Commit e6ec453b authored by Ian Kent's avatar Ian Kent Committed by Christian Brauner
Browse files

autofs: convert autofs to use the new mount api 



Convert the autofs filesystem to use the mount API.

The conversion patch was originally written by David Howells.
I have taken that patch and broken it into several patches in an effort
to make the change easier to review.

Signed-off-by: default avatarIan Kent <raven@themaw.net>
Reviewed-by: default avatarBill O'Donnell <bodonnel@redhat.com>
Message-Id: <20230922041215.13675-8-raven@themaw.net>
Signed-off-by: default avatarChristian Brauner <brauner@kernel.org>
parent 1f50012d

fs/autofs/autofs_i.h

+4 −1
Original line number Diff line number Diff line
@@ -25,6 +25,8 @@ 
#include <linux/completion.h>

#include <linux/file.h>

#include <linux/magic.h>

#include <linux/fs_context.h>

#include <linux/fs_parser.h>



/* This is the range of ioctl() numbers we claim as ours */

#define AUTOFS_IOC_FIRST     AUTOFS_IOC_READY
@@ -205,7 +207,8 @@ static inline void managed_dentry_clear_managed(struct dentry *dentry) 


/* Initializing function */



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

extern const struct fs_parameter_spec autofs_param_specs[];

int autofs_init_fs_context(struct fs_context *fc);

struct autofs_info *autofs_new_ino(struct autofs_sb_info *);

void autofs_clean_ino(struct autofs_info *);

fs/autofs/init.c

+2 −7
Original line number Diff line number Diff line
@@ -7,16 +7,11 @@ 
#include <linux/init.h>

#include "autofs_i.h"



static struct dentry *autofs_mount(struct file_system_type *fs_type,

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

{

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

}



struct file_system_type autofs_fs_type = {

	.owner		= THIS_MODULE,

	.name		= "autofs",

	.mount		= autofs_mount,

	.init_fs_context = autofs_init_fs_context,

	.parameters	= autofs_param_specs,

	.kill_sb	= autofs_kill_sb,

};

MODULE_ALIAS_FS("autofs");

fs/autofs/inode.c

+149 −116
Original line number Diff line number Diff line
@@ -6,7 +6,6 @@ 


#include <linux/seq_file.h>

#include <linux/pagemap.h>

#include <linux/parser.h>



#include "autofs_i.h"
@@ -111,7 +110,6 @@ static const struct super_operations autofs_sops = { 
};



enum {

	Opt_err,

	Opt_direct,

	Opt_fd,

	Opt_gid,
@@ -125,35 +123,56 @@ enum { 
	Opt_uid,

};



static const match_table_t tokens = {

	{Opt_fd, "fd=%u"},

	{Opt_uid, "uid=%u"},

	{Opt_gid, "gid=%u"},

	{Opt_pgrp, "pgrp=%u"},

	{Opt_minproto, "minproto=%u"},

	{Opt_maxproto, "maxproto=%u"},

	{Opt_indirect, "indirect"},

	{Opt_direct, "direct"},

	{Opt_offset, "offset"},

	{Opt_strictexpire, "strictexpire"},

	{Opt_ignore, "ignore"},

	{Opt_err, NULL}

const struct fs_parameter_spec autofs_param_specs[] = {

	fsparam_flag	("direct",		Opt_direct),

	fsparam_fd	("fd",			Opt_fd),

	fsparam_u32	("gid",			Opt_gid),

	fsparam_flag	("ignore",		Opt_ignore),

	fsparam_flag	("indirect",		Opt_indirect),

	fsparam_u32	("maxproto",		Opt_maxproto),

	fsparam_u32	("minproto",		Opt_minproto),

	fsparam_flag	("offset",		Opt_offset),

	fsparam_u32	("pgrp",		Opt_pgrp),

	fsparam_flag	("strictexpire",	Opt_strictexpire),

	fsparam_u32	("uid",			Opt_uid),

	{}

};



static int autofs_parse_fd(struct autofs_sb_info *sbi, int fd)

struct autofs_fs_context {

	kuid_t	uid;

	kgid_t	gid;

	int	pgrp;

	bool	pgrp_set;

};



/*

 * Open the fd.  We do it here rather than in get_tree so that it's done in the

 * context of the system call that passed the data and not the one that

 * triggered the superblock creation, lest the fd gets reassigned.

