Commit b85930a0 authored by David Howells's avatar David Howells Committed by Jens Axboe
Browse files

splice: Make splice from a DAX file use copy_splice_read() 



Make a read splice from a DAX file go directly to copy_splice_read() to do
the reading as filemap_splice_read() is unlikely to find any pagecache to
splice.

I think this affects only erofs, Ext2, Ext4, fuse and XFS.

Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarChristian Brauner <brauner@kernel.org>
Reviewed-by: default avatarTheodore Ts'o <tytso@mit.edu>
Reviewed-by: default avatarGao Xiang <hsiangkao@linux.alibaba.com>
cc: Al Viro <viro@zeniv.linux.org.uk>
cc: Jens Axboe <axboe@kernel.dk>
cc: linux-erofs@lists.ozlabs.org
cc: linux-ext4@vger.kernel.org
cc: linux-xfs@vger.kernel.org
cc: linux-fsdevel@vger.kernel.org
cc: linux-block@vger.kernel.org
cc: linux-mm@kvack.org
Link: https://lore.kernel.org/r/20230522135018.2742245-9-dhowells@redhat.com


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent aa3dbde8

fs/splice.c

+3 −3
Original line number Diff line number Diff line
@@ -908,10 +908,10 @@ long vfs_splice_read(struct file *in, loff_t *ppos, 
	if (unlikely(!in->f_op->splice_read))

		return warn_unsupported(in, "read");

	/*

	 * O_DIRECT doesn't deal with the pagecache, so we allocate a buffer,

	 * copy into it and splice that into the pipe.

	 * O_DIRECT and DAX don't deal with the pagecache, so we allocate a

	 * buffer, copy into it and splice that into the pipe.

	 */

	if ((in->f_flags & O_DIRECT))

	if ((in->f_flags & O_DIRECT) || IS_DAX(in->f_mapping->host))

		return copy_splice_read(in, ppos, pipe, len, flags);

	return in->f_op->splice_read(in, ppos, pipe, len, flags);

}