ref: 9d215d5af232112242d17641304c037d16cd0290
dir: /blk.c/
#include <u.h>
#include <libc.h>
#include <fcall.h>
#include <avl.h>
#include "dat.h"
#include "fns.h"
typedef struct Range Range;
struct Range {
vlong off;
vlong len;
};
static vlong blkalloc_lk(Arena*);
static vlong blkalloc(int);
static int blkdealloc_lk(vlong);
static Blk* initblk(Blk*, vlong, int);
static int logop(Arena *, vlong, vlong, int);
int
checkflag(Blk *b, int f)
{
return (b->flag & f) == f;
}
void
setflag(Blk *b, int f)
{
long ov, nv;
while(1){
ov = b->flag;
nv = ov | f;
if(cas(&b->flag, ov, nv))
break;
}
}
void
clrflag(Blk *b, int f)
{
long ov, nv;
while(1){
ov = b->flag;
nv = ov & ~f;
if(cas(&b->flag, ov, nv))
break;
}
}
int
syncblk(Blk *b)
{
assert(checkflag(b, Bfinal));
clrflag(b, Bdirty);
return pwrite(fs->fd, b->buf, Blksz, b->bp.addr);
}
static Blk*
readblk(vlong bp, int flg)
{
Blk *b;
vlong off, rem, n;
assert(bp != -1);
if((b = cachepluck()) == nil)
return nil;
b->alloced = getcallerpc(&bp);
off = bp;
rem = Blksz;
while(rem != 0){
n = pread(fs->fd, b->buf, rem, off);
if(n <= 0){
dropblk(b);
return nil;
}
off += n;
rem -= n;
}
b->cnext = nil;
b->cprev = nil;
b->hnext = nil;
b->flag = 0;
b->type = (flg&GBraw) ? Traw : UNPACK16(b->buf+0);
b->bp.addr = bp;
b->bp.hash = -1;
b->bp.gen = -1;
b->fnext = nil;
b->nval = 0;
b->valsz = 0;
b->nbuf = 0;
b->bufsz = 0;
b->logsz = 0;
b->lognxt = 0;
switch(b->type){
default:
fprint(2, "invalid block @%llx\n", bp);
abort();
break;
case Traw:
case Tarena:
b->data = b->buf;
break;
case Tlog:
case Tdead:
b->data = b->buf + Loghdsz;
break;
break;
case Tpivot:
b->data = b->buf + Pivhdsz;
b->nval = UNPACK16(b->buf+2);
b->valsz = UNPACK16(b->buf+4);
b->nbuf = UNPACK16(b->buf+6);
b->bufsz = UNPACK16(b->buf+8);
break;
case Tleaf:
b->data = b->buf + Leafhdsz;
b->nval = UNPACK16(b->buf+2);
b->valsz = UNPACK16(b->buf+4);
break;
}
assert(b->magic == Magic);
return b;
}
static Arena*
pickarena(int hint, int tries)
{
int n;
n = hint*7;
n += tries;
n += ainc(&fs->roundrobin)/(1024*1024);
return &fs->arenas[n%fs->narena];
}
Arena*
getarena(vlong b)
{
int i;
i = b / fs->arenasz;
if(i < 0 || i >= fs->narena){
werrstr("out of range block %lld", b);
abort();
return nil;
}
return &fs->arenas[i];
}
static int
freerange(Avltree *t, vlong off, vlong len)
{
Arange *r, *s;
assert(len % Blksz == 0);
if((r = calloc(1, sizeof(Arange))) == nil)
return -1;
r->off = off;
r->len = len;
assert(avllookup(t, r, 0) == nil);
avlinsert(t, r);
Again:
s = (Arange*)avlprev(r);
if(s != nil && s->off+s->len == r->off){
avldelete(t, r);
s->len = s->len + r->len;
free(r);
r = s;
goto Again;
}
s = (Arange*)avlnext(r);
if(s != nil && r->off+r->len == s->off){
avldelete(t, r);
s->off = r->off;
s->len = s->len + r->len;
free(r);
r = s;
goto Again;
}
return 0;
}
static int
syncarena(Arena *a)
{
packarena(a->b->data, Blksz, a, fs);
finalize(a->b);
return syncblk(a->b);
}
static int
grabrange(Avltree *t, vlong off, vlong len)
{
Arange *r, *s, q;
vlong l;
assert(len % Blksz == 0);
q.off = off;
q.len = len;
r = (Arange*)avllookup(t, &q.Avl, -1);
if(r == nil || off + len > r->off + r->len)
abort();
if(off == r->off){
r->off += len;
r->len -= len;
}else if(off + len == r->off + r->len){
r->len -= len;
}else if(off > r->off && off+len < r->off + r->len){
if((s = malloc(sizeof(Arange))) == nil)
return -1;
l = r->len;
s->off = off + len;
r->len = off - r->off;
s->len = l - r->len - len;
avlinsert(t, s);
}else
abort();
if(r->len == 0){
avldelete(t, r);
free(r);
}
return 0;
}
/*
* Logs an allocation. Must be called
* with arena lock held. Duplicates some
* of the work in allocblk to prevent
* recursion.
