fs/nilfs2/btnode.c - kernel/quantenna - Git at Google

 /*
  * btnode.c - NILFS B-tree node cache
  *
  * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
  *
  * 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.
  *
  * Originally written by Seiji Kihara.
  * Fully revised by Ryusuke Konishi for stabilization and simplification.
  *
  */

 #include <linux/types.h>
 #include <linux/buffer_head.h>
 #include <linux/mm.h>
 #include <linux/backing-dev.h>
 #include <linux/gfp.h>
 #include "nilfs.h"
 #include "mdt.h"
 #include "dat.h"
 #include "page.h"
 #include "btnode.h"

 void nilfs_btnode_cache_clear(struct address_space *btnc)
 {
 	invalidate_mapping_pages(btnc, 0, -1);
 	truncate_inode_pages(btnc, 0);
 }

 struct buffer_head *
 nilfs_btnode_create_block(struct address_space *btnc, __u64 blocknr)
 {
 	struct inode *inode = NILFS_BTNC_I(btnc);
 	struct buffer_head *bh;

 	bh = nilfs_grab_buffer(inode, btnc, blocknr, 1 << BH_NILFS_Node);
 	if (unlikely(!bh))
 		return NULL;

 	if (unlikely(buffer_mapped(bh) || buffer_uptodate(bh) ||
 		     buffer_dirty(bh))) {
 		brelse(bh);
 		BUG();
 	}
 	memset(bh->b_data, 0, 1 << inode->i_blkbits);
 	bh->b_bdev = inode->i_sb->s_bdev;
 	bh->b_blocknr = blocknr;
 	set_buffer_mapped(bh);
 	set_buffer_uptodate(bh);

 	unlock_page(bh->b_page);
 	put_page(bh->b_page);
 	return bh;
 }

 int nilfs_btnode_submit_block(struct address_space *btnc, __u64 blocknr,
 			      sector_t pblocknr, int mode,
 			      struct buffer_head **pbh, sector_t *submit_ptr)
 {
 	struct buffer_head *bh;
 	struct inode *inode = NILFS_BTNC_I(btnc);
 	struct page *page;
 	int err;

 	bh = nilfs_grab_buffer(inode, btnc, blocknr, 1 << BH_NILFS_Node);
 	if (unlikely(!bh))
 		return -ENOMEM;

 	err = -EEXIST; /* internal code */
 	page = bh->b_page;

 	if (buffer_uptodate(bh) || buffer_dirty(bh))
 		goto found;

 	if (pblocknr == 0) {
 		pblocknr = blocknr;
 		if (inode->i_ino != NILFS_DAT_INO) {
 			struct the_nilfs *nilfs = inode->i_sb->s_fs_info;

 			/* blocknr is a virtual block number */
 			err = nilfs_dat_translate(nilfs->ns_dat, blocknr,
 						  &pblocknr);
 			if (unlikely(err)) {
 				brelse(bh);
 				goto out_locked;
 			}
 		}
 	}

 	if (mode == READA) {
 		if (pblocknr != *submit_ptr + 1 || !trylock_buffer(bh)) {
 			err = -EBUSY; /* internal code */
 			brelse(bh);
 			goto out_locked;
 		}
 	} else { /* mode == READ */
 		lock_buffer(bh);
 	}
 	if (buffer_uptodate(bh)) {
 		unlock_buffer(bh);
 		err = -EEXIST; /* internal code */
 		goto found;
 	}
 	set_buffer_mapped(bh);
 	bh->b_bdev = inode->i_sb->s_bdev;
 	bh->b_blocknr = pblocknr; /* set block address for read */
 	bh->b_end_io = end_buffer_read_sync;
 	get_bh(bh);
 	submit_bh(mode, bh);
 	bh->b_blocknr = blocknr; /* set back to the given block address */
 	*submit_ptr = pblocknr;
 	err = 0;
 found:
 	*pbh = bh;

 out_locked:
 	unlock_page(page);
 	put_page(page);
 	return err;
 }

 /**
  * nilfs_btnode_delete - delete B-tree node buffer
  * @bh: buffer to be deleted
  *
  * nilfs_btnode_delete() invalidates the specified buffer and delete the page
  * including the buffer if the page gets unbusy.
  */
 void nilfs_btnode_delete(struct buffer_head *bh)
 {
 	struct address_space *mapping;
 	struct page *page = bh->b_page;
 	pgoff_t index = page_index(page);
 	int still_dirty;

 	get_page(page);
 	lock_page(page);
 	wait_on_page_writeback(page);

 	nilfs_forget_buffer(bh);
 	still_dirty = PageDirty(page);
 	mapping = page->mapping;
 	unlock_page(page);
 	put_page(page);

 	if (!still_dirty && mapping)
 		invalidate_inode_pages2_range(mapping, index, index);
 }