 */

static int autofs_parse_fd(struct fs_context *fc, struct autofs_sb_info *sbi,

			   struct fs_parameter *param,

			   struct fs_parse_result *result)

{

	struct file *pipe;

	int ret;



	pipe = fget(fd);

	if (param->type == fs_value_is_file) {

		/* came through the new api */

		pipe = param->file;

		param->file = NULL;

	} else {

		pipe = fget(result->uint_32);

	}

	if (!pipe) {

		pr_err("could not open pipe file descriptor\n");

		errorf(fc, "could not open pipe file descriptor");

		return -EBADF;

	}



	ret = autofs_check_pipe(pipe);

	if (ret < 0) {

		pr_err("Invalid/unusable pipe\n");

		errorf(fc, "Invalid/unusable pipe");

		if (param->type != fs_value_is_file)

			fput(pipe);

		return -EBADF;

	}
@@ -161,64 +180,49 @@ static int autofs_parse_fd(struct autofs_sb_info *sbi, int fd) 
	if (sbi->pipe)

		fput(sbi->pipe);



	sbi->pipefd = fd;

	sbi->pipefd = result->uint_32;

	sbi->pipe = pipe;



	return 0;

}



static int autofs_parse_param(char *optstr, struct inode *root,

			      int *pgrp, bool *pgrp_set,

			      struct autofs_sb_info *sbi)

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

{

	substring_t args[MAX_OPT_ARGS];

	int option;

	int pipefd = -1;

	struct autofs_fs_context *ctx = fc->fs_private;

	struct autofs_sb_info *sbi = fc->s_fs_info;

	struct fs_parse_result result;

	kuid_t uid;

	kgid_t gid;

	int token;

	int ret;

	int opt;



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

	if (opt < 0)

		return opt;



	token = match_token(optstr, tokens, args);

	switch (token) {

	switch (opt) {

	case Opt_fd:

		if (match_int(args, &pipefd))

			return 1;

		ret = autofs_parse_fd(sbi, pipefd);

		if (ret)

			return 1;

		break;

		return autofs_parse_fd(fc, sbi, param, &result);

	case Opt_uid:

		if (match_int(args, &option))

			return 1;

		uid = make_kuid(current_user_ns(), option);

		uid = make_kuid(current_user_ns(), result.uint_32);

		if (!uid_valid(uid))

			return 1;

		root->i_uid = uid;

			return invalfc(fc, "Invalid uid");

		ctx->uid = uid;

		break;

	case Opt_gid:

		if (match_int(args, &option))

			return 1;

		gid = make_kgid(current_user_ns(), option);

		gid = make_kgid(current_user_ns(), result.uint_32);

		if (!gid_valid(gid))

			return 1;

		root->i_gid = gid;

			return invalfc(fc, "Invalid gid");

		ctx->gid = gid;

		break;

	case Opt_pgrp:

		if (match_int(args, &option))

			return 1;

		*pgrp = option;

		*pgrp_set = true;

		ctx->pgrp = result.uint_32;

		ctx->pgrp_set = true;

		break;

	case Opt_minproto:

		if (match_int(args, &option))

			return 1;

		sbi->min_proto = option;

		sbi->min_proto = result.uint_32;

		break;

	case Opt_maxproto:

		if (match_int(args, &option))

			return 1;

		sbi->max_proto = option;

		sbi->max_proto = result.uint_32;

		break;

	case Opt_indirect:

		set_autofs_type_indirect(&sbi->type);
@@ -239,29 +243,6 @@ static int autofs_parse_param(char *optstr, struct inode *root, 
	return 0;

}



static int parse_options(char *options,

			 struct inode *root, int *pgrp, bool *pgrp_set,

			 struct autofs_sb_info *sbi)

{

	char *p;



	root->i_uid = current_uid();

	root->i_gid = current_gid();



	if (!options)

		return 1;



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

		if (!*p)

			continue;



		if (autofs_parse_param(p, root, pgrp, pgrp_set, sbi))

			return 1;

	}



	return (sbi->pipefd < 0);

}



static struct autofs_sb_info *autofs_alloc_sbi(void)

{

	struct autofs_sb_info *sbi;
@@ -287,12 +268,14 @@ static struct autofs_sb_info *autofs_alloc_sbi(void) 
	return sbi;

}



static int autofs_validate_protocol(struct autofs_sb_info *sbi)

static int autofs_validate_protocol(struct fs_context *fc)

{

	struct autofs_sb_info *sbi = fc->s_fs_info;



	/* Test versions first */

	if (sbi->max_proto < AUTOFS_MIN_PROTO_VERSION ||

	    sbi->min_proto > AUTOFS_MAX_PROTO_VERSION) {

		pr_err("kernel does not match daemon version "

		errorf(fc, "kernel does not match daemon version "

