/* SPDX-License-Identifier: GPL-2.0-only */
/*
 * Copyright (C) 2017-2018 HUAWEI, Inc.
 *             https://www.huawei.com/
 * Copyright (C) 2021, Alibaba Cloud
 */
#ifndef __EROFS_INTERNAL_H
#define __EROFS_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/magic.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <linux/iomap.h>
#include "erofs_fs.h"

/* redefine pr_fmt "erofs: " */
#undef pr_fmt
#define pr_fmt(fmt) "erofs: " fmt

__printf(3, 4) void _erofs_err(struct super_block *sb,
                               const char *function, const char *fmt, ...);
#define erofs_err(sb, fmt, ...) \
        _erofs_err(sb, __func__, fmt "\n", ##__VA_ARGS__)
__printf(3, 4) void _erofs_info(struct super_block *sb,
                               const char *function, const char *fmt, ...);
#define erofs_info(sb, fmt, ...) \
        _erofs_info(sb, __func__, fmt "\n", ##__VA_ARGS__)
#ifdef CONFIG_EROFS_FS_DEBUG
#define erofs_dbg(x, ...)       pr_debug(x "\n", ##__VA_ARGS__)
#define DBG_BUGON               BUG_ON
#else
#define erofs_dbg(x, ...)       ((void)0)
#define DBG_BUGON(x)            ((void)(x))
#endif  /* !CONFIG_EROFS_FS_DEBUG */

/* EROFS_SUPER_MAGIC_V1 to represent the whole file system */
#define EROFS_SUPER_MAGIC   EROFS_SUPER_MAGIC_V1

typedef u64 erofs_nid_t;
typedef u64 erofs_off_t;
/* data type for filesystem-wide blocks number */
typedef u32 erofs_blk_t;

struct erofs_device_info {
        char *path;
        struct block_device *bdev;
        struct dax_device *dax_dev;
        u64 dax_part_off;

        u32 blocks;
        u32 mapped_blkaddr;
};

enum {
        EROFS_SYNC_DECOMPRESS_AUTO,
        EROFS_SYNC_DECOMPRESS_FORCE_ON,
        EROFS_SYNC_DECOMPRESS_FORCE_OFF
};

struct erofs_mount_opts {
#ifdef CONFIG_EROFS_FS_ZIP
        /* current strategy of how to use managed cache */
        unsigned char cache_strategy;
        /* strategy of sync decompression (0 - auto, 1 - force on, 2 - force off) */
        unsigned int sync_decompress;

        /* threshold for decompression synchronously */
        unsigned int max_sync_decompress_pages;
#endif
        unsigned int mount_opt;
};

struct erofs_dev_context {
        struct idr tree;
        struct rw_semaphore rwsem;

        unsigned int extra_devices;
};

struct erofs_fs_context {
        struct erofs_mount_opts opt;
        struct erofs_dev_context *devs;
};

/* all filesystem-wide lz4 configurations */
struct erofs_sb_lz4_info {
        /* # of pages needed for EROFS lz4 rolling decompression */
        u16 max_distance_pages;
        /* maximum possible blocks for pclusters in the filesystem */
        u16 max_pclusterblks;
};

struct erofs_sb_info {
        struct erofs_mount_opts opt;    /* options */
#ifdef CONFIG_EROFS_FS_ZIP
        /* list for all registered superblocks, mainly for shrinker */
        struct list_head list;
        struct mutex umount_mutex;

        /* managed XArray arranged in physical block number */
        struct xarray managed_pslots;

        unsigned int shrinker_run_no;
        u16 available_compr_algs;

        /* pseudo inode to manage cached pages */
        struct inode *managed_cache;

        struct erofs_sb_lz4_info lz4;
#endif  /* CONFIG_EROFS_FS_ZIP */
        struct erofs_dev_context *devs;
        struct dax_device *dax_dev;
        u64 dax_part_off;
        u64 total_blocks;
        u32 primarydevice_blocks;

        u32 meta_blkaddr;
#ifdef CONFIG_EROFS_FS_XATTR
        u32 xattr_blkaddr;
#endif
        u16 device_id_mask;     /* valid bits of device id to be used */

