/*
 * 2007+ Copyright (c) Evgeniy Polyakov <zbr@ioremap.net>
 * All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#ifndef __NETFS_H
#define __NETFS_H

#include <linux/types.h>
#include <linux/connector.h>
#include <linux/backing-dev.h>

#define POHMELFS_CN_IDX                 5
#define POHMELFS_CN_VAL                 0

#define POHMELFS_CTLINFO_ACK            1
#define POHMELFS_NOINFO_ACK             2

#define POHMELFS_NULL_IDX               65535

/*
 * Network command structure.
 * Will be extended.
 */
struct netfs_cmd {
        __u16                   cmd;    /* Command number */
        __u16                   csize;  /* Attached crypto information size */
        __u16                   cpad;   /* Attached padding size */
        __u16                   ext;    /* External flags */
        __u32                   size;   /* Size of the attached data */
        __u32                   trans;  /* Transaction id */
        __u64                   id;     /* Object ID to operate on. Used for feedback.*/
        __u64                   start;  /* Start of the object. */
        __u64                   iv;     /* IV sequence */
        __u8                    data[0];
};

static inline void netfs_convert_cmd(struct netfs_cmd *cmd)
{
        cmd->id = __be64_to_cpu(cmd->id);
        cmd->start = __be64_to_cpu(cmd->start);
        cmd->iv = __be64_to_cpu(cmd->iv);
        cmd->cmd = __be16_to_cpu(cmd->cmd);
        cmd->ext = __be16_to_cpu(cmd->ext);
        cmd->csize = __be16_to_cpu(cmd->csize);
        cmd->cpad = __be16_to_cpu(cmd->cpad);
        cmd->size = __be32_to_cpu(cmd->size);
}

#define NETFS_TRANS_SINGLE_DST          (1<<0)

enum {
        NETFS_READDIR   = 1,    /* Read directory for given inode number */
        NETFS_READ_PAGE,        /* Read data page from the server */
        NETFS_WRITE_PAGE,       /* Write data page to the server */
        NETFS_CREATE,           /* Create directory entry */
        NETFS_REMOVE,           /* Remove directory entry */

        NETFS_LOOKUP,           /* Lookup single object */
        NETFS_LINK,             /* Create a link */
        NETFS_TRANS,            /* Transaction */
        NETFS_OPEN,             /* Open intent */
        NETFS_INODE_INFO,       /* Metadata cache coherency synchronization message */

        NETFS_PAGE_CACHE,       /* Page cache invalidation message */
        NETFS_READ_PAGES,       /* Read multiple contiguous pages in one go */
        NETFS_RENAME,           /* Rename object */
        NETFS_CAPABILITIES,     /* Capabilities of the client, for example supported crypto */
        NETFS_LOCK,             /* Distributed lock message */

        NETFS_XATTR_SET,        /* Set extended attribute */
        NETFS_XATTR_GET,        /* Get extended attribute */
        NETFS_CMD_MAX
};

enum {
        POHMELFS_FLAGS_ADD = 0, /* Network state control message for ADD */
        POHMELFS_FLAGS_DEL,     /* Network state control message for DEL */
        POHMELFS_FLAGS_SHOW,    /* Network state control message for SHOW */
        POHMELFS_FLAGS_CRYPTO,  /* Crypto data control message */
        POHMELFS_FLAGS_MODIFY,  /* Network state modification message */
        POHMELFS_FLAGS_DUMP,    /* Network state control message for SHOW ALL */
        POHMELFS_FLAGS_FLUSH,   /* Network state control message for FLUSH */
};

/*
 * Always wanted to copy it from socket headers into public one,
 * since they are __KERNEL__ protected there.
 */
#define _K_SS_MAXSIZE   128

struct saddr {
        unsigned short          sa_family;
        char                    addr[_K_SS_MAXSIZE];
};

enum {
        POHMELFS_CRYPTO_HASH = 0,
        POHMELFS_CRYPTO_CIPHER,
};

struct pohmelfs_crypto {
        unsigned int            idx;            /* Config index */
        unsigned short          strlen;         /* Size of the attached crypto string including 0-byte
                                                 * "cbc(aes)" for example */
        unsigned short          type;           /* HMAC, cipher, both */
        unsigned int            keysize;        /* Key size */
        unsigned char           data[0];        /* Algorithm string, key and IV */
};

