xref: /dragonfly/sys/vfs/hammer2/hammer2_disk.h (revision 9443de1e697b0500d2fe9da1bb2a23769759c93b)
1 /*
2  * Copyright (c) 2011-2019 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 
36 #ifndef _VFS_HAMMER2_DISK_H_
37 #define _VFS_HAMMER2_DISK_H_
38 
39 #ifndef _SYS_UUID_H_
40 #include <sys/uuid.h>
41 #endif
42 #ifndef _SYS_DMSG_H_
43 #include <sys/dmsg.h>
44 #endif
45 
46 /*
47  * The structures below represent the on-disk media structures for the HAMMER2
48  * filesystem.  Note that all fields for on-disk structures are naturally
49  * aligned.  The host endian format is typically used - compatibility is
50  * possible if the implementation detects reversed endian and adjusts accesses
51  * accordingly.
52  *
53  * HAMMER2 primarily revolves around the directory topology:  inodes,
54  * directory entries, and block tables.  Block device buffer cache buffers
55  * are always 64KB.  Logical file buffers are typically 16KB.  All data
56  * references utilize 64-bit byte offsets.
57  *
58  * Free block management is handled independently using blocks reserved by
59  * the media topology.
60  */
61 
62 /*
63  * The data at the end of a file or directory may be a fragment in order
64  * to optimize storage efficiency.  The minimum fragment size is 1KB.
65  * Since allocations are in powers of 2 fragments must also be sized in
66  * powers of 2 (1024, 2048, ... 65536).
67  *
68  * For the moment the maximum allocation size is HAMMER2_PBUFSIZE (64K),
69  * which is 2^16.  Larger extents may be supported in the future.  Smaller
70  * fragments might be supported in the future (down to 64 bytes is possible),
71  * but probably will not be.
72  *
73  * A full indirect block use supports 512 x 128-byte blockrefs in a 64KB
74  * buffer.  Indirect blocks down to 1KB are supported to keep small
75  * directories small.
76  *
77  * A maximally sized file (2^64-1 bytes) requires ~6 indirect block levels
78  * using 64KB indirect blocks (128 byte refs, 512 or radix 9 per indblk).
79  *
80  *        16(datablk) + 9 + 9 + 9 + 9 + 9 + 9 = ~70.
81  *        16(datablk) + 7 + 9 + 9 + 9 + 9 + 9 = ~68.  (smaller top level indblk)
82  *
83  * The actual depth depends on copies redundancy and whether the filesystem
84  * has chosen to use a smaller indirect block size at the top level or not.
85  */
86 #define HAMMER2_ALLOC_MIN     1024      /* minimum allocation size */
87 #define HAMMER2_RADIX_MIN     10        /* minimum allocation size 2^N */
88 #define HAMMER2_ALLOC_MAX     65536     /* maximum allocation size */
89 #define HAMMER2_RADIX_MAX     16        /* maximum allocation size 2^N */
90 #define HAMMER2_RADIX_KEY     64        /* number of bits in key */
91 
92 /*
93  * HAMMER2_LBUFSIZE - Nominal buffer size for I/O rollups.
94  *
95  * HAMMER2_PBUFSIZE - Topological block size used by files for all
96  *                              blocks except the block straddling EOF.
97  *
98  * HAMMER2_SEGSIZE  - Allocation map segment size, typically 4MB
99  *                              (space represented by a level0 bitmap).
100  */
101 
102 #define HAMMER2_SEGSIZE                 (1 << HAMMER2_FREEMAP_LEVEL0_RADIX)
103 #define HAMMER2_SEGRADIX      HAMMER2_FREEMAP_LEVEL0_RADIX
104 
105 #define HAMMER2_PBUFRADIX     16        /* physical buf (1<<16) bytes */
106 #define HAMMER2_PBUFSIZE      65536
107 #define HAMMER2_LBUFRADIX     14        /* logical buf (1<<14) bytes */
108 #define HAMMER2_LBUFSIZE      16384
109 
110 #define HAMMER2_IND_BYTES_MIN 4096
111 #define HAMMER2_IND_BYTES_NOM HAMMER2_LBUFSIZE
112 #define HAMMER2_IND_BYTES_MAX HAMMER2_PBUFSIZE
113 #define HAMMER2_IND_RADIX_MIN 12
114 #define HAMMER2_IND_RADIX_NOM HAMMER2_LBUFRADIX
115 #define HAMMER2_IND_RADIX_MAX HAMMER2_PBUFRADIX
116 #define HAMMER2_IND_COUNT_MIN (HAMMER2_IND_BYTES_MIN / \
117                                          sizeof(hammer2_blockref_t))
118 #define HAMMER2_IND_COUNT_NOM (HAMMER2_IND_BYTES_NOM / \
119                                          sizeof(hammer2_blockref_t))
120 #define HAMMER2_IND_COUNT_MAX (HAMMER2_IND_BYTES_MAX / \
121                                          sizeof(hammer2_blockref_t))
122 
123 /*
124  * In HAMMER2, arrays of blockrefs are fully set-associative, meaning that
125  * any element can occur at any index and holes can be anywhere.
126  *
127  * Inodes embed either 512 bytes of direct data or an array of 4 blockrefs,
128  * resulting in highly efficient storage for files <= 512 bytes and for files
129  * <= 512KB.  Up to 4 directory entries can be referenced from a directory
130  * without requiring an indirect block.
131  */
132 #define HAMMER2_SET_RADIX               2         /* radix 2 = 4 entries */
133 #define HAMMER2_SET_COUNT               (1 << HAMMER2_SET_RADIX)
134 #define HAMMER2_EMBEDDED_BYTES                    512       /* inode blockset/dd size */
135 #define HAMMER2_EMBEDDED_RADIX                    9
136 
137 #define HAMMER2_PBUFMASK      (HAMMER2_PBUFSIZE - 1)
138 #define HAMMER2_LBUFMASK      (HAMMER2_LBUFSIZE - 1)
139 #define HAMMER2_SEGMASK                 (HAMMER2_SEGSIZE - 1)
140 
141 #define HAMMER2_LBUFMASK64    ((hammer2_off_t)HAMMER2_LBUFMASK)
142 #define HAMMER2_PBUFSIZE64    ((hammer2_off_t)HAMMER2_PBUFSIZE)
143 #define HAMMER2_PBUFMASK64    ((hammer2_off_t)HAMMER2_PBUFMASK)
144 #define HAMMER2_SEGSIZE64     ((hammer2_off_t)HAMMER2_SEGSIZE)
145 #define HAMMER2_SEGMASK64     ((hammer2_off_t)HAMMER2_SEGMASK)
146 
147 #define HAMMER2_UUID_STRING   "5cbb9ad1-862d-11dc-a94d-01301bb8a9f5"
148 
149 /*
150  * A 4MB segment is reserved at the beginning of each 1GB.  This segment
151  * contains the volume header (or backup volume header), the free block
152  * table, and possibly other information in the future.
153  *
154  * 4MB = 64 x 64K blocks.  Each 4MB segment is broken down as follows:
155  *
156  * ==========
157  *  0 volume header (for the first four 2GB zones)
158  *  1 freemap00 level1 FREEMAP_LEAF (256 x 128B bitmap data per 1GB)
159  *  2           level2 FREEMAP_NODE (256 x 128B indirect block per 256GB)
160  *  3           level3 FREEMAP_NODE (256 x 128B indirect block per 64TB)
161  *  4           level4 FREEMAP_NODE (256 x 128B indirect block per 16PB)
162  *  5           level5 FREEMAP_NODE (256 x 128B indirect block per 4EB)
163  *  6 freemap01 level1 (rotation)
164  *  7           level2
165  *  8           level3
166  *  9           level4
167  * 10           level5
168  * 11 freemap02 level1 (rotation)
169  * 12           level2
170  * 13           level3
171  * 14           level4
172  * 15           level5
173  * 16 freemap03 level1 (rotation)
174  * 17           level2
175  * 18           level3
176  * 19           level4
177  * 20           level5
178  * 21 freemap04 level1 (rotation)
179  * 22           level2
180  * 23           level3
181  * 24           level4
182  * 25           level5
183  * 26 freemap05 level1 (rotation)
184  * 27           level2
185  * 28           level3
186  * 29           level4
187  * 30           level5
188  * 31 freemap06 level1 (rotation)
189  * 32           level2
190  * 33           level3
191  * 34           level4
192  * 35           level5
193  * 36 freemap07 level1 (rotation)
194  * 37           level2
195  * 38           level3
196  * 39           level4
197  * 40           level5
198  * 41 unused
199  * .. unused
200  * 63 unused
201  * ==========
202  *
203  * The first four 2GB zones contain volume headers and volume header backups.
