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-rw-r--r--fs/ceph/crush/crush.h180
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diff --git a/fs/ceph/crush/crush.h b/fs/ceph/crush/crush.h
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--- a/fs/ceph/crush/crush.h
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-#ifndef CEPH_CRUSH_CRUSH_H
-#define CEPH_CRUSH_CRUSH_H
-
-#include <linux/types.h>
-
-/*
- * CRUSH is a pseudo-random data distribution algorithm that
- * efficiently distributes input values (typically, data objects)
- * across a heterogeneous, structured storage cluster.
- *
- * The algorithm was originally described in detail in this paper
- * (although the algorithm has evolved somewhat since then):
- *
- * http://www.ssrc.ucsc.edu/Papers/weil-sc06.pdf
- *
- * LGPL2
- */
-
-
-#define CRUSH_MAGIC 0x00010000ul /* for detecting algorithm revisions */
-
-
-#define CRUSH_MAX_DEPTH 10 /* max crush hierarchy depth */
-#define CRUSH_MAX_SET 10 /* max size of a mapping result */
-
-
-/*
- * CRUSH uses user-defined "rules" to describe how inputs should be
- * mapped to devices. A rule consists of sequence of steps to perform
- * to generate the set of output devices.
- */
-struct crush_rule_step {
- __u32 op;
- __s32 arg1;
- __s32 arg2;
-};
-
-/* step op codes */
-enum {
- CRUSH_RULE_NOOP = 0,
- CRUSH_RULE_TAKE = 1, /* arg1 = value to start with */
- CRUSH_RULE_CHOOSE_FIRSTN = 2, /* arg1 = num items to pick */
- /* arg2 = type */
- CRUSH_RULE_CHOOSE_INDEP = 3, /* same */
- CRUSH_RULE_EMIT = 4, /* no args */
- CRUSH_RULE_CHOOSE_LEAF_FIRSTN = 6,
- CRUSH_RULE_CHOOSE_LEAF_INDEP = 7,
-};
-
-/*
- * for specifying choose num (arg1) relative to the max parameter
- * passed to do_rule
- */
-#define CRUSH_CHOOSE_N 0
-#define CRUSH_CHOOSE_N_MINUS(x) (-(x))
-
-/*
- * The rule mask is used to describe what the rule is intended for.
- * Given a ruleset and size of output set, we search through the
- * rule list for a matching rule_mask.
- */
-struct crush_rule_mask {
- __u8 ruleset;
- __u8 type;
- __u8 min_size;
- __u8 max_size;
-};
-
-struct crush_rule {
- __u32 len;
- struct crush_rule_mask mask;
- struct crush_rule_step steps[0];
-};
-
-#define crush_rule_size(len) (sizeof(struct crush_rule) + \
- (len)*sizeof(struct crush_rule_step))
-
-
-
-/*
- * A bucket is a named container of other items (either devices or
- * other buckets). Items within a bucket are chosen using one of a
- * few different algorithms. The table summarizes how the speed of
- * each option measures up against mapping stability when items are
- * added or removed.
- *
- * Bucket Alg Speed Additions Removals
- * ------------------------------------------------
- * uniform O(1) poor poor
- * list O(n) optimal poor
- * tree O(log n) good good
- * straw O(n) optimal optimal
- */
-enum {
- CRUSH_BUCKET_UNIFORM = 1,
- CRUSH_BUCKET_LIST = 2,
- CRUSH_BUCKET_TREE = 3,
- CRUSH_BUCKET_STRAW = 4
-};
-extern const char *crush_bucket_alg_name(int alg);
-
-struct crush_bucket {
- __s32 id; /* this'll be negative */
- __u16 type; /* non-zero; type=0 is reserved for devices */
- __u8 alg; /* one of CRUSH_BUCKET_* */
- __u8 hash; /* which hash function to use, CRUSH_HASH_* */
- __u32 weight; /* 16-bit fixed point */
- __u32 size; /* num items */
- __s32 *items;
-
- /*
- * cached random permutation: used for uniform bucket and for
- * the linear search fallback for the other bucket types.
- */
- __u32 perm_x; /* @x for which *perm is defined */
- __u32 perm_n; /* num elements of *perm that are permuted/defined */
- __u32 *perm;
-};
-
-struct crush_bucket_uniform {
- struct crush_bucket h;
- __u32 item_weight; /* 16-bit fixed point; all items equally weighted */
-};
-
-struct crush_bucket_list {
- struct crush_bucket h;
- __u32 *item_weights; /* 16-bit fixed point */
- __u32 *sum_weights; /* 16-bit fixed point. element i is sum
- of weights 0..i, inclusive */
-};
-
-struct crush_bucket_tree {
- struct crush_bucket h; /* note: h.size is _tree_ size, not number of
- actual items */
- __u8 num_nodes;
- __u32 *node_weights;
-};
-
-struct crush_bucket_straw {
- struct crush_bucket h;
- __u32 *item_weights; /* 16-bit fixed point */
- __u32 *straws; /* 16-bit fixed point */
-};
-
-
-
-/*
- * CRUSH map includes all buckets, rules, etc.
- */
-struct crush_map {
- struct crush_bucket **buckets;
- struct crush_rule **rules;
-
- /*
- * Parent pointers to identify the parent bucket a device or
- * bucket in the hierarchy. If an item appears more than
- * once, this is the _last_ time it appeared (where buckets
- * are processed in bucket id order, from -1 on down to
- * -max_buckets.
- */
- __u32 *bucket_parents;
- __u32 *device_parents;
-
- __s32 max_buckets;
- __u32 max_rules;
- __s32 max_devices;
-};
-
-
-/* crush.c */
-extern int crush_get_bucket_item_weight(struct crush_bucket *b, int pos);
-extern void crush_calc_parents(struct crush_map *map);
-extern void crush_destroy_bucket_uniform(struct crush_bucket_uniform *b);
-extern void crush_destroy_bucket_list(struct crush_bucket_list *b);
-extern void crush_destroy_bucket_tree(struct crush_bucket_tree *b);
-extern void crush_destroy_bucket_straw(struct crush_bucket_straw *b);
-extern void crush_destroy_bucket(struct crush_bucket *b);
-extern void crush_destroy(struct crush_map *map);
-
-#endif