1 files changed, 373 insertions, 0 deletions

diff --git a/include/uapi/linux/bcache.h b/include/uapi/linux/bcache.h
new file mode 100644
index 000000000000..164a7e263988
--- /dev/null
+++ b/include/uapi/linux/bcache.h
@@ -0,0 +1,373 @@
+#ifndef _LINUX_BCACHE_H
+#define _LINUX_BCACHE_H
+
+/*
+ * Bcache on disk data structures
+ */
+
+#include <asm/types.h>
+
+#define BITMASK(name, type, field, offset, size)                \
+static inline __u64 name(const type *k)                         \
+{ return (k->field >> offset) & ~(~0ULL << size); }             \
+                                                                \
+static inline void SET_##name(type *k, __u64 v)                 \
+{                                                               \
+        k->field &= ~(~(~0ULL << size) << offset);              \
+        k->field |= (v & ~(~0ULL << size)) << offset;           \
+}
+
+/* Btree keys - all units are in sectors */
+
+struct bkey {
+        __u64   high;
+        __u64   low;
+        __u64   ptr[];
+};
+
+#define KEY_FIELD(name, field, offset, size)                            \
+        BITMASK(name, struct bkey, field, offset, size)
+
+#define PTR_FIELD(name, offset, size)                                   \
+static inline __u64 name(const struct bkey *k, unsigned i)              \
+{ return (k->ptr[i] >> offset) & ~(~0ULL << size); }                    \
+                                                                        \
+static inline void SET_##name(struct bkey *k, unsigned i, __u64 v)      \
+{                                                                       \
+        k->ptr[i] &= ~(~(~0ULL << size) << offset);                     \
+        k->ptr[i] |= (v & ~(~0ULL << size)) << offset;                  \
+}
+
+#define KEY_SIZE_BITS           16
+
+KEY_FIELD(KEY_PTRS,     high, 60, 3)
+KEY_FIELD(HEADER_SIZE,  high, 58, 2)
+KEY_FIELD(KEY_CSUM,     high, 56, 2)
+KEY_FIELD(KEY_PINNED,   high, 55, 1)
+KEY_FIELD(KEY_DIRTY,    high, 36, 1)
+
+KEY_FIELD(KEY_SIZE,     high, 20, KEY_SIZE_BITS)
+KEY_FIELD(KEY_INODE,    high, 0,  20)
+
+/* Next time I change the on disk format, KEY_OFFSET() won't be 64 bits */
+
+static inline __u64 KEY_OFFSET(const struct bkey *k)
+{
+        return k->low;
+}
+
+static inline void SET_KEY_OFFSET(struct bkey *k, __u64 v)
+{
+        k->low = v;
+}
+
+/*
+ * The high bit being set is a relic from when we used it to do binary
+ * searches - it told you where a key started. It's not used anymore,
+ * and can probably be safely dropped.
+ */
+#define KEY(inode, offset, size)                                        \
+((struct bkey) {                                                        \
+        .high = (1ULL << 63) | ((__u64) (size) << 20) | (inode),        \
+        .low = (offset)                                                 \
+})
+
+#define ZERO_KEY                        KEY(0, 0, 0)
+
+#define MAX_KEY_INODE                   (~(~0 << 20))
+#define MAX_KEY_OFFSET                  (~0ULL >> 1)
+#define MAX_KEY                         KEY(MAX_KEY_INODE, MAX_KEY_OFFSET, 0)
+
+#define KEY_START(k)                    (KEY_OFFSET(k) - KEY_SIZE(k))
+#define START_KEY(k)                    KEY(KEY_INODE(k), KEY_START(k), 0)
+
+#define PTR_DEV_BITS                    12
+
+PTR_FIELD(PTR_DEV,                      51, PTR_DEV_BITS)
+PTR_FIELD(PTR_OFFSET,                   8,  43)
+PTR_FIELD(PTR_GEN,                      0,  8)
+
+#define PTR_CHECK_DEV                   ((1 << PTR_DEV_BITS) - 1)
+
+#define PTR(gen, offset, dev)                                           \
+        ((((__u64) dev) << 51) | ((__u64) offset) << 8 | gen)
+
+/* Bkey utility code */
+
+static inline unsigned long bkey_u64s(const struct bkey *k)
+{
+        return (sizeof(struct bkey) / sizeof(__u64)) + KEY_PTRS(k);
+}
+
+static inline unsigned long bkey_bytes(const struct bkey *k)
+{
+        return bkey_u64s(k) * sizeof(__u64);
+}
+
+#define bkey_copy(_dest, _src)  memcpy(_dest, _src, bkey_bytes(_src))
