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a60be987 RK |
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 | 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 | ||
49 | static struct address_space_operations def_btnode_aops; | |
50 | ||
51 | void 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 | ||
61 | void nilfs_btnode_cache_clear(struct address_space *btnc) | |
62 | { | |
63 | invalidate_mapping_pages(btnc, 0, -1); | |
64 | truncate_inode_pages(btnc, 0); | |
65 | } | |
66 | ||
67 | int 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; | |
124 | found: | |
125 | *pbh = bh; | |
126 | ||
127 | out_locked: | |
128 | unlock_page(bh->b_page); | |
129 | page_cache_release(bh->b_page); | |
130 | return err; | |
131 | } | |
132 | ||
133 | int 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 | */ | |
161 | void 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 | */ | |
189 | int 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 | ||
219 | retry: | |
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 | */ | |
258 | void 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 | */ | |
300 | void 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 | } |