staging: erofs: add erofs in-memory stuffs

/* SPDX-License-Identifier: GPL-2.0

 *

 * linux/drivers/staging/erofs/internal.h

 *

 * Copyright (C) 2017-2018 HUAWEI, Inc.

 *             http://www.huawei.com/

 * Created by Gao Xiang <gaoxiang25@huawei.com>

 *

 * This file is subject to the terms and conditions of the GNU General Public

 * License.  See the file COPYING in the main directory of the Linux

 * distribution for more details.

 */

#ifndef __INTERNAL_H

#define __INTERNAL_H

#include <linux/fs.h>

#include <linux/dcache.h>

#include <linux/mm.h>

#include <linux/pagemap.h>

#include <linux/bio.h>

#include <linux/buffer_head.h>

#include <linux/cleancache.h>

#include <linux/slab.h>

#include <linux/vmalloc.h>

#include "erofs_fs.h"

/* redefine pr_fmt "erofs: " */

#undef pr_fmt

#define pr_fmt(fmt) "erofs: " fmt

#define errln(x, ...)   pr_err(x "\n", ##__VA_ARGS__)

#define infoln(x, ...)  pr_info(x "\n", ##__VA_ARGS__)

#ifdef CONFIG_EROFS_FS_DEBUG

#define debugln(x, ...) pr_debug(x "\n", ##__VA_ARGS__)

#define dbg_might_sleep         might_sleep

#define DBG_BUGON               BUG_ON

#else

#define debugln(x, ...)         ((void)0)

#define dbg_might_sleep()       ((void)0)

#define DBG_BUGON(...)          ((void)0)

#endif

/* EROFS_SUPER_MAGIC_V1 to represent the whole file system */

#define EROFS_SUPER_MAGIC   EROFS_SUPER_MAGIC_V1

typedef u64 erofs_nid_t;

struct erofs_sb_info {

	u32 blocks;

	u32 meta_blkaddr;

	/* inode slot unit size in bit shift */

	unsigned char islotbits;

	u32 build_time_nsec;

	u64 build_time;

	/* what we really care is nid, rather than ino.. */

	erofs_nid_t root_nid;

	/* used for statfs, f_files - f_favail */

	u64 inos;

	u8 uuid[16];                    /* 128-bit uuid for volume */

	u8 volume_name[16];             /* volume name */

	char *dev_name;

	unsigned int mount_opt;

};

#define EROFS_SB(sb) ((struct erofs_sb_info *)(sb)->s_fs_info)

#define EROFS_I_SB(inode) ((struct erofs_sb_info *)(inode)->i_sb->s_fs_info)

#define clear_opt(sbi, option)	((sbi)->mount_opt &= ~EROFS_MOUNT_##option)

#define set_opt(sbi, option)	((sbi)->mount_opt |= EROFS_MOUNT_##option)

#define test_opt(sbi, option)	((sbi)->mount_opt & EROFS_MOUNT_##option)

/* we strictly follow PAGE_SIZE and no buffer head yet */

#define LOG_BLOCK_SIZE		PAGE_SHIFT

#undef LOG_SECTORS_PER_BLOCK

#define LOG_SECTORS_PER_BLOCK	(PAGE_SHIFT - 9)

#undef SECTORS_PER_BLOCK

#define SECTORS_PER_BLOCK	(1 << SECTORS_PER_BLOCK)

#define EROFS_BLKSIZ		(1 << LOG_BLOCK_SIZE)

#if (EROFS_BLKSIZ % 4096 || !EROFS_BLKSIZ)

#error erofs cannot be used in this platform

#endif

#define ROOT_NID(sb)		((sb)->root_nid)

typedef u64 erofs_off_t;

/* data type for filesystem-wide blocks number */

typedef u32 erofs_blk_t;

#define erofs_blknr(addr)       ((addr) / EROFS_BLKSIZ)

#define erofs_blkoff(addr)      ((addr) % EROFS_BLKSIZ)

#define blknr_to_addr(nr)       ((erofs_off_t)(nr) * EROFS_BLKSIZ)

static inline erofs_off_t iloc(struct erofs_sb_info *sbi, erofs_nid_t nid)

{

	return blknr_to_addr(sbi->meta_blkaddr) + (nid << sbi->islotbits);

}

#define inode_set_inited_xattr(inode)   (EROFS_V(inode)->flags |= 1)

#define inode_has_inited_xattr(inode)   (EROFS_V(inode)->flags & 1)

struct erofs_vnode {

	erofs_nid_t nid;

	unsigned int flags;

	unsigned char data_mapping_mode;

	/* inline size in bytes */

	unsigned char inode_isize;

	unsigned short xattr_isize;

	unsigned xattr_shared_count;

	unsigned *xattr_shared_xattrs;

	erofs_blk_t raw_blkaddr;

	/* the corresponding vfs inode */

	struct inode vfs_inode;

};

#define EROFS_V(ptr)	\

	container_of(ptr, struct erofs_vnode, vfs_inode)

