Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
From:   John Garry <john.g.garry@oracle.com>
To:     axboe@kernel.dk, kbusch@kernel.org, hch@lst.de, sagi@grimberg.me,
        martin.petersen@oracle.com, djwong@kernel.org,
        viro@zeniv.linux.org.uk, brauner@kernel.org, dchinner@redhat.com,
        jejb@linux.ibm.com
Cc:     linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-nvme@lists.infradead.org, linux-scsi@vger.kernel.org,
        linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org,
        linux-security-module@vger.kernel.org, paul@paul-moore.com,
        jmorris@namei.org, serge@hallyn.com,
        Prasad Singamsetty <prasad.singamsetty@oracle.com>,
        John Garry <john.g.garry@oracle.com>
Subject: [PATCH RFC 02/16] fs/bdev: Add atomic write support info to statx
Date:   Wed,  3 May 2023 18:38:07 +0000
Message-Id: <20230503183821.1473305-3-john.g.garry@oracle.com>
In-Reply-To: <20230503183821.1473305-1-john.g.garry@oracle.com>
References: <20230503183821.1473305-1-john.g.garry@oracle.com>
Content-Transfer-Encoding: 8bit
Content-Type: text/plain
MIME-Version: 1.0
X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1
X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?HLG/h6KPI1pLESz+5cI0+OYXCfyccvVceYBeVGAyTMa6pIxMy+drR8pDGNlz?=
 =?us-ascii?Q?YVM1+iyK3LbH1N7hfCHoaDmN4USmDyirO/qGAgPJQlPsNeeVbGUBZ2let23o?=
 =?us-ascii?Q?8EHM288Zw07G42OWZ6ZIUYen8bio/BzLbblp4xnFPNEoEs9HRMDlJEovBRN1?=
 =?us-ascii?Q?JtevsoB7LHBJ0w9q40IegUPXVH33qqMRfjzAZO6mls39SV73HiVON5dOmgb7?=
 =?us-ascii?Q?tAboZeJeIFv5z4sXC9ya1xE+c6VwsP5+8Ba6ccCYWRYrDve59MAAkgJzYRQZ?=
 =?us-ascii?Q?EQVttllRHxJyBksciIxeM7RReYvwndxaIxZGVslWBZdIRME+rmFzTdI+KTP0?=
 =?us-ascii?Q?FLHNSzG+X3pDXXWY9AqCya8JAvFBTfEMIdMd4EeoGhnocsbO+I21cTHmUNEj?=
 =?us-ascii?Q?dFXS3nbHSwUhFvMi9RKPAFMEbOKA/GUjvJ1jbyfNuuvHrk9jhEUw7i/9KYtl?=
 =?us-ascii?Q?tfQTWtqvqgNBIaA0CvOZ6QO+kdrt3ceS6g/dgev/Q38RXxPQe2TLlTRYotRY?=
 =?us-ascii?Q?Rr1sF7nR4cOqCNSvBxqh2UncSIlIf6QMJBnEq1pe2BVZMyteTBpeMCxsquWH?=
 =?us-ascii?Q?DkOLv9AbSiX6CcnXQmNZmrR+Z0Vah1QR7k8XwshsAbvYImTO7q45QKCDBN9Y?=
 =?us-ascii?Q?BDvHaQNkQmjxuaj0Hc/LIzjfFBy+rMZn4Ic9U7bWw2jGt2UDkLg++1BMCfga?=
 =?us-ascii?Q?eAUZLLikZO7fqT4rNNczlRplNBrPkwY7sIugI4NwL0wBVB+xCgDOET0mDKwI?=
 =?us-ascii?Q?bmy2Z24IEVQU/cp1JXRua3hc9FAjMhfhSwdEho1b4MKYtBZgJaeA+b5XkfKY?=
 =?us-ascii?Q?4RIne/7lvaSDOI9kJofwxJiWNfiOd1WgfvDZJVMnApKOIjTouCeIRlRsZCHL?=
 =?us-ascii?Q?OktUd5wRBcqPt55AYAmaR64zgmMr/jz9ithoU/wgyMgumkQxXtZzp3/WxOrx?=
 =?us-ascii?Q?AdQGg183XEy26VdQVQ4tosG1IRJkbWgYP78q0sSird+0jyBgaRk0XHPotwqe?=
 =?us-ascii?Q?fec06L6LVcLZf1i5lMH4qyZ54Ko79sdNfKuLzxsk1wAazcsGYqVisaAkWrPu?=
 =?us-ascii?Q?cxooHob8yjgnUSUrNPuSMl77S3sfZR+MQQSUD+nDCbKYM5BgRMSTJ3lD/7Zy?=
 =?us-ascii?Q?A0Y0+ZvY/tjUi+AGCxqvsy/xM7RblDOZ5uzQYuAEAxHFEHdmw0JFN1k1bWmH?=
 =?us-ascii?Q?eBsvuGPIWzzZGeZ84UHeP6RA0WqzrzSrLrIK8Dy8XCG1ZEgmeMQB2wS5FNpz?=
 =?us-ascii?Q?BJyWfWWt4pLD82l/Wdgyik4ozmJexCQTX/GGRrI083eh58c4wO8GT8RglMt3?=
 =?us-ascii?Q?3xcgeSJUbVlH1GA06fpy2FdS0A4FGLx7MuUlzB+G92JQoO+2Lk7wT4Ufsm7f?=
 =?us-ascii?Q?uxYDQuJl54r2Ac3HX5NRbGv60epq5a1OuZ09fPEOBb2t4pyLtXfVah77zF1T?=
 =?us-ascii?Q?ZE+NT01r54dYeqwsvDRABX5aM20a3L0mBRv5i1lIaDtiLPYm5UQhd/EKayAq?=
 =?us-ascii?Q?PHq67eTP6l3gxmOl7gPPqa/cC7jmgGWf50WNUXGC7c1cYDCsKzOf5VqWhwhB?=
 =?us-ascii?Q?4GzopSv4QIfmfUc0QupjTxjerZfSlFGptBWHa83aKbQxY/PpKcz2XARe3o31?=
