Re: [PATCH v2 3/6] fs/ntfs3: Use new api for mounting

Christian Brauner
2021-08-24T11:32:23Z

On Thu, Aug 19, 2021 at 03:26:30AM +0300, Kari Argillander wrote:
> We have now new mount api as described in Documentation/filesystems. We
> should use it as it gives us some benefits which are desribed here
> lore.kernel.org/linux-fsdevel/159646178122.1784947.11705396571718464082.stgit@warthog.procyon.org.uk/
>
> Nls loading is changed a to load with string. This did make code also
> little cleaner.
>
> Also try to use fsparam_flag_no as much as possible. This is just nice
> little touch and is not mandatory but it should not make any harm. It
> is just convenient that we can use example acl/noacl mount options.
>
> Signed-off-by: Kari Argillander <kari.argillander@gmail.com>
> ---

Looks mostly sane to me. Thanks!
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>

> fs/ntfs3/ntfs_fs.h | 1 +
> fs/ntfs3/super.c | 392 +++++++++++++++++++++++----------------------
> 2 files changed, 199 insertions(+), 194 deletions(-)
>
> diff --git a/fs/ntfs3/ntfs_fs.h b/fs/ntfs3/ntfs_fs.h
> index 0c3ac89c3115..1f07dd17c6c7 100644
> --- a/fs/ntfs3/ntfs_fs.h
> +++ b/fs/ntfs3/ntfs_fs.h
> @@ -50,6 +50,7 @@
>
> struct ntfs_mount_options {
> struct nls_table *nls;
> + char *nls_name;
>
> kuid_t fs_uid;
> kgid_t fs_gid;
> diff --git a/fs/ntfs3/super.c b/fs/ntfs3/super.c
> index 702da1437cfd..39936a4ce831 100644
> --- a/fs/ntfs3/super.c
> +++ b/fs/ntfs3/super.c
> @@ -28,10 +28,11 @@
> #include <linux/buffer_head.h>
> #include <linux/exportfs.h>
> #include <linux/fs.h>
> +#include <linux/fs_context.h>
> +#include <linux/fs_parser.h>
> #include <linux/iversion.h>
> #include <linux/module.h>
> #include <linux/nls.h>
> -#include <linux/parser.h>
> #include <linux/seq_file.h>
> #include <linux/statfs.h>
>
> @@ -197,8 +198,32 @@ void *ntfs_put_shared(void *ptr)
> return ret;
> }
>
> +/*
> + * Load nls table or if @nls is utf8 then return NULL because
> + * nls=utf8 is totally broken.
> + */
> +static struct nls_table *ntfs_load_nls(char *nls)
> +{
> + struct nls_table *ret;
> +
> + if (!nls)
> + nls = CONFIG_NLS_DEFAULT;
> +
> + if (strcmp(nls, "utf8"))
> + return NULL;
> + if (strcmp(nls, CONFIG_NLS_DEFAULT))
> + return load_nls_default();
> +
> + ret = load_nls(nls);
> + if (!ret)
> + return ERR_PTR(-EINVAL);
> +
> + return ret;
> +}
> +
> static inline void clear_mount_options(struct ntfs_mount_options *options)
> {
> + kfree(options->nls_name);
> unload_nls(options->nls);
> }
>
> @@ -221,202 +246,150 @@ enum Opt {
> Opt_err,
> };
>
> -static const match_table_t ntfs_tokens = {
> - { Opt_uid, "uid=%u" },
> - { Opt_gid, "gid=%u" },
> - { Opt_umask, "umask=%o" },
> - { Opt_dmask, "dmask=%o" },
> - { Opt_fmask, "fmask=%o" },
> - { Opt_immutable, "sys_immutable" },
> - { Opt_discard, "discard" },
> - { Opt_force, "force" },
> - { Opt_sparse, "sparse" },
> - { Opt_nohidden, "nohidden" },
> - { Opt_acl, "acl" },
> - { Opt_showmeta, "showmeta" },
> - { Opt_nls, "nls=%s" },
> - { Opt_prealloc, "prealloc" },
> - { Opt_no_acs_rules, "no_acs_rules" },
> - { Opt_err, NULL },
> +static const struct fs_parameter_spec ntfs_fs_parameters[] = {
> + fsparam_u32("uid", Opt_uid),
> + fsparam_u32("gid", Opt_gid),