#define POHMELFS_IO_PERM_READ           (1<<0)
#define POHMELFS_IO_PERM_WRITE          (1<<1)

/*
 * Configuration command used to create table of different remote servers.
 */
struct pohmelfs_ctl {
        __u32                   idx;            /* Config index */
        __u32                   type;           /* Socket type */
        __u32                   proto;          /* Socket protocol */
        __u16                   addrlen;        /* Size of the address */
        __u16                   perm;           /* IO permission */
        __u16                   prio;           /* IO priority */
        struct saddr            addr;           /* Remote server address */
};

/*
 * Ack for userspace about requested command.
 */
struct pohmelfs_cn_ack {
        struct cn_msg           msg;
        int                     error;
        int                     msg_num;
        int                     unused[3];
        struct pohmelfs_ctl     ctl;
};

/*
 * Inode info structure used to sync with server.
 * Check what stat() returns.
 */
struct netfs_inode_info {
        unsigned int            mode;
        unsigned int            nlink;
        unsigned int            uid;
        unsigned int            gid;
        unsigned int            blocksize;
        unsigned int            padding;
        __u64                   ino;
        __u64                   blocks;
        __u64                   rdev;
        __u64                   size;
        __u64                   version;
};

static inline void netfs_convert_inode_info(struct netfs_inode_info *info)
{
        info->mode = __cpu_to_be32(info->mode);
        info->nlink = __cpu_to_be32(info->nlink);
        info->uid = __cpu_to_be32(info->uid);
        info->gid = __cpu_to_be32(info->gid);
        info->blocksize = __cpu_to_be32(info->blocksize);
        info->blocks = __cpu_to_be64(info->blocks);
        info->rdev = __cpu_to_be64(info->rdev);
        info->size = __cpu_to_be64(info->size);
        info->version = __cpu_to_be64(info->version);
        info->ino = __cpu_to_be64(info->ino);
}

/*
 * Cache state machine.
 */
enum {
        NETFS_COMMAND_PENDING = 0,      /* Command is being executed */
        NETFS_INODE_REMOTE_SYNCED,      /* Inode was synced to server */
        NETFS_INODE_REMOTE_DIR_SYNCED,  /* Inode (directory) was synced from the server */
        NETFS_INODE_OWNED,              /* Inode is owned by given host */
        NETFS_INODE_NEED_FLUSH,         /* Inode has to be flushed to the server */
};

/*
 * POHMELFS capabilities: information about supported
 * crypto operations (hash/cipher, modes, key sizes and so on),
 * root informaion (used/available size, number of objects, permissions)
 */
enum pohmelfs_capabilities {
        POHMELFS_CRYPTO_CAPABILITIES = 0,
        POHMELFS_ROOT_CAPABILITIES,
};

/* Read-only mount */
#define POHMELFS_FLAGS_RO               (1<<0)
/* Extended attributes support on/off */
#define POHMELFS_FLAGS_XATTR            (1<<1)

struct netfs_root_capabilities {
        __u64                   nr_files;
        __u64                   used, avail;
        __u64                   flags;
};

static inline void netfs_convert_root_capabilities(struct netfs_root_capabilities *cap)
{
        cap->nr_files = __cpu_to_be64(cap->nr_files);
        cap->used = __cpu_to_be64(cap->used);
        cap->avail = __cpu_to_be64(cap->avail);
        cap->flags = __cpu_to_be64(cap->flags);
}

struct netfs_crypto_capabilities {
        unsigned short          hash_strlen;    /* Hash string length, like "hmac(sha1) including 0 byte "*/
        unsigned short          cipher_strlen;  /* Cipher string length with the same format */
        unsigned int            cipher_keysize; /* Cipher key size */
};

static inline void netfs_convert_crypto_capabilities(struct netfs_crypto_capabilities *cap)
{
        cap->hash_strlen = __cpu_to_be16(cap->hash_strlen);
        cap->cipher_strlen = __cpu_to_be16(cap->cipher_strlen);
        cap->cipher_keysize = __cpu_to_be32(cap->cipher_keysize);
}