+
+static inline void bkey_copy_key(struct bkey *dest, const struct bkey *src)
+{
+        SET_KEY_INODE(dest, KEY_INODE(src));
+        SET_KEY_OFFSET(dest, KEY_OFFSET(src));
+}
+
+static inline struct bkey *bkey_next(const struct bkey *k)
+{
+        __u64 *d = (void *) k;
+        return (struct bkey *) (d + bkey_u64s(k));
+}
+
+static inline struct bkey *bkey_last(const struct bkey *k, unsigned nr_keys)
+{
+        __u64 *d = (void *) k;
+        return (struct bkey *) (d + nr_keys);
+}
+/* Enough for a key with 6 pointers */
+#define BKEY_PAD                8
+
+#define BKEY_PADDED(key)                                        \
+        union { struct bkey key; __u64 key ## _pad[BKEY_PAD]; }
+
+/* Superblock */
+
+/* Version 0: Cache device
+ * Version 1: Backing device
+ * Version 2: Seed pointer into btree node checksum
+ * Version 3: Cache device with new UUID format
+ * Version 4: Backing device with data offset
+ */
+#define BCACHE_SB_VERSION_CDEV          0
+#define BCACHE_SB_VERSION_BDEV          1
+#define BCACHE_SB_VERSION_CDEV_WITH_UUID 3
+#define BCACHE_SB_VERSION_BDEV_WITH_OFFSET 4
+#define BCACHE_SB_MAX_VERSION           4
+
+#define SB_SECTOR                       8
+#define SB_SIZE                         4096
+#define SB_LABEL_SIZE                   32
+#define SB_JOURNAL_BUCKETS              256U
+/* SB_JOURNAL_BUCKETS must be divisible by BITS_PER_LONG */
+#define MAX_CACHES_PER_SET              8
+
+#define BDEV_DATA_START_DEFAULT         16      /* sectors */
+
+struct cache_sb {
+        __u64                   csum;
+        __u64                   offset; /* sector where this sb was written */
+        __u64                   version;
+
+        __u8                    magic[16];
+
+        __u8                    uuid[16];
+        union {
+                __u8            set_uuid[16];
+                __u64           set_magic;
+        };
+        __u8                    label[SB_LABEL_SIZE];
+
+        __u64                   flags;
+        __u64                   seq;
+        __u64                   pad[8];
+
+        union {
+        struct {
+                /* Cache devices */
+                __u64           nbuckets;       /* device size */
+
+                __u16           block_size;     /* sectors */
+                __u16           bucket_size;    /* sectors */
+
+                __u16           nr_in_set;
+                __u16           nr_this_dev;
+        };
+        struct {
+                /* Backing devices */
+                __u64           data_offset;
+
+                /*
+                 * block_size from the cache device section is still used by
+                 * backing devices, so don't add anything here until we fix
+                 * things to not need it for backing devices anymore
+                 */
+        };
+        };
+
+        __u32                   last_mount;     /* time_t */
+
+        __u16                   first_bucket;
+        union {
+                __u16           njournal_buckets;
+                __u16           keys;
+        };
+        __u64                   d[SB_JOURNAL_BUCKETS];  /* journal buckets */
+};
+
+static inline _Bool SB_IS_BDEV(const struct cache_sb *sb)
+{
+        return sb->version == BCACHE_SB_VERSION_BDEV
+                || sb->version == BCACHE_SB_VERSION_BDEV_WITH_OFFSET;
+}
+
+BITMASK(CACHE_SYNC,                     struct cache_sb, flags, 0, 1);
+BITMASK(CACHE_DISCARD,                  struct cache_sb, flags, 1, 1);
+BITMASK(CACHE_REPLACEMENT,              struct cache_sb, flags, 2, 3);
+#define CACHE_REPLACEMENT_LRU           0U
+#define CACHE_REPLACEMENT_FIFO          1U
+#define CACHE_REPLACEMENT_RANDOM        2U
+
+BITMASK(BDEV_CACHE_MODE,                struct cache_sb, flags, 0, 4);
+#define CACHE_MODE_WRITETHROUGH         0U
+#define CACHE_MODE_WRITEBACK            1U
+#define CACHE_MODE_WRITEAROUND          2U
+#define CACHE_MODE_NONE                 3U
+BITMASK(BDEV_STATE,                     struct cache_sb, flags, 61, 2);
