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-rw-r--r--block/blk-lib.c30
1 files changed, 20 insertions, 10 deletions
diff --git a/block/blk-lib.c b/block/blk-lib.c
index 8411be3c19d3..7688ee3f5d72 100644
--- a/block/blk-lib.c
+++ b/block/blk-lib.c
@@ -283,24 +283,34 @@ static int __blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
* @sector: start sector
* @nr_sects: number of sectors to write
* @gfp_mask: memory allocation flags (for bio_alloc)
+ * @discard: whether to discard the block range
*
* Description:
- * Generate and issue number of bios with zerofiled pages.
+ * Zero-fill a block range. If the discard flag is set and the block
+ * device guarantees that subsequent READ operations to the block range
+ * in question will return zeroes, the blocks will be discarded. Should
+ * the discard request fail, if the discard flag is not set, or if
+ * discard_zeroes_data is not supported, this function will resort to
+ * zeroing the blocks manually, thus provisioning (allocating,
+ * anchoring) them. If the block device supports the WRITE SAME command
+ * blkdev_issue_zeroout() will use it to optimize the process of
+ * clearing the block range. Otherwise the zeroing will be performed
+ * using regular WRITE calls.
*/
int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
- sector_t nr_sects, gfp_t gfp_mask)
+ sector_t nr_sects, gfp_t gfp_mask, bool discard)
{
- if (bdev_write_same(bdev)) {
- unsigned char bdn[BDEVNAME_SIZE];
+ struct request_queue *q = bdev_get_queue(bdev);
- if (!blkdev_issue_write_same(bdev, sector, nr_sects, gfp_mask,
- ZERO_PAGE(0)))
- return 0;
+ if (discard && blk_queue_discard(q) && q->limits.discard_zeroes_data &&
+ blkdev_issue_discard(bdev, sector, nr_sects, gfp_mask, 0) == 0)
+ return 0;
- bdevname(bdev, bdn);
- pr_err("%s: WRITE SAME failed. Manually zeroing.\n", bdn);
- }
+ if (bdev_write_same(bdev) &&
+ blkdev_issue_write_same(bdev, sector, nr_sects, gfp_mask,
+ ZERO_PAGE(0)) == 0)
+ return 0;
return __blkdev_issue_zeroout(bdev, sector, nr_sects, gfp_mask);
}