> + fsparam_u32oct("umask", Opt_umask),
> + fsparam_u32oct("dmask", Opt_dmask),
> + fsparam_u32oct("fmask", Opt_fmask),
> + fsparam_flag_no("sys_immutable", Opt_immutable),
> + fsparam_flag_no("discard", Opt_discard),
> + fsparam_flag_no("force", Opt_force),
> + fsparam_flag_no("sparse", Opt_sparse),
> + fsparam_flag("nohidden", Opt_nohidden),
> + fsparam_flag_no("acl", Opt_acl),
> + fsparam_flag_no("showmeta", Opt_showmeta),
> + fsparam_string("nls", Opt_nls),
> + fsparam_flag_no("prealloc", Opt_prealloc),
> + fsparam_flag("no_acs_rules", Opt_no_acs_rules),
> + {}
> };
>
> -static noinline int ntfs_parse_options(struct super_block *sb, char *options,
> - int silent,
> - struct ntfs_mount_options *opts)
> +static int ntfs_fs_parse_param(struct fs_context *fc,
> + struct fs_parameter *param)
> {
> - char *p;
> - substring_t args[MAX_OPT_ARGS];
> - int option;
> - char nls_name[30];
> - struct nls_table *nls;
> -
> - opts->fs_uid = current_uid();
> - opts->fs_gid = current_gid();
> - opts->fs_fmask_inv = opts->fs_dmask_inv = ~current_umask();
> - nls_name[0] = 0;
> -
> - if (!options)
> - goto out;
> -
> - while ((p = strsep(&options, ","))) {
> - int token;
> + struct ntfs_sb_info *sbi = fc->s_fs_info;
> + struct ntfs_mount_options *opts = &sbi->options;
> + struct fs_parse_result result;
> + int opt;
>
> - if (!*p)
> - continue;
> + opt = fs_parse(fc, ntfs_fs_parameters, param, &result);
> + if (opt < 0)
> + return opt;
>
> - token = match_token(p, ntfs_tokens, args);
> - switch (token) {
> - case Opt_immutable:
> - opts->sys_immutable = 1;
> - break;
> - case Opt_uid:
> - if (match_int(&args[0], &option))
> - return -EINVAL;
> - opts->fs_uid = make_kuid(current_user_ns(), option);
> - if (!uid_valid(opts->fs_uid))
> - return -EINVAL;
> - opts->uid = 1;
> - break;
> - case Opt_gid:
> - if (match_int(&args[0], &option))
> - return -EINVAL;
> - opts->fs_gid = make_kgid(current_user_ns(), option);
> - if (!gid_valid(opts->fs_gid))
> - return -EINVAL;
> - opts->gid = 1;
> - break;
> - case Opt_umask:
> - if (match_octal(&args[0], &option))
> - return -EINVAL;
> - opts->fs_fmask_inv = opts->fs_dmask_inv = ~option;
> - opts->fmask = opts->dmask = 1;
> - break;
> - case Opt_dmask:
> - if (match_octal(&args[0], &option))
> - return -EINVAL;
> - opts->fs_dmask_inv = ~option;
> - opts->dmask = 1;
> - break;
> - case Opt_fmask:
> - if (match_octal(&args[0], &option))
> - return -EINVAL;
> - opts->fs_fmask_inv = ~option;
> - opts->fmask = 1;
> - break;
> - case Opt_discard:
> - opts->discard = 1;
> - break;
> - case Opt_force:
> - opts->force = 1;
> - break;
> - case Opt_sparse:
> - opts->sparse = 1;
> - break;
> - case Opt_nohidden:
> - opts->nohidden = 1;
> - break;
> - case Opt_acl:
> + switch (opt) {
> + case Opt_uid:
> + opts->fs_uid = make_kuid(current_user_ns(), result.uint_32);
> + if (!uid_valid(opts->fs_uid))
> + return -EINVAL;
> + opts->uid = 1;

If you're only using opts->uid to check whether ->fs_*id is set then you
can probably simplify this. You're expressing the expectation that if
->fs_*id is set that it must be a valid *id. So you could initialize
->fs_*id to INVALID_*ID and then instead of having to check "if
(opts->uid)" in later code you can directly check "if (valid_uid(opts->fs_uid))".
