fs: take the ACL checks to common code
[linux-2.6.git] / fs / reiserfs / tail_conversion.c
1 /*
2  * Copyright 1999 Hans Reiser, see reiserfs/README for licensing and copyright details
3  */
4
5 #include <linux/time.h>
6 #include <linux/pagemap.h>
7 #include <linux/buffer_head.h>
8 #include <linux/reiserfs_fs.h>
9
10 /* access to tail : when one is going to read tail it must make sure, that is not running.
11  direct2indirect and indirect2direct can not run concurrently */
12
13 /* Converts direct items to an unformatted node. Panics if file has no
14    tail. -ENOSPC if no disk space for conversion */
15 /* path points to first direct item of the file regarless of how many of
16    them are there */
17 int direct2indirect(struct reiserfs_transaction_handle *th, struct inode *inode,
18                     struct treepath *path, struct buffer_head *unbh,
19                     loff_t tail_offset)
20 {
21         struct super_block *sb = inode->i_sb;
22         struct buffer_head *up_to_date_bh;
23         struct item_head *p_le_ih = PATH_PITEM_HEAD(path);
24         unsigned long total_tail = 0;
25         struct cpu_key end_key; /* Key to search for the last byte of the
26                                    converted item. */
27         struct item_head ind_ih;        /* new indirect item to be inserted or
28                                            key of unfm pointer to be pasted */
29         int blk_size, retval;   /* returned value for reiserfs_insert_item and clones */
30         unp_t unfm_ptr;         /* Handle on an unformatted node
31                                    that will be inserted in the
32                                    tree. */
33
34         BUG_ON(!th->t_trans_id);
35
36         REISERFS_SB(sb)->s_direct2indirect++;
37
38         blk_size = sb->s_blocksize;
39
40         /* and key to search for append or insert pointer to the new
41            unformatted node. */
42         copy_item_head(&ind_ih, p_le_ih);
43         set_le_ih_k_offset(&ind_ih, tail_offset);
44         set_le_ih_k_type(&ind_ih, TYPE_INDIRECT);
45
46         /* Set the key to search for the place for new unfm pointer */
47         make_cpu_key(&end_key, inode, tail_offset, TYPE_INDIRECT, 4);
48
49         /* FIXME: we could avoid this */
50         if (search_for_position_by_key(sb, &end_key, path) == POSITION_FOUND) {
51                 reiserfs_error(sb, "PAP-14030",
52                                "pasted or inserted byte exists in "
53                                "the tree %K. Use fsck to repair.", &end_key);
54                 pathrelse(path);
55                 return -EIO;
56         }
57
58         p_le_ih = PATH_PITEM_HEAD(path);
59
60         unfm_ptr = cpu_to_le32(unbh->b_blocknr);
61
62         if (is_statdata_le_ih(p_le_ih)) {
63                 /* Insert new indirect item. */
64                 set_ih_free_space(&ind_ih, 0);  /* delete at nearest future */
65                 put_ih_item_len(&ind_ih, UNFM_P_SIZE);
66                 PATH_LAST_POSITION(path)++;
67                 retval =
68                     reiserfs_insert_item(th, path, &end_key, &ind_ih, inode,
69                                          (char *)&unfm_ptr);
70         } else {
71                 /* Paste into last indirect item of an object. */
72                 retval = reiserfs_paste_into_item(th, path, &end_key, inode,
73                                                     (char *)&unfm_ptr,
74                                                     UNFM_P_SIZE);
75         }
76         if (retval) {
77                 return retval;
78         }
79         // note: from here there are two keys which have matching first
80         // three key components. They only differ by the fourth one.
