Kill CL_PROPAGATION, sanitize fs/pnode.c:get_source()
First of all, get_source() never results in CL_PROPAGATION
alone. We either get CL_MAKE_SHARED (for the continuation
of peer group) or CL_SLAVE (slave that is not shared) or both
(beginning of peer group among slaves). Massage the code to
make that explicit, kill CL_PROPAGATION test in clone_mnt()
(nothing sets CL_MAKE_SHARED without CL_PROPAGATION and in
clone_mnt() we are checking CL_PROPAGATION after we'd found
that there's no CL_SLAVE, so the check for CL_MAKE_SHARED
would do just as well).
Fix comments, while we are at it...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/namespace.c b/fs/namespace.c
index c768f73..25c1dcf 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -573,7 +573,7 @@
mnt->mnt_master = old;
CLEAR_MNT_SHARED(mnt);
} else if (!(flag & CL_PRIVATE)) {
- if ((flag & CL_PROPAGATION) || IS_MNT_SHARED(old))
+ if ((flag & CL_MAKE_SHARED) || IS_MNT_SHARED(old))
list_add(&mnt->mnt_share, &old->mnt_share);
if (IS_MNT_SLAVE(old))
list_add(&mnt->mnt_slave, &old->mnt_slave);
diff --git a/fs/pnode.c b/fs/pnode.c
index 8d5f392..5cc564a 100644
--- a/fs/pnode.c
+++ b/fs/pnode.c
@@ -86,7 +86,7 @@
/*
* slave 'mnt' to a peer mount that has the
- * same root dentry. If none is available than
+ * same root dentry. If none is available then
* slave it to anything that is available.
*/
while ((peer_mnt = next_peer(peer_mnt)) != mnt &&
@@ -147,6 +147,11 @@
* get the next mount in the propagation tree.
* @m: the mount seen last
* @origin: the original mount from where the tree walk initiated
+ *
+ * Note that peer groups form contiguous segments of slave lists.
+ * We rely on that in get_source() to be able to find out if
+ * vfsmount found while iterating with propagation_next() is
+ * a peer of one we'd found earlier.
*/
static struct vfsmount *propagation_next(struct vfsmount *m,
struct vfsmount *origin)
@@ -186,10 +191,6 @@
{
struct vfsmount *p_last_src = NULL;
struct vfsmount *p_last_dest = NULL;
- *type = CL_PROPAGATION;
-
- if (IS_MNT_SHARED(dest))
- *type |= CL_MAKE_SHARED;
while (last_dest != dest->mnt_master) {
p_last_dest = last_dest;
@@ -202,13 +203,18 @@
do {
p_last_dest = next_peer(p_last_dest);
} while (IS_MNT_NEW(p_last_dest));
+ /* is that a peer of the earlier? */
+ if (dest == p_last_dest) {
+ *type = CL_MAKE_SHARED;
+ return p_last_src;
+ }
}
-
- if (dest != p_last_dest) {
- *type |= CL_SLAVE;
- return last_src;
- } else
- return p_last_src;
+ /* slave of the earlier, then */
+ *type = CL_SLAVE;
+ /* beginning of peer group among the slaves? */
+ if (IS_MNT_SHARED(dest))
+ *type |= CL_MAKE_SHARED;
+ return last_src;
}
/*
diff --git a/fs/pnode.h b/fs/pnode.h
index 958665d..6c7ef32 100644
--- a/fs/pnode.h
+++ b/fs/pnode.h
@@ -21,8 +21,7 @@
#define CL_SLAVE 0x02
#define CL_COPY_ALL 0x04
#define CL_MAKE_SHARED 0x08
-#define CL_PROPAGATION 0x10
-#define CL_PRIVATE 0x20
+#define CL_PRIVATE 0x10
static inline void set_mnt_shared(struct vfsmount *mnt)
{