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 "xattr.h"
14
15#define CREATE_TRACE_POINTS
16#include <trace/events/erofs.h>
17
18static struct kmem_cache *erofs_inode_cachep __read_mostly;
19
20void _erofs_err(struct super_block *sb, const char *func, const char *fmt, ...)
21{
22 struct va_format vaf;
23 va_list args;
24
25 va_start(args, fmt);
26
27 vaf.fmt = fmt;
28 vaf.va = &args;
29
30 if (sb)
31 pr_err("(device %s): %s: %pV", sb->s_id, func, &vaf);
32 else
33 pr_err("%s: %pV", func, &vaf);
34 va_end(args);
35}
36
37void _erofs_info(struct super_block *sb, const char *func, const char *fmt, ...)
38{
39 struct va_format vaf;
40 va_list args;
41
42 va_start(args, fmt);
43
44 vaf.fmt = fmt;
45 vaf.va = &args;
46
47 if (sb)
48 pr_info("(device %s): %pV", sb->s_id, &vaf);
49 else
50 pr_info("%pV", &vaf);
51 va_end(args);
52}
53
54static int erofs_superblock_csum_verify(struct super_block *sb, void *sbdata)
55{
56 size_t len = 1 << EROFS_SB(sb)->blkszbits;
57 struct erofs_super_block *dsb;
58 u32 expected_crc, crc;
59
60 if (len > EROFS_SUPER_OFFSET)
61 len -= EROFS_SUPER_OFFSET;
62
63 dsb = kmemdup(p: sbdata + EROFS_SUPER_OFFSET, size: len, GFP_KERNEL);
64 if (!dsb)
65 return -ENOMEM;
66
67 expected_crc = le32_to_cpu(dsb->checksum);
68 dsb->checksum = 0;
69 /* to allow for x86 boot sectors and other oddities. */
70 crc = crc32c(crc: ~0, address: dsb, length: len);
71 kfree(objp: dsb);
72
73 if (crc != expected_crc) {
74 erofs_err(sb, "invalid checksum 0x%08x, 0x%08x expected",
75 crc, expected_crc);
76 return -EBADMSG;
77 }
78 return 0;
79}
80
81static void erofs_inode_init_once(void *ptr)
82{
83 struct erofs_inode *vi = ptr;
84
85 inode_init_once(&vi->vfs_inode);
86}
87
88static struct inode *erofs_alloc_inode(struct super_block *sb)
89{
90 struct erofs_inode *vi =
91 alloc_inode_sb(sb, cache: erofs_inode_cachep, GFP_KERNEL);
92
93 if (!vi)
94 return NULL;
95
96 /* zero out everything except vfs_inode */
97 memset(vi, 0, offsetof(struct erofs_inode, vfs_inode));
98 return &vi->vfs_inode;
99}
100
101static void erofs_free_inode(struct inode *inode)
102{
103 struct erofs_inode *vi = EROFS_I(inode);
104
105 if (inode->i_op == &erofs_fast_symlink_iops)
106 kfree(objp: inode->i_link);
107 kfree(objp: vi->xattr_shared_xattrs);
108 kmem_cache_free(s: erofs_inode_cachep, objp: vi);
109}
110
111static bool check_layout_compatibility(struct super_block *sb,
112 struct erofs_super_block *dsb)
113{
114 const unsigned int feature = le32_to_cpu(dsb->feature_incompat);
115
116 EROFS_SB(sb)->feature_incompat = feature;
117
118 /* check if current kernel meets all mandatory requirements */
119 if (feature & (~EROFS_ALL_FEATURE_INCOMPAT)) {
120 erofs_err(sb, "unidentified incompatible feature %x, please upgrade kernel",
121 feature & ~EROFS_ALL_FEATURE_INCOMPAT);
122 return false;
123 }
124 return true;
125}
126
127/* read variable-sized metadata, offset will be aligned by 4-byte */
128void *erofs_read_metadata(struct super_block *sb, struct erofs_buf *buf,
129 erofs_off_t *offset, int *lengthp)
130{
131 u8 *buffer, *ptr;
132 int len, i, cnt;
133
134 *offset = round_up(*offset, 4);
135 ptr = erofs_bread(buf, erofs_blknr(sb, *offset), type: EROFS_KMAP);
136 if (IS_ERR(ptr))
137 return ptr;
138
139 len = le16_to_cpu(*(__le16 *)&ptr[erofs_blkoff(sb, *offset)]);
140 if (!len)
141 len = U16_MAX + 1;
