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1da177e4 LT |
1 | /* |
2 | * Copyright 1999 Hans Reiser, see reiserfs/README for licensing and copyright details | |
3 | */ | |
4 | ||
5 | #include <linux/config.h> | |
6 | #include <linux/time.h> | |
7 | #include <linux/pagemap.h> | |
8 | #include <linux/buffer_head.h> | |
9 | #include <linux/reiserfs_fs.h> | |
10 | ||
11 | /* access to tail : when one is going to read tail it must make sure, that is not running. | |
12 | direct2indirect and indirect2direct can not run concurrently */ | |
13 | ||
14 | ||
15 | /* Converts direct items to an unformatted node. Panics if file has no | |
16 | tail. -ENOSPC if no disk space for conversion */ | |
17 | /* path points to first direct item of the file regarless of how many of | |
18 | them are there */ | |
19 | int direct2indirect (struct reiserfs_transaction_handle *th, struct inode * inode, | |
20 | struct path * path, struct buffer_head * unbh, | |
21 | loff_t tail_offset) | |
22 | { | |
23 | struct super_block * sb = inode->i_sb; | |
24 | struct buffer_head *up_to_date_bh ; | |
25 | struct item_head * p_le_ih = PATH_PITEM_HEAD (path); | |
26 | unsigned long total_tail = 0 ; | |
27 | struct cpu_key end_key; /* Key to search for the last byte of the | |
28 | converted item. */ | |
29 | struct item_head ind_ih; /* new indirect item to be inserted or | |
30 | key of unfm pointer to be pasted */ | |
31 | int n_blk_size, | |
32 | n_retval; /* returned value for reiserfs_insert_item and clones */ | |
33 | unp_t unfm_ptr; /* Handle on an unformatted node | |
34 | that will be inserted in the | |
35 | tree. */ | |
36 | ||
37 | BUG_ON (!th->t_trans_id); | |
38 | ||
39 | REISERFS_SB(sb)->s_direct2indirect ++; | |
40 | ||
41 | n_blk_size = sb->s_blocksize; | |
42 | ||
43 | /* and key to search for append or insert pointer to the new | |
44 | unformatted node. */ | |
45 | copy_item_head (&ind_ih, p_le_ih); | |
46 | set_le_ih_k_offset (&ind_ih, tail_offset); | |
47 | set_le_ih_k_type (&ind_ih, TYPE_INDIRECT); | |
48 | ||
49 | /* Set the key to search for the place for new unfm pointer */ | |
50 | make_cpu_key (&end_key, inode, tail_offset, TYPE_INDIRECT, 4); | |
51 | ||
52 | // FIXME: we could avoid this | |
53 | if ( search_for_position_by_key (sb, &end_key, path) == POSITION_FOUND ) { | |
54 | reiserfs_warning (sb, "PAP-14030: direct2indirect: " | |
55 | "pasted or inserted byte exists in the tree %K. " | |
56 | "Use fsck to repair.", &end_key); | |
57 | pathrelse(path); | |
58 | return -EIO; | |
59 | } | |
60 | ||
61 | p_le_ih = PATH_PITEM_HEAD (path); | |
62 | ||
63 | unfm_ptr = cpu_to_le32 (unbh->b_blocknr); | |
64 | ||
65 | if ( is_statdata_le_ih (p_le_ih) ) { | |
66 | /* Insert new indirect item. */ | |
67 | set_ih_free_space (&ind_ih, 0); /* delete at nearest future */ | |
68 | put_ih_item_len( &ind_ih, UNFM_P_SIZE ); | |
69 | PATH_LAST_POSITION (path)++; | |
70 | n_retval = reiserfs_insert_item (th, path, &end_key, &ind_ih, inode, | |
71 | (char *)&unfm_ptr); | |
72 | } else { | |
73 | /* Paste into last indirect item of an object. */ | |
74 | n_retval = reiserfs_paste_into_item(th, path, &end_key, inode, | |
75 | (char *)&unfm_ptr, UNFM_P_SIZE); | |
76 | } | |
77 | if ( n_retval ) { | |
78 | return n_retval; | |
79 | } | |
80 | ||
81 | // note: from here there are two keys which have matching first | |
82 | // three key components. They only differ by the fourth one. | |
83 | ||
84 | ||
85 | /* Set the key to search for the direct items of the file */ | |
86 | make_cpu_key (&end_key, inode, max_reiserfs_offset (inode), TYPE_DIRECT, 4); | |
87 | ||
88 | /* Move bytes from the direct items to the new unformatted node | |
89 | and delete them. */ | |
90 | while (1) { | |
91 | int tail_size; | |
92 | ||
