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b330e6a49d
The code really just wants a big flat buffer, so just do that. Link: http://lkml.kernel.org/r/20181217131929.11727-3-kent.overstreet@gmail.com Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com> Reviewed-by: Matthew Wilcox <willy@infradead.org> Cc: Shaohua Li <shli@kernel.org> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Eric Paris <eparis@parisplace.org> Cc: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> Cc: Neil Horman <nhorman@tuxdriver.com> Cc: Paul Moore <paul@paul-moore.com> Cc: Pravin B Shelar <pshelar@ovn.org> Cc: Stephen Smalley <sds@tycho.nsa.gov> Cc: Vlad Yasevich <vyasevich@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
771 lines
28 KiB
C
771 lines
28 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _RAID5_H
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#define _RAID5_H
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#include <linux/raid/xor.h>
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#include <linux/dmaengine.h>
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/*
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*
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* Each stripe contains one buffer per device. Each buffer can be in
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* one of a number of states stored in "flags". Changes between
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* these states happen *almost* exclusively under the protection of the
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* STRIPE_ACTIVE flag. Some very specific changes can happen in bi_end_io, and
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* these are not protected by STRIPE_ACTIVE.
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*
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* The flag bits that are used to represent these states are:
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* R5_UPTODATE and R5_LOCKED
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*
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* State Empty == !UPTODATE, !LOCK
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* We have no data, and there is no active request
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* State Want == !UPTODATE, LOCK
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* A read request is being submitted for this block
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* State Dirty == UPTODATE, LOCK
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* Some new data is in this buffer, and it is being written out
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* State Clean == UPTODATE, !LOCK
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* We have valid data which is the same as on disc
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*
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* The possible state transitions are:
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*
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* Empty -> Want - on read or write to get old data for parity calc
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* Empty -> Dirty - on compute_parity to satisfy write/sync request.
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* Empty -> Clean - on compute_block when computing a block for failed drive
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* Want -> Empty - on failed read
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* Want -> Clean - on successful completion of read request
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* Dirty -> Clean - on successful completion of write request
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* Dirty -> Clean - on failed write
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* Clean -> Dirty - on compute_parity to satisfy write/sync (RECONSTRUCT or RMW)
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*
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* The Want->Empty, Want->Clean, Dirty->Clean, transitions
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* all happen in b_end_io at interrupt time.
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* Each sets the Uptodate bit before releasing the Lock bit.
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* This leaves one multi-stage transition:
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* Want->Dirty->Clean
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* This is safe because thinking that a Clean buffer is actually dirty
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* will at worst delay some action, and the stripe will be scheduled
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* for attention after the transition is complete.
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*
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* There is one possibility that is not covered by these states. That
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* is if one drive has failed and there is a spare being rebuilt. We
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* can't distinguish between a clean block that has been generated
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* from parity calculations, and a clean block that has been
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* successfully written to the spare ( or to parity when resyncing).
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* To distinguish these states we have a stripe bit STRIPE_INSYNC that
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* is set whenever a write is scheduled to the spare, or to the parity
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* disc if there is no spare. A sync request clears this bit, and
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* when we find it set with no buffers locked, we know the sync is
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* complete.
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*
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* Buffers for the md device that arrive via make_request are attached
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* to the appropriate stripe in one of two lists linked on b_reqnext.
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* One list (bh_read) for read requests, one (bh_write) for write.
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* There should never be more than one buffer on the two lists
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* together, but we are not guaranteed of that so we allow for more.
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*
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* If a buffer is on the read list when the associated cache buffer is
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* Uptodate, the data is copied into the read buffer and it's b_end_io
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* routine is called. This may happen in the end_request routine only
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* if the buffer has just successfully been read. end_request should
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* remove the buffers from the list and then set the Uptodate bit on
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* the buffer. Other threads may do this only if they first check
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* that the Uptodate bit is set. Once they have checked that they may
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* take buffers off the read queue.
