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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
37
38void nilfs_btnode_cache_init_once(struct address_space *btnc)
39{
Ryusuke Konishiebdfed42010-09-06 12:05:43 +090040 nilfs_mapping_init_once(btnc);
Ryusuke Konishia60be982009-04-06 19:01:25 -070041}
42
Alexey Dobriyan7f094102009-09-21 17:01:10 -070043static const struct address_space_operations def_btnode_aops = {
Ryusuke Konishifa032742009-05-27 22:44:34 +090044 .sync_page = block_sync_page,
45};
Ryusuke Konishia60be982009-04-06 19:01:25 -070046
Ryusuke Konishia53b4752009-05-27 22:11:46 +090047void nilfs_btnode_cache_init(struct address_space *btnc,
48 struct backing_dev_info *bdi)
Ryusuke Konishia60be982009-04-06 19:01:25 -070049{
Ryusuke Konishiebdfed42010-09-06 12:05:43 +090050 nilfs_mapping_init(btnc, bdi, &def_btnode_aops);
Ryusuke Konishia60be982009-04-06 19:01:25 -070051}
52
53void nilfs_btnode_cache_clear(struct address_space *btnc)
54{
55 invalidate_mapping_pages(btnc, 0, -1);
56 truncate_inode_pages(btnc, 0);
57}
58
Ryusuke Konishid501d732009-11-13 16:04:11 +090059struct buffer_head *
60nilfs_btnode_create_block(struct address_space *btnc, __u64 blocknr)
61{
62 struct inode *inode = NILFS_BTNC_I(btnc);
63 struct buffer_head *bh;
64
65 bh = nilfs_grab_buffer(inode, btnc, blocknr, 1 << BH_NILFS_Node);
66 if (unlikely(!bh))
67 return NULL;
68
69 if (unlikely(buffer_mapped(bh) || buffer_uptodate(bh) ||
70 buffer_dirty(bh))) {
71 brelse(bh);
72 BUG();
73 }
74 memset(bh->b_data, 0, 1 << inode->i_blkbits);
75 bh->b_bdev = NILFS_I_NILFS(inode)->ns_bdev;
76 bh->b_blocknr = blocknr;
77 set_buffer_mapped(bh);
78 set_buffer_uptodate(bh);
79
80 unlock_page(bh->b_page);
81 page_cache_release(bh->b_page);
82 return bh;
83}
84
Ryusuke Konishia60be982009-04-06 19:01:25 -070085int nilfs_btnode_submit_block(struct address_space *btnc, __u64 blocknr,
Ryusuke Konishi26dfdd82010-07-18 10:42:23 +090086 sector_t pblocknr, int mode,
87 struct buffer_head **pbh, sector_t *submit_ptr)
Ryusuke Konishia60be982009-04-06 19:01:25 -070088{
89 struct buffer_head *bh;
90 struct inode *inode = NILFS_BTNC_I(btnc);
Ryusuke Konishif8e6cc02010-07-15 11:39:10 +090091 struct page *page;
Ryusuke Konishia60be982009-04-06 19:01:25 -070092 int err;
93
94 bh = nilfs_grab_buffer(inode, btnc, blocknr, 1 << BH_NILFS_Node);
95 if (unlikely(!bh))
96 return -ENOMEM;
97
98 err = -EEXIST; /* internal code */
Ryusuke Konishif8e6cc02010-07-15 11:39:10 +090099 page = bh->b_page;
Ryusuke Konishia60be982009-04-06 19:01:25 -0700100
101 if (buffer_uptodate(bh) || buffer_dirty(bh))
102 goto found;
103
104 if (pblocknr == 0) {
105 pblocknr = blocknr;
106 if (inode->i_ino != NILFS_DAT_INO) {
107 struct inode *dat =
108 nilfs_dat_inode(NILFS_I_NILFS(inode));
109
110 /* blocknr is a virtual block number */
111 err = nilfs_dat_translate(dat, blocknr, &pblocknr);
112 if (unlikely(err)) {
113 brelse(bh);
