[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 "nilfs.h"
#include "mdt.h"
#include "dat.h"
#include "page.h"
#include "btnode.h"


void nilfs_btnode_cache_init_once(struct address_space *btnc)
{
	INIT_RADIX_TREE(&btnc->page_tree, GFP_ATOMIC);
	spin_lock_init(&btnc->tree_lock);
	INIT_LIST_HEAD(&btnc->private_list);
	spin_lock_init(&btnc->private_lock);

	spin_lock_init(&btnc->i_mmap_lock);
	INIT_RAW_PRIO_TREE_ROOT(&btnc->i_mmap);
	INIT_LIST_HEAD(&btnc->i_mmap_nonlinear);
}

static struct address_space_operations def_btnode_aops;

void nilfs_btnode_cache_init(struct address_space *btnc)
{
	btnc->host = NULL;  /* can safely set to host inode ? */
	btnc->flags = 0;
	mapping_set_gfp_mask(btnc, GFP_NOFS);
	btnc->assoc_mapping = NULL;
	btnc->backing_dev_info = &default_backing_dev_info;
	btnc->a_ops = &def_btnode_aops;
}

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

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

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

	err = -EEXIST; /* internal code */
	if (newblk) {
		if (unlikely(buffer_mapped(bh) || buffer_uptodate(bh) ||
			     buffer_dirty(bh))) {
			brelse(bh);
			BUG();
		}
		bh->b_bdev = NILFS_I_NILFS(inode)->ns_bdev;
		bh->b_blocknr = blocknr;
		set_buffer_mapped(bh);
		set_buffer_uptodate(bh);
		goto found;
	}

	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_dat_inode(NILFS_I_NILFS(inode));

			/* blocknr is a virtual block number */
			err = nilfs_dat_translate(dat, blocknr, &pblocknr);
			if (unlikely(err)) {
				brelse(bh);
				goto out_locked;
			}
		}
	}
	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(READ, bh);
	bh->b_blocknr = blocknr; /* set back to the given block address */
	err = 0;
found:
	*pbh = bh;

out_locked:
	unlock_page(bh->b_page);
	page_cache_release(bh->b_page);
	return err;
}

int nilfs_btnode_get(struct address_space *btnc, __u64 blocknr,
		     sector_t pblocknr, struct buffer_head **pbh, int newblk)
{
	struct buffer_head *bh;
	int err;

	err = nilfs_btnode_submit_block(btnc, blocknr, pblocknr, pbh, newblk);
	if (err == -EEXIST) /* internal code (cache hit) */
		return 0;
	if (unlikely(err))
		return err;

	bh = *pbh;
	wait_on_buffer(bh);
	if (!buffer_uptodate(bh)) {
		brelse(bh);
		return -EIO;
	}
	return 0;
}

/**
 * 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.
		 */
		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);

retry:
		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);
	}

	err = nilfs_btnode_get(btnc, newkey, 0, &nbh, 1);
	if (likely(!err)) {
		BUG_ON(nbh == obh);
		ctxt->newbh = nbh;
	}
	return err;

 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);
		if (!test_set_buffer_dirty(obh) && TestSetPageDirty(opage))
			BUG();

