linux/fs/erofs/zmap.c
Gao Xiang 622ceaddb7 erofs: lzma compression support
Add MicroLZMA support in order to maximize compression ratios for
specific scenarios. For example, it's useful for low-end embedded
boards and as a secondary algorithm in a file for specific access
patterns.

MicroLZMA is a new container format for raw LZMA1, which was created
by Lasse Collin aiming to minimize old LZMA headers and get rid of
unnecessary EOPM (end of payload marker) as well as to enable
fixed-sized output compression, especially for 4KiB pclusters.

Similar to LZ4, inplace I/O approach is used to minimize runtime
memory footprint when dealing with I/O. Overlapped decompression is
handled with 1) bounced buffer for data under processing or 2) extra
short-lived pages from the on-stack pagepool which will be shared in
the same read request (128KiB for example).

Link: https://lore.kernel.org/r/20211010213145.17462-8-xiang@kernel.org
Acked-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
2021-10-19 23:44:30 +08:00

736 lines
19 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2018-2019 HUAWEI, Inc.
* https://www.huawei.com/
*/
#include "internal.h"
#include <asm/unaligned.h>
#include <trace/events/erofs.h>
int z_erofs_fill_inode(struct inode *inode)
{
struct erofs_inode *const vi = EROFS_I(inode);
struct erofs_sb_info *sbi = EROFS_SB(inode->i_sb);
if (!erofs_sb_has_big_pcluster(sbi) &&
vi->datalayout == EROFS_INODE_FLAT_COMPRESSION_LEGACY) {
vi->z_advise = 0;
vi->z_algorithmtype[0] = 0;
vi->z_algorithmtype[1] = 0;
vi->z_logical_clusterbits = LOG_BLOCK_SIZE;
set_bit(EROFS_I_Z_INITED_BIT, &vi->flags);
}
inode->i_mapping->a_ops = &z_erofs_aops;
return 0;
}
static int z_erofs_fill_inode_lazy(struct inode *inode)
{
struct erofs_inode *const vi = EROFS_I(inode);
struct super_block *const sb = inode->i_sb;
int err, headnr;
erofs_off_t pos;
struct page *page;
void *kaddr;
struct z_erofs_map_header *h;
if (test_bit(EROFS_I_Z_INITED_BIT, &vi->flags)) {
/*
* paired with smp_mb() at the end of the function to ensure
* fields will only be observed after the bit is set.
*/
smp_mb();
return 0;
}
if (wait_on_bit_lock(&vi->flags, EROFS_I_BL_Z_BIT, TASK_KILLABLE))
return -ERESTARTSYS;
err = 0;
if (test_bit(EROFS_I_Z_INITED_BIT, &vi->flags))
goto out_unlock;
DBG_BUGON(!erofs_sb_has_big_pcluster(EROFS_SB(sb)) &&
vi->datalayout == EROFS_INODE_FLAT_COMPRESSION_LEGACY);
pos = ALIGN(iloc(EROFS_SB(sb), vi->nid) + vi->inode_isize +
vi->xattr_isize, 8);
page = erofs_get_meta_page(sb, erofs_blknr(pos));
if (IS_ERR(page)) {
err = PTR_ERR(page);
goto out_unlock;
}
kaddr = kmap_atomic(page);
h = kaddr + erofs_blkoff(pos);
vi->z_advise = le16_to_cpu(h->h_advise);
vi->z_algorithmtype[0] = h->h_algorithmtype & 15;
vi->z_algorithmtype[1] = h->h_algorithmtype >> 4;
headnr = 0;
if (vi->z_algorithmtype[0] >= Z_EROFS_COMPRESSION_MAX ||
