[linux-block.git] / fs / erofs / super.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2017-2018 HUAWEI, Inc.
 *             http://www.huawei.com/
 * Created by Gao Xiang <gaoxiang25@huawei.com>
 */
#include <linux/module.h>
#include <linux/buffer_head.h>
#include <linux/statfs.h>
#include <linux/parser.h>
#include <linux/seq_file.h>
#include "xattr.h"

#define CREATE_TRACE_POINTS
#include <trace/events/erofs.h>

static struct kmem_cache *erofs_inode_cachep __read_mostly;

static void erofs_inode_init_once(void *ptr)
{
	struct erofs_inode *vi = ptr;

	inode_init_once(&vi->vfs_inode);
}

static struct inode *erofs_alloc_inode(struct super_block *sb)
{
	struct erofs_inode *vi =
		kmem_cache_alloc(erofs_inode_cachep, GFP_KERNEL);

	if (!vi)
		return NULL;

	/* zero out everything except vfs_inode */
	memset(vi, 0, offsetof(struct erofs_inode, vfs_inode));
	return &vi->vfs_inode;
}

static void erofs_free_inode(struct inode *inode)
{
	struct erofs_inode *vi = EROFS_I(inode);

	/* be careful of RCU symlink path */
	if (inode->i_op == &erofs_fast_symlink_iops)
		kfree(inode->i_link);
	kfree(vi->xattr_shared_xattrs);

	kmem_cache_free(erofs_inode_cachep, vi);
}

static bool check_layout_compatibility(struct super_block *sb,
				       struct erofs_super_block *dsb)
{
	const unsigned int feature = le32_to_cpu(dsb->feature_incompat);

	EROFS_SB(sb)->feature_incompat = feature;

	/* check if current kernel meets all mandatory requirements */
	if (feature & (~EROFS_ALL_FEATURE_INCOMPAT)) {
		errln("unidentified incompatible feature %x, please upgrade kernel version",
		      feature & ~EROFS_ALL_FEATURE_INCOMPAT);
		return false;
	}
	return true;
}

static int erofs_read_superblock(struct super_block *sb)
{
	struct erofs_sb_info *sbi;
	struct buffer_head *bh;
	struct erofs_super_block *dsb;
	unsigned int blkszbits;
	int ret;

	bh = sb_bread(sb, 0);

	if (!bh) {
		errln("cannot read erofs superblock");
		return -EIO;
	}

	sbi = EROFS_SB(sb);
	dsb = (struct erofs_super_block *)(bh->b_data + EROFS_SUPER_OFFSET);

	ret = -EINVAL;
	if (le32_to_cpu(dsb->magic) != EROFS_SUPER_MAGIC_V1) {
		errln("cannot find valid erofs superblock");
		goto out;
	}

	blkszbits = dsb->blkszbits;
	/* 9(512 bytes) + LOG_SECTORS_PER_BLOCK == LOG_BLOCK_SIZE */
	if (blkszbits != LOG_BLOCK_SIZE) {
		errln("blksize %u isn't supported on this platform",
		      1 << blkszbits);
		goto out;
	}

	if (!check_layout_compatibility(sb, dsb))
		goto out;

	sbi->blocks = le32_to_cpu(dsb->blocks);
	sbi->meta_blkaddr = le32_to_cpu(dsb->meta_blkaddr);
#ifdef CONFIG_EROFS_FS_XATTR
	sbi->xattr_blkaddr = le32_to_cpu(dsb->xattr_blkaddr);
#endif
	sbi->islotbits = ilog2(sizeof(struct erofs_inode_compact));
	sbi->root_nid = le16_to_cpu(dsb->root_nid);
	sbi->inos = le64_to_cpu(dsb->inos);

	sbi->build_time = le64_to_cpu(dsb->build_time);
	sbi->build_time_nsec = le32_to_cpu(dsb->build_time_nsec);

	memcpy(&sb->s_uuid, dsb->uuid, sizeof(dsb->uuid));

	ret = strscpy(sbi->volume_name, dsb->volume_name,
		      sizeof(dsb->volume_name));
	if (ret < 0) {	/* -E2BIG */
		errln("bad volume name without NIL terminator");
		ret = -EFSCORRUPTED;
		goto out;
	}
	ret = 0;
out:
	brelse(bh);
	return ret;
}

#ifdef CONFIG_EROFS_FS_ZIP
static int erofs_build_cache_strategy(struct erofs_sb_info *sbi,
				      substring_t *args)
{
	const char *cs = match_strdup(args);
	int err = 0;

	if (!cs) {
		errln("Not enough memory to store cache strategy");
		return -ENOMEM;
	}

	if (!strcmp(cs, "disabled")) {
		sbi->cache_strategy = EROFS_ZIP_CACHE_DISABLED;
	} else if (!strcmp(cs, "readahead")) {
		sbi->cache_strategy = EROFS_ZIP_CACHE_READAHEAD;
	} else if (!strcmp(cs, "readaround")) {
		sbi->cache_strategy = EROFS_ZIP_CACHE_READAROUND;
	} else {
		errln("Unrecognized cache strategy \"%s\"", cs);
		err = -EINVAL;
	}
	kfree(cs);
	return err;
}
#else
static int erofs_build_cache_strategy(struct erofs_sb_info *sbi,
				      substring_t *args)
{
	infoln("EROFS compression is disabled, so cache strategy is ignored");
	return 0;
}
#endif

