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[Qemu-devel] [PATCH 4/5] qemu-file: Fix qemu_put_compression_data flaw
From: |
Liang Li |
Subject: |
[Qemu-devel] [PATCH 4/5] qemu-file: Fix qemu_put_compression_data flaw |
Date: |
Wed, 4 May 2016 11:40:58 +0800 |
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.
Suggested-by: Juan Quintela <address@hidden>
Signed-off-by: Liang Li <address@hidden>
---
migration/qemu-file.c | 23 +++++++++++++++++++++--
migration/ram.c | 6 +++++-
2 files changed, 26 insertions(+), 3 deletions(-)
diff --git a/migration/qemu-file.c b/migration/qemu-file.c
index 6f4a129..b0ef1f3 100644
--- a/migration/qemu-file.c
+++ b/migration/qemu-file.c
@@ -607,8 +607,14 @@ 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,
@@ -617,7 +623,14 @@ 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) {
@@ -625,7 +638,13 @@ 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 bc34bc5..7e62d8d 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -821,7 +821,11 @@ 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) {
+ error_report("Insufficient buffer for compressed data!");
+ } else {
+ bytes_sent += blen;
+ }
return bytes_sent;
}
--
1.9.1
- [Qemu-devel] [PATCH 1/5] migration: Fix multi-thread compression bug, (continued)