xref: /dragonfly/sys/vfs/hammer2/hammer2_disk.h (revision 517258aa)
1 /*
2  * Copyright (c) 2011-2012 The DragonFly Project.  All rights reserved.
3  *
4  * This code is derived from software contributed to The DragonFly Project
5  * by Matthew Dillon <dillon@dragonflybsd.org>
6  * by Venkatesh Srinivas <vsrinivas@dragonflybsd.org>
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  *
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  * 2. Redistributions in binary form must reproduce the above copyright
15  *    notice, this list of conditions and the following disclaimer in
16  *    the documentation and/or other materials provided with the
17  *    distribution.
18  * 3. Neither the name of The DragonFly Project nor the names of its
19  *    contributors may be used to endorse or promote products derived
20  *    from this software without specific, prior written permission.
21  *
22  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
23  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
24  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
25  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
26  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
27  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
28  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
29  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
30  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
31  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
32  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33  * SUCH DAMAGE.
34  */
35 #ifndef VFS_HAMMER2_DISK_H_
36 #define VFS_HAMMER2_DISK_H_
37 
38 #ifndef _SYS_UUID_H_
39 #include <sys/uuid.h>
40 #endif
41 #ifndef _SYS_DMSG_H_
42 #include <sys/dmsg.h>
43 #endif
44 
45 /*
46  * The structures below represent the on-disk media structures for the HAMMER2
47  * filesystem.  Note that all fields for on-disk structures are naturally
48  * aligned.  The host endian format is typically used - compatibility is
49  * possible if the implementation detects reversed endian and adjusts accesses
50  * accordingly.
51  *
52  * HAMMER2 primarily revolves around the directory topology:  inodes,
53  * directory entries, and block tables.  Block device buffer cache buffers
54  * are always 64KB.  Logical file buffers are typically 16KB.  All data
55  * references utilize 64-bit byte offsets.
56  *
57  * Free block management is handled independently using blocks reserved by
58  * the media topology.
59  */
60 
61 /*
62  * The data at the end of a file or directory may be a fragment in order
63  * to optimize storage efficiency.  The minimum fragment size is 1KB.
64  * Since allocations are in powers of 2 fragments must also be sized in
65  * powers of 2 (1024, 2048, ... 65536).
66  *
67  * For the moment the maximum allocation size is HAMMER2_PBUFSIZE (64K),
68  * which is 2^16.  Larger extents may be supported in the future.  Smaller
69  * fragments might be supported in the future (down to 64 bytes is possible),
70  * but probably will not be.
71  *
72  * A full indirect block use supports 1024 x 64-byte blockrefs in a 64KB
73  * buffer.  Indirect blocks down to 1KB are supported to keep small
74  * directories small.
75  *
76  * A maximally sized file (2^64-1 bytes) requires 5 indirect block levels.
77  * The hammer2_blockset in the volume header or file inode has another 8
78  * entries, giving us 66+3 = 69 bits of address space.  However, some bits
79  * are taken up by (potentially) requests for redundant copies.  HAMMER2
80  * currently supports up to 8 copies, which brings the address space down
81  * to 66 bits and gives us 2 bits of leeway.
82  */
83 #define HAMMER2_MIN_ALLOC	1024	/* minimum allocation size */
84 #define HAMMER2_MIN_RADIX	10	/* minimum allocation size 2^N */
85 #define HAMMER2_MAX_ALLOC	65536	/* maximum allocation size */
86 #define HAMMER2_MAX_RADIX	16	/* maximum allocation size 2^N */
87 #define HAMMER2_KEY_RADIX	64	/* number of bits in key */
88 
89 /*
90  * MINALLOCSIZE		- The minimum allocation size.  This can be smaller
91  *		  	  or larger than the minimum physical IO size.
92  *
93  *			  NOTE: Should not be larger than 1K since inodes
94  *				are 1K.
95  *
96  * MINIOSIZE		- The minimum IO size.  This must be less than
97  *			  or equal to HAMMER2_LBUFSIZE.
98  *
99  * HAMMER2_LBUFSIZE	- Nominal buffer size for I/O rollups.
100  *
101  * HAMMER2_PBUFSIZE	- Topological block size used by files for all
102  *			  blocks except the block straddling EOF.
103  *
104  * HAMMER2_SEGSIZE	- Allocation map segment size, typically 2MB
105  *			  (space represented by a level0 bitmap).
106  */
107 
108 #define HAMMER2_SEGSIZE		(1 << HAMMER2_FREEMAP_LEVEL0_RADIX)
109 
110 #define HAMMER2_PBUFRADIX	16	/* physical buf (1<<16) bytes */
111 #define HAMMER2_PBUFSIZE	65536
112 #define HAMMER2_LBUFRADIX	14	/* logical buf (1<<14) bytes */
113 #define HAMMER2_LBUFSIZE	16384
114 
115 /*
116  * Generally speaking we want to use 16K and 64K I/Os
117  */
118 #define HAMMER2_MINIORADIX	HAMMER2_LBUFRADIX
119 #define HAMMER2_MINIOSIZE	HAMMER2_LBUFSIZE
120 
121 #define HAMMER2_IND_BYTES_MIN	HAMMER2_LBUFSIZE
122 #define HAMMER2_IND_BYTES_MAX	HAMMER2_PBUFSIZE
123 #define HAMMER2_IND_COUNT_MIN	(HAMMER2_IND_BYTES_MIN / \
124 				 sizeof(hammer2_blockref_t))
125 #define HAMMER2_IND_COUNT_MAX	(HAMMER2_IND_BYTES_MAX / \
126 				 sizeof(hammer2_blockref_t))
127 
128 /*
129  * In HAMMER2, arrays of blockrefs are fully set-associative, meaning that
130  * any element can occur at any index and holes can be anywhere.  As a
131  * future optimization we will be able to flag that such arrays are sorted
132  * and thus optimize lookups, but for now we don't.