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*
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* When a buffer on the write list is committed for write it is copied
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* into the cache buffer, which is then marked dirty, and moved onto a
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* third list, the written list (bh_written). Once both the parity
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* block and the cached buffer are successfully written, any buffer on
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* a written list can be returned with b_end_io.
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*
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* The write list and read list both act as fifos. The read list,
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* write list and written list are protected by the device_lock.
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* The device_lock is only for list manipulations and will only be
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* held for a very short time. It can be claimed from interrupts.
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*
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*
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* Stripes in the stripe cache can be on one of two lists (or on
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* neither). The "inactive_list" contains stripes which are not
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* currently being used for any request. They can freely be reused
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* for another stripe. The "handle_list" contains stripes that need
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* to be handled in some way. Both of these are fifo queues. Each
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* stripe is also (potentially) linked to a hash bucket in the hash
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* table so that it can be found by sector number. Stripes that are
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* not hashed must be on the inactive_list, and will normally be at
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* the front. All stripes start life this way.
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*
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* The inactive_list, handle_list and hash bucket lists are all protected by the
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* device_lock.
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* - stripes have a reference counter. If count==0, they are on a list.
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* - If a stripe might need handling, STRIPE_HANDLE is set.
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* - When refcount reaches zero, then if STRIPE_HANDLE it is put on
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* handle_list else inactive_list
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*
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* This, combined with the fact that STRIPE_HANDLE is only ever
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* cleared while a stripe has a non-zero count means that if the
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* refcount is 0 and STRIPE_HANDLE is set, then it is on the
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* handle_list and if recount is 0 and STRIPE_HANDLE is not set, then
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* the stripe is on inactive_list.
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*
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* The possible transitions are:
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* activate an unhashed/inactive stripe (get_active_stripe())
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* lockdev check-hash unlink-stripe cnt++ clean-stripe hash-stripe unlockdev
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* activate a hashed, possibly active stripe (get_active_stripe())
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* lockdev check-hash if(!cnt++)unlink-stripe unlockdev
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* attach a request to an active stripe (add_stripe_bh())
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* lockdev attach-buffer unlockdev
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* handle a stripe (handle_stripe())
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* setSTRIPE_ACTIVE, clrSTRIPE_HANDLE ...
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* (lockdev check-buffers unlockdev) ..
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* change-state ..
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* record io/ops needed clearSTRIPE_ACTIVE schedule io/ops
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* release an active stripe (release_stripe())
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* lockdev if (!--cnt) { if STRIPE_HANDLE, add to handle_list else add to inactive-list } unlockdev
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*
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* The refcount counts each thread that have activated the stripe,
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* plus raid5d if it is handling it, plus one for each active request
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* on a cached buffer, and plus one if the stripe is undergoing stripe
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* operations.
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*
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* The stripe operations are:
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* -copying data between the stripe cache and user application buffers
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* -computing blocks to save a disk access, or to recover a missing block
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* -updating the parity on a write operation (reconstruct write and
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* read-modify-write)
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* -checking parity correctness
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* -running i/o to disk
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* These operations are carried out by raid5_run_ops which uses the async_tx
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* api to (optionally) offload operations to dedicated hardware engines.
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* When requesting an operation handle_stripe sets the pending bit for the
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* operation and increments the count. raid5_run_ops is then run whenever
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* the count is non-zero.
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* There are some critical dependencies between the operations that prevent some
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* from being requested while another is in flight.
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* 1/ Parity check operations destroy the in cache version of the parity block,
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* so we prevent parity dependent operations like writes and compute_blocks
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* from starting while a check is in progress. Some dma engines can perform
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* the check without damaging the parity block, in these cases the parity
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* block is re-marked up to date (assuming the check was successful) and is
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* not re-read from disk.
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* 2/ When a write operation is requested we immediately lock the affected
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* blocks, and mark them as not up to date. This causes new read requests
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* to be held off, as well as parity checks and compute block operations.
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* 3/ Once a compute block operation has been requested handle_stripe treats
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* that block as if it is up to date. raid5_run_ops guaruntees that any
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* operation that is dependent on the compute block result is initiated after
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* the compute block completes.
