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vfs: now it can be done - make mnt_parent point to struct mount

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Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2011-11-24 22:19:58 -05:00
parent 3376f34fff
commit 0714a53380
5 changed files with 53 additions and 50 deletions
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7
fs/dcache.c
View file

@ -2452,6 +2452,7 @@ static int prepend_path(const struct path *path,
{ {
struct dentry *dentry = path->dentry; struct dentry *dentry = path->dentry;
struct vfsmount *vfsmnt = path->mnt; struct vfsmount *vfsmnt = path->mnt;
struct mount *mnt = real_mount(vfsmnt);
bool slash = false; bool slash = false;
int error = 0; int error = 0;
@ -2460,12 +2461,12 @@ static int prepend_path(const struct path *path,
struct dentry * parent; struct dentry * parent;
if (dentry == vfsmnt->mnt_root || IS_ROOT(dentry)) { if (dentry == vfsmnt->mnt_root || IS_ROOT(dentry)) {
struct mount *mnt = real_mount(vfsmnt);
/* Global root? */ /* Global root? */
if (!mnt_has_parent(mnt)) if (!mnt_has_parent(mnt))
goto global_root; goto global_root;
dentry = vfsmnt->mnt_mountpoint; dentry = mnt->mnt.mnt_mountpoint;
vfsmnt = mnt->mnt_parent; mnt = mnt->mnt_parent;
vfsmnt = &mnt->mnt;
continue; continue;
} }
parent = dentry->d_parent; parent = dentry->d_parent;

4
fs/mount.h
View file

@ -2,7 +2,7 @@
struct mount { struct mount {
struct list_head mnt_hash; struct list_head mnt_hash;
struct vfsmount *mnt_parent; struct mount *mnt_parent;
struct vfsmount mnt; struct vfsmount mnt;
}; };
@ -13,7 +13,7 @@ static inline struct mount *real_mount(struct vfsmount *mnt)
static inline int mnt_has_parent(struct mount *mnt) static inline int mnt_has_parent(struct mount *mnt)
{ {
return &mnt->mnt != mnt->mnt_parent; return mnt != mnt->mnt_parent;
} }
extern struct mount *__lookup_mnt(struct vfsmount *, struct dentry *, int); extern struct mount *__lookup_mnt(struct vfsmount *, struct dentry *, int);

24
fs/namei.c
View file

@ -677,36 +677,38 @@ follow_link(struct path *link, struct nameidata *nd, void **p)
static int follow_up_rcu(struct path *path) static int follow_up_rcu(struct path *path)
{ {
struct vfsmount *parent; struct mount *mnt = real_mount(path->mnt);
struct mount *parent;
struct dentry *mountpoint; struct dentry *mountpoint;
parent = real_mount(path->mnt)->mnt_parent; parent = mnt->mnt_parent;
if (parent == path->mnt) if (&parent->mnt == path->mnt)
return 0; return 0;
mountpoint = path->mnt->mnt_mountpoint; mountpoint = mnt->mnt.mnt_mountpoint;
path->dentry = mountpoint; path->dentry = mountpoint;
path->mnt = parent; path->mnt = &parent->mnt;
return 1; return 1;
} }
int follow_up(struct path *path) int follow_up(struct path *path)
{ {
struct vfsmount *parent; struct mount *mnt = real_mount(path->mnt);
struct mount *parent;
struct dentry *mountpoint; struct dentry *mountpoint;
br_read_lock(vfsmount_lock); br_read_lock(vfsmount_lock);
parent = real_mount(path->mnt)->mnt_parent; parent = mnt->mnt_parent;
if (parent == path->mnt) { if (&parent->mnt == path->mnt) {
br_read_unlock(vfsmount_lock); br_read_unlock(vfsmount_lock);
return 0; return 0;
} }
mntget(parent); mntget(&parent->mnt);
mountpoint = dget(path->mnt->mnt_mountpoint); mountpoint = dget(mnt->mnt.mnt_mountpoint);
br_read_unlock(vfsmount_lock); br_read_unlock(vfsmount_lock);
dput(path->dentry); dput(path->dentry);
path->dentry = mountpoint; path->dentry = mountpoint;
mntput(path->mnt); mntput(path->mnt);
path->mnt = parent; path->mnt = &parent->mnt;
return 1; return 1;
} }

