fs/bcachefs/opts.c - pub/scm/linux/kernel/git/joro/iommu - Git at Google

 // SPDX-License-Identifier: GPL-2.0

 #include <linux/kernel.h>

 #include "bcachefs.h"
 #include "compress.h"
 #include "disk_groups.h"
 #include "error.h"
 #include "opts.h"
 #include "recovery_passes.h"
 #include "super-io.h"
 #include "util.h"

 #define x(t, n, ...) [n] = #t,

 const char * const bch2_error_actions[] = {
 	BCH_ERROR_ACTIONS()
 	NULL
 };

 const char * const bch2_fsck_fix_opts[] = {
 	BCH_FIX_ERRORS_OPTS()
 	NULL
 };

 const char * const bch2_version_upgrade_opts[] = {
 	BCH_VERSION_UPGRADE_OPTS()
 	NULL
 };

 const char * const bch2_sb_features[] = {
 	BCH_SB_FEATURES()
 	NULL
 };

 const char * const bch2_sb_compat[] = {
 	BCH_SB_COMPAT()
 	NULL
 };

 const char * const __bch2_btree_ids[] = {
 	BCH_BTREE_IDS()
 	NULL
 };

 const char * const bch2_csum_types[] = {
 	BCH_CSUM_TYPES()
 	NULL
 };

 const char * const bch2_csum_opts[] = {
 	BCH_CSUM_OPTS()
 	NULL
 };

 const char * const __bch2_compression_types[] = {
 	BCH_COMPRESSION_TYPES()
 	NULL
 };

 const char * const bch2_compression_opts[] = {
 	BCH_COMPRESSION_OPTS()
 	NULL
 };

 const char * const bch2_str_hash_types[] = {
 	BCH_STR_HASH_TYPES()
 	NULL
 };

 const char * const bch2_str_hash_opts[] = {
 	BCH_STR_HASH_OPTS()
 	NULL
 };

 const char * const __bch2_data_types[] = {
 	BCH_DATA_TYPES()
 	NULL
 };

 const char * const bch2_member_states[] = {
 	BCH_MEMBER_STATES()
 	NULL
 };

 const char * const bch2_jset_entry_types[] = {
 	BCH_JSET_ENTRY_TYPES()
 	NULL
 };

 const char * const bch2_fs_usage_types[] = {
 	BCH_FS_USAGE_TYPES()
 	NULL
 };

 #undef x

 static int bch2_opt_fix_errors_parse(struct bch_fs *c, const char *val, u64 *res,
 				     struct printbuf *err)
 {
 	if (!val) {
 		*res = FSCK_FIX_yes;
 	} else {
 		int ret = match_string(bch2_fsck_fix_opts, -1, val);

 		if (ret < 0 && err)
 			prt_str(err, "fix_errors: invalid selection");
 		if (ret < 0)
 			return ret;
 		*res = ret;
 	}

 	return 0;
 }

 static void bch2_opt_fix_errors_to_text(struct printbuf *out,
 					struct bch_fs *c,
 					struct bch_sb *sb,
 					u64 v)
 {
 	prt_str(out, bch2_fsck_fix_opts[v]);
 }

 #define bch2_opt_fix_errors (struct bch_opt_fn) {	\
 	.parse = bch2_opt_fix_errors_parse,		\
 	.to_text = bch2_opt_fix_errors_to_text,		\
 }

 const char * const bch2_d_types[BCH_DT_MAX] = {
 	[DT_UNKNOWN]	= "unknown",
 	[DT_FIFO]	= "fifo",
 	[DT_CHR]	= "chr",
 	[DT_DIR]	= "dir",
 	[DT_BLK]	= "blk",
 	[DT_REG]	= "reg",
 	[DT_LNK]	= "lnk",
 	[DT_SOCK]	= "sock",
 	[DT_WHT]	= "whiteout",
 	[DT_SUBVOL]	= "subvol",
 };

 u64 BCH2_NO_SB_OPT(const struct bch_sb *sb)
 {
 	BUG();
 }

 void SET_BCH2_NO_SB_OPT(struct bch_sb *sb, u64 v)
 {
 	BUG();
 }

 void bch2_opts_apply(struct bch_opts *dst, struct bch_opts src)
 {
 #define x(_name, ...)						\
 	if (opt_defined(src, _name))					\
 		opt_set(*dst, _name, src._name);

