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* [Qemu-devel] [PATCH v6] sheepdog: add discard/trim support for sheepdog
@ 2013-04-18  5:44 Liu Yuan
  2013-04-18  5:50 ` [Qemu-devel] [PATCH v7] " Liu Yuan
  2013-04-18  8:24 ` [Qemu-devel] [PATCH v8] " Liu Yuan
  0 siblings, 2 replies; 6+ messages in thread
From: Liu Yuan @ 2013-04-18  5:44 UTC (permalink / raw)
  To: qemu-devel
  Cc: Kevin Wolf, Paolo Bonzini, sheepdog, Stefan Hajnoczi,
	MORITA Kazutaka

From: Liu Yuan <tailai.ly@taobao.com>

The 'TRIM' command from VM that is to release underlying data storage for
better thin-provision is already supported by the Sheepdog.

This patch adds the TRIM support at QEMU part.

For older Sheepdog that doesn't support it, we return 0(success) to upper layer.

Cc: MORITA Kazutaka <morita.kazutaka@lab.ntt.co.jp>
Cc: Kevin Wolf <kwolf@redhat.com>
Cc: Stefan Hajnoczi <stefanha@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Liu Yuan <tailai.ly@taobao.com>
---
v6:
 - add boolean indicator to disable discard operation when not supported by the
   server
v5:
 - adjust macro numbering
v4:
 - adjust discard macro
 - return success when operation is not supported by sheep
 - add coroutine_fn marker
v3:
 - fix a silly accidental deletion of 'default' in switch clause.
v2:
 - skip the object when it is not allocated

 block/sheepdog.c |   62 +++++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 61 insertions(+), 1 deletion(-)

diff --git a/block/sheepdog.c b/block/sheepdog.c
index 1c5b532..57858b6 100644
--- a/block/sheepdog.c
+++ b/block/sheepdog.c
@@ -27,6 +27,8 @@
 #define SD_OP_CREATE_AND_WRITE_OBJ  0x01
 #define SD_OP_READ_OBJ       0x02
 #define SD_OP_WRITE_OBJ      0x03
+/* 0x04 is used internally by Sheepdog */
+#define SD_OP_DISCARD_OBJ    0x05
 
 #define SD_OP_NEW_VDI        0x11
 #define SD_OP_LOCK_VDI       0x12
@@ -184,6 +186,8 @@ typedef struct SheepdogInode {
     uint32_t data_vdi_id[MAX_DATA_OBJS];
 } SheepdogInode;
 
+static bool discard_supported = true;
+
 /*
  * 64 bit FNV-1a non-zero initial basis
  */
@@ -269,6 +273,7 @@ enum AIOCBState {
     AIOCB_WRITE_UDATA,
     AIOCB_READ_UDATA,
     AIOCB_FLUSH_CACHE,
+    AIOCB_DISCARD_OBJ,
 };
 
 struct SheepdogAIOCB {
@@ -656,7 +661,7 @@ static void coroutine_fn aio_read_response(void *opaque)
     int ret;
     AIOReq *aio_req = NULL;
     SheepdogAIOCB *acb;
-    unsigned long idx;
+    uint64_t idx;
 
     if (QLIST_EMPTY(&s->inflight_aio_head)) {
         goto out;
@@ -727,6 +732,21 @@ static void coroutine_fn aio_read_response(void *opaque)
             rsp.result = SD_RES_SUCCESS;
         }
         break;
+    case AIOCB_DISCARD_OBJ:
+        switch (rsp.result) {
+        case SD_RES_INVALID_PARMS:
+            error_report("you are running the old sheep that doesn't support "
+                         "discard command.\n");
+            rsp.result = SD_RES_SUCCESS;
+            discard_supported = false;
+            break;
+        case SD_RES_SUCCESS:
+            idx = data_oid_to_idx(aio_req->oid);
+            s->inode.data_vdi_id[idx] = 0;
+            break;
+        default:
+            break;
+        }
     }
 
