/*
 *   Copyright (C) International Business Machines Corp., 2000-2004
 *   Portions Copyright (C) Christoph Hellwig, 2001-2002
 *
 *   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.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program;  if not, write to the Free Software
 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */

#include <linux/fs.h>
#include <linux/mpage.h>
#include <linux/buffer_head.h>
#include <linux/pagemap.h>
#include <linux/quotaops.h>
#include <linux/writeback.h>
#include <linux/aio.h>
#include "jfs_incore.h"
#include "jfs_inode.h"
#include "jfs_filsys.h"
#include "jfs_imap.h"
#include "jfs_extent.h"
#include "jfs_unicode.h"
#include "jfs_debug.h"


struct inode *jfs_iget(struct super_block *sb, unsigned long ino)
{
        struct inode *inode;
        int ret;

        inode = iget_locked(sb, ino);
        if (!inode)
                return ERR_PTR(-ENOMEM);
        if (!(inode->i_state & I_NEW))
                return inode;

        ret = diRead(inode);
        if (ret < 0) {
                iget_failed(inode);
                return ERR_PTR(ret);
        }

        if (S_ISREG(inode->i_mode)) {
                inode->i_op = &jfs_file_inode_operations;
                inode->i_fop = &jfs_file_operations;
                inode->i_mapping->a_ops = &jfs_aops;
        } else if (S_ISDIR(inode->i_mode)) {
                inode->i_op = &jfs_dir_inode_operations;
                inode->i_fop = &jfs_dir_operations;
        } else if (S_ISLNK(inode->i_mode)) {
                if (inode->i_size >= IDATASIZE) {
                        inode->i_op = &page_symlink_inode_operations;
                        inode->i_mapping->a_ops = &jfs_aops;
                } else {
                        inode->i_op = &jfs_fast_symlink_inode_operations;
                        /*
                         * The inline data should be null-terminated, but
                         * don't let on-disk corruption crash the kernel
                         */
                        JFS_IP(inode)->i_inline[inode->i_size] = '\0';
                }
        } else {
                inode->i_op = &jfs_file_inode_operations;
                init_special_inode(inode, inode->i_mode, inode->i_rdev);
        }
        unlock_new_inode(inode);
        return inode;
}

/*
 * Workhorse of both fsync & write_inode
 */
int jfs_commit_inode(struct inode *inode, int wait)
{
        int rc = 0;
        tid_t tid;
        static int noisy = 5;

        jfs_info("In jfs_commit_inode, inode = 0x%p", inode);

        /*
         * Don't commit if inode has been committed since last being
         * marked dirty, or if it has been deleted.
         */
        if (inode->i_nlink == 0 || !test_cflag(COMMIT_Dirty, inode))
                return 0;

        if (isReadOnly(inode)) {
                /* kernel allows writes to devices on read-only
                 * partitions and may think inode is dirty
                 */
                if (!special_file(inode->i_mode) && noisy) {
                        jfs_err("jfs_commit_inode(0x%p) called on "
                                   "read-only volume", inode);
                        jfs_err("Is remount racy?");
                        noisy--;
                }
                return 0;
        }

        tid = txBegin(inode->i_sb, COMMIT_INODE);
        mutex_lock(&JFS_IP(inode)->commit_mutex);

        /*
         * Retest inode state after taking commit_mutex
         */
        if (inode->i_nlink && test_cflag(COMMIT_Dirty, inode))
                rc = txCommit(tid, 1, &inode, wait ? COMMIT_SYNC : 0);

        txEnd(tid);
        mutex_unlock(&JFS_IP(inode)->commit_mutex);
        return rc;
}

int jfs_write_inode(struct inode *inode, struct writeback_control *wbc)
{
        int wait = wbc->sync_mode == WB_SYNC_ALL;

        if (inode->i_nlink == 0)
                return 0;
        /*
         * If COMMIT_DIRTY is not set, the inode isn't really dirty.
         * It has been committed since the last change, but was still
         * on the dirty inode list.
         */
         if (!test_cflag(COMMIT_Dirty, inode)) {
                /* Make sure committed changes hit the disk */
                jfs_flush_journal(JFS_SBI(inode->i_sb)->log, wait);
                return 0;
         }

        if (jfs_commit_inode(inode, wait)) {
                jfs_err("jfs_write_inode: jfs_commit_inode failed!");
                return -EIO;
        } else
                return 0;
}

void jfs_evict_inode(struct inode *inode)
{
        jfs_info("In jfs_evict_inode, inode = 0x%p", inode);

        if (!inode->i_nlink && !is_bad_inode(inode)) {
                dquot_initialize(inode);

                if (JFS_IP(inode)->fileset == FILESYSTEM_I) {
                        truncate_inode_pages_final(&inode->i_data);

