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