vi->z_algorithmtype[++headnr] >= Z_EROFS_COMPRESSION_MAX) {
erofs_err(sb, "unknown HEAD%u format %u for nid %llu, please upgrade kernel",
headnr + 1, vi->z_algorithmtype[headnr], vi->nid);
err = -EOPNOTSUPP;
goto unmap_done;
}
vi->z_logical_clusterbits = LOG_BLOCK_SIZE + (h->h_clusterbits & 7);
if (!erofs_sb_has_big_pcluster(EROFS_SB(sb)) &&
vi->z_advise & (Z_EROFS_ADVISE_BIG_PCLUSTER_1 |
Z_EROFS_ADVISE_BIG_PCLUSTER_2)) {
erofs_err(sb, "per-inode big pcluster without sb feature for nid %llu",
vi->nid);
err = -EFSCORRUPTED;
goto unmap_done;
}
if (vi->datalayout == EROFS_INODE_FLAT_COMPRESSION &&
!(vi->z_advise & Z_EROFS_ADVISE_BIG_PCLUSTER_1) ^
!(vi->z_advise & Z_EROFS_ADVISE_BIG_PCLUSTER_2)) {
erofs_err(sb, "big pcluster head1/2 of compact indexes should be consistent for nid %llu",
vi->nid);
err = -EFSCORRUPTED;
goto unmap_done;
}
/* paired with smp_mb() at the beginning of the function */
smp_mb();
set_bit(EROFS_I_Z_INITED_BIT, &vi->flags);
unmap_done:
kunmap_atomic(kaddr);
unlock_page(page);
put_page(page);
out_unlock:
clear_and_wake_up_bit(EROFS_I_BL_Z_BIT, &vi->flags);
return err;
}
struct z_erofs_maprecorder {
struct inode *inode;
struct erofs_map_blocks *map;
void *kaddr;
unsigned long lcn;
/* compression extent information gathered */
u8 type, headtype;
u16 clusterofs;
u16 delta[2];
erofs_blk_t pblk, compressedlcs;
};
static int z_erofs_reload_indexes(struct z_erofs_maprecorder *m,
erofs_blk_t eblk)
{
struct super_block *const sb = m->inode->i_sb;
struct erofs_map_blocks *const map = m->map;
struct page *mpage = map->mpage;
if (mpage) {
if (mpage->index == eblk) {
if (!m->kaddr)
m->kaddr = kmap_atomic(mpage);
return 0;
}
if (m->kaddr) {
kunmap_atomic(m->kaddr);
m->kaddr = NULL;
}
put_page(mpage);
}
mpage = erofs_get_meta_page(sb, eblk);
if (IS_ERR(mpage)) {
map->mpage = NULL;
return PTR_ERR(mpage);
}
m->kaddr = kmap_atomic(mpage);
unlock_page(mpage);
map->mpage = mpage;
return 0;
}
static int legacy_load_cluster_from_disk(struct z_erofs_maprecorder *m,
unsigned long lcn)
{
struct inode *const inode = m->inode;
struct erofs_inode *const vi = EROFS_I(inode);
const erofs_off_t ibase = iloc(EROFS_I_SB(inode), vi->nid);
const erofs_off_t pos =
Z_EROFS_VLE_LEGACY_INDEX_ALIGN(ibase + vi->inode_isize +
vi->xattr_isize) +
lcn * sizeof(struct z_erofs_vle_decompressed_index);
struct z_erofs_vle_decompressed_index *di;
unsigned int advise, type;
int err;
err = z_erofs_reload_indexes(m, erofs_blknr(pos));
if (err)
return err;
m->lcn = lcn;
di = m->kaddr + erofs_blkoff(pos);
advise = le16_to_cpu(di->di_advise);
type = (advise >> Z_EROFS_VLE_DI_CLUSTER_TYPE_BIT) &
((1 << Z_EROFS_VLE_DI_CLUSTER_TYPE_BITS) - 1);
switch (type) {
case Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD:
m->clusterofs = 1 << vi->z_logical_clusterbits;
m->delta[0] = le16_to_cpu(di->di_u.delta[0]);
