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staging: erofs: add compacted compression indexes support 

This patch aims at compacted compression indexes:
 1) cleanup z_erofs_map_blocks_iter and move into zmap.c;
 2) add compacted 4/2B decoding support.

On kirin980 platform, sequential read is increased about
6% (725MiB/s -> 770MiB/s) on enwik9 dataset if compacted 2B
feature is enabled.

Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Gao Xiang 2019-06-24 15:22:52 +08:00 committed by Greg Kroah-Hartman
parent ec8c244205
commit 152a333a58
5 changed files with 480 additions and 295 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
drivers/staging/erofs/Makefile
View File

@ -9,5 +9,5 @@ obj-$(CONFIG_EROFS_FS) += erofs.o
ccflags-y += -I $(srctree)/$(src)/include
erofs-objs := super.o inode.o data.o namei.o dir.o utils.o
erofs-$(CONFIG_EROFS_FS_XATTR) += xattr.o
erofs-$(CONFIG_EROFS_FS_ZIP) += unzip_vle.o unzip_vle_lz4.o
erofs-$(CONFIG_EROFS_FS_ZIP) += unzip_vle.o unzip_vle_lz4.o zmap.o

7
drivers/staging/erofs/inode.c
View File

@ -210,12 +210,7 @@ static int fill_inode(struct inode *inode, int isdir)
}
if (is_inode_layout_compression(inode)) {
#ifdef CONFIG_EROFS_FS_ZIP
inode->i_mapping->a_ops =
&z_erofs_vle_normalaccess_aops;
#else
err = -ENOTSUPP;
#endif
err = z_erofs_fill_inode(inode);
goto out_unlock;
}

18
drivers/staging/erofs/internal.h
View File

@ -339,9 +339,11 @@ static inline erofs_off_t iloc(struct erofs_sb_info *sbi, erofs_nid_t nid)
/* atomic flag definitions */
#define EROFS_V_EA_INITED_BIT 0
#define EROFS_V_Z_INITED_BIT 1
/* bitlock definitions (arranged in reverse order) */
#define EROFS_V_BL_XATTR_BIT (BITS_PER_LONG - 1)
#define EROFS_V_BL_Z_BIT (BITS_PER_LONG - 2)
struct erofs_vnode {
erofs_nid_t nid;
@ -356,8 +358,17 @@ struct erofs_vnode {
unsigned xattr_shared_count;
unsigned *xattr_shared_xattrs;
erofs_blk_t raw_blkaddr;
union {
erofs_blk_t raw_blkaddr;
#ifdef CONFIG_EROFS_FS_ZIP
struct {
unsigned short z_advise;
unsigned char z_algorithmtype[2];
unsigned char z_logical_clusterbits;
unsigned char z_physical_clusterbits[2];
};
#endif
};
/* the corresponding vfs inode */
struct inode vfs_inode;
};
@ -447,11 +458,14 @@ struct erofs_map_blocks {
/* Flags used by erofs_map_blocks() */
#define EROFS_GET_BLOCKS_RAW 0x0001
/* zmap.c */
#ifdef CONFIG_EROFS_FS_ZIP
int z_erofs_fill_inode(struct inode *inode);
int z_erofs_map_blocks_iter(struct inode *inode,
struct erofs_map_blocks *map,
int flags);
#else
static inline int z_erofs_fill_inode(struct inode *inode) { return -ENOTSUPP; }
static inline int z_erofs_map_blocks_iter(struct inode *inode,
struct erofs_map_blocks *map,
int flags)

