1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * btnode.c - NILFS B-tree node cache
4 *
5 * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
6 *
7 * Originally written by Seiji Kihara.
8 * Fully revised by Ryusuke Konishi for stabilization and simplification.
9 *
10 */
11
12 #include <linux/types.h>
13 #include <linux/buffer_head.h>
14 #include <linux/mm.h>
15 #include <linux/backing-dev.h>
16 #include <linux/gfp.h>
17 #include "nilfs.h"
18 #include "mdt.h"
19 #include "dat.h"
20 #include "page.h"
21 #include "btnode.h"
22
nilfs_btnode_cache_clear(struct address_space * btnc)23 void nilfs_btnode_cache_clear(struct address_space *btnc)
24 {
25 invalidate_mapping_pages(btnc, 0, -1);
26 truncate_inode_pages(btnc, 0);
27 }
28
29 struct buffer_head *
nilfs_btnode_create_block(struct address_space * btnc,__u64 blocknr)30 nilfs_btnode_create_block(struct address_space *btnc, __u64 blocknr)
31 {
32 struct inode *inode = NILFS_BTNC_I(btnc);
33 struct buffer_head *bh;
34
35 bh = nilfs_grab_buffer(inode, btnc, blocknr, BIT(BH_NILFS_Node));
36 if (unlikely(!bh))
37 return NULL;
38
39 if (unlikely(buffer_mapped(bh) || buffer_uptodate(bh) ||
40 buffer_dirty(bh))) {
41 brelse(bh);
42 BUG();
43 }
44 memset(bh->b_data, 0, i_blocksize(inode));
45 bh->b_bdev = inode->i_sb->s_bdev;
46 bh->b_blocknr = blocknr;
47 set_buffer_mapped(bh);
48 set_buffer_uptodate(bh);
49
50 unlock_page(bh->b_page);
51 put_page(bh->b_page);
52 return bh;
53 }
54
nilfs_btnode_submit_block(struct address_space * btnc,__u64 blocknr,sector_t pblocknr,int mode,int mode_flags,struct buffer_head ** pbh,sector_t * submit_ptr)55 int nilfs_btnode_submit_block(struct address_space *btnc, __u64 blocknr,
56 sector_t pblocknr, int mode, int mode_flags,
57 struct buffer_head **pbh, sector_t *submit_ptr)
58 {
59 struct buffer_head *bh;
60 struct inode *inode = NILFS_BTNC_I(btnc);
61 struct page *page;
62 int err;
63
64 bh = nilfs_grab_buffer(inode, btnc, blocknr, BIT(BH_NILFS_Node));
65 if (unlikely(!bh))
66 return -ENOMEM;
67
68 err = -EEXIST; /* internal code */
69 page = bh->b_page;
70
71 if (buffer_uptodate(bh) || buffer_dirty(bh))
72 goto found;
73
74 if (pblocknr == 0) {
75 pblocknr = blocknr;
76 if (inode->i_ino != NILFS_DAT_INO) {
77 struct the_nilfs *nilfs = inode->i_sb->s_fs_info;
78
79 /* blocknr is a virtual block number */
80 err = nilfs_dat_translate(nilfs->ns_dat, blocknr,
81 &pblocknr);
82 if (unlikely(err)) {
83 brelse(bh);
84 goto out_locked;
85 }
86 }
87 }
88
89 if (mode_flags & REQ_RAHEAD) {
90 if (pblocknr != *submit_ptr + 1 || !trylock_buffer(bh)) {
91 err = -EBUSY; /* internal code */
92 brelse(bh);
93 goto out_locked;
94 }
95 } else { /* mode == READ */
96 lock_buffer(bh);
97 }
98 if (buffer_uptodate(bh)) {
99 unlock_buffer(bh);
100 err = -EEXIST; /* internal code */
101 goto found;
102 }
103 set_buffer_mapped(bh);
104 bh->b_bdev = inode->i_sb->s_bdev;
105 bh->b_blocknr = pblocknr; /* set block address for read */
106 bh->b_end_io = end_buffer_read_sync;
107 get_bh(bh);
108 submit_bh(mode, mode_flags, bh);
109 bh->b_blocknr = blocknr; /* set back to the given block address */
110 *submit_ptr = pblocknr;
111 err = 0;
112 found:
113 *pbh = bh;
114
115 out_locked:
116 unlock_page(page);
117 put_page(page);
118 return err;
119 }
120
121 /**
122 * nilfs_btnode_delete - delete B-tree node buffer
123 * @bh: buffer to be deleted
124 *
125 * nilfs_btnode_delete() invalidates the specified buffer and delete the page
126 * including the buffer if the page gets unbusy.
127 */
nilfs_btnode_delete(struct buffer_head * bh)128 void nilfs_btnode_delete(struct buffer_head *bh)
129 {
130 struct address_space *mapping;
131 struct page *page = bh->b_page;
132 pgoff_t index = page_index(page);
133 int still_dirty;
134
135 get_page(page);
136 lock_page(page);
137 wait_on_page_writeback(page);
138
139 nilfs_forget_buffer(bh);
140 still_dirty = PageDirty(page);
141 mapping = page->mapping;
142 unlock_page(page);
143 put_page(page);
144
145 if (!still_dirty && mapping)
146 invalidate_inode_pages2_range(mapping, index, index);
147 }
148
149 /**
150 * nilfs_btnode_prepare_change_key
151 * prepare to move contents of the block for old key to one of new key.
