1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Copyright 1999 Hans Reiser, see reiserfs/README for licensing and copyright
4 * details
5 */
6
7 #include <linux/time.h>
8 #include <linux/pagemap.h>
9 #include <linux/buffer_head.h>
10 #include "reiserfs.h"
11
12 /*
13 * access to tail : when one is going to read tail it must make sure, that is
14 * not running. direct2indirect and indirect2direct can not run concurrently
15 */
16
17 /*
18 * Converts direct items to an unformatted node. Panics if file has no
19 * tail. -ENOSPC if no disk space for conversion
20 */
21 /*
22 * path points to first direct item of the file regardless of how many of
23 * them are there
24 */
direct2indirect(struct reiserfs_transaction_handle * th,struct inode * inode,struct treepath * path,struct buffer_head * unbh,loff_t tail_offset)25 int direct2indirect(struct reiserfs_transaction_handle *th, struct inode *inode,
26 struct treepath *path, struct buffer_head *unbh,
27 loff_t tail_offset)
28 {
29 struct super_block *sb = inode->i_sb;
30 struct buffer_head *up_to_date_bh;
31 struct item_head *p_le_ih = tp_item_head(path);
32 unsigned long total_tail = 0;
33
34 /* Key to search for the last byte of the converted item. */
35 struct cpu_key end_key;
36
37 /*
38 * new indirect item to be inserted or key
39 * of unfm pointer to be pasted
40 */
41 struct item_head ind_ih;
42 int blk_size;
43 /* returned value for reiserfs_insert_item and clones */
44 int retval;
45 /* Handle on an unformatted node that will be inserted in the tree. */
46 unp_t unfm_ptr;
47
48 BUG_ON(!th->t_trans_id);
49
50 REISERFS_SB(sb)->s_direct2indirect++;
51
52 blk_size = sb->s_blocksize;
53
54 /*
55 * and key to search for append or insert pointer to the new
56 * unformatted node.
57 */
58 copy_item_head(&ind_ih, p_le_ih);
59 set_le_ih_k_offset(&ind_ih, tail_offset);
60 set_le_ih_k_type(&ind_ih, TYPE_INDIRECT);
61
62 /* Set the key to search for the place for new unfm pointer */
63 make_cpu_key(&end_key, inode, tail_offset, TYPE_INDIRECT, 4);
64
65 /* FIXME: we could avoid this */
66 if (search_for_position_by_key(sb, &end_key, path) == POSITION_FOUND) {
67 reiserfs_error(sb, "PAP-14030",
68 "pasted or inserted byte exists in "
69 "the tree %K. Use fsck to repair.", &end_key);
70 pathrelse(path);
71 return -EIO;
72 }
73
74 p_le_ih = tp_item_head(path);
75
76 unfm_ptr = cpu_to_le32(unbh->b_blocknr);
77
78 if (is_statdata_le_ih(p_le_ih)) {
79 /* Insert new indirect item. */
80 set_ih_free_space(&ind_ih, 0); /* delete at nearest future */
81 put_ih_item_len(&ind_ih, UNFM_P_SIZE);
82 PATH_LAST_POSITION(path)++;
83 retval =
84 reiserfs_insert_item(th, path, &end_key, &ind_ih, inode,
85 (char *)&unfm_ptr);
86 } else {
87 /* Paste into last indirect item of an object. */
88 retval = reiserfs_paste_into_item(th, path, &end_key, inode,
89 (char *)&unfm_ptr,
90 UNFM_P_SIZE);
91 }
92 if (retval) {
93 return retval;
94 }
95 /*
96 * note: from here there are two keys which have matching first
97 * three key components. They only differ by the fourth one.
98 */
99
100 /* Set the key to search for the direct items of the file */
101 make_cpu_key(&end_key, inode, max_reiserfs_offset(inode), TYPE_DIRECT,
102 4);
103
104 /*
105 * Move bytes from the direct items to the new unformatted node
106 * and delete them.