/* set up default EROFS parameters */
static void erofs_default_options(struct erofs_sb_info *sbi)
{
#ifdef CONFIG_EROFS_FS_ZIP
	sbi->cache_strategy = EROFS_ZIP_CACHE_READAROUND;
	sbi->max_sync_decompress_pages = 3;
#endif
#ifdef CONFIG_EROFS_FS_XATTR
	set_opt(sbi, XATTR_USER);
#endif
#ifdef CONFIG_EROFS_FS_POSIX_ACL
	set_opt(sbi, POSIX_ACL);
#endif
}

enum {
	Opt_user_xattr,
	Opt_nouser_xattr,
	Opt_acl,
	Opt_noacl,
	Opt_cache_strategy,
	Opt_err
};

static match_table_t erofs_tokens = {
	{Opt_user_xattr, "user_xattr"},
	{Opt_nouser_xattr, "nouser_xattr"},
	{Opt_acl, "acl"},
	{Opt_noacl, "noacl"},
	{Opt_cache_strategy, "cache_strategy=%s"},
	{Opt_err, NULL}
};

static int erofs_parse_options(struct super_block *sb, char *options)
{
	substring_t args[MAX_OPT_ARGS];
	char *p;
	int err;

	if (!options)
		return 0;

	while ((p = strsep(&options, ","))) {
		int token;

		if (!*p)
			continue;

		args[0].to = args[0].from = NULL;
		token = match_token(p, erofs_tokens, args);

		switch (token) {
#ifdef CONFIG_EROFS_FS_XATTR
		case Opt_user_xattr:
			set_opt(EROFS_SB(sb), XATTR_USER);
			break;
		case Opt_nouser_xattr:
			clear_opt(EROFS_SB(sb), XATTR_USER);
			break;
#else
		case Opt_user_xattr:
			infoln("user_xattr options not supported");
			break;
		case Opt_nouser_xattr:
			infoln("nouser_xattr options not supported");
			break;
#endif
#ifdef CONFIG_EROFS_FS_POSIX_ACL
		case Opt_acl:
			set_opt(EROFS_SB(sb), POSIX_ACL);
			break;
		case Opt_noacl:
			clear_opt(EROFS_SB(sb), POSIX_ACL);
			break;
#else
		case Opt_acl:
			infoln("acl options not supported");
			break;
		case Opt_noacl:
			infoln("noacl options not supported");
			break;
#endif
		case Opt_cache_strategy:
			err = erofs_build_cache_strategy(EROFS_SB(sb), args);
			if (err)
				return err;
			break;
		default:
			errln("Unrecognized mount option \"%s\" or missing value", p);
			return -EINVAL;
		}
	}
	return 0;
}

#ifdef CONFIG_EROFS_FS_ZIP
static const struct address_space_operations managed_cache_aops;

static int erofs_managed_cache_releasepage(struct page *page, gfp_t gfp_mask)
{
	int ret = 1;	/* 0 - busy */
	struct address_space *const mapping = page->mapping;

	DBG_BUGON(!PageLocked(page));
	DBG_BUGON(mapping->a_ops != &managed_cache_aops);

	if (PagePrivate(page))
		ret = erofs_try_to_free_cached_page(mapping, page);

	return ret;
}

static void erofs_managed_cache_invalidatepage(struct page *page,
					       unsigned int offset,
					       unsigned int length)
{
	const unsigned int stop = length + offset;

	DBG_BUGON(!PageLocked(page));

	/* Check for potential overflow in debug mode */
	DBG_BUGON(stop > PAGE_SIZE || stop < length);

	if (offset == 0 && stop == PAGE_SIZE)
		while (!erofs_managed_cache_releasepage(page, GFP_NOFS))
			cond_resched();
}

static const struct address_space_operations managed_cache_aops = {
	.releasepage = erofs_managed_cache_releasepage,
	.invalidatepage = erofs_managed_cache_invalidatepage,
};

static int erofs_init_managed_cache(struct super_block *sb)
{
	struct erofs_sb_info *const sbi = EROFS_SB(sb);
	struct inode *const inode = new_inode(sb);

	if (!inode)
		return -ENOMEM;

	set_nlink(inode, 1);
	inode->i_size = OFFSET_MAX;

	inode->i_mapping->a_ops = &managed_cache_aops;
	mapping_set_gfp_mask(inode->i_mapping,
			     GFP_NOFS | __GFP_HIGHMEM | __GFP_MOVABLE);
	sbi->managed_cache = inode;
	return 0;
}
#else
static int erofs_init_managed_cache(struct super_block *sb) { return 0; }
#endif

static int erofs_fill_super(struct super_block *sb, void *data, int silent)
{
	struct inode *inode;
	struct erofs_sb_info *sbi;
	int err;

	sb->s_magic = EROFS_SUPER_MAGIC;

	if (!sb_set_blocksize(sb, EROFS_BLKSIZ)) {
		errln("failed to set erofs blksize");
		return -EINVAL;
	}

	sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
	if (!sbi)
		return -ENOMEM;

	sb->s_fs_info = sbi;
	err = erofs_read_superblock(sb);
	if (err)
		return err;

	sb->s_flags |= SB_RDONLY | SB_NOATIME;
	sb->s_maxbytes = MAX_LFS_FILESIZE;
	sb->s_time_gran = 1;

	sb->s_op = &erofs_sops;

#ifdef CONFIG_EROFS_FS_XATTR
	sb->s_xattr = erofs_xattr_handlers;
#endif
	/* set erofs default mount options */
	erofs_default_options(sbi);

	err = erofs_parse_options(sb, data);
	if (err)
		return err;

	if (test_opt(sbi, POSIX_ACL))
		sb->s_flags |= SB_POSIXACL;
	else
		sb->s_flags &= ~SB_POSIXACL;

#ifdef CONFIG_EROFS_FS_ZIP
	INIT_RADIX_TREE(&sbi->workstn_tree, GFP_ATOMIC);
#endif