Just a thought.

> + break;
> + case Opt_gid:
> + opts->fs_gid = make_kgid(current_user_ns(), result.uint_32);
> + if (!gid_valid(opts->fs_gid))
> + return -EINVAL;
> + opts->gid = 1;
> + break;
> + case Opt_umask:
> + opts->fs_fmask_inv = ~result.uint_32;
> + opts->fs_dmask_inv = ~result.uint_32;
> + opts->fmask = 1;
> + opts->dmask = 1;
> + break;
> + case Opt_dmask:
> + opts->fs_dmask_inv = ~result.uint_32;
> + opts->dmask = 1;
> + break;
> + case Opt_fmask:
> + opts->fs_fmask_inv = ~result.uint_32;
> + opts->fmask = 1;
> + break;
> + case Opt_immutable:
> + opts->sys_immutable = result.negated ? 0 : 1;
> + break;
> + case Opt_discard:
> + opts->discard = result.negated ? 0 : 1;
> + break;
> + case Opt_force:
> + opts->force = result.negated ? 0 : 1;
> + break;
> + case Opt_sparse:
> + opts->sparse = result.negated ? 0 : 1;
> + break;
> + case Opt_nohidden:
> + opts->nohidden = 1;
> + break;
> + case Opt_acl:
> + if (!result.negated)
> #ifdef CONFIG_NTFS3_FS_POSIX_ACL
> - sb->s_flags |= SB_POSIXACL;
> - break;
> + fc->sb_flags |= SB_POSIXACL;
> #else
> - ntfs_err(sb, "support for ACL not compiled in!");
> - return -EINVAL;
> + return invalf(fc, "ntfs3: Support for ACL not compiled in!");
> #endif
> - case Opt_showmeta:
> - opts->showmeta = 1;
> - break;
> - case Opt_nls:
> - match_strlcpy(nls_name, &args[0], sizeof(nls_name));
> - break;
> - case Opt_prealloc:
> - opts->prealloc = 1;
> - break;
> - case Opt_no_acs_rules:
> - opts->no_acs_rules = 1;
> - break;
> - default:
> - if (!silent)
> - ntfs_err(
> - sb,
> - "Unrecognized mount option \"%s\" or missing value",
> - p);
> - //return -EINVAL;
> - }
> + else
> + fc->sb_flags &= ~SB_POSIXACL;
> + break;
> + case Opt_showmeta:
> + opts->showmeta = result.negated ? 0 : 1;
> + break;
> + case Opt_nls:
> + opts->nls_name = param->string;
> + param->string = NULL;
> + break;
> + case Opt_prealloc:
> + opts->prealloc = result.negated ? 0 : 1;
> + break;
> + case Opt_no_acs_rules:
> + opts->no_acs_rules = 1;
> + break;
> + default:
> + /* Should not be here unless we forget add case. */
> + return -EINVAL;
> }
> -
> -out:
> - if (!strcmp(nls_name[0] ? nls_name : CONFIG_NLS_DEFAULT, "utf8")) {
> - /* For UTF-8 use utf16s_to_utf8s/utf8s_to_utf16s instead of nls */
> - nls = NULL;
> - } else if (nls_name[0]) {
> - nls = load_nls(nls_name);
> - if (!nls) {
> - ntfs_err(sb, "failed to load \"%s\"", nls_name);
> - return -EINVAL;
> - }
> - } else {
> - nls = load_nls_default();
> - if (!nls) {
> - ntfs_err(sb, "failed to load default nls");
> - return -EINVAL;
> - }
> - }
> - opts->nls = nls;
> -
> return 0;
> }
>
> -static int ntfs_remount(struct super_block *sb, int *flags, char *data)
> +static int ntfs_fs_reconfigure(struct fs_context *fc)
> {
> - int err, ro_rw;
> + struct super_block *sb = fc->root->d_sb;
> struct ntfs_sb_info *sbi = sb->s_fs_info;
> - struct ntfs_mount_options old_opts;
> - char *orig_data = kstrdup(data, GFP_KERNEL);
> + struct ntfs_mount_options *new_opts = fc->s_fs_info;
> + int ro_rw;
>
> - if (data && !orig_data)
> - return -ENOMEM;
> -
> - /* Store original options */
> - memcpy(&old_opts, &sbi->options, sizeof(old_opts));
> - clear_mount_options(&sbi->options);
> - memset(&sbi->options, 0, sizeof(sbi->options));
> -
> - err = ntfs_parse_options(sb, data, 0, &sbi->options);
> - if (err)
> - goto restore_opts;
> -
> - ro_rw = sb_rdonly(sb) && !(*flags & SB_RDONLY);
> + ro_rw = sb_rdonly(sb) && !(fc->sb_flags & SB_RDONLY);
> if (ro_rw && (sbi->flags & NTFS_FLAGS_NEED_REPLAY)) {
> - ntfs_warn(
