From 7603597690147a16b5cc77047d7570fa22a22673 Mon Sep 17 00:00:00 2001
From: Miao Xie <miaox@cn.fujitsu.com>
Date: Fri, 14 Nov 2014 17:45:42 +0800
Subject: [PATCH] Btrfs, replace: write raid56 parity into the replace target
 device

This function reused the code of parity scrub, and we just write
the right parity or corrected parity into the target device before
the parity scrub end.

Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
---
 fs/btrfs/raid56.c | 23 +++++++++++++++++++++++
 fs/btrfs/scrub.c  |  2 +-
 2 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/fs/btrfs/raid56.c b/fs/btrfs/raid56.c
index 89a8486c34b3..5ece565bc5f0 100644
--- a/fs/btrfs/raid56.c
+++ b/fs/btrfs/raid56.c
@@ -2318,7 +2318,9 @@ static void raid_write_parity_end_io(struct bio *bio, int err)
 static noinline void finish_parity_scrub(struct btrfs_raid_bio *rbio,
 					 int need_check)
 {
+	struct btrfs_bio *bbio = rbio->bbio;
 	void *pointers[rbio->real_stripes];
+	DECLARE_BITMAP(pbitmap, rbio->stripe_npages);
 	int nr_data = rbio->nr_data;
 	int stripe;
 	int pagenr;
@@ -2328,6 +2330,7 @@ static noinline void finish_parity_scrub(struct btrfs_raid_bio *rbio,
 	struct page *q_page = NULL;
 	struct bio_list bio_list;
 	struct bio *bio;
+	int is_replace = 0;
 	int ret;
 
 	bio_list_init(&bio_list);
@@ -2341,6 +2344,11 @@ static noinline void finish_parity_scrub(struct btrfs_raid_bio *rbio,
 		BUG();
 	}
 
+	if (bbio->num_tgtdevs && bbio->tgtdev_map[rbio->scrubp]) {
+		is_replace = 1;
+		bitmap_copy(pbitmap, rbio->dbitmap, rbio->stripe_npages);
+	}
+
 	/*
 	 * Because the higher layers(scrubber) are unlikely to
 	 * use this area of the disk again soon, so don't cache
@@ -2429,6 +2437,21 @@ static noinline void finish_parity_scrub(struct btrfs_raid_bio *rbio,
 			goto cleanup;
 	}
 
+	if (!is_replace)
+		goto submit_write;
+
+	for_each_set_bit(pagenr, pbitmap, rbio->stripe_npages) {
+		struct page *page;
+
+		page = rbio_stripe_page(rbio, rbio->scrubp, pagenr);
+		ret = rbio_add_io_page(rbio, &bio_list, page,
+				       bbio->tgtdev_map[rbio->scrubp],
+				       pagenr, rbio->stripe_len);
+		if (ret)
+			goto cleanup;
+	}
+
+submit_write:
 	nr_data = bio_list_size(&bio_list);
 	if (!nr_data) {
 		/* Every parity is right */
diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c
index 7f95afcf9fd3..0ae837fd676d 100644
--- a/fs/btrfs/scrub.c
+++ b/fs/btrfs/scrub.c
@@ -2714,7 +2714,7 @@ static void scrub_parity_check_and_repair(struct scrub_parity *sparity)
 		goto out;
 
 	length = sparity->logic_end - sparity->logic_start + 1;
-	ret = btrfs_map_sblock(sctx->dev_root->fs_info, REQ_GET_READ_MIRRORS,
+	ret = btrfs_map_sblock(sctx->dev_root->fs_info, WRITE,
 			       sparity->logic_start,
 			       &length, &bbio, 0, &raid_map);
 	if (ret || !bbio || !raid_map)
-- 
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