ovl: resolve more conflicting mount options (b0def88d) · Commits · 戴 / test

Documentation/filesystems/overlayfs.rst

+5 −2

Original line number	Diff line number	Diff line
		@@ -365,8 +365,8 @@ pointed by REDIRECT. This should not be possible on local system as setting
		"trusted." xattrs will require CAP_SYS_ADMIN. But it should be possible
		for untrusted layers like from a pen drive.

		Note: redirect_dir={off\|nofollow\|follow[*]} conflicts with metacopy=on, and
		results in an error.
		Note: redirect_dir={off\|nofollow\|follow[*]} and nfs_export=on mount options
		conflict with metacopy=on, and will result in an error.

		[*] redirect_dir=follow only conflicts with metacopy=on if upperdir=... is
		given.
		@@ -560,6 +560,9 @@ When the NFS export feature is enabled, all directory index entries are
		verified on mount time to check that upper file handles are not stale.
		This verification may cause significant overhead in some cases.

		Note: the mount options index=off,nfs_export=on are conflicting and will
		result in an error.


		Testsuite
		---------

fs/overlayfs/super.c

+48 −0

Original line number	Diff line number	Diff line
		@@ -470,6 +470,7 @@ static int ovl_parse_opt(char opt, struct ovl_config config)
		char *p;
		int err;
		bool metacopy_opt = false, redirect_opt = false;
		bool nfs_export_opt = false, index_opt = false;

		config->redirect_mode = kstrdup(ovl_redirect_mode_def(), GFP_KERNEL);
		if (!config->redirect_mode)
		@@ -519,18 +520,22 @@ static int ovl_parse_opt(char opt, struct ovl_config config)

		case OPT_INDEX_ON:
		config->index = true;
		index_opt = true;
		break;

		case OPT_INDEX_OFF:
		config->index = false;
		index_opt = true;
		break;

		case OPT_NFS_EXPORT_ON:
		config->nfs_export = true;
		nfs_export_opt = true;
		break;

		case OPT_NFS_EXPORT_OFF:
		config->nfs_export = false;
		nfs_export_opt = true;
		break;

		case OPT_XINO_ON:
		@@ -552,6 +557,7 @@ static int ovl_parse_opt(char opt, struct ovl_config config)

		case OPT_METACOPY_OFF:
		config->metacopy = false;
		metacopy_opt = true;
		break;

		default:
		@@ -601,6 +607,48 @@ static int ovl_parse_opt(char opt, struct ovl_config config)
		}
		}

		/* Resolve nfs_export -> index dependency */
		if (config->nfs_export && !config->index) {
		if (nfs_export_opt && index_opt) {
		pr_err("conflicting options: nfs_export=on,index=off\n");
		return -EINVAL;
		}
		if (index_opt) {
		/*
		* There was an explicit index=off that resulted
		* in this conflict.
		*/
		pr_info("disabling nfs_export due to index=off\n");
		config->nfs_export = false;
		} else {
		/* Automatically enable index otherwise. */
		config->index = true;
		}
		}

		/* Resolve nfs_export -> !metacopy dependency */
		if (config->nfs_export && config->metacopy) {
		if (nfs_export_opt && metacopy_opt) {
		pr_err("conflicting options: nfs_export=on,metacopy=on\n");
		return -EINVAL;
		}
		if (metacopy_opt) {
		/*
		* There was an explicit metacopy=on that resulted
		* in this conflict.
		*/
		pr_info("disabling nfs_export due to metacopy=on\n");
		config->nfs_export = false;
		} else {
		/*
		* There was an explicit nfs_export=on that resulted
		* in this conflict.
		*/
		pr_info("disabling metacopy due to nfs_export=on\n");
		config->metacopy = false;
		}
		}

		return 0;
		}

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