xref: /openbmc/linux/fs/reiserfs/tail_conversion.c (revision 2cf1c348)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright 1999 Hans Reiser, see reiserfs/README for licensing and copyright
4  * details
5  */
6 
7 #include <linux/time.h>
8 #include <linux/pagemap.h>
9 #include <linux/buffer_head.h>
10 #include "reiserfs.h"
11 
12 /*
13  * access to tail : when one is going to read tail it must make sure, that is
14  * not running.  direct2indirect and indirect2direct can not run concurrently
15  */
16 
17 /*
18  * Converts direct items to an unformatted node. Panics if file has no
19  * tail. -ENOSPC if no disk space for conversion
20  */
21 /*
22  * path points to first direct item of the file regardless of how many of
23  * them are there
24  */
25 int direct2indirect(struct reiserfs_transaction_handle *th, struct inode *inode,
26 		    struct treepath *path, struct buffer_head *unbh,
27 		    loff_t tail_offset)
28 {
29 	struct super_block *sb = inode->i_sb;
30 	struct buffer_head *up_to_date_bh;
31 	struct item_head *p_le_ih = tp_item_head(path);
32 	unsigned long total_tail = 0;
33 
34 	/* Key to search for the last byte of the converted item. */
35 	struct cpu_key end_key;
36 
37 	/*
38 	 * new indirect item to be inserted or key
39 	 * of unfm pointer to be pasted
40 	 */
41 	struct item_head ind_ih;
42 	int blk_size;
43 	/* returned value for reiserfs_insert_item and clones */
44 	int  retval;
45 	/* Handle on an unformatted node that will be inserted in the tree. */
46 	unp_t unfm_ptr;
47 
48 	BUG_ON(!th->t_trans_id);
49 
50 	REISERFS_SB(sb)->s_direct2indirect++;
51 
52 	blk_size = sb->s_blocksize;
53 
54 	/*
55 	 * and key to search for append or insert pointer to the new
56 	 * unformatted node.
57 	 */
58 	copy_item_head(&ind_ih, p_le_ih);
59 	set_le_ih_k_offset(&ind_ih, tail_offset);
60 	set_le_ih_k_type(&ind_ih, TYPE_INDIRECT);
61 
62 	/* Set the key to search for the place for new unfm pointer */
63 	make_cpu_key(&end_key, inode, tail_offset, TYPE_INDIRECT, 4);
64 
65 	/* FIXME: we could avoid this */
66 	if (search_for_position_by_key(sb, &end_key, path) == POSITION_FOUND) {
67 		reiserfs_error(sb, "PAP-14030",
68 			       "pasted or inserted byte exists in "
69 			       "the tree %K. Use fsck to repair.", &end_key);
70 		pathrelse(path);
71 		return -EIO;
72 	}
73 
74 	p_le_ih = tp_item_head(path);
75 
76 	unfm_ptr = cpu_to_le32(unbh->b_blocknr);
77 
78 	if (is_statdata_le_ih(p_le_ih)) {
79 		/* Insert new indirect item. */
80 		set_ih_free_space(&ind_ih, 0);	/* delete at nearest future */
81 		put_ih_item_len(&ind_ih, UNFM_P_SIZE);
82 		PATH_LAST_POSITION(path)++;
83 		retval =
84 		    reiserfs_insert_item(th, path, &end_key, &ind_ih, inode,
85 					 (char *)&unfm_ptr);
86 	} else {
87 		/* Paste into last indirect item of an object. */
88 		retval = reiserfs_paste_into_item(th, path, &end_key, inode,
89 						    (char *)&unfm_ptr,
90 						    UNFM_P_SIZE);
91 	}
92 	if (retval) {
93 		return retval;
94 	}
95 	/*
96 	 * note: from here there are two keys which have matching first
97 	 *  three key components. They only differ by the fourth one.
98 	 */
99 
100 	/* Set the key to search for the direct items of the file */
101 	make_cpu_key(&end_key, inode, max_reiserfs_offset(inode), TYPE_DIRECT,
102 		     4);
103 
104 	/*
105 	 * Move bytes from the direct items to the new unformatted node
106 	 * and delete them.
