block: limit the Write Zeroes to manually writing zeroes fallback

Only fall back from hardware Write Zeroes failures when
blkdev_issue_write_zeroes returns -EOPNOTSUPP;

Note that blkdev_issue_write_zeroes turns any failure into -EOPNOTSUPP
when the write zeroes queue limit has been cleared to 0, so this still
catches all I/O errors where the driver detected missing support
for the hardware acceleration.

Signed-off-by: Christoph Hellwig <[email protected]>
Reviewed-by: Martin K. Petersen <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jens Axboe <[email protected]>

block/blk-lib.c

@@ -287,7 +287,7 @@ int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
 	if (bdev_write_zeroes_sectors(bdev)) {
 		ret = blkdev_issue_write_zeroes(bdev, sector, nr_sects,
 				gfp_mask, flags);
-		if (!ret)
+		if (ret != -EOPNOTSUPP)
 			return ret;
 	}