xref: /openbmc/linux/fs/udf/dir.c (revision 2209fda3)
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  	udf_pblk_t 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  };
210