if (m->delta[0] & Z_EROFS_VLE_DI_D0_CBLKCNT) {
if (!(vi->z_advise & (Z_EROFS_ADVISE_BIG_PCLUSTER_1 |
Z_EROFS_ADVISE_BIG_PCLUSTER_2))) {
DBG_BUGON(1);
return -EFSCORRUPTED;
}
m->compressedlcs = m->delta[0] &
~Z_EROFS_VLE_DI_D0_CBLKCNT;
m->delta[0] = 1;
}
m->delta[1] = le16_to_cpu(di->di_u.delta[1]);
break;
case Z_EROFS_VLE_CLUSTER_TYPE_PLAIN:
case Z_EROFS_VLE_CLUSTER_TYPE_HEAD1:
case Z_EROFS_VLE_CLUSTER_TYPE_HEAD2:
m->clusterofs = le16_to_cpu(di->di_clusterofs);
m->pblk = le32_to_cpu(di->di_u.blkaddr);
break;
default:
DBG_BUGON(1);
return -EOPNOTSUPP;
}
m->type = type;
return 0;
}
static unsigned int decode_compactedbits(unsigned int lobits,
unsigned int lomask,
u8 *in, unsigned int pos, u8 *type)
{
const unsigned int v = get_unaligned_le32(in + pos / 8) >> (pos & 7);
const unsigned int lo = v & lomask;
*type = (v >> lobits) & 3;
return lo;
}
static int get_compacted_la_distance(unsigned int lclusterbits,
unsigned int encodebits,
unsigned int vcnt, u8 *in, int i)
{
const unsigned int lomask = (1 << lclusterbits) - 1;
unsigned int lo, d1 = 0;
u8 type;
DBG_BUGON(i >= vcnt);
do {
lo = decode_compactedbits(lclusterbits, lomask,
in, encodebits * i, &type);
if (type != Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD)
return d1;
++d1;
} while (++i < vcnt);
/* vcnt - 1 (Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD) item */
if (!(lo & Z_EROFS_VLE_DI_D0_CBLKCNT))
d1 += lo - 1;
return d1;
}
static int unpack_compacted_index(struct z_erofs_maprecorder *m,
unsigned int amortizedshift,
unsigned int eofs, bool lookahead)
{
struct erofs_inode *const vi = EROFS_I(m->inode);
const unsigned int lclusterbits = vi->z_logical_clusterbits;
const unsigned int lomask = (1 << lclusterbits) - 1;
unsigned int vcnt, base, lo, encodebits, nblk;
int i;
u8 *in, type;
bool big_pcluster;
if (1 << amortizedshift == 4)
vcnt = 2;
else if (1 << amortizedshift == 2 && lclusterbits == 12)
vcnt = 16;
else
return -EOPNOTSUPP;
big_pcluster = vi->z_advise & Z_EROFS_ADVISE_BIG_PCLUSTER_1;
encodebits = ((vcnt << amortizedshift) - sizeof(__le32)) * 8 / vcnt;
base = round_down(eofs, vcnt << amortizedshift);
in = m->kaddr + base;
i = (eofs - base) >> amortizedshift;
lo = decode_compactedbits(lclusterbits, lomask,
in, encodebits * i, &type);
m->type = type;
if (type == Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD) {
m->clusterofs = 1 << lclusterbits;
/* figure out lookahead_distance: delta[1] if needed */
if (lookahead)
m->delta[1] = get_compacted_la_distance(lclusterbits,
encodebits, vcnt, in, i);
if (lo & Z_EROFS_VLE_DI_D0_CBLKCNT) {
if (!big_pcluster) {
DBG_BUGON(1);
return -EFSCORRUPTED;
}
m->compressedlcs = lo & ~Z_EROFS_VLE_DI_D0_CBLKCNT;
m->delta[0] = 1;
return 0;
} else if (i + 1 != (int)vcnt) {
m->delta[0] = lo;
return 0;
}
/*
* since the last lcluster in the pack is special,
* of which lo saves delta[1] rather than delta[0].
