file-posix: add tracking of the zone write pointers

Since Linux doesn't have a user API to issue zone append operations to
zoned devices from user space, the file-posix driver is modified to add
zone append emulation using regular writes. To do this, the file-posix
driver tracks the wp location of all zones of the device. It uses an
array of uint64_t. The most significant bit of each wp location indicates
if the zone type is conventional zones.

The zones wp can be changed due to the following operations issued:
- zone reset: change the wp to the start offset of that zone
- zone finish: change to the end location of that zone
- write to a zone
- zone append

Signed-off-by: Sam Li <faithilikerun@gmail.com>
Message-id: 20230508051510.177850-2-faithilikerun@gmail.com
[Fix errno propagation from handle_aiocb_zone_mgmt()
--Stefan]
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

2 files changed, 19 insertions, 0 deletions

diff --git a/include/block/block-common.h b/include/block/block-common.h
index 1576fcf2ed..93196229ac 100644
--- a/include/block/block-common.h
+++ b/include/block/block-common.h
@@ -118,6 +118,14 @@ typedef struct BlockZoneDescriptor {
     BlockZoneState state;
 } BlockZoneDescriptor;
 
+/*
+ * Track write pointers of a zone in bytes.
+ */
+typedef struct BlockZoneWps {
+    CoMutex colock;
+    uint64_t wp[];
+} BlockZoneWps;
+
 typedef struct BlockDriverInfo {
     /* in bytes, 0 if irrelevant */
     int cluster_size;
@@ -240,6 +248,12 @@ typedef enum {
 #define BDRV_SECTOR_BITS   9
 #define BDRV_SECTOR_SIZE   (1ULL << BDRV_SECTOR_BITS)
 
+/*
+ * Get the first most significant bit of wp. If it is zero, then
+ * the zone type is SWR.
+ */
+#define BDRV_ZT_IS_CONV(wp)    (wp & (1ULL << 63))
+
 #define BDRV_REQUEST_MAX_SECTORS MIN_CONST(SIZE_MAX >> BDRV_SECTOR_BITS, \
                                            INT_MAX >> BDRV_SECTOR_BITS)
 #define BDRV_REQUEST_MAX_BYTES (BDRV_REQUEST_MAX_SECTORS << BDRV_SECTOR_BITS)
diff --git a/include/block/block_int-common.h b/include/block/block_int-common.h
index e6975d3933..1674b4745d 100644
--- a/include/block/block_int-common.h
+++ b/include/block/block_int-common.h
@@ -891,6 +891,8 @@ typedef struct BlockLimits {
 
     /* maximum number of active zones */
     uint32_t max_active_zones;
+
+    uint32_t write_granularity;
 } BlockLimits;
 
 typedef struct BdrvOpBlocker BdrvOpBlocker;
@@ -1252,6 +1254,9 @@ struct BlockDriverState {
     CoMutex bsc_modify_lock;
     /* Always non-NULL, but must only be dereferenced under an RCU read guard */
     BdrvBlockStatusCache *block_status_cache;
+
+    /* array of write pointers' location of each zone in the zoned device. */
+    BlockZoneWps *wps;
 };
 
 struct BlockBackendRootState {