Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762140AbYCZVXf (ORCPT ); Wed, 26 Mar 2008 17:23:35 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757598AbYCZVWF (ORCPT ); Wed, 26 Mar 2008 17:22:05 -0400 Received: from fxip-0047f.externet.hu ([88.209.222.127]:58473 "EHLO pomaz-ex.szeredi.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756680AbYCZVV6 (ORCPT ); Wed, 26 Mar 2008 17:21:58 -0400 Message-Id: <20080326212144.764829833@szeredi.hu> References: <20080326211131.705321084@szeredi.hu> User-Agent: quilt/0.45-1 Date: Wed, 26 Mar 2008 22:11:38 +0100 From: Miklos Szeredi To: viro@zeniv.linux.org.uk Cc: akpm@linux-foundation.org, linuxram@us.ibm.com, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [patch 7/7] vfs: mountinfo: show dominating group id Content-Disposition: inline; filename=mountinfo_dominator.patch Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4497 Lines: 125 From: Miklos Szeredi Show peer group ID of nearest dominating group that has intersection with the mount's namespace. Signed-off-by: Miklos Szeredi --- Documentation/filesystems/proc.txt | 6 ++++ fs/namespace.c | 9 +++++-- fs/pnode.c | 45 +++++++++++++++++++++++++++++++++++++ fs/pnode.h | 1 4 files changed, 59 insertions(+), 2 deletions(-) Index: vfs-2.6/Documentation/filesystems/proc.txt =================================================================== --- vfs-2.6.orig/Documentation/filesystems/proc.txt 2008-03-26 21:43:05.000000000 +0100 +++ vfs-2.6/Documentation/filesystems/proc.txt 2008-03-26 21:43:07.000000000 +0100 @@ -2375,8 +2375,14 @@ possible optional fields are: shared:X mount is shared in peer group X master:X mount is slave to peer group X +propagate_from:X mount is slave and receives propagation from peer group X (*) unbindable mount is unbindable +(*) X is the closest dominant peer group under the process's root. If +X is the immediate master of the mount, or if there's no dominant peer +group under the same root, then only the "master:X" field is present +and not the "propagate_from:X" field. + For more information on mount propagation see: Documentation/filesystems/sharedsubtree.txt Index: vfs-2.6/fs/namespace.c =================================================================== --- vfs-2.6.orig/fs/namespace.c 2008-03-26 21:43:05.000000000 +0100 +++ vfs-2.6/fs/namespace.c 2008-03-26 21:43:07.000000000 +0100 @@ -861,8 +861,13 @@ static int show_mountinfo(struct seq_fil /* Tagged fields ("foo:X" or "bar") */ if (IS_MNT_SHARED(mnt)) seq_printf(m, " shared:%i", mnt->mnt_group_id); - if (IS_MNT_SLAVE(mnt)) - seq_printf(m, " master:%i", mnt->mnt_master->mnt_group_id); + if (IS_MNT_SLAVE(mnt)) { + int master = mnt->mnt_master->mnt_group_id; + int dominator = get_dominator_id_same_root(mnt, &p->root); + seq_printf(m, " master:%i", master); + if (dominator && dominator != master) + seq_printf(m, " propagate_from:%i", dominator); + } if (IS_MNT_UNBINDABLE(mnt)) seq_puts(m, " unbindable"); Index: vfs-2.6/fs/pnode.c =================================================================== --- vfs-2.6.orig/fs/pnode.c 2008-03-26 21:41:12.000000000 +0100 +++ vfs-2.6/fs/pnode.c 2008-03-26 21:43:07.000000000 +0100 @@ -28,6 +28,51 @@ static inline struct vfsmount *next_slav return list_entry(p->mnt_slave.next, struct vfsmount, mnt_slave); } +/* + * Return true if path is reachable from root + * + * Caller must hold vfsmount_lock + */ +static bool is_path_reachable(struct vfsmount *mnt, struct dentry *dentry, + const struct path *root) +{ + while (mnt != root->mnt && mnt->mnt_parent != mnt) { + dentry = mnt->mnt_mountpoint; + mnt = mnt->mnt_parent; + } + return mnt == root->mnt && is_subdir(dentry, root->dentry); +} + +static struct vfsmount *get_peer_under_root(struct vfsmount *mnt, + struct mnt_namespace *ns, + const struct path *root) +{ + struct vfsmount *m = mnt; + + do { + /* Check the namespace first for optimization */ + if (m->mnt_ns == ns && is_path_reachable(m, m->mnt_root, root)) + return m; + + m = next_peer(m); + } while (m != mnt); + + return NULL; +} + +int get_dominator_id_same_root(struct vfsmount *mnt, const struct path *root) +{ + struct vfsmount *m; + + for (m = mnt->mnt_master; m != NULL; m = m->mnt_master) { + struct vfsmount *d = get_peer_under_root(m, mnt->mnt_ns, root); + if (d) + return d->mnt_group_id; + } + + return 0; +} + static int do_make_slave(struct vfsmount *mnt) { struct vfsmount *peer_mnt = mnt, *master = mnt->mnt_master; Index: vfs-2.6/fs/pnode.h =================================================================== --- vfs-2.6.orig/fs/pnode.h 2008-03-26 21:39:49.000000000 +0100 +++ vfs-2.6/fs/pnode.h 2008-03-26 21:43:07.000000000 +0100 @@ -36,4 +36,5 @@ int propagate_mnt(struct vfsmount *, str int propagate_umount(struct list_head *); int propagate_mount_busy(struct vfsmount *, int); void mnt_release_group_id(struct vfsmount *); +int get_dominator_id_same_root(struct vfsmount *mnt, const struct path *root); #endif /* _LINUX_PNODE_H */ -- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/