93 | /* end_key.k_offset is set so, that we will always have found | |
94 | last item of the file */ | |
95 | if ( search_for_position_by_key (sb, &end_key, path) == POSITION_FOUND ) | |
96 | reiserfs_panic (sb, "PAP-14050: direct2indirect: " | |
97 | "direct item (%K) not found", &end_key); | |
98 | p_le_ih = PATH_PITEM_HEAD (path); | |
99 | RFALSE( !is_direct_le_ih (p_le_ih), | |
100 | "vs-14055: direct item expected(%K), found %h", | |
101 | &end_key, p_le_ih); | |
102 | tail_size = (le_ih_k_offset (p_le_ih) & (n_blk_size - 1)) | |
103 | + ih_item_len(p_le_ih) - 1; | |
104 | ||
105 | /* we only send the unbh pointer if the buffer is not up to date. | |
106 | ** this avoids overwriting good data from writepage() with old data | |
107 | ** from the disk or buffer cache | |
108 | ** Special case: unbh->b_page will be NULL if we are coming through | |
109 | ** DIRECT_IO handler here. | |
110 | */ | |
111 | if (!unbh->b_page || buffer_uptodate(unbh) || PageUptodate(unbh->b_page)) { | |
112 | up_to_date_bh = NULL ; | |
113 | } else { | |
114 | up_to_date_bh = unbh ; | |
115 | } | |
116 | n_retval = reiserfs_delete_item (th, path, &end_key, inode, | |
117 | up_to_date_bh) ; | |
118 | ||
119 | total_tail += n_retval ; | |
120 | if (tail_size == n_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 = (tail_offset + total_tail - 1) & (PAGE_CACHE_SIZE - 1); | |
130 | char *kaddr=kmap_atomic(up_to_date_bh->b_page, KM_USER0); | |
131 | memset(kaddr + pgoff, 0, n_blk_size - total_tail) ; | |
132 | kunmap_atomic(kaddr, KM_USER0); | |
133 | } | |
134 | ||
135 | REISERFS_I(inode)->i_first_direct_byte = U32_MAX; | |
136 | ||
137 | return 0; | |
138 | } | |
139 | ||
140 | ||
141 | /* stolen from fs/buffer.c */ | |
142 | void reiserfs_unmap_buffer(struct buffer_head *bh) { | |
143 | lock_buffer(bh) ; | |
144 | if (buffer_journaled(bh) || buffer_journal_dirty(bh)) { | |
145 | BUG() ; | |
146 | } | |
147 | clear_buffer_dirty(bh) ; | |
148 | /* Remove the buffer from whatever list it belongs to. We are mostly | |
149 | interested in removing it from per-sb j_dirty_buffers list, to avoid | |
150 | BUG() on attempt to write not mapped buffer */ | |
151 | if ( (!list_empty(&bh->b_assoc_buffers) || bh->b_private) && bh->b_page) { | |
152 | struct inode *inode = bh->b_page->mapping->host; | |
153 | struct reiserfs_journal *j = SB_JOURNAL(inode->i_sb); | |
154 | spin_lock(&j->j_dirty_buffers_lock); | |
155 | list_del_init(&bh->b_assoc_buffers); | |
156 | reiserfs_free_jh(bh); | |
157 | spin_unlock(&j->j_dirty_buffers_lock); | |
158 | } | |
159 | clear_buffer_mapped(bh) ; | |
160 | clear_buffer_req(bh) ; | |
161 | clear_buffer_new(bh); | |
162 | bh->b_bdev = NULL; | |
163 | unlock_buffer(bh) ; | |
164 | } | |
165 | ||
166 | /* this first locks inode (neither reads nor sync are permitted), | |
167 | reads tail through page cache, insert direct item. When direct item | |
168 | inserted successfully inode is left locked. Return value is always | |
169 | what we expect from it (number of cut bytes). But when tail remains | |
170 | in the unformatted node, we set mode to SKIP_BALANCING and unlock | |
171 | inode */ | |
172 | int indirect2direct (struct reiserfs_transaction_handle *th, | |
173 | struct inode * p_s_inode, | |
174 | struct page *page, | |
175 | struct path * p_s_path, /* path to the indirect item. */ | |
176 | const struct cpu_key * p_s_item_key, /* Key to look for unformatted node pointer to be cut. */ | |
177 | loff_t n_new_file_size, /* New file size. */ | |
178 | char * p_c_mode) | |
179 | { | |
180 | struct super_block * p_s_sb = p_s_inode->i_sb; | |
181 | struct item_head s_ih; | |
182 | unsigned long n_block_size = p_s_sb->s_blocksize; | |
183 | char * tail; | |
184 | int tail_len, round_tail_len; | |
185 | loff_t pos, pos1; /* position of first byte of the tail */ | |
