[RFC][PATCH 2/3] vfs: Add a function to lazily unmount all mounts from any dentry.

From: Eric W. Biederman
Date: Fri Oct 04 2013 - 18:43:35 EST



Signed-off-by: Eric W. Biederman <ebiederman@xxxxxxxxxxx>
---
fs/mount.h | 1 +
fs/namespace.c | 24 ++++++++++++++++++++++++
2 files changed, 25 insertions(+), 0 deletions(-)

diff --git a/fs/mount.h b/fs/mount.h
index e4342b8dfab1..7a6a2bb3f290 100644
--- a/fs/mount.h
+++ b/fs/mount.h
@@ -79,6 +79,7 @@ static inline int is_mounted(struct vfsmount *mnt)
}

extern struct mount *__lookup_mnt(struct vfsmount *, struct dentry *, int);
+extern void detach_mounts(struct dentry *dentry);

static inline void get_mnt_ns(struct mnt_namespace *ns)
{
diff --git a/fs/namespace.c b/fs/namespace.c
index d092964fe7f9..8eaee0c14fdb 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -1294,6 +1294,30 @@ static int do_umount(struct mount *mnt, int flags)
return retval;
}

+void detach_mounts(struct dentry *dentry)
+{
+ struct mount *mnt, *next;
+ struct mountpoint *mp;
+
+ namespace_lock();
+ if (!d_mountpoint(dentry)) {
+ namespace_unlock();
+ return;
+ }
+ mp = new_mountpoint(dentry);
+ if (IS_ERR(mp)) {
+ return;
+ }
+ br_write_lock(&vfsmount_lock);
+ list_for_each_entry_safe(mnt, next, &mp->m_list, mnt_mp_list) {
+ if (!list_empty(&mnt->mnt_list))
+ umount_tree(mnt, 1);
+ }
+ br_write_unlock(&vfsmount_lock);
+ put_mountpoint(mp);
+ namespace_unlock();
+}
+
/*
* Is the caller allowed to modify his namespace?
*/
--
1.7.5.4

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