Merge branch 'overlayfs-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs (f28929ba) · Commits · e / devices / android_kernel_teracube_emerald

Documentation/filesystems/overlayfs.txt

+3 −5

Original line number	Original line	Diff line number	Diff line
	@@ -183,12 +183,10 @@ The copy_up operation essentially creates a new, identical file and
	moves it over to the old name. The new file may be on a different		moves it over to the old name. The new file may be on a different
	filesystem, so both st_dev and st_ino of the file may change.		filesystem, so both st_dev and st_ino of the file may change.

	Any open files referring to this inode will access the old data and		Any open files referring to this inode will access the old data.
	metadata. Similarly any file locks obtained before copy_up will not
	apply to the copied up file.

	On a file opened with O_RDONLY fchmod(2), fchown(2), futimesat(2) and		Any file locks (and leases) obtained before copy_up will not apply
	fsetxattr(2) will fail with EROFS.		to the copied up file.

	If a file with multiple hard links is copied up, then this will		If a file with multiple hard links is copied up, then this will
	"break" the link. Changes will not be propagated to other names		"break" the link. Changes will not be propagated to other names

fs/overlayfs/copy_up.c

+2 −0

Original line number	Original line	Diff line number	Diff line
	@@ -80,6 +80,8 @@ int ovl_copy_xattr(struct dentry old, struct dentry new)
	}		}

	for (name = buf; name < (buf + list_size); name += strlen(name) + 1) {		for (name = buf; name < (buf + list_size); name += strlen(name) + 1) {
			if (ovl_is_private_xattr(name))
			continue;
	retry:		retry:
	size = vfs_getxattr(old, name, value, value_size);		size = vfs_getxattr(old, name, value, value_size);
	if (size == -ERANGE)		if (size == -ERANGE)

fs/overlayfs/dir.c

+56 −2

Original line number	Original line	Diff line number	Diff line
	@@ -12,6 +12,8 @@
	#include <linux/xattr.h>		#include <linux/xattr.h>
	#include <linux/security.h>		#include <linux/security.h>
	#include <linux/cred.h>		#include <linux/cred.h>
			#include <linux/posix_acl.h>
			#include <linux/posix_acl_xattr.h>
	#include "overlayfs.h"		#include "overlayfs.h"

	void ovl_cleanup(struct inode wdir, struct dentry wdentry)		void ovl_cleanup(struct inode wdir, struct dentry wdentry)
	@@ -186,6 +188,9 @@ static int ovl_create_upper(struct dentry dentry, struct inode inode,
	struct dentry *newdentry;		struct dentry *newdentry;
	int err;		int err;

			if (!hardlink && !IS_POSIXACL(udir))
			stat->mode &= ~current_umask();

	inode_lock_nested(udir, I_MUTEX_PARENT);		inode_lock_nested(udir, I_MUTEX_PARENT);
	newdentry = lookup_one_len(dentry->d_name.name, upperdir,		newdentry = lookup_one_len(dentry->d_name.name, upperdir,
	dentry->d_name.len);		dentry->d_name.len);
	@@ -335,6 +340,32 @@ static struct dentry ovl_check_empty_and_clear(struct dentry dentry)
	return ret;		return ret;
	}		}

			static int ovl_set_upper_acl(struct dentry upperdentry, const char name,
			const struct posix_acl *acl)
			{
			void *buffer;
			size_t size;
			int err;

			if (!IS_ENABLED(CONFIG_FS_POSIX_ACL) \|\| !acl)
			return 0;

			size = posix_acl_to_xattr(NULL, acl, NULL, 0);
			buffer = kmalloc(size, GFP_KERNEL);
			if (!buffer)
			return -ENOMEM;

			size = posix_acl_to_xattr(&init_user_ns, acl, buffer, size);
			err = size;
			if (err < 0)
			goto out_free;

			err = vfs_setxattr(upperdentry, name, buffer, size, XATTR_CREATE);
			out_free:
			kfree(buffer);
			return err;
			}

