From 53711e6aad8a6e40426ccef25e911d3cad93220a Mon Sep 17 00:00:00 2001 From: Kevin Wolf Date: Wed, 25 Jun 2025 10:50:19 +0200 Subject: [PATCH 12/33] file-posix: Fix aio=threads performance regression after enablign FUA RH-Author: Kevin Wolf RH-MergeRequest: 392: file-posix: Fix aio=threads performance regression after enabling FUA RH-Jira: RHEL-96854 RH-Acked-by: Stefan Hajnoczi RH-Acked-by: Hanna Czenczek RH-Commit: [1/1] e523c0305e3072d59ad6454afc690cabfcfb86b2 (kmwolf/centos-qemu-kvm) For aio=threads, we're currently not implementing REQ_FUA in any useful way, but just do a separate raw_co_flush_to_disk() call. This changes behaviour compared to the old state, which used bdrv_co_flush() with its optimisations. As a quick fix, call bdrv_co_flush() again like before. Eventually, we can use pwritev2() to make use of RWF_DSYNC if available, but we'll still have to keep this code path as a fallback, so this fix is required either way. While the fix itself is a one-liner, some new graph locking annotations are needed to convince TSA that the locking is correct. Cc: qemu-stable@nongnu.org Fixes: 984a32f17e8d ("file-posix: Support FUA writes") Buglink: https://issues.redhat.com/browse/RHEL-96854 Reported-by: Tingting Mao Signed-off-by: Kevin Wolf Message-ID: <20250625085019.27735-1-kwolf@redhat.com> Reviewed-by: Eric Blake Signed-off-by: Kevin Wolf (cherry picked from commit d402da1360c2240e81f0e5fc80ddbfc6238e0da8) Signed-off-by: Kevin Wolf --- block/file-posix.c | 29 +++++++++++++++-------------- 1 file changed, 15 insertions(+), 14 deletions(-) diff --git a/block/file-posix.c b/block/file-posix.c index 77a35d9ae9..d3c7dcc7e4 100644 --- a/block/file-posix.c +++ b/block/file-posix.c @@ -2573,9 +2573,9 @@ static inline bool raw_check_linux_aio(BDRVRawState *s) } #endif -static int coroutine_fn raw_co_prw(BlockDriverState *bs, int64_t *offset_ptr, - uint64_t bytes, QEMUIOVector *qiov, int type, - int flags) +static int coroutine_fn GRAPH_RDLOCK +raw_co_prw(BlockDriverState *bs, int64_t *offset_ptr, uint64_t bytes, + QEMUIOVector *qiov, int type, int flags) { BDRVRawState *s = bs->opaque; RawPosixAIOData acb; @@ -2634,7 +2634,7 @@ static int coroutine_fn raw_co_prw(BlockDriverState *bs, int64_t *offset_ptr, ret = raw_thread_pool_submit(handle_aiocb_rw, &acb); if (ret == 0 && (flags & BDRV_REQ_FUA)) { /* TODO Use pwritev2() instead if it's available */ - ret = raw_co_flush_to_disk(bs); + ret = bdrv_co_flush(bs); } goto out; /* Avoid the compiler err of unused label */ @@ -2669,16 +2669,16 @@ out: return ret; } -static int coroutine_fn raw_co_preadv(BlockDriverState *bs, int64_t offset, - int64_t bytes, QEMUIOVector *qiov, - BdrvRequestFlags flags) +static int coroutine_fn GRAPH_RDLOCK +raw_co_preadv(BlockDriverState *bs, int64_t offset, int64_t bytes, + QEMUIOVector *qiov, BdrvRequestFlags flags) { return raw_co_prw(bs, &offset, bytes, qiov, QEMU_AIO_READ, flags); } -static int coroutine_fn raw_co_pwritev(BlockDriverState *bs, int64_t offset, - int64_t bytes, QEMUIOVector *qiov, - BdrvRequestFlags flags) +static int coroutine_fn GRAPH_RDLOCK +raw_co_pwritev(BlockDriverState *bs, int64_t offset, int64_t bytes, + QEMUIOVector *qiov, BdrvRequestFlags flags) { return raw_co_prw(bs, &offset, bytes, qiov, QEMU_AIO_WRITE, flags); } @@ -3615,10 +3615,11 @@ static int coroutine_fn raw_co_zone_mgmt(BlockDriverState *bs, BlockZoneOp op, #endif #if defined(CONFIG_BLKZONED) -static int coroutine_fn raw_co_zone_append(BlockDriverState *bs, - int64_t *offset, - QEMUIOVector *qiov, - BdrvRequestFlags flags) { +static int coroutine_fn GRAPH_RDLOCK +raw_co_zone_append(BlockDriverState *bs, + int64_t *offset, + QEMUIOVector *qiov, + BdrvRequestFlags flags) { assert(flags == 0); int64_t zone_size_mask = bs->bl.zone_size - 1; int64_t iov_len = 0; -- 2.39.3