GNU Linux-libre 5.19-rc6-gnu
[releases.git] / fs / nilfs2 / btnode.c
1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * 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
24 /**
25  * nilfs_init_btnc_inode - initialize B-tree node cache inode
26  * @btnc_inode: inode to be initialized
27  *
28  * nilfs_init_btnc_inode() sets up an inode for B-tree node cache.
29  */
30 void nilfs_init_btnc_inode(struct inode *btnc_inode)
31 {
32         struct nilfs_inode_info *ii = NILFS_I(btnc_inode);
33
34         btnc_inode->i_mode = S_IFREG;
35         ii->i_flags = 0;
36         memset(&ii->i_bmap_data, 0, sizeof(struct nilfs_bmap));
37         mapping_set_gfp_mask(btnc_inode->i_mapping, GFP_NOFS);
38 }
39
40 void nilfs_btnode_cache_clear(struct address_space *btnc)
41 {
42         invalidate_mapping_pages(btnc, 0, -1);
43         truncate_inode_pages(btnc, 0);
44 }
45
46 struct buffer_head *
47 nilfs_btnode_create_block(struct address_space *btnc, __u64 blocknr)
48 {
49         struct inode *inode = btnc->host;
50         struct buffer_head *bh;
51
52         bh = nilfs_grab_buffer(inode, btnc, blocknr, BIT(BH_NILFS_Node));
53         if (unlikely(!bh))
54                 return NULL;
55
56         if (unlikely(buffer_mapped(bh) || buffer_uptodate(bh) ||
57                      buffer_dirty(bh))) {
58                 brelse(bh);
59                 BUG();
60         }
61         memset(bh->b_data, 0, i_blocksize(inode));
62         bh->b_bdev = inode->i_sb->s_bdev;
63         bh->b_blocknr = blocknr;
64         set_buffer_mapped(bh);
65         set_buffer_uptodate(bh);
66
67         unlock_page(bh->b_page);
68         put_page(bh->b_page);
69         return bh;
70 }
71
72 int nilfs_btnode_submit_block(struct address_space *btnc, __u64 blocknr,
73                               sector_t pblocknr, int mode, int mode_flags,
74                               struct buffer_head **pbh, sector_t *submit_ptr)
75 {
76         struct buffer_head *bh;
77         struct inode *inode = btnc->host;
78         struct page *page;
79         int err;
80
81         bh = nilfs_grab_buffer(inode, btnc, blocknr, BIT(BH_NILFS_Node));
82         if (unlikely(!bh))
83                 return -ENOMEM;
84
85         err = -EEXIST; /* internal code */
86         page = bh->b_page;
87
88         if (buffer_uptodate(bh) || buffer_dirty(bh))
89                 goto found;
90
91         if (pblocknr == 0) {
92                 pblocknr = blocknr;
93                 if (inode->i_ino != NILFS_DAT_INO) {
94                         struct the_nilfs *nilfs = inode->i_sb->s_fs_info;
95
96                         /* blocknr is a virtual block number */
97                         err = nilfs_dat_translate(nilfs->ns_dat, blocknr,
98                                                   &pblocknr);
99                         if (unlikely(err)) {
100                                 brelse(bh);
101                                 goto out_locked;
102                         }
103                 }
104         }
105
106         if (mode_flags & REQ_RAHEAD) {
107                 if (pblocknr != *submit_ptr + 1 || !trylock_buffer(bh)) {
108                         err = -EBUSY; /* internal code */
109                         brelse(bh);
110                         goto out_locked;
111                 }
112         } else { /* mode == READ */
113                 lock_buffer(bh);
114         }
115         if (buffer_uptodate(bh)) {
116                 unlock_buffer(bh);
117                 err = -EEXIST; /* internal code */
118                 goto found;
119         }
120         set_buffer_mapped(bh);
121         bh->b_bdev = inode->i_sb->s_bdev;
122         bh->b_blocknr = pblocknr; /* set block address for read */
123         bh->b_end_io = end_buffer_read_sync;
124         get_bh(bh);
125         submit_bh(mode, mode_flags, bh);
126         bh->b_blocknr = blocknr; /* set back to the given block address */
127         *submit_ptr = pblocknr;
128         err = 0;
129 found:
130         *pbh = bh;
131
132 out_locked:
133         unlock_page(page);
134         put_page(page);
135         return err;
136 }
137
138 /**
139  * nilfs_btnode_delete - delete B-tree node buffer
140  * @bh: buffer to be deleted
141  *
142  * nilfs_btnode_delete() invalidates the specified buffer and delete the page
143  * including the buffer if the page gets unbusy.
144  */
145 void nilfs_btnode_delete(struct buffer_head *bh)
146 {
147         struct address_space *mapping;
148         struct page *page = bh->b_page;
149         pgoff_t index = page_index(page);
150         int still_dirty;
151
152         get_page(page);
153         lock_page(page);
154         wait_on_page_writeback(page);
155
156         nilfs_forget_buffer(bh);
157         still_dirty = PageDirty(page);
158         mapping = page->mapping;
159         unlock_page(page);
160         put_page(page);
161
162         if (!still_dirty && mapping)
163                 invalidate_inode_pages2_range(mapping, index, index);
164 }
165
166 /**
167  * nilfs_btnode_prepare_change_key
168  *  prepare to move contents of the block for old key to one of new key.
