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linux-next/fs/erofs/zmap.c
Yue Hu c40dd3ca2a erofs: clear compacted_2b if compacted_4b_initial > totalidx 
Currently, the whole indexes will only be compacted 4B if
compacted_4b_initial > totalidx. So, the calculated compacted_2b
is worthless for that case. It may waste CPU resources.

No need to update compacted_4b_initial as mkfs since it's used to
fulfill the alignment of the 1st compacted_2b pack and would handle
the case above.

We also need to clarify compacted_4b_end here. It's used for the
last lclusters which aren't fitted in the previous compacted_2b
packs.

Some messages are from Xiang.

Link: https://lore.kernel.org/r/20210914035915.1190-1-zbestahu@gmail.com
Signed-off-by: Yue Hu <huyue2@yulong.com>
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Reviewed-by: Chao Yu <chao@kernel.org>
[ Gao Xiang: it's enough to use "compacted_4b_initial < totalidx". ]
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
2021-09-23 23:23:04 +08:00

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// 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;
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;
if (vi->z_algorithmtype[0] >= Z_EROFS_COMPRESSION_MAX) {
erofs_err(sb, "unknown compression format %u for nid %llu, please upgrade kernel",
vi->z_algorithmtype[0], 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;
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)) {
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_HEAD:
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:
map->m_flags &= ~EROFS_MAP_ZIPPED;
fallthrough;
case Z_EROFS_VLE_CLUSTER_TYPE_HEAD:
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_HEAD);
if (!(map->m_flags & EROFS_MAP_ZIPPED) ||
!(vi->z_advise & Z_EROFS_ADVISE_BIG_PCLUSTER_1)) {
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_HEAD:
/*
* 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_HEAD) {
/* 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_ZIPPED; /* by default, compressed */
end = (m.lcn + 1ULL) << lclusterbits;
switch (m.type) {
case Z_EROFS_VLE_CLUSTER_TYPE_PLAIN:
if (endoff >= m.clusterofs)
map->m_flags &= ~EROFS_MAP_ZIPPED;
fallthrough;
case Z_EROFS_VLE_CLUSTER_TYPE_HEAD:
if (endoff >= m.clusterofs) {
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);
map->m_flags |= EROFS_MAP_MAPPED;
err = z_erofs_get_extent_compressedlen(&m, initial_lcn);
if (err)
goto out;
if (flags & EROFS_GET_BLOCKS_FIEMAP) {
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,
};
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