	static int ovl_create_over_whiteout(struct dentry dentry, struct inode inode,		static int ovl_create_over_whiteout(struct dentry dentry, struct inode inode,
	struct kstat stat, const char link,		struct kstat stat, const char link,
	struct dentry *hardlink)		struct dentry *hardlink)
	@@ -346,10 +377,18 @@ static int ovl_create_over_whiteout(struct dentry dentry, struct inode inode,
	struct dentry *upper;		struct dentry *upper;
	struct dentry *newdentry;		struct dentry *newdentry;
	int err;		int err;
			struct posix_acl acl, default_acl;

	if (WARN_ON(!workdir))		if (WARN_ON(!workdir))
	return -EROFS;		return -EROFS;

			if (!hardlink) {
			err = posix_acl_create(dentry->d_parent->d_inode,
			&stat->mode, &default_acl, &acl);
			if (err)
			return err;
			}

	err = ovl_lock_rename_workdir(workdir, upperdir);		err = ovl_lock_rename_workdir(workdir, upperdir);
	if (err)		if (err)
	goto out;		goto out;
	@@ -384,6 +423,17 @@ static int ovl_create_over_whiteout(struct dentry dentry, struct inode inode,
	if (err)		if (err)
	goto out_cleanup;		goto out_cleanup;
	}		}
			if (!hardlink) {
			err = ovl_set_upper_acl(newdentry, XATTR_NAME_POSIX_ACL_ACCESS,
			acl);
			if (err)
			goto out_cleanup;

			err = ovl_set_upper_acl(newdentry, XATTR_NAME_POSIX_ACL_DEFAULT,
			default_acl);
			if (err)
			goto out_cleanup;
			}

	if (!hardlink && S_ISDIR(stat->mode)) {		if (!hardlink && S_ISDIR(stat->mode)) {
	err = ovl_set_opaque(newdentry);		err = ovl_set_opaque(newdentry);
	@@ -410,6 +460,10 @@ static int ovl_create_over_whiteout(struct dentry dentry, struct inode inode,
	out_unlock:		out_unlock:
	unlock_rename(workdir, upperdir);		unlock_rename(workdir, upperdir);
	out:		out:
			if (!hardlink) {
			posix_acl_release(acl);
			posix_acl_release(default_acl);
			}
	return err;		return err;

	out_cleanup:		out_cleanup:
	@@ -950,9 +1004,9 @@ const struct inode_operations ovl_dir_inode_operations = {
	.permission = ovl_permission,		.permission = ovl_permission,
	.getattr = ovl_dir_getattr,		.getattr = ovl_dir_getattr,
	.setxattr = generic_setxattr,		.setxattr = generic_setxattr,
	.getxattr = ovl_getxattr,		.getxattr = generic_getxattr,
	.listxattr = ovl_listxattr,		.listxattr = ovl_listxattr,
	.removexattr = ovl_removexattr,		.removexattr = generic_removexattr,
	.get_acl = ovl_get_acl,		.get_acl = ovl_get_acl,
	.update_time = ovl_update_time,		.update_time = ovl_update_time,
	};		};

fs/overlayfs/inode.c

+44 −64

Original line number	Original line	Diff line number	Diff line
	@@ -10,6 +10,7 @@
	#include <linux/fs.h>		#include <linux/fs.h>
	#include <linux/slab.h>		#include <linux/slab.h>
	#include <linux/xattr.h>		#include <linux/xattr.h>
			#include <linux/posix_acl.h>
	#include "overlayfs.h"		#include "overlayfs.h"

	static int ovl_copy_up_truncate(struct dentry *dentry)		static int ovl_copy_up_truncate(struct dentry *dentry)
	@@ -191,32 +192,44 @@ static int ovl_readlink(struct dentry dentry, char __user buf, int bufsiz)
	return err;		return err;
	}		}

