Unverified Commit e8fe0d4b authored by Christian Brauner's avatar Christian Brauner
Browse files

Merge patch series "fs: last of the pseudofs mount api conversions" 

Eric Sandeen <sandeen@redhat.com> says:

pstore used mount_single, which used to transparently do a
remount operation on a fresh mount of an existing superblock.
The new get_tree_single does not do this, but prior discussion
on fsdevel seems to indicate that this isn't expected to be a
problem. We can watch for issues.

devpts is just a forward port from work dhowells did already, and it
seems straightforward. I left error messages as they are rather than
converting to the mount API message channel for now.

devtmpfs was already converted, but left a .mount in place, rather
than using .get_tree. The solution to this is ... unique so some
scrutiny is probably wise.

The last patch removes reconfigure_single, mount_single, and
compare_single because no users remain, but we could also wait until
all conversions are done, and remove all infrastructure at that time
instead, if desired.

* patches from https://lore.kernel.org/r/20250205213931.74614-1-sandeen@redhat.com:
  vfs: remove some unused old mount api code
  devtmpfs: replace ->mount with ->get_tree in public instance
  vfs: Convert devpts to use the new mount API
  pstore: convert to the new mount API

Link: https://lore.kernel.org/r/20250205213931.74614-1-sandeen@redhat.com


Signed-off-by: default avatarChristian Brauner <brauner@kernel.org>
parents 2014c95a bdfa77e7

drivers/base/devtmpfs.c

+64 −17
Original line number Diff line number Diff line
@@ -63,22 +63,6 @@ __setup("devtmpfs.mount=", mount_param); 


static struct vfsmount *mnt;



static struct dentry *public_dev_mount(struct file_system_type *fs_type, int flags,

		      const char *dev_name, void *data)

{

	struct super_block *s = mnt->mnt_sb;

	int err;



	atomic_inc(&s->s_active);

	down_write(&s->s_umount);

	err = reconfigure_single(s, flags, data);

	if (err < 0) {

		deactivate_locked_super(s);

		return ERR_PTR(err);

	}

	return dget(s->s_root);

}



static struct file_system_type internal_fs_type = {

	.name = "devtmpfs",

#ifdef CONFIG_TMPFS
@@ -89,9 +73,40 @@ static struct file_system_type internal_fs_type = { 
	.kill_sb = kill_litter_super,

};



/* Simply take a ref on the existing mount */

static int devtmpfs_get_tree(struct fs_context *fc)

{

	struct super_block *sb = mnt->mnt_sb;



	atomic_inc(&sb->s_active);

	down_write(&sb->s_umount);

	fc->root = dget(sb->s_root);

	return 0;

}



/* Ops are filled in during init depending on underlying shmem or ramfs type */

struct fs_context_operations devtmpfs_context_ops = {};



/* Call the underlying initialization and set to our ops */

static int devtmpfs_init_fs_context(struct fs_context *fc)

{

	int ret;

#ifdef CONFIG_TMPFS

	ret = shmem_init_fs_context(fc);

#else

	ret = ramfs_init_fs_context(fc);

#endif

	if (ret < 0)

		return ret;



	fc->ops = &devtmpfs_context_ops;



	return 0;

}



static struct file_system_type dev_fs_type = {

	.name = "devtmpfs",

	.mount = public_dev_mount,

	.init_fs_context = devtmpfs_init_fs_context,

};



static int devtmpfs_submit_req(struct req *req, const char *tmp)
@@ -442,6 +457,31 @@ static int __ref devtmpfsd(void *p) 
	return 0;

}



/*

 * Get the underlying (shmem/ramfs) context ops to build ours

 */

static int devtmpfs_configure_context(void)

{

	struct fs_context *fc;



	fc = fs_context_for_reconfigure(mnt->mnt_root, mnt->mnt_sb->s_flags,

					MS_RMT_MASK);

	if (IS_ERR(fc))

		return PTR_ERR(fc);



