/* SPDX-License-Identifier: GPL-2.0 */
#ifdef pr_fmt
#undef pr_fmt
#endif

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/types.h>
#include <linux/fs.h>
#include <linux/buffer_head.h>
#include "amigaffs.h"
#include <linux/mutex.h>
#include <linux/workqueue.h>

/* Ugly macros make the code more pretty. */

#define AFFS_BLOCK(sb, bh, blk)         (AFFS_HEAD(bh)->table[AFFS_SB(sb)->s_hashsize-1-(blk)])

#define AFFS_HEAD(bh)           ((struct affs_head *)(bh)->b_data)
#define AFFS_TAIL(sb, bh)       ((struct affs_tail *)((bh)->b_data+(sb)->s_blocksize-sizeof(struct affs_tail)))
#define AFFS_ROOT_HEAD(bh)      ((struct affs_root_head *)(bh)->b_data)
#define AFFS_ROOT_TAIL(sb, bh)  ((struct affs_root_tail *)((bh)->b_data+(sb)->s_blocksize-sizeof(struct affs_root_tail)))
#define AFFS_DATA_HEAD(bh)      ((struct affs_data_head *)(bh)->b_data)
#define AFFS_DATA(bh)           (((struct affs_data_head *)(bh)->b_data)->data)

#define AFFS_CACHE_SIZE         PAGE_SIZE

#define AFFS_LC_SIZE            (AFFS_CACHE_SIZE/sizeof(u32)/2)
#define AFFS_AC_SIZE            (AFFS_CACHE_SIZE/sizeof(struct affs_ext_key)/2)
#define AFFS_AC_MASK            (AFFS_AC_SIZE-1)

#define AFFSNAMEMAX 30U

struct affs_ext_key {
        u32     ext;                            /* idx of the extended block */
        u32     key;                            /* block number */
};

/*
 * affs fs inode data in memory
 */
struct affs_inode_info {
        atomic_t i_opencnt;
        struct mutex i_link_lock;               /* Protects internal inode access. */
        struct mutex i_ext_lock;                /* Protects internal inode access. */
#define i_hash_lock i_ext_lock
        u32      i_blkcnt;                      /* block count */
        u32      i_extcnt;                      /* extended block count */
        u32     *i_lc;                          /* linear cache of extended blocks */
        u32      i_lc_size;
        u32      i_lc_shift;
        u32      i_lc_mask;
        struct affs_ext_key *i_ac;              /* associative cache of extended blocks */
        u32      i_ext_last;                    /* last accessed extended block */
        struct buffer_head *i_ext_bh;           /* bh of last extended block */
        loff_t   mmu_private;
        u32      i_protect;                     /* unused attribute bits */
        u32      i_lastalloc;                   /* last allocated block */
        int      i_pa_cnt;                      /* number of preallocated blocks */
        struct inode vfs_inode;
};

/* short cut to get to the affs specific inode data */
static inline struct affs_inode_info *AFFS_I(struct inode *inode)
{
        return container_of(inode, struct affs_inode_info, vfs_inode);
}

/*
 * super-block data in memory
 *
 * Block numbers are adjusted for their actual size
 *
 */

struct affs_bm_info {
        u32 bm_key;                     /* Disk block number */
        u32 bm_free;                    /* Free blocks in here */
};

struct affs_sb_info {
        int s_partition_size;           /* Partition size in blocks. */
        int s_reserved;                 /* Number of reserved blocks. */
        //u32 s_blksize;                        /* Initial device blksize */
        u32 s_data_blksize;             /* size of the data block w/o header */
        u32 s_root_block;               /* FFS root block number. */
        int s_hashsize;                 /* Size of hash table. */
        unsigned long s_flags;          /* See below. */
        kuid_t s_uid;                   /* uid to override */
        kgid_t s_gid;                   /* gid to override */
        umode_t s_mode;                 /* mode to override */
        struct buffer_head *s_root_bh;  /* Cached root block. */
        struct mutex s_bmlock;          /* Protects bitmap access. */
        struct affs_bm_info *s_bitmap;  /* Bitmap infos. */
        u32 s_bmap_count;               /* # of bitmap blocks. */
        u32 s_bmap_bits;                /* # of bits in one bitmap blocks */
        u32 s_last_bmap;
        struct buffer_head *s_bmap_bh;
        char *s_prefix;                 /* Prefix for volumes and assigns. */
        char s_volume[32];              /* Volume prefix for absolute symlinks. */
        spinlock_t symlink_lock;        /* protects the previous two */
        struct super_block *sb;         /* the VFS superblock object */
        int work_queued;                /* non-zero delayed work is queued */
        struct delayed_work sb_work;    /* superblock flush delayed work */
        spinlock_t work_lock;           /* protects sb_work and work_queued */
        struct rcu_head rcu;
};

