nilfs2: unfold nilfs_dat_inode function
[linux-2.6.git] / fs / nilfs2 / btnode.c
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 <linux/gfp.h>
31 #include "nilfs.h"
32 #include "mdt.h"
33 #include "dat.h"
34 #include "page.h"
35 #include "btnode.h"
36
37
38 void nilfs_btnode_cache_init_once(struct address_space *btnc)
39 {
40         nilfs_mapping_init_once(btnc);
41 }
42
43 static const struct address_space_operations def_btnode_aops = {
44         .sync_page              = block_sync_page,
45 };
46
47 void nilfs_btnode_cache_init(struct address_space *btnc,
48                              struct backing_dev_info *bdi)
49 {
50         nilfs_mapping_init(btnc, bdi, &def_btnode_aops);
51 }
52
53 void nilfs_btnode_cache_clear(struct address_space *btnc)
54 {
55         invalidate_mapping_pages(btnc, 0, -1);
56         truncate_inode_pages(btnc, 0);
57 }
58
59 struct buffer_head *
60 nilfs_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
85 int nilfs_btnode_submit_block(struct address_space *btnc, __u64 blocknr,
86                               sector_t pblocknr, int mode,
87                               struct buffer_head **pbh, sector_t *submit_ptr)
88 {
89         struct buffer_head *bh;
90         struct inode *inode = NILFS_BTNC_I(btnc);
91         struct page *page;
92         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 */
99         page = bh->b_page;
100
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 = NILFS_I_NILFS(inode)->ns_dat;
108
109                         /* blocknr is a virtual block number */
110                         err = nilfs_dat_translate(dat, blocknr, &pblocknr);
111                         if (unlikely(err)) {
112                                 brelse(bh);
113                                 goto out_locked;
114                         }
115                 }
116         }
117
118         if (mode == READA) {
119                 if (pblocknr != *submit_ptr + 1 || !trylock_buffer(bh)) {
120                         err = -EBUSY; /* internal code */
121                         brelse(bh);
122                         goto out_locked;
123                 }
124         } else { /* mode == READ */
125                 lock_buffer(bh);
126         }
127         if (buffer_uptodate(bh)) {
128                 unlock_buffer(bh);
129                 err = -EEXIST; /* internal code */
130                 goto found;
131         }
132         set_buffer_mapped(bh);
133         bh->b_bdev = NILFS_I_NILFS(inode)->ns_bdev;
134         bh->b_blocknr = pblocknr; /* set block address for read */
135         bh->b_end_io = end_buffer_read_sync;
136         get_bh(bh);
137         submit_bh(mode, bh);
138         bh->b_blocknr = blocknr; /* set back to the given block address */
139         *submit_ptr = pblocknr;
140         err = 0;
141 found:
142         *pbh = bh;
143
144 out_locked:
145         unlock_page(page);
146         page_cache_release(page);
147         return err;
148 }
149
150 /**
151  * nilfs_btnode_delete - delete B-tree node buffer
152  * @bh: buffer to be deleted
153  *
154  * nilfs_btnode_delete() invalidates the specified buffer and delete the page
155  * including the buffer if the page gets unbusy.
156  */
157 void nilfs_btnode_delete(struct buffer_head *bh)
158 {
159         struct address_space *mapping;
160         struct page *page = bh->b_page;
161         pgoff_t index = page_index(page);
162         int still_dirty;
163
164         page_cache_get(page);
165         lock_page(page);
166         wait_on_page_writeback(page);
167
168         nilfs_forget_buffer(bh);
169         still_dirty = PageDirty(page);
170         mapping = page->mapping;
171         unlock_page(page);
172         page_cache_release(page);
173
174         if (!still_dirty && mapping)
175                 invalidate_inode_pages2_range(mapping, index, index);
176 }
177
178 /**
179  * nilfs_btnode_prepare_change_key
180  *  prepare to move contents of the block for old key to one of new key.
181  *  the old buffer will not be removed, but might be reused for new buffer.
182  *  it might return -ENOMEM because of memory allocation errors,
183  *  and might return -EIO because of disk read errors.
184  */
185 int nilfs_btnode_prepare_change_key(struct address_space *btnc,
186                                     struct nilfs_btnode_chkey_ctxt *ctxt)
187 {
188         struct buffer_head *obh, *nbh;
189         struct inode *inode = NILFS_BTNC_I(btnc);
190         __u64 oldkey = ctxt->oldkey, newkey = ctxt->newkey;
191         int err;
192
193         if (oldkey == newkey)
194                 return 0;
195
196         obh = ctxt->bh;
197         ctxt->newbh = NULL;
198
199         if (inode->i_blkbits == PAGE_CACHE_SHIFT) {
200                 lock_page(obh->b_page);
201                 /*
202                  * We cannot call radix_tree_preload for the kernels older
203                  * than 2.6.23, because it is not exported for modules.