142 buffer = kmalloc(size: len, GFP_KERNEL);
143 if (!buffer)
144 return ERR_PTR(error: -ENOMEM);
145 *offset += sizeof(__le16);
146 *lengthp = len;
147
148 for (i = 0; i < len; i += cnt) {
149 cnt = min_t(int, sb->s_blocksize - erofs_blkoff(sb, *offset),
150 len - i);
151 ptr = erofs_bread(buf, erofs_blknr(sb, *offset), type: EROFS_KMAP);
152 if (IS_ERR(ptr)) {
153 kfree(objp: buffer);
154 return ptr;
155 }
156 memcpy(buffer + i, ptr + erofs_blkoff(sb, *offset), cnt);
157 *offset += cnt;
158 }
159 return buffer;
160}
161
162#ifndef CONFIG_EROFS_FS_ZIP
163static int z_erofs_parse_cfgs(struct super_block *sb,
164 struct erofs_super_block *dsb)
165{
166 if (!dsb->u1.available_compr_algs)
167 return 0;
168
169 erofs_err(sb, "compression disabled, unable to mount compressed EROFS");
170 return -EOPNOTSUPP;
171}
172#endif
173
174static int erofs_init_device(struct erofs_buf *buf, struct super_block *sb,
175 struct erofs_device_info *dif, erofs_off_t *pos)
176{
177 struct erofs_sb_info *sbi = EROFS_SB(sb);
178 struct erofs_fscache *fscache;
179 struct erofs_deviceslot *dis;
180 struct file *bdev_file;
181 void *ptr;
182
183 ptr = erofs_read_metabuf(buf, sb, erofs_blknr(sb, *pos), type: EROFS_KMAP);
184 if (IS_ERR(ptr))
185 return PTR_ERR(ptr);
186 dis = ptr + erofs_blkoff(sb, *pos);
187
188 if (!sbi->devs->flatdev && !dif->path) {
189 if (!dis->tag[0]) {
190 erofs_err(sb, "empty device tag @ pos %llu", *pos);
191 return -EINVAL;
192 }
193 dif->path = kmemdup_nul(s: dis->tag, len: sizeof(dis->tag), GFP_KERNEL);
194 if (!dif->path)
195 return -ENOMEM;
196 }
197
198 if (erofs_is_fscache_mode(sb)) {
199 fscache = erofs_fscache_register_cookie(sb, name: dif->path, flags: 0);
200 if (IS_ERR(ptr: fscache))
201 return PTR_ERR(ptr: fscache);
202 dif->fscache = fscache;
203 } else if (!sbi->devs->flatdev) {
204 bdev_file = bdev_file_open_by_path(path: dif->path, BLK_OPEN_READ,
205 holder: sb->s_type, NULL);
206 if (IS_ERR(ptr: bdev_file))
207 return PTR_ERR(ptr: bdev_file);
208 dif->bdev_file = bdev_file;
209 dif->dax_dev = fs_dax_get_by_bdev(bdev: file_bdev(bdev_file),
210 start_off: &dif->dax_part_off, NULL, NULL);
211 }
212
213 dif->blocks = le32_to_cpu(dis->blocks);
214 dif->mapped_blkaddr = le32_to_cpu(dis->mapped_blkaddr);
215 sbi->total_blocks += dif->blocks;
216 *pos += EROFS_DEVT_SLOT_SIZE;
217 return 0;
218}
219
220static int erofs_scan_devices(struct super_block *sb,
221 struct erofs_super_block *dsb)
222{
223 struct erofs_sb_info *sbi = EROFS_SB(sb);
224 unsigned int ondisk_extradevs;
225 erofs_off_t pos;
226 struct erofs_buf buf = __EROFS_BUF_INITIALIZER;
227 struct erofs_device_info *dif;
228 int id, err = 0;
229
230 sbi->total_blocks = sbi->primarydevice_blocks;
231 if (!erofs_sb_has_device_table(sbi))
232 ondisk_extradevs = 0;
233 else
234 ondisk_extradevs = le16_to_cpu(dsb->extra_devices);
235
236 if (sbi->devs->extra_devices &&
237 ondisk_extradevs != sbi->devs->extra_devices) {
238 erofs_err(sb, "extra devices don't match (ondisk %u, given %u)",
239 ondisk_extradevs, sbi->devs->extra_devices);
240 return -EINVAL;
241 }
242 if (!ondisk_extradevs)
243 return 0;
244
245 if (!sbi->devs->extra_devices && !erofs_is_fscache_mode(sb))
246 sbi->devs->flatdev = true;
247
248 sbi->device_id_mask = roundup_pow_of_two(ondisk_extradevs + 1) - 1;
249 pos = le16_to_cpu(dsb->devt_slotoff) * EROFS_DEVT_SLOT_SIZE;
