Commit 1bd79035 authored by Sukadev Bhattiprolu's avatar Sukadev Bhattiprolu Committed by Al Viro
Browse files

Merge code for single and multiple-instance mounts 



new_pts_mount() (including the get_sb_nodev()), shares a lot of code
with init_pts_mount(). The only difference between them is the 'test-super'
function passed into sget().

Move all common code into devpts_get_sb() and remove the new_pts_mount() and
init_pts_mount() functions,

Changelog[v3]:
	[Serge Hallyn]: Remove unnecessary printk()s
Changelog[v2]:
	(Christoph Hellwig): Merge code in 'do_pts_mount()' into devpts_get_sb()

Signed-off-by: default avatarSukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Acked-by: default avatarSerge Hallyn <serue@us.ibm.com>
Tested-by: default avatarSerge Hallyn <serue@us.ibm.com>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 289f00e2

fs/devpts/inode.c

+40 −73
Original line number Diff line number Diff line
@@ -322,85 +322,38 @@ static int compare_init_pts_sb(struct super_block *s, void *p) 
}



/*

 * Mount a new (private) instance of devpts.  PTYs created in this

 * instance are independent of the PTYs in other devpts instances.

 */

static int new_pts_mount(struct file_system_type *fs_type, int flags,

		void *data, struct pts_mount_opts *opts, struct vfsmount *mnt)

{

	int err;

	struct pts_fs_info *fsi;



	err = get_sb_nodev(fs_type, flags, data, devpts_fill_super, mnt);

	if (err)

		return err;



	fsi = DEVPTS_SB(mnt->mnt_sb);

	memcpy(&fsi->mount_opts, opts, sizeof(opts));



	return 0;

}



/*

 * init_pts_mount()

 * devpts_get_sb()

 *

 *     Mount or remount the initial kernel mount of devpts. This type of

 *     mount maintains the legacy, single-instance semantics, while the

 *     kernel still allows multiple-instances.

 *     If the '-o newinstance' mount option was specified, mount a new

 *     (private) instance of devpts.  PTYs created in this instance are

 *     independent of the PTYs in other devpts instances.

 *

 *     This interface is needed to support multiple namespace semantics in

 *     devpts while preserving backward compatibility of the current 'single-

 *     namespace' semantics. i.e all mounts of devpts without the 'newinstance'

 *     mount option should bind to the initial kernel mount, like

 *     get_sb_single().

 *     If the '-o newinstance' option was not specified, mount/remount the

 *     initial kernel mount of devpts.  This type of mount gives the

 *     legacy, single-instance semantics.

 *

 *     Mounts with 'newinstance' option create a new private namespace.

 *     The 'newinstance' option is needed to support multiple namespace

 *     semantics in devpts while preserving backward compatibility of the

 *     current 'single-namespace' semantics. i.e all mounts of devpts

 *     without the 'newinstance' mount option should bind to the initial

 *     kernel mount, like get_sb_single().

 *

 *     But for single-mount semantics, devpts cannot use get_sb_single(),

 *     Mounts with 'newinstance' option create a new, private namespace.

 *

 *     NOTE:

 *

 *     For single-mount semantics, devpts cannot use get_sb_single(),

 *     because get_sb_single()/sget() find and use the super-block from

 *     the most recent mount of devpts. But that recent mount may be a

 *     'newinstance' mount and get_sb_single() would pick the newinstance

 *     super-block instead of the initial super-block.

 *

 *     This interface is identical to get_sb_single() except that it

 *     consistently selects the 'single-namespace' superblock even in the

 *     presence of the private namespace (i.e 'newinstance') super-blocks.

 */

static int init_pts_mount(struct file_system_type *fs_type, int flags,

		void *data, struct pts_mount_opts *opts, struct vfsmount *mnt)

{

	struct super_block *s;

	struct pts_fs_info *fsi;

	int error;



	s = sget(fs_type, compare_init_pts_sb, set_anon_super, NULL);

	if (IS_ERR(s))

		return PTR_ERR(s);



	if (!s->s_root) {

		s->s_flags = flags;

		error = devpts_fill_super(s, data, flags & MS_SILENT ? 1 : 0);

		if (error) {

			up_write(&s->s_umount);

			deactivate_super(s);

			return error;

		}

		s->s_flags |= MS_ACTIVE;

	}



	simple_set_mnt(mnt, s);



	fsi = DEVPTS_SB(mnt->mnt_sb);

	memcpy(&fsi->mount_opts, opts, sizeof(opts));



	return 0;

}



static int devpts_get_sb(struct file_system_type *fs_type,

	int flags, const char *dev_name, void *data, struct vfsmount *mnt)

{

	int error;

	struct pts_mount_opts opts;

	struct super_block *s;



	memset(&opts, 0, sizeof(opts));

	if (data) {
@@ -410,23 +363,37 @@ static int devpts_get_sb(struct file_system_type *fs_type, 
	}



	if (opts.newinstance)

		error = new_pts_mount(fs_type, flags, data, &opts, mnt);

		s = sget(fs_type, NULL, set_anon_super, NULL);

	else

		error = init_pts_mount(fs_type, flags, data, &opts, mnt);

		s = sget(fs_type, compare_init_pts_sb, set_anon_super, NULL);



	if (IS_ERR(s))

		return PTR_ERR(s);



	if (!s->s_root) {

		s->s_flags = flags;

		error = devpts_fill_super(s, data, flags & MS_SILENT ? 1 : 0);

		if (error)

		return error;

			goto out_undo_sget;

		s->s_flags |= MS_ACTIVE;

	}



	simple_set_mnt(mnt, s);



	memcpy(&(DEVPTS_SB(s))->mount_opts, &opts, sizeof(opts));



	error = mknod_ptmx(mnt->mnt_sb);

	error = mknod_ptmx(s);

	if (error)

		goto out_dput;



	return 0;



out_dput:

	dput(mnt->mnt_sb->s_root);

	up_write(&mnt->mnt_sb->s_umount);

	deactivate_super(mnt->mnt_sb);

	dput(s->s_root);



out_undo_sget:

	up_write(&s->s_umount);

	deactivate_super(s);

	return error;

}

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