[PATCH v3 1/7] block: fail reads to offline zones early

[Damien Le Moal <dlemoal@kernel.org>]

Any BIO targeting an offline zone of a zoned block device will fail,
including read commands. So there is no point in issuing read BIOs.
Fail these read operations early if we ever see one.

Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
---
 block/blk-core.c  |  3 +++
 block/blk-zoned.c | 18 ++++++++++++++++++
 block/blk.h       |  6 ++++++
 3 files changed, 27 insertions(+)

diff --git a/block/blk-core.c b/block/blk-core.c
index 13dc70e8f55d..d420c80d2d93 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -866,6 +866,9 @@ void submit_bio_noacct(struct bio *bio)
 
 	switch (bio_op(bio)) {
 	case REQ_OP_READ:
+		if (bdev_is_zoned(bdev) &&
+		    bdev_zone_is_offline(bdev, bio->bi_iter.bi_sector))
+			goto end_io;
 		break;
 	case REQ_OP_WRITE:
 		if (bio->bi_opf & REQ_ATOMIC) {
diff --git a/block/blk-zoned.c b/block/blk-zoned.c
index 19268afb8752..131c9f50b3da 100644
--- a/block/blk-zoned.c
+++ b/block/blk-zoned.c
@@ -308,6 +308,24 @@ bool bdev_zone_is_seq(struct block_device *bdev, sector_t sector)
 }
 EXPORT_SYMBOL_GPL(bdev_zone_is_seq);
 
+/**
+ * bdev_zone_is_offline - check if a sector belongs to an offline zone
+ * @bdev:       block device to check
+ * @sector:     sector number
+ *
+ * Check if @sector on @bdev is contained in an offline zone.
+ */
+bool bdev_zone_is_offline(struct block_device *bdev, sector_t sector)
+{
+	enum blk_zone_cond cond;
+
+	if (!bdev_is_zoned(bdev))
+		return false;
+
+	cond = disk_zone_get_cond(bdev->bd_disk, sector);
+	return cond == BLK_ZONE_COND_OFFLINE;
+}
+
 /**
  * bdev_zone_mgmt_allowed - check if management operations are allowed on a zone
  * @bdev:       block device to check
diff --git a/block/blk.h b/block/blk.h
index 2cc03aa54c53..c2d07347a3ad 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -578,6 +578,7 @@ int blkdev_report_zones_ioctl(struct block_device *bdev, unsigned int cmd,
 int blkdev_zone_mgmt_ioctl(struct block_device *bdev, blk_mode_t mode,
 		unsigned int cmd, unsigned long arg);
 bool bdev_zone_mgmt_allowed(struct block_device *bdev, sector_t sector);
+bool bdev_zone_is_offline(struct block_device *bdev, sector_t sector);
 #else /* CONFIG_BLK_DEV_ZONED */
 static inline void disk_init_zone_resources(struct gendisk *disk)
 {
@@ -625,6 +626,11 @@ static inline bool bdev_zone_mgmt_allowed(struct block_device *bdev,
 {
 	return false;
 }
+static inline bool bdev_zone_is_offline(struct block_device *bdev,
+					sector_t sector)
+{
+	return false;
+}
 #endif /* CONFIG_BLK_DEV_ZONED */
 
 struct block_device *bdev_alloc(struct gendisk *disk, u8 partno);
-- 
2.55.0