250 down_read(sem: &sbi->devs->rwsem);
251 if (sbi->devs->extra_devices) {
252 idr_for_each_entry(&sbi->devs->tree, dif, id) {
253 err = erofs_init_device(buf: &buf, sb, dif, pos: &pos);
254 if (err)
255 break;
256 }
257 } else {
258 for (id = 0; id < ondisk_extradevs; id++) {
259 dif = kzalloc(size: sizeof(*dif), GFP_KERNEL);
260 if (!dif) {
261 err = -ENOMEM;
262 break;
263 }
264
265 err = idr_alloc(&sbi->devs->tree, ptr: dif, start: 0, end: 0, GFP_KERNEL);
266 if (err < 0) {
267 kfree(objp: dif);
268 break;
269 }
270 ++sbi->devs->extra_devices;
271
272 err = erofs_init_device(buf: &buf, sb, dif, pos: &pos);
273 if (err)
274 break;
275 }
276 }
277 up_read(sem: &sbi->devs->rwsem);
278 erofs_put_metabuf(buf: &buf);
279 return err;
280}
281
282static int erofs_read_superblock(struct super_block *sb)
283{
284 struct erofs_sb_info *sbi;
285 struct erofs_buf buf = __EROFS_BUF_INITIALIZER;
286 struct erofs_super_block *dsb;
287 void *data;
288 int ret;
289
290 data = erofs_read_metabuf(buf: &buf, sb, blkaddr: 0, type: EROFS_KMAP);
291 if (IS_ERR(ptr: data)) {
292 erofs_err(sb, "cannot read erofs superblock");
293 return PTR_ERR(ptr: data);
294 }
295
296 sbi = EROFS_SB(sb);
297 dsb = (struct erofs_super_block *)(data + EROFS_SUPER_OFFSET);
298
299 ret = -EINVAL;
300 if (le32_to_cpu(dsb->magic) != EROFS_SUPER_MAGIC_V1) {
301 erofs_err(sb, "cannot find valid erofs superblock");
302 goto out;
303 }
304
305 sbi->blkszbits = dsb->blkszbits;
306 if (sbi->blkszbits < 9 || sbi->blkszbits > PAGE_SHIFT) {
307 erofs_err(sb, "blkszbits %u isn't supported", sbi->blkszbits);
308 goto out;
309 }
310 if (dsb->dirblkbits) {
311 erofs_err(sb, "dirblkbits %u isn't supported", dsb->dirblkbits);
312 goto out;
313 }
314
315 sbi->feature_compat = le32_to_cpu(dsb->feature_compat);
316 if (erofs_sb_has_sb_chksum(sbi)) {
317 ret = erofs_superblock_csum_verify(sb, sbdata: data);
318 if (ret)
319 goto out;
320 }
321
322 ret = -EINVAL;
323 if (!check_layout_compatibility(sb, dsb))
324 goto out;
325
326 sbi->sb_size = 128 + dsb->sb_extslots * EROFS_SB_EXTSLOT_SIZE;
327 if (sbi->sb_size > PAGE_SIZE - EROFS_SUPER_OFFSET) {
328 erofs_err(sb, "invalid sb_extslots %u (more than a fs block)",
329 sbi->sb_size);
330 goto out;
331 }
332 sbi->primarydevice_blocks = le32_to_cpu(dsb->blocks);
333 sbi->meta_blkaddr = le32_to_cpu(dsb->meta_blkaddr);
334#ifdef CONFIG_EROFS_FS_XATTR
335 sbi->xattr_blkaddr = le32_to_cpu(dsb->xattr_blkaddr);
336 sbi->xattr_prefix_start = le32_to_cpu(dsb->xattr_prefix_start);
337 sbi->xattr_prefix_count = dsb->xattr_prefix_count;
338 sbi->xattr_filter_reserved = dsb->xattr_filter_reserved;
339#endif
340 sbi->islotbits = ilog2(sizeof(struct erofs_inode_compact));
341 sbi->root_nid = le16_to_cpu(dsb->root_nid);
342 sbi->packed_nid = le64_to_cpu(dsb->packed_nid);
343 sbi->inos = le64_to_cpu(dsb->inos);
344
345 sbi->build_time = le64_to_cpu(dsb->build_time);
346 sbi->build_time_nsec = le32_to_cpu(dsb->build_time_nsec);
347
348 memcpy(&sb->s_uuid, dsb->uuid, sizeof(dsb->uuid));
349
350 ret = strscpy(sbi->volume_name, dsb->volume_name,
351 sizeof(dsb->volume_name));
352 if (ret < 0) { /* -E2BIG */
353 erofs_err(sb, "bad volume name without NIL terminator");
354 ret = -EFSCORRUPTED;
355 goto out;
356 }
357
358 /* parse on-disk compression configurations */
359 ret = z_erofs_parse_cfgs(sb, dsb);
360 if (ret < 0)
361 goto out;
