1 files changed, 268 insertions, 28 deletions

diff --git a/fs/btrfs/raid56.h b/fs/btrfs/raid56.h
index ea5d73bfdfbe..1f463ecf7e41 100644
--- a/fs/btrfs/raid56.h
+++ b/fs/btrfs/raid56.h
@@ -1,51 +1,291 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 /*
  * Copyright (C) 2012 Fusion-io  All rights reserved.
  * Copyright (C) 2012 Intel Corp. All rights reserved.
+ */
+
+#ifndef BTRFS_RAID56_H
+#define BTRFS_RAID56_H
+
+#include <linux/types.h>
+#include <linux/list.h>
+#include <linux/spinlock.h>
+#include <linux/bio.h>
+#include <linux/refcount.h>
+#include <linux/workqueue.h>
+#include "volumes.h"
+
+struct page;
+struct btrfs_fs_info;
+
+enum btrfs_rbio_ops {
+	BTRFS_RBIO_WRITE,
+	BTRFS_RBIO_READ_REBUILD,
+	BTRFS_RBIO_PARITY_SCRUB,
+};
+
+/*
+ * Overview of btrfs_raid_bio.
+ *
+ * One btrfs_raid_bio represents a full stripe of RAID56, including both data
+ * and P/Q stripes. For now, each data and P/Q stripe is of a fixed length (64K).
+ *
+ * One btrfs_raid_bio can have one or more bios from higher layer, covering
+ * part or all of the data stripes.
+ *
+ * [PAGES FROM HIGHER LAYER BIOS]
+ * Higher layer bios are in the btrfs_raid_bio::bio_list.
+ *
+ * Pages from the bio_list are represented like the following:
+ *
+ * bio_list:	     |<- Bio 1 ->|             |<- Bio 2 ->|  ...
+ * bio_paddrs:	    [0]   [1]   [2]    [3]    [4]    [5]      ...
+ *
+ * If there is a bio covering a sector (one btrfs fs block), the corresponding
+ * pointer in btrfs_raid_bio::bio_paddrs[] will point to the physical address
+ * (with the offset inside the page) of the corresponding bio.
+ *
+ * If there is no bio covering a sector, then btrfs_raid_bio::bio_paddrs[i] will
+ * be INVALID_PADDR.
+ *
+ * The length of each entry in bio_paddrs[] is a step (aka, min(sectorsize, PAGE_SIZE)).
+ *
+ * [PAGES FOR INTERNAL USAGES]
+ * Pages not covered by any bio or belonging to P/Q stripes are stored in
+ * btrfs_raid_bio::stripe_pages[] and stripe_paddrs[], like the following:
+ *
+ * stripe_pages:       |<- Page 0 ->|<- Page 1 ->|  ...
+ * stripe_paddrs:     [0]    [1]   [2]    [3]   [4] ...
  *
- * 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.
+ * stripe_pages[] array stores all the pages covering the full stripe, including
+ * data and P/Q pages.
+ * stripe_pages[0] is the first page of the first data stripe.
+ * stripe_pages[BTRFS_STRIPE_LEN / PAGE_SIZE] is the first page of the second
+ * data stripe.
  *
- * 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.
+ * Some pointers inside stripe_pages[] can be NULL, e.g. for a full stripe write
+ * (the bio covers all data stripes) there is no need to allocate pages for
+ * data stripes (can grab from bio_paddrs[]).
  *
- * 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.
+ * If the corresponding page of stripe_paddrs[i] is not allocated, the value of
+ * stripe_paddrs[i] will be INVALID_PADDR.
+ *
+ * The length of each entry in stripe_paddrs[] is a step.
+ *
+ * [LOCATING A SECTOR]
+ * To locate a sector for IO, we need the following info:
+ *
+ * - stripe_nr
+ *   Starts from 0 (representing the first data stripe), ends at
+ *   @nr_data (RAID5, P stripe) or @nr_data + 1 (RAID6, Q stripe).
+ *
+ * - sector_nr
+ *   Starts from 0 (representing the first sector of the stripe), ends
+ *   at BTRFS_STRIPE_LEN / sectorsize - 1.
+ *
+ * - step_nr
+ *   A step is min(sector_size, PAGE_SIZE).
+ *
+ *   Starts from 0 (representing the first step of the sector), ends
+ *   at @sector_nsteps - 1.
+ *
+ *   For most call sites they do not need to bother this parameter.
+ *   It is for bs > ps support and only for vertical stripe related works.
+ *   (e.g. RMW/recover)
+ *
+ * - from which array
+ *   Whether grabbing from stripe_paddrs[] (aka, internal pages) or from the
+ *   bio_paddrs[] (aka, from the higher layer bios).
+ *
+ * For IO, a physical address is returned, so that we can extract the page and
+ * the offset inside the page for IO.
+ * A special value INVALID_PADDR represents when the physical address is invalid,
+ * normally meaning there is no page allocated for the specified sector.
  */
+struct btrfs_raid_bio {
+	struct btrfs_io_context *bioc;
+
+	/*
+	 * While we're doing RMW on a stripe we put it into a hash table so we
+	 * can lock the stripe and merge more rbios into it.
+	 */
+	struct list_head hash_list;
+
+	/* LRU list for the stripe cache */
+	struct list_head stripe_cache;
+
+	/* For scheduling work in the helper threads */
+	struct work_struct work;
+
+	/*
+	 * bio_list and bio_list_lock are used to add more bios into the stripe
+	 * in hopes of avoiding the full RMW
+	 */
+	struct bio_list bio_list;
+	spinlock_t bio_list_lock;
+
+	/*
+	 * Also protected by the bio_list_lock, the plug list is used by the
+	 * plugging code to collect partial bios while plugged.  The stripe
+	 * locking code also uses it to hand off the stripe lock to the next
+	 * pending IO.
+	 */
+	struct list_head plug_list;
+
+	/* Flags that tell us if it is safe to merge with this bio. */
+	unsigned long flags;
+
+	/*
+	 * Set if we're doing a parity rebuild for a read from higher up, which
+	 * is handled differently from a parity rebuild as part of RMW.
+	 */
+	enum btrfs_rbio_ops operation;
+
+	/* How many pages there are for the full stripe including P/Q */
+	u16 nr_pages;
 
