From b3be28969b797b27d7f7f806827e9898e4ee08f0 Mon Sep 17 00:00:00 2001 From: Liang Li Date: Thu, 5 May 2016 15:32:54 +0800 Subject: [PATCH] qemu-file: Fix qemu_put_compression_data flaw Current qemu_put_compression_data can only work with no writable QEMUFile, and can't work with the writable QEMUFile. But it does not provide any measure to prevent users from using it with a writable QEMUFile. We should fix this flaw to make it works with writable QEMUFile. Signed-off-by: Liang Li Suggested-by: Juan Quintela Message-Id: <1462433579-13691-5-git-send-email-liang.z.li@intel.com> Signed-off-by: Amit Shah --- migration/qemu-file.c | 23 +++++++++++++++++++++-- migration/ram.c | 18 +++++++++++++----- 2 files changed, 34 insertions(+), 7 deletions(-) diff --git a/migration/qemu-file.c b/migration/qemu-file.c index 8aea1c7094..bbc565eb53 100644 --- a/migration/qemu-file.c +++ b/migration/qemu-file.c @@ -615,8 +615,14 @@ uint64_t qemu_get_be64(QEMUFile *f) return v; } -/* compress size bytes of data start at p with specific compression +/* Compress size bytes of data start at p with specific compression * level and store the compressed data to the buffer of f. + * + * When f is not writable, return -1 if f has no space to save the + * compressed data. + * When f is wirtable and it has no space to save the compressed data, + * do fflush first, if f still has no space to save the compressed + * data, return -1. */ ssize_t qemu_put_compression_data(QEMUFile *f, const uint8_t *p, size_t size, @@ -625,7 +631,14 @@ ssize_t qemu_put_compression_data(QEMUFile *f, const uint8_t *p, size_t size, ssize_t blen = IO_BUF_SIZE - f->buf_index - sizeof(int32_t); if (blen < compressBound(size)) { - return 0; + if (!qemu_file_is_writable(f)) { + return -1; + } + qemu_fflush(f); + blen = IO_BUF_SIZE - sizeof(int32_t); + if (blen < compressBound(size)) { + return -1; + } } if (compress2(f->buf + f->buf_index + sizeof(int32_t), (uLongf *)&blen, (Bytef *)p, size, level) != Z_OK) { @@ -633,7 +646,13 @@ ssize_t qemu_put_compression_data(QEMUFile *f, const uint8_t *p, size_t size, return 0; } qemu_put_be32(f, blen); + if (f->ops->writev_buffer) { + add_to_iovec(f, f->buf + f->buf_index, blen); + } f->buf_index += blen; + if (f->buf_index == IO_BUF_SIZE) { + qemu_fflush(f); + } return blen + sizeof(int32_t); } diff --git a/migration/ram.c b/migration/ram.c index 6416e60412..d30c923195 100644 --- a/migration/ram.c +++ b/migration/ram.c @@ -821,7 +821,13 @@ static int do_compress_ram_page(CompressParam *param) RAM_SAVE_FLAG_COMPRESS_PAGE); blen = qemu_put_compression_data(param->file, p, TARGET_PAGE_SIZE, migrate_compress_level()); - bytes_sent += blen; + if (blen < 0) { + bytes_sent = 0; + qemu_file_set_error(migrate_get_current()->to_dst_file, blen); + error_report("compressed data failed!"); + } else { + bytes_sent += blen; + } return bytes_sent; } @@ -965,10 +971,12 @@ static int ram_save_compressed_page(QEMUFile *f, PageSearchStatus *pss, * first page is sent out before other pages */ bytes_xmit = do_compress_ram_page(&comp_param[0]); - acct_info.norm_pages++; - qemu_put_qemu_file(f, comp_param[0].file); - *bytes_transferred += bytes_xmit; - pages = 1; + if (bytes_xmit > 0) { + acct_info.norm_pages++; + qemu_put_qemu_file(f, comp_param[0].file); + *bytes_transferred += bytes_xmit; + pages = 1; + } } } else { pages = save_zero_page(f, block, offset, p, bytes_transferred);