/* -*- mode: c; c-basic-offset: 8; indent-tabs-mode: nil; -*-
 * vim:expandtab:shiftwidth=8:tabstop=8:
 *
 *  lustre/lib/lvfs_linux.c
 *  Lustre filesystem abstraction routines
 *
 *  Copyright (C) 2002, 2003 Cluster File Systems, Inc.
 *   Author: Andreas Dilger <adilger@clusterfs.com>
 *
 *   This file is part of Lustre, http://www.lustre.org.
 *
 *   Lustre is free software; you can redistribute it and/or
 *   modify it under the terms of version 2 of the GNU General Public
 *   License as published by the Free Software Foundation.
 *
 *   Lustre 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.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with Lustre; if not, write to the Free Software
 *   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#ifndef EXPORT_SYMTAB
# define EXPORT_SYMTAB
#endif

#define DEBUG_SUBSYSTEM S_FILTER

#include <linux/version.h>
#include <linux/fs.h>
#include <asm/unistd.h>
#include <linux/slab.h>
#include <linux/pagemap.h>
#include <linux/quotaops.h>
#include <linux/version.h>
#include <libcfs/kp30.h>
#include <linux/lustre_fsfilt.h>
#include <linux/obd.h>
#include <linux/obd_class.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/lustre_compat25.h>
#include <linux/lvfs.h>
#include "lvfs_internal.h"

#include <linux/obd.h>
#include <linux/lustre_lib.h>
#include <linux/lustre_mds.h>   /* for mds_grp_hash_entry */

atomic_t obd_memory;
int obd_memmax;

/* Debugging check only needed during development */
#ifdef OBD_CTXT_DEBUG
# define ASSERT_CTXT_MAGIC(magic) LASSERT((magic) == OBD_RUN_CTXT_MAGIC)
# define ASSERT_NOT_KERNEL_CTXT(msg) LASSERTF(!segment_eq(get_fs(), get_ds()),\
                                              msg)
# define ASSERT_KERNEL_CTXT(msg) LASSERTF(segment_eq(get_fs(), get_ds()), msg)

#else
# define ASSERT_CTXT_MAGIC(magic) do {} while(0)
# define ASSERT_NOT_KERNEL_CTXT(msg) do {} while(0)
# define ASSERT_KERNEL_CTXT(msg) do {} while(0)
#endif

static void push_group_info(struct lvfs_run_ctxt *save,
                            struct group_info *ginfo)
{
        if (!ginfo) {
                save->ngroups = current_ngroups;
                current_ngroups = 0;
        } else {
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,4)
                task_lock(current);
                save->group_info = current->group_info;
                current->group_info = ginfo;
                task_unlock(current);
#else
                LASSERT(ginfo->ngroups <= NGROUPS);
                /* save old */
                save->group_info.ngroups = current->ngroups;
                if (current->ngroups)
                        memcpy(save->group_info.small_block, current->groups,
                               current->ngroups);
                /* push new */
                current->ngroups = ginfo->ngroups;
                if (ginfo->ngroups)
                        memcpy(current->groups, ginfo->small_block,
                               current->ngroups);
#endif
        }
}

static void pop_group_info(struct lvfs_run_ctxt *save,
                           struct group_info *ginfo)
{
        if (!ginfo) {
                current_ngroups = save->ngroups;
        } else {
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,4)
                task_lock(current);
                current->group_info = save->group_info;
                task_unlock(current);
#else
                current->ngroups = ginfo->ngroups;
                if (current->ngroups)
                        memcpy(current->groups, save->group_info.small_block,
                               current->ngroups);
#endif
        }
}

/* push / pop to root of obd store */
void push_ctxt(struct lvfs_run_ctxt *save, struct lvfs_run_ctxt *new_ctx,
               struct lvfs_ucred *uc)
{
        //ASSERT_NOT_KERNEL_CTXT("already in kernel context!\n");
        ASSERT_CTXT_MAGIC(new_ctx->magic);
        LASSERT(save->magic != OBD_RUN_CTXT_MAGIC || save->pid != current->pid);
        OBD_SET_CTXT_MAGIC(save);
        save->pid = current->pid;