	/* get the root inode */
	inode = erofs_iget(sb, ROOT_NID(sbi), true);
	if (IS_ERR(inode))
		return PTR_ERR(inode);

	if (!S_ISDIR(inode->i_mode)) {
		errln("rootino(nid %llu) is not a directory(i_mode %o)",
		      ROOT_NID(sbi), inode->i_mode);
		iput(inode);
		return -EINVAL;
	}

	sb->s_root = d_make_root(inode);
	if (!sb->s_root)
		return -ENOMEM;

	erofs_shrinker_register(sb);
	/* sb->s_umount is already locked, SB_ACTIVE and SB_BORN are not set */
	err = erofs_init_managed_cache(sb);
	if (err)
		return err;

	if (!silent)
		infoln("mounted on %s with opts: %s, root inode @ nid %llu.",
		       sb->s_id, (char *)data, ROOT_NID(sbi));
	return 0;
}

static struct dentry *erofs_mount(struct file_system_type *fs_type, int flags,
				  const char *dev_name, void *data)
{
	return mount_bdev(fs_type, flags, dev_name, data, erofs_fill_super);
}

/*
 * could be triggered after deactivate_locked_super()
 * is called, thus including umount and failed to initialize.
 */
static void erofs_kill_sb(struct super_block *sb)
{
	struct erofs_sb_info *sbi;

	WARN_ON(sb->s_magic != EROFS_SUPER_MAGIC);
	infoln("unmounting for %s", sb->s_id);

	kill_block_super(sb);

	sbi = EROFS_SB(sb);
	if (!sbi)
		return;
	kfree(sbi);
	sb->s_fs_info = NULL;
}

/* called when ->s_root is non-NULL */
static void erofs_put_super(struct super_block *sb)
{
	struct erofs_sb_info *const sbi = EROFS_SB(sb);

	DBG_BUGON(!sbi);

	erofs_shrinker_unregister(sb);
#ifdef CONFIG_EROFS_FS_ZIP
	iput(sbi->managed_cache);
	sbi->managed_cache = NULL;
#endif
}

static struct file_system_type erofs_fs_type = {
	.owner          = THIS_MODULE,
	.name           = "erofs",
	.mount          = erofs_mount,
	.kill_sb        = erofs_kill_sb,
	.fs_flags       = FS_REQUIRES_DEV,
};
MODULE_ALIAS_FS("erofs");

static int __init erofs_module_init(void)
{
	int err;

	erofs_check_ondisk_layout_definitions();
	infoln("initializing erofs " EROFS_VERSION);

	erofs_inode_cachep = kmem_cache_create("erofs_inode",
					       sizeof(struct erofs_inode), 0,
					       SLAB_RECLAIM_ACCOUNT,
					       erofs_inode_init_once);
	if (!erofs_inode_cachep) {
		err = -ENOMEM;
		goto icache_err;
	}

	err = erofs_init_shrinker();
	if (err)
		goto shrinker_err;

	err = z_erofs_init_zip_subsystem();
	if (err)
		goto zip_err;

	err = register_filesystem(&erofs_fs_type);
	if (err)
		goto fs_err;

	infoln("successfully to initialize erofs");
	return 0;

fs_err:
	z_erofs_exit_zip_subsystem();
zip_err:
	erofs_exit_shrinker();
shrinker_err:
	kmem_cache_destroy(erofs_inode_cachep);
icache_err:
	return err;
}

static void __exit erofs_module_exit(void)
{
	unregister_filesystem(&erofs_fs_type);
	z_erofs_exit_zip_subsystem();
	erofs_exit_shrinker();

	/* Ensure all RCU free inodes are safe before cache is destroyed. */
	rcu_barrier();
	kmem_cache_destroy(erofs_inode_cachep);
	infoln("successfully finalize erofs");
}

/* get filesystem statistics */
static int erofs_statfs(struct dentry *dentry, struct kstatfs *buf)
{
	struct super_block *sb = dentry->d_sb;
	struct erofs_sb_info *sbi = EROFS_SB(sb);
	u64 id = huge_encode_dev(sb->s_bdev->bd_dev);

	buf->f_type = sb->s_magic;
	buf->f_bsize = EROFS_BLKSIZ;
	buf->f_blocks = sbi->blocks;
	buf->f_bfree = buf->f_bavail = 0;

	buf->f_files = ULLONG_MAX;
	buf->f_ffree = ULLONG_MAX - sbi->inos;

	buf->f_namelen = EROFS_NAME_LEN;

	buf->f_fsid.val[0] = (u32)id;
	buf->f_fsid.val[1] = (u32)(id >> 32);
	return 0;
}

static int erofs_show_options(struct seq_file *seq, struct dentry *root)
{
	struct erofs_sb_info *sbi __maybe_unused = EROFS_SB(root->d_sb);

#ifdef CONFIG_EROFS_FS_XATTR
	if (test_opt(sbi, XATTR_USER))
		seq_puts(seq, ",user_xattr");
	else
		seq_puts(seq, ",nouser_xattr");
#endif
#ifdef CONFIG_EROFS_FS_POSIX_ACL
	if (test_opt(sbi, POSIX_ACL))
		seq_puts(seq, ",acl");
	else
		seq_puts(seq, ",noacl");
#endif
#ifdef CONFIG_EROFS_FS_ZIP
	if (sbi->cache_strategy == EROFS_ZIP_CACHE_DISABLED) {
		seq_puts(seq, ",cache_strategy=disabled");
	} else if (sbi->cache_strategy == EROFS_ZIP_CACHE_READAHEAD) {
		seq_puts(seq, ",cache_strategy=readahead");
	} else if (sbi->cache_strategy == EROFS_ZIP_CACHE_READAROUND) {
		seq_puts(seq, ",cache_strategy=readaround");
	} else {
		seq_puts(seq, ",cache_strategy=(unknown)");
		DBG_BUGON(1);
	}
#endif
	return 0;
}

static int erofs_remount(struct super_block *sb, int *flags, char *data)
{
	struct erofs_sb_info *sbi = EROFS_SB(sb);
	unsigned int org_mnt_opt = sbi->mount_opt;
	int err;