		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>
	30	#include "nilfs.h"
	31	#include "mdt.h"
	32	#include "dat.h"
	33	#include "page.h"
	34	#include "btnode.h"
	35
	36
	37	void nilfs_btnode_cache_init_once(struct address_space *btnc)
	38	{
	39	INIT_RADIX_TREE(&btnc->page_tree, GFP_ATOMIC);
	40	spin_lock_init(&btnc->tree_lock);
	41	INIT_LIST_HEAD(&btnc->private_list);
	42	spin_lock_init(&btnc->private_lock);
	43
	44	spin_lock_init(&btnc->i_mmap_lock);
	45	INIT_RAW_PRIO_TREE_ROOT(&btnc->i_mmap);
	46	INIT_LIST_HEAD(&btnc->i_mmap_nonlinear);
	47	}
	48
	49	static struct address_space_operations def_btnode_aops;
	50
	51	void nilfs_btnode_cache_init(struct address_space *btnc)
	52	{
	53	btnc->host = NULL; /* can safely set to host inode ? */
	54	btnc->flags = 0;
	55	mapping_set_gfp_mask(btnc, GFP_NOFS);
	56	btnc->assoc_mapping = NULL;
	57	btnc->backing_dev_info = &default_backing_dev_info;
	58	btnc->a_ops = &def_btnode_aops;
	59	}
	60
	61	void nilfs_btnode_cache_clear(struct address_space *btnc)
	62	{
	63	invalidate_mapping_pages(btnc, 0, -1);
	64	truncate_inode_pages(btnc, 0);
65	}
66
67	int nilfs_btnode_submit_block(struct address_space *btnc, __u64 blocknr,
68	sector_t pblocknr, struct buffer_head **pbh,
69	int newblk)
70	{
71	struct buffer_head *bh;
72	struct inode *inode = NILFS_BTNC_I(btnc);
73	int err;
74
75	bh = nilfs_grab_buffer(inode, btnc, blocknr, 1 << BH_NILFS_Node);
76	if (unlikely(!bh))
77	return -ENOMEM;
78
79	err = -EEXIST; /* internal code */
80	if (newblk) {
81	if (unlikely(buffer_mapped(bh) \|\| buffer_uptodate(bh) \|\|
82	buffer_dirty(bh))) {
83	brelse(bh);
84	BUG();
85	}
86	bh->b_bdev = NILFS_I_NILFS(inode)->ns_bdev;
87	bh->b_blocknr = blocknr;
88	set_buffer_mapped(bh);
89	set_buffer_uptodate(bh);
90	goto found;
91	}
92
93	if (buffer_uptodate(bh) \|\| buffer_dirty(bh))
94	goto found;
95
96	if (pblocknr == 0) {
97	pblocknr = blocknr;
98	if (inode->i_ino != NILFS_DAT_INO) {
99	struct inode *dat =
100	nilfs_dat_inode(NILFS_I_NILFS(inode));
101
102	/* blocknr is a virtual block number */
103	err = nilfs_dat_translate(dat, blocknr, &pblocknr);
104	if (unlikely(err)) {
105	brelse(bh);
106	goto out_locked;
107	}
108	}
109	}
110	lock_buffer(bh);
111	if (buffer_uptodate(bh)) {
112	unlock_buffer(bh);
113	err = -EEXIST; /* internal code */
114	goto found;
115	}
116	set_buffer_mapped(bh);
117	bh->b_bdev = NILFS_I_NILFS(inode)->ns_bdev;
118	bh->b_blocknr = pblocknr; /* set block address for read */
119	bh->b_end_io = end_buffer_read_sync;
120	get_bh(bh);
121	submit_bh(READ, bh);
122	bh->b_blocknr = blocknr; /* set back to the given block address */
123	err = 0;
124	found:
125	*pbh = bh;
126
127	out_locked:
128	unlock_page(bh->b_page);
129	page_cache_release(bh->b_page);
130	return err;
131	}
132
133	int nilfs_btnode_get(struct address_space *btnc, __u64 blocknr,
134	sector_t pblocknr, struct buffer_head **pbh, int newblk)
135	{
136	struct buffer_head *bh;
137	int err;
138
139	err = nilfs_btnode_submit_block(btnc, blocknr, pblocknr, pbh, newblk);
140	if (err == -EEXIST) /* internal code (cache hit) */
141	return 0;
142	if (unlikely(err))
143	return err;
144
145	bh = *pbh;
146	wait_on_buffer(bh);
147	if (!buffer_uptodate(bh)) {
148	brelse(bh);
149	return -EIO;
150	}
151	return 0;
152	}
153
154	/**
155	* nilfs_btnode_delete - delete B-tree node buffer
156	* @bh: buffer to be deleted
157	*
158	* nilfs_btnode_delete() invalidates the specified buffer and delete the page
159	* including the buffer if the page gets unbusy.
160	*/
161	void nilfs_btnode_delete(struct buffer_head *bh)
162	{
163	struct address_space *mapping;
164	struct page *page = bh->b_page;
165	pgoff_t index = page_index(page);
166	int still_dirty;
167
168	page_cache_get(page);
169	lock_page(page);
170	wait_on_page_writeback(page);
171
172	nilfs_forget_buffer(bh);
173	still_dirty = PageDirty(page);
174	mapping = page->mapping;
175	unlock_page(page);
176	page_cache_release(page);
177
178	if (!still_dirty && mapping)
179	invalidate_inode_pages2_range(mapping, index, index);