		       "daemon (%d, %d) kernel (%d, %d)\n",

		       sbi->min_proto, sbi->max_proto,

		       AUTOFS_MIN_PROTO_VERSION, AUTOFS_MAX_PROTO_VERSION);
@@ -309,24 +292,18 @@ static int autofs_validate_protocol(struct autofs_sb_info *sbi) 
	return 0;

}



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

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

{

	struct autofs_fs_context *ctx = fc->fs_private;

	struct autofs_sb_info *sbi = s->s_fs_info;

	struct inode *root_inode;

	struct dentry *root;

	struct autofs_sb_info *sbi;

	struct autofs_info *ino;

	int pgrp = 0;

	bool pgrp_set = false;

	int ret = -EINVAL;



	sbi = autofs_alloc_sbi();

	if (!sbi)

		return -ENOMEM;

	int ret = -ENOMEM;



	pr_debug("starting up, sbi = %p\n", sbi);



	sbi->sb = s;

	s->s_fs_info = sbi;

	s->s_blocksize = 1024;

	s->s_blocksize_bits = 10;

	s->s_magic = AUTOFS_SUPER_MAGIC;
@@ -338,33 +315,24 @@ int autofs_fill_super(struct super_block *s, void *data, int silent) 
	 * Get the root inode and dentry, but defer checking for errors.

	 */

	ino = autofs_new_ino(sbi);

	if (!ino) {

		ret = -ENOMEM;

		goto fail_free;

	}

	if (!ino)

		goto fail;



	root_inode = autofs_get_inode(s, S_IFDIR | 0755);

	root_inode->i_uid = ctx->uid;

	root_inode->i_gid = ctx->gid;



	root = d_make_root(root_inode);

	if (!root) {

		ret = -ENOMEM;

	if (!root)

		goto fail_ino;

	}



	root->d_fsdata = ino;



	/* Can this call block? */

	if (parse_options(data, root_inode, &pgrp, &pgrp_set, sbi)) {

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

		goto fail_dput;

	}



	if (autofs_validate_protocol(sbi))

		goto fail_dput;



	if (pgrp_set) {

		sbi->oz_pgrp = find_get_pid(pgrp);

	if (ctx->pgrp_set) {

		sbi->oz_pgrp = find_get_pid(ctx->pgrp);

		if (!sbi->oz_pgrp) {

			pr_err("could not find process group %d\n",

				pgrp);

			ret = invalf(fc, "Could not find process group %d",

				     ctx->pgrp);

			goto fail_dput;

		}

	} else {
@@ -393,15 +361,80 @@ int autofs_fill_super(struct super_block *s, void *data, int silent) 
	 */

fail_dput:

	dput(root);

	goto fail_free;

	goto fail;

fail_ino:

	autofs_free_ino(ino);

fail_free:

	kfree(sbi);

	s->s_fs_info = NULL;

fail:

	return ret;

}



/*

 * Validate the parameters and then request a superblock.

 */

static int autofs_get_tree(struct fs_context *fc)

{

	struct autofs_sb_info *sbi = fc->s_fs_info;

	int ret;



	ret = autofs_validate_protocol(fc);

	if (ret)

		return ret;



	if (sbi->pipefd < 0)

		return invalf(fc, "No control pipe specified");



	return get_tree_nodev(fc, autofs_fill_super);

}



static void autofs_free_fc(struct fs_context *fc)

{

	struct autofs_fs_context *ctx = fc->fs_private;

	struct autofs_sb_info *sbi = fc->s_fs_info;



	if (sbi) {

		if (sbi->pipe)

			fput(sbi->pipe);

		kfree(sbi);

	}

	kfree(ctx);

}



static const struct fs_context_operations autofs_context_ops = {

	.free		= autofs_free_fc,

	.parse_param	= autofs_parse_param,

	.get_tree	= autofs_get_tree,

};



/*

 * Set up the filesystem mount context.

 */

int autofs_init_fs_context(struct fs_context *fc)

{

	struct autofs_fs_context *ctx;

	struct autofs_sb_info *sbi;



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

	if (!ctx)

		goto nomem;



	ctx->uid = current_uid();

	ctx->gid = current_gid();



	sbi = autofs_alloc_sbi();

	if (!sbi)

		goto nomem_ctx;



	fc->fs_private = ctx;

	fc->s_fs_info = sbi;

	fc->ops = &autofs_context_ops;

	return 0;



nomem_ctx:

	kfree(ctx);

nomem:

	return -ENOMEM;

}



struct inode *autofs_get_inode(struct super_block *sb, umode_t mode)

{

	struct inode *inode = new_inode(sb);