Commit 7c4b93d8 authored by Al Viro's avatar Al Viro

[PATCH] count ghost references to vfsmounts

make propagate_mount_busy() exclude references from the vfsmounts
that had been isolated by umount_tree() and are just waiting for
release_mounts() to dispose of their ->mnt_parent/->mnt_mountpoint.
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 1a390689
...@@ -548,6 +548,7 @@ void release_mounts(struct list_head *head) ...@@ -548,6 +548,7 @@ void release_mounts(struct list_head *head)
m = mnt->mnt_parent; m = mnt->mnt_parent;
mnt->mnt_mountpoint = mnt->mnt_root; mnt->mnt_mountpoint = mnt->mnt_root;
mnt->mnt_parent = mnt; mnt->mnt_parent = mnt;
m->mnt_ghosts--;
spin_unlock(&vfsmount_lock); spin_unlock(&vfsmount_lock);
dput(dentry); dput(dentry);
mntput(m); mntput(m);
...@@ -572,8 +573,10 @@ void umount_tree(struct vfsmount *mnt, int propagate, struct list_head *kill) ...@@ -572,8 +573,10 @@ void umount_tree(struct vfsmount *mnt, int propagate, struct list_head *kill)
__touch_mnt_namespace(p->mnt_ns); __touch_mnt_namespace(p->mnt_ns);
p->mnt_ns = NULL; p->mnt_ns = NULL;
list_del_init(&p->mnt_child); list_del_init(&p->mnt_child);
if (p->mnt_parent != p) if (p->mnt_parent != p) {
p->mnt_parent->mnt_ghosts++;
p->mnt_mountpoint->d_mounted--; p->mnt_mountpoint->d_mounted--;
}
change_mnt_propagation(p, MS_PRIVATE); change_mnt_propagation(p, MS_PRIVATE);
} }
} }
......
...@@ -225,7 +225,7 @@ int propagate_mnt(struct vfsmount *dest_mnt, struct dentry *dest_dentry, ...@@ -225,7 +225,7 @@ int propagate_mnt(struct vfsmount *dest_mnt, struct dentry *dest_dentry,
*/ */
static inline int do_refcount_check(struct vfsmount *mnt, int count) static inline int do_refcount_check(struct vfsmount *mnt, int count)
{ {
int mycount = atomic_read(&mnt->mnt_count); int mycount = atomic_read(&mnt->mnt_count) - mnt->mnt_ghosts;
return (mycount > count); return (mycount > count);
} }
......
...@@ -61,6 +61,7 @@ struct vfsmount { ...@@ -61,6 +61,7 @@ struct vfsmount {
atomic_t mnt_count; atomic_t mnt_count;
int mnt_expiry_mark; /* true if marked for expiry */ int mnt_expiry_mark; /* true if marked for expiry */
int mnt_pinned; int mnt_pinned;
int mnt_ghosts;
}; };
static inline struct vfsmount *mntget(struct vfsmount *mnt) static inline struct vfsmount *mntget(struct vfsmount *mnt)
......
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