ceph: on-wire types

These headers describe the types used to exchange messages between the
Ceph client and various servers.  All types are little-endian and
packed.  These headers are shared between the kernel and userspace, so
all types are in terms of e.g. __u32.

Additionally, we define a few magic values to identify the current
version of the protocol(s) in use, so that discrepancies to be
detected on mount.

Signed-off-by: Sage Weil <sage@newdream.net>

1 files changed, 629 insertions, 0 deletions

diff --git a/fs/ceph/ceph_fs.h b/fs/ceph/ceph_fs.h
new file mode 100644
index 000000000000..21ed51b127f2
--- /dev/null
+++ b/fs/ceph/ceph_fs.h
@@ -0,0 +1,629 @@
+/*
+ * ceph_fs.h - Ceph constants and data types to share between kernel and
+ * user space.
+ *
+ * Most types in this file are defined as little-endian, and are
+ * primarily intended to describe data structures that pass over the
+ * wire or that are stored on disk.
+ *
+ * LGPL2
+ */
+
+#ifndef _FS_CEPH_CEPH_FS_H
+#define _FS_CEPH_CEPH_FS_H
+
+#include "msgr.h"
+#include "rados.h"
+
+/*
+ * Ceph release version
+ */
+#define CEPH_VERSION_MAJOR 0
+#define CEPH_VERSION_MINOR 16
+#define CEPH_VERSION_PATCH 1
+
+#define _CEPH_STRINGIFY(x) #x
+#define CEPH_STRINGIFY(x) _CEPH_STRINGIFY(x)
+#define CEPH_MAKE_VERSION(x, y, z) CEPH_STRINGIFY(x) "." CEPH_STRINGIFY(y) \
+        "." CEPH_STRINGIFY(z)
+#define CEPH_VERSION CEPH_MAKE_VERSION(CEPH_VERSION_MAJOR, \
+                                       CEPH_VERSION_MINOR, CEPH_VERSION_PATCH)
+
+/*
+ * subprotocol versions.  when specific messages types or high-level
+ * protocols change, bump the affected components.  we keep rev
+ * internal cluster protocols separately from the public,
+ * client-facing protocol.
+ */
+#define CEPH_OSD_PROTOCOL     7 /* cluster internal */
+#define CEPH_MDS_PROTOCOL     9 /* cluster internal */
+#define CEPH_MON_PROTOCOL     4 /* cluster internal */
+#define CEPH_OSDC_PROTOCOL   20 /* server/client */
+#define CEPH_MDSC_PROTOCOL   29 /* server/client */
+#define CEPH_MONC_PROTOCOL   14 /* server/client */
+
+
+#define CEPH_INO_ROOT  1
+
+/* arbitrary limit on max # of monitors (cluster of 3 is typical) */
+#define CEPH_MAX_MON   31
+
+
+unsigned int ceph_full_name_hash(const char *name, unsigned int len);
+
+
+/*
+ * ceph_file_layout - describe data layout for a file/inode
+ */
+struct ceph_file_layout {
+        /* file -> object mapping */
+        __le32 fl_stripe_unit;     /* stripe unit, in bytes.  must be multiple
+                                      of page size. */
+        __le32 fl_stripe_count;    /* over this many objects */
+        __le32 fl_object_size;     /* until objects are this big, then move to
+                                      new objects */
+        __le32 fl_cas_hash;        /* 0 = none; 1 = sha256 */
+
+        /* pg -> disk layout */
+        __le32 fl_object_stripe_unit;  /* for per-object parity, if any */
+
+        /* object -> pg layout */
+        __le32 fl_pg_preferred; /* preferred primary for pg (-1 for none) */
+        __le32 fl_pg_pool;      /* namespace, crush ruleset, rep level */
+} __attribute__ ((packed));
+
+
+
+
+/*********************************************
+ * message layer
+ */
+
+/*
+ * message types
+ */
+
+/* misc */
+#define CEPH_MSG_SHUTDOWN               1
