fs/udf/directory.c

0001 /*
0002  * directory.c
0003  *
0004  * PURPOSE
0005  *  Directory related functions
0006  *
0007  * COPYRIGHT
0008  *  This file is distributed under the terms of the GNU General Public
0009  *  License (GPL). Copies of the GPL can be obtained from:
0010  *      ftp://prep.ai.mit.edu/pub/gnu/GPL
0011  *  Each contributing author retains all rights to their own work.
0012  */
0013
0014 #include "udfdecl.h"
0015 #include "udf_i.h"
0016
0017 #include <linux/fs.h>
0018 #include <linux/string.h>
0019 #include <linux/bio.h>
0020
0021 struct fileIdentDesc *udf_fileident_read(struct inode *dir, loff_t *nf_pos,
0022                      struct udf_fileident_bh *fibh,
0023                      struct fileIdentDesc *cfi,
0024                      struct extent_position *epos,
0025                      struct kernel_lb_addr *eloc, uint32_t *elen,
0026                      sector_t *offset)
0027 {
0028     struct fileIdentDesc *fi;
0029     int i, num;
0030     udf_pblk_t block;
0031     struct buffer_head *tmp, *bha[16];
0032     struct udf_inode_info *iinfo = UDF_I(dir);
0033
0034     fibh->soffset = fibh->eoffset;
0035
0036     if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB) {
0037         fi = udf_get_fileident(iinfo->i_data -
0038                        (iinfo->i_efe ?
0039                     sizeof(struct extendedFileEntry) :
0040                     sizeof(struct fileEntry)),
0041                        dir->i_sb->s_blocksize,
0042                        &(fibh->eoffset));
0043         if (!fi)
0044             return NULL;
0045
0046         *nf_pos += fibh->eoffset - fibh->soffset;
0047
0048         memcpy((uint8_t *)cfi, (uint8_t *)fi,
0049                sizeof(struct fileIdentDesc));
0050
0051         return fi;
0052     }
0053
0054     if (fibh->eoffset == dir->i_sb->s_blocksize) {
0055         uint32_t lextoffset = epos->offset;
0056         unsigned char blocksize_bits = dir->i_sb->s_blocksize_bits;
0057
0058         if (udf_next_aext(dir, epos, eloc, elen, 1) !=
0059             (EXT_RECORDED_ALLOCATED >> 30))
0060             return NULL;
0061
0062         block = udf_get_lb_pblock(dir->i_sb, eloc, *offset);
0063
0064         (*offset)++;
0065
0066         if ((*offset << blocksize_bits) >= *elen)
0067             *offset = 0;
0068         else
0069             epos->offset = lextoffset;
0070
0071         brelse(fibh->sbh);
0072         fibh->sbh = fibh->ebh = udf_tread(dir->i_sb, block);
0073         if (!fibh->sbh)
0074             return NULL;
0075         fibh->soffset = fibh->eoffset = 0;
0076
0077         if (!(*offset & ((16 >> (blocksize_bits - 9)) - 1))) {
0078             i = 16 >> (blocksize_bits - 9);
0079             if (i + *offset > (*elen >> blocksize_bits))
0080                 i = (*elen >> blocksize_bits)-*offset;
0081             for (num = 0; i > 0; i--) {
0082                 block = udf_get_lb_pblock(dir->i_sb, eloc,
0083                               *offset + i);
0084                 tmp = udf_tgetblk(dir->i_sb, block);
0085                 if (tmp && !buffer_uptodate(tmp) &&
0086                         !buffer_locked(tmp))
0087                     bha[num++] = tmp;
0088                 else
0089                     brelse(tmp);
0090             }
0091             if (num) {
0092                 ll_rw_block(REQ_OP_READ | REQ_RAHEAD, num, bha);
0093                 for (i = 0; i < num; i++)
0094                     brelse(bha[i]);
0095             }
0096         }
0097     } else if (fibh->sbh != fibh->ebh) {
0098         brelse(fibh->sbh);
0099         fibh->sbh = fibh->ebh;
0100     }
0101
0102     fi = udf_get_fileident(fibh->sbh->b_data, dir->i_sb->s_blocksize,
0103                    &(fibh->eoffset));
0104
0105     if (!fi)
0106         return NULL;
0107
0108     *nf_pos += fibh->eoffset - fibh->soffset;
0109
0110     if (fibh->eoffset <= dir->i_sb->s_blocksize) {
0111         memcpy((uint8_t *)cfi, (uint8_t *)fi,
0112                sizeof(struct fileIdentDesc));
0113     } else if (fibh->eoffset > dir->i_sb->s_blocksize) {
0114         uint32_t lextoffset = epos->offset;
0115