 	BCH_OPTS()
 #undef x
 }

 bool bch2_opt_defined_by_id(const struct bch_opts *opts, enum bch_opt_id id)
 {
 	switch (id) {
 #define x(_name, ...)						\
 	case Opt_##_name:						\
 		return opt_defined(*opts, _name);
 	BCH_OPTS()
 #undef x
 	default:
 		BUG();
 	}
 }

 u64 bch2_opt_get_by_id(const struct bch_opts *opts, enum bch_opt_id id)
 {
 	switch (id) {
 #define x(_name, ...)						\
 	case Opt_##_name:						\
 		return opts->_name;
 	BCH_OPTS()
 #undef x
 	default:
 		BUG();
 	}
 }

 void bch2_opt_set_by_id(struct bch_opts *opts, enum bch_opt_id id, u64 v)
 {
 	switch (id) {
 #define x(_name, ...)						\
 	case Opt_##_name:						\
 		opt_set(*opts, _name, v);				\
 		break;
 	BCH_OPTS()
 #undef x
 	default:
 		BUG();
 	}
 }

 const struct bch_option bch2_opt_table[] = {
 #define OPT_BOOL()		.type = BCH_OPT_BOOL, .min = 0, .max = 2
 #define OPT_UINT(_min, _max)	.type = BCH_OPT_UINT,			\
 				.min = _min, .max = _max
 #define OPT_STR(_choices)	.type = BCH_OPT_STR,			\
 				.min = 0, .max = ARRAY_SIZE(_choices),	\
 				.choices = _choices
 #define OPT_STR_NOLIMIT(_choices)	.type = BCH_OPT_STR,		\
 				.min = 0, .max = U64_MAX,		\
 				.choices = _choices
 #define OPT_FN(_fn)		.type = BCH_OPT_FN, .fn	= _fn

 #define x(_name, _bits, _flags, _type, _sb_opt, _default, _hint, _help)	\
 	[Opt_##_name] = {						\
 		.attr	= {						\
 			.name	= #_name,				\
 			.mode = (_flags) & OPT_RUNTIME ? 0644 : 0444,	\
 		},							\
 		.flags	= _flags,					\
 		.hint	= _hint,					\
 		.help	= _help,					\
 		.get_sb = _sb_opt,					\
 		.set_sb	= SET_##_sb_opt,				\
 		_type							\
 	},

 	BCH_OPTS()
 #undef x
 };

 int bch2_opt_lookup(const char *name)
 {
 	const struct bch_option *i;

 	for (i = bch2_opt_table;
 	     i < bch2_opt_table + ARRAY_SIZE(bch2_opt_table);
 	     i++)
 		if (!strcmp(name, i->attr.name))
 			return i - bch2_opt_table;

 	return -1;
 }

 struct synonym {
 	const char	*s1, *s2;
 };

 static const struct synonym bch_opt_synonyms[] = {
 	{ "quota",	"usrquota" },
 };

 static int bch2_mount_opt_lookup(const char *name)
 {
 	const struct synonym *i;

 	for (i = bch_opt_synonyms;
 	     i < bch_opt_synonyms + ARRAY_SIZE(bch_opt_synonyms);
 	     i++)
 		if (!strcmp(name, i->s1))
 			name = i->s2;

 	return bch2_opt_lookup(name);
 }

 int bch2_opt_validate(const struct bch_option *opt, u64 v, struct printbuf *err)
 {
 	if (v < opt->min) {
 		if (err)
 			prt_printf(err, "%s: too small (min %llu)",
 			       opt->attr.name, opt->min);
 		return -BCH_ERR_ERANGE_option_too_small;
 	}

 	if (opt->max && v >= opt->max) {
 		if (err)
 			prt_printf(err, "%s: too big (max %llu)",
 			       opt->attr.name, opt->max);
 		return -BCH_ERR_ERANGE_option_too_big;
 	}

 	if ((opt->flags & OPT_SB_FIELD_SECTORS) && (v & 511)) {
 		if (err)
 			prt_printf(err, "%s: not a multiple of 512",
 			       opt->attr.name);
 		return -BCH_ERR_opt_parse_error;
 	}

