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linux/fs/udf/truncate.c
Jan Kara 101ee137d3 udf: Drop VARCONV support 
UDF was supporting a strange mode where the media was containing 7
blocks of unknown data for every 32 blocks of the filesystem. I have yet
to see the media that would need such conversion (maybe it comes from
packet writing times) and the conversions have been inconsistent in the
code. In particular any write will write to a wrong block and corrupt
the media. This is an indication and no user actually needs this so
let's just drop the support instead of trying to fix it.

Signed-off-by: Jan Kara <jack@suse.cz>
2023-01-26 16:46:32 +01:00

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/*
* truncate.c
*
* PURPOSE
* Truncate 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) 1999-2004 Ben Fennema
* (C) 1999 Stelias Computing Inc
*
* HISTORY
*
* 02/24/99 blf Created.
*
*/
#include "udfdecl.h"
#include <linux/fs.h>
#include <linux/mm.h>
#include "udf_i.h"
#include "udf_sb.h"
static void extent_trunc(struct inode *inode, struct extent_position *epos,
struct kernel_lb_addr *eloc, int8_t etype, uint32_t elen,
uint32_t nelen)
{
struct kernel_lb_addr neloc = {};
int last_block = (elen + inode->i_sb->s_blocksize - 1) >>
inode->i_sb->s_blocksize_bits;
int first_block = (nelen + inode->i_sb->s_blocksize - 1) >>
inode->i_sb->s_blocksize_bits;
if (nelen) {
if (etype == (EXT_NOT_RECORDED_ALLOCATED >> 30)) {
udf_free_blocks(inode->i_sb, inode, eloc, 0,
last_block);
etype = (EXT_NOT_RECORDED_NOT_ALLOCATED >> 30);
} else
neloc = *eloc;
nelen = (etype << 30) | nelen;
}
if (elen != nelen) {
udf_write_aext(inode, epos, &neloc, nelen, 0);
if (last_block > first_block) {
if (etype == (EXT_RECORDED_ALLOCATED >> 30))
mark_inode_dirty(inode);
if (etype != (EXT_NOT_RECORDED_NOT_ALLOCATED >> 30))
udf_free_blocks(inode->i_sb, inode, eloc,
first_block,
last_block - first_block);
}
}
}
/*
* Truncate the last extent to match i_size. This function assumes
* that preallocation extent is already truncated.
*/
void udf_truncate_tail_extent(struct inode *inode)
{
struct extent_position epos = {};
struct kernel_lb_addr eloc;
uint32_t elen, nelen;
uint64_t lbcount = 0;
int8_t etype = -1, netype;
int adsize;
struct udf_inode_info *iinfo = UDF_I(inode);
if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB ||
inode->i_size == iinfo->i_lenExtents)
return;
/* Are we going to delete the file anyway? */
if (inode->i_nlink == 0)
return;
if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT)
adsize = sizeof(struct short_ad);
else if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_LONG)
adsize = sizeof(struct long_ad);
else
BUG();
/* Find the last extent in the file */
while ((netype = udf_next_aext(inode, &epos, &eloc, &elen, 1)) != -1) {
etype = netype;
lbcount += elen;
if (lbcount > inode->i_size) {
if (lbcount - inode->i_size >= inode->i_sb->s_blocksize)
udf_warn(inode->i_sb,
"Too long extent after EOF in inode %u: i_size: %lld lbcount: %lld extent %u+%u\n",
(unsigned)inode->i_ino,
(long long)inode->i_size,
(long long)lbcount,
(unsigned)eloc.logicalBlockNum,
(unsigned)elen);
nelen = elen - (lbcount - inode->i_size);
epos.offset -= adsize;
extent_trunc(inode, &epos, &eloc, etype, elen, nelen);
epos.offset += adsize;
if (udf_next_aext(inode, &epos, &eloc, &elen, 1) != -1)
udf_err(inode->i_sb,
"Extent after EOF in inode %u\n",
(unsigned)inode->i_ino);
break;
}
}
/* This inode entry is in-memory only and thus we don't have to mark
* the inode dirty */
iinfo->i_lenExtents = inode->i_size;
brelse(epos.bh);
}
void udf_discard_prealloc(struct inode *inode)
{
struct extent_position epos = {};
struct extent_position prev_epos = {};
struct kernel_lb_addr eloc;
uint32_t elen;
uint64_t lbcount = 0;
int8_t etype = -1;
struct udf_inode_info *iinfo = UDF_I(inode);
