1 files changed, 153 insertions, 156 deletions

diff --git a/fs/btrfs/raid56.c b/fs/btrfs/raid56.c
index a7f79254ecca..df41d7049936 100644
--- a/fs/btrfs/raid56.c
+++ b/fs/btrfs/raid56.c
@@ -1,48 +1,23 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  * Copyright (C) 2012 Fusion-io  All rights reserved.
  * Copyright (C) 2012 Intel Corp. All rights reserved.
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public
- * License v2 as published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * General Public License for more details.
- *
- * You should have received a copy of the GNU General Public
- * License along with this program; if not, write to the
- * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
- * Boston, MA 021110-1307, USA.
  */
+
 #include <linux/sched.h>
-#include <linux/wait.h>
 #include <linux/bio.h>
 #include <linux/slab.h>
-#include <linux/buffer_head.h>
 #include <linux/blkdev.h>
-#include <linux/random.h>
-#include <linux/iocontext.h>
-#include <linux/capability.h>
-#include <linux/ratelimit.h>
-#include <linux/kthread.h>
 #include <linux/raid/pq.h>
 #include <linux/hash.h>
 #include <linux/list_sort.h>
 #include <linux/raid/xor.h>
 #include <linux/mm.h>
-#include <asm/div64.h>
 #include "ctree.h"
-#include "extent_map.h"
 #include "disk-io.h"
-#include "transaction.h"
-#include "print-tree.h"
 #include "volumes.h"
 #include "raid56.h"
 #include "async-thread.h"
-#include "check-integrity.h"
-#include "rcu-string.h"
 
 /* set when additional merges to this rbio are not allowed */
 #define RBIO_RMW_LOCKED_BIT	1
@@ -175,14 +150,18 @@ struct btrfs_raid_bio {
 	 * bitmap to record which horizontal stripe has data
 	 */
 	unsigned long *dbitmap;
+
+	/* allocated with real_stripes-many pointers for finish_*() calls */
+	void **finish_pointers;
+
+	/* allocated with stripe_npages-many bits for finish_*() calls */
+	unsigned long *finish_pbitmap;
 };
 
 static int __raid56_parity_recover(struct btrfs_raid_bio *rbio);
 static noinline void finish_rmw(struct btrfs_raid_bio *rbio);
 static void rmw_work(struct btrfs_work *work);
 static void read_rebuild_work(struct btrfs_work *work);
-static void async_rmw_stripe(struct btrfs_raid_bio *rbio);
-static void async_read_rebuild(struct btrfs_raid_bio *rbio);
 static int fail_bio_stripe(struct btrfs_raid_bio *rbio, struct bio *bio);
 static int fail_rbio_index(struct btrfs_raid_bio *rbio, int failed);
 static void __free_raid_bio(struct btrfs_raid_bio *rbio);
@@ -191,7 +170,13 @@ static int alloc_rbio_pages(struct btrfs_raid_bio *rbio);
 
 static noinline void finish_parity_scrub(struct btrfs_raid_bio *rbio,
 					 int need_check);
-static void async_scrub_parity(struct btrfs_raid_bio *rbio);
+static void scrub_parity_work(struct btrfs_work *work);
+
+static void start_async_work(struct btrfs_raid_bio *rbio, btrfs_func_t work_func)
+{
+	btrfs_init_work(&rbio->work, btrfs_rmw_helper, work_func, NULL, NULL);
+	btrfs_queue_work(rbio->fs_info->rmw_workers, &rbio->work);
+}
 
 /*
  * the stripe hash table is used for locking, and to collect
@@ -231,7 +216,6 @@ int btrfs_alloc_stripe_hash_table(struct btrfs_fs_info *info)
 		cur = h + i;
 		INIT_LIST_HEAD(&cur->hash_list);
 		spin_lock_init(&cur->lock);
-		init_waitqueue_head(&cur->wait);
 	}
 
 	x = cmpxchg(&info->stripe_hash_table, NULL, table);
@@ -267,7 +251,7 @@ static void cache_rbio_pages(struct btrfs_raid_bio *rbio)
 		s = kmap(rbio->bio_pages[i]);
 		d = kmap(rbio->stripe_pages[i]);
 