                        if (test_cflag(COMMIT_Freewmap, inode))
                                jfs_free_zero_link(inode);

                        diFree(inode);

                        /*
                         * Free the inode from the quota allocation.
                         */
                        dquot_initialize(inode);
                        dquot_free_inode(inode);
                }
        } else {
                truncate_inode_pages_final(&inode->i_data);
        }
        clear_inode(inode);
        dquot_drop(inode);
}

void jfs_dirty_inode(struct inode *inode, int flags)
{
        static int noisy = 5;

        if (isReadOnly(inode)) {
                if (!special_file(inode->i_mode) && noisy) {
                        /* kernel allows writes to devices on read-only
                         * partitions and may try to mark inode dirty
                         */
                        jfs_err("jfs_dirty_inode called on read-only volume");
                        jfs_err("Is remount racy?");
                        noisy--;
                }
                return;
        }

        set_cflag(COMMIT_Dirty, inode);
}

int jfs_get_block(struct inode *ip, sector_t lblock,
                  struct buffer_head *bh_result, int create)
{
        s64 lblock64 = lblock;
        int rc = 0;
        xad_t xad;
        s64 xaddr;
        int xflag;
        s32 xlen = bh_result->b_size >> ip->i_blkbits;

        /*
         * Take appropriate lock on inode
         */
        if (create)
                IWRITE_LOCK(ip, RDWRLOCK_NORMAL);
        else
                IREAD_LOCK(ip, RDWRLOCK_NORMAL);

        if (((lblock64 << ip->i_sb->s_blocksize_bits) < ip->i_size) &&
            (!xtLookup(ip, lblock64, xlen, &xflag, &xaddr, &xlen, 0)) &&
            xaddr) {
                if (xflag & XAD_NOTRECORDED) {
                        if (!create)
                                /*
                                 * Allocated but not recorded, read treats
                                 * this as a hole
                                 */
                                goto unlock;
#ifdef _JFS_4K
                        XADoffset(&xad, lblock64);
                        XADlength(&xad, xlen);
                        XADaddress(&xad, xaddr);
#else                           /* _JFS_4K */
                        /*
                         * As long as block size = 4K, this isn't a problem.
                         * We should mark the whole page not ABNR, but how
                         * will we know to mark the other blocks BH_New?
                         */
                        BUG();
#endif                          /* _JFS_4K */
                        rc = extRecord(ip, &xad);
                        if (rc)
                                goto unlock;
                        set_buffer_new(bh_result);
                }

                map_bh(bh_result, ip->i_sb, xaddr);
                bh_result->b_size = xlen << ip->i_blkbits;
                goto unlock;
        }
        if (!create)
                goto unlock;

        /*
         * Allocate a new block
         */
#ifdef _JFS_4K
        if ((rc = extHint(ip, lblock64 << ip->i_sb->s_blocksize_bits, &xad)))
                goto unlock;
        rc = extAlloc(ip, xlen, lblock64, &xad, false);
        if (rc)
                goto unlock;

        set_buffer_new(bh_result);
        map_bh(bh_result, ip->i_sb, addressXAD(&xad));
        bh_result->b_size = lengthXAD(&xad) << ip->i_blkbits;