        /*
        CDEBUG(D_INFO,
               "= push %p->%p = cur fs %p pwd %p:d%d:i%d (%.*s), pwdmnt %p:%d\n",
               save, current, current->fs, current->fs->pwd,
               atomic_read(&current->fs->pwd->d_count),
               atomic_read(&current->fs->pwd->d_inode->i_count),
               current->fs->pwd->d_name.len, current->fs->pwd->d_name.name,
               current->fs->pwdmnt,
               atomic_read(&current->fs->pwdmnt->mnt_count));
        */

        save->fs = get_fs();
        LASSERT(atomic_read(&current->fs->pwd->d_count));
        LASSERT(atomic_read(&new_ctx->pwd->d_count));
        save->pwd = dget(current->fs->pwd);
        save->pwdmnt = mntget(current->fs->pwdmnt);
        save->ngroups = current_ngroups;
        save->luc.luc_umask = current->fs->umask;

        LASSERT(save->pwd);
        LASSERT(save->pwdmnt);
        LASSERT(new_ctx->pwd);
        LASSERT(new_ctx->pwdmnt);

        if (uc) {
                save->luc.luc_uid = current->uid;
                save->luc.luc_gid = current->gid;
                save->luc.luc_fsuid = current->fsuid;
                save->luc.luc_fsgid = current->fsgid;
                save->luc.luc_cap = current->cap_effective;

                current->uid = uc->luc_uid;
                current->gid = uc->luc_gid;
                current->fsuid = uc->luc_fsuid;
                current->fsgid = uc->luc_fsgid;
                current->cap_effective = uc->luc_cap;

                push_group_info(save, uc->luc_ginfo);
        }
        current->fs->umask = 0; /* umask already applied on client */
        set_fs(new_ctx->fs);
        set_fs_pwd(current->fs, new_ctx->pwdmnt, new_ctx->pwd);

        /*
        CDEBUG(D_INFO,
               "= push %p->%p = cur fs %p pwd %p:d%d:i%d (%.*s), pwdmnt %p:%d\n",
               new_ctx, current, current->fs, current->fs->pwd,
               atomic_read(&current->fs->pwd->d_count),
               atomic_read(&current->fs->pwd->d_inode->i_count),
               current->fs->pwd->d_name.len, current->fs->pwd->d_name.name,
               current->fs->pwdmnt,
               atomic_read(&current->fs->pwdmnt->mnt_count));
        */
}
EXPORT_SYMBOL(push_ctxt);

void pop_ctxt(struct lvfs_run_ctxt *saved, struct lvfs_run_ctxt *new_ctx,
              struct lvfs_ucred *uc)
{
        //printk("pc0");
        ASSERT_CTXT_MAGIC(saved->magic);
        LASSERT(saved->pid == current->pid);
        saved->magic = 0;
        saved->pid = 0;
        //printk("pc1");
        ASSERT_KERNEL_CTXT("popping non-kernel context!\n");

        /*
        CDEBUG(D_INFO,
               " = pop  %p==%p = cur %p pwd %p:d%d:i%d (%.*s), pwdmnt %p:%d\n",
               new_ctx, current, current->fs, current->fs->pwd,
               atomic_read(&current->fs->pwd->d_count),
               atomic_read(&current->fs->pwd->d_inode->i_count),
               current->fs->pwd->d_name.len, current->fs->pwd->d_name.name,
               current->fs->pwdmnt,
               atomic_read(&current->fs->pwdmnt->mnt_count));
        */

        LASSERT(current->fs->pwd == new_ctx->pwd);
        LASSERT(current->fs->pwdmnt == new_ctx->pwdmnt);

        set_fs(saved->fs);
        set_fs_pwd(current->fs, saved->pwdmnt, saved->pwd);

        dput(saved->pwd);
        mntput(saved->pwdmnt);
        current->fs->umask = saved->luc.luc_umask;
        if (uc) {
                current->uid = saved->luc.luc_uid;
                current->gid = saved->luc.luc_gid;
                current->fsuid = saved->luc.luc_fsuid;
                current->fsgid = saved->luc.luc_fsgid;
                current->cap_effective = saved->luc.luc_cap;

                pop_group_info(saved, uc->luc_ginfo);
        }

        /*
        CDEBUG(D_INFO,
               "= pop  %p->%p = cur fs %p pwd %p:d%d:i%d (%.*s), pwdmnt %p:%d\n",
               saved, current, current->fs, current->fs->pwd,
               atomic_read(&current->fs->pwd->d_count),
               atomic_read(&current->fs->pwd->d_inode->i_count),
               current->fs->pwd->d_name.len, current->fs->pwd->d_name.name,
               current->fs->pwdmnt,
               atomic_read(&current->fs->pwdmnt->mnt_count));
        */
}
EXPORT_SYMBOL(pop_ctxt);

