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(sbdata + EROFS_SUPER_OFFSET, 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(~0, dsb, len);
71	kfree(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, 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(inode->i_link);
107	kfree(vi->xattr_shared_xattrs);
108	kmem_cache_free(erofs_inode_cachep, 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, *offset, EROFS_KMAP);
136	if (IS_ERR(ptr))
137		return ptr;
138
139	len = le16_to_cpu(*(__le16 *)ptr);
140	if (!len)
141		len = U16_MAX + 1;
142	buffer = kmalloc(len, GFP_KERNEL);
143	if (!buffer)
144		return ERR_PTR(-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, *offset, EROFS_KMAP);
152		if (IS_ERR(ptr)) {
153			kfree(buffer);
154			return ptr;
155		}
156		memcpy(buffer + i, ptr, 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
182	dis = erofs_read_metabuf(buf, sb, *pos, EROFS_KMAP);
183	if (IS_ERR(dis))
184		return PTR_ERR(dis);
185
186	if (!sbi->devs->flatdev && !dif->path) {
187		if (!dis->tag[0]) {
188			erofs_err(sb, "empty device tag @ pos %llu", *pos);
189			return -EINVAL;
190		}
191		dif->path = kmemdup_nul(dis->tag, sizeof(dis->tag), GFP_KERNEL);
192		if (!dif->path)
193			return -ENOMEM;
194	}
195
196	if (erofs_is_fscache_mode(sb)) {
197		fscache = erofs_fscache_register_cookie(sb, dif->path, 0);
198		if (IS_ERR(fscache))
199			return PTR_ERR(fscache);
200		dif->fscache = fscache;
201	} else if (!sbi->devs->flatdev) {
202		bdev_file = bdev_file_open_by_path(dif->path, BLK_OPEN_READ,
203						sb->s_type, NULL);
204		if (IS_ERR(bdev_file))
205			return PTR_ERR(bdev_file);
206		dif->bdev_file = bdev_file;
207		dif->dax_dev = fs_dax_get_by_bdev(file_bdev(bdev_file),
208				&dif->dax_part_off, NULL, NULL);
209	}
210
211	dif->blocks = le32_to_cpu(dis->blocks);
212	dif->mapped_blkaddr = le32_to_cpu(dis->mapped_blkaddr);
213	sbi->total_blocks += dif->blocks;
214	*pos += EROFS_DEVT_SLOT_SIZE;
215	return 0;
216}
217
218static int erofs_scan_devices(struct super_block *sb,
219			      struct erofs_super_block *dsb)
220{
221	struct erofs_sb_info *sbi = EROFS_SB(sb);
222	unsigned int ondisk_extradevs;
223	erofs_off_t pos;
224	struct erofs_buf buf = __EROFS_BUF_INITIALIZER;
225	struct erofs_device_info *dif;
226	int id, err = 0;
227
228	sbi->total_blocks = sbi->primarydevice_blocks;
229	if (!erofs_sb_has_device_table(sbi))
230		ondisk_extradevs = 0;
231	else
232		ondisk_extradevs = le16_to_cpu(dsb->extra_devices);
233
234	if (sbi->devs->extra_devices &&
235	    ondisk_extradevs != sbi->devs->extra_devices) {
236		erofs_err(sb, "extra devices don't match (ondisk %u, given %u)",
237			  ondisk_extradevs, sbi->devs->extra_devices);
238		return -EINVAL;
239	}
240	if (!ondisk_extradevs)
241		return 0;
242
243	if (!sbi->devs->extra_devices && !erofs_is_fscache_mode(sb))
244		sbi->devs->flatdev = true;
245
246	sbi->device_id_mask = roundup_pow_of_two(ondisk_extradevs + 1) - 1;
247	pos = le16_to_cpu(dsb->devt_slotoff) * EROFS_DEVT_SLOT_SIZE;
248	down_read(&sbi->devs->rwsem);
