summaryrefslogtreecommitdiffstats
path: root/fs/reiserfs/tail_conversion.c
blob: c92e124f628ec13417a76de58c71817e08ab0e11 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
/*
 * Copyright 1999 Hans Reiser, see reiserfs/README for licensing and copyright details
 */

#include <linux/config.h>
#include <linux/time.h>
#include <linux/pagemap.h>
#include <linux/buffer_head.h>
#include <linux/reiserfs_fs.h>

/* access to tail : when one is going to read tail it must make sure, that is not running.
 direct2indirect and indirect2direct can not run concurrently */

/* Converts direct items to an unformatted node. Panics if file has no
   tail. -ENOSPC if no disk space for conversion */
/* path points to first direct item of the file regarless of how many of
   them are there */
int direct2indirect(struct reiserfs_transaction_handle *th, struct inode *inode,
		    struct path *path, struct buffer_head *unbh,
		    loff_t tail_offset)
{
	struct super_block *sb = inode->i_sb;
	struct buffer_head *up_to_date_bh;
	struct item_head *p_le_ih = PATH_PITEM_HEAD(path);
	unsigned long total_tail = 0;
	struct cpu_key end_key;	/* Key to search for the last byte of the
				   converted item. */
	struct item_head ind_ih;	/* new indirect item to be inserted or
					   key of unfm pointer to be pasted */
	int n_blk_size, n_retval;	/* returned value for reiserfs_insert_item and clones */
	unp_t unfm_ptr;		/* Handle on an unformatted node
				   that will be inserted in the
				   tree. */

	BUG_ON(!th->t_trans_id);

	REISERFS_SB(sb)->s_direct2indirect++;

	n_blk_size = sb->s_blocksize;

	/* and key to search for append or insert pointer to the new
	   unformatted node. */
	copy_item_head(&ind_ih, p_le_ih);
	set_le_ih_k_offset(&ind_ih, tail_offset);
	set_le_ih_k_type(&ind_ih, TYPE_INDIRECT);

	/* Set the key to search for the place for new unfm pointer */
	make_cpu_key(&end_key, inode, tail_offset, TYPE_INDIRECT, 4);

	// FIXME: we could avoid this 
	if (search_for_position_by_key(sb, &end_key, path) == POSITION_FOUND) {
		reiserfs_warning(sb, "PAP-14030: direct2indirect: "
				 "pasted or inserted byte exists in the tree %K. "
				 "Use fsck to repair.", &end_key);
		pathrelse(path);
		return -EIO;
	}

	p_le_ih = PATH_PITEM_HEAD(path);

	unfm_ptr = cpu_to_le32(unbh->b_blocknr);

	if (is_statdata_le_ih(p_le_ih)) {
		/* Insert new indirect item. */
		set_ih_free_space(&ind_ih, 0);	/* delete at nearest future */
		put_ih_item_len(&ind_ih, UNFM_P_SIZE);
		PATH_LAST_POSITION(path)++;
		n_retval =
		    reiserfs_insert_item(th, path, &end_key, &ind_ih, inode,
					 (char *)&unfm_ptr);
	} else {
		/* Paste into last indirect item of an object. */
		n_retval = reiserfs_paste_into_item(th, path, &end_key, inode,
						    (char *)&unfm_ptr,
						    UNFM_P_SIZE);
	}
	if (n_retval) {
		return n_retval;
	}
	// note: from here there are two keys which have matching first
	// three key components. They only differ by the fourth one.