enum pohmelfs_lock_type {
        POHMELFS_LOCK_GRAB      = (1<<15),

        POHMELFS_READ_LOCK      = 0,
        POHMELFS_WRITE_LOCK,
};

struct netfs_lock {
        __u64                   start;
        __u64                   ino;
        __u32                   size;
        __u32                   type;
};

static inline void netfs_convert_lock(struct netfs_lock *lock)
{
        lock->start = __cpu_to_be64(lock->start);
        lock->ino = __cpu_to_be64(lock->ino);
        lock->size = __cpu_to_be32(lock->size);
        lock->type = __cpu_to_be32(lock->type);
}

#ifdef __KERNEL__

#include <linux/kernel.h>
#include <linux/completion.h>
#include <linux/rbtree.h>
#include <linux/net.h>
#include <linux/poll.h>

/*
 * Private POHMELFS cache of objects in directory.
 */
struct pohmelfs_name {
        struct rb_node          hash_node;

        struct list_head        sync_create_entry;

        u64                     ino;

        u32                     hash;
        u32                     mode;
        u32                     len;

        char                    *data;
};

/*
 * POHMELFS inode. Main object.
 */
struct pohmelfs_inode {
        struct list_head        inode_entry;            /* Entry in superblock list.
                                                         * Objects which are not bound to dentry require to be dropped
                                                         * in ->put_super()
                                                         */
        struct rb_root          hash_root;              /* The same, but indexed by name hash and len */
        struct mutex            offset_lock;            /* Protect both above trees */

        struct list_head        sync_create_list;       /* List of created but not yet synced to the server children */

        unsigned int            drop_count;

        int                     lock_type;              /* How this inode is locked: read or write */

        int                     error;                  /* Transaction error for given inode */

        long                    state;                  /* State machine above */

        u64                     ino;                    /* Inode number */
        u64                     total_len;              /* Total length of all children names, used to create offsets */

        struct inode            vfs_inode;
};

struct netfs_trans;
typedef int (*netfs_trans_complete_t)(struct page **pages, unsigned int page_num,
                void *private, int err);

struct netfs_state;
struct pohmelfs_sb;

struct netfs_trans {
        /*
         * Transaction header and attached contiguous data live here.
         */
        struct iovec                    iovec;

        /*
         * Pages attached to transaction.
         */
        struct page                     **pages;

        /*
         * List and protecting lock for transaction destination
         * network states.
         */
        spinlock_t                      dst_lock;
        struct list_head                dst_list;

        /*
         * Number of users for given transaction.
         * For example each network state attached to transaction
         * via dst_list increases it.
         */
        atomic_t                        refcnt;

        /*
         * Number of pages attached to given transaction.
         * Some slots in above page array can be NULL, since
         * for example page can be under writeback already,
         * so we skip it in this transaction.
         */
        unsigned int                    page_num;

        /*
         * Transaction flags: single dst or broadcast and so on.
         */
        unsigned int                    flags;

        /*
         * Size of the data, which can be placed into
         * iovec.iov_base area.
         */
        unsigned int                    total_size;

        /*
         * Number of pages to be sent to remote server.
         * Usually equal to above page_num, but in case of partial
         * writeback it can accumulate only pages already completed
         * previous writeback.
         */
        unsigned int                    attached_pages;

        /*
         * Attached number of bytes in all above pages.
         */
        unsigned int                    attached_size;

        /*
         * Unique transacton generation number.
         * Used as identity in the network state tree of transactions.
         */
        unsigned int                    gen;

        /*
         * Transaction completion status.
         */
        int                             result;

        /*
         * Superblock this transaction belongs to
         */
        struct pohmelfs_sb              *psb;

        /*
         * Crypto engine, which processed this transaction.
         * Can be not NULL only if crypto engine holds encrypted pages.
         */
        struct pohmelfs_crypto_engine   *eng;

        /* Private data */
        void                            *private;