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*/
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/*
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* Operations state - intermediate states that are visible outside of
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* STRIPE_ACTIVE.
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* In general _idle indicates nothing is running, _run indicates a data
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* processing operation is active, and _result means the data processing result
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* is stable and can be acted upon. For simple operations like biofill and
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* compute that only have an _idle and _run state they are indicated with
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* sh->state flags (STRIPE_BIOFILL_RUN and STRIPE_COMPUTE_RUN)
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*/
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/**
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* enum check_states - handles syncing / repairing a stripe
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* @check_state_idle - check operations are quiesced
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* @check_state_run - check operation is running
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* @check_state_result - set outside lock when check result is valid
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* @check_state_compute_run - check failed and we are repairing
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* @check_state_compute_result - set outside lock when compute result is valid
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*/
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enum check_states {
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check_state_idle = 0,
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check_state_run, /* xor parity check */
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check_state_run_q, /* q-parity check */
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check_state_run_pq, /* pq dual parity check */
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check_state_check_result,
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check_state_compute_run, /* parity repair */
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check_state_compute_result,
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};
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/**
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* enum reconstruct_states - handles writing or expanding a stripe
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*/
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enum reconstruct_states {
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reconstruct_state_idle = 0,
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reconstruct_state_prexor_drain_run, /* prexor-write */
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reconstruct_state_drain_run, /* write */
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reconstruct_state_run, /* expand */
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reconstruct_state_prexor_drain_result,
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reconstruct_state_drain_result,
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reconstruct_state_result,
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};
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struct stripe_head {
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struct hlist_node hash;
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struct list_head lru; /* inactive_list or handle_list */
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struct llist_node release_list;
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struct r5conf *raid_conf;
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short generation; /* increments with every
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* reshape */
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sector_t sector; /* sector of this row */
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short pd_idx; /* parity disk index */
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short qd_idx; /* 'Q' disk index for raid6 */
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short ddf_layout;/* use DDF ordering to calculate Q */
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short hash_lock_index;
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unsigned long state; /* state flags */
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atomic_t count; /* nr of active thread/requests */
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int bm_seq; /* sequence number for bitmap flushes */
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int disks; /* disks in stripe */
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int overwrite_disks; /* total overwrite disks in stripe,
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* this is only checked when stripe
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* has STRIPE_BATCH_READY
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*/
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enum check_states check_state;
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enum reconstruct_states reconstruct_state;
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spinlock_t stripe_lock;
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int cpu;
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struct r5worker_group *group;
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struct stripe_head *batch_head; /* protected by stripe lock */
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spinlock_t batch_lock; /* only header's lock is useful */
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struct list_head batch_list; /* protected by head's batch lock*/
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union {
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struct r5l_io_unit *log_io;
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struct ppl_io_unit *ppl_io;
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};
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struct list_head log_list;
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sector_t log_start; /* first meta block on the journal */
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struct list_head r5c; /* for r5c_cache->stripe_in_journal */
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struct page *ppl_page; /* partial parity of this stripe */
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/**
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* struct stripe_operations
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* @target - STRIPE_OP_COMPUTE_BLK target
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* @target2 - 2nd compute target in the raid6 case
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* @zero_sum_result - P and Q verification flags
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* @request - async service request flags for raid_run_ops
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*/
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struct stripe_operations {
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int target, target2;
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enum sum_check_flags zero_sum_result;
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} ops;
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struct r5dev {
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/* rreq and rvec are used for the replacement device when
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* writing data to both devices.
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*/
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struct bio req, rreq;
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struct bio_vec vec, rvec;
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struct page *page, *orig_page;
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struct bio *toread, *read, *towrite, *written;
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sector_t sector; /* sector of this page */
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unsigned long flags;
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u32 log_checksum;
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unsigned short write_hint;
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} dev[1]; /* allocated with extra space depending of RAID geometry */
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};
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/* stripe_head_state - collects and tracks the dynamic state of a stripe_head
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* for handle_stripe.
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*/
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struct stripe_head_state {
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/* 'syncing' means that we need to read all devices, either
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* to check/correct parity, or to reconstruct a missing device.