249	if (sbi->devs->extra_devices) {
250		idr_for_each_entry(&sbi->devs->tree, dif, id) {
251			err = erofs_init_device(&buf, sb, dif, &pos);
252			if (err)
253				break;
254		}
255	} else {
256		for (id = 0; id < ondisk_extradevs; id++) {
257			dif = kzalloc(sizeof(*dif), GFP_KERNEL);
258			if (!dif) {
259				err = -ENOMEM;
260				break;
261			}
262
263			err = idr_alloc(&sbi->devs->tree, dif, 0, 0, GFP_KERNEL);
264			if (err < 0) {
265				kfree(dif);
266				break;
267			}
268			++sbi->devs->extra_devices;
269
270			err = erofs_init_device(&buf, sb, dif, &pos);
271			if (err)
272				break;
273		}
274	}
275	up_read(&sbi->devs->rwsem);
276	erofs_put_metabuf(&buf);
277	return err;
278}
279
280static int erofs_read_superblock(struct super_block *sb)
281{
282	struct erofs_sb_info *sbi;
283	struct erofs_buf buf = __EROFS_BUF_INITIALIZER;
284	struct erofs_super_block *dsb;
285	void *data;
286	int ret;
287
288	data = erofs_read_metabuf(&buf, sb, 0, EROFS_KMAP);
289	if (IS_ERR(data)) {
290		erofs_err(sb, "cannot read erofs superblock");
291		return PTR_ERR(data);
292	}
293
294	sbi = EROFS_SB(sb);
295	dsb = (struct erofs_super_block *)(data + EROFS_SUPER_OFFSET);
296
297	ret = -EINVAL;
298	if (le32_to_cpu(dsb->magic) != EROFS_SUPER_MAGIC_V1) {
299		erofs_err(sb, "cannot find valid erofs superblock");
300		goto out;
301	}
302
303	sbi->blkszbits  = dsb->blkszbits;
304	if (sbi->blkszbits < 9 || sbi->blkszbits > PAGE_SHIFT) {
305		erofs_err(sb, "blkszbits %u isn't supported", sbi->blkszbits);
306		goto out;
307	}
308	if (dsb->dirblkbits) {
309		erofs_err(sb, "dirblkbits %u isn't supported", dsb->dirblkbits);
310		goto out;
311	}
312
313	sbi->feature_compat = le32_to_cpu(dsb->feature_compat);
314	if (erofs_sb_has_sb_chksum(sbi)) {
315		ret = erofs_superblock_csum_verify(sb, data);
316		if (ret)
317			goto out;
318	}
319
320	ret = -EINVAL;
321	if (!check_layout_compatibility(sb, dsb))
322		goto out;
323
324	sbi->sb_size = 128 + dsb->sb_extslots * EROFS_SB_EXTSLOT_SIZE;
325	if (sbi->sb_size > PAGE_SIZE - EROFS_SUPER_OFFSET) {
326		erofs_err(sb, "invalid sb_extslots %u (more than a fs block)",
327			  sbi->sb_size);
328		goto out;
329	}
330	sbi->primarydevice_blocks = le32_to_cpu(dsb->blocks);
331	sbi->meta_blkaddr = le32_to_cpu(dsb->meta_blkaddr);
332#ifdef CONFIG_EROFS_FS_XATTR
333	sbi->xattr_blkaddr = le32_to_cpu(dsb->xattr_blkaddr);
334	sbi->xattr_prefix_start = le32_to_cpu(dsb->xattr_prefix_start);
335	sbi->xattr_prefix_count = dsb->xattr_prefix_count;
336	sbi->xattr_filter_reserved = dsb->xattr_filter_reserved;
337#endif
338	sbi->islotbits = ilog2(sizeof(struct erofs_inode_compact));
339	sbi->root_nid = le16_to_cpu(dsb->root_nid);
340	sbi->packed_nid = le64_to_cpu(dsb->packed_nid);
341	sbi->inos = le64_to_cpu(dsb->inos);
342
343	sbi->build_time = le64_to_cpu(dsb->build_time);
344	sbi->build_time_nsec = le32_to_cpu(dsb->build_time_nsec);
345
346	memcpy(&sb->s_uuid, dsb->uuid, sizeof(dsb->uuid));
347
348	ret = strscpy(sbi->volume_name, dsb->volume_name,
349		      sizeof(dsb->volume_name));
350	if (ret < 0) {	/* -E2BIG */