/* utility to make a file */
struct dentry *simple_mknod(struct dentry *dir, char *name, int mode, int fix)
{
        struct dentry *dchild;
        int err = 0;
        ENTRY;

        ASSERT_KERNEL_CTXT("kernel doing mknod outside kernel context\n");
        CDEBUG(D_INODE, "creating file %.*s\n", (int)strlen(name), name);

        dchild = ll_lookup_one_len(name, dir, strlen(name));
        if (IS_ERR(dchild))
                GOTO(out_up, dchild);

        if (dchild->d_inode) {
                int old_mode = dchild->d_inode->i_mode;
                if (!S_ISREG(old_mode))
                        GOTO(out_err, err = -EEXIST);

                /* Fixup file permissions if necessary */
                if (fix && (old_mode & S_IALLUGO) != (mode & S_IALLUGO)) {
                        CWARN("fixing permissions on %s from %o to %o\n",
                              name, old_mode, mode);
                        dchild->d_inode->i_mode = (mode & S_IALLUGO) |
                                                  (old_mode & ~S_IALLUGO);
                        mark_inode_dirty(dchild->d_inode);
                }
                GOTO(out_up, dchild);
        }

        err = ll_vfs_create(dir->d_inode, dchild, (mode & ~S_IFMT) | S_IFREG,
                            NULL);
        if (err)
                GOTO(out_err, err);

        RETURN(dchild);

out_err:
        dput(dchild);
        dchild = ERR_PTR(err);
out_up:
        return dchild;
}
EXPORT_SYMBOL(simple_mknod);

/* utility to make a directory */
struct dentry *simple_mkdir(struct dentry *dir, char *name, int mode, int fix)
{
        struct dentry *dchild;
        int err = 0;
        ENTRY;

        ASSERT_KERNEL_CTXT("kernel doing mkdir outside kernel context\n");
        CDEBUG(D_INODE, "creating directory %.*s\n", (int)strlen(name), name);
        dchild = ll_lookup_one_len(name, dir, strlen(name));
        if (IS_ERR(dchild))
                GOTO(out_up, dchild);

        if (dchild->d_inode) {
                int old_mode = dchild->d_inode->i_mode;
                if (!S_ISDIR(old_mode)) {
                        CERROR("found %s (%lu/%u) is mode %o\n", name,
                               dchild->d_inode->i_ino,
                               dchild->d_inode->i_generation, old_mode);
                        GOTO(out_err, err = -ENOTDIR);
                }

                /* Fixup directory permissions if necessary */
                if (fix && (old_mode & S_IALLUGO) != (mode & S_IALLUGO)) {
                        CWARN("fixing permissions on %s from %o to %o\n",
                              name, old_mode, mode);
                        dchild->d_inode->i_mode = (mode & S_IALLUGO) |
                                                  (old_mode & ~S_IALLUGO);
                        mark_inode_dirty(dchild->d_inode);
                }
                GOTO(out_up, dchild);
        }

        err = vfs_mkdir(dir->d_inode, dchild, mode);
        if (err)
                GOTO(out_err, err);

        RETURN(dchild);

out_err:
        dput(dchild);
        dchild = ERR_PTR(err);
out_up:
        return dchild;
}
EXPORT_SYMBOL(simple_mkdir);

/*
 * Read a file from within kernel context.  Prior to calling this
 * function we should already have done a push_ctxt().
 */
int lustre_fread(struct file *file, void *buf, int len, loff_t *off)
{
        ASSERT_KERNEL_CTXT("kernel doing read outside kernel context\n");
        if (!file || !file->f_op || !file->f_op->read || !off)
                RETURN(-ENOSYS);

        return file->f_op->read(file, buf, len, off);
}
EXPORT_SYMBOL(lustre_fread);

/*
 * Write a file from within kernel context.  Prior to calling this
 * function we should already have done a push_ctxt().
 */
int lustre_fwrite(struct file *file, const void *buf, int len, loff_t *off)
{
        ENTRY;
        ASSERT_KERNEL_CTXT("kernel doing write outside kernel context\n");
        if (!file)
                RETURN(-ENOENT);
        if (!file->f_op)
                RETURN(-ENOSYS);
        if (!off)
                RETURN(-EINVAL);

        if (!file->f_op->write)
                RETURN(-EROFS);

