/* * 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 17 #define CEPH_VERSION_PATCH 0 #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 5 /* cluster internal */ #define CEPH_OSDC_PROTOCOL 21 /* server/client */ #define CEPH_MDSC_PROTOCOL 29 /* server/client */ #define CEPH_MONC_PROTOCOL 15 /* 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)); #define CEPH_MIN_STRIPE_UNIT 65536 int ceph_file_layout_is_valid(const struct ceph_file_layout *layout); /********************************************* * 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_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_MAP 41 #define CEPH_MSG_OSD_OP 42 #define CEPH_MSG_OSD_OPREPLY 43 struct ceph_mon_request_header { __le64 have_version; __le16 session_mon; __le64 session_mon_tid; } __attribute__ ((packed)); struct ceph_mon_statfs { struct ceph_mon_request_header monhdr; 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 { struct ceph_mon_request_header monhdr; struct ceph_fsid fsid; __le32 start; } __attribute__ ((packed)); struct ceph_mds_getmap { struct ceph_mon_request_header monhdr; struct ceph_fsid fsid; } __attribute__ ((packed)); struct ceph_client_mount { struct ceph_mon_request_header monhdr; } __attribute__ ((packed)); struct ceph_mon_subscribe_item { __le64 have_version; __le64 have; __u8 onetime; } __attribute__ ((packed)); struct ceph_mon_subscribe_ack { __le32 duration; /* seconds */ struct ceph_fsid fsid; } __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