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* 'replacing' means we are replacing one or more drives and
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* the source is valid at this point so we don't need to
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* read all devices, just the replacement targets.
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*/
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int syncing, expanding, expanded, replacing;
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int locked, uptodate, to_read, to_write, failed, written;
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int to_fill, compute, req_compute, non_overwrite;
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int injournal, just_cached;
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int failed_num[2];
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int p_failed, q_failed;
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int dec_preread_active;
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unsigned long ops_request;
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struct md_rdev *blocked_rdev;
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int handle_bad_blocks;
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int log_failed;
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int waiting_extra_page;
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};
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/* Flags for struct r5dev.flags */
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enum r5dev_flags {
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R5_UPTODATE, /* page contains current data */
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R5_LOCKED, /* IO has been submitted on "req" */
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R5_DOUBLE_LOCKED,/* Cannot clear R5_LOCKED until 2 writes complete */
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R5_OVERWRITE, /* towrite covers whole page */
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/* and some that are internal to handle_stripe */
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R5_Insync, /* rdev && rdev->in_sync at start */
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R5_Wantread, /* want to schedule a read */
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R5_Wantwrite,
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R5_Overlap, /* There is a pending overlapping request
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* on this block */
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R5_ReadNoMerge, /* prevent bio from merging in block-layer */
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R5_ReadError, /* seen a read error here recently */
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R5_ReWrite, /* have tried to over-write the readerror */
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R5_Expanded, /* This block now has post-expand data */
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R5_Wantcompute, /* compute_block in progress treat as
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* uptodate
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*/
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R5_Wantfill, /* dev->toread contains a bio that needs
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* filling
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*/
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R5_Wantdrain, /* dev->towrite needs to be drained */
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R5_WantFUA, /* Write should be FUA */
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R5_SyncIO, /* The IO is sync */
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R5_WriteError, /* got a write error - need to record it */
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R5_MadeGood, /* A bad block has been fixed by writing to it */
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R5_ReadRepl, /* Will/did read from replacement rather than orig */
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R5_MadeGoodRepl,/* A bad block on the replacement device has been
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* fixed by writing to it */
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R5_NeedReplace, /* This device has a replacement which is not
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* up-to-date at this stripe. */
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R5_WantReplace, /* We need to update the replacement, we have read
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* data in, and now is a good time to write it out.
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*/
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R5_Discard, /* Discard the stripe */
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R5_SkipCopy, /* Don't copy data from bio to stripe cache */
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R5_InJournal, /* data being written is in the journal device.
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* if R5_InJournal is set for parity pd_idx, all the
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* data and parity being written are in the journal
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* device
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*/
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R5_OrigPageUPTDODATE, /* with write back cache, we read old data into
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* dev->orig_page for prexor. When this flag is
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* set, orig_page contains latest data in the
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* raid disk.
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*/
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};
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/*
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* Stripe state
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*/
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enum {
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STRIPE_ACTIVE,
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STRIPE_HANDLE,
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STRIPE_SYNC_REQUESTED,
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STRIPE_SYNCING,
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STRIPE_INSYNC,
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STRIPE_REPLACED,
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STRIPE_PREREAD_ACTIVE,
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STRIPE_DELAYED,
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STRIPE_DEGRADED,
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STRIPE_BIT_DELAY,
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STRIPE_EXPANDING,
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STRIPE_EXPAND_SOURCE,
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STRIPE_EXPAND_READY,
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STRIPE_IO_STARTED, /* do not count towards 'bypass_count' */
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STRIPE_FULL_WRITE, /* all blocks are set to be overwritten */
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STRIPE_BIOFILL_RUN,
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STRIPE_COMPUTE_RUN,
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STRIPE_OPS_REQ_PENDING,
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STRIPE_ON_UNPLUG_LIST,
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STRIPE_DISCARD,
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STRIPE_ON_RELEASE_LIST,
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STRIPE_BATCH_READY,
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STRIPE_BATCH_ERR,
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STRIPE_BITMAP_PENDING, /* Being added to bitmap, don't add
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* to batch yet.
