UPSTREAM: loop: add ioctl for changing logical block size
This is a different approach from the first attempt in f2c6df7dbf9a
("loop: support 4k physical blocksize"). Rather than extending
LOOP_{GET,SET}_STATUS, add a separate ioctl just for setting the block
size.
Change-Id: I8d847f9f33263de9840c5e236a9f0fb7caf1edb4
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
(cherry picked from commit 89e4fdecb51cf5535867026274bc97de9480ade5)
Signed-off-by: Martijn Coenen <maco@android.com>
diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index 9f840d9..0c1df05 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -1059,6 +1059,7 @@ static int loop_clr_fd(struct loop_device *lo)
memset(lo->lo_encrypt_key, 0, LO_KEY_SIZE);
memset(lo->lo_crypt_name, 0, LO_NAME_SIZE);
memset(lo->lo_file_name, 0, LO_NAME_SIZE);
+ blk_queue_logical_block_size(lo->lo_queue, 512);
if (bdev) {
bdput(bdev);
invalidate_bdev(bdev);
@@ -1344,6 +1345,24 @@ static int loop_set_dio(struct loop_device *lo, unsigned long arg)
return error;
}
+static int loop_set_block_size(struct loop_device *lo, unsigned long arg)
+{
+ if (lo->lo_state != Lo_bound)
+ return -ENXIO;
+
+ if (arg < 512 || arg > PAGE_SIZE || !is_power_of_2(arg))
+ return -EINVAL;
+
+ blk_mq_freeze_queue(lo->lo_queue);
+
+ blk_queue_logical_block_size(lo->lo_queue, arg);
+ loop_update_dio(lo);
+
+ blk_mq_unfreeze_queue(lo->lo_queue);
+
+ return 0;
+}
+
static int lo_ioctl(struct block_device *bdev, fmode_t mode,
unsigned int cmd, unsigned long arg)
{
@@ -1392,6 +1411,11 @@ static int lo_ioctl(struct block_device *bdev, fmode_t mode,
if ((mode & FMODE_WRITE) || capable(CAP_SYS_ADMIN))
err = loop_set_dio(lo, arg);
break;
+ case LOOP_SET_BLOCK_SIZE:
+ err = -EPERM;
+ if ((mode & FMODE_WRITE) || capable(CAP_SYS_ADMIN))
+ err = loop_set_block_size(lo, arg);
+ break;
default:
err = lo->ioctl ? lo->ioctl(lo, cmd, arg) : -EINVAL;
}
diff --git a/include/uapi/linux/loop.h b/include/uapi/linux/loop.h
index c8125ec..23158db 100644
--- a/include/uapi/linux/loop.h
+++ b/include/uapi/linux/loop.h
@@ -88,6 +88,7 @@ struct loop_info64 {
#define LOOP_CHANGE_FD 0x4C06
#define LOOP_SET_CAPACITY 0x4C07
#define LOOP_SET_DIRECT_IO 0x4C08
+#define LOOP_SET_BLOCK_SIZE 0x4C09
/* /dev/loop-control interface */
#define LOOP_CTL_ADD 0x4C80