On 2020/5/6 7:05, Jaegeuk Kim wrote: > 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?
I tried some samples before submitting the patch, did you encounter app's data corruption when using zstd algorithm? If so, let me check this issue. Thanks, > >> >>> 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; >>> > > > _______________________________________________ > Linux-f2fs-devel mailing list > linux-f2fs-de...@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel > . >
