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Merge tag 'vfs-6.10.mount' of git:https://git.kernel.org/pub/scm/linux/kern…
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…el/git/vfs/vfs

Pull vfs mount API conversions from Christian Brauner:
 "This converts qnx6, minix, debugfs, tracefs, freevxfs, and openpromfs
  to the new mount api, further reducing the number of filesystems
  relying on the legacy mount api"

* tag 'vfs-6.10.mount' of git:https://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
  minix: convert minix to use the new mount api
  vfs: Convert tracefs to use the new mount API
  vfs: Convert debugfs to use the new mount API
  openpromfs: finish conversion to the new mount API
  freevxfs: Convert freevxfs to the new mount API.
  qnx6: convert qnx6 to use the new mount api
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@torvalds
torvalds committed May 13, 2024
2 parents 1b0aabc + 7cd7bfe commit 103fb21
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Showing 6 changed files with 330 additions and 312 deletions.
198 changes: 93 additions & 105 deletions fs/debugfs/inode.c
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Original file line number Diff line number Diff line change
Expand Up @@ -14,7 +14,8 @@

#include <linux/module.h>
#include <linux/fs.h>
#include <linux/mount.h>
#include <linux/fs_context.h>
#include <linux/fs_parser.h>
#include <linux/pagemap.h>
#include <linux/init.h>
#include <linux/kobject.h>
Expand All @@ -23,7 +24,6 @@
#include <linux/fsnotify.h>
#include <linux/string.h>
#include <linux/seq_file.h>
#include <linux/parser.h>
#include <linux/magic.h>
#include <linux/slab.h>
#include <linux/security.h>
Expand Down Expand Up @@ -77,7 +77,7 @@ static struct inode *debugfs_get_inode(struct super_block *sb)
return inode;
}

struct debugfs_mount_opts {
struct debugfs_fs_info {
kuid_t uid;
kgid_t gid;
umode_t mode;
Expand All @@ -89,92 +89,74 @@ enum {
Opt_uid,
Opt_gid,
Opt_mode,
Opt_err
};

static const match_table_t tokens = {
{Opt_uid, "uid=%u"},
{Opt_gid, "gid=%u"},
{Opt_mode, "mode=%o"},
{Opt_err, NULL}
static const struct fs_parameter_spec debugfs_param_specs[] = {
fsparam_u32 ("gid", Opt_gid),
fsparam_u32oct ("mode", Opt_mode),
fsparam_u32 ("uid", Opt_uid),
{}
};

struct debugfs_fs_info {
struct debugfs_mount_opts mount_opts;
};

static int debugfs_parse_options(char *data, struct debugfs_mount_opts *opts)
static int debugfs_parse_param(struct fs_context *fc, struct fs_parameter *param)
{
substring_t args[MAX_OPT_ARGS];
int option;
int token;
struct debugfs_fs_info *opts = fc->s_fs_info;
struct fs_parse_result result;
kuid_t uid;
kgid_t gid;
char *p;

opts->opts = 0;
opts->mode = DEBUGFS_DEFAULT_MODE;

while ((p = strsep(&data, ",")) != NULL) {
if (!*p)
continue;

token = match_token(p, tokens, args);
switch (token) {
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;
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;
break;
case Opt_mode:
if (match_octal(&args[0], &option))
return -EINVAL;
opts->mode = option & S_IALLUGO;
break;
/*
* We might like to report bad mount options here;
* but traditionally debugfs has ignored all mount options
*/
}

opts->opts |= BIT(token);
int opt;

opt = fs_parse(fc, debugfs_param_specs, param, &result);
if (opt < 0)
return opt;

switch (opt) {
case Opt_uid:
uid = make_kuid(current_user_ns(), result.uint_32);
if (!uid_valid(uid))
return invalf(fc, "Unknown uid");
opts->uid = uid;
break;
case Opt_gid:
gid = make_kgid(current_user_ns(), result.uint_32);
if (!gid_valid(gid))
return invalf(fc, "Unknown gid");
opts->gid = gid;
break;
case Opt_mode:
opts->mode = result.uint_32 & S_IALLUGO;
break;
/*
* We might like to report bad mount options here;
* but traditionally debugfs has ignored all mount options
*/
}

opts->opts |= BIT(opt);

return 0;
}

static void _debugfs_apply_options(struct super_block *sb, bool remount)
{
struct debugfs_fs_info *fsi = sb->s_fs_info;
struct inode *inode = d_inode(sb->s_root);
struct debugfs_mount_opts *opts = &fsi->mount_opts;

