[JFFS2] Add support for write-buffer verification.
[linux-2.6] / fs / udf / dir.c
1 /*
2  * dir.c
3  *
4  * PURPOSE
5  *  Directory handling routines for the OSTA-UDF(tm) filesystem.
6  *
7  * COPYRIGHT
8  *      This file is distributed under the terms of the GNU General Public
9  *      License (GPL). Copies of the GPL can be obtained from:
10  *              ftp://prep.ai.mit.edu/pub/gnu/GPL
11  *      Each contributing author retains all rights to their own work.
12  *
13  *  (C) 1998-2004 Ben Fennema
14  *
15  * HISTORY
16  *
17  *  10/05/98 dgb  Split directory operations into its own file
18  *                Implemented directory reads via do_udf_readdir
19  *  10/06/98      Made directory operations work!
20  *  11/17/98      Rewrote directory to support ICBTAG_FLAG_AD_LONG
21  *  11/25/98 blf  Rewrote directory handling (readdir+lookup) to support reading
22  *                across blocks.
23  *  12/12/98      Split out the lookup code to namei.c. bulk of directory
24  *                code now in directory.c:udf_fileident_read.
25  */
26
27 #include "udfdecl.h"
28
29 #include <linux/string.h>
30 #include <linux/errno.h>
31 #include <linux/mm.h>
32 #include <linux/slab.h>
33 #include <linux/smp_lock.h>
34 #include <linux/buffer_head.h>
35
36 #include "udf_i.h"
37 #include "udf_sb.h"
38
39 /* Prototypes for file operations */
40 static int udf_readdir(struct file *, void *, filldir_t);
41 static int do_udf_readdir(struct inode *, struct file *, filldir_t, void *);
42
43 /* readdir and lookup functions */
44
45 const struct file_operations udf_dir_operations = {
46         .read                   = generic_read_dir,
47         .readdir                = udf_readdir,
48         .ioctl                  = udf_ioctl,
49         .fsync                  = udf_fsync_file,
50 };
51
52 /*
53  * udf_readdir
54  *
55  * PURPOSE
56  *      Read a directory entry.
57  *
58  * DESCRIPTION
59  *      Optional - sys_getdents() will return -ENOTDIR if this routine is not
60  *      available.
61  *
62  *      Refer to sys_getdents() in fs/readdir.c
63  *      sys_getdents() -> .
64  *
65  * PRE-CONDITIONS
66  *      filp                    Pointer to directory file.
67  *      buf                     Pointer to directory entry buffer.
68  *      filldir                 Pointer to filldir function.
69  *
70  * POST-CONDITIONS
71  *      <return>                >=0 on success.
72  *
73  * HISTORY
74  *      July 1, 1997 - Andrew E. Mileski
75  *      Written, tested, and released.
76  */
77
78 int udf_readdir(struct file *filp, void *dirent, filldir_t filldir)
79 {
80         struct inode *dir = filp->f_path.dentry->d_inode;
81         int result;
82
83         lock_kernel();
84
85         if ( filp->f_pos == 0 ) 
86         {
87                 if (filldir(dirent, ".", 1, filp->f_pos, dir->i_ino, DT_DIR) < 0)
88                 {
89                         unlock_kernel();
90                         return 0;
91                 }
92                 filp->f_pos ++;
93         }
94
95         result = do_udf_readdir(dir, filp, filldir, dirent);
96         unlock_kernel();
97         return result;
98 }
99
100 static int 
101 do_udf_readdir(struct inode * dir, struct file *filp, filldir_t filldir, void *dirent)
102 {
103         struct udf_fileident_bh fibh;
104         struct fileIdentDesc *fi=NULL;
105         struct fileIdentDesc cfi;
106         int block, iblock;
107         loff_t nf_pos = filp->f_pos - 1;
108         int flen;
109         char fname[UDF_NAME_LEN];
110         char *nameptr;
111         uint16_t liu;
112         uint8_t lfi;
113         loff_t size = (udf_ext0_offset(dir) + dir->i_size) >> 2;
114         struct buffer_head *tmp, *bha[16];
115         kernel_lb_addr eloc;
116         uint32_t elen;
117         sector_t offset;
118         int i, num;
119         unsigned int dt_type;
120         struct extent_position epos = { NULL, 0, {0, 0}};
121
122         if (nf_pos >= size)
123                 return 0;
124
125         if (nf_pos == 0)
126                 nf_pos = (udf_ext0_offset(dir) >> 2);
127
128         fibh.soffset = fibh.eoffset = (nf_pos & ((dir->i_sb->s_blocksize - 1) >> 2)) << 2;
129         if (UDF_I_ALLOCTYPE(dir) == ICBTAG_FLAG_AD_IN_ICB)
130                 fibh.sbh = fibh.ebh = NULL;
131         else if (inode_bmap(dir, nf_pos >> (dir->i_sb->s_blocksize_bits - 2),
132                 &epos, &eloc, &elen, &offset) == (EXT_RECORDED_ALLOCATED >> 30))
133         {
134                 block = udf_get_lb_pblock(dir->i_sb, eloc, offset);
135                 if ((++offset << dir->i_sb->s_blocksize_bits) < elen)
136                 {
137                         if (UDF_I_ALLOCTYPE(dir) == ICBTAG_FLAG_AD_SHORT)
138                                 epos.offset -= sizeof(short_ad);
139                         else if (UDF_I_ALLOCTYPE(dir) == ICBTAG_FLAG_AD_LONG)
140                                 epos.offset -= sizeof(long_ad);
141                 }
142                 else
