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[v9,05/19] fs: Propagate write hints to the struct block_device inode

Message ID 20240130214911.1863909-6-bvanassche@acm.org
State New
Headers show
Series Pass data lifetime information to SCSI disk devices | expand

Commit Message

Bart Van Assche Jan. 30, 2024, 9:48 p.m. UTC
Write hints applied with F_SET_RW_HINT on a block device affect the
block device inode only. Propagate these hints to the inode associated
with struct block_device because that is the inode used when writing
back dirty pages.

Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Jeff Layton <jlayton@kernel.org>
Cc: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
---
 fs/fcntl.c | 11 +++++++++++
 1 file changed, 11 insertions(+)
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Patch

diff --git a/fs/fcntl.c b/fs/fcntl.c
index fc73c5fae43c..cfb52c3a4577 100644
--- a/fs/fcntl.c
+++ b/fs/fcntl.c
@@ -319,6 +319,17 @@  static long fcntl_set_rw_hint(struct file *file, unsigned int cmd,
 	inode->i_write_hint = hint;
 	inode_unlock(inode);
 
+	/*
+	 * file->f_mapping->host may differ from inode. As an example,
+	 * blkdev_open() modifies file->f_mapping.
+	 */
+	if (file->f_mapping->host != inode) {
+		inode = file->f_mapping->host;
+		inode_lock(inode);
+		inode->i_write_hint = hint;
+		inode_unlock(inode);
+	}
+
 	return 0;
 }