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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/namespace.c
parenta58b0eb8e64b78d9315a5491955e78b1391d42e5 (diff)
downloadlwn-5afe00221389998a25d611dc7941c06580c29eb6.tar.gz
lwn-5afe00221389998a25d611dc7941c06580c29eb6.zip
[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/namespace.c')
-rw-r--r--fs/namespace.c77
1 files changed, 49 insertions, 28 deletions
diff --git a/fs/namespace.c b/fs/namespace.c
index 46f99bc585bd..089670363704 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -227,8 +227,17 @@ static struct vfsmount *clone_mnt(struct vfsmount *old, struct dentry *root,
mnt->mnt_mountpoint = mnt->mnt_root;
mnt->mnt_parent = mnt;
- if ((flag & CL_PROPAGATION) || IS_MNT_SHARED(old))
- list_add(&mnt->mnt_share, &old->mnt_share);
+ if (flag & CL_SLAVE) {
+ list_add(&mnt->mnt_slave, &old->mnt_slave_list);
+ mnt->mnt_master = old;
+ CLEAR_MNT_SHARED(mnt);
+ } else {
+ if ((flag & CL_PROPAGATION) || 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);
+ mnt->mnt_master = old->mnt_master;
+ }
if (flag & CL_MAKE_SHARED)
set_mnt_shared(mnt);
@@ -689,18 +698,18 @@ Enomem:
*
* NOTE: in the table below explains the semantics when a source mount
* of a given type is attached to a destination mount of a given type.
- * ---------------------------------------------
- * | BIND MOUNT OPERATION |
- * |********************************************
- * | source-->| shared | private |
- * | dest | | |
- * | | | | |
- * | v | | |
- * |********************************************
- * | shared | shared (++) | shared (+) |
- * | | | |
- * |non-shared| shared (+) | private |
- * *********************************************
+ * -------------------------------------------------------------
+ * | BIND MOUNT OPERATION |
+ * |*************************************************************
+ * | source-->| shared | private | slave |
+ * | dest | | | |
+ * | | | | | |
+ * | v | | | |
+ * |*************************************************************
+ * | shared | shared (++) | shared (+) | shared(+++)|
+ * | | | | |
+ * |non-shared| shared (+) | private | slave (*) |
+ * **************************************************************
* A bind operation clones the source mount and mounts the clone on the
* destination mount.
*
@@ -710,21 +719,33 @@ Enomem:
* (+) the cloned mount is created under the destination mount and is marked
* as shared. The cloned mount is added to the peer group of the source
* mount.
- * ---------------------------------------------
- * | MOVE MOUNT OPERATION |
- * |********************************************
- * | source-->| shared | private |
- * | dest | | |
- * | | | | |
- * | v | | |
- * |********************************************
- * | shared | shared (+) | shared (+) |
- * | | | |
- * |non-shared| shared (+*) | private |
- * *********************************************
- * (+) the mount is moved to the destination. And is then propagated to all
- * the mounts in the propagation tree of the destination mount.
+ * (+++) the mount is propagated to all the mounts in the propagation tree
+ * of the destination mount and the cloned mount is made slave
+ * of the same master as that of the source mount. The cloned mount
+ * is marked as 'shared and slave'.
+ * (*) the cloned mount is made a slave of the same master as that of the
+ * source mount.
+ *
+ * --------------------------------------------------------------
+ * | MOVE MOUNT OPERATION |
+ * |*************************************************************
+ * | source-->| shared | private | slave |
+ * | dest | | | |
+ * | | | | | |
+ * | v | | | |
+ * |*************************************************************
+ * | shared | shared (+) | shared (+) | shared(+++) |
+ * | | | | |
+ * |non-shared| shared (+*) | private | slave (*) |
+ * **************************************************************
+ *
+ * (+) the mount is moved to the destination. And is then propagated to
+ * all the mounts in the propagation tree of the destination mount.
* (+*) the mount is moved to the destination.
+ * (+++) the mount is moved to the destination and is then propagated to
+ * all the mounts belonging to the destination mount's propagation tree.
+ * the mount is marked as 'shared and slave'.
+ * (*) the mount continues to be a slave at the new location.
*
* if the source mount is a tree, the operations explained above is
* applied to each mount in the tree.