133  *
134  * Inodes embed either 512 bytes of direct data or an array of 8 blockrefs,
135  * resulting in highly efficient storage for files <= 512 bytes and for files
136  * <= 512KB.  Up to 8 directory entries can be referenced from a directory
137  * without requiring an indirect block.
138  *
139  * Indirect blocks are typically either 4KB (64 blockrefs / ~4MB represented),
140  * or 64KB (1024 blockrefs / ~64MB represented).
141  */
142 #define HAMMER2_SET_COUNT		8	/* direct entries */
143 #define HAMMER2_SET_RADIX		3
144 #define HAMMER2_EMBEDDED_BYTES		512	/* inode blockset/dd size */
145 #define HAMMER2_EMBEDDED_RADIX		9
146 
147 #define HAMMER2_PBUFMASK	(HAMMER2_PBUFSIZE - 1)
148 #define HAMMER2_LBUFMASK	(HAMMER2_LBUFSIZE - 1)
149 #define HAMMER2_SEGMASK		(HAMMER2_SEGSIZE - 1)
150 
151 #define HAMMER2_LBUFMASK64	((hammer2_off_t)HAMMER2_LBUFMASK)
152 #define HAMMER2_PBUFSIZE64	((hammer2_off_t)HAMMER2_PBUFSIZE)
153 #define HAMMER2_PBUFMASK64	((hammer2_off_t)HAMMER2_PBUFMASK)
154 #define HAMMER2_SEGSIZE64	((hammer2_off_t)HAMMER2_SEGSIZE)
155 #define HAMMER2_SEGMASK64	((hammer2_off_t)HAMMER2_SEGMASK)
156 
157 #define HAMMER2_UUID_STRING	"5cbb9ad1-862d-11dc-a94d-01301bb8a9f5"
158 
159 /*
160  * A HAMMER2 filesystem is always sized in multiples of 8MB.
161  *
162  * A 4MB segment is reserved at the beginning of each 2GB zone.  This segment
163  * contains the volume header (or backup volume header), the free block
164  * table, and possibly other information in the future.
165  *
166  * 4MB = 64 x 64K blocks.  Each 4MB segment is broken down as follows:
167  *
168  *	+-----------------------+
169  *      |	Volume Hdr	| block 0	volume header & alternates
170  *	+-----------------------+		(first four zones only)
171  *	|   FreeBlk Section A   | block 1-8
172  *	+-----------------------+
173  *	|   FreeBlk Section B   | block 9-16
174  *	+-----------------------+
175  *	|   FreeBlk Section C   | block 17-24
176  *	+-----------------------+
177  *	|   FreeBlk Section D   | block 25-32
178  *	+-----------------------+
179  *      |			| block 33...63
180  *      |	reserved	|
181  *      |			|
182  *	+-----------------------+
183  *
184  * The first few 2GB zones contain volume headers and volume header backups.
185  * After that the volume header block# is reserved.
186  *
187  * The freemap utilizes blocks #1-32 for now, see the FREEMAP document.
188  * The Free block table has a resolution of 1KB
189  *
190  * WARNING!  ZONE_SEG and VOLUME_ALIGN must be a multiple of 1<<LEVEL0_RADIX
191  *	     (i.e. a multiple of 2MB).  VOLUME_ALIGN must be >= ZONE_SEG.
192  */
193 #define HAMMER2_VOLUME_ALIGN		(8 * 1024 * 1024)
194 #define HAMMER2_VOLUME_ALIGN64		((hammer2_off_t)HAMMER2_VOLUME_ALIGN)
195 #define HAMMER2_VOLUME_ALIGNMASK	(HAMMER2_VOLUME_ALIGN - 1)
196 #define HAMMER2_VOLUME_ALIGNMASK64     ((hammer2_off_t)HAMMER2_VOLUME_ALIGNMASK)
197 
198 #define HAMMER2_NEWFS_ALIGN		(HAMMER2_VOLUME_ALIGN)
199 #define HAMMER2_NEWFS_ALIGN64		((hammer2_off_t)HAMMER2_VOLUME_ALIGN)
200 #define HAMMER2_NEWFS_ALIGNMASK		(HAMMER2_VOLUME_ALIGN - 1)
201 #define HAMMER2_NEWFS_ALIGNMASK64	((hammer2_off_t)HAMMER2_NEWFS_ALIGNMASK)
202 
203 #define HAMMER2_ZONE_BYTES64		(2LLU * 1024 * 1024 * 1024)
204 #define HAMMER2_ZONE_MASK64		(HAMMER2_ZONE_BYTES64 - 1)
205 #define HAMMER2_ZONE_SEG		(4 * 1024 * 1024)
206 #define HAMMER2_ZONE_SEG64		((hammer2_off_t)HAMMER2_ZONE_SEG)
207 #define HAMMER2_ZONE_BLOCKS_SEG		(HAMMER2_ZONE_SEG / HAMMER2_PBUFSIZE)
208 
209 /*
210  * 64 x 64KB blocks are reserved at the base of each 2GB zone.  These blocks
211  * are used to store the volume header or volume header backups, allocation
212  * tree, and other information in the future.
213  *
214  * All specified blocks are not necessarily used in all 2GB zones.  However,
215  * dead areas are reserved for future use and MUST NOT BE USED for other
216  * purposes.
217  *
218  * The freemap is arranged into four groups.  Modifications rotate through
219  * the groups on a block by block basis (so all the blocks are not necessarily
220  * synchronized to the same group).  Because the freemap is flushed
221  * independent of the main filesystem, the freemap only really needs two
222  * groups to operate efficiently.