107 */
108 while (1) {
109 int tail_size;
110
111 /*
112 * end_key.k_offset is set so, that we will always have found
113 * last item of the file
114 */
115 if (search_for_position_by_key(sb, &end_key, path) ==
116 POSITION_FOUND)
117 reiserfs_panic(sb, "PAP-14050",
118 "direct item (%K) not found", &end_key);
119 p_le_ih = tp_item_head(path);
120 RFALSE(!is_direct_le_ih(p_le_ih),
121 "vs-14055: direct item expected(%K), found %h",
122 &end_key, p_le_ih);
123 tail_size = (le_ih_k_offset(p_le_ih) & (blk_size - 1))
124 + ih_item_len(p_le_ih) - 1;
125
126 /*
127 * we only send the unbh pointer if the buffer is not
128 * up to date. this avoids overwriting good data from
129 * writepage() with old data from the disk or buffer cache
130 * Special case: unbh->b_page will be NULL if we are coming
131 * through DIRECT_IO handler here.
132 */
133 if (!unbh->b_page || buffer_uptodate(unbh)
134 || PageUptodate(unbh->b_page)) {
135 up_to_date_bh = NULL;
136 } else {
137 up_to_date_bh = unbh;
138 }
139 retval = reiserfs_delete_item(th, path, &end_key, inode,
140 up_to_date_bh);
141
142 total_tail += retval;
143
144 /* done: file does not have direct items anymore */
145 if (tail_size == retval)
146 break;
147
148 }
149 /*
150 * if we've copied bytes from disk into the page, we need to zero
151 * out the unused part of the block (it was not up to date before)
152 */
153 if (up_to_date_bh) {
154 unsigned pgoff =
155 (tail_offset + total_tail - 1) & (PAGE_SIZE - 1);
156 char *kaddr = kmap_atomic(up_to_date_bh->b_page);
157 memset(kaddr + pgoff, 0, blk_size - total_tail);
158 kunmap_atomic(kaddr);
159 }
160
161 REISERFS_I(inode)->i_first_direct_byte = U32_MAX;
162
163 return 0;
164 }
165
166 /* stolen from fs/buffer.c */
reiserfs_unmap_buffer(struct buffer_head * bh)167 void reiserfs_unmap_buffer(struct buffer_head *bh)
168 {
169 lock_buffer(bh);
170 if (buffer_journaled(bh) || buffer_journal_dirty(bh)) {
171 BUG();
172 }
173 clear_buffer_dirty(bh);
174 /*
175 * Remove the buffer from whatever list it belongs to. We are mostly
176 * interested in removing it from per-sb j_dirty_buffers list, to avoid
177 * BUG() on attempt to write not mapped buffer
178 */
179 if ((!list_empty(&bh->b_assoc_buffers) || bh->b_private) && bh->b_page) {
180 struct inode *inode = bh->b_page->mapping->host;
181 struct reiserfs_journal *j = SB_JOURNAL(inode->i_sb);
182 spin_lock(&j->j_dirty_buffers_lock);
183 list_del_init(&bh->b_assoc_buffers);
184 reiserfs_free_jh(bh);
185 spin_unlock(&j->j_dirty_buffers_lock);
186 }
187 clear_buffer_mapped(bh);
188 clear_buffer_req(bh);
189 clear_buffer_new(bh);
190 bh->b_bdev = NULL;
191 unlock_buffer(bh);
192 }
193
194 /*
195 * this first locks inode (neither reads nor sync are permitted),
196 * reads tail through page cache, insert direct item. When direct item
197 * inserted successfully inode is left locked. Return value is always
198 * what we expect from it (number of cut bytes). But when tail remains
199 * in the unformatted node, we set mode to SKIP_BALANCING and unlock
200 * inode
201 */
indirect2direct(struct reiserfs_transaction_handle * th,struct inode * inode,struct page * page,struct treepath * path,const struct cpu_key * item_key,loff_t n_new_file_size,char * mode)202 int indirect2direct(struct reiserfs_transaction_handle *th,
203 struct inode *inode, struct page *page,
204 struct treepath *path, /* path to the indirect item. */
205 const struct cpu_key *item_key, /* Key to look for
206 * unformatted node
207 * pointer to be cut. */
