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 <haveblue at us.ibm.com> --- lxc-dave/fs/namespace.c | 13 +++++++++++++ lxc-dave/fs/super.c | 1 + lxc-dave/include/linux/fs.h | 1 + lxc-dave/include/linux/mount.h | 1 + 4 files changed, 16 insertions(+) diff -puN fs/namespace.c~02-24-reintroduce-list-of-vfsmounts-over-superblock fs/namespace.c --- lxc/fs/namespace.c~02-24-reintroduce-list-of-vfsmounts-over-superblock 2006-12-11 14:21:57.000000000 -0800 +++ lxc-dave/fs/namespace.c 2006-12-11 14:21:57.000000000 -0800 @@ -77,9 +77,17 @@ 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_no_get(struct vfsmount *mnt, struct super_block *sb) { mnt->mnt_sb = sb; + add_mount_to_sb_list(mnt, sb); return 0; } @@ -95,6 +103,10 @@ EXPORT_SYMBOL(simple_set_mnt); void free_vfsmnt(struct vfsmount *mnt) { + spin_lock(&vfsmount_lock); + if (mnt->mnt_sb) + list_del(&mnt->mnt_sb_list); + spin_unlock(&vfsmount_lock); kfree(mnt->mnt_devname); kmem_cache_free(mnt_cache, mnt); } @@ -248,6 +260,7 @@ 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~02-24-reintroduce-list-of-vfsmounts-over-superblock fs/super.c --- lxc/fs/super.c~02-24-reintroduce-list-of-vfsmounts-over-superblock 2006-12-11 14:21:57.000000000 -0800 +++ lxc-dave/fs/super.c 2006-12-11 14:21:57.000000000 -0800 @@ -68,6 +68,7 @@ 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~02-24-reintroduce-list-of-vfsmounts-over-superblock include/linux/fs.h --- lxc/include/linux/fs.h~02-24-reintroduce-list-of-vfsmounts-over-superblock 2006-12-11 14:21:57.000000000 -0800 +++ lxc-dave/include/linux/fs.h 2006-12-11 14:21:57.000000000 -0800 @@ -967,6 +967,7 @@ 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~02-24-reintroduce-list-of-vfsmounts-over-superblock include/linux/mount.h --- lxc/include/linux/mount.h~02-24-reintroduce-list-of-vfsmounts-over-superblock 2006-12-11 14:21:57.000000000 -0800 +++ lxc-dave/include/linux/mount.h 2006-12-11 14:21:57.000000000 -0800 @@ -41,6 +41,7 @@ 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; _