On Mon, Mar 18, 2024 at 09:26:48AM +0800, Yu Kuai wrote: > Because there is a real filesystem(devtmpfs) used for raw block devcie > file operations, open syscall to devtmpfs: > > blkdev_open > bdev = blkdev_get_no_open > bdev_open -> pass in file is from devtmpfs > -> in this case, file inode is from devtmpfs, But file->f_mapping->host should still point to the bdevfs inode, and file->f_mapping->host is what everything in the I/O path should be using. > Then later, in blkdev_iomap_begin(), bd_inode is passed in and there is > no access to the devtmpfs file, we can't use s_bdev_file() as other > filesystems here. We can just pass the file down in iomap_iter.private
