Re: [PATCH] hpfs: convert hpfs to use the new mount api

[Eric Sandeen <sandeen@redhat.com>]

On 9/25/24 8:17 AM, Mikulas Patocka wrote:
> Hi
> 
> Here I'm sending Eric's patch that converts hpfs to use the new mount API.
> 
> Mikulas
> 

Oh, thanks Mikulas.

Cc: Christian who has been collecting a few other mount API conversions in a
git branch for 6.13, I think.

Thanks,
-Eric
 
> 
> From: Eric Sandeen <sandeen@redhat.com>
> 
> Convert the hpfs filesystem to use the new mount API.
> Tested by comparing random mount & remount options before and after
> the change.
> 
> Signed-off-by: Eric Sandeen <sandeen@redhat.com>
> Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
> ---
>  fs/hpfs/super.c | 414 ++++++++++++++++++++++++------------------------
>  1 file changed, 204 insertions(+), 210 deletions(-)
> 
> diff --git a/fs/hpfs/super.c b/fs/hpfs/super.c
> index e73717daa5f9..27567920abe4 100644
> --- a/fs/hpfs/super.c
> +++ b/fs/hpfs/super.c
> @@ -9,7 +9,8 @@
>  
>  #include "hpfs_fn.h"
>  #include <linux/module.h>
> -#include <linux/parser.h>
> +#include <linux/fs_context.h>
> +#include <linux/fs_parser.h>
>  #include <linux/init.h>
>  #include <linux/statfs.h>
>  #include <linux/magic.h>
> @@ -90,7 +91,7 @@ void hpfs_error(struct super_block *s, const char *fmt, ...)
>  	hpfs_sb(s)->sb_was_error = 1;
>  }
>  
> -/* 
> +/*
>   * A little trick to detect cycles in many hpfs structures and don't let the
>   * kernel crash on corrupted filesystem. When first called, set c2 to 0.
>   *
> @@ -272,146 +273,70 @@ static void destroy_inodecache(void)
>  	kmem_cache_destroy(hpfs_inode_cachep);
>  }
>  
> -/*
> - * A tiny parser for option strings, stolen from dosfs.
> - * Stolen again from read-only hpfs.
> - * And updated for table-driven option parsing.
> - */
> -
>  enum {
> -	Opt_help, Opt_uid, Opt_gid, Opt_umask, Opt_case_lower, Opt_case_asis,
> -	Opt_check_none, Opt_check_normal, Opt_check_strict,
> -	Opt_err_cont, Opt_err_ro, Opt_err_panic,
> -	Opt_eas_no, Opt_eas_ro, Opt_eas_rw,
> -	Opt_chkdsk_no, Opt_chkdsk_errors, Opt_chkdsk_always,
> -	Opt_timeshift, Opt_err,
> +	Opt_help, Opt_uid, Opt_gid, Opt_umask, Opt_case,
> +	Opt_check, Opt_err, Opt_eas, Opt_chkdsk, Opt_timeshift,
>  };
>  
> -static const match_table_t tokens = {
> -	{Opt_help, "help"},
> -	{Opt_uid, "uid=%u"},
> -	{Opt_gid, "gid=%u"},
> -	{Opt_umask, "umask=%o"},
> -	{Opt_case_lower, "case=lower"},
> -	{Opt_case_asis, "case=asis"},
> -	{Opt_check_none, "check=none"},
> -	{Opt_check_normal, "check=normal"},
> -	{Opt_check_strict, "check=strict"},
> -	{Opt_err_cont, "errors=continue"},
> -	{Opt_err_ro, "errors=remount-ro"},
> -	{Opt_err_panic, "errors=panic"},
> -	{Opt_eas_no, "eas=no"},
> -	{Opt_eas_ro, "eas=ro"},
> -	{Opt_eas_rw, "eas=rw"},
> -	{Opt_chkdsk_no, "chkdsk=no"},
> -	{Opt_chkdsk_errors, "chkdsk=errors"},
> -	{Opt_chkdsk_always, "chkdsk=always"},
> -	{Opt_timeshift, "timeshift=%d"},
> -	{Opt_err, NULL},
> +static const struct constant_table hpfs_param_case[] = {
> +	{"asis",	0},
> +	{"lower",	1},
> +	{}
>  };
>  
> -static int parse_opts(char *opts, kuid_t *uid, kgid_t *gid, umode_t *umask,