107 	 */
108 	while (1) {
109 		int tail_size;
110 
111 		/*
112 		 * end_key.k_offset is set so, that we will always have found
113 		 * last item of the file
114 		 */
115 		if (search_for_position_by_key(sb, &end_key, path) ==
116 		    POSITION_FOUND)
117 			reiserfs_panic(sb, "PAP-14050",
118 				       "direct item (%K) not found", &end_key);
119 		p_le_ih = tp_item_head(path);
120 		RFALSE(!is_direct_le_ih(p_le_ih),
121 		       "vs-14055: direct item expected(%K), found %h",
122 		       &end_key, p_le_ih);
123 		tail_size = (le_ih_k_offset(p_le_ih) & (blk_size - 1))
124 		    + ih_item_len(p_le_ih) - 1;
125 
126 		/*
127 		 * we only send the unbh pointer if the buffer is not
128 		 * up to date.  this avoids overwriting good data from
129 		 * writepage() with old data from the disk or buffer cache
130 		 * Special case: unbh->b_page will be NULL if we are coming
131 		 * through DIRECT_IO handler here.
132 		 */
133 		if (!unbh->b_page || buffer_uptodate(unbh)
134 		    || PageUptodate(unbh->b_page)) {
135 			up_to_date_bh = NULL;
136 		} else {
137 			up_to_date_bh = unbh;
138 		}
139 		retval = reiserfs_delete_item(th, path, &end_key, inode,
140 						up_to_date_bh);
141 
142 		total_tail += retval;
143 
144 		/* done: file does not have direct items anymore */
145 		if (tail_size == retval)
146 			break;
147 
148 	}
149 	/*
150 	 * if we've copied bytes from disk into the page, we need to zero
151 	 * out the unused part of the block (it was not up to date before)
152 	 */
153 	if (up_to_date_bh) {
154 		unsigned pgoff =
155 		    (tail_offset + total_tail - 1) & (PAGE_SIZE - 1);
156 		char *kaddr = kmap_atomic(up_to_date_bh->b_page);
157 		memset(kaddr + pgoff, 0, blk_size - total_tail);
158 		kunmap_atomic(kaddr);
159 	}
160 
161 	REISERFS_I(inode)->i_first_direct_byte = U32_MAX;
162 
163 	return 0;
164 }
165 
166 /* stolen from fs/buffer.c */
167 void reiserfs_unmap_buffer(struct buffer_head *bh)
168 {
169 	lock_buffer(bh);
170 	if (buffer_journaled(bh) || buffer_journal_dirty(bh)) {
171 		BUG();
172 	}
173 	clear_buffer_dirty(bh);
174 	/*
175 	 * Remove the buffer from whatever list it belongs to. We are mostly
176 	 * interested in removing it from per-sb j_dirty_buffers list, to avoid
177 	 * BUG() on attempt to write not mapped buffer
178 	 */
179 	if ((!list_empty(&bh->b_assoc_buffers) || bh->b_private) && bh->b_page) {
180 		struct inode *inode = bh->b_page->mapping->host;
181 		struct reiserfs_journal *j = SB_JOURNAL(inode->i_sb);
182 		spin_lock(&j->j_dirty_buffers_lock);
183 		list_del_init(&bh->b_assoc_buffers);
184 		reiserfs_free_jh(bh);
185 		spin_unlock(&j->j_dirty_buffers_lock);
186 	}
187 	clear_buffer_mapped(bh);
188 	clear_buffer_req(bh);
189 	clear_buffer_new(bh);
190 	bh->b_bdev = NULL;
191 	unlock_buffer(bh);
192 }
193 
194 /*
195  * this first locks inode (neither reads nor sync are permitted),
196  * reads tail through page cache, insert direct item. When direct item
197  * inserted successfully inode is left locked. Return value is always
198  * what we expect from it (number of cut bytes). But when tail remains
199  * in the unformatted node, we set mode to SKIP_BALANCING and unlock
200  * inode
201  */
202 int indirect2direct(struct reiserfs_transaction_handle *th,
203 		    struct inode *inode, struct page *page,
204 		    struct treepath *path,	/* path to the indirect item. */
205 		    const struct cpu_key *item_key,	/* Key to look for
206 							 * unformatted node
207 							 * pointer to be cut. */
208 		    loff_t n_new_file_size,	/* New file size. */
209 		    char *mode)
210 {