	static bool ovl_is_private_xattr(const char *name)		bool ovl_is_private_xattr(const char *name)
	{		{
	#define OVL_XATTR_PRE_NAME OVL_XATTR_PREFIX "."		return strncmp(name, OVL_XATTR_PREFIX,
	return strncmp(name, OVL_XATTR_PRE_NAME,		sizeof(OVL_XATTR_PREFIX) - 1) == 0;
	sizeof(OVL_XATTR_PRE_NAME) - 1) == 0;
	}		}

	int ovl_setxattr(struct dentry dentry, struct inode inode,		int ovl_xattr_set(struct dentry dentry, const char name, const void *value,
	const char name, const void value,
	size_t size, int flags)		size_t size, int flags)
	{		{
	int err;		int err;
	struct dentry *upperdentry;		struct path realpath;
			enum ovl_path_type type = ovl_path_real(dentry, &realpath);
	const struct cred *old_cred;		const struct cred *old_cred;

	err = ovl_want_write(dentry);		err = ovl_want_write(dentry);
	if (err)		if (err)
	goto out;		goto out;

			if (!value && !OVL_TYPE_UPPER(type)) {
			err = vfs_getxattr(realpath.dentry, name, NULL, 0);
			if (err < 0)
			goto out_drop_write;
			}

	err = ovl_copy_up(dentry);		err = ovl_copy_up(dentry);
	if (err)		if (err)
	goto out_drop_write;		goto out_drop_write;

	upperdentry = ovl_dentry_upper(dentry);		if (!OVL_TYPE_UPPER(type))
			ovl_path_upper(dentry, &realpath);

	old_cred = ovl_override_creds(dentry->d_sb);		old_cred = ovl_override_creds(dentry->d_sb);
	err = vfs_setxattr(upperdentry, name, value, size, flags);		if (value)
			err = vfs_setxattr(realpath.dentry, name, value, size, flags);
			else {
			WARN_ON(flags != XATTR_REPLACE);
			err = vfs_removexattr(realpath.dentry, name);
			}
	revert_creds(old_cred);		revert_creds(old_cred);

	out_drop_write:		out_drop_write:
	@@ -225,16 +238,13 @@ int ovl_setxattr(struct dentry dentry, struct inode inode,
	return err;		return err;
	}		}

	ssize_t ovl_getxattr(struct dentry dentry, struct inode inode,		int ovl_xattr_get(struct dentry dentry, const char name,
	const char name, void value, size_t size)		void *value, size_t size)
	{		{
	struct dentry *realdentry = ovl_dentry_real(dentry);		struct dentry *realdentry = ovl_dentry_real(dentry);
	ssize_t res;		ssize_t res;
	const struct cred *old_cred;		const struct cred *old_cred;

	if (ovl_is_private_xattr(name))
	return -ENODATA;

	old_cred = ovl_override_creds(dentry->d_sb);		old_cred = ovl_override_creds(dentry->d_sb);
	res = vfs_getxattr(realdentry, name, value, size);		res = vfs_getxattr(realdentry, name, value, size);
	revert_creds(old_cred);		revert_creds(old_cred);
	@@ -245,7 +255,8 @@ ssize_t ovl_listxattr(struct dentry dentry, char list, size_t size)
	{		{
	struct dentry *realdentry = ovl_dentry_real(dentry);		struct dentry *realdentry = ovl_dentry_real(dentry);
	ssize_t res;		ssize_t res;
	int off;		size_t len;
			char *s;
	const struct cred *old_cred;		const struct cred *old_cred;

	old_cred = ovl_override_creds(dentry->d_sb);		old_cred = ovl_override_creds(dentry->d_sb);
	@@ -255,73 +266,39 @@ ssize_t ovl_listxattr(struct dentry dentry, char list, size_t size)
	return res;		return res;

	/* filter out private xattrs */		/* filter out private xattrs */
	for (off = 0; off < res;) {		for (s = list, len = res; len;) {
	char *s = list + off;		size_t slen = strnlen(s, len) + 1;
	size_t slen = strlen(s) + 1;

