nilfs2: move mount options to nilfs object
[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 static const struct address_space_operations def_btnode_aops = {
39         .sync_page              = block_sync_page,
40 };
41
42 void nilfs_btnode_cache_init(struct address_space *btnc,
43                              struct backing_dev_info *bdi)
44 {
45         nilfs_mapping_init(btnc, bdi, &def_btnode_aops);
46 }
47
48 void nilfs_btnode_cache_clear(struct address_space *btnc)
49 {
50         invalidate_mapping_pages(btnc, 0, -1);
51         truncate_inode_pages(btnc, 0);
52 }
53
54 struct buffer_head *
55 nilfs_btnode_create_block(struct address_space *btnc, __u64 blocknr)
56 {
57         struct inode *inode = NILFS_BTNC_I(btnc);
58         struct buffer_head *bh;
59
60         bh = nilfs_grab_buffer(inode, btnc, blocknr, 1 << BH_NILFS_Node);
61         if (unlikely(!bh))
62                 return NULL;
63
64         if (unlikely(buffer_mapped(bh) || buffer_uptodate(bh) ||
65                      buffer_dirty(bh))) {
66                 brelse(bh);
67                 BUG();
68         }
69         memset(bh->b_data, 0, 1 << inode->i_blkbits);
70         bh->b_bdev = NILFS_I_NILFS(inode)->ns_bdev;
71         bh->b_blocknr = blocknr;
72         set_buffer_mapped(bh);
73         set_buffer_uptodate(bh);
74
75         unlock_page(bh->b_page);
76         page_cache_release(bh->b_page);
77         return bh;
78 }
79
80 int nilfs_btnode_submit_block(struct address_space *btnc, __u64 blocknr,
81                               sector_t pblocknr, int mode,
82                               struct buffer_head **pbh, sector_t *submit_ptr)
83 {
84         struct buffer_head *bh;
85         struct inode *inode = NILFS_BTNC_I(btnc);
86         struct page *page;
87         int err;
88
89         bh = nilfs_grab_buffer(inode, btnc, blocknr, 1 << BH_NILFS_Node);
90         if (unlikely(!bh))
91                 return -ENOMEM;
92
93         err = -EEXIST; /* internal code */
94         page = bh->b_page;
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 = NILFS_I_NILFS(inode)->ns_dat;
103
104                         /* blocknr is a virtual block number */
105                         err = nilfs_dat_translate(dat, blocknr, &pblocknr);
106                         if (unlikely(err)) {
107                                 brelse(bh);
108                                 goto out_locked;
109                         }
110                 }
111         }
112
113         if (mode == READA) {
114                 if (pblocknr != *submit_ptr + 1 || !trylock_buffer(bh)) {
115                         err = -EBUSY; /* internal code */
116                         brelse(bh);
117                         goto out_locked;
118                 }
119         } else { /* mode == READ */
120                 lock_buffer(bh);
121         }
122         if (buffer_uptodate(bh)) {
123                 unlock_buffer(bh);
124                 err = -EEXIST; /* internal code */
125                 goto found;
126         }
127         set_buffer_mapped(bh);
128         bh->b_bdev = NILFS_I_NILFS(inode)->ns_bdev;
129         bh->b_blocknr = pblocknr; /* set block address for read */
130         bh->b_end_io = end_buffer_read_sync;
131         get_bh(bh);
132         submit_bh(mode, bh);
133         bh->b_blocknr = blocknr; /* set back to the given block address */
134         *submit_ptr = pblocknr;
135         err = 0;
136 found:
137         *pbh = bh;
138
139 out_locked:
140         unlock_page(page);
141         page_cache_release(page);
142         return err;
143 }
144
145 /**
146  * nilfs_btnode_delete - delete B-tree node buffer
147  * @bh: buffer to be deleted
148  *
149  * nilfs_btnode_delete() invalidates the specified buffer and delete the page
150  * including the buffer if the page gets unbusy.
151  */
152 void nilfs_btnode_delete(struct buffer_head *bh)
153 {
154         struct address_space *mapping;
155         struct page *page = bh->b_page;
156         pgoff_t index = page_index(page);
157         int still_dirty;
158
159         page_cache_get(page);
160         lock_page(page);
161         wait_on_page_writeback(page);
162
163         nilfs_forget_buffer(bh);
164         still_dirty = PageDirty(page);
165         mapping = page->mapping;
166         unlock_page(page);
167         page_cache_release(page);
168
169         if (!still_dirty && mapping)
170                 invalidate_inode_pages2_range(mapping, index, index);
171 }
172
173 /**
174  * nilfs_btnode_prepare_change_key
175  *  prepare to move contents of the block for old key to one of new key.
176  *  the old buffer will not be removed, but might be reused for new buffer.
177  *  it might return -ENOMEM because of memory allocation errors,
178  *  and might return -EIO because of disk read errors.
