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: Ian Kent <raven@themaw.net>
Reviewed-by: Bill O'Donnell <bodonnel@redhat.com>
Message-Id: <20230922041215.13675-8-raven@themaw.net>
Signed-off-by: Christian Brauner <brauner@kernel.org>
This commit is contained in:
Ian Kent 2023-09-22 12:12:14 +08:00 committed by Christian Brauner
parent 1f50012d9c
commit e6ec453bd0
3 changed files with 155 additions and 124 deletions

View File

@ -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 *);

View File

@ -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");

View File

@ -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,
@ -125,100 +123,106 @@ 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");
fput(pipe);
errorf(fc, "Invalid/unusable pipe");
if (param->type != fs_value_is_file)
fput(pipe);
return -EBADF;
}
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;
token = match_token(optstr, tokens, args);
switch (token) {
opt = fs_parse(fc, autofs_param_specs, param, &result);
if (opt < 0)
return opt;
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);