186 | struct cpu_key key; | |
187 | ||
188 | BUG_ON (!th->t_trans_id); | |
189 | ||
190 | REISERFS_SB(p_s_sb)->s_indirect2direct ++; | |
191 | ||
192 | *p_c_mode = M_SKIP_BALANCING; | |
193 | ||
194 | /* store item head path points to. */ | |
195 | copy_item_head (&s_ih, PATH_PITEM_HEAD(p_s_path)); | |
196 | ||
197 | tail_len = (n_new_file_size & (n_block_size - 1)); | |
198 | if (get_inode_sd_version (p_s_inode) == STAT_DATA_V2) | |
199 | round_tail_len = ROUND_UP (tail_len); | |
200 | else | |
201 | round_tail_len = tail_len; | |
202 | ||
203 | pos = le_ih_k_offset (&s_ih) - 1 + (ih_item_len(&s_ih) / UNFM_P_SIZE - 1) * p_s_sb->s_blocksize; | |
204 | pos1 = pos; | |
205 | ||
206 | // we are protected by i_sem. The tail can not disapper, not | |
207 | // append can be done either | |
208 | // we are in truncate or packing tail in file_release | |
209 | ||
210 | tail = (char *)kmap(page) ; /* this can schedule */ | |
211 | ||
212 | if (path_changed (&s_ih, p_s_path)) { | |
213 | /* re-search indirect item */ | |
214 | if ( search_for_position_by_key (p_s_sb, p_s_item_key, p_s_path) == POSITION_NOT_FOUND ) | |
215 | reiserfs_panic(p_s_sb, "PAP-5520: indirect2direct: " | |
216 | "item to be converted %K does not exist", p_s_item_key); | |
217 | copy_item_head(&s_ih, PATH_PITEM_HEAD(p_s_path)); | |
218 | #ifdef CONFIG_REISERFS_CHECK | |
219 | pos = le_ih_k_offset (&s_ih) - 1 + | |
220 | (ih_item_len(&s_ih) / UNFM_P_SIZE - 1) * p_s_sb->s_blocksize; | |
221 | if (pos != pos1) | |
222 | reiserfs_panic (p_s_sb, "vs-5530: indirect2direct: " | |
223 | "tail position changed while we were reading it"); | |
224 | #endif | |
225 | } | |
226 | ||
227 | ||
228 | /* Set direct item header to insert. */ | |
229 | make_le_item_head (&s_ih, NULL, get_inode_item_key_version (p_s_inode), pos1 + 1, | |
230 | TYPE_DIRECT, round_tail_len, 0xffff/*ih_free_space*/); | |
231 | ||
232 | /* we want a pointer to the first byte of the tail in the page. | |
233 | ** the page was locked and this part of the page was up to date when | |
234 | ** indirect2direct was called, so we know the bytes are still valid | |
235 | */ | |
236 | tail = tail + (pos & (PAGE_CACHE_SIZE - 1)) ; | |
237 | ||
238 | PATH_LAST_POSITION(p_s_path)++; | |
239 | ||
240 | key = *p_s_item_key; | |
241 | set_cpu_key_k_type (&key, TYPE_DIRECT); | |
242 | key.key_length = 4; | |
243 | /* Insert tail as new direct item in the tree */ | |
244 | if ( reiserfs_insert_item(th, p_s_path, &key, &s_ih, p_s_inode, | |
245 | tail ? tail : NULL) < 0 ) { | |
246 | /* No disk memory. So we can not convert last unformatted node | |
247 | to the direct item. In this case we used to adjust | |
248 | indirect items's ih_free_space. Now ih_free_space is not | |
249 | used, it would be ideal to write zeros to corresponding | |
250 | unformatted node. For now i_size is considered as guard for | |
251 | going out of file size */ | |
252 | kunmap(page) ; | |
253 | return n_block_size - round_tail_len; | |
254 | } | |
255 | kunmap(page) ; | |
256 | ||
257 | /* make sure to get the i_blocks changes from reiserfs_insert_item */ | |
258 | reiserfs_update_sd(th, p_s_inode); | |
259 | ||
260 | // note: we have now the same as in above direct2indirect | |
261 | // conversion: there are two keys which have matching first three | |
262 | // key components. They only differ by the fouhth one. | |
263 | ||
264 | /* We have inserted new direct item and must remove last | |
265 | unformatted node. */ | |
266 | *p_c_mode = M_CUT; | |
267 | ||
268 | /* we store position of first direct item in the in-core inode */ | |
269 | //mark_file_with_tail (p_s_inode, pos1 + 1); | |
270 | REISERFS_I(p_s_inode)->i_first_direct_byte = pos1 + 1; | |
271 | ||
272 | return n_block_size - round_tail_len; | |
273 | } | |
274 | ||
275 | ||
276 |