linux-kernel - [PATCH v3 19/21] xfs: Support atomic write for statx

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date: Mon, 29 Apr 2024 17:47:44 +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 19/21] xfs: Support atomic write for statx

Support providing info on atomic write unit min and max for an inode.

For simplicity, currently we limit the min at the FS block size, but a
lower limit could be supported in future. This is required by iomap
DIO.

The atomic write unit min and max is limited by the guaranteed extent
alignment for the inode.

Signed-off-by: John Garry <john.g.garry@...cle.com>
---
 fs/xfs/xfs_iops.c | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/fs/xfs/xfs_iops.c b/fs/xfs/xfs_iops.c
index 66f8c47642e8..7d2ef3059ca5 100644
--- a/fs/xfs/xfs_iops.c
+++ b/fs/xfs/xfs_iops.c
@@ -546,6 +546,27 @@ xfs_stat_blksize(
 	return PAGE_SIZE;
 }
 
+static void
+xfs_get_atomic_write_attr(
+	struct xfs_inode	*ip,
+	unsigned int		*unit_min,
+	unsigned int		*unit_max)
+{
+	struct xfs_buftarg	*target = xfs_inode_buftarg(ip);
+	struct xfs_mount	*mp = ip->i_mount;
+	struct xfs_sb		*sbp = &mp->m_sb;
+	unsigned int		extsz_bytes = XFS_FSB_TO_B(mp, ip->i_extsize);
+
+	if (!xfs_inode_has_atomicwrites(ip)) {
+		*unit_min = 0;
+		*unit_max = 0;
+		return;
+	}
+
+	*unit_min = sbp->sb_blocksize;
+	*unit_max = min(target->bt_bdev_awu_max, extsz_bytes);
+}
+
 STATIC int
 xfs_vn_getattr(
 	struct mnt_idmap	*idmap,
@@ -619,6 +640,13 @@ xfs_vn_getattr(
 			stat->dio_mem_align = bdev_dma_alignment(bdev) + 1;
 			stat->dio_offset_align = bdev_logical_block_size(bdev);
 		}
+		if (request_mask & STATX_WRITE_ATOMIC) {
+			unsigned int unit_min, unit_max;
+
+			xfs_get_atomic_write_attr(ip, &unit_min, &unit_max);
+			generic_fill_statx_atomic_writes(stat,
+				unit_min, unit_max);
+		}
 		fallthrough;
 	default:
 		stat->blksize = xfs_stat_blksize(ip);
-- 
2.31.1