xref: /dragonfly/sys/vfs/hammer/hammer_disk.h (revision 631c21f2)
1 /*
2  * Copyright (c) 2007 The DragonFly Project.  All rights reserved.
3  *
4  * This code is derived from software contributed to The DragonFly Project
5  * by Matthew Dillon <dillon@backplane.com>
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  *
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in
15  *    the documentation and/or other materials provided with the
16  *    distribution.
17  * 3. Neither the name of The DragonFly Project nor the names of its
18  *    contributors may be used to endorse or promote products derived
19  *    from this software without specific, prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
22  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
23  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
24  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
25  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
26  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
27  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
28  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
29  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
30  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
31  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32  * SUCH DAMAGE.
33  */
34 
35 #ifndef VFS_HAMMER_DISK_H_
36 #define VFS_HAMMER_DISK_H_
37 
38 #include <sys/endian.h>
39 #include <sys/types.h>
40 
41 #ifndef _SYS_UUID_H_
42 #include <sys/uuid.h>
43 #endif
44 
45 /*
46  * The structures below represent the on-disk format for a HAMMER
47  * filesystem.  Note that all fields for on-disk structures are naturally
48  * aligned.  HAMMER uses little endian for fields in on-disk structures.
49  * HAMMER doesn't support big endian arch, but is planned.
50  *
51  * Most of HAMMER revolves around the concept of an object identifier.  An
52  * obj_id is a 64 bit quantity which uniquely identifies a filesystem object
53  * FOR THE ENTIRE LIFE OF THE FILESYSTEM.  This uniqueness allows backups
54  * and mirrors to retain varying amounts of filesystem history by removing
55  * any possibility of conflict through identifier reuse.
56  *
57  * A HAMMER filesystem may span multiple volumes.
58  *
59  * A HAMMER filesystem uses a 16K filesystem buffer size.  All filesystem
60  * I/O is done in multiples of 16K.
61  *
62  * 64K X-bufs are used for blocks >= a file's 1MB mark.
63  *
64  * Per-volume storage limit: 52 bits		4096 TB
65  * Per-Zone storage limit: 60 bits		1 MTB
66  * Per-filesystem storage limit: 60 bits	1 MTB
67  */
68 #define HAMMER_BUFSIZE		16384
69 #define HAMMER_XBUFSIZE		65536
70 #define HAMMER_HBUFSIZE		(HAMMER_BUFSIZE / 2)
71 #define HAMMER_XDEMARC		(1024 * 1024)
72 #define HAMMER_BUFMASK		(HAMMER_BUFSIZE - 1)
73 #define HAMMER_XBUFMASK		(HAMMER_XBUFSIZE - 1)
74 
75 #define HAMMER_BUFSIZE64	((uint64_t)HAMMER_BUFSIZE)
76 #define HAMMER_BUFMASK64	((uint64_t)HAMMER_BUFMASK)
77 
78 #define HAMMER_XBUFSIZE64	((uint64_t)HAMMER_XBUFSIZE)
79 #define HAMMER_XBUFMASK64	((uint64_t)HAMMER_XBUFMASK)
80 
81 #define HAMMER_OFF_ZONE_MASK	0xF000000000000000ULL /* zone portion */
82 #define HAMMER_OFF_VOL_MASK	0x0FF0000000000000ULL /* volume portion */
83 #define HAMMER_OFF_SHORT_MASK	0x000FFFFFFFFFFFFFULL /* offset portion */
84 #define HAMMER_OFF_LONG_MASK	0x0FFFFFFFFFFFFFFFULL /* offset portion */
85 
86 #define HAMMER_OFF_BAD		((hammer_off_t)-1)
87 
88 #define HAMMER_BUFSIZE_DOALIGN(offset)				\
89 	(((offset) + HAMMER_BUFMASK) & ~HAMMER_BUFMASK)
90 #define HAMMER_BUFSIZE64_DOALIGN(offset)			\
91 	(((offset) + HAMMER_BUFMASK64) & ~HAMMER_BUFMASK64)
92 
93 #define HAMMER_XBUFSIZE_DOALIGN(offset)				\
94 	(((offset) + HAMMER_XBUFMASK) & ~HAMMER_XBUFMASK)
95 #define HAMMER_XBUFSIZE64_DOALIGN(offset)			\
96 	(((offset) + HAMMER_XBUFMASK64) & ~HAMMER_XBUFMASK64)
97 
98 /*
99  * The current limit of volumes that can make up a HAMMER FS
100  */
101 #define HAMMER_MAX_VOLUMES	256
102 
103 /*
104  * Reserved space for (future) header junk after the volume header.
105  */
106 #define HAMMER_MIN_VOL_JUNK	(HAMMER_BUFSIZE * 16)	/* 256 KB */
107 #define HAMMER_MAX_VOL_JUNK	HAMMER_MIN_VOL_JUNK
108 #define HAMMER_VOL_JUNK_SIZE	HAMMER_MIN_VOL_JUNK
109 
110 /*
111  * Hammer transaction ids are 64 bit unsigned integers and are usually
112  * synchronized with the time of day in nanoseconds.
113  *
114  * Hammer offsets are used for FIFO indexing and embed a cycle counter
115  * and volume number in addition to the offset.  Most offsets are required
116  * to be 16 KB aligned.
117  */
118 typedef uint64_t hammer_tid_t;
119 typedef uint64_t hammer_off_t;
120 typedef uint32_t hammer_crc_t;
121 typedef uuid_t hammer_uuid_t;
122 
123 #define HAMMER_MIN_TID		0ULL			/* unsigned */
124 #define HAMMER_MAX_TID		0xFFFFFFFFFFFFFFFFULL	/* unsigned */
125 #define HAMMER_MIN_KEY		-0x8000000000000000LL	/* signed */
126 #define HAMMER_MAX_KEY		0x7FFFFFFFFFFFFFFFLL	/* signed */
127 #define HAMMER_MIN_OBJID	HAMMER_MIN_KEY		/* signed */
128 #define HAMMER_MAX_OBJID	HAMMER_MAX_KEY		/* signed */
129 #define HAMMER_MIN_RECTYPE	0x0U			/* unsigned */
130 #define HAMMER_MAX_RECTYPE	0xFFFFU			/* unsigned */
131 #define HAMMER_MIN_OFFSET	0ULL			/* unsigned */
132 #define HAMMER_MAX_OFFSET	0xFFFFFFFFFFFFFFFFULL	/* unsigned */
133 
134 /*
135  * hammer_off_t has several different encodings.  Note that not all zones
136  * encode a vol_no.  Zone bits are not a part of filesystem capacity as
137  * the zone bits aren't directly or indirectly mapped to physical volumes.
138  *
139  * In other words, HAMMER's logical filesystem offset consists of 64 bits,
140  * but the filesystem is considered 60 bits filesystem, not 64 bits.
141  * The maximum filesystem capacity is 1EB, not 16EB.