+#define CEPH_MSG_PING                   2
+
+/* client <-> monitor */
+#define CEPH_MSG_MON_MAP                4
+#define CEPH_MSG_MON_GET_MAP            5
+#define CEPH_MSG_CLIENT_MOUNT           10
+#define CEPH_MSG_CLIENT_MOUNT_ACK       11
+#define CEPH_MSG_STATFS                 13
+#define CEPH_MSG_STATFS_REPLY           14
+#define CEPH_MSG_MON_SUBSCRIBE          15
+#define CEPH_MSG_MON_SUBSCRIBE_ACK      16
+
+/* client <-> mds */
+#define CEPH_MSG_MDS_GETMAP             20
+#define CEPH_MSG_MDS_MAP                21
+
+#define CEPH_MSG_CLIENT_SESSION         22
+#define CEPH_MSG_CLIENT_RECONNECT       23
+
+#define CEPH_MSG_CLIENT_REQUEST         24
+#define CEPH_MSG_CLIENT_REQUEST_FORWARD 25
+#define CEPH_MSG_CLIENT_REPLY           26
+#define CEPH_MSG_CLIENT_CAPS            0x310
+#define CEPH_MSG_CLIENT_LEASE           0x311
+#define CEPH_MSG_CLIENT_SNAP            0x312
+#define CEPH_MSG_CLIENT_CAPRELEASE      0x313
+
+/* osd */
+#define CEPH_MSG_OSD_GETMAP       40
+#define CEPH_MSG_OSD_MAP          41
+#define CEPH_MSG_OSD_OP           42
+#define CEPH_MSG_OSD_OPREPLY      43
+
+
+struct ceph_mon_statfs {
+        __le64 have_version;
+        struct ceph_fsid fsid;
+        __le64 tid;
+} __attribute__ ((packed));
+
+struct ceph_statfs {
+        __le64 kb, kb_used, kb_avail;
+        __le64 num_objects;
+} __attribute__ ((packed));
+
+struct ceph_mon_statfs_reply {
+        struct ceph_fsid fsid;
+        __le64 tid;
+        __le64 version;
+        struct ceph_statfs st;
+} __attribute__ ((packed));
+
+struct ceph_osd_getmap {
+        __le64 have_version;
+        struct ceph_fsid fsid;
+        __le32 start;
+} __attribute__ ((packed));
+
+struct ceph_mds_getmap {
+        __le64 have_version;
+        struct ceph_fsid fsid;
+} __attribute__ ((packed));
+
+struct ceph_client_mount {
+        __le64 have_version;
+} __attribute__ ((packed));
+
+struct ceph_mon_subscribe_item {
+        __le64 have;
+        __u8 onetime;
+} __attribute__ ((packed));
+
+/*
+ * mds states
+ *   > 0 -> in
+ *  <= 0 -> out
+ */
+#define CEPH_MDS_STATE_DNE          0  /* down, does not exist. */
+#define CEPH_MDS_STATE_STOPPED     -1  /* down, once existed, but no subtrees.
+                                          empty log. */
+#define CEPH_MDS_STATE_BOOT        -4  /* up, boot announcement. */
+#define CEPH_MDS_STATE_STANDBY     -5  /* up, idle.  waiting for assignment. */
+#define CEPH_MDS_STATE_CREATING    -6  /* up, creating MDS instance. */
+#define CEPH_MDS_STATE_STARTING    -7  /* up, starting previously stopped mds */
+#define CEPH_MDS_STATE_STANDBY_REPLAY -8 /* up, tailing active node's journal */
+
+#define CEPH_MDS_STATE_REPLAY       8  /* up, replaying journal. */
+#define CEPH_MDS_STATE_RESOLVE      9  /* up, disambiguating distributed
+                                          operations (import, rename, etc.) */
+#define CEPH_MDS_STATE_RECONNECT    10 /* up, reconnect to clients */
+#define CEPH_MDS_STATE_REJOIN       11 /* up, rejoining distributed cache */
+#define CEPH_MDS_STATE_CLIENTREPLAY 12 /* up, replaying client operations */
+#define CEPH_MDS_STATE_ACTIVE       13 /* up, active */
+#define CEPH_MDS_STATE_STOPPING     14 /* up, but exporting metadata */
+
+extern const char *ceph_mds_state_name(int s);
+
+
+/*
+ * metadata lock types.
