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[Qemu-block] [PATCH 17/18] qemu-io: Add background write
From: |
Max Reitz |
Subject: |
[Qemu-block] [PATCH 17/18] qemu-io: Add background write |
Date: |
Wed, 13 Sep 2017 20:19:09 +0200 |
Add a new parameter -B to qemu-io's write command. When used, qemu-io
will not wait for the result of the operation and instead execute it in
the background.
Signed-off-by: Max Reitz <address@hidden>
---
qemu-io-cmds.c | 83 +++++++++++++++++++++++++++++++++++++++++++++++++++++-----
1 file changed, 77 insertions(+), 6 deletions(-)
diff --git a/qemu-io-cmds.c b/qemu-io-cmds.c
index 2811a89099..c635a248f5 100644
--- a/qemu-io-cmds.c
+++ b/qemu-io-cmds.c
@@ -481,6 +481,62 @@ static int do_pwrite(BlockBackend *blk, char *buf, int64_t
offset,
typedef struct {
BlockBackend *blk;
int64_t offset;
+ int bytes;
+ char *buf;
+ int flags;
+} CoBackgroundWrite;
+
+static void coroutine_fn co_background_pwrite_entry(void *opaque)
+{
+ CoBackgroundWrite *data = opaque;
+ QEMUIOVector qiov;
+ int ret;
+
+ qemu_iovec_init(&qiov, 1);
+ qemu_iovec_add(&qiov, data->buf, data->bytes);
+
+ ret = blk_co_pwritev(data->blk, data->offset, data->bytes, &qiov,
+ data->flags);
+
+ qemu_iovec_destroy(&qiov);
+ g_free(data->buf);
+
+ if (ret < 0) {
+ Error *err;
+ error_setg_errno(&err, -ret, "Background write failed");
+ error_report_err(err);
+ }
+}
+
+/* Takes ownership of @buf */
+static int do_background_pwrite(BlockBackend *blk, char *buf, int64_t offset,
+ int64_t bytes, int flags)
+{
+ Coroutine *co;
+ CoBackgroundWrite *data;
+
+ if (bytes > INT_MAX) {
+ return -ERANGE;
+ }
+
+ data = g_new(CoBackgroundWrite, 1);
+ *data = (CoBackgroundWrite){
+ .blk = blk,
+ .offset = offset,
+ .bytes = bytes,
+ .buf = buf,
+ .flags = flags,
+ };
+
+ co = qemu_coroutine_create(co_background_pwrite_entry, data);
+ bdrv_coroutine_enter(blk_bs(blk), co);
+
+ return bytes;
+}
+
+typedef struct {
+ BlockBackend *blk;
+ int64_t offset;
int64_t bytes;
int64_t *total;
int flags;
@@ -931,6 +987,7 @@ static void write_help(void)
" Writes into a segment of the currently open file, using a buffer\n"
" filled with a set pattern (0xcdcdcdcd).\n"
" -b, -- write to the VM state rather than the virtual disk\n"
+" -B, -- just start a background write, do not wait for the result\n"
" -c, -- write compressed data with blk_write_compressed\n"
" -f, -- use Force Unit Access semantics\n"
" -p, -- ignored for backwards compatibility\n"
@@ -951,7 +1008,7 @@ static const cmdinfo_t write_cmd = {
.perm = BLK_PERM_WRITE,
.argmin = 2,
.argmax = -1,
- .args = "[-bcCfquz] [-P pattern] off len",
+ .args = "[-bBcCfquz] [-P pattern] off len",
.oneline = "writes a number of bytes at a specified offset",
.help = write_help,
};
@@ -961,6 +1018,7 @@ static int write_f(BlockBackend *blk, int argc, char
**argv)
struct timeval t1, t2;
bool Cflag = false, qflag = false, bflag = false;
bool Pflag = false, zflag = false, cflag = false;
+ bool background = false;
int flags = 0;
int c, cnt;
char *buf = NULL;
@@ -970,11 +1028,14 @@ static int write_f(BlockBackend *blk, int argc, char
**argv)
int64_t total = 0;
int pattern = 0xcd;
- while ((c = getopt(argc, argv, "bcCfpP:quz")) != -1) {