204  * After that the volume header block# is reserved for future use.  Similarly,
205  * there are many blocks related to various Freemap levels which are not
206  * used in every segment and those are also reserved for future use.
207  * Note that each FREEMAP_LEAF or FREEMAP_NODE uses 32KB out of 64KB slot.
208  *
209  *                            Freemap (see the FREEMAP document)
210  *
211  * The freemap utilizes blocks #1-40 in 8 sets of 5 blocks.  Each block in
212  * a set represents a level of depth in the freemap topology.  Eight sets
213  * exist to prevent live updates from disturbing the state of the freemap
214  * were a crash/reboot to occur.  That is, a live update is not committed
215  * until the update's flush reaches the volume root.  There are FOUR volume
216  * roots representing the last four synchronization points, so the freemap
217  * must be consistent no matter which volume root is chosen by the mount
218  * code.
219  *
220  * Each freemap set is 5 x 64K blocks and represents the 1GB, 256GB, 64TB,
221  * 16PB and 4EB indirect map.  The volume header itself has a set of 4 freemap
222  * blockrefs representing another 2 bits, giving us a total 64 bits of
223  * representable address space.
224  *
225  * The Level 0 64KB block represents 1GB of storage represented by 32KB
226  * (256 x struct hammer2_bmap_data).  Each structure represents 4MB of storage
227  * and has a 512 bit bitmap, using 2 bits to represent a 16KB chunk of
228  * storage.  These 2 bits represent the following states:
229  *
230  *        00        Free
231  *        01        (reserved) (Possibly partially allocated)
232  *        10        Possibly free
233  *        11        Allocated
234  *
235  * One important thing to note here is that the freemap resolution is 16KB,
236  * but the minimum storage allocation size is 1KB.  The hammer2 vfs keeps
237  * track of sub-allocations in memory, which means that on a unmount or reboot
238  * the entire 16KB of a partially allocated block will be considered fully
239  * allocated.  It is possible for fragmentation to build up over time, but
240  * defragmentation is fairly easy to accomplish since all modifications
241  * allocate a new block.
242  *
243  * The Second thing to note is that due to the way snapshots and inode
244  * replication works, deleting a file cannot immediately free the related
245  * space.  Furthermore, deletions often do not bother to traverse the
246  * block subhierarchy being deleted.  And to go even further, whole
247  * sub-directory trees can be deleted simply by deleting the directory inode
248  * at the top.  So even though we have a symbol to represent a 'possibly free'
249  * block (binary 10), only the bulk free scanning code can actually use it.
250  * Normal 'rm's or other deletions do not.
251  *
252  * WARNING!  ZONE_SEG and VOLUME_ALIGN must be a multiple of 1<<LEVEL0_RADIX
253  *             (i.e. a multiple of 4MB).  VOLUME_ALIGN must be >= ZONE_SEG.
254  *
255  * In Summary:
256  *
257  * (1) Modifications to freemap blocks 'allocate' a new copy (aka use a block
258  *     from the next set).  The new copy is reused until a flush occurs at
259  *     which point the next modification will then rotate to the next set.
260  */
261 #define HAMMER2_VOLUME_ALIGN            (8 * 1024 * 1024)
262 #define HAMMER2_VOLUME_ALIGN64                    ((hammer2_off_t)HAMMER2_VOLUME_ALIGN)
263 #define HAMMER2_VOLUME_ALIGNMASK        (HAMMER2_VOLUME_ALIGN - 1)
264 #define HAMMER2_VOLUME_ALIGNMASK64      ((hammer2_off_t)HAMMER2_VOLUME_ALIGNMASK)
265 
266 #define HAMMER2_NEWFS_ALIGN             (HAMMER2_VOLUME_ALIGN)
267 #define HAMMER2_NEWFS_ALIGN64           ((hammer2_off_t)HAMMER2_VOLUME_ALIGN)
268 #define HAMMER2_NEWFS_ALIGNMASK                   (HAMMER2_VOLUME_ALIGN - 1)
269 #define HAMMER2_NEWFS_ALIGNMASK64       ((hammer2_off_t)HAMMER2_NEWFS_ALIGNMASK)
270 
271 #define HAMMER2_ZONE_BYTES64            (2LLU * 1024 * 1024 * 1024)
272 #define HAMMER2_ZONE_MASK64             (HAMMER2_ZONE_BYTES64 - 1)
273 #define HAMMER2_ZONE_SEG                (4 * 1024 * 1024)
274 #define HAMMER2_ZONE_SEG64              ((hammer2_off_t)HAMMER2_ZONE_SEG)
275 #define HAMMER2_ZONE_BLOCKS_SEG                   (HAMMER2_ZONE_SEG / HAMMER2_PBUFSIZE)
276 
277 #define HAMMER2_ZONE_FREEMAP_INC        5         /* 5 deep */
278 
279 #define HAMMER2_ZONE_VOLHDR             0         /* volume header or backup */
280 #define HAMMER2_ZONE_FREEMAP_00                   1         /* normal freemap rotation */
281 #define HAMMER2_ZONE_FREEMAP_01                   6         /* normal freemap rotation */
282 #define HAMMER2_ZONE_FREEMAP_02                   11        /* normal freemap rotation */
283 #define HAMMER2_ZONE_FREEMAP_03                   16        /* normal freemap rotation */
284 #define HAMMER2_ZONE_FREEMAP_04                   21        /* normal freemap rotation */
285 #define HAMMER2_ZONE_FREEMAP_05                   26        /* normal freemap rotation */
286 #define HAMMER2_ZONE_FREEMAP_06                   31        /* normal freemap rotation */
287 #define HAMMER2_ZONE_FREEMAP_07                   36        /* normal freemap rotation */
288 #define HAMMER2_ZONE_FREEMAP_END        41        /* (non-inclusive) */
289 
290 #define HAMMER2_ZONE_UNUSED41           41
291 #define HAMMER2_ZONE_UNUSED42           42
292 #define HAMMER2_ZONE_UNUSED43           43
293 #define HAMMER2_ZONE_UNUSED44           44
294 #define HAMMER2_ZONE_UNUSED45           45
295 #define HAMMER2_ZONE_UNUSED46           46
296 #define HAMMER2_ZONE_UNUSED47           47
297 #define HAMMER2_ZONE_UNUSED48           48
298 #define HAMMER2_ZONE_UNUSED49           49
299 #define HAMMER2_ZONE_UNUSED50           50
300 #define HAMMER2_ZONE_UNUSED51           51
301 #define HAMMER2_ZONE_UNUSED52           52
302 #define HAMMER2_ZONE_UNUSED53           53
303 #define HAMMER2_ZONE_UNUSED54           54
304 #define HAMMER2_ZONE_UNUSED55           55
305 #define HAMMER2_ZONE_UNUSED56           56
306 #define HAMMER2_ZONE_UNUSED57           57
307 #define HAMMER2_ZONE_UNUSED58           58
308 #define HAMMER2_ZONE_UNUSED59           59
309 #define HAMMER2_ZONE_UNUSED60           60
310 #define HAMMER2_ZONE_UNUSED61           61
311 #define HAMMER2_ZONE_UNUSED62           62
312 #define HAMMER2_ZONE_UNUSED63           63
313 #define HAMMER2_ZONE_END                64        /* non-inclusive */
314 
315 #define HAMMER2_NFREEMAPS               8         /* FREEMAP_00 - FREEMAP_07 */
316 
317                                                             /* relative to FREEMAP_x */
318 #define HAMMER2_ZONEFM_LEVEL1           0         /* 1GB leafmap */
319 #define HAMMER2_ZONEFM_LEVEL2           1         /* 256GB indmap */
320 #define HAMMER2_ZONEFM_LEVEL3           2         /* 64TB indmap */
321 #define HAMMER2_ZONEFM_LEVEL4           3         /* 16PB indmap */
322 #define HAMMER2_ZONEFM_LEVEL5           4         /* 4EB indmap */
323 /* LEVEL6 is a set of 4 blockrefs in the volume header 16EB */
324 
325 /*
326  * Freemap radix.  Assumes a set-count of 4, 128-byte blockrefs,
327  * 32KB indirect block for freemap (LEVELN_PSIZE below).
328  *
329  * Leaf entry represents 4MB of storage broken down into a 512-bit
330  * bitmap, 2-bits per entry.  So course bitmap item represents 16KB.