223  *
224  *
225  *
226  */
227 #define HAMMER2_ZONE_VOLHDR		0	/* volume header or backup */
228 #define HAMMER2_ZONE_FREEMAP_A		1	/* freemap layer group A */
229 #define HAMMER2_ZONE_FREEMAP_B		9	/* freemap layer group B */
230 #define HAMMER2_ZONE_FREEMAP_C		17	/* freemap layer group C */
231 #define HAMMER2_ZONE_FREEMAP_D		25	/* freemap layer group D */
232 
233 						/* relative to FREEMAP_x */
234 #define HAMMER2_ZONEFM_LEVEL0		0	/* 256KB bitmap (4 blks) */
235 #define HAMMER2_ZONEFM_LEVEL1		4	/* 2GB indmap */
236 #define HAMMER2_ZONEFM_LEVEL2		5	/* 2TB indmap */
237 #define HAMMER2_ZONEFM_LEVEL3		6	/* 2PB indmap */
238 #define HAMMER2_ZONEFM_LEVEL4		7	/* 2EB indmap */
239 /* LEVEL5 is a set of 8 blockrefs in the volume header 16EB */
240 
241 #define HAMMER2_ZONE_BLOCK49		49	/* future */
242 #define HAMMER2_ZONE_BLOCK50		50	/* future */
243 #define HAMMER2_ZONE_BLOCK51		51	/* future */
244 #define HAMMER2_ZONE_BLOCK52		52	/* future */
245 #define HAMMER2_ZONE_BLOCK53		53	/* future */
246 #define HAMMER2_ZONE_BLOCK54		54	/* future */
247 #define HAMMER2_ZONE_BLOCK55		55	/* future */
248 #define HAMMER2_ZONE_BLOCK56		56	/* future */
249 #define HAMMER2_ZONE_BLOCK57		57	/* future */
250 #define HAMMER2_ZONE_BLOCK58		58	/* future */
251 #define HAMMER2_ZONE_BLOCK59		59	/* future */
252 
253 #define HAMMER2_ZONE_BLOCK60		60	/* future */
254 #define HAMMER2_ZONE_BLOCK61		61	/* future */
255 #define HAMMER2_ZONE_BLOCK62		62	/* future */
256 #define HAMMER2_ZONE_BLOCK63		63	/* future */
257 
258 /*
259  * Freemap radii.  Please note that LEVEL 1 blockref array entries
260  * point to 256-byte sections of the bitmap representing 2MB of storage.
261  * Even though the chain structures represent only 256 bytes, they are
262  * mapped using larger 16K or 64K buffer cache buffers.
263  */
264 #define HAMMER2_FREEMAP_LEVEL5_RADIX	64	/* 16EB */
265 #define HAMMER2_FREEMAP_LEVEL4_RADIX	61	/* 2EB */
266 #define HAMMER2_FREEMAP_LEVEL3_RADIX	51	/* 2PB */
267 #define HAMMER2_FREEMAP_LEVEL2_RADIX	41	/* 2TB */
268 #define HAMMER2_FREEMAP_LEVEL1_RADIX	31	/* 2GB (256KB of bitmap) */
269 #define HAMMER2_FREEMAP_LEVEL0_RADIX	21	/* 2MB (256 bytes of bitmap) */
270 
271 #define HAMMER2_FREEMAP_LEVELN_PSIZE	65536	/* physical bytes */
272 #define HAMMER2_FREEMAP_LEVEL0_PSIZE	256	/* physical bytes */
273 
274 
275 /*
276  * Two linear areas can be reserved after the initial 2MB segment in the base
277  * zone (the one starting at offset 0).  These areas are NOT managed by the
278  * block allocator and do not fall under HAMMER2 crc checking rules based
279  * at the volume header (but can be self-CRCd internally, depending).
280  */
281 #define HAMMER2_BOOT_MIN_BYTES		HAMMER2_VOLUME_ALIGN
282 #define HAMMER2_BOOT_NOM_BYTES		(64*1024*1024)
283 #define HAMMER2_BOOT_MAX_BYTES		(256*1024*1024)
284 
285 #define HAMMER2_REDO_MIN_BYTES		HAMMER2_VOLUME_ALIGN
286 #define HAMMER2_REDO_NOM_BYTES		(256*1024*1024)
287 #define HAMMER2_REDO_MAX_BYTES		(1024*1024*1024)
288 
289 /*
290  * Most HAMMER2 types are implemented as unsigned 64-bit integers.
291  * Transaction ids are monotonic.
292  *
293  * We utilize 32-bit iSCSI CRCs.
294  */
295 typedef uint64_t hammer2_tid_t;
296 typedef uint64_t hammer2_off_t;
297 typedef uint64_t hammer2_key_t;
298 typedef uint32_t hammer2_crc32_t;
299 
300 /*
301  * Miscellanious ranges (all are unsigned).
302  */
303 #define HAMMER2_MIN_TID		1ULL
304 #define HAMMER2_MAX_TID		0xFFFFFFFFFFFFFFFFULL
305 #define HAMMER2_MIN_KEY		0ULL
306 #define HAMMER2_MAX_KEY		0xFFFFFFFFFFFFFFFFULL
307 #define HAMMER2_MIN_OFFSET	0ULL
308 #define HAMMER2_MAX_OFFSET	0xFFFFFFFFFFFFFFFFULL
309 
310 /*
311  * HAMMER2 data offset special cases and masking.
312  *
313  * All HAMMER2 data offsets have to be broken down into a 64K buffer base
314  * offset (HAMMER2_OFF_MASK_HI) and a 64K buffer index (HAMMER2_OFF_MASK_LO).
315  *
316  * Indexes into physical buffers are always 64-byte aligned.  The low 6 bits
317  * of the data offset field specifies how large the data chunk being pointed
318  * to as a power of 2.  The theoretical minimum radix is thus 6 (The space
319  * needed in the low bits of the data offset field).  However, the practical
320  * minimum allocation chunk size is 1KB (a radix of 10), so HAMMER2 sets
321  * HAMMER2_MIN_RADIX to 10.  The maximum radix is currently 16 (64KB), but
322  * we fully intend to support larger extents in the future.
