From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262465AbVGHKsX (ORCPT ); Fri, 8 Jul 2005 06:48:23 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262459AbVGHKsU (ORCPT ); Fri, 8 Jul 2005 06:48:20 -0400 Received: from e32.co.us.ibm.com ([32.97.110.130]:9399 "EHLO e32.co.us.ibm.com") by vger.kernel.org with ESMTP id S262464AbVGHKZ5 (ORCPT ); Fri, 8 Jul 2005 06:25:57 -0400 Subject: [RFC PATCH 3/8] bind/rbind a shared/private/slave/unclone tree From: Ram To: linux-kernel@vger.kernel.org Cc: linux-fsdevel@vger.kernel.org, viro@parcelfarce.linux.theplanet.co.uk, Andrew Morton , mike@waychison.com, bfields@fieldses.org, Miklos Szeredi In-Reply-To: <1120816436.30164.19.camel@localhost> References: <1120816072.30164.10.camel@localhost> <1120816229.30164.13.camel@localhost> <1120816355.30164.16.camel@localhost> <1120816436.30164.19.camel@localhost> Content-Type: multipart/mixed; boundary="=-00CL9+fUmHQGgsZyy2Am" Organization: IBM Message-Id: <1120817590.30164.47.camel@localhost> Mime-Version: 1.0 X-Mailer: Ximian Evolution 1.4.6 Date: Fri, 08 Jul 2005 03:25:47 -0700 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org --=-00CL9+fUmHQGgsZyy2Am Content-Type: text/plain Content-Transfer-Encoding: 7bit Adds the ability to bind/rbind a shared/private/slave subtree and set up propogation wherever needed. RP --=-00CL9+fUmHQGgsZyy2Am Content-Disposition: attachment; filename=rbind.patch Content-Type: text/x-patch; name=rbind.patch Content-Transfer-Encoding: 7bit Adds the ability to bind/rbind a shared/private/slave subtree and set up propogation wherever needed. RP Signed by Ram Pai (linuxram@us.ibm.com) fs/namespace.c | 510 ++++++++++++++++++++++++++++++++++++++++---------- fs/pnode.c | 244 +++++++++++++++++++++++ include/linux/fs.h | 4 include/linux/pnode.h | 5 4 files changed, 664 insertions(+), 99 deletions(-) Index: 2.6.12/fs/namespace.c =================================================================== --- 2.6.12.orig/fs/namespace.c +++ 2.6.12/fs/namespace.c @@ -42,7 +42,8 @@ static inline int sysfs_init(void) static struct list_head *mount_hashtable; static int hash_mask, hash_bits; -static kmem_cache_t *mnt_cache; +static kmem_cache_t *mnt_cache; +static struct rw_semaphore namespace_sem; static inline unsigned long hash(struct vfsmount *mnt, struct dentry *dentry) { @@ -54,7 +55,7 @@ static inline unsigned long hash(struct struct vfsmount *alloc_vfsmnt(const char *name) { - struct vfsmount *mnt = kmem_cache_alloc(mnt_cache, GFP_KERNEL); + struct vfsmount *mnt = kmem_cache_alloc(mnt_cache, GFP_KERNEL); if (mnt) { memset(mnt, 0, sizeof(struct vfsmount)); atomic_set(&mnt->mnt_count,1); @@ -109,6 +110,32 @@ struct vfsmount *lookup_mnt(struct vfsmo return found; } +static struct vfsmount * +clone_mnt(struct vfsmount *old, struct dentry *root) +{ + struct super_block *sb = old->mnt_sb; + struct vfsmount *mnt = alloc_vfsmnt(old->mnt_devname); + + if (mnt) { + mnt->mnt_flags = old->mnt_flags; + atomic_inc(&sb->s_active); + mnt->mnt_sb = sb; + mnt->mnt_root = dget(root); + mnt->mnt_mountpoint = mnt->mnt_root; + mnt->mnt_parent = mnt; + mnt->mnt_namespace = old->mnt_namespace; + mnt->mnt_pnode = get_pnode(old->mnt_pnode); + + /* stick the duplicate mount on the same expiry list + * as the original if that was on one */ + spin_lock(&vfsmount_lock); + if (!list_empty(&old->mnt_fslink)) + list_add(&mnt->mnt_fslink, &old->mnt_fslink); + spin_unlock(&vfsmount_lock); + } + return mnt; +} + static inline int check_mnt(struct vfsmount *mnt) { return mnt->mnt_namespace == current->namespace; @@ -122,7 +149,6 @@ static void detach_mnt(struct vfsmount * mnt->mnt_mountpoint = mnt->mnt_root; list_del_init(&mnt->mnt_child); list_del_init(&mnt->mnt_hash); - list_del_init(&mnt->mnt_pnode_mntlist); old_nd->dentry->d_mounted--; } @@ -130,11 +156,68 @@ static void attach_mnt(struct vfsmount * { mnt->mnt_parent = mntget(nd->mnt); mnt->mnt_mountpoint = dget(nd->dentry); + mnt->mnt_namespace = nd->mnt->mnt_namespace; list_add(&mnt->mnt_hash, mount_hashtable+hash(nd->mnt, nd->dentry)); list_add_tail(&mnt->mnt_child, &nd->mnt->mnt_mounts); nd->dentry->d_mounted++; } +static struct vfsmount *do_attach_mnt(struct vfsmount *mnt, + struct dentry *dentry, + struct vfsmount *child_mnt) +{ + struct nameidata nd; + LIST_HEAD(head); + + nd.mnt = mnt; + nd.dentry = dentry; + attach_mnt(child_mnt, &nd); + list_add_tail(&head, &child_mnt->mnt_list); + list_splice(&head, child_mnt->mnt_namespace->list.prev); + return child_mnt; +} + +static void attach_prepare_mnt(struct vfsmount *mnt, struct nameidata *nd) +{ + mnt->mnt_parent = mntget(nd->mnt); + mnt->mnt_mountpoint = dget(nd->dentry); + nd->dentry->d_mounted++; +} + +void do_attach_real_mnt(struct vfsmount *mnt) +{ + struct vfsmount *parent = mnt->mnt_parent; + BUG_ON(parent==mnt); + if(list_empty(&mnt->mnt_hash)) + list_add(&mnt->mnt_hash, + mount_hashtable+hash(parent, mnt->mnt_mountpoint)); + if(list_empty(&mnt->mnt_child)) + list_add_tail(&mnt->mnt_child, &parent->mnt_mounts); + mnt->mnt_namespace = parent->mnt_namespace; + list_add_tail(&mnt->mnt_list, &mnt->mnt_namespace->list); +} + +struct vfsmount *do_attach_prepare_mnt(struct vfsmount *mnt, + struct dentry *dentry, + struct vfsmount *template_mnt, + int clone_flag) +{ + struct vfsmount *child_mnt; + struct nameidata nd; + + if (clone_flag) + child_mnt = clone_mnt(template_mnt, template_mnt->mnt_root); + else + child_mnt = template_mnt; + + nd.mnt = mnt; + nd.dentry = dentry; + + attach_prepare_mnt(child_mnt, &nd); + + return child_mnt; +} + static struct vfsmount *next_mnt(struct vfsmount *p, struct vfsmount *root) { struct list_head *next = p->mnt_mounts.next; @@ -151,37 +234,20 @@ static struct vfsmount *next_mnt(struct return list_entry(next, struct vfsmount, mnt_child); } -static struct vfsmount * -clone_mnt(struct vfsmount *old, struct dentry *root) +static struct vfsmount *skip_mnt_tree(struct vfsmount *p) { - struct super_block *sb = old->mnt_sb; - struct vfsmount *mnt = alloc_vfsmnt(old->mnt_devname); - - if (mnt) { - mnt->mnt_flags = old->mnt_flags; - atomic_inc(&sb->s_active); - mnt->mnt_sb = sb; - mnt->mnt_root = dget(root); - mnt->mnt_mountpoint = mnt->mnt_root; - mnt->mnt_parent = mnt; - mnt->mnt_namespace = old->mnt_namespace; - mnt->mnt_pnode = get_pnode(old->mnt_pnode); - - /* stick the duplicate mount on the same expiry list - * as the original if that was on one */ - spin_lock(&vfsmount_lock); - if (!list_empty(&old->mnt_fslink)) - list_add(&mnt->mnt_fslink, &old->mnt_fslink); - spin_unlock(&vfsmount_lock); + struct list_head *prev = p->mnt_mounts.prev; + while (prev != &p->mnt_mounts) { + p = list_entry(prev, struct vfsmount, mnt_child); + prev = p->mnt_mounts.prev; } - return mnt; + return p; } void __mntput(struct vfsmount *mnt) { struct super_block *sb = mnt->mnt_sb; dput(mnt->mnt_root); - put_pnode(mnt->mnt_pnode); free_vfsmnt(mnt); deactivate_super(sb); } @@ -195,7 +261,7 @@ static void *m_start(struct seq_file *m, struct list_head *p; loff_t l = *pos; - down_read(&n->sem); + down_read(&namespace_sem); list_for_each(p, &n->list) if (!l--) return list_entry(p, struct vfsmount, mnt_list); @@ -212,8 +278,7 @@ static void *m_next(struct seq_file *m, static void m_stop(struct seq_file *m, void *v) { - struct namespace *n = m->private; - up_read(&n->sem); + up_read(&namespace_sem); } static inline void mangle(struct seq_file *m, const char *s) @@ -437,7 +502,7 @@ static int do_umount(struct vfsmount *mn return retval; } - down_write(¤t->namespace->sem); + down_write(&namespace_sem); spin_lock(&vfsmount_lock); if (atomic_read(&sb->s_active) == 1) { @@ -459,7 +524,7 @@ static int do_umount(struct vfsmount *mn spin_unlock(&vfsmount_lock); if (retval) security_sb_umount_busy(mnt); - up_write(¤t->namespace->sem); + up_write(&namespace_sem); return retval; } @@ -499,9 +564,9 @@ out: #ifdef __ARCH_WANT_SYS_OLDUMOUNT /* - * The 2.0 compatible umount. No flags. + * The 2.0 compatible umount. No flags. */ - + asmlinkage long sys_oldumount(char __user * name) { return sys_umount(name,0); @@ -545,6 +610,9 @@ static struct vfsmount *copy_tree(struct struct list_head *h; struct nameidata nd; + if (IS_MNT_UNCLONABLE(mnt)) + return NULL; + res = q = clone_mnt(mnt, dentry); if (!q) goto Enomem; @@ -553,10 +621,15 @@ static struct vfsmount *copy_tree(struct p = mnt; for (h = mnt->mnt_mounts.next; h != &mnt->mnt_mounts; h = h->next) { r = list_entry(h, struct vfsmount, mnt_child); + if (!lives_below_in_same_fs(r->mnt_mountpoint, dentry)) continue; for (s = r; s; s = next_mnt(s, r)) { + if (IS_MNT_UNCLONABLE(s)) { + s = skip_mnt_tree(s); + continue; + } while (p != s->mnt_parent) { p = p->mnt_parent; q = q->mnt_parent; @@ -583,9 +656,163 @@ static struct vfsmount *copy_tree(struct return NULL; } + /* + * @source_mnt : mount tree to be attached + * @nd : place the mount tree @source_mnt is attached + * + * NOTE: in the table below explains the semantics when a source vfsmount + * of a given type is attached to a destination vfsmount of a give type. + * ----------------------------------------------------------------------------- + * | BIND MOUNT OPERATION | + * |***************************************************************************| + * | dest --> | shared | private | slave |unclonable | + * | source | | | | | + * | | | | | | | + * | v | | | | | + * |***************************************************************************| + * | | | | | | + * | shared | shared (++) | shared (+) | shared (+) | shared (+)| + * | | | | | | + * | | | | | | + * | private | shared (+) | private | private | private | + * | | | | | | + * | | | | | | + * | slave | shared (+) | private | private | private | + * | | | | | | + * | | | | | | + * | unclonable| - | - | - | - | + * | | | | | | + * | | | | | | + * *************************************************************************** + * + * (++) the mount will be propogated to all the vfsmounts in the pnode tree + * of the destination vfsmount, and all the non-slave new mounts in + * destination vfsmount will be added the source vfsmount's pnode. + * (+) the mount will be propogated to the destination vfsmount + * and the new mount will be added to the source vfsmount's pnode. + * + * if the source mount is a tree, the operations explained above is applied to each + * vfsmount in the tree. + * + * Should be called without spinlocks held, because this function can sleep + * in allocations. + * + */ +static void +attach_recursive_mnt(struct vfsmount *source_mnt, struct nameidata *nd) +{ + struct vfsmount *mntpt_mnt, *m, *p; + struct vfspnode *src_pnode, *t_p, *dest_pnode, *tmp_pnode; + struct dentry *mntpt_dentry; + LIST_HEAD(pnodehead); + + mntpt_mnt = nd->mnt; + dest_pnode = IS_MNT_SHARED(mntpt_mnt) ? mntpt_mnt->mnt_pnode : NULL; + src_pnode = IS_MNT_SHARED(source_mnt) ? source_mnt->mnt_pnode : NULL; + + if (!dest_pnode && !src_pnode) { + LIST_HEAD(head); + spin_lock(&vfsmount_lock); + do_attach_mnt(nd->mnt, nd->dentry, source_mnt); + spin_unlock(&vfsmount_lock); + goto out; + } + + /* + * Ok, the source or the destination pnode exists. + * Get ready for pnode operations. + * Create a temporary pnode which shall hold all the + * new mounts. Merge or delete or slave that pnode + * later in a separate operation, depending on + * the type of source and destination mounts. + */ + p = NULL; + for (m = source_mnt; m; m = next_mnt(m, source_mnt)) { + int unclone = IS_MNT_UNCLONABLE(m); + + list_del_init(&m->mnt_list); + + while (p && p != m->mnt_parent) { + p = p->mnt_parent; + } + + if (!p) { + mntpt_dentry = nd->dentry; + mntpt_mnt = nd->mnt; + } else { + mntpt_dentry = m->mnt_mountpoint; + mntpt_mnt = p; + } + + p=m; + dest_pnode = IS_MNT_SHARED(mntpt_mnt) ? + mntpt_mnt->mnt_pnode : NULL; + src_pnode = (IS_MNT_SHARED(m))? + m->mnt_pnode : NULL; + + m->mnt_pnode = NULL; + /* + * get a temporary pnode into which add the new vfs, and keep + * track of these pnodes and their real pnode. + */ + while (!