On Tue, Sep 13, 2022 at 07:05:51PM +0800, Yue Hu wrote: > From: Yue Hu <[email protected]> > > 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 <[email protected]>
This version looks good to me, Reviewed-by: Gao Xiang <[email protected]> Thanks, Gao Xiang > 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