	/* Set the key to search for the direct items of the file */
	make_cpu_key(&end_key, inode, max_reiserfs_offset(inode), TYPE_DIRECT,
		     4);

	/* Move bytes from the direct items to the new unformatted node
	   and delete them. */
	while (1) {
		int tail_size;

		/* end_key.k_offset is set so, that we will always have found
		   last item of the file */
		if (search_for_position_by_key(sb, &end_key, path) ==
		    POSITION_FOUND)
			reiserfs_panic(sb,
				       "PAP-14050: direct2indirect: "
				       "direct item (%K) not found", &end_key);
		p_le_ih = PATH_PITEM_HEAD(path);
		RFALSE(!is_direct_le_ih(p_le_ih),
		       "vs-14055: direct item expected(%K), found %h",
		       &end_key, p_le_ih);
		tail_size = (le_ih_k_offset(p_le_ih) & (n_blk_size - 1))
		    + ih_item_len(p_le_ih) - 1;

		/* we only send the unbh pointer if the buffer is not up to date.
		 ** this avoids overwriting good data from writepage() with old data
		 ** from the disk or buffer cache
		 ** Special case: unbh->b_page will be NULL if we are coming through
		 ** DIRECT_IO handler here.
		 */
		if (!unbh->b_page || buffer_uptodate(unbh)
		    || PageUptodate(unbh->b_page)) {
			up_to_date_bh = NULL;
		} else {
			up_to_date_bh = unbh;
		}
		n_retval = reiserfs_delete_item(th, path, &end_key, inode,
						up_to_date_bh);

		total_tail += n_retval;
		if (tail_size == n_retval)
			// done: file does not have direct items anymore
			break;

	}
	/* if we've copied bytes from disk into the page, we need to zero
	 ** out the unused part of the block (it was not up to date before)
	 */
	if (up_to_date_bh) {
		unsigned pgoff =
		    (tail_offset + total_tail - 1) & (PAGE_CACHE_SIZE - 1);
		char *kaddr = kmap_atomic(up_to_date_bh->b_page, KM_USER0);
		memset(kaddr + pgoff, 0, n_blk_size - total_tail);
		kunmap_atomic(kaddr, KM_USER0);
	}

	REISERFS_I(inode)->i_first_direct_byte = U32_MAX;

	return 0;
}

/* stolen from fs/buffer.c */
void reiserfs_unmap_buffer(struct buffer_head *bh)
{
	lock_buffer(bh);
	if (buffer_journaled(bh) || buffer_journal_dirty(bh)) {
		BUG();
	}
	clear_buffer_dirty(bh);
	/* Remove the buffer from whatever list it belongs to. We are mostly
	   interested in removing it from per-sb j_dirty_buffers list, to avoid
	   BUG() on attempt to write not mapped buffer */
	if ((!list_empty(&bh->b_assoc_buffers) || bh->b_private) && bh->b_page) {
		struct inode *inode = bh->b_page->mapping->host;
		struct reiserfs_journal *j = SB_JOURNAL(inode->i_sb);
		spin_lock(&j->j_dirty_buffers_lock);
		list_del_init(&bh->b_assoc_buffers);
		reiserfs_free_jh(bh);
		spin_unlock(&j->j_dirty_buffers_lock);
	}
	clear_buffer_mapped(bh);
	clear_buffer_req(bh);
	clear_buffer_new(bh);
	bh->b_bdev = NULL;
	unlock_buffer(bh);
}

/* this first locks inode (neither reads nor sync are permitted),
   reads tail through page cache, insert direct item. When direct item
   inserted successfully inode is left locked. Return value is always
   what we expect from it (number of cut bytes). But when tail remains
   in the unformatted node, we set mode to SKIP_BALANCING and unlock
   inode */
int indirect2direct(struct reiserfs_transaction_handle *th, struct inode *p_s_inode, struct page *page, struct path *p_s_path,	/* path to the indirect item. */
		    const struct cpu_key *p_s_item_key,	/* Key to look for unformatted node pointer to be cut. */
		    loff_t n_new_file_size,	/* New file size. */
		    char *p_c_mode)
{
	struct super_block *p_s_sb = p_s_inode->i_sb;
	struct item_head s_ih;
	unsigned long n_block_size = p_s_sb->s_blocksize;
	char *tail;
	int tail_len, round_tail_len;
	loff_t pos, pos1;	/* position of first byte of the tail */
	struct cpu_key key;