179  */
180 int nilfs_btnode_prepare_change_key(struct address_space *btnc,
181                                     struct nilfs_btnode_chkey_ctxt *ctxt)
182 {
183         struct buffer_head *obh, *nbh;
184         struct inode *inode = NILFS_BTNC_I(btnc);
185         __u64 oldkey = ctxt->oldkey, newkey = ctxt->newkey;
186         int err;
187
188         if (oldkey == newkey)
189                 return 0;
190
191         obh = ctxt->bh;
192         ctxt->newbh = NULL;
193
194         if (inode->i_blkbits == PAGE_CACHE_SHIFT) {
195                 lock_page(obh->b_page);
196                 /*
197                  * We cannot call radix_tree_preload for the kernels older
198                  * than 2.6.23, because it is not exported for modules.
199                  */
200 retry:
201                 err = radix_tree_preload(GFP_NOFS & ~__GFP_HIGHMEM);
202                 if (err)
203                         goto failed_unlock;
204                 /* BUG_ON(oldkey != obh->b_page->index); */
205                 if (unlikely(oldkey != obh->b_page->index))
206                         NILFS_PAGE_BUG(obh->b_page,
207                                        "invalid oldkey %lld (newkey=%lld)",
208                                        (unsigned long long)oldkey,
209                                        (unsigned long long)newkey);
210
211                 spin_lock_irq(&btnc->tree_lock);
212                 err = radix_tree_insert(&btnc->page_tree, newkey, obh->b_page);
213                 spin_unlock_irq(&btnc->tree_lock);
214                 /*
215                  * Note: page->index will not change to newkey until
216                  * nilfs_btnode_commit_change_key() will be called.
217                  * To protect the page in intermediate state, the page lock
218                  * is held.
219                  */
220                 radix_tree_preload_end();
221                 if (!err)
222                         return 0;
223                 else if (err != -EEXIST)
224                         goto failed_unlock;
225
226                 err = invalidate_inode_pages2_range(btnc, newkey, newkey);
227                 if (!err)
228                         goto retry;
229                 /* fallback to copy mode */
230                 unlock_page(obh->b_page);
231         }
232
233         nbh = nilfs_btnode_create_block(btnc, newkey);
234         if (!nbh)
235                 return -ENOMEM;
236
237         BUG_ON(nbh == obh);
238         ctxt->newbh = nbh;
239         return 0;
240
241  failed_unlock:
242         unlock_page(obh->b_page);
243         return err;
244 }
245
246 /**
247  * nilfs_btnode_commit_change_key
248  *  commit the change_key operation prepared by prepare_change_key().
249  */
250 void nilfs_btnode_commit_change_key(struct address_space *btnc,
251                                     struct nilfs_btnode_chkey_ctxt *ctxt)
252 {
253         struct buffer_head *obh = ctxt->bh, *nbh = ctxt->newbh;
254         __u64 oldkey = ctxt->oldkey, newkey = ctxt->newkey;
255         struct page *opage;
256
257         if (oldkey == newkey)
258                 return;
259
260         if (nbh == NULL) {      /* blocksize == pagesize */
261                 opage = obh->b_page;
262                 if (unlikely(oldkey != opage->index))
263                         NILFS_PAGE_BUG(opage,
264                                        "invalid oldkey %lld (newkey=%lld)",
265                                        (unsigned long long)oldkey,
266                                        (unsigned long long)newkey);
267                 nilfs_btnode_mark_dirty(obh);
268
269                 spin_lock_irq(&btnc->tree_lock);
270                 radix_tree_delete(&btnc->page_tree, oldkey);
271                 radix_tree_tag_set(&btnc->page_tree, newkey,
272                                    PAGECACHE_TAG_DIRTY);
273                 spin_unlock_irq(&btnc->tree_lock);
274
275                 opage->index = obh->b_blocknr = newkey;
276                 unlock_page(opage);
277         } else {
278                 nilfs_copy_buffer(nbh, obh);
279                 nilfs_btnode_mark_dirty(nbh);
280
281                 nbh->b_blocknr = newkey;
282                 ctxt->bh = nbh;
283                 nilfs_btnode_delete(obh); /* will decrement bh->b_count */
284         }
285 }
286
287 /**
288  * nilfs_btnode_abort_change_key
289  *  abort the change_key operation prepared by prepare_change_key().
290  */
291 void nilfs_btnode_abort_change_key(struct address_space *btnc,
292                                    struct nilfs_btnode_chkey_ctxt *ctxt)
293 {
294         struct buffer_head *nbh = ctxt->newbh;
295         __u64 oldkey = ctxt->oldkey, newkey = ctxt->newkey;
296
297         if (oldkey == newkey)
298                 return;
299
300         if (nbh == NULL) {      /* blocksize == pagesize */
301                 spin_lock_irq(&btnc->tree_lock);
302                 radix_tree_delete(&btnc->page_tree, newkey);
303                 spin_unlock_irq(&btnc->tree_lock);
304                 unlock_page(ctxt->bh->b_page);
305         } else
306                 brelse(nbh);
307 }