 /**
  * nilfs_btnode_prepare_change_key
  *  prepare to move contents of the block for old key to one of new key.
  *  the old buffer will not be removed, but might be reused for new buffer.
  *  it might return -ENOMEM because of memory allocation errors,
  *  and might return -EIO because of disk read errors.
  */
 int nilfs_btnode_prepare_change_key(struct address_space *btnc,
 				    struct nilfs_btnode_chkey_ctxt *ctxt)
 {
 	struct buffer_head *obh, *nbh;
 	struct inode *inode = NILFS_BTNC_I(btnc);
 	__u64 oldkey = ctxt->oldkey, newkey = ctxt->newkey;
 	int err;

 	if (oldkey == newkey)
 		return 0;

 	obh = ctxt->bh;
 	ctxt->newbh = NULL;

 	if (inode->i_blkbits == PAGE_SHIFT) {
 		lock_page(obh->b_page);
 		/*
 		 * We cannot call radix_tree_preload for the kernels older
 		 * than 2.6.23, because it is not exported for modules.
 		 */
 retry:
 		err = radix_tree_preload(GFP_NOFS & ~__GFP_HIGHMEM);
 		if (err)
 			goto failed_unlock;
 		/* BUG_ON(oldkey != obh->b_page->index); */
 		if (unlikely(oldkey != obh->b_page->index))
 			NILFS_PAGE_BUG(obh->b_page,
 				       "invalid oldkey %lld (newkey=%lld)",
 				       (unsigned long long)oldkey,
 				       (unsigned long long)newkey);

 		spin_lock_irq(&btnc->tree_lock);
 		err = radix_tree_insert(&btnc->page_tree, newkey, obh->b_page);
 		spin_unlock_irq(&btnc->tree_lock);
 		/*
 		 * Note: page->index will not change to newkey until
 		 * nilfs_btnode_commit_change_key() will be called.
 		 * To protect the page in intermediate state, the page lock
 		 * is held.
 		 */
 		radix_tree_preload_end();
 		if (!err)
 			return 0;
 		else if (err != -EEXIST)
 			goto failed_unlock;

 		err = invalidate_inode_pages2_range(btnc, newkey, newkey);
 		if (!err)
 			goto retry;
 		/* fallback to copy mode */
 		unlock_page(obh->b_page);
 	}

 	nbh = nilfs_btnode_create_block(btnc, newkey);
 	if (!nbh)
 		return -ENOMEM;

 	BUG_ON(nbh == obh);
 	ctxt->newbh = nbh;
 	return 0;

  failed_unlock:
 	unlock_page(obh->b_page);
 	return err;
 }

 /**
  * nilfs_btnode_commit_change_key
  *  commit the change_key operation prepared by prepare_change_key().
  */
 void nilfs_btnode_commit_change_key(struct address_space *btnc,
 				    struct nilfs_btnode_chkey_ctxt *ctxt)
 {
 	struct buffer_head *obh = ctxt->bh, *nbh = ctxt->newbh;
 	__u64 oldkey = ctxt->oldkey, newkey = ctxt->newkey;
 	struct page *opage;

 	if (oldkey == newkey)
 		return;

 	if (nbh == NULL) {	/* blocksize == pagesize */
 		opage = obh->b_page;
 		if (unlikely(oldkey != opage->index))
 			NILFS_PAGE_BUG(opage,
 				       "invalid oldkey %lld (newkey=%lld)",
 				       (unsigned long long)oldkey,
 				       (unsigned long long)newkey);
 		mark_buffer_dirty(obh);

 		spin_lock_irq(&btnc->tree_lock);
 		radix_tree_delete(&btnc->page_tree, oldkey);
 		radix_tree_tag_set(&btnc->page_tree, newkey,
 				   PAGECACHE_TAG_DIRTY);
 		spin_unlock_irq(&btnc->tree_lock);

 		opage->index = obh->b_blocknr = newkey;
 		unlock_page(opage);
 	} else {
 		nilfs_copy_buffer(nbh, obh);
 		mark_buffer_dirty(nbh);

 		nbh->b_blocknr = newkey;
 		ctxt->bh = nbh;
 		nilfs_btnode_delete(obh); /* will decrement bh->b_count */
 	}
 }

 /**
  * nilfs_btnode_abort_change_key
  *  abort the change_key operation prepared by prepare_change_key().
  */
 void nilfs_btnode_abort_change_key(struct address_space *btnc,
 				   struct nilfs_btnode_chkey_ctxt *ctxt)
 {
 	struct buffer_head *nbh = ctxt->newbh;
 	__u64 oldkey = ctxt->oldkey, newkey = ctxt->newkey;

 	if (oldkey == newkey)
 		return;

 	if (nbh == NULL) {	/* blocksize == pagesize */
 		spin_lock_irq(&btnc->tree_lock);
 		radix_tree_delete(&btnc->page_tree, newkey);
 		spin_unlock_irq(&btnc->tree_lock);
 		unlock_page(ctxt->bh->b_page);
 	} else
 		brelse(nbh);
 }
	/*
	* btnode.c - NILFS B-tree node cache
	*
	* Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
	*
	* 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.
	*
	* Originally written by Seiji Kihara.
	* Fully revised by Ryusuke Konishi for stabilization and simplification.
	*
	*/