-#ifndef __BTRFS_RAID56__
-#define __BTRFS_RAID56__
-static inline int nr_parity_stripes(struct map_lookup *map)
+	/* How many sectors there are for the full stripe including P/Q */
+	u16 nr_sectors;
+
+	/* Number of data stripes (no p/q) */
+	u8 nr_data;
+
+	/* Number of all stripes (including P/Q) */
+	u8 real_stripes;
+
+	/* How many pages there are for each stripe */
+	u8 stripe_npages;
+
+	/* How many sectors there are for each stripe */
+	u8 stripe_nsectors;
+
+	/*
+	 * How many steps there are for one sector.
+	 *
+	 * For bs > ps cases, it's sectorsize / PAGE_SIZE.
+	 * For bs <= ps cases, it's always 1.
+	 */
+	u8 sector_nsteps;
+
+	/* Stripe number that we're scrubbing  */
+	u8 scrubp;
+
+	/*
+	 * Size of all the bios in the bio_list.  This helps us decide if the
+	 * rbio maps to a full stripe or not.
+	 */
+	int bio_list_bytes;
+
+	refcount_t refs;
+
+	atomic_t stripes_pending;
+
+	wait_queue_head_t io_wait;
+
+	/* Bitmap to record which horizontal stripe has data */
+	unsigned long dbitmap;
+
+	/* Allocated with stripe_nsectors-many bits for finish_*() calls */
+	unsigned long finish_pbitmap;
+
+	/*
+	 * These are two arrays of pointers.  We allocate the rbio big enough
+	 * to hold them both and setup their locations when the rbio is
+	 * allocated.
+	 */
+
+	/*
+	 * Pointers to pages that we allocated for reading/writing stripes
+	 * directly from the disk (including P/Q).
+	 */
+	struct page **stripe_pages;
+
+	/* Pointers to the sectors in the bio_list, for faster lookup */
+	phys_addr_t *bio_paddrs;
+
+	/* Pointers to the sectors in the stripe_pages[]. */
+	phys_addr_t *stripe_paddrs;
+
+	/* Each set bit means the corresponding sector in stripe_sectors[] is uptodate. */
+	unsigned long *stripe_uptodate_bitmap;
+
+	/* Allocated with real_stripes-many pointers for finish_*() calls */
+	void **finish_pointers;
+
+	/*
+	 * The bitmap recording where IO errors happened.
+	 * Each bit is corresponding to one sector in either bio_sectors[] or
+	 * stripe_sectors[] array.
+	 */
+	unsigned long *error_bitmap;
+
+	/*
+	 * Checksum buffer if the rbio is for data.  The buffer should cover
+	 * all data sectors (excluding P/Q sectors).
+	 */
+	u8 *csum_buf;
+
+	/*
+	 * Each bit represents if the corresponding sector has data csum found.
+	 * Should only cover data sectors (excluding P/Q sectors).
+	 */
+	unsigned long *csum_bitmap;
+};
+
+/*
+ * For trace event usage only. Records useful debug info for each bio submitted
+ * by RAID56 to each physical device.
+ *
+ * No matter signed or not, (-1) is always the one indicating we can not grab
+ * the proper stripe number.
+ */
+struct raid56_bio_trace_info {
+	u64 devid;
+
+	/* The offset inside the stripe. (<= STRIPE_LEN) */
+	u32 offset;
+
+	/*
+	 * Stripe number.
+	 * 0 is the first data stripe, and nr_data for P stripe,
+	 * nr_data + 1 for Q stripe.
+	 * >= real_stripes for
+	 */
+	u8 stripe_nr;
+};
+
+static inline int nr_data_stripes(const struct btrfs_chunk_map *map)
 {
-	if (map->type & BTRFS_BLOCK_GROUP_RAID5)
-		return 1;
-	else if (map->type & BTRFS_BLOCK_GROUP_RAID6)
-		return 2;
-	else
-		return 0;
+	return map->num_stripes - btrfs_nr_parity_stripes(map->type);
 }
 