+ *  - these are bitmasks.. we can compose them
+ *  - they also define the lock ordering by the MDS
+ *  - a few of these are internal to the mds
+ */
+#define CEPH_LOCK_DN          1
+#define CEPH_LOCK_ISNAP       2
+#define CEPH_LOCK_IVERSION    4     /* mds internal */
+#define CEPH_LOCK_IFILE       8     /* mds internal */
+#define CEPH_LOCK_IAUTH       32
+#define CEPH_LOCK_ILINK       64
+#define CEPH_LOCK_IDFT        128   /* dir frag tree */
+#define CEPH_LOCK_INEST       256   /* mds internal */
+#define CEPH_LOCK_IXATTR      512
+#define CEPH_LOCK_INO         2048  /* immutable inode bits; not a lock */
+
+/* client_session ops */
+enum {
+        CEPH_SESSION_REQUEST_OPEN,
+        CEPH_SESSION_OPEN,
+        CEPH_SESSION_REQUEST_CLOSE,
+        CEPH_SESSION_CLOSE,
+        CEPH_SESSION_REQUEST_RENEWCAPS,
+        CEPH_SESSION_RENEWCAPS,
+        CEPH_SESSION_STALE,
+        CEPH_SESSION_RECALL_STATE,
+};
+
+extern const char *ceph_session_op_name(int op);
+
+struct ceph_mds_session_head {
+        __le32 op;
+        __le64 seq;
+        struct ceph_timespec stamp;
+        __le32 max_caps, max_leases;
+} __attribute__ ((packed));
+
+/* client_request */
+/*
+ * metadata ops.
+ *  & 0x001000 -> write op
+ *  & 0x010000 -> follow symlink (e.g. stat(), not lstat()).
+ &  & 0x100000 -> use weird ino/path trace
+ */
+#define CEPH_MDS_OP_WRITE        0x001000
+enum {
+        CEPH_MDS_OP_LOOKUP     = 0x00100,
+        CEPH_MDS_OP_GETATTR    = 0x00101,
+        CEPH_MDS_OP_LOOKUPHASH = 0x00102,
+        CEPH_MDS_OP_LOOKUPPARENT = 0x00103,
+
+        CEPH_MDS_OP_SETXATTR   = 0x01105,
+        CEPH_MDS_OP_RMXATTR    = 0x01106,
+        CEPH_MDS_OP_SETLAYOUT  = 0x01107,
+        CEPH_MDS_OP_SETATTR    = 0x01108,
+
+        CEPH_MDS_OP_MKNOD      = 0x01201,
+        CEPH_MDS_OP_LINK       = 0x01202,
+        CEPH_MDS_OP_UNLINK     = 0x01203,
+        CEPH_MDS_OP_RENAME     = 0x01204,
+        CEPH_MDS_OP_MKDIR      = 0x01220,
+        CEPH_MDS_OP_RMDIR      = 0x01221,
+        CEPH_MDS_OP_SYMLINK    = 0x01222,
+
+        CEPH_MDS_OP_CREATE     = 0x00301,
+        CEPH_MDS_OP_OPEN       = 0x00302,
+        CEPH_MDS_OP_READDIR    = 0x00305,
+
+        CEPH_MDS_OP_LOOKUPSNAP = 0x00400,
+        CEPH_MDS_OP_MKSNAP     = 0x01400,
+        CEPH_MDS_OP_RMSNAP     = 0x01401,
+        CEPH_MDS_OP_LSSNAP     = 0x00402,
+};
+
+extern const char *ceph_mds_op_name(int op);
+
+
+#define CEPH_SETATTR_MODE   1
+#define CEPH_SETATTR_UID    2
+#define CEPH_SETATTR_GID    4
+#define CEPH_SETATTR_MTIME  8
+#define CEPH_SETATTR_ATIME 16
+#define CEPH_SETATTR_SIZE  32
+#define CEPH_SETATTR_CTIME 64
+
+union ceph_mds_request_args {
+        struct {
+                __le32 mask;                 /* CEPH_CAP_* */
+        } __attribute__ ((packed)) getattr;
+        struct {
+                __le32 mode;
+                __le32 uid;
+                __le32 gid;
+                struct ceph_timespec mtime;
+                struct ceph_timespec atime;
+                __le64 size, old_size;       /* old_size needed by truncate */
+                __le32 mask;                 /* CEPH_SETATTR_* */
+        } __attribute__ ((packed)) setattr;
+        struct {
+                __le32 frag;                 /* which dir fragment */
+                __le32 max_entries;          /* how many dentries to grab */
+        } __attribute__ ((packed)) readdir;