323  */
324 #define HAMMER2_OFF_BAD		((hammer2_off_t)-1)
325 #define HAMMER2_OFF_MASK	0xFFFFFFFFFFFFFFC0ULL
326 #define HAMMER2_OFF_MASK_LO	(HAMMER2_OFF_MASK & HAMMER2_PBUFMASK64)
327 #define HAMMER2_OFF_MASK_HI	(~HAMMER2_PBUFMASK64)
328 #define HAMMER2_OFF_MASK_RADIX	0x000000000000003FULL
329 #define HAMMER2_MAX_COPIES	6
330 
331 /*
332  * HAMMER2 directory support and pre-defined keys
333  */
334 #define HAMMER2_DIRHASH_VISIBLE	0x8000000000000000ULL
335 #define HAMMER2_DIRHASH_USERMSK	0x7FFFFFFFFFFFFFFFULL
336 #define HAMMER2_DIRHASH_LOMASK	0x0000000000007FFFULL
337 #define HAMMER2_DIRHASH_HIMASK	0xFFFFFFFFFFFF0000ULL
338 #define HAMMER2_DIRHASH_FORCED	0x0000000000008000ULL	/* bit forced on */
339 
340 #define HAMMER2_SROOT_KEY	0x0000000000000000ULL	/* volume to sroot */
341 
342 /*
343  * The media block reference structure.  This forms the core of the HAMMER2
344  * media topology recursion.  This 64-byte data structure is embedded in the
345  * volume header, in inodes (which are also directory entries), and in
346  * indirect blocks.
347  *
348  * A blockref references a single media item, which typically can be a
349  * directory entry (aka inode), indirect block, or data block.
350  *
351  * The primary feature a blockref represents is the ability to validate
352  * the entire tree underneath it via its check code.  Any modification to
353  * anything propagates up the blockref tree all the way to the root, replacing
354  * the related blocks.  Propagations can shortcut to the volume root to
355  * implement the 'fast syncing' feature but this only delays the eventual
356  * propagation.
357  *
358  * The check code can be a simple 32-bit iscsi code, a 64-bit crc,
359  * or as complex as a 192 bit cryptographic hash.  192 bits is the maximum
360  * supported check code size, which is not sufficient for unverified dedup
361  * UNLESS one doesn't mind once-in-a-blue-moon data corruption (such as when
362  * farming web data).  HAMMER2 has an unverified dedup feature for just this
363  * purpose.
364  *
365  * --
366  *
367  * NOTE: The range of keys represented by the blockref is (key) to
368  *	 ((key) + (1LL << keybits) - 1).  HAMMER2 usually populates
369  *	 blocks bottom-up, inserting a new root when radix expansion
370  *	 is required.
371  */
372 struct hammer2_blockref {		/* MUST BE EXACTLY 64 BYTES */
373 	uint8_t		type;		/* type of underlying item */
374 	uint8_t		methods;	/* check method & compression method */
375 	uint8_t		copyid;		/* specify which copy this is */
376 	uint8_t		keybits;	/* #of keybits masked off 0=leaf */
377 	uint8_t		vradix;		/* virtual data/meta-data size */
378 	uint8_t		flags;		/* blockref flags */
379 	uint8_t		reserved06;
380 	uint8_t		reserved07;
381 	hammer2_key_t	key;		/* key specification */
382 	hammer2_tid_t	mirror_tid;	/* propagate for mirror scan */
383 	hammer2_tid_t	modify_tid;	/* modifications sans propagation */
384 	hammer2_off_t	data_off;	/* low 6 bits is phys size (radix)*/
385 	union {				/* check info */
386 		char	buf[24];
387 		struct {
388 			uint32_t value;
389 			uint32_t unused[5];
390 		} iscsi32;
391 		struct {
392 			uint64_t value;
393 			uint64_t unused[2];
394 		} crc64;
395 		struct {
396 			char data[24];
397 		} sha192;
398 
399 		/*
400 		 * Freemap hints are embedded in addition to the icrc32.
401 		 *
402 		 * biggest - Largest possible allocation 2^N within sub-tree.
403 		 *	     typically initialized to 64 in freemap_blockref
404 		 *	     and reduced as-needed when a request fails.
405 		 *
406 		 *	     An allocation > 2^N is guaranteed to fail.  An
407 		 *	     allocation <= 2^N MAY fail, and if it does the
408 		 *	     biggest hint will be adjusted downward.
409 		 *
410 		 *	     Used when allocating space.
411 		 *
412 		 * radix   - (Leaf only) once assigned, radix for clustering.
413 		 *	     All device I/O can cluster within the 2MB
414 		 *	     segment.
415 		 */
416 		struct {
417 			uint32_t icrc32;
418 			uint8_t biggest;
419 			uint8_t radix;		/* 0, LBUFRADIX, PBUFRADIX */
420 			uint8_t reserved06;
421 			uint8_t reserved07;
422 			uint64_t avail;		/* total available bytes */
423 			uint64_t unused;	/* unused must be 0 */
424 		} freemap;
425 	} check;
426 };
427 
428 typedef struct hammer2_blockref hammer2_blockref_t;
429 
430 #if 0
431 #define HAMMER2_BREF_SYNC1		0x01	/* modification synchronized */
432 #define HAMMER2_BREF_SYNC2		0x02	/* modification committed */
433 #define HAMMER2_BREF_DESYNCCHLD		0x04	/* desynchronize children */
434 #define HAMMER2_BREF_DELETED		0x80	/* indicates a deletion */
435 #endif
436 
437 #define HAMMER2_BLOCKREF_BYTES		64	/* blockref struct in bytes */
438 
439 #define HAMMER2_BREF_TYPE_EMPTY		0
440 #define HAMMER2_BREF_TYPE_INODE		1
441 #define HAMMER2_BREF_TYPE_INDIRECT	2
442 #define HAMMER2_BREF_TYPE_DATA		3
443 #define HAMMER2_BREF_TYPE_UNUSED04	4
444 #define HAMMER2_BREF_TYPE_FREEMAP_NODE	5
445 #define HAMMER2_BREF_TYPE_FREEMAP_LEAF	6
446 #define HAMMER2_BREF_TYPE_FREEMAP	254	/* pseudo-type */
447 #define HAMMER2_BREF_TYPE_VOLUME	255	/* pseudo-type */
448 
449 #define HAMMER2_ENC_CHECK(n)		((n) << 4)
450 #define HAMMER2_DEC_CHECK(n)		(((n) >> 4) & 15)
451 
452 #define HAMMER2_CHECK_NONE		0
453 #define HAMMER2_CHECK_ISCSI32		1
454 #define HAMMER2_CHECK_CRC64		2
455 #define HAMMER2_CHECK_SHA192		3
456 #define HAMMER2_CHECK_FREEMAP		4
457 
458 #define HAMMER2_ENC_COMP(n)		(n)
459 #define HAMMER2_DEC_COMP(n)		((n) & 15)
460 
461 #define HAMMER2_COMP_NONE		0
462 #define HAMMER2_COMP_AUTOZERO		1
463 
464 
465 /*
466  * HAMMER2 block references are collected into sets of 8 blockrefs.  These
467  * sets are fully associative, meaning the elements making up a set are
468  * not sorted in any way and may contain duplicate entries, holes, or
469  * entries which shortcut multiple levels of indirection.  Sets are used
470  * in various ways:
471  *
472  * (1) When redundancy is desired a set may contain several duplicate
473  *     entries pointing to different copies of the same data.  Up to 8 copies
474  *     are supported but the set structure becomes a bit inefficient once
475  *     you go over 4.
476  *
477  * (2) The blockrefs in a set can shortcut multiple levels of indirections
478  *     within the bounds imposed by the parent of set.
479  *
480  * When a set fills up another level of indirection is inserted, moving
481  * some or all of the set's contents into indirect blocks placed under the
482  * set.  This is a top-down approach in that indirect blocks are not created
483  * until the set actually becomes full (that is, the entries in the set can
484  * shortcut the indirect blocks when the set is not full).  Depending on how
485  * things are filled multiple indirect blocks will eventually be created.
486  *
487  * Indirect blocks are typically 4KB (64 entres) or 64KB (1024 entries) and
488  * are also treated as fully set-associative.
489  */
490 struct hammer2_blockset {
491 	hammer2_blockref_t	blockref[HAMMER2_SET_COUNT];
492 };
493 
494 typedef struct hammer2_blockset hammer2_blockset_t;
495 
496 /*
497  * Catch programmer snafus
498  */
499 #if (1 << HAMMER2_SET_RADIX) != HAMMER2_SET_COUNT
500 #error "hammer2 direct radix is incorrect"
501 #endif
502 #if (1 << HAMMER2_PBUFRADIX) != HAMMER2_PBUFSIZE
503 #error "HAMMER2_PBUFRADIX and HAMMER2_PBUFSIZE are inconsistent"
504 #endif
505 #if (1 << HAMMER2_MIN_RADIX) != HAMMER2_MIN_ALLOC
506 #error "HAMMER2_MIN_RADIX and HAMMER2_MIN_ALLOC are inconsistent"
507 #endif
508 
509 /*
510  * The media indirect block structure.
511  */
512 struct hammer2_indblock_data {
513 	hammer2_blockref_t blockref[HAMMER2_IND_COUNT_MAX];
514 };
515 
516 typedef struct hammer2_indblock_data hammer2_indblock_data_t;
517 
518 struct hammer2_bmap_data {
519 	uint64_t    array[HAMMER2_FREEMAP_LEVEL0_PSIZE / sizeof(uint64_t)];
520 };
521 
522 typedef struct hammer2_bmap_data hammer2_bmap_data_t;
523 
524 /*
525  * In HAMMER2 inodes ARE directory entries, with a special exception for
526  * hardlinks.  The inode number is stored in the inode rather than being
527  * based on the location of the inode (since the location moves every time
528  * the inode or anything underneath the inode is modified).
529  *
530  * The inode is 1024 bytes, made up of 256 bytes of meta-data, 256 bytes
531  * for the filename, and 512 bytes worth of direct file data OR an embedded
532  * blockset.
533  *
534  * Directories represent one inode per blockref.  Inodes are not laid out
535  * as a file but instead are represented by the related blockrefs.  The
536  * blockrefs, in turn, are indexed by the 64-bit directory hash key.  Remember
537  * that blocksets are fully associative, so a certain degree efficiency is
538  * achieved just from that.
539  *
540  * Up to 512 bytes of direct data can be embedded in an inode, and since
541  * inodes are essentially directory entries this also means that small data
542  * files end up simply being laid out linearly in the directory, resulting
543  * in fewer seeks and highly optimal access.
544  *
545  * The compression mode can be changed at any time in the inode and is
546  * recorded on a blockref-by-blockref basis.
547  *
548  * Hardlinks are supported via the inode map.  Essentially the way a hardlink
549  * works is that all individual directory entries representing the same file
550  * are special cased and specify the same inode number.  The actual file
551  * is placed in the nearest parent directory that is parent to all instances
552  * of the hardlink.  If all hardlinks to a file are in the same directory
553  * the actual file will also be placed in that directory.  This file uses
554  * the inode number as the directory entry key and is invisible to normal
555  * directory scans.  Real directory entry keys are differentiated from the
556  * inode number key via bit 63.  Access to the hardlink silently looks up
557  * the real file and forwards all operations to that file.  Removal of the
558  * last hardlink also removes the real file.
559  *
560  * (attr_tid) is only updated when the inode's specific attributes or regular
561  * file size has changed, and affects path lookups and stat.  (attr_tid)
562  * represents a special cache coherency lock under the inode.  The inode
563  * blockref's modify_tid will always cover it.
564  *
565  * (dirent_tid) is only updated when an entry under a directory inode has
566  * been created, deleted, renamed, or had its attributes change, and affects
567  * directory lookups and scans.  (dirent_tid) represents another special cache
568  * coherency lock under the inode.  The inode blockref's modify_tid will
569  * always cover it.
