Commit 495d6c9c authored by Valerie Aurora's avatar Valerie Aurora Committed by Al Viro
Browse files

VFS: Clean up shared mount flag propagation 



The handling of mount flags in set_mnt_shared() got a little tangled
up during previous cleanups, with the following problems:

* MNT_PNODE_MASK is defined as a literal constant when it should be a
bitwise xor of other MNT_* flags
* set_mnt_shared() clears and then sets MNT_SHARED (part of MNT_PNODE_MASK)
* MNT_PNODE_MASK could use a comment in mount.h
* MNT_PNODE_MASK is a terrible name, change to MNT_SHARED_MASK

This patch fixes these problems.

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 2ecdc82e

fs/namespace.c

+1 −1
Original line number Diff line number Diff line
@@ -1538,7 +1538,7 @@ static int do_remount(struct path *path, int flags, int mnt_flags, 
		err = do_remount_sb(sb, flags, data, 0);

	if (!err) {

		spin_lock(&vfsmount_lock);

		mnt_flags |= path->mnt->mnt_flags & MNT_PNODE_MASK;

		mnt_flags |= path->mnt->mnt_flags & MNT_PROPAGATION_MASK;

		path->mnt->mnt_flags = mnt_flags;

		spin_unlock(&vfsmount_lock);

	}

fs/pnode.h

+1 −1
Original line number Diff line number Diff line
@@ -25,7 +25,7 @@ 


static inline void set_mnt_shared(struct vfsmount *mnt)

{

	mnt->mnt_flags &= ~MNT_PNODE_MASK;

	mnt->mnt_flags &= ~MNT_SHARED_MASK;

	mnt->mnt_flags |= MNT_SHARED;

}

include/linux/mount.h

+10 −1
Original line number Diff line number Diff line
@@ -34,7 +34,16 @@ struct mnt_namespace; 


#define MNT_SHARED	0x1000	/* if the vfsmount is a shared mount */

#define MNT_UNBINDABLE	0x2000	/* if the vfsmount is a unbindable mount */

#define MNT_PNODE_MASK	0x3000	/* propagation flag mask */

/*

 * MNT_SHARED_MASK is the set of flags that should be cleared when a

 * mount becomes shared.  Currently, this is only the flag that says a

 * mount cannot be bind mounted, since this is how we create a mount

 * that shares events with another mount.  If you add a new MNT_*

 * flag, consider how it interacts with shared mounts.

 */

#define MNT_SHARED_MASK	(MNT_UNBINDABLE)

#define MNT_PROPAGATION_MASK	(MNT_SHARED | MNT_UNBINDABLE)





struct vfsmount {

	struct list_head mnt_hash;

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