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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/* Converts direct items to an unformatted node. Panics if file has no
15 tail. -ENOSPC if no disk space for conversion */
16/* path points to first direct item of the file regarless of how many of
17 them are there */
18int direct2indirect(struct reiserfs_transaction_handle *th, struct inode *inode,
19 struct path *path, struct buffer_head *unbh,
20 loff_t tail_offset)
21{
22 struct super_block *sb = inode->i_sb;
23 struct buffer_head *up_to_date_bh;
24 struct item_head *p_le_ih = PATH_PITEM_HEAD(path);
25 unsigned long total_tail = 0;
26 struct cpu_key end_key; /* Key to search for the last byte of the
27 converted item. */
28 struct item_head ind_ih; /* new indirect item to be inserted or
29 key of unfm pointer to be pasted */
30 int n_blk_size, n_retval; /* returned value for reiserfs_insert_item and clones */
31 unp_t unfm_ptr; /* Handle on an unformatted node
32 that will be inserted in the
33 tree. */
34
35 BUG_ON(!th->t_trans_id);
36
37 REISERFS_SB(sb)->s_direct2indirect++;
38
39 n_blk_size = sb->s_blocksize;
40
41 /* and key to search for append or insert pointer to the new
42 unformatted node. */
43 copy_item_head(&ind_ih, p_le_ih);
44 set_le_ih_k_offset(&ind_ih, tail_offset);
45 set_le_ih_k_type(&ind_ih, TYPE_INDIRECT);
46
47 /* Set the key to search for the place for new unfm pointer */
48 make_cpu_key(&end_key, inode, tail_offset, TYPE_INDIRECT, 4);
49
50 // FIXME: we could avoid this
51 if (search_for_position_by_key(sb, &end_key, path) == POSITION_FOUND) {
52 reiserfs_warning(sb, "PAP-14030: direct2indirect: "
53 "pasted or inserted byte exists in the tree %K. "
54 "Use fsck to repair.", &end_key);
55 pathrelse(path);
56 return -EIO;
57 }
58
59 p_le_ih = PATH_PITEM_HEAD(path);
60
61 unfm_ptr = cpu_to_le32(unbh->b_blocknr);
62
63 if (is_statdata_le_ih(p_le_ih)) {
64 /* Insert new indirect item. */
65 set_ih_free_space(&ind_ih, 0); /* delete at nearest future */
66 put_ih_item_len(&ind_ih, UNFM_P_SIZE);
67 PATH_LAST_POSITION(path)++;
68 n_retval =
69 reiserfs_insert_item(th, path, &end_key, &ind_ih, inode,
70 (char *)&unfm_ptr);
71 } else {
72 /* Paste into last indirect item of an object. */
73 n_retval = reiserfs_paste_into_item(th, path, &end_key, inode,
74 (char *)&unfm_ptr,
75 UNFM_P_SIZE);
76 }
77 if (n_retval) {
78 return n_retval;
79 }
80 // note: from here there are two keys which have matching first
81 // three key components. They only differ by the fourth one.
82
83 /* Set the key to search for the direct items of the file */
84 make_cpu_key(&end_key, inode, max_reiserfs_offset(inode), TYPE_DIRECT,
85 4);
86
87 /* Move bytes from the direct items to the new unformatted node
88 and delete them. */
89 while (1) {
90 int tail_size;
91
92 /* end_key.k_offset is set so, that we will always have found
93 last item of the file */
94 if (search_for_position_by_key(sb, &end_key, path) ==
95 POSITION_FOUND)
96 reiserfs_panic(sb,
97 "PAP-14050: direct2indirect: "
98 "direct item (%K) not found", &end_key);
99 p_le_ih = PATH_PITEM_HEAD(path);
100 RFALSE(!is_direct_le_ih(p_le_ih),
101 "vs-14055: direct item expected(%K), found %h",
102 &end_key, p_le_ih);
103 tail_size = (le_ih_k_offset(p_le_ih) & (n_blk_size - 1))
104 + ih_item_len(p_le_ih) - 1;
105
106 /* we only send the unbh pointer if the buffer is not up to date.
107 ** this avoids overwriting good data from writepage() with old data
108 ** from the disk or buffer cache
109 ** Special case: unbh->b_page will be NULL if we are coming through
110 ** DIRECT_IO handler here.
