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[karo-tx-linux.git] / 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/bio.h>
34
35 #include "udf_i.h"
36 #include "udf_sb.h"
37
38
39 static int udf_readdir(struct file *file, struct dir_context *ctx)
40 {
41         struct inode *dir = file_inode(file);
42         struct udf_inode_info *iinfo = UDF_I(dir);
43         struct udf_fileident_bh fibh = { .sbh = NULL, .ebh = NULL};
44         struct fileIdentDesc *fi = NULL;
45         struct fileIdentDesc cfi;
46         int block, iblock;
47         loff_t nf_pos;
48         int flen;
49         unsigned char *fname = NULL, *copy_name = NULL;
50         unsigned char *nameptr;
51         uint16_t liu;
52         uint8_t lfi;
53         loff_t size = udf_ext0_offset(dir) + dir->i_size;
54         struct buffer_head *tmp, *bha[16];
55         struct kernel_lb_addr eloc;
56         uint32_t elen;
57         sector_t offset;
58         int i, num, ret = 0;
59         struct extent_position epos = { NULL, 0, {0, 0} };
60         struct super_block *sb = dir->i_sb;
61
62         if (ctx->pos == 0) {
63                 if (!dir_emit_dot(file, ctx))
64                         return 0;
65                 ctx->pos = 1;
66         }
67         nf_pos = (ctx->pos - 1) << 2;
68         if (nf_pos >= size)
69                 goto out;
70
71         fname = kmalloc(UDF_NAME_LEN, GFP_NOFS);
72         if (!fname) {
73                 ret = -ENOMEM;
74                 goto out;
75         }
76
77         if (nf_pos == 0)
78                 nf_pos = udf_ext0_offset(dir);
79
80         fibh.soffset = fibh.eoffset = nf_pos & (sb->s_blocksize - 1);
81         if (iinfo->i_alloc_type != ICBTAG_FLAG_AD_IN_ICB) {
82                 if (inode_bmap(dir, nf_pos >> sb->s_blocksize_bits,
83                     &epos, &eloc, &elen, &offset)
84                     != (EXT_RECORDED_ALLOCATED >> 30)) {
85                         ret = -ENOENT;
86                         goto out;
87                 }
88                 block = udf_get_lb_pblock(sb, &eloc, offset);
89                 if ((++offset << sb->s_blocksize_bits) < elen) {
90                         if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT)
91                                 epos.offset -= sizeof(struct short_ad);
92                         else if (iinfo->i_alloc_type ==
93                                         ICBTAG_FLAG_AD_LONG)
94                                 epos.offset -= sizeof(struct long_ad);
95                 } else {
96                         offset = 0;
97                 }
98
99                 if (!(fibh.sbh = fibh.ebh = udf_tread(sb, block))) {
100                         ret = -EIO;
101                         goto out;
102                 }
103
104                 if (!(offset & ((16 >> (sb->s_blocksize_bits - 9)) - 1))) {
105                         i = 16 >> (sb->s_blocksize_bits - 9);
106                         if (i + offset > (elen >> sb->s_blocksize_bits))
107                                 i = (elen >> sb->s_blocksize_bits) - offset;
108                         for (num = 0; i > 0; i--) {
109                                 block = udf_get_lb_pblock(sb, &eloc, offset + i);
110                                 tmp = udf_tgetblk(sb, block);
111                                 if (tmp && !buffer_uptodate(tmp) && !buffer_locked(tmp))
112                                         bha[num++] = tmp;
113                                 else
114                                         brelse(tmp);
115                         }
116                         if (num) {
117                                 ll_rw_block(REQ_OP_READ, REQ_RAHEAD, num, bha);
118                                 for (i = 0; i < num; i++)
119                                         brelse(bha[i]);
120                         }
121                 }
122         }
123
124         while (nf_pos < size) {
125                 struct kernel_lb_addr tloc;
126
127                 ctx->pos = (nf_pos >> 2) + 1;
128
129                 fi = udf_fileident_read(dir, &nf_pos, &fibh, &cfi, &epos, &eloc,
130                                         &elen, &offset);
131                 if (!fi)
132                         goto out;
133
134                 liu = le16_to_cpu(cfi.lengthOfImpUse);
135                 lfi = cfi.lengthFileIdent;
136
137                 if (fibh.sbh == fibh.ebh) {
138                         nameptr = fi->fileIdent + liu;
139                 } else {
140                         int poffset;    /* Unpaded ending offset */
141
142                         poffset = fibh.soffset + sizeof(struct fileIdentDesc) + liu + lfi;
143
144                         if (poffset >= lfi) {
145                                 nameptr = (char *)(fibh.ebh->b_data + poffset - lfi);
146                         } else {
147                                 if (!copy_name) {
148                                         copy_name = kmalloc(UDF_NAME_LEN,
149                                                             GFP_NOFS);
150                                         if (!copy_name) {
151                                                 ret = -ENOMEM;
152                                                 goto out;
153                                         }
154                                 }
155                                 nameptr = copy_name;
156                                 memcpy(nameptr, fi->fileIdent + liu,
157                                        lfi - poffset);
158                                 memcpy(nameptr + lfi - poffset,
159                                        fibh.ebh->b_data, poffset);
160                         }
161                 }
162
163                 if ((cfi.fileCharacteristics & FID_FILE_CHAR_DELETED) != 0) {
164                         if (!UDF_QUERY_FLAG(sb, UDF_FLAG_UNDELETE))
165                                 continue;
166                 }
167
168                 if ((cfi.fileCharacteristics & FID_FILE_CHAR_HIDDEN) != 0) {
169                         if (!UDF_QUERY_FLAG(sb, UDF_FLAG_UNHIDE))
170                                 continue;
171                 }
172
173                 if (cfi.fileCharacteristics & FID_FILE_CHAR_PARENT) {
174                         if (!dir_emit_dotdot(file, ctx))
175                                 goto out;
176                         continue;
177                 }
178
179                 flen = udf_get_filename(sb, nameptr, lfi, fname, UDF_NAME_LEN);
180                 if (flen < 0)
181                         continue;
182
183                 tloc = lelb_to_cpu(cfi.icb.extLocation);
184                 iblock = udf_get_lb_pblock(sb, &tloc, 0);
185                 if (!dir_emit(ctx, fname, flen, iblock, DT_UNKNOWN))
186                         goto out;
187         } /* end while */
188
189         ctx->pos = (nf_pos >> 2) + 1;
190
191 out:
192         if (fibh.sbh != fibh.ebh)
193                 brelse(fibh.ebh);
194         brelse(fibh.sbh);
195         brelse(epos.bh);
196         kfree(fname);
197         kfree(copy_name);
198
199         return ret;
200 }
201
202 /* readdir and lookup functions */
203 const struct file_operations udf_dir_operations = {
204         .llseek                 = generic_file_llseek,
205         .read                   = generic_read_dir,
206         .iterate_shared         = udf_readdir,
207         .unlocked_ioctl         = udf_ioctl,
208         .fsync                  = generic_file_fsync,
209 };