286
drivers/staging/erofs/unzip_vle.c
View File

@ -1600,289 +1600,3 @@ const struct address_space_operations z_erofs_vle_normalaccess_aops = {
.readpages = z_erofs_vle_normalaccess_readpages,
};
/*
* Variable-sized Logical Extent (Fixed Physical Cluster) Compression Mode
* ---
* VLE compression mode attempts to compress a number of logical data into
* a physical cluster with a fixed size.
* VLE compression mode uses "struct z_erofs_vle_decompressed_index".
*/
#define __vle_cluster_advise(x, bit, bits) \
((le16_to_cpu(x) >> (bit)) & ((1 << (bits)) - 1))
#define __vle_cluster_type(advise) __vle_cluster_advise(advise, \
Z_EROFS_VLE_DI_CLUSTER_TYPE_BIT, Z_EROFS_VLE_DI_CLUSTER_TYPE_BITS)
#define vle_cluster_type(di) \
__vle_cluster_type((di)->di_advise)
static int
vle_decompressed_index_clusterofs(unsigned int *clusterofs,
unsigned int clustersize,
struct z_erofs_vle_decompressed_index *di)
{
switch (vle_cluster_type(di)) {
case Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD:
*clusterofs = clustersize;
break;
case Z_EROFS_VLE_CLUSTER_TYPE_PLAIN:
case Z_EROFS_VLE_CLUSTER_TYPE_HEAD:
*clusterofs = le16_to_cpu(di->di_clusterofs);
break;
default:
DBG_BUGON(1);
return -EIO;
}
return 0;
}
static inline erofs_blk_t
vle_extent_blkaddr(struct inode *inode, pgoff_t index)
{
struct erofs_sb_info *sbi = EROFS_I_SB(inode);
struct erofs_vnode *vi = EROFS_V(inode);
unsigned int ofs = Z_EROFS_VLE_LEGACY_INDEX_ALIGN(vi->inode_isize +
vi->xattr_isize) +
index * sizeof(struct z_erofs_vle_decompressed_index);
return erofs_blknr(iloc(sbi, vi->nid) + ofs);
}
static inline unsigned int
vle_extent_blkoff(struct inode *inode, pgoff_t index)
{
struct erofs_sb_info *sbi = EROFS_I_SB(inode);
struct erofs_vnode *vi = EROFS_V(inode);
unsigned int ofs = Z_EROFS_VLE_LEGACY_INDEX_ALIGN(vi->inode_isize +
vi->xattr_isize) +
index * sizeof(struct z_erofs_vle_decompressed_index);
return erofs_blkoff(iloc(sbi, vi->nid) + ofs);
}
struct vle_map_blocks_iter_ctx {
struct inode *inode;
struct super_block *sb;
unsigned int clusterbits;
struct page **mpage_ret;
void **kaddr_ret;
};
static int
vle_get_logical_extent_head(const struct vle_map_blocks_iter_ctx *ctx,
unsigned int lcn, /* logical cluster number */
unsigned long long *ofs,
erofs_blk_t *pblk,
unsigned int *flags)
{
const unsigned int clustersize = 1 << ctx->clusterbits;
const erofs_blk_t mblk = vle_extent_blkaddr(ctx->inode, lcn);
struct page *mpage = *ctx->mpage_ret; /* extent metapage */
struct z_erofs_vle_decompressed_index *di;
unsigned int cluster_type, delta0;
if (mpage->index != mblk) {
kunmap_atomic(*ctx->kaddr_ret);
unlock_page(mpage);
put_page(mpage);
mpage = erofs_get_meta_page(ctx->sb, mblk, false);
if (IS_ERR(mpage)) {
*ctx->mpage_ret = NULL;
return PTR_ERR(mpage);
}
*ctx->mpage_ret = mpage;
*ctx->kaddr_ret = kmap_atomic(mpage);
}
di = *ctx->kaddr_ret + vle_extent_blkoff(ctx->inode, lcn);
cluster_type = vle_cluster_type(di);
switch (cluster_type) {
case Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD:
delta0 = le16_to_cpu(di->di_u.delta[0]);
if (unlikely(!delta0 || delta0 > lcn)) {
errln("invalid NONHEAD dl0 %u at lcn %u of nid %llu",
delta0, lcn, EROFS_V(ctx->inode)->nid);
DBG_BUGON(1);
return -EIO;
}
return vle_get_logical_extent_head(ctx,
lcn - delta0, ofs, pblk, flags);
case Z_EROFS_VLE_CLUSTER_TYPE_PLAIN:
*flags ^= EROFS_MAP_ZIPPED;
/* fallthrough */
case Z_EROFS_VLE_CLUSTER_TYPE_HEAD:
/* clustersize should be a power of two */
*ofs = ((u64)lcn << ctx->clusterbits) +
(le16_to_cpu(di->di_clusterofs) & (clustersize - 1));
*pblk = le32_to_cpu(di->di_u.blkaddr);
break;
default:
