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-rw-r--r--fs/nilfs2/btnode.c316
1 files changed, 316 insertions, 0 deletions
diff --git a/fs/nilfs2/btnode.c b/fs/nilfs2/btnode.c
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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
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
49static struct address_space_operations def_btnode_aops;
50
51void 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
61void nilfs_btnode_cache_clear(struct address_space *btnc)
62{
63 invalidate_mapping_pages(btnc, 0, -1);
64 truncate_inode_pages(btnc, 0);
65}
66
67int 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;
124found:
125 *pbh = bh;
126
127out_locked:
128 unlock_page(bh->b_page);
129 page_cache_release(bh->b_page);
130 return err;
131}
132
133int 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 */
161void 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 */
189int 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
219retry:
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 */
258void 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 */
300void 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}
generated by cgit v1.2.2 (git 2.25.0) at 2024-12-23 01:23:47 -0500