This reverts commit ce8da5d13d8c ("loop: Avoid updating block size under exclusive owner") for the 6.6 kernel, because if the LTP ioctl_loop06 test is run with this patch in place, the test will fail, it leaves the host unable to kexec into the kernel again (hangs forever) and "losetup -a" will hang on attempting to access the /dev/loopN device that the test has set up.

The patch doesn't need to be reverted from 6.12, as it works fine there.

Cc: stable@vger.kernel.org # 6.6.x Signed-off-by: Eric Hagberg ehagberg@janestreet.com

---

--- b/drivers/block/loop.c +++ a/drivers/block/loop.c @@ -1472,36 +1472,19 @@ return error; }

+static int loop_set_block_size(struct loop_device *lo, unsigned long arg) -static int loop_set_block_size(struct loop_device *lo, blk_mode_t mode, - struct block_device *bdev, unsigned long arg) { int err = 0;

+ if (lo->lo_state != Lo_bound) + return -ENXIO; - /* - * If we don't hold exclusive handle for the device, upgrade to it - * here to avoid changing device under exclusive owner. - */ - if (!(mode & BLK_OPEN_EXCL)) { - err = bd_prepare_to_claim(bdev, loop_set_block_size, NULL); - if (err) - return err; - } - - err = mutex_lock_killable(&lo->lo_mutex); - if (err) - goto abort_claim; - - if (lo->lo_state != Lo_bound) { - err = -ENXIO; - goto unlock; - }

err = blk_validate_block_size(arg); if (err) return err;

if (lo->lo_queue->limits.logical_block_size == arg) + return 0; - goto unlock;

sync_blockdev(lo->lo_device); invalidate_bdev(lo->lo_device); @@ -1513,11 +1496,6 @@ loop_update_dio(lo); blk_mq_unfreeze_queue(lo->lo_queue);

-unlock: - mutex_unlock(&lo->lo_mutex); -abort_claim: - if (!(mode & BLK_OPEN_EXCL)) - bd_abort_claiming(bdev, loop_set_block_size); return err; }

@@ -1536,6 +1514,9 @@ case LOOP_SET_DIRECT_IO: err = loop_set_dio(lo, arg); break; + case LOOP_SET_BLOCK_SIZE: + err = loop_set_block_size(lo, arg); + break; default: err = -EINVAL; } @@ -1590,12 +1571,9 @@ break; case LOOP_GET_STATUS64: return loop_get_status64(lo, argp); - case LOOP_SET_BLOCK_SIZE: - if (!(mode & BLK_OPEN_WRITE) && !capable(CAP_SYS_ADMIN)) - return -EPERM; - return loop_set_block_size(lo, mode, bdev, arg); case LOOP_SET_CAPACITY: case LOOP_SET_DIRECT_IO: + case LOOP_SET_BLOCK_SIZE: if (!(mode & BLK_OPEN_WRITE) && !capable(CAP_SYS_ADMIN)) return -EPERM; fallthrough;