	BUG_ON(off + slen > res);		/* underlying fs providing us with an broken xattr list? */
			if (WARN_ON(slen > len))
			return -EIO;

			len -= slen;
	if (ovl_is_private_xattr(s)) {		if (ovl_is_private_xattr(s)) {
	res -= slen;		res -= slen;
	memmove(s, s + slen, res - off);		memmove(s, s + slen, len);
	} else {		} else {
	off += slen;		s += slen;
	}		}
	}		}

	return res;		return res;
	}		}

	int ovl_removexattr(struct dentry dentry, const char name)
	{
	int err;
	struct path realpath;
	enum ovl_path_type type = ovl_path_real(dentry, &realpath);
	const struct cred *old_cred;

	err = ovl_want_write(dentry);
	if (err)
	goto out;

	err = -ENODATA;
	if (ovl_is_private_xattr(name))
	goto out_drop_write;

	if (!OVL_TYPE_UPPER(type)) {
	err = vfs_getxattr(realpath.dentry, name, NULL, 0);
	if (err < 0)
	goto out_drop_write;

	err = ovl_copy_up(dentry);
	if (err)
	goto out_drop_write;

	ovl_path_upper(dentry, &realpath);
	}

	old_cred = ovl_override_creds(dentry->d_sb);
	err = vfs_removexattr(realpath.dentry, name);
	revert_creds(old_cred);
	out_drop_write:
	ovl_drop_write(dentry);
	out:
	return err;
	}

	struct posix_acl ovl_get_acl(struct inode inode, int type)		struct posix_acl ovl_get_acl(struct inode inode, int type)
	{		{
	struct inode *realinode = ovl_inode_real(inode, NULL);		struct inode *realinode = ovl_inode_real(inode, NULL);
	const struct cred *old_cred;		const struct cred *old_cred;
	struct posix_acl *acl;		struct posix_acl *acl;

	if (!IS_POSIXACL(realinode))		if (!IS_ENABLED(CONFIG_FS_POSIX_ACL) \|\| !IS_POSIXACL(realinode))
	return NULL;		return NULL;

	if (!realinode->i_op->get_acl)		if (!realinode->i_op->get_acl)
	return NULL;		return NULL;

	old_cred = ovl_override_creds(inode->i_sb);		old_cred = ovl_override_creds(inode->i_sb);
	acl = realinode->i_op->get_acl(realinode, type);		acl = get_acl(realinode, type);
	revert_creds(old_cred);		revert_creds(old_cred);

	return acl;		return acl;
	@@ -391,9 +368,9 @@ static const struct inode_operations ovl_file_inode_operations = {
	.permission = ovl_permission,		.permission = ovl_permission,
	.getattr = ovl_getattr,		.getattr = ovl_getattr,
	.setxattr = generic_setxattr,		.setxattr = generic_setxattr,
	.getxattr = ovl_getxattr,		.getxattr = generic_getxattr,
	.listxattr = ovl_listxattr,		.listxattr = ovl_listxattr,
	.removexattr = ovl_removexattr,		.removexattr = generic_removexattr,
	.get_acl = ovl_get_acl,		.get_acl = ovl_get_acl,
	.update_time = ovl_update_time,		.update_time = ovl_update_time,
	};		};
	@@ -404,9 +381,9 @@ static const struct inode_operations ovl_symlink_inode_operations = {
	.readlink = ovl_readlink,		.readlink = ovl_readlink,
	.getattr = ovl_getattr,		.getattr = ovl_getattr,
	.setxattr = generic_setxattr,		.setxattr = generic_setxattr,
	.getxattr = ovl_getxattr,		.getxattr = generic_getxattr,
	.listxattr = ovl_listxattr,		.listxattr = ovl_listxattr,
	.removexattr = ovl_removexattr,		.removexattr = generic_removexattr,
	.update_time = ovl_update_time,		.update_time = ovl_update_time,
	};		};