114 goto out_locked;
115 }
116 }
117 }
Ryusuke Konishi26dfdd82010-07-18 10:42:23 +0900118
119 if (mode == READA) {
120 if (pblocknr != *submit_ptr + 1 || !trylock_buffer(bh)) {
121 err = -EBUSY; /* internal code */
122 brelse(bh);
123 goto out_locked;
124 }
125 } else { /* mode == READ */
126 lock_buffer(bh);
127 }
Ryusuke Konishia60be982009-04-06 19:01:25 -0700128 if (buffer_uptodate(bh)) {
129 unlock_buffer(bh);
130 err = -EEXIST; /* internal code */
131 goto found;
132 }
133 set_buffer_mapped(bh);
134 bh->b_bdev = NILFS_I_NILFS(inode)->ns_bdev;
135 bh->b_blocknr = pblocknr; /* set block address for read */
136 bh->b_end_io = end_buffer_read_sync;
137 get_bh(bh);
Ryusuke Konishi26dfdd82010-07-18 10:42:23 +0900138 submit_bh(mode, bh);
Ryusuke Konishia60be982009-04-06 19:01:25 -0700139 bh->b_blocknr = blocknr; /* set back to the given block address */
Ryusuke Konishi26dfdd82010-07-18 10:42:23 +0900140 *submit_ptr = pblocknr;
Ryusuke Konishia60be982009-04-06 19:01:25 -0700141 err = 0;
142found:
143 *pbh = bh;
144
145out_locked:
Ryusuke Konishif8e6cc02010-07-15 11:39:10 +0900146 unlock_page(page);
147 page_cache_release(page);
Ryusuke Konishia60be982009-04-06 19:01:25 -0700148 return err;
149}
150
Ryusuke Konishia60be982009-04-06 19:01:25 -0700151/**
152 * nilfs_btnode_delete - delete B-tree node buffer
153 * @bh: buffer to be deleted
154 *
155 * nilfs_btnode_delete() invalidates the specified buffer and delete the page
156 * including the buffer if the page gets unbusy.
157 */
158void nilfs_btnode_delete(struct buffer_head *bh)
159{
160 struct address_space *mapping;
161 struct page *page = bh->b_page;
162 pgoff_t index = page_index(page);
163 int still_dirty;
164
165 page_cache_get(page);
166 lock_page(page);
167 wait_on_page_writeback(page);
168
169 nilfs_forget_buffer(bh);
170 still_dirty = PageDirty(page);
171 mapping = page->mapping;
172 unlock_page(page);
173 page_cache_release(page);
174
175 if (!still_dirty && mapping)
176 invalidate_inode_pages2_range(mapping, index, index);
177}
178
179/**
180 * nilfs_btnode_prepare_change_key
181 * prepare to move contents of the block for old key to one of new key.
182 * the old buffer will not be removed, but might be reused for new buffer.
183 * it might return -ENOMEM because of memory allocation errors,
184 * and might return -EIO because of disk read errors.
185 */
186int nilfs_btnode_prepare_change_key(struct address_space *btnc,
187 struct nilfs_btnode_chkey_ctxt *ctxt)
188{
189 struct buffer_head *obh, *nbh;
190 struct inode *inode = NILFS_BTNC_I(btnc);
191 __u64 oldkey = ctxt->oldkey, newkey = ctxt->newkey;
192 int err;
193
194 if (oldkey == newkey)
195 return 0;
196
197 obh = ctxt->bh;
198 ctxt->newbh = NULL;
199
200 if (inode->i_blkbits == PAGE_CACHE_SHIFT) {
201 lock_page(obh->b_page);
202 /*
203 * We cannot call radix_tree_preload for the kernels older
204 * than 2.6.23, because it is not exported for modules.