*/
static int
logappend(Arena *a, vlong off, vlong len, int op, Blk **tl)
{
Blk *pb, *lb;
vlong o;
char *p;
assert(off % Blksz == 0);
assert(op == LogAlloc || op == LogFree);
o = -1;
lb = *tl;
dprint("logop %llx+%llx@%llx: %s\n", off, len, lb->logsz, (op == LogAlloc) ? "Alloc" : "Free");
/*
* move to the next block when we have
* 40 bytes in the log:
* We're appending up to 16 bytes as
* part of the operation, followed by
* 16 bytes of new log entry allocation
* and chaining.
*/
if(lb == nil || lb->logsz >= Logspc - 40){
pb = lb;
if((o = blkalloc_lk(a)) == -1)
return -1;
if((lb = cachepluck()) == nil)
return -1;
initblk(lb, o, Tlog);
cacheins(lb);
lb->logsz = Loghashsz;
p = lb->data + lb->logsz;
PACK64(p+0, o|LogAlloc1);
PACK64(p+8, (uvlong)LogEnd);
finalize(lb);
if(syncblk(lb) == -1){
dropblk(lb);
return -1;
}
if(pb != nil){
p = pb->data + pb->logsz;
PACK64(p, lb->bp.addr|LogChain);
finalize(pb);
if(syncblk(pb) == -1){
dropblk(pb);
return -1;
}
dropblk(pb);
}
*tl = lb;
}
if(len == Blksz){
if(op == LogAlloc)
op = LogAlloc1;
else if(op == LogFree)
op = LogFree1;
}
off |= op;
p = lb->data + lb->logsz;
PACK64(p, off);
lb->logsz += 8;
if(op >= Log2wide){
PACK64(p+8, len);
lb->logsz += 8;
}
/*
* The newly allocated log block needs
* to be recorded. If we're compressing
* a log, it needs to go to the tail of
* the new log, rather than after the
* current allocation.
*
* Because we've just grown the log, we
* know it won't recurse.
