2 * btnode.c - NILFS B-tree node cache
4 * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
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.
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.
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
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.
26 #include <linux/types.h>
27 #include <linux/buffer_head.h>
29 #include <linux/backing-dev.h>
30 #include <linux/gfp.h>
38 void nilfs_btnode_cache_init_once(struct address_space
*btnc
)
40 nilfs_mapping_init_once(btnc
);
43 void nilfs_btnode_cache_init(struct address_space
*btnc
,
44 struct backing_dev_info
*bdi
)
46 nilfs_mapping_init(btnc
, bdi
);
49 void nilfs_btnode_cache_clear(struct address_space
*btnc
)
51 invalidate_mapping_pages(btnc
, 0, -1);
52 truncate_inode_pages(btnc
, 0);
56 nilfs_btnode_create_block(struct address_space
*btnc
, __u64 blocknr
)
58 struct inode
*inode
= NILFS_BTNC_I(btnc
);
59 struct buffer_head
*bh
;
61 bh
= nilfs_grab_buffer(inode
, btnc
, blocknr
, 1 << BH_NILFS_Node
);
65 if (unlikely(buffer_mapped(bh
) || buffer_uptodate(bh
) ||
70 memset(bh
->b_data
, 0, 1 << inode
->i_blkbits
);
71 bh
->b_bdev
= NILFS_I_NILFS(inode
)->ns_bdev
;
72 bh
->b_blocknr
= blocknr
;
73 set_buffer_mapped(bh
);
74 set_buffer_uptodate(bh
);
76 unlock_page(bh
->b_page
);
77 page_cache_release(bh
->b_page
);
81 int nilfs_btnode_submit_block(struct address_space
*btnc
, __u64 blocknr
,
82 sector_t pblocknr
, int mode
,
83 struct buffer_head
**pbh
, sector_t
*submit_ptr
)
85 struct buffer_head
*bh
;
86 struct inode
*inode
= NILFS_BTNC_I(btnc
);
90 bh
= nilfs_grab_buffer(inode
, btnc
, blocknr
, 1 << BH_NILFS_Node
);
94 err
= -EEXIST
; /* internal code */
97 if (buffer_uptodate(bh
) || buffer_dirty(bh
))
102 if (inode
->i_ino
!= NILFS_DAT_INO
) {
103 struct inode
*dat
= NILFS_I_NILFS(inode
)->ns_dat
;
105 /* blocknr is a virtual block number */
106 err
= nilfs_dat_translate(dat
, blocknr
, &pblocknr
);
115 if (pblocknr
!= *submit_ptr
+ 1 || !trylock_buffer(bh
)) {
116 err
= -EBUSY
; /* internal code */
120 } else { /* mode == READ */
123 if (buffer_uptodate(bh
)) {
125 err
= -EEXIST
; /* internal code */
128 set_buffer_mapped(bh
);
129 bh
->b_bdev
= NILFS_I_NILFS(inode
)->ns_bdev
;
130 bh
->b_blocknr
= pblocknr
; /* set block address for read */
131 bh
->b_end_io
= end_buffer_read_sync
;
134 bh
->b_blocknr
= blocknr
; /* set back to the given block address */
135 *submit_ptr
= pblocknr
;
142 page_cache_release(page
);
147 * nilfs_btnode_delete - delete B-tree node buffer
148 * @bh: buffer to be deleted
150 * nilfs_btnode_delete() invalidates the specified buffer and delete the page
151 * including the buffer if the page gets unbusy.
153 void nilfs_btnode_delete(struct buffer_head
*bh
)
155 struct address_space
*mapping
;
156 struct page
*page
= bh
->b_page
;
157 pgoff_t index
= page_index(page
);
160 page_cache_get(page
);
162 wait_on_page_writeback(page
);
164 nilfs_forget_buffer(bh
);
165 still_dirty
= PageDirty(page
);
166 mapping
= page
->mapping
;
168 page_cache_release(page
);
170 if (!still_dirty
&& mapping
)
171 invalidate_inode_pages2_range(mapping
, index
, index
);
175 * nilfs_btnode_prepare_change_key
176 * prepare to move contents of the block for old key to one of new key.
177 * the old buffer will not be removed, but might be reused for new buffer.
178 * it might return -ENOMEM because of memory allocation errors,
179 * and might return -EIO because of disk read errors.