+        struct {
+                __le32 mode;
+                __le32 rdev;
+        } __attribute__ ((packed)) mknod;
+        struct {
+                __le32 mode;
+        } __attribute__ ((packed)) mkdir;
+        struct {
+                __le32 flags;
+                __le32 mode;
+                __le32 stripe_unit;          /* layout for newly created file */
+                __le32 stripe_count;         /* ... */
+                __le32 object_size;
+                __le32 file_replication;
+                __le32 preferred;
+        } __attribute__ ((packed)) open;
+        struct {
+                __le32 flags;
+        } __attribute__ ((packed)) setxattr;
+        struct {
+                struct ceph_file_layout layout;
+        } __attribute__ ((packed)) setlayout;
+} __attribute__ ((packed));
+
+#define CEPH_MDS_FLAG_REPLAY        1  /* this is a replayed op */
+#define CEPH_MDS_FLAG_WANT_DENTRY   2  /* want dentry in reply */
+
+struct ceph_mds_request_head {
+        __le64 tid, oldest_client_tid;
+        __le32 mdsmap_epoch;           /* on client */
+        __le32 flags;                  /* CEPH_MDS_FLAG_* */
+        __u8 num_retry, num_fwd;       /* count retry, fwd attempts */
+        __le16 num_releases;           /* # include cap/lease release records */
+        __le32 op;                     /* mds op code */
+        __le32 caller_uid, caller_gid;
+        __le64 ino;                    /* use this ino for openc, mkdir, mknod,
+                                          etc. (if replaying) */
+        union ceph_mds_request_args args;
+} __attribute__ ((packed));
+
+/* cap/lease release record */
+struct ceph_mds_request_release {
+        __le64 ino, cap_id;            /* ino and unique cap id */
+        __le32 caps, wanted;           /* new issued, wanted */
+        __le32 seq, issue_seq, mseq;
+        __le32 dname_seq;              /* if releasing a dentry lease, a */
+        __le32 dname_len;              /* string follows. */
+} __attribute__ ((packed));
+
+/* client reply */
+struct ceph_mds_reply_head {
+        __le64 tid;
+        __le32 op;
+        __le32 result;
+        __le32 mdsmap_epoch;
+        __u8 safe;                     /* true if committed to disk */
+        __u8 is_dentry, is_target;     /* true if dentry, target inode records
+                                          are included with reply */
+} __attribute__ ((packed));
+
+/* one for each node split */
+struct ceph_frag_tree_split {
+        __le32 frag;                   /* this frag splits... */
+        __le32 by;                     /* ...by this many bits */
+} __attribute__ ((packed));
+
+struct ceph_frag_tree_head {
+        __le32 nsplits;                /* num ceph_frag_tree_split records */
+        struct ceph_frag_tree_split splits[];
+} __attribute__ ((packed));
+
+/* capability issue, for bundling with mds reply */
+struct ceph_mds_reply_cap {
+        __le32 caps, wanted;           /* caps issued, wanted */
+        __le64 cap_id;
+        __le32 seq, mseq;
+        __le64 realm;                  /* snap realm */
+        __u8 flags;                    /* CEPH_CAP_FLAG_* */
+} __attribute__ ((packed));
+
+#define CEPH_CAP_FLAG_AUTH  1          /* cap is issued by auth mds */
+
+/* inode record, for bundling with mds reply */
+struct ceph_mds_reply_inode {
+        __le64 ino;
