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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);
loff_t nf_pos, emit_pos = 0;
int flen;
unsigned char *fname = NULL;
int ret = 0;
struct super_block *sb = dir->i_sb;
bool pos_valid = false;
struct udf_fileident_iter iter;
if (ctx->pos == 0) {
if (!dir_emit_dot(file, ctx))
return 0;
ctx->pos = 1;
}
nf_pos = (ctx->pos - 1) << 2;
if (nf_pos >= dir->i_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;
}
for (ret = udf_fiiter_init(&iter, dir, nf_pos);
!ret && iter.pos < dir->i_size;
ret = udf_fiiter_advance(&iter)) {
struct kernel_lb_addr tloc;
udf_pblk_t iblock;
/* Still not at offset where user asked us to read from? */
if (iter.pos < emit_pos)
continue;
/* Update file position only if we got past the current one */
pos_valid = true;
ctx->pos = (iter.pos >> 2) + 1;
if (iter.fi.fileCharacteristics & FID_FILE_CHAR_DELETED) {
if (!UDF_QUERY_FLAG(sb, UDF_FLAG_UNDELETE))
continue;
}
if (iter.fi.fileCharacteristics & FID_FILE_CHAR_HIDDEN) {
if (!UDF_QUERY_FLAG(sb, UDF_FLAG_UNHIDE))
continue;
}
if (iter.fi.fileCharacteristics & FID_FILE_CHAR_PARENT) {
if (!dir_emit_dotdot(file, ctx))
goto out_iter;
continue;
}
flen = udf_get_filename(sb, iter.name,
iter.fi.lengthFileIdent, fname, UDF_NAME_LEN);
if (flen < 0)
continue;
tloc = lelb_to_cpu(iter.fi.icb.extLocation);
iblock = udf_get_lb_pblock(sb, &tloc, 0);
if (!dir_emit(ctx, fname, flen, iblock, DT_UNKNOWN))
goto out_iter;
}
if (!ret) {
ctx->pos = (iter.pos >> 2) + 1;
pos_valid = true;
}
out_iter:
udf_fiiter_release(&iter);
out:
if (pos_valid)
file->f_version = inode_query_iversion(dir);
kfree(fname);
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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