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