-static inline int nr_data_stripes(struct map_lookup *map)
+static inline int nr_bioc_data_stripes(const struct btrfs_io_context *bioc)
 {
-	return map->num_stripes - nr_parity_stripes(map);
+	return bioc->num_stripes - btrfs_nr_parity_stripes(bioc->map_type);
 }
+
 #define RAID5_P_STRIPE ((u64)-2)
 #define RAID6_Q_STRIPE ((u64)-1)
 
 #define is_parity_stripe(x) (((x) == RAID5_P_STRIPE) ||		\
 			     ((x) == RAID6_Q_STRIPE))
 
-int raid56_parity_recover(struct btrfs_root *root, struct bio *bio,
-				 struct btrfs_bio *bbio, u64 *raid_map,
-				 u64 stripe_len, int mirror_num);
-int raid56_parity_write(struct btrfs_root *root, struct bio *bio,
-			       struct btrfs_bio *bbio, u64 *raid_map,
-			       u64 stripe_len);
+struct btrfs_device;
+
+void raid56_parity_recover(struct bio *bio, struct btrfs_io_context *bioc,
+			   int mirror_num);
+void raid56_parity_write(struct bio *bio, struct btrfs_io_context *bioc);
+
+struct btrfs_raid_bio *raid56_parity_alloc_scrub_rbio(struct bio *bio,
+				struct btrfs_io_context *bioc,
+				struct btrfs_device *scrub_dev,
+				unsigned long *dbitmap, int stripe_nsectors);
+void raid56_parity_submit_scrub_rbio(struct btrfs_raid_bio *rbio);
+
+void raid56_parity_cache_data_folios(struct btrfs_raid_bio *rbio,
+				     struct folio **data_folios, u64 data_logical);
 
 int btrfs_alloc_stripe_hash_table(struct btrfs_fs_info *info);
 void btrfs_free_stripe_hash_table(struct btrfs_fs_info *info);
+
 #endif