(tmp_pnode = pnode_alloc())) + schedule(); + + + if (dest_pnode && !unclone) + pnode_prepare_mount(dest_pnode, tmp_pnode, + mntpt_dentry, m, mntpt_mnt); + else { + if (m == m->mnt_parent) + do_attach_prepare_mnt(mntpt_mnt, + mntpt_dentry, m, 0); + pnode_add_member_mnt(tmp_pnode, m); + if (unclone) + SET_MNT_UNCLONABLE(m); + } + + if ((!src_pnode && !dest_pnode) || unclone) + SET_PNODE_DELETE(tmp_pnode); + tmp_pnode->pnode_master = src_pnode; + /* + * temporarily track the pnode with which the tmp_pnode + * has to merge with; in the pnode_master field. + */ + list_add_tail(&tmp_pnode->pnode_peer_slave, &pnodehead); + } + + /* + * new mounts. Merge or delete or slave the temporary pnode + */ + spin_lock(&vfsmount_lock); + list_for_each_entry_safe(tmp_pnode, t_p, &pnodehead, pnode_peer_slave) { + int del_flag = IS_PNODE_DELETE(tmp_pnode); + struct vfspnode *master_pnode = tmp_pnode->pnode_master; + list_del_init(&tmp_pnode->pnode_peer_slave); + pnode_real_mount(tmp_pnode, del_flag); + if (!del_flag && master_pnode) { + tmp_pnode->pnode_master = NULL; + pnode_merge_pnode(tmp_pnode, master_pnode); + /* + * we don't need the extra reference to + * the master_pnode, that was created either + * (a) pnode_add_slave_pnode: when the mnt was made as + * a slave mnt. + * (b) pnode_merge_pnode: during clone_mnt(). + */ + put_pnode(master_pnode); + } + } + spin_unlock(&vfsmount_lock); +out: + mntget(source_mnt); + return; +} + static int graft_tree(struct vfsmount *mnt, struct nameidata *nd) { - int err; + int err, ret; + if (mnt->mnt_sb->s_flags & MS_NOUSER) return -EINVAL; @@ -603,17 +830,14 @@ static int graft_tree(struct vfsmount *m goto out_unlock; err = -ENOENT; - spin_lock(&vfsmount_lock); - if (IS_ROOT(nd->dentry) || !d_unhashed(nd->dentry)) { - struct list_head head; - attach_mnt(mnt, nd); - list_add_tail(&head, &mnt->mnt_list); - list_splice(&head, current->namespace->list.prev); - mntget(mnt); + spin_lock(&vfsmount_lock); + ret = (IS_ROOT(nd->dentry) || !d_unhashed(nd->dentry)); + spin_unlock(&vfsmount_lock); + if (ret) { + attach_recursive_mnt(mnt, nd); err = 0; } - spin_unlock(&vfsmount_lock); out_unlock: up(&nd->dentry->d_inode->i_sem); if (!err) @@ -621,6 +845,11 @@ out_unlock: return err; } + /* + * create a new mount at the dentry, and move all child mounts + * underneath it, if those mounts were below the dentry on the + * parent mount. + */ struct vfsmount *do_make_mounted(struct vfsmount *mnt, struct dentry *dentry) { struct vfsmount *child_mnt, *next; @@ -628,6 +857,14 @@ struct vfsmount *do_make_mounted(struct struct vfsmount *newmnt = clone_mnt(mnt, dentry); LIST_HEAD(move); + /* + * note clone_mnt() gets a reference to the pnode. + * we won't use that pnode anyway. So just let it + * go + */ + put_pnode(newmnt->mnt_pnode); + newmnt->mnt_pnode = NULL; + if (newmnt) { /* put in code for mount expiry */ /* TOBEDONE */ @@ -653,14 +890,41 @@ struct vfsmount *do_make_mounted(struct nd.mnt = mnt; nd.dentry = dentry; - attach_mnt(newmnt, &nd); + do_attach_mnt(nd.mnt, nd.dentry, newmnt); spin_unlock(&vfsmount_lock); } return newmnt; } -int -_do_make_mounted(struct nameidata *nd, struct vfsmount **mnt) +int do_make_unmounted(struct vfsmount *mnt) +{ + struct vfsmount *parent_mnt, *child_mnt, *next; + struct nameidata nd; + + /* validate if mount has a different parent */ + parent_mnt = mnt->mnt_parent; + if (mnt == parent_mnt) + return 0; + /* + * cannot unmount a mount that is not created + * as a overlay mount. + */ + if (mnt->mnt_mountpoint != mnt->mnt_root) + return -EINVAL; + + /* for each submounts in the parent, put the mounts back */ + spin_lock(&vfsmount_lock); + list_for_each_entry_safe(child_mnt, next, &mnt->mnt_mounts, mnt_child) { + detach_mnt(child_mnt, &nd); + nd.mnt = parent_mnt; + attach_mnt(child_mnt, &nd); + } + detach_mnt(mnt, &nd); + spin_unlock(&vfsmount_lock); + return 0; +} + +int make_mounted(struct nameidata *nd, struct vfsmount **mnt) { struct vfsmount *parent_mnt; struct dentry *parent_dentry; @@ -671,9 +935,10 @@ _do_make_mounted(struct nameidata *nd, s parent_mnt = nd->mnt; /* * check if dentry already has a vfsmount - * if it does not, create a vfsmount there. - * which means you need to propogate it - * across all vfsmounts. + * if it does not, create and attach + * a new vfsmount at that dentry. + * Also propogate the mount if parent_mnt + * is shared. */ if(parent_dentry == parent_mnt->mnt_root) { *mnt = parent_mnt; @@ -688,6 +953,25 @@ _do_make_mounted(struct nameidata *nd, s return err; } +int make_unmounted(struct vfsmount *mnt) +{ + if (mnt == mnt->mnt_parent) + return 0; + /* + * cannot unmount a mount that is not created + * as a overlay mount. + */ + if (mnt->mnt_mountpoint != mnt->mnt_root) + return -EINVAL; + + if (IS_MNT_SHARED(mnt)) + pnode_make_unmounted(mnt->mnt_pnode); + else + do_make_unmounted(mnt); + + return 0; +} + /* * recursively change the type of the mountpoint. */ @@ -702,7 +986,7 @@ static int do_change_type(struct nameida && !(flag & MS_SLAVE)) return -EINVAL; - if ((err = _do_make_mounted(nd, &mnt))) + if ((err = make_mounted(nd, &mnt))) return err; spin_lock(&vfsmount_lock); @@ -735,9 +1019,8 @@ static int do_change_type(struct nameida break; case MS_SLAVE: - if (IS_MNT_SLAVE(m)) { + if (IS_MNT_SLAVE(m)) break; - } /* * only shared mounts can * be made slave @@ -775,7 +1058,7 @@ static int do_change_type(struct nameida static int do_loopback(struct nameidata *nd, char *old_name, int recurse) { struct nameidata old_nd; - struct vfsmount *mnt = NULL; + struct vfsmount *mnt = NULL, *overlay_mnt=NULL; int err = mount_is_safe(nd); if (err) return err; @@ -785,14 +1068,31 @@ static int do_loopback(struct nameidata if (err) return err; - down_write(¤t->namespace->sem); + if (IS_MNT_UNCLONABLE(old_nd.mnt)) { + err = -EINVAL; + goto path_release; + } + + down_write(&namespace_sem); err = -EINVAL; if (check_mnt(nd->mnt) && (!recurse || check_mnt(old_nd.mnt))) { + + /* + * If the dentry is not the root dentry, and if a bind + * from a shared subtree is attempted, create a mount + * at the dentry, and use the new mount as the starting + * point for the bind/rbind operation. + */ + overlay_mnt = old_nd.mnt; + if(IS_MNT_SHARED(old_nd.mnt) && + (err = make_mounted(&old_nd, &overlay_mnt))) + goto out; + err = -ENOMEM; if (recurse) - mnt = copy_tree(old_nd.mnt, old_nd.dentry); + mnt = copy_tree(overlay_mnt, old_nd.dentry); else - mnt = clone_mnt(old_nd.mnt, old_nd.dentry); + mnt = clone_mnt(overlay_mnt, old_nd.dentry); } if (mnt) { @@ -803,15 +1103,25 @@ static int do_loopback(struct nameidata err = graft_tree(mnt, nd); if (err) { - spin_lock(&vfsmount_lock); - umount_tree(mnt); - spin_unlock(&vfsmount_lock); - } else - mntput(mnt); - } + spin_lock(&vfsmount_lock); + umount_tree(mnt); + spin_unlock(&vfsmount_lock); + /* + * ok we failed! so undo any overlay + * mount that we did earlier. + */ + if (old_nd.mnt != overlay_mnt) + make_unmounted(overlay_mnt); + } else + mntput(mnt); + } + + out: + up_write(&namespace_sem); + + path_release: + path_release(&old_nd); - up_write(¤t->namespace->sem); - path_release(&old_nd); return err; } @@ -859,7 +1169,7 @@ static int do_move_mount(struct nameidat if (err) return err; - down_write(¤t->namespace->sem); + down_write(&namespace_sem); while(d_mountpoint(nd->dentry) && follow_down(&nd->mnt, &nd->dentry)) ; err = -EINVAL; @@ -903,7 +1213,7 @@ out2: out1: up(&nd->dentry->d_inode->i_sem); out: - up_write(¤t->namespace->sem); + up_write(&namespace_sem); if (!err) path_release(&parent_nd); path_release(&old_nd); @@ -942,7 +1252,7 @@ int do_add_mount(struct vfsmount *newmnt { int err; - down_write(¤t->namespace->sem); + down_write(&namespace_sem); /* Something