Re: [RFC PATCH 4/5] ubifs: Introduce ACLs mount options

[Li Zetao]

Hi,

On 2024/3/21 14:49, Zhihao Cheng wrote:
> 在 2024/3/20 0:16, Li Zetao 写道:
> > Implement the ability to enable or disable the ACLs feature through
> > mount options. "-o acl" option means enable and "-o noacl" means disable
> > and it is enable by default.
> >
> > Signed-off-by: Li Zetao <lizetao1@xxxxxxxxxx>
> > ---
> >   fs/ubifs/super.c | 40 ++++++++++++++++++++++++++++++++++++++++
> >   fs/ubifs/ubifs.h |  2 ++
> >   2 files changed, 42 insertions(+)
> >
> > diff --git a/fs/ubifs/super.c b/fs/ubifs/super.c
> > index 7f4031a15f4d..ed03bf11e51d 100644
> > --- a/fs/ubifs/super.c
> > +++ b/fs/ubifs/super.c
> > @@ -457,6 +457,13 @@ static int ubifs_show_options(struct seq_file *s, 
> > struct dentry *root)
> >       seq_printf(s, ",assert=%s", ubifs_assert_action_name(c));
> >       seq_printf(s, ",ubi=%d,vol=%d", c->vi.ubi_num, c->vi.vol_id);
> > +#ifdef CONFIG_UBIFS_FS_POSIX_ACL
>
> This config is introduced in pacth 5, we cannot use it in patch 4.
> > +    if (c->mount_opts.acl == 2)
> > +        seq_puts(s, ",acl");
> > +    else if (c->mount_opts.acl == 1)
> > +        seq_puts(s, ",noacl");
> > +#endif
> > +
> >       return 0;
> >   }
> > @@ -967,6 +974,8 @@ static int check_volume_empty(struct ubifs_info *c)
> >    * Opt_assert: set ubifs_assert() action
> >    * Opt_auth_key: The key name used for authentication
> >    * Opt_auth_hash_name: The hash type used for authentication
> > + * Opt_acl: enable posix acl
> > + * Opt_noacl: disable posix acl
> >    * Opt_err: just end of array marker
> >    */
> >   enum {
> > @@ -981,6 +990,8 @@ enum {
> >       Opt_auth_key,
> >       Opt_auth_hash_name,
> >       Opt_ignore,
> > +    Opt_acl,
> > +    Opt_noacl,
> It would be better to update Documentation/filesystems/ubifs.rst to 
> describe new mount options
Ok.
> >       Opt_err,
> >   };
> > @@ -997,6 +1008,8 @@ static const match_table_t tokens = {
> >       {Opt_ignore, "ubi=%s"},
> >       {Opt_ignore, "vol=%s"},
> >       {Opt_assert, "assert=%s"},
> > +    {Opt_acl, "acl"},
> > +    {Opt_noacl, "noacl"},
> >       {Opt_err, NULL},
> >   };
> > @@ -1137,6 +1150,23 @@ static int ubifs_parse_options(struct 
> > ubifs_info *c, char *options,
> >               break;
> >           case Opt_ignore:
> >               break;
> > +#ifdef CONFIG_UBIFS_FS_POSIX_ACL
> > +        case Opt_acl:
> > +            c->mount_opts.acl = 2;
> > +            c->vfs_sb->s_flags |= SB_POSIXACL;
> > +            break;
> > +        case Opt_noacl:
> > +            c->mount_opts.acl = 1;
> > +            c->vfs_sb->s_flags &= ~SB_POSIXACL;
> > +            break;
> > +#else
> > +        case Opt_acl:
> > +            ubifs_err(c, "acl options not supported");
> > +            return -EINVAL;
> > +        case Opt_noacl:
> > +            ubifs_err(c, "noacl options not supported");
> > +            return -EINVAL;
> > +#endif
> >           default:
> >           {
> >               unsigned long flag;
> > @@ -2011,12 +2041,17 @@ static int ubifs_remount_fs(struct super_block 
> > *sb, int *flags, char *data)
> >       sync_filesystem(sb);
> >       dbg_gen("old flags %#lx, new flags %#x", sb->s_flags, *flags);
> > +    c->mount_opts.acl = 0;
> >       err = ubifs_parse_options(c, data, 1);
>
> 1. mount -onoacl /dev/ubi0_0 /mnt # After that, mount will show 'noacl' 
> option
> 2. mount -oremount,xxx /dev/ubi0_0 /mnt
> If 'xxx' has nothing to do with acl, c->mount_opts.acl is set as '0'. 
> Then superblock flag is assigned with 'SB_POSIXACL' and mount will not 
> display 'nocal'. Will it make user confused?
I have tested this use case and it works fine. This is because the mount 
options will be re-parsed during remount, just like the last mount. But 
this is indeed redundant. I adjusted it to make it more reasonable.
> >       if (err) {
> >           ubifs_err(c, "invalid or unknown remount parameter");
> >           return err;
> >       }
> > +#ifdef CONFIG_UBIFS_FS_POSIX_ACL
> > +    if (!c->mount_opts.acl)
> > +        c->vfs_sb->s_flags |= SB_POSIXACL;
> > +#endif
> >       if (c->ro_mount && !(*flags & SB_RDONLY)) {
> >           if (c->ro_error) {
> >               ubifs_msg(c, "cannot re-mount R/W due to prior errors");
> > @@ -2197,6 +2232,11 @@ static int ubifs_fill_super(struct super_block 
> > *sb, void *data, int silent)
> >       if (err)
> >           goto out_close;
> > +#ifdef CONFIG_UBIFS_FS_POSIX_ACL
> > +    if (!c->mount_opts.acl)
> > +        c->vfs_sb->s_flags |= SB_POSIXACL;
> > +#endif
> > +
> >       /*
> >        * UBIFS provides 'backing_dev_info' in order to disable 
> > read-ahead. For
> >        * UBIFS, I/O is not deferred, it is done immediately in 
> > read_folio,
> > diff --git a/fs/ubifs/ubifs.h b/fs/ubifs/ubifs.h
> > index b0d3b076290d..4a6078cbb2f5 100644
> > --- a/fs/ubifs/ubifs.h
> > +++ b/fs/ubifs/ubifs.h
> > @@ -956,6 +956,7 @@ struct ubifs_orphan {
> >    *                  specified in @compr_type)
> >    * @compr_type: compressor type to override the superblock 
> > compressor with
> >    *              (%UBIFS_COMPR_NONE, etc)
> > + * @acl: enable/disable posix acl (%0 default, %1 disable, %2 enable)
> >    */
> >   struct ubifs_mount_opts {
> >       unsigned int unmount_mode:2;
> > @@ -963,6 +964,7 @@ struct ubifs_mount_opts {
> >       unsigned int chk_data_crc:2;
> >       unsigned int override_compr:1;
> >       unsigned int compr_type:2;
> > +    unsigned int acl:2;
> >   };
> >   /**