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Subject[PATCH -mm 5/8] user ns: prepare copy_tree, copy_mnt, and their callers to handle errs
From: Serge E. Hallyn <serue@us.ibm.com>
Subject: [PATCH -mm 5/8] user ns: prepare copy_tree, copy_mnt, and their callers to handle errs

With shareduserns and non-shareduserns mounts, it will be possible
for clone_mnt to return -EPERM if a namespace tries to bind
mount a non-shareduserns vfsmnt from another user namespace.
But currently they only return NULL, which is interpreted as
-ENOMEM. Update the callers to handle other errors.

Signed-off-by: Serge E. Hallyn <serue@us.ibm.com>
---
fs/namespace.c | 20 ++++++++++++--------
fs/pnode.c | 5 +++--
2 files changed, 15 insertions(+), 10 deletions(-)

diff --git a/fs/namespace.c b/fs/namespace.c
index 5da87e2..a4039a3 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -708,8 +708,9 @@ struct vfsmount *copy_tree(struct vfsmou
return NULL;

res = q = clone_mnt(mnt, dentry, flag);
- if (!q)
- goto Enomem;
+ if (!q || IS_ERR(q)) {
+ return q;
+ }
q->mnt_mountpoint = mnt->mnt_mountpoint;

p = mnt;
@@ -730,8 +731,9 @@ struct vfsmount *copy_tree(struct vfsmou
nd.mnt = q;
nd.dentry = p->mnt_mountpoint;
q = clone_mnt(p, p->mnt_root, flag);
- if (!q)
- goto Enomem;
+ if (!q || IS_ERR(q)) {
+ goto Error;
+ }
spin_lock(&vfsmount_lock);
list_add_tail(&q->mnt_list, &res->mnt_list);
attach_mnt(q, &nd);
@@ -739,7 +741,7 @@ struct vfsmount *copy_tree(struct vfsmou
}
}
return res;
-Enomem:
+Error:
if (res) {
LIST_HEAD(umount_list);
spin_lock(&vfsmount_lock);
@@ -747,7 +749,7 @@ Enomem:
spin_unlock(&vfsmount_lock);
release_mounts(&umount_list);
}
- return NULL;
+ return q;
}

/*
@@ -927,8 +929,10 @@ static int do_loopback(struct nameidata
else
mnt = clone_mnt(old_nd.mnt, old_nd.dentry, 0);

- if (!mnt)
+ if (!mnt || IS_ERR(mnt)) {
+ err = mnt ? PTR_ERR(mnt) : -ENOMEM;
goto out;
+ }

err = graft_tree(mnt, nd);
if (err) {
@@ -1465,7 +1469,7 @@ struct mnt_namespace *dup_mnt_ns(struct
/* First pass: copy the tree topology */
new_ns->root = copy_tree(mnt_ns->root, mnt_ns->root->mnt_root,
CL_COPY_ALL | CL_EXPIRE);
- if (!new_ns->root) {
+ if (!new_ns->root || IS_ERR(new_ns->root)) {
up_write(&namespace_sem);
kfree(new_ns);
return NULL;
diff --git a/fs/pnode.c b/fs/pnode.c
index 56aacea..1821c95 100644
--- a/fs/pnode.c
+++ b/fs/pnode.c
@@ -187,8 +187,9 @@ int propagate_mnt(struct vfsmount *dest_

source = get_source(m, prev_dest_mnt, prev_src_mnt, &type);

- if (!(child = copy_tree(source, source->mnt_root, type))) {
- ret = -ENOMEM;
+ child = copy_tree(source, source->mnt_root, type);
+ if (!child || IS_ERR(child)) {
+ ret = child ? PTR_ERR(child) : -ENOMEM;
list_splice(tree_list, tmp_list.prev);
goto out;
}
--
1.4.1
-
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