*/
if(o != -1)
logop(a, o, Blksz, LogAlloc);
/* this gets overwritten by the next append */
p = lb->data + lb->logsz;
PACK64(p, (uvlong)LogEnd);
return 0;
}
static int
logop(Arena *a, vlong off, vlong len, int op)
{
if(logappend(a, off, len, op, &a->tail) == -1)
return -1;
if(a->head.addr == -1)
a->head = a->tail->bp;
return 0;
}
int
loadlog(Arena *a)
{
vlong ent, off, len;
int op, i, n;
uvlong bh;
Bptr bp;
char *d;
Blk *b;
bp = a->head;
Nextblk:
if((b = getblk(bp, GBnochk)) == nil)
return -1;
bh = UNPACK64(b->data);
/* the hash covers the log and offset */
if(bh != siphash(b->data+Loghashsz, Logspc-Loghashsz)){
werrstr("corrupt log");
return -1;
}
for(i = Loghashsz; i < Logspc; i += n){
d = b->data + i;
ent = UNPACK64(d);
op = ent & 0xff;
off = ent & ~0xff;
n = (op >= Log2wide) ? 16 : 8;
switch(op){
case LogEnd:
dprint("log@%d: end\n", i);
dropblk(b);
return 0;
case LogChain:
bp.addr = off & ~0xff;
bp.hash = -1;
bp.gen = -1;
dropblk(b);
dprint("log@%d: chain %B\n", i, bp);
goto Nextblk;
break;
case LogAlloc:
case LogAlloc1:
len = (op >= Log2wide) ? UNPACK64(d+8) : Blksz;
dprint("log@%d alloc: %llx+%llx\n", i, off, len);
if(grabrange(a->free, off & ~0xff, len) == -1)
return -1;
break;
case LogFree:
case LogFree1:
len = (op >= Log2wide) ? UNPACK64(d+8) : Blksz;
dprint("log@%d free: %llx+%llx\n", i, off, len);
if(freerange(a->free, off & ~0xff, len) == -1)
return -1;
break;
default:
n = 0;
dprint("log@%d: log op %d\n", i, op);
abort();
break;
}
}
return -1;
}
int
compresslog(Arena *a)
{
Arange *r;
Range *log, *nlog;
vlong v, ba, na, graft, oldhd;
int i, n, sz;
Blk *b, *hd, *tl;
Bptr bp;
char *p;
/*
* Sync the current log to disk, and
* set up a new block log tail. While
* compressing the log, nothing else is
* using this arena, so any allocs come
* from the log compression, and go into
* this new log segment.
*
* A bit of copy paste from newblk,
* because otherwise we have a deadlock
* allocating the block.
*/
if((ba = blkalloc_lk(a)) == -1)
return -1;
if((b = cachepluck()) == nil)
return -1;
initblk(b, ba, Tlog);
b->logsz = Loghashsz;
p = b->data + b->logsz;
PACK64(p, (uvlong)LogEnd);
finalize(b);
if(syncblk(b) == -1){
dropblk(b);
return -1;
}
graft = b->bp.addr;
if(a->tail != nil){
finalize(a->tail);
if(syncblk(a->tail) == -1){
dropblk(b);
return -1;
}
}
a->tail = b;
/*
* Prepare what we're writing back.
* Arenas must be sized so that we can
* keep the merged log in memory for
* a rewrite.
*/
n = 0;
sz = 512;
if((log = malloc(sz*sizeof(Range))) == nil)
return -1;
/*
* we need to allocate this block before
* we prepare the ranges we write back,
* so we don't record this block as
* available when we compress the log.
*/
if((ba = blkalloc_lk(a)) == -1){
free(log);
return -1;
}
initblk(b, ba, Tlog);
for(r = (Arange*)avlmin(a->free); r != nil; r = (Arange*)avlnext(r)){
if(n == sz){
sz *= 2;
if((nlog = realloc(log, sz*sizeof(Range))) == nil){
free(log);
return -1;
}
log = nlog;
}
log[n].off = r->off;
log[n].len = r->len;
n++;
}
hd = b;
tl = b;
b->logsz = Loghashsz;
for(i = 0; i < n; i++)
if(logappend(a, log[i].off, log[i].len, LogFree, &tl) == -1)
return -1;
p = tl->data + tl->logsz;
PACK64(p, LogChain|graft);
free(log);
finalize(tl);
if(syncblk(tl) == -1)
return -1;
oldhd = a->head.addr;
a->head.addr = hd->bp.addr;
a->head.hash = hd->bp.hash;
a->head.gen = -1;
if(syncarena(a) == -1)
return -1;
if(oldhd != -1){
for(ba = oldhd; ba != -1; ba = na){
na = -1;
bp.addr = ba;
bp.hash = -1;
bp.gen = -1;
if((b = getblk(bp, GBnochk)) == nil)
return -1;
for(i = Loghashsz; i < Logspc; i += n){
p = b->data + i;
v = UNPACK64(p);
n = ((v&0xff) >= Log2wide) ? 16 : 8;
if((v&0xff) == LogChain){
na = v & ~0xff;
break;
}else if((v&0xff) == LogEnd){
na = -1;
break;
}
}
lock(a);
cachedel(b->bp.addr);
if(blkdealloc_lk(ba) == -1){
unlock(a);
return -1;
}
dropblk(b);
unlock(a);
}
}
finalize(a->tail);
if(syncblk(a->tail) == -1)
return -1;
return 0;
}
/*
* Allocate from an arena, with lock
* held. May be called multiple times
* per operation, to alloc space for
* the alloc log.
