1/*
2 * Copyright 1999 Hans Reiser, see reiserfs/README for licensing and copyright
3 * details
4 */
5
6#include <linux/time.h>
7#include <linux/pagemap.h>
8#include <linux/buffer_head.h>
9#include "reiserfs.h"
10
11/*
12 * access to tail : when one is going to read tail it must make sure, that is
13 * not running.  direct2indirect and indirect2direct can not run concurrently
14 */
15
16/*
17 * Converts direct items to an unformatted node. Panics if file has no
18 * tail. -ENOSPC if no disk space for conversion
19 */
20/*
21 * path points to first direct item of the file regardless of how many of
22 * them are there
23 */
24int direct2indirect(struct reiserfs_transaction_handle *th, struct inode *inode,
25		    struct treepath *path, struct buffer_head *unbh,
26		    loff_t tail_offset)
27{
28	struct super_block *sb = inode->i_sb;
29	struct buffer_head *up_to_date_bh;
30	struct item_head *p_le_ih = tp_item_head(path);
31	unsigned long total_tail = 0;
32
33	/* Key to search for the last byte of the converted item. */
34	struct cpu_key end_key;
35
36	/*
37	 * new indirect item to be inserted or key
38	 * of unfm pointer to be pasted
39	 */
40	struct item_head ind_ih;
41	int blk_size;
42	/* returned value for reiserfs_insert_item and clones */
43	int  retval;
44	/* Handle on an unformatted node that will be inserted in the tree. */
45	unp_t unfm_ptr;
46
47	BUG_ON(!th->t_trans_id);
48
49	REISERFS_SB(sb)->s_direct2indirect++;
50
51	blk_size = sb->s_blocksize;
52
53	/*
54	 * and key to search for append or insert pointer to the new
55	 * unformatted node.
56	 */
57	copy_item_head(&ind_ih, p_le_ih);
58	set_le_ih_k_offset(&ind_ih, tail_offset);
59	set_le_ih_k_type(&ind_ih, TYPE_INDIRECT);
60
61	/* Set the key to search for the place for new unfm pointer */
62	make_cpu_key(&end_key, inode, tail_offset, TYPE_INDIRECT, 4);
63
64	/* FIXME: we could avoid this */
65	if (search_for_position_by_key(sb, &end_key, path) == POSITION_FOUND) {
66		reiserfs_error(sb, "PAP-14030",
67			       "pasted or inserted byte exists in "
68			       "the tree %K. Use fsck to repair.", &end_key);
69		pathrelse(path);
70		return -EIO;
71	}
72
73	p_le_ih = tp_item_head(path);
74
75	unfm_ptr = cpu_to_le32(unbh->b_blocknr);
76
77	if (is_statdata_le_ih(p_le_ih)) {
78		/* Insert new indirect item. */
79		set_ih_free_space(&ind_ih, 0);	/* delete at nearest future */
80		put_ih_item_len(&ind_ih, UNFM_P_SIZE);
81		PATH_LAST_POSITION(path)++;
82		retval =
83		    reiserfs_insert_item(th, path, &end_key, &ind_ih, inode,
84					 (char *)&unfm_ptr);
85	} else {
86		/* Paste into last indirect item of an object. */
87		retval = reiserfs_paste_into_item(th, path, &end_key, inode,
88						    (char *)&unfm_ptr,
89						    UNFM_P_SIZE);
90	}
91	if (retval) {
92		return retval;
93	}
94	/*
95	 * note: from here there are two keys which have matching first
96	 *  three key components. They only differ by the fourth one.
97	 */
98
99	/* Set the key to search for the direct items of the file */
100	make_cpu_key(&end_key, inode, max_reiserfs_offset(inode), TYPE_DIRECT,
101		     4);
102
103	/*
104	 * Move bytes from the direct items to the new unformatted node
105	 * and delete them.
