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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>
30#include "nilfs.h"
31#include "mdt.h"
32#include "dat.h"
33#include "page.h"
34#include "btnode.h"
35
36
37void 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
Ryusuke Konishifa032742009-05-27 22:44:34 +090049static struct address_space_operations def_btnode_aops = {
50 .sync_page = block_sync_page,
51};
Ryusuke Konishia60be982009-04-06 19:01:25 -070052
Ryusuke Konishia53b4752009-05-27 22:11:46 +090053void nilfs_btnode_cache_init(struct address_space *btnc,
54 struct backing_dev_info *bdi)
Ryusuke Konishia60be982009-04-06 19:01:25 -070055{
56 btnc->host = NULL; /* can safely set to host inode ? */
57 btnc->flags = 0;
58 mapping_set_gfp_mask(btnc, GFP_NOFS);
59 btnc->assoc_mapping = NULL;
Ryusuke Konishia53b4752009-05-27 22:11:46 +090060 btnc->backing_dev_info = bdi;
Ryusuke Konishia60be982009-04-06 19:01:25 -070061 btnc->a_ops = &def_btnode_aops;
62}
63
64void nilfs_btnode_cache_clear(struct address_space *btnc)
65{
66 invalidate_mapping_pages(btnc, 0, -1);
67 truncate_inode_pages(btnc, 0);
68}
69
70int nilfs_btnode_submit_block(struct address_space *btnc, __u64 blocknr,
71 sector_t pblocknr, struct buffer_head **pbh,
72 int newblk)
73{
74 struct buffer_head *bh;
75 struct inode *inode = NILFS_BTNC_I(btnc);
76 int err;
77
78 bh = nilfs_grab_buffer(inode, btnc, blocknr, 1 << BH_NILFS_Node);
79 if (unlikely(!bh))
80 return -ENOMEM;
81
82 err = -EEXIST; /* internal code */
83 if (newblk) {
84 if (unlikely(buffer_mapped(bh) || buffer_uptodate(bh) ||
85 buffer_dirty(bh))) {
86 brelse(bh);
87 BUG();
88 }
89 bh->b_bdev = NILFS_I_NILFS(inode)->ns_bdev;
90 bh->b_blocknr = blocknr;
91 set_buffer_mapped(bh);
92 set_buffer_uptodate(bh);
93 goto found;
94 }
95
96 if (buffer_uptodate(bh) || buffer_dirty(bh))
97 goto found;
98
99 if (pblocknr == 0) {
100 pblocknr = blocknr;
101 if (inode->i_ino != NILFS_DAT_INO) {
102 struct inode *dat =
103 nilfs_dat_inode(NILFS_I_NILFS(inode));
104
105 /* blocknr is a virtual block number */
106 err = nilfs_dat_translate(dat, blocknr, &pblocknr);
107 if (unlikely(err)) {
108 brelse(bh);
109 goto out_locked;
110 }
111 }
112 }
113 lock_buffer(bh);
114 if (buffer_uptodate(bh)) {
115 unlock_buffer(bh);
116 err = -EEXIST; /* internal code */
117 goto found;
118 }
119 set_buffer_mapped(bh);
120 bh->b_bdev = NILFS_I_NILFS(inode)->ns_bdev;
121 bh->b_blocknr = pblocknr; /* set block address for read */
122 bh->b_end_io = end_buffer_read_sync;
123 get_bh(bh);
124 submit_bh(READ, bh);
125 bh->b_blocknr = blocknr; /* set back to the given block address */
126 err = 0;
127found:
128 *pbh = bh;
129
130out_locked:
131 unlock_page(bh->b_page);
132 page_cache_release(bh->b_page);
133 return err;
134}
135
136int nilfs_btnode_get(struct address_space *btnc, __u64 blocknr,
137 sector_t pblocknr, struct buffer_head **pbh, int newblk)
138{
139 struct buffer_head *bh;
140 int err;
141
142 err = nilfs_btnode_submit_block(btnc, blocknr, pblocknr, pbh, newblk);
143 if (err == -EEXIST) /* internal code (cache hit) */
144 return 0;
145 if (unlikely(err))
146 return err;
147
148 bh = *pbh;
149 wait_on_buffer(bh);
150 if (!buffer_uptodate(bh)) {
151 brelse(bh);
152 return -EIO;
153 }
154 return 0;
155}
156
157/**
158 * nilfs_btnode_delete - delete B-tree node buffer
159 * @bh: buffer to be deleted
160 *
161 * nilfs_btnode_delete() invalidates the specified buffer and delete the page
162 * including the buffer if the page gets unbusy.
163 */
164void nilfs_btnode_delete(struct buffer_head *bh)
165{
166 struct address_space *mapping;
167 struct page *page = bh->b_page;
168 pgoff_t index = page_index(page);
169 int still_dirty;
170
171 page_cache_get(page);
172 lock_page(page);
173 wait_on_page_writeback(page);
174
175 nilfs_forget_buffer(bh);
176 still_dirty = PageDirty(page);
177 mapping = page->mapping;
178 unlock_page(page);
179 page_cache_release(page);
180
181 if (!still_dirty && mapping)
182 invalidate_inode_pages2_range(mapping, index, index);
183}
184
185/**
186 * nilfs_btnode_prepare_change_key
187 * prepare to move contents of the block for old key to one of new key.