#else                           /* _JFS_4K */
        /*
         * We need to do whatever it takes to keep all but the last buffers
         * in 4K pages - see jfs_write.c
         */
        BUG();
#endif                          /* _JFS_4K */

      unlock:
        /*
         * Release lock on inode
         */
        if (create)
                IWRITE_UNLOCK(ip);
        else
                IREAD_UNLOCK(ip);
        return rc;
}

static int jfs_writepage(struct page *page, struct writeback_control *wbc)
{
        return block_write_full_page(page, jfs_get_block, wbc);
}

static int jfs_writepages(struct address_space *mapping,
                        struct writeback_control *wbc)
{
        return mpage_writepages(mapping, wbc, jfs_get_block);
}

static int jfs_readpage(struct file *file, struct page *page)
{
        return mpage_readpage(page, jfs_get_block);
}

static int jfs_readpages(struct file *file, struct address_space *mapping,
                struct list_head *pages, unsigned nr_pages)
{
        return mpage_readpages(mapping, pages, nr_pages, jfs_get_block);
}

static void jfs_write_failed(struct address_space *mapping, loff_t to)
{
        struct inode *inode = mapping->host;

        if (to > inode->i_size) {
                truncate_pagecache(inode, inode->i_size);
                jfs_truncate(inode);
        }
}

static int jfs_write_begin(struct file *file, struct address_space *mapping,
                                loff_t pos, unsigned len, unsigned flags,
                                struct page **pagep, void **fsdata)
{
        int ret;

        ret = nobh_write_begin(mapping, pos, len, flags, pagep, fsdata,
                                jfs_get_block);
        if (unlikely(ret))
                jfs_write_failed(mapping, pos + len);

        return ret;
}

static sector_t jfs_bmap(struct address_space *mapping, sector_t block)
{
        return generic_block_bmap(mapping, block, jfs_get_block);
}

static ssize_t jfs_direct_IO(int rw, struct kiocb *iocb,
        struct iov_iter *iter, loff_t offset)
{
        struct file *file = iocb->ki_filp;
        struct address_space *mapping = file->f_mapping;
        struct inode *inode = file->f_mapping->host;
        size_t count = iov_iter_count(iter);
        ssize_t ret;

        ret = blockdev_direct_IO(rw, iocb, inode, iter, offset, jfs_get_block);

        /*
         * In case of error extending write may have instantiated a few
         * blocks outside i_size. Trim these off again.
         */
        if (unlikely((rw & WRITE) && ret < 0)) {
                loff_t isize = i_size_read(inode);
                loff_t end = offset + count;

                if (end > isize)
                        jfs_write_failed(mapping, end);
        }

        return ret;
}

const struct address_space_operations jfs_aops = {
        .readpage       = jfs_readpage,
        .readpages      = jfs_readpages,
        .writepage      = jfs_writepage,
        .writepages     = jfs_writepages,
        .write_begin    = jfs_write_begin,
        .write_end      = nobh_write_end,
        .bmap           = jfs_bmap,
        .direct_IO      = jfs_direct_IO,
};

/*
 * Guts of jfs_truncate.  Called with locks already held.  Can be called
 * with directory for truncating directory index table.
 */
void jfs_truncate_nolock(struct inode *ip, loff_t length)
{
        loff_t newsize;
        tid_t tid;

        ASSERT(length >= 0);

        if (test_cflag(COMMIT_Nolink, ip)) {
                xtTruncate(0, ip, length, COMMIT_WMAP);
                return;
        }

        do {
                tid = txBegin(ip->i_sb, 0);

                /*
                 * The commit_mutex cannot be taken before txBegin.
                 * txBegin may block and there is a chance the inode
                 * could be marked dirty and need to be committed
                 * before txBegin unblocks
                 */
                mutex_lock(&JFS_IP(ip)->commit_mutex);

                newsize = xtTruncate(tid, ip, length,
                                     COMMIT_TRUNCATE | COMMIT_PWMAP);
                if (newsize < 0) {
                        txEnd(tid);
                        mutex_unlock(&JFS_IP(ip)->commit_mutex);
                        break;
                }

                ip->i_mtime = ip->i_ctime = CURRENT_TIME;
                mark_inode_dirty(ip);

                txCommit(tid, 1, &ip, 0);
                txEnd(tid);
                mutex_unlock(&JFS_IP(ip)->commit_mutex);
        } while (newsize > length);     /* Truncate isn't always atomic */
}

void jfs_truncate(struct inode *ip)
{
        jfs_info("jfs_truncate: size = 0x%lx", (ulong) ip->i_size);

        nobh_truncate_page(ip->i_mapping, ip->i_size, jfs_get_block);

        IWRITE_LOCK(ip, RDWRLOCK_NORMAL);
        jfs_truncate_nolock(ip, ip->i_size);
        IWRITE_UNLOCK(ip);
}