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*/
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STRIPE_LOG_TRAPPED, /* trapped into log (see raid5-cache.c)
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* this bit is used in two scenarios:
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*
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* 1. write-out phase
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* set in first entry of r5l_write_stripe
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* clear in second entry of r5l_write_stripe
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* used to bypass logic in handle_stripe
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*
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* 2. caching phase
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* set in r5c_try_caching_write()
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* clear when journal write is done
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* used to initiate r5c_cache_data()
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* also used to bypass logic in handle_stripe
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*/
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STRIPE_R5C_CACHING, /* the stripe is in caching phase
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* see more detail in the raid5-cache.c
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*/
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STRIPE_R5C_PARTIAL_STRIPE, /* in r5c cache (to-be/being handled or
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* in conf->r5c_partial_stripe_list)
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*/
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STRIPE_R5C_FULL_STRIPE, /* in r5c cache (to-be/being handled or
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* in conf->r5c_full_stripe_list)
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*/
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STRIPE_R5C_PREFLUSH, /* need to flush journal device */
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};
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#define STRIPE_EXPAND_SYNC_FLAGS \
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((1 << STRIPE_EXPAND_SOURCE) |\
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(1 << STRIPE_EXPAND_READY) |\
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(1 << STRIPE_EXPANDING) |\
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(1 << STRIPE_SYNC_REQUESTED))
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/*
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* Operation request flags
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*/
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enum {
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STRIPE_OP_BIOFILL,
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STRIPE_OP_COMPUTE_BLK,
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STRIPE_OP_PREXOR,
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STRIPE_OP_BIODRAIN,
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STRIPE_OP_RECONSTRUCT,
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STRIPE_OP_CHECK,
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STRIPE_OP_PARTIAL_PARITY,
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};
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/*
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* RAID parity calculation preferences
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*/
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enum {
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PARITY_DISABLE_RMW = 0,
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PARITY_ENABLE_RMW,
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PARITY_PREFER_RMW,
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};
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/*
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* Pages requested from set_syndrome_sources()
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*/
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enum {
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SYNDROME_SRC_ALL,
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SYNDROME_SRC_WANT_DRAIN,
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SYNDROME_SRC_WRITTEN,
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};
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/*
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* Plugging:
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*
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* 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 leaves nothing locked.
|
|
*/
|
|
|
|
/* Note: disk_info.rdev can be set to NULL asynchronously by raid5_remove_disk.
|
|
* There are three safe ways to access disk_info.rdev.
|
|
* 1/ when holding mddev->reconfig_mutex
|
|
* 2/ when resync/recovery/reshape is known to be happening - i.e. in code that
|
|
* is called as part of performing resync/recovery/reshape.
|
|
* 3/ while holding rcu_read_lock(), use rcu_dereference to get the pointer
|
|
* and if it is non-NULL, increment rdev->nr_pending before dropping the RCU
|
|
* lock.
|
|
* When .rdev is set to NULL, the nr_pending count checked again and if
|
|
* it has been incremented, the pointer is put back in .rdev.
|
|
*/
|
|
|
|
struct disk_info {
|
|
struct md_rdev *rdev, *replacement;
|
|
struct page *extra_page; /* extra page to use in prexor */
|
|
};
|
|
|
|
/*
|
|
* Stripe cache
|
|
*/
|
|
|
|
#define NR_STRIPES 256
|
|
#define STRIPE_SIZE PAGE_SIZE
|
|
#define STRIPE_SHIFT (PAGE_SHIFT - 9)
|
|
#define STRIPE_SECTORS (STRIPE_SIZE>>9)
|
|
#define IO_THRESHOLD 1
|
|
#define BYPASS_THRESHOLD 1
|
|
#define NR_HASH (PAGE_SIZE / sizeof(struct hlist_head))
|
|
#define HASH_MASK (NR_HASH - 1)
|
|
#define MAX_STRIPE_BATCH 8
|
|
|
|
/* bio's attached to a stripe+device for I/O are linked together in bi_sector
|
|
* order without overlap. There may be several bio's per stripe+device, and
|
|
* a bio could span several devices.