* Hence, get delta[0] by the previous lcluster indirectly.
*/
lo = decode_compactedbits(lclusterbits, lomask,
in, encodebits * (i - 1), &type);
if (type != Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD)
lo = 0;
else if (lo & Z_EROFS_VLE_DI_D0_CBLKCNT)
lo = 1;
m->delta[0] = lo + 1;
return 0;
}
m->clusterofs = lo;
m->delta[0] = 0;
/* figout out blkaddr (pblk) for HEAD lclusters */
if (!big_pcluster) {
nblk = 1;
while (i > 0) {
--i;
lo = decode_compactedbits(lclusterbits, lomask,
in, encodebits * i, &type);
if (type == Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD)
i -= lo;
if (i >= 0)
++nblk;
}
} else {
nblk = 0;
while (i > 0) {
--i;
lo = decode_compactedbits(lclusterbits, lomask,
in, encodebits * i, &type);
if (type == Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD) {
if (lo & Z_EROFS_VLE_DI_D0_CBLKCNT) {
--i;
nblk += lo & ~Z_EROFS_VLE_DI_D0_CBLKCNT;
continue;
}
/* bigpcluster shouldn't have plain d0 == 1 */
if (lo <= 1) {
DBG_BUGON(1);
return -EFSCORRUPTED;
}
i -= lo - 2;
continue;
}
++nblk;
}
}
in += (vcnt << amortizedshift) - sizeof(__le32);
m->pblk = le32_to_cpu(*(__le32 *)in) + nblk;
return 0;
}
static int compacted_load_cluster_from_disk(struct z_erofs_maprecorder *m,
unsigned long lcn, bool lookahead)
{
struct inode *const inode = m->inode;
struct erofs_inode *const vi = EROFS_I(inode);
const unsigned int lclusterbits = vi->z_logical_clusterbits;
const erofs_off_t ebase = ALIGN(iloc(EROFS_I_SB(inode), vi->nid) +
vi->inode_isize + vi->xattr_isize, 8) +
sizeof(struct z_erofs_map_header);
const unsigned int totalidx = DIV_ROUND_UP(inode->i_size, EROFS_BLKSIZ);
unsigned int compacted_4b_initial, compacted_2b;
unsigned int amortizedshift;
erofs_off_t pos;
int err;
if (lclusterbits != 12)
return -EOPNOTSUPP;
if (lcn >= totalidx)
return -EINVAL;
m->lcn = lcn;
/* used to align to 32-byte (compacted_2b) alignment */
compacted_4b_initial = (32 - ebase % 32) / 4;
if (compacted_4b_initial == 32 / 4)
compacted_4b_initial = 0;
if ((vi->z_advise & Z_EROFS_ADVISE_COMPACTED_2B) &&
compacted_4b_initial < totalidx)
compacted_2b = rounddown(totalidx - compacted_4b_initial, 16);
else
compacted_2b = 0;
pos = ebase;
if (lcn < compacted_4b_initial) {
amortizedshift = 2;
goto out;
}
pos += compacted_4b_initial * 4;
lcn -= compacted_4b_initial;
if (lcn < compacted_2b) {
amortizedshift = 1;
goto out;
}
pos += compacted_2b * 2;
lcn -= compacted_2b;
amortizedshift = 2;
out:
pos += lcn * (1 << amortizedshift);
err = z_erofs_reload_indexes(m, erofs_blknr(pos));
if (err)
return err;
return unpack_compacted_index(m, amortizedshift, erofs_blkoff(pos),
lookahead);
}
static int z_erofs_load_cluster_from_disk(struct z_erofs_maprecorder *m,
unsigned int lcn, bool lookahead)
{
const unsigned int datamode = EROFS_I(m->inode)->datalayout;
if (datamode == EROFS_INODE_FLAT_COMPRESSION_LEGACY)
return legacy_load_cluster_from_disk(m, lcn);
