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VFS: Make clone_mnt()/copy_tree()/collect_mounts() return errors
copy_tree() can theoretically fail in a case other than ENOMEM, but always returns NULL which is interpreted by callers as -ENOMEM. Change it to return an explicit error. Also change clone_mnt() for consistency and because union mounts will add new error cases. Thanks to Andreas Gruenbacher <agruen@suse.de> for a bug fix. [AV: folded braino fix by Dan Carpenter] Original-author: Valerie Aurora <vaurora@redhat.com> Signed-off-by: David Howells <dhowells@redhat.com> Cc: Valerie Aurora <valerie.aurora@gmail.com> Cc: Andreas Gruenbacher <agruen@suse.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
parent
55e4def0a6
commit
be34d1a3bc
120
fs/namespace.c
120
fs/namespace.c
@ -708,56 +708,60 @@ static struct mount *clone_mnt(struct mount *old, struct dentry *root,
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int flag)
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int flag)
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{
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{
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struct super_block *sb = old->mnt.mnt_sb;
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struct super_block *sb = old->mnt.mnt_sb;
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struct mount *mnt = alloc_vfsmnt(old->mnt_devname);
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struct mount *mnt;
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int err;
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if (mnt) {
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mnt = alloc_vfsmnt(old->mnt_devname);
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if (flag & (CL_SLAVE | CL_PRIVATE))
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if (!mnt)
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mnt->mnt_group_id = 0; /* not a peer of original */
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return ERR_PTR(-ENOMEM);
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else
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mnt->mnt_group_id = old->mnt_group_id;
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if ((flag & CL_MAKE_SHARED) && !mnt->mnt_group_id) {
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if (flag & (CL_SLAVE | CL_PRIVATE))
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int err = mnt_alloc_group_id(mnt);
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mnt->mnt_group_id = 0; /* not a peer of original */
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if (err)
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else
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goto out_free;
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mnt->mnt_group_id = old->mnt_group_id;
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}
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mnt->mnt.mnt_flags = old->mnt.mnt_flags & ~MNT_WRITE_HOLD;
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if ((flag & CL_MAKE_SHARED) && !mnt->mnt_group_id) {
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atomic_inc(&sb->s_active);
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err = mnt_alloc_group_id(mnt);
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mnt->mnt.mnt_sb = sb;
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if (err)
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mnt->mnt.mnt_root = dget(root);
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goto out_free;
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mnt->mnt_mountpoint = mnt->mnt.mnt_root;
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mnt->mnt_parent = mnt;
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br_write_lock(&vfsmount_lock);
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list_add_tail(&mnt->mnt_instance, &sb->s_mounts);
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br_write_unlock(&vfsmount_lock);
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if (flag & CL_SLAVE) {
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list_add(&mnt->mnt_slave, &old->mnt_slave_list);
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mnt->mnt_master = old;
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CLEAR_MNT_SHARED(mnt);
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} else if (!(flag & CL_PRIVATE)) {
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if ((flag & CL_MAKE_SHARED) || IS_MNT_SHARED(old))
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list_add(&mnt->mnt_share, &old->mnt_share);
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if (IS_MNT_SLAVE(old))
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list_add(&mnt->mnt_slave, &old->mnt_slave);
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mnt->mnt_master = old->mnt_master;
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}
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if (flag & CL_MAKE_SHARED)
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set_mnt_shared(mnt);
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/* stick the duplicate mount on the same expiry list
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* as the original if that was on one */
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if (flag & CL_EXPIRE) {
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if (!list_empty(&old->mnt_expire))
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list_add(&mnt->mnt_expire, &old->mnt_expire);
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}
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}
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}
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mnt->mnt.mnt_flags = old->mnt.mnt_flags & ~MNT_WRITE_HOLD;
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atomic_inc(&sb->s_active);
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mnt->mnt.mnt_sb = sb;
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mnt->mnt.mnt_root = dget(root);
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mnt->mnt_mountpoint = mnt->mnt.mnt_root;
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mnt->mnt_parent = mnt;
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br_write_lock(&vfsmount_lock);
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list_add_tail(&mnt->mnt_instance, &sb->s_mounts);
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br_write_unlock(&vfsmount_lock);
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if (flag & CL_SLAVE) {
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list_add(&mnt->mnt_slave, &old->mnt_slave_list);
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mnt->mnt_master = old;
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CLEAR_MNT_SHARED(mnt);
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} else if (!(flag & CL_PRIVATE)) {
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if ((flag & CL_MAKE_SHARED) || IS_MNT_SHARED(old))
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list_add(&mnt->mnt_share, &old->mnt_share);
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if (IS_MNT_SLAVE(old))
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list_add(&mnt->mnt_slave, &old->mnt_slave);
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mnt->mnt_master = old->mnt_master;
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}
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if (flag & CL_MAKE_SHARED)
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set_mnt_shared(mnt);
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/* stick the duplicate mount on the same expiry list
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* as the original if that was on one */