     if (rsp.result != SD_RES_SUCCESS) {
@@ -1016,6 +1036,9 @@ static int coroutine_fn add_aio_request(BDRVSheepdogState *s, AIOReq *aio_req,
         wlen = datalen;
         hdr.flags = SD_FLAG_CMD_WRITE | flags;
         break;
+    case AIOCB_DISCARD_OBJ:
+        hdr.opcode = SD_OP_DISCARD_OBJ;
+        break;
     }
 
     if (s->cache_flags) {
@@ -1633,6 +1656,15 @@ static int coroutine_fn sd_co_rw_vector(void *p)
                 flags = SD_FLAG_CMD_COW;
             }
             break;
+        case AIOCB_DISCARD_OBJ:
+            /*
+             * We discard the object only when the whole object is
+             * 1) allocated 2) trimmed. Otherwise, simply skip it.
+             */
+            if (len != SD_DATA_OBJ_SIZE || inode->data_vdi_id[idx] == 0) {
+                goto done;
+            }
+            break;
         default:
             break;
         }
@@ -2078,6 +2110,31 @@ static int sd_load_vmstate(BlockDriverState *bs, uint8_t *data,
 }
 
 
+static coroutine_fn int sd_co_discard(BlockDriverState *bs, int64_t sector_num,
+                                      int nb_sectors)
+{
+    SheepdogAIOCB *acb;
+    QEMUIOVector dummy;
+    int ret;
+
+    if (!discard_supported)
+            return 0;
+
+    acb = sd_aio_setup(bs, &dummy, sector_num, nb_sectors);
+    acb->aiocb_type = AIOCB_DISCARD_OBJ;
+    acb->aio_done_func = sd_finish_aiocb;
+
+    ret = sd_co_rw_vector(acb);
+    if (ret <= 0) {
+        qemu_aio_release(acb);
+        return ret;
+    }
+
+    qemu_coroutine_yield();
+
+    return acb->ret;
+}
+
 static QEMUOptionParameter sd_create_options[] = {
     {
         .name = BLOCK_OPT_SIZE,
@@ -2110,6 +2167,7 @@ static BlockDriver bdrv_sheepdog = {
     .bdrv_co_readv  = sd_co_readv,
     .bdrv_co_writev = sd_co_writev,
     .bdrv_co_flush_to_disk  = sd_co_flush_to_disk,
+    .bdrv_co_discard = sd_co_discard,
 
     .bdrv_snapshot_create   = sd_snapshot_create,
     .bdrv_snapshot_goto     = sd_snapshot_goto,
@@ -2135,6 +2193,7 @@ static BlockDriver bdrv_sheepdog_tcp = {
     .bdrv_co_readv  = sd_co_readv,
     .bdrv_co_writev = sd_co_writev,
     .bdrv_co_flush_to_disk  = sd_co_flush_to_disk,
+    .bdrv_co_discard = sd_co_discard,
 
     .bdrv_snapshot_create   = sd_snapshot_create,
     .bdrv_snapshot_goto     = sd_snapshot_goto,
@@ -2160,6 +2219,7 @@ static BlockDriver bdrv_sheepdog_unix = {
     .bdrv_co_readv  = sd_co_readv,
     .bdrv_co_writev = sd_co_writev,
     .bdrv_co_flush_to_disk  = sd_co_flush_to_disk,
+    .bdrv_co_discard = sd_co_discard,
 
     .bdrv_snapshot_create   = sd_snapshot_create,
     .bdrv_snapshot_goto     = sd_snapshot_goto,
-- 
1.7.9.5

^ permalink raw reply related	[flat|nested] 6+ messages in thread
end of thread, other threads:[~2013-04-18 11:05 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2013-04-18  5:44 [Qemu-devel] [PATCH v6] sheepdog: add discard/trim support for sheepdog Liu Yuan
2013-04-18  5:50 ` [Qemu-devel] [PATCH v7] " Liu Yuan
2013-04-18  7:37   ` Stefan Hajnoczi
2013-04-18  7:41     ` Liu Yuan
2013-04-18  8:24 ` [Qemu-devel] [PATCH v8] " Liu Yuan
2013-04-18 11:05   ` Stefan Hajnoczi

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