ufs: ensure fast symlinks are NUL-terminated
[linux-2.6.git] / fs / ufs / util.c
1 /*
2  *  linux/fs/ufs/util.c
3  *
4  * Copyright (C) 1998
5  * Daniel Pirkl <daniel.pirkl@email.cz>
6  * Charles University, Faculty of Mathematics and Physics
7  */
8  
9 #include <linux/string.h>
10 #include <linux/slab.h>
11 #include <linux/buffer_head.h>
12
13 #include "ufs_fs.h"
14 #include "ufs.h"
15 #include "swab.h"
16 #include "util.h"
17
18 struct ufs_buffer_head * _ubh_bread_ (struct ufs_sb_private_info * uspi,
19         struct super_block *sb, u64 fragment, u64 size)
20 {
21         struct ufs_buffer_head * ubh;
22         unsigned i, j ;
23         u64  count = 0;
24         if (size & ~uspi->s_fmask)
25                 return NULL;
26         count = size >> uspi->s_fshift;
27         if (count > UFS_MAXFRAG)
28                 return NULL;
29         ubh = (struct ufs_buffer_head *)
30                 kmalloc (sizeof (struct ufs_buffer_head), GFP_KERNEL);
31         if (!ubh)
32                 return NULL;
33         ubh->fragment = fragment;
34         ubh->count = count;
35         for (i = 0; i < count; i++)
36                 if (!(ubh->bh[i] = sb_bread(sb, fragment + i)))
37                         goto failed;
38         for (; i < UFS_MAXFRAG; i++)
39                 ubh->bh[i] = NULL;
40         return ubh;
41 failed:
42         for (j = 0; j < i; j++)
43                 brelse (ubh->bh[j]);
44         kfree(ubh);
45         return NULL;
46 }
47
48 struct ufs_buffer_head * ubh_bread_uspi (struct ufs_sb_private_info * uspi,
49         struct super_block *sb, u64 fragment, u64 size)
50 {
51         unsigned i, j;
52         u64 count = 0;
53         if (size & ~uspi->s_fmask)
54                 return NULL;
55         count = size >> uspi->s_fshift;
56         if (count <= 0 || count > UFS_MAXFRAG)
57                 return NULL;
58         USPI_UBH(uspi)->fragment = fragment;
59         USPI_UBH(uspi)->count = count;
60         for (i = 0; i < count; i++)
61                 if (!(USPI_UBH(uspi)->bh[i] = sb_bread(sb, fragment + i)))
62                         goto failed;
63         for (; i < UFS_MAXFRAG; i++)
64                 USPI_UBH(uspi)->bh[i] = NULL;
65         return USPI_UBH(uspi);
66 failed:
67         for (j = 0; j < i; j++)
68                 brelse (USPI_UBH(uspi)->bh[j]);
69         return NULL;
70 }
71
72 void ubh_brelse (struct ufs_buffer_head * ubh)
73 {
74         unsigned i;
75         if (!ubh)
76                 return;
77         for (i = 0; i < ubh->count; i++)
78                 brelse (ubh->bh[i]);
79         kfree (ubh);
80 }
81
82 void ubh_brelse_uspi (struct ufs_sb_private_info * uspi)
83 {
84         unsigned i;
85         if (!USPI_UBH(uspi))
86                 return;
87         for ( i = 0; i < USPI_UBH(uspi)->count; i++ ) {
88                 brelse (USPI_UBH(uspi)->bh[i]);
89                 USPI_UBH(uspi)->bh[i] = NULL;
90         }
91 }
92
93 void ubh_mark_buffer_dirty (struct ufs_buffer_head * ubh)
94 {
95         unsigned i;
96         if (!ubh)
97                 return;
98         for ( i = 0; i < ubh->count; i++ )
99                 mark_buffer_dirty (ubh->bh[i]);
100 }
101
102 void ubh_mark_buffer_uptodate (struct ufs_buffer_head * ubh, int flag)
103 {
104         unsigned i;
105         if (!ubh)
106                 return;
107         if (flag) {
108                 for ( i = 0; i < ubh->count; i++ )
109                         set_buffer_uptodate (ubh->bh[i]);
110         } else {
111                 for ( i = 0; i < ubh->count; i++ )
112                         clear_buffer_uptodate (ubh->bh[i]);
113         }
114 }
115
116 void ubh_ll_rw_block(int rw, struct ufs_buffer_head *ubh)
117 {
118         if (!ubh)
119                 return;
120
121         ll_rw_block(rw, ubh->count, ubh->bh);
122 }
123
124 void ubh_wait_on_buffer (struct ufs_buffer_head * ubh)
125 {
126         unsigned i;
127         if (!ubh)
128                 return;
129         for ( i = 0; i < ubh->count; i++ )
130                 wait_on_buffer (ubh->bh[i]);
131 }
132
133 void ubh_bforget (struct ufs_buffer_head * ubh)
134 {
135         unsigned i;
136         if (!ubh) 
137                 return;
138         for ( i = 0; i < ubh->count; i++ ) if ( ubh->bh[i] ) 
139                 bforget (ubh->bh[i]);
140 }
141  
142 int ubh_buffer_dirty (struct ufs_buffer_head * ubh)
143 {
144         unsigned i;
145         unsigned result = 0;
146         if (!ubh)
147                 return 0;
148         for ( i = 0; i < ubh->count; i++ )
149                 result |= buffer_dirty(ubh->bh[i]);
150         return result;
151 }
152
153 void _ubh_ubhcpymem_(struct ufs_sb_private_info * uspi, 
