Merge branch 'overlayfs-next' of... (ce7b9fac) · Commits · e / devices / android_kernel_teracube_2e

Documentation/filesystems/overlayfs.txt

+28 −0

Original line number	Original line	Diff line number	Diff line
	@@ -159,6 +159,22 @@ overlay filesystem (though an operation on the name of the file such as
	rename or unlink will of course be noticed and handled).		rename or unlink will of course be noticed and handled).


			Multiple lower layers
			---------------------

			Multiple lower layers can now be given using the the colon (":") as a
			separator character between the directory names. For example:

			mount -t overlay overlay -olowerdir=/lower1:/lower2:/lower3 /merged

			As the example shows, "upperdir=" and "workdir=" may be omitted. In
			that case the overlay will be read-only.

			The specified lower directories will be stacked beginning from the
			rightmost one and going left. In the above example lower1 will be the
			top, lower2 the middle and lower3 the bottom layer.


	Non-standard behavior		Non-standard behavior
	---------------------		---------------------

	@@ -196,3 +212,15 @@ Changes to the underlying filesystems while part of a mounted overlay
	filesystem are not allowed. If the underlying filesystem is changed,		filesystem are not allowed. If the underlying filesystem is changed,
	the behavior of the overlay is undefined, though it will not result in		the behavior of the overlay is undefined, though it will not result in
	a crash or deadlock.		a crash or deadlock.

			Testsuite
			---------

			There's testsuite developed by David Howells at:

			git://git.infradead.org/users/dhowells/unionmount-testsuite.git

			Run as root:

			# cd unionmount-testsuite
			# ./run --ov

fs/overlayfs/copy_up.c

+2 −3

Original line number	Original line	Diff line number	Diff line
	@@ -191,7 +191,6 @@ int ovl_set_attr(struct dentry upperdentry, struct kstat stat)
	ovl_set_timestamps(upperdentry, stat);		ovl_set_timestamps(upperdentry, stat);

	return err;		return err;

	}		}

	static int ovl_copy_up_locked(struct dentry workdir, struct dentry upperdir,		static int ovl_copy_up_locked(struct dentry workdir, struct dentry upperdir,
	@@ -385,7 +384,7 @@ int ovl_copy_up(struct dentry *dentry)
	struct kstat stat;		struct kstat stat;
	enum ovl_path_type type = ovl_path_type(dentry);		enum ovl_path_type type = ovl_path_type(dentry);

	if (type != OVL_PATH_LOWER)		if (OVL_TYPE_UPPER(type))
	break;		break;

	next = dget(dentry);		next = dget(dentry);
	@@ -394,7 +393,7 @@ int ovl_copy_up(struct dentry *dentry)
	parent = dget_parent(next);		parent = dget_parent(next);

	type = ovl_path_type(parent);		type = ovl_path_type(parent);
	if (type != OVL_PATH_LOWER)		if (OVL_TYPE_UPPER(type))
	break;		break;

	dput(next);		dput(next);

fs/overlayfs/dir.c

+14 −14

Original line number	Original line	Diff line number	Diff line
	@@ -118,14 +118,14 @@ int ovl_create_real(struct inode dir, struct dentry newdentry,

	static int ovl_set_opaque(struct dentry *upperdentry)		static int ovl_set_opaque(struct dentry *upperdentry)
	{		{
	return ovl_do_setxattr(upperdentry, ovl_opaque_xattr, "y", 1, 0);		return ovl_do_setxattr(upperdentry, OVL_XATTR_OPAQUE, "y", 1, 0);
	}		}

	static void ovl_remove_opaque(struct dentry *upperdentry)		static void ovl_remove_opaque(struct dentry *upperdentry)
	{		{
	int err;		int err;

	err = ovl_do_removexattr(upperdentry, ovl_opaque_xattr);		err = ovl_do_removexattr(upperdentry, OVL_XATTR_OPAQUE);
	if (err) {		if (err) {
	pr_warn("overlayfs: failed to remove opaque from '%s' (%i)\n",		pr_warn("overlayfs: failed to remove opaque from '%s' (%i)\n",
	upperdentry->d_name.name, err);		upperdentry->d_name.name, err);
	@@ -152,7 +152,7 @@ static int ovl_dir_getattr(struct vfsmount mnt, struct dentry dentry,
	* correct link count. nlink=1 seems to pacify 'find' and		* correct link count. nlink=1 seems to pacify 'find' and
	* other utilities.		* other utilities.
	*/		*/
	if (type == OVL_PATH_MERGE)		if (OVL_TYPE_MERGE(type))
	stat->nlink = 1;		stat->nlink = 1;

	return 0;		return 0;
	@@ -506,7 +506,7 @@ static int ovl_remove_and_whiteout(struct dentry *dentry, bool is_dir)
	struct dentry *opaquedir = NULL;		struct dentry *opaquedir = NULL;
	int err;		int err;

