This commit adds support to the BlockDriverState type to keep track
of the devices' I/O status.
There are three possible status: BDRV_IOS_OK (no error so far),
BDRV_IOS_ENOSPC (no space error) and BDRV_IOS_FAILED (any other error).
The distinction between no space and other errors is important because
a management application may want to watch for no space in order to
extend the host's underline device and put the VM to run again.
Qemu devices supporting the I/O status feature have to enable it
explicitly by calling bdrv_iostatus_enable() _and_ have to be
configured to stop the VM on errors (ie. werror=stop|enospc or
rerror=stop).
In case of multiple errors being triggered in sequence only the first
one is stored. The I/O status is set back to BDRV_IOS_OK when the
'cont' command is issued.
Next commits will add support to some devices and extend the
query-block/info block commands with the I/O status information.
Signed-off-by: Luiz Capitulino <lcapitul...@redhat.com>
---
block.c | 32 ++++++++++++++++++++++++++++++++
block.h | 9 +++++++++
block_int.h | 1 +
monitor.c | 6 ++++++
4 files changed, 48 insertions(+), 0 deletions(-)
diff --git a/block.c b/block.c
index 03a21d8..c54caf2 100644
--- a/block.c
+++ b/block.c
@@ -220,6 +220,7 @@ BlockDriverState *bdrv_new(const char *device_name)
if (device_name[0] != '\0') {
QTAILQ_INSERT_TAIL(&bdrv_states, bs, list);
}
+ bs->iostatus = BDRV_IOS_INVAL;
return bs;
}
@@ -3165,6 +3166,37 @@ int bdrv_in_use(BlockDriverState *bs)
return bs->in_use;
}
+void bdrv_iostatus_enable(BlockDriverState *bs)
+{
+ assert(bs->iostatus == BDRV_IOS_INVAL);
+ bs->iostatus = BDRV_IOS_OK;
+}
+
+/* The I/O status is only enabled if the drive explicitly
+ * enables it _and_ the VM is configured to stop on errors */
+bool bdrv_iostatus_is_enabled(const BlockDriverState *bs)
+{
+ return (bs->iostatus != BDRV_IOS_INVAL &&
+ (bs->on_write_error == BLOCK_ERR_STOP_ENOSPC ||
+ bs->on_write_error == BLOCK_ERR_STOP_ANY ||
+ bs->on_read_error == BLOCK_ERR_STOP_ANY));
+}
+
+void bdrv_iostatus_reset(BlockDriverState *bs)
+{
+ if (bdrv_iostatus_is_enabled(bs)) {
+ bs->iostatus = BDRV_IOS_OK;
+ }
+}
+
+void bdrv_iostatus_update(BlockDriverState *bs, int error)
+{
+ if (bdrv_iostatus_is_enabled(bs) && bs->iostatus == BDRV_IOS_OK) {
+ bs->iostatus = (abs(error) == ENOSPC) ? BDRV_IOS_ENOSPC :
+ BDRV_IOS_FAILED;
+ }
+}
+
void
bdrv_acct_start(BlockDriverState *bs, BlockAcctCookie *cookie, int64_t bytes,
enum BlockAcctType type)
diff --git a/block.h b/block.h
index 3ac0b94..24914e0 100644
--- a/block.h
+++ b/block.h
@@ -51,6 +51,15 @@ typedef enum {
BDRV_ACTION_REPORT, BDRV_ACTION_IGNORE, BDRV_ACTION_STOP
} BlockMonEventAction;
+typedef enum {
+ BDRV_IOS_INVAL, BDRV_IOS_OK, BDRV_IOS_FAILED, BDRV_IOS_ENOSPC,
+ BDRV_IOS_MAX
+} BlockIOStatus;
+
+void bdrv_iostatus_enable(BlockDriverState *bs);
+void bdrv_iostatus_reset(BlockDriverState *bs);
+bool bdrv_iostatus_is_enabled(const BlockDriverState *bs);
+void bdrv_iostatus_update(BlockDriverState *bs, int error);
void bdrv_mon_event(const BlockDriverState *bdrv,
BlockMonEventAction action, int is_read);
void bdrv_info_print(Monitor *mon, const QObject *data);
diff --git a/block_int.h b/block_int.h
index 8a72b80..600801d 100644
--- a/block_int.h
+++ b/block_int.h
@@ -203,6 +203,7 @@ struct BlockDriverState {
drivers. They are not used by the block driver */
int cyls, heads, secs, translation;
BlockErrorAction on_read_error, on_write_error;
+ BlockIOStatus iostatus;
char device_name[32];
unsigned long *dirty_bitmap;
int64_t dirty_count;
diff --git a/monitor.c b/monitor.c
index 9807005..69f1b3c 100644
--- a/monitor.c
+++ b/monitor.c
@@ -1302,6 +1302,11 @@ struct bdrv_iterate_context {
int err;
};
+static void iostatus_bdrv_it(void *opaque, BlockDriverState *bs)
+{
+ bdrv_iostatus_reset(bs);
+}
+
/**
* do_cont(): Resume emulation.
*/
@@ -1318,6 +1323,7 @@ static int do_cont(Monitor *mon, const QDict *qdict,
QObject **ret_data)
return -1;
}
+ bdrv_iterate(iostatus_bdrv_it, NULL);
bdrv_iterate(encrypted_bdrv_it, &context);
/* only resume the vm if all keys are set and valid */
if (!context.err) {
--
1.7.7.rc0.72.g4b5ea
