[deliverable/linux.git] / fs / nilfs2 / btnode.c

/*
 * 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.
 *
 * 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., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 *
 * This file was originally written by Seiji Kihara <kihara@osrg.net>
 * and fully revised by Ryusuke Konishi <ryusuke@osrg.net> 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_init(struct address_space *btnc,
			     struct backing_dev_info *bdi)
{
	nilfs_mapping_init(btnc, bdi);
}

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 = NILFS_I_NILFS(inode)->ns_bdev;
	bh->b_blocknr = blocknr;
	set_buffer_mapped(bh);
	set_buffer_uptodate(bh);

	unlock_page(bh->b_page);
	page_cache_release(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 inode *dat = NILFS_I_NILFS(inode)->ns_dat;

			/* blocknr is a virtual block number */
			err = nilfs_dat_translate(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 = NILFS_I_NILFS(inode)->ns_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);
	page_cache_release(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;

	page_cache_get(page);
	lock_page(page);
	wait_on_page_writeback(page);

	nilfs_forget_buffer(bh);
	still_dirty = PageDirty(page);
	mapping = page->mapping;
	unlock_page(page);
	page_cache_release(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_CACHE_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);
		nilfs_btnode_mark_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);
		nilfs_btnode_mark_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);
}
Commit	Line	Data
a60be987 RK	1	/*
	2	* btnode.c - NILFS B-tree node cache
	3	*
	4	* Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
	5	*
	6	* This program is free software; you can redistribute it and/or modify
	7	* it under the terms of the GNU General Public License as published by
	8	* the Free Software Foundation; either version 2 of the License, or
	9	* (at your option) any later version.
	10	*
	11	* This program is distributed in the hope that it will be useful,
	12	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	13	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	14	* GNU General Public License for more details.
	15	*
	16	* You should have received a copy of the GNU General Public License
	17	* along with this program; if not, write to the Free Software
	18	* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
	19	*
	20	* This file was originally written by Seiji Kihara <kihara@osrg.net>
	21	* and fully revised by Ryusuke Konishi <ryusuke@osrg.net> for
	22	* stabilization and simplification.
	23	*
	24	*/
	25
	26	#include <linux/types.h>
	27	#include <linux/buffer_head.h>
	28	#include <linux/mm.h>
	29	#include <linux/backing-dev.h>
5a0e3ad6	30	#include <linux/gfp.h>
a60be987 RK	31	#include "nilfs.h"
	32	#include "mdt.h"
	33	#include "dat.h"
	34	#include "page.h"
	35	#include "btnode.h"
	36
a53b4751 RK	37	void nilfs_btnode_cache_init(struct address_space *btnc,
a53b4751 RK	38	struct backing_dev_info *bdi)
a60be987	39	{
7eaceacc	40	nilfs_mapping_init(btnc, bdi);
a60be987 RK	41	}
	42
	43	void nilfs_btnode_cache_clear(struct address_space *btnc)
	44	{
	45	invalidate_mapping_pages(btnc, 0, -1);
	46	truncate_inode_pages(btnc, 0);
	47	}
	48
d501d736 RK	49	struct buffer_head *
	50	nilfs_btnode_create_block(struct address_space *btnc, __u64 blocknr)
	51	{
	52	struct inode *inode = NILFS_BTNC_I(btnc);
	53	struct buffer_head *bh;
	54
	55	bh = nilfs_grab_buffer(inode, btnc, blocknr, 1 << BH_NILFS_Node);
	56	if (unlikely(!bh))
	57	return NULL;
	58