331  */
332 #if HAMMER2_SET_COUNT != 4
333 #error "hammer2_disk.h - freemap assumes SET_COUNT is 4"
334 #endif
335 #define HAMMER2_FREEMAP_LEVEL6_RADIX    64        /* 16EB (end) */
336 #define HAMMER2_FREEMAP_LEVEL5_RADIX    62        /* 4EB */
337 #define HAMMER2_FREEMAP_LEVEL4_RADIX    54        /* 16PB */
338 #define HAMMER2_FREEMAP_LEVEL3_RADIX    46        /* 64TB */
339 #define HAMMER2_FREEMAP_LEVEL2_RADIX    38        /* 256GB */
340 #define HAMMER2_FREEMAP_LEVEL1_RADIX    30        /* 1GB */
341 #define HAMMER2_FREEMAP_LEVEL0_RADIX    22        /* 4MB (x 256 in l-1 leaf) */
342 
343 #define HAMMER2_FREEMAP_LEVELN_PSIZE    32768     /* physical bytes */
344 
345 #define HAMMER2_FREEMAP_LEVEL5_SIZE     ((hammer2_off_t)1 <<                    \
346                                                    HAMMER2_FREEMAP_LEVEL5_RADIX)
347 #define HAMMER2_FREEMAP_LEVEL4_SIZE     ((hammer2_off_t)1 <<                    \
348                                                    HAMMER2_FREEMAP_LEVEL4_RADIX)
349 #define HAMMER2_FREEMAP_LEVEL3_SIZE     ((hammer2_off_t)1 <<                    \
350                                                    HAMMER2_FREEMAP_LEVEL3_RADIX)
351 #define HAMMER2_FREEMAP_LEVEL2_SIZE     ((hammer2_off_t)1 <<                    \
352                                                    HAMMER2_FREEMAP_LEVEL2_RADIX)
353 #define HAMMER2_FREEMAP_LEVEL1_SIZE     ((hammer2_off_t)1 <<                    \
354                                                    HAMMER2_FREEMAP_LEVEL1_RADIX)
355 #define HAMMER2_FREEMAP_LEVEL0_SIZE     ((hammer2_off_t)1 <<                    \
356                                                    HAMMER2_FREEMAP_LEVEL0_RADIX)
357 
358 #define HAMMER2_FREEMAP_LEVEL5_MASK     (HAMMER2_FREEMAP_LEVEL5_SIZE - 1)
359 #define HAMMER2_FREEMAP_LEVEL4_MASK     (HAMMER2_FREEMAP_LEVEL4_SIZE - 1)
360 #define HAMMER2_FREEMAP_LEVEL3_MASK     (HAMMER2_FREEMAP_LEVEL3_SIZE - 1)
361 #define HAMMER2_FREEMAP_LEVEL2_MASK     (HAMMER2_FREEMAP_LEVEL2_SIZE - 1)
362 #define HAMMER2_FREEMAP_LEVEL1_MASK     (HAMMER2_FREEMAP_LEVEL1_SIZE - 1)
363 #define HAMMER2_FREEMAP_LEVEL0_MASK     (HAMMER2_FREEMAP_LEVEL0_SIZE - 1)
364 
365 #define HAMMER2_FREEMAP_COUNT           (int)(HAMMER2_FREEMAP_LEVELN_PSIZE / \
366                                                    sizeof(hammer2_bmap_data_t))
367 
368 /*
369  * XXX I made a mistake and made the reserved area begin at each LEVEL1 zone,
370  *     which is on a 1GB demark.  This will eat a little more space but for
371  *     now we retain compatibility and make FMZONEBASE every 1GB
372  */
373 #define H2FMZONEBASE(key)     ((key) & ~HAMMER2_FREEMAP_LEVEL1_MASK)
374 #define H2FMBASE(key, radix)  rounddown2(key, (hammer2_off_t)1 << (radix))
375 
376 /*
377  * 16KB bitmap granularity (x2 bits per entry).
378  */
379 #define HAMMER2_FREEMAP_BLOCK_RADIX     14
380 #define HAMMER2_FREEMAP_BLOCK_SIZE      (1 << HAMMER2_FREEMAP_BLOCK_RADIX)
381 #define HAMMER2_FREEMAP_BLOCK_MASK      (HAMMER2_FREEMAP_BLOCK_SIZE - 1)
382 
383 /*
384  * bitmap[] structure.  2 bits per HAMMER2_FREEMAP_BLOCK_SIZE.
385  *
386  * 8 x 64-bit elements, 2 bits per block.
387  * 32 blocks (radix 5) per element.
388  * representing INDEX_SIZE bytes worth of storage per element.
389  */
390 
391 typedef uint64_t hammer2_bitmap_t;
392 
393 #define HAMMER2_BMAP_ALLONES            ((hammer2_bitmap_t)-1)
394 #define HAMMER2_BMAP_ELEMENTS           8
395 #define HAMMER2_BMAP_BITS_PER_ELEMENT   64
396 #define HAMMER2_BMAP_INDEX_RADIX        5         /* 32 blocks per element */
397 #define HAMMER2_BMAP_BLOCKS_PER_ELEMENT (1 << HAMMER2_BMAP_INDEX_RADIX)
398 
399 #define HAMMER2_BMAP_INDEX_SIZE                   (HAMMER2_FREEMAP_BLOCK_SIZE * \
400                                                    HAMMER2_BMAP_BLOCKS_PER_ELEMENT)
401 #define HAMMER2_BMAP_INDEX_MASK                   (HAMMER2_BMAP_INDEX_SIZE - 1)
402 
403 #define HAMMER2_BMAP_SIZE               (HAMMER2_BMAP_INDEX_SIZE * \
404                                                    HAMMER2_BMAP_ELEMENTS)
405 #define HAMMER2_BMAP_MASK               (HAMMER2_BMAP_SIZE - 1)
406 
407 /*
408  * Two linear areas can be reserved after the initial 4MB segment in the base
409  * zone (the one starting at offset 0).  These areas are NOT managed by the
410  * block allocator and do not fall under HAMMER2 crc checking rules based
411  * at the volume header (but can be self-CRCd internally, depending).
412  */
413 #define HAMMER2_BOOT_MIN_BYTES                    HAMMER2_VOLUME_ALIGN
414 #define HAMMER2_BOOT_NOM_BYTES                    (64*1024*1024)
415 #define HAMMER2_BOOT_MAX_BYTES                    (256*1024*1024)
416 
417 #define HAMMER2_AUX_MIN_BYTES           HAMMER2_VOLUME_ALIGN
418 #define HAMMER2_AUX_NOM_BYTES           (256*1024*1024)
419 #define HAMMER2_AUX_MAX_BYTES           (1024*1024*1024)
420 
421 /*
422  * Most HAMMER2 types are implemented as unsigned 64-bit integers.
423  * Transaction ids are monotonic.
424  *
425  * We utilize 32-bit iSCSI CRCs.
426  */
427 typedef uint64_t hammer2_tid_t;
428 typedef uint64_t hammer2_off_t;
429 typedef uint64_t hammer2_key_t;
430 typedef uint32_t hammer2_crc32_t;
431 
432 /*
433  * Miscellaneous ranges (all are unsigned).
434  */
435 #define HAMMER2_TID_MIN                 1ULL
436 #define HAMMER2_TID_MAX                 0xFFFFFFFFFFFFFFFFULL
437 #define HAMMER2_KEY_MIN                 0ULL
438 #define HAMMER2_KEY_MAX                 0xFFFFFFFFFFFFFFFFULL
439 
440 /*
441  * HAMMER2 data offset special cases and masking.
442  *
443  * All HAMMER2 data offsets have to be broken down into a 64K buffer base
444  * offset (HAMMER2_OFF_MASK_HI) and a 64K buffer index (HAMMER2_OFF_MASK_LO).
445  *
446  * Indexes into physical buffers are always 64-byte aligned.  The low 6 bits
447  * of the data offset field specifies how large the data chunk being pointed
448  * to as a power of 2.  The theoretical minimum radix is thus 6 (The space
449  * needed in the low bits of the data offset field).  However, the practical
450  * minimum allocation chunk size is 1KB (a radix of 10), so HAMMER2 sets
451  * HAMMER2_RADIX_MIN to 10.  The maximum radix is currently 16 (64KB), but
452  * we fully intend to support larger extents in the future.
453  *
454  * WARNING! A radix of 0 (such as when data_off is all 0's) is a special
455  *            case which means no data associated with the blockref, and
456  *            not the '1 byte' it would otherwise calculate to.