143                         offset = 0;
144
145                 if (!(fibh.sbh = fibh.ebh = udf_tread(dir->i_sb, block)))
146                 {
147                         brelse(epos.bh);
148                         return -EIO;
149                 }
150         
151                 if (!(offset & ((16 >> (dir->i_sb->s_blocksize_bits - 9))-1)))
152                 {
153                         i = 16 >> (dir->i_sb->s_blocksize_bits - 9);
154                         if (i+offset > (elen >> dir->i_sb->s_blocksize_bits))
155                                 i = (elen >> dir->i_sb->s_blocksize_bits)-offset;
156                         for (num=0; i>0; i--)
157                         {
158                                 block = udf_get_lb_pblock(dir->i_sb, eloc, offset+i);
159                                 tmp = udf_tgetblk(dir->i_sb, block);
160                                 if (tmp && !buffer_uptodate(tmp) && !buffer_locked(tmp))
161                                         bha[num++] = tmp;
162                                 else
163                                         brelse(tmp);
164                         }
165                         if (num)
166                         {
167                                 ll_rw_block(READA, num, bha);
168                                 for (i=0; i<num; i++)
169                                         brelse(bha[i]);
170                         }
171                 }
172         }
173         else
174         {
175                 brelse(epos.bh);
176                 return -ENOENT;
177         }
178
179         while ( nf_pos < size )
180         {
181                 filp->f_pos = nf_pos + 1;
182
183                 fi = udf_fileident_read(dir, &nf_pos, &fibh, &cfi, &epos, &eloc, &elen, &offset);
184
185                 if (!fi)
186                 {
187                         if (fibh.sbh != fibh.ebh)
188                                 brelse(fibh.ebh);
189                         brelse(fibh.sbh);
190                         brelse(epos.bh);
191                         return 0;
192                 }
193
194                 liu = le16_to_cpu(cfi.lengthOfImpUse);
195                 lfi = cfi.lengthFileIdent;
196
197                 if (fibh.sbh == fibh.ebh)
198                         nameptr = fi->fileIdent + liu;
199                 else
200                 {
201                         int poffset;    /* Unpaded ending offset */
202
203                         poffset = fibh.soffset + sizeof(struct fileIdentDesc) + liu + lfi;
204
205                         if (poffset >= lfi)
206                                 nameptr = (char *)(fibh.ebh->b_data + poffset - lfi);
207                         else
208                         {
209                                 nameptr = fname;
210                                 memcpy(nameptr, fi->fileIdent + liu, lfi - poffset);
211                                 memcpy(nameptr + lfi - poffset, fibh.ebh->b_data, poffset);
212                         }
213                 }
214
215                 if ( (cfi.fileCharacteristics & FID_FILE_CHAR_DELETED) != 0 )
216                 {
217                         if ( !UDF_QUERY_FLAG(dir->i_sb, UDF_FLAG_UNDELETE) )
218                                 continue;
219                 }
220                 
221                 if ( (cfi.fileCharacteristics & FID_FILE_CHAR_HIDDEN) != 0 )
222                 {
223                         if ( !UDF_QUERY_FLAG(dir->i_sb, UDF_FLAG_UNHIDE) )
224                                 continue;
225                 }
226
227                 if ( cfi.fileCharacteristics & FID_FILE_CHAR_PARENT )
228                 {
229                         iblock = parent_ino(filp->f_path.dentry);
230                         flen = 2;
231                         memcpy(fname, "..", flen);
232                         dt_type = DT_DIR;
233                 }
234                 else
235                 {
236                         kernel_lb_addr tloc = lelb_to_cpu(cfi.icb.extLocation);
237
238                         iblock = udf_get_lb_pblock(dir->i_sb, tloc, 0);
239                         flen = udf_get_filename(dir->i_sb, nameptr, fname, lfi);
240                         dt_type = DT_UNKNOWN;
241                 }
242
243                 if (flen)
244                 {
245                         if (filldir(dirent, fname, flen, filp->f_pos, iblock, dt_type) < 0)
246                         {
247                                 if (fibh.sbh != fibh.ebh)
248                                         brelse(fibh.ebh);
249                                 brelse(fibh.sbh);
250                                 brelse(epos.bh);
251                                 return 0;
252                         }
253                 }
254         } /* end while */
255
256         filp->f_pos = nf_pos + 1;
257
258         if (fibh.sbh != fibh.ebh)
259                 brelse(fibh.ebh);
260         brelse(fibh.sbh);
261         brelse(epos.bh);
262
263         return 0;
264 }