From: Omar Sandoval <[email protected]> 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.
Signed-off-by: Omar Sandoval <[email protected]> --- drivers/block/loop.c | 24 ++++++++++++++++++++++++ include/uapi/linux/loop.h | 1 + 2 files changed, 25 insertions(+) diff --git a/drivers/block/loop.c b/drivers/block/loop.c index 1a5b4ecf54ec..6b1d932028e3 100644 --- a/drivers/block/loop.c +++ b/drivers/block/loop.c @@ -1047,6 +1047,7 @@ 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); @@ -1330,6 +1331,24 @@ 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) { @@ -1378,6 +1397,11 @@ 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 c8125ec1f4f2..23158dbe2424 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 -- 2.14.1
