GNU Linux-libre 4.19.211-gnu1
[releases.git] / fs / nilfs2 / btnode.c
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
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 *
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
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  */
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  */
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                 lock_page(obh->b_page);
172                 /*
173                  * We cannot call radix_tree_preload for the kernels older
174                  * than 2.6.23, because it is not exported for modules.
175                  */
176 retry:
177                 err = radix_tree_preload(GFP_NOFS & ~__GFP_HIGHMEM);
178                 if (err)
179                         goto failed_unlock;
180                 /* BUG_ON(oldkey != obh->b_page->index); */
181                 if (unlikely(oldkey != obh->b_page->index))
182                         NILFS_PAGE_BUG(obh->b_page,
183                                        "invalid oldkey %lld (newkey=%lld)",
184                                        (unsigned long long)oldkey,
185                                        (unsigned long long)newkey);
186
187                 xa_lock_irq(&btnc->i_pages);
188                 err = radix_tree_insert(&btnc->i_pages, newkey, obh->b_page);
189                 xa_unlock_irq(&btnc->i_pages);
190                 /*
191                  * Note: page->index will not change to newkey until
192                  * nilfs_btnode_commit_change_key() will be called.
193                  * To protect the page in intermediate state, the page lock
194                  * is held.
195                  */
196                 radix_tree_preload_end();
197                 if (!err)
198                         return 0;
199                 else if (err != -EEXIST)
200                         goto failed_unlock;
201
202                 err = invalidate_inode_pages2_range(btnc, newkey, newkey);
203                 if (!err)
204                         goto retry;
205                 /* fallback to copy mode */
206                 unlock_page(obh->b_page);
207         }
208
209         nbh = nilfs_btnode_create_block(btnc, newkey);
210         if (!nbh)
211                 return -ENOMEM;
212
213         BUG_ON(nbh == obh);
214         ctxt->newbh = nbh;
215         return 0;
216
217  failed_unlock:
218         unlock_page(obh->b_page);
219         return err;
220 }
221
222 /**
223  * nilfs_btnode_commit_change_key
224  *  commit the change_key operation prepared by prepare_change_key().
225  */
226 void nilfs_btnode_commit_change_key(struct address_space *btnc,
227                                     struct nilfs_btnode_chkey_ctxt *ctxt)
228 {
229         struct buffer_head *obh = ctxt->bh, *nbh = ctxt->newbh;
230         __u64 oldkey = ctxt->oldkey, newkey = ctxt->newkey;
231         struct page *opage;
232
233         if (oldkey == newkey)
234                 return;
235
236         if (nbh == NULL) {      /* blocksize == pagesize */
237                 opage = obh->b_page;
238                 if (unlikely(oldkey != opage->index))
239                         NILFS_PAGE_BUG(opage,
240                                        "invalid oldkey %lld (newkey=%lld)",
241                                        (unsigned long long)oldkey,
242                                        (unsigned long long)newkey);
243                 mark_buffer_dirty(obh);
244
245                 xa_lock_irq(&btnc->i_pages);
246                 radix_tree_delete(&btnc->i_pages, oldkey);
247                 radix_tree_tag_set(&btnc->i_pages, newkey,
248                                    PAGECACHE_TAG_DIRTY);
249                 xa_unlock_irq(&btnc->i_pages);
250
251                 opage->index = obh->b_blocknr = newkey;
252                 unlock_page(opage);
253         } else {
254                 nilfs_copy_buffer(nbh, obh);
255                 mark_buffer_dirty(nbh);
256
257                 nbh->b_blocknr = newkey;
258                 ctxt->bh = nbh;
259                 nilfs_btnode_delete(obh); /* will decrement bh->b_count */
260         }
261 }
262
263 /**
264  * nilfs_btnode_abort_change_key
265  *  abort the change_key operation prepared by prepare_change_key().
266  */
267 void nilfs_btnode_abort_change_key(struct address_space *btnc,
268                                    struct nilfs_btnode_chkey_ctxt *ctxt)
269 {
270         struct buffer_head *nbh = ctxt->newbh;
271         __u64 oldkey = ctxt->oldkey, newkey = ctxt->newkey;
272
273         if (oldkey == newkey)
274                 return;
275
276         if (nbh == NULL) {      /* blocksize == pagesize */
277                 xa_lock_irq(&btnc->i_pages);
278                 radix_tree_delete(&btnc->i_pages, newkey);
279                 xa_unlock_irq(&btnc->i_pages);
280                 unlock_page(ctxt->bh->b_page);
281         } else
282                 brelse(nbh);
283 }