> +/* Copy source offset from source block device to destination block > + * device. Returns the length of bytes copied. > + */ > +ssize_t blkdev_copy_offload_failfast( > + struct block_device *bdev_in, loff_t pos_in, > + struct block_device *bdev_out, loff_t pos_out, > + size_t len, gfp_t gfp_mask) This is an odd and very misnamed interface. Either we have a klkdev_copy() interface that automatically falls back to a fallback (maybe with an opt-out), or we have separate blkdev_copy_offload/blkdev_copy_emulated interface and let the caller decide. But none of that really is "failfast". Also this needs to go into the helpers patch and not a patch that is supposed to just wire copying up for block device node. > index b07de77ef126..d27148a2543f 100644 > --- a/fs/read_write.c > +++ b/fs/read_write.c > @@ -1447,7 +1447,8 @@ static int generic_copy_file_checks(struct file *file_in, loff_t pos_in, > return -EOVERFLOW; > > /* Shorten the copy to EOF */ > - size_in = i_size_read(inode_in); > + size_in = i_size_read(file_in->f_mapping->host); generic_copy_file_checks needs to be fixed to use ->mapping->host both or inode_in and inode_out at the top of the file instead of this band aid. And that needs to be a separate patch with a Fixes tag. > @@ -1708,7 +1709,9 @@ int generic_file_rw_checks(struct file *file_in, struct file *file_out) > /* Don't copy dirs, pipes, sockets... */ > if (S_ISDIR(inode_in->i_mode) || S_ISDIR(inode_out->i_mode)) > return -EISDIR; > - if (!S_ISREG(inode_in->i_mode) || !S_ISREG(inode_out->i_mode)) > + > + if ((!S_ISREG(inode_in->i_mode) || !S_ISREG(inode_out->i_mode)) && > + (!S_ISBLK(inode_in->i_mode) || !S_ISBLK(inode_out->i_mode))) This is using weird indentation, and might also not be doing exactly what we want. I think the better thing to do here is to: 1) check for the accetable types only on the in inode 2) have a check that the mode matches for the in and out inodes And please do this as a separate prep patch instead of hiding it here.