	DBG_BUGON(!sb_rdonly(sb));
	err = erofs_parse_options(sb, data);
	if (err)
		goto out;

	if (test_opt(sbi, POSIX_ACL))
		sb->s_flags |= SB_POSIXACL;
	else
		sb->s_flags &= ~SB_POSIXACL;

	*flags |= SB_RDONLY;
	return 0;
out:
	sbi->mount_opt = org_mnt_opt;
	return err;
}

const struct super_operations erofs_sops = {
	.put_super = erofs_put_super,
	.alloc_inode = erofs_alloc_inode,
	.free_inode = erofs_free_inode,
	.statfs = erofs_statfs,
	.show_options = erofs_show_options,
	.remount_fs = erofs_remount,
};

module_init(erofs_module_init);
module_exit(erofs_module_exit);

MODULE_DESCRIPTION("Enhanced ROM File System");
MODULE_AUTHOR("Gao Xiang, Chao Yu, Miao Xie, CONSUMER BG, HUAWEI Inc.");
MODULE_LICENSE("GPL");
Commit	Line	Data
29b24f6c	1	// SPDX-License-Identifier: GPL-2.0-only
ba2b77a8	2	/*
ba2b77a8 GX	3	* Copyright (C) 2017-2018 HUAWEI, Inc.
	4	* http://www.huawei.com/
	5	* Created by Gao Xiang <gaoxiang25@huawei.com>
ba2b77a8 GX	6	*/
	7	#include <linux/module.h>
	8	#include <linux/buffer_head.h>
	9	#include <linux/statfs.h>
	10	#include <linux/parser.h>
b17500a0	11	#include <linux/seq_file.h>
6af7b483	12	#include "xattr.h"
ba2b77a8	13
13f06f48 CY	14	#define CREATE_TRACE_POINTS
	15	#include <trace/events/erofs.h>
	16
ba2b77a8 GX	17	static struct kmem_cache *erofs_inode_cachep __read_mostly;
ba2b77a8 GX	18
99634bf3	19	static void erofs_inode_init_once(void *ptr)
ba2b77a8	20	{
a5876e24	21	struct erofs_inode *vi = ptr;
ba2b77a8 GX	22
	23	inode_init_once(&vi->vfs_inode);
	24	}
	25
99634bf3	26	static struct inode erofs_alloc_inode(struct super_block sb)
ba2b77a8	27	{
a5876e24	28	struct erofs_inode *vi =
ba2b77a8 GX	29	kmem_cache_alloc(erofs_inode_cachep, GFP_KERNEL);
ba2b77a8 GX	30
e2ff9f15	31	if (!vi)
ba2b77a8 GX	32	return NULL;
	33
	34	/* zero out everything except vfs_inode */
a5876e24	35	memset(vi, 0, offsetof(struct erofs_inode, vfs_inode));
ba2b77a8 GX	36	return &vi->vfs_inode;
	37	}
	38
99634bf3	39	static void erofs_free_inode(struct inode *inode)
ba2b77a8	40	{
a5876e24	41	struct erofs_inode *vi = EROFS_I(inode);
ba2b77a8	42
a2c75c81 GX	43	/* be careful of RCU symlink path */
a2c75c81 GX	44	if (inode->i_op == &erofs_fast_symlink_iops)
ba2b77a8	45	kfree(inode->i_link);
ba2b77a8 GX	46	kfree(vi->xattr_shared_xattrs);
	47
	48	kmem_cache_free(erofs_inode_cachep, vi);
	49	}
	50
5efe5137	51	static bool check_layout_compatibility(struct super_block *sb,
0259f209	52	struct erofs_super_block *dsb)
5efe5137	53	{
0259f209	54	const unsigned int feature = le32_to_cpu(dsb->feature_incompat);
5efe5137	55
426a9308	56	EROFS_SB(sb)->feature_incompat = feature;
5efe5137 GX	57
5efe5137 GX	58	/* check if current kernel meets all mandatory requirements */
426a9308 GX	59	if (feature & (~EROFS_ALL_FEATURE_INCOMPAT)) {
	60	errln("unidentified incompatible feature %x, please upgrade kernel version",
	61	feature & ~EROFS_ALL_FEATURE_INCOMPAT);
5efe5137 GX	62	return false;
	63	}
	64	return true;
	65	}
	66
99634bf3	67	static int erofs_read_superblock(struct super_block *sb)
ba2b77a8 GX	68	{
	69	struct erofs_sb_info *sbi;
	70	struct buffer_head *bh;
0259f209	71	struct erofs_super_block *dsb;
7dd68b14	72	unsigned int blkszbits;
ba2b77a8 GX	73	int ret;
	74
	75	bh = sb_bread(sb, 0);
	76
e2ff9f15	77	if (!bh) {
ba2b77a8 GX	78	errln("cannot read erofs superblock");
	79	return -EIO;
	80	}
	81
	82	sbi = EROFS_SB(sb);
0259f209	83	dsb = (struct erofs_super_block *)(bh->b_data + EROFS_SUPER_OFFSET);
ba2b77a8 GX	84
ba2b77a8 GX	85	ret = -EINVAL;
0259f209	86	if (le32_to_cpu(dsb->magic) != EROFS_SUPER_MAGIC_V1) {
ba2b77a8 GX	87	errln("cannot find valid erofs superblock");
	88	goto out;
	89	}
	90
0259f209	91	blkszbits = dsb->blkszbits;
ba2b77a8	92	/* 9(512 bytes) + LOG_SECTORS_PER_BLOCK == LOG_BLOCK_SIZE */
8d8a09b0	93	if (blkszbits != LOG_BLOCK_SIZE) {
