ref: e3aee39a389700ad821a1619f114e226c1bd42d0
dir: /sys/src/cmd/aux/flashfs/journal.c/
#include <u.h> #include <libc.h> #include <auth.h> #include <fcall.h> #include <thread.h> #include <9p.h> #include "flashfs.h" enum { debug = 0, diags = 1, }; typedef struct Gen Gen; typedef struct Sect Sect; struct Gen { int gnum; int count; int low; int high; Sect* head; Sect* tail; Sect* dup; Sect** vect; }; struct Sect { int sect; ulong seq; int coff; int toff; int sum; ulong time; Sect* next; }; static Gen gens[2]; static Sect* freehead; static Sect* freetail; static int nfree; static int nbad; static ulong ltime; static int cursect; /* * If we have a delta then file times are in the future. * But they drift back to reality. */ ulong now(void) { ulong cur, drift; static ulong last; cur = time(0); if(cur < last) delta += last - cur; else if(delta != 0 && last != 0) { drift = (cur - last + 1) / 2; if(drift > delta) delta = 0; else delta -= drift; } last = cur; return cur + delta; } static void damaged(char *mesg) { sysfatal("damaged filesystem: %s", mesg); } static void lddisc(char *mesg) { if(debug) fprint(2, "discard %s\n", mesg); else USED(mesg); } static Sect * getsect(void) { Sect *t; t = freehead; freehead = t->next; if(freehead == nil) freetail = nil; nfree--; return t; } static void newsect(Gen *g, Sect *s) { int m, n, err; uchar hdr[2*3]; if(debug) fprint(2, "new %d %ld\n", g->gnum, s->seq); if(g->tail == nil) g->head = s; else g->tail->next = s; g->tail = s; s->next = nil; m = putc3(&hdr[0], g->gnum); n = putc3(&hdr[m], s->seq); s->toff = MAGSIZE + m + n; s->coff = s->toff + 4; s->time = NOTIME; s->sum = 0; err = 1; for(;;) { if(writedata(err, s->sect, hdr, m + n, MAGSIZE) && writedata(err, s->sect, magic, MAGSIZE, 0)) break; clearsect(s->sect); err = 0; } } static Sect * newsum(Gen *g, ulong seq) { Sect *t; if(nfree == 0) damaged("no free sector for summary"); t = getsect(); t->seq = seq; newsect(g, t); return t; } static void freesect(Sect *s) { clearsect(s->sect); if(freetail == nil) freehead = s; else freetail->next = s; freetail = s; s->next = nil; nfree++; } static void dupsect(Sect *s, int renum) { Sect *t; Renum r; uchar *b; int err, n; ulong doff, off; if(nfree == 0) damaged("no free for copy"); t = getsect(); b = sectbuff; off = s->coff; readdata(s->sect, b, off, 0); doff = s->toff; if(s->time == NOTIME) doff += 4; // Window 5 err = 1; for(;;) { if(writedata(err, t->sect, b + 1, s->toff - 1, 1) && writedata(err, t->sect, b + doff, off - doff, doff) && writedata(err, t->sect, b, 1, 0)) break; clearsect(t->sect); err = 0; } if(renum) { r.old = s->sect; r.new = t->sect; erenum(&r); } n = s->sect; s->sect = t->sect; t->sect = n; freesect(t); if(cursect >= 0) readdata(cursect, b, sectsize, 0); } static void gswap(void) { Gen t; t = gens[0]; gens[0] = gens[1]; gens[1] = t; } static void checkdata(void) { Gen *g; g = &gens[0]; if(g->dup != nil) { // Window 5 damage if(diags) fprint(2, "%s: window 5 damage\n", argv0); freesect(g->dup); g->dup = nil; } } static void checksweep(void) { Gen *g; Jrec j; uchar *b; int n, op; Sect *s, *t, *u; long off, seq, soff; g = &gens[1]; if(g->dup != nil) { // Window 