        /* inode slot unit size in bit shift */
        unsigned char islotbits;

        u32 sb_size;                    /* total superblock size */
        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 */
        u32 feature_compat;
        u32 feature_incompat;

        /* sysfs support */
        struct kobject s_kobj;          /* /sys/fs/erofs/<devname> */
        struct completion s_kobj_unregister;
};

#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)

/* Mount flags set via mount options or defaults */
#define EROFS_MOUNT_XATTR_USER          0x00000010
#define EROFS_MOUNT_POSIX_ACL           0x00000020
#define EROFS_MOUNT_DAX_ALWAYS          0x00000040
#define EROFS_MOUNT_DAX_NEVER           0x00000080

#define clear_opt(opt, option)  ((opt)->mount_opt &= ~EROFS_MOUNT_##option)
#define set_opt(opt, option)    ((opt)->mount_opt |= EROFS_MOUNT_##option)
#define test_opt(opt, option)   ((opt)->mount_opt & EROFS_MOUNT_##option)

enum {
        EROFS_ZIP_CACHE_DISABLED,
        EROFS_ZIP_CACHE_READAHEAD,
        EROFS_ZIP_CACHE_READAROUND
};

#ifdef CONFIG_EROFS_FS_ZIP
#define EROFS_LOCKED_MAGIC     (INT_MIN | 0xE0F510CCL)

/* basic unit of the workstation of a super_block */
struct erofs_workgroup {
        /* the workgroup index in the workstation */
        pgoff_t index;

        /* overall workgroup reference count */
        atomic_t refcount;
};

#if defined(CONFIG_SMP)
static inline bool erofs_workgroup_try_to_freeze(struct erofs_workgroup *grp,
                                                 int val)
{
        preempt_disable();
        if (val != atomic_cmpxchg(&grp->refcount, val, EROFS_LOCKED_MAGIC)) {
                preempt_enable();
                return false;
        }
        return true;
}

static inline void erofs_workgroup_unfreeze(struct erofs_workgroup *grp,
                                            int orig_val)
{
        /*
         * other observers should notice all modifications
         * in the freezing period.
         */
        smp_mb();
        atomic_set(&grp->refcount, orig_val);
        preempt_enable();
}

static inline int erofs_wait_on_workgroup_freezed(struct erofs_workgroup *grp)
{
        return atomic_cond_read_relaxed(&grp->refcount,
                                        VAL != EROFS_LOCKED_MAGIC);
}
#else
static inline bool erofs_workgroup_try_to_freeze(struct erofs_workgroup *grp,
                                                 int val)
{
        preempt_disable();
        /* no need to spin on UP platforms, let's just disable preemption. */
        if (val != atomic_read(&grp->refcount)) {
                preempt_enable();
                return false;
        }
        return true;
}

static inline void erofs_workgroup_unfreeze(struct erofs_workgroup *grp,
                                            int orig_val)
{
        preempt_enable();
}

static inline int erofs_wait_on_workgroup_freezed(struct erofs_workgroup *grp)
{
        int v = atomic_read(&grp->refcount);

        /* workgroup is never freezed on uniprocessor systems */
        DBG_BUGON(v == EROFS_LOCKED_MAGIC);
        return v;
}
#endif  /* !CONFIG_SMP */
#endif  /* !CONFIG_EROFS_FS_ZIP */

/* 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

enum erofs_kmap_type {
        EROFS_NO_KMAP,          /* don't map the buffer */
        EROFS_KMAP,             /* use kmap() to map the buffer */
        EROFS_KMAP_ATOMIC,      /* use kmap_atomic() to map the buffer */
};

struct erofs_buf {
        struct page *page;
        void *base;
        enum erofs_kmap_type kmap_type;
};
#define __EROFS_BUF_INITIALIZER ((struct erofs_buf){ .page = NULL })