351		erofs_err(sb, "bad volume name without NIL terminator");
352		ret = -EFSCORRUPTED;
353		goto out;
354	}
355
356	/* parse on-disk compression configurations */
357	ret = z_erofs_parse_cfgs(sb, dsb);
358	if (ret < 0)
359		goto out;
360
361	/* handle multiple devices */
362	ret = erofs_scan_devices(sb, dsb);
363
364	if (erofs_is_fscache_mode(sb))
365		erofs_info(sb, "EXPERIMENTAL fscache-based on-demand read feature in use. Use at your own risk!");
366out:
367	erofs_put_metabuf(&buf);
368	return ret;
369}
370
371static void erofs_default_options(struct erofs_sb_info *sbi)
372{
373#ifdef CONFIG_EROFS_FS_ZIP
374	sbi->opt.cache_strategy = EROFS_ZIP_CACHE_READAROUND;
375	sbi->opt.max_sync_decompress_pages = 3;
376	sbi->opt.sync_decompress = EROFS_SYNC_DECOMPRESS_AUTO;
377#endif
378#ifdef CONFIG_EROFS_FS_XATTR
379	set_opt(&sbi->opt, XATTR_USER);
380#endif
381#ifdef CONFIG_EROFS_FS_POSIX_ACL
382	set_opt(&sbi->opt, POSIX_ACL);
383#endif
384}
385
386enum {
387	Opt_user_xattr,
388	Opt_acl,
389	Opt_cache_strategy,
390	Opt_dax,
391	Opt_dax_enum,
392	Opt_device,
393	Opt_fsid,
394	Opt_domain_id,
395	Opt_err
396};
397
398static const struct constant_table erofs_param_cache_strategy[] = {
399	{"disabled",	EROFS_ZIP_CACHE_DISABLED},
400	{"readahead",	EROFS_ZIP_CACHE_READAHEAD},
401	{"readaround",	EROFS_ZIP_CACHE_READAROUND},
402	{}
403};
404
405static const struct constant_table erofs_dax_param_enums[] = {
406	{"always",	EROFS_MOUNT_DAX_ALWAYS},
407	{"never",	EROFS_MOUNT_DAX_NEVER},
408	{}
409};
410
411static const struct fs_parameter_spec erofs_fs_parameters[] = {
412	fsparam_flag_no("user_xattr",	Opt_user_xattr),
413	fsparam_flag_no("acl",		Opt_acl),
414	fsparam_enum("cache_strategy",	Opt_cache_strategy,
415		     erofs_param_cache_strategy),
416	fsparam_flag("dax",             Opt_dax),
417	fsparam_enum("dax",		Opt_dax_enum, erofs_dax_param_enums),
418	fsparam_string("device",	Opt_device),
419	fsparam_string("fsid",		Opt_fsid),
420	fsparam_string("domain_id",	Opt_domain_id),
421	{}
422};
423
424static bool erofs_fc_set_dax_mode(struct fs_context *fc, unsigned int mode)
425{
426#ifdef CONFIG_FS_DAX
427	struct erofs_sb_info *sbi = fc->s_fs_info;
428
429	switch (mode) {
430	case EROFS_MOUNT_DAX_ALWAYS:
431		set_opt(&sbi->opt, DAX_ALWAYS);
432		clear_opt(&sbi->opt, DAX_NEVER);
433		return true;
434	case EROFS_MOUNT_DAX_NEVER:
435		set_opt(&sbi->opt, DAX_NEVER);
436		clear_opt(&sbi->opt, DAX_ALWAYS);
437		return true;
438	default:
439		DBG_BUGON(1);
440		return false;
441	}
442#else
443	errorfc(fc, "dax options not supported");
444	return false;
445#endif
446}
447
448static int erofs_fc_parse_param(struct fs_context *fc,
449				struct fs_parameter *param)
450{
451	struct erofs_sb_info *sbi = fc->s_fs_info;
452	struct fs_parse_result result;
453	struct erofs_device_info *dif;
454	int opt, ret;
455
456	opt = fs_parse(fc, erofs_fs_parameters, param, &result);
457	if (opt < 0)
458		return opt;
459
460	switch (opt) {
461	case Opt_user_xattr:
462#ifdef CONFIG_EROFS_FS_XATTR
463		if (result.boolean)
464			set_opt(&sbi->opt, XATTR_USER);
