WSL2-Linux-Kernel/fs/udf/dir.c

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5.4 KiB
C
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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/smp_lock.h>
#include <linux/buffer_head.h>
#include "udf_i.h"
#include "udf_sb.h"
static int do_udf_readdir(struct inode *dir, struct file *filp,
filldir_t filldir, void *dirent)
{
struct udf_fileident_bh fibh = { .sbh = NULL, .ebh = NULL};
struct fileIdentDesc *fi = NULL;
struct fileIdentDesc cfi;
int block, iblock;
loff_t nf_pos = (filp->f_pos - 1) << 2;
int flen;
unsigned char *fname = 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;
unsigned int dt_type;
struct extent_position epos = { NULL, 0, {0, 0} };
struct udf_inode_info *iinfo;
if (nf_pos >= size)
goto out;
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 & (dir->i_sb->s_blocksize - 1);
iinfo = UDF_I(dir);
if (iinfo->i_alloc_type != ICBTAG_FLAG_AD_IN_ICB) {
if (inode_bmap(dir, nf_pos >> dir->i_sb->s_blocksize_bits,
&epos, &eloc, &elen, &offset)
!= (EXT_RECORDED_ALLOCATED >> 30)) {
ret = -ENOENT;
goto out;
}
block = udf_get_lb_pblock(dir->i_sb, &eloc, offset);
if ((++offset << dir->i_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(dir->i_sb, block))) {
ret = -EIO;
goto out;
}
if (!(offset & ((16 >> (dir->i_sb->s_blocksize_bits - 9)) - 1))) {
i = 16 >> (dir->i_sb->s_blocksize_bits - 9);
if (i + offset > (elen >> dir->i_sb->s_blocksize_bits))
i = (elen >> dir->i_sb->s_blocksize_bits) - offset;
for (num = 0; i > 0; i--) {
block = udf_get_lb_pblock(dir->i_sb, &eloc, offset + i);
tmp = udf_tgetblk(dir->i_sb, block);
if (tmp && !buffer_uptodate(tmp) && !buffer_locked(tmp))
bha[num++] = tmp;
else
brelse(tmp);
}
if (num) {
ll_rw_block(READA, num, bha);
for (i = 0; i < num; i++)
brelse(bha[i]);
}
}
}
while (nf_pos < size) {
filp->f_pos = (nf_pos >> 2) + 1;
fi = udf_fileident_read(dir, &nf_pos, &fibh, &cfi, &epos, &eloc,
&elen, &offset);
if (!fi)
goto out;
liu = le16_to_cpu(cfi.lengthOfImpUse);
lfi = cfi.lengthFileIdent;
if (fibh.sbh == fibh.ebh) {
nameptr = fi->fileIdent + liu;
} 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 {
nameptr = fname;
memcpy(nameptr, fi->fileIdent + liu,
lfi - poffset);
memcpy(nameptr + lfi - poffset,
fibh.ebh->b_data, poffset);
}
}
if ((cfi.fileCharacteristics & FID_FILE_CHAR_DELETED) != 0) {
if (!UDF_QUERY_FLAG(dir->i_sb, UDF_FLAG_UNDELETE))
continue;
}
if ((cfi.fileCharacteristics & FID_FILE_CHAR_HIDDEN) != 0) {
if (!UDF_QUERY_FLAG(dir->i_sb, UDF_FLAG_UNHIDE))
continue;
}
if (cfi.fileCharacteristics & FID_FILE_CHAR_PARENT) {
iblock = parent_ino(filp->f_path.dentry);
flen = 2;
memcpy(fname, "..", flen);
dt_type = DT_DIR;
} else {
struct kernel_lb_addr tloc = lelb_to_cpu(cfi.icb.extLocation);
iblock = udf_get_lb_pblock(dir->i_sb, &tloc, 0);
flen = udf_get_filename(dir->i_sb, nameptr, fname, lfi);
dt_type = DT_UNKNOWN;
}
if (flen && filldir(dirent, fname, flen, filp->f_pos,
iblock, dt_type) < 0)
goto out;
} /* end while */
filp->f_pos = (nf_pos >> 2) + 1;
out:
if (fibh.sbh != fibh.ebh)
brelse(fibh.ebh);
brelse(fibh.sbh);
brelse(epos.bh);
kfree(fname);
return ret;
}
static int udf_readdir(struct file *filp, void *dirent, filldir_t filldir)
{
struct inode *dir = filp->f_path.dentry->d_inode;
int result;
lock_kernel();
if (filp->f_pos == 0) {
if (filldir(dirent, ".", 1, filp->f_pos, dir->i_ino, DT_DIR) < 0) {
unlock_kernel();
return 0;
}
filp->f_pos++;
}
result = do_udf_readdir(dir, filp, filldir, dirent);
unlock_kernel();
return result;
}
/* readdir and lookup functions */
const struct file_operations udf_dir_operations = {
.llseek = generic_file_llseek,
.read = generic_read_dir,
.readdir = udf_readdir,
.unlocked_ioctl = udf_ioctl,
.fsync = generic_file_fsync,
};