 =?us-ascii?Q?tA=3D=3D?=
X-MS-Exchange-AntiSpam-ExternalHop-MessageData-ChunkCount: 1
X-MS-Exchange-AntiSpam-ExternalHop-MessageData-0: =?us-ascii?Q?Gvi0wPUixmJxTQMog9XfLftIWTE9NYO6cnsDAEV+8nHV1UfCeS8yK4IblhsO?=
 =?us-ascii?Q?J65Nc/uXSwqR9e52T/e4kD8EQrBlsxmnBKPMp2+Z/jaXHQK5LFASslO+nRAk?=
 =?us-ascii?Q?EZS5syQH/5MWZmTLk78GrqRr24SGvVLOw5V6VKxOy1POxDaWA0UYHwNln2D5?=
 =?us-ascii?Q?3/b+Ft46H/HNYk/Kqjhj1CgwjS0UWTVpqGGyWlyIS+iCXvwV0gVHEb4KANoJ?=
 =?us-ascii?Q?x5qDritjI3sHNXKY5AcyonxrgOnEQovVnf/KVVO+HDLDy8bQ9YFb22++1M27?=
 =?us-ascii?Q?tv3a1VyudHpG5+SuPjzZMFmrQ+p/HxYEKR0suX22C21ctOqu2wJ//ouTj6Fx?=
 =?us-ascii?Q?K4vSPUdj9uT3l75sReL30hIFAOMp2FF/fydojtxJFKQRIsixPpFyLN5RS5uJ?=
 =?us-ascii?Q?pVKYVANw8WEj78JviiwPyCu4W7/u5h70ZN0e3oODadPp146AHRfTgaMDKKWa?=
 =?us-ascii?Q?2kzBpDizdxjC3iIE3VkekkGv36S5oygsXvsLNtkEFi88MkH70wv9JZzxPOJ4?=
 =?us-ascii?Q?eTCkglImbU9z8SfZCGQcPLrGOM8RnWCzkWOzxYSNPfCR0e4SHLRX94q2KkeM?=
 =?us-ascii?Q?YTunzM7ZFo2ErSVUKqV6QshBRCIid/JnQKlxGXw72vvq5b/OvpA69r3nS8y4?=
 =?us-ascii?Q?tTo61zFcp+RmOabaSvWaPUvG++ZUasfYURtYANSB3fV/Lm7i0N8EAKfkjEW2?=
 =?us-ascii?Q?G/thFZrKeDJz+cRXLr3btzAIs+mIgrki9RHFsR+mO32lChaIZviTINa0Gzui?=
 =?us-ascii?Q?C06ZIWXakVGR59pMs7r1hFnt4LgLv0M7Ccdni/H5AJba0ssRabfb7NAc2c5A?=
 =?us-ascii?Q?MCwyPAchGxC3uQXLNqYq9Hh1xuzCpXSt8t5z8/DVoP+kAip3GAqmyus40mJ2?=
 =?us-ascii?Q?9KBOFpOiD8zbxv7qdLcDc3i2EsRmA6O1U1ifvHXDM4MLAboxz+UrJvVMR5dG?=
 =?us-ascii?Q?EdCm+lMPjW08c0wEicbU9QgOdqPP8rHR50LAX1CN9ZDDWT3JFqx4kQ9EL3u4?=
 =?us-ascii?Q?4ppNtmjxy5S86FcmfLXKz/ekAyBmIuW7GNRaWY6Ipc+y8nzsAvQzCtWz0MFq?=
 =?us-ascii?Q?73X0faRQYU7JTcvNQBUITfvr2OrAkLl7eRtj/ags9UKoCtxSs/KLpUTQiqbV?=
 =?us-ascii?Q?QrDwMhyCKCou?=
X-OriginatorOrg: oracle.com
X-MS-Exchange-CrossTenant-Network-Message-Id: 77e0a29a-5755-4916-9500-08db4c05bb90
X-MS-Exchange-CrossTenant-AuthSource: DM6PR10MB4313.namprd10.prod.outlook.com
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 03 May 2023 18:39:30.9917
 (UTC)
X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted
X-MS-Exchange-CrossTenant-Id: 4e2c6054-71cb-48f1-bd6c-3a9705aca71b
X-MS-Exchange-CrossTenant-MailboxType: HOSTED
X-MS-Exchange-CrossTenant-UserPrincipalName: 8SQ0UYKfpvth7JE8pX/l6Izk3Um5HwZ6cF0FP9hidA+aFYc08+iBf0OquNSDPqBWWFeZFmvVpdfbaOi6l/mPUg==
X-MS-Exchange-Transport-CrossTenantHeadersStamped: IA1PR10MB6171
X-Proofpoint-Virus-Version: vendor=baseguard
 engine=ICAP:2.0.254,Aquarius:18.0.942,Hydra:6.0.573,FMLib:17.11.170.22
 definitions=2023-05-03_13,2023-05-03_01,2023-02-09_01
X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 malwarescore=0 bulkscore=0 spamscore=0
 mlxlogscore=999 mlxscore=0 adultscore=0 phishscore=0 suspectscore=0
 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2303200000
 definitions=main-2305030160
X-Proofpoint-GUID: ni2Fet1Pq0gaFvSxaD5rQsQlvtFNb6Gi
X-Proofpoint-ORIG-GUID: ni2Fet1Pq0gaFvSxaD5rQsQlvtFNb6Gi
X-Spam-Status: No, score=-2.8 required=5.0 tests=BAYES_00,DKIM_SIGNED,
        DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_LOW,
        RCVD_IN_MSPIKE_H2,SPF_HELO_NONE,SPF_NONE,T_SCC_BODY_TEXT_LINE
        autolearn=ham autolearn_force=no version=3.4.6
X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on
        lindbergh.monkeyblade.net
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

