linux-kernel - [PATCH 3/4] xfs: use IOCB_DONTCACHE when falling back to buffered writes

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 for Android: free password hash cracker in your pocket

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

Message-ID: <20251029071537.1127397-4-hch@lst.de>
Date: Wed, 29 Oct 2025 08:15:04 +0100
From: Christoph Hellwig <hch@....de>
To: Carlos Maiolino <cem@...nel.org>,
	Christian Brauner <brauner@...nel.org>
Cc: Jan Kara <jack@...e.cz>,
	"Martin K. Petersen" <martin.petersen@...cle.com>,
	linux-kernel@...r.kernel.org,
	linux-xfs@...r.kernel.org,
	linux-fsdevel@...r.kernel.org,
	linux-raid@...r.kernel.org,
	linux-block@...r.kernel.org
Subject: [PATCH 3/4] xfs: use IOCB_DONTCACHE when falling back to buffered writes

Doing sub-block direct writes to COW inodes is not supported by XFS,
because new blocks need to be allocated as a whole.  Such writes
fall back to buffered I/O, and really should be using the
IOCB_DONTCACHE that didn't exist when the code was added to mimic
direct I/O semantics as closely as possible.  Also clear the
IOCB_DIRECT flags so that later code can't get confused by it being
set for something that at this point is not a direct I/O operation
any more.

Signed-off-by: Christoph Hellwig <hch@....de>
---
 fs/xfs/xfs_file.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index 5703b6681b1d..e09ae86e118e 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -1119,6 +1119,9 @@ xfs_file_write_iter(
 		ret = xfs_file_dio_write(iocb, from);
 		if (ret != -ENOTBLK)
 			return ret;
+
+		iocb->ki_flags &= ~IOCB_DIRECT;
+		iocb->ki_flags |= IOCB_DONTCACHE;
 	}

 	if (xfs_is_zoned_inode(ip))
-- 
2.47.3