        RETURN(file->f_op->write(file, buf, len, off));
}
EXPORT_SYMBOL(lustre_fwrite);

/*
 * Sync a file from within kernel context.  Prior to calling this
 * function we should already have done a push_ctxt().
 */
int lustre_fsync(struct file *file)
{
        ENTRY;
        ASSERT_KERNEL_CTXT("kernel doing sync outside kernel context\n");
        if (!file || !file->f_op || !file->f_op->fsync)
                RETURN(-ENOSYS);

        RETURN(file->f_op->fsync(file, file->f_dentry, 0));
}
EXPORT_SYMBOL(lustre_fsync);

struct l_file *l_dentry_open(struct lvfs_run_ctxt *ctxt, struct l_dentry *de,
                             int flags)
{
        mntget(ctxt->pwdmnt);
        return dentry_open(de, ctxt->pwdmnt, flags);
}
EXPORT_SYMBOL(l_dentry_open);

static int l_filldir(void *__buf, const char *name, int namlen, loff_t offset,
                     ino_t ino, unsigned int d_type)
{
        struct l_linux_dirent *dirent;
        struct l_readdir_callback *buf = (struct l_readdir_callback *)__buf;
        
        dirent = buf->lrc_dirent;
        if (dirent)
               dirent->lld_off = offset; 

        OBD_ALLOC(dirent, sizeof(*dirent));

        list_add_tail(&dirent->lld_list, buf->lrc_list);

        buf->lrc_dirent = dirent;
        dirent->lld_ino = ino;
        LASSERT(sizeof(dirent->lld_name) >= namlen + 1);
        memcpy(dirent->lld_name, name, namlen);

        return 0;
}

long l_readdir(struct file *file, struct list_head *dentry_list)
{
        struct l_linux_dirent *lastdirent;
        struct l_readdir_callback buf;
        int error;

        buf.lrc_dirent = NULL;
        buf.lrc_list = dentry_list; 

        error = vfs_readdir(file, l_filldir, &buf);
        if (error < 0)
                return error;

        lastdirent = buf.lrc_dirent;
        if (lastdirent)
                lastdirent->lld_off = file->f_pos;

        return 0; 
}
EXPORT_SYMBOL(l_readdir);
EXPORT_SYMBOL(obd_memory);
EXPORT_SYMBOL(obd_memmax);

#if defined (CONFIG_DEBUG_MEMORY) && defined(__KERNEL__)
static spinlock_t obd_memlist_lock = SPIN_LOCK_UNLOCKED;
static struct hlist_head *obd_memtable;
static unsigned long obd_memtable_size;

static int lvfs_memdbg_init(int size)
{
        struct hlist_head *head;
        int i;

        LASSERT(size > sizeof(sizeof(struct hlist_head)));
        obd_memtable_size = size / sizeof(struct hlist_head);

        CWARN("allocating %lu malloc entries...\n",
              (unsigned long)obd_memtable_size);

        obd_memtable = kmalloc(size, GFP_KERNEL);
        if (!obd_memtable)
                return -ENOMEM;

        i = obd_memtable_size;
        head = obd_memtable;
        do {
                INIT_HLIST_HEAD(head);
                head++;
                i--;
        } while(i);

        return 0;
}

static int lvfs_memdbg_cleanup(void)
{
        struct hlist_node *node = NULL, *tmp = NULL;
        struct hlist_head *head;
        struct mem_track *mt;
        int i;

        spin_lock(&obd_memlist_lock);
        for (i = 0, head = obd_memtable; i < obd_memtable_size; i++, head++) {
                hlist_for_each_safe(node, tmp, head) {
                        mt = hlist_entry(node, struct mem_track, m_hash);
                        hlist_del_init(&mt->m_hash);
                        kfree(mt);
                }
        }
        spin_unlock(&obd_memlist_lock);
        kfree(obd_memtable);
        return 0;
}

static inline unsigned long const hashfn(void *ptr)
{
        return (unsigned long)ptr &
                (obd_memtable_size - 1);
}

static void __lvfs_memdbg_insert(struct mem_track *mt)
{
        struct hlist_head *head = obd_memtable +
                hashfn(mt->m_ptr);
        hlist_add_head(&mt->m_hash, head);
}

void lvfs_memdbg_insert(struct mem_track *mt)
{
        spin_lock(&obd_memlist_lock);
        __lvfs_memdbg_insert(mt);
        spin_unlock(&obd_memlist_lock);
}
EXPORT_SYMBOL(lvfs_memdbg_insert);