errln("unknown cluster type %u at lcn %u of nid %llu",
cluster_type, lcn, EROFS_V(ctx->inode)->nid);
DBG_BUGON(1);
return -EIO;
}
return 0;
}
int z_erofs_map_blocks_iter(struct inode *inode,
struct erofs_map_blocks *map,
int flags)
{
void *kaddr;
const struct vle_map_blocks_iter_ctx ctx = {
.inode = inode,
.sb = inode->i_sb,
.clusterbits = EROFS_I_SB(inode)->clusterbits,
.mpage_ret = &map->mpage,
.kaddr_ret = &kaddr
};
const unsigned int clustersize = 1 << ctx.clusterbits;
/* if both m_(l,p)len are 0, regularize l_lblk, l_lofs, etc... */
const bool initial = !map->m_llen;
/* logicial extent (start, end) offset */
unsigned long long ofs, end;
unsigned int lcn;
u32 ofs_rem;
/* initialize `pblk' to keep gcc from printing foolish warnings */
erofs_blk_t mblk, pblk = 0;
struct page *mpage = map->mpage;
struct z_erofs_vle_decompressed_index *di;
unsigned int cluster_type, logical_cluster_ofs;
int err = 0;
trace_z_erofs_map_blocks_iter_enter(inode, map, flags);
/* when trying to read beyond EOF, leave it unmapped */
if (unlikely(map->m_la >= inode->i_size)) {
DBG_BUGON(!initial);
map->m_llen = map->m_la + 1 - inode->i_size;
map->m_la = inode->i_size;
map->m_flags = 0;
goto out;
}
debugln("%s, m_la %llu m_llen %llu --- start", __func__,
map->m_la, map->m_llen);
ofs = map->m_la + map->m_llen;
/* clustersize should be power of two */
lcn = ofs >> ctx.clusterbits;
ofs_rem = ofs & (clustersize - 1);
mblk = vle_extent_blkaddr(inode, lcn);
if (!mpage || mpage->index != mblk) {
if (mpage)
put_page(mpage);
mpage = erofs_get_meta_page(ctx.sb, mblk, false);
if (IS_ERR(mpage)) {
err = PTR_ERR(mpage);
goto out;
}
map->mpage = mpage;
} else {
lock_page(mpage);
DBG_BUGON(!PageUptodate(mpage));
}
kaddr = kmap_atomic(mpage);
di = kaddr + vle_extent_blkoff(inode, lcn);
debugln("%s, lcn %u mblk %u e_blkoff %u", __func__, lcn,
mblk, vle_extent_blkoff(inode, lcn));
err = vle_decompressed_index_clusterofs(&logical_cluster_ofs,
clustersize, di);
if (unlikely(err))
goto unmap_out;
if (!initial) {
/* [walking mode] 'map' has been already initialized */
map->m_llen += logical_cluster_ofs;
goto unmap_out;
}
/* by default, compressed */
map->m_flags |= EROFS_MAP_ZIPPED;
end = ((u64)lcn + 1) * clustersize;
cluster_type = vle_cluster_type(di);
switch (cluster_type) {
case Z_EROFS_VLE_CLUSTER_TYPE_PLAIN:
if (ofs_rem >= logical_cluster_ofs)
map->m_flags ^= EROFS_MAP_ZIPPED;
/* fallthrough */
case Z_EROFS_VLE_CLUSTER_TYPE_HEAD:
if (ofs_rem == logical_cluster_ofs) {
pblk = le32_to_cpu(di->di_u.blkaddr);
goto exact_hitted;
}
if (ofs_rem > logical_cluster_ofs) {
ofs = (u64)lcn * clustersize | logical_cluster_ofs;
pblk = le32_to_cpu(di->di_u.blkaddr);
break;
}
/* logical cluster number should be >= 1 */
if (unlikely(!lcn)) {
errln("invalid logical cluster 0 at nid %llu",
EROFS_V(inode)->nid);
err = -EIO;
goto unmap_out;
}
end = ((u64)lcn-- * clustersize) | logical_cluster_ofs;
/* fallthrough */
case Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD:
/* get the correspoinding first chunk */
err = vle_get_logical_extent_head(&ctx, lcn, &ofs,
&pblk, &map->m_flags);
mpage = map->mpage;
if (unlikely(err)) {
if (mpage)
goto unmap_out;
goto out;
}
break;
default:
errln("unknown cluster type %u at offset %llu of nid %llu",
cluster_type, ofs, EROFS_V(inode)->nid);
err = -EIO;
goto unmap_out;
}
map->m_la = ofs;
exact_hitted:
map->m_llen = end - ofs;
map->m_plen = clustersize;
map->m_pa = blknr_to_addr(pblk);
map->m_flags |= EROFS_MAP_MAPPED;
unmap_out:
kunmap_atomic(kaddr);
unlock_page(mpage);
out:
debugln("%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;
}