 	if ((opt->flags & OPT_MUST_BE_POW_2) && !is_power_of_2(v)) {
 		if (err)
 			prt_printf(err, "%s: must be a power of two",
 			       opt->attr.name);
 		return -BCH_ERR_opt_parse_error;
 	}

 	if (opt->fn.validate)
 		return opt->fn.validate(v, err);

 	return 0;
 }

 int bch2_opt_parse(struct bch_fs *c,
 		   const struct bch_option *opt,
 		   const char *val, u64 *res,
 		   struct printbuf *err)
 {
 	ssize_t ret;

 	switch (opt->type) {
 	case BCH_OPT_BOOL:
 		if (val) {
 			ret = kstrtou64(val, 10, res);
 		} else {
 			ret = 0;
 			*res = 1;
 		}

 		if (ret < 0 || (*res != 0 && *res != 1)) {
 			if (err)
 				prt_printf(err, "%s: must be bool", opt->attr.name);
 			return ret < 0 ? ret : -BCH_ERR_option_not_bool;
 		}
 		break;
 	case BCH_OPT_UINT:
 		if (!val) {
 			prt_printf(err, "%s: required value",
 				   opt->attr.name);
 			return -EINVAL;
 		}

 		ret = opt->flags & OPT_HUMAN_READABLE
 			? bch2_strtou64_h(val, res)
 			: kstrtou64(val, 10, res);
 		if (ret < 0) {
 			if (err)
 				prt_printf(err, "%s: must be a number",
 					   opt->attr.name);
 			return ret;
 		}
 		break;
 	case BCH_OPT_STR:
 		if (!val) {
 			prt_printf(err, "%s: required value",
 				   opt->attr.name);
 			return -EINVAL;
 		}

 		ret = match_string(opt->choices, -1, val);
 		if (ret < 0) {
 			if (err)
 				prt_printf(err, "%s: invalid selection",
 					   opt->attr.name);
 			return ret;
 		}

 		*res = ret;
 		break;
 	case BCH_OPT_FN:
 		ret = opt->fn.parse(c, val, res, err);
 		if (ret < 0) {
 			if (err)
 				prt_printf(err, "%s: parse error",
 					   opt->attr.name);
 			return ret;
 		}
 	}

 	return bch2_opt_validate(opt, *res, err);
 }

 void bch2_opt_to_text(struct printbuf *out,
 		      struct bch_fs *c, struct bch_sb *sb,
 		      const struct bch_option *opt, u64 v,
 		      unsigned flags)
 {
 	if (flags & OPT_SHOW_MOUNT_STYLE) {
 		if (opt->type == BCH_OPT_BOOL) {
 			prt_printf(out, "%s%s",
 			       v ? "" : "no",
 			       opt->attr.name);
 			return;
 		}

 		prt_printf(out, "%s=", opt->attr.name);
 	}

 	switch (opt->type) {
 	case BCH_OPT_BOOL:
 	case BCH_OPT_UINT:
 		if (opt->flags & OPT_HUMAN_READABLE)
 			prt_human_readable_u64(out, v);
 		else
 			prt_printf(out, "%lli", v);
 		break;
 	case BCH_OPT_STR:
 		if (flags & OPT_SHOW_FULL_LIST)
 			prt_string_option(out, opt->choices, v);
 		else
 			prt_str(out, opt->choices[v]);
 		break;
 	case BCH_OPT_FN:
 		opt->fn.to_text(out, c, sb, v);
 		break;
 	default:
 		BUG();
 	}
 }

 int bch2_opt_check_may_set(struct bch_fs *c, int id, u64 v)
 {
 	int ret = 0;

 	switch (id) {
 	case Opt_compression:
 	case Opt_background_compression:
 		ret = bch2_check_set_has_compressed_data(c, v);
 		break;
 	case Opt_erasure_code:
 		if (v)
 			bch2_check_set_feature(c, BCH_FEATURE_ec);
 		break;
 	}

 	return ret;
 }

 int bch2_opts_check_may_set(struct bch_fs *c)
 {
 	unsigned i;
 	int ret;

 	for (i = 0; i < bch2_opts_nr; i++) {
 		ret = bch2_opt_check_may_set(c, i,
 				bch2_opt_get_by_id(&c->opts, i));
 		if (ret)
 			return ret;
 	}

 	return 0;
 }

 int bch2_parse_mount_opts(struct bch_fs *c, struct bch_opts *opts,
 			  char *options)
 {
 	char *copied_opts, *copied_opts_start;
 	char *opt, *name, *val;
 	int ret, id;
 	struct printbuf err = PRINTBUF;
 	u64 v;

 	if (!options)
 		return 0;

