CIFS: Use d_automount() rather than abusing follow_link()
Make CIFS use the new d_automount() dentry operation rather than abusing
follow_link() on directories.
[NOTE: THIS IS UNTESTED!]
Signed-off-by: David Howells <dhowells@redhat.com>
Cc: Steve French <sfrench@samba.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/cifs/cifs_dfs_ref.c b/fs/cifs/cifs_dfs_ref.c
index 83479cf..0fc1638 100644
--- a/fs/cifs/cifs_dfs_ref.c
+++ b/fs/cifs/cifs_dfs_ref.c
@@ -255,32 +255,6 @@
}
-static int add_mount_helper(struct vfsmount *newmnt, struct nameidata *nd,
- struct list_head *mntlist)
-{
- /* stolen from afs code */
- int err;
-
- mntget(newmnt);
- err = do_add_mount(newmnt, &nd->path, nd->path.mnt->mnt_flags | MNT_SHRINKABLE, mntlist);
- switch (err) {
- case 0:
- path_put(&nd->path);
- nd->path.mnt = newmnt;
- nd->path.dentry = dget(newmnt->mnt_root);
- schedule_delayed_work(&cifs_dfs_automount_task,
- cifs_dfs_mountpoint_expiry_timeout);
- break;
- case -EBUSY:
- /* someone else made a mount here whilst we were busy */
- err = follow_down(&nd->path, false);
- default:
- mntput(newmnt);
- break;
- }
- return err;
-}
-
static void dump_referral(const struct dfs_info3_param *ref)
{
cFYI(1, "DFS: ref path: %s", ref->path_name);
@@ -290,45 +264,43 @@
ref->path_consumed);
}
-
-static void*
-cifs_dfs_follow_mountpoint(struct dentry *dentry, struct nameidata *nd)
+/*
+ * Create a vfsmount that we can automount
+ */
+static struct vfsmount *cifs_dfs_do_automount(struct dentry *mntpt)
{
struct dfs_info3_param *referrals = NULL;
unsigned int num_referrals = 0;
struct cifs_sb_info *cifs_sb;
struct cifsSesInfo *ses;
- char *full_path = NULL;
+ char *full_path;
int xid, i;
- int rc = 0;
- struct vfsmount *mnt = ERR_PTR(-ENOENT);
+ int rc;
+ struct vfsmount *mnt;
struct tcon_link *tlink;
cFYI(1, "in %s", __func__);
- BUG_ON(IS_ROOT(dentry));
+ BUG_ON(IS_ROOT(mntpt));
xid = GetXid();
- dput(nd->path.dentry);
- nd->path.dentry = dget(dentry);
-
/*
* The MSDFS spec states that paths in DFS referral requests and
* responses must be prefixed by a single '\' character instead of
* the double backslashes usually used in the UNC. This function
* gives us the latter, so we must adjust the result.
*/
- full_path = build_path_from_dentry(dentry);
- if (full_path == NULL) {
- rc = -ENOMEM;
- goto out_err;
- }
+ mnt = ERR_PTR(-ENOMEM);
+ full_path = build_path_from_dentry(mntpt);
+ if (full_path == NULL)
+ goto free_xid;
- cifs_sb = CIFS_SB(dentry->d_inode->i_sb);
+ cifs_sb = CIFS_SB(mntpt->d_inode->i_sb);
tlink = cifs_sb_tlink(cifs_sb);
+ mnt = ERR_PTR(-EINVAL);
if (IS_ERR(tlink)) {
- rc = PTR_ERR(tlink);
- goto out_err;
+ mnt = ERR_CAST(tlink);
+ goto free_full_path;
}
ses = tlink_tcon(tlink)->ses;
@@ -338,46 +310,77 @@
cifs_put_tlink(tlink);
+ mnt = ERR_PTR(-ENOENT);
for (i = 0; i < num_referrals; i++) {
int len;
- dump_referral(referrals+i);
+ dump_referral(referrals + i);
/* connect to a node */
len = strlen(referrals[i].node_name);
if (len < 2) {
cERROR(1, "%s: Net Address path too short: %s",
__func__, referrals[i].node_name);
- rc = -EINVAL;
- goto out_err;
+ mnt = ERR_PTR(-EINVAL);
+ break;
}
mnt = cifs_dfs_do_refmount(cifs_sb,
full_path, referrals + i);
cFYI(1, "%s: cifs_dfs_do_refmount:%s , mnt:%p", __func__,
referrals[i].node_name, mnt);
-
- /* complete mount procedure if we accured submount */
if (!IS_ERR(mnt))
- break;
+ goto success;
}
- /* we need it cause for() above could exit without valid submount */
- rc = PTR_ERR(mnt);
- if (IS_ERR(mnt))
- goto out_err;
+ /* no valid submounts were found; return error from get_dfs_path() by
+ * preference */
+ if (rc != 0)
+ mnt = ERR_PTR(rc);
- rc = add_mount_helper(mnt, nd, &cifs_dfs_automount_list);
-
-out:
- FreeXid(xid);
+success:
free_dfs_info_array(referrals, num_referrals);
+free_full_path:
kfree(full_path);
+free_xid:
+ FreeXid(xid);
cFYI(1, "leaving %s" , __func__);
- return ERR_PTR(rc);
-out_err:
- path_put(&nd->path);
- goto out;
+ return mnt;
+}
+
+/*
+ * Attempt to automount the referral
+ */
+struct vfsmount *cifs_dfs_d_automount(struct path *path)
+{
+ struct vfsmount *newmnt;
+ int err;
+
+ cFYI(1, "in %s", __func__);
+
+ newmnt = cifs_dfs_do_automount(path->dentry);
+ if (IS_ERR(newmnt)) {
+ cFYI(1, "leaving %s [automount failed]" , __func__);
+ return newmnt;
+ }
+
+ mntget(newmnt);
+ err = do_add_mount(newmnt, path, path->mnt->mnt_flags | MNT_SHRINKABLE,
+ &cifs_dfs_automount_list);
+ switch (err) {
+ case 0:
+ schedule_delayed_work(&cifs_dfs_automount_task,
+ cifs_dfs_mountpoint_expiry_timeout);
+ cFYI(1, "leaving %s [ok]" , __func__);
+ return newmnt;
+ case -EBUSY:
+ /* someone else made a mount here whilst we were busy */
+ mntput(newmnt);
+ cFYI(1, "leaving %s [EBUSY]" , __func__);
+ return NULL;
+ default:
+ mntput(newmnt);
+ cFYI(1, "leaving %s [error %d]" , __func__, err);
+ return ERR_PTR(err);
+ }
}
const struct inode_operations cifs_dfs_referral_inode_operations = {
- .follow_link = cifs_dfs_follow_mountpoint,
};
-