[PATCH v2 3/3] fs/erofs: add lz4 decompression support
Huang Jianan
jnhuang95 at gmail.com
Mon Aug 23 14:36:46 CEST 2021
From: Huang Jianan <huangjianan at oppo.com>
Support EROFS lz4 compressed files.
Signed-off-by: Huang Jianan <huangjianan at oppo.com>
---
fs/erofs/Makefile | 4 +-
fs/erofs/data.c | 84 ++++++-
fs/erofs/decompress.c | 74 ++++++
fs/erofs/decompress.h | 29 +++
fs/erofs/namei.c | 2 +-
fs/erofs/zmap.c | 517 ++++++++++++++++++++++++++++++++++++++++++
6 files changed, 707 insertions(+), 3 deletions(-)
create mode 100644 fs/erofs/decompress.c
create mode 100644 fs/erofs/decompress.h
create mode 100644 fs/erofs/zmap.c
diff --git a/fs/erofs/Makefile b/fs/erofs/Makefile
index c4fc5b794e..8f1f99a096 100644
--- a/fs/erofs/Makefile
+++ b/fs/erofs/Makefile
@@ -5,4 +5,6 @@ obj-$(CONFIG_$(SPL_)FS_EROFS) = fs.o \
super.o \
namei.o \
data.o \
- lz4.o
+ lz4.o \
+ decompress.o \
+ zmap.o
diff --git a/fs/erofs/data.c b/fs/erofs/data.c
index a0f613264a..04ba9b5765 100644
--- a/fs/erofs/data.c
+++ b/fs/erofs/data.c
@@ -1,5 +1,6 @@
// SPDX-License-Identifier: GPL-2.0+
#include "internal.h"
+#include "decompress.h"
static int erofs_map_blocks_flatmode(struct erofs_inode *inode,
struct erofs_map_blocks *map,
@@ -107,6 +108,87 @@ static int erofs_read_raw_data(struct erofs_inode *inode, char *buffer,
return 0;
}
+static int z_erofs_read_data(struct erofs_inode *inode, char *buffer,
+ erofs_off_t size, erofs_off_t offset)
+{
+ erofs_off_t end, length, skip;
+ struct erofs_map_blocks map = {
+ .index = UINT_MAX,
+ };
+ bool partial;
+ unsigned int algorithmformat, bufsize;
+ char *raw = NULL;
+ int ret = 0;
+
+ end = offset + size;
+ bufsize = 0;
+ while (end > offset) {
+ map.m_la = end - 1;
+
+ ret = z_erofs_map_blocks_iter(inode, &map);
+ if (ret)
+ break;
+
+ /*
+ * trim to the needed size if the returned extent is quite
+ * larger than requested, and set up partial flag as well.
+ */
+ if (end < map.m_la + map.m_llen) {
+ length = end - map.m_la;
+ partial = true;
+ } else {
+ DBG_BUGON(end != map.m_la + map.m_llen);
+ length = map.m_llen;
+ partial = !(map.m_flags & EROFS_MAP_FULL_MAPPED);
+ }
+
+ if (map.m_la < offset) {
+ skip = offset - map.m_la;
+ end = offset;
+ } else {
+ skip = 0;
+ end = map.m_la;
+ }
+
+ if (!(map.m_flags & EROFS_MAP_MAPPED)) {
+ memset(buffer + end - offset, 0, length);
+ end = map.m_la;
+ continue;
+ }
+
+ if (map.m_plen > bufsize) {
+ bufsize = map.m_plen;
+ raw = realloc(raw, bufsize);
+ if (!raw) {
+ ret = -ENOMEM;
+ break;
+ }
+ }
+ ret = erofs_dev_read(raw, map.m_pa, map.m_plen);
+ if (ret < 0)
+ break;
+
+ algorithmformat = map.m_flags & EROFS_MAP_ZIPPED ?