106	 */
107	while (1) {
108		int tail_size;
109
110		/*
111		 * end_key.k_offset is set so, that we will always have found
112		 * last item of the file
113		 */
114		if (search_for_position_by_key(sb, &end_key, path) ==
115		    POSITION_FOUND)
116			reiserfs_panic(sb, "PAP-14050",
117				       "direct item (%K) not found", &end_key);
118		p_le_ih = tp_item_head(path);
119		RFALSE(!is_direct_le_ih(p_le_ih),
120		       "vs-14055: direct item expected(%K), found %h",
121		       &end_key, p_le_ih);
122		tail_size = (le_ih_k_offset(p_le_ih) & (blk_size - 1))
123		    + ih_item_len(p_le_ih) - 1;
124
125		/*
126		 * we only send the unbh pointer if the buffer is not
127		 * up to date.  this avoids overwriting good data from
128		 * writepage() with old data from the disk or buffer cache
129		 * Special case: unbh->b_page will be NULL if we are coming
130		 * through DIRECT_IO handler here.
131		 */
132		if (!unbh->b_page || buffer_uptodate(unbh)
133		    || PageUptodate(unbh->b_page)) {
134			up_to_date_bh = NULL;
135		} else {
136			up_to_date_bh = unbh;
137		}
138		retval = reiserfs_delete_item(th, path, &end_key, inode,
139						up_to_date_bh);
140
141		total_tail += retval;
142
143		/* done: file does not have direct items anymore */
144		if (tail_size == retval)
145			break;
146
147	}
148	/*
149	 * if we've copied bytes from disk into the page, we need to zero
150	 * out the unused part of the block (it was not up to date before)
151	 */
152	if (up_to_date_bh) {
153		unsigned pgoff =
154		    (tail_offset + total_tail - 1) & (PAGE_CACHE_SIZE - 1);
155		char *kaddr = kmap_atomic(up_to_date_bh->b_page);
156		memset(kaddr + pgoff, 0, blk_size - total_tail);
157		kunmap_atomic(kaddr);
158	}
159
160	REISERFS_I(inode)->i_first_direct_byte = U32_MAX;
161
162	return 0;
163}
164
165/* stolen from fs/buffer.c */
166void reiserfs_unmap_buffer(struct buffer_head *bh)
167{
168	lock_buffer(bh);
169	if (buffer_journaled(bh) || buffer_journal_dirty(bh)) {
170		BUG();
171	}
172	clear_buffer_dirty(bh);
173	/*
174	 * Remove the buffer from whatever list it belongs to. We are mostly
175	 * interested in removing it from per-sb j_dirty_buffers list, to avoid
176	 * BUG() on attempt to write not mapped buffer
177	 */
178	if ((!list_empty(&bh->b_assoc_buffers) || bh->b_private) && bh->b_page) {
179		struct inode *inode = bh->b_page->mapping->host;
180		struct reiserfs_journal *j = SB_JOURNAL(inode->i_sb);
181		spin_lock(&j->j_dirty_buffers_lock);
182		list_del_init(&bh->b_assoc_buffers);
183		reiserfs_free_jh(bh);
184		spin_unlock(&j->j_dirty_buffers_lock);
185	}
186	clear_buffer_mapped(bh);
187	clear_buffer_req(bh);
188	clear_buffer_new(bh);
189	bh->b_bdev = NULL;
190	unlock_buffer(bh);
191}
192
193/*
194 * this first locks inode (neither reads nor sync are permitted),
195 * reads tail through page cache, insert direct item. When direct item
196 * inserted successfully inode is left locked. Return value is always
197 * what we expect from it (number of cut bytes). But when tail remains
198 * in the unformatted node, we set mode to SKIP_BALANCING and unlock
199 * inode
200 */
201int indirect2direct(struct reiserfs_transaction_handle *th,
202		    struct inode *inode, struct page *page,
203		    struct treepath *path,	/* path to the indirect item. */
204		    const struct cpu_key *item_key,	/* Key to look for
205							 * unformatted node
206							 * pointer to be cut. */
207		    loff_t n_new_file_size,	/* New file size. */
208		    char *mode)
209{
