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

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
...@@ -1538,7 +1538,7 @@ static int do_remount(struct path *path, int flags, int mnt_flags, ...@@ -1538,7 +1538,7 @@ static int do_remount(struct path *path, int flags, int mnt_flags,
err = do_remount_sb(sb, flags, data, 0); err = do_remount_sb(sb, flags, data, 0);
if (!err) { if (!err) {
spin_lock(&vfsmount_lock); 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; path->mnt->mnt_flags = mnt_flags;
spin_unlock(&vfsmount_lock); spin_unlock(&vfsmount_lock);
} }
......
...@@ -25,7 +25,7 @@ ...@@ -25,7 +25,7 @@
static inline void set_mnt_shared(struct vfsmount *mnt) 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; mnt->mnt_flags |= MNT_SHARED;
} }
......
...@@ -34,7 +34,16 @@ struct mnt_namespace; ...@@ -34,7 +34,16 @@ struct mnt_namespace;
#define MNT_SHARED 0x1000 /* if the vfsmount is a shared mount */ #define MNT_SHARED 0x1000 /* if the vfsmount is a shared mount */
#define MNT_UNBINDABLE 0x2000 /* if the vfsmount is a unbindable 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 vfsmount {
struct list_head mnt_hash; struct list_head mnt_hash;
......
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