linux-ext4 - [PATCH 12/29] xfs: enforce GFP_NOIO implicitly during nowait time update

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Date:   Fri, 25 Aug 2023 21:54:14 +0800
From:   Hao Xu <hao.xu@...ux.dev>
To:     io-uring@...r.kernel.org, Jens Axboe <axboe@...nel.dk>
Cc:     Dominique Martinet <asmadeus@...ewreck.org>,
        Pavel Begunkov <asml.silence@...il.com>,
        Christian Brauner <brauner@...nel.org>,
        Alexander Viro <viro@...iv.linux.org.uk>,
        Stefan Roesch <shr@...com>, Clay Harris <bugs@...ycon.org>,
        Dave Chinner <david@...morbit.com>,
        "Darrick J . Wong" <djwong@...nel.org>,
        linux-fsdevel@...r.kernel.org, linux-xfs@...r.kernel.org,
        linux-ext4@...r.kernel.org, linux-cachefs@...hat.com,
        ecryptfs@...r.kernel.org, linux-nfs@...r.kernel.org,
        linux-unionfs@...r.kernel.org, bpf@...r.kernel.org,
        netdev@...r.kernel.org, linux-s390@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-block@...r.kernel.org,
        linux-btrfs@...r.kernel.org, codalist@...a.cs.cmu.edu,
        linux-f2fs-devel@...ts.sourceforge.net, cluster-devel@...hat.com,
        linux-mm@...ck.org, linux-nilfs@...r.kernel.org,
        devel@...ts.orangefs.org, linux-cifs@...r.kernel.org,
        samba-technical@...ts.samba.org, linux-mtd@...ts.infradead.org,
        Wanpeng Li <wanpengli@...cent.com>
Subject: [PATCH 12/29] xfs: enforce GFP_NOIO implicitly during nowait time update

From: Hao Xu <howeyxu@...cent.com>

Enforce GFP_NOIO logic implicitly by set pflags if we are in nowait
time update process. Nowait semantics means no waiting for IO,
therefore GFP_NOIO is needed.

Signed-off-by: Hao Xu <howeyxu@...cent.com>
---
 fs/xfs/xfs_iops.c | 22 +++++++++++++++++-----
 1 file changed, 17 insertions(+), 5 deletions(-)

diff --git a/fs/xfs/xfs_iops.c b/fs/xfs/xfs_iops.c
index bf1d4c31f009..5fa391083de9 100644
--- a/fs/xfs/xfs_iops.c
+++ b/fs/xfs/xfs_iops.c
@@ -1037,6 +1037,8 @@ xfs_vn_update_time(
 	int			log_flags = XFS_ILOG_TIMESTAMP;
 	struct xfs_trans	*tp;
 	int			error;
+	int			old_pflags;
+	bool			nowait = flags & S_NOWAIT;
 
 	trace_xfs_update_time(ip);
 
@@ -1049,13 +1051,18 @@ xfs_vn_update_time(
 		log_flags |= XFS_ILOG_CORE;
 	}
 
+	if (nowait)
+		old_pflags = memalloc_noio_save();
+
 	error = xfs_trans_alloc(mp, &M_RES(mp)->tr_fsyncts, 0, 0, 0, &tp);
 	if (error)
-		return error;
+		goto out;
 
-	if (flags & S_NOWAIT) {
-		if (!xfs_ilock_nowait(ip, XFS_ILOCK_EXCL))
-			return -EAGAIN;
+	if (nowait) {
+		if (!xfs_ilock_nowait(ip, XFS_ILOCK_EXCL)) {
+			error = -EAGAIN;
+			goto out;
+		}
 	} else {
 		xfs_ilock(ip, XFS_ILOCK_EXCL);
 	}
@@ -1069,7 +1076,12 @@ xfs_vn_update_time(
 
 	xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
 	xfs_trans_log_inode(tp, ip, log_flags);
-	return xfs_trans_commit(tp);
+	error = xfs_trans_commit(tp);
+
+out:
+	if (nowait)
+		memalloc_noio_restore(old_pflags);
+	return error;
 }
 
 STATIC int
-- 
2.25.1