210	struct super_block *sb = inode->i_sb;
211	struct item_head s_ih;
212	unsigned long block_size = sb->s_blocksize;
213	char *tail;
214	int tail_len, round_tail_len;
215	loff_t pos, pos1;	/* position of first byte of the tail */
216	struct cpu_key key;
217
218	BUG_ON(!th->t_trans_id);
219
220	REISERFS_SB(sb)->s_indirect2direct++;
221
222	*mode = M_SKIP_BALANCING;
223
224	/* store item head path points to. */
225	copy_item_head(&s_ih, tp_item_head(path));
226
227	tail_len = (n_new_file_size & (block_size - 1));
228	if (get_inode_sd_version(inode) == STAT_DATA_V2)
229		round_tail_len = ROUND_UP(tail_len);
230	else
231		round_tail_len = tail_len;
232
233	pos =
234	    le_ih_k_offset(&s_ih) - 1 + (ih_item_len(&s_ih) / UNFM_P_SIZE -
235					 1) * sb->s_blocksize;
236	pos1 = pos;
237
238	/*
239	 * we are protected by i_mutex. The tail can not disapper, not
240	 * append can be done either
241	 * we are in truncate or packing tail in file_release
242	 */
243
244	tail = (char *)kmap(page);	/* this can schedule */
245
246	if (path_changed(&s_ih, path)) {
247		/* re-search indirect item */
248		if (search_for_position_by_key(sb, item_key, path)
249		    == POSITION_NOT_FOUND)
250			reiserfs_panic(sb, "PAP-5520",
251				       "item to be converted %K does not exist",
252				       item_key);
253		copy_item_head(&s_ih, tp_item_head(path));
254#ifdef CONFIG_REISERFS_CHECK
255		pos = le_ih_k_offset(&s_ih) - 1 +
256		    (ih_item_len(&s_ih) / UNFM_P_SIZE -
257		     1) * sb->s_blocksize;
258		if (pos != pos1)
259			reiserfs_panic(sb, "vs-5530", "tail position "
260				       "changed while we were reading it");
261#endif
262	}
263
264	/* Set direct item header to insert. */
265	make_le_item_head(&s_ih, NULL, get_inode_item_key_version(inode),
266			  pos1 + 1, TYPE_DIRECT, round_tail_len,
267			  0xffff /*ih_free_space */ );
268
269	/*
270	 * we want a pointer to the first byte of the tail in the page.
271	 * the page was locked and this part of the page was up to date when
272	 * indirect2direct was called, so we know the bytes are still valid
273	 */
274	tail = tail + (pos & (PAGE_CACHE_SIZE - 1));
275
276	PATH_LAST_POSITION(path)++;
277
278	key = *item_key;
279	set_cpu_key_k_type(&key, TYPE_DIRECT);
280	key.key_length = 4;
281	/* Insert tail as new direct item in the tree */
282	if (reiserfs_insert_item(th, path, &key, &s_ih, inode,
283				 tail ? tail : NULL) < 0) {
284		/*
285		 * No disk memory. So we can not convert last unformatted node
286		 * to the direct item.  In this case we used to adjust
287		 * indirect items's ih_free_space. Now ih_free_space is not
288		 * used, it would be ideal to write zeros to corresponding
289		 * unformatted node. For now i_size is considered as guard for
290		 * going out of file size
291		 */
292		kunmap(page);
293		return block_size - round_tail_len;
294	}
295	kunmap(page);
296
297	/* make sure to get the i_blocks changes from reiserfs_insert_item */
298	reiserfs_update_sd(th, inode);
299
300	/*
301	 * note: we have now the same as in above direct2indirect
302	 * conversion: there are two keys which have matching first three
303	 * key components. They only differ by the fourth one.
304	 */
305
306	/*
307	 * We have inserted new direct item and must remove last
308	 * unformatted node.
309	 */
310	*mode = M_CUT;
311
312	/* we store position of first direct item in the in-core inode */
313	/* mark_file_with_tail (inode, pos1 + 1); */
314	REISERFS_I(inode)->i_first_direct_byte = pos1 + 1;
315
316	return block_size - round_tail_len;
317}
318