*/
static vlong
blkalloc_lk(Arena *a)
{
Avltree *t;
Arange *r;
vlong b;
t = a->free;
r = (Arange*)t->root;
if(r == nil)
return -1;
/*
* A bit of sleight of hand here:
* while we're changing the sorting
* key, but we know it won't change
* the sort order because the tree
* covers disjoint ranges
*/
b = r->off;
r->len -= Blksz;
r->off += Blksz;
if(r->len == 0){
avldelete(t, r);
free(r);
}
a->used += Blksz;
return b;
}
static int
blkdealloc_lk(vlong b)
{
Arena *a;
int r;
r = -1;
a = getarena(b);
if(freerange(a->free, b, Blksz) == -1)
goto out;
if(logop(a, b, Blksz, LogFree) == -1)
goto out;
a->used -= Blksz;
r = 0;
out:
return r;
}
static vlong
blkalloc(int hint)
{
Arena *a;
vlong b;
int tries;
tries = 0;
Again:
a = pickarena(hint, tries);
if(a == nil || tries == fs->narena){
werrstr("no empty arenas");
return -1;
}
/*
* TODO: there's an extreme edge case
* here.
*
* If the file system has room to alloc
* a data block but no log block, then
* we end up with it in a stuck state.
* The fix is to reserve alloc blocks,
* so that we're guaranteed to be able
* to log an alloc if the disk is working
* correctly.
*/
tries++;
lock(a);
if((b = blkalloc_lk(a)) == -1){
unlock(a);
goto Again;
}
if(logop(a, b, Blksz, LogAlloc) == -1){
unlock(a);
return -1;
}
unlock(a);
return b;
}
static Blk*
initblk(Blk *b, vlong bp, int t)
{
Blk *ob;
ob = cacheget(bp);
if(ob != nil){
fprint(2, "dup block: %#p %B (alloced %#llx freed %#llx lasthold: %#llx, lastdrop: %#llx)\n",
ob, ob->bp, ob->alloced, ob->freed, ob->lasthold, ob->lastdrop);
abort();
}
b->type = t;
b->bp.addr = bp;
b->bp.hash = -1;
b->bp.gen = fs->nextgen;
lock(&fs->freelk);
b->qgen = fs->qgen;
unlock(&fs->freelk);
switch(t){
case Traw:
case Tarena:
b->data = b->buf;
break;
case Tdead:
case Tlog:
b->data = b->buf + Loghdsz;
break;
case Tpivot:
b->data = b->buf + Pivhdsz;
break;
case Tleaf:
b->data = b->buf + Leafhdsz;
break;
}
b->fnext = nil;
setflag(b, Bdirty);
b->nval = 0;
b->valsz = 0;
b->nbuf = 0;
b->bufsz = 0;
b->logsz = 0;
b->lognxt = 0;
b->alloced = getcallerpc(&b);
return b;
}
Blk*
newblk(int t)
{
vlong bp;
Blk *b;
if((bp = blkalloc(t)) == -1)
return nil;
if((b = cachepluck()) == nil)
return nil;
initblk(b, bp, t);
b->alloced = getcallerpc(&t);
return b;
}
Blk*
dupblk(Blk *b)
{
Blk *r;
if((r = newblk(b->type)) == nil)
return nil;
setflag(r, Bdirty);
r->bp.hash = b->bp.hash;
r->nval = b->nval;
r->valsz = b->valsz;
r->nbuf = b->nbuf;
r->bufsz = b->bufsz;
r->logsz = b->logsz;
r->lognxt = b->lognxt;
r->alloced = getcallerpc(&b);
memcpy(r->buf, b->buf, sizeof(r->buf));
return r;
}
void
finalize(Blk *b)
{
uvlong h;
if(b->type != Traw)
PACK16(b->buf, b->type);