	BUG_ON(!th->t_trans_id);

	REISERFS_SB(p_s_sb)->s_indirect2direct++;

	*p_c_mode = M_SKIP_BALANCING;

	/* store item head path points to. */
	copy_item_head(&s_ih, PATH_PITEM_HEAD(p_s_path));

	tail_len = (n_new_file_size & (n_block_size - 1));
	if (get_inode_sd_version(p_s_inode) == STAT_DATA_V2)
		round_tail_len = ROUND_UP(tail_len);
	else
		round_tail_len = tail_len;

	pos =
	    le_ih_k_offset(&s_ih) - 1 + (ih_item_len(&s_ih) / UNFM_P_SIZE -
					 1) * p_s_sb->s_blocksize;
	pos1 = pos;

	// we are protected by i_sem. The tail can not disapper, not
	// append can be done either
	// we are in truncate or packing tail in file_release

	tail = (char *)kmap(page);	/* this can schedule */

	if (path_changed(&s_ih, p_s_path)) {
		/* re-search indirect item */
		if (search_for_position_by_key(p_s_sb, p_s_item_key, p_s_path)
		    == POSITION_NOT_FOUND)
			reiserfs_panic(p_s_sb,
				       "PAP-5520: indirect2direct: "
				       "item to be converted %K does not exist",
				       p_s_item_key);
		copy_item_head(&s_ih, PATH_PITEM_HEAD(p_s_path));
#ifdef CONFIG_REISERFS_CHECK
		pos = le_ih_k_offset(&s_ih) - 1 +
		    (ih_item_len(&s_ih) / UNFM_P_SIZE -
		     1) * p_s_sb->s_blocksize;
		if (pos != pos1)
			reiserfs_panic(p_s_sb, "vs-5530: indirect2direct: "
				       "tail position changed while we were reading it");
#endif
	}

	/* Set direct item header to insert. */
	make_le_item_head(&s_ih, NULL, get_inode_item_key_version(p_s_inode),
			  pos1 + 1, TYPE_DIRECT, round_tail_len,
			  0xffff /*ih_free_space */ );

	/* we want a pointer to the first byte of the tail in the page.
	 ** the page was locked and this part of the page was up to date when
	 ** indirect2direct was called, so we know the bytes are still valid
	 */
	tail = tail + (pos & (PAGE_CACHE_SIZE - 1));

	PATH_LAST_POSITION(p_s_path)++;

	key = *p_s_item_key;
	set_cpu_key_k_type(&key, TYPE_DIRECT);
	key.key_length = 4;
	/* Insert tail as new direct item in the tree */
	if (reiserfs_insert_item(th, p_s_path, &key, &s_ih, p_s_inode,
				 tail ? tail : NULL) < 0) {
		/* No disk memory. So we can not convert last unformatted node
		   to the direct item.  In this case we used to adjust
		   indirect items's ih_free_space. Now ih_free_space is not
		   used, it would be ideal to write zeros to corresponding
		   unformatted node. For now i_size is considered as guard for
		   going out of file size */
		kunmap(page);
		return n_block_size - round_tail_len;
	}
	kunmap(page);

	/* make sure to get the i_blocks changes from reiserfs_insert_item */
	reiserfs_update_sd(th, p_s_inode);

	// note: we have now the same as in above direct2indirect
	// conversion: there are two keys which have matching first three
	// key components. They only differ by the fouhth one.

	/* We have inserted new direct item and must remove last
	   unformatted node. */
	*p_c_mode = M_CUT;

	/* we store position of first direct item in the in-core inode */
	//mark_file_with_tail (p_s_inode, pos1 + 1);
	REISERFS_I(p_s_inode)->i_first_direct_byte = pos1 + 1;

	return n_block_size - round_tail_len;
}