570  */
571 #define HAMMER2_INODE_BYTES		1024	/* (asserted by code) */
572 #define HAMMER2_INODE_MAXNAME		256	/* maximum name in bytes */
573 #define HAMMER2_INODE_VERSION_ONE	1
574 
575 struct hammer2_inode_data {
576 	uint16_t	version;	/* 0000 inode data version */
577 	uint16_t	reserved02;	/* 0002 */
578 
579 	/*
580 	 * core inode attributes, inode type, misc flags
581 	 */
582 	uint32_t	uflags;		/* 0004 chflags */
583 	uint32_t	rmajor;		/* 0008 available for device nodes */
584 	uint32_t	rminor;		/* 000C available for device nodes */
585 	uint64_t	ctime;		/* 0010 inode change time */
586 	uint64_t	mtime;		/* 0018 modified time */
587 	uint64_t	atime;		/* 0020 access time (unsupported) */
588 	uint64_t	btime;		/* 0028 birth time */
589 	uuid_t		uid;		/* 0030 uid / degenerate unix uid */
590 	uuid_t		gid;		/* 0040 gid / degenerate unix gid */
591 
592 	uint8_t		type;		/* 0050 object type */
593 	uint8_t		op_flags;	/* 0051 operational flags */
594 	uint16_t	cap_flags;	/* 0052 capability flags */
595 	uint32_t	mode;		/* 0054 unix modes (typ low 16 bits) */
596 
597 	/*
598 	 * inode size, identification, localized recursive configuration
599 	 * for compression and backup copies.
600 	 */
601 	hammer2_tid_t	inum;		/* 0058 inode number */
602 	hammer2_off_t	size;		/* 0060 size of file */
603 	uint64_t	nlinks;		/* 0068 hard links (typ only dirs) */
604 	hammer2_tid_t	iparent;	/* 0070 parent inum (recovery only) */
605 	hammer2_key_t	name_key;	/* 0078 full filename key */
606 	uint16_t	name_len;	/* 0080 filename length */
607 	uint8_t		ncopies;	/* 0082 ncopies to local media */
608 	uint8_t		comp_algo;	/* 0083 compression request & algo */
609 
610 	/*
611 	 * These fields are currently only applicable to PFSROOTs.
612 	 *
613 	 * NOTE: We can't use {volume_data->fsid, pfs_clid} to uniquely
614 	 *	 identify an instance of a PFS in the cluster because
615 	 *	 a mount may contain more than one copy of the PFS as
616 	 *	 a separate node.  {pfs_clid, pfs_fsid} must be used for
617 	 *	 registration in the cluster.
618 	 */
619 	uint8_t		target_type;	/* 0084 hardlink target type */
620 	uint8_t		reserved85;	/* 0085 */
621 	uint8_t		reserved86;	/* 0086 */
622 	uint8_t		pfs_type;	/* 0087 (if PFSROOT) node type */
623 	uint64_t	pfs_inum;	/* 0088 (if PFSROOT) inum allocator */
624 	uuid_t		pfs_clid;	/* 0090 (if PFSROOT) cluster uuid */
625 	uuid_t		pfs_fsid;	/* 00A0 (if PFSROOT) unique uuid */
626 
627 	/*
628 	 * Quotas and cumulative sub-tree counters.
629 	 */
630 	hammer2_off_t	data_quota;	/* 00B0 subtree quota in bytes */
631 	hammer2_off_t	data_count;	/* 00B8 subtree byte count */
632 	hammer2_off_t	inode_quota;	/* 00C0 subtree quota inode count */
633 	hammer2_off_t	inode_count;	/* 00C8 subtree inode count */
634 	hammer2_tid_t	attr_tid;	/* 00D0 attributes changed */
635 	hammer2_tid_t	dirent_tid;	/* 00D8 directory/attr changed */
636 	uint64_t	reservedE0;	/* 00E0 */
637 	uint64_t	reservedE8;	/* 00E8 */
638 	uint64_t	reservedF0;	/* 00F0 */
639 	uint64_t	reservedF8;	/* 00F8 */
640 
641 	unsigned char	filename[HAMMER2_INODE_MAXNAME];
642 					/* 0100-01FF (256 char, unterminated) */
643 	union {				/* 0200-03FF (64x8 = 512 bytes) */
644 		struct hammer2_blockset blockset;
645 		char data[HAMMER2_EMBEDDED_BYTES];
646 	} u;
647 };
648 
649 typedef struct hammer2_inode_data hammer2_inode_data_t;
650 
651 #define HAMMER2_OPFLAG_DIRECTDATA	0x01
652 #define HAMMER2_OPFLAG_PFSROOT		0x02
653 #define HAMMER2_OPFLAG_COPYIDS		0x04	/* copyids override parent */
654 
655 #define HAMMER2_OBJTYPE_UNKNOWN		0
656 #define HAMMER2_OBJTYPE_DIRECTORY	1
657 #define HAMMER2_OBJTYPE_REGFILE		2
658 #define HAMMER2_OBJTYPE_FIFO		4
659 #define HAMMER2_OBJTYPE_CDEV		5
660 #define HAMMER2_OBJTYPE_BDEV		6
661 #define HAMMER2_OBJTYPE_SOFTLINK	7
662 #define HAMMER2_OBJTYPE_HARDLINK	8	/* dummy entry for hardlink */
663 #define HAMMER2_OBJTYPE_SOCKET		9
664 #define HAMMER2_OBJTYPE_WHITEOUT	10
665 
666 #define HAMMER2_COPYID_NONE		0
667 #define HAMMER2_COPYID_LOCAL		((uint8_t)-1)
668 
669 /*
670  * PEER types identify connections and help cluster controller filter
671  * out unwanted SPANs.
672  */
673 #define HAMMER2_PEER_NONE		DMSG_PEER_NONE
674 #define HAMMER2_PEER_CLUSTER		DMSG_PEER_CLUSTER
675 #define HAMMER2_PEER_BLOCK		DMSG_PEER_BLOCK
676 #define HAMMER2_PEER_HAMMER2		DMSG_PEER_HAMMER2
677 
678 #define HAMMER2_COPYID_COUNT		DMSG_COPYID_COUNT
679 
680 /*
681  * PFS types identify a PFS on media and in LNK_SPAN messages.