From: Prasad Singamsetty <prasad.singamsetty@oracle.com>

Extend statx system call to return additional info for atomic write support
support if the specified file is a block device.

Add initial support for a block device.

Signed-off-by: Prasad Singamsetty <prasad.singamsetty@oracle.com>
Signed-off-by: John Garry <john.g.garry@oracle.com>
---
 block/bdev.c              | 21 +++++++++++++++++++++
 fs/stat.c                 | 10 ++++++++++
 include/linux/blkdev.h    |  4 ++++
 include/linux/stat.h      |  2 ++
 include/uapi/linux/stat.h |  7 ++++++-
 5 files changed, 43 insertions(+), 1 deletion(-)

diff --git a/block/bdev.c b/block/bdev.c
index 1795c7d4b99e..6a5fd5abaadc 100644
--- a/block/bdev.c
+++ b/block/bdev.c
@@ -1014,3 +1014,24 @@ void bdev_statx_dioalign(struct inode *inode, struct kstat *stat)
 
 	blkdev_put_no_open(bdev);
 }
+
+/*
+ * Handle statx for block devices to get properties of WRITE ATOMIC
+ * feature support.
+ */
+void bdev_statx_atomic(struct inode *inode, struct kstat *stat)
+{
+	struct block_device *bdev;
+
+	bdev = blkdev_get_no_open(inode->i_rdev);
+	if (!bdev)
+		return;
+
+	stat->atomic_write_unit_min = queue_atomic_write_unit_min(bdev->bd_queue);
+	stat->atomic_write_unit_max = queue_atomic_write_unit_max(bdev->bd_queue);
+	stat->attributes |= STATX_ATTR_WRITE_ATOMIC;
+	stat->attributes_mask |= STATX_ATTR_WRITE_ATOMIC;
+	stat->result_mask |= STATX_WRITE_ATOMIC;
+
+	blkdev_put_no_open(bdev);
+}
diff --git a/fs/stat.c b/fs/stat.c
index 7c238da22ef0..d20334a0e9ae 100644
--- a/fs/stat.c
+++ b/fs/stat.c
@@ -256,6 +256,14 @@ static int vfs_statx(int dfd, struct filename *filename, int flags,
 			bdev_statx_dioalign(inode, stat);
 	}
 