> -		      int *lowercase, int *eas, int *chk, int *errs,
> -		      int *chkdsk, int *timeshift)
> -{
> -	char *p;
> -	int option;
> +static const struct constant_table hpfs_param_check[] = {
> +	{"none",	0},
> +	{"normal",	1},
> +	{"strict",	2},
> +	{}
> +};
>  
> -	if (!opts)
> -		return 1;
> +static const struct constant_table hpfs_param_err[] = {
> +	{"continue",	0},
> +	{"remount-ro",	1},
> +	{"panic",	2},
> +	{}
> +};
>  
> -	/*pr_info("Parsing opts: '%s'\n",opts);*/
> -
> -	while ((p = strsep(&opts, ",")) != NULL) {
> -		substring_t args[MAX_OPT_ARGS];
> -		int token;
> -		if (!*p)
> -			continue;
> -
> -		token = match_token(p, tokens, args);
> -		switch (token) {
> -		case Opt_help:
> -			return 2;
> -		case Opt_uid:
> -			if (match_int(args, &option))
> -				return 0;
> -			*uid = make_kuid(current_user_ns(), option);
> -			if (!uid_valid(*uid))
> -				return 0;
> -			break;
> -		case Opt_gid:
> -			if (match_int(args, &option))
> -				return 0;
> -			*gid = make_kgid(current_user_ns(), option);
> -			if (!gid_valid(*gid))
> -				return 0;
> -			break;
> -		case Opt_umask:
> -			if (match_octal(args, &option))
> -				return 0;
> -			*umask = option;
> -			break;
> -		case Opt_case_lower:
> -			*lowercase = 1;
> -			break;
> -		case Opt_case_asis:
> -			*lowercase = 0;
> -			break;
> -		case Opt_check_none:
> -			*chk = 0;
> -			break;
> -		case Opt_check_normal:
> -			*chk = 1;
> -			break;
> -		case Opt_check_strict:
> -			*chk = 2;
> -			break;
> -		case Opt_err_cont:
> -			*errs = 0;
> -			break;
> -		case Opt_err_ro:
> -			*errs = 1;
> -			break;
> -		case Opt_err_panic:
> -			*errs = 2;
> -			break;
> -		case Opt_eas_no:
> -			*eas = 0;
> -			break;
> -		case Opt_eas_ro:
> -			*eas = 1;
> -			break;
> -		case Opt_eas_rw:
> -			*eas = 2;
> -			break;
> -		case Opt_chkdsk_no:
> -			*chkdsk = 0;
> -			break;
> -		case Opt_chkdsk_errors:
> -			*chkdsk = 1;
> -			break;
> -		case Opt_chkdsk_always:
> -			*chkdsk = 2;
> -			break;
> -		case Opt_timeshift:
> -		{
> -			int m = 1;
> -			char *rhs = args[0].from;
> -			if (!rhs || !*rhs)
> -				return 0;
> -			if (*rhs == '-') m = -1;
> -			if (*rhs == '+' || *rhs == '-') rhs++;
> -			*timeshift = simple_strtoul(rhs, &rhs, 0) * m;
> -			if (*rhs)
> -				return 0;
> -			break;
> -		}
> -		default:
> -			return 0;
> -		}
> -	}
> -	return 1;
> -}
> +static const struct constant_table hpfs_param_eas[] = {
> +	{"no",		0},
> +	{"ro",		1},
> +	{"rw",		2},
> +	{}
> +};
> +
> +static const struct constant_table hpfs_param_chkdsk[] = {
> +	{"no",		0},
> +	{"errors",	1},
> +	{"always",	2},
> +	{}
> +};
> +
> +static const struct fs_parameter_spec hpfs_param_spec[] = {
> +	fsparam_flag	("help",	Opt_help),
> +	fsparam_uid	("uid",		Opt_uid),
> +	fsparam_gid	("gid",		Opt_gid),
> +	fsparam_u32oct	("umask",	Opt_umask),
> +	fsparam_enum	("case",	Opt_case,	hpfs_param_case),
> +	fsparam_enum	("check",	Opt_check,	hpfs_param_check),
> +	fsparam_enum	("errors",	Opt_err,	hpfs_param_err),
> +	fsparam_enum	("eas",		Opt_eas,	hpfs_param_eas),
> +	fsparam_enum	("chkdsk",	Opt_chkdsk,	hpfs_param_chkdsk),