 	/*
 	 * sys_fsconfig() is now occasionally providing us with option lists
 	 * starting with a comma - weird.
 	 */
 	if (*options == ',')
 		options++;

 	copied_opts = kstrdup(options, GFP_KERNEL);
 	if (!copied_opts)
 		return -ENOMEM;
 	copied_opts_start = copied_opts;

 	while ((opt = strsep(&copied_opts, ",")) != NULL) {
 		name	= strsep(&opt, "=");
 		val	= opt;

 		id = bch2_mount_opt_lookup(name);

 		/* Check for the form "noopt", negation of a boolean opt: */
 		if (id < 0 &&
 		    !val &&
 		    !strncmp("no", name, 2)) {
 			id = bch2_mount_opt_lookup(name + 2);
 			val = "0";
 		}

 		/* Unknown options are ignored: */
 		if (id < 0)
 			continue;

 		if (!(bch2_opt_table[id].flags & OPT_MOUNT))
 			goto bad_opt;

 		if (id == Opt_acl &&
 		    !IS_ENABLED(CONFIG_BCACHEFS_POSIX_ACL))
 			goto bad_opt;

 		if ((id == Opt_usrquota ||
 		     id == Opt_grpquota) &&
 		    !IS_ENABLED(CONFIG_BCACHEFS_QUOTA))
 			goto bad_opt;

 		ret = bch2_opt_parse(c, &bch2_opt_table[id], val, &v, &err);
 		if (ret < 0)
 			goto bad_val;

 		bch2_opt_set_by_id(opts, id, v);
 	}

 	ret = 0;
 	goto out;

 bad_opt:
 	pr_err("Bad mount option %s", name);
 	ret = -BCH_ERR_option_name;
 	goto out;
 bad_val:
 	pr_err("Invalid mount option %s", err.buf);
 	ret = -BCH_ERR_option_value;
 	goto out;
 out:
 	kfree(copied_opts_start);
 	printbuf_exit(&err);
 	return ret;
 }

 u64 bch2_opt_from_sb(struct bch_sb *sb, enum bch_opt_id id)
 {
 	const struct bch_option *opt = bch2_opt_table + id;
 	u64 v;

 	v = opt->get_sb(sb);

 	if (opt->flags & OPT_SB_FIELD_ILOG2)
 		v = 1ULL << v;

 	if (opt->flags & OPT_SB_FIELD_SECTORS)
 		v <<= 9;

 	return v;
 }

 /*
  * Initial options from superblock - here we don't want any options undefined,
  * any options the superblock doesn't specify are set to 0:
  */
 int bch2_opts_from_sb(struct bch_opts *opts, struct bch_sb *sb)
 {
 	unsigned id;

 	for (id = 0; id < bch2_opts_nr; id++) {
 		const struct bch_option *opt = bch2_opt_table + id;

 		if (opt->get_sb == BCH2_NO_SB_OPT)
 			continue;

 		bch2_opt_set_by_id(opts, id, bch2_opt_from_sb(sb, id));
 	}

 	return 0;
 }

 void __bch2_opt_set_sb(struct bch_sb *sb, const struct bch_option *opt, u64 v)
 {
 	if (opt->set_sb == SET_BCH2_NO_SB_OPT)
 		return;

 	if (opt->flags & OPT_SB_FIELD_SECTORS)
 		v >>= 9;

 	if (opt->flags & OPT_SB_FIELD_ILOG2)
 		v = ilog2(v);

 	opt->set_sb(sb, v);
 }

 void bch2_opt_set_sb(struct bch_fs *c, const struct bch_option *opt, u64 v)
 {
 	if (opt->set_sb == SET_BCH2_NO_SB_OPT)
 		return;

 	mutex_lock(&c->sb_lock);
 	__bch2_opt_set_sb(c->disk_sb.sb, opt, v);
 	bch2_write_super(c);
 	mutex_unlock(&c->sb_lock);
 }

