do_add_mount(): lift lock_mount/unlock_mount into callers

preparation to finish_automount() fix (next commit)

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

diff --git a/fs/namespace.c b/fs/namespace.c
index 85b5f7b..dcd015f 100644 (file)
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -2697,45 +2697,32 @@ static int do_move_mount_old(struct path *path, const char *old_name)
 /*
  * add a mount into a namespace's mount tree
  */
-static int do_add_mount(struct mount *newmnt, struct path *path, int mnt_flags)
+static int do_add_mount(struct mount *newmnt, struct mountpoint *mp,
+                       struct path *path, int mnt_flags)
 {
-       struct mountpoint *mp;
-       struct mount *parent;
-       int err;
+       struct mount *parent = real_mount(path->mnt);
 
        mnt_flags &= ~MNT_INTERNAL_FLAGS;
 
-       mp = lock_mount(path);
-       if (IS_ERR(mp))
-               return PTR_ERR(mp);
-
-       parent = real_mount(path->mnt);
-       err = -EINVAL;
        if (unlikely(!check_mnt(parent))) {
                /* that's acceptable only for automounts done in private ns */
                if (!(mnt_flags & MNT_SHRINKABLE))
-                       goto unlock;
+                       return -EINVAL;
                /* ... and for those we'd better have mountpoint still alive */
                if (!parent->mnt_ns)
-                       goto unlock;
+                       return -EINVAL;
        }
 
        /* Refuse the same filesystem on the same mount point */
-       err = -EBUSY;
        if (path->mnt->mnt_sb == newmnt->mnt.mnt_sb &&
            path->mnt->mnt_root == path->dentry)
-               goto unlock;
+               return -EBUSY;
 
-       err = -EINVAL;
        if (d_is_symlink(newmnt->mnt.mnt_root))
-               goto unlock;
+               return -EINVAL;
 
        newmnt->mnt.mnt_flags = mnt_flags;
-       err = graft_tree(newmnt, parent, mp);
-
-unlock:
-       unlock_mount(mp);
-       return err;
+       return graft_tree(newmnt, parent, mp);
 }
 
 static bool mount_too_revealing(const struct super_block *sb, int *new_mnt_flags);
@@ -2748,6 +2735,7 @@ static int do_new_mount_fc(struct fs_context *fc, struct path *mountpoint,
                           unsigned int mnt_flags)
 {
        struct vfsmount *mnt;
+       struct mountpoint *mp;
        struct super_block *sb = fc->root->d_sb;
        int error;
 
@@ -2768,7 +2756,13 @@ static int do_new_mount_fc(struct fs_context *fc, struct path *mountpoint,
 
        mnt_warn_timestamp_expiry(mountpoint, mnt);
 
-       error = do_add_mount(real_mount(mnt), mountpoint, mnt_flags);
+       mp = lock_mount(mountpoint);
+       if (IS_ERR(mp)) {
+               mntput(mnt);
+               return PTR_ERR(mp);
+       }
+       error = do_add_mount(real_mount(mnt), mp, mountpoint, mnt_flags);
+       unlock_mount(mp);
        if (error < 0)
                mntput(mnt);
        return error;
@@ -2830,6 +2824,7 @@ static int do_new_mount(struct path *path, const char *fstype, int sb_flags,
 int finish_automount(struct vfsmount *m, struct path *path)
 {
        struct mount *mnt = real_mount(m);
+       struct mountpoint *mp;
        int err;
        /* The new mount record should have at least 2 refs to prevent it being
         * expired before we get a chance to add it
@@ -2842,7 +2837,13 @@ int finish_automount(struct vfsmount *m, struct path *path)
                goto fail;
        }
 
-       err = do_add_mount(mnt, path, path->mnt->mnt_flags | MNT_SHRINKABLE);
+       mp = lock_mount(path);
+       if (IS_ERR(mp)) {
+               err = PTR_ERR(mp);
+               goto fail;
+       }
+       err = do_add_mount(mnt, mp, path, path->mnt->mnt_flags | MNT_SHRINKABLE);
+       unlock_mount(mp);
        if (!err)
                return 0;
 fail: