f2fs: add xattr and acl functionalities

This implements xattr and acl functionalities.

- F2FS uses a node page to contain use extended attributes.
Signed-off-by: Changman Lee <cm224.lee@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

fs/f2fs/acl.h

+/**
+ * fs/f2fs/acl.h
+ *
+ * Copyright (c) 2012 Samsung Electronics Co., Ltd.
+ *             http://www.samsung.com/
+ *
+ * Portions of this code from linux/fs/ext2/acl.h
+ *
+ * Copyright (C) 2001-2003 Andreas Gruenbacher, <agruen@suse.de>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#ifndef __F2FS_ACL_H__
+#define __F2FS_ACL_H__
+
+#include <linux/posix_acl_xattr.h>
+
+#define F2FS_ACL_VERSION	0x0001
+
+struct f2fs_acl_entry {
+	__le16 e_tag;
+	__le16 e_perm;
+	__le32 e_id;
+};
+
+struct f2fs_acl_entry_short {
+	__le16 e_tag;
+	__le16 e_perm;
+};
+
+struct f2fs_acl_header {
+	__le32 a_version;
+};
+
+#ifdef CONFIG_F2FS_FS_POSIX_ACL
+
+extern struct posix_acl *f2fs_get_acl(struct inode *inode, int type);
+extern int f2fs_acl_chmod(struct inode *inode);
+extern int f2fs_init_acl(struct inode *inode, struct inode *dir);
+#else
+#define f2fs_check_acl	NULL
+#define f2fs_get_acl	NULL
+#define f2fs_set_acl	NULL
+
+static inline int f2fs_acl_chmod(struct inode *inode)
+{
+	return 0;
+}
+
+static inline int f2fs_init_acl(struct inode *inode, struct inode *dir)
+{
+	return 0;
+}
+#endif
+#endif /* __F2FS_ACL_H__ */

fs/f2fs/xattr.c

+/**
+ * fs/f2fs/xattr.c
+ *
+ * Copyright (c) 2012 Samsung Electronics Co., Ltd.
+ *             http://www.samsung.com/
+ *
+ * Portions of this code from linux/fs/ext2/xattr.c
+ *
+ * Copyright (C) 2001-2003 Andreas Gruenbacher <agruen@suse.de>
+ *
+ * Fix by Harrison Xing <harrison@mountainviewdata.com>.
+ * Extended attributes for symlinks and special files added per
+ *  suggestion of Luka Renko <luka.renko@hermes.si>.
+ * xattr consolidation Copyright (c) 2004 James Morris <jmorris@redhat.com>,
+ *  Red Hat Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#include <linux/rwsem.h>
+#include <linux/f2fs_fs.h>
+#include "f2fs.h"
+#include "xattr.h"
+
+static size_t f2fs_xattr_generic_list(struct dentry *dentry, char *list,
+		size_t list_size, const char *name, size_t name_len, int type)
+{
+	struct f2fs_sb_info *sbi = F2FS_SB(dentry->d_sb);
+	int total_len, prefix_len = 0;
+	const char *prefix = NULL;
+
+	switch (type) {
+	case F2FS_XATTR_INDEX_USER:
+		if (!test_opt(sbi, XATTR_USER))
+			return -EOPNOTSUPP;
+		prefix = XATTR_USER_PREFIX;
+		prefix_len = XATTR_USER_PREFIX_LEN;
+		break;
+	case F2FS_XATTR_INDEX_TRUSTED:
+		if (!capable(CAP_SYS_ADMIN))
+			return -EPERM;
+		prefix = XATTR_TRUSTED_PREFIX;
+		prefix_len = XATTR_TRUSTED_PREFIX_LEN;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	total_len = prefix_len + name_len + 1;
+	if (list && total_len <= list_size) {
+		memcpy(list, prefix, prefix_len);
+		memcpy(list+prefix_len, name, name_len);
+		list[prefix_len + name_len] = '\0';
+	}
+	return total_len;
+}
+
+static int f2fs_xattr_generic_get(struct dentry *dentry, const char *name,
+		void *buffer, size_t size, int type)
+{
+	struct f2fs_sb_info *sbi = F2FS_SB(dentry->d_sb);
+
+	switch (type) {
+	case F2FS_XATTR_INDEX_USER:
+		if (!test_opt(sbi, XATTR_USER))
+			return -EOPNOTSUPP;
+		break;
+	case F2FS_XATTR_INDEX_TRUSTED:
+		if (!capable(CAP_SYS_ADMIN))
+			return -EPERM;
+		break;
+	default:
+		return -EINVAL;
+	}
+	if (strcmp(name, "") == 0)
+		return -EINVAL;
+	return f2fs_getxattr(dentry->d_inode, type, name,
+			buffer, size);
+}
+
+static int f2fs_xattr_generic_set(struct dentry *dentry, const char *name,
+		const void *value, size_t size, int flags, int type)
+{
+	struct f2fs_sb_info *sbi = F2FS_SB(dentry->d_sb);
+
+	switch (type) {
+	case F2FS_XATTR_INDEX_USER:
+		if (!test_opt(sbi, XATTR_USER))
+			return -EOPNOTSUPP;
+		break;
+	case F2FS_XATTR_INDEX_TRUSTED:
+		if (!capable(CAP_SYS_ADMIN))
+			return -EPERM;
+		break;
+	default:
+		return -EINVAL;
+	}
+	if (strcmp(name, "") == 0)
+		return -EINVAL;
+
+	return f2fs_setxattr(dentry->d_inode, type, name, value, size);
+}
+
+const struct xattr_handler f2fs_xattr_user_handler = {
+	.prefix	= XATTR_USER_PREFIX,
+	.flags	= F2FS_XATTR_INDEX_USER,
+	.list	= f2fs_xattr_generic_list,
+	.get	= f2fs_xattr_generic_get,
+	.set	= f2fs_xattr_generic_set,
+};
+
+const struct xattr_handler f2fs_xattr_trusted_handler = {
+	.prefix	= XATTR_TRUSTED_PREFIX,
+	.flags	= F2FS_XATTR_INDEX_TRUSTED,
+	.list	= f2fs_xattr_generic_list,
+	.get	= f2fs_xattr_generic_get,
+	.set	= f2fs_xattr_generic_set,
+};
+
+static const struct xattr_handler *f2fs_xattr_handler_map[] = {
+	[F2FS_XATTR_INDEX_USER] = &f2fs_xattr_user_handler,
+#ifdef CONFIG_F2FS_FS_POSIX_ACL
+	[F2FS_XATTR_INDEX_POSIX_ACL_ACCESS] = &f2fs_xattr_acl_access_handler,
+	[F2FS_XATTR_INDEX_POSIX_ACL_DEFAULT] = &f2fs_xattr_acl_default_handler,
+#endif
+	[F2FS_XATTR_INDEX_TRUSTED] = &f2fs_xattr_trusted_handler,
+	[F2FS_XATTR_INDEX_ADVISE] = &f2fs_xattr_advise_handler,
+};
+
+const struct xattr_handler *f2fs_xattr_handlers[] = {
+	&f2fs_xattr_user_handler,
+#ifdef CONFIG_F2FS_FS_POSIX_ACL
+	&f2fs_xattr_acl_access_handler,
+	&f2fs_xattr_acl_default_handler,
+#endif
+	&f2fs_xattr_trusted_handler,
+	&f2fs_xattr_advise_handler,
+	NULL,
+};
+
+static inline const struct xattr_handler *f2fs_xattr_handler(int name_index)
+{
+	const struct xattr_handler *handler = NULL;
+
+	if (name_index > 0 && name_index < ARRAY_SIZE(f2fs_xattr_handler_map))
+		handler = f2fs_xattr_handler_map[name_index];
+	return handler;
+}
+
+int f2fs_getxattr(struct inode *inode, int name_index, const char *name,
+		void *buffer, size_t buffer_size)
+{
+	struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
+	struct f2fs_inode_info *fi = F2FS_I(inode);
+	struct f2fs_xattr_entry *entry;
+	struct page *page;
+	void *base_addr;
+	int error = 0, found = 0;
+	int value_len, name_len;
+
+	if (name == NULL)
+		return -EINVAL;
+	name_len = strlen(name);
+
+	if (!fi->i_xattr_nid)
+		return -ENODATA;
+
+	page = get_node_page(sbi, fi->i_xattr_nid);
+	base_addr = page_address(page);
+
+	list_for_each_xattr(entry, base_addr) {
+		if (entry->e_name_index != name_index)
+			continue;
+		if (entry->e_name_len != name_len)
+			continue;
+		if (!memcmp(entry->e_name, name, name_len)) {
+			found = 1;
+			break;
+		}
+	}
+	if (!found) {
+		error = -ENODATA;
+		goto cleanup;
+	}
+
+	value_len = le16_to_cpu(entry->e_value_size);
+
+	if (buffer && value_len > buffer_size) {
+		error = -ERANGE;
+		goto cleanup;
+	}
+
+	if (buffer) {
+		char *pval = entry->e_name + entry->e_name_len;
+		memcpy(buffer, pval, value_len);
+	}
+	error = value_len;
+
+cleanup:
+	f2fs_put_page(page, 1);
+	return error;
+}
+
+ssize_t f2fs_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size)
+{
+	struct inode *inode = dentry->d_inode;
+	struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
+	struct f2fs_inode_info *fi = F2FS_I(inode);
+	struct f2fs_xattr_entry *entry;
+	struct page *page;
+	void *base_addr;
+	int error = 0;
+	size_t rest = buffer_size;
+
+	if (!fi->i_xattr_nid)
+		return 0;
+
+	page = get_node_page(sbi, fi->i_xattr_nid);
+	base_addr = page_address(page);
+
+	list_for_each_xattr(entry, base_addr) {
+		const struct xattr_handler *handler =
+			f2fs_xattr_handler(entry->e_name_index);
+		size_t size;
+
+		if (!handler)
+			continue;
+
+		size = handler->list(dentry, buffer, rest, entry->e_name,
+				entry->e_name_len, handler->flags);
+		if (buffer && size > rest) {
+			error = -ERANGE;
+			goto cleanup;
+		}
+
+		if (buffer)
+			buffer += size;
+		rest -= size;
+	}
+	error = buffer_size - rest;
+cleanup:
+	f2fs_put_page(page, 1);
+	return error;
+}
+
+int f2fs_setxattr(struct inode *inode, int name_index, const char *name,
+					const void *value, size_t value_len)
+{
+	struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
+	struct f2fs_inode_info *fi = F2FS_I(inode);
+	struct f2fs_xattr_header *header = NULL;
+	struct f2fs_xattr_entry *here, *last;
+	struct page *page;
+	void *base_addr;
+	int error, found, free, name_len, newsize;
+	char *pval;
+
+	if (name == NULL)
+		return -EINVAL;
+	name_len = strlen(name);
+
+	if (value == NULL)
+		value_len = 0;
+
+	if (name_len > 255 || value_len > MAX_VALUE_LEN)
+		return -ERANGE;
+
+	mutex_lock_op(sbi, NODE_NEW);
+	if (!fi->i_xattr_nid) {
+		/* Allocate new attribute block */
+		struct dnode_of_data dn;
+
+		if (!alloc_nid(sbi, &fi->i_xattr_nid)) {
+			mutex_unlock_op(sbi, NODE_NEW);
+			return -ENOSPC;
+		}
+		set_new_dnode(&dn, inode, NULL, NULL, fi->i_xattr_nid);
+		mark_inode_dirty(inode);
+
+		page = new_node_page(&dn, XATTR_NODE_OFFSET);
+		if (IS_ERR(page)) {
+			alloc_nid_failed(sbi, fi->i_xattr_nid);
+			fi->i_xattr_nid = 0;
+			mutex_unlock_op(sbi, NODE_NEW);
+			return PTR_ERR(page);
+		}
+
+		alloc_nid_done(sbi, fi->i_xattr_nid);
+		base_addr = page_address(page);
+		header = XATTR_HDR(base_addr);
+		header->h_magic = cpu_to_le32(F2FS_XATTR_MAGIC);
+		header->h_refcount = cpu_to_le32(1);
+	} else {
+		/* The inode already has an extended attribute block. */
+		page = get_node_page(sbi, fi->i_xattr_nid);
+		if (IS_ERR(page)) {
+			mutex_unlock_op(sbi, NODE_NEW);
+			return PTR_ERR(page);
+		}
+
+		base_addr = page_address(page);
+		header = XATTR_HDR(base_addr);
+	}
+
+	if (le32_to_cpu(header->h_magic) != F2FS_XATTR_MAGIC) {
+		error = -EIO;
+		goto cleanup;
+	}
+
+	/* find entry with wanted name. */
+	found = 0;
+	list_for_each_xattr(here, base_addr) {
+		if (here->e_name_index != name_index)
+			continue;
+		if (here->e_name_len != name_len)
+			continue;
+		if (!memcmp(here->e_name, name, name_len)) {
+			found = 1;
+			break;
+		}
+	}
+
+	last = here;
+
+	while (!IS_XATTR_LAST_ENTRY(last))
+		last = XATTR_NEXT_ENTRY(last);
+
+	newsize = XATTR_ALIGN(sizeof(struct f2fs_xattr_entry) +
+			name_len + value_len);
+
+	/* 1. Check space */
+	if (value) {
+		/* If value is NULL, it is remove operation.
+		 * In case of update operation, we caculate free.
+		 */
+		free = MIN_OFFSET - ((char *)last - (char *)header);
+		if (found)
+			free = free - ENTRY_SIZE(here);
+
+		if (free < newsize) {
+			error = -ENOSPC;
+			goto cleanup;
+		}
+	}
+
+	/* 2. Remove old entry */
+	if (found) {
+		/* If entry is found, remove old entry.
+		 * If not found, remove operation is not needed.
+		 */
+		struct f2fs_xattr_entry *next = XATTR_NEXT_ENTRY(here);
+		int oldsize = ENTRY_SIZE(here);
+
+		memmove(here, next, (char *)last - (char *)next);
+		last = (struct f2fs_xattr_entry *)((char *)last - oldsize);
+		memset(last, 0, oldsize);
+	}
+
+	/* 3. Write new entry */
+	if (value) {
+		/* Before we come here, old entry is removed.
+		 * We just write new entry. */
+		memset(last, 0, newsize);
+		last->e_name_index = name_index;
+		last->e_name_len = name_len;
+		memcpy(last->e_name, name, name_len);
+		pval = last->e_name + name_len;
+		memcpy(pval, value, value_len);
+		last->e_value_size = cpu_to_le16(value_len);
+	}
+
+	set_page_dirty(page);
+	f2fs_put_page(page, 1);
+
+	if (is_inode_flag_set(fi, FI_ACL_MODE)) {
+		inode->i_mode = fi->i_acl_mode;
+		inode->i_ctime = CURRENT_TIME;
+		clear_inode_flag(fi, FI_ACL_MODE);
+	}
+	f2fs_write_inode(inode, NULL);
+	mutex_unlock_op(sbi, NODE_NEW);
+
+	return 0;
+cleanup:
+	f2fs_put_page(page, 1);
+	mutex_unlock_op(sbi, NODE_NEW);
+	return error;
+}

fs/f2fs/xattr.h

+/**
+ * fs/f2fs/xattr.h
+ *
+ * Copyright (c) 2012 Samsung Electronics Co., Ltd.
+ *             http://www.samsung.com/
+ *
+ * Portions of this code from linux/fs/ext2/xattr.h
+ *
+ * On-disk format of extended attributes for the ext2 filesystem.
+ *
+ * (C) 2001 Andreas Gruenbacher, <a.gruenbacher@computer.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#ifndef __F2FS_XATTR_H__
+#define __F2FS_XATTR_H__
+
+#include <linux/init.h>
+#include <linux/xattr.h>
+
+/* Magic value in attribute blocks */
+#define F2FS_XATTR_MAGIC                0xF2F52011
+
+/* Maximum number of references to one attribute block */
+#define F2FS_XATTR_REFCOUNT_MAX         1024
+
+/* Name indexes */
+#define F2FS_SYSTEM_ADVISE_PREFIX		"system.advise"
+#define F2FS_XATTR_INDEX_USER			1
+#define F2FS_XATTR_INDEX_POSIX_ACL_ACCESS	2
+#define F2FS_XATTR_INDEX_POSIX_ACL_DEFAULT	3
+#define F2FS_XATTR_INDEX_TRUSTED		4
+#define F2FS_XATTR_INDEX_LUSTRE			5
+#define F2FS_XATTR_INDEX_SECURITY		6
+#define F2FS_XATTR_INDEX_ADVISE			7
+
+struct f2fs_xattr_header {
+	__le32  h_magic;        /* magic number for identification */
+	__le32  h_refcount;     /* reference count */
+	__u32   h_reserved[4];  /* zero right now */
+};
+
+struct f2fs_xattr_entry {
+	__u8    e_name_index;
+	__u8    e_name_len;
+	__le16  e_value_size;   /* size of attribute value */
+	char    e_name[0];      /* attribute name */
+};
+
+#define XATTR_HDR(ptr)		((struct f2fs_xattr_header *)(ptr))
+#define XATTR_ENTRY(ptr)	((struct f2fs_xattr_entry *)(ptr))
+#define XATTR_FIRST_ENTRY(ptr)	(XATTR_ENTRY(XATTR_HDR(ptr)+1))
+#define XATTR_ROUND		(3)
+
+#define XATTR_ALIGN(size)	((size + XATTR_ROUND) & ~XATTR_ROUND)
+
+#define ENTRY_SIZE(entry) (XATTR_ALIGN(sizeof(struct f2fs_xattr_entry) + \
+			entry->e_name_len + le16_to_cpu(entry->e_value_size)))
+
+#define XATTR_NEXT_ENTRY(entry)	((struct f2fs_xattr_entry *)((char *)(entry) +\
+			ENTRY_SIZE(entry)))
+
+#define IS_XATTR_LAST_ENTRY(entry) (*(__u32 *)(entry) == 0)
+
+#define list_for_each_xattr(entry, addr) \
+		for (entry = XATTR_FIRST_ENTRY(addr);\
+				!IS_XATTR_LAST_ENTRY(entry);\
+				entry = XATTR_NEXT_ENTRY(entry))
+
+
+#define MIN_OFFSET	XATTR_ALIGN(PAGE_SIZE - \
+			sizeof(struct node_footer) - \
+			sizeof(__u32))
+
+#define MAX_VALUE_LEN	(MIN_OFFSET - sizeof(struct f2fs_xattr_header) - \
+			sizeof(struct f2fs_xattr_entry))
+
+/**
+ * On-disk structure of f2fs_xattr
+ * We use only 1 block for xattr.
+ *
+ * +--------------------+
+ * | f2fs_xattr_header  |
+ * |                    |
+ * +--------------------+
+ * | f2fs_xattr_entry   |
+ * | .e_name_index = 1  |
+ * | .e_name_len = 3    |
+ * | .e_value_size = 14 |
+ * | .e_name = "foo"    |
+ * | "value_of_xattr"   |<- value_offs = e_name + e_name_len
+ * +--------------------+
+ * | f2fs_xattr_entry   |
+ * | .e_name_index = 4  |
+ * | .e_name = "bar"    |
+ * +--------------------+
+ * |                    |
+ * |        Free        |
+ * |                    |
+ * +--------------------+<- MIN_OFFSET
+ * |   node_footer      |
+ * | (nid, ino, offset) |
+ * +--------------------+
+ *
+ **/
+
+#ifdef CONFIG_F2FS_FS_XATTR
+extern const struct xattr_handler f2fs_xattr_user_handler;
+extern const struct xattr_handler f2fs_xattr_trusted_handler;
+extern const struct xattr_handler f2fs_xattr_acl_access_handler;
+extern const struct xattr_handler f2fs_xattr_acl_default_handler;
+extern const struct xattr_handler f2fs_xattr_advise_handler;
+
+extern const struct xattr_handler *f2fs_xattr_handlers[];
+
+extern int f2fs_setxattr(struct inode *inode, int name_index, const char *name,
+		const void *value, size_t value_len);
+extern int f2fs_getxattr(struct inode *inode, int name_index, const char *name,
+		void *buffer, size_t buffer_size);
+extern ssize_t f2fs_listxattr(struct dentry *dentry, char *buffer,
+		size_t buffer_size);
+
+#else
+
+#define f2fs_xattr_handlers	NULL
+static inline int f2fs_setxattr(struct inode *inode, int name_index,
+	const char *name, const void *value, size_t value_len)
+{
+	return -EOPNOTSUPP;
+}
+static inline int f2fs_getxattr(struct inode *inode, int name_index,
+		const char *name, void *buffer, size_t buffer_size)
+{
+	return -EOPNOTSUPP;
+}
+static inline ssize_t f2fs_listxattr(struct dentry *dentry, char *buffer,
+		size_t buffer_size)
+{
+	return -EOPNOTSUPP;
+}
+#endif
+
+#endif /* __F2FS_XATTR_H__ */