52
fs/namespace.c
View file

@ -476,7 +476,7 @@ struct mount *__lookup_mnt(struct vfsmount *mnt, struct dentry *dentry,
if (tmp == head) if (tmp == head)
break; break;
p = list_entry(tmp, struct mount, mnt_hash); p = list_entry(tmp, struct mount, mnt_hash);
if (p->mnt_parent == mnt && p->mnt.mnt_mountpoint == dentry) { if (&p->mnt_parent->mnt == mnt && p->mnt.mnt_mountpoint == dentry) {
found = p; found = p;
break; break;
} }
@ -558,8 +558,8 @@ static void dentry_reset_mounted(struct dentry *dentry)
static void detach_mnt(struct mount *mnt, struct path *old_path) static void detach_mnt(struct mount *mnt, struct path *old_path)
{ {
old_path->dentry = mnt->mnt.mnt_mountpoint; old_path->dentry = mnt->mnt.mnt_mountpoint;
old_path->mnt = mnt->mnt_parent; old_path->mnt = &mnt->mnt_parent->mnt;
mnt->mnt_parent = &mnt->mnt; mnt->mnt_parent = mnt;
mnt->mnt.mnt_mountpoint = mnt->mnt.mnt_root; mnt->mnt.mnt_mountpoint = mnt->mnt.mnt_root;
list_del_init(&mnt->mnt.mnt_child); list_del_init(&mnt->mnt.mnt_child);
list_del_init(&mnt->mnt_hash); list_del_init(&mnt->mnt_hash);
@ -572,7 +572,7 @@ static void detach_mnt(struct mount *mnt, struct path *old_path)
void mnt_set_mountpoint(struct vfsmount *mnt, struct dentry *dentry, void mnt_set_mountpoint(struct vfsmount *mnt, struct dentry *dentry,
struct mount *child_mnt) struct mount *child_mnt)
{ {
child_mnt->mnt_parent = mntget(mnt); child_mnt->mnt_parent = real_mount(mntget(mnt));
child_mnt->mnt.mnt_mountpoint = dget(dentry); child_mnt->mnt.mnt_mountpoint = dget(dentry);
spin_lock(&dentry->d_lock); spin_lock(&dentry->d_lock);
dentry->d_flags |= DCACHE_MOUNTED; dentry->d_flags |= DCACHE_MOUNTED;
@ -610,12 +610,12 @@ static inline void __mnt_make_shortterm(struct vfsmount *mnt)
*/ */
static void commit_tree(struct mount *mnt) static void commit_tree(struct mount *mnt)
{ {
struct vfsmount *parent = mnt->mnt_parent; struct mount *parent = mnt->mnt_parent;
struct vfsmount *m; struct vfsmount *m;
LIST_HEAD(head); LIST_HEAD(head);
struct mnt_namespace *n = parent->mnt_ns; struct mnt_namespace *n = parent->mnt.mnt_ns;
BUG_ON(parent == &mnt->mnt); BUG_ON(parent == mnt);
list_add_tail(&head, &mnt->mnt.mnt_list); list_add_tail(&head, &mnt->mnt.mnt_list);
list_for_each_entry(m, &head, mnt_list) { list_for_each_entry(m, &head, mnt_list) {
@ -626,8 +626,8 @@ static void commit_tree(struct mount *mnt)
list_splice(&head, n->list.prev); list_splice(&head, n->list.prev);
list_add_tail(&mnt->mnt_hash, mount_hashtable + list_add_tail(&mnt->mnt_hash, mount_hashtable +
hash(parent, mnt->mnt.mnt_mountpoint)); hash(&parent->mnt, mnt->mnt.mnt_mountpoint));
list_add_tail(&mnt->mnt.mnt_child, &parent->mnt_mounts); list_add_tail(&mnt->mnt.mnt_child, &parent->mnt.mnt_mounts);
touch_mnt_namespace(n); touch_mnt_namespace(n);
} }
@ -639,9 +639,9 @@ static struct mount *next_mnt(struct mount *p, struct vfsmount *root)
if (&p->mnt == root) if (&p->mnt == root)
return NULL; return NULL;
next = p->mnt.mnt_child.next; next = p->mnt.mnt_child.next;
if (next != &p->mnt_parent->mnt_mounts) if (next != &p->mnt_parent->mnt.mnt_mounts)
break; break;
p = real_mount(p->mnt_parent); p = p->mnt_parent;
} }
} }
return list_entry(next, struct mount, mnt.mnt_child); return list_entry(next, struct mount, mnt.mnt_child);
@ -682,7 +682,7 @@ vfs_kern_mount(struct file_system_type *type, int flags, const char *name, void
mnt->mnt.mnt_root = root; mnt->mnt.mnt_root = root;
mnt->mnt.mnt_sb = root->d_sb; mnt->mnt.mnt_sb = root->d_sb;
mnt->mnt.mnt_mountpoint = mnt->mnt.mnt_root; mnt->mnt.mnt_mountpoint = mnt->mnt.mnt_root;
mnt->mnt_parent = &mnt->mnt; mnt->mnt_parent = mnt;
return &mnt->mnt; return &mnt->mnt;
} }
EXPORT_SYMBOL_GPL(vfs_kern_mount); EXPORT_SYMBOL_GPL(vfs_kern_mount);
@ -710,7 +710,7 @@ static struct mount *clone_mnt(struct mount *old, struct dentry *root,
mnt->mnt.mnt_sb = sb; mnt->mnt.mnt_sb = sb;
mnt->mnt.mnt_root = dget(root); mnt->mnt.mnt_root = dget(root);
mnt->mnt.mnt_mountpoint = mnt->mnt.mnt_root; mnt->mnt.mnt_mountpoint = mnt->mnt.mnt_root;
mnt->mnt_parent = &mnt->mnt; mnt->mnt_parent = mnt;
if (flag & CL_SLAVE) { if (flag & CL_SLAVE) {
list_add(&mnt->mnt.mnt_slave, &old->mnt.mnt_slave_list); list_add(&mnt->mnt.mnt_slave, &old->mnt.mnt_slave_list);
