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#include <linux/iversion.h> 35 36#include "udf_i.h" 37#include "udf_sb.h" 38 39 40static int udf_readdir(struct file *file, struct dir_context *ctx) 41{ 42 struct inode *dir = file_inode(file); 43 struct udf_inode_info *iinfo = UDF_I(dir); 44 struct udf_fileident_bh fibh = { .sbh = NULL, .ebh = NULL}; 45 struct fileIdentDesc *fi = NULL; 46 struct fileIdentDesc cfi; 47 udf_pblk_t block, iblock; 48 loff_t nf_pos, emit_pos = 0; 49 int flen; 50 unsigned char *fname = NULL, *copy_name = NULL; 51 unsigned char *nameptr; 52 uint16_t liu; 53 uint8_t lfi; 54 loff_t size = udf_ext0_offset(dir) + dir->i_size; 55 struct buffer_head *tmp, *bha[16]; 56 struct kernel_lb_addr eloc; 57 uint32_t elen; 58 sector_t offset; 59 int i, num, ret = 0; 60 struct extent_position epos = { NULL, 0, {0, 0} }; 61 struct super_block *sb = dir->i_sb; 62 bool pos_valid = false; 63 64 if (ctx->pos == 0) { 65 if (!dir_emit_dot(file, ctx)) 66 return 0; 67 ctx->pos = 1; 68 } 69 nf_pos = (ctx->pos - 1) << 2; 70 if (nf_pos >= size) 71 goto out; 72 73 /* 74 * Something changed since last readdir (either lseek was called or dir 75 * changed)? We need to verify the position correctly points at the 76 * beginning of some dir entry so that the directory parsing code does 77 * not get confused. Since UDF does not have any reliable way of 78 * identifying beginning of dir entry (names are under user control), 79 * we need to scan the directory from the beginning. 80 */ 81 if (!inode_eq_iversion(dir, file->f_version)) { 82 emit_pos = nf_pos; 83 nf_pos = 0; 84 } else { 85 pos_valid = true; 86 } 87 88 fname = kmalloc(UDF_NAME_LEN, GFP_NOFS); 89 if (!fname) { 90 ret = -ENOMEM; 91 goto out; 92 } 93 94 if (nf_pos == 0) 95 nf_pos = udf_ext0_offset(dir); 96 97 fibh.soffset = fibh.eoffset = nf_pos & (sb->s_blocksize - 1); 98 if (iinfo->i_alloc_type != ICBTAG_FLAG_AD_IN_ICB) { 99 if (inode_bmap(dir, nf_pos >> sb->s_blocksize_bits, 100 &epos, &eloc, &elen, &offset) 101 != (EXT_RECORDED_ALLOCATED >> 30)) { 102 ret = -ENOENT; 103 goto out; 104 } 105 block = udf_get_lb_pblock(sb, &eloc, offset); 106 if ((++offset << sb->s_blocksize_bits) < elen) { 107 if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT) 108 epos.offset -= sizeof(struct short_ad); 109 else if (iinfo->i_alloc_type == 110 ICBTAG_FLAG_AD_LONG) 111 epos.offset -= sizeof(struct long_ad); 112 } else { 113 offset = 0; 114 } 115 116 if (!(fibh.sbh = fibh.ebh = udf_tread(sb, block))) { 117 ret = -EIO; 118 goto out; 119 } 120 121 if (!