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

#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 EROFS_FEATURE_FUNCS(name, compat, feature) \
static inline bool erofs_sb_has_##name(struct erofs_sb_info *sbi) \
{ \
        return sbi->feature_##compat & EROFS_FEATURE_##feature; \
}

EROFS_FEATURE_FUNCS(zero_padding, incompat, INCOMPAT_ZERO_PADDING)
EROFS_FEATURE_FUNCS(compr_cfgs, incompat, INCOMPAT_COMPR_CFGS)
EROFS_FEATURE_FUNCS(big_pcluster, incompat, INCOMPAT_BIG_PCLUSTER)
EROFS_FEATURE_FUNCS(chunked_file, incompat, INCOMPAT_CHUNKED_FILE)
EROFS_FEATURE_FUNCS(device_table, incompat, INCOMPAT_DEVICE_TABLE)
EROFS_FEATURE_FUNCS(compr_head2, incompat, INCOMPAT_COMPR_HEAD2)
EROFS_FEATURE_FUNCS(ztailpacking, incompat, INCOMPAT_ZTAILPACKING)
EROFS_FEATURE_FUNCS(sb_chksum, compat, COMPAT_SB_CHKSUM)

/* atomic flag definitions */
#define EROFS_I_EA_INITED_BIT   0
#define EROFS_I_Z_INITED_BIT    1

/* bitlock definitions (arranged in reverse order) */
#define EROFS_I_BL_XATTR_BIT    (BITS_PER_LONG - 1)
#define EROFS_I_BL_Z_BIT        (BITS_PER_LONG - 2)

struct erofs_inode {
        erofs_nid_t nid;

        /* atomic flags (including bitlocks) */
        unsigned long flags;

        unsigned char datalayout;
        unsigned char inode_isize;
        unsigned short xattr_isize;

        unsigned int xattr_shared_count;
        unsigned int *xattr_shared_xattrs;

        union {
                erofs_blk_t raw_blkaddr;
                struct {
                        unsigned short  chunkformat;
                        unsigned char   chunkbits;
                };
#ifdef CONFIG_EROFS_FS_ZIP
                struct {
                        unsigned short z_advise;
                        unsigned char  z_algorithmtype[2];
                        unsigned char  z_logical_clusterbits;
                        unsigned long  z_tailextent_headlcn;
                        erofs_off_t    z_idataoff;
                        unsigned short z_idata_size;
                };
#endif  /* CONFIG_EROFS_FS_ZIP */
        };
        /* the corresponding vfs inode */
        struct inode vfs_inode;
};

#define EROFS_I(ptr)    \
        container_of(ptr, struct erofs_inode, vfs_inode)

static inline unsigned long erofs_inode_datablocks(struct inode *inode)
{
        /* since i_size cannot be changed */
        return DIV_ROUND_UP(inode->i_size, EROFS_BLKSIZ);
}

static inline unsigned int erofs_bitrange(unsigned int value, unsigned int bit,
                                          unsigned int bits)
{

        return (value >> bit) & ((1 << bits) - 1);
}


static inline unsigned int erofs_inode_version(unsigned int value)
{
        return erofs_bitrange(value, EROFS_I_VERSION_BIT,
                              EROFS_I_VERSION_BITS);
}

static inline unsigned int erofs_inode_datalayout(unsigned int value)
{
        return erofs_bitrange(value, EROFS_I_DATALAYOUT_BIT,
                              EROFS_I_DATALAYOUT_BITS);
}

/*
 * Different from grab_cache_page_nowait(), reclaiming is never triggered
 * when allocating new pages.
 */
static inline
struct page *erofs_grab_cache_page_nowait(struct address_space *mapping,
                                          pgoff_t index)
{
        return pagecache_get_page(mapping, index,
                        FGP_LOCK|FGP_CREAT|FGP_NOFS|FGP_NOWAIT,
                        readahead_gfp_mask(mapping) & ~__GFP_RECLAIM);
}

extern const struct super_operations erofs_sops;

extern const struct address_space_operations erofs_raw_access_aops;
extern const struct address_space_operations z_erofs_aops;