+        __le64 snapid;
+        __le32 rdev;
+        __le64 version;                /* inode version */
+        __le64 xattr_version;          /* version for xattr blob */
+        struct ceph_mds_reply_cap cap; /* caps issued for this inode */
+        struct ceph_file_layout layout;
+        struct ceph_timespec ctime, mtime, atime;
+        __le32 time_warp_seq;
+        __le64 size, max_size, truncate_size;
+        __le32 truncate_seq;
+        __le32 mode, uid, gid;
+        __le32 nlink;
+        __le64 files, subdirs, rbytes, rfiles, rsubdirs;  /* dir stats */
+        struct ceph_timespec rctime;
+        struct ceph_frag_tree_head fragtree;  /* (must be at end of struct) */
+} __attribute__ ((packed));
+/* followed by frag array, then symlink string, then xattr blob */
+
+/* reply_lease follows dname, and reply_inode */
+struct ceph_mds_reply_lease {
+        __le16 mask;            /* lease type(s) */
+        __le32 duration_ms;     /* lease duration */
+        __le32 seq;
+} __attribute__ ((packed));
+
+struct ceph_mds_reply_dirfrag {
+        __le32 frag;            /* fragment */
+        __le32 auth;            /* auth mds, if this is a delegation point */
+        __le32 ndist;           /* number of mds' this is replicated on */
+        __le32 dist[];
+} __attribute__ ((packed));
+
+/* file access modes */
+#define CEPH_FILE_MODE_PIN        0
+#define CEPH_FILE_MODE_RD         1
+#define CEPH_FILE_MODE_WR         2
+#define CEPH_FILE_MODE_RDWR       3  /* RD | WR */
+#define CEPH_FILE_MODE_LAZY       4  /* lazy io */
+#define CEPH_FILE_MODE_NUM        8  /* bc these are bit fields.. mostly */
+
+int ceph_flags_to_mode(int flags);
+
+
+/* capability bits */
+#define CEPH_CAP_PIN         1  /* no specific capabilities beyond the pin */
+
+/* generic cap bits */
+#define CEPH_CAP_GSHARED     1  /* client can reads */
+#define CEPH_CAP_GEXCL       2  /* client can read and update */
+#define CEPH_CAP_GCACHE      4  /* (file) client can cache reads */
+#define CEPH_CAP_GRD         8  /* (file) client can read */
+#define CEPH_CAP_GWR        16  /* (file) client can write */
+#define CEPH_CAP_GBUFFER    32  /* (file) client can buffer writes */
+#define CEPH_CAP_GWREXTEND  64  /* (file) client can extend EOF */
+#define CEPH_CAP_GLAZYIO   128  /* (file) client can perform lazy io */
+
+/* per-lock shift */
+#define CEPH_CAP_SAUTH      2
+#define CEPH_CAP_SLINK      4
+#define CEPH_CAP_SXATTR     6
+#define CEPH_CAP_SFILE      8   /* goes at the end (uses >2 cap bits) */
+
+#define CEPH_CAP_BITS       16
+
+/* composed values */
+#define CEPH_CAP_AUTH_SHARED  (CEPH_CAP_GSHARED  << CEPH_CAP_SAUTH)
+#define CEPH_CAP_AUTH_EXCL     (CEPH_CAP_GEXCL     << CEPH_CAP_SAUTH)
+#define CEPH_CAP_LINK_SHARED  (CEPH_CAP_GSHARED  << CEPH_CAP_SLINK)
+#define CEPH_CAP_LINK_EXCL     (CEPH_CAP_GEXCL     << CEPH_CAP_SLINK)
+#define CEPH_CAP_XATTR_SHARED (CEPH_CAP_GSHARED  << CEPH_CAP_SXATTR)
+#define CEPH_CAP_XATTR_EXCL    (CEPH_CAP_GEXCL     << CEPH_CAP_SXATTR)
+#define CEPH_CAP_FILE(x)    (x << CEPH_CAP_SFILE)
+#define CEPH_CAP_FILE_SHARED   (CEPH_CAP_GSHARED   << CEPH_CAP_SFILE)
+#define CEPH_CAP_FILE_EXCL     (CEPH_CAP_GEXCL     << CEPH_CAP_SFILE)
+#define CEPH_CAP_FILE_CACHE    (CEPH_CAP_GCACHE    << CEPH_CAP_SFILE)
+#define CEPH_CAP_FILE_RD       (CEPH_CAP_GRD       << CEPH_CAP_SFILE)