142  *
143  * zone 0:		available, a big-block that contains the offset is unused
144  * zone 1 (z,v,o):	raw volume relative (offset 0 is the volume header)
145  * zone 2 (z,v,o):	raw buffer relative (offset 0 is the first buffer)
146  * zone 3 (z,o):	undo/redo fifo	- fixed zone-2 offset array in volume header
147  * zone 4 (z,v,o):	freemap		- only real blockmap
148  * zone 8 (z,v,o):	B-Tree		- actually zone-2 address
149  * zone 9 (z,v,o):	meta		- actually zone-2 address
150  * zone 10 (z,v,o):	large-data	- actually zone-2 address
151  * zone 11 (z,v,o):	small-data	- actually zone-2 address
152  * zone 15:		unavailable, usually the offset is beyond volume size
153  *
154  * layer1/layer2 direct map:
155  *	     Maximum HAMMER filesystem capacity from volume aspect
156  *	     2^8(max volumes) * 2^52(max volume size) = 2^60 = 1EB (long offset)
157  *	    <------------------------------------------------------------->
158  *	     8bits   52bits (short offset)
159  *	    <------><----------------------------------------------------->
160  *	zzzzvvvvvvvvoooo oooooooooooooooo oooooooooooooooo oooooooooooooooo
161  *	----111111111111 1111112222222222 222222222ooooooo oooooooooooooooo
162  *	    <-----------------><------------------><---------------------->
163  *	     18bits             19bits              23bits
164  *	    <------------------------------------------------------------->
165  *	     2^18(layer1) * 2^19(layer2) * 2^23(big-block) = 2^60 = 1EB
166  *	     Maximum HAMMER filesystem capacity from blockmap aspect
167  *
168  * volume#0 layout
169  *	+-------------------------> offset 0 of a device/partition
170  *	| volume header (1928 bytes)
171  *	| the rest of header junk space (HAMMER_BUFSIZE aligned)
172  *	+-------------------------> vol_bot_beg
173  *	| boot area (HAMMER_BUFSIZE aligned)
174  *	+-------------------------> vol_mem_beg
175  *	| memory log (HAMMER_BUFSIZE aligned)
176  *	+-------------------------> vol_buf_beg (physical offset of zone-2)
177  *	| zone-4 big-block for layer1
178  *	+-------------------------> vol_buf_beg + HAMMER_BIGBLOCK_SIZE
179  *	| zone-4 big-blocks for layer2
180  *	| ... (1 big-block per 4TB space)
181  *	+-------------------------> vol_buf_beg + HAMMER_BIGBLOCK_SIZE * ...
182  *	| zone-3 big-blocks for UNDO/REDO FIFO
183  *	| ... (max 128 big-blocks)
184  *	+-------------------------> vol_buf_beg + HAMMER_BIGBLOCK_SIZE * ...
185  *	| zone-8 big-block for root B-Tree node/etc
186  *	+-------------------------> vol_buf_beg + HAMMER_BIGBLOCK_SIZE * ...
187  *	| zone-9 big-block for root inode/PFS/etc
188  *	+-------------------------> vol_buf_beg + HAMMER_BIGBLOCK_SIZE * ...
189  *	| zone-X big-blocks
190  *	| ... (big-blocks for new zones after newfs_hammer)
191  *	| ...
192  *	| ...
193  *	| ...
194  *	| ...
195  *	+-------------------------> vol_buf_end (HAMMER_BUFSIZE aligned)
196  *	+-------------------------> end of a device/partition
197  *
198  * volume#N layout (0<N<256)
199  *	+-------------------------> offset 0 of a device/partition
200  *	| volume header (1928 bytes)
201  *	| the rest of header junk space (HAMMER_BUFSIZE aligned)
202  *	+-------------------------> vol_bot_beg
203  *	| boot area (HAMMER_BUFSIZE aligned)
204  *	+-------------------------> vol_mem_beg
205  *	| memory log (HAMMER_BUFSIZE aligned)
206  *	+-------------------------> vol_buf_beg (physical offset of zone-2)
207  *	| zone-4 big-blocks for layer2
208  *	| ... (1 big-block per 4TB space)
209  *	+-------------------------> vol_buf_beg + HAMMER_BIGBLOCK_SIZE * ...
210  *	| zone-X big-blocks
211  *	| ... (unused until volume#(N-1) runs out of space)
212  *	| ...
213  *	| ...
214  *	| ...
215  *	| ...
216  *	+-------------------------> vol_buf_end (HAMMER_BUFSIZE aligned)
217  *	+-------------------------> end of a device/partition
218  */
219 
220 #define HAMMER_ZONE_RAW_VOLUME		0x1000000000000000ULL
221 #define HAMMER_ZONE_RAW_BUFFER		0x2000000000000000ULL
222 #define HAMMER_ZONE_UNDO		0x3000000000000000ULL
223 #define HAMMER_ZONE_FREEMAP		0x4000000000000000ULL
224 #define HAMMER_ZONE_RESERVED05		0x5000000000000000ULL  /* not used */
225 #define HAMMER_ZONE_RESERVED06		0x6000000000000000ULL  /* not used */
226 #define HAMMER_ZONE_RESERVED07		0x7000000000000000ULL  /* not used */
227 #define HAMMER_ZONE_BTREE		0x8000000000000000ULL
228 #define HAMMER_ZONE_META		0x9000000000000000ULL
229 #define HAMMER_ZONE_LARGE_DATA		0xA000000000000000ULL
230 #define HAMMER_ZONE_SMALL_DATA		0xB000000000000000ULL
231 #define HAMMER_ZONE_RESERVED0C		0xC000000000000000ULL  /* not used */
232 #define HAMMER_ZONE_RESERVED0D		0xD000000000000000ULL  /* not used */
233 #define HAMMER_ZONE_RESERVED0E		0xE000000000000000ULL  /* not used */
234 #define HAMMER_ZONE_UNAVAIL		0xF000000000000000ULL
235 
236 #define HAMMER_ZONE_RAW_VOLUME_INDEX	1
237 #define HAMMER_ZONE_RAW_BUFFER_INDEX	2
238 #define HAMMER_ZONE_UNDO_INDEX		3
239 #define HAMMER_ZONE_FREEMAP_INDEX	4
240 #define HAMMER_ZONE_BTREE_INDEX		8
241 #define HAMMER_ZONE_META_INDEX		9
242 #define HAMMER_ZONE_LARGE_DATA_INDEX	10
243 #define HAMMER_ZONE_SMALL_DATA_INDEX	11
244 #define HAMMER_ZONE_UNAVAIL_INDEX	15
245 
246 #define HAMMER_MAX_ZONES		16
247 
248 #define HAMMER_ZONE(offset)		((offset) & HAMMER_OFF_ZONE_MASK)
249 
250 #define hammer_is_zone_raw_volume(offset)		\
251 	(HAMMER_ZONE(offset) == HAMMER_ZONE_RAW_VOLUME)
252 #define hammer_is_zone_raw_buffer(offset)		\
253 	(HAMMER_ZONE(offset) == HAMMER_ZONE_RAW_BUFFER)