-		memcpy(d, s, PAGE_SIZE);
+		copy_page(d, s);
 
 		kunmap(rbio->bio_pages[i]);
 		kunmap(rbio->stripe_pages[i]);
@@ -523,32 +507,21 @@ static void run_xor(void **pages, int src_cnt, ssize_t len)
 }
 
 /*
- * returns true if the bio list inside this rbio
- * covers an entire stripe (no rmw required).
- * Must be called with the bio list lock held, or
- * at a time when you know it is impossible to add
- * new bios into the list
+ * Returns true if the bio list inside this rbio covers an entire stripe (no
+ * rmw required).
  */
-static int __rbio_is_full(struct btrfs_raid_bio *rbio)
+static int rbio_is_full(struct btrfs_raid_bio *rbio)
 {
+	unsigned long flags;
 	unsigned long size = rbio->bio_list_bytes;
 	int ret = 1;
 
+	spin_lock_irqsave(&rbio->bio_list_lock, flags);
 	if (size != rbio->nr_data * rbio->stripe_len)
 		ret = 0;
-
 	BUG_ON(size > rbio->nr_data * rbio->stripe_len);
-	return ret;
-}
-
-static int rbio_is_full(struct btrfs_raid_bio *rbio)
-{
-	unsigned long flags;
-	int ret;
-
-	spin_lock_irqsave(&rbio->bio_list_lock, flags);
-	ret = __rbio_is_full(rbio);
 	spin_unlock_irqrestore(&rbio->bio_list_lock, flags);
+
 	return ret;
 }
 
@@ -595,14 +568,31 @@ static int rbio_can_merge(struct btrfs_raid_bio *last,
 	 * bio list here, anyone else that wants to
 	 * change this stripe needs to do their own rmw.
 	 */
-	if (last->operation == BTRFS_RBIO_PARITY_SCRUB ||
-	    cur->operation == BTRFS_RBIO_PARITY_SCRUB)
+	if (last->operation == BTRFS_RBIO_PARITY_SCRUB)
 		return 0;
 
-	if (last->operation == BTRFS_RBIO_REBUILD_MISSING ||
-	    cur->operation == BTRFS_RBIO_REBUILD_MISSING)
+	if (last->operation == BTRFS_RBIO_REBUILD_MISSING)
 		return 0;
 
+	if (last->operation == BTRFS_RBIO_READ_REBUILD) {
+		int fa = last->faila;
+		int fb = last->failb;
+		int cur_fa = cur->faila;
+		int cur_fb = cur->failb;
+
+		if (last->faila >= last->failb) {
+			fa = last->failb;
+			fb = last->faila;
+		}
+
+		if (cur->faila >= cur->failb) {
+			cur_fa = cur->failb;
+			cur_fb = cur->faila;
+		}
+
+		if (fa != cur_fa || fb != cur_fb)
+			return 0;
+	}
 	return 1;
 }
 
@@ -670,7 +660,6 @@ static noinline int lock_stripe_add(struct btrfs_raid_bio *rbio)
 	struct btrfs_raid_bio *cur;
 	struct btrfs_raid_bio *pending;
 	unsigned long flags;
-	DEFINE_WAIT(wait);
 	struct btrfs_raid_bio *freeit = NULL;
 	struct btrfs_raid_bio *cache_drop = NULL;
 	int ret = 0;
@@ -803,28 +792,19 @@ static noinline void unlock_stripe(struct btrfs_raid_bio *rbio)
 			spin_unlock_irqrestore(&h->lock, flags);
 
 			if (next->operation == BTRFS_RBIO_READ_REBUILD)
-				async_read_rebuild(next);
+				start_async_work(next, read_rebuild_work);
 			else if (next->operation == BTRFS_RBIO_REBUILD_MISSING) {
 				steal_rbio(rbio, next);
-				async_read_rebuild(next);
+				start_async_work(next, read_rebuild_work);
 			} else if (next->operation == BTRFS_RBIO_WRITE) {
 				steal_rbio(rbio, next);
-				async_rmw_stripe(next);
+				start_async_work(next, rmw_work);
 			} else if (next->operation == BTRFS_RBIO_PARITY_SCRUB) {
 				steal_rbio(rbio, next);
-				async_scrub_parity(next);
+				start_async_work(next, scrub_parity_work);
 			}
 
 			goto done_nolock;
-			/*
-			 * The barrier for this waitqueue_active is not needed,
-			 * we're protected by h->lock and can't miss a wakeup.
-			 */
-		} else if (waitqueue_active(&h->wait)) {
-			spin_unlock(&rbio->bio_list_lock);
-			spin_unlock_irqrestore(&h->lock, flags);
-			wake_up(&h->wait);
-			goto done_nolock;
 		}
 	}
 done:
@@ -858,10 +838,17 @@ static void __free_raid_bio(struct btrfs_raid_bio *rbio)
 	kfree(rbio);
 }
 