181 int nilfs_btnode_prepare_change_key(struct address_space
*btnc
,
182 struct nilfs_btnode_chkey_ctxt
*ctxt
)
184 struct buffer_head
*obh
, *nbh
;
185 struct inode
*inode
= NILFS_BTNC_I(btnc
);
186 __u64 oldkey
= ctxt
->oldkey
, newkey
= ctxt
->newkey
;
189 if (oldkey
== newkey
)
195 if (inode
->i_blkbits
== PAGE_CACHE_SHIFT
) {
196 lock_page(obh
->b_page
);
198 * We cannot call radix_tree_preload for the kernels older
199 * than 2.6.23, because it is not exported for modules.
202 err
= radix_tree_preload(GFP_NOFS
& ~__GFP_HIGHMEM
);
205 /* BUG_ON(oldkey != obh->b_page->index); */
206 if (unlikely(oldkey
!= obh
->b_page
->index
))
207 NILFS_PAGE_BUG(obh
->b_page
,
208 "invalid oldkey %lld (newkey=%lld)",
209 (unsigned long long)oldkey
,
210 (unsigned long long)newkey
);
212 spin_lock_irq(&btnc
->tree_lock
);
213 err
= radix_tree_insert(&btnc
->page_tree
, newkey
, obh
->b_page
);
214 spin_unlock_irq(&btnc
->tree_lock
);
216 * Note: page->index will not change to newkey until
217 * nilfs_btnode_commit_change_key() will be called.
218 * To protect the page in intermediate state, the page lock
221 radix_tree_preload_end();
224 else if (err
!= -EEXIST
)
227 err
= invalidate_inode_pages2_range(btnc
, newkey
, newkey
);
230 /* fallback to copy mode */
231 unlock_page(obh
->b_page
);
234 nbh
= nilfs_btnode_create_block(btnc
, newkey
);
243 unlock_page(obh
->b_page
);
248 * nilfs_btnode_commit_change_key
249 * commit the change_key operation prepared by prepare_change_key().
251 void nilfs_btnode_commit_change_key(struct address_space
*btnc
,
252 struct nilfs_btnode_chkey_ctxt
*ctxt
)
254 struct buffer_head
*obh
= ctxt
->bh
, *nbh
= ctxt
->newbh
;
255 __u64 oldkey
= ctxt
->oldkey
, newkey
= ctxt
->newkey
;
258 if (oldkey
== newkey
)
261 if (nbh
== NULL
) { /* blocksize == pagesize */
263 if (unlikely(oldkey
!= opage
->index
))
264 NILFS_PAGE_BUG(opage
,
265 "invalid oldkey %lld (newkey=%lld)",
266 (unsigned long long)oldkey
,
267 (unsigned long long)newkey
);
268 nilfs_btnode_mark_dirty(obh
);
270 spin_lock_irq(&btnc
->tree_lock
);
271 radix_tree_delete(&btnc
->page_tree
, oldkey
);
272 radix_tree_tag_set(&btnc
->page_tree
, newkey
,
273 PAGECACHE_TAG_DIRTY
);
274 spin_unlock_irq(&btnc
->tree_lock
);
276 opage
->index
= obh
->b_blocknr
= newkey
;
279 nilfs_copy_buffer(nbh
, obh
);
280 nilfs_btnode_mark_dirty(nbh
);
282 nbh
->b_blocknr
= newkey
;
284 nilfs_btnode_delete(obh
); /* will decrement bh->b_count */
289 * nilfs_btnode_abort_change_key
290 * abort the change_key operation prepared by prepare_change_key().
292 void nilfs_btnode_abort_change_key(struct address_space
*btnc
,
293 struct nilfs_btnode_chkey_ctxt
*ctxt
)
295 struct buffer_head
*nbh
= ctxt
->newbh
;
296 __u64 oldkey
= ctxt
->oldkey
, newkey
= ctxt
->newkey
;
298 if (oldkey
== newkey
)
301 if (nbh
== NULL
) { /* blocksize == pagesize */
302 spin_lock_irq(&btnc
->tree_lock
);
303 radix_tree_delete(&btnc
->page_tree
, newkey
);
304 spin_unlock_irq(&btnc
->tree_lock
);
305 unlock_page(ctxt
->bh
->b_page
);
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