[PATCH v6 1/2] erofs: support interlaced uncompressed data for compressed files
Yue Hu
zbestahu at gmail.com
Fri Sep 23 12:11:21 AEST 2022
From: Yue Hu <huyue2 at coolpad.com>
Currently, uncompressed data is all handled in the shifted way, which
means we have to shift the whole on-disk plain pcluster to get the
logical data. However, since we are also using in-place I/O for
uncompressed data, data copy will be reduced a lot if pcluster is
recorded in the interlaced way as illustrated below:
_______________________________________________________________
| | | |_ tail part |_ head part _|
|<- blk0 ->| .. |<- blkn-2 ->|<- blkn-1 ->|
The logical data then becomes:
________________________________________________________
|_ head part _|_ blk0 _| .. |_ blkn-2 _|_ tail part _|
In addition, non-4k plain pclusters are also survived by the
interlaced way, which can be used for non-4k lclusters as well.
However, it's almost impossible to de-duplicate uncompressed data
in the interlaced way, therefore shifted uncompressed data is still
useful.
Signed-off-by: Yue Hu <huyue2 at coolpad.com>
Reviewed-by: Gao Xiang <hsiangkao at linux.alibaba.com>
---
fs/erofs/decompressor.c | 47 ++++++++++++++++++++++++-----------------
fs/erofs/erofs_fs.h | 2 ++
fs/erofs/internal.h | 1 +
fs/erofs/zmap.c | 14 ++++++++----
4 files changed, 41 insertions(+), 23 deletions(-)
diff --git a/fs/erofs/decompressor.c b/fs/erofs/decompressor.c
index 2d55569f96ac..51b7ac7166d9 100644
--- a/fs/erofs/decompressor.c
+++ b/fs/erofs/decompressor.c
@@ -317,52 +317,61 @@ static int z_erofs_lz4_decompress(struct z_erofs_decompress_req *rq,
return ret;
}
-static int z_erofs_shifted_transform(struct z_erofs_decompress_req *rq,
- struct page **pagepool)
+static int z_erofs_transform_plain(struct z_erofs_decompress_req *rq,
+ struct page **pagepool)
{
- const unsigned int nrpages_out =
+ const unsigned int inpages = PAGE_ALIGN(rq->inputsize) >> PAGE_SHIFT;
+ const unsigned int outpages =
PAGE_ALIGN(rq->pageofs_out + rq->outputsize) >> PAGE_SHIFT;
const unsigned int righthalf = min_t(unsigned int, rq->outputsize,
PAGE_SIZE - rq->pageofs_out);
const unsigned int lefthalf = rq->outputsize - righthalf;
+ const unsigned int interlaced_offset =
+ rq->alg == Z_EROFS_COMPRESSION_SHIFTED ? 0 : rq->pageofs_out;
unsigned char *src, *dst;
- if (nrpages_out > 2) {
+ if (outpages > 2 && rq->alg == Z_EROFS_COMPRESSION_SHIFTED) {
DBG_BUGON(1);
- return -EIO;
+ return -EFSCORRUPTED;
}
if (rq->out[0] == *rq->in) {
- DBG_BUGON(nrpages_out != 1);
+ DBG_BUGON(rq->pageofs_out);
return 0;
}
- src = kmap_atomic(*rq->in) + rq->pageofs_in;
+ src = kmap_local_page(rq->in[inpages - 1]) + rq->pageofs_in;
if (rq->out[0]) {
- dst = kmap_atomic(rq->out[0]);
- memcpy(dst + rq->pageofs_out, src, righthalf);
- kunmap_atomic(dst);
