From: Dave Chinner dchinner@redhat.com
mainline-inclusion from mainline-v5.13-rc4 commit 0431d926b399d74f1cde2c355d48289c6d7fa882 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I4KIAO CVE: NA
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
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The new checkpoint cache flush mechanism requires us to issue an unconditional cache flush before we start a new checkpoint. We don't want to block for this if we can help it, and we have a fair chunk of CPU work to do between starting the checkpoint and issuing the first journal IO.
Hence it makes sense to amortise the latency cost of the cache flush by issuing it asynchronously and then waiting for it only when we need to issue the first IO in the transaction.
To do this, we need async cache flush primitives to submit the cache flush bio and to wait on it. The block layer has no such primitives for filesystems, so roll our own for the moment.
Signed-off-by: Dave Chinner dchinner@redhat.com Reviewed-by: Brian Foster bfoster@redhat.com Reviewed-by: Darrick J. Wong djwong@kernel.org Reviewed-by: Allison Henderson allison.henderson@oracle.com Signed-off-by: Darrick J. Wong djwong@kernel.org Signed-off-by: Guo Xuenan guoxuenan@huawei.com Reviewed-by: Lihong Kou koulihong@huawei.com Reviewed-by: Zhang Yi yi.zhang@huawei.com Signed-off-by: Zheng Zengkai zhengzengkai@huawei.com --- fs/xfs/xfs_bio_io.c | 35 +++++++++++++++++++++++++++++++++++ fs/xfs/xfs_linux.h | 2 ++ 2 files changed, 37 insertions(+)
diff --git a/fs/xfs/xfs_bio_io.c b/fs/xfs/xfs_bio_io.c index e2148f2d5d6b..b20a9b639acb 100644 --- a/fs/xfs/xfs_bio_io.c +++ b/fs/xfs/xfs_bio_io.c @@ -9,6 +9,41 @@ static inline unsigned int bio_max_vecs(unsigned int count) return min_t(unsigned, howmany(count, PAGE_SIZE), BIO_MAX_PAGES); }
+static void +xfs_flush_bdev_async_endio( + struct bio *bio) +{ + complete(bio->bi_private); +} + +/* + * Submit a request for an async cache flush to run. If the request queue does + * not require flush operations, just skip it altogether. If the caller needs + * to wait for the flush completion at a later point in time, they must supply a + * valid completion. This will be signalled when the flush completes. The + * caller never sees the bio that is issued here. + */ +void +xfs_flush_bdev_async( + struct bio *bio, + struct block_device *bdev, + struct completion *done) +{ + struct request_queue *q = bdev->bd_disk->queue; + + if (!test_bit(QUEUE_FLAG_WC, &q->queue_flags)) { + complete(done); + return; + } + + bio_init(bio, NULL, 0); + bio_set_dev(bio, bdev); + bio->bi_opf = REQ_OP_WRITE | REQ_PREFLUSH | REQ_SYNC; + bio->bi_private = done; + bio->bi_end_io = xfs_flush_bdev_async_endio; + + submit_bio(bio); +} int xfs_rw_bdev( struct block_device *bdev, diff --git a/fs/xfs/xfs_linux.h b/fs/xfs/xfs_linux.h index 5b7a1e201559..08e3bd3f859a 100644 --- a/fs/xfs/xfs_linux.h +++ b/fs/xfs/xfs_linux.h @@ -197,6 +197,8 @@ static inline uint64_t howmany_64(uint64_t x, uint32_t y)
int xfs_rw_bdev(struct block_device *bdev, sector_t sector, unsigned int count, char *data, unsigned int op); +void xfs_flush_bdev_async(struct bio *bio, struct block_device *bdev, + struct completion *done);
#define ASSERT_ALWAYS(expr) \ (likely(expr) ? (void)0 : assfail(NULL, #expr, __FILE__, __LINE__))