Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750762AbWHAX7v (ORCPT ); Tue, 1 Aug 2006 19:59:51 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750765AbWHAXwx (ORCPT ); Tue, 1 Aug 2006 19:52:53 -0400 Received: from e36.co.us.ibm.com ([32.97.110.154]:40395 "EHLO e36.co.us.ibm.com") by vger.kernel.org with ESMTP id S1750762AbWHAXwr (ORCPT ); Tue, 1 Aug 2006 19:52:47 -0400 Subject: [PATCH 06/28] reintroduce list of vfsmounts over superblock To: linux-kernel@vger.kernel.org Cc: viro@ftp.linux.org.uk, herbert@13thfloor.at, hch@infradead.org, Dave Hansen From: Dave Hansen Date: Tue, 01 Aug 2006 16:52:44 -0700 References: <20060801235240.82ADCA42@localhost.localdomain> In-Reply-To: <20060801235240.82ADCA42@localhost.localdomain> Message-Id: <20060801235244.964B79E7@localhost.localdomain> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3890 Lines: 97 We're moving a big chunk of the burden of keeping people from writing to r/o filesystems from the superblock into the vfsmount. This requires that we consult the superblock's vfsmounts when things like remounts occur. So, introduce a list of vfsmounts hanging off the superblock. We'll use this in a bit. Signed-off-by: Dave Hansen --- lxc-dave/fs/namespace.c | 12 ++++++++++++ lxc-dave/fs/super.c | 1 + lxc-dave/include/linux/fs.h | 1 + lxc-dave/include/linux/mount.h | 1 + 4 files changed, 15 insertions(+) diff -puN fs/namespace.c~C-reintroduce-list-of-vfsmounts-over-superblock fs/namespace.c --- lxc/fs/namespace.c~C-reintroduce-list-of-vfsmounts-over-superblock 2006-08-01 16:35:11.000000000 -0700 +++ lxc-dave/fs/namespace.c 2006-08-01 16:35:18.000000000 -0700 @@ -78,10 +78,18 @@ struct vfsmount *alloc_vfsmnt(const char return mnt; } +void add_mount_to_sb_list(struct vfsmount *mnt, struct super_block *sb) +{ + spin_lock(&vfsmount_lock); + list_add(&mnt->mnt_sb_list, &sb->s_vfsmounts); + spin_unlock(&vfsmount_lock); +} + int simple_set_mnt(struct vfsmount *mnt, struct super_block *sb) { mnt->mnt_sb = sb; mnt->mnt_root = dget(sb->s_root); + add_mount_to_sb_list(mnt, sb); return 0; } @@ -89,6 +97,9 @@ EXPORT_SYMBOL(simple_set_mnt); void free_vfsmnt(struct vfsmount *mnt) { + spin_lock(&vfsmount_lock); + list_del(&mnt->mnt_sb_list); + spin_unlock(&vfsmount_lock); kfree(mnt->mnt_devname); kmem_cache_free(mnt_cache, mnt); } @@ -242,6 +253,7 @@ static struct vfsmount *clone_mnt(struct mnt->mnt_root = dget(root); mnt->mnt_mountpoint = mnt->mnt_root; mnt->mnt_parent = mnt; + add_mount_to_sb_list(mnt, sb); if (flag & CL_SLAVE) { list_add(&mnt->mnt_slave, &old->mnt_slave_list); diff -puN fs/super.c~C-reintroduce-list-of-vfsmounts-over-superblock fs/super.c --- lxc/fs/super.c~C-reintroduce-list-of-vfsmounts-over-superblock 2006-08-01 16:35:11.000000000 -0700 +++ lxc-dave/fs/super.c 2006-08-01 16:35:18.000000000 -0700 @@ -67,6 +67,7 @@ static struct super_block *alloc_super(s INIT_LIST_HEAD(&s->s_dirty); INIT_LIST_HEAD(&s->s_io); INIT_LIST_HEAD(&s->s_files); + INIT_LIST_HEAD(&s->s_vfsmounts); INIT_LIST_HEAD(&s->s_instances); INIT_HLIST_HEAD(&s->s_anon); INIT_LIST_HEAD(&s->s_inodes); diff -puN include/linux/fs.h~C-reintroduce-list-of-vfsmounts-over-superblock include/linux/fs.h --- lxc/include/linux/fs.h~C-reintroduce-list-of-vfsmounts-over-superblock 2006-08-01 16:35:17.000000000 -0700 +++ lxc-dave/include/linux/fs.h 2006-08-01 16:35:18.000000000 -0700 @@ -962,6 +962,7 @@ struct super_block { struct list_head s_dirty; /* dirty inodes */ struct list_head s_io; /* parked for writeback */ struct hlist_head s_anon; /* anonymous dentries for (nfs) exporting */ + struct list_head s_vfsmounts; struct list_head s_files; struct block_device *s_bdev; diff -puN include/linux/mount.h~C-reintroduce-list-of-vfsmounts-over-superblock include/linux/mount.h --- lxc/include/linux/mount.h~C-reintroduce-list-of-vfsmounts-over-superblock 2006-08-01 16:35:11.000000000 -0700 +++ lxc-dave/include/linux/mount.h 2006-08-01 16:35:18.000000000 -0700 @@ -40,6 +40,7 @@ struct vfsmount { struct dentry *mnt_mountpoint; /* dentry of mountpoint */ struct dentry *mnt_root; /* root of the mounted tree */ struct super_block *mnt_sb; /* pointer to superblock */ + struct list_head mnt_sb_list; /* list of all mounts on same sb */ struct list_head mnt_mounts; /* list of children, anchored here */ struct list_head mnt_child; /* and going through their mnt_child */ atomic_t mnt_count; _ - 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/