+++ /dev/null
-#ifndef _RAID5_H
-#define _RAID5_H
-
-#include <linux/raid/md.h>
-#include <linux/raid/xor.h>
-
-/*
- *
- * Each stripe contains one buffer per disc. Each buffer can be in
- * one of a number of states stored in "flags". Changes between
- * these states happen *almost* exclusively under a per-stripe
- * spinlock. Some very specific changes can happen in bi_end_io, and
- * these are not protected by the spin lock.
- *
- * The flag bits that are used to represent these states are:
- * R5_UPTODATE and R5_LOCKED
- *
- * State Empty == !UPTODATE, !LOCK
- * We have no data, and there is no active request
- * State Want == !UPTODATE, LOCK
- * A read request is being submitted for this block
- * State Dirty == UPTODATE, LOCK
- * Some new data is in this buffer, and it is being written out
- * State Clean == UPTODATE, !LOCK
- * We have valid data which is the same as on disc
- *
- * The possible state transitions are:
- *
- * Empty -> Want - on read or write to get old data for parity calc
- * Empty -> Dirty - on compute_parity to satisfy write/sync request.(RECONSTRUCT_WRITE)
- * Empty -> Clean - on compute_block when computing a block for failed drive
- * Want -> Empty - on failed read
- * Want -> Clean - on successful completion of read request
- * Dirty -> Clean - on successful completion of write request
- * Dirty -> Clean - on failed write
- * Clean -> Dirty - on compute_parity to satisfy write/sync (RECONSTRUCT or RMW)
- *
- * The Want->Empty, Want->Clean, Dirty->Clean, transitions
- * all happen in b_end_io at interrupt time.
- * Each sets the Uptodate bit before releasing the Lock bit.
- * This leaves one multi-stage transition:
- * Want->Dirty->Clean
- * This is safe because thinking that a Clean buffer is actually dirty
- * will at worst delay some action, and the stripe will be scheduled
- * for attention after the transition is complete.
- *
- * There is one possibility that is not covered by these states. That
- * is if one drive has failed and there is a spare being rebuilt. We
- * can't distinguish between a clean block that has been generated
- * from parity calculations, and a clean block that has been
- * successfully written to the spare ( or to parity when resyncing).
- * To distingush these states we have a stripe bit STRIPE_INSYNC that
- * is set whenever a write is scheduled to the spare, or to the parity
- * disc if there is no spare. A sync request clears this bit, and
- * when we find it set with no buffers locked, we know the sync is
- * complete.
- *
- * Buffers for the md device that arrive via make_request are attached
- * to the appropriate stripe in one of two lists linked on b_reqnext.
- * One list (bh_read) for read requests, one (bh_write) for write.
- * There should never be more than one buffer on the two lists
- * together, but we are not guaranteed of that so we allow for more.
- *
- * If a buffer is on the read list when the associated cache buffer is
- * Uptodate, the data is copied into the read buffer and it's b_end_io
- * routine is called. This may happen in the end_request routine only
- * if the buffer has just successfully been read. end_request should
- * remove the buffers from the list and then set the Uptodate bit on
- * the buffer. Other threads may do this only if they first check
- * that the Uptodate bit is set. Once they have checked that they may
- * take buffers off the read queue.
- *
- * When a buffer on the write list is committed for write it is copied
- * into the cache buffer, which is then marked dirty, and moved onto a
- * third list, the written list (bh_written). Once both the parity
- * block and the cached buffer are successfully written, any buffer on
- * a written list can be returned with b_end_io.
- *
- * The write list and read list both act as fifos. The read list is
- * protected by the device_lock. The write and written lists are
- * protected by the stripe lock. The device_lock, which can be
- * claimed while the stipe lock is held, is only for list
- * manipulations and will only be held for a very short time. It can
- * be claimed from interrupts.
- *
- *
- * Stripes in the stripe cache can be on one of two lists (or on
- * neither). The "inactive_list" contains stripes which are not
- * currently being used for any request. They can freely be reused
- * for another stripe. The "handle_list" contains stripes that need
- * to be handled in some way. Both of these are fifo queues. Each
- * stripe is also (potentially) linked to a hash bucket in the hash
- * table so that it can be found by sector number. Stripes that are
- * not hashed must be on the inactive_list, and will normally be at
- * the front. All stripes start life this way.
