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authorChristoph Hellwig <hch@lst.de>2021-01-09 11:42:51 +0100
committerJens Axboe <axboe@kernel.dk>2021-01-24 18:15:57 -0700
commit52f019d43c229afd65dc11c8c1b05b6436bf6765 (patch)
tree6de92dfcc55365264daef7a0bbaaf2f96a39b8e0 /block/genhd.c
parent6f0d9689b670bc9f9640ff87b3f9226b7806dea2 (diff)
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block: add a hard-readonly flag to struct gendisk
Commit 20bd1d026aac ("scsi: sd: Keep disk read-only when re-reading partition") addressed a long-standing problem with user read-only policy being overridden as a result of a device-initiated revalidate. The commit has since been reverted due to a regression that left some USB devices read-only indefinitely. To fix the underlying problems with revalidate we need to keep track of hardware state and user policy separately. The gendisk has been updated to reflect the current hardware state set by the device driver. This is done to allow returning the device to the hardware state once the user clears the BLKROSET flag. The resulting semantics are as follows: - If BLKROSET sets a given partition read-only, that partition will remain read-only even if the underlying storage stack initiates a revalidate. However, the BLKRRPART ioctl will cause the partition table to be dropped and any user policy on partitions will be lost. - If BLKROSET has not been set, both the whole disk device and any partitions will reflect the current write-protect state of the underlying device. Based on a patch from Martin K. Petersen <martin.petersen@oracle.com>. Reported-by: Oleksii Kurochko <olkuroch@cisco.com> Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=201221 Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Reviewed-by: Hannes Reinecke <hare@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block/genhd.c')
-rw-r--r--block/genhd.c33
1 files changed, 19 insertions, 14 deletions
diff --git a/block/genhd.c b/block/genhd.c
index 484a474648d5..1873e4571328 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -1637,27 +1637,32 @@ static void set_disk_ro_uevent(struct gendisk *gd, int ro)
kobject_uevent_env(&disk_to_dev(gd)->kobj, KOBJ_CHANGE, envp);
}
-void set_disk_ro(struct gendisk *disk, int flag)
+/**
+ * set_disk_ro - set a gendisk read-only
+ * @disk: gendisk to operate on
+ * @ready_only: %true to set the disk read-only, %false set the disk read/write
+ *
+ * This function is used to indicate whether a given disk device should have its
+ * read-only flag set. set_disk_ro() is typically used by device drivers to
+ * indicate whether the underlying physical device is write-protected.
+ */
+void set_disk_ro(struct gendisk *disk, bool read_only)
{
- struct disk_part_iter piter;
- struct block_device *part;
-
- if (disk->part0->bd_read_only != flag) {
- set_disk_ro_uevent(disk, flag);
- disk->part0->bd_read_only = flag;
+ if (read_only) {
+ if (test_and_set_bit(GD_READ_ONLY, &disk->state))
+ return;
+ } else {
+ if (!test_and_clear_bit(GD_READ_ONLY, &disk->state))
+ return;
}
-
- disk_part_iter_init(&piter, disk, DISK_PITER_INCL_EMPTY);
- while ((part = disk_part_iter_next(&piter)))
- part->bd_read_only = flag;
- disk_part_iter_exit(&piter);
+ set_disk_ro_uevent(disk, read_only);
}
-
EXPORT_SYMBOL(set_disk_ro);
int bdev_read_only(struct block_device *bdev)
{
- return bdev->bd_read_only;
+ return bdev->bd_read_only ||
+ test_bit(GD_READ_ONLY, &bdev->bd_disk->state);
}
EXPORT_SYMBOL(bdev_read_only);