> +	fsparam_s32	("timeshift",	Opt_timeshift),
> +	{}
> +};
> +
> +struct hpfs_fc_context {
> +	kuid_t uid;
> +	kgid_t gid;
> +	umode_t umask;
> +	int lowercase;
> +	int eas;
> +	int chk;
> +	int errs;
> +	int chkdsk;
> +	int timeshift;
> +};
>  
>  static inline void hpfs_help(void)
>  {
> @@ -439,49 +364,92 @@ HPFS filesystem options:\n\
>  \n");
>  }
>  
> -static int hpfs_remount_fs(struct super_block *s, int *flags, char *data)
> +static int hpfs_parse_param(struct fs_context *fc, struct fs_parameter *param)
>  {
> -	kuid_t uid;
> -	kgid_t gid;
> -	umode_t umask;
> -	int lowercase, eas, chk, errs, chkdsk, timeshift;
> -	int o;
> +	struct hpfs_fc_context *ctx = fc->fs_private;
> +	struct fs_parse_result result;
> +	int opt;
> +
> +	opt = fs_parse(fc, hpfs_param_spec, param, &result);
> +	if (opt < 0)
> +		return opt;
> +
> +	switch (opt) {
> +	case Opt_help:
> +		hpfs_help();
> +		return -EINVAL;
> +	case Opt_uid:
> +		ctx->uid = result.uid;
> +		break;
> +	case Opt_gid:
> +		ctx->gid = result.gid;
> +		break;
> +	case Opt_umask:
> +		ctx->umask = result.uint_32;
> +		break;
> +	case Opt_case:
> +		ctx->lowercase = result.uint_32;
> +		break;
> +	case Opt_check:
> +		ctx->chk = result.uint_32;
> +		break;
> +	case Opt_err:
> +		ctx->errs = result.uint_32;
> +		break;
> +	case Opt_eas:
> +		ctx->eas = result.uint_32;
> +		break;
> +	case Opt_chkdsk:
> +		ctx->chkdsk = result.uint_32;
> +		break;
> +	case Opt_timeshift:
> +		{
> +			int m = 1;
> +			char *rhs = param->string;
> +			int timeshift;
> +
> +			if (*rhs == '-') m = -1;
> +			if (*rhs == '+' || *rhs == '-') rhs++;
> +			timeshift = simple_strtoul(rhs, &rhs, 0) * m;
> +			if (*rhs)
> +					return -EINVAL;
> +			ctx->timeshift = timeshift;
> +			break;
> +		}
> +	default:
> +		return -EINVAL;
> +	}
> +
> +	return 0;
> +}
> +
> +static int hpfs_reconfigure(struct fs_context *fc)
> +{
> +	struct hpfs_fc_context *ctx = fc->fs_private;
> +	struct super_block *s = fc->root->d_sb;
>  	struct hpfs_sb_info *sbi = hpfs_sb(s);
>  
>  	sync_filesystem(s);
>  
> -	*flags |= SB_NOATIME;
> +	fc->sb_flags |= SB_NOATIME;
>  
>  	hpfs_lock(s);
> -	uid = sbi->sb_uid; gid = sbi->sb_gid;
> -	umask = 0777 & ~sbi->sb_mode;
> -	lowercase = sbi->sb_lowercase;
> -	eas = sbi->sb_eas; chk = sbi->sb_chk; chkdsk = sbi->sb_chkdsk;
> -	errs = sbi->sb_err; timeshift = sbi->sb_timeshift;
> -
> -	if (!(o = parse_opts(data, &uid, &gid, &umask, &lowercase,
> -	    &eas, &chk, &errs, &chkdsk, &timeshift))) {
> -		pr_err("bad mount options.\n");
> -		goto out_err;
> -	}
> -	if (o == 2) {
> -		hpfs_help();
> -		goto out_err;
> -	}
> -	if (timeshift != sbi->sb_timeshift) {
> +
> +	if (ctx->timeshift != sbi->sb_timeshift) {
>  		pr_err("timeshift can't be changed using remount.\n");
>  		goto out_err;
>  	}
>  
>  	unmark_dirty(s);
>  
> -	sbi->sb_uid = uid; sbi->sb_gid = gid;
> -	sbi->sb_mode = 0777 & ~umask;
> -	sbi->sb_lowercase = lowercase;
> -	sbi->sb_eas = eas; sbi->sb_chk = chk; sbi->sb_chkdsk = chkdsk;
> -	sbi->sb_err = errs; sbi->sb_timeshift = timeshift;
> +	sbi->sb_uid = ctx->uid; sbi->sb_gid = ctx->gid;
> +	sbi->sb_mode = 0777 & ~ctx->umask;
