On 05/05, Chao Yu wrote: > On 2020-5-4 22:30, Jaegeuk Kim wrote: > > From: Daeho Jeong <daehoje...@google.com> > > > > Current zstd compression buffer size is one page and header size less > > than cluster size. By this, zstd compression always succeeds even if > > the real compression data is failed to fit into the buffer size, and > > eventually reading the cluster returns I/O error with the corrupted > > compression data. > > What's the root cause of this issue? I didn't get it. > > > > > Signed-off-by: Daeho Jeong <daehoje...@google.com> > > --- > > fs/f2fs/compress.c | 4 ++-- > > 1 file changed, 2 insertions(+), 2 deletions(-) > > > > diff --git a/fs/f2fs/compress.c b/fs/f2fs/compress.c > > index 4c7eaeee52336..a9fa8049b295f 100644 > > --- a/fs/f2fs/compress.c > > +++ b/fs/f2fs/compress.c > > @@ -313,7 +313,7 @@ static int zstd_init_compress_ctx(struct compress_ctx > > *cc) > > cc->private = workspace; > > cc->private2 = stream; > > > > - cc->clen = cc->rlen - PAGE_SIZE - COMPRESS_HEADER_SIZE; > > + cc->clen = ZSTD_compressBound(PAGE_SIZE << cc->log_cluster_size); > > In my machine, the value is 66572 which is much larger than size of dst > buffer, so, in where we can tell the real size of dst buffer to zstd > compressor? Otherwise, if compressed data size is larger than dst buffer > size, when we flush compressed data into dst buffer, we may suffer overflow.
Could you give it a try compress_log_size=2 and check decompression works? > > > return 0; > > } > > > > @@ -330,7 +330,7 @@ static int zstd_compress_pages(struct compress_ctx *cc) > > ZSTD_inBuffer inbuf; > > ZSTD_outBuffer outbuf; > > int src_size = cc->rlen; > > - int dst_size = src_size - PAGE_SIZE - COMPRESS_HEADER_SIZE; > > + int dst_size = cc->clen; > > int ret; > > > > inbuf.pos = 0; > >