457  */
458 #define HAMMER2_OFF_MASK      0xFFFFFFFFFFFFFFC0ULL
459 #define HAMMER2_OFF_MASK_LO   (HAMMER2_OFF_MASK & HAMMER2_PBUFMASK64)
460 #define HAMMER2_OFF_MASK_HI   (~HAMMER2_PBUFMASK64)
461 #define HAMMER2_OFF_MASK_RADIX          0x000000000000003FULL
462 
463 /*
464  * HAMMER2 directory support and pre-defined keys
465  */
466 #define HAMMER2_DIRHASH_VISIBLE         0x8000000000000000ULL
467 #define HAMMER2_DIRHASH_USERMSK         0x7FFFFFFFFFFFFFFFULL
468 #define HAMMER2_DIRHASH_LOMASK          0x0000000000007FFFULL
469 #if 0
470 #define HAMMER2_DIRHASH_HIMASK          0xFFFFFFFFFFFF0000ULL
471 #define HAMMER2_DIRHASH_FORCED          0x0000000000008000ULL         /* bit forced on */
472 #endif
473 
474 #define HAMMER2_SROOT_KEY     0x0000000000000000ULL         /* volume to sroot */
475 #define HAMMER2_BOOT_KEY      0xd9b36ce135528000ULL         /* sroot to BOOT PFS */
476 
477 /************************************************************************
478  *                                      DMSG SUPPORT                                      *
479  ************************************************************************
480  * LNK_VOLCONF
481  *
482  * All HAMMER2 directories directly under the super-root on your local
483  * media can be mounted separately, even if they share the same physical
484  * device.
485  *
486  * When you do a HAMMER2 mount you are effectively tying into a HAMMER2
487  * cluster via local media.  The local media does not have to participate
488  * in the cluster, other than to provide the hammer2_volconf[] array and
489  * root inode for the mount.
490  *
491  * This is important: The mount device path you specify serves to bootstrap
492  * your entry into the cluster, but your mount will make active connections
493  * to ALL copy elements in the hammer2_volconf[] array which match the
494  * PFSID of the directory in the super-root that you specified.  The local
495  * media path does not have to be mentioned in this array but becomes part
496  * of the cluster based on its type and access rights.  ALL ELEMENTS ARE
497  * TREATED ACCORDING TO TYPE NO MATTER WHICH ONE YOU MOUNT FROM.
498  *
499  * The actual cluster may be far larger than the elements you list in the
500  * hammer2_volconf[] array.  You list only the elements you wish to
501  * directly connect to and you are able to access the rest of the cluster
502  * indirectly through those connections.
503  *
504  * WARNING!  This structure must be exactly 128 bytes long for its config
505  *             array to fit in the volume header.
506  */
507 struct hammer2_volconf {
508           uint8_t   copyid;             /* 00      copyid 0-255 (must match slot) */
509           uint8_t inprog;               /* 01      operation in progress, or 0 */
510           uint8_t chain_to;   /* 02      operation chaining to, or 0 */
511           uint8_t chain_from; /* 03      operation chaining from, or 0 */
512           uint16_t flags;               /* 04-05 flags field */
513           uint8_t error;                /* 06      last operational error */
514           uint8_t priority;   /* 07      priority and round-robin flag */
515           uint8_t remote_pfs_type;/* 08  probed direct remote PFS type */
516           uint8_t reserved08[23];       /* 09-1F */
517           uuid_t    pfs_clid; /* 20-2F copy target must match this uuid */
518           uint8_t label[16];  /* 30-3F import/export label */
519           uint8_t path[64];   /* 40-7F target specification string or key */
520 } __packed;
521 
522 typedef struct hammer2_volconf hammer2_volconf_t;
523 
524 #define DMSG_VOLF_ENABLED     0x0001
525 #define DMSG_VOLF_INPROG      0x0002
526 #define DMSG_VOLF_CONN_RR     0x80      /* round-robin at same priority */
527 #define DMSG_VOLF_CONN_EF     0x40      /* media errors flagged */
528 #define DMSG_VOLF_CONN_PRI    0x0F      /* select priority 0-15 (15=best) */
529 
530 struct dmsg_lnk_hammer2_volconf {
531           dmsg_hdr_t                    head;
532           hammer2_volconf_t   copy;     /* copy spec */
533           int32_t                       index;
534           int32_t                       unused01;
535           uuid_t                        mediaid;
536           int64_t                       reserved02[32];
537 } __packed;
538 
539 typedef struct dmsg_lnk_hammer2_volconf dmsg_lnk_hammer2_volconf_t;
540 
541 #define DMSG_LNK_HAMMER2_VOLCONF DMSG_LNK(DMSG_LNK_CMD_HAMMER2_VOLCONF, \
542                                                     dmsg_lnk_hammer2_volconf)
543 
544 #define H2_LNK_VOLCONF(msg)   ((dmsg_lnk_hammer2_volconf_t *)(msg)->any.buf)
545 
546 /*
547  * HAMMER2 directory entry header (embedded in blockref)  exactly 16 bytes
548  */
549 struct hammer2_dirent_head {
550           hammer2_tid_t                 inum;               /* inode number */
551           uint16_t            namlen;             /* name length */
552           uint8_t                       type;               /* OBJTYPE_*        */
553           uint8_t                       unused0B;
554           uint8_t                       unused0C[4];
555 } __packed;
556 
557 typedef struct hammer2_dirent_head hammer2_dirent_head_t;
558 
559 /*
560  * The media block reference structure.  This forms the core of the HAMMER2
561  * media topology recursion.  This 128-byte data structure is embedded in the
562  * volume header, in inodes (which are also directory entries), and in
563  * indirect blocks.
564  *
565  * A blockref references a single media item, which typically can be a
566  * directory entry (aka inode), indirect block, or data block.
567  *
568  * The primary feature a blockref represents is the ability to validate
569  * the entire tree underneath it via its check code.  Any modification to
570  * anything propagates up the blockref tree all the way to the root, replacing
571  * the related blocks and compounding the generated check code.
572  *
573  * The check code can be a simple 32-bit iscsi code, a 64-bit crc, or as
574  * complex as a 512 bit cryptographic hash.  I originally used a 64-byte
575  * blockref but later expanded it to 128 bytes to be able to support the
576  * larger check code as well as to embed statistics for quota operation.
577  *
578  * Simple check codes are not sufficient for unverified dedup.  Even with
579  * a maximally-sized check code unverified dedup should only be used in
580  * subdirectory trees where you do not need 100% data integrity.
581  *
582  * Unverified dedup is deduping based on meta-data only without verifying
583  * that the data blocks are actually identical.  Verified dedup guarantees
584  * integrity but is a far more I/O-expensive operation.
585  *
586  * --
587  *
588  * mirror_tid - per cluster node modified (propagated upward by flush)
589  * modify_tid - clc record modified (not propagated).
590  * update_tid - clc record updated (propagated upward on verification)
591  *
592  * CLC - Stands for 'Cluster Level Change', identifiers which are identical
593  *         within the topology across all cluster nodes (when fully
594  *         synchronized).
595  *
596  * NOTE: The range of keys represented by the blockref is (key) to
597  *         ((key) + (1LL << keybits) - 1).  HAMMER2 usually populates
598  *         blocks bottom-up, inserting a new root when radix expansion
599  *         is required.
600  *
601  * leaf_count  - Helps manage leaf collapse calculations when indirect
602  *                   blocks become mostly empty.  This value caps out at
603  *                   HAMMER2_BLOCKREF_LEAF_MAX (65535).
604  *
605  *                   Used by the chain code to determine when to pull leafs up
606  *                   from nearly empty indirect blocks.  For the purposes of this
607  *                   calculation, BREF_TYPE_INODE is considered a leaf, along
608  *                   with DIRENT and DATA.
609  *
610  *                                          RESERVED FIELDS
611  *
612  * A number of blockref fields are reserved and should generally be set to
613  * 0 for future compatibility.
614  *
615  *                                      FUTURE BLOCKREF EXPANSION
616  *
617  * CONTENT ADDRESSABLE INDEXING (future) - Using a 256 or 512-bit check code.
618  */
619 struct hammer2_blockref {               /* MUST BE EXACTLY 128 BYTES */
620           uint8_t             type;               /* type of underlying item */
621           uint8_t             methods;  /* check method & compression method */
622           uint8_t             copyid;             /* specify which copy this is */
623           uint8_t             keybits;  /* #of keybits masked off 0=leaf */
624           uint8_t             vradix;             /* virtual data/meta-data size */
625           uint8_t             flags;              /* blockref flags */
626           uint16_t  leaf_count;         /* leaf aggregation count */
627           hammer2_key_t       key;                /* key specification */
628           hammer2_tid_t       mirror_tid;         /* media flush topology & freemap */
629           hammer2_tid_t       modify_tid;         /* clc modify (not propagated) */
630           hammer2_off_t       data_off; /* low 6 bits is phys size (radix)*/
631           hammer2_tid_t       update_tid;         /* clc modify (propagated upward) */
632           union {
633                     char      buf[16];
634 
635                     /*
636                      * Directory entry header (BREF_TYPE_DIRENT)
637                      *
638                      * NOTE: check.buf contains filename if <= 64 bytes.  Longer
639                      *         filenames are stored in a data reference of size
640                      *         HAMMER2_ALLOC_MIN (at least 256, typically 1024).
641                      *
642                      * NOTE: inode structure may contain a copy of a recently
643                      *         associated filename, for recovery purposes.
644                      *
645                      * NOTE: Superroot entries are INODEs, not DIRENTs.  Code
646                      *         allows both cases.
647                      */
648                     hammer2_dirent_head_t dirent;
649 
650                     /*
651                      * Statistics aggregation (BREF_TYPE_INODE, BREF_TYPE_INDIRECT)
652                      */
653                     struct {
654                               hammer2_key_t       data_count;
655                               hammer2_key_t       inode_count;
656                     } stats;
657           } embed;
658           union {                                 /* check info */
659                     char      buf[64];
660                     struct {
661                               uint32_t value;
662                               uint32_t reserved[15];
663                     } iscsi32;
664                     struct {
665                               uint64_t value;
666                               uint64_t reserved[7];
667                     } xxhash64;
668                     struct {
669                               char data[24];
670                               char reserved[40];
671                     } sha192;
672                     struct {
673                               char data[32];
674                               char reserved[32];
675                     } sha256;
676                     struct {
677                               char data[64];
678                     } sha512;
679 
680                     /*
681                      * Freemap hints are embedded in addition to the icrc32.
682                      *
683                      * bigmask - Radixes available for allocation (0-31).
684                      *             Heuristical (may be permissive but not
685                      *             restrictive).  Typically only radix values
686                      *             10-16 are used (i.e. (1<<10) through (1<<16)).
687                      *
688                      * avail   - Total available space remaining, in bytes
689                      */
690                     struct {
691                               uint32_t icrc32;
692                               uint32_t bigmask;   /* available radixes */
693                               uint64_t avail;               /* total available bytes */
694                               char reserved[48];
695                     } freemap;
696           } check;
697 } __packed;
698 
699 typedef struct hammer2_blockref hammer2_blockref_t;
700 
701 #define HAMMER2_BLOCKREF_BYTES                    128       /* blockref struct in bytes */
702 #define HAMMER2_BLOCKREF_RADIX                    7
703 
704 #define HAMMER2_BLOCKREF_LEAF_MAX       65535
705 
706 /*
707  * On-media and off-media blockref types.
708  *
709  * types >= 128 are pseudo values that should never be present on-media.
710  */
711 #define HAMMER2_BREF_TYPE_EMPTY                   0
712 #define HAMMER2_BREF_TYPE_INODE                   1
713 #define HAMMER2_BREF_TYPE_INDIRECT      2
714 #define HAMMER2_BREF_TYPE_DATA                    3
715 #define HAMMER2_BREF_TYPE_DIRENT        4
716 #define HAMMER2_BREF_TYPE_FREEMAP_NODE  5
717 #define HAMMER2_BREF_TYPE_FREEMAP_LEAF  6
718 #define HAMMER2_BREF_TYPE_INVALID       7
719 #define HAMMER2_BREF_TYPE_FREEMAP       254       /* pseudo-type */
720 #define HAMMER2_BREF_TYPE_VOLUME        255       /* pseudo-type */
721 
722 #define HAMMER2_BREF_FLAG_PFSROOT       0x01      /* see also related opflag */
723 #define HAMMER2_BREF_FLAG_UNUSED        0x02
724 #define HAMMER2_BREF_FLAG_EMERG_MIP     0x04      /* emerg modified-in-place */
725 
726 /*
727  * Check mode defaults to xxhash64.
728  */
729 #define HAMMER2_CHECK_NONE              0
730 #define HAMMER2_CHECK_DISABLED                    1
731 #define HAMMER2_CHECK_ISCSI32           2
732 #define HAMMER2_CHECK_XXHASH64                    3
733 #define HAMMER2_CHECK_SHA192            4
734 #define HAMMER2_CHECK_FREEMAP           5
735 
736 #define HAMMER2_CHECK_DEFAULT           HAMMER2_CHECK_XXHASH64
737 
738 /*
739  * Compression mode defaults to LZ4.
740  */
741 #define HAMMER2_COMP_NONE               0
742 #define HAMMER2_COMP_AUTOZERO           1
743 #define HAMMER2_COMP_LZ4                2
744 #define HAMMER2_COMP_ZLIB               3
745 
746 #define HAMMER2_COMP_DEFAULT            HAMMER2_COMP_LZ4
747 
748 /*
749  * Encode/decode check mode and compression mode for bref.methods.
750  * The compression level is not encoded in bref.methods.
751  */
752 #define HAMMER2_ENC_CHECK(n)            (((n) & 15) << 4)
753 #define HAMMER2_DEC_CHECK(n)            (((n) >> 4) & 15)
754 #define HAMMER2_ENC_COMP(n)             ((n) & 15)
755 #define HAMMER2_DEC_COMP(n)             ((n) & 15)
756 
757 /*
758  * Encode/decode check or compression algorithm request in
759  * ipdata->meta.check_algo and ipdata->meta.comp_algo.
760  */
761 #define HAMMER2_ENC_ALGO(n)             (n)
762 #define HAMMER2_DEC_ALGO(n)             ((n) & 15)
763 #define HAMMER2_ENC_LEVEL(n)            ((n) << 4)
764 #define HAMMER2_DEC_LEVEL(n)            (((n) >> 4) & 15)
765 
766 /*
767  * HAMMER2 block references are collected into sets of 4 blockrefs.  These
768  * sets are fully associative, meaning the elements making up a set may
769  * contain duplicate entries, holes, but valid elements are always sorted.
770  *
771  * When redundancy is desired a set may contain several duplicate
772  * entries pointing to different copies of the same data.  Up to 4 copies
773  * are supported. Not implemented.
774  *
775  * When a set fills up another level of indirection is inserted, moving
776  * some or all of the set's contents into indirect blocks placed under the
777  * set.  This is a top-down approach in that indirect blocks are not created
778  * until the set actually becomes full (that is, the entries in the set can
779  * shortcut the indirect blocks when the set is not full).  Depending on how
780  * things are filled multiple indirect blocks will eventually be created.
781  */
782 struct hammer2_blockset {
783           hammer2_blockref_t  blockref[HAMMER2_SET_COUNT];
784 };
785 
786 typedef struct hammer2_blockset hammer2_blockset_t;
787 
788 /*
789  * Catch programmer snafus
790  */
791 #if (1 << HAMMER2_SET_RADIX) != HAMMER2_SET_COUNT
792 #error "hammer2 direct radix is incorrect"
793 #endif
794 #if (1 << HAMMER2_PBUFRADIX) != HAMMER2_PBUFSIZE
795 #error "HAMMER2_PBUFRADIX and HAMMER2_PBUFSIZE are inconsistent"
796 #endif
797 #if (1 << HAMMER2_RADIX_MIN) != HAMMER2_ALLOC_MIN
798 #error "HAMMER2_RADIX_MIN and HAMMER2_ALLOC_MIN are inconsistent"
799 #endif
800 
801 /*
802  * hammer2_bmap_data - A freemap entry in the LEVEL1 block.
803  *
804  * Each 128-byte entry contains the bitmap and meta-data required to manage
805  * a LEVEL0 (4MB) block of storage.  The storage is managed in 256 x 16KB
806  * chunks.
807  *
808  * A smaller allocation granularity is supported via a linear iterator and/or
809  * must otherwise be tracked in ram.
810  *
811  * (data structure must be 128 bytes exactly)
812  *
813  * linear  - A BYTE linear allocation offset used for sub-16KB allocations
814  *             only.  May contain values between 0 and 4MB.  Must be ignored
815  *             if 16KB-aligned (i.e. force bitmap scan), otherwise may be
816  *             used to sub-allocate within the 16KB block (which is already
817  *             marked as allocated in the bitmap).
818  *
819  *             Sub-allocations need only be 1KB-aligned and do not have to be
820  *             size-aligned, and 16KB or larger allocations do not update this
821  *             field, resulting in pretty good packing.
822  *
823  *             Please note that file data granularity may be limited by
824  *             other issues such as buffer cache direct-mapping and the
825  *             desire to support sector sizes up to 16KB (so H2 only issues
826  *             I/O's in multiples of 16KB anyway).
827  *
828  * class   - Clustering class.  Cleared to 0 only if the entire leaf becomes
829  *             free.  Used to cluster device buffers so all elements must have
830  *             the same device block size, but may mix logical sizes.
831  *
832  *             Typically integrated with the blockref type in the upper 8 bits
833  *             to localize inodes and indrect blocks, improving bulk free scans
834  *             and directory scans.
835  *
836  * bitmap  - Two bits per 16KB allocation block arranged in arrays of
837  *             64-bit elements, 256x2 bits representing ~4MB worth of media
838  *             storage.  Bit patterns are as follows:
839  *
840  *             00   Unallocated
841  *             01 (reserved)
842  *             10 Possibly free
843  *           11 Allocated
844  *
845  * ==========
846  * level6 freemap
847  * blockref[0]       : 4EB
848  * blockref[1]       : 4EB
849  * blockref[2]       : 4EB
850  * blockref[3]       : 4EB
851  * -----------------------------------------------------------------------
852  * 4 x 128B = 512B   : 4 x 4EB = 16EB
853  *
854  * level2-5 FREEMAP_NODE
855  * blockref[0]       : 1GB,256GB,64TB,16PB
856  * blockref[1]       : 1GB,256GB,64TB,16PB
857  * ...
858  * blockref[255]     : 1GB,256GB,64TB,16PB
859  * -----------------------------------------------------------------------
860  * 256 x 128B = 32KB : 256 x 1GB,256GB,64TB,16PB = 256GB,64TB,16PB,4EB
861  *
862  * level1 FREEMAP_LEAF
863  * bmap_data[0]      : 8 x 8B = 512bits = 256 x 2bits -> 256 x 16KB = 4MB
864  * bmap_data[1]      : 8 x 8B = 512bits = 256 x 2bits -> 256 x 16KB = 4MB
865  * ...
866  * bmap_data[255]    : 8 x 8B = 512bits = 256 x 2bits -> 256 x 16KB = 4MB
867  * -----------------------------------------------------------------------
868  * 256 x 128B = 32KB : 256 x 4MB = 1GB
869  * ==========
870  */
871 struct hammer2_bmap_data {
872           int32_t linear;               /* 00 linear sub-granular allocation offset */
873           uint16_t class;               /* 04-05 clustering class ((type<<8)|radix) */
874           uint8_t reserved06; /* 06 */
875           uint8_t reserved07; /* 07 */
876           uint32_t reserved08;          /* 08 */
877           uint32_t reserved0C;          /* 0C */
878           uint32_t reserved10;          /* 10 */
879           uint32_t reserved14;          /* 14 */
880           uint32_t reserved18;          /* 18 */
881           uint32_t avail;               /* 1C */
882           uint32_t reserved20[8];       /* 20-3F */
883                                         /* 40-7F 512 bits manages 4MB of storage */
884           hammer2_bitmap_t bitmapq[HAMMER2_BMAP_ELEMENTS];
885 } __packed;
886 
887 typedef struct hammer2_bmap_data hammer2_bmap_data_t;
888 
889 /*
890  * The inode number is stored in the inode rather than being
891  * based on the location of the inode (since the location moves every time
892  * the inode or anything underneath the inode is modified).
893  *
894  * The inode is 1024 bytes, made up of 256 bytes of meta-data, 256 bytes
895  * for the filename, and 512 bytes worth of direct file data OR an embedded
896  * blockset.  The in-memory hammer2_inode structure contains only the mostly-
897  * node-independent meta-data portion (some flags are node-specific and will
898  * not be synchronized).  The rest of the inode is node-specific and chain I/O
899  * is required to obtain it.
900  *
901  * Directories represent one inode per blockref.  Inodes are not laid out
902  * as a file but instead are represented by the related blockrefs.  The
903  * blockrefs, in turn, are indexed by the 64-bit directory hash key.  Remember
904  * that blocksets are fully associative, so a certain degree efficiency is
905  * achieved just from that.
906  *
907  * Up to 512 bytes of direct data can be embedded in an inode, and since
908  * inodes are essentially directory entries this also means that small data
909  * files end up simply being laid out linearly in the directory, resulting
910  * in fewer seeks and highly optimal access.
911  *
912  * The compression mode can be changed at any time in the inode and is
913  * recorded on a blockref-by-blockref basis.
914  */
915 #define HAMMER2_INODE_BYTES             1024      /* (asserted by code) */
916 #define HAMMER2_INODE_MAXNAME           256       /* maximum name in bytes */
917 #define HAMMER2_INODE_VERSION_ONE       1
918 
919 #define HAMMER2_INODE_START             1024      /* dynamically allocated */
920 
921 struct hammer2_inode_meta {
922           uint16_t  version;  /* 0000 inode data version */
923           uint8_t             reserved02;         /* 0002 */
924           uint8_t             pfs_subtype;        /* 0003 pfs sub-type */
925 
926           /*
927            * core inode attributes, inode type, misc flags
928            */
929           uint32_t  uflags;             /* 0004 chflags */
930           uint32_t  rmajor;             /* 0008 available for device nodes */
931           uint32_t  rminor;             /* 000C available for device nodes */
932           uint64_t  ctime;              /* 0010 inode change time */
933           uint64_t  mtime;              /* 0018 modified time */
934           uint64_t  atime;              /* 0020 access time (unsupported) */
935           uint64_t  btime;              /* 0028 birth time */
936           uuid_t              uid;                /* 0030 uid / degenerate unix uid */
937           uuid_t              gid;                /* 0040 gid / degenerate unix gid */
938 
939           uint8_t             type;               /* 0050 object type */
940           uint8_t             op_flags; /* 0051 operational flags */
941           uint16_t  cap_flags;          /* 0052 capability flags */
942           uint32_t  mode;               /* 0054 unix modes (typ low 16 bits) */
943 
944           /*
945            * inode size, identification, localized recursive configuration
946            * for compression and backup copies.
947            *
948            * NOTE: Nominal parent inode number (iparent) is only applicable
949            *         for directories but can also help for files during
950            *         catastrophic recovery.
951            */
952           hammer2_tid_t       inum;               /* 0058 inode number */
953           hammer2_off_t       size;               /* 0060 size of file */
954           uint64_t  nlinks;             /* 0068 hard links (typ only dirs) */
955           hammer2_tid_t       iparent;  /* 0070 nominal parent inum */
956           hammer2_key_t       name_key; /* 0078 full filename key */
957           uint16_t  name_len; /* 0080 filename length */
958           uint8_t             ncopies;  /* 0082 ncopies to local media */
959           uint8_t             comp_algo;          /* 0083 compression request & algo */
960           uint8_t             unused84; /* 0084 */
961           uint8_t             check_algo;         /* 0085 check code request & algo */
962 
963           /*
964            * These fields are currently only applicable to PFSROOTs.
965            *
966            * NOTE: We can't use {volume_data->fsid, pfs_clid} to uniquely
967            *         identify an instance of a PFS in the cluster because
968            *         a mount may contain more than one copy of the PFS as
969            *         a separate node.  {pfs_clid, pfs_fsid} must be used for
970            *         registration in the cluster.
971            */
972           uint8_t             pfs_nmasters;       /* 0086 (if PFSROOT) if multi-master */
973           uint8_t             pfs_type; /* 0087 (if PFSROOT) node type */
974           hammer2_tid_t       pfs_inum; /* 0088 (if PFSROOT) inum allocator */
975           uuid_t              pfs_clid; /* 0090 (if PFSROOT) cluster uuid */
976           uuid_t              pfs_fsid; /* 00A0 (if PFSROOT) unique uuid */
977 
978           /*
979            * Quotas and aggregate sub-tree inode and data counters.  Note that
980            * quotas are not replicated downward, they are explicitly set by
981            * the sysop and in-memory structures keep track of inheritance.
982            */
983           hammer2_key_t       data_quota;         /* 00B0 subtree quota in bytes */
984           hammer2_key_t       unusedB8; /* 00B8 */
985           hammer2_key_t       inode_quota;        /* 00C0 subtree quota inode count */
986           hammer2_key_t       unusedC8; /* 00C8 */
987 
988           /*
989            * The last snapshot tid is tested against modify_tid to determine
990            * when a copy must be made of a data block whos check mode has been
991            * disabled (a disabled check mode allows data blocks to be updated
992            * in place instead of copy-on-write).
