Re: [Qemu-block] [PATCH 09/18] nfs: use bdrv_poll_while and bdrv_wakeup

[Stefan Hajnoczi]

On Thu, Oct 13, 2016 at 07:34:13PM +0200, Paolo Bonzini wrote:
> These will make it possible to use nfs_get_allocated_file_size on
> a file that is not in the main AioContext.
> 
> Signed-off-by: Paolo Bonzini 
> ---
>  block/nfs.c | 47 +--
>  1 file changed, 29 insertions(+), 18 deletions(-)

Reviewed-by: Stefan Hajnoczi 


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[Qemu-block] [PATCH 09/18] nfs: use bdrv_poll_while and bdrv_wakeup

[Paolo Bonzini]

These will make it possible to use nfs_get_allocated_file_size on
a file that is not in the main AioContext.

Signed-off-by: Paolo Bonzini 
---
 block/nfs.c | 47 +--
 1 file changed, 29 insertions(+), 18 deletions(-)

diff --git a/block/nfs.c b/block/nfs.c
index c8df8d8..e5c7e1a 100644
--- a/block/nfs.c
+++ b/block/nfs.c
@@ -52,6 +52,7 @@ typedef struct NFSClient {
 } NFSClient;
 
 typedef struct NFSRPC {
+BlockDriverState *bs;
 int ret;
 int complete;
 QEMUIOVector *iov;
@@ -90,11 +91,12 @@ static void nfs_process_write(void *arg)
 nfs_set_events(client);
 }
 
-static void nfs_co_init_task(NFSClient *client, NFSRPC *task)
+static void nfs_co_init_task(BlockDriverState *bs, NFSRPC *task)
 {
 *task = (NFSRPC) {
 .co = qemu_coroutine_self(),
-.client = client,
+.bs = bs,
+.client = bs->opaque,
 };
 }
 
@@ -111,6 +113,7 @@ nfs_co_generic_cb(int ret, struct nfs_context *nfs, void 
*data,
 {
 NFSRPC *task = private_data;
 task->ret = ret;
+assert(!task->st);
 if (task->ret > 0 && task->iov) {
 if (task->ret <= task->iov->size) {
 qemu_iovec_from_buf(task->iov, 0, data, task->ret);
@@ -118,18 +121,11 @@ nfs_co_generic_cb(int ret, struct nfs_context *nfs, void 
*data,
 task->ret = -EIO;
 }
 }
-if (task->ret == 0 && task->st) {
-memcpy(task->st, data, sizeof(struct stat));
-}
 if (task->ret < 0) {
 error_report("NFS Error: %s", nfs_get_error(nfs));
 }
-if (task->co) {
-aio_bh_schedule_oneshot(task->client->aio_context,
-nfs_co_generic_bh_cb, task);
-} else {
-task->complete = 1;
-}
+aio_bh_schedule_oneshot(task->client->aio_context,
+nfs_co_generic_bh_cb, task);
 }
 
 static int coroutine_fn nfs_co_readv(BlockDriverState *bs,
@@ -139,7 +135,7 @@ static int coroutine_fn nfs_co_readv(BlockDriverState *bs,
 NFSClient *client = bs->opaque;
 NFSRPC task;
 
-nfs_co_init_task(client, );
+nfs_co_init_task(bs, );
 task.iov = iov;
 
 if (nfs_pread_async(client->context, client->fh,
@@ -174,7 +170,7 @@ static int coroutine_fn nfs_co_writev(BlockDriverState *bs,
 NFSRPC task;
 char *buf = NULL;
 
-nfs_co_init_task(client, );
+nfs_co_init_task(bs, );
 
 buf = g_try_malloc(nb_sectors * BDRV_SECTOR_SIZE);
 if (nb_sectors && buf == NULL) {
@@ -210,7 +206,7 @@ static int coroutine_fn nfs_co_flush(BlockDriverState *bs)
 NFSClient *client = bs->opaque;
 NFSRPC task;
 
-nfs_co_init_task(client, );
+nfs_co_init_task(bs, );
 
 if (nfs_fsync_async(client->context, client->fh, nfs_co_generic_cb,
 ) != 0) {
@@ -496,6 +492,22 @@ static int nfs_has_zero_init(BlockDriverState *bs)
 return client->has_zero_init;
 }
 
+static void
+nfs_get_allocated_file_size_cb(int ret, struct nfs_context *nfs, void *data,
+   void *private_data)
+{
+NFSRPC *task = private_data;
+task->ret = ret;
+if (task->ret == 0) {
+memcpy(task->st, data, sizeof(struct stat));
+}
+if (task->ret < 0) {
+error_report("NFS Error: %s", nfs_get_error(nfs));
+}
+task->complete = 1;
+bdrv_wakeup(task->bs);
+}
+
 static int64_t nfs_get_allocated_file_size(BlockDriverState *bs)
 {
 NFSClient *client = bs->opaque;
@@ -507,16 +519,15 @@ static int64_t 
nfs_get_allocated_file_size(BlockDriverState *bs)
 return client->st_blocks * 512;
 }
 
+task.bs = bs;
 task.st = 
-if (nfs_fstat_async(client->context, client->fh, nfs_co_generic_cb,
+if (nfs_fstat_async(client->context, client->fh, 
nfs_get_allocated_file_size_cb,
 ) != 0) {
 return -ENOMEM;
 }
 
 nfs_set_events(client);
-while (!task.complete) {
-aio_poll(client->aio_context, true);
-}
+bdrv_poll_while(bs, !task.complete);
 
 return (task.ret < 0 ? task.ret : st.st_blocks * 512);
 }
-- 
2.7.4