#define __inode_advise(x, bit, bits) \

	(((x) >> (bit)) & ((1 << (bits)) - 1))

#define __inode_version(advise)	\

	__inode_advise(advise, EROFS_I_VERSION_BIT,	\

		EROFS_I_VERSION_BITS)

#define __inode_data_mapping(advise)	\

	__inode_advise(advise, EROFS_I_DATA_MAPPING_BIT,\

		EROFS_I_DATA_MAPPING_BITS)

static inline unsigned long inode_datablocks(struct inode *inode)

{

	/* since i_size cannot be changed */

	return DIV_ROUND_UP(inode->i_size, EROFS_BLKSIZ);

}

static inline bool is_inode_layout_plain(struct inode *inode)

{

	return EROFS_V(inode)->data_mapping_mode == EROFS_INODE_LAYOUT_PLAIN;

}

static inline bool is_inode_layout_compression(struct inode *inode)

{

	return EROFS_V(inode)->data_mapping_mode ==

					EROFS_INODE_LAYOUT_COMPRESSION;

}

static inline bool is_inode_layout_inline(struct inode *inode)

{

	return EROFS_V(inode)->data_mapping_mode == EROFS_INODE_LAYOUT_INLINE;

}

extern const struct super_operations erofs_sops;

extern const struct inode_operations erofs_dir_iops;

extern const struct file_operations erofs_dir_fops;

extern const struct address_space_operations erofs_raw_access_aops;

/*

 * Logical to physical block mapping, used by erofs_map_blocks()

 *

 * Different with other file systems, it is used for 2 access modes:

 *

 * 1) RAW access mode:

 *

 * Users pass a valid (m_lblk, m_lofs -- usually 0) pair,

 * and get the valid m_pblk, m_pofs and the longest m_len(in bytes).

 *

 * Note that m_lblk in the RAW access mode refers to the number of

 * the compressed ondisk block rather than the uncompressed

 * in-memory block for the compressed file.

 *

 * m_pofs equals to m_lofs except for the inline data page.

 *

 * 2) Normal access mode:

 *

 * If the inode is not compressed, it has no difference with

 * the RAW access mode. However, if the inode is compressed,

 * users should pass a valid (m_lblk, m_lofs) pair, and get

 * the needed m_pblk, m_pofs, m_len to get the compressed data

 * and the updated m_lblk, m_lofs which indicates the start

 * of the corresponding uncompressed data in the file.

 */

enum {

	BH_Zipped = BH_PrivateStart,

};

/* Has a disk mapping */

#define EROFS_MAP_MAPPED	(1 << BH_Mapped)

/* Located in metadata (could be copied from bd_inode) */

#define EROFS_MAP_META		(1 << BH_Meta)

/* The extent has been compressed */

#define EROFS_MAP_ZIPPED	(1 << BH_Zipped)

struct erofs_map_blocks {

	erofs_off_t m_pa, m_la;

	u64 m_plen, m_llen;

	unsigned int m_flags;

};

/* Flags used by erofs_map_blocks() */

#define EROFS_GET_BLOCKS_RAW    0x0001

/* data.c */

extern struct page *erofs_get_meta_page(struct super_block *sb,

	erofs_blk_t blkaddr, bool prio);

extern int erofs_map_blocks(struct inode *, struct erofs_map_blocks *, int);

static inline struct page *erofs_get_inline_page(struct inode *inode,

	erofs_blk_t blkaddr)

{

	return erofs_get_meta_page(inode->i_sb,

		blkaddr, S_ISDIR(inode->i_mode));

}

/* inode.c */

extern struct inode *erofs_iget(struct super_block *sb,

	erofs_nid_t nid, bool dir);

/* dir.c */

int erofs_namei(struct inode *dir, struct qstr *name,

	erofs_nid_t *nid, unsigned *d_type);

/* xattr.c */

extern const struct xattr_handler *erofs_xattr_handlers[];

/* symlink */

static inline void set_inode_fast_symlink(struct inode *inode)

{

	inode->i_op = &simple_symlink_inode_operations;

}

static inline bool is_inode_fast_symlink(struct inode *inode)

{

	return inode->i_op == &simple_symlink_inode_operations;

}

static inline void *erofs_vmap(struct page **pages, unsigned int count)

{

#ifdef CONFIG_EROFS_FS_USE_VM_MAP_RAM

	int i = 0;

	while (1) {

		void *addr = vm_map_ram(pages, count, -1, PAGE_KERNEL);

		/* retry two more times (totally 3 times) */

		if (addr != NULL || ++i >= 3)

			return addr;

		vm_unmap_aliases();

	}

	return NULL;

#else

	return vmap(pages, count, VM_MAP, PAGE_KERNEL);

#endif

}

static inline void erofs_vunmap(const void *mem, unsigned int count)

{

#ifdef CONFIG_EROFS_FS_USE_VM_MAP_RAM

	vm_unmap_ram(mem, count);

#else

	vunmap(mem);

#endif

}

#endif