111 */
112 if (!unbh->b_page || buffer_uptodate(unbh)
113 || PageUptodate(unbh->b_page)) {
114 up_to_date_bh = NULL;
115 } else {
116 up_to_date_bh = unbh;
117 }
118 n_retval = reiserfs_delete_item(th, path, &end_key, inode,
119 up_to_date_bh);
120
121 total_tail += n_retval;
122 if (tail_size == n_retval)
123 // done: file does not have direct items anymore
124 break;
125
126 }
127 /* if we've copied bytes from disk into the page, we need to zero
128 ** out the unused part of the block (it was not up to date before)
129 */
130 if (up_to_date_bh) {
131 unsigned pgoff =
132 (tail_offset + total_tail - 1) & (PAGE_CACHE_SIZE - 1);
133 char *kaddr = kmap_atomic(up_to_date_bh->b_page, KM_USER0);
134 memset(kaddr + pgoff, 0, n_blk_size - total_tail);
135 kunmap_atomic(kaddr, KM_USER0);
136 }
137
138 REISERFS_I(inode)->i_first_direct_byte = U32_MAX;
139
140 return 0;
141}
142
143/* stolen from fs/buffer.c */
144void reiserfs_unmap_buffer(struct buffer_head *bh)
145{
146 lock_buffer(bh);
147 if (buffer_journaled(bh) || buffer_journal_dirty(bh)) {
148 BUG();
149 }
150 clear_buffer_dirty(bh);
151 /* Remove the buffer from whatever list it belongs to. We are mostly
152 interested in removing it from per-sb j_dirty_buffers list, to avoid
153 BUG() on attempt to write not mapped buffer */
154 if ((!list_empty(&bh->b_assoc_buffers) || bh->b_private) && bh->b_page) {
155 struct inode *inode = bh->b_page->mapping->host;
156 struct reiserfs_journal *j = SB_JOURNAL(inode->i_sb);
157 spin_lock(&j->j_dirty_buffers_lock);
158 list_del_init(&bh->b_assoc_buffers);
159 reiserfs_free_jh(bh);
160 spin_unlock(&j->j_dirty_buffers_lock);
161 }
162 clear_buffer_mapped(bh);
163 clear_buffer_req(bh);
164 clear_buffer_new(bh);
165 bh->b_bdev = NULL;
166 unlock_buffer(bh);
167}
168
169/* this first locks inode (neither reads nor sync are permitted),
170 reads tail through page cache, insert direct item. When direct item
171 inserted successfully inode is left locked. Return value is always
172 what we expect from it (number of cut bytes). But when tail remains
173 in the unformatted node, we set mode to SKIP_BALANCING and unlock
174 inode */
175int indirect2direct(struct reiserfs_transaction_handle *th, struct inode *p_s_inode, struct page *page, 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 =
204 le_ih_k_offset(&s_ih) - 1 + (ih_item_len(&s_ih) / UNFM_P_SIZE -
205 1) * p_s_sb->s_blocksize;
206 pos1 = pos;
207
208 // we are protected by i_sem. The tail can not disapper, not
209 // append can be done either
210 // we are in truncate or packing tail in file_release
211
212 tail = (char *)kmap(page); /* this can schedule */
213
214 if (path_changed(&s_ih, p_s_path)) {
215 /* re-search indirect item */
216 if (search_for_position_by_key(p_s_sb, p_s_item_key, p_s_path)
217 == POSITION_NOT_FOUND)
218 reiserfs_panic(p_s_sb,
219 "PAP-5520: indirect2direct: "
220 "item to be converted %K does not exist",
221 p_s_item_key);
222 copy_item_head(&s_ih, PATH_PITEM_HEAD(p_s_path));
223#ifdef CONFIG_REISERFS_CHECK
224 pos = le_ih_k_offset(&s_ih) - 1 +
225 (ih_item_len(&s_ih) / UNFM_P_SIZE -
226 1) * p_s_sb->s_blocksize;
227 if (pos != pos1)
228 reiserfs_panic(p_s_sb, "vs-5530: indirect2direct: "
229 "tail position changed while we were reading it");
230#endif
231 }
232
233 /* Set direct item header to insert. */
234 make_le_item_head(&s_ih, NULL, get_inode_item_key_version(p_s_inode),
235 pos1 + 1, TYPE_DIRECT, round_tail_len,
236 0xffff /*ih_free_space */ );
237
238 /* we want a pointer to the first byte of the tail in the page.
239 ** the page was locked and this part of the page was up to date when
240 ** indirect2direct was called, so we know the bytes are still valid
241 */
242 tail = tail + (pos & (PAGE_CACHE_SIZE - 1));
243
244 PATH_LAST_POSITION(p_s_path)++;
245
246 key = *p_s_item_key;
247 set_cpu_key_k_type(&key, TYPE_DIRECT);
248 key.key_length = 4;
249 /* Insert tail as new direct item in the tree */
250 if (reiserfs_insert_item(th, p_s_path, &key, &s_ih, p_s_inode,
251 tail ? tail : NULL) < 0) {
252 /* No disk memory. So we can not convert last unformatted node
253 to the direct item. In this case we used to adjust
254 indirect items's ih_free_space. Now ih_free_space is not
255 used, it would be ideal to write zeros to corresponding
256 unformatted node. For now i_size is considered as guard for
257 going out of file size */
258 kunmap(page);
259 return n_block_size - round_tail_len;
260 }
261 kunmap(page);
262
263 /* make sure to get the i_blocks changes from reiserfs_insert_item */
264 reiserfs_update_sd(th, p_s_inode);
265
266 // note: we have now the same as in above direct2indirect
267 // conversion: there are two keys which have matching first three
268 // key components. They only differ by the fouhth one.
269
270 /* We have inserted new direct item and must remove last
271 unformatted node. */
272 *p_c_mode = M_CUT;
273
274 /* we store position of first direct item in the in-core inode */
275 //mark_file_with_tail (p_s_inode, pos1 + 1);
276 REISERFS_I(p_s_inode)->i_first_direct_byte = pos1 + 1;
277
278 return n_block_size - round_tail_len;
279}