682  */
683 #define HAMMER2_PFSTYPE_NONE		DMSG_PFSTYPE_NONE
684 #define HAMMER2_PFSTYPE_ADMIN		DMSG_PFSTYPE_ADMIN
685 #define HAMMER2_PFSTYPE_CLIENT		DMSG_PFSTYPE_CLIENT
686 #define HAMMER2_PFSTYPE_CACHE		DMSG_PFSTYPE_CACHE
687 #define HAMMER2_PFSTYPE_COPY		DMSG_PFSTYPE_COPY
688 #define HAMMER2_PFSTYPE_SLAVE		DMSG_PFSTYPE_SLAVE
689 #define HAMMER2_PFSTYPE_SOFT_SLAVE	DMSG_PFSTYPE_SOFT_SLAVE
690 #define HAMMER2_PFSTYPE_SOFT_MASTER	DMSG_PFSTYPE_SOFT_MASTER
691 #define HAMMER2_PFSTYPE_MASTER		DMSG_PFSTYPE_MASTER
692 #define HAMMER2_PFSTYPE_SNAPSHOT	DMSG_PFSTYPE_SNAPSHOT
693 #define HAMMER2_PFSTYPE_MAX		DMSG_PFSTYPE_MAX
694 
695 /*
696  *				Allocation Table
697  *
698  */
699 
700 
701 /*
702  * Flags (8 bits) - blockref, for freemap only
703  *
704  * Note that the minimum chunk size is 1KB so we could theoretically have
705  * 10 bits here, but we might have some future extension that allows a
706  * chunk size down to 256 bytes and if so we will need bits 8 and 9.
707  */
708 #define HAMMER2_AVF_SELMASK		0x03	/* select group */
709 #define HAMMER2_AVF_ALL_ALLOC		0x04	/* indicate all allocated */
710 #define HAMMER2_AVF_ALL_FREE		0x08	/* indicate all free */
711 #define HAMMER2_AVF_RESERVED10		0x10
712 #define HAMMER2_AVF_RESERVED20		0x20
713 #define HAMMER2_AVF_RESERVED40		0x40
714 #define HAMMER2_AVF_RESERVED80		0x80
715 #define HAMMER2_AVF_AVMASK32		((uint32_t)0xFFFFFF00LU)
716 #define HAMMER2_AVF_AVMASK64		((uint64_t)0xFFFFFFFFFFFFFF00LLU)
717 
718 #define HAMMER2_AV_SELECT_A		0x00
719 #define HAMMER2_AV_SELECT_B		0x01
720 #define HAMMER2_AV_SELECT_C		0x02
721 #define HAMMER2_AV_SELECT_D		0x03
722 
723 /*
724  * The volume header eats a 64K block.  There is currently an issue where
725  * we want to try to fit all nominal filesystem updates in a 512-byte section
726  * but it may be a lost cause due to the need for a blockset.
727  *
728  * All information is stored in host byte order.  The volume header's magic
729  * number may be checked to determine the byte order.  If you wish to mount
730  * between machines w/ different endian modes you'll need filesystem code
731  * which acts on the media data consistently (either all one way or all the
732  * other).  Our code currently does not do that.
733  *
734  * A read-write mount may have to recover missing allocations by doing an
735  * incremental mirror scan looking for modifications made after alloc_tid.
736  * If alloc_tid == last_tid then no recovery operation is needed.  Recovery
737  * operations are usually very, very fast.
738  *
739  * Read-only mounts do not need to do any recovery, access to the filesystem
740  * topology is always consistent after a crash (is always consistent, period).
741  * However, there may be shortcutted blockref updates present from deep in
742  * the tree which are stored in the volumeh eader and must be tracked on
743  * the fly.
744  *
745  * NOTE: The copyinfo[] array contains the configuration for both the
746  *	 cluster connections and any local media copies.  The volume
747  *	 header will be replicated for each local media copy.
748  *
749  *	 The mount command may specify multiple medias or just one and
750  *	 allow HAMMER2 to pick up the others when it checks the copyinfo[]
751  *	 array on mount.
752  *
753  * NOTE: root_blockref points to the super-root directory, not the root
754  *	 directory.  The root directory will be a subdirectory under the
755  *	 super-root.
756  *
757  *	 The super-root directory contains all root directories and all
758  *	 snapshots (readonly or writable).  It is possible to do a
759  *	 null-mount of the super-root using special path constructions
760  *	 relative to your mounted root.
761  *
762  * NOTE: HAMMER2 allows any subdirectory tree to be managed as if it were
763  *	 a PFS, including mirroring and storage quota operations, and this is
764  *	 prefered over creating discrete PFSs in the super-root.  Instead
765  *	 the super-root is most typically used to create writable snapshots,
766  *	 alternative roots, and so forth.  The super-root is also used by
767  *	 the automatic snapshotting mechanism.
768  */
769 #define HAMMER2_VOLUME_ID_HBO	0x48414d3205172011LLU
770 #define HAMMER2_VOLUME_ID_ABO	0x11201705324d4148LLU
771 
772 struct hammer2_volume_data {
773 	/*
774 	 * sector #0 - 512 bytes
775 	 */
776 	uint64_t	magic;			/* 0000 Signature */
777 	hammer2_off_t	boot_beg;		/* 0008 Boot area (future) */
778 	hammer2_off_t	boot_end;		/* 0010 (size = end - beg) */
779 	hammer2_off_t	aux_beg;		/* 0018 Aux area (future) */
780 	hammer2_off_t	aux_end;		/* 0020 (size = end - beg) */
781 	hammer2_off_t	volu_size;		/* 0028 Volume size, bytes */
782 
783 	uint32_t	version;		/* 0030 */
784 	uint32_t	flags;			/* 0034 */
785 	uint8_t		copyid;			/* 0038 copyid of phys vol */
786 	uint8_t		freemap_version;	/* 0039 freemap algorithm */
787 	uint8_t		peer_type;		/* 003A HAMMER2_PEER_xxx */
788 	uint8_t		reserved003B;		/* 003B */
789 	uint32_t	reserved003C;		/* 003C */
790 
791 	uuid_t		fsid;			/* 0040 */
792 	uuid_t		fstype;			/* 0050 */
793 
794 	/*
795 	 * allocator_size is precalculated at newfs time and does not include
796 	 * reserved blocks, boot, or redo areas.
