From: Ram <linuxram@us.ibm.com>
To: linux-kernel@vger.kernel.org
Cc: linux-fsdevel@vger.kernel.org,
viro@parcelfarce.linux.theplanet.co.uk,
Andrew Morton <akpm@osdl.org>,
mike@waychison.com, bfields@fieldses.org,
Miklos Szeredi <miklos@szeredi.hu>
Subject: [RFC PATCH 4/8] move a shared/private/slave/unclone tree
Date: Fri, 08 Jul 2005 03:25:51 -0700 [thread overview]
Message-ID: <1120817640.30164.49.camel@localhost> (raw)
In-Reply-To: <1120816521.30164.22.camel@localhost>
[-- Attachment #1: Type: text/plain, Size: 164 bytes --]
Adds ability to move a shared/private/slave/unclone tree to any other
shared/private/slave/unclone tree. Also incorporates the same behavior
for pivot_root()
RP
[-- Attachment #2: move.patch --]
[-- Type: text/x-patch, Size: 8297 bytes --]
Adds ability to move a shared/private/slave/unclone tree to any other
shared/private/slave/unclone tree. Also incorporates the same behavior
for pivot_root()
RP
Signed by Ram Pai (linuxram@us.ibm.com)
namespace.c | 106 +++++++++++++++++++++++++++++++++++++++++++++++++++++-------
1 files changed, 94 insertions(+), 12 deletions(-)
Index: 2.6.12/fs/namespace.c
===================================================================
--- 2.6.12.orig/fs/namespace.c
+++ 2.6.12/fs/namespace.c
@@ -656,9 +656,12 @@ static struct vfsmount *copy_tree(struct
return NULL;
}
+
/*
* @source_mnt : mount tree to be attached
* @nd : place the mount tree @source_mnt is attached
+ * @move : use the move semantics if set, else use normal attach semantics
+ * as explained below
*
* NOTE: in the table below explains the semantics when a source vfsmount
* of a given type is attached to a destination vfsmount of a give type.
@@ -691,6 +694,34 @@ static struct vfsmount *copy_tree(struct
* (+) the mount will be propogated to the destination vfsmount
* and the new mount will be added to the source vfsmount's pnode.
*
+ * -----------------------------------------------------------------------------
+ * | MOVE MOUNT SEMANTICS |
+ * |***************************************************************************|
+ * | dest --> | shared | private | slave |unclonable |
+ * | source | | | | |
+ * | | | | | | |
+ * | v | | | | |
+ * |***************************************************************************|
+ * | | | | | |
+ * | shared | shared (++) | shared (+) | shared (+) | shared (+)|
+ * | | | | | |
+ * | | | | | |
+ * | private | shared (+) | private | private | private |
+ * | | | | | |
+ * | | | | | |
+ * | slave | shared (+++) | slave | slave | slave |
+ * | | | | | |
+ * | | | | | |
+ * | unclonable| unclonable | unclonable | unclonable | unclonable|
+ * | | | | | |
+ * | | | | | |
+ * |***************************************************************************|
+ *
+ * (+++) the mount will be propogated to all the vfsmounts in the pnode tree
+ * of the destination vfsmount, and all the new mounts will be
+ * added to a new pnode , which will be a slave pnode of the
+ * source vfsmount's pnode.
+ *
* if the source mount is a tree, the operations explained above is applied to each
* vfsmount in the tree.
*
@@ -699,7 +730,7 @@ static struct vfsmount *copy_tree(struct
*
*/
static void
-attach_recursive_mnt(struct vfsmount *source_mnt, struct nameidata *nd)
+attach_recursive_mnt(struct vfsmount *source_mnt, struct nameidata *nd, int move)
{
struct vfsmount *mntpt_mnt, *m, *p;
struct vfspnode *src_pnode, *t_p, *dest_pnode, *tmp_pnode;
@@ -729,6 +760,7 @@ attach_recursive_mnt(struct vfsmount *so
p = NULL;
for (m = source_mnt; m; m = next_mnt(m, source_mnt)) {
int unclone = IS_MNT_UNCLONABLE(m);
+ int slave = IS_MNT_SLAVE(m);
list_del_init(&m->mnt_list);
@@ -747,7 +779,7 @@ attach_recursive_mnt(struct vfsmount *so
p=m;
dest_pnode = IS_MNT_SHARED(mntpt_mnt) ?
mntpt_mnt->mnt_pnode : NULL;
- src_pnode = (IS_MNT_SHARED(m))?
