Root/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/buffer_head.h>
34
35#include "udf_i.h"
36#include "udf_sb.h"
37
38static int do_udf_readdir(struct inode *dir, struct file *filp,
39              filldir_t filldir, void *dirent)
40{
41    struct udf_fileident_bh fibh = { .sbh = NULL, .ebh = NULL};
42    struct fileIdentDesc *fi = NULL;
43    struct fileIdentDesc cfi;
44    int block, iblock;
45    loff_t nf_pos = (filp->f_pos - 1) << 2;
46    int flen;
47    unsigned char *fname = NULL;
48    unsigned char *nameptr;
49    uint16_t liu;
50    uint8_t lfi;
51    loff_t size = udf_ext0_offset(dir) + dir->i_size;
52    struct buffer_head *tmp, *bha[16];
53    struct kernel_lb_addr eloc;
54    uint32_t elen;
55    sector_t offset;
56    int i, num, ret = 0;
57    unsigned int dt_type;
58    struct extent_position epos = { NULL, 0, {0, 0} };
59    struct udf_inode_info *iinfo;
60
61    if (nf_pos >= size)
62        goto out;
63
64    fname = kmalloc(UDF_NAME_LEN, GFP_NOFS);
65    if (!fname) {
66        ret = -ENOMEM;
67        goto out;
68    }
69
70    if (nf_pos == 0)
71        nf_pos = udf_ext0_offset(dir);
72
73    fibh.soffset = fibh.eoffset = nf_pos & (dir->i_sb->s_blocksize - 1);
74    iinfo = UDF_I(dir);
75    if (iinfo->i_alloc_type != ICBTAG_FLAG_AD_IN_ICB) {
76        if (inode_bmap(dir, nf_pos >> dir->i_sb->s_blocksize_bits,
77            &epos, &eloc, &elen, &offset)
78            != (EXT_RECORDED_ALLOCATED >> 30)) {
79            ret = -ENOENT;
80            goto out;
81        }
82        block = udf_get_lb_pblock(dir->i_sb, &eloc, offset);
83        if ((++offset << dir->i_sb->s_blocksize_bits) < elen) {
84            if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT)
85                epos.offset -= sizeof(struct short_ad);
86            else if (iinfo->i_alloc_type ==
87                    ICBTAG_FLAG_AD_LONG)
88                epos.offset -= sizeof(struct long_ad);
89        } else {
90            offset = 0;
91        }
92
93        if (!(fibh.sbh = fibh.ebh = udf_tread(dir->i_sb, block))) {
94            ret = -EIO;
95            goto out;
96        }
97
98        if (!(offset & ((16 >> (dir->i_sb->s_blocksize_bits - 9)) - 1))) {
99            i = 16 >> (dir->i_sb->s_blocksize_bits - 9);
100            if (i + offset > (elen >> dir->i_sb->s_blocksize_bits))
101                i = (elen >> dir->i_sb->s_blocksize_bits) - offset;
102            for (num = 0; i > 0; i--) {
103                block = udf_get_lb_pblock(dir->i_sb, &eloc, offset + i);
104                tmp = udf_tgetblk(dir->i_sb, block);
105                if (tmp && !buffer_uptodate(tmp) && !buffer_locked(tmp))
106                    bha[num++] = tmp;
107                else
108                    brelse(tmp);
109            }
110            if (num) {
111                ll_rw_block(READA, num, bha);
112                for (i = 0; i < num; i++)
113                    brelse(bha[i]);
114            }
115        }
116    }
117
118    while (nf_pos < size) {
119        filp->f_pos = (nf_pos >> 2) + 1;
120
121        fi = udf_fileident_read(dir, &nf_pos, &fibh, &cfi, &epos, &eloc,
122                    &elen, &offset);
123        if (!fi)
124            goto out;
125
126        liu = le16_to_cpu(cfi.lengthOfImpUse);
127        lfi = cfi.lengthFileIdent;
128
129        if (fibh.sbh == fibh.ebh) {
130            nameptr = fi->fileIdent + liu;
131        } else {
132            int poffset; /* Unpaded ending offset */
133
134            poffset = fibh.soffset + sizeof(struct fileIdentDesc) + liu + lfi;
135
136            if (poffset >= lfi) {
137                nameptr = (char *)(fibh.ebh->b_data + poffset - lfi);
138            } else {
139                nameptr = fname;
140                memcpy(nameptr, fi->fileIdent + liu,
141                       lfi - poffset);
142                memcpy(nameptr + lfi - poffset,
143                       fibh.ebh->b_data, poffset);
144            }
145        }
146
147        if ((cfi.fileCharacteristics & FID_FILE_CHAR_DELETED) != 0) {
148            if (!UDF_QUERY_FLAG(dir->i_sb, UDF_FLAG_UNDELETE))
149                continue;
150        }
151
152        if ((cfi.fileCharacteristics & FID_FILE_CHAR_HIDDEN) != 0) {
153            if (!UDF_QUERY_FLAG(dir->i_sb, UDF_FLAG_UNHIDE))
154                continue;
155        }
156
157        if (cfi.fileCharacteristics & FID_FILE_CHAR_PARENT) {
158            iblock = parent_ino(filp->f_path.dentry);
159            flen = 2;
160            memcpy(fname, "..", flen);
161            dt_type = DT_DIR;
162        } else {
163            struct kernel_lb_addr tloc = lelb_to_cpu(cfi.icb.extLocation);
164
165            iblock = udf_get_lb_pblock(dir->i_sb, &tloc, 0);
166            flen = udf_get_filename(dir->i_sb, nameptr, fname, lfi);
167            dt_type = DT_UNKNOWN;
168        }
169
170        if (flen && filldir(dirent, fname, flen, filp->f_pos,
171                    iblock, dt_type) < 0)
172            goto out;
173    } /* end while */
174
175    filp->f_pos = (nf_pos >> 2) + 1;
176
177out:
178    if (fibh.sbh != fibh.ebh)
179        brelse(fibh.ebh);
180    brelse(fibh.sbh);
181    brelse(epos.bh);
182    kfree(fname);
183
184    return ret;
185}
186
187static int udf_readdir(struct file *filp, void *dirent, filldir_t filldir)
188{
189    struct inode *dir = filp->f_path.dentry->d_inode;
190    int result;
191
192    if (filp->f_pos == 0) {
193        if (filldir(dirent, ".", 1, filp->f_pos, dir->i_ino, DT_DIR) < 0) {
194            return 0;
195        }
196        filp->f_pos++;
197    }
198
199    result = do_udf_readdir(dir, filp, filldir, dirent);
200     return result;
201}
202
203/* readdir and lookup functions */
204const struct file_operations udf_dir_operations = {
205    .llseek = generic_file_llseek,
206    .read = generic_read_dir,
207    .readdir = udf_readdir,
208    .unlocked_ioctl = udf_ioctl,
209    .fsync = generic_file_fsync,
210};
211

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