if (datamode == EROFS_INODE_FLAT_COMPRESSION)
return compacted_load_cluster_from_disk(m, lcn, lookahead);
return -EINVAL;
}
static int z_erofs_extent_lookback(struct z_erofs_maprecorder *m,
unsigned int lookback_distance)
{
struct erofs_inode *const vi = EROFS_I(m->inode);
struct erofs_map_blocks *const map = m->map;
const unsigned int lclusterbits = vi->z_logical_clusterbits;
unsigned long lcn = m->lcn;
int err;
if (lcn < lookback_distance) {
erofs_err(m->inode->i_sb,
"bogus lookback distance @ nid %llu", vi->nid);
DBG_BUGON(1);
return -EFSCORRUPTED;
}
/* load extent head logical cluster if needed */
lcn -= lookback_distance;
err = z_erofs_load_cluster_from_disk(m, lcn, false);
if (err)
return err;
switch (m->type) {
case Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD:
if (!m->delta[0]) {
erofs_err(m->inode->i_sb,
"invalid lookback distance 0 @ nid %llu",
vi->nid);
DBG_BUGON(1);
return -EFSCORRUPTED;
}
return z_erofs_extent_lookback(m, m->delta[0]);
case Z_EROFS_VLE_CLUSTER_TYPE_PLAIN:
case Z_EROFS_VLE_CLUSTER_TYPE_HEAD1:
case Z_EROFS_VLE_CLUSTER_TYPE_HEAD2:
m->headtype = m->type;
map->m_la = (lcn << lclusterbits) | m->clusterofs;
break;
default:
erofs_err(m->inode->i_sb,
"unknown type %u @ lcn %lu of nid %llu",
m->type, lcn, vi->nid);
DBG_BUGON(1);
return -EOPNOTSUPP;
}
return 0;
}
static int z_erofs_get_extent_compressedlen(struct z_erofs_maprecorder *m,
unsigned int initial_lcn)
{
struct erofs_inode *const vi = EROFS_I(m->inode);
struct erofs_map_blocks *const map = m->map;
const unsigned int lclusterbits = vi->z_logical_clusterbits;
unsigned long lcn;
int err;
DBG_BUGON(m->type != Z_EROFS_VLE_CLUSTER_TYPE_PLAIN &&
m->type != Z_EROFS_VLE_CLUSTER_TYPE_HEAD1 &&
m->type != Z_EROFS_VLE_CLUSTER_TYPE_HEAD2);
DBG_BUGON(m->type != m->headtype);
if (m->headtype == Z_EROFS_VLE_CLUSTER_TYPE_PLAIN ||
((m->headtype == Z_EROFS_VLE_CLUSTER_TYPE_HEAD1) &&
!(vi->z_advise & Z_EROFS_ADVISE_BIG_PCLUSTER_1)) ||
((m->headtype == Z_EROFS_VLE_CLUSTER_TYPE_HEAD2) &&
!(vi->z_advise & Z_EROFS_ADVISE_BIG_PCLUSTER_2))) {
map->m_plen = 1 << lclusterbits;
return 0;
}
lcn = m->lcn + 1;
if (m->compressedlcs)
goto out;
err = z_erofs_load_cluster_from_disk(m, lcn, false);
if (err)
return err;
/*
* If the 1st NONHEAD lcluster has already been handled initially w/o
* valid compressedlcs, which means at least it mustn't be CBLKCNT, or
* an internal implemenatation error is detected.
*
* The following code can also handle it properly anyway, but let's
* BUG_ON in the debugging mode only for developers to notice that.
*/
DBG_BUGON(lcn == initial_lcn &&
m->type == Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD);
switch (m->type) {
case Z_EROFS_VLE_CLUSTER_TYPE_PLAIN:
case Z_EROFS_VLE_CLUSTER_TYPE_HEAD1:
case Z_EROFS_VLE_CLUSTER_TYPE_HEAD2:
/*
* if the 1st NONHEAD lcluster is actually PLAIN or HEAD type
* rather than CBLKCNT, it's a 1 lcluster-sized pcluster.