 /* io opts: */

 struct bch_io_opts bch2_opts_to_inode_opts(struct bch_opts src)
 {
 	return (struct bch_io_opts) {
 #define x(_name, _bits)	._name = src._name,
 	BCH_INODE_OPTS()
 #undef x
 	};
 }

 bool bch2_opt_is_inode_opt(enum bch_opt_id id)
 {
 	static const enum bch_opt_id inode_opt_list[] = {
 #define x(_name, _bits)	Opt_##_name,
 	BCH_INODE_OPTS()
 #undef x
 	};
 	unsigned i;

 	for (i = 0; i < ARRAY_SIZE(inode_opt_list); i++)
 		if (inode_opt_list[i] == id)
 			return true;

 	return false;
 }
	// SPDX-License-Identifier: GPL-2.0

	#include <linux/kernel.h>

	#include "bcachefs.h"
	#include "compress.h"
	#include "disk_groups.h"
	#include "error.h"
	#include "opts.h"
	#include "recovery_passes.h"
	#include "super-io.h"
	#include "util.h"

	#define x(t, n, ...) [n] = #t,

	const char * const bch2_error_actions[] = {
	BCH_ERROR_ACTIONS()
	NULL
	};

	const char * const bch2_fsck_fix_opts[] = {
	BCH_FIX_ERRORS_OPTS()
	NULL
	};

	const char * const bch2_version_upgrade_opts[] = {
	BCH_VERSION_UPGRADE_OPTS()
	NULL
	};

	const char * const bch2_sb_features[] = {
	BCH_SB_FEATURES()
	NULL
	};

	const char * const bch2_sb_compat[] = {
	BCH_SB_COMPAT()
	NULL
	};

	const char * const __bch2_btree_ids[] = {
	BCH_BTREE_IDS()
	NULL
	};

	const char * const bch2_csum_types[] = {
	BCH_CSUM_TYPES()
	NULL
	};

	const char * const bch2_csum_opts[] = {
	BCH_CSUM_OPTS()
	NULL
	};

	const char * const __bch2_compression_types[] = {
	BCH_COMPRESSION_TYPES()
	NULL
	};

	const char * const bch2_compression_opts[] = {
	BCH_COMPRESSION_OPTS()
	NULL
	};

	const char * const bch2_str_hash_types[] = {
	BCH_STR_HASH_TYPES()
	NULL
	};

	const char * const bch2_str_hash_opts[] = {
	BCH_STR_HASH_OPTS()
	NULL
	};

	const char * const __bch2_data_types[] = {
	BCH_DATA_TYPES()
	NULL
	};

	const char * const bch2_member_states[] = {
	BCH_MEMBER_STATES()
	NULL
	};

	const char * const bch2_jset_entry_types[] = {
	BCH_JSET_ENTRY_TYPES()
	NULL
	};

	const char * const bch2_fs_usage_types[] = {
	BCH_FS_USAGE_TYPES()
	NULL
	};

	#undef x

	static int bch2_opt_fix_errors_parse(struct bch_fs c, const char val, u64 *res,
	struct printbuf *err)
	{
	if (!val) {
	*res = FSCK_FIX_yes;
	} else {
	int ret = match_string(bch2_fsck_fix_opts, -1, val);

	if (ret < 0 && err)
	prt_str(err, "fix_errors: invalid selection");
	if (ret < 0)
	return ret;
	*res = ret;
	}

	return 0;
	}

	static void bch2_opt_fix_errors_to_text(struct printbuf *out,
	struct bch_fs *c,
	struct bch_sb *sb,
	u64 v)
	{
	prt_str(out, bch2_fsck_fix_opts[v]);
	}

	#define bch2_opt_fix_errors (struct bch_opt_fn) { \
	.parse = bch2_opt_fix_errors_parse, \
	.to_text = bch2_opt_fix_errors_to_text, \
	}

	const char * const bch2_d_types[BCH_DT_MAX] = {
	[DT_UNKNOWN] = "unknown",
	[DT_FIFO] = "fifo",
	[DT_CHR] = "chr",
	[DT_DIR] = "dir",
	[DT_BLK] = "blk",
	[DT_REG] = "reg",
	[DT_LNK] = "lnk",
	[DT_SOCK] = "sock",
	[DT_WHT] = "whiteout",
	[DT_SUBVOL] = "subvol",
	};

	u64 BCH2_NO_SB_OPT(const struct bch_sb *sb)
	{
	BUG();
	}

	void SET_BCH2_NO_SB_OPT(struct bch_sb *sb, u64 v)
	{
	BUG();
	}

	void bch2_opts_apply(struct bch_opts *dst, struct bch_opts src)
	{
	#define x(_name, ...) \
	if (opt_defined(src, _name)) \
	opt_set(*dst, _name, src._name);