(offset & ((16 >> (sb->s_blocksize_bits - 9)) - 1))) { 122 i = 16 >> (sb->s_blocksize_bits - 9); 123 if (i + offset > (elen >> sb->s_blocksize_bits)) 124 i = (elen >> sb->s_blocksize_bits) - offset; 125 for (num = 0; i > 0; i--) { 126 block = udf_get_lb_pblock(sb, &eloc, offset + i); 127 tmp = udf_tgetblk(sb, block); 128 if (tmp && !buffer_uptodate(tmp) && !buffer_locked(tmp)) 129 bha[num++] = tmp; 130 else 131 brelse(tmp); 132 } 133 if (num) { 134 ll_rw_block(REQ_OP_READ, REQ_RAHEAD, num, bha); 135 for (i = 0; i < num; i++) 136 brelse(bha[i]); 137 } 138 } 139 } 140 141 while (nf_pos < size) { 142 struct kernel_lb_addr tloc; 143 loff_t cur_pos = nf_pos; 144 145 /* Update file position only if we got past the current one */ 146 if (nf_pos >= emit_pos) { 147 ctx->pos = (nf_pos >> 2) + 1; 148 pos_valid = true; 149 } 150 151 fi = udf_fileident_read(dir, &nf_pos, &fibh, &cfi, &epos, &eloc, 152 &elen, &offset); 153 if (!fi) 154 goto out; 155 /* Still not at offset where user asked us to read from? */ 156 if (cur_pos < emit_pos) 157 continue; 158 159 liu = le16_to_cpu(cfi.lengthOfImpUse); 160 lfi = cfi.lengthFileIdent; 161 162 if (fibh.sbh == fibh.ebh) { 163 nameptr = fi->fileIdent + liu; 164 } else { 165 int poffset; /* Unpaded ending offset */ 166 167 poffset = fibh.soffset + sizeof(struct fileIdentDesc) + liu + lfi; 168 169 if (poffset >= lfi) { 170 nameptr = (char *)(fibh.ebh->b_data + poffset - lfi); 171 } else { 172 if (!copy_name) { 173 copy_name = kmalloc(UDF_NAME_LEN, 174 GFP_NOFS); 175 if (!copy_name) { 176 ret = -ENOMEM; 177 goto out; 178 } 179 } 180 nameptr = copy_name; 181 memcpy(nameptr, fi->fileIdent + liu, 182 lfi - poffset); 183 memcpy(nameptr + lfi - poffset, 184 fibh.ebh->b_data, poffset); 185 } 186 } 187 188 if ((cfi.fileCharacteristics & FID_FILE_CHAR_DELETED) != 0) { 189 if (!UDF_QUERY_FLAG(sb, UDF_FLAG_UNDELETE)) 190 continue; 191 } 192 193 if ((cfi.fileCharacteristics & FID_FILE_CHAR_HIDDEN) != 0) { 194 if (!UDF_QUERY_FLAG(sb, UDF_FLAG_UNHIDE)) 195 continue; 196 } 197 198 if (cfi.fileCharacteristics & FID_FILE_CHAR_PARENT) { 199 if (!dir_emit_dotdot(file, ctx)) 200 goto out; 201 continue; 202 } 203 204 flen = udf_get_filename(sb, nameptr, lfi, fname, UDF_NAME_LEN); 205 if (flen < 0) 206 continue; 207 208 tloc = lelb_to_cpu(cfi.icb.extLocation); 209 iblock = udf_get_lb_pblock(sb, &tloc, 0); 210 if (!dir_emit(ctx, fname, flen, iblock, DT_UNKNOWN)) 211 goto out; 212 } /* end while */ 213 214 ctx->pos = (nf_pos >> 2) + 1; 215 pos_valid = true; 216 217out: 218 if (pos_valid) 219 file->f_version = inode_query_iversion(dir); 220 if (fibh.sbh != fibh.ebh) 221 brelse(fibh.ebh); 222 brelse(fibh.sbh); 223 brelse(epos.bh); 224 kfree(fname); 225 kfree(copy_name); 226 227 return ret; 228} 229 230/* readdir and lookup functions */ 231const struct file_operations udf_dir_operations = { 232 .llseek = generic_file_llseek, 233 .read = generic_read_dir, 234 .iterate_shared = udf_readdir, 235 .unlocked_ioctl = udf_ioctl, 236 .fsync = generic_file_fsync, 237}; 238