	@@ -415,6 +392,9 @@ static void ovl_fill_inode(struct inode *inode, umode_t mode)
	inode->i_ino = get_next_ino();		inode->i_ino = get_next_ino();
	inode->i_mode = mode;		inode->i_mode = mode;
	inode->i_flags \|= S_NOCMTIME;		inode->i_flags \|= S_NOCMTIME;
			#ifdef CONFIG_FS_POSIX_ACL
			inode->i_acl = inode->i_default_acl = ACL_DONT_CACHE;
			#endif

	mode &= S_IFMT;		mode &= S_IFMT;
	switch (mode) {		switch (mode) {

fs/overlayfs/overlayfs.h

+9 −8

Original line number	Original line	Diff line number	Diff line
	@@ -24,8 +24,8 @@ enum ovl_path_type {
	(OVL_TYPE_MERGE(type) \|\| !OVL_TYPE_UPPER(type))		(OVL_TYPE_MERGE(type) \|\| !OVL_TYPE_UPPER(type))


	#define OVL_XATTR_PREFIX XATTR_TRUSTED_PREFIX "overlay"		#define OVL_XATTR_PREFIX XATTR_TRUSTED_PREFIX "overlay."
	#define OVL_XATTR_OPAQUE OVL_XATTR_PREFIX ".opaque"		#define OVL_XATTR_OPAQUE OVL_XATTR_PREFIX "opaque"

	#define OVL_ISUPPER_MASK 1UL		#define OVL_ISUPPER_MASK 1UL

	@@ -179,20 +179,21 @@ int ovl_check_empty_dir(struct dentry dentry, struct list_head list);
	void ovl_cleanup_whiteouts(struct dentry upper, struct list_head list);		void ovl_cleanup_whiteouts(struct dentry upper, struct list_head list);
	void ovl_cache_free(struct list_head *list);		void ovl_cache_free(struct list_head *list);
	int ovl_check_d_type_supported(struct path *realpath);		int ovl_check_d_type_supported(struct path *realpath);
			void ovl_workdir_cleanup(struct inode dir, struct vfsmount mnt,
			struct dentry *dentry, int level);

	/* inode.c */		/* inode.c */
	int ovl_setattr(struct dentry dentry, struct iattr attr);		int ovl_setattr(struct dentry dentry, struct iattr attr);
	int ovl_permission(struct inode *inode, int mask);		int ovl_permission(struct inode *inode, int mask);
	int ovl_setxattr(struct dentry dentry, struct inode inode,		int ovl_xattr_set(struct dentry dentry, const char name, const void *value,
	const char name, const void value,
	size_t size, int flags);		size_t size, int flags);
	ssize_t ovl_getxattr(struct dentry dentry, struct inode inode,		int ovl_xattr_get(struct dentry dentry, const char name,
	const char name, void value, size_t size);		void *value, size_t size);
	ssize_t ovl_listxattr(struct dentry dentry, char list, size_t size);		ssize_t ovl_listxattr(struct dentry dentry, char list, size_t size);
	int ovl_removexattr(struct dentry dentry, const char name);
	struct posix_acl ovl_get_acl(struct inode inode, int type);		struct posix_acl ovl_get_acl(struct inode inode, int type);
	int ovl_open_maybe_copy_up(struct dentry *dentry, unsigned int file_flags);		int ovl_open_maybe_copy_up(struct dentry *dentry, unsigned int file_flags);
	int ovl_update_time(struct inode inode, struct timespec ts, int flags);		int ovl_update_time(struct inode inode, struct timespec ts, int flags);
			bool ovl_is_private_xattr(const char *name);

	struct inode ovl_new_inode(struct super_block sb, umode_t mode);		struct inode ovl_new_inode(struct super_block sb, umode_t mode);
	struct inode ovl_get_inode(struct super_block sb, struct inode *realinode);		struct inode ovl_get_inode(struct super_block sb, struct inode *realinode);