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if (flag & CL_EXPIRE) {
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if (!list_empty(&old->mnt_expire))
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list_add(&mnt->mnt_expire, &old->mnt_expire);
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}
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return mnt;
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return mnt;
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out_free:
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out_free:
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free_vfsmnt(mnt);
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free_vfsmnt(mnt);
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return NULL;
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return ERR_PTR(err);
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}
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}
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static inline void mntfree(struct mount *mnt)
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static inline void mntfree(struct mount *mnt)
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@ -1242,11 +1246,12 @@ struct mount *copy_tree(struct mount *mnt, struct dentry *dentry,
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struct path path;
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struct path path;
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if (!(flag & CL_COPY_ALL) && IS_MNT_UNBINDABLE(mnt))
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if (!(flag & CL_COPY_ALL) && IS_MNT_UNBINDABLE(mnt))
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return NULL;
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return ERR_PTR(-EINVAL);
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res = q = clone_mnt(mnt, dentry, flag);
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res = q = clone_mnt(mnt, dentry, flag);
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if (!q)
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if (IS_ERR(q))
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goto Enomem;
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return q;
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q->mnt_mountpoint = mnt->mnt_mountpoint;
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q->mnt_mountpoint = mnt->mnt_mountpoint;
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p = mnt;
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p = mnt;
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@ -1268,8 +1273,8 @@ struct mount *copy_tree(struct mount *mnt, struct dentry *dentry,
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path.mnt = &q->mnt;
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path.mnt = &q->mnt;
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path.dentry = p->mnt_mountpoint;
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path.dentry = p->mnt_mountpoint;
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q = clone_mnt(p, p->mnt.mnt_root, flag);
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q = clone_mnt(p, p->mnt.mnt_root, flag);
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if (!q)
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if (IS_ERR(q))
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goto Enomem;
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goto out;
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br_write_lock(&vfsmount_lock);
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br_write_lock(&vfsmount_lock);
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list_add_tail(&q->mnt_list, &res->mnt_list);
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list_add_tail(&q->mnt_list, &res->mnt_list);
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attach_mnt(q, &path);
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attach_mnt(q, &path);
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@ -1277,7 +1282,7 @@ struct mount *copy_tree(struct mount *mnt, struct dentry *dentry,
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}
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}
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}
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}
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return res;
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return res;
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Enomem:
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out:
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if (res) {
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if (res) {
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LIST_HEAD(umount_list);
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LIST_HEAD(umount_list);
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br_write_lock(&vfsmount_lock);
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br_write_lock(&vfsmount_lock);
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@ -1285,9 +1290,11 @@ Enomem:
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br_write_unlock(&vfsmount_lock);
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br_write_unlock(&vfsmount_lock);
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release_mounts(&umount_list);
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release_mounts(&umount_list);
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}
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}
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return NULL;
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return q;
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}
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}
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/* Caller should check returned pointer for errors */
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struct vfsmount *collect_mounts(struct path *path)
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struct vfsmount *collect_mounts(struct path *path)
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{
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{
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struct mount *tree;
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struct mount *tree;
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@ -1295,7 +1302,9 @@ struct vfsmount *collect_mounts(struct path *path)
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tree = copy_tree(real_mount(path->mnt), path->dentry,
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tree = copy_tree(real_mount(path->mnt), path->dentry,
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CL_COPY_ALL | CL_PRIVATE);
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CL_COPY_ALL | CL_PRIVATE);
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up_write(&namespace_sem);
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up_write(&namespace_sem);
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return tree ? &tree->mnt : NULL;
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if (IS_ERR(tree))
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return NULL;
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return &tree->mnt;
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}
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}
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void drop_collected_mounts(struct vfsmount *mnt)
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void drop_collected_mounts(struct vfsmount *mnt)
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@ -1590,14 +1599,15 @@ static int do_loopback(struct path *path, char *old_name,