	/* Set up devtmpfs_context_ops based on underlying type */

	devtmpfs_context_ops.free	      = fc->ops->free;

	devtmpfs_context_ops.dup	      = fc->ops->dup;

	devtmpfs_context_ops.parse_param      = fc->ops->parse_param;

	devtmpfs_context_ops.parse_monolithic = fc->ops->parse_monolithic;

	devtmpfs_context_ops.get_tree	      = &devtmpfs_get_tree;

	devtmpfs_context_ops.reconfigure      = fc->ops->reconfigure;



	put_fs_context(fc);



	return 0;

}



/*

 * Create devtmpfs instance, driver-core devices will add their device

 * nodes here.
@@ -456,6 +496,13 @@ int __init devtmpfs_init(void) 
		pr_err("unable to create devtmpfs %ld\n", PTR_ERR(mnt));

		return PTR_ERR(mnt);

	}



	err = devtmpfs_configure_context();

	if (err) {

		pr_err("unable to configure devtmpfs type %d\n", err);

		return err;

	}



	err = register_filesystem(&dev_fs_type);

	if (err) {

		pr_err("unable to register devtmpfs type %d\n", err);

fs/devpts/inode.c

+110 −141
Original line number Diff line number Diff line
@@ -12,6 +12,8 @@ 
#include <linux/module.h>

#include <linux/init.h>

#include <linux/fs.h>

#include <linux/fs_context.h>

#include <linux/fs_parser.h>

#include <linux/sched.h>

#include <linux/namei.h>

#include <linux/slab.h>
@@ -21,7 +23,6 @@ 
#include <linux/magic.h>

#include <linux/idr.h>

#include <linux/devpts_fs.h>

#include <linux/parser.h>

#include <linux/fsnotify.h>

#include <linux/seq_file.h>
@@ -87,14 +88,14 @@ enum { 
	Opt_err

};



static const match_table_t tokens = {

	{Opt_uid, "uid=%u"},

	{Opt_gid, "gid=%u"},

	{Opt_mode, "mode=%o"},

	{Opt_ptmxmode, "ptmxmode=%o"},

	{Opt_newinstance, "newinstance"},

	{Opt_max, "max=%d"},

	{Opt_err, NULL}

static const struct fs_parameter_spec devpts_param_specs[] = {

	fsparam_u32	("gid",		Opt_gid),

	fsparam_s32	("max",		Opt_max),

	fsparam_u32oct	("mode",	Opt_mode),

	fsparam_flag	("newinstance",	Opt_newinstance),

	fsparam_u32oct	("ptmxmode",	Opt_ptmxmode),

	fsparam_u32	("uid",		Opt_uid),

	{}

};



struct pts_fs_info {
@@ -214,93 +215,48 @@ void devpts_release(struct pts_fs_info *fsi) 
	deactivate_super(fsi->sb);

}



#define PARSE_MOUNT	0

#define PARSE_REMOUNT	1



/*

 * parse_mount_options():

 *	Set @opts to mount options specified in @data. If an option is not

 *	specified in @data, set it to its default value.

 *

 * Note: @data may be NULL (in which case all options are set to default).

 * devpts_parse_param - Parse mount parameters

 */

static int parse_mount_options(char *data, int op, struct pts_mount_opts *opts)

static int devpts_parse_param(struct fs_context *fc, struct fs_parameter *param)

{

	char *p;

	kuid_t uid;

	kgid_t gid;



	opts->setuid  = 0;

	opts->setgid  = 0;

	opts->uid     = GLOBAL_ROOT_UID;

	opts->gid     = GLOBAL_ROOT_GID;

	opts->mode    = DEVPTS_DEFAULT_MODE;

	opts->ptmxmode = DEVPTS_DEFAULT_PTMX_MODE;

	opts->max     = NR_UNIX98_PTY_MAX;



	/* Only allow instances mounted from the initial mount

	 * namespace to tap the reserve pool of ptys.