+#define BDEV_STATE_NONE                 0U
+#define BDEV_STATE_CLEAN                1U
+#define BDEV_STATE_DIRTY                2U
+#define BDEV_STATE_STALE                3U
+
+/*
+ * Magic numbers
+ *
+ * The various other data structures have their own magic numbers, which are
+ * xored with the first part of the cache set's UUID
+ */
+
+#define JSET_MAGIC                      0x245235c1a3625032ULL
+#define PSET_MAGIC                      0x6750e15f87337f91ULL
+#define BSET_MAGIC                      0x90135c78b99e07f5ULL
+
+static inline __u64 jset_magic(struct cache_sb *sb)
+{
+        return sb->set_magic ^ JSET_MAGIC;
+}
+
+static inline __u64 pset_magic(struct cache_sb *sb)
+{
+        return sb->set_magic ^ PSET_MAGIC;
+}
+
+static inline __u64 bset_magic(struct cache_sb *sb)
+{
+        return sb->set_magic ^ BSET_MAGIC;
+}
+
+/*
+ * Journal
+ *
+ * On disk format for a journal entry:
+ * seq is monotonically increasing; every journal entry has its own unique
+ * sequence number.
+ *
+ * last_seq is the oldest journal entry that still has keys the btree hasn't
+ * flushed to disk yet.
+ *
+ * version is for on disk format changes.
+ */
+
+#define BCACHE_JSET_VERSION_UUIDv1      1
+#define BCACHE_JSET_VERSION_UUID        1       /* Always latest UUID format */
+#define BCACHE_JSET_VERSION             1
+
+struct jset {
+        __u64                   csum;
+        __u64                   magic;
+        __u64                   seq;
+        __u32                   version;
+        __u32                   keys;
+
+        __u64                   last_seq;
+
+        BKEY_PADDED(uuid_bucket);
+        BKEY_PADDED(btree_root);
+        __u16                   btree_level;
+        __u16                   pad[3];
+
+        __u64                   prio_bucket[MAX_CACHES_PER_SET];
+
+        union {
+                struct bkey     start[0];
+                __u64           d[0];
+        };
+};
+
+/* Bucket prios/gens */
+
+struct prio_set {
+        __u64                   csum;
+        __u64                   magic;
+        __u64                   seq;
+        __u32                   version;
+        __u32                   pad;
+
+        __u64                   next_bucket;
+
+        struct bucket_disk {
+                __u16           prio;
+                __u8            gen;
+        } __attribute((packed)) data[];
+};
+
+/* UUIDS - per backing device/flash only volume metadata */
+
+struct uuid_entry {
+        union {
+                struct {
+                        __u8    uuid[16];
+                        __u8    label[32];
+                        __u32   first_reg;
+                        __u32   last_reg;
+                        __u32   invalidated;
+
+                        __u32   flags;
+                        /* Size of flash only volumes */
+                        __u64   sectors;
+                };
+
+                __u8            pad[128];
+        };
+};
+
+BITMASK(UUID_FLASH_ONLY,        struct uuid_entry, flags, 0, 1);
+
+/* Btree nodes */
+
+/* Version 1: Seed pointer into btree node checksum
+ */
+#define BCACHE_BSET_CSUM                1
+#define BCACHE_BSET_VERSION             1
+
+/*
+ * Btree nodes
+ *
+ * On disk a btree node is a list/log of these; within each set the keys are
+ * sorted
+ */
+struct bset {
+        __u64                   csum;
+        __u64                   magic;
+        __u64                   seq;
+        __u32                   version;
+        __u32                   keys;
+
+        union {
+                struct bkey     start[0];
+                __u64           d[0];
+        };
+};
+
+/* OBSOLETE */
+
+/* UUIDS - per backing device/flash only volume metadata */
+
+struct uuid_entry_v0 {
+        __u8            uuid[16];
+        __u8            label[32];
+        __u32           first_reg;
+        __u32           last_reg;
+        __u32           invalidated;
+        __u32           pad;
+};
+
+#endif /* _LINUX_BCACHE_H */