-static void free_raid_bio(struct btrfs_raid_bio *rbio)
+static void rbio_endio_bio_list(struct bio *cur, blk_status_t err)
 {
-	unlock_stripe(rbio);
-	__free_raid_bio(rbio);
+	struct bio *next;
+
+	while (cur) {
+		next = cur->bi_next;
+		cur->bi_next = NULL;
+		cur->bi_status = err;
+		bio_endio(cur);
+		cur = next;
+	}
 }
 
 /*
@@ -871,20 +858,26 @@ static void free_raid_bio(struct btrfs_raid_bio *rbio)
 static void rbio_orig_end_io(struct btrfs_raid_bio *rbio, blk_status_t err)
 {
 	struct bio *cur = bio_list_get(&rbio->bio_list);
-	struct bio *next;
+	struct bio *extra;
 
 	if (rbio->generic_bio_cnt)
 		btrfs_bio_counter_sub(rbio->fs_info, rbio->generic_bio_cnt);
 
-	free_raid_bio(rbio);
+	/*
+	 * At this moment, rbio->bio_list is empty, however since rbio does not
+	 * always have RBIO_RMW_LOCKED_BIT set and rbio is still linked on the
+	 * hash list, rbio may be merged with others so that rbio->bio_list
+	 * becomes non-empty.
+	 * Once unlock_stripe() is done, rbio->bio_list will not be updated any
+	 * more and we can call bio_endio() on all queued bios.
+	 */
+	unlock_stripe(rbio);
+	extra = bio_list_get(&rbio->bio_list);
+	__free_raid_bio(rbio);
 
-	while (cur) {
-		next = cur->bi_next;
-		cur->bi_next = NULL;
-		cur->bi_status = err;
-		bio_endio(cur);
-		cur = next;
-	}
+	rbio_endio_bio_list(cur, err);
+	if (extra)
+		rbio_endio_bio_list(extra, err);
 }
 
 /*
@@ -974,9 +967,14 @@ static struct btrfs_raid_bio *alloc_rbio(struct btrfs_fs_info *fs_info,
 	int stripe_npages = DIV_ROUND_UP(stripe_len, PAGE_SIZE);
 	void *p;
 
-	rbio = kzalloc(sizeof(*rbio) + num_pages * sizeof(struct page *) * 2 +
-		       DIV_ROUND_UP(stripe_npages, BITS_PER_LONG) *
-		       sizeof(long), GFP_NOFS);
+	rbio = kzalloc(sizeof(*rbio) +
+		       sizeof(*rbio->stripe_pages) * num_pages +
+		       sizeof(*rbio->bio_pages) * num_pages +
+		       sizeof(*rbio->finish_pointers) * real_stripes +
+		       sizeof(*rbio->dbitmap) * BITS_TO_LONGS(stripe_npages) +
+		       sizeof(*rbio->finish_pbitmap) *
+				BITS_TO_LONGS(stripe_npages),
+		       GFP_NOFS);
 	if (!rbio)
 		return ERR_PTR(-ENOMEM);
 
@@ -998,13 +996,20 @@ static struct btrfs_raid_bio *alloc_rbio(struct btrfs_fs_info *fs_info,
 	atomic_set(&rbio->stripes_pending, 0);
 