180	}
181
182	/**
183	* nilfs_btnode_prepare_change_key
184	* prepare to move contents of the block for old key to one of new key.
185	* the old buffer will not be removed, but might be reused for new buffer.
186	* it might return -ENOMEM because of memory allocation errors,
187	* and might return -EIO because of disk read errors.
188	*/
189	int nilfs_btnode_prepare_change_key(struct address_space *btnc,
190	struct nilfs_btnode_chkey_ctxt *ctxt)
191	{
192	struct buffer_head obh, nbh;
193	struct inode *inode = NILFS_BTNC_I(btnc);
194	__u64 oldkey = ctxt->oldkey, newkey = ctxt->newkey;
195	int err;
196
197	if (oldkey == newkey)
198	return 0;
199
200	obh = ctxt->bh;
201	ctxt->newbh = NULL;
202
203	if (inode->i_blkbits == PAGE_CACHE_SHIFT) {
204	lock_page(obh->b_page);
205	/*
206	* We cannot call radix_tree_preload for the kernels older
207	* than 2.6.23, because it is not exported for modules.
208	*/
209	err = radix_tree_preload(GFP_NOFS & ~__GFP_HIGHMEM);
210	if (err)
211	goto failed_unlock;
212	/* BUG_ON(oldkey != obh->b_page->index); */
213	if (unlikely(oldkey != obh->b_page->index))
214	NILFS_PAGE_BUG(obh->b_page,
215	"invalid oldkey %lld (newkey=%lld)",
216	(unsigned long long)oldkey,
217	(unsigned long long)newkey);
218
219	retry:
220	spin_lock_irq(&btnc->tree_lock);
221	err = radix_tree_insert(&btnc->page_tree, newkey, obh->b_page);
222	spin_unlock_irq(&btnc->tree_lock);
223	/*
224	* Note: page->index will not change to newkey until
225	* nilfs_btnode_commit_change_key() will be called.
226	* To protect the page in intermediate state, the page lock
227	* is held.
228	*/
229	radix_tree_preload_end();
230	if (!err)
231	return 0;
232	else if (err != -EEXIST)
233	goto failed_unlock;
234
235	err = invalidate_inode_pages2_range(btnc, newkey, newkey);
236	if (!err)
237	goto retry;
238	/* fallback to copy mode */
239	unlock_page(obh->b_page);
240	}
241
242	err = nilfs_btnode_get(btnc, newkey, 0, &nbh, 1);
243	if (likely(!err)) {
244	BUG_ON(nbh == obh);
245	ctxt->newbh = nbh;
246	}
247	return err;
248
249	failed_unlock:
250	unlock_page(obh->b_page);
251	return err;
252	}
253
254	/**
255	* nilfs_btnode_commit_change_key
256	* commit the change_key operation prepared by prepare_change_key().
257	*/
258	void nilfs_btnode_commit_change_key(struct address_space *btnc,
259	struct nilfs_btnode_chkey_ctxt *ctxt)
260	{
261	struct buffer_head obh = ctxt->bh, nbh = ctxt->newbh;
262	__u64 oldkey = ctxt->oldkey, newkey = ctxt->newkey;
263	struct page *opage;
264
265	if (oldkey == newkey)
266	return;
267
268	if (nbh == NULL) { /* blocksize == pagesize */
269	opage = obh->b_page;
270	if (unlikely(oldkey != opage->index))
271	NILFS_PAGE_BUG(opage,
272	"invalid oldkey %lld (newkey=%lld)",
273	(unsigned long long)oldkey,
274	(unsigned long long)newkey);
275	if (!test_set_buffer_dirty(obh) && TestSetPageDirty(opage))
276	BUG();
277
278	spin_lock_irq(&btnc->tree_lock);
279	radix_tree_delete(&btnc->page_tree, oldkey);
280	radix_tree_tag_set(&btnc->page_tree, newkey,
281	PAGECACHE_TAG_DIRTY);
282	spin_unlock_irq(&btnc->tree_lock);
283
284	opage->index = obh->b_blocknr = newkey;
285	unlock_page(opage);
286	} else {
287	nilfs_copy_buffer(nbh, obh);
288	nilfs_btnode_mark_dirty(nbh);
289
290	nbh->b_blocknr = newkey;
291	ctxt->bh = nbh;
292	nilfs_btnode_delete(obh); /* will decrement bh->b_count */
293	}
294	}
295
296	/**
297	* nilfs_btnode_abort_change_key
298	* abort the change_key operation prepared by prepare_change_key().
299	*/
300	void nilfs_btnode_abort_change_key(struct address_space *btnc,
301	struct nilfs_btnode_chkey_ctxt *ctxt)
302	{
303	struct buffer_head *nbh = ctxt->newbh;
304	__u64 oldkey = ctxt->oldkey, newkey = ctxt->newkey;
305
306	if (oldkey == newkey)
307	return;
308
309	if (nbh == NULL) { /* blocksize == pagesize */
310	spin_lock_irq(&btnc->tree_lock);
311	radix_tree_delete(&btnc->page_tree, newkey);
312	spin_unlock_irq(&btnc->tree_lock);
313	unlock_page(ctxt->bh->b_page);
314	} else
315	brelse(nbh);
316	}