ba2b77a8	94	errln("blksize %u isn't supported on this platform",
447a3621	95	1 << blkszbits);
ba2b77a8 GX	96	goto out;
	97	}
	98
0259f209	99	if (!check_layout_compatibility(sb, dsb))
5efe5137 GX	100	goto out;
5efe5137 GX	101
0259f209 GX	102	sbi->blocks = le32_to_cpu(dsb->blocks);
0259f209 GX	103	sbi->meta_blkaddr = le32_to_cpu(dsb->meta_blkaddr);
b17500a0	104	#ifdef CONFIG_EROFS_FS_XATTR
0259f209	105	sbi->xattr_blkaddr = le32_to_cpu(dsb->xattr_blkaddr);
b17500a0	106	#endif
8a765682	107	sbi->islotbits = ilog2(sizeof(struct erofs_inode_compact));
0259f209 GX	108	sbi->root_nid = le16_to_cpu(dsb->root_nid);
0259f209 GX	109	sbi->inos = le64_to_cpu(dsb->inos);
ba2b77a8	110
0259f209 GX	111	sbi->build_time = le64_to_cpu(dsb->build_time);
0259f209 GX	112	sbi->build_time_nsec = le32_to_cpu(dsb->build_time_nsec);
ba2b77a8	113
0259f209	114	memcpy(&sb->s_uuid, dsb->uuid, sizeof(dsb->uuid));
ba2b77a8	115
0259f209 GX	116	ret = strscpy(sbi->volume_name, dsb->volume_name,
0259f209 GX	117	sizeof(dsb->volume_name));
a64d9493 GX	118	if (ret < 0) { /* -E2BIG */
	119	errln("bad volume name without NIL terminator");
	120	ret = -EFSCORRUPTED;
	121	goto out;
	122	}
ba2b77a8 GX	123	ret = 0;
	124	out:
	125	brelse(bh);
	126	return ret;
	127	}
	128
4279f3f9 GX	129	#ifdef CONFIG_EROFS_FS_ZIP
	130	static int erofs_build_cache_strategy(struct erofs_sb_info *sbi,
	131	substring_t *args)
	132	{
	133	const char *cs = match_strdup(args);
	134	int err = 0;
	135
	136	if (!cs) {
	137	errln("Not enough memory to store cache strategy");
	138	return -ENOMEM;
	139	}
	140
	141	if (!strcmp(cs, "disabled")) {
	142	sbi->cache_strategy = EROFS_ZIP_CACHE_DISABLED;
	143	} else if (!strcmp(cs, "readahead")) {
	144	sbi->cache_strategy = EROFS_ZIP_CACHE_READAHEAD;
	145	} else if (!strcmp(cs, "readaround")) {
	146	sbi->cache_strategy = EROFS_ZIP_CACHE_READAROUND;
	147	} else {
	148	errln("Unrecognized cache strategy \"%s\"", cs);
	149	err = -EINVAL;
	150	}
	151	kfree(cs);
	152	return err;
	153	}
	154	#else
	155	static int erofs_build_cache_strategy(struct erofs_sb_info *sbi,
	156	substring_t *args)
	157	{
	158	infoln("EROFS compression is disabled, so cache strategy is ignored");
	159	return 0;
	160	}
	161	#endif
	162
	163	/* set up default EROFS parameters */
99634bf3	164	static void erofs_default_options(struct erofs_sb_info *sbi)
ba2b77a8	165	{
5fb76bb0	166	#ifdef CONFIG_EROFS_FS_ZIP
4279f3f9	167	sbi->cache_strategy = EROFS_ZIP_CACHE_READAROUND;
14f362b4	168	sbi->max_sync_decompress_pages = 3;
5fb76bb0	169	#endif
b17500a0 GX	170	#ifdef CONFIG_EROFS_FS_XATTR
	171	set_opt(sbi, XATTR_USER);
	172	#endif
b17500a0 GX	173	#ifdef CONFIG_EROFS_FS_POSIX_ACL
	174	set_opt(sbi, POSIX_ACL);
	175	#endif
ba2b77a8 GX	176	}
	177
	178	enum {
b17500a0 GX	179	Opt_user_xattr,
	180	Opt_nouser_xattr,
	181	Opt_acl,
	182	Opt_noacl,
4279f3f9	183	Opt_cache_strategy,
ba2b77a8 GX	184	Opt_err
	185	};
	186
	187	static match_table_t erofs_tokens = {
b17500a0 GX	188	{Opt_user_xattr, "user_xattr"},
	189	{Opt_nouser_xattr, "nouser_xattr"},
	190	{Opt_acl, "acl"},
	191	{Opt_noacl, "noacl"},
4279f3f9	192	{Opt_cache_strategy, "cache_strategy=%s"},
ba2b77a8 GX	193	{Opt_err, NULL}
	194	};
	195
99634bf3	196	static int erofs_parse_options(struct super_block sb, char options)
ba2b77a8 GX	197	{
	198	substring_t args[MAX_OPT_ARGS];
	199	char *p;
01e4ae4b	200	int err;
ba2b77a8 GX	201
	202	if (!options)
	203	return 0;
	204
561fb35a	205	while ((p = strsep(&options, ","))) {
ba2b77a8 GX	206	int token;
	207
	208	if (!*p)
	209	continue;
	210
	211	args[0].to = args[0].from = NULL;
	212	token = match_token(p, erofs_tokens, args);
	213
	214	switch (token) {
b17500a0 GX	215	#ifdef CONFIG_EROFS_FS_XATTR
	216	case Opt_user_xattr:
	217	set_opt(EROFS_SB(sb), XATTR_USER);
	218	break;
	219	case Opt_nouser_xattr:
	220	clear_opt(EROFS_SB(sb), XATTR_USER);
	221	break;