5 damage if(diags) fprint(2, "%s: window 5 damage\n", argv0); freesect(g->dup); g->dup = nil; } s = g->head; if(s != g->tail) { while(s->next != g->tail) s = s->next; } b = sectbuff; op = -1; seq = -1; soff = 0; u = nil; t = s; for(;;) { readdata(t->sect, b, sectsize, 0); off = t->toff + 4; for(;;) { n = convM2J(&j, &b[off]); if(n < 0) { if(j.type != 0xFF) { if(debug) fprint(2, "s[%d] @ %d %ld\n", j.type, t->sect, off); damaged("bad Jrec"); } break; } switch(j.type) { case FT_SUMMARY: case FT_SUMBEG: seq = j.seq; case FT_SUMEND: op = j.type; soff = off; u = t; break; case FT_WRITE: case FT_AWRITE: off += j.size; } off += n; } t = t->next; if(t == nil) break; } if(op == FT_SUMBEG) { // Window 1 damage if(diags) fprint(2, "%s: window 1 damage\n", argv0); if(u != s) { freesect(u); s->next = nil; g->tail = s; } s->coff = soff; dupsect(s, 0); seq--; } if(seq >= 0) { g = &gens[0]; if(seq > g->low) damaged("high sweep"); if(seq == g->low) { // Window 2 damage if(diags) fprint(2, "%s: window 2 damage\n", argv0); s = g->head; g->head = s->next; freesect(s); if(g->head == nil) { g->tail = nil; g->gnum += 2; newsum(g, 0); gswap(); } } } } void load1(Sect *s, int parity) { int n; Jrec j; uchar *b; char *err; Extent *x; Entry *d, *e; ulong ctime, off, mtime; if(s->sect < 0 && readonly) // readonly damaged return; b = sectbuff; readdata(s->sect, b, sectsize, 0); s->sum = 0; off = s->toff; ctime = get4(&b[off]); off += 4; for(;;) { n = convM2J(&j, &b[off]); if(n < 0) { if(j.type != 0xFF) { if(debug) fprint(2, "l[%d] @ %d %ld\n", j.type, s->sect, off); damaged("bad Jrec"); } s->coff = off; break; } off += n; if(debug) fprint(2, "get %J\n", &j); switch(j.type) { case FT_create: ctime += j.mtime; create: d = elookup(j.parent); if(d == nil) { lddisc("parent"); break; } d->ref++; e = ecreate(d, j.name, j.fnum, j.mode, ctime, &err); if(e == nil) { d->ref--; lddisc("create"); break; } e->ref--; if(j.type == FT_trunc) e->mode = j.mode; break; case FT_chmod: e = elookup(j.fnum); if(e == nil) { lddisc("lookup"); break; } echmod(e, j.mode, j.mnum); break; case FT_REMOVE: e = elookup(j.fnum); if(e == nil) { lddisc("lookup"); break; } if(eremove(e) != nil) { lddisc("remove"); break; } break; case FT_AWRITE: mtime = 0; goto write; case FT_WRITE: ctime += j.mtime; mtime = ctime; write: x = emalloc9p(sizeof(Extent)); x->sect = s->sect; x->addr = off; x->off = j.offset; x->size = j.size; off += j.size; e = elookup(j.fnum); if(e == nil) { lddisc("lookup"); break; } ewrite(e, x, parity, mtime); break; case FT_trunc: ctime += j.mtime; e = elookup(j.tnum); if(e == nil) { if(debug) fprint(2, "-> create\n"); goto create; } etrunc(e, j.fnum, ctime); break; case FT_SUMMARY: case FT_SUMBEG: case FT_SUMEND: s->sum += n; break; default: damaged("load1 botch"); } } if(s->sum > Nsum) s->sum = Nsum; s->time = ctime; if(ctime != NOTIME && ctime > ltime) ltime = ctime; } void load0(int parity) { Sect *s; if(debug) fprint(2, "load %d\n", parity); for(s = gens[parity].head; s != nil; s = s->next) load1(s, parity); } void loadfs(int ro) { Gen *g; Sect *s; ulong u, v; int i, j, n; uchar hdr[MAXHDR]; readonly = ro; fmtinstall('J', Jconv); for(i = 