362
363 /* handle multiple devices */
364 ret = erofs_scan_devices(sb, dsb);
365
366 if (erofs_is_fscache_mode(sb))
367 erofs_info(sb, "EXPERIMENTAL fscache-based on-demand read feature in use. Use at your own risk!");
368out:
369 erofs_put_metabuf(buf: &buf);
370 return ret;
371}
372
373static void erofs_default_options(struct erofs_fs_context *ctx)
374{
375#ifdef CONFIG_EROFS_FS_ZIP
376 ctx->opt.cache_strategy = EROFS_ZIP_CACHE_READAROUND;
377 ctx->opt.max_sync_decompress_pages = 3;
378 ctx->opt.sync_decompress = EROFS_SYNC_DECOMPRESS_AUTO;
379#endif
380#ifdef CONFIG_EROFS_FS_XATTR
381 set_opt(&ctx->opt, XATTR_USER);
382#endif
383#ifdef CONFIG_EROFS_FS_POSIX_ACL
384 set_opt(&ctx->opt, POSIX_ACL);
385#endif
386}
387
388enum {
389 Opt_user_xattr,
390 Opt_acl,
391 Opt_cache_strategy,
392 Opt_dax,
393 Opt_dax_enum,
394 Opt_device,
395 Opt_fsid,
396 Opt_domain_id,
397 Opt_err
398};
399
400static const struct constant_table erofs_param_cache_strategy[] = {
401 {"disabled", EROFS_ZIP_CACHE_DISABLED},
402 {"readahead", EROFS_ZIP_CACHE_READAHEAD},
403 {"readaround", EROFS_ZIP_CACHE_READAROUND},
404 {}
405};
406
407static const struct constant_table erofs_dax_param_enums[] = {
408 {"always", EROFS_MOUNT_DAX_ALWAYS},
409 {"never", EROFS_MOUNT_DAX_NEVER},
410 {}
411};
412
413static const struct fs_parameter_spec erofs_fs_parameters[] = {
414 fsparam_flag_no("user_xattr", Opt_user_xattr),
415 fsparam_flag_no("acl", Opt_acl),
416 fsparam_enum("cache_strategy", Opt_cache_strategy,
417 erofs_param_cache_strategy),
418 fsparam_flag("dax", Opt_dax),
419 fsparam_enum("dax", Opt_dax_enum, erofs_dax_param_enums),
420 fsparam_string("device", Opt_device),
421 fsparam_string("fsid", Opt_fsid),
422 fsparam_string("domain_id", Opt_domain_id),
423 {}
424};
425
426static bool erofs_fc_set_dax_mode(struct fs_context *fc, unsigned int mode)
427{
428#ifdef CONFIG_FS_DAX
429 struct erofs_fs_context *ctx = fc->fs_private;
430
431 switch (mode) {
432 case EROFS_MOUNT_DAX_ALWAYS:
433 set_opt(&ctx->opt, DAX_ALWAYS);
434 clear_opt(&ctx->opt, DAX_NEVER);
435 return true;
436 case EROFS_MOUNT_DAX_NEVER:
437 set_opt(&ctx->opt, DAX_NEVER);
438 clear_opt(&ctx->opt, DAX_ALWAYS);
439 return true;
440 default:
441 DBG_BUGON(1);
442 return false;
443 }
444#else
445 errorfc(fc, "dax options not supported");
446 return false;
447#endif
448}
449
450static int erofs_fc_parse_param(struct fs_context *fc,
451 struct fs_parameter *param)
452{
453 struct erofs_fs_context *ctx = fc->fs_private;
454 struct fs_parse_result result;
455 struct erofs_device_info *dif;
456 int opt, ret;
457
458 opt = fs_parse(fc, desc: erofs_fs_parameters, param, result: &result);
459 if (opt < 0)
460 return opt;
461
462 switch (opt) {
463 case Opt_user_xattr:
464#ifdef CONFIG_EROFS_FS_XATTR
465 if (result.boolean)
466 set_opt(&ctx->opt, XATTR_USER);
467 else
468 clear_opt(&ctx->opt, XATTR_USER);
469#else
470 errorfc(fc, "{,no}user_xattr options not supported");
471#endif
472 break;
473 case Opt_acl:
474#ifdef CONFIG_EROFS_FS_POSIX_ACL
475 if (result.boolean)
476 set_opt(&ctx->opt, POSIX_ACL);
477 else
478 clear_opt(&ctx->opt, POSIX_ACL);
479#else
480 errorfc(fc, "{,no}acl options not supported");
481#endif
482 break;
483 case Opt_cache_strategy:
484#ifdef CONFIG_EROFS_FS_ZIP
485 ctx->opt.cache_strategy = result.uint_32;
486#else
487 errorfc(fc, "compression not supported, cache_strategy ignored");