|
|
* When walking this list for a particular stripe+device, we must never proceed
|
|
* beyond a bio that extends past this device, as the next bio might no longer
|
|
* be valid.
|
|
* This function is used to determine the 'next' bio in the list, given the
|
|
* sector of the current stripe+device
|
|
*/
|
|
static inline struct bio *r5_next_bio(struct bio *bio, sector_t sector)
|
|
{
|
|
int sectors = bio_sectors(bio);
|
|
|
|
if (bio->bi_iter.bi_sector + sectors < sector + STRIPE_SECTORS)
|
|
return bio->bi_next;
|
|
else
|
|
return NULL;
|
|
}
|
|
|
|
/* NOTE NR_STRIPE_HASH_LOCKS must remain below 64.
|
|
* This is because we sometimes take all the spinlocks
|
|
* and creating that much locking depth can cause
|
|
* problems.
|
|
*/
|
|
#define NR_STRIPE_HASH_LOCKS 8
|
|
#define STRIPE_HASH_LOCKS_MASK (NR_STRIPE_HASH_LOCKS - 1)
|
|
|
|
struct r5worker {
|
|
struct work_struct work;
|
|
struct r5worker_group *group;
|
|
struct list_head temp_inactive_list[NR_STRIPE_HASH_LOCKS];
|
|
bool working;
|
|
};
|
|
|
|
struct r5worker_group {
|
|
struct list_head handle_list;
|
|
struct list_head loprio_list;
|
|
struct r5conf *conf;
|
|
struct r5worker *workers;
|
|
int stripes_cnt;
|
|
};
|
|
|
|
/*
|
|
* r5c journal modes of the array: write-back or write-through.
|
|
* write-through mode has identical behavior as existing log only
|
|
* implementation.
|
|
*/
|
|
enum r5c_journal_mode {
|
|
R5C_JOURNAL_MODE_WRITE_THROUGH = 0,
|
|
R5C_JOURNAL_MODE_WRITE_BACK = 1,
|
|
};
|
|
|
|
enum r5_cache_state {
|
|
R5_INACTIVE_BLOCKED, /* release of inactive stripes blocked,
|
|
* waiting for 25% to be free
|
|
*/
|
|
R5_ALLOC_MORE, /* It might help to allocate another
|
|
* stripe.
|
|
*/
|
|
R5_DID_ALLOC, /* A stripe was allocated, don't allocate
|
|
* more until at least one has been
|
|
* released. This avoids flooding
|
|
* the cache.
|
|
*/
|
|
R5C_LOG_TIGHT, /* log device space tight, need to
|
|
* prioritize stripes at last_checkpoint
|
|
*/
|
|
R5C_LOG_CRITICAL, /* log device is running out of space,
|
|
* only process stripes that are already
|
|
* occupying the log
|
|
*/
|
|
R5C_EXTRA_PAGE_IN_USE, /* a stripe is using disk_info.extra_page
|
|
* for prexor
|
|
*/
|
|
};
|
|
|
|
#define PENDING_IO_MAX 512
|
|
#define PENDING_IO_ONE_FLUSH 128
|
|
struct r5pending_data {
|
|
struct list_head sibling;
|
|
sector_t sector; /* stripe sector */
|
|
struct bio_list bios;
|
|
};
|
|
|
|
struct r5conf {
|
|
struct hlist_head *stripe_hashtbl;
|
|
/* only protect corresponding hash list and inactive_list */
|
|
spinlock_t hash_locks[NR_STRIPE_HASH_LOCKS];
|
|
struct mddev *mddev;
|
|
int chunk_sectors;
|
|
int level, algorithm, rmw_level;
|
|
int max_degraded;
|
|
int raid_disks;
|
|
int max_nr_stripes;
|
|
int min_nr_stripes;
|
|
|
|
/* reshape_progress is the leading edge of a 'reshape'
|
|
* It has value MaxSector when no reshape is happening
|
|
* If delta_disks < 0, it is the last sector we started work on,
|
|
* else is it the next sector to work on.