	222	#else
	223	case Opt_user_xattr:
	224	infoln("user_xattr options not supported");
	225	break;
	226	case Opt_nouser_xattr:
	227	infoln("nouser_xattr options not supported");
	228	break;
	229	#endif
	230	#ifdef CONFIG_EROFS_FS_POSIX_ACL
	231	case Opt_acl:
	232	set_opt(EROFS_SB(sb), POSIX_ACL);
	233	break;
	234	case Opt_noacl:
	235	clear_opt(EROFS_SB(sb), POSIX_ACL);
	236	break;
	237	#else
	238	case Opt_acl:
	239	infoln("acl options not supported");
	240	break;
	241	case Opt_noacl:
	242	infoln("noacl options not supported");
	243	break;
	244	#endif
4279f3f9 GX	245	case Opt_cache_strategy:
	246	err = erofs_build_cache_strategy(EROFS_SB(sb), args);
	247	if (err)
	248	return err;
	249	break;
ba2b77a8	250	default:
bc33d9f3	251	errln("Unrecognized mount option \"%s\" or missing value", p);
ba2b77a8 GX	252	return -EINVAL;
	253	}
	254	}
	255	return 0;
	256	}
	257
4279f3f9	258	#ifdef CONFIG_EROFS_FS_ZIP
105d4ad8 GX	259	static const struct address_space_operations managed_cache_aops;
105d4ad8 GX	260
99634bf3	261	static int erofs_managed_cache_releasepage(struct page *page, gfp_t gfp_mask)
105d4ad8 GX	262	{
	263	int ret = 1; /* 0 - busy */
	264	struct address_space *const mapping = page->mapping;
	265
8b987bca GX	266	DBG_BUGON(!PageLocked(page));
8b987bca GX	267	DBG_BUGON(mapping->a_ops != &managed_cache_aops);
105d4ad8 GX	268
105d4ad8 GX	269	if (PagePrivate(page))
47e541a1	270	ret = erofs_try_to_free_cached_page(mapping, page);
105d4ad8 GX	271
	272	return ret;
	273	}
	274
99634bf3 GX	275	static void erofs_managed_cache_invalidatepage(struct page *page,
	276	unsigned int offset,
	277	unsigned int length)
105d4ad8 GX	278	{
	279	const unsigned int stop = length + offset;
	280
8b987bca	281	DBG_BUGON(!PageLocked(page));
105d4ad8	282
8b987bca GX	283	/* Check for potential overflow in debug mode */
8b987bca GX	284	DBG_BUGON(stop > PAGE_SIZE \|\| stop < length);
105d4ad8 GX	285
105d4ad8 GX	286	if (offset == 0 && stop == PAGE_SIZE)
99634bf3	287	while (!erofs_managed_cache_releasepage(page, GFP_NOFS))
105d4ad8 GX	288	cond_resched();
	289	}
	290
	291	static const struct address_space_operations managed_cache_aops = {
99634bf3 GX	292	.releasepage = erofs_managed_cache_releasepage,
99634bf3 GX	293	.invalidatepage = erofs_managed_cache_invalidatepage,
105d4ad8 GX	294	};
105d4ad8 GX	295
8f7acdae	296	static int erofs_init_managed_cache(struct super_block *sb)
105d4ad8	297	{
8f7acdae GX	298	struct erofs_sb_info *const sbi = EROFS_SB(sb);
8f7acdae GX	299	struct inode *const inode = new_inode(sb);
105d4ad8	300
8d8a09b0	301	if (!inode)
8f7acdae	302	return -ENOMEM;
105d4ad8 GX	303
	304	set_nlink(inode, 1);
	305	inode->i_size = OFFSET_MAX;
	306
	307	inode->i_mapping->a_ops = &managed_cache_aops;
	308	mapping_set_gfp_mask(inode->i_mapping,
8494c29f	309	GFP_NOFS \| __GFP_HIGHMEM \| __GFP_MOVABLE);
8f7acdae GX	310	sbi->managed_cache = inode;
8f7acdae GX	311	return 0;
105d4ad8	312	}
8f7acdae GX	313	#else
8f7acdae GX	314	static int erofs_init_managed_cache(struct super_block *sb) { return 0; }
105d4ad8 GX	315	#endif
105d4ad8 GX	316
9e794de5	317	static int erofs_fill_super(struct super_block sb, void data, int silent)
ba2b77a8 GX	318	{
	319	struct inode *inode;
	320	struct erofs_sb_info *sbi;
8f7acdae	321	int err;
ba2b77a8	322
8f7acdae GX	323	sb->s_magic = EROFS_SUPER_MAGIC;
8f7acdae GX	324
8d8a09b0	325	if (!sb_set_blocksize(sb, EROFS_BLKSIZ)) {
ba2b77a8	326	errln("failed to set erofs blksize");
8f7acdae	327	return -EINVAL;
ba2b77a8 GX	328	}
ba2b77a8 GX	329
a9f69bd5	330	sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
8d8a09b0	331	if (!sbi)
8f7acdae	332	return -ENOMEM;
ba2b77a8	333
8f7acdae	334	sb->s_fs_info = sbi;
99634bf3	335	err = erofs_read_superblock(sb);
ba2b77a8	336	if (err)
8f7acdae	337	return err;
ba2b77a8	338
5f0abea6	339	sb->s_flags \|= SB_RDONLY \| SB_NOATIME;
