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813 lines
29 KiB
813 lines
29 KiB
/* SPDX-License-Identifier: GPL-2.0 */ |
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#ifndef _RAID5_H |
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#define _RAID5_H |
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|
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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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* |
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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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#define DEFAULT_STRIPE_SIZE 4096 |
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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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#if PAGE_SIZE != DEFAULT_STRIPE_SIZE |
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/* These pages will be used by bios in dev[i] */ |
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struct page **pages; |
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int nr_pages; /* page array size */ |
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int stripes_per_page; |
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#endif |
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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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unsigned int offset; /* offset of the 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_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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/* |
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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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/* |
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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 |
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* stripes until there has been a chance that several write requests |
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* for the one stripe have all been collected. |
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* In particular, any write request that would require pre-reading |
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* is put on a "delayed" queue until there are no stripes currently |
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* in a pre-read phase. Further, if the "delayed" queue is empty when |
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* a stripe is put on it then we "plug" the queue and do not process it |
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* until an unplug call is made. (the unplug_io_fn() is called). |
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* |
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* When preread is initiated on a stripe, we set PREREAD_ACTIVE and add |
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* it to the count of prereading stripes. |
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* When write is initiated, or the stripe refcnt == 0 (just in case) we |
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* clear the PREREAD_ACTIVE flag and decrement the count |
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* Whenever the 'handle' queue is empty and the device is not plugged, we |
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* move any strips from delayed to handle and clear the DELAYED flag and set |
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* PREREAD_ACTIVE. |
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* In stripe_handle, if we find pre-reading is necessary, we do it if |
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* PREREAD_ACTIVE is set, else we set DELAYED which will send it to the delayed queue. |
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* HANDLE gets cleared if stripe_handle leaves nothing locked. |
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*/ |
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|
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/* Note: disk_info.rdev can be set to NULL asynchronously by raid5_remove_disk. |
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* There are three safe ways to access disk_info.rdev. |
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* 1/ when holding mddev->reconfig_mutex |
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* 2/ when resync/recovery/reshape is known to be happening - i.e. in code that |
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* is called as part of performing resync/recovery/reshape. |
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* 3/ while holding rcu_read_lock(), use rcu_dereference to get the pointer |
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* and if it is non-NULL, increment rdev->nr_pending before dropping the RCU |
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* lock. |
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* When .rdev is set to NULL, the nr_pending count checked again and if |
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* it has been incremented, the pointer is put back in .rdev. |
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*/ |
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|
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struct disk_info { |
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struct md_rdev *rdev, *replacement; |
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struct page *extra_page; /* extra page to use in prexor */ |
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}; |
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|
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/* |
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* Stripe cache |
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*/ |
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|
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#define NR_STRIPES 256 |
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|
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#if PAGE_SIZE == DEFAULT_STRIPE_SIZE |
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#define STRIPE_SIZE PAGE_SIZE |
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#define STRIPE_SHIFT (PAGE_SHIFT - 9) |
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#define STRIPE_SECTORS (STRIPE_SIZE>>9) |
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#endif |
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#define IO_THRESHOLD 1 |
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#define BYPASS_THRESHOLD 1 |
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#define NR_HASH (PAGE_SIZE / sizeof(struct hlist_head)) |
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#define HASH_MASK (NR_HASH - 1) |
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#define MAX_STRIPE_BATCH 8 |
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|
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/* NOTE NR_STRIPE_HASH_LOCKS must remain below 64. |
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* This is because we sometimes take all the spinlocks |
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* and creating that much locking depth can cause |
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* problems. |
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*/ |
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#define NR_STRIPE_HASH_LOCKS 8 |
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#define STRIPE_HASH_LOCKS_MASK (NR_STRIPE_HASH_LOCKS - 1) |
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|
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struct r5worker { |
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struct work_struct work; |
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struct r5worker_group *group; |
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struct list_head temp_inactive_list[NR_STRIPE_HASH_LOCKS]; |
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bool working; |
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}; |
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|
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struct r5worker_group { |
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struct list_head handle_list; |
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struct list_head loprio_list; |
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struct r5conf *conf; |
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struct r5worker *workers; |
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int stripes_cnt; |
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}; |
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|
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/* |
|
* r5c journal modes of the array: write-back or write-through. |
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* write-through mode has identical behavior as existing log only |
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* implementation. |
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*/ |
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enum r5c_journal_mode { |
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R5C_JOURNAL_MODE_WRITE_THROUGH = 0, |
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R5C_JOURNAL_MODE_WRITE_BACK = 1, |
