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authorAl Viro <viro@zeniv.linux.org.uk>2005-11-07 17:15:49 -0500
committerLinus Torvalds <torvalds@g5.osdl.org>2005-11-07 18:18:10 -0800
commit5addc5dd8836aa061f6efc4a0d9ba6323726297a (patch)
treea5ce3703bbb421c93482b6043ebd57137276808f /fs/namespace.c
parent1abe77b0fc4b485927f1f798ae81a752677e1d05 (diff)
downloadlinux-5addc5dd8836aa061f6efc4a0d9ba6323726297a.tar.bz2
[PATCH] make /proc/mounts pollable
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'fs/namespace.c')
-rw-r--r--fs/namespace.c30
1 files changed, 29 insertions, 1 deletions
diff --git a/fs/namespace.c b/fs/namespace.c
index 611f777bbd61..d1aca685aacf 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -37,7 +37,9 @@ static inline int sysfs_init(void)
#endif
/* spinlock for vfsmount related operations, inplace of dcache_lock */
- __cacheline_aligned_in_smp DEFINE_SPINLOCK(vfsmount_lock);
+__cacheline_aligned_in_smp DEFINE_SPINLOCK(vfsmount_lock);
+
+static int event;
static struct list_head *mount_hashtable;
static int hash_mask __read_mostly, hash_bits __read_mostly;
@@ -111,6 +113,22 @@ static inline int check_mnt(struct vfsmount *mnt)
return mnt->mnt_namespace == current->namespace;
}
+static void touch_namespace(struct namespace *ns)
+{
+ if (ns) {
+ ns->event = ++event;
+ wake_up_interruptible(&ns->poll);
+ }
+}
+
+static void __touch_namespace(struct namespace *ns)
+{
+ if (ns && ns->event != event) {
+ ns->event = event;
+ wake_up_interruptible(&ns->poll);
+ }
+}
+
static void detach_mnt(struct vfsmount *mnt, struct nameidata *old_nd)
{
old_nd->dentry = mnt->mnt_mountpoint;
@@ -384,6 +402,7 @@ static void umount_tree(struct vfsmount *mnt)
for (p = mnt; p; p = next_mnt(p, mnt)) {
list_del(&p->mnt_list);
list_add(&p->mnt_list, &kill);
+ __touch_namespace(p->mnt_namespace);
p->mnt_namespace = NULL;
}
@@ -473,6 +492,7 @@ static int do_umount(struct vfsmount *mnt, int flags)
down_write(&current->namespace->sem);
spin_lock(&vfsmount_lock);
+ event++;
retval = -EBUSY;
if (atomic_read(&mnt->mnt_count) == 2 || flags & MNT_DETACH) {
@@ -634,6 +654,7 @@ static int graft_tree(struct vfsmount *mnt, struct nameidata *nd)
list_splice(&head, current->namespace->list.prev);
mntget(mnt);
err = 0;
+ touch_namespace(current->namespace);
}
spin_unlock(&vfsmount_lock);
out_unlock:
@@ -771,6 +792,7 @@ static int do_move_mount(struct nameidata *nd, char *old_name)
detach_mnt(old_nd.mnt, &parent_nd);
attach_mnt(old_nd.mnt, nd);
+ touch_namespace(current->namespace);
/* if the mount is moved, it should no longer be expire
* automatically */
@@ -877,6 +899,7 @@ static void expire_mount(struct vfsmount *mnt, struct list_head *mounts)
struct nameidata old_nd;
/* delete from the namespace */
+ touch_namespace(mnt->mnt_namespace);
list_del_init(&mnt->mnt_list);
mnt->mnt_namespace = NULL;
detach_mnt(mnt, &old_nd);
@@ -1114,6 +1137,8 @@ int copy_namespace(int flags, struct task_struct *tsk)
atomic_set(&new_ns->count, 1);
init_rwsem(&new_ns->sem);
INIT_LIST_HEAD(&new_ns->list);
+ init_waitqueue_head(&new_ns->poll);
+ new_ns->event = 0;
down_write(&tsk->namespace->sem);
/* First pass: copy the tree topology */
@@ -1377,6 +1402,7 @@ asmlinkage long sys_pivot_root(const char __user *new_root, const char __user *p
detach_mnt(user_nd.mnt, &root_parent);
attach_mnt(user_nd.mnt, &old_nd); /* mount old root on put_old */
attach_mnt(new_nd.mnt, &root_parent); /* mount new_root on / */
+ touch_namespace(current->namespace);
spin_unlock(&vfsmount_lock);
chroot_fs_refs(&user_nd, &new_nd);
security_sb_post_pivotroot(&user_nd, &new_nd);
@@ -1413,6 +1439,8 @@ static void __init init_mount_tree(void)
atomic_set(&namespace->count, 1);
INIT_LIST_HEAD(&namespace->list);
init_rwsem(&namespace->sem);
+ init_waitqueue_head(&namespace->poll);
+ namespace->event = 0;
list_add(&mnt->mnt_list, &namespace->list);
namespace->root = mnt;
mnt->mnt_namespace = namespace;