From b85930a07738a95047a51dc5bc06b18fd91a9799 Mon Sep 17 00:00:00 2001 From: David Howells <dhowells@redhat.com> Date: Mon, 22 May 2023 14:49:55 +0100 Subject: [PATCH] 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: David Howells <dhowells@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Christian Brauner <brauner@kernel.org> Reviewed-by: Theodore Ts'o <tytso@mit.edu> Reviewed-by: Gao 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: Jens Axboe <axboe@kernel.dk> --- fs/splice.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/fs/splice.c b/fs/splice.c index 76126b1aafcb..8268248df3a9 100644 --- a/fs/splice.c +++ b/fs/splice.c @@ -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); } -- 2.30.9