From 942491c9e6d631c012f3c4ea8e7777b0b02edeab Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Mon, 23 Oct 2017 18:31:50 -0700 Subject: [PATCH] xfs: fix AIM7 regression Apparently our current rwsem code doesn't like doing the trylock, then lock for real scheme. So change our read/write methods to just do the trylock for the RWF_NOWAIT case. This fixes a ~25% regression in AIM7. Fixes: 91f9943e ("fs: support RWF_NOWAIT for buffered reads") Reported-by: kernel test robot Signed-off-by: Christoph Hellwig Reviewed-by: Darrick J. Wong Signed-off-by: Darrick J. Wong --- fs/xfs/xfs_file.c | 21 +++++++++++++-------- 1 file changed, 13 insertions(+), 8 deletions(-) diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c index 56d0e526870c..6526ef0e2a23 100644 --- a/fs/xfs/xfs_file.c +++ b/fs/xfs/xfs_file.c @@ -237,11 +237,13 @@ xfs_file_dax_read( if (!count) return 0; /* skip atime */ - if (!xfs_ilock_nowait(ip, XFS_IOLOCK_SHARED)) { - if (iocb->ki_flags & IOCB_NOWAIT) + if (iocb->ki_flags & IOCB_NOWAIT) { + if (!xfs_ilock_nowait(ip, XFS_IOLOCK_SHARED)) return -EAGAIN; + } else { xfs_ilock(ip, XFS_IOLOCK_SHARED); } + ret = dax_iomap_rw(iocb, to, &xfs_iomap_ops); xfs_iunlock(ip, XFS_IOLOCK_SHARED); @@ -259,9 +261,10 @@ xfs_file_buffered_aio_read( trace_xfs_file_buffered_read(ip, iov_iter_count(to), iocb->ki_pos); - if (!xfs_ilock_nowait(ip, XFS_IOLOCK_SHARED)) { - if (iocb->ki_flags & IOCB_NOWAIT) + if (iocb->ki_flags & IOCB_NOWAIT) { + if (!xfs_ilock_nowait(ip, XFS_IOLOCK_SHARED)) return -EAGAIN; + } else { xfs_ilock(ip, XFS_IOLOCK_SHARED); } ret = generic_file_read_iter(iocb, to); @@ -552,9 +555,10 @@ xfs_file_dio_aio_write( iolock = XFS_IOLOCK_SHARED; } - if (!xfs_ilock_nowait(ip, iolock)) { - if (iocb->ki_flags & IOCB_NOWAIT) + if (iocb->ki_flags & IOCB_NOWAIT) { + if (!xfs_ilock_nowait(ip, iolock)) return -EAGAIN; + } else { xfs_ilock(ip, iolock); } @@ -606,9 +610,10 @@ xfs_file_dax_write( size_t count; loff_t pos; - if (!xfs_ilock_nowait(ip, iolock)) { - if (iocb->ki_flags & IOCB_NOWAIT) + if (iocb->ki_flags & IOCB_NOWAIT) { + if (!xfs_ilock_nowait(ip, iolock)) return -EAGAIN; + } else { xfs_ilock(ip, iolock); }