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qemu-file: Fix qemu_put_compression_data flaw

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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 <liang.z.li@intel.com>
Suggested-by: Juan Quintela <quintela@redhat.com>
Message-Id: <1462433579-13691-5-git-send-email-liang.z.li@intel.com>
Signed-off-by: Amit Shah <amit.shah@redhat.com>
This commit is contained in:
Liang Li 2016-05-05 15:32:54 +08:00 committed by Amit Shah
parent e7bb92e21a
commit b3be28969b
2 changed files with 34 additions and 7 deletions
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23
migration/qemu-file.c
View file

@ -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);
}

18
migration/ram.c
View file

@ -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);