1 typedef struct Arch Arch;
2 typedef struct BList BList;
3 typedef struct Block Block;
4 typedef struct Cache Cache;
5 typedef struct Disk Disk;
6 typedef struct Entry Entry;
7 typedef struct Fsck Fsck;
8 typedef struct Header Header;
9 typedef struct Label Label;
10 typedef struct Periodic Periodic;
11 typedef struct Snap Snap;
12 typedef struct Source Source;
13 typedef struct Super Super;
14 typedef struct WalkPtr WalkPtr;
15 
16 #pragma incomplete Arch
17 #pragma incomplete BList
18 #pragma incomplete Cache
19 #pragma incomplete Disk
20 #pragma incomplete Periodic
21 #pragma incomplete Snap
22 
23 /* tunable parameters - probably should not be constants */
24 enum {
25 	/*
26 	 * estimate of bytes per dir entries - determines number
27 	 * of index entries in the block
28 	 */
29 	BytesPerEntry = 100,
30 	/* don't allocate in block if more than this percentage full */
31 	FullPercentage = 80,
32 	FlushSize = 200,	/* number of blocks to flush */
33 	DirtyPercentage = 50,	/* maximum percentage of dirty blocks */
34 };
35 
36 enum {
37 	Nowaitlock,
38 	Waitlock,
39 
40 	MaxBlock	= (1UL<<31),
41 };
42 
43 enum {
44 	HeaderMagic = 0x3776ae89,
45 	HeaderVersion = 1,
46 	HeaderOffset = 128*1024,
47 	HeaderSize = 512,
48 	SuperMagic = 0x2340a3b1,
49 	SuperSize = 512,
50 	SuperVersion = 1,
51 	LabelSize = 14,
52 };
53 
54 /* well known tags */
55 enum {
56 	BadTag = 0,		/* this tag should not be used */
57 	RootTag = 1,		/* root of fs */
58 	EnumTag,		/* root of a dir listing */
59 	UserTag = 32,		/* all other tags should be >= UserTag */
60 };
61 
62 struct Super {
63 	u16int version;
64 	u32int epochLow;
65 	u32int epochHigh;
66 	u64int qid;			/* next qid */
67 	u32int active;			/* root of active file system */
68 	u32int next;			/* root of next snapshot to archive */
69 	u32int current;			/* root of snapshot currently archiving */
70 	uchar last[VtScoreSize];	/* last snapshot successfully archived */
71 	char name[128];			/* label */
72 };
73 
74 
75 struct Fs {
76 	Arch	*arch;		/* immutable */
77 	Cache	*cache;		/* immutable */
78 	int	mode;		/* immutable */
79 	int	noatimeupd;	/* immutable */
80 	int	blockSize;	/* immutable */
81 	VtConn *z;		/* immutable */
82 	Snap	*snap;		/* immutable */
83 	/* immutable; copy here & Fsys to ease error reporting */
84 	char	*name;
85 
86 	Periodic *metaFlush; /* periodically flushes metadata cached in files */
87 
88 	/*
89 	 * epoch lock.
90 	 * Most operations on the fs require a read lock of elk, ensuring that
91 	 * the current high and low epochs do not change under foot.
92 	 * This lock is mostly acquired via a call to fileLock or fileRlock.
93 	 * Deletion and creation of snapshots occurs under a write lock of elk,
94 	 * ensuring no file operations are occurring concurrently.
95 	 */
96 	RWLock	elk;		/* epoch lock */
97 	u32int	ehi;		/* epoch high */
98 	u32int	elo;		/* epoch low */
99 
100 	int	halted;	/* epoch lock is held to halt (console initiated) */
101 
102 	Source	*source;	/* immutable: root of sources */
103 	File	*file;		/* immutable: root of files */
104 };
105 
106 /*
107  * variant on VtEntry
108  * there are extra fields when stored locally
109  */
110 struct Entry {
111 	u32int	gen;			/* generation number */
112 	ushort	psize;			/* pointer block size */
113 	ushort	dsize;			/* data block size */
114 	uchar	depth;			/* unpacked from flags */
115 	uchar	flags;
116 	uvlong	size;
117 	uchar	score[VtScoreSize];
118 	u32int	tag;	/* tag for local blocks: zero if stored on Venti */
119 	u32int	snap;	/* non-zero -> entering snapshot of given epoch */
120 	uchar	archive; /* archive this snapshot: only valid for snap != 0 */
121 };
122 
123 /*
124  * This is called a `stream' in the fossil paper.  There used to be Sinks too.
125  * We believe that Sources and Files are one-to-one.
126  */
127 struct Source {
128 	Fs	*fs;		/* immutable */
129 	int	mode;		/* immutable */
130 	int	issnapshot;	/* immutable */
131 	u32int	gen;		/* immutable */
132 	int	dsize;		/* immutable */
133 	int	dir;		/* immutable */
134 
135 	Source	*parent;	/* immutable */
136 	File	*file;		/* immutable; point back */
137 
138 	QLock	lk;
139 	int	ref;
140 	/*
141 	 * epoch for the source
142 	 * for ReadWrite sources, epoch is used to lazily notice
143 	 * sources that must be split from the snapshots.
144 	 * for ReadOnly sources, the epoch represents the minimum epoch
145 	 * along the chain from the root, and is used to lazily notice
146 	 * sources that have become invalid because they belong to an old
147 	 * snapshot.