188 * the old buffer will not be removed, but might be reused for new buffer.
189 * it might return -ENOMEM because of memory allocation errors,
190 * and might return -EIO because of disk read errors.
191 */
192int nilfs_btnode_prepare_change_key(struct address_space *btnc,
193 struct nilfs_btnode_chkey_ctxt *ctxt)
194{
195 struct buffer_head *obh, *nbh;
196 struct inode *inode = NILFS_BTNC_I(btnc);
197 __u64 oldkey = ctxt->oldkey, newkey = ctxt->newkey;
198 int err;
199
200 if (oldkey == newkey)
201 return 0;
202
203 obh = ctxt->bh;
204 ctxt->newbh = NULL;
205
206 if (inode->i_blkbits == PAGE_CACHE_SHIFT) {
207 lock_page(obh->b_page);
208 /*
209 * We cannot call radix_tree_preload for the kernels older
210 * than 2.6.23, because it is not exported for modules.
211 */
Ryusuke Konishib1f1b8c2009-08-30 04:21:41 +0900212retry:
Ryusuke Konishia60be982009-04-06 19:01:25 -0700213 err = radix_tree_preload(GFP_NOFS & ~__GFP_HIGHMEM);
214 if (err)
215 goto failed_unlock;
216 /* BUG_ON(oldkey != obh->b_page->index); */
217 if (unlikely(oldkey != obh->b_page->index))
218 NILFS_PAGE_BUG(obh->b_page,
219 "invalid oldkey %lld (newkey=%lld)",
220 (unsigned long long)oldkey,
221 (unsigned long long)newkey);
222
Ryusuke Konishia60be982009-04-06 19:01:25 -0700223 spin_lock_irq(&btnc->tree_lock);
224 err = radix_tree_insert(&btnc->page_tree, newkey, obh->b_page);
225 spin_unlock_irq(&btnc->tree_lock);
226 /*
227 * Note: page->index will not change to newkey until
228 * nilfs_btnode_commit_change_key() will be called.
229 * To protect the page in intermediate state, the page lock
230 * is held.
231 */
232 radix_tree_preload_end();
233 if (!err)
234 return 0;
235 else if (err != -EEXIST)
236 goto failed_unlock;
237
238 err = invalidate_inode_pages2_range(btnc, newkey, newkey);
239 if (!err)
240 goto retry;
241 /* fallback to copy mode */
242 unlock_page(obh->b_page);
243 }
244
245 err = nilfs_btnode_get(btnc, newkey, 0, &nbh, 1);
246 if (likely(!err)) {
247 BUG_ON(nbh == obh);
248 ctxt->newbh = nbh;
249 }
250 return err;
251
252 failed_unlock:
253 unlock_page(obh->b_page);
254 return err;
255}
256
257/**
258 * nilfs_btnode_commit_change_key
259 * commit the change_key operation prepared by prepare_change_key().
260 */
261void nilfs_btnode_commit_change_key(struct address_space *btnc,
262 struct nilfs_btnode_chkey_ctxt *ctxt)
263{
264 struct buffer_head *obh = ctxt->bh, *nbh = ctxt->newbh;
265 __u64 oldkey = ctxt->oldkey, newkey = ctxt->newkey;
266 struct page *opage;
267
268 if (oldkey == newkey)
269 return;
270
271 if (nbh == NULL) { /* blocksize == pagesize */
272 opage = obh->b_page;
273 if (unlikely(oldkey != opage->index))
274 NILFS_PAGE_BUG(opage,
275 "invalid oldkey %lld (newkey=%lld)",
276 (unsigned long long)oldkey,
277 (unsigned long long)newkey);
278 if (!test_set_buffer_dirty(obh) && TestSetPageDirty(opage))
279 BUG();
280
281 spin_lock_irq(&btnc->tree_lock);
282 radix_tree_delete(&btnc->page_tree, oldkey);
283 radix_tree_tag_set(&btnc->page_tree, newkey,
284 PAGECACHE_TAG_DIRTY);
285 spin_unlock_irq(&btnc->tree_lock);
286
287 opage->index = obh->b_blocknr = newkey;
288 unlock_page(opage);
289 } else {
290 nilfs_copy_buffer(nbh, obh);
291 nilfs_btnode_mark_dirty(nbh);
292
293 nbh->b_blocknr = newkey;
294 ctxt->bh = nbh;
295 nilfs_btnode_delete(obh); /* will decrement bh->b_count */
296 }
297}
298
299/**
300 * nilfs_btnode_abort_change_key
301 * abort the change_key operation prepared by prepare_change_key().
302 */
303void nilfs_btnode_abort_change_key(struct address_space *btnc,
304 struct nilfs_btnode_chkey_ctxt *ctxt)
305{
306 struct buffer_head *nbh = ctxt->newbh;
307 __u64 oldkey = ctxt->oldkey, newkey = ctxt->newkey;
308
309 if (oldkey == newkey)
310 return;
311
312 if (nbh == NULL) { /* blocksize == pagesize */
313 spin_lock_irq(&btnc->tree_lock);
314 radix_tree_delete(&btnc->page_tree, newkey);
315 spin_unlock_irq(&btnc->tree_lock);
316 unlock_page(ctxt->bh->b_page);
317 } else
318 brelse(nbh);
319}