	#include <linux/types.h>
	#include <linux/buffer_head.h>
	#include <linux/mm.h>
	#include <linux/backing-dev.h>
	#include <linux/gfp.h>
	#include "nilfs.h"
	#include "mdt.h"
	#include "dat.h"
	#include "page.h"
	#include "btnode.h"

	void nilfs_btnode_cache_clear(struct address_space *btnc)
	{
	invalidate_mapping_pages(btnc, 0, -1);
	truncate_inode_pages(btnc, 0);
	}

	struct buffer_head *
	nilfs_btnode_create_block(struct address_space *btnc, __u64 blocknr)
	{
	struct inode *inode = NILFS_BTNC_I(btnc);
	struct buffer_head *bh;

	bh = nilfs_grab_buffer(inode, btnc, blocknr, 1 << BH_NILFS_Node);
	if (unlikely(!bh))
	return NULL;

	if (unlikely(buffer_mapped(bh) \|\| buffer_uptodate(bh) \|\|
	buffer_dirty(bh))) {
	brelse(bh);
	BUG();
	}
	memset(bh->b_data, 0, 1 << inode->i_blkbits);
	bh->b_bdev = inode->i_sb->s_bdev;
	bh->b_blocknr = blocknr;
	set_buffer_mapped(bh);
	set_buffer_uptodate(bh);

	unlock_page(bh->b_page);
	put_page(bh->b_page);
	return bh;
	}

	int nilfs_btnode_submit_block(struct address_space *btnc, __u64 blocknr,
	sector_t pblocknr, int mode,
	struct buffer_head *pbh, sector_t submit_ptr)
	{
	struct buffer_head *bh;
	struct inode *inode = NILFS_BTNC_I(btnc);
	struct page *page;
	int err;

	bh = nilfs_grab_buffer(inode, btnc, blocknr, 1 << BH_NILFS_Node);
	if (unlikely(!bh))
	return -ENOMEM;

	err = -EEXIST; /* internal code */
	page = bh->b_page;

	if (buffer_uptodate(bh) \|\| buffer_dirty(bh))
	goto found;

	if (pblocknr == 0) {
	pblocknr = blocknr;
	if (inode->i_ino != NILFS_DAT_INO) {
	struct the_nilfs *nilfs = inode->i_sb->s_fs_info;

	/* blocknr is a virtual block number */
	err = nilfs_dat_translate(nilfs->ns_dat, blocknr,
	&pblocknr);
	if (unlikely(err)) {
	brelse(bh);
	goto out_locked;
	}
	}
	}

	if (mode == READA) {
	if (pblocknr != *submit_ptr + 1 \|\| !trylock_buffer(bh)) {
	err = -EBUSY; /* internal code */
	brelse(bh);
	goto out_locked;
	}
	} else { /* mode == READ */
	lock_buffer(bh);
	}
	if (buffer_uptodate(bh)) {
	unlock_buffer(bh);
	err = -EEXIST; /* internal code */
	goto found;
	}
	set_buffer_mapped(bh);
	bh->b_bdev = inode->i_sb->s_bdev;
	bh->b_blocknr = pblocknr; /* set block address for read */
	bh->b_end_io = end_buffer_read_sync;
	get_bh(bh);
	submit_bh(mode, bh);
	bh->b_blocknr = blocknr; /* set back to the given block address */
	*submit_ptr = pblocknr;
	err = 0;
	found:
	*pbh = bh;

	out_locked:
	unlock_page(page);
	put_page(page);
	return err;
	}

	/**
	* nilfs_btnode_delete - delete B-tree node buffer
	* @bh: buffer to be deleted
	*
	* nilfs_btnode_delete() invalidates the specified buffer and delete the page
	* including the buffer if the page gets unbusy.
	*/
	void nilfs_btnode_delete(struct buffer_head *bh)
	{
	struct address_space *mapping;
	struct page *page = bh->b_page;
	pgoff_t index = page_index(page);
	int still_dirty;

	get_page(page);
	lock_page(page);
	wait_on_page_writeback(page);

	nilfs_forget_buffer(bh);
	still_dirty = PageDirty(page);
	mapping = page->mapping;
	unlock_page(page);
	put_page(page);

	if (!still_dirty && mapping)
	invalidate_inode_pages2_range(mapping, index, index);
	}

