ovl: split out ovl_get_lower_layers() from ovl_fill_super() (c0d91fb9) · Commits · 戴 / test

fs/overlayfs/super.c

+52 −38

Original line number	Diff line number	Diff line
		@@ -1038,6 +1038,55 @@ out_free_stack:
		goto out;
		}

		static int ovl_get_lower_layers(struct ovl_fs ufs, struct path stack,
		unsigned int numlower)
		{
		int err;
		unsigned int i;

		err = -ENOMEM;
		ufs->lower_layers = kcalloc(numlower, sizeof(struct ovl_layer),
		GFP_KERNEL);
		if (ufs->lower_layers == NULL)
		goto out;
		for (i = 0; i < numlower; i++) {
		struct vfsmount *mnt;
		dev_t dev;

		err = get_anon_bdev(&dev);
		if (err) {
		pr_err("overlayfs: failed to get anonymous bdev for lowerpath\n");
		goto out;
		}

		mnt = clone_private_mount(&stack[i]);
		err = PTR_ERR(mnt);
		if (IS_ERR(mnt)) {
		pr_err("overlayfs: failed to clone lowerpath\n");
		free_anon_bdev(dev);
		goto out;
		}
		/*
		* Make lower layers R/O. That way fchmod/fchown on lower file
		* will fail instead of modifying lower fs.
		*/
		mnt->mnt_flags \|= MNT_READONLY \| MNT_NOATIME;

		ufs->lower_layers[ufs->numlower].mnt = mnt;
		ufs->lower_layers[ufs->numlower].pseudo_dev = dev;
		ufs->numlower++;

		/* Check if all lower layers are on same sb */
		if (i == 0)
		ufs->same_sb = mnt->mnt_sb;
		else if (ufs->same_sb != mnt->mnt_sb)
		ufs->same_sb = NULL;
		}
		err = 0;
		out:
		return err;
		}

		static int ovl_fill_super(struct super_block sb, void data, int silent)
		{
		struct path upperpath = { };
		@@ -1103,44 +1152,9 @@ static int ovl_fill_super(struct super_block sb, void data, int silent)
		goto out_put_workdir;
		}

		err = -ENOMEM;
		ufs->lower_layers = kcalloc(numlower, sizeof(struct ovl_layer),
		GFP_KERNEL);
		if (ufs->lower_layers == NULL)
		goto out_put_workdir;
		for (i = 0; i < numlower; i++) {
		struct vfsmount *mnt;
		dev_t dev;

		err = get_anon_bdev(&dev);
		if (err) {
		pr_err("overlayfs: failed to get anonymous bdev for lowerpath\n");
		goto out_put_lower_layers;
		}

		mnt = clone_private_mount(&stack[i]);
		err = PTR_ERR(mnt);
		if (IS_ERR(mnt)) {
		pr_err("overlayfs: failed to clone lowerpath\n");
		free_anon_bdev(dev);
		err = ovl_get_lower_layers(ufs, stack, numlower);
		if (err)
		goto out_put_lower_layers;
		}
		/*
		* Make lower layers R/O. That way fchmod/fchown on lower file
		* will fail instead of modifying lower fs.
		*/
		mnt->mnt_flags \|= MNT_READONLY \| MNT_NOATIME;

		ufs->lower_layers[ufs->numlower].mnt = mnt;
		ufs->lower_layers[ufs->numlower].pseudo_dev = dev;
		ufs->numlower++;

		/* Check if all lower layers are on same sb */
		if (i == 0)
		ufs->same_sb = mnt->mnt_sb;
		else if (ufs->same_sb != mnt->mnt_sb)
		ufs->same_sb = NULL;
		}

		/* If the upper fs is nonexistent, we mark overlayfs r/o too */
		if (!ufs->upper_mnt)

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