1 files changed, 201 insertions, 0 deletions
diff --git a/fs/btrfs/raid56.h b/fs/btrfs/raid56.h
new file mode 100644
index 0000000000..45e6ff7831
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+++ b/fs/btrfs/raid56.h
@@ -0,0 +1,201 @@
+/* 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/workqueue.h>
+#include "volumes.h"
+
+enum btrfs_rbio_ops {
+	BTRFS_RBIO_WRITE,
+	BTRFS_RBIO_READ_REBUILD,
+	BTRFS_RBIO_PARITY_SCRUB,
+};
+
+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;
+
+	/* 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;
+
+	/* 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 */
+	struct sector_ptr *bio_sectors;
+
+	/*
+	 * For subpage support, we need to map each sector to above
+	 * stripe_pages.
+	 */
+	struct sector_ptr *stripe_sectors;
+
+	/* 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.
+	 *
+	 * The reason we don't use another bit in sector_ptr is, we have two
+	 * arrays of sectors, and a lot of IO can use sectors in both arrays.
+	 * Thus making it much harder to iterate.
+	 */
+	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 map_lookup *map)
+{
+	return map->num_stripes - btrfs_nr_parity_stripes(map->type);
+}
+
+static inline int nr_bioc_data_stripes(const struct btrfs_io_context *bioc)
+{
+	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))
+
+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_pages(struct btrfs_raid_bio *rbio,
+				    struct page **data_pages, 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