797 	 *
798 	 * Initial non-reserved-area allocations do not use the freemap
799 	 * but instead adjust alloc_iterator.  Dynamic allocations take
800 	 * over starting at (allocator_beg).  This makes newfs_hammer2's
801 	 * job a lot easier and can also serve as a testing jig.
802 	 */
803 	hammer2_off_t	allocator_size;		/* 0060 Total data space */
804 	hammer2_off_t   allocator_free;		/* 0068	Free space */
805 	hammer2_off_t	allocator_beg;		/* 0070 Initial allocations */
806 	hammer2_tid_t	mirror_tid;		/* 0078 best committed tid */
807 	hammer2_tid_t	alloc_tid;		/* 0080 Alloctable modify tid */
808 	hammer2_blockref_t reserved0088;	/* 0088-00C7 */
809 
810 	/*
811 	 * Copyids are allocated dynamically from the copyexists bitmap.
812 	 * An id from the active copies set (up to 8, see copyinfo later on)
813 	 * may still exist after the copy set has been removed from the
814 	 * volume header and its bit will remain active in the bitmap and
815 	 * cannot be reused until it is 100% removed from the hierarchy.
816 	 */
817 	uint32_t	copyexists[8];		/* 00C8-00E7 copy exists bmap */
818 	char		reserved0140[248];	/* 00E8-01DF */
819 
820 	/*
821 	 * 32 bit CRC array at the end of the first 512 byte sector.
822 	 *
823 	 * icrc_sects[7] - First 512-4 bytes of volume header (including all
824 	 *		   the other icrc's except this one).
825 	 *
826 	 * icrc_sects[6] - Sector 1 (512 bytes) of volume header, which is
827 	 *		   the blockset for the root.
828 	 *
829 	 * icrc_sects[5] - Sector 2
830 	 * icrc_sects[4] - Sector 3
831 	 * icrc_sects[3] - Sector 4 (the freemap blockset)
832 	 */
833 	hammer2_crc32_t	icrc_sects[8];		/* 01E0-01FF */
834 
835 	/*
836 	 * sector #1 - 512 bytes
837 	 *
838 	 * The entire sector is used by a blockset.
839 	 */
840 	hammer2_blockset_t sroot_blockset;	/* 0200-03FF Superroot dir */
841 
842 	/*
843 	 * sector #2-7
844 	 */
845 	char	sector2[512];			/* 0400-05FF reserved */
846 	char	sector3[512];			/* 0600-07FF reserved */
847 	hammer2_blockset_t freemap_blockset;	/* 0800-09FF freemap  */
848 	char	sector5[512];			/* 0A00-0BFF reserved */
849 	char	sector6[512];			/* 0C00-0DFF reserved */
850 	char	sector7[512];			/* 0E00-0FFF reserved */
851 
852 	/*
853 	 * sector #8-71	- 32768 bytes
854 	 *
855 	 * Contains the configuration for up to 256 copyinfo targets.  These
856 	 * specify local and remote copies operating as masters or slaves.
857 	 * copyid's 0 and 255 are reserved (0 indicates an empty slot and 255
858 	 * indicates the local media).
859 	 *
860 	 * Each inode contains a set of up to 8 copyids, either inherited
861 	 * from its parent or explicitly specified in the inode, which
862 	 * indexes into this array.
863 	 */
864 						/* 1000-8FFF copyinfo config */
865 	dmsg_vol_data_t	copyinfo[HAMMER2_COPYID_COUNT];
866 
867 	/*
868 	 * Remaining sections are reserved for future use.
869 	 */
870 	char		reserved0400[0x6FFC];	/* 9000-FFFB reserved */
871 
872 	/*
873 	 * icrc on entire volume header
874 	 */
875 	hammer2_crc32_t	icrc_volheader;		/* FFFC-FFFF full volume icrc*/
876 };
877 
878 typedef struct hammer2_volume_data hammer2_volume_data_t;
879 
880 /*
881  * Various parts of the volume header have their own iCRCs.
882  *
883  * The first 512 bytes has its own iCRC stored at the end of the 512 bytes
884  * and not included the icrc calculation.
885  *
886  * The second 512 bytes also has its own iCRC but it is stored in the first
887  * 512 bytes so it covers the entire second 512 bytes.
888  *
889  * The whole volume block (64KB) has an iCRC covering all but the last 4 bytes,
890  * which is where the iCRC for the whole volume is stored.  This is currently
891  * a catch-all for anything not individually iCRCd.
892  */
893 #define HAMMER2_VOL_ICRC_SECT0		7
894 #define HAMMER2_VOL_ICRC_SECT1		6
895 
896 #define HAMMER2_VOLUME_BYTES		65536
897 
898 #define HAMMER2_VOLUME_ICRC0_OFF	0
899 #define HAMMER2_VOLUME_ICRC1_OFF	512
900 #define HAMMER2_VOLUME_ICRCVH_OFF	0
901 
902 #define HAMMER2_VOLUME_ICRC0_SIZE	(512 - 4)
903 #define HAMMER2_VOLUME_ICRC1_SIZE	(512)
904 #define HAMMER2_VOLUME_ICRCVH_SIZE	(65536 - 4)
905 
906 #define HAMMER2_VOL_VERSION_MIN		1
907 #define HAMMER2_VOL_VERSION_DEFAULT	1
908 #define HAMMER2_VOL_VERSION_WIP 	2
909 
910 #define HAMMER2_NUM_VOLHDRS		4
911 
912 union hammer2_media_data {
913 	hammer2_volume_data_t	voldata;
914         hammer2_inode_data_t    ipdata;
915 	hammer2_indblock_data_t npdata;
916 	hammer2_bmap_data_t	bmdata;
917 	char			buf[HAMMER2_PBUFSIZE];
918 };
919 
920 typedef union hammer2_media_data hammer2_media_data_t;
921 
922 #endif
923