154         unsigned char * mem, struct ufs_buffer_head * ubh, unsigned size)
155 {
156         unsigned len, bhno;
157         if (size > (ubh->count << uspi->s_fshift))
158                 size = ubh->count << uspi->s_fshift;
159         bhno = 0;
160         while (size) {
161                 len = min_t(unsigned int, size, uspi->s_fsize);
162                 memcpy (mem, ubh->bh[bhno]->b_data, len);
163                 mem += uspi->s_fsize;
164                 size -= len;
165                 bhno++;
166         }
167 }
168
169 void _ubh_memcpyubh_(struct ufs_sb_private_info * uspi, 
170         struct ufs_buffer_head * ubh, unsigned char * mem, unsigned size)
171 {
172         unsigned len, bhno;
173         if (size > (ubh->count << uspi->s_fshift))
174                 size = ubh->count << uspi->s_fshift;
175         bhno = 0;
176         while (size) {
177                 len = min_t(unsigned int, size, uspi->s_fsize);
178                 memcpy (ubh->bh[bhno]->b_data, mem, len);
179                 mem += uspi->s_fsize;
180                 size -= len;
181                 bhno++;
182         }
183 }
184
185 dev_t
186 ufs_get_inode_dev(struct super_block *sb, struct ufs_inode_info *ufsi)
187 {
188         __u32 fs32;
189         dev_t dev;
190
191         if ((UFS_SB(sb)->s_flags & UFS_ST_MASK) == UFS_ST_SUNx86)
192                 fs32 = fs32_to_cpu(sb, ufsi->i_u1.i_data[1]);
193         else
194                 fs32 = fs32_to_cpu(sb, ufsi->i_u1.i_data[0]);
195         switch (UFS_SB(sb)->s_flags & UFS_ST_MASK) {
196         case UFS_ST_SUNx86:
197         case UFS_ST_SUN:
198                 if ((fs32 & 0xffff0000) == 0 ||
199                     (fs32 & 0xffff0000) == 0xffff0000)
200                         dev = old_decode_dev(fs32 & 0x7fff);
201                 else
202                         dev = MKDEV(sysv_major(fs32), sysv_minor(fs32));
203                 break;
204
205         default:
206                 dev = old_decode_dev(fs32);
207                 break;
208         }
209         return dev;
210 }
211
212 void
213 ufs_set_inode_dev(struct super_block *sb, struct ufs_inode_info *ufsi, dev_t dev)
214 {
215         __u32 fs32;
216
217         switch (UFS_SB(sb)->s_flags & UFS_ST_MASK) {
218         case UFS_ST_SUNx86:
219         case UFS_ST_SUN:
220                 fs32 = sysv_encode_dev(dev);
221                 if ((fs32 & 0xffff8000) == 0) {
222                         fs32 = old_encode_dev(dev);
223                 }
224                 break;
225
226         default:
227                 fs32 = old_encode_dev(dev);
228                 break;
229         }
230         if ((UFS_SB(sb)->s_flags & UFS_ST_MASK) == UFS_ST_SUNx86)
231                 ufsi->i_u1.i_data[1] = cpu_to_fs32(sb, fs32);
232         else
233                 ufsi->i_u1.i_data[0] = cpu_to_fs32(sb, fs32);
234 }
235
236 /**
237  * ufs_get_locked_page() - locate, pin and lock a pagecache page, if not exist
238  * read it from disk.
239  * @mapping: the address_space to search
240  * @index: the page index
241  *
242  * Locates the desired pagecache page, if not exist we'll read it,
243  * locks it, increments its reference
244  * count and returns its address.
245  *
246  */
247
248 struct page *ufs_get_locked_page(struct address_space *mapping,
249                                  pgoff_t index)
250 {
251         struct page *page;
252
253         page = find_lock_page(mapping, index);
254         if (!page) {
255                 page = read_mapping_page(mapping, index, NULL);
256
257                 if (IS_ERR(page)) {
258                         printk(KERN_ERR "ufs_change_blocknr: "
259                                "read_mapping_page error: ino %lu, index: %lu\n",
260                                mapping->host->i_ino, index);
261                         goto out;
262                 }
263
264                 lock_page(page);
265
266                 if (unlikely(page->mapping == NULL)) {
267                         /* Truncate got there first */
268                         unlock_page(page);
269                         page_cache_release(page);
270                         page = NULL;
271                         goto out;
272                 }
273
274                 if (!PageUptodate(page) || PageError(page)) {
275                         unlock_page(page);
276                         page_cache_release(page);
277
278                         printk(KERN_ERR "ufs_change_blocknr: "
279                                "can not read page: ino %lu, index: %lu\n",
280                                mapping->host->i_ino, index);
281
282                         page = ERR_PTR(-EIO);
283                 }
284         }
285 out:
286         return page;
287 }