	59	if (unlikely(buffer_mapped(bh) \|\| buffer_uptodate(bh) \|\|
	60	buffer_dirty(bh))) {
	61	brelse(bh);
	62	BUG();
	63	}
	64	memset(bh->b_data, 0, 1 << inode->i_blkbits);
	65	bh->b_bdev = NILFS_I_NILFS(inode)->ns_bdev;
	66	bh->b_blocknr = blocknr;
	67	set_buffer_mapped(bh);
	68	set_buffer_uptodate(bh);
	69
	70	unlock_page(bh->b_page);
	71	page_cache_release(bh->b_page);
	72	return bh;
	73	}
	74
a60be987	75	int nilfs_btnode_submit_block(struct address_space *btnc, __u64 blocknr,
26dfdd8e RK	76	sector_t pblocknr, int mode,
26dfdd8e RK	77	struct buffer_head *pbh, sector_t submit_ptr)
a60be987 RK	78	{
	79	struct buffer_head *bh;
	80	struct inode *inode = NILFS_BTNC_I(btnc);
f8e6cc01	81	struct page *page;
a60be987 RK	82	int err;
	83
	84	bh = nilfs_grab_buffer(inode, btnc, blocknr, 1 << BH_NILFS_Node);
	85	if (unlikely(!bh))
	86	return -ENOMEM;
	87
	88	err = -EEXIST; /* internal code */
f8e6cc01	89	page = bh->b_page;
a60be987 RK	90
	91	if (buffer_uptodate(bh) \|\| buffer_dirty(bh))
	92	goto found;
	93
	94	if (pblocknr == 0) {
	95	pblocknr = blocknr;
	96	if (inode->i_ino != NILFS_DAT_INO) {
365e215c	97	struct inode *dat = NILFS_I_NILFS(inode)->ns_dat;
a60be987 RK	98
	99	/* blocknr is a virtual block number */
	100	err = nilfs_dat_translate(dat, blocknr, &pblocknr);
	101	if (unlikely(err)) {
	102	brelse(bh);
	103	goto out_locked;
	104	}
	105	}
	106	}
26dfdd8e RK	107
	108	if (mode == READA) {
	109	if (pblocknr != *submit_ptr + 1 \|\| !trylock_buffer(bh)) {
	110	err = -EBUSY; /* internal code */
	111	brelse(bh);
	112	goto out_locked;
	113	}
	114	} else { /* mode == READ */
	115	lock_buffer(bh);
	116	}
a60be987 RK	117	if (buffer_uptodate(bh)) {
	118	unlock_buffer(bh);
	119	err = -EEXIST; /* internal code */
	120	goto found;
	121	}
	122	set_buffer_mapped(bh);
	123	bh->b_bdev = NILFS_I_NILFS(inode)->ns_bdev;
	124	bh->b_blocknr = pblocknr; /* set block address for read */
	125	bh->b_end_io = end_buffer_read_sync;
	126	get_bh(bh);
26dfdd8e	127	submit_bh(mode, bh);
a60be987	128	bh->b_blocknr = blocknr; /* set back to the given block address */
26dfdd8e	129	*submit_ptr = pblocknr;
a60be987 RK	130	err = 0;
	131	found:
	132	*pbh = bh;
	133
	134	out_locked:
f8e6cc01 RK	135	unlock_page(page);
f8e6cc01 RK	136	page_cache_release(page);
a60be987 RK	137	return err;
	138	}
	139
a60be987 RK	140	/**
	141	* nilfs_btnode_delete - delete B-tree node buffer
	142	* @bh: buffer to be deleted
	143	*
	144	* nilfs_btnode_delete() invalidates the specified buffer and delete the page
	145	* including the buffer if the page gets unbusy.
	146	*/
	147	void nilfs_btnode_delete(struct buffer_head *bh)
	148	{
	149	struct address_space *mapping;
	150	struct page *page = bh->b_page;
	151	pgoff_t index = page_index(page);
	152	int still_dirty;
	153
	154	page_cache_get(page);
	155	lock_page(page);
	156	wait_on_page_writeback(page);
	157
	158	nilfs_forget_buffer(bh);
	159	still_dirty = PageDirty(page);
	160	mapping = page->mapping;
	161	unlock_page(page);
	162	page_cache_release(page);
	163
	164	if (!still_dirty && mapping)
	165	invalidate_inode_pages2_range(mapping, index, index);
	166	}
	167
	168	/**
	169	* nilfs_btnode_prepare_change_key
	170	* prepare to move contents of the block for old key to one of new key.
	171	* the old buffer will not be removed, but might be reused for new buffer.
	172	* it might return -ENOMEM because of memory allocation errors,
	173	* and might return -EIO because of disk read errors.
	174	*/
	175	int nilfs_btnode_prepare_change_key(struct address_space *btnc,
	176	struct nilfs_btnode_chkey_ctxt *ctxt)
	177	{
	178	struct buffer_head obh, nbh;
	179	struct inode *inode = NILFS_BTNC_I(btnc);
