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 * Originally written by Seiji Kihara.
17 * Fully revised by Ryusuke Konishi for stabilization and simplification.
21 #include <linux/types.h>
22 #include <linux/buffer_head.h>
24 #include <linux/backing-dev.h>
25 #include <linux/gfp.h>
32 void nilfs_btnode_cache_clear(struct address_space
*btnc
)
34 invalidate_mapping_pages(btnc
, 0, -1);
35 truncate_inode_pages(btnc
, 0);
39 nilfs_btnode_create_block(struct address_space
*btnc
, __u64 blocknr
)
41 struct inode
*inode
= NILFS_BTNC_I(btnc
);
42 struct buffer_head
*bh
;
44 bh
= nilfs_grab_buffer(inode
, btnc
, blocknr
, 1 << BH_NILFS_Node
);
48 if (unlikely(buffer_mapped(bh
) || buffer_uptodate(bh
) ||
53 memset(bh
->b_data
, 0, 1 << inode
->i_blkbits
);
54 bh
->b_bdev
= inode
->i_sb
->s_bdev
;
55 bh
->b_blocknr
= blocknr
;
56 set_buffer_mapped(bh
);
57 set_buffer_uptodate(bh
);
59 unlock_page(bh
->b_page
);
64 int nilfs_btnode_submit_block(struct address_space
*btnc
, __u64 blocknr
,
65 sector_t pblocknr
, int mode
,
66 struct buffer_head
**pbh
, sector_t
*submit_ptr
)
68 struct buffer_head
*bh
;
69 struct inode
*inode
= NILFS_BTNC_I(btnc
);
73 bh
= nilfs_grab_buffer(inode
, btnc
, blocknr
, 1 << BH_NILFS_Node
);
77 err
= -EEXIST
; /* internal code */
80 if (buffer_uptodate(bh
) || buffer_dirty(bh
))
85 if (inode
->i_ino
!= NILFS_DAT_INO
) {
86 struct the_nilfs
*nilfs
= inode
->i_sb
->s_fs_info
;
88 /* blocknr is a virtual block number */
89 err
= nilfs_dat_translate(nilfs
->ns_dat
, blocknr
,
99 if (pblocknr
!= *submit_ptr
+ 1 || !trylock_buffer(bh
)) {
100 err
= -EBUSY
; /* internal code */
104 } else { /* mode == READ */
107 if (buffer_uptodate(bh
)) {
109 err
= -EEXIST
; /* internal code */
112 set_buffer_mapped(bh
);
113 bh
->b_bdev
= inode
->i_sb
->s_bdev
;
114 bh
->b_blocknr
= pblocknr
; /* set block address for read */
115 bh
->b_end_io
= end_buffer_read_sync
;
118 bh
->b_blocknr
= blocknr
; /* set back to the given block address */
119 *submit_ptr
= pblocknr
;
131 * nilfs_btnode_delete - delete B-tree node buffer
132 * @bh: buffer to be deleted
134 * nilfs_btnode_delete() invalidates the specified buffer and delete the page
135 * including the buffer if the page gets unbusy.
137 void nilfs_btnode_delete(struct buffer_head
*bh
)
139 struct address_space
*mapping
;
140 struct page
*page
= bh
->b_page
;
141 pgoff_t index
= page_index(page
);
146 wait_on_page_writeback(page
);
148 nilfs_forget_buffer(bh
);
149 still_dirty
= PageDirty(page
);
150 mapping
= page
->mapping
;
154 if (!still_dirty
&& mapping
)
155 invalidate_inode_pages2_range(mapping
, index
, index
);
159 * nilfs_btnode_prepare_change_key
160 * prepare to move contents of the block for old key to one of new key.
161 * the old buffer will not be removed, but might be reused for new buffer.
162 * it might return -ENOMEM because of memory allocation errors,
163 * and might return -EIO because of disk read errors.