+#define CEPH_CAP_FILE_WR       (CEPH_CAP_GWR       << CEPH_CAP_SFILE)
+#define CEPH_CAP_FILE_BUFFER   (CEPH_CAP_GBUFFER   << CEPH_CAP_SFILE)
+#define CEPH_CAP_FILE_WREXTEND (CEPH_CAP_GWREXTEND << CEPH_CAP_SFILE)
+#define CEPH_CAP_FILE_LAZYIO   (CEPH_CAP_GLAZYIO   << CEPH_CAP_SFILE)
+
+/* cap masks (for getattr) */
+#define CEPH_STAT_CAP_INODE    CEPH_CAP_PIN
+#define CEPH_STAT_CAP_TYPE     CEPH_CAP_PIN  /* mode >> 12 */
+#define CEPH_STAT_CAP_SYMLINK  CEPH_CAP_PIN
+#define CEPH_STAT_CAP_UID      CEPH_CAP_AUTH_SHARED
+#define CEPH_STAT_CAP_GID      CEPH_CAP_AUTH_SHARED
+#define CEPH_STAT_CAP_MODE     CEPH_CAP_AUTH_SHARED
+#define CEPH_STAT_CAP_NLINK    CEPH_CAP_LINK_SHARED
+#define CEPH_STAT_CAP_LAYOUT   CEPH_CAP_FILE_SHARED
+#define CEPH_STAT_CAP_MTIME    CEPH_CAP_FILE_SHARED
+#define CEPH_STAT_CAP_SIZE     CEPH_CAP_FILE_SHARED
+#define CEPH_STAT_CAP_ATIME    CEPH_CAP_FILE_SHARED  /* fixme */
+#define CEPH_STAT_CAP_XATTR    CEPH_CAP_XATTR_SHARED
+#define CEPH_STAT_CAP_INODE_ALL (CEPH_CAP_PIN |                 \
+                                 CEPH_CAP_AUTH_SHARED | \
+                                 CEPH_CAP_LINK_SHARED | \
+                                 CEPH_CAP_FILE_SHARED | \
+                                 CEPH_CAP_XATTR_SHARED)
+
+#define CEPH_CAP_ANY_SHARED (CEPH_CAP_AUTH_SHARED |                     \
+                              CEPH_CAP_LINK_SHARED |                    \
+                              CEPH_CAP_XATTR_SHARED |                   \
+                              CEPH_CAP_FILE_SHARED)
+#define CEPH_CAP_ANY_RD   (CEPH_CAP_ANY_SHARED | CEPH_CAP_FILE_RD |     \
+                           CEPH_CAP_FILE_CACHE)
+
+#define CEPH_CAP_ANY_EXCL (CEPH_CAP_AUTH_EXCL |         \
+                           CEPH_CAP_LINK_EXCL |         \
+                           CEPH_CAP_XATTR_EXCL |        \
+                           CEPH_CAP_FILE_EXCL)
+#define CEPH_CAP_ANY_FILE_WR (CEPH_CAP_FILE_WR | CEPH_CAP_FILE_BUFFER | \
+                              CEPH_CAP_FILE_EXCL)
+#define CEPH_CAP_ANY_WR   (CEPH_CAP_ANY_EXCL | CEPH_CAP_ANY_FILE_WR)
+#define CEPH_CAP_ANY      (CEPH_CAP_ANY_RD | CEPH_CAP_ANY_EXCL | \
+                           CEPH_CAP_ANY_FILE_WR | CEPH_CAP_PIN)
+
+#define CEPH_CAP_LOCKS (CEPH_LOCK_IFILE | CEPH_LOCK_IAUTH | CEPH_LOCK_ILINK | \
+                        CEPH_LOCK_IXATTR)
+
+int ceph_caps_for_mode(int mode);
+
+enum {
+        CEPH_CAP_OP_GRANT,         /* mds->client grant */
+        CEPH_CAP_OP_REVOKE,        /* mds->client revoke */
+        CEPH_CAP_OP_TRUNC,         /* mds->client trunc notify */
+        CEPH_CAP_OP_EXPORT,        /* mds has exported the cap */
+        CEPH_CAP_OP_IMPORT,        /* mds has imported the cap */
+        CEPH_CAP_OP_UPDATE,        /* client->mds update */
+        CEPH_CAP_OP_DROP,          /* client->mds drop cap bits */
+        CEPH_CAP_OP_FLUSH,         /* client->mds cap writeback */
+        CEPH_CAP_OP_FLUSH_ACK,     /* mds->client flushed */
+        CEPH_CAP_OP_FLUSHSNAP,     /* client->mds flush snapped metadata */
+        CEPH_CAP_OP_FLUSHSNAP_ACK, /* mds->client flushed snapped metadata */
+        CEPH_CAP_OP_RELEASE,       /* client->mds release (clean) cap */
+        CEPH_CAP_OP_RENEW,         /* client->mds renewal request */
+};
+
+extern const char *ceph_cap_op_name(int op);
+
+/*
+ * caps message, used for capability callbacks, acks, requests, etc.
