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>
37 void nilfs_btnode_cache_init_once(struct address_space *btnc)
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);
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);
49 static struct address_space_operations def_btnode_aops;
51 void nilfs_btnode_cache_init(struct address_space *btnc,
52 struct backing_dev_info *bdi)
54 btnc->host = NULL; /* can safely set to host inode ? */
56 mapping_set_gfp_mask(btnc, GFP_NOFS);
57 btnc->assoc_mapping = NULL;
58 btnc->backing_dev_info = bdi;
59 btnc->a_ops = &def_btnode_aops;
62 void nilfs_btnode_cache_clear(struct address_space *btnc)
64 invalidate_mapping_pages(btnc, 0, -1);
65 truncate_inode_pages(btnc, 0);
68 int nilfs_btnode_submit_block(struct address_space *btnc, __u64 blocknr,
69 sector_t pblocknr, struct buffer_head **pbh,
72 struct buffer_head *bh;
73 struct inode *inode = NILFS_BTNC_I(btnc);
76 bh = nilfs_grab_buffer(inode, btnc, blocknr, 1 << BH_NILFS_Node);
80 err = -EEXIST; /* internal code */
82 if (unlikely(buffer_mapped(bh) || buffer_uptodate(bh) ||
87 bh->b_bdev = NILFS_I_NILFS(inode)->ns_bdev;
88 bh->b_blocknr = blocknr;
89 set_buffer_mapped(bh);
90 set_buffer_uptodate(bh);
94 if (buffer_uptodate(bh) || buffer_dirty(bh))
99 if (inode->i_ino != NILFS_DAT_INO) {
101 nilfs_dat_inode(NILFS_I_NILFS(inode));
103 /* blocknr is a virtual block number */
104 err = nilfs_dat_translate(dat, blocknr, &pblocknr);
112 if (buffer_uptodate(bh)) {
114 err = -EEXIST; /* internal code */
117 set_buffer_mapped(bh);
118 bh->b_bdev = NILFS_I_NILFS(inode)->ns_bdev;
119 bh->b_blocknr = pblocknr; /* set block address for read */
120 bh->b_end_io = end_buffer_read_sync;
123 bh->b_blocknr = blocknr; /* set back to the given block address */
129 unlock_page(bh->b_page);
130 page_cache_release(bh->b_page);
134 int nilfs_btnode_get(struct address_space *btnc, __u64 blocknr,
135 sector_t pblocknr, struct buffer_head **pbh, int newblk)
137 struct buffer_head *bh;
140 err = nilfs_btnode_submit_block(btnc, blocknr, pblocknr, pbh, newblk);
141 if (err == -EEXIST) /* internal code (cache hit) */
148 if (!buffer_uptodate(bh)) {
156 * nilfs_btnode_delete - delete B-tree node buffer
157 * @bh: buffer to be deleted
159 * nilfs_btnode_delete() invalidates the specified buffer and delete the page
160 * including the buffer if the page gets unbusy.
162 void nilfs_btnode_delete(struct buffer_head *bh)
164 struct address_space *mapping;
165 struct page *page = bh->b_page;
166 pgoff_t index = page_index(page);
169 page_cache_get(page);
171 wait_on_page_writeback(page);
173 nilfs_forget_buffer(bh);
174 still_dirty = PageDirty(page);
175 mapping = page->mapping;
177 page_cache_release(page);
179 if (!still_dirty && mapping)
180 invalidate_inode_pages2_range(mapping, index, index);
184 * nilfs_btnode_prepare_change_key
185 * prepare to move contents of the block for old key to one of new key.
186 * the old buffer will not be removed, but might be reused for new buffer.
187 * it might return -ENOMEM because of memory allocation errors,
188 * and might return -EIO because of disk read errors.
190 int nilfs_btnode_prepare_change_key(struct address_space *btnc,
191 struct nilfs_btnode_chkey_ctxt *ctxt)
193 struct buffer_head *obh, *nbh;
194 struct inode *inode = NILFS_BTNC_I(btnc);
195 __u64 oldkey = ctxt->oldkey, newkey = ctxt->newkey;
198 if (oldkey == newkey)
204 if (inode->i_blkbits == PAGE_CACHE_SHIFT) {
205 lock_page(obh->b_page);
207 * We cannot call radix_tree_preload for the kernels older
208 * than 2.6.23, because it is not exported for modules.
210 err = radix_tree_preload(GFP_NOFS & ~__GFP_HIGHMEM);
213 /* BUG_ON(oldkey != obh->b_page->index); */
214 if (unlikely(oldkey != obh->b_page->index))
215 NILFS_PAGE_BUG(obh->b_page,
216 "invalid oldkey %lld (newkey=%lld)",
217 (unsigned long long)oldkey,
218 (unsigned long long)newkey);
221 spin_lock_irq(&btnc->tree_lock);
222 err = radix_tree_insert(&btnc->page_tree, newkey, obh->b_page);
223 spin_unlock_irq(&btnc->tree_lock);
225 * Note: page->index will not change to newkey until
226 * nilfs_btnode_commit_change_key() will be called.
227 * To protect the page in intermediate state, the page lock
230 radix_tree_preload_end();
233 else if (err != -EEXIST)
236 err = invalidate_inode_pages2_range(btnc, newkey, newkey);
239 /* fallback to copy mode */
240 unlock_page(obh->b_page);
243 err = nilfs_btnode_get(btnc, newkey, 0, &nbh, 1);
251 unlock_page(obh->b_page);
256 * nilfs_btnode_commit_change_key
257 * commit the change_key operation prepared by prepare_change_key().
259 void nilfs_btnode_commit_change_key(struct address_space *btnc,
260 struct nilfs_btnode_chkey_ctxt *ctxt)
262 struct buffer_head *obh = ctxt->bh, *nbh = ctxt->newbh;
263 __u64 oldkey = ctxt->oldkey, newkey = ctxt->newkey;
266 if (oldkey == newkey)
269 if (nbh == NULL) { /* blocksize == pagesize */
271 if (unlikely(oldkey != opage->index))
272 NILFS_PAGE_BUG(opage,
273 "invalid oldkey %lld (newkey=%lld)",
274 (unsigned long long)oldkey,
275 (unsigned long long)newkey);
276 if (!test_set_buffer_dirty(obh) && TestSetPageDirty(opage))
279 spin_lock_irq(&btnc->tree_lock);
280 radix_tree_delete(&btnc->page_tree, oldkey);
281 radix_tree_tag_set(&btnc->page_tree, newkey,
282 PAGECACHE_TAG_DIRTY);
283 spin_unlock_irq(&btnc->tree_lock);
285 opage->index = obh->b_blocknr = newkey;
288 nilfs_copy_buffer(nbh, obh);
289 nilfs_btnode_mark_dirty(nbh);
291 nbh->b_blocknr = newkey;
293 nilfs_btnode_delete(obh); /* will decrement bh->b_count */
298 * nilfs_btnode_abort_change_key
299 * abort the change_key operation prepared by prepare_change_key().
301 void nilfs_btnode_abort_change_key(struct address_space *btnc,
302 struct nilfs_btnode_chkey_ctxt *ctxt)
304 struct buffer_head *nbh = ctxt->newbh;
305 __u64 oldkey = ctxt->oldkey, newkey = ctxt->newkey;
307 if (oldkey == newkey)
310 if (nbh == NULL) { /* blocksize == pagesize */
311 spin_lock_irq(&btnc->tree_lock);
312 radix_tree_delete(&btnc->page_tree, newkey);
313 spin_unlock_irq(&btnc->tree_lock);
314 unlock_page(ctxt->bh->b_page);