diff options
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/namespace.c | 77 | ||||
| -rw-r--r-- | fs/pnode.c | 81 |
2 files changed, 121 insertions, 37 deletions
diff --git a/fs/namespace.c b/fs/namespace.c index 46f99bc585b..08967036370 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -227,8 +227,17 @@ static struct vfsmount *clone_mnt(struct vfsmount *old, struct dentry *root, mnt->mnt_mountpoint = mnt->mnt_root; mnt->mnt_parent = mnt; - if ((flag & CL_PROPAGATION) || IS_MNT_SHARED(old)) - list_add(&mnt->mnt_share, &old->mnt_share); + if (flag & CL_SLAVE) { + list_add(&mnt->mnt_slave, &old->mnt_slave_list); + mnt->mnt_master = old; + CLEAR_MNT_SHARED(mnt); + } else { + if ((flag & CL_PROPAGATION) || IS_MNT_SHARED(old)) + list_add(&mnt->mnt_share, &old->mnt_share); + if (IS_MNT_SLAVE(old)) + list_add(&mnt->mnt_slave, &old->mnt_slave); + mnt->mnt_master = old->mnt_master; + } if (flag & CL_MAKE_SHARED) set_mnt_shared(mnt); @@ -689,18 +698,18 @@ Enomem: * * NOTE: in the table below explains the semantics when a source mount * of a given type is attached to a destination mount of a given type. - * --------------------------------------------- - * | BIND MOUNT OPERATION | - * |******************************************** - * | source-->| shared | private | - * | dest | | | - * | | | | | - * | v | | | - * |******************************************** - * | shared | shared (++) | shared (+) | - * | | | | - * |non-shared| shared (+) | private | - * ********************************************* + * ------------------------------------------------------------- + * | BIND MOUNT OPERATION | + * |************************************************************* + * | source-->| shared | private | slave | + * | dest | | | | + * | | | | | | + * | v | | | | + * |************************************************************* + * | shared | shared (++) | shared (+) | shared(+++)| + * | | | | | + * |non-shared| shared (+) | private | slave (*) | + * ************************************************************** * A bind operation clones the source mount and mounts the clone on the * destination mount. * @@ -710,21 +719,33 @@ Enomem: * (+) the cloned mount is created under the destination mount and is marked * as shared. The cloned mount is added to the peer group of the source * mount. - * --------------------------------------------- - * | MOVE MOUNT OPERATION | - * |******************************************** - * | source-->| shared | private | - * | dest | | | - * | | | | | - * | v | | | - * |******************************************** - * | shared | shared (+) | shared (+) | - * | | | | - * |non-shared| shared (+*) | private | - * ********************************************* - * (+) the mount is moved to the destination. And is then propagated to all - * the mounts in the propagation tree of the destination mount. + * (+++) the mount is propagated to all the mounts in the propagation tree + * of the destination mount and the cloned mount is made slave + * of the same master as that of the source mount. The cloned mount + * is marked as 'shared and slave'. + * (*) the cloned mount is made a slave of the same master as that of the + * source mount. + * + * -------------------------------------------------------------- + * | MOVE MOUNT OPERATION | + * |************************************************************* + * | source-->| shared | private | slave | + * | dest | | | | + * | | | | | | + * | v | | | | + * |************************************************************* + * | shared | shared (+) | shared (+) | shared(+++) | + * | | | | | + * |non-shared| shared (+*) | private | slave (*) | + * ************************************************************** + * + * (+) the mount is moved to the destination. And is then propagated to + * all the mounts in the propagation tree of the destination mount. * (+*) the mount is moved to the destination. + * (+++) the mount is moved to the destination and is then propagated to + * all the mounts belonging to the destination mount's propagation tree. + * the mount is marked as 'shared and slave'. + * (*) the mount continues to be a slave at the new location. * * if the source mount is a tree, the operations explained above is * applied to each mount in the tree. diff --git a/fs/pnode.c b/fs/pnode.c index f73eba24f1d..3e266c5a307 100644 --- a/fs/pnode.c +++ b/fs/pnode.c @@ -17,6 +17,16 @@ static inline struct vfsmount *next_peer(struct vfsmount *p) return list_entry(p->mnt_share.next, struct vfsmount, mnt_share); } +static inline struct vfsmount *first_slave(struct vfsmount *p) +{ + return list_entry(p->mnt_slave_list.next, struct vfsmount, mnt_slave); +} + +static inline struct vfsmount *next_slave(struct vfsmount *p) +{ + return list_entry(p->mnt_slave.next, struct vfsmount, mnt_slave); +} + static int do_make_slave(struct vfsmount *mnt) { struct vfsmount *peer_mnt = mnt, *master = mnt->mnt_master; @@ -83,10 +93,64 @@ void change_mnt_propagation(struct vfsmount *mnt, int type) static struct vfsmount *propagation_next(struct vfsmount *m, struct vfsmount *origin) { - m = next_peer(m); - if (m == origin) - return NULL; - return m; + /* are there any slaves of this mount? */ + if (!IS_MNT_NEW(m) && !list_empty(&m->mnt_slave_list)) + return first_slave(m); + + while (1) { + struct vfsmount *next; + struct vfsmount *master = m->mnt_master; + + if ( master == origin->mnt_master ) { + next = next_peer(m); + return ((next == origin) ? NULL : next); + } else if (m->mnt_slave.next != &master->mnt_slave_list) + return next_slave(m); + + /* back at master */ + m = master; + } +} + +/* + * return the source mount to be used for cloning + * + * @dest the current destination mount + * @last_dest the last seen destination mount + * @last_src the last seen source mount + * @type return CL_SLAVE if the new mount has to be + * cloned as a slave. + */ +static struct vfsmount *get_source(struct vfsmount *dest, + struct vfsmount *last_dest, + struct vfsmount *last_src, + int *type) +{ + struct vfsmount *p_last_src = NULL; + struct vfsmount *p_last_dest = NULL; + *type = CL_PROPAGATION;; + + if (IS_MNT_SHARED(dest)) + *type |= CL_MAKE_SHARED; + + while (last_dest != dest->mnt_master) { + p_last_dest = last_dest; + p_last_src = last_src; + last_dest = last_dest->mnt_master; + last_src = last_src->mnt_master; + } + + if (p_last_dest) { + do { + p_last_dest = next_peer(p_last_dest); + } while (IS_MNT_NEW(p_last_dest)); + } + + if (dest != p_last_dest) { + *type |= CL_SLAVE; + return last_src; + } else + return p_last_src; } /* @@ -114,16 +178,15 @@ int propagate_mnt(struct vfsmount *dest_mnt, struct dentry *dest_dentry, for (m = propagation_next(dest_mnt, dest_mnt); m; m = propagation_next(m, dest_mnt)) { - int type = CL_PROPAGATION; + int type; + struct vfsmount *source; if (IS_MNT_NEW(m)) continue; - if (IS_MNT_SHARED(m)) - type |= CL_MAKE_SHARED; + source = get_source(m, prev_dest_mnt, prev_src_mnt, &type); - if (!(child = copy_tree(source_mnt, source_mnt->mnt_root, - type))) { + if (!(child = copy_tree(source, source->mnt_root, type))) { ret = -ENOMEM; list_splice(tree_list, tmp_list.prev); goto out; |