169  *  the old buffer will not be removed, but might be reused for new buffer.
170  *  it might return -ENOMEM because of memory allocation errors,
171  *  and might return -EIO because of disk read errors.
172  */
173 int nilfs_btnode_prepare_change_key(struct address_space *btnc,
174                                     struct nilfs_btnode_chkey_ctxt *ctxt)
175 {
176         struct buffer_head *obh, *nbh;
177         struct inode *inode = btnc->host;
178         __u64 oldkey = ctxt->oldkey, newkey = ctxt->newkey;
179         int err;
180
181         if (oldkey == newkey)
182                 return 0;
183
184         obh = ctxt->bh;
185         ctxt->newbh = NULL;
186
187         if (inode->i_blkbits == PAGE_SHIFT) {
188                 struct page *opage = obh->b_page;
189                 lock_page(opage);
190 retry:
191                 /* BUG_ON(oldkey != obh->b_page->index); */
192                 if (unlikely(oldkey != opage->index))
193                         NILFS_PAGE_BUG(opage,
194                                        "invalid oldkey %lld (newkey=%lld)",
195                                        (unsigned long long)oldkey,
196                                        (unsigned long long)newkey);
197
198                 xa_lock_irq(&btnc->i_pages);
199                 err = __xa_insert(&btnc->i_pages, newkey, opage, GFP_NOFS);
200                 xa_unlock_irq(&btnc->i_pages);
201                 /*
202                  * Note: page->index will not change to newkey until
203                  * nilfs_btnode_commit_change_key() will be called.
204                  * To protect the page in intermediate state, the page lock
205                  * is held.
206                  */
207                 if (!err)
208                         return 0;
209                 else if (err != -EBUSY)
210                         goto failed_unlock;
211
212                 err = invalidate_inode_pages2_range(btnc, newkey, newkey);
213                 if (!err)
214                         goto retry;
215                 /* fallback to copy mode */
216                 unlock_page(opage);
217         }
218
219         nbh = nilfs_btnode_create_block(btnc, newkey);
220         if (!nbh)
221                 return -ENOMEM;
222
223         BUG_ON(nbh == obh);
224         ctxt->newbh = nbh;
225         return 0;
226
227  failed_unlock:
228         unlock_page(obh->b_page);
229         return err;
230 }
231
232 /**
233  * nilfs_btnode_commit_change_key
234  *  commit the change_key operation prepared by prepare_change_key().
235  */
236 void nilfs_btnode_commit_change_key(struct address_space *btnc,
237                                     struct nilfs_btnode_chkey_ctxt *ctxt)
238 {
239         struct buffer_head *obh = ctxt->bh, *nbh = ctxt->newbh;
240         __u64 oldkey = ctxt->oldkey, newkey = ctxt->newkey;
241         struct page *opage;
242
243         if (oldkey == newkey)
244                 return;
245
246         if (nbh == NULL) {      /* blocksize == pagesize */
247                 opage = obh->b_page;
248                 if (unlikely(oldkey != opage->index))
249                         NILFS_PAGE_BUG(opage,
250                                        "invalid oldkey %lld (newkey=%lld)",
251                                        (unsigned long long)oldkey,
252                                        (unsigned long long)newkey);
253                 mark_buffer_dirty(obh);
254
255                 xa_lock_irq(&btnc->i_pages);
256                 __xa_erase(&btnc->i_pages, oldkey);
257                 __xa_set_mark(&btnc->i_pages, newkey, PAGECACHE_TAG_DIRTY);
258                 xa_unlock_irq(&btnc->i_pages);
259
260                 opage->index = obh->b_blocknr = newkey;
261                 unlock_page(opage);
262         } else {
263                 nilfs_copy_buffer(nbh, obh);
264                 mark_buffer_dirty(nbh);
265
266                 nbh->b_blocknr = newkey;
267                 ctxt->bh = nbh;
268                 nilfs_btnode_delete(obh); /* will decrement bh->b_count */
269         }
270 }
271
272 /**
273  * nilfs_btnode_abort_change_key
274  *  abort the change_key operation prepared by prepare_change_key().
275  */
276 void nilfs_btnode_abort_change_key(struct address_space *btnc,
277                                    struct nilfs_btnode_chkey_ctxt *ctxt)
278 {
279         struct buffer_head *nbh = ctxt->newbh;
280         __u64 oldkey = ctxt->oldkey, newkey = ctxt->newkey;
281
282         if (oldkey == newkey)
283                 return;
284
285         if (nbh == NULL) {      /* blocksize == pagesize */
286                 xa_erase_irq(&btnc->i_pages, newkey);
287                 unlock_page(ctxt->bh->b_page);
288         } else
289                 brelse(nbh);
290 }