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Subject[PATCH v3 2/8] staging: erofs: add compacted compression indexes support
Date
From: Gao Xiang <gaoxiang25@huawei.com>

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>
---
change log v3:
- wrap up offset for better readability pointed out by Chao.

drivers/staging/erofs/Makefile | 2 +-
drivers/staging/erofs/inode.c | 7 +-
drivers/staging/erofs/internal.h | 18 +-
drivers/staging/erofs/unzip_vle.c | 286 ------------------
drivers/staging/erofs/zmap.c | 462 ++++++++++++++++++++++++++++++
5 files changed, 480 insertions(+), 295 deletions(-)
create mode 100644 drivers/staging/erofs/zmap.c

diff --git a/drivers/staging/erofs/Makefile b/drivers/staging/erofs/Makefile
index a34248a2a16a..84b412c7a991 100644
--- a/drivers/staging/erofs/Makefile
+++ b/drivers/staging/erofs/Makefile
@@ -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

diff --git a/drivers/staging/erofs/inode.c b/drivers/staging/erofs/inode.c
index 3539290b8e45..1d467322bacf 100644
--- a/drivers/staging/erofs/inode.c
+++ b/drivers/staging/erofs/inode.c
@@ -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;
}

diff --git a/drivers/staging/erofs/internal.h b/drivers/staging/erofs/internal.h
index c851d0be6cf6..f3063b13c117 100644
--- a/drivers/staging/erofs/internal.h
+++ b/drivers/staging/erofs/internal.h
@@ -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)
diff --git a/drivers/staging/erofs/unzip_vle.c b/drivers/staging/erofs/unzip_vle.c
index ae62293d5a82..8aea938172df 100644
--- a/drivers/staging/erofs/unzip_vle.c
+++ b/drivers/staging/erofs/unzip_vle.c
@@ -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;
-}
-
diff --git a/drivers/staging/erofs/zmap.c b/drivers/staging/erofs/zmap.c
new file mode 100644
index 000000000000..1e75cef11db4
--- /dev/null
+++ b/drivers/staging/erofs/zmap.c
@@ -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;
+}
+
--
2.17.1
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