993            */
994           hammer2_tid_t       pfs_lsnap_tid;      /* 00D0 last snapshot tid */
995           hammer2_tid_t       reservedD8;         /* 00D8 (avail) */
996 
997           /*
998            * Tracks (possibly degenerate) free areas covering all sub-tree
999            * allocations under inode, not counting the inode itself.
1000            * 0/0 indicates empty entry.  fully set-associative.
1001            *
1002            * (not yet implemented)
1003            */
1004           uint64_t  decrypt_check;      /* 00E0 decryption validator */
1005           hammer2_off_t       reservedE8[3];      /* 00E8/F0/F8 */
1006 } __packed;
1007 
1008 typedef struct hammer2_inode_meta hammer2_inode_meta_t;
1009 
1010 struct hammer2_inode_data {
1011           hammer2_inode_meta_t          meta;     /* 0000-00FF */
1012           unsigned char       filename[HAMMER2_INODE_MAXNAME];
1013                                                   /* 0100-01FF (256 char, unterminated) */
1014           union {                                 /* 0200-03FF (64x8 = 512 bytes) */
1015                     hammer2_blockset_t blockset;
1016                     char data[HAMMER2_EMBEDDED_BYTES];
1017           } u;
1018 } __packed;
1019 
1020 typedef struct hammer2_inode_data hammer2_inode_data_t;
1021 
1022 #define HAMMER2_OPFLAG_DIRECTDATA       0x01
1023 #define HAMMER2_OPFLAG_PFSROOT                    0x02      /* (see also bref flag) */
1024 #define HAMMER2_OPFLAG_COPYIDS                    0x04      /* copyids override parent */
1025 
1026 #define HAMMER2_OBJTYPE_UNKNOWN                   0
1027 #define HAMMER2_OBJTYPE_DIRECTORY       1
1028 #define HAMMER2_OBJTYPE_REGFILE                   2
1029 #define HAMMER2_OBJTYPE_FIFO            4
1030 #define HAMMER2_OBJTYPE_CDEV            5
1031 #define HAMMER2_OBJTYPE_BDEV            6
1032 #define HAMMER2_OBJTYPE_SOFTLINK        7
1033 #define HAMMER2_OBJTYPE_UNUSED08        8
1034 #define HAMMER2_OBJTYPE_SOCKET                    9
1035 #define HAMMER2_OBJTYPE_WHITEOUT        10
1036 
1037 #define HAMMER2_COPYID_NONE             0
1038 #define HAMMER2_COPYID_LOCAL            ((uint8_t)-1)
1039 
1040 #define HAMMER2_COPYID_COUNT            256
1041 
1042 /*
1043  * PFS types identify the role of a PFS within a cluster.  The PFS types
1044  * is stored on media and in LNK_SPAN messages and used in other places.
1045  *
1046  * The low 4 bits specify the current active type while the high 4 bits
1047  * specify the transition target if the PFS is being upgraded or downgraded,
1048  * If the upper 4 bits are not zero it may effect how a PFS is used during
1049  * the transition.
1050  *
1051  * Generally speaking, downgrading a MASTER to a SLAVE cannot complete until
1052  * at least all MASTERs have updated their pfs_nmasters field.  And upgrading
1053  * a SLAVE to a MASTER cannot complete until the new prospective master has
1054  * been fully synchronized (though theoretically full synchronization is
1055  * not required if a (new) quorum of other masters are fully synchronized).
1056  *
1057  * It generally does not matter which PFS element you actually mount, you
1058  * are mounting 'the cluster'.  So, for example, a network mount will mount
1059  * a DUMMY PFS type on a memory filesystem.  However, there are two exceptions.
1060  * In order to gain the benefits of a SOFT_MASTER or SOFT_SLAVE, those PFSs
1061  * must be directly mounted.
1062  */
1063 #define HAMMER2_PFSTYPE_NONE            0x00
1064 #define HAMMER2_PFSTYPE_CACHE           0x01
1065 #define HAMMER2_PFSTYPE_UNUSED02        0x02
1066 #define HAMMER2_PFSTYPE_SLAVE           0x03
1067 #define HAMMER2_PFSTYPE_SOFT_SLAVE      0x04
1068 #define HAMMER2_PFSTYPE_SOFT_MASTER     0x05
1069 #define HAMMER2_PFSTYPE_MASTER                    0x06
1070 #define HAMMER2_PFSTYPE_UNUSED07        0x07
1071 #define HAMMER2_PFSTYPE_SUPROOT                   0x08
1072 #define HAMMER2_PFSTYPE_DUMMY           0x09
1073 #define HAMMER2_PFSTYPE_MAX             16
1074 
1075 #define HAMMER2_PFSTRAN_NONE            0x00      /* no transition in progress */
1076 #define HAMMER2_PFSTRAN_CACHE           0x10
1077 #define HAMMER2_PFSTRAN_UNUSED20        0x20
1078 #define HAMMER2_PFSTRAN_SLAVE           0x30
1079 #define HAMMER2_PFSTRAN_SOFT_SLAVE      0x40
1080 #define HAMMER2_PFSTRAN_SOFT_MASTER     0x50
1081 #define HAMMER2_PFSTRAN_MASTER                    0x60
1082 #define HAMMER2_PFSTRAN_UNUSED70        0x70
1083 #define HAMMER2_PFSTRAN_SUPROOT                   0x80
1084 #define HAMMER2_PFSTRAN_DUMMY           0x90
1085 
1086 #define HAMMER2_PFS_DEC(n)              ((n) & 0x0F)
1087 #define HAMMER2_PFS_DEC_TRANSITION(n)   (((n) >> 4) & 0x0F)
1088 #define HAMMER2_PFS_ENC_TRANSITION(n)   (((n) & 0x0F) << 4)
1089 
1090 #define HAMMER2_PFSSUBTYPE_NONE                   0
1091 #define HAMMER2_PFSSUBTYPE_SNAPSHOT     1         /* manual/managed snapshot */
1092 #define HAMMER2_PFSSUBTYPE_AUTOSNAP     2         /* automatic snapshot */
1093 
1094 /*
1095  * PFS mode of operation is a bitmask.  This is typically not stored
1096  * on-media, but defined here because the field may be used in dmsgs.
1097  */
1098 #define HAMMER2_PFSMODE_QUORUM                    0x01
1099 #define HAMMER2_PFSMODE_RW              0x02
1100 
1101 /*
1102  * The volume header eats a 64K block at the beginning of each 2GB zone
1103  * up to four copies.
1104  *
1105  * All information is stored in host byte order.  The volume header's magic
1106  * number may be checked to determine the byte order.  If you wish to mount
1107  * between machines w/ different endian modes you'll need filesystem code
1108  * which acts on the media data consistently (either all one way or all the
1109  * other).  Our code currently does not do that.
1110  *
1111  * A read-write mount may have to recover missing allocations by doing an
1112  * incremental mirror scan looking for modifications made after alloc_tid.
1113  * If alloc_tid == last_tid then no recovery operation is needed.  Recovery
1114  * operations are usually very, very fast.
1115  *
1116  * Read-only mounts do not need to do any recovery, access to the filesystem
1117  * topology is always consistent after a crash (is always consistent, period).
1118  * However, there may be shortcutted blockref updates present from deep in
1119  * the tree which are stored in the volumeh eader and must be tracked on
1120  * the fly.
1121  *
1122  * NOTE: The copyinfo[] array contains the configuration for both the
1123  *         cluster connections and any local media copies.  The volume
1124  *         header will be replicated for each local media copy.
1125  *
1126  *         The mount command may specify multiple medias or just one and
1127  *         allow HAMMER2 to pick up the others when it checks the copyinfo[]
1128  *         array on mount.
1129  *
1130  * NOTE: sroot_blockset points to the super-root directory, not the root
1131  *         directory.  The root directory will be a subdirectory under the
1132  *         super-root.
1133  *
1134  *         The super-root directory contains all root directories and all
1135  *         snapshots (readonly or writable).  It is possible to do a
1136  *         null-mount of the super-root using special path constructions
1137  *         relative to your mounted root.
1138  */
1139 #define HAMMER2_VOLUME_ID_HBO 0x48414d3205172011LLU
1140 #define HAMMER2_VOLUME_ID_ABO 0x11201705324d4148LLU
1141 
1142 /*
1143  * If volume version is HAMMER2_VOL_VERSION_MULTI_VOLUMES or above, max
1144  * HAMMER2_MAX_VOLUMES volumes are supported. There must be 1 (and only 1)
1145  * volume with volume id HAMMER2_ROOT_VOLUME.
1146  * Otherwise filesystem only supports 1 volume, and that volume must have
1147  * volume id HAMMER2_ROOT_VOLUME(0) which was a reserved field then.
