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authorRam Pai <linuxram@us.ibm.com>2005-11-07 17:21:01 -0500
committerLinus Torvalds <torvalds@g5.osdl.org>2005-11-07 18:18:11 -0800
commit5afe00221389998a25d611dc7941c06580c29eb6 (patch)
tree521270fb5974b42ac2b27666541f20fd375d8f66 /fs/pnode.c
parenta58b0eb8e64b78d9315a5491955e78b1391d42e5 (diff)
downloadlinux-linaro-5afe00221389998a25d611dc7941c06580c29eb6.tar.gz
[PATCH] handling of slave mounts
This makes bind, rbind, move, clone namespace and umount operations aware of the semantics of slave mount (see Documentation/sharedsubtree.txt in the last patch of the series for detailed description). Signed-off-by: Ram Pai <linuxram@us.ibm.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'fs/pnode.c')
-rw-r--r--fs/pnode.c81
1 files changed, 72 insertions, 9 deletions
diff --git a/fs/pnode.c b/fs/pnode.c
index f73eba24f1d..3e266c5a307 100644
--- a/fs/pnode.c
+++ b/fs/pnode.c
@@ -17,6 +17,16 @@ static inline struct vfsmount *next_peer(struct vfsmount *p)
return list_entry(p->mnt_share.next, struct vfsmount, mnt_share);
}
+static inline struct vfsmount *first_slave(struct vfsmount *p)
+{
+ return list_entry(p->mnt_slave_list.next, struct vfsmount, mnt_slave);
+}
+
+static inline struct vfsmount *next_slave(struct vfsmount *p)
+{
+ return list_entry(p->mnt_slave.next, struct vfsmount, mnt_slave);
+}
+
static int do_make_slave(struct vfsmount *mnt)
{
struct vfsmount *peer_mnt = mnt, *master = mnt->mnt_master;
@@ -83,10 +93,64 @@ void change_mnt_propagation(struct vfsmount *mnt, int type)
static struct vfsmount *propagation_next(struct vfsmount *m,
struct vfsmount *origin)
{
- m = next_peer(m);
- if (m == origin)
- return NULL;
- return m;
+ /* are there any slaves of this mount? */
+ if (!IS_MNT_NEW(m) && !list_empty(&m->mnt_slave_list))
+ return first_slave(m);
+
+ while (1) {
+ struct vfsmount *next;
+ struct vfsmount *master = m->mnt_master;
+
+ if ( master == origin->mnt_master ) {
+ next = next_peer(m);
+ return ((next == origin) ? NULL : next);
+ } else if (m->mnt_slave.next != &master->mnt_slave_list)
+ return next_slave(m);
+
+ /* back at master */
+ m = master;
+ }
+}
+
+/*
+ * return the source mount to be used for cloning
+ *
+ * @dest the current destination mount
+ * @last_dest the last seen destination mount
+ * @last_src the last seen source mount
+ * @type return CL_SLAVE if the new mount has to be
+ * cloned as a slave.
+ */
+static struct vfsmount *get_source(struct vfsmount *dest,
+ struct vfsmount *last_dest,
+ struct vfsmount *last_src,
+ int *type)
+{
+ 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;
+ p_last_src = last_src;
+ last_dest = last_dest->mnt_master;
+ last_src = last_src->mnt_master;
+ }
+
+ if (p_last_dest) {
+ do {
+ p_last_dest = next_peer(p_last_dest);
+ } while (IS_MNT_NEW(p_last_dest));
+ }
+
+ if (dest != p_last_dest) {
+ *type |= CL_SLAVE;
+ return last_src;
+ } else
+ return p_last_src;
}
/*
@@ -114,16 +178,15 @@ int propagate_mnt(struct vfsmount *dest_mnt, struct dentry *dest_dentry,
for (m = propagation_next(dest_mnt, dest_mnt); m;
m = propagation_next(m, dest_mnt)) {
- int type = CL_PROPAGATION;
+ int type;
+ struct vfsmount *source;
if (IS_MNT_NEW(m))
continue;
- if (IS_MNT_SHARED(m))
- type |= CL_MAKE_SHARED;
+ source = get_source(m, prev_dest_mnt, prev_src_mnt, &type);
- if (!(child = copy_tree(source_mnt, source_mnt->mnt_root,
- type))) {
+ if (!(child = copy_tree(source, source->mnt_root, type))) {
ret = -ENOMEM;
list_splice(tree_list, tmp_list.prev);
goto out;