@ -1027,7 +1027,7 @@ static int show_mountinfo(struct seq_file *m, void *v)
struct path root = p->root; struct path root = p->root;
int err = 0; int err = 0;
seq_printf(m, "%i %i %u:%u ", mnt->mnt_id, r->mnt_parent->mnt_id, seq_printf(m, "%i %i %u:%u ", mnt->mnt_id, r->mnt_parent->mnt.mnt_id,
MAJOR(sb->s_dev), MINOR(sb->s_dev)); MAJOR(sb->s_dev), MINOR(sb->s_dev));
if (sb->s_op->show_path) if (sb->s_op->show_path)
err = sb->s_op->show_path(m, mnt); err = sb->s_op->show_path(m, mnt);
@ -1202,9 +1202,9 @@ void release_mounts(struct list_head *head)
br_write_lock(vfsmount_lock); br_write_lock(vfsmount_lock);
dentry = mnt->mnt.mnt_mountpoint; dentry = mnt->mnt.mnt_mountpoint;
m = mnt->mnt_parent; m = &mnt->mnt_parent->mnt;
mnt->mnt.mnt_mountpoint = mnt->mnt.mnt_root; mnt->mnt.mnt_mountpoint = mnt->mnt.mnt_root;
mnt->mnt_parent = &mnt->mnt; mnt->mnt_parent = mnt;
m->mnt_ghosts--; m->mnt_ghosts--;
br_write_unlock(vfsmount_lock); br_write_unlock(vfsmount_lock);
dput(dentry); dput(dentry);
@ -1237,7 +1237,7 @@ void umount_tree(struct mount *mnt, int propagate, struct list_head *kill)
__mnt_make_shortterm(&p->mnt); __mnt_make_shortterm(&p->mnt);
list_del_init(&p->mnt.mnt_child); list_del_init(&p->mnt.mnt_child);
if (mnt_has_parent(p)) { if (mnt_has_parent(p)) {
p->mnt_parent->mnt_ghosts++; p->mnt_parent->mnt.mnt_ghosts++;
dentry_reset_mounted(p->mnt.mnt_mountpoint); dentry_reset_mounted(p->mnt.mnt_mountpoint);
} }
change_mnt_propagation(p, MS_PRIVATE); change_mnt_propagation(p, MS_PRIVATE);
@ -1435,9 +1435,9 @@ struct mount *copy_tree(struct mount *mnt, struct dentry *dentry,
s = skip_mnt_tree(s); s = skip_mnt_tree(s);
continue; continue;
} }
while (p != real_mount(s->mnt_parent)) { while (p != s->mnt_parent) {
p = real_mount(p->mnt_parent); p = p->mnt_parent;
q = real_mount(q->mnt_parent); q = q->mnt_parent;
} }
p = s; p = s;
path.mnt = &q->mnt; path.mnt = &q->mnt;
@ -1899,7 +1899,7 @@ static int do_move_mount(struct path *path, char *old_name)
/* /*
* Don't move a mount residing in a shared parent. * Don't move a mount residing in a shared parent.
*/ */
if (IS_MNT_SHARED(old->mnt_parent)) if (IS_MNT_SHARED(&old->mnt_parent->mnt))
goto out1; goto out1;
/* /*
* Don't move a mount tree containing unbindable mounts to a destination * Don't move a mount tree containing unbindable mounts to a destination
@ -1909,7 +1909,7 @@ static int do_move_mount(struct path *path, char *old_name)
tree_contains_unbindable(old)) tree_contains_unbindable(old))
goto out1; goto out1;
err = -ELOOP; err = -ELOOP;
for (p = real_mount(path->mnt); mnt_has_parent(p); p = real_mount(p->mnt_parent)) for (p = real_mount(path->mnt); mnt_has_parent(p); p = p->mnt_parent)
if (p == old) if (p == old)
goto out1; goto out1;
@ -2159,7 +2159,7 @@ static int select_submounts(struct mount *parent, struct list_head *graveyard)
*/ */
if (this_parent != parent) { if (this_parent != parent) {
next = this_parent->mnt.mnt_child.next; next = this_parent->mnt.mnt_child.next;
this_parent = real_mount(this_parent->mnt_parent); this_parent = this_parent->mnt_parent;
goto resume; goto resume;
} }
return found; return found;
@ -2565,7 +2565,7 @@ bool is_path_reachable(struct mount *mnt, struct dentry *dentry,
{ {
while (&mnt->mnt != root->mnt && mnt_has_parent(mnt)) { while (&mnt->mnt != root->mnt && mnt_has_parent(mnt)) {
dentry = mnt->mnt.mnt_mountpoint; dentry = mnt->mnt.mnt_mountpoint;
mnt = real_mount(mnt->mnt_parent); mnt = mnt->mnt_parent;
} }
return &mnt->mnt == root->mnt && is_subdir(dentry, root->dentry); return &mnt->mnt == root->mnt && is_subdir(dentry, root->dentry);
} }
@ -2636,8 +2636,8 @@ SYSCALL_DEFINE2(pivot_root, const char __user *, new_root,
new_mnt = real_mount(new.mnt); new_mnt = real_mount(new.mnt);
root_mnt = real_mount(root.mnt); root_mnt = real_mount(root.mnt);
if (IS_MNT_SHARED(old.mnt) || if (IS_MNT_SHARED(old.mnt) ||
IS_MNT_SHARED(new_mnt->mnt_parent) || IS_MNT_SHARED(&new_mnt->mnt_parent->mnt) ||
IS_MNT_SHARED(root_mnt->mnt_parent)) IS_MNT_SHARED(&root_mnt->mnt_parent->mnt))
goto out4; goto out4;
if (!check_mnt(root.mnt) || !check_mnt(new.mnt)) if (!check_mnt(root.mnt) || !check_mnt(new.mnt))
goto out4; goto out4;