/*
 * Logical to physical block mapping
 *
 * 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_Encoded = BH_PrivateStart,
        BH_FullMapped,
};

/* 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 is encoded */
#define EROFS_MAP_ENCODED       (1 << BH_Encoded)
/* The length of extent is full */
#define EROFS_MAP_FULL_MAPPED   (1 << BH_FullMapped)

struct erofs_map_blocks {
        struct erofs_buf buf;

        erofs_off_t m_pa, m_la;
        u64 m_plen, m_llen;

        unsigned short m_deviceid;
        char m_algorithmformat;
        unsigned int m_flags;
};

/* Flags used by erofs_map_blocks_flatmode() */
#define EROFS_GET_BLOCKS_RAW    0x0001
/*
 * Used to get the exact decompressed length, e.g. fiemap (consider lookback
 * approach instead if possible since it's more metadata lightweight.)
 */
#define EROFS_GET_BLOCKS_FIEMAP 0x0002
/* Used to map the whole extent if non-negligible data is requested for LZMA */
#define EROFS_GET_BLOCKS_READMORE       0x0004
/* Used to map tail extent for tailpacking inline pcluster */
#define EROFS_GET_BLOCKS_FINDTAIL       0x0008

enum {
        Z_EROFS_COMPRESSION_SHIFTED = Z_EROFS_COMPRESSION_MAX,
        Z_EROFS_COMPRESSION_RUNTIME_MAX
};

/* zmap.c */
extern const struct iomap_ops z_erofs_iomap_report_ops;

#ifdef CONFIG_EROFS_FS_ZIP
int z_erofs_fill_inode(struct inode *inode);
int z_erofs_map_blocks_iter(struct inode *inode,
                            struct erofs_map_blocks *map,
                            int flags);
#else
static inline int z_erofs_fill_inode(struct inode *inode) { return -EOPNOTSUPP; }
static inline int z_erofs_map_blocks_iter(struct inode *inode,
                                          struct erofs_map_blocks *map,
                                          int flags)
{
        return -EOPNOTSUPP;
}
#endif  /* !CONFIG_EROFS_FS_ZIP */

struct erofs_map_dev {
        struct block_device *m_bdev;
        struct dax_device *m_daxdev;
        u64 m_dax_part_off;

        erofs_off_t m_pa;
        unsigned int m_deviceid;
};

/* data.c */
extern const struct file_operations erofs_file_fops;
void erofs_unmap_metabuf(struct erofs_buf *buf);
void erofs_put_metabuf(struct erofs_buf *buf);
void *erofs_bread(struct erofs_buf *buf, struct inode *inode,
                  erofs_blk_t blkaddr, enum erofs_kmap_type type);
void *erofs_read_metabuf(struct erofs_buf *buf, struct super_block *sb,
                         erofs_blk_t blkaddr, enum erofs_kmap_type type);
int erofs_map_dev(struct super_block *sb, struct erofs_map_dev *dev);
int erofs_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
                 u64 start, u64 len);

/* inode.c */
static inline unsigned long erofs_inode_hash(erofs_nid_t nid)
{
#if BITS_PER_LONG == 32
        return (nid >> 32) ^ (nid & 0xffffffff);
#else
        return nid;
#endif
}

extern const struct inode_operations erofs_generic_iops;
extern const struct inode_operations erofs_symlink_iops;
extern const struct inode_operations erofs_fast_symlink_iops;

struct inode *erofs_iget(struct super_block *sb, erofs_nid_t nid, bool dir);
int erofs_getattr(struct user_namespace *mnt_userns, const struct path *path,
                  struct kstat *stat, u32 request_mask,
                  unsigned int query_flags);

/* namei.c */
extern const struct inode_operations erofs_dir_iops;

int erofs_namei(struct inode *dir, struct qstr *name,
                erofs_nid_t *nid, unsigned int *d_type);

/* dir.c */
extern const struct file_operations erofs_dir_fops;

static inline void *erofs_vm_map_ram(struct page **pages, unsigned int count)
{
        int retried = 0;

        while (1) {
                void *p = vm_map_ram(pages, count, -1);