+ Z_EROFS_COMPRESSION_LZ4 :
+ Z_EROFS_COMPRESSION_SHIFTED;
+
+ ret = z_erofs_decompress(&(struct z_erofs_decompress_req) {
+ .in = raw,
+ .out = buffer + end - offset,
+ .decodedskip = skip,
+ .inputsize = map.m_plen,
+ .decodedlength = length,
+ .alg = algorithmformat,
+ .partial_decoding = partial
+ });
+ if (ret < 0)
+ break;
+ }
+ if (raw)
+ free(raw);
+ return ret < 0 ? ret : 0;
+}
+
int erofs_pread(struct erofs_inode *inode, char *buf,
erofs_off_t count, erofs_off_t offset)
{
@@ -116,7 +198,7 @@ int erofs_pread(struct erofs_inode *inode, char *buf,
return erofs_read_raw_data(inode, buf, count, offset);
case EROFS_INODE_FLAT_COMPRESSION_LEGACY:
case EROFS_INODE_FLAT_COMPRESSION:
- return -EOPNOTSUPP;
+ return z_erofs_read_data(inode, buf, count, offset);
default:
break;
}
diff --git a/fs/erofs/decompress.c b/fs/erofs/decompress.c
new file mode 100644
index 0000000000..f960f6442a
--- /dev/null
+++ b/fs/erofs/decompress.c
@@ -0,0 +1,74 @@
+// SPDX-License-Identifier: GPL-2.0+
+#include "decompress.h"
+#include "lz4.h"
+
+static int z_erofs_decompress_lz4(struct z_erofs_decompress_req *rq)
+{
+ int ret = 0;
+ char *dest = rq->out;
+ char *src = rq->in;
+ char *buff = NULL;
+ bool support_0padding = false;
+ unsigned int inputmargin = 0;
+
+ if (erofs_sb_has_lz4_0padding()) {
+ support_0padding = true;
+
+ while (!src[inputmargin & ~PAGE_MASK])
+ if (!(++inputmargin & ~PAGE_MASK))
+ break;
+
+ if (inputmargin >= rq->inputsize)
+ return -EIO;
+ }
+
+ if (rq->decodedskip) {
+ buff = malloc(rq->decodedlength);
+ if (!buff)
+ return -ENOMEM;
+ dest = buff;
+ }
+
+ if (rq->partial_decoding || !support_0padding)
+ ret = LZ4_decompress_safe_partial(src + inputmargin, dest,
+ rq->inputsize - inputmargin,
+ rq->decodedlength, rq->decodedlength);
+ else
+ ret = LZ4_decompress_safe(src + inputmargin, dest,
+ rq->inputsize - inputmargin,
+ rq->decodedlength);
+
+ if (ret != (int)rq->decodedlength) {
+ ret = -EIO;
+ goto out;
+ }
+
+ if (rq->decodedskip)
+ memcpy(rq->out, dest + rq->decodedskip,
+ rq->decodedlength - rq->decodedskip);
+
+out:
+ if (buff)
+ free(buff);
+
+ return ret;
+}
+
+int z_erofs_decompress(struct z_erofs_decompress_req *rq)
+{
+ if (rq->alg == Z_EROFS_COMPRESSION_SHIFTED) {
+ if (rq->inputsize != EROFS_BLKSIZ)
+ return -EFSCORRUPTED;
+
+ DBG_BUGON(rq->decodedlength > EROFS_BLKSIZ);
+ DBG_BUGON(rq->decodedlength < rq->decodedskip);
+
+ memcpy(rq->out, rq->in + rq->decodedskip,
+ rq->decodedlength - rq->decodedskip);
+ return 0;
+ }
+
+ if (rq->alg == Z_EROFS_COMPRESSION_LZ4)
+ return z_erofs_decompress_lz4(rq);
+ return -EOPNOTSUPP;
+}
diff --git a/fs/erofs/decompress.h b/fs/erofs/decompress.h
new file mode 100644
index 0000000000..a12e11f386
--- /dev/null
+++ b/fs/erofs/decompress.h
@@ -0,0 +1,29 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+#ifndef __EROFS_DECOMPRESS_H
+#define __EROFS_DECOMPRESS_H
+
+#include "internal.h"
+
+enum {
+ Z_EROFS_COMPRESSION_SHIFTED = Z_EROFS_COMPRESSION_MAX,
+ Z_EROFS_COMPRESSION_RUNTIME_MAX
+};
+
+struct z_erofs_decompress_req {
+ char *in, *out;
+
+ /*
+ * initial decompressed bytes that need to be skipped
+ * when finally copying to output buffer
+ */
+ unsigned int decodedskip;
+ unsigned int inputsize, decodedlength;
+