462
drivers/staging/erofs/zmap.c Normal file
View File

@ -0,0 +1,462 @@
// SPDX-License-Identifier: GPL-2.0
/*
* linux/drivers/staging/erofs/zmap.c
*
* Copyright (C) 2018-2019 HUAWEI, Inc.
* http://www.huawei.com/
* Created by Gao Xiang <gaoxiang25@huawei.com>
*/
#include "internal.h"
#include <asm/unaligned.h>
#include <trace/events/erofs.h>
int z_erofs_fill_inode(struct inode *inode)
{
struct erofs_vnode *const vi = EROFS_V(inode);
struct super_block *const sb = inode->i_sb;
if (vi->datamode == EROFS_INODE_FLAT_COMPRESSION_LEGACY) {
vi->z_advise = 0;
vi->z_algorithmtype[0] = 0;
vi->z_algorithmtype[1] = 0;
vi->z_logical_clusterbits = EROFS_SB(sb)->clusterbits;
vi->z_physical_clusterbits[0] = vi->z_logical_clusterbits;
vi->z_physical_clusterbits[1] = vi->z_logical_clusterbits;
set_bit(EROFS_V_Z_INITED_BIT, &vi->flags);
}
inode->i_mapping->a_ops = &z_erofs_vle_normalaccess_aops;
return 0;
}
static int fill_inode_lazy(struct inode *inode)
{
struct erofs_vnode *const vi = EROFS_V(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_V_Z_INITED_BIT, &vi->flags))
return 0;
if (wait_on_bit_lock(&vi->flags, EROFS_V_BL_Z_BIT, TASK_KILLABLE))
return -ERESTARTSYS;
err = 0;
if (test_bit(EROFS_V_Z_INITED_BIT, &vi->flags))
goto out_unlock;
DBG_BUGON(vi->datamode == 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), false);
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) {
errln("unknown compression format %u for nid %llu, please upgrade kernel",
vi->z_algorithmtype[0], vi->nid);
err = -ENOTSUPP;
goto unmap_done;
}
vi->z_logical_clusterbits = LOG_BLOCK_SIZE + (h->h_clusterbits & 7);
vi->z_physical_clusterbits[0] = vi->z_logical_clusterbits +
((h->h_clusterbits >> 3) & 3);
if (vi->z_physical_clusterbits[0] != LOG_BLOCK_SIZE) {
errln("unsupported physical clusterbits %u for nid %llu, please upgrade kernel",
vi->z_physical_clusterbits[0], vi->nid);
err = -ENOTSUPP;
goto unmap_done;
}
vi->z_physical_clusterbits[1] = vi->z_logical_clusterbits +
((h->h_clusterbits >> 5) & 7);
unmap_done:
kunmap_atomic(kaddr);
unlock_page(page);
put_page(page);
set_bit(EROFS_V_Z_INITED_BIT, &vi->flags);
out_unlock:
clear_and_wake_up_bit(EROFS_V_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;
};
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, false);
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 vle_legacy_load_cluster_from_disk(struct z_erofs_maprecorder *m,
unsigned long lcn)
{
struct inode *const inode = m->inode;
struct erofs_vnode *const vi = EROFS_V(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]);
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 -EIO;
}
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 unpack_compacted_index(struct z_erofs_maprecorder *m,
unsigned int amortizedshift,
unsigned int eofs)
{
struct erofs_vnode *const vi = EROFS_V(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;
if (1 << amortizedshift == 4)
vcnt = 2;
else if (1 << amortizedshift == 2 && lclusterbits == 12)
vcnt = 16;
else