+ src_pnode = (IS_MNT_SHARED(m) || (move && dest_pnode && slave))?
m->mnt_pnode : NULL;
m->mnt_pnode = NULL;
@@ -766,14 +798,20 @@ attach_recursive_mnt(struct vfsmount *so
if (m == m->mnt_parent)
do_attach_prepare_mnt(mntpt_mnt,
mntpt_dentry, m, 0);
- pnode_add_member_mnt(tmp_pnode, m);
- if (unclone)
- SET_MNT_UNCLONABLE(m);
+ if (move && slave)
+ pnode_add_slave_mnt(tmp_pnode, m);
+ else {
+ pnode_add_member_mnt(tmp_pnode, m);
+ if (unclone)
+ SET_MNT_UNCLONABLE(m);
+ }
}
if ((!src_pnode && !dest_pnode) || unclone)
SET_PNODE_DELETE(tmp_pnode);
tmp_pnode->pnode_master = src_pnode;
+ if (move && dest_pnode && slave)
+ SET_PNODE_SLAVE(tmp_pnode);
/*
* temporarily track the pnode with which the tmp_pnode
* has to merge with; in the pnode_master field.
@@ -787,12 +825,16 @@ attach_recursive_mnt(struct vfsmount *so
spin_lock(&vfsmount_lock);
list_for_each_entry_safe(tmp_pnode, t_p, &pnodehead, pnode_peer_slave) {
int del_flag = IS_PNODE_DELETE(tmp_pnode);
+ int slave_flag = IS_PNODE_SLAVE(tmp_pnode);
struct vfspnode *master_pnode = tmp_pnode->pnode_master;
list_del_init(&tmp_pnode->pnode_peer_slave);
pnode_real_mount(tmp_pnode, del_flag);
if (!del_flag && master_pnode) {
tmp_pnode->pnode_master = NULL;
- pnode_merge_pnode(tmp_pnode, master_pnode);
+ if (slave_flag)
+ pnode_add_slave_pnode(master_pnode, tmp_pnode);
+ else
+ pnode_merge_pnode(tmp_pnode, master_pnode);
/*
* we don't need the extra reference to
* the master_pnode, that was created either
@@ -809,6 +851,18 @@ out:
return;
}
+static void
+detach_recursive_mnt(struct vfsmount *source_mnt, struct nameidata *nd)
+{
+ struct vfsmount *m;
+
+ detach_mnt(source_mnt, nd);
+ for (m = source_mnt; m; m = next_mnt(m, source_mnt)) {
+ list_del_init(&m->mnt_pnode_mntlist);
+ }
+ return;
+}
+
static int graft_tree(struct vfsmount *mnt, struct nameidata *nd)
{
int err, ret;
@@ -835,7 +889,7 @@ static int graft_tree(struct vfsmount *m
ret = (IS_ROOT(nd->dentry) || !d_unhashed(nd->dentry));
spin_unlock(&vfsmount_lock);
if (ret) {
- attach_recursive_mnt(mnt, nd);
+ attach_recursive_mnt(mnt, nd, 0);
err = 0;
}
out_unlock:
@@ -1195,6 +1249,12 @@ static int do_move_mount(struct nameidat
if (S_ISDIR(nd->dentry->d_inode->i_mode) !=
S_ISDIR(old_nd.dentry->d_inode->i_mode))
goto out2;
+ /*
+ * Don't move a mount in a shared parent.
+ */
+ if(old_nd.mnt->mnt_parent &&
+ IS_MNT_SHARED(old_nd.mnt->mnt_parent))
+ goto out2;
err = -ELOOP;
for (p = nd->mnt; p->mnt_parent!=p; p = p->mnt_parent)
@@ -1202,8 +1262,14 @@ static int do_move_mount(struct nameidat
goto out2;
err = 0;
- detach_mnt(old_nd.mnt, &parent_nd);
- attach_mnt(old_nd.mnt, nd);
+ detach_recursive_mnt(old_nd.mnt, &parent_nd);
+ if(IS_MNT_SHARED(nd->mnt)) {
+ spin_unlock(&vfsmount_lock);
+ attach_recursive_mnt(old_nd.mnt, nd, 1);
+ spin_lock(&vfsmount_lock);
+ mntput(old_nd.mnt);
+ } else
+ attach_mnt(old_nd.mnt, nd);
/* if the mount is moved, it should no longer be expire
* automatically */
@@ -1794,6 +1860,16 @@ asmlinkage long sys_pivot_root(const cha
goto out2; /* not a mountpoint */
if (new_nd.mnt->mnt_root != new_nd.dentry)
goto out2; /* not a mountpoint */
+ /*
+ * Don't move a mount in a shared parent.