208 loff_t n_new_file_size, /* New file size. */
209 char *mode)
210 {
211 struct super_block *sb = inode->i_sb;
212 struct item_head s_ih;
213 unsigned long block_size = sb->s_blocksize;
214 char *tail;
215 int tail_len, round_tail_len;
216 loff_t pos, pos1; /* position of first byte of the tail */
217 struct cpu_key key;
218
219 BUG_ON(!th->t_trans_id);
220
221 REISERFS_SB(sb)->s_indirect2direct++;
222
223 *mode = M_SKIP_BALANCING;
224
225 /* store item head path points to. */
226 copy_item_head(&s_ih, tp_item_head(path));
227
228 tail_len = (n_new_file_size & (block_size - 1));
229 if (get_inode_sd_version(inode) == STAT_DATA_V2)
230 round_tail_len = ROUND_UP(tail_len);
231 else
232 round_tail_len = tail_len;
233
234 pos =
235 le_ih_k_offset(&s_ih) - 1 + (ih_item_len(&s_ih) / UNFM_P_SIZE -
236 1) * sb->s_blocksize;
237 pos1 = pos;
238
239 /*
240 * we are protected by i_mutex. The tail can not disapper, not
241 * append can be done either
242 * we are in truncate or packing tail in file_release
243 */
244
245 tail = (char *)kmap(page); /* this can schedule */
246
247 if (path_changed(&s_ih, path)) {
248 /* re-search indirect item */
249 if (search_for_position_by_key(sb, item_key, path)
250 == POSITION_NOT_FOUND)
251 reiserfs_panic(sb, "PAP-5520",
252 "item to be converted %K does not exist",
253 item_key);
254 copy_item_head(&s_ih, tp_item_head(path));
255 #ifdef CONFIG_REISERFS_CHECK
256 pos = le_ih_k_offset(&s_ih) - 1 +
257 (ih_item_len(&s_ih) / UNFM_P_SIZE -
258 1) * sb->s_blocksize;
259 if (pos != pos1)
260 reiserfs_panic(sb, "vs-5530", "tail position "
261 "changed while we were reading it");
262 #endif
263 }
264
265 /* Set direct item header to insert. */
266 make_le_item_head(&s_ih, NULL, get_inode_item_key_version(inode),
267 pos1 + 1, TYPE_DIRECT, round_tail_len,
268 0xffff /*ih_free_space */ );
269
270 /*
271 * we want a pointer to the first byte of the tail in the page.
272 * the page was locked and this part of the page was up to date when
273 * indirect2direct was called, so we know the bytes are still valid
274 */
275 tail = tail + (pos & (PAGE_SIZE - 1));
276
277 PATH_LAST_POSITION(path)++;
278
279 key = *item_key;
280 set_cpu_key_k_type(&key, TYPE_DIRECT);
281 key.key_length = 4;
282 /* Insert tail as new direct item in the tree */
283 if (reiserfs_insert_item(th, path, &key, &s_ih, inode,
284 tail ? tail : NULL) < 0) {
285 /*
286 * No disk memory. So we can not convert last unformatted node
287 * to the direct item. In this case we used to adjust
288 * indirect items's ih_free_space. Now ih_free_space is not
289 * used, it would be ideal to write zeros to corresponding
290 * unformatted node. For now i_size is considered as guard for
291 * going out of file size
292 */
293 kunmap(page);
294 return block_size - round_tail_len;
295 }
296 kunmap(page);
297
298 /* make sure to get the i_blocks changes from reiserfs_insert_item */
299 reiserfs_update_sd(th, inode);
300
301 /*
302 * note: we have now the same as in above direct2indirect
303 * conversion: there are two keys which have matching first three
304 * key components. They only differ by the fourth one.
305 */
306
307 /*
308 * We have inserted new direct item and must remove last
309 * unformatted node.
310 */
311 *mode = M_CUT;
312
313 /* we store position of first direct item in the in-core inode */
314 /* mark_file_with_tail (inode, pos1 + 1); */
315 REISERFS_I(inode)->i_first_direct_byte = pos1 + 1;
316
317 return block_size - round_tail_len;
318 }
319