254 #define hammer_is_zone_undo(offset)			\
255 	(HAMMER_ZONE(offset) == HAMMER_ZONE_UNDO)
256 #define hammer_is_zone_freemap(offset)			\
257 	(HAMMER_ZONE(offset) == HAMMER_ZONE_FREEMAP)
258 #define hammer_is_zone_btree(offset)			\
259 	(HAMMER_ZONE(offset) == HAMMER_ZONE_BTREE)
260 #define hammer_is_zone_meta(offset)			\
261 	(HAMMER_ZONE(offset) == HAMMER_ZONE_META)
262 #define hammer_is_zone_large_data(offset)		\
263 	(HAMMER_ZONE(offset) == HAMMER_ZONE_LARGE_DATA)
264 #define hammer_is_zone_small_data(offset)		\
265 	(HAMMER_ZONE(offset) == HAMMER_ZONE_SMALL_DATA)
266 #define hammer_is_zone_unavail(offset)			\
267 	(HAMMER_ZONE(offset) == HAMMER_ZONE_UNAVAIL)
268 #define hammer_is_zone_data(offset)			\
269 	(hammer_is_zone_large_data(offset) || hammer_is_zone_small_data(offset))
270 
271 #define hammer_is_index_record(zone)			\
272 	((zone) >= HAMMER_ZONE_BTREE_INDEX &&		\
273 	 (zone) < HAMMER_MAX_ZONES)
274 
275 #define hammer_is_zone_record(offset)			\
276 	hammer_is_index_record(HAMMER_ZONE_DECODE(offset))
277 
278 #define hammer_is_index_direct_xlated(zone)		\
279 	(((zone) == HAMMER_ZONE_RAW_BUFFER_INDEX) ||	\
280 	 ((zone) == HAMMER_ZONE_FREEMAP_INDEX) ||	\
281 	 hammer_is_index_record(zone))
282 
283 #define hammer_is_zone_direct_xlated(offset)		\
284 	hammer_is_index_direct_xlated(HAMMER_ZONE_DECODE(offset))
285 
286 #define HAMMER_ZONE_ENCODE(zone, ham_off)		\
287 	(((hammer_off_t)(zone) << 60) | (ham_off))
288 #define HAMMER_ZONE_DECODE(ham_off)			\
289 	((int)(((hammer_off_t)(ham_off) >> 60)))
290 
291 #define HAMMER_VOL_ENCODE(vol_no)			\
292 	((hammer_off_t)((vol_no) & 255) << 52)
293 #define HAMMER_VOL_DECODE(ham_off)			\
294 	((int)(((hammer_off_t)(ham_off) >> 52) & 255))
295 
296 #define HAMMER_OFF_SHORT_ENCODE(offset)			\
297 	((hammer_off_t)(offset) & HAMMER_OFF_SHORT_MASK)
298 #define HAMMER_OFF_LONG_ENCODE(offset)			\
299 	((hammer_off_t)(offset) & HAMMER_OFF_LONG_MASK)
300 
301 #define HAMMER_ENCODE(zone, vol_no, offset)		\
302 	(((hammer_off_t)(zone) << 60) |			\
303 	HAMMER_VOL_ENCODE(vol_no) |			\
304 	HAMMER_OFF_SHORT_ENCODE(offset))
305 #define HAMMER_ENCODE_RAW_VOLUME(vol_no, offset)	\
306 	HAMMER_ENCODE(HAMMER_ZONE_RAW_VOLUME_INDEX, vol_no, offset)
307 #define HAMMER_ENCODE_RAW_BUFFER(vol_no, offset)	\
308 	HAMMER_ENCODE(HAMMER_ZONE_RAW_BUFFER_INDEX, vol_no, offset)
309 #define HAMMER_ENCODE_UNDO(offset)			\
310 	HAMMER_ENCODE(HAMMER_ZONE_UNDO_INDEX, HAMMER_ROOT_VOLNO, offset)
311 #define HAMMER_ENCODE_FREEMAP(vol_no, offset)		\
312 	HAMMER_ENCODE(HAMMER_ZONE_FREEMAP_INDEX, vol_no, offset)
313 
314 /*
315  * Translate a zone address to zone-X address.
316  */
317 #define hammer_xlate_to_zoneX(zone, offset)		\
318 	HAMMER_ZONE_ENCODE((zone), (offset) & ~HAMMER_OFF_ZONE_MASK)
319 #define hammer_xlate_to_zone2(offset)			\
320 	hammer_xlate_to_zoneX(HAMMER_ZONE_RAW_BUFFER_INDEX, (offset))
321 
322 #define hammer_data_zone(data_len)			\
323 	(((data_len) >= HAMMER_BUFSIZE) ?		\
324 	 HAMMER_ZONE_LARGE_DATA :			\
325 	 HAMMER_ZONE_SMALL_DATA)
326 #define hammer_data_zone_index(data_len)		\
327 	(((data_len) >= HAMMER_BUFSIZE) ?		\
328 	 HAMMER_ZONE_LARGE_DATA_INDEX :			\
329 	 HAMMER_ZONE_SMALL_DATA_INDEX)
330 
331 /*
332  * Big-Block backing store
333  *
334  * A blockmap is a two-level map which translates a blockmap-backed zone
335  * offset into a raw zone 2 offset.  The layer 1 handles 18 bits and the
336  * layer 2 handles 19 bits.  The 8M big-block size is 23 bits so two
337  * layers gives us 18+19+23 = 60 bits of address space.
338  *
339  * When using hinting for a blockmap lookup, the hint is lost when the
340  * scan leaves the HINTBLOCK, which is typically several BIGBLOCK's.
341  * HINTBLOCK is a heuristic.
342  */
343 #define HAMMER_HINTBLOCK_SIZE		(HAMMER_BIGBLOCK_SIZE * 4)
344 #define HAMMER_HINTBLOCK_MASK64		((uint64_t)HAMMER_HINTBLOCK_SIZE - 1)
345 #define HAMMER_BIGBLOCK_SIZE		(8192 * 1024)
346 #define HAMMER_BIGBLOCK_SIZE64		((uint64_t)HAMMER_BIGBLOCK_SIZE)
347 #define HAMMER_BIGBLOCK_MASK		(HAMMER_BIGBLOCK_SIZE - 1)
348 #define HAMMER_BIGBLOCK_MASK64		((uint64_t)HAMMER_BIGBLOCK_SIZE - 1)
349 #define HAMMER_BIGBLOCK_BITS		23
350 #if 0
351 #define HAMMER_BIGBLOCK_OVERFILL	(6144 * 1024)
352 #endif
353 #if (1 << HAMMER_BIGBLOCK_BITS) != HAMMER_BIGBLOCK_SIZE
354 #error "HAMMER_BIGBLOCK_BITS BROKEN"
355 #endif
356 
357 #define HAMMER_BUFFERS_PER_BIGBLOCK			\
358 	(HAMMER_BIGBLOCK_SIZE / HAMMER_BUFSIZE)
359 #define HAMMER_BUFFERS_PER_BIGBLOCK_MASK		\
360 	(HAMMER_BUFFERS_PER_BIGBLOCK - 1)
361 #define HAMMER_BUFFERS_PER_BIGBLOCK_MASK64		\
362 	((hammer_off_t)HAMMER_BUFFERS_PER_BIGBLOCK_MASK)
363 
364 #define HAMMER_BIGBLOCK_DOALIGN(offset)				\
365 	(((offset) + HAMMER_BIGBLOCK_MASK64) & ~HAMMER_BIGBLOCK_MASK64)
366 
367 /*
368  * Maximum number of mirrors operating in master mode (multi-master
369  * clustering and mirroring). Note that HAMMER1 does not support
370  * multi-master clustering as of 2015.
371  */
372 #define HAMMER_MAX_MASTERS		16
373 
374 /*
375  * The blockmap is somewhat of a degenerate structure.  HAMMER only actually
376  * uses it in its original incarnation to implement the freemap.
377  *
378  * zone:1	raw volume (no blockmap)
379  * zone:2	raw buffer (no blockmap)
380  * zone:3	undomap    (direct layer2 array in volume header)
381  * zone:4	freemap    (the only real blockmap)
382  * zone:8-15	zone id used to classify big-block only, address is actually
383  *		a zone-2 address.