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}; |
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|
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enum r5_cache_state { |
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R5_INACTIVE_BLOCKED, /* release of inactive stripes blocked, |
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* waiting for 25% to be free |
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*/ |
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R5_ALLOC_MORE, /* It might help to allocate another |
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* stripe. |
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*/ |
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R5_DID_ALLOC, /* A stripe was allocated, don't allocate |
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* more until at least one has been |
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* released. This avoids flooding |
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* the cache. |
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*/ |
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R5C_LOG_TIGHT, /* log device space tight, need to |
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* prioritize stripes at last_checkpoint |
|
*/ |
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R5C_LOG_CRITICAL, /* log device is running out of space, |
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* only process stripes that are already |
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* occupying the log |
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*/ |
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R5C_EXTRA_PAGE_IN_USE, /* a stripe is using disk_info.extra_page |
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* for prexor |
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*/ |
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}; |
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|
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#define PENDING_IO_MAX 512 |
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#define PENDING_IO_ONE_FLUSH 128 |
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struct r5pending_data { |
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struct list_head sibling; |
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sector_t sector; /* stripe sector */ |
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struct bio_list bios; |
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}; |
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|
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struct r5conf { |
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struct hlist_head *stripe_hashtbl; |
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/* only protect corresponding hash list and inactive_list */ |
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spinlock_t hash_locks[NR_STRIPE_HASH_LOCKS]; |
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struct mddev *mddev; |
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int chunk_sectors; |
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int level, algorithm, rmw_level; |
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int max_degraded; |
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int raid_disks; |
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int max_nr_stripes; |
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int min_nr_stripes; |
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#if PAGE_SIZE != DEFAULT_STRIPE_SIZE |
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unsigned long stripe_size; |
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unsigned int stripe_shift; |
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unsigned long stripe_sectors; |
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#endif |
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|
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/* reshape_progress is the leading edge of a 'reshape' |
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* It has value MaxSector when no reshape is happening |
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* If delta_disks < 0, it is the last sector we started work on, |
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* else is it the next sector to work on. |
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*/ |
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sector_t reshape_progress; |
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/* reshape_safe is the trailing edge of a reshape. We know that |
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* before (or after) this address, all reshape has completed. |
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*/ |
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sector_t reshape_safe; |
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int previous_raid_disks; |
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int prev_chunk_sectors; |
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int prev_algo; |
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short generation; /* increments with every reshape */ |
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seqcount_spinlock_t gen_lock; /* lock against generation changes */ |
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unsigned long reshape_checkpoint; /* Time we last updated |
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* metadata */ |
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long long min_offset_diff; /* minimum difference between |
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* data_offset and |
|
* new_data_offset across all |
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* devices. May be negative, |
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* but is closest to zero. |
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*/ |
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|
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struct list_head handle_list; /* stripes needing handling */ |
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struct list_head loprio_list; /* low priority stripes */ |
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struct list_head hold_list; /* preread ready stripes */ |
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struct list_head delayed_list; /* stripes that have plugged requests */ |
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struct list_head bitmap_list; /* stripes delaying awaiting bitmap update */ |
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struct bio *retry_read_aligned; /* currently retrying aligned bios */ |
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unsigned int retry_read_offset; /* sector offset into retry_read_aligned */ |
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struct bio *retry_read_aligned_list; /* aligned bios retry list */ |
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atomic_t preread_active_stripes; /* stripes with scheduled io */ |
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atomic_t active_aligned_reads; |
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atomic_t pending_full_writes; /* full write backlog */ |
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int bypass_count; /* bypassed prereads */ |
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int bypass_threshold; /* preread nice */ |
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int skip_copy; /* Don't copy data from bio to stripe cache */ |
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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; |
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char cache_name[2][32]; |
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struct kmem_cache *slab_cache; /* for allocating stripes */ |
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struct mutex cache_size_mutex; /* Protect changes to cache size */ |
|
|
|
int seq_flush, seq_write; |
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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; |
|
}; |
|
|
|
#if PAGE_SIZE == DEFAULT_STRIPE_SIZE |
|
#define RAID5_STRIPE_SIZE(conf) STRIPE_SIZE |
|
#define RAID5_STRIPE_SHIFT(conf) STRIPE_SHIFT |
|
#define RAID5_STRIPE_SECTORS(conf) STRIPE_SECTORS |
|
#else |
|
#define RAID5_STRIPE_SIZE(conf) ((conf)->stripe_size) |
|
#define RAID5_STRIPE_SHIFT(conf) ((conf)->stripe_shift) |
|
#define RAID5_STRIPE_SECTORS(conf) ((conf)->stripe_sectors) |
|
#endif |
|
|
|
/* 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 r5conf *conf, struct bio *bio, sector_t sector) |
|
{ |
|
if (bio_end_sector(bio) < sector + RAID5_STRIPE_SECTORS(conf)) |
|
return bio->bi_next; |
|
else |
|
return NULL; |
|
} |
|
|
|
/* |
|
* 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; |
|
} |
|
|
|
#if PAGE_SIZE != DEFAULT_STRIPE_SIZE |
|
/* |
|
* Return offset of the corresponding page for r5dev. |
|
*/ |
|
static inline int raid5_get_page_offset(struct stripe_head *sh, int disk_idx) |
|
{ |
|
return (disk_idx % sh->stripes_per_page) * RAID5_STRIPE_SIZE(sh->raid_conf); |
|
} |
|
|
|
/* |
|
* Return corresponding page address for r5dev. |
|
*/ |
|
static inline struct page * |
|
raid5_get_dev_page(struct stripe_head *sh, int disk_idx) |
|
{ |
|
return sh->pages[disk_idx / sh->stripes_per_page]; |
|
} |
|
#endif |
|
|
|
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
|
|
|