*/
m->compressedlcs = 1;
break;
case Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD:
if (m->delta[0] != 1)
goto err_bonus_cblkcnt;
if (m->compressedlcs)
break;
fallthrough;
default:
erofs_err(m->inode->i_sb,
"cannot found CBLKCNT @ lcn %lu of nid %llu",
lcn, vi->nid);
DBG_BUGON(1);
return -EFSCORRUPTED;
}
out:
map->m_plen = m->compressedlcs << lclusterbits;
return 0;
err_bonus_cblkcnt:
erofs_err(m->inode->i_sb,
"bogus CBLKCNT @ lcn %lu of nid %llu",
lcn, vi->nid);
DBG_BUGON(1);
return -EFSCORRUPTED;
}
static int z_erofs_get_extent_decompressedlen(struct z_erofs_maprecorder *m)
{
struct inode *inode = m->inode;
struct erofs_inode *vi = EROFS_I(inode);
struct erofs_map_blocks *map = m->map;
unsigned int lclusterbits = vi->z_logical_clusterbits;
u64 lcn = m->lcn, headlcn = map->m_la >> lclusterbits;
int err;
do {
/* handle the last EOF pcluster (no next HEAD lcluster) */
if ((lcn << lclusterbits) >= inode->i_size) {
map->m_llen = inode->i_size - map->m_la;
return 0;
}
err = z_erofs_load_cluster_from_disk(m, lcn, true);
if (err)
return err;
if (m->type == Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD) {
DBG_BUGON(!m->delta[1] &&
m->clusterofs != 1 << lclusterbits);
} else if (m->type == Z_EROFS_VLE_CLUSTER_TYPE_PLAIN ||
m->type == Z_EROFS_VLE_CLUSTER_TYPE_HEAD1 ||
m->type == Z_EROFS_VLE_CLUSTER_TYPE_HEAD2) {
/* go on until the next HEAD lcluster */
if (lcn != headlcn)
break;
m->delta[1] = 1;
} else {
erofs_err(inode->i_sb, "unknown type %u @ lcn %llu of nid %llu",
m->type, lcn, vi->nid);
DBG_BUGON(1);
return -EOPNOTSUPP;
}
lcn += m->delta[1];
} while (m->delta[1]);
map->m_llen = (lcn << lclusterbits) + m->clusterofs - map->m_la;
return 0;
}
int z_erofs_map_blocks_iter(struct inode *inode,
struct erofs_map_blocks *map,
int flags)
{
struct erofs_inode *const vi = EROFS_I(inode);
struct z_erofs_maprecorder m = {
.inode = inode,
.map = map,
};
int err = 0;
unsigned int lclusterbits, endoff;
unsigned long initial_lcn;
unsigned long long ofs, end;
trace_z_erofs_map_blocks_iter_enter(inode, map, flags);
/* when trying to read beyond EOF, leave it unmapped */
if (map->m_la >= inode->i_size) {
map->m_llen = map->m_la + 1 - inode->i_size;
map->m_la = inode->i_size;
map->m_flags = 0;
goto out;
}
err = z_erofs_fill_inode_lazy(inode);
if (err)
goto out;
lclusterbits = vi->z_logical_clusterbits;
ofs = map->m_la;
initial_lcn = ofs >> lclusterbits;
endoff = ofs & ((1 << lclusterbits) - 1);
err = z_erofs_load_cluster_from_disk(&m, initial_lcn, false);
if (err)
goto unmap_out;
map->m_flags = EROFS_MAP_MAPPED | EROFS_MAP_ENCODED;
end = (m.lcn + 1ULL) << lclusterbits;
switch (m.type) {
case Z_EROFS_VLE_CLUSTER_TYPE_PLAIN:
case Z_EROFS_VLE_CLUSTER_TYPE_HEAD1:
case Z_EROFS_VLE_CLUSTER_TYPE_HEAD2:
if (endoff >= m.clusterofs) {
m.headtype = m.type;
map->m_la = (m.lcn << lclusterbits) | m.clusterofs;
break;
}
/* m.lcn should be >= 1 if endoff < m.clusterofs */
if (!m.lcn) {
erofs_err(inode->i_sb,
"invalid logical cluster 0 at nid %llu",
vi->nid);
err = -EFSCORRUPTED;
goto unmap_out;
}
end = (m.lcn << lclusterbits) | m.clusterofs;
map->m_flags |= EROFS_MAP_FULL_MAPPED;
m.delta[0] = 1;
fallthrough;
case Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD:
/* get the corresponding first chunk */
err = z_erofs_extent_lookback(&m, m.delta[0]);
if (err)
goto unmap_out;
break;
default:
erofs_err(inode->i_sb,
"unknown type %u @ offset %llu of nid %llu",
m.type, ofs, vi->nid);
err = -EOPNOTSUPP;
goto unmap_out;
}
map->m_llen = end - map->m_la;
map->m_pa = blknr_to_addr(m.pblk);
err = z_erofs_get_extent_compressedlen(&m, initial_lcn);
if (err)
goto out;
if (m.headtype == Z_EROFS_VLE_CLUSTER_TYPE_PLAIN)
map->m_algorithmformat = Z_EROFS_COMPRESSION_SHIFTED;
else if (m.headtype == Z_EROFS_VLE_CLUSTER_TYPE_HEAD2)
map->m_algorithmformat = vi->z_algorithmtype[1];
else
map->m_algorithmformat = vi->z_algorithmtype[0];
if ((flags & EROFS_GET_BLOCKS_FIEMAP) ||
((flags & EROFS_GET_BLOCKS_READMORE) &&
map->m_algorithmformat == Z_EROFS_COMPRESSION_LZMA &&
map->m_llen >= EROFS_BLKSIZ)) {
err = z_erofs_get_extent_decompressedlen(&m);
if (!err)
map->m_flags |= EROFS_MAP_FULL_MAPPED;
}
unmap_out:
if (m.kaddr)
kunmap_atomic(m.kaddr);
out:
erofs_dbg("%s, m_la %llu m_pa %llu m_llen %llu m_plen %llu m_flags 0%o",
__func__, map->m_la, map->m_pa,
map->m_llen, map->m_plen, map->m_flags);
trace_z_erofs_map_blocks_iter_exit(inode, map, flags, err);
/* aggressively BUG_ON iff CONFIG_EROFS_FS_DEBUG is on */
DBG_BUGON(err < 0 && err != -ENOMEM);
return err;
}
static int z_erofs_iomap_begin_report(struct inode *inode, loff_t offset,
loff_t length, unsigned int flags,
struct iomap *iomap, struct iomap *srcmap)
{
int ret;
struct erofs_map_blocks map = { .m_la = offset };
ret = z_erofs_map_blocks_iter(inode, &map, EROFS_GET_BLOCKS_FIEMAP);
if (map.mpage)
put_page(map.mpage);
if (ret < 0)
return ret;
iomap->bdev = inode->i_sb->s_bdev;
iomap->offset = map.m_la;
iomap->length = map.m_llen;
if (map.m_flags & EROFS_MAP_MAPPED) {
iomap->type = IOMAP_MAPPED;
iomap->addr = map.m_pa;
} else {
iomap->type = IOMAP_HOLE;
iomap->addr = IOMAP_NULL_ADDR;
/*
* No strict rule how to describe extents for post EOF, yet
* we need do like below. Otherwise, iomap itself will get
* into an endless loop on post EOF.
*/
if (iomap->offset >= inode->i_size)
iomap->length = length + map.m_la - offset;
}
iomap->flags = 0;
return 0;
}
const struct iomap_ops z_erofs_iomap_report_ops = {
.iomap_begin = z_erofs_iomap_begin_report,
};