16
fs/pnode.c
View file

@ -292,10 +292,10 @@ int propagate_mount_busy(struct mount *mnt, int refcnt)
{ {
struct vfsmount *m; struct vfsmount *m;
struct mount *child; struct mount *child;
struct vfsmount *parent = mnt->mnt_parent; struct mount *parent = mnt->mnt_parent;
int ret = 0; int ret = 0;
if (&mnt->mnt == parent) if (mnt == parent)
return do_refcount_check(mnt, refcnt); return do_refcount_check(mnt, refcnt);
/* /*
@ -306,8 +306,8 @@ int propagate_mount_busy(struct mount *mnt, int refcnt)
if (!list_empty(&mnt->mnt.mnt_mounts) || do_refcount_check(mnt, refcnt)) if (!list_empty(&mnt->mnt.mnt_mounts) || do_refcount_check(mnt, refcnt))
return 1; return 1;
for (m = propagation_next(parent, parent); m; for (m = propagation_next(&parent->mnt, &parent->mnt); m;
m = propagation_next(m, parent)) { m = propagation_next(m, &parent->mnt)) {
child = __lookup_mnt(m, mnt->mnt.mnt_mountpoint, 0); child = __lookup_mnt(m, mnt->mnt.mnt_mountpoint, 0);
if (child && list_empty(&child->mnt.mnt_mounts) && if (child && list_empty(&child->mnt.mnt_mounts) &&
(ret = do_refcount_check(child, 1))) (ret = do_refcount_check(child, 1)))
@ -322,13 +322,13 @@ int propagate_mount_busy(struct mount *mnt, int refcnt)
*/ */
static void __propagate_umount(struct mount *mnt) static void __propagate_umount(struct mount *mnt)
{ {
struct vfsmount *parent = mnt->mnt_parent; struct mount *parent = mnt->mnt_parent;
struct vfsmount *m; struct vfsmount *m;
BUG_ON(parent == &mnt->mnt); BUG_ON(parent == mnt);
for (m = propagation_next(parent, parent); m; for (m = propagation_next(&parent->mnt, &parent->mnt); m;
m = propagation_next(m, parent)) { m = propagation_next(m, &parent->mnt)) {
struct mount *child = __lookup_mnt(m, struct mount *child = __lookup_mnt(m,
mnt->mnt.mnt_mountpoint, 0); mnt->mnt.mnt_mountpoint, 0);