165 int nilfs_btnode_prepare_change_key(struct address_space
*btnc
,
166 struct nilfs_btnode_chkey_ctxt
*ctxt
)
168 struct buffer_head
*obh
, *nbh
;
169 struct inode
*inode
= NILFS_BTNC_I(btnc
);
170 __u64 oldkey
= ctxt
->oldkey
, newkey
= ctxt
->newkey
;
173 if (oldkey
== newkey
)
179 if (inode
->i_blkbits
== PAGE_SHIFT
) {
180 lock_page(obh
->b_page
);
182 * We cannot call radix_tree_preload for the kernels older
183 * than 2.6.23, because it is not exported for modules.
186 err
= radix_tree_preload(GFP_NOFS
& ~__GFP_HIGHMEM
);
189 /* BUG_ON(oldkey != obh->b_page->index); */
190 if (unlikely(oldkey
!= obh
->b_page
->index
))
191 NILFS_PAGE_BUG(obh
->b_page
,
192 "invalid oldkey %lld (newkey=%lld)",
193 (unsigned long long)oldkey
,
194 (unsigned long long)newkey
);
196 spin_lock_irq(&btnc
->tree_lock
);
197 err
= radix_tree_insert(&btnc
->page_tree
, newkey
, obh
->b_page
);
198 spin_unlock_irq(&btnc
->tree_lock
);
200 * Note: page->index will not change to newkey until
201 * nilfs_btnode_commit_change_key() will be called.
202 * To protect the page in intermediate state, the page lock
205 radix_tree_preload_end();
208 else if (err
!= -EEXIST
)
211 err
= invalidate_inode_pages2_range(btnc
, newkey
, newkey
);
214 /* fallback to copy mode */
215 unlock_page(obh
->b_page
);
218 nbh
= nilfs_btnode_create_block(btnc
, newkey
);
227 unlock_page(obh
->b_page
);
232 * nilfs_btnode_commit_change_key
233 * commit the change_key operation prepared by prepare_change_key().
235 void nilfs_btnode_commit_change_key(struct address_space
*btnc
,
236 struct nilfs_btnode_chkey_ctxt
*ctxt
)
238 struct buffer_head
*obh
= ctxt
->bh
, *nbh
= ctxt
->newbh
;
239 __u64 oldkey
= ctxt
->oldkey
, newkey
= ctxt
->newkey
;
242 if (oldkey
== newkey
)
245 if (nbh
== NULL
) { /* blocksize == pagesize */
247 if (unlikely(oldkey
!= opage
->index
))
248 NILFS_PAGE_BUG(opage
,
249 "invalid oldkey %lld (newkey=%lld)",
250 (unsigned long long)oldkey
,
251 (unsigned long long)newkey
);
252 mark_buffer_dirty(obh
);
254 spin_lock_irq(&btnc
->tree_lock
);
255 radix_tree_delete(&btnc
->page_tree
, oldkey
);
256 radix_tree_tag_set(&btnc
->page_tree
, newkey
,
257 PAGECACHE_TAG_DIRTY
);
258 spin_unlock_irq(&btnc
->tree_lock
);
260 opage
->index
= obh
->b_blocknr
= newkey
;
263 nilfs_copy_buffer(nbh
, obh
);
264 mark_buffer_dirty(nbh
);
266 nbh
->b_blocknr
= newkey
;
268 nilfs_btnode_delete(obh
); /* will decrement bh->b_count */
273 * nilfs_btnode_abort_change_key
274 * abort the change_key operation prepared by prepare_change_key().
276 void nilfs_btnode_abort_change_key(struct address_space
*btnc
,
277 struct nilfs_btnode_chkey_ctxt
*ctxt
)
279 struct buffer_head
*nbh
= ctxt
->newbh
;
280 __u64 oldkey
= ctxt
->oldkey
, newkey
= ctxt
->newkey
;
282 if (oldkey
== newkey
)
285 if (nbh
== NULL
) { /* blocksize == pagesize */
286 spin_lock_irq(&btnc
->tree_lock
);
287 radix_tree_delete(&btnc
->page_tree
, newkey
);
288 spin_unlock_irq(&btnc
->tree_lock
);
289 unlock_page(ctxt
->bh
->b_page
);
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