/*
* On remount, only reset mode/uid/gid if they were provided as mount
* options.
*/

if (!remount || opts->opts & BIT(Opt_mode)) {
if (!remount || fsi->opts & BIT(Opt_mode)) {
inode->i_mode &= ~S_IALLUGO;
inode->i_mode |= opts->mode;
inode->i_mode |= fsi->mode;
}

if (!remount || opts->opts & BIT(Opt_uid))
inode->i_uid = opts->uid;
if (!remount || fsi->opts & BIT(Opt_uid))
inode->i_uid = fsi->uid;

if (!remount || opts->opts & BIT(Opt_gid))
inode->i_gid = opts->gid;
if (!remount || fsi->opts & BIT(Opt_gid))
inode->i_gid = fsi->gid;
}

static void debugfs_apply_options(struct super_block *sb)
Expand All @@ -187,35 +169,33 @@ static void debugfs_apply_options_remount(struct super_block *sb)
_debugfs_apply_options(sb, true);
}

static int debugfs_remount(struct super_block *sb, int *flags, char *data)
static int debugfs_reconfigure(struct fs_context *fc)
{
int err;
struct debugfs_fs_info *fsi = sb->s_fs_info;
struct super_block *sb = fc->root->d_sb;
struct debugfs_fs_info *sb_opts = sb->s_fs_info;
struct debugfs_fs_info *new_opts = fc->s_fs_info;

sync_filesystem(sb);
err = debugfs_parse_options(data, &fsi->mount_opts);
if (err)
goto fail;

/* structure copy of new mount options to sb */
*sb_opts = *new_opts;
debugfs_apply_options_remount(sb);

fail:
return err;
return 0;
}

static int debugfs_show_options(struct seq_file *m, struct dentry *root)
{
struct debugfs_fs_info *fsi = root->d_sb->s_fs_info;
struct debugfs_mount_opts *opts = &fsi->mount_opts;

if (!uid_eq(opts->uid, GLOBAL_ROOT_UID))
if (!uid_eq(fsi->uid, GLOBAL_ROOT_UID))
seq_printf(m, ",uid=%u",
from_kuid_munged(&init_user_ns, opts->uid));
if (!gid_eq(opts->gid, GLOBAL_ROOT_GID))
from_kuid_munged(&init_user_ns, fsi->uid));
if (!gid_eq(fsi->gid, GLOBAL_ROOT_GID))
seq_printf(m, ",gid=%u",
from_kgid_munged(&init_user_ns, opts->gid));
if (opts->mode != DEBUGFS_DEFAULT_MODE)
seq_printf(m, ",mode=%o", opts->mode);
from_kgid_munged(&init_user_ns, fsi->gid));
if (fsi->mode != DEBUGFS_DEFAULT_MODE)
seq_printf(m, ",mode=%o", fsi->mode);

return 0;
}
Expand All @@ -229,7 +209,6 @@ static void debugfs_free_inode(struct inode *inode)

static const struct super_operations debugfs_super_operations = {
.statfs = simple_statfs,
.remount_fs = debugfs_remount,
.show_options = debugfs_show_options,
.free_inode = debugfs_free_inode,
};
Expand Down Expand Up @@ -263,54 +242,63 @@ static const struct dentry_operations debugfs_dops = {
.d_automount = debugfs_automount,
};

static int debug_fill_super(struct super_block *sb, void *data, int silent)
static int debugfs_fill_super(struct super_block *sb, struct fs_context *fc)
{
static const struct tree_descr debug_files[] = {{""}};
struct debugfs_fs_info *fsi;
int err;

fsi = kzalloc(sizeof(struct debugfs_fs_info), GFP_KERNEL);
sb->s_fs_info = fsi;
if (!fsi) {
err = -ENOMEM;
goto fail;
}

err = debugfs_parse_options(data, &fsi->mount_opts);
err = simple_fill_super(sb, DEBUGFS_MAGIC, debug_files);
if (err)
goto fail;

err = simple_fill_super(sb, DEBUGFS_MAGIC, debug_files);
if (err)
goto fail;
return err;

sb->s_op = &debugfs_super_operations;
sb->s_d_op = &debugfs_dops;

debugfs_apply_options(sb);

return 0;

fail:
kfree(fsi);
sb->s_fs_info = NULL;
return err;
}

static struct dentry *debug_mount(struct file_system_type *fs_type,
int flags, const char *dev_name,
void *data)
static int debugfs_get_tree(struct fs_context *fc)
{
if (!(debugfs_allow & DEBUGFS_ALLOW_API))
return ERR_PTR(-EPERM);
return -EPERM;

return get_tree_single(fc, debugfs_fill_super);
}

static void debugfs_free_fc(struct fs_context *fc)
{
kfree(fc->s_fs_info);
}

return mount_single(fs_type, flags, data, debug_fill_super);
static const struct fs_context_operations debugfs_context_ops = {
.free = debugfs_free_fc,
.parse_param = debugfs_parse_param,
.get_tree = debugfs_get_tree,
.reconfigure = debugfs_reconfigure,
};

static int debugfs_init_fs_context(struct fs_context *fc)
{
struct debugfs_fs_info *fsi;

fsi = kzalloc(sizeof(struct debugfs_fs_info), GFP_KERNEL);
if (!fsi)
return -ENOMEM;

fsi->mode = DEBUGFS_DEFAULT_MODE;

fc->s_fs_info = fsi;
fc->ops = &debugfs_context_ops;
return 0;
}

static struct file_system_type debug_fs_type = {
.owner = THIS_MODULE,
.name = "debugfs",
.mount = debug_mount,
.init_fs_context = debugfs_init_fs_context,
.parameters = debugfs_param_specs,
.kill_sb = kill_litter_super,
};
MODULE_ALIAS_FS("debugfs");
Expand Down
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