	 */

	if (op == PARSE_MOUNT)

		opts->reserve =

			(current->nsproxy->mnt_ns == init_task.nsproxy->mnt_ns);



	while ((p = strsep(&data, ",")) != NULL) {

		substring_t args[MAX_OPT_ARGS];

		int token;

		int option;

	struct pts_fs_info *fsi = fc->s_fs_info;

	struct pts_mount_opts *opts = &fsi->mount_opts;

	struct fs_parse_result result;

	int opt;



		if (!*p)

			continue;

	opt = fs_parse(fc, devpts_param_specs, param, &result);

	if (opt < 0)

		return opt;



		token = match_token(p, tokens, args);

		switch (token) {

	switch (opt) {

	case Opt_uid:

			if (match_int(&args[0], &option))

				return -EINVAL;

			uid = make_kuid(current_user_ns(), option);

			if (!uid_valid(uid))

				return -EINVAL;

			opts->uid = uid;

		opts->uid = result.uid;

		opts->setuid = 1;

		break;

	case Opt_gid:

			if (match_int(&args[0], &option))

				return -EINVAL;

			gid = make_kgid(current_user_ns(), option);

			if (!gid_valid(gid))

				return -EINVAL;

			opts->gid = gid;

		opts->gid = result.gid;

		opts->setgid = 1;

		break;

	case Opt_mode:

			if (match_octal(&args[0], &option))

				return -EINVAL;

			opts->mode = option & S_IALLUGO;

		opts->mode = result.uint_32 & S_IALLUGO;

		break;

	case Opt_ptmxmode:

			if (match_octal(&args[0], &option))

				return -EINVAL;

			opts->ptmxmode = option & S_IALLUGO;

		opts->ptmxmode = result.uint_32 & S_IALLUGO;

		break;

	case Opt_newinstance:

		break;

	case Opt_max:

			if (match_int(&args[0], &option) ||

			    option < 0 || option > NR_UNIX98_PTY_MAX)

				return -EINVAL;

			opts->max = option;

		if (result.uint_32 > NR_UNIX98_PTY_MAX)

			return invalf(fc, "max out of range");

		opts->max = result.uint_32;

		break;

		default:

			pr_err("called with bogus options\n");

			return -EINVAL;

		}

	}



	return 0;

}



static int mknod_ptmx(struct super_block *sb)

static int mknod_ptmx(struct super_block *sb, struct fs_context *fc)

{

	int mode;

	int rc = -ENOMEM;
@@ -362,13 +318,23 @@ static void update_ptmx_mode(struct pts_fs_info *fsi) 
	}

}



static int devpts_remount(struct super_block *sb, int *flags, char *data)

static int devpts_reconfigure(struct fs_context *fc)

{

	int err;

	struct pts_fs_info *fsi = DEVPTS_SB(sb);

	struct pts_mount_opts *opts = &fsi->mount_opts;

	struct pts_fs_info *fsi = DEVPTS_SB(fc->root->d_sb);

	struct pts_fs_info *new = fc->s_fs_info;



	err = parse_mount_options(data, PARSE_REMOUNT, opts);

	/* Apply the revised options.  We don't want to change ->reserve.

	 * Ideally, we'd update each option conditionally on it having been

	 * explicitly changed, but the default is to reset everything so that

	 * would break UAPI...

	 */

	fsi->mount_opts.setuid		= new->mount_opts.setuid;

	fsi->mount_opts.setgid		= new->mount_opts.setgid;

	fsi->mount_opts.uid		= new->mount_opts.uid;

	fsi->mount_opts.gid		= new->mount_opts.gid;

	fsi->mount_opts.mode		= new->mount_opts.mode;

	fsi->mount_opts.ptmxmode	= new->mount_opts.ptmxmode;

	fsi->mount_opts.max		= new->mount_opts.max;



	/*

	 * parse_mount_options() restores options to default values
@@ -378,7 +344,7 @@ static int devpts_remount(struct super_block *sb, int *flags, char *data) 
	 */

	update_ptmx_mode(fsi);



	return err;

	return 0;

}



static int devpts_show_options(struct seq_file *seq, struct dentry *root)
@@ -402,31 +368,13 @@ static int devpts_show_options(struct seq_file *seq, struct dentry *root) 


static const struct super_operations devpts_sops = {

	.statfs		= simple_statfs,

	.remount_fs	= devpts_remount,

	.show_options	= devpts_show_options,

};



static void *new_pts_fs_info(struct super_block *sb)

{

	struct pts_fs_info *fsi;



	fsi = kzalloc(sizeof(struct pts_fs_info), GFP_KERNEL);

	if (!fsi)

		return NULL;



	ida_init(&fsi->allocated_ptys);

	fsi->mount_opts.mode = DEVPTS_DEFAULT_MODE;

	fsi->mount_opts.ptmxmode = DEVPTS_DEFAULT_PTMX_MODE;

	fsi->sb = sb;



	return fsi;

