linux-ext4 - [PATCH 06/10] mm,btrfs: add a filemap_fdatawrite_kick

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: <20251013025808.4111128-7-hch@lst.de>
Date: Mon, 13 Oct 2025 11:58:01 +0900
From: Christoph Hellwig <hch@....de>
To: "Matthew Wilcox (Oracle)" <willy@...radead.org>,
	Eric Van Hensbergen <ericvh@...nel.org>,
	Latchesar Ionkov <lucho@...kov.net>,
	Dominique Martinet <asmadeus@...ewreck.org>,
	Christian Schoenebeck <linux_oss@...debyte.com>,
	Chris Mason <clm@...com>,
	David Sterba <dsterba@...e.com>,
	Mark Fasheh <mark@...heh.com>,
	Joel Becker <jlbec@...lplan.org>,
	Joseph Qi <joseph.qi@...ux.alibaba.com>
Cc: Alexander Viro <viro@...iv.linux.org.uk>,
	Christian Brauner <brauner@...nel.org>,
	Josef Bacik <josef@...icpanda.com>,
	Jan Kara <jack@...e.cz>,
	linux-block@...r.kernel.org,
	v9fs@...ts.linux.dev,
	linux-btrfs@...r.kernel.org,
	linux-ext4@...r.kernel.org,
	linux-fsdevel@...r.kernel.org,
	jfs-discussion@...ts.sourceforge.net,
	ocfs2-devel@...ts.linux.dev,
	linux-xfs@...r.kernel.org,
	linux-mm@...ck.org
Subject: [PATCH 06/10] mm,btrfs: add a filemap_fdatawrite_kick_nr helper

Abstract out the btrfs-specific behavior of kicking off I/O on a number
of pages on an address_space into a well-defined helper.

Signed-off-by: Christoph Hellwig <hch@....de>
---
 fs/btrfs/inode.c        | 13 ++-----------
 include/linux/pagemap.h |  2 ++
 mm/filemap.c            | 22 ++++++++++++++++++++++
 3 files changed, 26 insertions(+), 11 deletions(-)

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index b97d6c1f7772..b63d77154c45 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -8752,19 +8752,10 @@ static int start_delalloc_inodes(struct btrfs_root *root, long *nr_to_write,
 			btrfs_queue_work(root->fs_info->flush_workers,
 					 &work->work);
 		} else {
-			struct writeback_control wbc = {
-				.nr_to_write = *nr_to_write,
-				.sync_mode = WB_SYNC_NONE,
-				.range_start = 0,
-				.range_end = LLONG_MAX,
-			};
-
-			ret = filemap_fdatawrite_wbc(tmp_inode->i_mapping,
-					&wbc);
+			ret = filemap_fdatawrite_kick_nr(tmp_inode->i_mapping,
+					nr_to_write);
 			btrfs_add_delayed_iput(inode);
 
-			if (*nr_to_write != LONG_MAX)
-				*nr_to_write = wbc.nr_to_write;
 			if (ret || *nr_to_write <= 0)
 				goto out;
 		}
diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index 09b581c1d878..fc060ce2d31d 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -38,6 +38,8 @@ int filemap_invalidate_pages(struct address_space *mapping,
 int write_inode_now(struct inode *, int sync);
 int filemap_fdatawrite(struct address_space *);
 int filemap_flush(struct address_space *);
+int filemap_fdatawrite_kick_nr(struct address_space *mapping,
+		long *nr_to_write);
 int filemap_fdatawait_keep_errors(struct address_space *mapping);
 int filemap_fdatawait_range(struct address_space *, loff_t lstart, loff_t lend);
 int filemap_fdatawait_range_keep_errors(struct address_space *mapping,
diff --git a/mm/filemap.c b/mm/filemap.c
index 99d6919af60d..b95e71774131 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -474,6 +474,28 @@ int filemap_flush(struct address_space *mapping)
 }
 EXPORT_SYMBOL(filemap_flush);
 
+/*
+ * Start writeback on @nr_to_write pages from @mapping.  No one but the existing
+ * btrfs caller should be using this.  Talk to linux-mm if you think adding a
+ * new caller is a good idea.
+ */
+int filemap_fdatawrite_kick_nr(struct address_space *mapping, long *nr_to_write)
+{
+	struct writeback_control wbc = {
+		.nr_to_write = *nr_to_write,
+		.sync_mode = WB_SYNC_NONE,
+		.range_start = 0,
+		.range_end = LLONG_MAX,
+	};
+	int ret;
+
+	ret = filemap_fdatawrite_wbc(mapping, &wbc);
+	if (!ret)
+		*nr_to_write = wbc.nr_to_write;
+	return ret;
+}
+EXPORT_SYMBOL_FOR_MODULES(filemap_fdatawrite_kick_nr, "btrfs");
+
 /**
  * filemap_range_has_page - check if a page exists in range.
  * @mapping:           address space within which to check
-- 
2.47.3