384  */
385 typedef struct hammer_blockmap {
386 	hammer_off_t	phys_offset;  /* zone-2 offset only used by zone-4 */
387 	hammer_off_t	first_offset; /* zone-X offset only used by zone-3 */
388 	hammer_off_t	next_offset;  /* zone-X offset for allocation */
389 	hammer_off_t	alloc_offset; /* zone-X offset only used by zone-3 */
390 	uint32_t	reserved01;
391 	hammer_crc_t	entry_crc;
392 } *hammer_blockmap_t;
393 
394 #define HAMMER_BLOCKMAP_CRCSIZE	\
395 	offsetof(struct hammer_blockmap, entry_crc)
396 
397 /*
398  * The blockmap is a 2-layer entity made up of big-blocks.  The first layer
399  * contains 262144 32-byte entries (18 bits), the second layer contains
400  * 524288 16-byte entries (19 bits), representing 8MB (23 bit) blockmaps.
401  * 18+19+23 = 60 bits.  The top four bits are the zone id.
402  *
403  * Currently only the freemap utilizes both layers in all their glory.
404  * All primary data/meta-data zones actually encode a zone-2 address
405  * requiring no real blockmap translation.
406  *
407  * The freemap uses the upper 8 bits of layer-1 to identify the volume,
408  * thus any space allocated via the freemap can be directly translated
409  * to a zone:2 (or zone:8-15) address.
410  *
411  * zone-X blockmap offset: [zone:4][layer1:18][layer2:19][big-block:23]
412  */
413 
414 /*
415  * 32 bytes layer1 entry for 8MB big-block.
416  * A big-block can hold 2^23 / 2^5 = 2^18 layer1 entries,
417  * which equals bits assigned for layer1 in zone-2 address.
418  */
419 typedef struct hammer_blockmap_layer1 {
420 	hammer_off_t	blocks_free;	/* big-blocks free */
421 	hammer_off_t	phys_offset;	/* UNAVAIL or zone-2 */
422 	hammer_off_t	reserved01;
423 	hammer_crc_t	layer2_crc;	/* xor'd crc's of HAMMER_BLOCKSIZE */
424 					/* (not yet used) */
425 	hammer_crc_t	layer1_crc;	/* MUST BE LAST FIELD OF STRUCTURE*/
426 } *hammer_blockmap_layer1_t;
427 
428 #define HAMMER_LAYER1_CRCSIZE	\
429 	offsetof(struct hammer_blockmap_layer1, layer1_crc)
430 
431 /*
432  * 16 bytes layer2 entry for 8MB big-blocks.
433  * A big-block can hold 2^23 / 2^4 = 2^19 layer2 entries,
434  * which equals bits assigned for layer2 in zone-2 address.
435  *
436  * NOTE: bytes_free is signed and can legally go negative if/when data
437  *	 de-dup occurs.  This field will never go higher than
438  *	 HAMMER_BIGBLOCK_SIZE.  If exactly HAMMER_BIGBLOCK_SIZE
439  *	 the big-block is completely free.
440  */
441 typedef struct hammer_blockmap_layer2 {
442 	uint8_t		zone;		/* typed allocation zone */
443 	uint8_t		reserved01;
444 	uint16_t	reserved02;
445 	uint32_t	append_off;	/* allocatable space index */
446 	int32_t		bytes_free;	/* bytes free within this big-block */
447 	hammer_crc_t	entry_crc;
448 } *hammer_blockmap_layer2_t;
449 
450 #define HAMMER_LAYER2_CRCSIZE	\
451 	offsetof(struct hammer_blockmap_layer2, entry_crc)
452 
453 #define HAMMER_BLOCKMAP_UNAVAIL	((hammer_off_t)-1LL)
454 
455 #define HAMMER_BLOCKMAP_RADIX1	/* 2^18 = 262144 */	\
456 	((int)(HAMMER_BIGBLOCK_SIZE / sizeof(struct hammer_blockmap_layer1)))
457 #define HAMMER_BLOCKMAP_RADIX2	/* 2^19 = 524288 */	\
458 	((int)(HAMMER_BIGBLOCK_SIZE / sizeof(struct hammer_blockmap_layer2)))
459 
460 #define HAMMER_BLOCKMAP_LAYER1	/* 2^(18+19+23) = 1EB */	\
461 	(HAMMER_BLOCKMAP_RADIX1 * HAMMER_BLOCKMAP_LAYER2)
462 #define HAMMER_BLOCKMAP_LAYER2	/* 2^(19+23) = 4TB */		\
463 	(HAMMER_BLOCKMAP_RADIX2 * HAMMER_BIGBLOCK_SIZE64)
464 
465 #define HAMMER_BLOCKMAP_LAYER1_MASK	(HAMMER_BLOCKMAP_LAYER1 - 1)
466 #define HAMMER_BLOCKMAP_LAYER2_MASK	(HAMMER_BLOCKMAP_LAYER2 - 1)
467 
468 #define HAMMER_BLOCKMAP_LAYER2_DOALIGN(offset)			\
469 	(((offset) + HAMMER_BLOCKMAP_LAYER2_MASK) &		\
470 	 ~HAMMER_BLOCKMAP_LAYER2_MASK)
471 
472 /*
473  * Index within layer1 or layer2 big-block for the entry representing
474  * a zone-2 physical offset.
475  */
476 #define HAMMER_BLOCKMAP_LAYER1_INDEX(zone2_offset)		\
477 	((int)(((zone2_offset) & HAMMER_BLOCKMAP_LAYER1_MASK) /	\
478 	 HAMMER_BLOCKMAP_LAYER2))
479 
480 #define HAMMER_BLOCKMAP_LAYER2_INDEX(zone2_offset)		\
481 	((int)(((zone2_offset) & HAMMER_BLOCKMAP_LAYER2_MASK) /	\
482 	HAMMER_BIGBLOCK_SIZE64))
483 
484 /*
485  * Byte offset within layer1 or layer2 big-block for the entry representing
486  * a zone-2 physical offset.  Multiply the index by sizeof(blockmap_layer).
487  */
488 #define HAMMER_BLOCKMAP_LAYER1_OFFSET(zone2_offset)		\
489 	(HAMMER_BLOCKMAP_LAYER1_INDEX(zone2_offset) *		\
490 	 sizeof(struct hammer_blockmap_layer1))
491 
492 #define HAMMER_BLOCKMAP_LAYER2_OFFSET(zone2_offset)		\
493 	(HAMMER_BLOCKMAP_LAYER2_INDEX(zone2_offset) *		\
494 	 sizeof(struct hammer_blockmap_layer2))
495 
496 /*
497  * Move on to offset 0 of the next layer1 or layer2.
498  */
499 #define HAMMER_ZONE_LAYER1_NEXT_OFFSET(offset)			\
500 	(((offset) + HAMMER_BLOCKMAP_LAYER2) & ~HAMMER_BLOCKMAP_LAYER2_MASK)
501 
502 #define HAMMER_ZONE_LAYER2_NEXT_OFFSET(offset)			\
503 	(((offset) + HAMMER_BIGBLOCK_SIZE) & ~HAMMER_BIGBLOCK_MASK64)
504 
505 /*
506  * HAMMER UNDO parameters.  The UNDO fifo is mapped directly in the volume
507  * header with an array of zone-2 offsets.  A maximum of (128x8MB) = 1GB,
508  * and minimum of (64x8MB) = 512MB may be reserved.  The size of the undo
509  * fifo is usually set a newfs time.