152 * the old buffer will not be removed, but might be reused for new buffer.
153 * it might return -ENOMEM because of memory allocation errors,
154 * and might return -EIO because of disk read errors.
155 */
nilfs_btnode_prepare_change_key(struct address_space * btnc,struct nilfs_btnode_chkey_ctxt * ctxt)156 int nilfs_btnode_prepare_change_key(struct address_space *btnc,
157 struct nilfs_btnode_chkey_ctxt *ctxt)
158 {
159 struct buffer_head *obh, *nbh;
160 struct inode *inode = NILFS_BTNC_I(btnc);
161 __u64 oldkey = ctxt->oldkey, newkey = ctxt->newkey;
162 int err;
163
164 if (oldkey == newkey)
165 return 0;
166
167 obh = ctxt->bh;
168 ctxt->newbh = NULL;
169
170 if (inode->i_blkbits == PAGE_SHIFT) {
171 struct page *opage = obh->b_page;
172 lock_page(opage);
173 retry:
174 /* BUG_ON(oldkey != obh->b_page->index); */
175 if (unlikely(oldkey != opage->index))
176 NILFS_PAGE_BUG(opage,
177 "invalid oldkey %lld (newkey=%lld)",
178 (unsigned long long)oldkey,
179 (unsigned long long)newkey);
180
181 xa_lock_irq(&btnc->i_pages);
182 err = __xa_insert(&btnc->i_pages, newkey, opage, GFP_NOFS);
183 xa_unlock_irq(&btnc->i_pages);
184 /*
185 * Note: page->index will not change to newkey until
186 * nilfs_btnode_commit_change_key() will be called.
187 * To protect the page in intermediate state, the page lock
188 * is held.
189 */
190 if (!err)
191 return 0;
192 else if (err != -EBUSY)
193 goto failed_unlock;
194
195 err = invalidate_inode_pages2_range(btnc, newkey, newkey);
196 if (!err)
197 goto retry;
198 /* fallback to copy mode */
199 unlock_page(opage);
200 }
201
202 nbh = nilfs_btnode_create_block(btnc, newkey);
203 if (!nbh)
204 return -ENOMEM;
205
206 BUG_ON(nbh == obh);
207 ctxt->newbh = nbh;
208 return 0;
209
210 failed_unlock:
211 unlock_page(obh->b_page);
212 return err;
213 }
214
215 /**
216 * nilfs_btnode_commit_change_key
217 * commit the change_key operation prepared by prepare_change_key().
218 */
nilfs_btnode_commit_change_key(struct address_space * btnc,struct nilfs_btnode_chkey_ctxt * ctxt)219 void nilfs_btnode_commit_change_key(struct address_space *btnc,
220 struct nilfs_btnode_chkey_ctxt *ctxt)
221 {
222 struct buffer_head *obh = ctxt->bh, *nbh = ctxt->newbh;
223 __u64 oldkey = ctxt->oldkey, newkey = ctxt->newkey;
224 struct page *opage;
225
226 if (oldkey == newkey)
227 return;
228
229 if (nbh == NULL) { /* blocksize == pagesize */
230 opage = obh->b_page;
231 if (unlikely(oldkey != opage->index))
232 NILFS_PAGE_BUG(opage,
233 "invalid oldkey %lld (newkey=%lld)",
234 (unsigned long long)oldkey,
235 (unsigned long long)newkey);
236 mark_buffer_dirty(obh);
237
238 xa_lock_irq(&btnc->i_pages);
239 __xa_erase(&btnc->i_pages, oldkey);
240 __xa_set_mark(&btnc->i_pages, newkey, PAGECACHE_TAG_DIRTY);
241 xa_unlock_irq(&btnc->i_pages);
242
243 opage->index = obh->b_blocknr = newkey;
244 unlock_page(opage);
245 } else {
246 nilfs_copy_buffer(nbh, obh);
247 mark_buffer_dirty(nbh);
248
249 nbh->b_blocknr = newkey;
250 ctxt->bh = nbh;
251 nilfs_btnode_delete(obh); /* will decrement bh->b_count */
252 }
253 }
254
255 /**
256 * nilfs_btnode_abort_change_key
257 * abort the change_key operation prepared by prepare_change_key().
258 */
nilfs_btnode_abort_change_key(struct address_space * btnc,struct nilfs_btnode_chkey_ctxt * ctxt)259 void nilfs_btnode_abort_change_key(struct address_space *btnc,
260 struct nilfs_btnode_chkey_ctxt *ctxt)
261 {
262 struct buffer_head *nbh = ctxt->newbh;
263 __u64 oldkey = ctxt->oldkey, newkey = ctxt->newkey;
264
265 if (oldkey == newkey)
266 return;
267
268 if (nbh == NULL) { /* blocksize == pagesize */
269 xa_erase_irq(&btnc->i_pages, newkey);
270 unlock_page(ctxt->bh->b_page);
271 } else
272 brelse(nbh);
273 }
274