488#endif
489 break;
490 case Opt_dax:
491 if (!erofs_fc_set_dax_mode(fc, EROFS_MOUNT_DAX_ALWAYS))
492 return -EINVAL;
493 break;
494 case Opt_dax_enum:
495 if (!erofs_fc_set_dax_mode(fc, mode: result.uint_32))
496 return -EINVAL;
497 break;
498 case Opt_device:
499 dif = kzalloc(size: sizeof(*dif), GFP_KERNEL);
500 if (!dif)
501 return -ENOMEM;
502 dif->path = kstrdup(s: param->string, GFP_KERNEL);
503 if (!dif->path) {
504 kfree(objp: dif);
505 return -ENOMEM;
506 }
507 down_write(sem: &ctx->devs->rwsem);
508 ret = idr_alloc(&ctx->devs->tree, ptr: dif, start: 0, end: 0, GFP_KERNEL);
509 up_write(sem: &ctx->devs->rwsem);
510 if (ret < 0) {
511 kfree(objp: dif->path);
512 kfree(objp: dif);
513 return ret;
514 }
515 ++ctx->devs->extra_devices;
516 break;
517#ifdef CONFIG_EROFS_FS_ONDEMAND
518 case Opt_fsid:
519 kfree(objp: ctx->fsid);
520 ctx->fsid = kstrdup(s: param->string, GFP_KERNEL);
521 if (!ctx->fsid)
522 return -ENOMEM;
523 break;
524 case Opt_domain_id:
525 kfree(objp: ctx->domain_id);
526 ctx->domain_id = kstrdup(s: param->string, GFP_KERNEL);
527 if (!ctx->domain_id)
528 return -ENOMEM;
529 break;
530#else
531 case Opt_fsid:
532 case Opt_domain_id:
533 errorfc(fc, "%s option not supported", erofs_fs_parameters[opt].name);
534 break;
535#endif
536 default:
537 return -ENOPARAM;
538 }
539 return 0;
540}
541
542static struct inode *erofs_nfs_get_inode(struct super_block *sb,
543 u64 ino, u32 generation)
544{
545 return erofs_iget(sb, nid: ino);
546}
547
548static struct dentry *erofs_fh_to_dentry(struct super_block *sb,
549 struct fid *fid, int fh_len, int fh_type)
550{
551 return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
552 get_inode: erofs_nfs_get_inode);
553}
554
555static struct dentry *erofs_fh_to_parent(struct super_block *sb,
556 struct fid *fid, int fh_len, int fh_type)
557{
558 return generic_fh_to_parent(sb, fid, fh_len, fh_type,
559 get_inode: erofs_nfs_get_inode);
560}
561
562static struct dentry *erofs_get_parent(struct dentry *child)
563{
564 erofs_nid_t nid;
565 unsigned int d_type;
566 int err;
567
568 err = erofs_namei(dir: d_inode(dentry: child), name: &dotdot_name, nid: &nid, d_type: &d_type);
569 if (err)
570 return ERR_PTR(error: err);
571 return d_obtain_alias(erofs_iget(sb: child->d_sb, nid));
572}
573
574static const struct export_operations erofs_export_ops = {
575 .encode_fh = generic_encode_ino32_fh,
576 .fh_to_dentry = erofs_fh_to_dentry,
577 .fh_to_parent = erofs_fh_to_parent,
578 .get_parent = erofs_get_parent,
579};
580
581static int erofs_fc_fill_super(struct super_block *sb, struct fs_context *fc)
582{
583 struct inode *inode;
584 struct erofs_sb_info *sbi;
585 struct erofs_fs_context *ctx = fc->fs_private;
586 int err;
587
588 sb->s_magic = EROFS_SUPER_MAGIC;
589 sb->s_flags |= SB_RDONLY | SB_NOATIME;
590 sb->s_maxbytes = MAX_LFS_FILESIZE;
591 sb->s_op = &erofs_sops;
592
593 sbi = kzalloc(size: sizeof(*sbi), GFP_KERNEL);
594 if (!sbi)
595 return -ENOMEM;
596
597 sb->s_fs_info = sbi;
598 sbi->opt = ctx->opt;
599 sbi->devs = ctx->devs;
600 ctx->devs = NULL;
601 sbi->fsid = ctx->fsid;
602 ctx->fsid = NULL;
603 sbi->domain_id = ctx->domain_id;
604 ctx->domain_id = NULL;
605
606 sbi->blkszbits = PAGE_SHIFT;
607 if (erofs_is_fscache_mode(sb)) {
608 sb->s_blocksize = PAGE_SIZE;
609 sb->s_blocksize_bits = PAGE_SHIFT;
