sys/dev/raidframe/rf_paritymap.h

   1 /* $NetBSD$ */
   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 void rf_paritymap_attach(RF_Raid_t *, int);
 116 void rf_paritymap_detach(RF_Raid_t *); /* Not while the RAID is live! */
 117
 118 int rf_paritymap_get_disable(RF_Raid_t *);
 119 void rf_paritymap_set_disable(RF_Raid_t *, int);
 120
 121 int rf_paritymap_set_params(struct rf_paritymap *,
 122     const struct rf_pmparams *, int);
 123
 124 void rf_paritymap_init_label(struct rf_paritymap *,
 125     RF_ComponentLabel_t *);