	BCH_OPTS()
	#undef x
	}

	bool bch2_opt_defined_by_id(const struct bch_opts *opts, enum bch_opt_id id)
	{
	switch (id) {
	#define x(_name, ...) \
	case Opt_##_name: \
	return opt_defined(*opts, _name);
	BCH_OPTS()
	#undef x
	default:
	BUG();
	}
	}

	u64 bch2_opt_get_by_id(const struct bch_opts *opts, enum bch_opt_id id)
	{
	switch (id) {
	#define x(_name, ...) \
	case Opt_##_name: \
	return opts->_name;
	BCH_OPTS()
	#undef x
	default:
	BUG();
	}
	}

	void bch2_opt_set_by_id(struct bch_opts *opts, enum bch_opt_id id, u64 v)
	{
	switch (id) {
	#define x(_name, ...) \
	case Opt_##_name: \
	opt_set(*opts, _name, v); \
	break;
	BCH_OPTS()
	#undef x
	default:
	BUG();
	}
	}

	const struct bch_option bch2_opt_table[] = {
	#define OPT_BOOL() .type = BCH_OPT_BOOL, .min = 0, .max = 2
	#define OPT_UINT(_min, _max) .type = BCH_OPT_UINT, \
	.min = _min, .max = _max
	#define OPT_STR(_choices) .type = BCH_OPT_STR, \
	.min = 0, .max = ARRAY_SIZE(_choices), \
	.choices = _choices
	#define OPT_STR_NOLIMIT(_choices) .type = BCH_OPT_STR, \
	.min = 0, .max = U64_MAX, \
	.choices = _choices
	#define OPT_FN(_fn) .type = BCH_OPT_FN, .fn = _fn

	#define x(_name, _bits, _flags, _type, _sb_opt, _default, _hint, _help) \
	[Opt_##_name] = { \
	.attr = { \
	.name = #_name, \
	.mode = (_flags) & OPT_RUNTIME ? 0644 : 0444, \
	}, \
	.flags = _flags, \
	.hint = _hint, \
	.help = _help, \
	.get_sb = _sb_opt, \
	.set_sb = SET_##_sb_opt, \
	_type \
	},

	BCH_OPTS()
	#undef x
	};

	int bch2_opt_lookup(const char *name)
	{
	const struct bch_option *i;

	for (i = bch2_opt_table;
	i < bch2_opt_table + ARRAY_SIZE(bch2_opt_table);
	i++)
	if (!strcmp(name, i->attr.name))
	return i - bch2_opt_table;

	return -1;
	}

	struct synonym {
	const char s1, s2;
	};

	static const struct synonym bch_opt_synonyms[] = {
	{ "quota", "usrquota" },
	};

	static int bch2_mount_opt_lookup(const char *name)
	{
	const struct synonym *i;

	for (i = bch_opt_synonyms;
	i < bch_opt_synonyms + ARRAY_SIZE(bch_opt_synonyms);
	i++)
	if (!strcmp(name, i->s1))
	name = i->s2;

	return bch2_opt_lookup(name);
	}

	int bch2_opt_validate(const struct bch_option opt, u64 v, struct printbuf err)
	{
	if (v < opt->min) {
	if (err)
	prt_printf(err, "%s: too small (min %llu)",
	opt->attr.name, opt->min);
	return -BCH_ERR_ERANGE_option_too_small;
	}

	if (opt->max && v >= opt->max) {
	if (err)
	prt_printf(err, "%s: too big (max %llu)",
	opt->attr.name, opt->max);
	return -BCH_ERR_ERANGE_option_too_big;
	}

	if ((opt->flags & OPT_SB_FIELD_SECTORS) && (v & 511)) {
	if (err)
	prt_printf(err, "%s: not a multiple of 512",
	opt->attr.name);
	return -BCH_ERR_opt_parse_error;
	}