	if (is_dir) {		if (is_dir && OVL_TYPE_MERGE_OR_LOWER(ovl_path_type(dentry))) {
	opaquedir = ovl_check_empty_and_clear(dentry);		opaquedir = ovl_check_empty_and_clear(dentry);
	err = PTR_ERR(opaquedir);		err = PTR_ERR(opaquedir);
	if (IS_ERR(opaquedir))		if (IS_ERR(opaquedir))
	@@ -630,7 +630,7 @@ static int ovl_do_remove(struct dentry *dentry, bool is_dir)
	goto out_drop_write;		goto out_drop_write;

	type = ovl_path_type(dentry);		type = ovl_path_type(dentry);
	if (type == OVL_PATH_PURE_UPPER) {		if (OVL_TYPE_PURE_UPPER(type)) {
	err = ovl_remove_upper(dentry, is_dir);		err = ovl_remove_upper(dentry, is_dir);
	} else {		} else {
	const struct cred *old_cred;		const struct cred *old_cred;
	@@ -712,7 +712,7 @@ static int ovl_rename2(struct inode olddir, struct dentry old,
	/* Don't copy up directory trees */		/* Don't copy up directory trees */
	old_type = ovl_path_type(old);		old_type = ovl_path_type(old);
	err = -EXDEV;		err = -EXDEV;
	if ((old_type == OVL_PATH_LOWER \|\| old_type == OVL_PATH_MERGE) && is_dir)		if (OVL_TYPE_MERGE_OR_LOWER(old_type) && is_dir)
	goto out;		goto out;

	if (new->d_inode) {		if (new->d_inode) {
	@@ -725,25 +725,25 @@ static int ovl_rename2(struct inode olddir, struct dentry old,

	new_type = ovl_path_type(new);		new_type = ovl_path_type(new);
	err = -EXDEV;		err = -EXDEV;
	if (!overwrite && (new_type == OVL_PATH_LOWER \|\| new_type == OVL_PATH_MERGE) && new_is_dir)		if (!overwrite && OVL_TYPE_MERGE_OR_LOWER(new_type) && new_is_dir)
	goto out;		goto out;

	err = 0;		err = 0;
	if (new_type == OVL_PATH_LOWER && old_type == OVL_PATH_LOWER) {		if (!OVL_TYPE_UPPER(new_type) && !OVL_TYPE_UPPER(old_type)) {
	if (ovl_dentry_lower(old)->d_inode ==		if (ovl_dentry_lower(old)->d_inode ==
	ovl_dentry_lower(new)->d_inode)		ovl_dentry_lower(new)->d_inode)
	goto out;		goto out;
	}		}
	if (new_type != OVL_PATH_LOWER && old_type != OVL_PATH_LOWER) {		if (OVL_TYPE_UPPER(new_type) && OVL_TYPE_UPPER(old_type)) {
	if (ovl_dentry_upper(old)->d_inode ==		if (ovl_dentry_upper(old)->d_inode ==
	ovl_dentry_upper(new)->d_inode)		ovl_dentry_upper(new)->d_inode)
	goto out;		goto out;
	}		}
	} else {		} else {
	if (ovl_dentry_is_opaque(new))		if (ovl_dentry_is_opaque(new))
	new_type = OVL_PATH_UPPER;		new_type = __OVL_PATH_UPPER;
	else		else
	new_type = OVL_PATH_PURE_UPPER;		new_type = __OVL_PATH_UPPER \| __OVL_PATH_PURE;
	}		}

	err = ovl_want_write(old);		err = ovl_want_write(old);
	@@ -763,8 +763,8 @@ static int ovl_rename2(struct inode olddir, struct dentry old,
	goto out_drop_write;		goto out_drop_write;
	}		}

	old_opaque = old_type != OVL_PATH_PURE_UPPER;		old_opaque = !OVL_TYPE_PURE_UPPER(old_type);
	new_opaque = new_type != OVL_PATH_PURE_UPPER;		new_opaque = !OVL_TYPE_PURE_UPPER(new_type);

	if (old_opaque \|\| new_opaque) {		if (old_opaque \|\| new_opaque) {
	err = -ENOMEM;		err = -ENOMEM;
	@@ -787,7 +787,7 @@ static int ovl_rename2(struct inode olddir, struct dentry old,
	old_cred = override_creds(override_cred);		old_cred = override_creds(override_cred);
	}		}

	if (overwrite && (new_type == OVL_PATH_LOWER \|\| new_type == OVL_PATH_MERGE) && new_is_dir) {		if (overwrite && OVL_TYPE_MERGE_OR_LOWER(new_type) && new_is_dir) {
	opaquedir = ovl_check_empty_and_clear(new);		opaquedir = ovl_check_empty_and_clear(new);
	err = PTR_ERR(opaquedir);		err = PTR_ERR(opaquedir);
	if (IS_ERR(opaquedir)) {		if (IS_ERR(opaquedir)) {

fs/overlayfs/inode.c

+7 −5

Original line number	Original line	Diff line number	Diff line
	@@ -205,7 +205,7 @@ static int ovl_readlink(struct dentry dentry, char __user buf, int bufsiz)