- *
- * The inactive_list, handle_list and hash bucket lists are all protected by the
- * device_lock.
- * - stripes on the inactive_list never have their stripe_lock held.
- * - stripes have a reference counter. If count==0, they are on a list.
- * - If a stripe might need handling, STRIPE_HANDLE is set.
- * - When refcount reaches zero, then if STRIPE_HANDLE it is put on
- * handle_list else inactive_list
- *
- * This, combined with the fact that STRIPE_HANDLE is only ever
- * cleared while a stripe has a non-zero count means that if the
- * refcount is 0 and STRIPE_HANDLE is set, then it is on the
- * handle_list and if recount is 0 and STRIPE_HANDLE is not set, then
- * the stripe is on inactive_list.
- *
- * The possible transitions are:
- * activate an unhashed/inactive stripe (get_active_stripe())
- * lockdev check-hash unlink-stripe cnt++ clean-stripe hash-stripe unlockdev
- * activate a hashed, possibly active stripe (get_active_stripe())
- * lockdev check-hash if(!cnt++)unlink-stripe unlockdev
- * attach a request to an active stripe (add_stripe_bh())
- * lockdev attach-buffer unlockdev
- * handle a stripe (handle_stripe())
- * lockstripe clrSTRIPE_HANDLE ...
- * (lockdev check-buffers unlockdev) ..
- * change-state ..
- * record io/ops needed unlockstripe schedule io/ops
- * release an active stripe (release_stripe())
- * lockdev if (!--cnt) { if STRIPE_HANDLE, add to handle_list else add to inactive-list } unlockdev
- *
- * The refcount counts each thread that have activated the stripe,
- * plus raid5d if it is handling it, plus one for each active request
- * on a cached buffer, and plus one if the stripe is undergoing stripe
- * operations.
- *
- * Stripe operations are performed outside the stripe lock,
- * the stripe operations are:
- * -copying data between the stripe cache and user application buffers
- * -computing blocks to save a disk access, or to recover a missing block
- * -updating the parity on a write operation (reconstruct write and
- * read-modify-write)
- * -checking parity correctness
- * -running i/o to disk
- * These operations are carried out by raid5_run_ops which uses the async_tx
- * api to (optionally) offload operations to dedicated hardware engines.
- * When requesting an operation handle_stripe sets the pending bit for the
- * operation and increments the count. raid5_run_ops is then run whenever
- * the count is non-zero.
- * There are some critical dependencies between the operations that prevent some
- * from being requested while another is in flight.
- * 1/ Parity check operations destroy the in cache version of the parity block,
- * so we prevent parity dependent operations like writes and compute_blocks
- * from starting while a check is in progress. Some dma engines can perform
- * the check without damaging the parity block, in these cases the parity
- * block is re-marked up to date (assuming the check was successful) and is
- * not re-read from disk.
- * 2/ When a write operation is requested we immediately lock the affected
- * blocks, and mark them as not up to date. This causes new read requests
- * to be held off, as well as parity checks and compute block operations.
- * 3/ Once a compute block operation has been requested handle_stripe treats
- * that block as if it is up to date. raid5_run_ops guaruntees that any
- * operation that is dependent on the compute block result is initiated after
- * the compute block completes.