204                  */
205 retry:
206                 err = radix_tree_preload(GFP_NOFS & ~__GFP_HIGHMEM);
207                 if (err)
208                         goto failed_unlock;
209                 /* BUG_ON(oldkey != obh->b_page->index); */
210                 if (unlikely(oldkey != obh->b_page->index))
211                         NILFS_PAGE_BUG(obh->b_page,
212                                        "invalid oldkey %lld (newkey=%lld)",
213                                        (unsigned long long)oldkey,
214                                        (unsigned long long)newkey);
215
216                 spin_lock_irq(&btnc->tree_lock);
217                 err = radix_tree_insert(&btnc->page_tree, newkey, obh->b_page);
218                 spin_unlock_irq(&btnc->tree_lock);
219                 /*
220                  * Note: page->index will not change to newkey until
221                  * nilfs_btnode_commit_change_key() will be called.
222                  * To protect the page in intermediate state, the page lock
223                  * is held.
224                  */
225                 radix_tree_preload_end();
226                 if (!err)
227                         return 0;
228                 else if (err != -EEXIST)
229                         goto failed_unlock;
230
231                 err = invalidate_inode_pages2_range(btnc, newkey, newkey);
232                 if (!err)
233                         goto retry;
234                 /* fallback to copy mode */
235                 unlock_page(obh->b_page);
236         }
237
238         nbh = nilfs_btnode_create_block(btnc, newkey);
239         if (!nbh)
240                 return -ENOMEM;
241
242         BUG_ON(nbh == obh);
243         ctxt->newbh = nbh;
244         return 0;
245
246  failed_unlock:
247         unlock_page(obh->b_page);
248         return err;
249 }
250
251 /**
252  * nilfs_btnode_commit_change_key
253  *  commit the change_key operation prepared by prepare_change_key().
254  */
255 void nilfs_btnode_commit_change_key(struct address_space *btnc,
256                                     struct nilfs_btnode_chkey_ctxt *ctxt)
257 {
258         struct buffer_head *obh = ctxt->bh, *nbh = ctxt->newbh;
259         __u64 oldkey = ctxt->oldkey, newkey = ctxt->newkey;
260         struct page *opage;
261
262         if (oldkey == newkey)
263                 return;
264
265         if (nbh == NULL) {      /* blocksize == pagesize */
266                 opage = obh->b_page;
267                 if (unlikely(oldkey != opage->index))
268                         NILFS_PAGE_BUG(opage,
269                                        "invalid oldkey %lld (newkey=%lld)",
270                                        (unsigned long long)oldkey,
271                                        (unsigned long long)newkey);
272                 nilfs_btnode_mark_dirty(obh);
273
274                 spin_lock_irq(&btnc->tree_lock);
275                 radix_tree_delete(&btnc->page_tree, oldkey);
276                 radix_tree_tag_set(&btnc->page_tree, newkey,
277                                    PAGECACHE_TAG_DIRTY);
278                 spin_unlock_irq(&btnc->tree_lock);
279
280                 opage->index = obh->b_blocknr = newkey;
281                 unlock_page(opage);
282         } else {
283                 nilfs_copy_buffer(nbh, obh);
284                 nilfs_btnode_mark_dirty(nbh);
285
286                 nbh->b_blocknr = newkey;
287                 ctxt->bh = nbh;
288                 nilfs_btnode_delete(obh); /* will decrement bh->b_count */
289         }
290 }
291
292 /**
293  * nilfs_btnode_abort_change_key
294  *  abort the change_key operation prepared by prepare_change_key().
295  */
296 void nilfs_btnode_abort_change_key(struct address_space *btnc,
297                                    struct nilfs_btnode_chkey_ctxt *ctxt)
298 {
299         struct buffer_head *nbh = ctxt->newbh;
300         __u64 oldkey = ctxt->oldkey, newkey = ctxt->newkey;
301
302         if (oldkey == newkey)
303                 return;
304
305         if (nbh == NULL) {      /* blocksize == pagesize */
306                 spin_lock_irq(&btnc->tree_lock);
307                 radix_tree_delete(&btnc->page_tree, newkey);
308                 spin_unlock_irq(&btnc->tree_lock);
309                 unlock_page(ctxt->bh->b_page);
310         } else
311                 brelse(nbh);
312 }