	static bool ovl_is_private_xattr(const char *name)		static bool ovl_is_private_xattr(const char *name)
	{		{
	return strncmp(name, "trusted.overlay.", 14) == 0;		return strncmp(name, OVL_XATTR_PRE_NAME, OVL_XATTR_PRE_LEN) == 0;
	}		}

	int ovl_setxattr(struct dentry dentry, const char name,		int ovl_setxattr(struct dentry dentry, const char name,
	@@ -238,7 +238,10 @@ int ovl_setxattr(struct dentry dentry, const char name,
	static bool ovl_need_xattr_filter(struct dentry *dentry,		static bool ovl_need_xattr_filter(struct dentry *dentry,
	enum ovl_path_type type)		enum ovl_path_type type)
	{		{
	return type == OVL_PATH_UPPER && S_ISDIR(dentry->d_inode->i_mode);		if ((type & (__OVL_PATH_PURE \| __OVL_PATH_UPPER)) == __OVL_PATH_UPPER)
			return S_ISDIR(dentry->d_inode->i_mode);
			else
			return false;
	}		}

	ssize_t ovl_getxattr(struct dentry dentry, const char name,		ssize_t ovl_getxattr(struct dentry dentry, const char name,
	@@ -299,7 +302,7 @@ int ovl_removexattr(struct dentry dentry, const char name)
	if (ovl_need_xattr_filter(dentry, type) && ovl_is_private_xattr(name))		if (ovl_need_xattr_filter(dentry, type) && ovl_is_private_xattr(name))
	goto out_drop_write;		goto out_drop_write;

	if (type == OVL_PATH_LOWER) {		if (!OVL_TYPE_UPPER(type)) {
	err = vfs_getxattr(realpath.dentry, name, NULL, 0);		err = vfs_getxattr(realpath.dentry, name, NULL, 0);
	if (err < 0)		if (err < 0)
	goto out_drop_write;		goto out_drop_write;
	@@ -321,7 +324,7 @@ int ovl_removexattr(struct dentry dentry, const char name)
	static bool ovl_open_need_copy_up(int flags, enum ovl_path_type type,		static bool ovl_open_need_copy_up(int flags, enum ovl_path_type type,
	struct dentry *realdentry)		struct dentry *realdentry)
	{		{
	if (type != OVL_PATH_LOWER)		if (OVL_TYPE_UPPER(type))
	return false;		return false;

	if (special_file(realdentry->d_inode->i_mode))		if (special_file(realdentry->d_inode->i_mode))
	@@ -430,5 +433,4 @@ struct inode ovl_new_inode(struct super_block sb, umode_t mode,
	}		}

	return inode;		return inode;

	}		}

fs/overlayfs/overlayfs.h

+13 −5

Original line number	Original line	Diff line number	Diff line
	@@ -12,13 +12,20 @@
	struct ovl_entry;		struct ovl_entry;

	enum ovl_path_type {		enum ovl_path_type {
	OVL_PATH_PURE_UPPER,		__OVL_PATH_PURE = (1 << 0),
	OVL_PATH_UPPER,		__OVL_PATH_UPPER = (1 << 1),
	OVL_PATH_MERGE,		__OVL_PATH_MERGE = (1 << 2),
	OVL_PATH_LOWER,
	};		};

	extern const char *ovl_opaque_xattr;		#define OVL_TYPE_UPPER(type) ((type) & __OVL_PATH_UPPER)
			#define OVL_TYPE_MERGE(type) ((type) & __OVL_PATH_MERGE)
			#define OVL_TYPE_PURE_UPPER(type) ((type) & __OVL_PATH_PURE)
			#define OVL_TYPE_MERGE_OR_LOWER(type) \
			(OVL_TYPE_MERGE(type) \|\| !OVL_TYPE_UPPER(type))

			#define OVL_XATTR_PRE_NAME "trusted.overlay."
			#define OVL_XATTR_PRE_LEN 16
			#define OVL_XATTR_OPAQUE OVL_XATTR_PRE_NAME"opaque"

	static inline int ovl_do_rmdir(struct inode dir, struct dentry dentry)		static inline int ovl_do_rmdir(struct inode dir, struct dentry dentry)
	{		{
	@@ -130,6 +137,7 @@ void ovl_dentry_version_inc(struct dentry *dentry);
	void ovl_path_upper(struct dentry dentry, struct path path);		void ovl_path_upper(struct dentry dentry, struct path path);
	void ovl_path_lower(struct dentry dentry, struct path path);		void ovl_path_lower(struct dentry dentry, struct path path);
	enum ovl_path_type ovl_path_real(struct dentry dentry, struct path path);		enum ovl_path_type ovl_path_real(struct dentry dentry, struct path path);
			int ovl_path_next(int idx, struct dentry dentry, struct path path);
	struct dentry ovl_dentry_upper(struct dentry dentry);		struct dentry ovl_dentry_upper(struct dentry dentry);
	struct dentry ovl_dentry_lower(struct dentry dentry);		struct dentry ovl_dentry_lower(struct dentry dentry);
	struct dentry ovl_dentry_real(struct dentry dentry);		struct dentry ovl_dentry_real(struct dentry dentry);