	/**
	* nilfs_btnode_prepare_change_key
	* prepare to move contents of the block for old key to one of new key.
	* the old buffer will not be removed, but might be reused for new buffer.
	* it might return -ENOMEM because of memory allocation errors,
	* and might return -EIO because of disk read errors.
	*/
	int nilfs_btnode_prepare_change_key(struct address_space *btnc,
	struct nilfs_btnode_chkey_ctxt *ctxt)
	{
	struct buffer_head obh, nbh;
	struct inode *inode = NILFS_BTNC_I(btnc);
	__u64 oldkey = ctxt->oldkey, newkey = ctxt->newkey;
	int err;

	if (oldkey == newkey)
	return 0;

	obh = ctxt->bh;
	ctxt->newbh = NULL;

	if (inode->i_blkbits == PAGE_SHIFT) {
	lock_page(obh->b_page);
	/*
	* We cannot call radix_tree_preload for the kernels older
	* than 2.6.23, because it is not exported for modules.
	*/
	retry:
	err = radix_tree_preload(GFP_NOFS & ~__GFP_HIGHMEM);
	if (err)
	goto failed_unlock;
	/* BUG_ON(oldkey != obh->b_page->index); */
	if (unlikely(oldkey != obh->b_page->index))
	NILFS_PAGE_BUG(obh->b_page,
	"invalid oldkey %lld (newkey=%lld)",
	(unsigned long long)oldkey,
	(unsigned long long)newkey);

	spin_lock_irq(&btnc->tree_lock);
	err = radix_tree_insert(&btnc->page_tree, newkey, obh->b_page);
	spin_unlock_irq(&btnc->tree_lock);
	/*
	* Note: page->index will not change to newkey until
	* nilfs_btnode_commit_change_key() will be called.
	* To protect the page in intermediate state, the page lock
	* is held.
	*/
	radix_tree_preload_end();
	if (!err)
	return 0;
	else if (err != -EEXIST)
	goto failed_unlock;

	err = invalidate_inode_pages2_range(btnc, newkey, newkey);
	if (!err)
	goto retry;
	/* fallback to copy mode */
	unlock_page(obh->b_page);
	}

	nbh = nilfs_btnode_create_block(btnc, newkey);
	if (!nbh)
	return -ENOMEM;

	BUG_ON(nbh == obh);
	ctxt->newbh = nbh;
	return 0;

	failed_unlock:
	unlock_page(obh->b_page);
	return err;
	}

	/**
	* nilfs_btnode_commit_change_key
	* commit the change_key operation prepared by prepare_change_key().
	*/
	void nilfs_btnode_commit_change_key(struct address_space *btnc,
	struct nilfs_btnode_chkey_ctxt *ctxt)
	{
	struct buffer_head obh = ctxt->bh, nbh = ctxt->newbh;
	__u64 oldkey = ctxt->oldkey, newkey = ctxt->newkey;
	struct page *opage;

	if (oldkey == newkey)
	return;

	if (nbh == NULL) { /* blocksize == pagesize */
	opage = obh->b_page;
	if (unlikely(oldkey != opage->index))
	NILFS_PAGE_BUG(opage,
	"invalid oldkey %lld (newkey=%lld)",
	(unsigned long long)oldkey,
	(unsigned long long)newkey);
	mark_buffer_dirty(obh);

	spin_lock_irq(&btnc->tree_lock);
	radix_tree_delete(&btnc->page_tree, oldkey);
	radix_tree_tag_set(&btnc->page_tree, newkey,
	PAGECACHE_TAG_DIRTY);
	spin_unlock_irq(&btnc->tree_lock);

	opage->index = obh->b_blocknr = newkey;
	unlock_page(opage);
	} else {
	nilfs_copy_buffer(nbh, obh);
	mark_buffer_dirty(nbh);

	nbh->b_blocknr = newkey;
	ctxt->bh = nbh;
	nilfs_btnode_delete(obh); /* will decrement bh->b_count */
	}
	}

	/**
	* nilfs_btnode_abort_change_key
	* abort the change_key operation prepared by prepare_change_key().
	*/
	void nilfs_btnode_abort_change_key(struct address_space *btnc,
	struct nilfs_btnode_chkey_ctxt *ctxt)
	{
	struct buffer_head *nbh = ctxt->newbh;
	__u64 oldkey = ctxt->oldkey, newkey = ctxt->newkey;

	if (oldkey == newkey)
	return;

	if (nbh == NULL) { /* blocksize == pagesize */
	spin_lock_irq(&btnc->tree_lock);
	radix_tree_delete(&btnc->page_tree, newkey);
	spin_unlock_irq(&btnc->tree_lock);
	unlock_page(ctxt->bh->b_page);
	} else
	brelse(nbh);
	}