465		else
466			clear_opt(&sbi->opt, XATTR_USER);
467#else
468		errorfc(fc, "{,no}user_xattr options not supported");
469#endif
470		break;
471	case Opt_acl:
472#ifdef CONFIG_EROFS_FS_POSIX_ACL
473		if (result.boolean)
474			set_opt(&sbi->opt, POSIX_ACL);
475		else
476			clear_opt(&sbi->opt, POSIX_ACL);
477#else
478		errorfc(fc, "{,no}acl options not supported");
479#endif
480		break;
481	case Opt_cache_strategy:
482#ifdef CONFIG_EROFS_FS_ZIP
483		sbi->opt.cache_strategy = result.uint_32;
484#else
485		errorfc(fc, "compression not supported, cache_strategy ignored");
486#endif
487		break;
488	case Opt_dax:
489		if (!erofs_fc_set_dax_mode(fc, EROFS_MOUNT_DAX_ALWAYS))
490			return -EINVAL;
491		break;
492	case Opt_dax_enum:
493		if (!erofs_fc_set_dax_mode(fc, result.uint_32))
494			return -EINVAL;
495		break;
496	case Opt_device:
497		dif = kzalloc(sizeof(*dif), GFP_KERNEL);
498		if (!dif)
499			return -ENOMEM;
500		dif->path = kstrdup(param->string, GFP_KERNEL);
501		if (!dif->path) {
502			kfree(dif);
503			return -ENOMEM;
504		}
505		down_write(&sbi->devs->rwsem);
506		ret = idr_alloc(&sbi->devs->tree, dif, 0, 0, GFP_KERNEL);
507		up_write(&sbi->devs->rwsem);
508		if (ret < 0) {
509			kfree(dif->path);
510			kfree(dif);
511			return ret;
512		}
513		++sbi->devs->extra_devices;
514		break;
515#ifdef CONFIG_EROFS_FS_ONDEMAND
516	case Opt_fsid:
517		kfree(sbi->fsid);
518		sbi->fsid = kstrdup(param->string, GFP_KERNEL);
519		if (!sbi->fsid)
520			return -ENOMEM;
521		break;
522	case Opt_domain_id:
523		kfree(sbi->domain_id);
524		sbi->domain_id = kstrdup(param->string, GFP_KERNEL);
525		if (!sbi->domain_id)
526			return -ENOMEM;
527		break;
528#else
529	case Opt_fsid:
530	case Opt_domain_id:
531		errorfc(fc, "%s option not supported", erofs_fs_parameters[opt].name);
532		break;
533#endif
534	default:
535		return -ENOPARAM;
536	}
537	return 0;
538}
539
540static struct inode *erofs_nfs_get_inode(struct super_block *sb,
541					 u64 ino, u32 generation)
542{
543	return erofs_iget(sb, ino);
544}
545
546static struct dentry *erofs_fh_to_dentry(struct super_block *sb,
547		struct fid *fid, int fh_len, int fh_type)
548{
549	return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
550				    erofs_nfs_get_inode);
551}
552
553static struct dentry *erofs_fh_to_parent(struct super_block *sb,
554		struct fid *fid, int fh_len, int fh_type)
555{
556	return generic_fh_to_parent(sb, fid, fh_len, fh_type,
557				    erofs_nfs_get_inode);
558}
559
560static struct dentry *erofs_get_parent(struct dentry *child)
561{
562	erofs_nid_t nid;
563	unsigned int d_type;
564	int err;
565
566	err = erofs_namei(d_inode(child), &dotdot_name, &nid, &d_type);
567	if (err)
568		return ERR_PTR(err);
569	return d_obtain_alias(erofs_iget(child->d_sb, nid));
570}
571
572static const struct export_operations erofs_export_ops = {
573	.encode_fh = generic_encode_ino32_fh,
574	.fh_to_dentry = erofs_fh_to_dentry,
575	.fh_to_parent = erofs_fh_to_parent,
576	.get_parent = erofs_get_parent,
577};
578