ba2b77a8 GX	340	sb->s_maxbytes = MAX_LFS_FILESIZE;
	341	sb->s_time_gran = 1;
	342
	343	sb->s_op = &erofs_sops;
	344
b17500a0 GX	345	#ifdef CONFIG_EROFS_FS_XATTR
	346	sb->s_xattr = erofs_xattr_handlers;
	347	#endif
ba2b77a8	348	/* set erofs default mount options */
99634bf3	349	erofs_default_options(sbi);
ba2b77a8	350
99634bf3	351	err = erofs_parse_options(sb, data);
8d8a09b0	352	if (err)
8f7acdae	353	return err;
ba2b77a8	354
516c115c GX	355	if (test_opt(sbi, POSIX_ACL))
	356	sb->s_flags \|= SB_POSIXACL;
	357	else
	358	sb->s_flags &= ~SB_POSIXACL;
	359
e7e9a307 GX	360	#ifdef CONFIG_EROFS_FS_ZIP
	361	INIT_RADIX_TREE(&sbi->workstn_tree, GFP_ATOMIC);
	362	#endif
	363
ba2b77a8 GX	364	/* get the root inode */
ba2b77a8 GX	365	inode = erofs_iget(sb, ROOT_NID(sbi), true);
8f7acdae GX	366	if (IS_ERR(inode))
8f7acdae GX	367	return PTR_ERR(inode);
ba2b77a8	368
8d8a09b0	369	if (!S_ISDIR(inode->i_mode)) {
ba2b77a8	370	errln("rootino(nid %llu) is not a directory(i_mode %o)",
447a3621	371	ROOT_NID(sbi), inode->i_mode);
94832d93	372	iput(inode);
8f7acdae	373	return -EINVAL;
ba2b77a8 GX	374	}
	375
	376	sb->s_root = d_make_root(inode);
8d8a09b0	377	if (!sb->s_root)
8f7acdae	378	return -ENOMEM;
ba2b77a8	379
22fe04a7	380	erofs_shrinker_register(sb);
8f7acdae GX	381	/* sb->s_umount is already locked, SB_ACTIVE and SB_BORN are not set */
8f7acdae GX	382	err = erofs_init_managed_cache(sb);
8d8a09b0	383	if (err)
8f7acdae	384	return err;
2497ee41	385
ba2b77a8	386	if (!silent)
688a5f2e GX	387	infoln("mounted on %s with opts: %s, root inode @ nid %llu.",
688a5f2e GX	388	sb->s_id, (char *)data, ROOT_NID(sbi));
ba2b77a8	389	return 0;
8f7acdae GX	390	}
	391
	392	static struct dentry erofs_mount(struct file_system_type fs_type, int flags,
	393	const char dev_name, void data)
	394	{
	395	return mount_bdev(fs_type, flags, dev_name, data, erofs_fill_super);
ba2b77a8 GX	396	}
	397
	398	/*
	399	* could be triggered after deactivate_locked_super()
	400	* is called, thus including umount and failed to initialize.
	401	*/
8f7acdae	402	static void erofs_kill_sb(struct super_block *sb)
ba2b77a8	403	{
8f7acdae GX	404	struct erofs_sb_info *sbi;
	405
	406	WARN_ON(sb->s_magic != EROFS_SUPER_MAGIC);
	407	infoln("unmounting for %s", sb->s_id);
ba2b77a8	408
8f7acdae GX	409	kill_block_super(sb);
	410
	411	sbi = EROFS_SB(sb);
e2ff9f15	412	if (!sbi)
ba2b77a8	413	return;
8f7acdae GX	414	kfree(sbi);
	415	sb->s_fs_info = NULL;
	416	}
ba2b77a8	417
8f7acdae GX	418	/* called when ->s_root is non-NULL */
	419	static void erofs_put_super(struct super_block *sb)
	420	{
	421	struct erofs_sb_info *const sbi = EROFS_SB(sb);
ba2b77a8	422
8f7acdae	423	DBG_BUGON(!sbi);
ba2b77a8	424
22fe04a7	425	erofs_shrinker_unregister(sb);
4279f3f9	426	#ifdef CONFIG_EROFS_FS_ZIP
105d4ad8	427	iput(sbi->managed_cache);
8f7acdae	428	sbi->managed_cache = NULL;
105d4ad8	429	#endif
ba2b77a8 GX	430	}
ba2b77a8 GX	431
ba2b77a8 GX	432	static struct file_system_type erofs_fs_type = {
	433	.owner = THIS_MODULE,
	434	.name = "erofs",
	435	.mount = erofs_mount,
8f7acdae	436	.kill_sb = erofs_kill_sb,
ba2b77a8 GX	437	.fs_flags = FS_REQUIRES_DEV,
	438	};
	439	MODULE_ALIAS_FS("erofs");
	440
	441	static int __init erofs_module_init(void)
	442	{
	443	int err;
	444
	445	erofs_check_ondisk_layout_definitions();
	446	infoln("initializing erofs " EROFS_VERSION);
	447
1c2dfbf9	448	erofs_inode_cachep = kmem_cache_create("erofs_inode",
a5876e24	449	sizeof(struct erofs_inode), 0,
1c2dfbf9	450	SLAB_RECLAIM_ACCOUNT,
99634bf3	451	erofs_inode_init_once);
1c2dfbf9 GX	452	if (!erofs_inode_cachep) {
1c2dfbf9 GX	453	err = -ENOMEM;
ba2b77a8	454	goto icache_err;
1c2dfbf9	455	}
ba2b77a8	456
22fe04a7	457	err = erofs_init_shrinker();
a1581312 GX	458	if (err)
	459	goto shrinker_err;
	460
3883a79a GX	461	err = z_erofs_init_zip_subsystem();