        /* Completion callback, invoked just before transaction is destroyed */
        netfs_trans_complete_t          complete;
};

static inline int netfs_trans_cur_len(struct netfs_trans *t)
{
        return (signed)(t->total_size - t->iovec.iov_len);
}

static inline void *netfs_trans_current(struct netfs_trans *t)
{
        return t->iovec.iov_base + t->iovec.iov_len;
}

struct netfs_trans *netfs_trans_alloc(struct pohmelfs_sb *psb, unsigned int size,
                unsigned int flags, unsigned int nr);
void netfs_trans_free(struct netfs_trans *t);
int netfs_trans_finish(struct netfs_trans *t, struct pohmelfs_sb *psb);
int netfs_trans_finish_send(struct netfs_trans *t, struct pohmelfs_sb *psb);

static inline void netfs_trans_reset(struct netfs_trans *t)
{
        t->complete = NULL;
}

struct netfs_trans_dst {
        struct list_head                trans_entry;
        struct rb_node                  state_entry;

        unsigned long                   send_time;

        /*
         * Times this transaction was resent to its old or new,
         * depending on flags, destinations. When it reaches maximum
         * allowed number, specified in superblock->trans_retries,
         * transaction will be freed with ETIMEDOUT error.
         */
        unsigned int                    retries;

        struct netfs_trans              *trans;
        struct netfs_state              *state;
};

struct netfs_trans_dst *netfs_trans_search(struct netfs_state *st, unsigned int gen);
void netfs_trans_drop_dst(struct netfs_trans_dst *dst);
void netfs_trans_drop_dst_nostate(struct netfs_trans_dst *dst);
void netfs_trans_drop_trans(struct netfs_trans *t, struct netfs_state *st);
void netfs_trans_drop_last(struct netfs_trans *t, struct netfs_state *st);
int netfs_trans_resend(struct netfs_trans *t, struct pohmelfs_sb *psb);
int netfs_trans_remove_nolock(struct netfs_trans_dst *dst, struct netfs_state *st);

int netfs_trans_init(void);
void netfs_trans_exit(void);

struct pohmelfs_crypto_engine {
        u64                             iv;             /* Crypto IV for current operation */
        unsigned long                   timeout;        /* Crypto waiting timeout */
        unsigned int                    size;           /* Size of crypto scratchpad */
        void                            *data;          /* Temporal crypto scratchpad */
        /*
         * Crypto operations performed on objects.
         */
        struct crypto_hash              *hash;
        struct crypto_ablkcipher        *cipher;

        struct pohmelfs_crypto_thread   *thread;        /* Crypto thread which hosts this engine */

        struct page                     **pages;
        unsigned int                    page_num;
};

struct pohmelfs_crypto_thread {
        struct list_head                thread_entry;

        struct task_struct              *thread;
        struct pohmelfs_sb              *psb;

        struct pohmelfs_crypto_engine   eng;

        struct netfs_trans              *trans;

        wait_queue_head_t               wait;
        int                             error;

        unsigned int                    size;
        struct page                     *page;
};

void pohmelfs_crypto_thread_make_ready(struct pohmelfs_crypto_thread *th);

/*
 * Network state, attached to one server.
 */
struct netfs_state {
        struct mutex            __state_lock;           /* Can not allow to use the same socket simultaneously */
        struct mutex            __state_send_lock;
        struct netfs_cmd        cmd;                    /* Cached command */
        struct netfs_inode_info info;                   /* Cached inode info */

        void                    *data;                  /* Cached some data */
        unsigned int            size;                   /* Size of that data */

        struct pohmelfs_sb      *psb;                   /* Superblock */

        struct task_struct      *thread;                /* Async receiving thread */

        /* Waiting/polling machinery */
        wait_queue_t            wait;
        wait_queue_head_t       *whead;
        wait_queue_head_t       thread_wait;

        struct mutex            trans_lock;
        struct rb_root          trans_root;

        struct pohmelfs_ctl     ctl;                    /* Remote peer */

        struct socket           *socket;                /* Socket object */
        struct socket           *read_socket;           /* Cached pointer to socket object.
                                                         * Used to determine if between lock drops socket was changed.
                                                         * Never used to read data or any kind of access.
                                                         */
        /*
         * Crypto engines to process incoming data.
         */
        struct pohmelfs_crypto_engine   eng;

        int                     need_reset;
};

int netfs_state_init(struct netfs_state *st);
void netfs_state_exit(struct netfs_state *st);

static inline void netfs_state_lock_send(struct netfs_state *st)
{
        mutex_lock(&st->__state_send_lock);
}

static inline int netfs_state_trylock_send(struct netfs_state *st)
{
        return mutex_trylock(&st->__state_send_lock);
}

static inline void netfs_state_unlock_send(struct netfs_state *st)
{
        BUG_ON(!mutex_is_locked(&st->__state_send_lock));

        mutex_unlock(&st->__state_send_lock);
}

static inline void netfs_state_lock(struct netfs_state *st)
{
        mutex_lock(&st->__state_lock);
}

static inline void netfs_state_unlock(struct netfs_state *st)
{
        BUG_ON(!mutex_is_locked(&st->__state_lock));

        mutex_unlock(&st->__state_lock);
}

static inline unsigned int netfs_state_poll(struct netfs_state *st)
{
        unsigned int revents = POLLHUP | POLLERR;

        netfs_state_lock(st);
        if (st->socket)
                revents = st->socket->ops->poll(NULL, st->socket, NULL);
        netfs_state_unlock(st);

        return revents;
}

struct pohmelfs_config;

struct pohmelfs_sb {
        struct rb_root          mcache_root;
        struct mutex            mcache_lock;
        atomic_long_t           mcache_gen;
        unsigned long           mcache_timeout;

        unsigned int            idx;

        unsigned int            trans_retries;

        atomic_t                trans_gen;

        unsigned int            crypto_attached_size;
        unsigned int            crypto_align_size;

        unsigned int            crypto_fail_unsupported;

        unsigned int            crypto_thread_num;
        struct list_head        crypto_active_list, crypto_ready_list;
        struct mutex            crypto_thread_lock;

        unsigned int            trans_max_pages;
        unsigned long           trans_data_size;
        unsigned long           trans_timeout;

        unsigned long           drop_scan_timeout;
        unsigned long           trans_scan_timeout;

        unsigned long           wait_on_page_timeout;

        struct list_head        flush_list;
        struct list_head        drop_list;
        spinlock_t              ino_lock;
        u64                     ino;

        /*
         * Remote nodes POHMELFS connected to.
         */
        struct list_head        state_list;
        struct mutex            state_lock;

        /*
         * Currently active state to request data from.
         */
        struct pohmelfs_config  *active_state;


        wait_queue_head_t       wait;

        /*
         * Timed checks: stale transactions, inodes to be freed and so on.
         */
        struct delayed_work     dwork;
        struct delayed_work     drop_dwork;

        struct super_block      *sb;

        struct backing_dev_info bdi;

        /*
         * Algorithm strings.
         */
        char                    *hash_string;
        char                    *cipher_string;

        u8                      *hash_key;
        u8                      *cipher_key;

        /*
         * Algorithm string lengths.
         */
        unsigned int            hash_strlen;
        unsigned int            cipher_strlen;
        unsigned int            hash_keysize;
        unsigned int            cipher_keysize;

        /*
         * Controls whether to perfrom crypto processing or not.
         */
        int                     perform_crypto;

        /*
         * POHMELFS statistics.
         */
        u64                     total_size;
        u64                     avail_size;
        atomic_long_t           total_inodes;

        /*
         * Xattr support, read-only and so on.
         */
        u64                     state_flags;

        /*
         * Temporary storage to detect changes in the wait queue.
         */
        long                    flags;
};

static inline void netfs_trans_update(struct netfs_cmd *cmd,
                struct netfs_trans *t, unsigned int size)
{
        unsigned int sz = ALIGN(size, t->psb->crypto_align_size);

        t->iovec.iov_len += sizeof(struct netfs_cmd) + sz;
        cmd->cpad = __cpu_to_be16(sz - size);
}

static inline struct pohmelfs_sb *POHMELFS_SB(struct super_block *sb)
{
        return sb->s_fs_info;
}

static inline struct pohmelfs_inode *POHMELFS_I(struct inode *inode)
{
        return container_of(inode, struct pohmelfs_inode, vfs_inode);
}

static inline u64 pohmelfs_new_ino(struct pohmelfs_sb *psb)
{
        u64 ino;