	180	__u64 oldkey = ctxt->oldkey, newkey = ctxt->newkey;
	181	int err;
	182
	183	if (oldkey == newkey)
	184	return 0;
	185
	186	obh = ctxt->bh;
	187	ctxt->newbh = NULL;
	188
	189	if (inode->i_blkbits == PAGE_CACHE_SHIFT) {
	190	lock_page(obh->b_page);
	191	/*
	192	* We cannot call radix_tree_preload for the kernels older
	193	* than 2.6.23, because it is not exported for modules.
	194	*/
b1f1b8ce	195	retry:
a60be987 RK	196	err = radix_tree_preload(GFP_NOFS & ~__GFP_HIGHMEM);
	197	if (err)
	198	goto failed_unlock;
	199	/* BUG_ON(oldkey != obh->b_page->index); */
	200	if (unlikely(oldkey != obh->b_page->index))
	201	NILFS_PAGE_BUG(obh->b_page,
	202	"invalid oldkey %lld (newkey=%lld)",
	203	(unsigned long long)oldkey,
	204	(unsigned long long)newkey);
	205
a60be987 RK	206	spin_lock_irq(&btnc->tree_lock);
	207	err = radix_tree_insert(&btnc->page_tree, newkey, obh->b_page);
	208	spin_unlock_irq(&btnc->tree_lock);
	209	/*
	210	* Note: page->index will not change to newkey until
	211	* nilfs_btnode_commit_change_key() will be called.
	212	* To protect the page in intermediate state, the page lock
	213	* is held.
	214	*/
	215	radix_tree_preload_end();
	216	if (!err)
	217	return 0;
	218	else if (err != -EEXIST)
	219	goto failed_unlock;
	220
	221	err = invalidate_inode_pages2_range(btnc, newkey, newkey);
	222	if (!err)
	223	goto retry;
	224	/* fallback to copy mode */
	225	unlock_page(obh->b_page);
	226	}
	227
45f4910b RK	228	nbh = nilfs_btnode_create_block(btnc, newkey);
	229	if (!nbh)
	230	return -ENOMEM;
	231
	232	BUG_ON(nbh == obh);
	233	ctxt->newbh = nbh;
	234	return 0;
a60be987 RK	235
	236	failed_unlock:
	237	unlock_page(obh->b_page);
	238	return err;
	239	}
	240
	241	/**
	242	* nilfs_btnode_commit_change_key
	243	* commit the change_key operation prepared by prepare_change_key().
	244	*/
	245	void nilfs_btnode_commit_change_key(struct address_space *btnc,
	246	struct nilfs_btnode_chkey_ctxt *ctxt)
	247	{
	248	struct buffer_head obh = ctxt->bh, nbh = ctxt->newbh;
	249	__u64 oldkey = ctxt->oldkey, newkey = ctxt->newkey;
	250	struct page *opage;
	251
	252	if (oldkey == newkey)
	253	return;
	254
	255	if (nbh == NULL) { /* blocksize == pagesize */
	256	opage = obh->b_page;
	257	if (unlikely(oldkey != opage->index))
	258	NILFS_PAGE_BUG(opage,
	259	"invalid oldkey %lld (newkey=%lld)",
	260	(unsigned long long)oldkey,
	261	(unsigned long long)newkey);
b1e19e56	262	nilfs_btnode_mark_dirty(obh);
a60be987 RK	263
	264	spin_lock_irq(&btnc->tree_lock);
	265	radix_tree_delete(&btnc->page_tree, oldkey);
	266	radix_tree_tag_set(&btnc->page_tree, newkey,
	267	PAGECACHE_TAG_DIRTY);
	268	spin_unlock_irq(&btnc->tree_lock);
	269
	270	opage->index = obh->b_blocknr = newkey;
	271	unlock_page(opage);
	272	} else {
	273	nilfs_copy_buffer(nbh, obh);
	274	nilfs_btnode_mark_dirty(nbh);
	275
	276	nbh->b_blocknr = newkey;
	277	ctxt->bh = nbh;
	278	nilfs_btnode_delete(obh); /* will decrement bh->b_count */
	279	}
	280	}
	281
	282	/**
	283	* nilfs_btnode_abort_change_key
	284	* abort the change_key operation prepared by prepare_change_key().
	285	*/
	286	void nilfs_btnode_abort_change_key(struct address_space *btnc,
	287	struct nilfs_btnode_chkey_ctxt *ctxt)
	288	{
	289	struct buffer_head *nbh = ctxt->newbh;
	290	__u64 oldkey = ctxt->oldkey, newkey = ctxt->newkey;
	291
	292	if (oldkey == newkey)
	293	return;
	294
	295	if (nbh == NULL) { /* blocksize == pagesize */
	296	spin_lock_irq(&btnc->tree_lock);
	297	radix_tree_delete(&btnc->page_tree, newkey);
	298	spin_unlock_irq(&btnc->tree_lock);
	299	unlock_page(ctxt->bh->b_page);
	300	} else
	301	brelse(nbh);
	302	}