linux-kernel - [RFC PATCH v4 10/11] block: add FALLOC_FL_WRITE

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]

Message-ID: <20250421021509.2366003-11-yi.zhang@huaweicloud.com>
Date: Mon, 21 Apr 2025 10:15:08 +0800
From: Zhang Yi <yi.zhang@...weicloud.com>
To: linux-fsdevel@...r.kernel.org,
	linux-ext4@...r.kernel.org,
	linux-block@...r.kernel.org,
	dm-devel@...ts.linux.dev,
	linux-nvme@...ts.infradead.org,
	linux-scsi@...r.kernel.org
Cc: linux-xfs@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	hch@....de,
	tytso@....edu,
	djwong@...nel.org,
	john.g.garry@...cle.com,
	bmarzins@...hat.com,
	chaitanyak@...dia.com,
	shinichiro.kawasaki@....com,
	brauner@...nel.org,
	yi.zhang@...wei.com,
	yi.zhang@...weicloud.com,
	chengzhihao1@...wei.com,
	yukuai3@...wei.com,
	yangerkun@...wei.com
Subject: [RFC PATCH v4 10/11] block: add FALLOC_FL_WRITE_ZEROES support

From: Zhang Yi <yi.zhang@...wei.com>

Add support for FALLOC_FL_WRITE_ZEROES. It directly calls
blkdev_issue_zeroout() with flags set to 0. The underlying process will
attempt to use the fastest method for issuing zeroes. First, the block
layer will try to issue a write zeroes command if the storage device
supports it; if not, it will fall back to issuing zeroed data. Then, the
storage device driver may attempt to submit an unmap write zero command
if the device supports it; if not, the driver may fall back to
submitting a no-unmap write zeroes command.

Signed-off-by: Zhang Yi <yi.zhang@...wei.com>
---
 block/fops.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/block/fops.c b/block/fops.c
index 77a5465309e7..e590c8997689 100644
--- a/block/fops.c
+++ b/block/fops.c
@@ -803,7 +803,7 @@ static ssize_t blkdev_read_iter(struct kiocb *iocb, struct iov_iter *to)
 
 #define	BLKDEV_FALLOC_FL_SUPPORTED					\
 		(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE |		\
-		 FALLOC_FL_ZERO_RANGE)
+		 FALLOC_FL_ZERO_RANGE | FALLOC_FL_WRITE_ZEROES)
 
 static long blkdev_fallocate(struct file *file, int mode, loff_t start,
 			     loff_t len)
@@ -847,6 +847,9 @@ static long blkdev_fallocate(struct file *file, int mode, loff_t start,
 	case FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE:
 		flags = BLKDEV_ZERO_NOFALLBACK;
 		break;
+	case FALLOC_FL_WRITE_ZEROES:
+		flags = 0;
+		break;
 	default:
 		error = -EOPNOTSUPP;
 		goto fail;
-- 
2.46.1