diff options
| -rw-r--r-- | drivers/block/loop.c | 75 |
1 files changed, 36 insertions, 39 deletions
diff --git a/drivers/block/loop.c b/drivers/block/loop.c index 86b5d956dc4e..cbda971d22b4 100644 --- a/drivers/block/loop.c +++ b/drivers/block/loop.c @@ -1123,20 +1123,12 @@ out_putf: return error; } -static void __loop_clr_fd(struct loop_device *lo, bool release) +static void __loop_clr_fd(struct loop_device *lo) { struct queue_limits lim; struct file *filp; gfp_t gfp = lo->old_gfp_mask; - /* - * Freeze the request queue when unbinding on a live file descriptor and - * thus an open device. When called from ->release we are guaranteed - * that there is no I/O in progress already. - */ - if (!release) - blk_mq_freeze_queue(lo->lo_queue); - spin_lock_irq(&lo->lo_lock); filp = lo->lo_backing_file; lo->lo_backing_file = NULL; @@ -1161,8 +1153,6 @@ static void __loop_clr_fd(struct loop_device *lo, bool release) mapping_set_gfp_mask(filp->f_mapping, gfp); /* This is safe: open() is still holding a reference. */ module_put(THIS_MODULE); - if (!release) - blk_mq_unfreeze_queue(lo->lo_queue); disk_force_media_change(lo->lo_disk); @@ -1177,11 +1167,7 @@ static void __loop_clr_fd(struct loop_device *lo, bool release) * must be at least one and it can only become zero when the * current holder is released. */ - if (!release) - mutex_lock(&lo->lo_disk->open_mutex); err = bdev_disk_changed(lo->lo_disk, false); - if (!release) - mutex_unlock(&lo->lo_disk->open_mutex); if (err) pr_warn("%s: partition scan of loop%d failed (rc=%d)\n", __func__, lo->lo_number, err); @@ -1230,24 +1216,16 @@ static int loop_clr_fd(struct loop_device *lo) return -ENXIO; } /* - * If we've explicitly asked to tear down the loop device, - * and it has an elevated reference count, set it for auto-teardown when - * the last reference goes away. This stops $!~#$@ udev from - * preventing teardown because it decided that it needs to run blkid on - * the loopback device whenever they appear. xfstests is notorious for - * failing tests because blkid via udev races with a losetup - * <dev>/do something like mkfs/losetup -d <dev> causing the losetup -d - * command to fail with EBUSY. + * Mark the device for removing the backing device on last close. + * If we are the only opener, also switch the state to roundown here to + * prevent new openers from coming in. */ - if (disk_openers(lo->lo_disk) > 1) { - lo->lo_flags |= LO_FLAGS_AUTOCLEAR; - loop_global_unlock(lo, true); - return 0; - } - lo->lo_state = Lo_rundown; + + lo->lo_flags |= LO_FLAGS_AUTOCLEAR; + if (disk_openers(lo->lo_disk) == 1) + lo->lo_state = Lo_rundown; loop_global_unlock(lo, true); - __loop_clr_fd(lo, false); return 0; } @@ -1714,25 +1692,43 @@ static int lo_compat_ioctl(struct block_device *bdev, blk_mode_t mode, } #endif +static int lo_open(struct gendisk *disk, blk_mode_t mode) +{ + struct loop_device *lo = disk->private_data; + int err; + + err = mutex_lock_killable(&lo->lo_mutex); + if (err) + return err; + + if (lo->lo_state == Lo_deleting || lo->lo_state == Lo_rundown) + err = -ENXIO; + mutex_unlock(&lo->lo_mutex); + return err; +} + static void lo_release(struct gendisk *disk) { struct loop_device *lo = disk->private_data; + bool need_clear = false; if (disk_openers(disk) > 0) return; + /* + * Clear the backing device information if this is the last close of + * a device that's been marked for auto clear, or on which LOOP_CLR_FD + * has been called. + */ mutex_lock(&lo->lo_mutex); - if (lo->lo_state == Lo_bound && (lo->lo_flags & LO_FLAGS_AUTOCLEAR)) { + if (lo->lo_state == Lo_bound && (lo->lo_flags & LO_FLAGS_AUTOCLEAR)) lo->lo_state = Lo_rundown; - mutex_unlock(&lo->lo_mutex); - /* - * In autoclear mode, stop the loop thread - * and remove configuration after last close. - */ - __loop_clr_fd(lo, true); - return; - } + + need_clear = (lo->lo_state == Lo_rundown); mutex_unlock(&lo->lo_mutex); + + if (need_clear) + __loop_clr_fd(lo); } static void lo_free_disk(struct gendisk *disk) @@ -1749,6 +1745,7 @@ static void lo_free_disk(struct gendisk *disk) static const struct block_device_operations lo_fops = { .owner = THIS_MODULE, + .open = lo_open, .release = lo_release, .ioctl = lo_ioctl, #ifdef CONFIG_COMPAT |