	if ((opt->flags & OPT_MUST_BE_POW_2) && !is_power_of_2(v)) {
	if (err)
	prt_printf(err, "%s: must be a power of two",
	opt->attr.name);
	return -BCH_ERR_opt_parse_error;
	}

	if (opt->fn.validate)
	return opt->fn.validate(v, err);

	return 0;
	}

	int bch2_opt_parse(struct bch_fs *c,
	const struct bch_option *opt,
	const char val, u64 res,
	struct printbuf *err)
	{
	ssize_t ret;

	switch (opt->type) {
	case BCH_OPT_BOOL:
	if (val) {
	ret = kstrtou64(val, 10, res);
	} else {
	ret = 0;
	*res = 1;
	}

	if (ret < 0 \|\| (res != 0 && res != 1)) {
	if (err)
	prt_printf(err, "%s: must be bool", opt->attr.name);
	return ret < 0 ? ret : -BCH_ERR_option_not_bool;
	}
	break;
	case BCH_OPT_UINT:
	if (!val) {
	prt_printf(err, "%s: required value",
	opt->attr.name);
	return -EINVAL;
	}

	ret = opt->flags & OPT_HUMAN_READABLE
	? bch2_strtou64_h(val, res)
	: kstrtou64(val, 10, res);
	if (ret < 0) {
	if (err)
	prt_printf(err, "%s: must be a number",
	opt->attr.name);
	return ret;
	}
	break;
	case BCH_OPT_STR:
	if (!val) {
	prt_printf(err, "%s: required value",
	opt->attr.name);
	return -EINVAL;
	}

	ret = match_string(opt->choices, -1, val);
	if (ret < 0) {
	if (err)
	prt_printf(err, "%s: invalid selection",
	opt->attr.name);
	return ret;
	}

	*res = ret;
	break;
	case BCH_OPT_FN:
	ret = opt->fn.parse(c, val, res, err);
	if (ret < 0) {
	if (err)
	prt_printf(err, "%s: parse error",
	opt->attr.name);
	return ret;
	}
	}

	return bch2_opt_validate(opt, *res, err);
	}

	void bch2_opt_to_text(struct printbuf *out,
	struct bch_fs c, struct bch_sb sb,
	const struct bch_option *opt, u64 v,
	unsigned flags)
	{
	if (flags & OPT_SHOW_MOUNT_STYLE) {
	if (opt->type == BCH_OPT_BOOL) {
	prt_printf(out, "%s%s",
	v ? "" : "no",
	opt->attr.name);
	return;
	}

	prt_printf(out, "%s=", opt->attr.name);
	}

	switch (opt->type) {
	case BCH_OPT_BOOL:
	case BCH_OPT_UINT:
	if (opt->flags & OPT_HUMAN_READABLE)
	prt_human_readable_u64(out, v);
	else
	prt_printf(out, "%lli", v);
	break;
	case BCH_OPT_STR:
	if (flags & OPT_SHOW_FULL_LIST)
	prt_string_option(out, opt->choices, v);
	else
	prt_str(out, opt->choices[v]);
	break;
	case BCH_OPT_FN:
	opt->fn.to_text(out, c, sb, v);
	break;
	default:
	BUG();
	}
	}

	int bch2_opt_check_may_set(struct bch_fs *c, int id, u64 v)
	{
	int ret = 0;

	switch (id) {
	case Opt_compression:
	case Opt_background_compression:
	ret = bch2_check_set_has_compressed_data(c, v);
	break;
	case Opt_erasure_code:
	if (v)
	bch2_check_set_feature(c, BCH_FEATURE_ec);
	break;
	}

	return ret;
	}

	int bch2_opts_check_may_set(struct bch_fs *c)
	{
	unsigned i;
	int ret;

	for (i = 0; i < bch2_opts_nr; i++) {
	ret = bch2_opt_check_may_set(c, i,
	bch2_opt_get_by_id(&c->opts, i));
	if (ret)
	return ret;
	}

	return 0;
	}

	int bch2_parse_mount_opts(struct bch_fs c, struct bch_opts opts,
	char *options)
	{
	char copied_opts, copied_opts_start;
	char opt, name, *val;
	int ret, id;
	struct printbuf err = PRINTBUF;
	u64 v;

	if (!options)
	return 0;