}



static int

devpts_fill_super(struct super_block *s, void *data, int silent)

static int devpts_fill_super(struct super_block *s, struct fs_context *fc)

{

	struct pts_fs_info *fsi = DEVPTS_SB(s);

	struct inode *inode;

	int error;



	s->s_iflags &= ~SB_I_NODEV;

	s->s_blocksize = 1024;
@@ -435,20 +383,11 @@ devpts_fill_super(struct super_block *s, void *data, int silent) 
	s->s_op = &devpts_sops;

	s->s_d_op = &simple_dentry_operations;

	s->s_time_gran = 1;

	fsi->sb = s;



	error = -ENOMEM;

	s->s_fs_info = new_pts_fs_info(s);

	if (!s->s_fs_info)

		goto fail;



	error = parse_mount_options(data, PARSE_MOUNT, &DEVPTS_SB(s)->mount_opts);

	if (error)

		goto fail;



	error = -ENOMEM;

	inode = new_inode(s);

	if (!inode)

		goto fail;

		return -ENOMEM;

	inode->i_ino = 1;

	simple_inode_init_ts(inode);

	inode->i_mode = S_IFDIR | S_IRUGO | S_IXUGO | S_IWUSR;
@@ -459,31 +398,60 @@ devpts_fill_super(struct super_block *s, void *data, int silent) 
	s->s_root = d_make_root(inode);

	if (!s->s_root) {

		pr_err("get root dentry failed\n");

		goto fail;

		return -ENOMEM;

	}



	error = mknod_ptmx(s);

	if (error)

		goto fail_dput;



	return 0;

fail_dput:

	dput(s->s_root);

	s->s_root = NULL;

fail:

	return error;

	return mknod_ptmx(s, fc);

}



/*

 * devpts_mount()

 * devpts_get_tree()

 *

 *     Mount a new (private) instance of devpts.  PTYs created in this

 *     instance are independent of the PTYs in other devpts instances.

 */

static struct dentry *devpts_mount(struct file_system_type *fs_type,

	int flags, const char *dev_name, void *data)

static int devpts_get_tree(struct fs_context *fc)

{

	return get_tree_nodev(fc, devpts_fill_super);

}



static void devpts_free_fc(struct fs_context *fc)

{

	return mount_nodev(fs_type, flags, data, devpts_fill_super);

	kfree(fc->s_fs_info);

}



static const struct fs_context_operations devpts_context_ops = {

	.free		= devpts_free_fc,

	.parse_param	= devpts_parse_param,

	.get_tree	= devpts_get_tree,

	.reconfigure	= devpts_reconfigure,

};



/*

 * Set up the filesystem mount context.

 */

static int devpts_init_fs_context(struct fs_context *fc)

{

	struct pts_fs_info *fsi;



	fsi = kzalloc(sizeof(struct pts_fs_info), GFP_KERNEL);

	if (!fsi)

		return -ENOMEM;



	ida_init(&fsi->allocated_ptys);

	fsi->mount_opts.uid     = GLOBAL_ROOT_UID;

	fsi->mount_opts.gid     = GLOBAL_ROOT_GID;

	fsi->mount_opts.mode    = DEVPTS_DEFAULT_MODE;

	fsi->mount_opts.ptmxmode = DEVPTS_DEFAULT_PTMX_MODE;

	fsi->mount_opts.max     = NR_UNIX98_PTY_MAX;



	if (fc->purpose == FS_CONTEXT_FOR_MOUNT &&

	    current->nsproxy->mnt_ns == init_task.nsproxy->mnt_ns)

		fsi->mount_opts.reserve = true;



	fc->s_fs_info = fsi;

	fc->ops = &devpts_context_ops;

	return 0;

}



static void devpts_kill_sb(struct super_block *sb)
@@ -498,7 +466,8 @@ static void devpts_kill_sb(struct super_block *sb) 


static struct file_system_type devpts_fs_type = {

	.name		= "devpts",

	.mount		= devpts_mount,

	.init_fs_context = devpts_init_fs_context,

	.parameters	= devpts_param_specs,

	.kill_sb	= devpts_kill_sb,

	.fs_flags	= FS_USERNS_MOUNT,

};

fs/pstore/inode.c

+74 −35
Original line number Diff line number Diff line
@@ -14,10 +14,10 @@ 
#include <linux/init.h>

