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