+ */
+struct ceph_mds_caps {
+        __le32 op;                  /* CEPH_CAP_OP_* */
+        __le64 ino, realm;
+        __le64 cap_id;
+        __le32 seq, issue_seq;
+        __le32 caps, wanted, dirty; /* latest issued/wanted/dirty */
+        __le32 migrate_seq;
+        __le64 snap_follows;
+        __le32 snap_trace_len;
+        __le64 client_tid;          /* for FLUSH(SNAP) -> FLUSH(SNAP)_ACK */
+
+        /* authlock */
+        __le32 uid, gid, mode;
+
+        /* linklock */
+        __le32 nlink;
+
+        /* xattrlock */
+        __le32 xattr_len;
+        __le64 xattr_version;
+
+        /* filelock */
+        __le64 size, max_size, truncate_size;
+        __le32 truncate_seq;
+        struct ceph_timespec mtime, atime, ctime;
+        struct ceph_file_layout layout;
+        __le32 time_warp_seq;
+} __attribute__ ((packed));
+
+/* cap release msg head */
+struct ceph_mds_cap_release {
+        __le32 num;                /* number of cap_items that follow */
+} __attribute__ ((packed));
+
+struct ceph_mds_cap_item {
+        __le64 ino;
+        __le64 cap_id;
+        __le32 migrate_seq, seq;
+} __attribute__ ((packed));
+
+#define CEPH_MDS_LEASE_REVOKE           1  /*    mds  -> client */
+#define CEPH_MDS_LEASE_RELEASE          2  /* client  -> mds    */
+#define CEPH_MDS_LEASE_RENEW            3  /* client <-> mds    */
+#define CEPH_MDS_LEASE_REVOKE_ACK       4  /* client  -> mds    */
+
+extern const char *ceph_lease_op_name(int o);
+
+/* lease msg header */
+struct ceph_mds_lease {
+        __u8 action;            /* CEPH_MDS_LEASE_* */
+        __le16 mask;            /* which lease */
+        __le64 ino;
+        __le64 first, last;     /* snap range */
+        __le32 seq;
+        __le32 duration_ms;     /* duration of renewal */
+} __attribute__ ((packed));
+/* followed by a __le32+string for dname */
+
+/* client reconnect */
+struct ceph_mds_cap_reconnect {
+        __le64 cap_id;
+        __le32 wanted;
+        __le32 issued;
+        __le64 size;
+        struct ceph_timespec mtime, atime;
+        __le64 snaprealm;
+        __le64 pathbase;        /* base ino for our path to this ino */
+} __attribute__ ((packed));
+/* followed by encoded string */
+
+struct ceph_mds_snaprealm_reconnect {
+        __le64 ino;     /* snap realm base */
+        __le64 seq;     /* snap seq for this snap realm */
+        __le64 parent;  /* parent realm */
+} __attribute__ ((packed));
+
+/*
+ * snaps
+ */
+enum {
+        CEPH_SNAP_OP_UPDATE,  /* CREATE or DESTROY */
+        CEPH_SNAP_OP_CREATE,
+        CEPH_SNAP_OP_DESTROY,
+        CEPH_SNAP_OP_SPLIT,
+};
+
+extern const char *ceph_snap_op_name(int o);
+
+/* snap msg header */
+struct ceph_mds_snap_head {
+        __le32 op;                /* CEPH_SNAP_OP_* */
+        __le64 split;             /* ino to split off, if any */
+        __le32 num_split_inos;    /* # inos belonging to new child realm */
+        __le32 num_split_realms;  /* # child realms udner new child realm */
+        __le32 trace_len;         /* size of snap trace blob */
+} __attribute__ ((packed));
+/* followed by split ino list, then split realms, then the trace blob */
+
+/*
+ * encode info about a snaprealm, as viewed by a client
+ */
+struct ceph_mds_snap_realm {
+        __le64 ino;           /* ino */
+        __le64 created;       /* snap: when created */
+        __le64 parent;        /* ino: parent realm */
+        __le64 parent_since;  /* snap: same parent since */
+        __le64 seq;           /* snap: version */
+        __le32 num_snaps;
+        __le32 num_prior_parent_snaps;
+} __attribute__ ((packed));
+/* followed by my snap list, then prior parent snap list */
+
+#endif