610
611 err = erofs_fscache_register_fs(sb);
612 if (err)
613 return err;
614
615 err = super_setup_bdi(sb);
616 if (err)
617 return err;
618 } else {
619 if (!sb_set_blocksize(sb, PAGE_SIZE)) {
620 errorfc(fc, "failed to set initial blksize");
621 return -EINVAL;
622 }
623
624 sbi->dax_dev = fs_dax_get_by_bdev(bdev: sb->s_bdev,
625 start_off: &sbi->dax_part_off,
626 NULL, NULL);
627 }
628
629 err = erofs_read_superblock(sb);
630 if (err)
631 return err;
632
633 if (sb->s_blocksize_bits != sbi->blkszbits) {
634 if (erofs_is_fscache_mode(sb)) {
635 errorfc(fc, "unsupported blksize for fscache mode");
636 return -EINVAL;
637 }
638 if (!sb_set_blocksize(sb, 1 << sbi->blkszbits)) {
639 errorfc(fc, "failed to set erofs blksize");
640 return -EINVAL;
641 }
642 }
643
644 if (test_opt(&sbi->opt, DAX_ALWAYS)) {
645 if (!sbi->dax_dev) {
646 errorfc(fc, "DAX unsupported by block device. Turning off DAX.");
647 clear_opt(&sbi->opt, DAX_ALWAYS);
648 } else if (sbi->blkszbits != PAGE_SHIFT) {
649 errorfc(fc, "unsupported blocksize for DAX");
650 clear_opt(&sbi->opt, DAX_ALWAYS);
651 }
652 }
653
654 sb->s_time_gran = 1;
655 sb->s_xattr = erofs_xattr_handlers;
656 sb->s_export_op = &erofs_export_ops;
657
658 if (test_opt(&sbi->opt, POSIX_ACL))
659 sb->s_flags |= SB_POSIXACL;
660 else
661 sb->s_flags &= ~SB_POSIXACL;
662
663#ifdef CONFIG_EROFS_FS_ZIP
664 xa_init(xa: &sbi->managed_pslots);
665#endif
666
667 inode = erofs_iget(sb, nid: sbi->root_nid);
668 if (IS_ERR(ptr: inode))
669 return PTR_ERR(ptr: inode);
670
671 if (!S_ISDIR(inode->i_mode)) {
672 erofs_err(sb, "rootino(nid %llu) is not a directory(i_mode %o)",
673 sbi->root_nid, inode->i_mode);
674 iput(inode);
675 return -EINVAL;
676 }
677
678 sb->s_root = d_make_root(inode);
679 if (!sb->s_root)
680 return -ENOMEM;
681
682 erofs_shrinker_register(sb);
683 if (erofs_sb_has_fragments(sbi) && sbi->packed_nid) {
684 sbi->packed_inode = erofs_iget(sb, nid: sbi->packed_nid);
685 if (IS_ERR(ptr: sbi->packed_inode)) {
686 err = PTR_ERR(ptr: sbi->packed_inode);
687 sbi->packed_inode = NULL;
688 return err;
689 }
690 }
691 err = erofs_init_managed_cache(sb);
692 if (err)
693 return err;
694
695 err = erofs_xattr_prefixes_init(sb);
696 if (err)
697 return err;
698
699 err = erofs_register_sysfs(sb);
700 if (err)
701 return err;
702
703 erofs_info(sb, "mounted with root inode @ nid %llu.", sbi->root_nid);
704 return 0;
705}
706
707static int erofs_fc_get_tree(struct fs_context *fc)
708{
709 struct erofs_fs_context *ctx = fc->fs_private;
710
711 if (IS_ENABLED(CONFIG_EROFS_FS_ONDEMAND) && ctx->fsid)
712 return get_tree_nodev(fc, fill_super: erofs_fc_fill_super);
713
714 return get_tree_bdev(fc, fill_super: erofs_fc_fill_super);
715}
716
717static int erofs_fc_reconfigure(struct fs_context *fc)
718{
719 struct super_block *sb = fc->root->d_sb;
720 struct erofs_sb_info *sbi = EROFS_SB(sb);
721 struct erofs_fs_context *ctx = fc->fs_private;
722
723 DBG_BUGON(!sb_rdonly(sb));
724
725 if (ctx->fsid || ctx->domain_id)
726 erofs_info(sb, "ignoring reconfiguration for fsid|domain_id.");
727
728 if (test_opt(&ctx->opt, POSIX_ACL))
729 fc->sb_flags |= SB_POSIXACL;
730 else
731 fc->sb_flags &= ~SB_POSIXACL;
732
733 sbi->opt = ctx->opt;
734
735 fc->sb_flags |= SB_RDONLY;
736 return 0;
737}
738
739static int erofs_release_device_info(int id, void *ptr, void *data)
740{
