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Ryusuke Konishia60be982009-04-06 19:01:25 -07001/*
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>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090030#include <linux/gfp.h>
Ryusuke Konishia60be982009-04-06 19:01:25 -070031#include "nilfs.h"
32#include "mdt.h"
33#include "dat.h"
34#include "page.h"
35#include "btnode.h"
36
Ryusuke Konishia53b4752009-05-27 22:11:46 +090037void nilfs_btnode_cache_init(struct address_space *btnc,
38 struct backing_dev_info *bdi)
Ryusuke Konishia60be982009-04-06 19:01:25 -070039{
Jens Axboe7eaceac2011-03-10 08:52:07 +010040 nilfs_mapping_init(btnc, bdi);
Ryusuke Konishia60be982009-04-06 19:01:25 -070041}
42
43void nilfs_btnode_cache_clear(struct address_space *btnc)
44{
45 invalidate_mapping_pages(btnc, 0, -1);
46 truncate_inode_pages(btnc, 0);
47}
48
Ryusuke Konishid501d732009-11-13 16:04:11 +090049struct buffer_head *
50nilfs_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
Ryusuke Konishia60be982009-04-06 19:01:25 -070075int nilfs_btnode_submit_block(struct address_space *btnc, __u64 blocknr,
Ryusuke Konishi26dfdd82010-07-18 10:42:23 +090076 sector_t pblocknr, int mode,
77 struct buffer_head **pbh, sector_t *submit_ptr)
Ryusuke Konishia60be982009-04-06 19:01:25 -070078{
79 struct buffer_head *bh;
80 struct inode *inode = NILFS_BTNC_I(btnc);
Ryusuke Konishif8e6cc02010-07-15 11:39:10 +090081 struct page *page;
Ryusuke Konishia60be982009-04-06 19:01:25 -070082 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 */
Ryusuke Konishif8e6cc02010-07-15 11:39:10 +090089 page = bh->b_page;
Ryusuke Konishia60be982009-04-06 19:01:25 -070090
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) {
Ryusuke Konishi365e2152010-12-27 00:07:30 +090097 struct inode *dat = NILFS_I_NILFS(inode)->ns_dat;
Ryusuke Konishia60be982009-04-06 19:01:25 -070098
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 }
Ryusuke Konishi26dfdd82010-07-18 10:42:23 +0900107
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 }
Ryusuke Konishia60be982009-04-06 19:01:25 -0700117 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);
Ryusuke Konishi26dfdd82010-07-18 10:42:23 +0900127 submit_bh(mode, bh);
Ryusuke Konishia60be982009-04-06 19:01:25 -0700128 bh->b_blocknr = blocknr; /* set back to the given block address */
Ryusuke Konishi26dfdd82010-07-18 10:42:23 +0900129 *submit_ptr = pblocknr;
Ryusuke Konishia60be982009-04-06 19:01:25 -0700130 err = 0;
131found:
132 *pbh = bh;
133
134out_locked:
Ryusuke Konishif8e6cc02010-07-15 11:39:10 +0900135 unlock_page(page);
136 page_cache_release(page);
Ryusuke Konishia60be982009-04-06 19:01:25 -0700137 return err;
138}
139
Ryusuke Konishia60be982009-04-06 19:01:25 -0700140/**
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 */
147void 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 */
175int 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 */
Ryusuke Konishib1f1b8c2009-08-30 04:21:41 +0900195retry:
Ryusuke Konishia60be982009-04-06 19:01:25 -0700196 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
Ryusuke Konishia60be982009-04-06 19:01:25 -0700206 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
Ryusuke Konishi45f49102009-11-13 16:25:19 +0900228 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;
Ryusuke Konishia60be982009-04-06 19:01:25 -0700235
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 */
245void 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);
Ryusuke Konishib1e19e52009-11-03 00:25:53 +0900262 nilfs_btnode_mark_dirty(obh);
Ryusuke Konishia60be982009-04-06 19:01:25 -0700263
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 */
286void 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}