	462	if (err)
	463	goto zip_err;
3883a79a	464
ba2b77a8 GX	465	err = register_filesystem(&erofs_fs_type);
	466	if (err)
	467	goto fs_err;
	468
	469	infoln("successfully to initialize erofs");
	470	return 0;
	471
	472	fs_err:
3883a79a GX	473	z_erofs_exit_zip_subsystem();
3883a79a GX	474	zip_err:
22fe04a7	475	erofs_exit_shrinker();
a1581312	476	shrinker_err:
1c2dfbf9	477	kmem_cache_destroy(erofs_inode_cachep);
ba2b77a8 GX	478	icache_err:
	479	return err;
	480	}
	481
	482	static void __exit erofs_module_exit(void)
	483	{
	484	unregister_filesystem(&erofs_fs_type);
3883a79a	485	z_erofs_exit_zip_subsystem();
22fe04a7	486	erofs_exit_shrinker();
1c2dfbf9 GX	487
	488	/* Ensure all RCU free inodes are safe before cache is destroyed. */
	489	rcu_barrier();
	490	kmem_cache_destroy(erofs_inode_cachep);
ba2b77a8 GX	491	infoln("successfully finalize erofs");
	492	}
	493
	494	/* get filesystem statistics */
	495	static int erofs_statfs(struct dentry dentry, struct kstatfs buf)
	496	{
	497	struct super_block *sb = dentry->d_sb;
	498	struct erofs_sb_info *sbi = EROFS_SB(sb);
	499	u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
	500
	501	buf->f_type = sb->s_magic;
	502	buf->f_bsize = EROFS_BLKSIZ;
	503	buf->f_blocks = sbi->blocks;
	504	buf->f_bfree = buf->f_bavail = 0;
	505
	506	buf->f_files = ULLONG_MAX;
	507	buf->f_ffree = ULLONG_MAX - sbi->inos;
	508
	509	buf->f_namelen = EROFS_NAME_LEN;
	510
	511	buf->f_fsid.val[0] = (u32)id;
	512	buf->f_fsid.val[1] = (u32)(id >> 32);
	513	return 0;
	514	}
	515
	516	static int erofs_show_options(struct seq_file seq, struct dentry root)
	517	{
b17500a0 GX	518	struct erofs_sb_info *sbi __maybe_unused = EROFS_SB(root->d_sb);
	519
	520	#ifdef CONFIG_EROFS_FS_XATTR
	521	if (test_opt(sbi, XATTR_USER))
	522	seq_puts(seq, ",user_xattr");
	523	else
	524	seq_puts(seq, ",nouser_xattr");
	525	#endif
	526	#ifdef CONFIG_EROFS_FS_POSIX_ACL
	527	if (test_opt(sbi, POSIX_ACL))
	528	seq_puts(seq, ",acl");
	529	else
	530	seq_puts(seq, ",noacl");
9c07b3b3	531	#endif
4279f3f9 GX	532	#ifdef CONFIG_EROFS_FS_ZIP
	533	if (sbi->cache_strategy == EROFS_ZIP_CACHE_DISABLED) {
	534	seq_puts(seq, ",cache_strategy=disabled");
	535	} else if (sbi->cache_strategy == EROFS_ZIP_CACHE_READAHEAD) {
	536	seq_puts(seq, ",cache_strategy=readahead");
	537	} else if (sbi->cache_strategy == EROFS_ZIP_CACHE_READAROUND) {
	538	seq_puts(seq, ",cache_strategy=readaround");
	539	} else {
	540	seq_puts(seq, ",cache_strategy=(unknown)");
	541	DBG_BUGON(1);
	542	}
	543	#endif
ba2b77a8 GX	544	return 0;
	545	}
	546
	547	static int erofs_remount(struct super_block sb, int flags, char *data)
	548	{
d41076ea CX	549	struct erofs_sb_info *sbi = EROFS_SB(sb);
d41076ea CX	550	unsigned int org_mnt_opt = sbi->mount_opt;
d41076ea CX	551	int err;
d41076ea CX	552
8b987bca	553	DBG_BUGON(!sb_rdonly(sb));
99634bf3	554	err = erofs_parse_options(sb, data);
d41076ea CX	555	if (err)
d41076ea CX	556	goto out;
ba2b77a8	557
516c115c GX	558	if (test_opt(sbi, POSIX_ACL))
	559	sb->s_flags \|= SB_POSIXACL;
	560	else
	561	sb->s_flags &= ~SB_POSIXACL;
	562
5f0abea6	563	*flags \|= SB_RDONLY;
ba2b77a8	564	return 0;
d41076ea	565	out:
d41076ea	566	sbi->mount_opt = org_mnt_opt;
d41076ea	567	return err;
ba2b77a8 GX	568	}
	569
	570	const struct super_operations erofs_sops = {
	571	.put_super = erofs_put_super,
99634bf3 GX	572	.alloc_inode = erofs_alloc_inode,
99634bf3 GX	573	.free_inode = erofs_free_inode,
ba2b77a8 GX	574	.statfs = erofs_statfs,
	575	.show_options = erofs_show_options,
	576	.remount_fs = erofs_remount,
	577	};
	578
	579	module_init(erofs_module_init);
	580	module_exit(erofs_module_exit);
	581
	582	MODULE_DESCRIPTION("Enhanced ROM File System");
bc33d9f3	583	MODULE_AUTHOR("Gao Xiang, Chao Yu, Miao Xie, CONSUMER BG, HUAWEI Inc.");
ba2b77a8 GX	584	MODULE_LICENSE("GPL");
ba2b77a8 GX	585