block: fail op_is_write() requests to read-only partitions
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.
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/block/blk-core.c b/block/blk-core.c
index 55f3380..c21a16e 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -2062,6 +2062,21 @@ static inline bool should_fail_request(struct hd_struct *part,
#endif /* CONFIG_FAIL_MAKE_REQUEST */
+static inline bool bio_check_ro(struct bio *bio, struct hd_struct *part)
+{
+ if (part->policy && op_is_write(bio_op(bio))) {
+ char b[BDEVNAME_SIZE];
+
+ printk(KERN_ERR
+ "generic_make_request: Trying to write "
+ "to read-only block-device %s (partno %d)\n",
+ bio_devname(bio, b), part->partno);
+ return true;
+ }
+
+ return false;
+}
+
/*
* Remap block n of partition p to block n+start(p) of the disk.
*/
@@ -2070,27 +2085,28 @@ static inline int blk_partition_remap(struct bio *bio)
struct hd_struct *p;
int ret = 0;
+ rcu_read_lock();
+ p = __disk_get_part(bio->bi_disk, bio->bi_partno);
+ if (unlikely(!p || should_fail_request(p, bio->bi_iter.bi_size) ||
+ bio_check_ro(bio, p))) {
+ ret = -EIO;
+ goto out;
+ }
+
/*
* Zone reset does not include bi_size so bio_sectors() is always 0.
* Include a test for the reset op code and perform the remap if needed.
*/
- if (!bio->bi_partno ||
- (!bio_sectors(bio) && bio_op(bio) != REQ_OP_ZONE_RESET))
- return 0;
+ if (!bio_sectors(bio) && bio_op(bio) != REQ_OP_ZONE_RESET)
+ goto out;
- rcu_read_lock();
- p = __disk_get_part(bio->bi_disk, bio->bi_partno);
- if (likely(p && !should_fail_request(p, bio->bi_iter.bi_size))) {
- bio->bi_iter.bi_sector += p->start_sect;
- bio->bi_partno = 0;
- trace_block_bio_remap(bio->bi_disk->queue, bio, part_devt(p),
- bio->bi_iter.bi_sector - p->start_sect);
- } else {
- printk("%s: fail for partition %d\n", __func__, bio->bi_partno);
- ret = -EIO;
- }
+ bio->bi_iter.bi_sector += p->start_sect;
+ bio->bi_partno = 0;
+ trace_block_bio_remap(bio->bi_disk->queue, bio, part_devt(p),
+ bio->bi_iter.bi_sector - p->start_sect);
+
+out:
rcu_read_unlock();
-
return ret;
}
@@ -2149,15 +2165,19 @@ generic_make_request_checks(struct bio *bio)
* 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;
if (should_fail_request(&bio->bi_disk->part0, bio->bi_iter.bi_size))
goto end_io;
- if (blk_partition_remap(bio))
- goto end_io;
+ if (!bio->bi_partno) {
+ if (unlikely(bio_check_ro(bio, &bio->bi_disk->part0)))
+ goto end_io;
+ } else {
+ if (blk_partition_remap(bio))
+ goto end_io;
+ }
if (bio_check_eod(bio, nr_sectors))
goto end_io;