+	/* Handle STATX_WRITE_ATOMIC for block devices */
+	if (request_mask & STATX_WRITE_ATOMIC) {
+		struct inode *inode = d_backing_inode(path.dentry);
+
+		if (S_ISBLK(inode->i_mode))
+			bdev_statx_atomic(inode, stat);
+	}
+
 	path_put(&path);
 	if (retry_estale(error, lookup_flags)) {
 		lookup_flags |= LOOKUP_REVAL;
@@ -636,6 +644,8 @@ cp_statx(const struct kstat *stat, struct statx __user *buffer)
 	tmp.stx_mnt_id = stat->mnt_id;
 	tmp.stx_dio_mem_align = stat->dio_mem_align;
 	tmp.stx_dio_offset_align = stat->dio_offset_align;
+	tmp.stx_atomic_write_unit_min = stat->atomic_write_unit_min;
+	tmp.stx_atomic_write_unit_max = stat->atomic_write_unit_max;
 
 	return copy_to_user(buffer, &tmp, sizeof(tmp)) ? -EFAULT : 0;
 }
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 6b6f2992338c..19d33b2897b2 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -1527,6 +1527,7 @@ int sync_blockdev_range(struct block_device *bdev, loff_t lstart, loff_t lend);
 int sync_blockdev_nowait(struct block_device *bdev);
 void sync_bdevs(bool wait);
 void bdev_statx_dioalign(struct inode *inode, struct kstat *stat);
+void bdev_statx_atomic(struct inode *inode, struct kstat *stat);
 void printk_all_partitions(void);
 #else
 static inline void invalidate_bdev(struct block_device *bdev)
@@ -1546,6 +1547,9 @@ static inline void sync_bdevs(bool wait)
 static inline void bdev_statx_dioalign(struct inode *inode, struct kstat *stat)
 {
 }
+static inline void bdev_statx_atomic(struct inode *inode, struct kstat *stat)
+{
+}
 static inline void printk_all_partitions(void)
 {
 }
diff --git a/include/linux/stat.h b/include/linux/stat.h
index 52150570d37a..dfa69ecfaacf 100644
--- a/include/linux/stat.h
+++ b/include/linux/stat.h
@@ -53,6 +53,8 @@ struct kstat {
 	u32		dio_mem_align;
 	u32		dio_offset_align;
 	u64		change_cookie;
+	u32		atomic_write_unit_max;
+	u32		atomic_write_unit_min;
 };
 
 /* These definitions are internal to the kernel for now. Mainly used by nfsd. */
diff --git a/include/uapi/linux/stat.h b/include/uapi/linux/stat.h
index 7cab2c65d3d7..c99d7cac2aa6 100644
--- a/include/uapi/linux/stat.h
+++ b/include/uapi/linux/stat.h
@@ -127,7 +127,10 @@ struct statx {
 	__u32	stx_dio_mem_align;	/* Memory buffer alignment for direct I/O */
 	__u32	stx_dio_offset_align;	/* File offset alignment for direct I/O */
 	/* 0xa0 */
-	__u64	__spare3[12];	/* Spare space for future expansion */
+	__u32	stx_atomic_write_unit_max;
+	__u32	stx_atomic_write_unit_min;
+	/* 0xb0 */
+	__u64	__spare3[11];	/* Spare space for future expansion */
 	/* 0x100 */
 };
 
@@ -154,6 +157,7 @@ struct statx {
 #define STATX_BTIME		0x00000800U	/* Want/got stx_btime */
 #define STATX_MNT_ID		0x00001000U	/* Got stx_mnt_id */
 #define STATX_DIOALIGN		0x00002000U	/* Want/got direct I/O alignment info */
+#define STATX_WRITE_ATOMIC	0x00004000U	/* Want/got atomic_write_* fields */
 
 #define STATX__RESERVED		0x80000000U	/* Reserved for future struct statx expansion */
 
@@ -189,6 +193,7 @@ struct statx {
 #define STATX_ATTR_MOUNT_ROOT		0x00002000 /* Root of a mount */
 #define STATX_ATTR_VERITY		0x00100000 /* [I] Verity protected file */
 #define STATX_ATTR_DAX			0x00200000 /* File is currently in DAX state */
+#define STATX_ATTR_WRITE_ATOMIC		0x00400000 /* File supports atomic write operations */
 
 
 #endif /* _UAPI_LINUX_STAT_H */
-- 
2.31.1