238 lines
6.1 KiB
C
238 lines
6.1 KiB
C
/*
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* dir.c
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*
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* PURPOSE
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* Directory handling routines for the OSTA-UDF(tm) filesystem.
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*
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* COPYRIGHT
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* This file is distributed under the terms of the GNU General Public
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* License (GPL). Copies of the GPL can be obtained from:
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* ftp://prep.ai.mit.edu/pub/gnu/GPL
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* Each contributing author retains all rights to their own work.
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*
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* (C) 1998-2004 Ben Fennema
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*
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* HISTORY
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*
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* 10/05/98 dgb Split directory operations into its own file
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* Implemented directory reads via do_udf_readdir
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* 10/06/98 Made directory operations work!
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* 11/17/98 Rewrote directory to support ICBTAG_FLAG_AD_LONG
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* 11/25/98 blf Rewrote directory handling (readdir+lookup) to support reading
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* across blocks.
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* 12/12/98 Split out the lookup code to namei.c. bulk of directory
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* code now in directory.c:udf_fileident_read.
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*/
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#include "udfdecl.h"
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#include <linux/string.h>
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#include <linux/errno.h>
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#include <linux/mm.h>
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#include <linux/slab.h>
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#include <linux/bio.h>
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#include <linux/iversion.h>
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#include "udf_i.h"
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#include "udf_sb.h"
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static int udf_readdir(struct file *file, struct dir_context *ctx)
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{
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struct inode *dir = file_inode(file);
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struct udf_inode_info *iinfo = UDF_I(dir);
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struct udf_fileident_bh fibh = { .sbh = NULL, .ebh = NULL};
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struct fileIdentDesc *fi = NULL;
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struct fileIdentDesc cfi;
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udf_pblk_t block, iblock;
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loff_t nf_pos, emit_pos = 0;
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int flen;
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unsigned char *fname = NULL, *copy_name = NULL;
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unsigned char *nameptr;
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uint16_t liu;
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uint8_t lfi;
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loff_t size = udf_ext0_offset(dir) + dir->i_size;
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struct buffer_head *tmp, *bha[16];
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struct kernel_lb_addr eloc;
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uint32_t elen;
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sector_t offset;
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int i, num, ret = 0;
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struct extent_position epos = { NULL, 0, {0, 0} };
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struct super_block *sb = dir->i_sb;
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bool pos_valid = false;
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if (ctx->pos == 0) {
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if (!dir_emit_dot(file, ctx))
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return 0;
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ctx->pos = 1;
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}
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nf_pos = (ctx->pos - 1) << 2;
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if (nf_pos >= size)
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goto out;
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/*
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* Something changed since last readdir (either lseek was called or dir
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* changed)? We need to verify the position correctly points at the
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* beginning of some dir entry so that the directory parsing code does
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* not get confused. Since UDF does not have any reliable way of
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* identifying beginning of dir entry (names are under user control),
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* we need to scan the directory from the beginning.
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*/
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if (!inode_eq_iversion(dir, file->f_version)) {
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emit_pos = nf_pos;
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nf_pos = 0;
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} else {
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pos_valid = true;
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}
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fname = kmalloc(UDF_NAME_LEN, GFP_NOFS);
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if (!fname) {
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ret = -ENOMEM;
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goto out;
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}
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if (nf_pos == 0)
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nf_pos = udf_ext0_offset(dir);
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fibh.soffset = fibh.eoffset = nf_pos & (sb->s_blocksize - 1);
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if (iinfo->i_alloc_type != ICBTAG_FLAG_AD_IN_ICB) {
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if (inode_bmap(dir, nf_pos >> sb->s_blocksize_bits,
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&epos, &eloc, &elen, &offset)
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!= (EXT_RECORDED_ALLOCATED >> 30)) {
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ret = -ENOENT;
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goto out;
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}
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block = udf_get_lb_pblock(sb, &eloc, offset);
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if ((++offset << sb->s_blocksize_bits) < elen) {
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if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT)
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epos.offset -= sizeof(struct short_ad);
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else if (iinfo->i_alloc_type ==
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ICBTAG_FLAG_AD_LONG)
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epos.offset -= sizeof(struct long_ad);
