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>
37 void nilfs_btnode_cache_init(struct address_space *btnc,
38 struct backing_dev_info *bdi)
40 nilfs_mapping_init(btnc, bdi);
43 void nilfs_btnode_cache_clear(struct address_space *btnc)
45 invalidate_mapping_pages(btnc, 0, -1);
46 truncate_inode_pages(btnc, 0);
50 nilfs_btnode_create_block(struct address_space *btnc, __u64 blocknr)
52 struct inode *inode = NILFS_BTNC_I(btnc);
53 struct buffer_head *bh;
55 bh = nilfs_grab_buffer(inode, btnc, blocknr, 1 << BH_NILFS_Node);
59 if (unlikely(buffer_mapped(bh) || buffer_uptodate(bh) ||
64 memset(bh->b_data, 0, 1 << inode->i_blkbits);
65 bh->b_bdev = NILFS_I_NILFS(inode)->ns_bdev;
66 bh->b_blocknr = blocknr;
67 set_buffer_mapped(bh);
68 set_buffer_uptodate(bh);
70 unlock_page(bh->b_page);
71 page_cache_release(bh->b_page);
75 int nilfs_btnode_submit_block(struct address_space *btnc, __u64 blocknr,
76 sector_t pblocknr, int mode,
77 struct buffer_head **pbh, sector_t *submit_ptr)
79 struct buffer_head *bh;
80 struct inode *inode = NILFS_BTNC_I(btnc);
84 bh = nilfs_grab_buffer(inode, btnc, blocknr, 1 << BH_NILFS_Node);
88 err = -EEXIST; /* internal code */
91 if (buffer_uptodate(bh) || buffer_dirty(bh))
96 if (inode->i_ino != NILFS_DAT_INO) {
97 struct inode *dat = NILFS_I_NILFS(inode)->ns_dat;
99 /* blocknr is a virtual block number */
100 err = nilfs_dat_translate(dat, blocknr, &pblocknr);
109 if (pblocknr != *submit_ptr + 1 || !trylock_buffer(bh)) {
110 err = -EBUSY; /* internal code */
114 } else { /* mode == READ */
117 if (buffer_uptodate(bh)) {
119 err = -EEXIST; /* internal code */
122 set_buffer_mapped(bh);
123 bh->b_bdev = NILFS_I_NILFS(inode)->ns_bdev;
124 bh->b_blocknr = pblocknr; /* set block address for read */
125 bh->b_end_io = end_buffer_read_sync;
128 bh->b_blocknr = blocknr; /* set back to the given block address */
129 *submit_ptr = pblocknr;
136 page_cache_release(page);
141 * nilfs_btnode_delete - delete B-tree node buffer
142 * @bh: buffer to be deleted
144 * nilfs_btnode_delete() invalidates the specified buffer and delete the page
145 * including the buffer if the page gets unbusy.
147 void nilfs_btnode_delete(struct buffer_head *bh)
149 struct address_space *mapping;
150 struct page *page = bh->b_page;
151 pgoff_t index = page_index(page);
154 page_cache_get(page);
156 wait_on_page_writeback(page);
158 nilfs_forget_buffer(bh);
159 still_dirty = PageDirty(page);
160 mapping = page->mapping;
162 page_cache_release(page);
164 if (!still_dirty && mapping)
165 invalidate_inode_pages2_range(mapping, index, index);
169 * nilfs_btnode_prepare_change_key
170 * prepare to move contents of the block for old key to one of new key.
171 * the old buffer will not be removed, but might be reused for new buffer.
172 * it might return -ENOMEM because of memory allocation errors,
173 * and might return -EIO because of disk read errors.
175 int nilfs_btnode_prepare_change_key(struct address_space *btnc,
176 struct nilfs_btnode_chkey_ctxt *ctxt)
178 struct buffer_head *obh, *nbh;
179 struct inode *inode = NILFS_BTNC_I(btnc);
180 __u64 oldkey = ctxt->oldkey, newkey = ctxt->newkey;
183 if (oldkey == newkey)
189 if (inode->i_blkbits == PAGE_CACHE_SHIFT) {
190 lock_page(obh->b_page);
192 * We cannot call radix_tree_preload for the kernels older
193 * than 2.6.23, because it is not exported for modules.
196 err = radix_tree_preload(GFP_NOFS & ~__GFP_HIGHMEM);
199 /* BUG_ON(oldkey != obh->b_page->index); */
200 if (unlikely(oldkey != obh->b_page->index))
201 NILFS_PAGE_BUG(obh->b_page,
202 "invalid oldkey %lld (newkey=%lld)",
203 (unsigned long long)oldkey,
204 (unsigned long long)newkey);
206 spin_lock_irq(&btnc->tree_lock);
207 err = radix_tree_insert(&btnc->page_tree, newkey, obh->b_page);
208 spin_unlock_irq(&btnc->tree_lock);
210 * Note: page->index will not change to newkey until
211 * nilfs_btnode_commit_change_key() will be called.
212 * To protect the page in intermediate state, the page lock
215 radix_tree_preload_end();
218 else if (err != -EEXIST)
221 err = invalidate_inode_pages2_range(btnc, newkey, newkey);
224 /* fallback to copy mode */
225 unlock_page(obh->b_page);
228 nbh = nilfs_btnode_create_block(btnc, newkey);
237 unlock_page(obh->b_page);
242 * nilfs_btnode_commit_change_key
243 * commit the change_key operation prepared by prepare_change_key().
245 void nilfs_btnode_commit_change_key(struct address_space *btnc,
246 struct nilfs_btnode_chkey_ctxt *ctxt)
248 struct buffer_head *obh = ctxt->bh, *nbh = ctxt->newbh;
249 __u64 oldkey = ctxt->oldkey, newkey = ctxt->newkey;
252 if (oldkey == newkey)
255 if (nbh == NULL) { /* blocksize == pagesize */
257 if (unlikely(oldkey != opage->index))
258 NILFS_PAGE_BUG(opage,
259 "invalid oldkey %lld (newkey=%lld)",
260 (unsigned long long)oldkey,
261 (unsigned long long)newkey);
262 nilfs_btnode_mark_dirty(obh);
264 spin_lock_irq(&btnc->tree_lock);
265 radix_tree_delete(&btnc->page_tree, oldkey);
266 radix_tree_tag_set(&btnc->page_tree, newkey,
267 PAGECACHE_TAG_DIRTY);
268 spin_unlock_irq(&btnc->tree_lock);
270 opage->index = obh->b_blocknr = newkey;
273 nilfs_copy_buffer(nbh, obh);
274 nilfs_btnode_mark_dirty(nbh);
276 nbh->b_blocknr = newkey;
278 nilfs_btnode_delete(obh); /* will decrement bh->b_count */
283 * nilfs_btnode_abort_change_key
284 * abort the change_key operation prepared by prepare_change_key().
286 void nilfs_btnode_abort_change_key(struct address_space *btnc,
287 struct nilfs_btnode_chkey_ctxt *ctxt)
289 struct buffer_head *nbh = ctxt->newbh;
290 __u64 oldkey = ctxt->oldkey, newkey = ctxt->newkey;
292 if (oldkey == newkey)
295 if (nbh == NULL) { /* blocksize == pagesize */
296 spin_lock_irq(&btnc->tree_lock);
297 radix_tree_delete(&btnc->page_tree, newkey);
298 spin_unlock_irq(&btnc->tree_lock);
299 unlock_page(ctxt->bh->b_page);