579static int erofs_fc_fill_super(struct super_block *sb, struct fs_context *fc)
580{
581	struct inode *inode;
582	struct erofs_sb_info *sbi = EROFS_SB(sb);
583	int err;
584
585	sb->s_magic = EROFS_SUPER_MAGIC;
586	sb->s_flags |= SB_RDONLY | SB_NOATIME;
587	sb->s_maxbytes = MAX_LFS_FILESIZE;
588	sb->s_op = &erofs_sops;
589
590	sbi->blkszbits = PAGE_SHIFT;
591	if (erofs_is_fscache_mode(sb)) {
592		sb->s_blocksize = PAGE_SIZE;
593		sb->s_blocksize_bits = PAGE_SHIFT;
594
595		err = erofs_fscache_register_fs(sb);
596		if (err)
597			return err;
598
599		err = super_setup_bdi(sb);
600		if (err)
601			return err;
602	} else {
603		if (!sb_set_blocksize(sb, PAGE_SIZE)) {
604			errorfc(fc, "failed to set initial blksize");
605			return -EINVAL;
606		}
607
608		sbi->dax_dev = fs_dax_get_by_bdev(sb->s_bdev,
609						  &sbi->dax_part_off,
610						  NULL, NULL);
611	}
612
613	err = erofs_read_superblock(sb);
614	if (err)
615		return err;
616
617	if (sb->s_blocksize_bits != sbi->blkszbits) {
618		if (erofs_is_fscache_mode(sb)) {
619			errorfc(fc, "unsupported blksize for fscache mode");
620			return -EINVAL;
621		}
622		if (!sb_set_blocksize(sb, 1 << sbi->blkszbits)) {
623			errorfc(fc, "failed to set erofs blksize");
624			return -EINVAL;
625		}
626	}
627
628	if (test_opt(&sbi->opt, DAX_ALWAYS)) {
629		if (!sbi->dax_dev) {
630			errorfc(fc, "DAX unsupported by block device. Turning off DAX.");
631			clear_opt(&sbi->opt, DAX_ALWAYS);
632		} else if (sbi->blkszbits != PAGE_SHIFT) {
633			errorfc(fc, "unsupported blocksize for DAX");
634			clear_opt(&sbi->opt, DAX_ALWAYS);
635		}
636	}
637
638	sb->s_time_gran = 1;
639	sb->s_xattr = erofs_xattr_handlers;
640	sb->s_export_op = &erofs_export_ops;
641
642	if (test_opt(&sbi->opt, POSIX_ACL))
643		sb->s_flags |= SB_POSIXACL;
644	else
645		sb->s_flags &= ~SB_POSIXACL;
646
647#ifdef CONFIG_EROFS_FS_ZIP
648	xa_init(&sbi->managed_pslots);
649#endif
650
651	inode = erofs_iget(sb, sbi->root_nid);
652	if (IS_ERR(inode))
653		return PTR_ERR(inode);
654
655	if (!S_ISDIR(inode->i_mode)) {
656		erofs_err(sb, "rootino(nid %llu) is not a directory(i_mode %o)",
657			  sbi->root_nid, inode->i_mode);
658		iput(inode);
659		return -EINVAL;
660	}
661
662	sb->s_root = d_make_root(inode);
663	if (!sb->s_root)
664		return -ENOMEM;
665
666	erofs_shrinker_register(sb);
667	if (erofs_sb_has_fragments(sbi) && sbi->packed_nid) {
668		sbi->packed_inode = erofs_iget(sb, sbi->packed_nid);
669		if (IS_ERR(sbi->packed_inode)) {
670			err = PTR_ERR(sbi->packed_inode);
671			sbi->packed_inode = NULL;
672			return err;
673		}
674	}
675	err = erofs_init_managed_cache(sb);
676	if (err)
677		return err;
678
679	err = erofs_xattr_prefixes_init(sb);
680	if (err)
681		return err;
682
683	err = erofs_register_sysfs(sb);
684	if (err)
685		return err;
686
687	erofs_info(sb, "mounted with root inode @ nid %llu.", sbi->root_nid);
688	return 0;
689}
690
691static int erofs_fc_get_tree(struct fs_context *fc)
692{
693	struct erofs_sb_info *sbi = fc->s_fs_info;
694
695	if (IS_ENABLED(CONFIG_EROFS_FS_ONDEMAND) && sbi->fsid)