81
82         /* Set the key to search for the direct items of the file */
83         make_cpu_key(&end_key, inode, max_reiserfs_offset(inode), TYPE_DIRECT,
84                      4);
85
86         /* Move bytes from the direct items to the new unformatted node
87            and delete them. */
88         while (1) {
89                 int tail_size;
90
91                 /* end_key.k_offset is set so, that we will always have found
92                    last item of the file */
93                 if (search_for_position_by_key(sb, &end_key, path) ==
94                     POSITION_FOUND)
95                         reiserfs_panic(sb, "PAP-14050",
96                                        "direct item (%K) not found", &end_key);
97                 p_le_ih = PATH_PITEM_HEAD(path);
98                 RFALSE(!is_direct_le_ih(p_le_ih),
99                        "vs-14055: direct item expected(%K), found %h",
100                        &end_key, p_le_ih);
101                 tail_size = (le_ih_k_offset(p_le_ih) & (blk_size - 1))
102                     + ih_item_len(p_le_ih) - 1;
103
104                 /* we only send the unbh pointer if the buffer is not up to date.
105                  ** this avoids overwriting good data from writepage() with old data
106                  ** from the disk or buffer cache
107                  ** Special case: unbh->b_page will be NULL if we are coming through
108                  ** DIRECT_IO handler here.
109                  */
110                 if (!unbh->b_page || buffer_uptodate(unbh)
111                     || PageUptodate(unbh->b_page)) {
112                         up_to_date_bh = NULL;
113                 } else {
114                         up_to_date_bh = unbh;
115                 }
116                 retval = reiserfs_delete_item(th, path, &end_key, inode,
117                                                 up_to_date_bh);
118
119                 total_tail += retval;
120                 if (tail_size == 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 =
130                     (tail_offset + total_tail - 1) & (PAGE_CACHE_SIZE - 1);
131                 char *kaddr = kmap_atomic(up_to_date_bh->b_page, KM_USER0);
132                 memset(kaddr + pgoff, 0, blk_size - total_tail);
133                 kunmap_atomic(kaddr, KM_USER0);
134         }
135
136         REISERFS_I(inode)->i_first_direct_byte = U32_MAX;
137
138         return 0;
139 }
140
141 /* stolen from fs/buffer.c */
142 void reiserfs_unmap_buffer(struct buffer_head *bh)
143 {
144         lock_buffer(bh);
145         if (buffer_journaled(bh) || buffer_journal_dirty(bh)) {
146                 BUG();
147         }
148         clear_buffer_dirty(bh);
149         /* Remove the buffer from whatever list it belongs to. We are mostly
150            interested in removing it from per-sb j_dirty_buffers list, to avoid
151            BUG() on attempt to write not mapped buffer */
152         if ((!list_empty(&bh->b_assoc_buffers) || bh->b_private) && bh->b_page) {
153                 struct inode *inode = bh->b_page->mapping->host;
154                 struct reiserfs_journal *j = SB_JOURNAL(inode->i_sb);
155                 spin_lock(&j->j_dirty_buffers_lock);
156                 list_del_init(&bh->b_assoc_buffers);
157                 reiserfs_free_jh(bh);
158                 spin_unlock(&j->j_dirty_buffers_lock);
159         }
160         clear_buffer_mapped(bh);
161         clear_buffer_req(bh);
162         clear_buffer_new(bh);
163         bh->b_bdev = NULL;
164         unlock_buffer(bh);
165 }
166
167 /* this first locks inode (neither reads nor sync are permitted),
168    reads tail through page cache, insert direct item. When direct item
169    inserted successfully inode is left locked. Return value is always
170    what we expect from it (number of cut bytes). But when tail remains
171    in the unformatted node, we set mode to SKIP_BALANCING and unlock
172    inode */
173 int indirect2direct(struct reiserfs_transaction_handle *th,
174                     struct inode *inode, struct page *page,
175                     struct treepath *path,      /* path to the indirect item. */
176                     const struct cpu_key *item_key,     /* Key to look for
177                                                          * unformatted node
178                                                          * pointer to be cut. */
179                     loff_t n_new_file_size,     /* New file size. */
