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From:   Hao Xu <hao.xu@linux.dev>
To:     io-uring@vger.kernel.org, Jens Axboe <axboe@kernel.dk>
Cc:     Dominique Martinet <asmadeus@codewreck.org>,
        Pavel Begunkov <asml.silence@gmail.com>,
        Christian Brauner <brauner@kernel.org>,
        Alexander Viro <viro@zeniv.linux.org.uk>,
        Stefan Roesch <shr@fb.com>, Clay Harris <bugs@claycon.org>,
        Dave Chinner <david@fromorbit.com>,
        "Darrick J . Wong" <djwong@kernel.org>,
        linux-fsdevel@vger.kernel.org, linux-xfs@vger.kernel.org,
        linux-ext4@vger.kernel.org, Wanpeng Li <wanpengli@tencent.com>
Subject: [PATCH 2/7] xfs: add nowait support for xfs_seek_iomap_begin()
Date:   Wed, 26 Jul 2023 18:25:58 +0800
Message-Id: <20230726102603.155522-3-hao.xu@linux.dev>
In-Reply-To: <20230726102603.155522-1-hao.xu@linux.dev>
References: <20230726102603.155522-1-hao.xu@linux.dev>
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From: Hao Xu <howeyxu@tencent.com>

To support nowait llseek(), IOMAP_NOWAIT semantics should be respected.
In xfs, xfs_seek_iomap_begin() is the only place which may be blocked
by ilock and extent loading. Let's turn it into trylock logic just like
what we've done in xfs_readdir().

Signed-off-by: Hao Xu <howeyxu@tencent.com>
---
 fs/xfs/xfs_iomap.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c
index 18c8f168b153..bbd7c6b27701 100644
--- a/fs/xfs/xfs_iomap.c
+++ b/fs/xfs/xfs_iomap.c
@@ -1294,7 +1294,9 @@ xfs_seek_iomap_begin(
 	if (xfs_is_shutdown(mp))
 		return -EIO;
 
-	lockmode = xfs_ilock_data_map_shared(ip);
+	lockmode = xfs_ilock_data_map_shared_generic(ip, flags & IOMAP_NOWAIT);
+	if (!lockmode)
+		return -EAGAIN;
 	error = xfs_iread_extents(NULL, ip, XFS_DATA_FORK);
 	if (error)
 		goto out_unlock;
-- 
2.25.1