return -ENOTSUPP;
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;
if (i + 1 != 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;
m->delta[0] = lo + 1;
return 0;
}
m->clusterofs = lo;
m->delta[0] = 0;
/* figout out blkaddr (pblk) for HEAD lclusters */
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;
}
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)
{
struct inode *const inode = m->inode;
struct erofs_vnode *const vi = EROFS_V(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 -ENOTSUPP;
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_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));
}
static int vle_load_cluster_from_disk(struct z_erofs_maprecorder *m,
unsigned int lcn)
{
const unsigned int datamode = EROFS_V(m->inode)->datamode;
if (datamode == EROFS_INODE_FLAT_COMPRESSION_LEGACY)
return vle_legacy_load_cluster_from_disk(m, lcn);
if (datamode == EROFS_INODE_FLAT_COMPRESSION)
return compacted_load_cluster_from_disk(m, lcn);
return -EINVAL;
}
static int vle_extent_lookback(struct z_erofs_maprecorder *m,
unsigned int lookback_distance)
{
struct erofs_vnode *const vi = EROFS_V(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) {
DBG_BUGON(1);
return -EIO;
}
/* load extent head logical cluster if needed */
lcn -= lookback_distance;
err = vle_load_cluster_from_disk(m, lcn);
if (err)
return err;
switch (m->type) {
case Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD:
return vle_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:
errln("unknown type %u at lcn %lu of nid %llu",
m->type, lcn, vi->nid);
DBG_BUGON(1);
return -EIO;
}
return 0;
}
int z_erofs_map_blocks_iter(struct inode *inode,
struct erofs_map_blocks *map,
int flags)
{
struct erofs_vnode *const vi = EROFS_V(inode);
struct z_erofs_maprecorder m = {
.inode = inode,
.map = map,
};
int err = 0;
unsigned int lclusterbits, endoff;
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 (unlikely(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 = fill_inode_lazy(inode);
if (err)
goto out;
lclusterbits = vi->z_logical_clusterbits;
ofs = map->m_la;
m.lcn = ofs >> lclusterbits;
endoff = ofs & ((1 << lclusterbits) - 1);
err = vle_load_cluster_from_disk(&m, m.lcn);
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 (unlikely(!m.lcn)) {
errln("invalid logical cluster 0 at nid %llu",
vi->nid);
err = -EIO;
goto unmap_out;
}
end = (m.lcn << lclusterbits) | m.clusterofs;
m.delta[0] = 1;
/* fallthrough */
case Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD:
/* get the correspoinding first chunk */
err = vle_extent_lookback(&m, m.delta[0]);
if (unlikely(err))
goto unmap_out;
break;
default:
errln("unknown type %u at offset %llu of nid %llu",
m.type, ofs, vi->nid);
err = -EIO;
goto unmap_out;
}
map->m_llen = end - map->m_la;
map->m_plen = 1 << lclusterbits;
map->m_pa = blknr_to_addr(m.pblk);
map->m_flags |= EROFS_MAP_MAPPED;
unmap_out:
if (m.kaddr)
kunmap_atomic(m.kaddr);
out:
debugln("%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;
}