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 memset(btnc, 0, sizeof(*btnc));
40 INIT_RADIX_TREE(&btnc->page_tree, GFP_ATOMIC);
41 spin_lock_init(&btnc->tree_lock);
42 INIT_LIST_HEAD(&btnc->private_list);
43 spin_lock_init(&btnc->private_lock);
44
45 spin_lock_init(&btnc->i_mmap_lock);
46 INIT_RAW_PRIO_TREE_ROOT(&btnc->i_mmap);
47 INIT_LIST_HEAD(&btnc->i_mmap_nonlinear);
48 }
49
50 static struct address_space_operations def_btnode_aops = {
51 .sync_page = block_sync_page,
52 };
53
54 void nilfs_btnode_cache_init(struct address_space *btnc,
55 struct backing_dev_info *bdi)
56 {
57 btnc->host = NULL; /* can safely set to host inode ? */
58 btnc->flags = 0;
59 mapping_set_gfp_mask(btnc, GFP_NOFS);
60 btnc->assoc_mapping = NULL;
61 btnc->backing_dev_info = bdi;
62 btnc->a_ops = &def_btnode_aops;
63 }
64
65 void nilfs_btnode_cache_clear(struct address_space *btnc)
66 {
67 invalidate_mapping_pages(btnc, 0, -1);
68 truncate_inode_pages(btnc, 0);
69 }
70
71 int nilfs_btnode_submit_block(struct address_space *btnc, __u64 blocknr,
72 sector_t pblocknr, struct buffer_head **pbh,
73 int newblk)
74 {
75 struct buffer_head *bh;
76 struct inode *inode = NILFS_BTNC_I(btnc);
77 int err;
78
79 bh = nilfs_grab_buffer(inode, btnc, blocknr, 1 << BH_NILFS_Node);
80 if (unlikely(!bh))
81 return -ENOMEM;
82
83 err = -EEXIST; /* internal code */
84 if (newblk) {
85 if (unlikely(buffer_mapped(bh) || buffer_uptodate(bh) ||
86 buffer_dirty(bh))) {
87 brelse(bh);
88 BUG();
89 }
90 bh->b_bdev = NILFS_I_NILFS(inode)->ns_bdev;
91 bh->b_blocknr = blocknr;
92 set_buffer_mapped(bh);
93 set_buffer_uptodate(bh);
94 goto found;
95 }
96
97 if (buffer_uptodate(bh) || buffer_dirty(bh))
98 goto found;
99
100 if (pblocknr == 0) {
101 pblocknr = blocknr;
102 if (inode->i_ino != NILFS_DAT_INO) {
103 struct inode *dat =
104 nilfs_dat_inode(NILFS_I_NILFS(inode));
105
106 /* blocknr is a virtual block number */
107 err = nilfs_dat_translate(dat, blocknr, &pblocknr);
108 if (unlikely(err)) {
109 brelse(bh);
110 goto out_locked;
111 }
112 }
113 }
114 lock_buffer(bh);
115 if (buffer_uptodate(bh)) {
116 unlock_buffer(bh);
117 err = -EEXIST; /* internal code */
118 goto found;
119 }
120 set_buffer_mapped(bh);
121 bh->b_bdev = NILFS_I_NILFS(inode)->ns_bdev;
122 bh->b_blocknr = pblocknr; /* set block address for read */
123 bh->b_end_io = end_buffer_read_sync;
124 get_bh(bh);
125 submit_bh(READ, bh);
126 bh->b_blocknr = blocknr; /* set back to the given block address */
127 err = 0;
128 found:
129 *pbh = bh;
130
131 out_locked:
132 unlock_page(bh->b_page);
133 page_cache_release(bh->b_page);
134 return err;
135 }
136
137 int nilfs_btnode_get(struct address_space *btnc, __u64 blocknr,
138 sector_t pblocknr, struct buffer_head **pbh, int newblk)
139 {
140 struct buffer_head *bh;
141 int err;
142
143 err = nilfs_btnode_submit_block(btnc, blocknr, pblocknr, pbh, newblk);
144 if (err == -EEXIST) /* internal code (cache hit) */
145 return 0;
146 if (unlikely(err))
147 return err;
148
149 bh = *pbh;
150 wait_on_buffer(bh);
151 if (!buffer_uptodate(bh)) {
152 brelse(bh);
153 return -EIO;
154 }
155 return 0;
156 }
157
158 /**
159 * nilfs_btnode_delete - delete B-tree node buffer
160 * @bh: buffer to be deleted
161 *
162 * nilfs_btnode_delete() invalidates the specified buffer and delete the page
163 * including the buffer if the page gets unbusy.
