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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 | } |
281 |
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