int bsize = 1 << inode->i_blkbits;
if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB ||
ALIGN(inode->i_size, bsize) == ALIGN(iinfo->i_lenExtents, bsize))
return;
epos.block = iinfo->i_location;
/* Find the last extent in the file */
while (udf_next_aext(inode, &epos, &eloc, &elen, 0) != -1) {
brelse(prev_epos.bh);
prev_epos = epos;
if (prev_epos.bh)
get_bh(prev_epos.bh);
etype = udf_next_aext(inode, &epos, &eloc, &elen, 1);
lbcount += elen;
}
if (etype == (EXT_NOT_RECORDED_ALLOCATED >> 30)) {
lbcount -= elen;
udf_delete_aext(inode, prev_epos);
udf_free_blocks(inode->i_sb, inode, &eloc, 0,
DIV_ROUND_UP(elen, 1 << inode->i_blkbits));
}
/* This inode entry is in-memory only and thus we don't have to mark
* the inode dirty */
iinfo->i_lenExtents = lbcount;
brelse(epos.bh);
brelse(prev_epos.bh);
}
static void udf_update_alloc_ext_desc(struct inode *inode,
struct extent_position *epos,
u32 lenalloc)
{
struct super_block *sb = inode->i_sb;
struct udf_sb_info *sbi = UDF_SB(sb);
struct allocExtDesc *aed = (struct allocExtDesc *) (epos->bh->b_data);
int len = sizeof(struct allocExtDesc);
aed->lengthAllocDescs = cpu_to_le32(lenalloc);
if (!UDF_QUERY_FLAG(sb, UDF_FLAG_STRICT) || sbi->s_udfrev >= 0x0201)
len += lenalloc;
udf_update_tag(epos->bh->b_data, len);
mark_buffer_dirty_inode(epos->bh, inode);
}
/*
* Truncate extents of inode to inode->i_size. This function can be used only
* for making file shorter. For making file longer, udf_extend_file() has to
* be used.
*/
int udf_truncate_extents(struct inode *inode)
{
struct extent_position epos;
struct kernel_lb_addr eloc, neloc = {};
uint32_t elen, nelen = 0, indirect_ext_len = 0, lenalloc;
int8_t etype;
struct super_block *sb = inode->i_sb;
sector_t first_block = inode->i_size >> sb->s_blocksize_bits, offset;
loff_t byte_offset;
int adsize;
struct udf_inode_info *iinfo = UDF_I(inode);
if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT)
adsize = sizeof(struct short_ad);
else if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_LONG)
adsize = sizeof(struct long_ad);
else
BUG();
etype = inode_bmap(inode, first_block, &epos, &eloc, &elen, &offset);
byte_offset = (offset << sb->s_blocksize_bits) +
(inode->i_size & (sb->s_blocksize - 1));
if (etype == -1) {
/* We should extend the file? */
WARN_ON(byte_offset);
return 0;
}
epos.offset -= adsize;
extent_trunc(inode, &epos, &eloc, etype, elen, byte_offset);
epos.offset += adsize;
if (byte_offset)
lenalloc = epos.offset;
else
lenalloc = epos.offset - adsize;
if (!epos.bh)
lenalloc -= udf_file_entry_alloc_offset(inode);
else
lenalloc -= sizeof(struct allocExtDesc);
while ((etype = udf_current_aext(inode, &epos, &eloc,
&elen, 0)) != -1) {
if (etype == (EXT_NEXT_EXTENT_ALLOCDESCS >> 30)) {
udf_write_aext(inode, &epos, &neloc, nelen, 0);
if (indirect_ext_len) {
/* We managed to free all extents in the
* indirect extent - free it too */
BUG_ON(!epos.bh);
udf_free_blocks(sb, NULL, &epos.block,
0, indirect_ext_len);
} else if (!epos.bh) {
iinfo->i_lenAlloc = lenalloc;
mark_inode_dirty(inode);
} else
udf_update_alloc_ext_desc(inode,
&epos, lenalloc);
brelse(epos.bh);
epos.offset = sizeof(struct allocExtDesc);
epos.block = eloc;
epos.bh = sb_bread(sb,
udf_get_lb_pblock(sb, &eloc, 0));
/* Error reading indirect block? */
if (!epos.bh)
return -EIO;
if (elen)
indirect_ext_len =
(elen + sb->s_blocksize - 1) >>
sb->s_blocksize_bits;
else
indirect_ext_len = 1;
} else {
extent_trunc(inode, &epos, &eloc, etype, elen, 0);
epos.offset += adsize;
}
}
if (indirect_ext_len) {
BUG_ON(!epos.bh);
udf_free_blocks(sb, NULL, &epos.block, 0, indirect_ext_len);
} else if (!epos.bh) {
iinfo->i_lenAlloc = lenalloc;
mark_inode_dirty(inode);
} else
udf_update_alloc_ext_desc(inode, &epos, lenalloc);
iinfo->i_lenExtents = inode->i_size;
brelse(epos.bh);
return 0;
}
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