ovl: split out ovl_get_lowerstack() from ovl_fill_super() (53dbb0b4) · Commits · 戴 / test

fs/overlayfs/super.c

+72 −50

Original line number	Diff line number	Diff line
		@@ -895,6 +895,75 @@ out:
		return err;
		}

		static int ovl_get_lowerstack(struct super_block sb, struct ovl_fs ufs,
		struct path *stackp, unsigned int stacklenp)
		{
		int err;
		char lowertmp, lower;
		struct path *stack;
		unsigned int stacklen, numlower, i;
		bool remote = false;

		err = -ENOMEM;
		lowertmp = kstrdup(ufs->config.lowerdir, GFP_KERNEL);
		if (!lowertmp)
		goto out;

		err = -EINVAL;
		stacklen = ovl_split_lowerdirs(lowertmp);
		if (stacklen > OVL_MAX_STACK) {
		pr_err("overlayfs: too many lower directories, limit is %d\n",
		OVL_MAX_STACK);
		goto out;
		} else if (!ufs->config.upperdir && stacklen == 1) {
		pr_err("overlayfs: at least 2 lowerdir are needed while upperdir nonexistent\n");
		goto out;
		}

		err = -ENOMEM;
		stack = kcalloc(stacklen, sizeof(struct path), GFP_KERNEL);
		if (!stack)
		goto out;

		err = -EINVAL;
		lower = lowertmp;
		for (numlower = 0; numlower < stacklen; numlower++) {
		err = ovl_lower_dir(lower, &stack[numlower], ufs,
		&sb->s_stack_depth, &remote);
		if (err)
		goto out_free_stack;

		lower = strchr(lower, '\0') + 1;
		}

		err = -EINVAL;
		sb->s_stack_depth++;
		if (sb->s_stack_depth > FILESYSTEM_MAX_STACK_DEPTH) {
		pr_err("overlayfs: maximum fs stacking depth exceeded\n");
		goto out_free_stack;
		}

		*stackp = stack;
		*stacklenp = numlower;

		if (remote)
		sb->s_d_op = &ovl_reval_dentry_operations;
		else
		sb->s_d_op = &ovl_dentry_operations;

		err = 0;

		out:
		kfree(lowertmp);
		return err;

		out_free_stack:
		for (i = 0; i < numlower; i++)
		path_put(&stack[i]);
		kfree(stack);
		goto out;
		}

		static int ovl_fill_super(struct super_block sb, void data, int silent)
		{
		struct path upperpath = { };
		@@ -903,12 +972,8 @@ static int ovl_fill_super(struct super_block sb, void data, int silent)
		struct ovl_entry *oe;
		struct ovl_fs *ufs;
		struct path *stack = NULL;
		char *lowertmp;
		char *lower;
		unsigned int numlower;
		unsigned int stacklen = 0;
		unsigned int numlower = 0;
		unsigned int i;
		bool remote = false;
		struct cred *cred;
		int err;

		@@ -948,44 +1013,9 @@ static int ovl_fill_super(struct super_block sb, void data, int silent)

		sb->s_stack_depth = upperpath.mnt->mnt_sb->s_stack_depth;
		}
		err = -ENOMEM;
		lowertmp = kstrdup(ufs->config.lowerdir, GFP_KERNEL);
		if (!lowertmp)
		goto out_unlock_workdentry;

		err = -EINVAL;
		stacklen = ovl_split_lowerdirs(lowertmp);
		if (stacklen > OVL_MAX_STACK) {
		pr_err("overlayfs: too many lower directories, limit is %d\n",
		OVL_MAX_STACK);
		goto out_free_lowertmp;
		} else if (!ufs->config.upperdir && stacklen == 1) {
		pr_err("overlayfs: at least 2 lowerdir are needed while upperdir nonexistent\n");
		goto out_free_lowertmp;
		}

		err = -ENOMEM;
		stack = kcalloc(stacklen, sizeof(struct path), GFP_KERNEL);
		if (!stack)
		goto out_free_lowertmp;

		err = -EINVAL;
		lower = lowertmp;
		for (numlower = 0; numlower < stacklen; numlower++) {
		err = ovl_lower_dir(lower, &stack[numlower], ufs,
		&sb->s_stack_depth, &remote);
		err = ovl_get_lowerstack(sb, ufs, &stack, &numlower);
		if (err)
		goto out_put_lowerpath;

		lower = strchr(lower, '\0') + 1;
		}

		err = -EINVAL;
		sb->s_stack_depth++;
		if (sb->s_stack_depth > FILESYSTEM_MAX_STACK_DEPTH) {
		pr_err("overlayfs: maximum fs stacking depth exceeded\n");
		goto out_put_lowerpath;
		}
		goto out_unlock_workdentry;

		if (ufs->config.upperdir) {
		ufs->upper_mnt = clone_private_mount(&upperpath);
		@@ -1145,11 +1175,6 @@ static int ovl_fill_super(struct super_block sb, void data, int silent)
		if (!ufs->indexdir)
		ufs->config.index = false;

		if (remote)
		sb->s_d_op = &ovl_reval_dentry_operations;
		else
		sb->s_d_op = &ovl_dentry_operations;

		err = -ENOMEM;
		ufs->creator_cred = cred = prepare_creds();
		if (!cred)
		@@ -1173,7 +1198,6 @@ static int ovl_fill_super(struct super_block sb, void data, int silent)
		mntput(stack[i].mnt);
		kfree(stack);
		mntput(workpath.mnt);
		kfree(lowertmp);

		if (upperpath.dentry) {
		oe->has_upper = true;
		@@ -1212,8 +1236,6 @@ out_put_lowerpath:
		for (i = 0; i < numlower; i++)
		path_put(&stack[i]);
		kfree(stack);
		out_free_lowertmp:
		kfree(lowertmp);
		out_unlock_workdentry:
		if (ufs->workdir_locked)
		ovl_inuse_unlock(workpath.dentry);

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