+ while ((c = getopt(argc, argv, "bBcCfpP:quz")) != -1) {
switch (c) {
case 'b':
bflag = true;
break;
+ case 'B':
+ background = true;
+ break;
case 'c':
cflag = true;
break;
@@ -1032,6 +1093,11 @@ static int write_f(BlockBackend *blk, int argc, char
**argv)
return 0;
}
+ if (background && (bflag || cflag || zflag)) {
+ printf("-B cannot be specified together with -b, -c, or -z\n");
+ return 0;
+ }
+
offset = cvtnum(argv[optind]);
if (offset < 0) {
print_cvtnum_err(offset, argv[optind]);
@@ -1074,6 +1140,8 @@ static int write_f(BlockBackend *blk, int argc, char
**argv)
cnt = do_co_pwrite_zeroes(blk, offset, count, flags, &total);
} else if (cflag) {
cnt = do_write_compressed(blk, buf, offset, count, &total);
+ } else if (background) {
+ cnt = do_background_pwrite(blk, buf, offset, count, flags);
} else {
cnt = do_pwrite(blk, buf, offset, count, flags, &total);
}
@@ -1088,12 +1156,15 @@ static int write_f(BlockBackend *blk, int argc, char
**argv)
goto out;
}
- /* Finally, report back -- -C gives a parsable format */
- t2 = tsub(t2, t1);
- print_report("wrote", &t2, offset, count, total, cnt, Cflag);
+ if (!background) {
+ /* Finally, report back -- -C gives a parsable format */
+ t2 = tsub(t2, t1);
+ print_report("wrote", &t2, offset, count, total, cnt, Cflag);
+ }
out:
- if (!zflag) {
+ /* do_background_pwrite() takes ownership of the buffer */
+ if (!zflag && !background) {
qemu_io_free(buf);
}
--
2.13.5
- [Qemu-block] [PATCH 14/18] block/mirror: Distinguish active from passive ops, (continued)
- [Qemu-block] [PATCH 14/18] block/mirror: Distinguish active from passive ops, Max Reitz, 2017/09/13
- [Qemu-block] [PATCH 15/18] block/mirror: Add active mirroring, Max Reitz, 2017/09/13
- Re: [Qemu-block] [PATCH 15/18] block/mirror: Add active mirroring, Stefan Hajnoczi, 2017/09/14
- Re: [Qemu-block] [PATCH 15/18] block/mirror: Add active mirroring, Max Reitz, 2017/09/16
- Re: [Qemu-block] [PATCH 15/18] block/mirror: Add active mirroring, Stefan Hajnoczi, 2017/09/18
- Re: [Qemu-block] [PATCH 15/18] block/mirror: Add active mirroring, Max Reitz, 2017/09/18
- Re: [Qemu-block] [PATCH 15/18] block/mirror: Add active mirroring, Stefan Hajnoczi, 2017/09/19
- Re: [Qemu-block] [Qemu-devel] [PATCH 15/18] block/mirror: Add active mirroring, Daniel P. Berrange, 2017/09/19
- Re: [Qemu-block] [Qemu-devel] [PATCH 15/18] block/mirror: Add active mirroring, Stefan Hajnoczi, 2017/09/20
[Qemu-block] [PATCH 16/18] block/mirror: Add copy mode QAPI interface, Max Reitz, 2017/09/13
[Qemu-block] [PATCH 17/18] qemu-io: Add background write,
Max Reitz <=
- Re: [Qemu-block] [PATCH 17/18] qemu-io: Add background write, Fam Zheng, 2017/09/18
- Re: [Qemu-block] [PATCH 17/18] qemu-io: Add background write, Max Reitz, 2017/09/18
- Re: [Qemu-block] [PATCH 17/18] qemu-io: Add background write, Fam Zheng, 2017/09/19
- Re: [Qemu-block] [PATCH 17/18] qemu-io: Add background write, Max Reitz, 2017/09/21
- Re: [Qemu-block] [PATCH 17/18] qemu-io: Add background write, Fam Zheng, 2017/09/21
- Re: [Qemu-block] [PATCH 17/18] qemu-io: Add background write, Max Reitz, 2017/09/21
[Qemu-block] [PATCH 18/18] iotests: Add test for active mirroring, Max Reitz, 2017/09/13