[Devel] Re: [PATCH 03/10] Per-mount 'config' object

[Serge E. Hallyn]

Quoting sukadev at us.ibm.com (sukadev at us.ibm.com):
> 
> >From 449652761e1d0c620a01577002ad655adac9a1c5 Mon Sep 17 00:00:00 2001
> From: Sukadev Bhattiprolu <sukadev at us.ibm.com>
> Date: Tue, 9 Sep 2008 10:22:53 -0700
> Subject: [PATCH 03/10] Per-mount 'config' object
> 
> With support for multiple mounts of devpts, the 'config' structure really
> represents per-mount options rather than config parameters. Rename 'config'
> structure to 'pts_mount_opts' and store it in the super-block.
> 
> Signed-off-by: Sukadev Bhattiprolu <sukadev at us.ibm.com>

Acked-by: Serge Hallyn <serue at us.ibm.com>

(except, of course, for wanting the DEVPTS_SB fn to be renamed)

> ---
>  fs/devpts/inode.c |   49 +++++++++++++++++++++++++++++--------------------
>  1 files changed, 29 insertions(+), 20 deletions(-)
> 
> diff --git a/fs/devpts/inode.c b/fs/devpts/inode.c
> index 6e63db7..e91c15c 100644
> --- a/fs/devpts/inode.c
> +++ b/fs/devpts/inode.c
> @@ -34,13 +34,13 @@ static DEFINE_MUTEX(allocated_ptys_lock);
> 
>  static struct vfsmount *devpts_mnt;
> 
> -static struct {
> +struct pts_mount_opts {
>  	int setuid;
>  	int setgid;
>  	uid_t   uid;
>  	gid_t   gid;
>  	umode_t mode;
> -} config = {.mode = DEVPTS_DEFAULT_MODE};
> +};
> 
>  enum {
>  	Opt_uid, Opt_gid, Opt_mode,
> @@ -56,6 +56,7 @@ static match_table_t tokens = {
> 
>  struct pts_fs_info {
>  	struct ida allocated_ptys;
> +	struct pts_mount_opts mount_opts;
>  };
> 
>  static inline struct pts_fs_info *DEVPTS_SB(struct super_block *sb)
> @@ -74,12 +75,14 @@ static inline struct super_block *pts_sb_from_inode(struct inode *inode)
>  static int devpts_remount(struct super_block *sb, int *flags, char *data)
>  {
>  	char *p;
> +	struct pts_fs_info *fsi = DEVPTS_SB(sb);
> +	struct pts_mount_opts *opts = &fsi->mount_opts;
> 
> -	config.setuid  = 0;
> -	config.setgid  = 0;
> -	config.uid     = 0;
> -	config.gid     = 0;
> -	config.mode    = DEVPTS_DEFAULT_MODE;
> +	opts->setuid  = 0;
> +	opts->setgid  = 0;
> +	opts->uid     = 0;
> +	opts->gid     = 0;
> +	opts->mode    = DEVPTS_DEFAULT_MODE;
> 
>  	while ((p = strsep(&data, ",")) != NULL) {
>  		substring_t args[MAX_OPT_ARGS];
> @@ -94,19 +97,19 @@ static int devpts_remount(struct super_block *sb, int *flags, char *data)
>  		case Opt_uid:
>  			if (match_int(&args[0], &option))
>  				return -EINVAL;
> -			config.uid = option;
> -			config.setuid = 1;
> +			opts->uid = option;
> +			opts->setuid = 1;
>  			break;
>  		case Opt_gid:
>  			if (match_int(&args[0], &option))
>  				return -EINVAL;
> -			config.gid = option;
> -			config.setgid = 1;
> +			opts->gid = option;
> +			opts->setgid = 1;
>  			break;
>  		case Opt_mode:
>  			if (match_octal(&args[0], &option))
>  				return -EINVAL;
> -			config.mode = option & S_IALLUGO;
> +			opts->mode = option & S_IALLUGO;
>  			break;
>  		default:
>  			printk(KERN_ERR "devpts: called with bogus options\n");
> @@ -119,11 +122,14 @@ static int devpts_remount(struct super_block *sb, int *flags, char *data)
> 
>  static int devpts_show_options(struct seq_file *seq, struct vfsmount *vfs)
>  {
> -	if (config.setuid)
> -		seq_printf(seq, ",uid=%u", config.uid);
> -	if (config.setgid)
> -		seq_printf(seq, ",gid=%u", config.gid);
> -	seq_printf(seq, ",mode=%03o", config.mode);
> +	struct pts_fs_info *fsi = DEVPTS_SB(vfs->mnt_sb);
> +	struct pts_mount_opts *opts = &fsi->mount_opts;
> +
> +	if (opts->setuid)
> +		seq_printf(seq, ",uid=%u", opts->uid);
> +	if (opts->setgid)
> +		seq_printf(seq, ",gid=%u", opts->gid);
> +	seq_printf(seq, ",mode=%03o", opts->mode);
> 
>  	return 0;
>  }
> @@ -143,6 +149,7 @@ static void *new_pts_fs_info(void)
>  		return NULL;
> 
>  	ida_init(&fsi->allocated_ptys);
> +	fsi->mount_opts.mode = DEVPTS_DEFAULT_MODE;
> 
>  	return fsi;
>  }
> @@ -262,6 +269,8 @@ int devpts_pty_new(struct inode *ptmx_inode, struct tty_struct *tty)
>  	struct super_block *sb = pts_sb_from_inode(ptmx_inode);
>  	struct inode *inode = new_inode(sb);
>  	struct dentry *root = sb->s_root;
> +	struct pts_fs_info *fsi = DEVPTS_SB(sb);
> +	struct pts_mount_opts *opts = &fsi->mount_opts;
>  	char s[12];
> 
>  	/* We're supposed to be given the slave end of a pty */
> @@ -272,10 +281,10 @@ int devpts_pty_new(struct inode *ptmx_inode, struct tty_struct *tty)
>  		return -ENOMEM;
> 
>  	inode->i_ino = number+2;
> -	inode->i_uid = config.setuid ? config.uid : current->fsuid;
> -	inode->i_gid = config.setgid ? config.gid : current->fsgid;
> +	inode->i_uid = opts->setuid ? opts->uid : current->fsuid;
> +	inode->i_gid = opts->setgid ? opts->gid : current->fsgid;
>  	inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
> -	init_special_inode(inode, S_IFCHR|config.mode, device);
> +	init_special_inode(inode, S_IFCHR|opts->mode, device);
>  	inode->i_private = tty;
>  	tty->driver_data = inode;
> 
> -- 
> 1.5.2.5
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