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if (!check_mnt(real_mount(path->mnt)) || !check_mnt(old))
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if (!check_mnt(real_mount(path->mnt)) || !check_mnt(old))
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goto out2;
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goto out2;
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err = -ENOMEM;
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if (recurse)
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if (recurse)
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mnt = copy_tree(old, old_path.dentry, 0);
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mnt = copy_tree(old, old_path.dentry, 0);
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else
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else
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mnt = clone_mnt(old, old_path.dentry, 0);
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mnt = clone_mnt(old, old_path.dentry, 0);
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if (!mnt)
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if (IS_ERR(mnt)) {
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goto out2;
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err = PTR_ERR(mnt);
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goto out;
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}
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err = graft_tree(mnt, path);
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err = graft_tree(mnt, path);
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if (err) {
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if (err) {
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@ -2211,10 +2221,10 @@ static struct mnt_namespace *dup_mnt_ns(struct mnt_namespace *mnt_ns,
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down_write(&namespace_sem);
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down_write(&namespace_sem);
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/* First pass: copy the tree topology */
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/* First pass: copy the tree topology */
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new = copy_tree(old, old->mnt.mnt_root, CL_COPY_ALL | CL_EXPIRE);
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new = copy_tree(old, old->mnt.mnt_root, CL_COPY_ALL | CL_EXPIRE);
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if (!new) {
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if (IS_ERR(new)) {
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up_write(&namespace_sem);
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up_write(&namespace_sem);
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kfree(new_ns);
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kfree(new_ns);
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return ERR_PTR(-ENOMEM);
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return ERR_CAST(new);
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}
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}
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new_ns->root = new;
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new_ns->root = new;
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br_write_lock(&vfsmount_lock);
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br_write_lock(&vfsmount_lock);
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@ -237,8 +237,9 @@ int propagate_mnt(struct mount *dest_mnt, struct dentry *dest_dentry,
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source = get_source(m, prev_dest_mnt, prev_src_mnt, &type);
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source = get_source(m, prev_dest_mnt, prev_src_mnt, &type);
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if (!(child = copy_tree(source, source->mnt.mnt_root, type))) {
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child = copy_tree(source, source->mnt.mnt_root, type);
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ret = -ENOMEM;
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if (IS_ERR(child)) {
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ret = PTR_ERR(child);
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list_splice(tree_list, tmp_list.prev);
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list_splice(tree_list, tmp_list.prev);
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goto out;
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goto out;
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}
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}
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@ -595,7 +595,7 @@ void audit_trim_trees(void)
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root_mnt = collect_mounts(&path);
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root_mnt = collect_mounts(&path);
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path_put(&path);
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path_put(&path);
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if (!root_mnt)
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if (IS_ERR(root_mnt))
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goto skip_it;
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goto skip_it;
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spin_lock(&hash_lock);
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spin_lock(&hash_lock);
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@ -669,8 +669,8 @@ int audit_add_tree_rule(struct audit_krule *rule)
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goto Err;
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goto Err;
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mnt = collect_mounts(&path);
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mnt = collect_mounts(&path);
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path_put(&path);
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path_put(&path);
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if (!mnt) {
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if (IS_ERR(mnt)) {
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err = -ENOMEM;
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err = PTR_ERR(mnt);
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goto Err;
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goto Err;
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}
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}
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@ -719,8 +719,8 @@ int audit_tag_tree(char *old, char *new)
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return err;
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return err;
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tagged = collect_mounts(&path2);
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tagged = collect_mounts(&path2);
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path_put(&path2);
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path_put(&path2);
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if (!tagged)
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if (IS_ERR(tagged))
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return -ENOMEM;
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return PTR_ERR(tagged);
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err = kern_path(old, 0, &path1);
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err = kern_path(old, 0, &path1);
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if (err) {
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if (err) {
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