#define AFFS_MOUNT_SF_INTL              0x0001 /* International filesystem. */
#define AFFS_MOUNT_SF_BM_VALID          0x0002 /* Bitmap is valid. */
#define AFFS_MOUNT_SF_IMMUTABLE         0x0004 /* Protection bits cannot be changed */
#define AFFS_MOUNT_SF_QUIET             0x0008 /* chmod errors will be not reported */
#define AFFS_MOUNT_SF_SETUID            0x0010 /* Ignore Amiga uid */
#define AFFS_MOUNT_SF_SETGID            0x0020 /* Ignore Amiga gid */
#define AFFS_MOUNT_SF_SETMODE           0x0040 /* Ignore Amiga protection bits */
#define AFFS_MOUNT_SF_MUFS              0x0100 /* Use MUFS uid/gid mapping */
#define AFFS_MOUNT_SF_OFS               0x0200 /* Old filesystem */
#define AFFS_MOUNT_SF_PREFIX            0x0400 /* Buffer for prefix is allocated */
#define AFFS_MOUNT_SF_VERBOSE           0x0800 /* Talk about fs when mounting */
#define AFFS_MOUNT_SF_NO_TRUNCATE       0x1000 /* Don't truncate filenames */

#define affs_clear_opt(o, opt)    (o &= ~AFFS_MOUNT_##opt)
#define affs_set_opt(o, opt)      (o |= AFFS_MOUNT_##opt)
#define affs_test_opt(o, opt)     ((o) & AFFS_MOUNT_##opt)

/* short cut to get to the affs specific sb data */
static inline struct affs_sb_info *AFFS_SB(struct super_block *sb)
{
        return sb->s_fs_info;
}

void affs_mark_sb_dirty(struct super_block *sb);

/* amigaffs.c */

extern int      affs_insert_hash(struct inode *inode, struct buffer_head *bh);
extern int      affs_remove_hash(struct inode *dir, struct buffer_head *rem_bh);
extern int      affs_remove_header(struct dentry *dentry);
extern u32      affs_checksum_block(struct super_block *sb, struct buffer_head *bh);
extern void     affs_fix_checksum(struct super_block *sb, struct buffer_head *bh);
extern void     affs_secs_to_datestamp(time64_t secs, struct affs_date *ds);
extern umode_t  affs_prot_to_mode(u32 prot);
extern void     affs_mode_to_prot(struct inode *inode);
__printf(3, 4)
extern void     affs_error(struct super_block *sb, const char *function,
                           const char *fmt, ...);
__printf(3, 4)
extern void     affs_warning(struct super_block *sb, const char *function,
                             const char *fmt, ...);
extern bool     affs_nofilenametruncate(const struct dentry *dentry);
extern int      affs_check_name(const unsigned char *name, int len,
                                bool notruncate);
extern int      affs_copy_name(unsigned char *bstr, struct dentry *dentry);

/* bitmap. c */

extern u32      affs_count_free_blocks(struct super_block *s);
extern void     affs_free_block(struct super_block *sb, u32 block);
extern u32      affs_alloc_block(struct inode *inode, u32 goal);
extern int      affs_init_bitmap(struct super_block *sb, int *flags);
extern void     affs_free_bitmap(struct super_block *sb);

/* namei.c */

extern const struct export_operations affs_export_ops;
extern int      affs_hash_name(struct super_block *sb, const u8 *name, unsigned int len);
extern struct dentry *affs_lookup(struct inode *dir, struct dentry *dentry, unsigned int);
extern int      affs_unlink(struct inode *dir, struct dentry *dentry);
extern int      affs_create(struct mnt_idmap *idmap, struct inode *dir,
                        struct dentry *dentry, umode_t mode, bool);
extern struct dentry *affs_mkdir(struct mnt_idmap *idmap, struct inode *dir,
                        struct dentry *dentry, umode_t mode);
extern int      affs_rmdir(struct inode *dir, struct dentry *dentry);
extern int      affs_link(struct dentry *olddentry, struct inode *dir,
                          struct dentry *dentry);
extern int      affs_symlink(struct mnt_idmap *idmap,
                        struct inode *dir, struct dentry *dentry,
                        const char *symname);
extern int      affs_rename2(struct mnt_idmap *idmap,
                        struct inode *old_dir, struct dentry *old_dentry,
                        struct inode *new_dir, struct dentry *new_dentry,
                        unsigned int flags);