148 	 */
149 	u32int	epoch;
150 	Block	*b;		/* block containing this source */
151 	uchar	score[VtScoreSize]; /* score of block containing this source */
152 	u32int	scoreEpoch;	/* epoch of block containing this source */
153 	int	epb;		/* immutable: entries per block in parent */
154 	u32int	tag;		/* immutable: tag of parent */
155 	u32int	offset; 	/* immutable: entry offset in parent */
156 };
157 
158 
159 struct Header {
160 	ushort version;
161 	ushort blockSize;
162 	ulong super;	/* super blocks */
163 	ulong label;	/* start of labels */
164 	ulong data;	/* end of labels - start of data blocks */
165 	ulong end;	/* end of data blocks */
166 };
167 
168 /*
169  * contains a one block buffer
170  * to avoid problems of the block changing underfoot
171  * and to enable an interface that supports unget.
172  */
173 struct DirEntryEnum {
174 	File	*file;
175 
176 	u32int	boff; 		/* block offset */
177 
178 	int	i, n;
179 	DirEntry *buf;
180 };
181 
182 /* Block states */
183 enum {
184 	BsFree = 0,		/* available for allocation */
185 	BsBad = 0xFF,		/* something is wrong with this block */
186 
187 	/* bit fields */
188 	BsAlloc = 1<<0,	/* block is in use */
189 	BsCopied = 1<<1,/* block has been copied (usually in preparation for unlink) */
190 	BsVenti = 1<<2,	/* block has been stored on Venti */
191 	BsClosed = 1<<3,/* block has been unlinked on disk from active file system */
192 	BsMask = BsAlloc|BsCopied|BsVenti|BsClosed,
193 };
194 
195 /*
196  * block types
197  * more regular than Venti block types
198  * bit 3 -> block or data block
199  * bits 2-0 -> level of block
200  */
201 enum {
202 	BtData,
203 	BtDir = 1<<3,
204 	BtLevelMask = 7,
205 	BtMax = 1<<4,
206 };
207 
208 /* io states */
209 enum {
210 	BioEmpty,	/* label & data are not valid */
211 	BioLabel,	/* label is good */
212 	BioClean,	/* data is on the disk */
213 	BioDirty,	/* data is not yet on the disk */
214 	BioReading,	/* in process of reading data */
215 	BioWriting,	/* in process of writing data */
216 	BioReadError,	/* error reading: assume disk always handles write errors */
217 	BioVentiError,	/* error reading from venti (probably disconnected) */
218 	BioMax
219 };
220 
221 struct Label {
222 	uchar type;
223 	uchar state;
224 	u32int tag;
225 	u32int epoch;
226 	u32int epochClose;
227 };
228 
229 struct Block {
230 	Cache	*c;
231 	int	ref;
232 	int	nlock;
233 	uintptr	pc;		/* pc that fetched this block from the cache */
234 
235 	QLock	lk;
236 
237 	int 	part;
238 	u32int	addr;
239 	uchar	score[VtScoreSize];	/* score */
240 	Label	l;
241 
242 	uchar	*dmap;
243 
244 	uchar 	*data;
245 
246 	/* the following is private; used by cache */
247 
248 	Block	*next;			/* doubly linked hash chains */
249 	Block	**prev;
250 	u32int	heap;			/* index in heap table */
251 	u32int	used;			/* last reference times */
252 
253 	u32int	vers;			/* version of dirty flag */
254 
255 	BList	*uhead;	/* blocks to unlink when this block is written */
256 	BList	*utail;
257 
258 	/* block ordering for cache -> disk */
259 	BList	*prior;			/* list of blocks before this one */
260 
261 	Block	*ionext;
262 	int	iostate;
263 	Rendez	ioready;
264 };
265 
266 /* tree walker, for gc and archiver */
267 struct WalkPtr
268 {
269 	uchar	*data;
270 	int	isEntry;
271 	int	n;
272 	int	m;
273 	Entry	e;
274 	uchar	type;
275 	u32int	tag;
276 };
277 
278 enum
279 {
280 	DoClose = 1<<0,
281 	DoClre = 1<<1,
282 	DoClri = 1<<2,
283 	DoClrp = 1<<3,
284 };
285 
286 struct Fsck
287 {
288 	/* filled in by caller */
289 	int	printblocks;
290 	int	useventi;
291 	int	flags;
292 	int	printdirs;
293 	int	printfiles;
294 	int	walksnapshots;
295 	int	walkfs;
296 	Fs	*fs;
297 	int	(*print)(char*, ...);
298 	void	(*clre)(Fsck*, Block*, int);
299 	void	(*clrp)(Fsck*, Block*, int);
300 	void	(*close)(Fsck*, Block*, u32int);
301 	void	(*clri)(Fsck*, char*, MetaBlock*, int, Block*);
302 
303 	/* used internally */
304 	Cache	*cache;
305 	uchar	*amap;	/* all blocks seen so far */
306 	uchar	*emap;	/* all blocks seen in this epoch */
307 	uchar	*xmap;	/* all blocks in this epoch with parents in this epoch */
308 	uchar	*errmap;	/* blocks with errors */
309 	uchar	*smap;		/* walked sources */
310 	int	nblocks;
311 	int	bsize;
312 	int	walkdepth;
313 	u32int	hint;		/* where the next root probably is */
314 	int	nseen;
315 	int	quantum;
316 	int	nclre;
317 	int	nclrp;
318 	int	nclose;
319 	int	nclri;
320 };
321 
322 /* disk partitions; keep in sync with partname[] in disk.c */
323 enum {
324 	PartError,
325 	PartSuper,
326 	PartLabel,
327 	PartData,
328 	PartVenti,	/* fake partition */
329 };
330 
331 extern int vtType[BtMax];