)
803 return -ENOMEM;
804
805 sbi->devs = kzalloc(sizeof(struct erofs_dev_context), GFP_KERNEL);
806 if (!sbi->devs) {
807 kfree(sbi);
808 return -ENOMEM;
809 }
810 fc->s_fs_info = sbi;
811
812 idr_init(&sbi->devs->tree);
813 init_rwsem(&sbi->devs->rwsem);
814 erofs_default_options(sbi);
815 fc->ops = &erofs_context_ops;
816 return 0;
817 }
818
erofs_kill_sb(struct super_block * sb)819 static void erofs_kill_sb(struct super_block *sb)
820 {
821 struct erofs_sb_info *sbi = EROFS_SB(sb);
822
823 if ((IS_ENABLED(CONFIG_EROFS_FS_ONDEMAND) && sbi->fsid) ||
824 sbi->dif0.file)
825 kill_anon_super(sb);
826 else
827 kill_block_super(sb);
828 fs_put_dax(sbi->dif0.dax_dev, NULL);
829 erofs_fscache_unregister_fs(sb);
830 erofs_sb_free(sbi);
831 sb->s_fs_info = NULL;
832 }
833
erofs_put_super(struct super_block * sb)834 static void erofs_put_super(struct super_block *sb)
835 {
836 struct erofs_sb_info *const sbi = EROFS_SB(sb);
837
838 DBG_BUGON(!sbi);
839
840 erofs_unregister_sysfs(sb);
841 erofs_shrinker_unregister(sb);
842 erofs_xattr_prefixes_cleanup(sb);
843 #ifdef CONFIG_EROFS_FS_ZIP
844 iput(sbi->managed_cache);
845 sbi->managed_cache = NULL;
846 #endif
847 iput(sbi->packed_inode);
848 sbi->packed_inode = NULL;
849 erofs_free_dev_context(sbi->devs);
850 sbi->devs = NULL;
851 erofs_fscache_unregister_fs(sb);
852 }
853
854 static struct file_system_type erofs_fs_type = {
855 .owner = THIS_MODULE,
856 .name = "erofs",
857 .init_fs_context = erofs_init_fs_context,
858 .kill_sb = erofs_kill_sb,
859 .fs_flags = FS_REQUIRES_DEV | FS_ALLOW_IDMAP,
860 };
861 MODULE_ALIAS_FS("erofs");
862
erofs_module_init(void)863 static int __init erofs_module_init(void)
864 {
865 int err;
866
867 erofs_check_ondisk_layout_definitions();
868
869 erofs_inode_cachep = kmem_cache_create("erofs_inode",
870 sizeof(struct erofs_inode), 0,
871 SLAB_RECLAIM_ACCOUNT | SLAB_ACCOUNT,
872 erofs_inode_init_once);
873 if (!erofs_inode_cachep)
874 return -ENOMEM;
875
876 err = erofs_init_shrinker();
877 if (err)
878 goto shrinker_err;
879
880 err = z_erofs_init_subsystem();
881 if (err)
882 goto zip_err;
883
884 err = erofs_init_sysfs();
885 if (err)
886 goto sysfs_err;
887
888 err = register_filesystem(&erofs_fs_type);
889 if (err)
890 goto fs_err;
891
892 return 0;
893
894 fs_err:
895 erofs_exit_sysfs();
896 sysfs_err:
897 z_erofs_exit_subsystem();
898 zip_err:
899 erofs_exit_shrinker();
900 shrinker_err:
901 kmem_cache_destroy(erofs_inode_cachep);
902 return err;
903 }
904
erofs_module_exit(void)905 static void __exit erofs_module_exit(void)
906 {
907 unregister_filesystem(&erofs_fs_type);
908
909 /* Ensure all RCU free inodes / pclusters are safe to be destroyed. */
910 rcu_barrier();
911
912 erofs_exit_sysfs();
913 z_erofs_exit_subsystem();
914 erofs_exit_shrinker();
915 kmem_cache_destroy(erofs_inode_cachep);
916 }
917
erofs_statfs(struct dentry * dentry,struct kstatfs * buf)918 static int erofs_statfs(struct dentry *dentry, struct kstatfs *buf)
919 {
920 struct super_block *sb = dentry->d_sb;
921 struct erofs_sb_info *sbi = EROFS_SB(sb);
922
923 buf->f_type = sb->s_magic;
924 buf->f_bsize = sb->s_blocksize;
925 buf->f_blocks = sbi->total_blocks;
926 buf->f_bfree = buf->f_bavail = 0;
927 buf->f_files = ULLONG_MAX;
928 buf->f_ffree = ULLONG_MAX - sbi->inos;
929 buf->f_namelen = EROFS_NAME_LEN;
930
931 if (uuid_is_null(&sb->s_uuid))
932 buf->f_fsid = u64_to_fsid(!sb->s_bdev ? 0 :
933 huge_encode_dev(sb->s_bdev->bd_dev));
934 else
935 buf->f_fsid = uuid_to_fsid(sb->s_uuid.b);
936 return 0;
937 }
938
erofs_show_options(struct seq_file * seq,struct dentry * root)939 static int erofs_show_options(struct seq_file *seq, struct dentry *root)
940 {
941 struct erofs_sb_info *sbi = EROFS_SB(root->d_sb);
942 struct erofs_mount_opts *opt = &sbi->opt;
943
944 if (IS_ENABLED(CONFIG_EROFS_FS_XATTR))
945 seq_puts(seq, test_opt(opt, XATTR_USER) ?
946 ",user_xattr" : ",nouser_xattr");
947 if (IS_ENABLED(CONFIG_EROFS_FS_POSIX_ACL))
948 seq_puts(seq, test_opt(opt, POSIX_ACL) ? ",acl" : ",noacl");
949 if (IS_ENABLED(CONFIG_EROFS_FS_ZIP))
950 seq_printf(seq, ",cache_strategy=%s",
951 erofs_param_cache_strategy[opt->cache_strategy].name);
952 if (test_opt(opt, DAX_ALWAYS))
953 seq_puts(seq, ",dax=always");
954 if (test_opt(opt, DAX_NEVER))
955 seq_puts(seq, ",dax=never");
956 if (erofs_is_fileio_mode(sbi) && test_opt(opt, DIRECT_IO))
957 seq_puts(seq, ",directio");
958 #ifdef CONFIG_EROFS_FS_ONDEMAND
959 if (sbi->fsid)
960 seq_printf(seq, ",fsid=%s", sbi->fsid);
961 if (sbi->domain_id)
962 seq_printf(seq, ",domain_id=%s", sbi->domain_id);
963 #endif
964 return 0;
965 }
966
967 const struct super_operations erofs_sops = {
968 .put_super = erofs_put_super,
969 .alloc_inode = erofs_alloc_inode,
970 .free_inode = erofs_free_inode,
971 .statfs = erofs_statfs,
972 .show_options = erofs_show_options,
973 };
974
975 module_init(erofs_module_init);
976 module_exit(erofs_module_exit);
977
978 MODULE_DESCRIPTION("Enhanced ROM File System");
979 MODULE_AUTHOR("Gao Xiang, Chao Yu, Miao Xie, CONSUMER BG, HUAWEI Inc.");
980 MODULE_LICENSE("GPL");
981