180                     char *mode)
181 {
182         struct super_block *sb = inode->i_sb;
183         struct item_head s_ih;
184         unsigned long block_size = sb->s_blocksize;
185         char *tail;
186         int tail_len, round_tail_len;
187         loff_t pos, pos1;       /* position of first byte of the tail */
188         struct cpu_key key;
189
190         BUG_ON(!th->t_trans_id);
191
192         REISERFS_SB(sb)->s_indirect2direct++;
193
194         *mode = M_SKIP_BALANCING;
195
196         /* store item head path points to. */
197         copy_item_head(&s_ih, PATH_PITEM_HEAD(path));
198
199         tail_len = (n_new_file_size & (block_size - 1));
200         if (get_inode_sd_version(inode) == STAT_DATA_V2)
201                 round_tail_len = ROUND_UP(tail_len);
202         else
203                 round_tail_len = tail_len;
204
205         pos =
206             le_ih_k_offset(&s_ih) - 1 + (ih_item_len(&s_ih) / UNFM_P_SIZE -
207                                          1) * sb->s_blocksize;
208         pos1 = pos;
209
210         // we are protected by i_mutex. The tail can not disapper, not
211         // append can be done either
212         // we are in truncate or packing tail in file_release
213
214         tail = (char *)kmap(page);      /* this can schedule */
215
216         if (path_changed(&s_ih, path)) {
217                 /* re-search indirect item */
218                 if (search_for_position_by_key(sb, item_key, path)
219                     == POSITION_NOT_FOUND)
220                         reiserfs_panic(sb, "PAP-5520",
221                                        "item to be converted %K does not exist",
222                                        item_key);
223                 copy_item_head(&s_ih, PATH_PITEM_HEAD(path));
224 #ifdef CONFIG_REISERFS_CHECK
225                 pos = le_ih_k_offset(&s_ih) - 1 +
226                     (ih_item_len(&s_ih) / UNFM_P_SIZE -
227                      1) * sb->s_blocksize;
228                 if (pos != pos1)
229                         reiserfs_panic(sb, "vs-5530", "tail position "
230                                        "changed while we were reading it");
231 #endif
232         }
233
234         /* Set direct item header to insert. */
235         make_le_item_head(&s_ih, NULL, get_inode_item_key_version(inode),
236                           pos1 + 1, TYPE_DIRECT, round_tail_len,
237                           0xffff /*ih_free_space */ );
238
239         /* we want a pointer to the first byte of the tail in the page.
240          ** the page was locked and this part of the page was up to date when
241          ** indirect2direct was called, so we know the bytes are still valid
242          */
243         tail = tail + (pos & (PAGE_CACHE_SIZE - 1));
244
245         PATH_LAST_POSITION(path)++;
246
247         key = *item_key;
248         set_cpu_key_k_type(&key, TYPE_DIRECT);
249         key.key_length = 4;
250         /* Insert tail as new direct item in the tree */
251         if (reiserfs_insert_item(th, path, &key, &s_ih, inode,
252                                  tail ? tail : NULL) < 0) {
253                 /* No disk memory. So we can not convert last unformatted node
254                    to the direct item.  In this case we used to adjust
255                    indirect items's ih_free_space. Now ih_free_space is not
256                    used, it would be ideal to write zeros to corresponding
257                    unformatted node. For now i_size is considered as guard for
258                    going out of file size */
259                 kunmap(page);
260                 return block_size - round_tail_len;
261         }
262         kunmap(page);
263
264         /* make sure to get the i_blocks changes from reiserfs_insert_item */
265         reiserfs_update_sd(th, inode);
266
267         // note: we have now the same as in above direct2indirect
268         // conversion: there are two keys which have matching first three
269         // key components. They only differ by the fouhth one.
270
271         /* We have inserted new direct item and must remove last
272            unformatted node. */
273         *mode = M_CUT;
274
275         /* we store position of first direct item in the in-core inode */
276         /* mark_file_with_tail (inode, pos1 + 1); */
277         REISERFS_I(inode)->i_first_direct_byte = pos1 + 1;
278
279         return block_size - round_tail_len;
280 }