741 struct erofs_device_info *dif = ptr;
742
743 fs_put_dax(dax_dev: dif->dax_dev, NULL);
744 if (dif->bdev_file)
745 fput(dif->bdev_file);
746 erofs_fscache_unregister_cookie(fscache: dif->fscache);
747 dif->fscache = NULL;
748 kfree(objp: dif->path);
749 kfree(objp: dif);
750 return 0;
751}
752
753static void erofs_free_dev_context(struct erofs_dev_context *devs)
754{
755 if (!devs)
756 return;
757 idr_for_each(&devs->tree, fn: &erofs_release_device_info, NULL);
758 idr_destroy(&devs->tree);
759 kfree(objp: devs);
760}
761
762static void erofs_fc_free(struct fs_context *fc)
763{
764 struct erofs_fs_context *ctx = fc->fs_private;
765
766 erofs_free_dev_context(devs: ctx->devs);
767 kfree(objp: ctx->fsid);
768 kfree(objp: ctx->domain_id);
769 kfree(objp: ctx);
770}
771
772static const struct fs_context_operations erofs_context_ops = {
773 .parse_param = erofs_fc_parse_param,
774 .get_tree = erofs_fc_get_tree,
775 .reconfigure = erofs_fc_reconfigure,
776 .free = erofs_fc_free,
777};
778
779static int erofs_init_fs_context(struct fs_context *fc)
780{
781 struct erofs_fs_context *ctx;
782
783 ctx = kzalloc(size: sizeof(*ctx), GFP_KERNEL);
784 if (!ctx)
785 return -ENOMEM;
786 ctx->devs = kzalloc(size: sizeof(struct erofs_dev_context), GFP_KERNEL);
787 if (!ctx->devs) {
788 kfree(objp: ctx);
789 return -ENOMEM;
790 }
791 fc->fs_private = ctx;
792
793 idr_init(idr: &ctx->devs->tree);
794 init_rwsem(&ctx->devs->rwsem);
795 erofs_default_options(ctx);
796 fc->ops = &erofs_context_ops;
797 return 0;
798}
799
800static void erofs_kill_sb(struct super_block *sb)
801{
802 struct erofs_sb_info *sbi;
803
804 if (erofs_is_fscache_mode(sb))
805 kill_anon_super(sb);
806 else
807 kill_block_super(sb);
808
809 sbi = EROFS_SB(sb);
810 if (!sbi)
811 return;
812
813 erofs_free_dev_context(devs: sbi->devs);
814 fs_put_dax(dax_dev: sbi->dax_dev, NULL);
815 erofs_fscache_unregister_fs(sb);
816 kfree(objp: sbi->fsid);
817 kfree(objp: sbi->domain_id);
818 kfree(objp: sbi);
819 sb->s_fs_info = NULL;
820}
821
822static void erofs_put_super(struct super_block *sb)
823{
824 struct erofs_sb_info *const sbi = EROFS_SB(sb);
825
826 DBG_BUGON(!sbi);
827
828 erofs_unregister_sysfs(sb);
829 erofs_shrinker_unregister(sb);
830 erofs_xattr_prefixes_cleanup(sb);
831#ifdef CONFIG_EROFS_FS_ZIP
832 iput(sbi->managed_cache);
833 sbi->managed_cache = NULL;
834#endif
835 iput(sbi->packed_inode);
836 sbi->packed_inode = NULL;
837 erofs_free_dev_context(devs: sbi->devs);
838 sbi->devs = NULL;
839 erofs_fscache_unregister_fs(sb);
840}
841
842static struct file_system_type erofs_fs_type = {
843 .owner = THIS_MODULE,
844 .name = "erofs",
845 .init_fs_context = erofs_init_fs_context,
846 .kill_sb = erofs_kill_sb,
847 .fs_flags = FS_REQUIRES_DEV | FS_ALLOW_IDMAP,
848};
849MODULE_ALIAS_FS("erofs");
850
851static int __init erofs_module_init(void)
852{
853 int err;
854
855 erofs_check_ondisk_layout_definitions();
856
857 erofs_inode_cachep = kmem_cache_create(name: "erofs_inode",
858 size: sizeof(struct erofs_inode), align: 0,
859 SLAB_RECLAIM_ACCOUNT | SLAB_ACCOUNT,
860 ctor: erofs_inode_init_once);
861 if (!erofs_inode_cachep)
862 return -ENOMEM;
863
864 err = erofs_init_shrinker();
865 if (err)
866 goto shrinker_err;
867
868 err = z_erofs_lzma_init();
869 if (err)
870 goto lzma_err;
871
872 err = z_erofs_deflate_init();
873 if (err)
874 goto deflate_err;
