linux-kernel - [PATCH v3 21/21] xfs: Support setting FMODE_CAN_ATOMIC

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Message-Id: <20240429174746.2132161-22-john.g.garry@oracle.com>
Date: Mon, 29 Apr 2024 17:47:46 +0000
From: John Garry <john.g.garry@...cle.com>
To: david@...morbit.com, djwong@...nel.org, hch@....de,
        viro@...iv.linux.org.uk, brauner@...nel.org, jack@...e.cz,
        chandan.babu@...cle.com, willy@...radead.org
Cc: axboe@...nel.dk, martin.petersen@...cle.com, linux-kernel@...r.kernel.org,
        linux-fsdevel@...r.kernel.org, tytso@....edu, jbongio@...gle.com,
        ojaswin@...ux.ibm.com, ritesh.list@...il.com, mcgrof@...nel.org,
        p.raghav@...sung.com, linux-xfs@...r.kernel.org,
        catherine.hoang@...cle.com, John Garry <john.g.garry@...cle.com>
Subject: [PATCH v3 21/21] xfs: Support setting FMODE_CAN_ATOMIC_WRITE

For when an inode is enabled for atomic writes, set FMODE_CAN_ATOMIC_WRITE
flag. Only direct IO is currently supported, so check for that also.

We rely on the block layer to reject atomic writes which exceed the bdev
request_queue limits, so don't bother checking any such thing here.

Signed-off-by: John Garry <john.g.garry@...cle.com>
---
 fs/xfs/xfs_file.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index 256d05c1be6a..5a17748eb6bd 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -1243,6 +1243,18 @@ xfs_file_remap_range(
 	return remapped > 0 ? remapped : ret;
 }
 
+static bool xfs_file_open_can_atomicwrite(
+	struct inode		*inode,
+	struct file		*file)
+{
+	struct xfs_inode	*ip = XFS_I(inode);
+
+	if (!(file->f_flags & O_DIRECT))
+		return false;
+
+	return xfs_inode_has_atomicwrites(ip);
+}
+
 STATIC int
 xfs_file_open(
 	struct inode	*inode,
@@ -1252,6 +1264,8 @@ xfs_file_open(
 		return -EIO;
 	file->f_mode |= FMODE_NOWAIT | FMODE_BUF_RASYNC | FMODE_BUF_WASYNC |
 			FMODE_DIO_PARALLEL_WRITE | FMODE_CAN_ODIRECT;
+	if (xfs_file_open_can_atomicwrite(inode, file))
+		file->f_mode |= FMODE_CAN_ATOMIC_WRITE;
 	return generic_file_open(inode, file);
 }
 
-- 
2.31.1