#include <linux/list.h>

#include <linux/string.h>

#include <linux/mount.h>

#include <linux/seq_file.h>

#include <linux/ramfs.h>

#include <linux/parser.h>

#include <linux/fs_parser.h>

#include <linux/fs_context.h>

#include <linux/sched.h>

#include <linux/magic.h>

#include <linux/pstore.h>
@@ -226,37 +226,38 @@ static struct inode *pstore_get_inode(struct super_block *sb) 
}



enum {

	Opt_kmsg_bytes, Opt_err

	Opt_kmsg_bytes

};



static const match_table_t tokens = {

	{Opt_kmsg_bytes, "kmsg_bytes=%u"},

	{Opt_err, NULL}

static const struct fs_parameter_spec pstore_param_spec[] = {

	fsparam_u32	("kmsg_bytes",	Opt_kmsg_bytes),

	{}

};



static void parse_options(char *options)

{

	char		*p;

	substring_t	args[MAX_OPT_ARGS];

	int		option;



	if (!options)

		return;

struct pstore_context {

	unsigned int kmsg_bytes;

};



	while ((p = strsep(&options, ",")) != NULL) {

		int token;

static int pstore_parse_param(struct fs_context *fc, struct fs_parameter *param)

{

	struct pstore_context *ctx = fc->fs_private;

	struct fs_parse_result result;

	int opt;



		if (!*p)

			continue;

	opt = fs_parse(fc, pstore_param_spec, param, &result);

	/* pstore has historically ignored invalid kmsg_bytes param */

	if (opt < 0)

		return 0;



		token = match_token(p, tokens, args);

		switch (token) {

	switch (opt) {

	case Opt_kmsg_bytes:

			if (!match_int(&args[0], &option))

				pstore_set_kmsg_bytes(option);

		ctx->kmsg_bytes = result.uint_32;

		break;

	default:

		return -EINVAL;

	}

	}



	return 0;

}



/*
@@ -269,10 +270,12 @@ static int pstore_show_options(struct seq_file *m, struct dentry *root) 
	return 0;

}



static int pstore_remount(struct super_block *sb, int *flags, char *data)

static int pstore_reconfigure(struct fs_context *fc)

{

	sync_filesystem(sb);

	parse_options(data);

	struct pstore_context *ctx = fc->fs_private;



	sync_filesystem(fc->root->d_sb);

	pstore_set_kmsg_bytes(ctx->kmsg_bytes);



	return 0;

}
@@ -281,7 +284,6 @@ static const struct super_operations pstore_ops = { 
	.statfs		= simple_statfs,

	.drop_inode	= generic_delete_inode,

	.evict_inode	= pstore_evict_inode,

	.remount_fs	= pstore_remount,

	.show_options	= pstore_show_options,

};
@@ -406,8 +408,9 @@ void pstore_get_records(int quiet) 
	inode_unlock(d_inode(root));

}



static int pstore_fill_super(struct super_block *sb, void *data, int silent)

static int pstore_fill_super(struct super_block *sb, struct fs_context *fc)

{

	struct pstore_context *ctx = fc->fs_private;

	struct inode *inode;



	sb->s_maxbytes		= MAX_LFS_FILESIZE;
@@ -417,7 +420,7 @@ static int pstore_fill_super(struct super_block *sb, void *data, int silent) 
	sb->s_op		= &pstore_ops;

	sb->s_time_gran		= 1;



	parse_options(data);

	pstore_set_kmsg_bytes(ctx->kmsg_bytes);



	inode = pstore_get_inode(sb);

	if (inode) {
@@ -438,12 +441,26 @@ static int pstore_fill_super(struct super_block *sb, void *data, int silent) 
	return 0;

}



static struct dentry *pstore_mount(struct file_system_type *fs_type,

	int flags, const char *dev_name, void *data)

static int pstore_get_tree(struct fs_context *fc)

{

	if (fc->root)

		return pstore_reconfigure(fc);



	return get_tree_single(fc, pstore_fill_super);