205 */
Ryusuke Konishib1f1b8c2009-08-30 04:21:41 +0900206retry:
Ryusuke Konishia60be982009-04-06 19:01:25 -0700207 err = radix_tree_preload(GFP_NOFS & ~__GFP_HIGHMEM);
208 if (err)
209 goto failed_unlock;
210 /* BUG_ON(oldkey != obh->b_page->index); */
211 if (unlikely(oldkey != obh->b_page->index))
212 NILFS_PAGE_BUG(obh->b_page,
213 "invalid oldkey %lld (newkey=%lld)",
214 (unsigned long long)oldkey,
215 (unsigned long long)newkey);
216
Ryusuke Konishia60be982009-04-06 19:01:25 -0700217 spin_lock_irq(&btnc->tree_lock);
218 err = radix_tree_insert(&btnc->page_tree, newkey, obh->b_page);
219 spin_unlock_irq(&btnc->tree_lock);
220 /*
221 * Note: page->index will not change to newkey until
222 * nilfs_btnode_commit_change_key() will be called.
223 * To protect the page in intermediate state, the page lock
224 * is held.
225 */
226 radix_tree_preload_end();
227 if (!err)
228 return 0;
229 else if (err != -EEXIST)
230 goto failed_unlock;
231
232 err = invalidate_inode_pages2_range(btnc, newkey, newkey);
233 if (!err)
234 goto retry;
235 /* fallback to copy mode */
236 unlock_page(obh->b_page);
237 }
238
Ryusuke Konishi45f49102009-11-13 16:25:19 +0900239 nbh = nilfs_btnode_create_block(btnc, newkey);
240 if (!nbh)
241 return -ENOMEM;
242
243 BUG_ON(nbh == obh);
244 ctxt->newbh = nbh;
245 return 0;
Ryusuke Konishia60be982009-04-06 19:01:25 -0700246
247 failed_unlock:
248 unlock_page(obh->b_page);
249 return err;
250}
251
252/**
253 * nilfs_btnode_commit_change_key
254 * commit the change_key operation prepared by prepare_change_key().
255 */
256void nilfs_btnode_commit_change_key(struct address_space *btnc,
257 struct nilfs_btnode_chkey_ctxt *ctxt)
258{
259 struct buffer_head *obh = ctxt->bh, *nbh = ctxt->newbh;
260 __u64 oldkey = ctxt->oldkey, newkey = ctxt->newkey;
261 struct page *opage;
262
263 if (oldkey == newkey)
264 return;
265
266 if (nbh == NULL) { /* blocksize == pagesize */
267 opage = obh->b_page;
268 if (unlikely(oldkey != opage->index))
269 NILFS_PAGE_BUG(opage,
270 "invalid oldkey %lld (newkey=%lld)",
271 (unsigned long long)oldkey,
272 (unsigned long long)newkey);
Ryusuke Konishib1e19e52009-11-03 00:25:53 +0900273 nilfs_btnode_mark_dirty(obh);
Ryusuke Konishia60be982009-04-06 19:01:25 -0700274
275 spin_lock_irq(&btnc->tree_lock);
276 radix_tree_delete(&btnc->page_tree, oldkey);
277 radix_tree_tag_set(&btnc->page_tree, newkey,
278 PAGECACHE_TAG_DIRTY);
279 spin_unlock_irq(&btnc->tree_lock);
280
281 opage->index = obh->b_blocknr = newkey;
282 unlock_page(opage);
283 } else {
284 nilfs_copy_buffer(nbh, obh);
285 nilfs_btnode_mark_dirty(nbh);
286
287 nbh->b_blocknr = newkey;
288 ctxt->bh = nbh;
289 nilfs_btnode_delete(obh); /* will decrement bh->b_count */
290 }
291}
292
293/**
294 * nilfs_btnode_abort_change_key
295 * abort the change_key operation prepared by prepare_change_key().
296 */
297void nilfs_btnode_abort_change_key(struct address_space *btnc,
298 struct nilfs_btnode_chkey_ctxt *ctxt)
299{
300 struct buffer_head *nbh = ctxt->newbh;
301 __u64 oldkey = ctxt->oldkey, newkey = ctxt->newkey;
302
303 if (oldkey == newkey)
304 return;
305
306 if (nbh == NULL) { /* blocksize == pagesize */
307 spin_lock_irq(&btnc->tree_lock);
308 radix_tree_delete(&btnc->page_tree, newkey);
309 spin_unlock_irq(&btnc->tree_lock);
310 unlock_page(ctxt->bh->b_page);
311 } else
312 brelse(nbh);
313}