linux-kernel - [PATCH 11/11] xfs: enable non-blocking timestamp updates

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Message-ID: <20260106075008.1610195-12-hch@lst.de>
Date: Tue,  6 Jan 2026 08:50:05 +0100
From: Christoph Hellwig <hch@....de>
To: Christian Brauner <brauner@...nel.org>
Cc: Al Viro <viro@...iv.linux.org.uk>,
	David Sterba <dsterba@...e.com>,
	Jan Kara <jack@...e.cz>,
	Mike Marshall <hubcap@...ibond.com>,
	Martin Brandenburg <martin@...ibond.com>,
	Carlos Maiolino <cem@...nel.org>,
	Stefan Roesch <shr@...com>,
	Jeff Layton <jlayton@...nel.org>,
	OGAWA Hirofumi <hirofumi@...l.parknet.co.jp>,
	Trond Myklebust <trondmy@...nel.org>,
	Anna Schumaker <anna@...nel.org>,
	linux-kernel@...r.kernel.org,
	linux-btrfs@...r.kernel.org,
	linux-fsdevel@...r.kernel.org,
	gfs2@...ts.linux.dev,
	io-uring@...r.kernel.org,
	devel@...ts.orangefs.org,
	linux-unionfs@...r.kernel.org,
	linux-mtd@...ts.infradead.org,
	linux-xfs@...r.kernel.org,
	linux-nfs@...r.kernel.org,
	Chaitanya Kulkarni <kch@...dia.com>
Subject: [PATCH 11/11] xfs: enable non-blocking timestamp updates

The lazytime path using the generic helpers can never block in XFS
because there is no ->dirty_inode method that could block.  Allow
non-blocking timestamp updates for this case by replacing
generic_update_time with the open coded version without the S_NOWAIT
check.

Fixes: 66fa3cedf16a ("fs: Add async write file modification handling.")
Signed-off-by: Christoph Hellwig <hch@....de>
Reviewed-by: Chaitanya Kulkarni <kch@...dia.com>
Reviewed-by: Jeff Layton <jlayton@...nel.org>
---
 fs/xfs/xfs_iops.c | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

diff --git a/fs/xfs/xfs_iops.c b/fs/xfs/xfs_iops.c
index 338f3113f674..1cdd8a360510 100644
--- a/fs/xfs/xfs_iops.c
+++ b/fs/xfs/xfs_iops.c
@@ -1195,16 +1195,22 @@ xfs_vn_update_time(
 
 	trace_xfs_update_time(ip);
 
-	if (flags & IOCB_NOWAIT)
-		return -EAGAIN;
-
 	if (inode->i_sb->s_flags & SB_LAZYTIME) {
-		if (type == FS_UPD_ATIME ||
-		    !inode_maybe_inc_iversion(inode, false))
-			return generic_update_time(inode, type, flags);
+		int dirty;
+
+		dirty = inode_update_time(inode, type, flags);
+		if (dirty <= 0)
+			return dirty;
+		if (dirty == I_DIRTY_TIME) {
+			__mark_inode_dirty(inode, I_DIRTY_TIME);
+			return 0;
+		}
 
 		/* Capture the iversion update that just occurred */
 		log_flags |= XFS_ILOG_CORE;
+	} else {
+		if (flags & IOCB_NOWAIT)
+			return -EAGAIN;
 	}
 
 	error = xfs_trans_alloc(mp, &M_RES(mp)->tr_fsyncts, 0, 0, 0, &tp);
-- 
2.47.3