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} else {
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offset = 0;
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}
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if (!(fibh.sbh = fibh.ebh = udf_tread(sb, block))) {
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ret = -EIO;
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goto out;
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}
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if (!(offset & ((16 >> (sb->s_blocksize_bits - 9)) - 1))) {
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i = 16 >> (sb->s_blocksize_bits - 9);
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if (i + offset > (elen >> sb->s_blocksize_bits))
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i = (elen >> sb->s_blocksize_bits) - offset;
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for (num = 0; i > 0; i--) {
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block = udf_get_lb_pblock(sb, &eloc, offset + i);
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tmp = udf_tgetblk(sb, block);
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if (tmp && !buffer_uptodate(tmp) && !buffer_locked(tmp))
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bha[num++] = tmp;
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else
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brelse(tmp);
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}
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if (num) {
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ll_rw_block(REQ_OP_READ, REQ_RAHEAD, num, bha);
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for (i = 0; i < num; i++)
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brelse(bha[i]);
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}
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}
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}
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while (nf_pos < size) {
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struct kernel_lb_addr tloc;
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loff_t cur_pos = nf_pos;
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/* Update file position only if we got past the current one */
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if (nf_pos >= emit_pos) {
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ctx->pos = (nf_pos >> 2) + 1;
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pos_valid = true;
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}
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fi = udf_fileident_read(dir, &nf_pos, &fibh, &cfi, &epos, &eloc,
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&elen, &offset);
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if (!fi)
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goto out;
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/* Still not at offset where user asked us to read from? */
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if (cur_pos < emit_pos)
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continue;
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liu = le16_to_cpu(cfi.lengthOfImpUse);
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lfi = cfi.lengthFileIdent;
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if (fibh.sbh == fibh.ebh) {
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nameptr = fi->fileIdent + liu;
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} else {
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int poffset; /* Unpaded ending offset */
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poffset = fibh.soffset + sizeof(struct fileIdentDesc) + liu + lfi;
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if (poffset >= lfi) {
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nameptr = (char *)(fibh.ebh->b_data + poffset - lfi);
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} else {
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if (!copy_name) {
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copy_name = kmalloc(UDF_NAME_LEN,
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GFP_NOFS);
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if (!copy_name) {
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ret = -ENOMEM;
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goto out;
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}
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}
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nameptr = copy_name;
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memcpy(nameptr, fi->fileIdent + liu,
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lfi - poffset);
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memcpy(nameptr + lfi - poffset,
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fibh.ebh->b_data, poffset);
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}
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}
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if ((cfi.fileCharacteristics & FID_FILE_CHAR_DELETED) != 0) {
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if (!UDF_QUERY_FLAG(sb, UDF_FLAG_UNDELETE))
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continue;
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}
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if ((cfi.fileCharacteristics & FID_FILE_CHAR_HIDDEN) != 0) {
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if (!UDF_QUERY_FLAG(sb, UDF_FLAG_UNHIDE))
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continue;
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}
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if (cfi.fileCharacteristics & FID_FILE_CHAR_PARENT) {
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if (!dir_emit_dotdot(file, ctx))
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goto out;
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continue;
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}
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flen = udf_get_filename(sb, nameptr, lfi, fname, UDF_NAME_LEN);
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if (flen < 0)
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continue;
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tloc = lelb_to_cpu(cfi.icb.extLocation);
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iblock = udf_get_lb_pblock(sb, &tloc, 0);
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if (!dir_emit(ctx, fname, flen, iblock, DT_UNKNOWN))
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goto out;
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} /* end while */
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ctx->pos = (nf_pos >> 2) + 1;
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pos_valid = true;
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out:
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if (pos_valid)
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file->f_version = inode_query_iversion(dir);
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if (fibh.sbh != fibh.ebh)
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brelse(fibh.ebh);
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brelse(fibh.sbh);
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brelse(epos.bh);
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kfree(fname);
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kfree(copy_name);
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return ret;
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}
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/* readdir and lookup functions */
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const struct file_operations udf_dir_operations = {
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.llseek = generic_file_llseek,
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.read = generic_read_dir,
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.iterate_shared = udf_readdir,
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.unlocked_ioctl = udf_ioctl,
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.fsync = generic_file_fsync,
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};
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