/*
   *   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 "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 (test_cflag(COMMIT_Nolink, inode))
  		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(&inode->i_data, 0);

  			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(&inode->i_data, 0);

  	}

  	end_writeback(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 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)) {
  		loff_t isize = mapping->host->i_size;
  		if (pos + len > isize)
  			vmtruncate(mapping->host, isize);
  	}
  
  	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,
  	const struct iovec *iov, loff_t offset, unsigned long nr_segs)
  {
  	struct file *file = iocb->ki_filp;
  	struct inode *inode = file->f_mapping->host;

  	ssize_t ret;

  	ret = blockdev_direct_IO(rw, iocb, inode, iov, offset, nr_segs,
  				 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 + iov_length(iov, nr_segs);
  
  		if (end > isize)
  			vmtruncate(inode, isize);
  	}
  
  	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);
  }