was mounted here while we slept */ while(d_mountpoint(nd->dentry) && follow_down(&nd->mnt, &nd->dentry)) ; @@ -971,7 +1281,7 @@ int do_add_mount(struct vfsmount *newmnt } unlock: - up_write(¤t->namespace->sem); + up_write(&namespace_sem); mntput(newmnt); return err; } @@ -1027,7 +1337,7 @@ void mark_mounts_for_expiry(struct list_ get_namespace(namespace); spin_unlock(&vfsmount_lock); - down_write(&namespace->sem); + down_write(&namespace_sem); spin_lock(&vfsmount_lock); /* check that it is still dead: the count should now be 2 - as @@ -1071,7 +1381,7 @@ void mark_mounts_for_expiry(struct list_ spin_unlock(&vfsmount_lock); } - up_write(&namespace->sem); + up_write(&namespace_sem); mntput(mnt); put_namespace(namespace); @@ -1117,7 +1427,7 @@ int copy_mount_options(const void __user int i; unsigned long page; unsigned long size; - + *where = 0; if (!data) return 0; @@ -1136,7 +1446,7 @@ int copy_mount_options(const void __user i = size - exact_copy_from_user((void *)page, data, size); if (!i) { - free_page(page); + free_page(page); return -EFAULT; } if (i != PAGE_SIZE) @@ -1242,14 +1552,13 @@ int copy_namespace(int flags, struct tas goto out; atomic_set(&new_ns->count, 1); - init_rwsem(&new_ns->sem); INIT_LIST_HEAD(&new_ns->list); - down_write(&tsk->namespace->sem); + down_write(&namespace_sem); /* First pass: copy the tree topology */ new_ns->root = copy_tree(namespace->root, namespace->root->mnt_root); if (!new_ns->root) { - up_write(&tsk->namespace->sem); + up_write(&namespace_sem); kfree(new_ns); goto out; } @@ -1283,7 +1592,7 @@ int copy_namespace(int flags, struct tas p = next_mnt(p, namespace->root); q = next_mnt(q, new_ns->root); } - up_write(&tsk->namespace->sem); + up_write(&namespace_sem); tsk->namespace = new_ns; @@ -1465,7 +1774,7 @@ asmlinkage long sys_pivot_root(const cha user_nd.mnt = mntget(current->fs->rootmnt); user_nd.dentry = dget(current->fs->root); read_unlock(¤t->fs->lock); - down_write(¤t->namespace->sem); + down_write(&namespace_sem); down(&old_nd.dentry->d_inode->i_sem); error = -EINVAL; if (!check_mnt(user_nd.mnt)) @@ -1511,7 +1820,7 @@ asmlinkage long sys_pivot_root(const cha path_release(&parent_nd); out2: up(&old_nd.dentry->d_inode->i_sem); - up_write(¤t->namespace->sem); + up_write(&namespace_sem); path_release(&user_nd); path_release(&old_nd); out1: @@ -1538,7 +1847,6 @@ static void __init init_mount_tree(void) panic("Can't allocate initial namespace"); atomic_set(&namespace->count, 1); INIT_LIST_HEAD(&namespace->list); - init_rwsem(&namespace->sem); list_add(&mnt->mnt_list, &namespace->list); namespace->root = mnt; mnt->mnt_namespace = namespace; @@ -1561,6 +1869,8 @@ void __init mnt_init(unsigned long mempa unsigned int nr_hash; int i; + init_rwsem(&namespace_sem); + mnt_cache = kmem_cache_create("mnt_cache", sizeof(struct vfsmount), 0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL); @@ -1608,7 +1918,7 @@ void __put_namespace(struct namespace *n { struct vfsmount *mnt; - down_write(&namespace->sem); + down_write(&namespace_sem); spin_lock(&vfsmount_lock); list_for_each_entry(mnt, &namespace->list, mnt_list) { @@ -1617,6 +1927,6 @@ void __put_namespace(struct namespace *n umount_tree(namespace->root); spin_unlock(&vfsmount_lock); - up_write(&namespace->sem); + up_write(&namespace_sem); kfree(namespace); } Index: 2.6.12/fs/pnode.c =================================================================== --- 2.6.12.orig/fs/pnode.c +++ 2.6.12/fs/pnode.c @@ -287,6 +287,52 @@ pnode_disassociate_mnt(struct vfsmount * mnt->mnt_flags &= ~MNT_SHARED; } +// merge pnode into peer_pnode and get rid of pnode +int +pnode_merge_pnode(struct vfspnode *pnode, struct vfspnode *peer_pnode) +{ + struct vfspnode *slave_pnode, *pnext; + struct vfsmount *mnt, *slave_mnt, *next; + int i,count; + + spin_lock(&vfspnode_lock); + list_for_each_entry_safe(slave_pnode, pnext, + &pnode->pnode_slavepnode, pnode_peer_slave) { + slave_pnode->pnode_master = peer_pnode; + list_move(&slave_pnode->pnode_peer_slave, + &peer_pnode->pnode_slavepnode); + } + + list_for_each_entry_safe(slave_mnt, next, + &pnode->pnode_slavevfs, mnt_pnode_mntlist) { + slave_mnt->mnt_pnode = peer_pnode; + list_move(&slave_mnt->mnt_pnode_mntlist, + &peer_pnode->pnode_slavevfs); + } + + list_for_each_entry_safe(mnt, next, + &pnode->pnode_vfs, mnt_pnode_mntlist) { + mnt->mnt_pnode = peer_pnode; + list_move(&mnt->mnt_pnode_mntlist, + &peer_pnode->pnode_vfs); + } + + count = atomic_read(&pnode->pnode_count); + atomic_add(count, &peer_pnode->pnode_count); + spin_unlock(&vfspnode_lock); + + /* + * delete all references to 'pnode'. + * A better implementation can simply + * call free_pnode(pnode). But this is + * a cleaner way of doing it. Offcourse + * with some cost. + */ + for (i=0 ; i mnt_pnode; + list_del_init(&mnt->mnt_pnode_mntlist); + put_pnode(pnode); +out: + return ret; +} + +int +pnode_make_unmounted(struct vfspnode *pnode) +{ + int ret=0,traversal; + struct vfsmount *slave_mnt, *member_mnt, *t_m; + struct pcontext context; + + context.start = pnode; + context.pnode = NULL; + while(pnode_next(&context)) { + traversal = context.traversal; + pnode = context.pnode; + if(traversal == PNODE_UP) { + // traverse member vfsmounts + spin_lock(&vfspnode_lock); + list_for_each_entry_safe(member_mnt, + t_m, &pnode->pnode_vfs, mnt_pnode_mntlist) { + spin_unlock(&vfspnode_lock); + if ((ret = vfs_make_unmounted(member_mnt))) + goto out; + spin_lock(&vfspnode_lock); + } + list_for_each_entry_safe(slave_mnt, + t_m, &pnode->pnode_slavevfs, mnt_pnode_mntlist) { + spin_unlock(&vfspnode_lock); + if ((ret = vfs_make_unmounted(slave_mnt))) + goto out; + spin_lock(&vfspnode_lock); + } + spin_unlock(&vfspnode_lock); + } + } + +out: + return ret; +} + + +int +vfs_prepare_mount_func(struct vfsmount *mnt, int flag, struct vfspnode *pnode, + struct vfsmount *source_mnt, + struct dentry *mountpoint_dentry, + struct vfsmount *p_mnt) + +{ + struct vfsmount *child_mnt; + + if ((p_mnt != mnt) || (source_mnt == source_mnt->mnt_parent)) { + child_mnt = do_attach_prepare_mnt(mnt, mountpoint_dentry, + source_mnt, (p_mnt != mnt)); + if (child_mnt != source_mnt) + put_pnode(source_mnt->mnt_pnode); + } else + child_mnt = source_mnt; + + switch (flag) { + case PNODE_SLAVE_VFS : + pnode_add_slave_mnt(pnode, child_mnt); + break; + case PNODE_MEMBER_VFS : + pnode_add_member_mnt(pnode, child_mnt); + break; + } + + return 0; +} + + +int +pnode_prepare_mount(struct vfspnode *pnode, + struct vfspnode *master_child_pnode, + struct dentry *mountpoint_dentry, + struct vfsmount *source_mnt, + struct vfsmount *mnt) +{ + int ret=0,traversal,level; + struct vfspnode *slave_pnode, *master_pnode, *slave_child_pnode, *child_pnode; + struct vfsmount *slave_mnt, *member_mnt, *t_m; + struct pcontext context; + static struct inoutdata p_array[PNODE_MAX_SLAVE_LEVEL]; + + context.start = pnode; + context.pnode = NULL; + while(pnode_next(&context)) { + traversal = context.traversal; + level = context.level; + pnode = context.pnode; + slave_pnode = context.slave_pnode; + master_pnode = context.master_pnode; + + if (traversal == PNODE_DOWN ) { + + child_pnode = NULL; + if (!master_pnode) + child_pnode = master_child_pnode; + + while (!(child_pnode = pnode_alloc())) + schedule(); + + p_array[level].my_data = child_pnode; + + } else if(traversal == PNODE_MID) { + + child_pnode = (struct vfspnode *)p_array[level].my_data; + slave_child_pnode = p_array[level+1].out_data; + pnode_add_slave_pnode(child_pnode, slave_child_pnode); + + } else if(traversal == PNODE_UP) { + + child_pnode = p_array[level].my_data; + spin_lock(&vfspnode_lock); + list_for_each_entry_safe(member_mnt, + t_m, &pnode->pnode_vfs, mnt_pnode_mntlist) { + spin_unlock(&vfspnode_lock); + if((ret=vfs_prepare_mount_func(member_mnt, + PNODE_MEMBER_VFS, child_pnode, source_mnt, + mountpoint_dentry, mnt))) + goto