/* inode.c */

extern struct inode             *affs_new_inode(struct inode *dir);
extern int                       affs_notify_change(struct mnt_idmap *idmap,
                                        struct dentry *dentry, struct iattr *attr);
extern void                      affs_evict_inode(struct inode *inode);
extern struct inode             *affs_iget(struct super_block *sb,
                                        unsigned long ino);
extern int                       affs_write_inode(struct inode *inode,
                                        struct writeback_control *wbc);
extern int                       affs_add_entry(struct inode *dir, struct inode *inode,
                                        struct dentry *dentry, s32 type);

/* file.c */

void            affs_free_prealloc(struct inode *inode);
extern void     affs_truncate(struct inode *);
int             affs_file_fsync(struct file *, loff_t, loff_t, int);

/* dir.c */

extern void   affs_dir_truncate(struct inode *);

/* jump tables */

extern const struct inode_operations     affs_file_inode_operations;
extern const struct inode_operations     affs_dir_inode_operations;
extern const struct inode_operations   affs_symlink_inode_operations;
extern const struct file_operations      affs_file_operations;
extern const struct file_operations      affs_file_operations_ofs;
extern const struct file_operations      affs_dir_operations;
extern const struct address_space_operations     affs_symlink_aops;
extern const struct address_space_operations     affs_aops;
extern const struct address_space_operations     affs_aops_ofs;

extern const struct dentry_operations    affs_dentry_operations;
extern const struct dentry_operations    affs_intl_dentry_operations;

static inline bool affs_validblock(struct super_block *sb, int block)
{
        return(block >= AFFS_SB(sb)->s_reserved &&
               block < AFFS_SB(sb)->s_partition_size);
}

static inline void
affs_set_blocksize(struct super_block *sb, int size)
{
        sb_set_blocksize(sb, size);
}
static inline struct buffer_head *
affs_bread(struct super_block *sb, int block)
{
        pr_debug("%s: %d\n", __func__, block);
        if (affs_validblock(sb, block))
                return sb_bread(sb, block);
        return NULL;
}
static inline struct buffer_head *
affs_getblk(struct super_block *sb, int block)
{
        pr_debug("%s: %d\n", __func__, block);
        if (affs_validblock(sb, block))
                return sb_getblk(sb, block);
        return NULL;
}
static inline struct buffer_head *
affs_getzeroblk(struct super_block *sb, int block)
{
        struct buffer_head *bh;
        pr_debug("%s: %d\n", __func__, block);
        if (affs_validblock(sb, block)) {
                bh = sb_getblk(sb, block);
                lock_buffer(bh);
                memset(bh->b_data, 0 , sb->s_blocksize);
                set_buffer_uptodate(bh);
                unlock_buffer(bh);
                return bh;
        }
        return NULL;
}
static inline struct buffer_head *
affs_getemptyblk(struct super_block *sb, int block)
{
        struct buffer_head *bh;
        pr_debug("%s: %d\n", __func__, block);
        if (affs_validblock(sb, block)) {
                bh = sb_getblk(sb, block);
                wait_on_buffer(bh);
                set_buffer_uptodate(bh);
                return bh;
        }
        return NULL;
}
static inline void
affs_brelse(struct buffer_head *bh)
{
        if (bh)
                pr_debug("%s: %lld\n", __func__, (long long) bh->b_blocknr);
        brelse(bh);
}

static inline void
affs_adjust_checksum(struct buffer_head *bh, u32 val)
{
        u32 tmp = be32_to_cpu(((__be32 *)bh->b_data)[5]);
        ((__be32 *)bh->b_data)[5] = cpu_to_be32(tmp - val);
}
static inline void
affs_adjust_bitmapchecksum(struct buffer_head *bh, u32 val)
{
        u32 tmp = be32_to_cpu(((__be32 *)bh->b_data)[0]);
        ((__be32 *)bh->b_data)[0] = cpu_to_be32(tmp - val);
}

static inline void
affs_lock_link(struct inode *inode)
{
        mutex_lock(&AFFS_I(inode)->i_link_lock);
}
static inline void
affs_unlock_link(struct inode *inode)
{
        mutex_unlock(&AFFS_I(inode)->i_link_lock);
}
static inline void
affs_lock_dir(struct inode *inode)
{
        mutex_lock_nested(&AFFS_I(inode)->i_hash_lock, SINGLE_DEPTH_NESTING);
}
static inline void
affs_unlock_dir(struct inode *inode)
{
        mutex_unlock(&AFFS_I(inode)->i_hash_lock);
}
static inline void
affs_lock_ext(struct inode *inode)
{
        mutex_lock(&AFFS_I(inode)->i_ext_lock);
}
static inline void
affs_unlock_ext(struct inode *inode)
{
        mutex_unlock(&AFFS_I(inode)->i_ext_lock);
}