static void __lvfs_memdbg_remove(struct mem_track *mt)
{
        hlist_del_init(&mt->m_hash);
}

void lvfs_memdbg_remove(struct mem_track *mt)
{
        spin_lock(&obd_memlist_lock);
        __lvfs_memdbg_remove(mt);
        spin_unlock(&obd_memlist_lock);
}
EXPORT_SYMBOL(lvfs_memdbg_remove);

static struct mem_track *__lvfs_memdbg_find(void *ptr)
{
        struct hlist_node *node = NULL;
        struct mem_track *mt = NULL;
        struct hlist_head *head;

        head = obd_memtable + hashfn(ptr);

        hlist_for_each(node, head) {
                mt = hlist_entry(node, struct mem_track, m_hash);
                if ((unsigned long)mt->m_ptr == (unsigned long)ptr)
                        break;
                mt = NULL;
        }
        return mt;
}

struct mem_track *lvfs_memdbg_find(void *ptr)
{
        struct mem_track *mt;

        spin_lock(&obd_memlist_lock);
        mt = __lvfs_memdbg_find(ptr);
        spin_unlock(&obd_memlist_lock);
        
        return mt;
}
EXPORT_SYMBOL(lvfs_memdbg_find);

int lvfs_memdbg_check_insert(struct mem_track *mt)
{
        spin_lock(&obd_memlist_lock);
        if (!__lvfs_memdbg_find(mt->m_ptr)) {
                __lvfs_memdbg_insert(mt);
                spin_unlock(&obd_memlist_lock);
                return 1;
        }
        spin_unlock(&obd_memlist_lock);
        return 0;
}
EXPORT_SYMBOL(lvfs_memdbg_check_insert);

struct mem_track *
lvfs_memdbg_check_remove(void *ptr)
{
        struct mem_track *mt;

        spin_lock(&obd_memlist_lock);
        mt = __lvfs_memdbg_find(ptr);
        if (mt) {
                __lvfs_memdbg_remove(mt);
                spin_unlock(&obd_memlist_lock);
                return mt;
        }
        spin_unlock(&obd_memlist_lock);
        return NULL;
}
EXPORT_SYMBOL(lvfs_memdbg_check_remove);
#endif

void lvfs_memdbg_show(void)
{
#if defined (CONFIG_DEBUG_MEMORY) && defined(__KERNEL__)
        struct hlist_node *node = NULL;
        struct hlist_head *head;
        struct mem_track *mt;
#endif
        int leaked;
	
#if defined (CONFIG_DEBUG_MEMORY) && defined(__KERNEL__)
	int i;
#endif

        leaked = atomic_read(&obd_memory);

        if (leaked > 0) {
                CWARN("memory leaks detected (max %d, leaked %d)\n",
                      obd_memmax, leaked);

#if defined (CONFIG_DEBUG_MEMORY) && defined(__KERNEL__)
                spin_lock(&obd_memlist_lock);
                for (i = 0, head = obd_memtable; i < obd_memtable_size; i++, head++) {
                        hlist_for_each(node, head) {
                                mt = hlist_entry(node, struct mem_track, m_hash);
                                CWARN("  ptr: 0x%p, size: %d, src at \"%s\"\n",
                                      mt->m_ptr, mt->m_size, mt->m_loc);
                        }
                }
                spin_unlock(&obd_memlist_lock);
#endif
        }
}
EXPORT_SYMBOL(lvfs_memdbg_show);

static int __init lvfs_linux_init(void)
{
        ENTRY;
#if defined (CONFIG_DEBUG_MEMORY) && defined(__KERNEL__)
        lvfs_memdbg_init(PAGE_SIZE);
#endif
        lvfs_mount_list_init();
        RETURN(0);
}

static void __exit lvfs_linux_exit(void)
{
        ENTRY;

        lvfs_mount_list_cleanup();
        lvfs_memdbg_show();

#if defined (CONFIG_DEBUG_MEMORY) && defined(__KERNEL__)
        lvfs_memdbg_cleanup();
#endif
        EXIT;
        return;
}

MODULE_AUTHOR("Cluster File Systems, Inc. <info@clusterfs.com>");
MODULE_DESCRIPTION("Lustre VFS Filesystem Helper v0.1");
MODULE_LICENSE("GPL");

module_init(lvfs_linux_init);
module_exit(lvfs_linux_exit);