                /* retry two more times (totally 3 times) */
                if (p || ++retried >= 3)
                        return p;
                vm_unmap_aliases();
        }
        return NULL;
}

/* pcpubuf.c */
void *erofs_get_pcpubuf(unsigned int requiredpages);
void erofs_put_pcpubuf(void *ptr);
int erofs_pcpubuf_growsize(unsigned int nrpages);
void erofs_pcpubuf_init(void);
void erofs_pcpubuf_exit(void);

/* sysfs.c */
int erofs_register_sysfs(struct super_block *sb);
void erofs_unregister_sysfs(struct super_block *sb);
int __init erofs_init_sysfs(void);
void erofs_exit_sysfs(void);

/* utils.c / zdata.c */
struct page *erofs_allocpage(struct page **pagepool, gfp_t gfp);
static inline void erofs_pagepool_add(struct page **pagepool,
                struct page *page)
{
        set_page_private(page, (unsigned long)*pagepool);
        *pagepool = page;
}
void erofs_release_pages(struct page **pagepool);

#ifdef CONFIG_EROFS_FS_ZIP
int erofs_workgroup_put(struct erofs_workgroup *grp);
struct erofs_workgroup *erofs_find_workgroup(struct super_block *sb,
                                             pgoff_t index);
struct erofs_workgroup *erofs_insert_workgroup(struct super_block *sb,
                                               struct erofs_workgroup *grp);
void erofs_workgroup_free_rcu(struct erofs_workgroup *grp);
void erofs_shrinker_register(struct super_block *sb);
void erofs_shrinker_unregister(struct super_block *sb);
int __init erofs_init_shrinker(void);
void erofs_exit_shrinker(void);
int __init z_erofs_init_zip_subsystem(void);
void z_erofs_exit_zip_subsystem(void);
int erofs_try_to_free_all_cached_pages(struct erofs_sb_info *sbi,
                                       struct erofs_workgroup *egrp);
int erofs_try_to_free_cached_page(struct page *page);
int z_erofs_load_lz4_config(struct super_block *sb,
                            struct erofs_super_block *dsb,
                            struct z_erofs_lz4_cfgs *lz4, int len);
#else
static inline void erofs_shrinker_register(struct super_block *sb) {}
static inline void erofs_shrinker_unregister(struct super_block *sb) {}
static inline int erofs_init_shrinker(void) { return 0; }
static inline void erofs_exit_shrinker(void) {}
static inline int z_erofs_init_zip_subsystem(void) { return 0; }
static inline void z_erofs_exit_zip_subsystem(void) {}
static inline int z_erofs_load_lz4_config(struct super_block *sb,
                                  struct erofs_super_block *dsb,
                                  struct z_erofs_lz4_cfgs *lz4, int len)
{
        if (lz4 || dsb->u1.lz4_max_distance) {
                erofs_err(sb, "lz4 algorithm isn't enabled");
                return -EINVAL;
        }
        return 0;
}
#endif  /* !CONFIG_EROFS_FS_ZIP */

#ifdef CONFIG_EROFS_FS_ZIP_LZMA
int z_erofs_lzma_init(void);
void z_erofs_lzma_exit(void);
int z_erofs_load_lzma_config(struct super_block *sb,
                             struct erofs_super_block *dsb,
                             struct z_erofs_lzma_cfgs *lzma, int size);
#else
static inline int z_erofs_lzma_init(void) { return 0; }
static inline int z_erofs_lzma_exit(void) { return 0; }
static inline int z_erofs_load_lzma_config(struct super_block *sb,
                             struct erofs_super_block *dsb,
                             struct z_erofs_lzma_cfgs *lzma, int size) {
        if (lzma) {
                erofs_err(sb, "lzma algorithm isn't enabled");
                return -EINVAL;
        }
        return 0;
}
#endif  /* !CONFIG_EROFS_FS_ZIP */

#define EFSCORRUPTED    EUCLEAN         /* Filesystem is corrupted */

#endif  /* __EROFS_INTERNAL_H */