+ /* indicate the algorithm will be used for decompression */
+ unsigned int alg;
+ bool partial_decoding;
+};
+
+int z_erofs_decompress(struct z_erofs_decompress_req *rq);
+
+#endif
diff --git a/fs/erofs/namei.c b/fs/erofs/namei.c
index 4c5d614483..7a0fbe2bc1 100644
--- a/fs/erofs/namei.c
+++ b/fs/erofs/namei.c
@@ -101,7 +101,7 @@ int erofs_read_inode_from_disk(struct erofs_inode *vi)
vi->flags = 0;
if (erofs_inode_is_data_compressed(vi->datalayout))
- return -EOPNOTSUPP;
+ z_erofs_fill_inode(vi);
return 0;
bogusimode:
erofs_err("bogus i_mode (%o) @ nid %llu", vi->i_mode, vi->nid | 0ULL);
diff --git a/fs/erofs/zmap.c b/fs/erofs/zmap.c
new file mode 100644
index 0000000000..ff7f89f40c
--- /dev/null
+++ b/fs/erofs/zmap.c
@@ -0,0 +1,517 @@
+// SPDX-License-Identifier: GPL-2.0+
+#include "internal.h"
+
+int z_erofs_fill_inode(struct erofs_inode *vi)
+{
+ if (!erofs_sb_has_big_pcluster() &&
+ 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;
+
+ vi->flags |= EROFS_I_Z_INITED;
+ }
+ return 0;
+}
+
+static int z_erofs_fill_inode_lazy(struct erofs_inode *vi)
+{
+ int ret;
+ erofs_off_t pos;
+ struct z_erofs_map_header *h;
+ char buf[sizeof(struct z_erofs_map_header)];
+
+ if (vi->flags & EROFS_I_Z_INITED)
+ return 0;
+
+ DBG_BUGON(!erofs_sb_has_big_pcluster() &&
+ vi->datalayout == EROFS_INODE_FLAT_COMPRESSION_LEGACY);
+ pos = round_up(iloc(vi->nid) + vi->inode_isize + vi->xattr_isize, 8);
+
+ ret = erofs_dev_read(buf, pos, sizeof(buf));
+ if (ret < 0)
+ return -EIO;
+
+ h = (struct z_erofs_map_header *)buf;
+ 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("unknown compression format %u for nid %llu",
+ vi->z_algorithmtype[0], (unsigned long long)vi->nid);
+ return -EOPNOTSUPP;
+ }
+
+ vi->z_logical_clusterbits = LOG_BLOCK_SIZE + (h->h_clusterbits & 7);
+ 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(
+"big pcluster head1/2 of compact indexes should be consistent for nid %llu",
+ vi->nid * 1ULL);
+ return -EFSCORRUPTED;
+ }
+ vi->flags |= EROFS_I_Z_INITED;
+ return 0;
+}
+
+struct z_erofs_maprecorder {
+ struct erofs_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)
+{
+ int ret;
+ struct erofs_map_blocks *const map = m->map;
+ char *mpage = map->mpage;
+
+ if (map->index == eblk)
+ return 0;
+
+ ret = erofs_blk_read(mpage, eblk, 1);
+ if (ret < 0)
+ return -EIO;
+
+ map->index = eblk;
+
+ return 0;
+}
+
+static int legacy_load_cluster_from_disk(struct z_erofs_maprecorder *m,
+ unsigned long lcn)
+{
+ struct erofs_inode *const vi = m->inode;
+ const erofs_off_t ibase = iloc(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 unpack_compacted_index(struct z_erofs_maprecorder *m,
+ unsigned int amortizedshift,
+ unsigned int eofs)
+{
+ struct erofs_inode *const vi = 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;
+ 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;
+ }
+ if (lo == 1) {
+ DBG_BUGON(1);
+ /* --i; ++nblk; continue; */
+ 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)
+{
+ struct erofs_inode *const vi = m->inode;
+ const unsigned int lclusterbits = vi->z_logical_clusterbits;
+ const erofs_off_t ebase = round_up(iloc(vi->nid) + vi->inode_isize +
+ vi->xattr_isize, 8) +
+ sizeof(struct z_erofs_map_header);