> - sb,
> - "Couldn't remount rw because journal is not replayed. Please umount/remount instead\n");
> - err = -EINVAL;
> - goto restore_opts;
> + errorf(fc, "ntfs3: Couldn't remount rw because journal is not replayed. Please umount/remount instead\n");
> + goto clear_new_fc;
> }
>
> sync_filesystem(sb);
>
> if (ro_rw && (sbi->volume.flags & VOLUME_FLAG_DIRTY) &&
> - !sbi->options.force) {
> - ntfs_warn(sb, "volume is dirty and \"force\" flag is not set!");
> - err = -EINVAL;
> - goto restore_opts;
> + !new_opts->force) {
> + errorf(fc, "ntfs3: Volume is dirty and \"force\" flag is not set!");
> + goto clear_new_fc;
> }
>
> - clear_mount_options(&old_opts);
> + /*
> + * TODO: We should probably check some mount options does
> + * they all work after remount. Example can we really change
> + * nls. Remove this comment when all testing is done or
> + * even better xfstest is made for it.
> + */
>
> - ntfs_info(sb, "re-mounted. Opts: %s", orig_data);
> - err = 0;
> - goto out;
> + new_opts->nls = ntfs_load_nls(new_opts->nls_name);
> + if (IS_ERR(new_opts->nls)) {
> + errorf(fc, "ntfs3: Cannot load nls %s", new_opts->nls_name);
> + goto clear_new_fc;
> + }
>
> -restore_opts:
> clear_mount_options(&sbi->options);
> - memcpy(&sbi->options, &old_opts, sizeof(old_opts));
> + sbi->options = *new_opts;
> + return 0;
>
> -out:
> - kfree(orig_data);
> - return err;
> +clear_new_fc:
> + clear_mount_options(new_opts);
> + return -EINVAL;
> }
>
> static struct kmem_cache *ntfs_inode_cachep;
> @@ -545,10 +518,8 @@ static int ntfs_show_options(struct seq_file *m, struct dentry *root)
> seq_printf(m, ",fmask=%04o", ~opts->fs_fmask_inv);
> if (opts->dmask)
> seq_printf(m, ",dmask=%04o", ~opts->fs_dmask_inv);
> - if (opts->nls)
> - seq_printf(m, ",nls=%s", opts->nls->charset);
> - else
> - seq_puts(m, ",nls=utf8");
> + if (opts->nls_name)
> + seq_printf(m, ",nls=%s", opts->nls_name);
> if (opts->sys_immutable)
> seq_puts(m, ",sys_immutable");
> if (opts->discard)
> @@ -619,7 +590,6 @@ static const struct super_operations ntfs_sops = {
> .statfs = ntfs_statfs,
> .show_options = ntfs_show_options,
> .sync_fs = ntfs_sync_fs,
> - .remount_fs = ntfs_remount,
> .write_inode = ntfs3_write_inode,
> };
>
> @@ -883,10 +853,10 @@ static int ntfs_init_from_boot(struct super_block *sb, u32 sector_size,
> }
>
> /* try to mount*/
> -static int ntfs_fill_super(struct super_block *sb, void *data, int silent)
> +static int ntfs_fill_super(struct super_block *sb, struct fs_context *fc)
> {
> int err;
> - struct ntfs_sb_info *sbi;
> + struct ntfs_sb_info *sbi = sb->s_fs_info;
> struct block_device *bdev = sb->s_bdev;
> struct inode *bd_inode = bdev->bd_inode;
> struct request_queue *rq = bdev_get_queue(bdev);
> @@ -905,11 +875,6 @@ static int ntfs_fill_super(struct super_block *sb, void *data, int silent)
>
> ref.high = 0;
>
> - sbi = ntfs_zalloc(sizeof(struct ntfs_sb_info));
> - if (!sbi)
> - return -ENOMEM;
> -
> - sb->s_fs_info = sbi;
> sbi->sb = sb;
> sb->s_flags |= SB_NODIRATIME;
> sb->s_magic = 0x7366746e; // "ntfs"
> @@ -921,10 +886,6 @@ static int ntfs_fill_super(struct super_block *sb, void *data, int silent)
> ratelimit_state_init(&sbi->msg_ratelimit, DEFAULT_RATELIMIT_INTERVAL,
> DEFAULT_RATELIMIT_BURST);
>
> - err = ntfs_parse_options(sb, data, silent, &sbi->options);
> - if (err)
> - goto out;
> -
> if (!rq || !blk_queue_discard(rq) || !rq->limits.discard_granularity) {
> ;

Sidenote, why is this lonely semicolon here? Maybe you can rewrite this
so you don't need this branch at all.