0; i < 2; i++) { g = &gens[i]; g->gnum = -1; g->low = nsects; g->high = -1; g->count = 0; g->head = nil; g->tail = nil; } for(i = 0; i < nsects; i++) { readdata(i, hdr, MAXHDR, 0); if(memcmp(hdr, magic, MAGSIZE) == 0) { n = MAGSIZE + getc3(&hdr[MAGSIZE], &u); getc3(&hdr[n], &v); if(debug) fprint(2, "%d: %ld %ld\n", i, u, v); for(j = 0; j < 2; j++) { g = &gens[j]; if(g->gnum == u) { g->count++; if(v < g->low) g->low = v; if(v > g->high) g->high = v; break; } else if(g->gnum < 0) { g->gnum = u; g->count = 1; g->low = v; g->high = v; break; } } if(j == 2) damaged("unexpected generation"); } else if(hdr[0] == 0xFF) { nfree++; s = emalloc9p(sizeof(Sect)); s->sect = i; s->next = freehead; freehead = s; if(freetail == nil) freetail = s; } else nbad++; } if(nbad > 0) damaged("bad sectors"); if(gens[0].gnum < 0) damaged("no data"); if(gens[1].gnum < 0) { // Window 3 death if(diags) fprint(2, "%s: window 3 damage\n", argv0); g = &gens[1]; g->gnum = gens[0].gnum + 1; g->low = 0; g->high = 0; g->count = 1; if(!readonly) newsum(g, 0); } if(gens[0].gnum > gens[1].gnum) gswap(); for(i = 0; i < 2; i++) { g = &gens[i]; n = g->count; if(n <= g->high - g->low) damaged("missing sectors"); g->vect = emalloc9p(n * sizeof(Sect *)); for(j = 0; j < n; j++) { s = emalloc9p(sizeof(Sect)); s->sect = -1; g->vect[j] = s; } } if(debug) { for(j = 0; j < 2; j++) { g = &gens[j]; print("%d\t%d\t%d-%d\n", g->gnum, g->count, g->low, g->high); } } for(i = 0; i < nsects; i++) { readdata(i, hdr, MAXHDR, 0); if(memcmp(hdr, magic, MAGSIZE) == 0) { n = MAGSIZE + getc3(&hdr[MAGSIZE], &u); n += getc3(&hdr[n], &v); g = nil; for(j = 0; j < 2; j++) { g = &gens[j]; if(g->gnum == u) break; } if(j == 2) damaged("generation botch"); s = g->vect[v - g->low]; s->seq = v; s->toff = n; if(s->sect < 0) s->sect = i; else if(v == g->high && g->dup == nil) { s = emalloc9p(sizeof(Sect)); s->sect = i; g->dup = s; } else damaged("dup block"); } } for(j = 0; j < 2; j++) { g = &gens[j]; for(i = 0; i < g->count; i++) { s = g->vect[i]; if(g->tail == nil) g->head = s; else g->tail->next = s; g->tail = s; s->next = nil; } free(g->vect); } cursect = -1; if(!readonly) { checkdata(); checksweep(); } load0(1); load0(0); if(ltime != 0) { u = now(); if(u < ltime) { delta = ltime - u; if(diags) fprint(2, "%s: check clock: delta = %lud\n", argv0, delta); } } limit = 80 * nsects * sectsize / 100; maxwrite = sectsize - MAXHDR - Nwrite - Nsum; if(maxwrite > WRSIZE) maxwrite = WRSIZE; } static int sputw(Sect *s, Jrec *j, int mtime, Extent *x, void *a) { ulong t; int err, n, r; uchar buff[Nmax], type[1]; if(debug) fprint(2, "put %J\n", j); if(mtime) { t = j->mtime; if(s->time == NOTIME) { put4(buff, t); if(!writedata(1, s->sect, buff, 4, s->toff)) { dupsect(s, 1); writedata(0, s->sect, buff, 4, s->toff); } s->time = t; j->mtime = 0; } else { j->mtime = t - s->time; s->time = t; } } n = convJ2M(j, buff); if(n < 0) damaged("convJ2M"); // Window 4 err = 2; for(;;) { err--; if(!err) dupsect(s, 1); // Window 4 damage t = s->coff + 1; if(!writedata(err, s->sect, buff, n, t)) continue; t += n; r = n; if(x != nil) { x->sect = s->sect; x->addr = t; if(!writedata(err, s->sect, a, j->size, t)) continue; t += j->size; r += j->size; } type[0] = j->type; if(!writedata(err, s->sect, type, 1, s->coff)) continue; r++; break; } s->coff = t; return r; } static void summarize(void) { Gen *g; uchar *b; Entry *e; Extent *x; Jrec j, sum; Sect *s, *t; ulong off, ctime; int n, bytes, more, mtime, sumd; g = &gens[eparity]; s = g->head; g->head = s->next; if(g->head == nil) g->tail = nil; g = &gens[eparity^1]; t = g->tail; b = sectbuff; x = nil; if(debug) fprint(2, "summarize\n"); for(;;) { // Window 1 readdata(s->sect, b, sectsize, 0); off = s->toff; ctime = get4(&b[off]); off += 4; sumd = 0; cursect = s->sect; while(b[off] != 0xFF) { n = convM2J(&j, &b[off]); if(n < 0) damaged("bad Jrec"); if(debug) fprint(2, "read %J\n", &j); off += n; bytes = n; mtime = 0; switch(j.type) { case FT_create: ctime += j.mtime; mtime = 1; create: e = elookup(j.fnum); if(e == nil) continue; break; case FT_chmod: e = elookup(j.fnum); if(e == nil || j.mnum != e->mnum) continue; break; case FT_REMOVE: e = elookup(j.fnum); if(e == nil) continue; break; case FT_trunc: ctime += j.mtime; mtime = 1; e = elookup(j.tnum); if(e == nil) { if(debug) fprint(2, "-> create\n"); j.type = FT_create; goto create; } break; case FT_AWRITE: goto write; case FT_WRITE: ctime += j.mtime; mtime = 1; write: e = elookup(j.fnum); if(e == nil) { off += j.size; continue; } x = esum(e, s->sect, off, &more); if(x == nil) { damaged("missing extent"); off += j.size; continue; } if(more) { j.type = FT_AWRITE; mtime = 0; } bytes += j.size; break; case FT_SUMMARY: case FT_SUMBEG: case FT_SUMEND: continue; default: damaged("summarize botch"); } if(!sumd) { if(t->coff + Nsumbeg >= sectsize - 1) t = newsum(g, t->seq + 1); sum.type = FT_SUMBEG; sum.seq = s->seq; if(debug) fprint(2, "+ %J\n", &sum); t->sum += sputw(t, &sum, 0, nil, nil); if(t->sum >= Nsum) t->sum = Nsum; sumd = 1; } if(t->coff + bytes >= sectsize - Nsum + t->sum - 1) t = newsum(g, t->seq + 1); if(mtime) j.mtime = ctime; switch(j.type) { case FT_AWRITE: case FT_WRITE: sputw(t, &j, mtime, x, &b[off]); off += j.size; break; default: sputw(t, &j, mtime, nil, nil); } } cursect = -1; if(t->coff + Nsumbeg >= sectsize - 1) t = newsum(g, t->seq + 1); if(sumd) sum.type = FT_SUMEND; else { sum.type = FT_SUMMARY; sum.seq = s->seq; } if(debug) fprint(2, "+ %J\n", &sum); t->sum += sputw(t, &sum, 0, nil, nil); if(t->sum >= Nsum) t->sum = Nsum; // Window 2 freesect(s); g = &gens[eparity]; s = g->head; if(s == nil) { // Window 3 g->gnum += 2; newsum(g, 0); eparity ^= 1; return; } if(nfree >= Nfree) return; g->head = s->next; if(g->head == nil) g->tail = nil; g = &gens[eparity^1]; } } char * need(int bytes) { Gen *g; int sums; Sect *s, *t; sums = 0; for(;;) { s = gens[eparity].tail; if(s->coff + bytes < sectsize - Nsum + s->sum - 1) return nil; if(nfree >= Nfree) break; if(sums == 2) { readonly = 1; return "generation full"; } summarize(); sums++; } g = &gens[eparity]; t = getsect(); t->seq = g->tail->seq + 1; newsect(g, t); return nil; } void putw(Jrec *j, int mtime, Extent *x, void *a) { sputw(gens[eparity].tail, j, mtime, x, a); } void put(Jrec *j, int mtime) { sputw(gens[eparity].tail, j, mtime, nil, nil); }