+ const unsigned int totalidx = DIV_ROUND_UP(vi->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_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 z_erofs_load_cluster_from_disk(struct z_erofs_maprecorder *m,
+ unsigned int lcn)
+{
+ const unsigned int datamode = 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);
+
+ return -EINVAL;
+}
+
+static int z_erofs_extent_lookback(struct z_erofs_maprecorder *m,
+ unsigned int lookback_distance)
+{
+ struct erofs_inode *const vi = 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("bogus lookback distance @ nid %llu",
+ (unsigned long long)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);
+ if (err)
+ return err;
+
+ switch (m->type) {
+ case Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD:
+ if (!m->delta[0]) {
+ erofs_err("invalid lookback distance 0 @ nid %llu",
+ (unsigned long long)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;
+ case Z_EROFS_VLE_CLUSTER_TYPE_HEAD:
+ map->m_la = (lcn << lclusterbits) | m->clusterofs;
+ break;
+ default:
+ erofs_err("unknown type %u @ lcn %lu of nid %llu",
+ m->type, lcn, (unsigned long long)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 = 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);
+ 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("cannot found CBLKCNT @ lcn %lu of nid %llu",
+ lcn, vi->nid | 0ULL);
+ DBG_BUGON(1);
+ return -EFSCORRUPTED;
+ }
+out:
+ map->m_plen = m->compressedlcs << lclusterbits;
+ return 0;
+err_bonus_cblkcnt:
+ erofs_err("bogus CBLKCNT @ lcn %lu of nid %llu",
+ lcn, vi->nid | 0ULL);
+ DBG_BUGON(1);
+ return -EFSCORRUPTED;
+}
+
+int z_erofs_map_blocks_iter(struct erofs_inode *vi,
+ struct erofs_map_blocks *map)
+{
+ struct z_erofs_maprecorder m = {
+ .inode = vi,
+ .map = map,
+ .kaddr = map->mpage,
+ };
+ int err = 0;
+ unsigned int lclusterbits, endoff;
+ unsigned long initial_lcn;
+ unsigned long long ofs, end;
+
+ /* when trying to read beyond EOF, leave it unmapped */
+ if (map->m_la >= vi->i_size) {
+ map->m_llen = map->m_la + 1 - vi->i_size;
+ map->m_la = vi->i_size;
+ map->m_flags = 0;
+ goto out;
+ }
+
+ err = z_erofs_fill_inode_lazy(vi);
+ 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);
+ if (err)
+ goto 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;
+ 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("invalid logical cluster 0 at nid %llu",
+ (unsigned long long)vi->nid);
+ err = -EFSCORRUPTED;
+ goto out;
+ }
+ end = (m.lcn << lclusterbits) | m.clusterofs;
+ map->m_flags |= EROFS_MAP_FULL_MAPPED;
+ m.delta[0] = 1;
+ case Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD:
+ /* get the correspoinding first chunk */
+ err = z_erofs_extent_lookback(&m, m.delta[0]);
+ if (err)
+ goto out;
+ break;
+ default:
+ erofs_err("unknown type %u @ offset %llu of nid %llu",
+ m.type, ofs, (unsigned long long)vi->nid);
+ err = -EOPNOTSUPP;
+ goto 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;
+ map->m_flags |= EROFS_MAP_MAPPED;
+
+out:
+ erofs_dbg("m_la %" PRIu64 " m_pa %" PRIu64 " m_llen %" PRIu64 " m_plen %" PRIu64 " m_flags 0%o",
+ map->m_la, map->m_pa,
+ map->m_llen, map->m_plen, map->m_flags);
+
+ DBG_BUGON(err < 0 && err != -ENOMEM);
+ return err;
+}
--
2.25.1
More information about the U-Boot
mailing list