From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756218AbZCGSOS (ORCPT ); Sat, 7 Mar 2009 13:14:18 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755690AbZCGSOA (ORCPT ); Sat, 7 Mar 2009 13:14:00 -0500 Received: from e6.ny.us.ibm.com ([32.97.182.146]:51770 "EHLO e6.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751443AbZCGSN7 (ORCPT ); Sat, 7 Mar 2009 13:13:59 -0500 Date: Sat, 7 Mar 2009 10:12:32 -0800 From: Sukadev Bhattiprolu To: Christoph Hellwig , Andrew Morton , Alan Cox Cc: serue@us.ibm.com, hpa@zytor.com, sukadev@us.ibm.com, linux-kernel@vger.kernel.org Subject: [v3][PATCH 5/5] Merge code for single and multiple-instance mounts Message-ID: <20090307181232.GF30072@us.ibm.com> References: <20090307180816.GA30072@us.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090307180816.GA30072@us.ibm.com> X-Operating-System: Linux 2.0.32 on an i486 User-Agent: Mutt/1.5.15+20070412 (2007-04-11) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Sukadev Bhattiprolu Subject: [v3][PATCH 5/5] 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: Sukadev Bhattiprolu Acked-by: Serge Hallyn Tested-by: Serge Hallyn --- fs/devpts/inode.c | 115 ++++++++++++++++++---------------------------------- 1 files changed, 40 insertions(+), 75 deletions(-) diff --git a/fs/devpts/inode.c b/fs/devpts/inode.c index c821c9a..c25fb34 100644 --- a/fs/devpts/inode.c +++ b/fs/devpts/inode.c @@ -325,87 +325,38 @@ 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; - - printk(KERN_NOTICE "devpts: newinstance mount\n"); - - 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() + * + * 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. * - * 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' option was not specified, mount/remount the + * initial kernel mount of devpts. This type of mount gives the + * legacy, single-instance semantics. * - * 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(). + * 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(). * - * Mounts with 'newinstance' option create a new private namespace. + * Mounts with 'newinstance' option create a new, private namespace. * - * But for single-mount semantics, devpts cannot use get_sb_single(), + * 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) { @@ -415,23 +366,37 @@ 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 (error) - return error; + if (IS_ERR(s)) + return PTR_ERR(s); - error = mknod_ptmx(mnt->mnt_sb); + if (!s->s_root) { + s->s_flags = flags; + error = devpts_fill_super(s, data, flags & MS_SILENT ? 1 : 0); + if (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(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; } -- 1.5.2.5