510  */
511 #define HAMMER_MIN_UNDO_BIGBLOCKS		64
512 #define HAMMER_MAX_UNDO_BIGBLOCKS		128
513 
514 /*
515  * All on-disk HAMMER structures which make up elements of the UNDO FIFO
516  * contain a hammer_fifo_head and hammer_fifo_tail structure.  This structure
517  * contains all the information required to validate the fifo element
518  * and to scan the fifo in either direction.  The head is typically embedded
519  * in higher level hammer on-disk structures while the tail is typically
520  * out-of-band.  hdr_size is the size of the whole mess, including the tail.
521  *
522  * All undo structures are guaranteed to not cross a 16K filesystem
523  * buffer boundary.  Most undo structures are fairly small.  Data spaces
524  * are not immediately reused by HAMMER so file data is not usually recorded
525  * as part of an UNDO.
526  *
527  * PAD elements are allowed to take up only 8 bytes of space as a special
528  * case, containing only hdr_signature, hdr_type, and hdr_size fields,
529  * and with the tail overloaded onto the head structure for 8 bytes total.
530  *
531  * Every undo record has a sequence number.  This number is unrelated to
532  * transaction ids and instead collects the undo transactions associated
533  * with a single atomic operation.  A larger transactional operation, such
534  * as a remove(), may consist of several smaller atomic operations
535  * representing raw meta-data operations.
536  *
537  *				HAMMER VERSION 4 CHANGES
538  *
539  * In HAMMER version 4 the undo structure alignment is reduced from 16384
540  * to 512 bytes in order to ensure that each 512 byte sector begins with
541  * a header.  The hdr_seq field in the header is a 32 bit sequence number
542  * which allows the recovery code to detect missing sectors
543  * without relying on the 32-bit crc and to definitively identify the current
544  * undo sequence space without having to rely on information from the volume
545  * header.  In addition, new REDO entries in the undo space are used to
546  * record write, write/extend, and transaction id updates.
547  *
548  * The grand result is:
549  *
550  * (1) The volume header no longer needs to be synchronized for most
551  *     flush and fsync operations.
552  *
553  * (2) Most fsync operations need only lay down REDO records
554  *
555  * (3) Data overwrite for nohistory operations covered by REDO records
556  *     can be supported (instead of rolling a new block allocation),
557  *     by rolling UNDO for the prior contents of the data.
558  *
559  *				HAMMER VERSION 5 CHANGES
560  *
561  * Hammer version 5 contains a minor adjustment making layer2's bytes_free
562  * field signed, allowing dedup to push it into the negative domain.
563  */
564 #define HAMMER_HEAD_ALIGN		8
565 #define HAMMER_HEAD_ALIGN_MASK		(HAMMER_HEAD_ALIGN - 1)
566 #define HAMMER_HEAD_DOALIGN(bytes)	\
567 	(((bytes) + HAMMER_HEAD_ALIGN_MASK) & ~HAMMER_HEAD_ALIGN_MASK)
568 
569 #define HAMMER_UNDO_ALIGN		512
570 #define HAMMER_UNDO_ALIGN64		((uint64_t)512)
571 #define HAMMER_UNDO_MASK		(HAMMER_UNDO_ALIGN - 1)
572 #define HAMMER_UNDO_MASK64		(HAMMER_UNDO_ALIGN64 - 1)
573 #define HAMMER_UNDO_DOALIGN(offset)	\
574 	(((offset) + HAMMER_UNDO_MASK) & ~HAMMER_UNDO_MASK64)
575 
576 typedef struct hammer_fifo_head {
577 	uint16_t hdr_signature;
578 	uint16_t hdr_type;
579 	uint32_t hdr_size;	/* Aligned size of the whole mess */
580 	uint32_t hdr_seq;	/* Sequence number */
581 	hammer_crc_t hdr_crc;	/* XOR crc up to field w/ crc after field */
582 } *hammer_fifo_head_t;
583 
584 #define HAMMER_FIFO_HEAD_CRCOFF	offsetof(struct hammer_fifo_head, hdr_crc)
585 
586 typedef struct hammer_fifo_tail {
587 	uint16_t tail_signature;
588 	uint16_t tail_type;
589 	uint32_t tail_size;	/* aligned size of the whole mess */
590 } *hammer_fifo_tail_t;
591 
592 /*
593  * Fifo header types.
594  *
595  * NOTE: 0x8000U part of HAMMER_HEAD_TYPE_PAD can be removed if the HAMMER
596  * version ever gets bumped again. It exists only to keep compatibility with
597  * older versions.
598  */
599 #define HAMMER_HEAD_TYPE_PAD	(0x0040U | 0x8000U)
600 #define HAMMER_HEAD_TYPE_DUMMY	0x0041U		/* dummy entry w/seqno */
601 #define HAMMER_HEAD_TYPE_UNDO	0x0043U		/* random UNDO information */
602 #define HAMMER_HEAD_TYPE_REDO	0x0044U		/* data REDO / fast fsync */
603 
604 #define HAMMER_HEAD_SIGNATURE	0xC84EU
605 #define HAMMER_TAIL_SIGNATURE	0xC74FU
606 
607 /*
608  * Misc FIFO structures.
609  *
610  * UNDO - Raw meta-data media updates.
611  */
612 typedef struct hammer_fifo_undo {
613 	struct hammer_fifo_head	head;
614 	hammer_off_t		undo_offset;	/* zone-1,2 offset */
615 	int32_t			undo_data_bytes;
616 	int32_t			undo_reserved01;
617 	/* followed by data */
618 } *hammer_fifo_undo_t;
619 
620 /*
621  * REDO (HAMMER version 4+) - Logical file writes/truncates.
622  *
623  * REDOs contain information which will be duplicated in a later meta-data
624  * update, allowing fast write()+fsync() operations.  REDOs can be ignored
625  * without harming filesystem integrity but must be processed if fsync()
626  * semantics are desired.
627  *
628  * Unlike UNDOs which are processed backwards within the recovery span,
629  * REDOs must be processed forwards starting further back (starting outside
630  * the recovery span).
631  *
632  *	WRITE	- Write logical file (with payload).  Executed both
633  *		  out-of-span and in-span.  Out-of-span WRITEs may be
634  *		  filtered out by TERMs.
635  *
636  *	TRUNC	- Truncate logical file (no payload).  Executed both
637  *		  out-of-span and in-span.  Out-of-span WRITEs may be
638  *		  filtered out by TERMs.
639  *
640  *	TERM_*	- Indicates meta-data was committed (if out-of-span) or
641  *		  will be rolled-back (in-span).  Any out-of-span TERMs
642  *		  matching earlier WRITEs remove those WRITEs from
643  *		  consideration as they might conflict with a later data
644  *		  commit (which is not being rolled-back).
645  *
646  *	SYNC	- The earliest in-span SYNC (the last one when scanning
647  *		  backwards) tells the recovery code how far out-of-span
648  *		  it must go to run REDOs.
649  *
650  * NOTE: WRITEs do not always have matching TERMs even under
651  *	 perfect conditions because truncations might remove the
652  *	 buffers from consideration.  I/O problems can also remove
653  *	 buffers from consideration.