        spin_lock(&psb->ino_lock);
        ino = psb->ino++;
        spin_unlock(&psb->ino_lock);

        return ino;
}

static inline void pohmelfs_put_inode(struct pohmelfs_inode *pi)
{
        struct pohmelfs_sb *psb = POHMELFS_SB(pi->vfs_inode.i_sb);

        spin_lock(&psb->ino_lock);
        list_move_tail(&pi->inode_entry, &psb->drop_list);
        pi->drop_count++;
        spin_unlock(&psb->ino_lock);
}

struct pohmelfs_config {
        struct list_head        config_entry;

        struct netfs_state      state;
};

struct pohmelfs_config_group {
        /*
         * Entry in the global config group list.
         */
        struct list_head        group_entry;

        /*
         * Index of the current group.
         */
        unsigned int            idx;
        /*
         * Number of config_list entries in this group entry.
         */
        unsigned int            num_entry;
        /*
         * Algorithm strings.
         */
        char                    *hash_string;
        char                    *cipher_string;

        /*
         * Algorithm string lengths.
         */
        unsigned int            hash_strlen;
        unsigned int            cipher_strlen;

        /*
         * Key and its size.
         */
        unsigned int            hash_keysize;
        unsigned int            cipher_keysize;
        u8                      *hash_key;
        u8                      *cipher_key;

        /*
         * List of config entries (network state info) for given idx.
         */
        struct list_head        config_list;
};

int __init pohmelfs_config_init(void);
void pohmelfs_config_exit(void);
int pohmelfs_copy_config(struct pohmelfs_sb *psb);
int pohmelfs_copy_crypto(struct pohmelfs_sb *psb);
int pohmelfs_config_check(struct pohmelfs_config *config, int idx);
int pohmelfs_state_init_one(struct pohmelfs_sb *psb, struct pohmelfs_config *conf);

extern const struct file_operations pohmelfs_dir_fops;
extern const struct inode_operations pohmelfs_dir_inode_ops;

int pohmelfs_state_init(struct pohmelfs_sb *psb);
void pohmelfs_state_exit(struct pohmelfs_sb *psb);
void pohmelfs_state_flush_transactions(struct netfs_state *st);

void pohmelfs_fill_inode(struct inode *inode, struct netfs_inode_info *info);

void pohmelfs_name_del(struct pohmelfs_inode *parent, struct pohmelfs_name *n);
void pohmelfs_free_names(struct pohmelfs_inode *parent);
struct pohmelfs_name *pohmelfs_search_hash(struct pohmelfs_inode *pi, u32 hash);

void pohmelfs_inode_del_inode(struct pohmelfs_sb *psb, struct pohmelfs_inode *pi);

struct pohmelfs_inode *pohmelfs_create_entry_local(struct pohmelfs_sb *psb,
        struct pohmelfs_inode *parent, struct qstr *str, u64 start, int mode);

int pohmelfs_write_create_inode(struct pohmelfs_inode *pi);

int pohmelfs_write_inode_create(struct inode *inode, struct netfs_trans *trans);
int pohmelfs_remove_child(struct pohmelfs_inode *parent, struct pohmelfs_name *n);

struct pohmelfs_inode *pohmelfs_new_inode(struct pohmelfs_sb *psb,
                struct pohmelfs_inode *parent, struct qstr *str,
                struct netfs_inode_info *info, int link);

int pohmelfs_setattr(struct dentry *dentry, struct iattr *attr);
int pohmelfs_setattr_raw(struct inode *inode, struct iattr *attr);

int pohmelfs_meta_command(struct pohmelfs_inode *pi, unsigned int cmd_op, unsigned int flags,
                netfs_trans_complete_t complete, void *priv, u64 start);
int pohmelfs_meta_command_data(struct pohmelfs_inode *pi, u64 id, unsigned int cmd_op, char *addon,
                unsigned int flags, netfs_trans_complete_t complete, void *priv, u64 start);

void pohmelfs_check_states(struct pohmelfs_sb *psb);
void pohmelfs_switch_active(struct pohmelfs_sb *psb);

int pohmelfs_construct_path_string(struct pohmelfs_inode *pi, void *data, int len);
int pohmelfs_path_length(struct pohmelfs_inode *pi);