1148  */
1149 #define HAMMER2_MAX_VOLUMES   64
1150 #define HAMMER2_ROOT_VOLUME   0
1151 
1152 struct hammer2_volume_data {
1153           /*
1154            * sector #0 - 512 bytes
1155            */
1156           uint64_t  magic;                        /* 0000 Signature */
1157           hammer2_off_t       boot_beg;           /* 0008 Boot area (future) */
1158           hammer2_off_t       boot_end;           /* 0010 (size = end - beg) */
1159           hammer2_off_t       aux_beg;            /* 0018 Aux area (future) */
1160           hammer2_off_t       aux_end;            /* 0020 (size = end - beg) */
1161           hammer2_off_t       volu_size;                    /* 0028 Volume size, bytes */
1162 
1163           uint32_t  version;            /* 0030 */
1164           uint32_t  flags;                        /* 0034 */
1165           uint8_t             copyid;                       /* 0038 copyid of phys vol */
1166           uint8_t             freemap_version;    /* 0039 freemap algorithm */
1167           uint8_t             peer_type;                    /* 003A HAMMER2_PEER_xxx */
1168           uint8_t             volu_id;            /* 003B */
1169           uint8_t             nvolumes;           /* 003C */
1170           uint8_t             reserved003D;                 /* 003D */
1171           uint16_t  reserved003E;                 /* 003E */
1172 
1173           uuid_t              fsid;                         /* 0040 */
1174           uuid_t              fstype;                       /* 0050 */
1175 
1176           /*
1177            * allocator_size is precalculated at newfs time and does not include
1178            * reserved blocks, boot, or aux areas.
1179            *
1180            * Initial non-reserved-area allocations do not use the freemap
1181            * but instead adjust alloc_iterator.  Dynamic allocations take
1182            * over starting at (allocator_beg).  This makes newfs_hammer2's
1183            * job a lot easier and can also serve as a testing jig.
1184            */
1185           hammer2_off_t       allocator_size;               /* 0060 Total data space */
1186           hammer2_off_t   allocator_free;                   /* 0068   Free space */
1187           hammer2_off_t       allocator_beg;                /* 0070 Initial allocations */
1188 
1189           /*
1190            * mirror_tid reflects the highest committed change for this
1191            * block device regardless of whether it is to the super-root
1192            * or to a PFS or whatever.
1193            *
1194            * freemap_tid reflects the highest committed freemap change for
1195            * this block device.
1196            */
1197           hammer2_tid_t       mirror_tid;                   /* 0078 committed tid (vol) */
1198           hammer2_tid_t       reserved0080;                 /* 0080 */
1199           hammer2_tid_t       reserved0088;                 /* 0088 */
1200           hammer2_tid_t       freemap_tid;                  /* 0090 committed tid (fmap) */
1201           hammer2_tid_t       bulkfree_tid;                 /* 0098 bulkfree incremental */
1202           hammer2_tid_t       reserved00A0[4];    /* 00A0-00BF */
1203 
1204           hammer2_off_t       total_size;                   /* 00C0 Total volume size, bytes */
1205 
1206           /*
1207            * Copyids are allocated dynamically from the copyexists bitmap.
1208            * An id from the active copies set (up to 8, see copyinfo later on)
1209            * may still exist after the copy set has been removed from the
1210            * volume header and its bit will remain active in the bitmap and
1211            * cannot be reused until it is 100% removed from the hierarchy.
1212            */
1213           uint32_t  copyexists[8];                /* 00C8-00E7 copy exists bmap */
1214           char                reserved00E8[248];  /* 00E8-01DF */
1215 
1216           /*
1217            * 32 bit CRC array at the end of the first 512 byte sector.
1218            *
1219            * icrc_sects[7] - First 512-4 bytes of volume header (including all
1220            *                     the other icrc's except this one).
1221            *
1222            * icrc_sects[6] - Sector 1 (512 bytes) of volume header, which is
1223            *                     the blockset for the root.
1224            *
1225            * icrc_sects[5] - Sector 2
1226            * icrc_sects[4] - Sector 3
1227            * icrc_sects[3] - Sector 4 (the freemap blockset)
1228            */
1229           hammer2_crc32_t     icrc_sects[8];                /* 01E0-01FF */
1230 
1231           /*
1232            * sector #1 - 512 bytes
1233            *
1234            * The entire sector is used by a blockset, but currently only first
1235            * blockref is used.
1236            */
1237           hammer2_blockset_t sroot_blockset;      /* 0200-03FF Superroot dir */
1238 
1239           /*
1240            * sector #2-6
1241            */
1242           char      sector2[512];                           /* 0400-05FF reserved */
1243           char      sector3[512];                           /* 0600-07FF reserved */
1244           hammer2_blockset_t freemap_blockset;    /* 0800-09FF freemap  */
1245           char      sector5[512];                           /* 0A00-0BFF reserved */
1246           char      sector6[512];                           /* 0C00-0DFF reserved */
1247 
1248           /*
1249            * sector #7 - 512 bytes
1250            * Maximum 64 volume offsets within logical offset.
1251            */
1252           hammer2_off_t volu_loff[HAMMER2_MAX_VOLUMES];
1253 
1254           /*
1255            * sector #8-71     - 32768 bytes
1256            *
1257            * Contains the configuration for up to 256 copyinfo targets.  These
1258            * specify local and remote copies operating as masters or slaves.
1259            * copyid's 0 and 255 are reserved (0 indicates an empty slot and 255
1260            * indicates the local media).
1261            */
1262                                                             /* 1000-8FFF copyinfo config */
1263           hammer2_volconf_t copyinfo[HAMMER2_COPYID_COUNT];
1264 
1265           /*
1266            * Remaining sections are reserved for future use.
1267            */
1268           char                reserved9000[0x6FFC];         /* 9000-FFFB reserved */
1269 
1270           /*
1271            * icrc on entire volume header
1272            */
1273           hammer2_crc32_t     icrc_volheader;               /* FFFC-FFFF full volume icrc*/
1274 } __packed;
1275 
1276 typedef struct hammer2_volume_data hammer2_volume_data_t;
1277 
1278 /*
1279  * Various parts of the volume header have their own iCRCs.
1280  *
1281  * The first 512 bytes has its own iCRC stored at the end of the 512 bytes
1282  * and not included the icrc calculation.
1283  *
1284  * The second 512 bytes also has its own iCRC but it is stored in the first
1285  * 512 bytes so it covers the entire second 512 bytes.
1286  *
1287  * The whole volume block (64KB) has an iCRC covering all but the last 4 bytes,
1288  * which is where the iCRC for the whole volume is stored.  This is currently
1289  * a catch-all for anything not individually iCRCd.
1290  */
1291 #define HAMMER2_VOL_ICRC_SECT0                    7
1292 #define HAMMER2_VOL_ICRC_SECT1                    6
1293 
1294 #define HAMMER2_VOLUME_BYTES            65536
1295 
1296 #define HAMMER2_VOLUME_ICRC0_OFF        0
1297 #define HAMMER2_VOLUME_ICRC1_OFF        512
1298 #define HAMMER2_VOLUME_ICRCVH_OFF       0
1299 
1300 #define HAMMER2_VOLUME_ICRC0_SIZE       (512 - 4)
1301 #define HAMMER2_VOLUME_ICRC1_SIZE       (512)
1302 #define HAMMER2_VOLUME_ICRCVH_SIZE      (65536 - 4)
1303 
1304 #define HAMMER2_VOL_VERSION_MULTI_VOLUMES         2
1305 
1306 #define HAMMER2_VOL_VERSION_MIN                   1
1307 #define HAMMER2_VOL_VERSION_DEFAULT     HAMMER2_VOL_VERSION_MULTI_VOLUMES
1308 #define HAMMER2_VOL_VERSION_WIP                   (HAMMER2_VOL_VERSION_MULTI_VOLUMES + 1)
1309 
1310 #define HAMMER2_NUM_VOLHDRS             4
1311 
1312 union hammer2_media_data {
1313           hammer2_volume_data_t         voldata;
1314         hammer2_inode_data_t    ipdata;
1315           hammer2_blockset_t  blkset;
1316           hammer2_blockref_t  npdata[HAMMER2_IND_COUNT_MAX];
1317           hammer2_bmap_data_t bmdata[HAMMER2_FREEMAP_COUNT];
1318           char                          buf[HAMMER2_PBUFSIZE];
1319 } __packed;
1320 
1321 typedef union hammer2_media_data hammer2_media_data_t;
1322 
1323 #endif /* !_VFS_HAMMER2_DISK_H_ */
1324