+ dst = kmap_local_page(rq->out[0]);
+ memcpy(dst + rq->pageofs_out, src + interlaced_offset,
+ righthalf);
+ kunmap_local(dst);
}
- if (nrpages_out == 2) {
- DBG_BUGON(!rq->out[1]);
- if (rq->out[1] == *rq->in) {
+ if (outpages > inpages) {
+ DBG_BUGON(!rq->out[outpages - 1]);
+ if (rq->out[outpages - 1] != rq->in[inpages - 1]) {
+ dst = kmap_local_page(rq->out[outpages - 1]);
+ memcpy(dst, interlaced_offset ? src :
+ (src + righthalf), lefthalf);
+ kunmap_local(dst);
+ } else if (!interlaced_offset) {
memmove(src, src + righthalf, lefthalf);
- } else {
- dst = kmap_atomic(rq->out[1]);
- memcpy(dst, src + righthalf, lefthalf);
- kunmap_atomic(dst);
}
}
- kunmap_atomic(src);
+ kunmap_local(src);
return 0;
}
static struct z_erofs_decompressor decompressors[] = {
[Z_EROFS_COMPRESSION_SHIFTED] = {
- .decompress = z_erofs_shifted_transform,
+ .decompress = z_erofs_transform_plain,
.name = "shifted"
},
+ [Z_EROFS_COMPRESSION_INTERLACED] = {
+ .decompress = z_erofs_transform_plain,
+ .name = "interlaced"
+ },
[Z_EROFS_COMPRESSION_LZ4] = {
.decompress = z_erofs_lz4_decompress,
.name = "lz4"
diff --git a/fs/erofs/erofs_fs.h b/fs/erofs/erofs_fs.h
index 2b48373f690b..5c1de6d7ad71 100644
--- a/fs/erofs/erofs_fs.h
+++ b/fs/erofs/erofs_fs.h
@@ -295,11 +295,13 @@ struct z_erofs_lzma_cfgs {
* bit 1 : HEAD1 big pcluster (0 - off; 1 - on)
* bit 2 : HEAD2 big pcluster (0 - off; 1 - on)
* bit 3 : tailpacking inline pcluster (0 - off; 1 - on)
+ * bit 4 : interlaced plain pcluster (0 - off; 1 - on)
*/
#define Z_EROFS_ADVISE_COMPACTED_2B 0x0001
#define Z_EROFS_ADVISE_BIG_PCLUSTER_1 0x0002
#define Z_EROFS_ADVISE_BIG_PCLUSTER_2 0x0004
#define Z_EROFS_ADVISE_INLINE_PCLUSTER 0x0008
+#define Z_EROFS_ADVISE_INTERLACED_PCLUSTER 0x0010
struct z_erofs_map_header {
__le16 h_reserved1;
diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
index cfee49d33b95..f3ed36445d73 100644
--- a/fs/erofs/internal.h
+++ b/fs/erofs/internal.h
@@ -436,6 +436,7 @@ struct erofs_map_blocks {
enum {
Z_EROFS_COMPRESSION_SHIFTED = Z_EROFS_COMPRESSION_MAX,
+ Z_EROFS_COMPRESSION_INTERLACED,
Z_EROFS_COMPRESSION_RUNTIME_MAX
};
diff --git a/fs/erofs/zmap.c b/fs/erofs/zmap.c
index d58549ca1df9..7196235a441c 100644
--- a/fs/erofs/zmap.c
+++ b/fs/erofs/zmap.c
@@ -679,12 +679,18 @@ static int z_erofs_do_map_blocks(struct inode *inode,
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)
+ if (m.headtype == Z_EROFS_VLE_CLUSTER_TYPE_PLAIN) {
+ if (vi->z_advise & Z_EROFS_ADVISE_INTERLACED_PCLUSTER)
+ map->m_algorithmformat =
+ Z_EROFS_COMPRESSION_INTERLACED;
+ else
+ 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
+ } else {
map->m_algorithmformat = vi->z_algorithmtype[0];
+ }
if ((flags & EROFS_GET_BLOCKS_FIEMAP) ||
((flags & EROFS_GET_BLOCKS_READMORE) &&
--
2.17.1
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