xref: /inferno-os/liblogfs/replace.c (revision c094a1409b780cc543c077e8469fdb28b4c90afb)
1 #include "lib9.h"
2 #include "logfs.h"
3 #include "local.h"
4 #include "fcall.h"
5 
6 static char *
7 copypages(LogfsServer *server, long newb, long oldb, ulong copymask, LogfsLowLevelReadResult *llrrp, int *markedbadp)
8 {
9 	char *errmsg;
10 	int page;
11 	LogfsLowLevel *ll;
12 	int ppb;
13 	int pagesize;
14 	uchar *buf;
15 
16 	if(copymask == 0)
17 		return nil;
18 
19 	ll = server->ll;
20 	ppb = 1 << ll->l2pagesperblock;
21 	pagesize = 1 << ll->l2pagesize;
22 	*markedbadp = 0;
23 	*llrrp = LogfsLowLevelReadResultOk;
24 	errmsg = nil;
25 
26 	buf = logfsrealloc(nil, 1 << ll->l2pagesize);
27 	if(buf == nil)
28 		return Enomem;
29 
30 	for(page = ppb - 1; page >= 0; page--) {
31 		ulong m;
32 
33 		m = logfsdatapagemask(1, page);
34 
35 		if(copymask & m) {
36 			LogfsLowLevelReadResult llrr;
37 			if(server->trace > 1)
38 				print("copypages read page %d\n", page);
39 			errmsg = (*ll->readpagerange)(ll, buf, oldb, page, 0, pagesize, &llrr);
40 			if(errmsg != nil)
41 				break;
42 			if(llrr > *llrrp)
43 				*llrrp = llrr;
44 			if(server->trace > 1)
45 				print("copypages write page %d\n", page);
46 			errmsg = (*ll->writepage)(ll, buf, newb, page);
47 			if(errmsg) {
48 				if(strcmp(errmsg, Eio) == 0) {
49 					(*ll->markblockbad)(ll, newb);
50 					*markedbadp = 1;
51 				}
52 				break;
53 			}
54 			if(server->trace > 1)
55 				print("copypages end page %d\n", page);
56 		}
57 	}
58 	logfsfreemem(buf);
59 	return errmsg;
60 }
61 
62 char *
63 logfsservercopyactivedata(LogfsServer *server, long newb, long oldblockindex, int forcepage0, LogfsLowLevelReadResult *llrrp, int *markedbadp)
64 {
65 	LogfsLowLevel *ll = server->ll;
66 	ulong newpath;
67 	DataBlock *ob;
68 	char *errmsg;
69 
70 	ob = server->datablock + oldblockindex;
71 	if(forcepage0) {
72 		u32int mask;
73 		mask = logfsdatapagemask(1, 0);
74 		if(ob->free & mask) {
75 			ob->dirty |= mask;
76 			ob->free |= mask;
77 		}
78 	}
79 	if(server->trace > 1)
80 		print("copyactivedata %ld: (%ld -> %ld)\n", oldblockindex, ob->block, newb);
81 	newpath = mkdatapath(dataseqof(ob->path), copygensucc(copygenof(ob->path)));
82 	(*ll->setblocktag)(ll, newb, LogfsTdata);
83 	(*ll->setblockpath)(ll, newb, newpath);
84 	errmsg = copypages(server, newb, ob->block, ~ob->free, llrrp, markedbadp);
85 	if(errmsg)
86 		return errmsg;
87 	/*
88 	 * anything dirty and free is now not dirty and free
89 	 */
90 	ob->dirty &= ~(ob->dirty & ob->free);
91 	ob->block = newb;
92 	ob->path = newpath;
93 	return nil;
94 }
95 
96 /*
97  * unconditionally replace a datablock, and mark the old one bad
98  * NB: if page 0 is apparently unused, force it to be copied, and mark
99  * it free and dirty afterwards
100  */
101 char *
102 logfsserverreplacedatablock(LogfsServer *server, long index)
103 {
104 	long newb;
105 	LogfsLowLevel *ll = server->ll;
106 
107 	newb = logfsfindfreeblock(ll, AllocReasonReplace);
108 	/* TODO - recover space by scavenging other blocks, or recycling the log */
109 	while(newb >= 0) {
110 		char *errmsg;
111 		LogfsLowLevelReadResult llrr;
112 		long oldblock;
113 		int markedbad;
114 		DataBlock *db;
115 
116 		db = server->datablock + index;
117 		oldblock = db->block;
118 		errmsg = logfsservercopyactivedata(server, newb, index, 1, &llrr, &markedbad);
119 		if(errmsg) {
120 			if(!markedbad)
121 				return errmsg;
122 			newb = logfsfindfreeblock(ll, AllocReasonReplace);
123 			continue;
124 		}
125 		(*ll->markblockbad)(ll, oldblock);
126 		return nil;
127 	}
128 	return logfsefullreplacing;
129 }
130 
131 char *
132 logfsserverreplacelogblock(LogfsServer *server, LogSegment *seg, long index)
133 {
134 	ulong opath;
135 	LogfsLowLevel *ll = server->ll;
136 	long oldb = seg->blockmap[index];
137 
138 	opath = (*ll->getblockpath)(ll, oldb);
139 
140 	for(;;) {
141 		long newb;
142 		int pages;
143 		char *errmsg;
144 		LogfsLowLevelReadResult llrr;
145 		int markedbad;
146 
147 		newb  = logfsfindfreeblock(ll, AllocReasonReplace);
148 		if(newb < 0)
149 			return "full replacing log block";
150 		/* TODO - scavenge data space for a spare block */
151 		(*ll->setblocktag)(ll, newb, LogfsTlog);
152 		(*ll->setblockpath)(ll, newb, mklogpath(seg->gen, index, copygensucc(copygenof(opath))));
153 		if(index == seg->curblockindex)
154 			pages = seg->curpage;
155 		else
156 			pages = 1 << server->ll->l2pagesperblock;
157 		errmsg = copypages(server, newb, oldb, logfsdatapagemask(pages, 0), &llrr, &markedbad);
158 		if(errmsg == nil) {
159 			(*ll->markblockbad)(ll, seg->blockmap[index]);
160 			seg->blockmap[index] = newb;
161 			return nil;
162 		}
163 		if(!markedbad)
164 			return errmsg;
165 	}
166 }
167 
168 char *
169 logfsserverreplaceblock(LogfsServer *server, LogSegment *seg, long index)
170 {
171 	if(seg)
172 		return logfsserverreplacelogblock(server, seg, index);
173 	else
174 		return logfsserverreplacedatablock(server, index);
175 }
176