|
|
*/
|
|
sector_t reshape_progress;
|
|
/* reshape_safe is the trailing edge of a reshape. We know that
|
|
* before (or after) this address, all reshape has completed.
|
|
*/
|
|
sector_t reshape_safe;
|
|
int previous_raid_disks;
|
|
int prev_chunk_sectors;
|
|
int prev_algo;
|
|
short generation; /* increments with every reshape */
|
|
seqcount_t gen_lock; /* lock against generation changes */
|
|
unsigned long reshape_checkpoint; /* Time we last updated
|
|
* metadata */
|
|
long long min_offset_diff; /* minimum difference between
|
|
* data_offset and
|
|
* new_data_offset across all
|
|
* devices. May be negative,
|
|
* but is closest to zero.
|
|
*/
|
|
|
|
struct list_head handle_list; /* stripes needing handling */
|
|
struct list_head loprio_list; /* low priority stripes */
|
|
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 */
|
|
unsigned int retry_read_offset; /* sector offset into retry_read_aligned */
|
|
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 */
|
|
int skip_copy; /* Don't copy data from bio to stripe cache */
|
|
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][32];
|
|
struct kmem_cache *slab_cache; /* for allocating stripes */
|
|
struct mutex cache_size_mutex; /* Protect changes to cache size */
|
|
|
|
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.
|
|
*/
|
|
int recovery_disabled;
|
|
/* per cpu variables */
|
|
struct raid5_percpu {
|
|
struct page *spare_page; /* Used when checking P/Q in raid6 */
|
|
void *scribble; /* space for constructing buffer
|
|
* lists and performing address
|
|
* conversions
|
|
*/
|
|
int scribble_obj_size;
|
|
} __percpu *percpu;
|
|
int scribble_disks;
|
|
int scribble_sectors;
|
|
struct hlist_node node;
|
|
|
|
/*
|
|
* Free stripes pool
|
|
*/
|
|
atomic_t active_stripes;
|
|
struct list_head inactive_list[NR_STRIPE_HASH_LOCKS];
|
|
|
|
atomic_t r5c_cached_full_stripes;
|
|
struct list_head r5c_full_stripe_list;
|
|
atomic_t r5c_cached_partial_stripes;
|
|
struct list_head r5c_partial_stripe_list;
|
|
atomic_t r5c_flushing_full_stripes;
|
|
atomic_t r5c_flushing_partial_stripes;
|
|
|
|
atomic_t empty_inactive_list_nr;
|
|
struct llist_head released_stripes;
|
|
wait_queue_head_t wait_for_quiescent;
|
|
wait_queue_head_t wait_for_stripe;
|
|
wait_queue_head_t wait_for_overlap;
|
|
unsigned long cache_state;
|
|
struct shrinker shrinker;
|
|
int pool_size; /* number of disks in stripeheads in pool */
|
|
spinlock_t device_lock;
|
|
struct disk_info *disks;
|
|
struct bio_set bio_split;
|
|
|
|
/* When taking over an array from a different personality, we store
|
|
* the new thread here until we fully activate the array.
|
|
*/
|
|
struct md_thread *thread;
|
|
struct list_head temp_inactive_list[NR_STRIPE_HASH_LOCKS];
|
|
struct r5worker_group *worker_groups;
|
|
int group_cnt;
|
|
int worker_cnt_per_group;
|
|
struct r5l_log *log;
|
|
void *log_private;
|
|
|
|
spinlock_t pending_bios_lock;
|
|
bool batch_bio_dispatch;
|
|
struct r5pending_data *pending_data;
|
|
struct list_head free_list;
|
|
struct list_head pending_list;
|
|
int pending_data_cnt;
|
|
struct r5pending_data *next_pending_data;
|
|
};
|
|
|
|
|
|
/*
|
|
* Our supported algorithms
|
|
*/
|
|
#define ALGORITHM_LEFT_ASYMMETRIC 0 /* Rotating Parity N with Data Restart */
|
|
#define ALGORITHM_RIGHT_ASYMMETRIC 1 /* Rotating Parity 0 with Data Restart */
|
|
#define ALGORITHM_LEFT_SYMMETRIC 2 /* Rotating Parity N with Data Continuation */
|
|
#define ALGORITHM_RIGHT_SYMMETRIC 3 /* Rotating Parity 0 with Data Continuation */
|
|
|
|
/* Define non-rotating (raid4) algorithms. These allow
|
|
* conversion of raid4 to raid5.
