From 85560117d00f5d528e928918b8f61cadcefff98b Mon Sep 17 00:00:00 2001 From: Martijn Coenen Date: Wed, 4 Sep 2019 21:49:01 +0200 Subject: [PATCH] loop: change queue block size to match when using DIO The loop driver assumes that if the passed in fd is opened with O_DIRECT, the caller wants to use direct I/O on the loop device. However, if the underlying block device has a different block size than the loop block queue, direct I/O can't be enabled. Instead of requiring userspace to manually change the blocksize and re-enable direct I/O, just change the queue block sizes to match, as well as the io_min size. Reviewed-by: Christoph Hellwig Signed-off-by: Martijn Coenen Signed-off-by: Jens Axboe --- drivers/block/loop.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/drivers/block/loop.c b/drivers/block/loop.c index 1410fa893653..f6f77eaa7217 100644 --- a/drivers/block/loop.c +++ b/drivers/block/loop.c @@ -994,6 +994,16 @@ static int loop_set_fd(struct loop_device *lo, fmode_t mode, if (!(lo_flags & LO_FLAGS_READ_ONLY) && file->f_op->fsync) blk_queue_write_cache(lo->lo_queue, true, false); + if (io_is_direct(lo->lo_backing_file) && inode->i_sb->s_bdev) { + /* In case of direct I/O, match underlying block size */ + unsigned short bsize = bdev_logical_block_size( + inode->i_sb->s_bdev); + + blk_queue_logical_block_size(lo->lo_queue, bsize); + blk_queue_physical_block_size(lo->lo_queue, bsize); + blk_queue_io_min(lo->lo_queue, bsize); + } + loop_update_rotational(lo); loop_update_dio(lo); set_capacity(lo->lo_disk, size); -- 2.25.1