Regular block device writes go through blkdev_write_iter(), which does
bdev_read_only(), while zeroout/discard/etc requests are never checked,
both userspace- and kernel-triggered. Add a generic catch-all check to
generic_make_request_checks() to actually enforce ioctl(BLKROSET) and
set_disk_ro(), which is used by quite a few drivers for things like
snapshots, read-only backing files/images, etc.
Signed-off-by: Ilya Dryomov <idryomov@xxxxxxxxx>
---
block/blk-core.c | 23 ++++++++++++++++++++++-
1 file changed, 22 insertions(+), 1 deletion(-)
diff --git a/block/blk-core.c b/block/blk-core.c
index b8d1aa2d1008..139ff47caf4a 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -2022,6 +2022,20 @@ static inline int bio_check_eod(struct bio *bio, unsigned int nr_sectors)
return 0;
}
+static inline bool bio_check_ro(struct bio *bio)
+{
+ struct hd_struct *p;
+ int ret = false;
+
+ rcu_read_lock();
+ p = __disk_get_part(bio->bi_disk, bio->bi_partno);
+ if (!p || (p->policy && op_is_write(bio_op(bio))))
+ ret = true;
+ rcu_read_unlock();
+
+ return ret;
+}
+
static noinline_for_stack bool
generic_make_request_checks(struct bio *bio)
{
@@ -2044,11 +2058,18 @@ generic_make_request_checks(struct bio *bio)
goto end_io;
}
+ if (bio_check_ro(bio)) {
+ printk(KERN_ERR
+ "generic_make_request: Trying to write "
+ "to read-only block-device %s (partno %d)\n",
+ bio_devname(bio, b), bio->bi_partno);
+ goto end_io;
+ }
+
/*
* For a REQ_NOWAIT based request, return -EOPNOTSUPP
* if queue is not a request based queue.
*/
-
if ((bio->bi_opf & REQ_NOWAIT) && !queue_is_rq_based(q))
goto not_supported;
--
2.4.3
