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      1 /* $NetBSD: rf_paritymap.h,v 1.2 2010/03/14 21:11:41 jld Exp $ */
      2 
      3 /*-
      4  * Copyright (c) 2009 Jed Davis.
      5  * All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  *
     16  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     17  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     18  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     19  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     20  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     21  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     22  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     23  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     24  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     25  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     26  * POSSIBILITY OF SUCH DAMAGE.
     27  */
     28 
     29 #include <sys/mutex.h>
     30 #include <sys/param.h>
     31 #include <sys/rwlock.h>
     32 #include <sys/types.h>
     33 
     34 #include <dev/raidframe/raidframevar.h>
     35 
     36 /* RF_PARITYMAP_N* in raidframevar.h */
     37 
     38 #define RF_PMLABEL_VALID 1
     39 #define RF_PMLABEL_WASUSED 2
     40 #define RF_PMLABEL_DISABLE 4
     41 
     42 /*
     43  * On-disk format: a single bit for each region; if the bit is clear,
     44  * then the parity is clean.
     45  */
     46 struct rf_paritymap_ondisk
     47 {
     48         /* XXX Do these really need to be volatile? */
     49 	volatile char bits[RF_PARITYMAP_NBYTE];
     50 };
     51 
     52 /* In-core per-region state: a byte for each, encoded as follows. */
     53 struct rf_paritymap_current
     54 {
     55 	volatile int8_t state[RF_PARITYMAP_NREG];
     56 	/*
     57 	 * Values:
     58 	 * if x == 0, the region may be written out as clean
     59 	 * if x > 0, then x outstanding IOs to that region
     60 	 * if x < 0, then there was recently IO; periodically increment x
     61 	 */
     62 };
     63 
     64 /* The entire state. */
     65 struct rf_paritymap
     66 {
     67 	struct rf_paritymap_ondisk *disk_boot, *disk_now;
     68 	struct rf_paritymap_current *current;
     69 
     70 	/*
     71 	 * This lock will be held while component disks' caches are
     72 	 * flushed, which could take many milliseconds, so it should
     73 	 * not be taken where that kind of delay is unacceptable.
     74 	 * Contention on this lock is not, however, expected to be a
     75 	 * performance bottleneck.
     76 	 */
     77 	kmutex_t lock;
     78 	/*
     79 	 * The flags field, below, has its own lock so that
     80 	 * inter-thread communication can occur without taking the
     81 	 * overall lock.  Ordering is lock -> lk_flags.
     82 	 */
     83 	kmutex_t lk_flags;
     84 
     85 	RF_Raid_t *raid;
     86 	daddr_t region_size;
     87 	callout_t ticker;
     88 	struct rf_pmparams params;
     89 	volatile int flags;
     90 	struct rf_pmctrs ctrs;
     91 };
     92 
     93 void rf_paritymap_status(struct rf_paritymap *, struct rf_pmstat *);
     94 
     95 int rf_paritymap_test(struct rf_paritymap *, daddr_t);
     96 void rf_paritymap_begin_region(struct rf_paritymap *, unsigned);
     97 void rf_paritymap_begin(struct rf_paritymap *, daddr_t, daddr_t);
     98 void rf_paritymap_end_region(struct rf_paritymap *, unsigned);
     99 void rf_paritymap_end(struct rf_paritymap *, daddr_t, daddr_t);
    100 
    101 void rf_paritymap_checkwork(struct rf_paritymap *);
    102 void rf_paritymap_invalidate(struct rf_paritymap *);
    103 void rf_paritymap_forceclean(struct rf_paritymap *);
    104 void rf_paritymap_write(struct rf_paritymap *);
    105 
    106 int rf_paritymap_init(struct rf_paritymap *, RF_Raid_t *,
    107     const struct rf_pmparams *);
    108 void rf_paritymap_destroy(struct rf_paritymap *, int);
    109 
    110 int rf_paritymap_rewrite(struct rf_paritymap *);
    111 
    112 int rf_paritymap_merge(struct rf_paritymap_ondisk *,
    113     struct rf_paritymap_ondisk *);
    114 
    115 int rf_paritymap_ineligible(RF_Raid_t *);
    116 void rf_paritymap_attach(RF_Raid_t *, int);
    117 void rf_paritymap_detach(RF_Raid_t *); /* Not while the RAID is live! */
    118 
    119 int rf_paritymap_get_disable(RF_Raid_t *);
    120 void rf_paritymap_set_disable(RF_Raid_t *, int);
    121 
    122 int rf_paritymap_set_params(struct rf_paritymap *,
    123     const struct rf_pmparams *, int);
    124 
    125 void rf_paritymap_init_label(struct rf_paritymap *,
    126     RF_ComponentLabel_t *);
    127