654  *
655  *	 TRUNCSs do not always have matching TERMs because several
656  *	 truncations may be aggregated together into a single TERM.
657  */
658 typedef struct hammer_fifo_redo {
659 	struct hammer_fifo_head	head;
660 	int64_t			redo_objid;	/* file being written */
661 	hammer_off_t		redo_offset;	/* logical offset in file */
662 	int32_t			redo_data_bytes;
663 	uint32_t		redo_flags;
664 	uint32_t		redo_localization;
665 	uint32_t		redo_reserved01;
666 	uint64_t		redo_reserved02;
667 	/* followed by data */
668 } *hammer_fifo_redo_t;
669 
670 #define HAMMER_REDO_WRITE	0x00000001
671 #define HAMMER_REDO_TRUNC	0x00000002
672 #define HAMMER_REDO_TERM_WRITE	0x00000004
673 #define HAMMER_REDO_TERM_TRUNC	0x00000008
674 #define HAMMER_REDO_SYNC	0x00000010
675 
676 typedef union hammer_fifo_any {
677 	struct hammer_fifo_head	head;
678 	struct hammer_fifo_undo	undo;
679 	struct hammer_fifo_redo	redo;
680 } *hammer_fifo_any_t;
681 
682 /*
683  * Volume header types
684  */
685 #define HAMMER_FSBUF_VOLUME	0xC8414D4DC5523031ULL	/* HAMMER01 */
686 #define HAMMER_FSBUF_VOLUME_REV	0x313052C54D4D41C8ULL	/* (reverse endian) */
687 
688 /*
689  * HAMMER Volume header
690  *
691  * A HAMMER filesystem can be built from 1-256 block devices, each block
692  * device contains a volume header followed by however many buffers fit
693  * into the volume.
694  *
695  * One of the volumes making up a HAMMER filesystem is the root volume.
696  * The root volume is always volume #0 which is the first block device path
697  * specified by newfs_hammer(8).  All HAMMER volumes have a volume header,
698  * however the root volume may be the only volume that has valid values for
699  * some fields in the header.
700  *
701  * Special field notes:
702  *
703  *	vol_bot_beg - offset of boot area (mem_beg - bot_beg bytes)
704  *	vol_mem_beg - offset of memory log (buf_beg - mem_beg bytes)
705  *	vol_buf_beg - offset of the first buffer in volume
706  *	vol_buf_end - offset of volume EOF (on buffer boundary)
707  *
708  *	The memory log area allows a kernel to cache new records and data
709  *	in memory without allocating space in the actual filesystem to hold
710  *	the records and data.  In the event that a filesystem becomes full,
711  *	any records remaining in memory can be flushed to the memory log
712  *	area.  This allows the kernel to immediately return success.
713  *
714  *	The buffer offset is a physical offset of zone-2 offset. The lower
715  *	52 bits of the zone-2 offset is added to the buffer offset of each
716  *	volume to generate an actual I/O offset within the block device.
717  *
718  *	NOTE: boot area and memory log are currently not used.
719  */
720 
721 /*
722  * Filesystem type string
723  */
724 #define HAMMER_FSTYPE_STRING		"DragonFly HAMMER"
725 
726 /*
727  * These macros are only used by userspace when userspace commands either
728  * initialize or add a new HAMMER volume.
729  */
730 #define HAMMER_BOOT_MINBYTES		(32*1024)
731 #define HAMMER_BOOT_NOMBYTES		(64LL*1024*1024)
732 #define HAMMER_BOOT_MAXBYTES		(256LL*1024*1024)
733 
734 #define HAMMER_MEM_MINBYTES		(256*1024)
735 #define HAMMER_MEM_NOMBYTES		(1LL*1024*1024*1024)
736 #define HAMMER_MEM_MAXBYTES		(64LL*1024*1024*1024)
737 
738 typedef struct hammer_volume_ondisk {
739 	uint64_t vol_signature;	/* HAMMER_FSBUF_VOLUME for a valid header */
740 
741 	/*
742 	 * These are relative to block device offset, not zone offsets.
743 	 */
744 	int64_t vol_bot_beg;	/* offset of boot area */
745 	int64_t vol_mem_beg;	/* offset of memory log */
746 	int64_t vol_buf_beg;	/* offset of the first buffer in volume */
747 	int64_t vol_buf_end;	/* offset of volume EOF (on buffer boundary) */
748 	int64_t vol_reserved01;
749 
750 	hammer_uuid_t vol_fsid;	/* identify filesystem */
751 	hammer_uuid_t vol_fstype; /* identify filesystem type */
752 	char vol_label[64];	/* filesystem label */
753 
754 	int32_t vol_no;		/* volume number within filesystem */
755 	int32_t vol_count;	/* number of volumes making up filesystem */
756 
757 	uint32_t vol_version;	/* version control information */
758 	hammer_crc_t vol_crc;	/* header crc */
759 	uint32_t vol_flags;	/* volume flags */
760 	uint32_t vol_rootvol;	/* the root volume number (must be 0) */
761 
762 	uint32_t vol_reserved[8];
763 
764 	/*
765 	 * These fields are initialized and space is reserved in every
766 	 * volume making up a HAMMER filesytem, but only the root volume
767 	 * contains valid data.  Note that vol0_stat_bigblocks does not
768 	 * include big-blocks for freemap and undomap initially allocated
769 	 * by newfs_hammer(8).
770 	 */
771 	int64_t vol0_stat_bigblocks;	/* total big-blocks when fs is empty */
772 	int64_t vol0_stat_freebigblocks;/* number of free big-blocks */
773 	int64_t	vol0_reserved01;
774 	int64_t vol0_stat_inodes;	/* for statfs only */
775 	int64_t vol0_reserved02;
776 	hammer_off_t vol0_btree_root;	/* B-Tree root offset in zone-8 */
777 	hammer_tid_t vol0_next_tid;	/* highest partially synchronized TID */
778 	hammer_off_t vol0_reserved03;
779 
780 	/*
781 	 * Blockmaps for zones.  Not all zones use a blockmap.  Note that
782 	 * the entire root blockmap is cached in the hammer_mount structure.
783 	 */
784 	struct hammer_blockmap	vol0_blockmap[HAMMER_MAX_ZONES];
785 
786 	/*
787 	 * Array of zone-2 addresses for undo FIFO.