696		return get_tree_nodev(fc, erofs_fc_fill_super);
697
698	return get_tree_bdev(fc, erofs_fc_fill_super);
699}
700
701static int erofs_fc_reconfigure(struct fs_context *fc)
702{
703	struct super_block *sb = fc->root->d_sb;
704	struct erofs_sb_info *sbi = EROFS_SB(sb);
705	struct erofs_sb_info *new_sbi = fc->s_fs_info;
706
707	DBG_BUGON(!sb_rdonly(sb));
708
709	if (new_sbi->fsid || new_sbi->domain_id)
710		erofs_info(sb, "ignoring reconfiguration for fsid|domain_id.");
711
712	if (test_opt(&new_sbi->opt, POSIX_ACL))
713		fc->sb_flags |= SB_POSIXACL;
714	else
715		fc->sb_flags &= ~SB_POSIXACL;
716
717	sbi->opt = new_sbi->opt;
718
719	fc->sb_flags |= SB_RDONLY;
720	return 0;
721}
722
723static int erofs_release_device_info(int id, void *ptr, void *data)
724{
725	struct erofs_device_info *dif = ptr;
726
727	fs_put_dax(dif->dax_dev, NULL);
728	if (dif->bdev_file)
729		fput(dif->bdev_file);
730	erofs_fscache_unregister_cookie(dif->fscache);
731	dif->fscache = NULL;
732	kfree(dif->path);
733	kfree(dif);
734	return 0;
735}
736
737static void erofs_free_dev_context(struct erofs_dev_context *devs)
738{
739	if (!devs)
740		return;
741	idr_for_each(&devs->tree, &erofs_release_device_info, NULL);
742	idr_destroy(&devs->tree);
743	kfree(devs);
744}
745
746static void erofs_fc_free(struct fs_context *fc)
747{
748	struct erofs_sb_info *sbi = fc->s_fs_info;
749
750	if (!sbi)
751		return;
752
753	erofs_free_dev_context(sbi->devs);
754	kfree(sbi->fsid);
755	kfree(sbi->domain_id);
756	kfree(sbi);
757}
758
759static const struct fs_context_operations erofs_context_ops = {
760	.parse_param	= erofs_fc_parse_param,
761	.get_tree       = erofs_fc_get_tree,
762	.reconfigure    = erofs_fc_reconfigure,
763	.free		= erofs_fc_free,
764};
765
766static int erofs_init_fs_context(struct fs_context *fc)
767{
768	struct erofs_sb_info *sbi;
769
770	sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
771	if (!sbi)
772		return -ENOMEM;
773
774	sbi->devs = kzalloc(sizeof(struct erofs_dev_context), GFP_KERNEL);
775	if (!sbi->devs) {
776		kfree(sbi);
777		return -ENOMEM;
778	}
779	fc->s_fs_info = sbi;
780
781	idr_init(&sbi->devs->tree);
782	init_rwsem(&sbi->devs->rwsem);
783	erofs_default_options(sbi);
784	fc->ops = &erofs_context_ops;
785	return 0;
786}
787
788static void erofs_kill_sb(struct super_block *sb)
789{
790	struct erofs_sb_info *sbi = EROFS_SB(sb);
791
792	if (IS_ENABLED(CONFIG_EROFS_FS_ONDEMAND) && sbi->fsid)
793		kill_anon_super(sb);
794	else
795		kill_block_super(sb);
796
797	erofs_free_dev_context(sbi->devs);
798	fs_put_dax(sbi->dax_dev, NULL);
799	erofs_fscache_unregister_fs(sb);
800	kfree(sbi->fsid);
801	kfree(sbi->domain_id);
802	kfree(sbi);
803	sb->s_fs_info = NULL;
804}
805
806static void erofs_put_super(struct super_block *sb)
807{
808	struct erofs_sb_info *const sbi = EROFS_SB(sb);
809
810	DBG_BUGON(!sbi);
811
812	erofs_unregister_sysfs(sb);
813	erofs_shrinker_unregister(sb);
814	erofs_xattr_prefixes_cleanup(sb);
815#ifdef CONFIG_EROFS_FS_ZIP
816	iput(sbi->managed_cache);
817	sbi->managed_cache = NULL;
818#endif
819	iput(sbi->packed_inode);