> } else {
> @@ -933,6 +894,14 @@ static int ntfs_fill_super(struct super_block *sb, void *data, int silent)
> ~(u64)(sbi->discard_granularity - 1);
> }
>
> + sbi->options.nls = ntfs_load_nls(sbi->options.nls_name);
> + if (IS_ERR(sbi->options.nls)) {
> + ntfs_err(sb, "ntfs3: Cannot load nls %s",
> + sbi->options.nls_name);
> + err = PTR_ERR(sbi->options.nls);
> + goto out;
> + }
> +
> sb_set_blocksize(sb, PAGE_SIZE);
>
> /* parse boot */
> @@ -1400,19 +1369,54 @@ int ntfs_discard(struct ntfs_sb_info *sbi, CLST lcn, CLST len)
> return err;
> }
>
> -static struct dentry *ntfs_mount(struct file_system_type *fs_type, int flags,
> - const char *dev_name, void *data)
> +static int ntfs_fs_get_tree(struct fs_context *fc)
> +{
> + return get_tree_bdev(fc, ntfs_fill_super);
> +}
> +
> +static void ntfs_fs_free(struct fs_context *fc)
> +{
> + struct ntfs_sb_info *sbi = fc->s_fs_info;
> +
> + if (sbi)
> + put_ntfs(sbi);
> +}
> +
> +static const struct fs_context_operations ntfs_context_ops = {
> + .parse_param = ntfs_fs_parse_param,
> + .get_tree = ntfs_fs_get_tree,
> + .reconfigure = ntfs_fs_reconfigure,
> + .free = ntfs_fs_free,
> +};
> +
> +static int ntfs_init_fs_context(struct fs_context *fc)
> {
> - return mount_bdev(fs_type, flags, dev_name, data, ntfs_fill_super);
> + struct ntfs_sb_info *sbi;
> +
> + sbi = ntfs_zalloc(sizeof(struct ntfs_sb_info));
> + if (!sbi)
> + return -ENOMEM;
> +
> + /* Default options */
> + sbi->options.fs_uid = current_uid();
> + sbi->options.fs_gid = current_gid();
> + sbi->options.fs_fmask_inv = ~current_umask();
> + sbi->options.fs_dmask_inv = ~current_umask();
> +
> + fc->s_fs_info = sbi;
> + fc->ops = &ntfs_context_ops;
> +
> + return 0;
> }
>
> // clang-format off
> static struct file_system_type ntfs_fs_type = {
> - .owner = THIS_MODULE,
> - .name = "ntfs3",
> - .mount = ntfs_mount,
> - .kill_sb = kill_block_super,
> - .fs_flags = FS_REQUIRES_DEV | FS_ALLOW_IDMAP,
> + .owner = THIS_MODULE,
> + .name = "ntfs3",
> + .init_fs_context = ntfs_init_fs_context,
> + .parameters = ntfs_fs_parameters,
> + .kill_sb = kill_block_super,
> + .fs_flags = FS_REQUIRES_DEV | FS_ALLOW_IDMAP,
> };
> // clang-format on
>
> --
> 2.25.1
>