lock(&fs->freelk);
b->qgen = fs->qgen;
unlock(&fs->freelk);
switch(b->type){
default:
case Tpivot:
PACK16(b->buf+2, b->nval);
PACK16(b->buf+4, b->valsz);
PACK16(b->buf+6, b->nbuf);
PACK16(b->buf+8, b->bufsz);
b->bp.hash = blkhash(b);
break;
case Tleaf:
PACK16(b->buf+2, b->nval);
PACK16(b->buf+4, b->valsz);
b->bp.hash = blkhash(b);
break;
case Tlog:
case Tdead:
h = siphash(b->data + Loghashsz, Logspc-Loghashsz);
PACK64(b->data, h);
b->bp.hash = blkhash(b);
break;
case Traw:
b->bp.hash = blkhash(b);
break;
case Tmagic:
case Tarena:
break;
}
setflag(b, Bfinal);
cacheins(b);
}
Blk*
getblk(Bptr bp, int flg)
{
uvlong h;
Blk *b;
int i;
i = ihash(bp.addr) % nelem(fs->blklk);
qlock(&fs->blklk[i]);
if((b = cacheget(bp.addr)) != nil){
qunlock(&fs->blklk[i]);
return b;
}
dprint("read %B from %#llx\n", bp, getcallerpc(&bp));
if((b = readblk(bp.addr, flg)) == nil){
qunlock(&fs->blklk[i]);
return nil;
}
b->alloced = getcallerpc(&bp);
h = blkhash(b);
if((flg&GBnochk) == 0 && h != bp.hash){
fprint(2, "corrupt block %p %B: %.16llux != %.16llux\n", b, bp, h, bp.hash);
qunlock(&fs->blklk[i]);
abort();
return nil;
}
b->bp.hash = h;
b->bp.gen = bp.gen;
cacheins(b);
qunlock(&fs->blklk[i]);
return b;
}
Blk*
holdblk(Blk *b)
{
ainc(&b->ref);
b->lasthold = getcallerpc(&b);
return b;
}
void
dropblk(Blk *b)
{
assert(b == nil || b->ref > 0);
if(b == nil || adec(&b->ref) != 0)
return;
b->lastdrop = getcallerpc(&b);
/*
* While a freed block can get resurrected
* before quiescence, it's unlikely -- so
* it goes into the bottom of the LRU to
* get selected early for reuse.
*/
if(checkflag(b, Bfreed))
lrubot(b);
else
lrutop(b);
}
ushort
blkfill(Blk *b)
{
switch(b->type){
case Tpivot:
return 2*b->nbuf + b->bufsz + 2*b->nval + b->valsz;
case Tleaf:
return 2*b->nval + b->valsz;
default:
fprint(2, "invalid block @%lld\n", b->bp.addr);
abort();
}
return 0; // shut up kencc
}
void
freebp(Tree *t, Bptr bp)
{
Bfree *f;
if(t != nil && t != &fs->snap && bp.gen <= t->gen){
killblk(t, bp);
return;
}
if((f = malloc(sizeof(Bfree))) == nil)
return;
f->bp = bp;
lock(&fs->freelk);
f->next = fs->freehd;
fs->freehd = f;
unlock(&fs->freelk);
}
void
freeblk(Tree *t, Blk *b)
{
b->freed = getcallerpc(&t);
setflag(b, Bfreed);
freebp(t, b->bp);
}
void
epochstart(int tid)
{
ainc((long*)&fs->active[tid]);
}
void
epochend(int tid)
{
ainc((long*)&fs->active[tid]);
}
void
epochclean(void)
{
int i, allquiesced;
Bfree *p, *n;
Arena *a;
lock(&fs->activelk);
allquiesced = 1;
for(i = 0; i < fs->nquiesce; i++){
/*
* Odd parity on quiescence implies
* that we're between the exit from
* and waiting for the next message
* that enters us into the critical
* section.