820	sbi->packed_inode = NULL;
821	erofs_free_dev_context(sbi->devs);
822	sbi->devs = NULL;
823	erofs_fscache_unregister_fs(sb);
824}
825
826static struct file_system_type erofs_fs_type = {
827	.owner          = THIS_MODULE,
828	.name           = "erofs",
829	.init_fs_context = erofs_init_fs_context,
830	.kill_sb        = erofs_kill_sb,
831	.fs_flags       = FS_REQUIRES_DEV | FS_ALLOW_IDMAP,
832};
833MODULE_ALIAS_FS("erofs");
834
835static int __init erofs_module_init(void)
836{
837	int err;
838
839	erofs_check_ondisk_layout_definitions();
840
841	erofs_inode_cachep = kmem_cache_create("erofs_inode",
842			sizeof(struct erofs_inode), 0,
843			SLAB_RECLAIM_ACCOUNT | SLAB_ACCOUNT,
844			erofs_inode_init_once);
845	if (!erofs_inode_cachep)
846		return -ENOMEM;
847
848	err = erofs_init_shrinker();
849	if (err)
850		goto shrinker_err;
851
852	err = z_erofs_lzma_init();
853	if (err)
854		goto lzma_err;
855
856	err = z_erofs_deflate_init();
857	if (err)
858		goto deflate_err;
859
860	err = z_erofs_zstd_init();
861	if (err)
862		goto zstd_err;
863
864	err = z_erofs_gbuf_init();
865	if (err)
866		goto gbuf_err;
867
868	err = z_erofs_init_zip_subsystem();
869	if (err)
870		goto zip_err;
871
872	err = erofs_init_sysfs();
873	if (err)
874		goto sysfs_err;
875
876	err = register_filesystem(&erofs_fs_type);
877	if (err)
878		goto fs_err;
879
880	return 0;
881
882fs_err:
883	erofs_exit_sysfs();
884sysfs_err:
885	z_erofs_exit_zip_subsystem();
886zip_err:
887	z_erofs_gbuf_exit();
888gbuf_err:
889	z_erofs_zstd_exit();
890zstd_err:
891	z_erofs_deflate_exit();
892deflate_err:
893	z_erofs_lzma_exit();
894lzma_err:
895	erofs_exit_shrinker();
896shrinker_err:
897	kmem_cache_destroy(erofs_inode_cachep);
898	return err;
899}
900
901static void __exit erofs_module_exit(void)
902{
903	unregister_filesystem(&erofs_fs_type);
904
905	/* Ensure all RCU free inodes / pclusters are safe to be destroyed. */
906	rcu_barrier();
907
908	erofs_exit_sysfs();
909	z_erofs_exit_zip_subsystem();
910	z_erofs_zstd_exit();
911	z_erofs_deflate_exit();
912	z_erofs_lzma_exit();
913	erofs_exit_shrinker();
914	kmem_cache_destroy(erofs_inode_cachep);
915	z_erofs_gbuf_exit();
916}
917
918static 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(erofs_is_fscache_mode(sb) ? 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
939static 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#ifdef CONFIG_EROFS_FS_ONDEMAND
957	if (sbi->fsid)
958		seq_printf(seq, ",fsid=%s", sbi->fsid);
959	if (sbi->domain_id)
960		seq_printf(seq, ",domain_id=%s", sbi->domain_id);
961#endif
962	return 0;
963}
964
965const struct super_operations erofs_sops = {
966	.put_super = erofs_put_super,
967	.alloc_inode = erofs_alloc_inode,
968	.free_inode = erofs_free_inode,
969	.statfs = erofs_statfs,
970	.show_options = erofs_show_options,
971};
972
973module_init(erofs_module_init);
974module_exit(erofs_module_exit);
975
976MODULE_DESCRIPTION("Enhanced ROM File System");
977MODULE_AUTHOR("Gao Xiang, Chao Yu, Miao Xie, CONSUMER BG, HUAWEI Inc.");
978MODULE_LICENSE("GPL");
979