On 6/11/24 2:19 PM, Christoph Hellwig wrote:
> The LOOP_CONFIGURE path automatically upgrades the block size to that
> of the underlying file for O_DIRECT file descriptors, but the
> LOOP_SET_BLOCK_SIZE path does not. Fix this by lifting the code to
> pick the block size into common code.
s/lock/block in the commit title.
>
> Signed-off-by: Christoph Hellwig <hch@xxxxxx>
> ---
> drivers/block/loop.c | 25 +++++++++++++++----------
> 1 file changed, 15 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/block/loop.c b/drivers/block/loop.c
> index c658282454af1b..4f6d8514d19bd6 100644
> --- a/drivers/block/loop.c
> +++ b/drivers/block/loop.c
> @@ -975,10 +975,24 @@ loop_set_status_from_info(struct loop_device *lo,
> return 0;
> }
>
> +static unsigned short loop_default_blocksize(struct loop_device *lo,
> + struct block_device *backing_bdev)
> +{
> + /* In case of direct I/O, match underlying block size */
> + if ((lo->lo_backing_file->f_flags & O_DIRECT) && backing_bdev)
> + return bdev_logical_block_size(backing_bdev);
> + return 512;
Nit: SECTOR_SIZE ?
> +}
> +
> static int loop_reconfigure_limits(struct loop_device *lo, unsigned short bsize)
> {
> + struct file *file = lo->lo_backing_file;
> + struct inode *inode = file->f_mapping->host;
> struct queue_limits lim;
>
> + if (!bsize)
> + bsize = loop_default_blocksize(lo, inode->i_sb->s_bdev);
If bsize is specified and there is a backing dev used with direct IO, should it
be checked that bsize is a multiple of bdev_logical_block_size(backing_bdev) ?
> +
> lim = queue_limits_start_update(lo->lo_queue);
> lim.logical_block_size = bsize;
> lim.physical_block_size = bsize;
> @@ -997,7 +1011,6 @@ static int loop_configure(struct loop_device *lo, blk_mode_t mode,
> int error;
> loff_t size;
> bool partscan;
> - unsigned short bsize;
> bool is_loop;
>
> if (!file)
> @@ -1076,15 +1089,7 @@ static int loop_configure(struct loop_device *lo, blk_mode_t mode,
> if (!(lo->lo_flags & LO_FLAGS_READ_ONLY) && file->f_op->fsync)
> blk_queue_write_cache(lo->lo_queue, true, false);
>
> - if (config->block_size)
> - bsize = config->block_size;
> - else if ((lo->lo_backing_file->f_flags & O_DIRECT) && inode->i_sb->s_bdev)
> - /* In case of direct I/O, match underlying block size */
> - bsize = bdev_logical_block_size(inode->i_sb->s_bdev);
> - else
> - bsize = 512;
> -
> - error = loop_reconfigure_limits(lo, bsize);
> + error = loop_reconfigure_limits(lo, config->block_size);
> if (WARN_ON_ONCE(error))
> goto out_unlock;
>
--
Damien Le Moal
Western Digital Research