 	/*
-	 * the stripe_pages and bio_pages array point to the extra
+	 * the stripe_pages, bio_pages, etc arrays point to the extra
 	 * memory we allocated past the end of the rbio
 	 */
 	p = rbio + 1;
-	rbio->stripe_pages = p;
-	rbio->bio_pages = p + sizeof(struct page *) * num_pages;
-	rbio->dbitmap = p + sizeof(struct page *) * num_pages * 2;
+#define CONSUME_ALLOC(ptr, count)	do {				\
+		ptr = p;						\
+		p = (unsigned char *)p + sizeof(*(ptr)) * (count);	\
+	} while (0)
+	CONSUME_ALLOC(rbio->stripe_pages, num_pages);
+	CONSUME_ALLOC(rbio->bio_pages, num_pages);
+	CONSUME_ALLOC(rbio->finish_pointers, real_stripes);
+	CONSUME_ALLOC(rbio->dbitmap, BITS_TO_LONGS(stripe_npages));
+	CONSUME_ALLOC(rbio->finish_pbitmap, BITS_TO_LONGS(stripe_npages));
+#undef  CONSUME_ALLOC
 
 	if (bbio->map_type & BTRFS_BLOCK_GROUP_RAID5)
 		nr_data = real_stripes - 1;
@@ -1173,7 +1178,7 @@ static void index_rbio_pages(struct btrfs_raid_bio *rbio)
 static noinline void finish_rmw(struct btrfs_raid_bio *rbio)
 {
 	struct btrfs_bio *bbio = rbio->bbio;
-	void *pointers[rbio->real_stripes];
+	void **pointers = rbio->finish_pointers;
 	int nr_data = rbio->nr_data;
 	int stripe;
 	int pagenr;
@@ -1250,7 +1255,7 @@ static noinline void finish_rmw(struct btrfs_raid_bio *rbio)
 						pointers);
 		} else {
 			/* raid5 */
-			memcpy(pointers[nr_data], pointers[0], PAGE_SIZE);
+			copy_page(pointers[nr_data], pointers[0]);
 			run_xor(pointers + 1, nr_data - 1, PAGE_SIZE);
 		}
 
@@ -1318,7 +1323,7 @@ write_data:
 
 		bio->bi_private = rbio;
 		bio->bi_end_io = raid_write_end_io;
-		bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
+		bio->bi_opf = REQ_OP_WRITE;
 
 		submit_bio(bio);
 	}
@@ -1351,6 +1356,7 @@ static int find_bio_stripe(struct btrfs_raid_bio *rbio,
 		stripe_start = stripe->physical;
 		if (physical >= stripe_start &&
 		    physical < stripe_start + rbio->stripe_len &&
+		    stripe->dev->bdev &&
 		    bio->bi_disk == stripe->dev->bdev->bd_disk &&
 		    bio->bi_partno == stripe->dev->bdev->bd_partno) {
 			return i;
@@ -1435,14 +1441,13 @@ static int fail_bio_stripe(struct btrfs_raid_bio *rbio,
  */
 static void set_bio_pages_uptodate(struct bio *bio)
 {
-	struct bio_vec bvec;
-	struct bvec_iter iter;
+	struct bio_vec *bvec;
+	int i;
 
-	if (bio_flagged(bio, BIO_CLONED))
-		bio->bi_iter = btrfs_io_bio(bio)->iter;
+	ASSERT(!bio_flagged(bio, BIO_CLONED));
 
-	bio_for_each_segment(bvec, bio, iter)
-		SetPageUptodate(bvec.bv_page);
+	bio_for_each_segment_all(bvec, bio, i)
+		SetPageUptodate(bvec->bv_page);
 }
 
 /*
@@ -1483,20 +1488,6 @@ cleanup:
 	rbio_orig_end_io(rbio, BLK_STS_IOERR);
 }
 
-static void async_rmw_stripe(struct btrfs_raid_bio *rbio)
-{
-	btrfs_init_work(&rbio->work, btrfs_rmw_helper, rmw_work, NULL, NULL);
-	btrfs_queue_work(rbio->fs_info->rmw_workers, &rbio->work);
-}
-
-static void async_read_rebuild(struct btrfs_raid_bio *rbio)
-{
-	btrfs_init_work(&rbio->work, btrfs_rmw_helper,
-			read_rebuild_work, NULL, NULL);
-
-	btrfs_queue_work(rbio->fs_info->rmw_workers, &rbio->work);
-}
-
 /*
  * the stripe must be locked by the caller.  It will
  * unlock after all the writes are done
@@ -1574,7 +1565,7 @@ static int raid56_rmw_stripe(struct btrfs_raid_bio *rbio)
 
 		bio->bi_private = rbio;
 		bio->bi_end_io = raid_rmw_end_io;
-		bio_set_op_attrs(bio, REQ_OP_READ, 0);
+		bio->bi_opf = REQ_OP_READ;
 
 		btrfs_bio_wq_end_io(rbio->fs_info, bio, BTRFS_WQ_ENDIO_RAID56);
 