0116         if (udf_next_aext(dir, epos, eloc, elen, 1) !=
0117             (EXT_RECORDED_ALLOCATED >> 30))
0118             return NULL;
0119
0120         block = udf_get_lb_pblock(dir->i_sb, eloc, *offset);
0121
0122         (*offset)++;
0123
0124         if ((*offset << dir->i_sb->s_blocksize_bits) >= *elen)
0125             *offset = 0;
0126         else
0127             epos->offset = lextoffset;
0128
0129         fibh->soffset -= dir->i_sb->s_blocksize;
0130         fibh->eoffset -= dir->i_sb->s_blocksize;
0131
0132         fibh->ebh = udf_tread(dir->i_sb, block);
0133         if (!fibh->ebh)
0134             return NULL;
0135
0136         if (sizeof(struct fileIdentDesc) > -fibh->soffset) {
0137             int fi_len;
0138
0139             memcpy((uint8_t *)cfi, (uint8_t *)fi, -fibh->soffset);
0140             memcpy((uint8_t *)cfi - fibh->soffset,
0141                    fibh->ebh->b_data,
0142                    sizeof(struct fileIdentDesc) + fibh->soffset);
0143
0144             fi_len = udf_dir_entry_len(cfi);
0145             *nf_pos += fi_len - (fibh->eoffset - fibh->soffset);
0146             fibh->eoffset = fibh->soffset + fi_len;
0147         } else {
0148             memcpy((uint8_t *)cfi, (uint8_t *)fi,
0149                    sizeof(struct fileIdentDesc));
0150         }
0151     }
0152     /* Got last entry outside of dir size - fs is corrupted! */
0153     if (*nf_pos > dir->i_size)
0154         return NULL;
0155     return fi;
0156 }
0157
0158 struct fileIdentDesc *udf_get_fileident(void *buffer, int bufsize, int *offset)
0159 {
0160     struct fileIdentDesc *fi;
0161     int lengthThisIdent;
0162     uint8_t *ptr;
0163     int padlen;
0164
0165     if ((!buffer) || (!offset)) {
0166         udf_debug("invalidparms, buffer=%p, offset=%p\n",
0167               buffer, offset);
0168         return NULL;
0169     }
0170
0171     ptr = buffer;
0172
0173     if ((*offset > 0) && (*offset < bufsize))
0174         ptr += *offset;
0175     fi = (struct fileIdentDesc *)ptr;
0176     if (fi->descTag.tagIdent != cpu_to_le16(TAG_IDENT_FID)) {
0177         udf_debug("0x%x != TAG_IDENT_FID\n",
0178               le16_to_cpu(fi->descTag.tagIdent));
0179         udf_debug("offset: %d sizeof: %lu bufsize: %d\n",
0180               *offset, (unsigned long)sizeof(struct fileIdentDesc),
0181               bufsize);
0182         return NULL;
0183     }
0184     if ((*offset + sizeof(struct fileIdentDesc)) > bufsize)
0185         lengthThisIdent = sizeof(struct fileIdentDesc);
0186     else
0187         lengthThisIdent = sizeof(struct fileIdentDesc) +
0188             fi->lengthFileIdent + le16_to_cpu(fi->lengthOfImpUse);
0189
0190     /* we need to figure padding, too! */
0191     padlen = lengthThisIdent % UDF_NAME_PAD;
0192     if (padlen)
0193         lengthThisIdent += (UDF_NAME_PAD - padlen);
0194     *offset = *offset + lengthThisIdent;
0195
0196     return fi;
0197 }
0198
0199 struct short_ad *udf_get_fileshortad(uint8_t *ptr, int maxoffset, uint32_t *offset,
0200                   int inc)
0201 {
0202     struct short_ad *sa;
0203
0204     if ((!ptr) || (!offset)) {
0205         pr_err("%s: invalidparms\n", __func__);
0206         return NULL;
0207     }
0208
0209     if ((*offset + sizeof(struct short_ad)) > maxoffset)
0210         return NULL;
0211     else {
0212         sa = (struct short_ad *)ptr;
0213         if (sa->extLength == 0)
0214             return NULL;
0215     }
0216
0217     if (inc)
0218         *offset += sizeof(struct short_ad);
0219     return sa;
0220 }
0221
0222 struct long_ad *udf_get_filelongad(uint8_t *ptr, int maxoffset, uint32_t *offset, int inc)
0223 {
0224     struct long_ad *la;
0225
0226     if ((!ptr) || (!offset)) {
0227         pr_err("%s: invalidparms\n", __func__);
0228         return NULL;
0229     }
0230
0231     if ((*offset + sizeof(struct long_ad)) > maxoffset)
0232         return NULL;
0233     else {
0234         la = (struct long_ad *)ptr;
0235         if (la->extLength == 0)
0236             return NULL;
0237     }
0238
0239     if (inc)
0240         *offset += sizeof(struct long_ad);
0241     return la;
0242 }