- */
-
-/*
- * Operations state - intermediate states that are visible outside of sh->lock
- * In general _idle indicates nothing is running, _run indicates a data
- * processing operation is active, and _result means the data processing result
- * is stable and can be acted upon. For simple operations like biofill and
- * compute that only have an _idle and _run state they are indicated with
- * sh->state flags (STRIPE_BIOFILL_RUN and STRIPE_COMPUTE_RUN)
- */
-/**
- * enum check_states - handles syncing / repairing a stripe
- * @check_state_idle - check operations are quiesced
- * @check_state_run - check operation is running
- * @check_state_result - set outside lock when check result is valid
- * @check_state_compute_run - check failed and we are repairing
- * @check_state_compute_result - set outside lock when compute result is valid
- */
-enum check_states {
- check_state_idle = 0,
- check_state_run, /* parity check */
- check_state_check_result,
- check_state_compute_run, /* parity repair */
- check_state_compute_result,
-};
-
-/**
- * enum reconstruct_states - handles writing or expanding a stripe
- */
-enum reconstruct_states {
- reconstruct_state_idle = 0,
- reconstruct_state_prexor_drain_run, /* prexor-write */
- reconstruct_state_drain_run, /* write */
- reconstruct_state_run, /* expand */
- reconstruct_state_prexor_drain_result,
- reconstruct_state_drain_result,
- reconstruct_state_result,
-};
-
-struct stripe_head {
- struct hlist_node hash;
- struct list_head lru; /* inactive_list or handle_list */
- struct raid5_private_data *raid_conf;
- sector_t sector; /* sector of this row */
- int pd_idx; /* parity disk index */
- unsigned long state; /* state flags */
- atomic_t count; /* nr of active thread/requests */
- spinlock_t lock;
- int bm_seq; /* sequence number for bitmap flushes */
- int disks; /* disks in stripe */
- enum check_states check_state;
- enum reconstruct_states reconstruct_state;
- /* stripe_operations
- * @target - STRIPE_OP_COMPUTE_BLK target
- */
- struct stripe_operations {
- int target;
- u32 zero_sum_result;
- } ops;
- struct r5dev {
- struct bio req;
- struct bio_vec vec;
- struct page *page;
- struct bio *toread, *read, *towrite, *written;
- sector_t sector; /* sector of this page */
- unsigned long flags;
- } dev[1]; /* allocated with extra space depending of RAID geometry */
-};
-
-/* stripe_head_state - collects and tracks the dynamic state of a stripe_head
- * for handle_stripe. It is only valid under spin_lock(sh->lock);
- */
-struct stripe_head_state {
- int syncing, expanding, expanded;
- int locked, uptodate, to_read, to_write, failed, written;
- int to_fill, compute, req_compute, non_overwrite;
- int failed_num;
- unsigned long ops_request;
-};
-
-/* r6_state - extra state data only relevant to r6 */
-struct r6_state {
- int p_failed, q_failed, qd_idx, failed_num[2];
-};
-
-/* Flags */
-#define R5_UPTODATE 0 /* page contains current data */
-#define R5_LOCKED 1 /* IO has been submitted on "req" */
-#define R5_OVERWRITE 2 /* towrite covers whole page */
-/* and some that are internal to handle_stripe */
-#define R5_Insync 3 /* rdev && rdev->in_sync at start */
-#define R5_Wantread 4 /* want to schedule a read */
-#define R5_Wantwrite 5
-#define R5_Overlap 7 /* There is a pending overlapping request on this block */
-#define R5_ReadError 8 /* seen a read error here recently */
-#define R5_ReWrite 9 /* have tried to over-write the readerror */
-
-#define R5_Expanded 10 /* This block now has post-expand data */
-#define R5_Wantcompute 11 /* compute_block in progress treat as
- * uptodate
- */
-#define R5_Wantfill 12 /* dev->toread contains a bio that needs
- * filling
- */
-#define R5_Wantdrain 13 /* dev->towrite needs to be drained */
-/*
- * Write method
- */
-#define RECONSTRUCT_WRITE 1
-#define READ_MODIFY_WRITE 2
-/* not a write method, but a compute_parity mode */
-#define CHECK_PARITY 3
-
-/*
- * Stripe state
- */
-#define STRIPE_HANDLE 2
-#define STRIPE_SYNCING 3
-#define STRIPE_INSYNC 4
-#define STRIPE_PREREAD_ACTIVE 5
-#define STRIPE_DELAYED 6
-#define STRIPE_DEGRADED 7
-#define STRIPE_BIT_DELAY 8
-#define STRIPE_EXPANDING 9
-#define STRIPE_EXPAND_SOURCE 10
-#define STRIPE_EXPAND_READY 11
-#define STRIPE_IO_STARTED 12 /* do not count towards 'bypass_count' */
-#define STRIPE_FULL_WRITE 13 /* all blocks are set to be overwritten */
-#define STRIPE_BIOFILL_RUN 14
-#define STRIPE_COMPUTE_RUN 15
-/*
- * Operation request flags
- */
-#define STRIPE_OP_BIOFILL 0
-#define STRIPE_OP_COMPUTE_BLK 1
-#define STRIPE_OP_PREXOR 2
-#define STRIPE_OP_BIODRAIN 3
-#define STRIPE_OP_POSTXOR 4
-#define STRIPE_OP_CHECK 5
-
-/*
- * Plugging:
- *
- * To improve write throughput, we need to delay the handling of some
- * stripes until there has been a chance that several write requests
- * for the one stripe have all been collected.