788 	 */
789 	hammer_off_t		vol0_undo_array[HAMMER_MAX_UNDO_BIGBLOCKS];
790 } *hammer_volume_ondisk_t;
791 
792 #define HAMMER_ROOT_VOLNO		0
793 
794 #define HAMMER_VOLF_NEEDFLUSH		0x0004	/* volume needs flush */
795 
796 #define HAMMER_VOL_CRCSIZE1	\
797 	offsetof(struct hammer_volume_ondisk, vol_crc)
798 #define HAMMER_VOL_CRCSIZE2	\
799 	(sizeof(struct hammer_volume_ondisk) - HAMMER_VOL_CRCSIZE1 -	\
800 	 sizeof(hammer_crc_t))
801 
802 #define HAMMER_VOL_VERSION_MIN		1	/* minimum supported version */
803 #define HAMMER_VOL_VERSION_DEFAULT	7	/* newfs default version */
804 #define HAMMER_VOL_VERSION_WIP		8	/* version >= this is WIP */
805 #define HAMMER_VOL_VERSION_MAX		7	/* maximum supported version */
806 
807 #define HAMMER_VOL_VERSION_ONE		1
808 #define HAMMER_VOL_VERSION_TWO		2	/* new dirent layout (2.3+) */
809 #define HAMMER_VOL_VERSION_THREE	3	/* new snapshot layout (2.5+) */
810 #define HAMMER_VOL_VERSION_FOUR		4	/* new undo/flush (2.5+) */
811 #define HAMMER_VOL_VERSION_FIVE		5	/* dedup (2.9+) */
812 #define HAMMER_VOL_VERSION_SIX		6	/* DIRHASH_ALG1 */
813 #define HAMMER_VOL_VERSION_SEVEN	7	/* use the faster iscsi_crc */
814 
815 /*
816  * Translate a zone-2 address to physical address
817  */
818 #define hammer_xlate_to_phys(volume, zone2_offset)	\
819 	((volume)->vol_buf_beg + HAMMER_OFF_SHORT_ENCODE(zone2_offset))
820 
821 /*
822  * Translate a zone-3 address to zone-2 address
823  */
824 #define HAMMER_UNDO_INDEX(zone3_offset)			\
825 	(HAMMER_OFF_SHORT_ENCODE(zone3_offset) / HAMMER_BIGBLOCK_SIZE)
826 
827 #define hammer_xlate_to_undo(volume, zone3_offset)			\
828 	((volume)->vol0_undo_array[HAMMER_UNDO_INDEX(zone3_offset)] +	\
829 	 (zone3_offset & HAMMER_BIGBLOCK_MASK64))
830 
831 /*
832  * Effective per-volume filesystem capacity including big-blocks for layer1/2
833  */
834 #define HAMMER_VOL_BUF_SIZE(volume)			\
835 	((volume)->vol_buf_end - (volume)->vol_buf_beg)
836 
837 /*
838  * Record types are fairly straightforward.  The B-Tree includes the record
839  * type in its index sort.
840  */
841 #define HAMMER_RECTYPE_UNKNOWN		0x0000
842 #define HAMMER_RECTYPE_INODE		0x0001	/* inode in obj_id space */
843 #define HAMMER_RECTYPE_DATA		0x0010
844 #define HAMMER_RECTYPE_DIRENTRY		0x0011
845 #define HAMMER_RECTYPE_DB		0x0012
846 #define HAMMER_RECTYPE_EXT		0x0013	/* ext attributes */
847 #define HAMMER_RECTYPE_FIX		0x0014	/* fixed attribute */
848 #define HAMMER_RECTYPE_PFS		0x0015	/* PFS management */
849 #define HAMMER_RECTYPE_SNAPSHOT		0x0016	/* Snapshot management */
850 #define HAMMER_RECTYPE_CONFIG		0x0017	/* hammer cleanup config */
851 #define HAMMER_RECTYPE_MAX		0xFFFF
852 
853 #define HAMMER_RECTYPE_ENTRY_START	(HAMMER_RECTYPE_INODE + 1)
854 #define HAMMER_RECTYPE_CLEAN_START	HAMMER_RECTYPE_EXT
855 
856 #define HAMMER_FIXKEY_SYMLINK		1
857 
858 #define HAMMER_OBJTYPE_UNKNOWN		0	/* never exists on-disk as unknown */
859 #define HAMMER_OBJTYPE_DIRECTORY	1
860 #define HAMMER_OBJTYPE_REGFILE		2
861 #define HAMMER_OBJTYPE_DBFILE		3
862 #define HAMMER_OBJTYPE_FIFO		4
863 #define HAMMER_OBJTYPE_CDEV		5
864 #define HAMMER_OBJTYPE_BDEV		6
865 #define HAMMER_OBJTYPE_SOFTLINK		7
866 #define HAMMER_OBJTYPE_PSEUDOFS		8	/* pseudo filesystem obj */
867 #define HAMMER_OBJTYPE_SOCKET		9
868 
869 /*
870  * HAMMER inode attribute data
871  *
872  * The data reference for a HAMMER inode points to this structure.  Any
873  * modifications to the contents of this structure will result in a
874  * replacement operation.
875  *
876  * parent_obj_id is only valid for directories (which cannot be hard-linked),
877  * and specifies the parent directory obj_id.  This field will also be set
878  * for non-directory inodes as a recovery aid, but can wind up holding
879  * stale information.  However, since object id's are not reused, the worse
880  * that happens is that the recovery code is unable to use it.
881  * A parent_obj_id of 0 means it's a root inode of root or non-root PFS.
882  *
883  * NOTE: Future note on directory hardlinks.  We can implement a record type
884  * which allows us to point to multiple parent directories.
885  */
886 typedef struct hammer_inode_data {
887 	uint16_t version;	/* inode data version */
888 	uint16_t mode;		/* basic unix permissions */
889 	uint32_t uflags;	/* chflags */
890 	uint32_t rmajor;	/* used by device nodes */
891 	uint32_t rminor;	/* used by device nodes */
892 	uint64_t ctime;
893 	int64_t parent_obj_id;	/* parent directory obj_id */
894 	hammer_uuid_t uid;
895 	hammer_uuid_t gid;
896 
897 	uint8_t obj_type;
898 	uint8_t cap_flags;	/* capability support flags (extension) */
899 	uint16_t reserved01;
900 	uint32_t reserved02;
901 	uint64_t nlinks;	/* hard links */
902 	uint64_t size;		/* filesystem object size */
903 	union {
904 		char	symlink[24];	/* HAMMER_INODE_BASESYMLEN */
905 	} ext;
906 	uint64_t mtime;	/* mtime must be second-to-last */
907 	uint64_t atime;	/* atime must be last */
908 } *hammer_inode_data_t;
909 
910 /*
911  * Neither mtime nor atime upates are CRCd by the B-Tree element.
912  * mtime updates have UNDO, atime updates do not.
913  */
914 #define HAMMER_INODE_CRCSIZE	\
915 	offsetof(struct hammer_inode_data, mtime)
916 
917 #define HAMMER_INODE_DATA_VERSION	1
918 #define HAMMER_OBJID_ROOT		1	/* root inodes # */
919 #define HAMMER_INODE_BASESYMLEN		24	/* see ext.symlink */
920 
921 /*
922  * Capability & implementation flags.
923  *
924  * HAMMER_INODE_CAP_DIR_LOCAL_INO - Use inode B-Tree localization
925  * for directory entries.  Also see HAMMER_DIR_INODE_LOCALIZATION().
926  */
927 #define HAMMER_INODE_CAP_DIRHASH_MASK	0x03	/* directory: hash algorithm */
928 #define HAMMER_INODE_CAP_DIRHASH_ALG0	0x00
929 #define HAMMER_INODE_CAP_DIRHASH_ALG1	0x01
930 #define HAMMER_INODE_CAP_DIRHASH_ALG2	0x02
931 #define HAMMER_INODE_CAP_DIRHASH_ALG3	0x03
932 #define HAMMER_INODE_CAP_DIR_LOCAL_INO	0x04	/* use inode localization */
933 
934 #define HAMMER_DATA_DOALIGN(offset)				\
935 	(((offset) + 15) & ~15)
936 #define HAMMER_DATA_DOALIGN_WITH(type, offset)			\
937 	(((type)(offset) + 15) & (~(type)15))
938 
939 /*
940  * A HAMMER directory entry associates a HAMMER filesystem object with a
941  * namespace.  It is hooked into a pseudo-filesystem (with its own inode
942  * numbering space) in the filesystem by setting the high 16 bits of the
943  * localization field.  The low 16 bits must be 0 and are reserved for
944  * future use.
