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authorAl Viro <viro@zeniv.linux.org.uk>2007-06-07 12:20:32 -0400
committerAl Viro <viro@zeniv.linux.org.uk>2007-10-21 02:37:25 -0400
commit8aec08094570562bc305df33b088926d983c3540 (patch)
tree399f4590f81428d1f72d754d336da13c449120f9
parent5a190ae69766da9a34bf31200c5cea4c0667cf94 (diff)
[PATCH] new helpers - collect_mounts() and release_collected_mounts()
Get a snapshot of a subtree, creating private clones of vfsmounts for all its components and release such snapshot resp. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
-rw-r--r--fs/namespace.c22
-rw-r--r--fs/pnode.h1
-rw-r--r--include/linux/fs.h2
3 files changed, 24 insertions, 1 deletions
diff --git a/fs/namespace.c b/fs/namespace.c
index 860752998fb3..06083885b21e 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -246,7 +246,7 @@ static struct vfsmount *clone_mnt(struct vfsmount *old, struct dentry *root,
list_add(&mnt->mnt_slave, &old->mnt_slave_list);
mnt->mnt_master = old;
CLEAR_MNT_SHARED(mnt);
- } else {
+ } else if (!(flag & CL_PRIVATE)) {
if ((flag & CL_PROPAGATION) || IS_MNT_SHARED(old))
list_add(&mnt->mnt_share, &old->mnt_share);
if (IS_MNT_SLAVE(old))
@@ -746,6 +746,26 @@ Enomem:
return NULL;
}
+struct vfsmount *collect_mounts(struct vfsmount *mnt, struct dentry *dentry)
+{
+ struct vfsmount *tree;
+ down_read(&namespace_sem);
+ tree = copy_tree(mnt, dentry, CL_COPY_ALL | CL_PRIVATE);
+ up_read(&namespace_sem);
+ return tree;
+}
+
+void drop_collected_mounts(struct vfsmount *mnt)
+{
+ LIST_HEAD(umount_list);
+ down_read(&namespace_sem);
+ spin_lock(&vfsmount_lock);
+ umount_tree(mnt, 0, &umount_list);
+ spin_unlock(&vfsmount_lock);
+ up_read(&namespace_sem);
+ release_mounts(&umount_list);
+}
+
/*
* @source_mnt : mount tree to be attached
* @nd : place the mount tree @source_mnt is attached
diff --git a/fs/pnode.h b/fs/pnode.h
index d45bd8ec36bf..f249be2fee7a 100644
--- a/fs/pnode.h
+++ b/fs/pnode.h
@@ -22,6 +22,7 @@
#define CL_COPY_ALL 0x04
#define CL_MAKE_SHARED 0x08
#define CL_PROPAGATION 0x10
+#define CL_PRIVATE 0x20
static inline void set_mnt_shared(struct vfsmount *mnt)
{
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 1bcce660cf03..50078bb30a1c 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1470,6 +1470,8 @@ extern long do_mount(char *, char *, char *, unsigned long, void *);
extern struct vfsmount *copy_tree(struct vfsmount *, struct dentry *, int);
extern void mnt_set_mountpoint(struct vfsmount *, struct dentry *,
struct vfsmount *);
+extern struct vfsmount *collect_mounts(struct vfsmount *, struct dentry *);
+extern void drop_collected_mounts(struct vfsmount *);
extern int vfs_statfs(struct dentry *, struct kstatfs *);