On 5/23/23 23:39, Fabiano Rosas wrote:
> From: João Silva <jsi...@suse.de>
>
> The fstat call can take a long time to finish when running over
> NFS. Add a version of it that runs in the thread pool.
>
> Adapt one of its users, raw_co_get_allocated_file size to use the new
> version. That function is called via QMP under the qemu_global_mutex
> so it has a large chance of blocking VCPU threads in case it takes too
> long to finish.
>
> Signed-off-by: João Silva <jsi...@suse.de>
> Signed-off-by: Fabiano Rosas <faro...@suse.de>
> ---
> block/file-posix.c | 40 +++++++++++++++++++++++++++++++++++++---
> include/block/raw-aio.h | 4 +++-
> 2 files changed, 40 insertions(+), 4 deletions(-)
>
> diff --git a/block/file-posix.c b/block/file-posix.c
> index 0ab158efba..0a29a6cc43 100644
> --- a/block/file-posix.c
> +++ b/block/file-posix.c
> @@ -227,6 +227,9 @@ typedef struct RawPosixAIOData {
> struct {
> unsigned long op;
> } zone_mgmt;
> + struct {
> + struct stat *st;
> + } fstat;
> };
> } RawPosixAIOData;
>
> @@ -2644,6 +2647,34 @@ static void raw_close(BlockDriverState *bs)
> }
> }
>
> +static int handle_aiocb_fstat(void *opaque)
> +{
> + RawPosixAIOData *aiocb = opaque;
> +
> + if (fstat(aiocb->aio_fildes, aiocb->fstat.st) < 0) {
> + return -errno;
> + }
> +
> + return 0;
> +}
> +
> +static int coroutine_fn raw_co_fstat(BlockDriverState *bs, struct stat *st)
> +{
> + BDRVRawState *s = bs->opaque;
> + RawPosixAIOData acb;
> +
> + acb = (RawPosixAIOData) {
> + .bs = bs,
> + .aio_fildes = s->fd,
> + .aio_type = QEMU_AIO_FSTAT,
> + .fstat = {
> + .st = st,
> + },
> + };
> +
> + return raw_thread_pool_submit(handle_aiocb_fstat, &acb);
> +}
> +
> /**
> * Truncates the given regular file @fd to @offset and, when growing, fills
> the
> * new space according to @prealloc.
> @@ -2883,11 +2914,14 @@ static int64_t coroutine_fn
> raw_co_getlength(BlockDriverState *bs)
> static int64_t coroutine_fn raw_co_get_allocated_file_size(BlockDriverState
> *bs)
> {
> struct stat st;
> - BDRVRawState *s = bs->opaque;
> + int ret;
>
> - if (fstat(s->fd, &st) < 0) {
> - return -errno;
> + ret = raw_co_fstat(bs, &st);
> +
> + if (ret) {
> + return ret;
> }
> +
> return (int64_t)st.st_blocks * 512;
> }
>
> diff --git a/include/block/raw-aio.h b/include/block/raw-aio.h
> index 0fe85ade77..7dc6d24e21 100644
> --- a/include/block/raw-aio.h
> +++ b/include/block/raw-aio.h
> @@ -31,6 +31,7 @@
> #define QEMU_AIO_ZONE_REPORT 0x0100
> #define QEMU_AIO_ZONE_MGMT 0x0200
> #define QEMU_AIO_ZONE_APPEND 0x0400
> +#define QEMU_AIO_FSTAT 0x0800
> #define QEMU_AIO_TYPE_MASK \
> (QEMU_AIO_READ | \
> QEMU_AIO_WRITE | \
> @@ -42,7 +43,8 @@
> QEMU_AIO_TRUNCATE | \
> QEMU_AIO_ZONE_REPORT | \
> QEMU_AIO_ZONE_MGMT | \
> - QEMU_AIO_ZONE_APPEND)
> + QEMU_AIO_ZONE_APPEND | \
> + QEMU_AIO_FSTAT)
>
> /* AIO flags */
> #define QEMU_AIO_MISALIGNED 0x1000
Reviewed-by: Claudio Fontana <cfont...@suse.de>