945  *
946  * Directory entries are indexed with a 128 bit namekey rather then an
947  * offset.  A portion of the namekey is an iterator/randomizer to deal
948  * with collisions.
949  *
950  * NOTE: leaf.base.obj_type from the related B-Tree leaf entry holds
951  * the filesystem object type of obj_id, e.g. a den_type equivalent.
952  * It is not stored in hammer_direntry_data.
953  *
954  * NOTE: name field / the filename data reference is NOT terminated with \0.
955  */
956 typedef struct hammer_direntry_data {
957 	int64_t obj_id;			/* object being referenced */
958 	uint32_t localization;		/* identify pseudo-filesystem */
959 	uint32_t reserved01;
960 	char	name[16];		/* name (extended) */
961 } *hammer_direntry_data_t;
962 
963 #define HAMMER_ENTRY_NAME_OFF	offsetof(struct hammer_direntry_data, name[0])
964 #define HAMMER_ENTRY_SIZE(nlen)	offsetof(struct hammer_direntry_data, name[nlen])
965 
966 /*
967  * Symlink data which does not fit in the inode is stored in a separate
968  * FIX type record.
969  */
970 typedef struct hammer_symlink_data {
971 	char	name[16];		/* name (extended) */
972 } *hammer_symlink_data_t;
973 
974 #define HAMMER_SYMLINK_NAME_OFF	offsetof(struct hammer_symlink_data, name[0])
975 
976 /*
977  * The root inode for the primary filesystem and root inode for any
978  * pseudo-fs may be tagged with an optional data structure using
979  * HAMMER_RECTYPE_PFS and localization id.  This structure allows
980  * the node to be used as a mirroring master or slave.
981  *
982  * When operating as a slave CD's into the node automatically become read-only
983  * and as-of sync_end_tid.
984  *
985  * When operating as a master the read PFSD info sets sync_end_tid to
986  * the most recently flushed TID.
987  *
988  * sync_low_tid is not yet used but will represent the highest pruning
989  * end-point, after which full history is available.
990  *
991  * We need to pack this structure making it equally sized on both 32-bit and
992  * 64-bit machines as it is part of struct hammer_ioc_mrecord_pfs which is
993  * send over the wire in hammer mirror operations. Only on 64-bit machines
994  * the size of this struct differ when packed or not. This leads us to the
995  * situation where old 64-bit systems (using the non-packed structure),
996  * which were never able to mirror to/from 32-bit systems, are now no longer
997  * able to mirror to/from newer 64-bit systems (using the packed structure).
998  */
999 struct hammer_pseudofs_data {
1000 	hammer_tid_t	sync_low_tid;	/* full history beyond this point */
1001 	hammer_tid_t	sync_beg_tid;	/* earliest tid w/ full history avail */
1002 	hammer_tid_t	sync_end_tid;	/* current synchronizatoin point */
1003 	uint64_t	sync_beg_ts;	/* real-time of last completed sync */
1004 	uint64_t	sync_end_ts;	/* initiation of current sync cycle */
1005 	hammer_uuid_t	shared_uuid;	/* shared uuid (match required) */
1006 	hammer_uuid_t	unique_uuid;	/* unique uuid of this master/slave */
1007 	int32_t		reserved01;	/* reserved for future master_id */
1008 	int32_t		mirror_flags;	/* misc flags */
1009 	char		label[64];	/* filesystem space label */
1010 	char		snapshots[64];	/* softlink dir for pruning */
1011 	int32_t		reserved02;	/* was prune_{time,freq} */
1012 	int32_t		reserved03;	/* was reblock_{time,freq} */
1013 	int32_t		reserved04;	/* was snapshot_freq */
1014 	int32_t		prune_min;	/* do not prune recent history */
1015 	int32_t		prune_max;	/* do not retain history beyond here */
1016 	int32_t		reserved[16];
1017 } __packed;
1018 
1019 typedef struct hammer_pseudofs_data *hammer_pseudofs_data_t;
1020 
1021 #define HAMMER_PFSD_SLAVE	0x00000001
1022 #define HAMMER_PFSD_DELETED	0x80000000
1023 
1024 #define hammer_is_pfs_slave(pfsd)			\
1025 	(((pfsd)->mirror_flags & HAMMER_PFSD_SLAVE) != 0)
1026 #define hammer_is_pfs_master(pfsd)			\
1027 	(!hammer_is_pfs_slave(pfsd))
1028 #define hammer_is_pfs_deleted(pfsd)			\
1029 	(((pfsd)->mirror_flags & HAMMER_PFSD_DELETED) != 0)
1030 
1031 #define HAMMER_MAX_PFS		65536
1032 #define HAMMER_MAX_PFSID	(HAMMER_MAX_PFS - 1)
1033 #define HAMMER_ROOT_PFSID	0
1034 
1035 /*
1036  * Snapshot meta-data { Objid = HAMMER_OBJID_ROOT, Key = tid, rectype = SNAPSHOT }.
1037  *
1038  * Snapshot records replace the old <fs>/snapshots/<softlink> methodology.  Snapshot
1039  * records are mirrored but may be independantly managed once they are laid down on
1040  * a slave.
1041  *
1042  * NOTE: The b-tree key is signed, the tid is not, so callers must still sort the
1043  *	 results.
1044  *
1045  * NOTE: Reserved fields must be zero (as usual)
1046  */
1047 typedef struct hammer_snapshot_data {
1048 	hammer_tid_t	tid;		/* the snapshot TID itself (== key) */
1049 	uint64_t	ts;		/* real-time when snapshot was made */
1050 	uint64_t	reserved01;
1051 	uint64_t	reserved02;
1052 	char		label[64];	/* user-supplied description */
1053 	uint64_t	reserved03[4];
1054 } *hammer_snapshot_data_t;
1055 
1056 /*
1057  * Config meta-data { ObjId = HAMMER_OBJID_ROOT, Key = 0, rectype = CONFIG }.
1058  *
1059  * Used to store the hammer cleanup config.  This data is not mirrored.
1060  */
1061 typedef struct hammer_config_data {
1062 	char		text[1024];
1063 } *hammer_config_data_t;
1064 
1065 /*
1066  * Rollup various structures embedded as record data
1067  */
1068 typedef union hammer_data_ondisk {
1069 	struct hammer_direntry_data entry;
1070 	struct hammer_inode_data inode;
1071 	struct hammer_symlink_data symlink;
1072 	struct hammer_pseudofs_data pfsd;
1073 	struct hammer_snapshot_data snap;
1074 	struct hammer_config_data config;
1075 } *hammer_data_ondisk_t;
1076 
1077 /*
1078  * Ondisk layout of B-Tree related structures
1079  */
1080 #include "hammer_btree.h"
1081 
1082 #define HAMMER_DIR_INODE_LOCALIZATION(ino_data)				\
1083 	(((ino_data)->cap_flags & HAMMER_INODE_CAP_DIR_LOCAL_INO) ?	\
1084 	 HAMMER_LOCALIZE_INODE :					\
1085 	 HAMMER_LOCALIZE_MISC)
1086 
1087 #endif /* !VFS_HAMMER_DISK_H_ */
1088