875
876 erofs_pcpubuf_init();
877 err = z_erofs_init_zip_subsystem();
878 if (err)
879 goto zip_err;
880
881 err = erofs_init_sysfs();
882 if (err)
883 goto sysfs_err;
884
885 err = register_filesystem(&erofs_fs_type);
886 if (err)
887 goto fs_err;
888
889 return 0;
890
891fs_err:
892 erofs_exit_sysfs();
893sysfs_err:
894 z_erofs_exit_zip_subsystem();
895zip_err:
896 z_erofs_deflate_exit();
897deflate_err:
898 z_erofs_lzma_exit();
899lzma_err:
900 erofs_exit_shrinker();
901shrinker_err:
902 kmem_cache_destroy(s: erofs_inode_cachep);
903 return err;
904}
905
906static void __exit erofs_module_exit(void)
907{
908 unregister_filesystem(&erofs_fs_type);
909
910 /* Ensure all RCU free inodes / pclusters are safe to be destroyed. */
911 rcu_barrier();
912
913 erofs_exit_sysfs();
914 z_erofs_exit_zip_subsystem();
915 z_erofs_deflate_exit();
916 z_erofs_lzma_exit();
917 erofs_exit_shrinker();
918 kmem_cache_destroy(s: erofs_inode_cachep);
919 erofs_pcpubuf_exit();
920}
921
922static int erofs_statfs(struct dentry *dentry, struct kstatfs *buf)
923{
924 struct super_block *sb = dentry->d_sb;
925 struct erofs_sb_info *sbi = EROFS_SB(sb);
926 u64 id = 0;
927
928 if (!erofs_is_fscache_mode(sb))
929 id = huge_encode_dev(dev: sb->s_bdev->bd_dev);
930
931 buf->f_type = sb->s_magic;
932 buf->f_bsize = sb->s_blocksize;
933 buf->f_blocks = sbi->total_blocks;
934 buf->f_bfree = buf->f_bavail = 0;
935
936 buf->f_files = ULLONG_MAX;
937 buf->f_ffree = ULLONG_MAX - sbi->inos;
938
939 buf->f_namelen = EROFS_NAME_LEN;
940
941 buf->f_fsid = u64_to_fsid(v: id);
942 return 0;
943}
944
945static int erofs_show_options(struct seq_file *seq, struct dentry *root)
946{
947 struct erofs_sb_info *sbi = EROFS_SB(root->d_sb);
948 struct erofs_mount_opts *opt = &sbi->opt;
949
950#ifdef CONFIG_EROFS_FS_XATTR
951 if (test_opt(opt, XATTR_USER))
952 seq_puts(m: seq, s: ",user_xattr");
953 else
954 seq_puts(m: seq, s: ",nouser_xattr");
955#endif
956#ifdef CONFIG_EROFS_FS_POSIX_ACL
957 if (test_opt(opt, POSIX_ACL))
958 seq_puts(m: seq, s: ",acl");
959 else
960 seq_puts(m: seq, s: ",noacl");
961#endif
962#ifdef CONFIG_EROFS_FS_ZIP
963 if (opt->cache_strategy == EROFS_ZIP_CACHE_DISABLED)
964 seq_puts(m: seq, s: ",cache_strategy=disabled");
965 else if (opt->cache_strategy == EROFS_ZIP_CACHE_READAHEAD)
966 seq_puts(m: seq, s: ",cache_strategy=readahead");
967 else if (opt->cache_strategy == EROFS_ZIP_CACHE_READAROUND)
968 seq_puts(m: seq, s: ",cache_strategy=readaround");
969#endif
970 if (test_opt(opt, DAX_ALWAYS))
971 seq_puts(m: seq, s: ",dax=always");
972 if (test_opt(opt, DAX_NEVER))
973 seq_puts(m: seq, s: ",dax=never");
974#ifdef CONFIG_EROFS_FS_ONDEMAND
975 if (sbi->fsid)
976 seq_printf(m: seq, fmt: ",fsid=%s", sbi->fsid);
977 if (sbi->domain_id)
978 seq_printf(m: seq, fmt: ",domain_id=%s", sbi->domain_id);
979#endif
980 return 0;
981}
982
983const struct super_operations erofs_sops = {
984 .put_super = erofs_put_super,
985 .alloc_inode = erofs_alloc_inode,
986 .free_inode = erofs_free_inode,
987 .statfs = erofs_statfs,
988 .show_options = erofs_show_options,
989};
990
991module_init(erofs_module_init);
992module_exit(erofs_module_exit);
993
994MODULE_DESCRIPTION("Enhanced ROM File System");
995MODULE_AUTHOR("Gao Xiang, Chao Yu, Miao Xie, CONSUMER BG, HUAWEI Inc.");
996MODULE_LICENSE("GPL");
997

source code of linux/fs/erofs/super.c