Make it easier to control whether the BDRV_REQ_MAY_UNMAP flag
can be passed through a write_zeroes command, by adding a flag
to qemu-io. To be useful, the device has to be opened with
'qemu-io -d unmap' (or the just-added 'open -u' subcommand).
Signed-off-by: Eric Blake <ebl...@redhat.com>
---
qemu-io-cmds.c | 24 ++++++++++++++++++------
1 file changed, 18 insertions(+), 6 deletions(-)
diff --git a/qemu-io-cmds.c b/qemu-io-cmds.c
index 1e444cc..ca23459 100644
--- a/qemu-io-cmds.c
+++ b/qemu-io-cmds.c
@@ -454,6 +454,7 @@ typedef struct {
int64_t count;
int64_t *total;
bool fua;
+ bool unmap;
int ret;
bool done;
} CoWriteZeroes;
@@ -464,7 +465,8 @@ static void coroutine_fn co_write_zeroes_entry(void *opaque)
data->ret = blk_co_write_zeroes(data->blk, data->offset / BDRV_SECTOR_SIZE,
data->count / BDRV_SECTOR_SIZE,
- data->fua ? BDRV_REQ_FUA : 0);
+ (data->fua ? BDRV_REQ_FUA : 0) |
+ (data->unmap ? BDRV_REQ_MAY_UNMAP : 0));
data->done = true;
if (data->ret < 0) {
*data->total = data->ret;
@@ -475,7 +477,7 @@ static void coroutine_fn co_write_zeroes_entry(void *opaque)
}
static int do_co_write_zeroes(BlockBackend *blk, int64_t offset, int64_t count,
- bool fua, int64_t *total)
+ bool fua, bool unmap, int64_t *total)
{
Coroutine *co;
CoWriteZeroes data = {
@@ -484,6 +486,7 @@ static int do_co_write_zeroes(BlockBackend *blk, int64_t
offset, int64_t count,
.count = count,
.total = total,
.fua = fua,
+ .unmap = unmap,
.done = false,
};
@@ -959,6 +962,7 @@ static void write_help(void)
" -P, -- use different pattern to fill file\n"
" -C, -- report statistics in a machine parsable format\n"
" -q, -- quiet mode, do not show I/O statistics\n"
+" -u, -- with -z, allow unmapping\n"
" -z, -- write zeroes using blk_co_write_zeroes\n"
"\n");
}
@@ -971,7 +975,7 @@ static const cmdinfo_t write_cmd = {
.cfunc = write_f,
.argmin = 2,
.argmax = -1,
- .args = "[-bcCfqz] [-P pattern ] off len",
+ .args = "[-bcCfquz] [-P pattern ] off len",
.oneline = "writes a number of bytes at a specified offset",
.help = write_help,
};
@@ -980,7 +984,7 @@ static int write_f(BlockBackend *blk, int argc, char **argv)
{
struct timeval t1, t2;
int Cflag = 0, qflag = 0, bflag = 0, Pflag = 0, zflag = 0;
- int cflag = 0, fflag = 0;
+ int cflag = 0, fflag = 0, uflag = 0;
int c, cnt;
char *buf = NULL;
int64_t offset;
@@ -989,7 +993,7 @@ static int write_f(BlockBackend *blk, int argc, char **argv)
int64_t total = 0;
int pattern = 0xcd;
- while ((c = getopt(argc, argv, "bcCfpP:qz")) != -1) {
+ while ((c = getopt(argc, argv, "bcCfpP:quz")) != -1) {
switch (c) {
case 'b':
bflag = 1;
@@ -1016,6 +1020,9 @@ static int write_f(BlockBackend *blk, int argc, char
**argv)
case 'q':
qflag = 1;
break;
+ case 'u':
+ uflag = 1;
+ break;
case 'z':
zflag = 1;
break;
@@ -1038,6 +1045,11 @@ static int write_f(BlockBackend *blk, int argc, char
**argv)
return 0;
}
+ if (uflag && !zflag) {
+ printf("-u requires -z to be specified\n");
+ return 0;
+ }
+
if (zflag && Pflag) {
printf("-z and -P cannot be specified at the same time\n");
return 0;
@@ -1082,7 +1094,7 @@ static int write_f(BlockBackend *blk, int argc, char
**argv)
if (bflag) {
cnt = do_save_vmstate(blk, buf, offset, count, &total);
} else if (zflag) {
- cnt = do_co_write_zeroes(blk, offset, count, fflag, &total);
+ cnt = do_co_write_zeroes(blk, offset, count, fflag, uflag, &total);
} else if (cflag) {
cnt = do_write_compressed(blk, buf, offset, count, &total);
} else {
--
2.5.5