> +	sbi->sb_lowercase = ctx->lowercase;
> +	sbi->sb_eas = ctx->eas; sbi->sb_chk = ctx->chk;
> +	sbi->sb_chkdsk = ctx->chkdsk;
> +	sbi->sb_err = ctx->errs; sbi->sb_timeshift = ctx->timeshift;
>  
> -	if (!(*flags & SB_RDONLY)) mark_dirty(s, 1);
> +	if (!(fc->sb_flags & SB_RDONLY)) mark_dirty(s, 1);
>  
>  	hpfs_unlock(s);
>  	return 0;
> @@ -530,30 +498,24 @@ static const struct super_operations hpfs_sops =
>  	.evict_inode	= hpfs_evict_inode,
>  	.put_super	= hpfs_put_super,
>  	.statfs		= hpfs_statfs,
> -	.remount_fs	= hpfs_remount_fs,
>  	.show_options	= hpfs_show_options,
>  };
>  
> -static int hpfs_fill_super(struct super_block *s, void *options, int silent)
> +static int hpfs_fill_super(struct super_block *s, struct fs_context *fc)
>  {
> +	struct hpfs_fc_context *ctx = fc->fs_private;
>  	struct buffer_head *bh0, *bh1, *bh2;
>  	struct hpfs_boot_block *bootblock;
>  	struct hpfs_super_block *superblock;
>  	struct hpfs_spare_block *spareblock;
>  	struct hpfs_sb_info *sbi;
>  	struct inode *root;
> -
> -	kuid_t uid;
> -	kgid_t gid;
> -	umode_t umask;
> -	int lowercase, eas, chk, errs, chkdsk, timeshift;
> +	int silent = fc->sb_flags & SB_SILENT;
>  
>  	dnode_secno root_dno;
>  	struct hpfs_dirent *de = NULL;
>  	struct quad_buffer_head qbh;
>  
> -	int o;
> -
>  	sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
>  	if (!sbi) {
>  		return -ENOMEM;
> @@ -563,26 +525,6 @@ static int hpfs_fill_super(struct super_block *s, void *options, int silent)
>  	mutex_init(&sbi->hpfs_mutex);
>  	hpfs_lock(s);
>  
> -	uid = current_uid();
> -	gid = current_gid();
> -	umask = current_umask();
> -	lowercase = 0;
> -	eas = 2;
> -	chk = 1;
> -	errs = 1;
> -	chkdsk = 1;
> -	timeshift = 0;
> -
> -	if (!(o = parse_opts(options, &uid, &gid, &umask, &lowercase,
> -	    &eas, &chk, &errs, &chkdsk, &timeshift))) {
> -		pr_err("bad mount options.\n");
> -		goto bail0;
> -	}
> -	if (o==2) {
> -		hpfs_help();
> -		goto bail0;
> -	}
> -
>  	/*sbi->sb_mounting = 1;*/
>  	sb_set_blocksize(s, 512);
>  	sbi->sb_fs_size = -1;
> @@ -622,17 +564,17 @@ static int hpfs_fill_super(struct super_block *s, void *options, int silent)
>  	sbi->sb_dirband_start = le32_to_cpu(superblock->dir_band_start);
>  	sbi->sb_dirband_size = le32_to_cpu(superblock->n_dir_band);
>  	sbi->sb_dmap = le32_to_cpu(superblock->dir_band_bitmap);
> -	sbi->sb_uid = uid;
> -	sbi->sb_gid = gid;
> -	sbi->sb_mode = 0777 & ~umask;
> +	sbi->sb_uid = ctx->uid;
> +	sbi->sb_gid = ctx->gid;
> +	sbi->sb_mode = 0777 & ~ctx->umask;
>  	sbi->sb_n_free = -1;
>  	sbi->sb_n_free_dnodes = -1;
> -	sbi->sb_lowercase = lowercase;
> -	sbi->sb_eas = eas;
> -	sbi->sb_chk = chk;
> -	sbi->sb_chkdsk = chkdsk;
> -	sbi->sb_err = errs;
> -	sbi->sb_timeshift = timeshift;
> +	sbi->sb_lowercase = ctx->lowercase;
> +	sbi->sb_eas = ctx->eas;
> +	sbi->sb_chk = ctx->chk;
> +	sbi->sb_chkdsk = ctx->chkdsk;
> +	sbi->sb_err = ctx->errs;
> +	sbi->sb_timeshift = ctx->timeshift;
>  	sbi->sb_was_error = 0;
>  	sbi->sb_cp_table = NULL;
>  	sbi->sb_c_bitmap = -1;
> @@ -653,7 +595,7 @@ static int hpfs_fill_super(struct super_block *s, void *options, int silent)
>  	
>  	/* Check for general fs errors*/
>  	if (spareblock->dirty && !spareblock->old_wrote) {
> -		if (errs == 2) {
> +		if (sbi->sb_err == 2) {
>  			pr_err("Improperly stopped, not mounted\n");
>  			goto bail4;
>  		}
> @@ -667,16 +609,16 @@ static int hpfs_fill_super(struct super_block *s, void *options, int silent)
>  	}
>  
>  	if (le32_to_cpu(spareblock->n_dnode_spares) != le32_to_cpu(spareblock->n_dnode_spares_free)) {
> -		if (errs >= 2) {
> +		if (sbi->sb_err >= 2) {
>  			pr_err("Spare dnodes used, try chkdsk\n");
>  			mark_dirty(s, 0);
>  			goto bail4;
>  		}
>  		hpfs_error(s, "warning: spare dnodes used, try chkdsk");
> -		if (errs == 0)
> +		if (sbi->sb_err == 0)
>  			pr_err("Proceeding, but your filesystem could be corrupted if you delete files or directories\n");
>  	}
> -	if (chk) {
> +	if (sbi->sb_chk) {
>  		unsigned a;
>  		if (le32_to_cpu(superblock->dir_band_end) - le32_to_cpu(superblock->dir_band_start) + 1 != le32_to_cpu(superblock->n_dir_band) ||
>  		    le32_to_cpu(superblock->dir_band_end) < le32_to_cpu(superblock->dir_band_start) || le32_to_cpu(superblock->n_dir_band) > 0x4000) {
> @@ -755,18 +697,70 @@ bail2:	brelse(bh0);
>  	return -EINVAL;
>  }
>  
> -static struct dentry *hpfs_mount(struct file_system_type *fs_type,
> -	int flags, const char *dev_name, void *data)
> +static int hpfs_get_tree(struct fs_context *fc)
> +{
> +	return get_tree_bdev(fc, hpfs_fill_super);
> +}
> +
> +static void hpfs_free_fc(struct fs_context *fc)
>  {
> -	return mount_bdev(fs_type, flags, dev_name, data, hpfs_fill_super);
> +	kfree(fc->fs_private);
>  }
>  
> +static const struct fs_context_operations hpfs_fc_context_ops = {
> +	.parse_param	= hpfs_parse_param,
> +	.get_tree	= hpfs_get_tree,
> +	.reconfigure	= hpfs_reconfigure,
> +	.free		= hpfs_free_fc,
> +};
> +
> +static int hpfs_init_fs_context(struct fs_context *fc)
> +{
> +	struct hpfs_fc_context *ctx;
> +
> +	ctx = kzalloc(sizeof(struct hpfs_fc_context), GFP_KERNEL);
> +	if (!ctx)
> +		return -ENOMEM;
> +
> +	if (fc->purpose == FS_CONTEXT_FOR_RECONFIGURE) {
> +		struct super_block *sb = fc->root->d_sb;
> +		struct hpfs_sb_info *sbi = hpfs_sb(sb);
> +
> +		ctx->uid = sbi->sb_uid;
> +		ctx->gid = sbi->sb_gid;
> +		ctx->umask = 0777 & ~sbi->sb_mode;
> +		ctx->lowercase = sbi->sb_lowercase;
> +		ctx->eas = sbi->sb_eas;
> +		ctx->chk = sbi->sb_chk;
> +		ctx->chkdsk = sbi->sb_chkdsk;
> +		ctx->errs = sbi->sb_err;
> +		ctx->timeshift = sbi->sb_timeshift;
> +
> +	} else {
> +		ctx->uid = current_uid();
> +		ctx->gid = current_gid();
> +		ctx->umask = current_umask();
> +		ctx->lowercase = 0;
> +		ctx->eas = 2;
> +		ctx->chk = 1;
> +		ctx->errs = 1;
> +		ctx->chkdsk = 1;
> +		ctx->timeshift = 0;
> +	}
> +
> +	fc->fs_private = ctx;
> +	fc->ops = &hpfs_fc_context_ops;
> +
> +	return 0;
> +};
> +
>  static struct file_system_type hpfs_fs_type = {
>  	.owner		= THIS_MODULE,
>  	.name		= "hpfs",
> -	.mount		= hpfs_mount,
>  	.kill_sb	= kill_block_super,
>  	.fs_flags	= FS_REQUIRES_DEV,
> +	.init_fs_context = hpfs_init_fs_context,
> +	.parameters	= hpfs_param_spec,
>  };
>  MODULE_ALIAS_FS("hpfs");
>