}



static void pstore_free_fc(struct fs_context *fc)

{

	return mount_single(fs_type, flags, data, pstore_fill_super);

	kfree(fc->fs_private);

}



static const struct fs_context_operations pstore_context_ops = {

	.parse_param	= pstore_parse_param,

	.get_tree	= pstore_get_tree,

	.reconfigure	= pstore_reconfigure,

	.free		= pstore_free_fc,

};



static void pstore_kill_sb(struct super_block *sb)

{

	guard(mutex)(&pstore_sb_lock);
@@ -456,11 +473,33 @@ static void pstore_kill_sb(struct super_block *sb) 
	INIT_LIST_HEAD(&records_list);

}



static int pstore_init_fs_context(struct fs_context *fc)

{

	struct pstore_context *ctx;



	ctx = kzalloc(sizeof(struct pstore_context), GFP_KERNEL);

	if (!ctx)

		return -ENOMEM;



	/*

	 * Global kmsg_bytes is initialized to default, and updated

	 * every time we (re)mount the single-sb filesystem with the

	 * option specified.

	 */

	ctx->kmsg_bytes = kmsg_bytes;



	fc->fs_private = ctx;

	fc->ops = &pstore_context_ops;



	return 0;

}



static struct file_system_type pstore_fs_type = {

	.owner          = THIS_MODULE,

	.name		= "pstore",

	.mount		= pstore_mount,

	.kill_sb	= pstore_kill_sb,

	.init_fs_context = pstore_init_fs_context,

	.parameters	= pstore_param_spec,

};



int __init pstore_init_fs(void)

fs/super.c

+0 −55
Original line number Diff line number Diff line
@@ -1737,61 +1737,6 @@ struct dentry *mount_nodev(struct file_system_type *fs_type, 
}

EXPORT_SYMBOL(mount_nodev);



int reconfigure_single(struct super_block *s,

		       int flags, void *data)

{

	struct fs_context *fc;

	int ret;



	/* The caller really need to be passing fc down into mount_single(),

	 * then a chunk of this can be removed.  [Bollocks -- AV]

	 * Better yet, reconfiguration shouldn't happen, but rather the second

	 * mount should be rejected if the parameters are not compatible.

	 */

	fc = fs_context_for_reconfigure(s->s_root, flags, MS_RMT_MASK);

	if (IS_ERR(fc))

		return PTR_ERR(fc);



	ret = parse_monolithic_mount_data(fc, data);

	if (ret < 0)

		goto out;



	ret = reconfigure_super(fc);

out:

	put_fs_context(fc);

	return ret;

}



static int compare_single(struct super_block *s, void *p)

{

	return 1;

}



struct dentry *mount_single(struct file_system_type *fs_type,

	int flags, void *data,

	int (*fill_super)(struct super_block *, void *, int))

{

	struct super_block *s;

	int error;



	s = sget(fs_type, compare_single, set_anon_super, flags, NULL);

	if (IS_ERR(s))

		return ERR_CAST(s);

	if (!s->s_root) {

		error = fill_super(s, data, flags & SB_SILENT ? 1 : 0);

		if (!error)

			s->s_flags |= SB_ACTIVE;

	} else {

		error = reconfigure_single(s, flags, data);

	}

	if (unlikely(error)) {

		deactivate_locked_super(s);

		return ERR_PTR(error);

	}

	return dget(s->s_root);

}

EXPORT_SYMBOL(mount_single);



/**

 * vfs_get_tree - Get the mountable root

 * @fc: The superblock configuration context.

include/linux/fs.h

+0 −3
Original line number Diff line number Diff line
@@ -2641,9 +2641,6 @@ static inline bool is_mgtime(const struct inode *inode) 
extern struct dentry *mount_bdev(struct file_system_type *fs_type,

	int flags, const char *dev_name, void *data,

	int (*fill_super)(struct super_block *, void *, int));

extern struct dentry *mount_single(struct file_system_type *fs_type,

	int flags, void *data,

	int (*fill_super)(struct super_block *, void *, int));

extern struct dentry *mount_nodev(struct file_system_type *fs_type,

	int flags, void *data,

	int (*fill_super)(struct super_block *, void *, int));