+ */
+ if(user_nd.mnt->mnt_parent &&
+ IS_MNT_SHARED(user_nd.mnt->mnt_parent))
+ goto out2;
+ if(new_nd.mnt->mnt_parent &&
+ IS_MNT_SHARED(new_nd.mnt->mnt_parent))
+ goto out2;
+
tmp = old_nd.mnt; /* make sure we can reach put_old from new_root */
spin_lock(&vfsmount_lock);
if (tmp != new_nd.mnt) {
@@ -1808,10 +1884,22 @@ asmlinkage long sys_pivot_root(const cha
goto out3;
} else if (!is_subdir(old_nd.dentry, new_nd.dentry))
goto out3;
- detach_mnt(new_nd.mnt, &parent_nd);
- detach_mnt(user_nd.mnt, &root_parent);
- attach_mnt(user_nd.mnt, &old_nd); /* mount old root on put_old */
- attach_mnt(new_nd.mnt, &root_parent); /* mount new_root on / */
+ detach_recursive_mnt(new_nd.mnt, &parent_nd);
+ detach_recursive_mnt(user_nd.mnt, &root_parent);
+ if(IS_MNT_SHARED(old_nd.mnt)) {
+ spin_unlock(&vfsmount_lock);
+ attach_recursive_mnt(user_nd.mnt, &old_nd, 1);
+ spin_lock(&vfsmount_lock);
+ mntput(user_nd.mnt);
+ } else
+ attach_mnt(user_nd.mnt, &old_nd);
+ if(IS_MNT_SHARED(root_parent.mnt)) {
+ spin_unlock(&vfsmount_lock);
+ attach_recursive_mnt(new_nd.mnt, &root_parent, 1);
+ spin_lock(&vfsmount_lock);
+ mntput(new_nd.mnt);
+ } else
+ attach_mnt(new_nd.mnt, &root_parent);
spin_unlock(&vfsmount_lock);
chroot_fs_refs(&user_nd, &new_nd);
security_sb_post_pivotroot(&user_nd, &new_nd);
next prev parent reply other threads:[~2005-07-08 10:50 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1120816072.30164.10.camel@localhost>
2005-07-08 10:25 ` [RFC PATCH 0/8] shared subtree Ram
[not found] ` <1120816229.30164.13.camel@localhost>
2005-07-08 10:25 ` [RFC PATCH 1/8] share/private/slave a subtree Ram
2005-07-08 11:17 ` Pekka Enberg
2005-07-08 12:19 ` Roman Zippel
2005-07-08 12:26 ` Pekka J Enberg
2005-07-08 12:46 ` Roman Zippel
2005-07-08 12:58 ` Pekka J Enberg
2005-07-08 13:34 ` Roman Zippel
2005-07-08 16:17 ` Pekka Enberg
2005-07-08 16:33 ` share/private/slave a subtree - define vs enum Bryan Henderson
2005-07-08 16:57 ` Roman Zippel
2005-07-08 17:16 ` Bryan Henderson
2005-07-08 18:21 ` Pekka J Enberg
2005-07-08 19:11 ` Roman Zippel
2005-07-08 19:33 ` Pekka Enberg
2005-07-08 19:59 ` Roman Zippel
2005-07-10 18:21 ` Pekka Enberg
2005-07-10 18:40 ` randy_dunlap
2005-07-10 19:14 ` Roman Zippel
2005-07-11 6:37 ` Pekka J Enberg
2005-07-11 17:13 ` Horst von Brand
2005-07-11 17:57 ` Roman Zippel
2005-07-10 19:16 ` Vojtech Pavlik
2005-07-11 17:18 ` Horst von Brand
2005-07-08 19:38 ` Ram
2005-07-08 22:12 ` Bryan Henderson
2005-07-10 10:55 ` Denis Vlasenko
2005-07-08 18:03 ` Wichert Akkerman
2005-07-08 18:10 ` Mike Waychison
2005-07-08 18:15 ` Wichert Akkerman
2005-07-08 20:23 ` Mike Waychison
2005-07-10 21:57 ` Pavel Machek
2005-07-08 16:29 ` [RFC PATCH 1/8] share/private/slave a subtree Ram
2005-07-08 14:32 ` Miklos Szeredi
2005-07-08 16:19 ` Ram
2005-07-08 16:51 ` Miklos Szeredi
2005-07-08 17:52 ` Ram
2005-07-08 19:49 ` Miklos Szeredi
2005-07-14 1:27 ` Ram
2005-07-18 11:06 ` shared subtrees implementation writeup Miklos Szeredi
2005-07-18 17:18 ` Ram Pai
[not found] ` <1120816355.30164.16.camel@localhost>
2005-07-08 10:25 ` [RFC PATCH 2/8] unclone a subtree Ram
[not found] ` <1120816436.30164.19.camel@localhost>
2005-07-08 10:25 ` [RFC PATCH 3/8] bind/rbind a shared/private/slave/unclone tree Ram
[not found] ` <1120816521.30164.22.camel@localhost>
2005-07-08 10:25 ` Ram [this message]
[not found] ` <1120816600.30164.25.camel@localhost>
2005-07-08 10:25 ` [RFC PATCH 5/8] umount " Ram
[not found] ` <1120816720.30164.28.camel@localhost>
2005-07-08 10:26 ` [RFC PATCH 6/8] clone a namespace containing " Ram
[not found] ` <1120816835.30164.31.camel@localhost>
2005-07-08 10:26 ` [RFC PATCH 7/8] automounter support for shared/slave/private/unclone Ram
2005-07-08 10:26 ` [RFC PATCH 8/8] pnode.c optimization Ram
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