struct pohmelfs_crypto_completion {
        struct completion       complete;
        int                     error;
};

int pohmelfs_trans_crypt(struct netfs_trans *t, struct pohmelfs_sb *psb);
void pohmelfs_crypto_exit(struct pohmelfs_sb *psb);
int pohmelfs_crypto_init(struct pohmelfs_sb *psb);

int pohmelfs_crypto_engine_init(struct pohmelfs_crypto_engine *e, struct pohmelfs_sb *psb);
void pohmelfs_crypto_engine_exit(struct pohmelfs_crypto_engine *e);

int pohmelfs_crypto_process_input_data(struct pohmelfs_crypto_engine *e, u64 iv,
                void *data, struct page *page, unsigned int size);
int pohmelfs_crypto_process_input_page(struct pohmelfs_crypto_engine *e,
                struct page *page, unsigned int size, u64 iv);

static inline u64 pohmelfs_gen_iv(struct netfs_trans *t)
{
        u64 iv = t->gen;

        iv <<= 32;
        iv |= ((unsigned long)t) & 0xffffffff;

        return iv;
}

int pohmelfs_data_lock(struct pohmelfs_inode *pi, u64 start, u32 size, int type);
int pohmelfs_data_unlock(struct pohmelfs_inode *pi, u64 start, u32 size, int type);
int pohmelfs_data_lock_response(struct netfs_state *st);

static inline int pohmelfs_need_lock(struct pohmelfs_inode *pi, int type)
{
        if (test_bit(NETFS_INODE_OWNED, &pi->state)) {
                if (type == pi->lock_type)
                        return 0;
                if ((type == POHMELFS_READ_LOCK) && (pi->lock_type == POHMELFS_WRITE_LOCK))
                        return 0;
        }

        if (!test_bit(NETFS_INODE_REMOTE_SYNCED, &pi->state))
                return 0;

        return 1;
}

int __init pohmelfs_mcache_init(void);
void pohmelfs_mcache_exit(void);

/* #define CONFIG_POHMELFS_DEBUG */

#ifdef CONFIG_POHMELFS_DEBUG
#define dprintka(f, a...) printk(f, ##a)
#define dprintk(f, a...) printk("%d: " f, task_pid_vnr(current), ##a)
#else
#define dprintka(f, a...) do {} while (0)
#define dprintk(f, a...) do {} while (0)
#endif

static inline void netfs_trans_get(struct netfs_trans *t)
{
        atomic_inc(&t->refcnt);
}

static inline void netfs_trans_put(struct netfs_trans *t)
{
        if (atomic_dec_and_test(&t->refcnt)) {
                dprintk("%s: t: %p, gen: %u, err: %d.\n",
                        __func__, t, t->gen, t->result);
                if (t->complete)
                        t->complete(t->pages, t->page_num,
                                t->private, t->result);
                netfs_trans_free(t);
        }
}

struct pohmelfs_mcache {
        struct rb_node                  mcache_entry;
        struct completion               complete;

        atomic_t                        refcnt;

        u64                             gen;

        void                            *data;
        u64                             start;
        u32                             size;
        int                             err;

        struct netfs_inode_info         info;
};

struct pohmelfs_mcache *pohmelfs_mcache_alloc(struct pohmelfs_sb *psb, u64 start,
                unsigned int size, void *data);
void pohmelfs_mcache_free(struct pohmelfs_sb *psb, struct pohmelfs_mcache *m);
struct pohmelfs_mcache *pohmelfs_mcache_search(struct pohmelfs_sb *psb, u64 gen);
void pohmelfs_mcache_remove_locked(struct pohmelfs_sb *psb, struct pohmelfs_mcache *m);

static inline void pohmelfs_mcache_get(struct pohmelfs_mcache *m)
{
        atomic_inc(&m->refcnt);
}

static inline void pohmelfs_mcache_put(struct pohmelfs_sb *psb,
                struct pohmelfs_mcache *m)
{
        if (atomic_dec_and_test(&m->refcnt))
                pohmelfs_mcache_free(psb, m);
}

/*#define POHMELFS_TRUNCATE_ON_INODE_FLUSH
 */

#endif /* __KERNEL__*/

#endif /* __NETFS_H */