	/*
	* sys_fsconfig() is now occasionally providing us with option lists
	* starting with a comma - weird.
	*/
	if (*options == ',')
	options++;

	copied_opts = kstrdup(options, GFP_KERNEL);
	if (!copied_opts)
	return -ENOMEM;
	copied_opts_start = copied_opts;

	while ((opt = strsep(&copied_opts, ",")) != NULL) {
	name = strsep(&opt, "=");
	val = opt;

	id = bch2_mount_opt_lookup(name);

	/* Check for the form "noopt", negation of a boolean opt: */
	if (id < 0 &&
	!val &&
	!strncmp("no", name, 2)) {
	id = bch2_mount_opt_lookup(name + 2);
	val = "0";
	}

	/* Unknown options are ignored: */
	if (id < 0)
	continue;

	if (!(bch2_opt_table[id].flags & OPT_MOUNT))
	goto bad_opt;

	if (id == Opt_acl &&
	!IS_ENABLED(CONFIG_BCACHEFS_POSIX_ACL))
	goto bad_opt;

	if ((id == Opt_usrquota \|\|
	id == Opt_grpquota) &&
	!IS_ENABLED(CONFIG_BCACHEFS_QUOTA))
	goto bad_opt;

	ret = bch2_opt_parse(c, &bch2_opt_table[id], val, &v, &err);
	if (ret < 0)
	goto bad_val;

	bch2_opt_set_by_id(opts, id, v);
	}

	ret = 0;
	goto out;

	bad_opt:
	pr_err("Bad mount option %s", name);
	ret = -BCH_ERR_option_name;
	goto out;
	bad_val:
	pr_err("Invalid mount option %s", err.buf);
	ret = -BCH_ERR_option_value;
	goto out;
	out:
	kfree(copied_opts_start);
	printbuf_exit(&err);
	return ret;
	}

	u64 bch2_opt_from_sb(struct bch_sb *sb, enum bch_opt_id id)
	{
	const struct bch_option *opt = bch2_opt_table + id;
	u64 v;

	v = opt->get_sb(sb);

	if (opt->flags & OPT_SB_FIELD_ILOG2)
	v = 1ULL << v;

	if (opt->flags & OPT_SB_FIELD_SECTORS)
	v <<= 9;

	return v;
	}

	/*
	* Initial options from superblock - here we don't want any options undefined,
	* any options the superblock doesn't specify are set to 0:
	*/
	int bch2_opts_from_sb(struct bch_opts opts, struct bch_sb sb)
	{
	unsigned id;

	for (id = 0; id < bch2_opts_nr; id++) {
	const struct bch_option *opt = bch2_opt_table + id;

	if (opt->get_sb == BCH2_NO_SB_OPT)
	continue;

	bch2_opt_set_by_id(opts, id, bch2_opt_from_sb(sb, id));
	}

	return 0;
	}

	void __bch2_opt_set_sb(struct bch_sb sb, const struct bch_option opt, u64 v)
	{
	if (opt->set_sb == SET_BCH2_NO_SB_OPT)
	return;

	if (opt->flags & OPT_SB_FIELD_SECTORS)
	v >>= 9;

	if (opt->flags & OPT_SB_FIELD_ILOG2)
	v = ilog2(v);

	opt->set_sb(sb, v);
	}

	void bch2_opt_set_sb(struct bch_fs c, const struct bch_option opt, u64 v)
	{
	if (opt->set_sb == SET_BCH2_NO_SB_OPT)
	return;

	mutex_lock(&c->sb_lock);
	__bch2_opt_set_sb(c->disk_sb.sb, opt, v);
	bch2_write_super(c);
	mutex_unlock(&c->sb_lock);
	}

	/* io opts: */

	struct bch_io_opts bch2_opts_to_inode_opts(struct bch_opts src)
	{
	return (struct bch_io_opts) {
	#define x(_name, _bits) ._name = src._name,
	BCH_INODE_OPTS()
	#undef x
	};
	}

	bool bch2_opt_is_inode_opt(enum bch_opt_id id)
	{
	static const enum bch_opt_id inode_opt_list[] = {
	#define x(_name, _bits) Opt_##_name,
	BCH_INODE_OPTS()
	#undef x
	};
	unsigned i;

	for (i = 0; i < ARRAY_SIZE(inode_opt_list); i++)
	if (inode_opt_list[i] == id)
	return true;

	return false;
	}