211 	struct super_block *sb = inode->i_sb;
212 	struct item_head s_ih;
213 	unsigned long block_size = sb->s_blocksize;
214 	char *tail;
215 	int tail_len, round_tail_len;
216 	loff_t pos, pos1;	/* position of first byte of the tail */
217 	struct cpu_key key;
218 
219 	BUG_ON(!th->t_trans_id);
220 
221 	REISERFS_SB(sb)->s_indirect2direct++;
222 
223 	*mode = M_SKIP_BALANCING;
224 
225 	/* store item head path points to. */
226 	copy_item_head(&s_ih, tp_item_head(path));
227 
228 	tail_len = (n_new_file_size & (block_size - 1));
229 	if (get_inode_sd_version(inode) == STAT_DATA_V2)
230 		round_tail_len = ROUND_UP(tail_len);
231 	else
232 		round_tail_len = tail_len;
233 
234 	pos =
235 	    le_ih_k_offset(&s_ih) - 1 + (ih_item_len(&s_ih) / UNFM_P_SIZE -
236 					 1) * sb->s_blocksize;
237 	pos1 = pos;
238 
239 	/*
240 	 * we are protected by i_mutex. The tail can not disapper, not
241 	 * append can be done either
242 	 * we are in truncate or packing tail in file_release
243 	 */
244 
245 	tail = (char *)kmap(page);	/* this can schedule */
246 
247 	if (path_changed(&s_ih, path)) {
248 		/* re-search indirect item */
249 		if (search_for_position_by_key(sb, item_key, path)
250 		    == POSITION_NOT_FOUND)
251 			reiserfs_panic(sb, "PAP-5520",
252 				       "item to be converted %K does not exist",
253 				       item_key);
254 		copy_item_head(&s_ih, tp_item_head(path));
255 #ifdef CONFIG_REISERFS_CHECK
256 		pos = le_ih_k_offset(&s_ih) - 1 +
257 		    (ih_item_len(&s_ih) / UNFM_P_SIZE -
258 		     1) * sb->s_blocksize;
259 		if (pos != pos1)
260 			reiserfs_panic(sb, "vs-5530", "tail position "
261 				       "changed while we were reading it");
262 #endif
263 	}
264 
265 	/* Set direct item header to insert. */
266 	make_le_item_head(&s_ih, NULL, get_inode_item_key_version(inode),
267 			  pos1 + 1, TYPE_DIRECT, round_tail_len,
268 			  0xffff /*ih_free_space */ );
269 
270 	/*
271 	 * we want a pointer to the first byte of the tail in the page.
272 	 * the page was locked and this part of the page was up to date when
273 	 * indirect2direct was called, so we know the bytes are still valid
274 	 */
275 	tail = tail + (pos & (PAGE_SIZE - 1));
276 
277 	PATH_LAST_POSITION(path)++;
278 
279 	key = *item_key;
280 	set_cpu_key_k_type(&key, TYPE_DIRECT);
281 	key.key_length = 4;
282 	/* Insert tail as new direct item in the tree */
283 	if (reiserfs_insert_item(th, path, &key, &s_ih, inode,
284 				 tail ? tail : NULL) < 0) {
285 		/*
286 		 * No disk memory. So we can not convert last unformatted node
287 		 * to the direct item.  In this case we used to adjust
288 		 * indirect items's ih_free_space. Now ih_free_space is not
289 		 * used, it would be ideal to write zeros to corresponding
290 		 * unformatted node. For now i_size is considered as guard for
291 		 * going out of file size
292 		 */
293 		kunmap(page);
294 		return block_size - round_tail_len;
295 	}
296 	kunmap(page);
297 
298 	/* make sure to get the i_blocks changes from reiserfs_insert_item */
299 	reiserfs_update_sd(th, inode);
300 
301 	/*
302 	 * note: we have now the same as in above direct2indirect
303 	 * conversion: there are two keys which have matching first three
304 	 * key components. They only differ by the fourth one.
305 	 */
306 
307 	/*
308 	 * We have inserted new direct item and must remove last
309 	 * unformatted node.
310 	 */
311 	*mode = M_CUT;
312 
313 	/* we store position of first direct item in the in-core inode */
314 	/* mark_file_with_tail (inode, pos1 + 1); */
315 	REISERFS_I(inode)->i_first_direct_byte = pos1 + 1;
316 
317 	return block_size - round_tail_len;
318 }
319