out; + spin_lock(&vfspnode_lock); + } + list_for_each_entry_safe(slave_mnt, + t_m, &pnode->pnode_slavevfs, mnt_pnode_mntlist) { + spin_unlock(&vfspnode_lock); + if((ret = vfs_prepare_mount_func(slave_mnt, + PNODE_SLAVE_VFS, child_pnode, source_mnt, + mountpoint_dentry, mnt))) + goto out; + spin_lock(&vfspnode_lock); + } + spin_unlock(&vfspnode_lock); + p_array[level].out_data = child_pnode; + + } + } + +out: + return ret; +} + + +int +vfs_real_mount_func(struct vfsmount *mnt, int delflag) +{ + BUG_ON(mnt == mnt->mnt_parent); + do_attach_real_mnt(mnt); + if (delflag) { + list_del_init(&mnt->mnt_pnode_mntlist); + mnt->mnt_pnode = NULL; + SET_MNT_PRIVATE(mnt); + } + return 0; +} + +/* + * @pnode: walk the propogation tree and complete the + * attachments of the child mounts to the parents + * correspondingly. + * @flag: if set destroy the propogation tree + */ +int +pnode_real_mount(struct vfspnode *pnode, int flag) +{ + int ret=0,traversal; + struct vfsmount *slave_mnt, *member_mnt, *t_m; + struct pcontext context; + + context.start = pnode; + context.pnode = NULL; + while(pnode_next(&context)) { + traversal = context.traversal; + pnode = context.pnode; + if(traversal == PNODE_MID) { + if (flag) { + BUG_ON(!list_empty(&pnode->pnode_vfs)); + BUG_ON(!list_empty(&pnode->pnode_slavevfs)); + BUG_ON(!list_empty(&pnode->pnode_slavepnode)); + list_del_init(&pnode->pnode_peer_slave); + put_pnode(pnode); + } + } else if(traversal == PNODE_UP) { + // traverse member vfsmounts + spin_lock(&vfspnode_lock); + list_for_each_entry_safe(member_mnt, + t_m, &pnode->pnode_vfs, mnt_pnode_mntlist) { + spin_unlock(&vfspnode_lock); + if ((ret = vfs_real_mount_func(member_mnt, flag))) + goto out; + } + list_for_each_entry_safe(slave_mnt, + t_m, &pnode->pnode_slavevfs, mnt_pnode_mntlist) { + spin_unlock(&vfspnode_lock); + if ((ret = vfs_real_mount_func(slave_mnt, flag))) + goto out; + spin_lock(&vfspnode_lock); + } + spin_unlock(&vfspnode_lock); + } + } + +out: + return ret; +} Index: 2.6.12/include/linux/fs.h =================================================================== --- 2.6.12.orig/include/linux/fs.h +++ 2.6.12/include/linux/fs.h @@ -1216,7 +1216,11 @@ extern struct vfsmount *kern_mount(struc extern int may_umount_tree(struct vfsmount *); extern int may_umount(struct vfsmount *); extern long do_mount(char *, char *, char *, unsigned long, void *); +extern struct vfsmount *do_attach_prepare_mnt(struct vfsmount *, + struct dentry *, struct vfsmount *, int ); +extern void do_attach_real_mnt(struct vfsmount *); extern struct vfsmount *do_make_mounted(struct vfsmount *, struct dentry *); +extern int do_make_unmounted(struct vfsmount *); extern int vfs_statfs(struct super_block *, struct kstatfs *); Index: 2.6.12/include/linux/pnode.h =================================================================== --- 2.6.12.orig/include/linux/pnode.h +++ 2.6.12/include/linux/pnode.h @@ -73,6 +73,11 @@ void pnode_del_slave_mnt(struct vfsmount void pnode_del_member_mnt(struct vfsmount *); void pnode_disassociate_mnt(struct vfsmount *); void pnode_add_slave_pnode(struct vfspnode *, struct vfspnode *); +int pnode_merge_pnode(struct vfspnode *, struct vfspnode *); struct vfsmount * pnode_make_mounted(struct vfspnode *, struct vfsmount *, struct dentry *); +int pnode_make_unmounted(struct vfspnode *); +int pnode_prepare_mount(struct vfspnode *, struct vfspnode *, struct dentry *, + struct vfsmount *, struct vfsmount *); +int pnode_real_mount(struct vfspnode *, int); #endif /* KERNEL */ #endif /* _LINUX_PNODE_H */ Index: 2.6.12/include/linux/namespace.h =================================================================== --- 2.6.12.orig/include/linux/namespace.h +++ 2.6.12/include/linux/namespace.h @@ -9,7 +9,6 @@ struct namespace { atomic_t count; struct vfsmount * root; struct list_head list; - struct rw_semaphore sem; }; extern void umount_tree(struct vfsmount *); --=-00CL9+fUmHQGgsZyy2Am--