@@ -1627,7 +1618,7 @@ static int partial_stripe_write(struct btrfs_raid_bio *rbio)
 
 	ret = lock_stripe_add(rbio);
 	if (ret == 0)
-		async_rmw_stripe(rbio);
+		start_async_work(rbio, rmw_work);
 	return 0;
 }
 
@@ -1695,8 +1686,11 @@ static void run_plug(struct btrfs_plug_cb *plug)
 		list_del_init(&cur->plug_list);
 
 		if (rbio_is_full(cur)) {
+			int ret;
+
 			/* we have a full stripe, send it down */
-			full_stripe_write(cur);
+			ret = full_stripe_write(cur);
+			BUG_ON(ret);
 			continue;
 		}
 		if (last) {
@@ -1916,9 +1910,7 @@ static void __raid_recover_end_io(struct btrfs_raid_bio *rbio)
 			BUG_ON(failb != -1);
 pstripe:
 			/* Copy parity block into failed block to start with */
-			memcpy(pointers[faila],
-			       pointers[rbio->nr_data],
-			       PAGE_SIZE);
+			copy_page(pointers[faila], pointers[rbio->nr_data]);
 
 			/* rearrange the pointer array */
 			p = pointers[faila];
@@ -1968,15 +1960,34 @@ cleanup:
 	kfree(pointers);
 
 cleanup_io:
-	if (rbio->operation == BTRFS_RBIO_READ_REBUILD) {
-		if (err == BLK_STS_OK)
+	/*
+	 * Similar to READ_REBUILD, REBUILD_MISSING at this point also has a
+	 * valid rbio which is consistent with ondisk content, thus such a
+	 * valid rbio can be cached to avoid further disk reads.
+	 */
+	if (rbio->operation == BTRFS_RBIO_READ_REBUILD ||
+	    rbio->operation == BTRFS_RBIO_REBUILD_MISSING) {
+		/*
+		 * - In case of two failures, where rbio->failb != -1:
+		 *
+		 *   Do not cache this rbio since the above read reconstruction
+		 *   (raid6_datap_recov() or raid6_2data_recov()) may have
+		 *   changed some content of stripes which are not identical to
+		 *   on-disk content any more, otherwise, a later write/recover
+		 *   may steal stripe_pages from this rbio and end up with
+		 *   corruptions or rebuild failures.
+		 *
+		 * - In case of single failure, where rbio->failb == -1:
+		 *
+		 *   Cache this rbio iff the above read reconstruction is
+		 *   excuted without problems.
+		 */
+		if (err == BLK_STS_OK && rbio->failb < 0)
 			cache_rbio_pages(rbio);
 		else
 			clear_bit(RBIO_CACHE_READY_BIT, &rbio->flags);
 
 		rbio_orig_end_io(rbio, err);
-	} else if (rbio->operation == BTRFS_RBIO_REBUILD_MISSING) {
-		rbio_orig_end_io(rbio, err);
 	} else if (err == BLK_STS_OK) {
 		rbio->faila = -1;
 		rbio->failb = -1;
@@ -2101,7 +2112,7 @@ static int __raid56_parity_recover(struct btrfs_raid_bio *rbio)
 
 		bio->bi_private = rbio;
 		bio->bi_end_io = raid_recover_end_io;
-		bio_set_op_attrs(bio, REQ_OP_READ, 0);
+		bio->bi_opf = REQ_OP_READ;
 
 		btrfs_bio_wq_end_io(rbio->fs_info, bio, BTRFS_WQ_ENDIO_RAID56);
 
@@ -2170,11 +2181,21 @@ int raid56_parity_recover(struct btrfs_fs_info *fs_info, struct bio *bio,
 	}
 
 	/*
-	 * reconstruct from the q stripe if they are
-	 * asking for mirror 3
+	 * Loop retry:
+	 * for 'mirror == 2', reconstruct from all other stripes.
+	 * for 'mirror_num > 2', select a stripe to fail on every retry.
 	 */
-	if (mirror_num == 3)
-		rbio->failb = rbio->real_stripes - 2;
+	if (mirror_num > 2) {
+		/*
+		 * 'mirror == 3' is to fail the p stripe and
+		 * reconstruct from the q stripe.  'mirror > 3' is to
+		 * fail a data stripe and reconstruct from p+q stripe.
+		 */
+		rbio->failb = rbio->real_stripes - (mirror_num - 1);
+		ASSERT(rbio->failb > 0);
+		if (rbio->failb <= rbio->faila)
+			rbio->failb--;
+	}
 
 	ret = lock_stripe_add(rbio);
 
