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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 <linux/reiserfs_fs.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 */ | |
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, KM_USER0); | |
132 | memset(kaddr + pgoff, 0, blk_size - total_tail); | |
133 | kunmap_atomic(kaddr, KM_USER0); | |
134 | } | |
135 | ||
136 | REISERFS_I(inode)->i_first_direct_byte = U32_MAX; | |
137 | ||
138 | return 0; | |
139 | } | |
140 | ||
141 | /* stolen from fs/buffer.c */ | |
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 */ | |
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 | } |