164 */
165 void nilfs_btnode_delete(struct buffer_head *bh)
166 {
167 struct address_space *mapping;
168 struct page *page = bh->b_page;
169 pgoff_t index = page_index(page);
170 int still_dirty;
171
172 page_cache_get(page);
173 lock_page(page);
174 wait_on_page_writeback(page);
175
176 nilfs_forget_buffer(bh);
177 still_dirty = PageDirty(page);
178 mapping = page->mapping;
179 unlock_page(page);
180 page_cache_release(page);
181
182 if (!still_dirty && mapping)
183 invalidate_inode_pages2_range(mapping, index, index);
184 }
185
186 /**
187 * nilfs_btnode_prepare_change_key
188 * prepare to move contents of the block for old key to one of new key.
189 * the old buffer will not be removed, but might be reused for new buffer.
190 * it might return -ENOMEM because of memory allocation errors,
191 * and might return -EIO because of disk read errors.
192 */
193 int nilfs_btnode_prepare_change_key(struct address_space *btnc,
194 struct nilfs_btnode_chkey_ctxt *ctxt)
195 {
196 struct buffer_head *obh, *nbh;
197 struct inode *inode = NILFS_BTNC_I(btnc);
198 __u64 oldkey = ctxt->oldkey, newkey = ctxt->newkey;
199 int err;
200
201 if (oldkey == newkey)
202 return 0;
203
204 obh = ctxt->bh;
205 ctxt->newbh = NULL;
206
207 if (inode->i_blkbits == PAGE_CACHE_SHIFT) {
208 lock_page(obh->b_page);
209 /*
210 * We cannot call radix_tree_preload for the kernels older
211 * than 2.6.23, because it is not exported for modules.
212 */
213 retry:
214 err = radix_tree_preload(GFP_NOFS & ~__GFP_HIGHMEM);
215 if (err)
216 goto failed_unlock;
217 /* BUG_ON(oldkey != obh->b_page->index); */
218 if (unlikely(oldkey != obh->b_page->index))
219 NILFS_PAGE_BUG(obh->b_page,
220 "invalid oldkey %lld (newkey=%lld)",
221 (unsigned long long)oldkey,
222 (unsigned long long)newkey);
223
224 spin_lock_irq(&btnc->tree_lock);
225 err = radix_tree_insert(&btnc->page_tree, newkey, obh->b_page);
226 spin_unlock_irq(&btnc->tree_lock);
227 /*
228 * Note: page->index will not change to newkey until
229 * nilfs_btnode_commit_change_key() will be called.
230 * To protect the page in intermediate state, the page lock
231 * is held.
232 */
233 radix_tree_preload_end();
234 if (!err)
235 return 0;
236 else if (err != -EEXIST)
237 goto failed_unlock;
238
239 err = invalidate_inode_pages2_range(btnc, newkey, newkey);
240 if (!err)
241 goto retry;
242 /* fallback to copy mode */
243 unlock_page(obh->b_page);
244 }
245
246 err = nilfs_btnode_get(btnc, newkey, 0, &nbh, 1);
247 if (likely(!err)) {
248 BUG_ON(nbh == obh);
249 ctxt->newbh = nbh;
250 }
251 return err;
252
253 failed_unlock:
254 unlock_page(obh->b_page);
255 return err;
256 }
257
258 /**
259 * nilfs_btnode_commit_change_key
260 * commit the change_key operation prepared by prepare_change_key().
261 */
262 void nilfs_btnode_commit_change_key(struct address_space *btnc,
263 struct nilfs_btnode_chkey_ctxt *ctxt)
264 {
265 struct buffer_head *obh = ctxt->bh, *nbh = ctxt->newbh;
266 __u64 oldkey = ctxt->oldkey, newkey = ctxt->newkey;
267 struct page *opage;
268
269 if (oldkey == newkey)
270 return;
271
272 if (nbh == NULL) { /* blocksize == pagesize */
273 opage = obh->b_page;
274 if (unlikely(oldkey != opage->index))
275 NILFS_PAGE_BUG(opage,
276 "invalid oldkey %lld (newkey=%lld)",
277 (unsigned long long)oldkey,
278 (unsigned long long)newkey);
279 nilfs_btnode_mark_dirty(obh);
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 */
303 void 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 }
320
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