@@ -2314,8 +2335,8 @@ 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);
+	void **pointers = rbio->finish_pointers;
+	unsigned long *pbitmap = rbio->finish_pbitmap;
 	int nr_data = rbio->nr_data;
 	int stripe;
 	int pagenr;
@@ -2394,7 +2415,7 @@ static noinline void finish_parity_scrub(struct btrfs_raid_bio *rbio,
 						pointers);
 		} else {
 			/* raid5 */
-			memcpy(pointers[nr_data], pointers[0], PAGE_SIZE);
+			copy_page(pointers[nr_data], pointers[0]);
 			run_xor(pointers + 1, nr_data - 1, PAGE_SIZE);
 		}
 
@@ -2402,7 +2423,7 @@ static noinline void finish_parity_scrub(struct btrfs_raid_bio *rbio,
 		p = rbio_stripe_page(rbio, rbio->scrubp, pagenr);
 		parity = kmap(p);
 		if (memcmp(parity, pointers[rbio->scrubp], PAGE_SIZE))
-			memcpy(parity, pointers[rbio->scrubp], PAGE_SIZE);
+			copy_page(parity, pointers[rbio->scrubp]);
 		else
 			/* Parity is right, needn't writeback */
 			bitmap_clear(rbio->dbitmap, pagenr, 1);
@@ -2463,7 +2484,7 @@ submit_write:
 
 		bio->bi_private = rbio;
 		bio->bi_end_io = raid_write_end_io;
-		bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
+		bio->bi_opf = REQ_OP_WRITE;
 
 		submit_bio(bio);
 	}
@@ -2645,7 +2666,7 @@ static void raid56_parity_scrub_stripe(struct btrfs_raid_bio *rbio)
 
 		bio->bi_private = rbio;
 		bio->bi_end_io = raid56_parity_scrub_end_io;
-		bio_set_op_attrs(bio, REQ_OP_READ, 0);
+		bio->bi_opf = REQ_OP_READ;
 
 		btrfs_bio_wq_end_io(rbio->fs_info, bio, BTRFS_WQ_ENDIO_RAID56);
 
@@ -2674,18 +2695,10 @@ static void scrub_parity_work(struct btrfs_work *work)
 	raid56_parity_scrub_stripe(rbio);
 }
 
-static void async_scrub_parity(struct btrfs_raid_bio *rbio)
-{
-	btrfs_init_work(&rbio->work, btrfs_rmw_helper,
-			scrub_parity_work, NULL, NULL);
-
-	btrfs_queue_work(rbio->fs_info->rmw_workers, &rbio->work);
-}
-
 void raid56_parity_submit_scrub_rbio(struct btrfs_raid_bio *rbio)
 {
 	if (!lock_stripe_add(rbio))
-		async_scrub_parity(rbio);
+		start_async_work(rbio, scrub_parity_work);
 }
 
 /* The following code is used for dev replace of a missing RAID 5/6 device. */
@@ -2724,24 +2737,8 @@ raid56_alloc_missing_rbio(struct btrfs_fs_info *fs_info, struct bio *bio,
 	return rbio;
 }
 
-static void missing_raid56_work(struct btrfs_work *work)
-{
-	struct btrfs_raid_bio *rbio;
-
-	rbio = container_of(work, struct btrfs_raid_bio, work);
-	__raid56_parity_recover(rbio);
-}
-
-static void async_missing_raid56(struct btrfs_raid_bio *rbio)
-{
-	btrfs_init_work(&rbio->work, btrfs_rmw_helper,
-			missing_raid56_work, NULL, NULL);
-
-	btrfs_queue_work(rbio->fs_info->rmw_workers, &rbio->work);
-}
-
 void raid56_submit_missing_rbio(struct btrfs_raid_bio *rbio)
 {
 	if (!lock_stripe_add(rbio))
-		async_missing_raid56(rbio);
+		start_async_work(rbio, read_rebuild_work);
 }