- * In particular, any write request that would require pre-reading
- * is put on a "delayed" queue until there are no stripes currently
- * in a pre-read phase. Further, if the "delayed" queue is empty when
- * a stripe is put on it then we "plug" the queue and do not process it
- * until an unplug call is made. (the unplug_io_fn() is called).
- *
- * When preread is initiated on a stripe, we set PREREAD_ACTIVE and add
- * it to the count of prereading stripes.
- * When write is initiated, or the stripe refcnt == 0 (just in case) we
- * clear the PREREAD_ACTIVE flag and decrement the count
- * Whenever the 'handle' queue is empty and the device is not plugged, we
- * move any strips from delayed to handle and clear the DELAYED flag and set
- * PREREAD_ACTIVE.
- * In stripe_handle, if we find pre-reading is necessary, we do it if
- * PREREAD_ACTIVE is set, else we set DELAYED which will send it to the delayed queue.
- * HANDLE gets cleared if stripe_handle leave nothing locked.
- */
-
-
-struct disk_info {
- mdk_rdev_t *rdev;
-};
-
-struct raid5_private_data {
- struct hlist_head *stripe_hashtbl;
- mddev_t *mddev;
- struct disk_info *spare;
- int chunk_size, level, algorithm;
- int max_degraded;
- int raid_disks;
- int max_nr_stripes;
-
- /* used during an expand */
- sector_t expand_progress; /* MaxSector when no expand happening */
- sector_t expand_lo; /* from here up to expand_progress it out-of-bounds
- * as we haven't flushed the metadata yet
- */
- int previous_raid_disks;
-
- struct list_head handle_list; /* stripes needing handling */
- struct list_head hold_list; /* preread ready stripes */
- struct list_head delayed_list; /* stripes that have plugged requests */
- struct list_head bitmap_list; /* stripes delaying awaiting bitmap update */
- struct bio *retry_read_aligned; /* currently retrying aligned bios */
- struct bio *retry_read_aligned_list; /* aligned bios retry list */
- atomic_t preread_active_stripes; /* stripes with scheduled io */
- atomic_t active_aligned_reads;
- atomic_t pending_full_writes; /* full write backlog */
- int bypass_count; /* bypassed prereads */
- int bypass_threshold; /* preread nice */
- struct list_head *last_hold; /* detect hold_list promotions */
-
- atomic_t reshape_stripes; /* stripes with pending writes for reshape */
- /* unfortunately we need two cache names as we temporarily have
- * two caches.
- */
- int active_name;
- char cache_name[2][20];
- struct kmem_cache *slab_cache; /* for allocating stripes */
-
- int seq_flush, seq_write;
- int quiesce;
-
- int fullsync; /* set to 1 if a full sync is needed,
- * (fresh device added).
- * Cleared when a sync completes.
- */
-
- struct page *spare_page; /* Used when checking P/Q in raid6 */
-
- /*
- * Free stripes pool
- */
- atomic_t active_stripes;
- struct list_head inactive_list;
- wait_queue_head_t wait_for_stripe;
- wait_queue_head_t wait_for_overlap;
- int inactive_blocked; /* release of inactive stripes blocked,
- * waiting for 25% to be free
- */
- int pool_size; /* number of disks in stripeheads in pool */
- spinlock_t device_lock;
- struct disk_info *disks;
-};
-
-typedef struct raid5_private_data raid5_conf_t;
-
-#define mddev_to_conf(mddev) ((raid5_conf_t *) mddev->private)
-
-/*
- * Our supported algorithms
- */
-#define ALGORITHM_LEFT_ASYMMETRIC 0
-#define ALGORITHM_RIGHT_ASYMMETRIC 1
-#define ALGORITHM_LEFT_SYMMETRIC 2
-#define ALGORITHM_RIGHT_SYMMETRIC 3
-
-#endif
projects / linux-2.6-omap-h63xx.git / blobdiff