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 <xiaolong.ye@xxxxxxxxx>
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
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 309e26c9dddb..f40b5da5d467 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);
}
--
2.14.2
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