|
|
*/
|
|
#define ALGORITHM_PARITY_0 4 /* P or P,Q are initial devices */
|
|
#define ALGORITHM_PARITY_N 5 /* P or P,Q are final devices. */
|
|
|
|
/* DDF RAID6 layouts differ from md/raid6 layouts in two ways.
|
|
* Firstly, the exact positioning of the parity block is slightly
|
|
* different between the 'LEFT_*' modes of md and the "_N_*" modes
|
|
* of DDF.
|
|
* Secondly, or order of datablocks over which the Q syndrome is computed
|
|
* is different.
|
|
* Consequently we have different layouts for DDF/raid6 than md/raid6.
|
|
* These layouts are from the DDFv1.2 spec.
|
|
* Interestingly DDFv1.2-Errata-A does not specify N_CONTINUE but
|
|
* leaves RLQ=3 as 'Vendor Specific'
|
|
*/
|
|
|
|
#define ALGORITHM_ROTATING_ZERO_RESTART 8 /* DDF PRL=6 RLQ=1 */
|
|
#define ALGORITHM_ROTATING_N_RESTART 9 /* DDF PRL=6 RLQ=2 */
|
|
#define ALGORITHM_ROTATING_N_CONTINUE 10 /*DDF PRL=6 RLQ=3 */
|
|
|
|
/* For every RAID5 algorithm we define a RAID6 algorithm
|
|
* with exactly the same layout for data and parity, and
|
|
* with the Q block always on the last device (N-1).
|
|
* This allows trivial conversion from RAID5 to RAID6
|
|
*/
|
|
#define ALGORITHM_LEFT_ASYMMETRIC_6 16
|
|
#define ALGORITHM_RIGHT_ASYMMETRIC_6 17
|
|
#define ALGORITHM_LEFT_SYMMETRIC_6 18
|
|
#define ALGORITHM_RIGHT_SYMMETRIC_6 19
|
|
#define ALGORITHM_PARITY_0_6 20
|
|
#define ALGORITHM_PARITY_N_6 ALGORITHM_PARITY_N
|
|
|
|
static inline int algorithm_valid_raid5(int layout)
|
|
{
|
|
return (layout >= 0) &&
|
|
(layout <= 5);
|
|
}
|
|
static inline int algorithm_valid_raid6(int layout)
|
|
{
|
|
return (layout >= 0 && layout <= 5)
|
|
||
|
|
(layout >= 8 && layout <= 10)
|
|
||
|
|
(layout >= 16 && layout <= 20);
|
|
}
|
|
|
|
static inline int algorithm_is_DDF(int layout)
|
|
{
|
|
return layout >= 8 && layout <= 10;
|
|
}
|
|
|
|
extern void md_raid5_kick_device(struct r5conf *conf);
|
|
extern int raid5_set_cache_size(struct mddev *mddev, int size);
|
|
extern sector_t raid5_compute_blocknr(struct stripe_head *sh, int i, int previous);
|
|
extern void raid5_release_stripe(struct stripe_head *sh);
|
|
extern sector_t raid5_compute_sector(struct r5conf *conf, sector_t r_sector,
|
|
int previous, int *dd_idx,
|
|
struct stripe_head *sh);
|
|
extern struct stripe_head *
|
|
raid5_get_active_stripe(struct r5conf *conf, sector_t sector,
|
|
int previous, int noblock, int noquiesce);
|
|
extern int raid5_calc_degraded(struct r5conf *conf);
|
|
extern int r5c_journal_mode_set(struct mddev *mddev, int journal_mode);
|
|
#endif
|