*/
if((fs->active[i] & 1) != 0)
continue;
if(fs->active[i] == fs->lastactive[i])
allquiesced = 0;
}
p = nil;
if(allquiesced){
for(i = 0; i < fs->nquiesce; i++)
fs->lastactive[i] = fs->active[i];
lock(&fs->freelk);
fs->qgen++;
if(fs->freep != nil){
p = fs->freep->next;
fs->freep->next = nil;
}
fs->freep = fs->freehd;
unlock(&fs->freelk);
}
unlock(&fs->activelk);
while(p != nil){
n = p->next;
a = getarena(p->bp.addr);
lock(a);
cachedel(p->bp.addr);
blkdealloc_lk(p->bp.addr);
unlock(a);
free(p);
p = n;
}
}
int
blkcmp(Blk *a, Blk *b)
{
if(a->qgen != b->qgen)
return (a->qgen < b->qgen) ? -1 : 1;
if(a->bp.addr != b->bp.addr)
return (a->bp.addr < b->bp.addr) ? -1 : 1;
return 0;
}
void
enqueue(Blk *b)
{
Arena *a;
a = getarena(b->bp.addr);
assert(checkflag(b, Bdirty));
holdblk(b);
finalize(b);
qput(a->sync, b);
}
void
qinit(Syncq *q)
{
q->fullrz.l = &q->lk;
q->emptyrz.l = &q->lk;
q->nheap = 0;
q->heapsz = fs->cmax;
if((q->heap = malloc(q->heapsz*sizeof(Blk*))) == nil)
sysfatal("alloc queue: %r");
}
void
qput(Syncq *q, Blk *b)
{
int i;
qlock(&q->lk);
while(q->nheap == q->heapsz)
rsleep(&q->fullrz);
for(i = q->nheap; i > 0; i = (i-1)/2){
if(blkcmp(b, q->heap[(i-1)/2]) == 1)
break;
q->heap[i] = q->heap[(i-1)/2];
}
q->heap[i] = b;
q->nheap++;
rwakeup(&q->emptyrz);
qunlock(&q->lk);
}
static Blk*
qpop(Syncq *q)
{
int i, l, r, m;
Blk *b, *t;
qlock(&q->lk);
while(q->nheap == 0)
rsleep(&q->emptyrz);
b = q->heap[0];
if(--q->nheap == 0)
goto Out;
i = 0;
q->heap[0] = q->heap[q->nheap];
while(1){
m = i;
l = 2*i+1;
r = 2*i+2;
if(l < q->nheap && blkcmp(q->heap[m], q->heap[l]) == 1)
m = l;
if(r < q->nheap && blkcmp(q->heap[m], q->heap[r]) == 1)
m = r;
if(m == i)
break;
t = q->heap[m];
q->heap[m] = q->heap[i];
q->heap[i] = t;
i = m;
}
Out:
rwakeup(&q->fullrz);
qunlock(&q->lk);
return b;
}
void
runsync(int, void *p)
{
Syncq *q;
Blk *b;
q = p;
while(1){
b = qpop(q);
if(b->type == Tmagic){
qlock(&fs->synclk);
if(--fs->syncing == 0)
rwakeupall(&fs->syncrz);
qunlock(&fs->synclk);
continue;
}
if(!checkflag(b, Bfreed)){
if(syncblk(b) == -1){
ainc(&fs->broken);
fprint(2, "write: %r");
abort();
}
}
dropblk(b);
}
}
void
sync(void)
{
Arena *a;
Blk *b;
int i;
qlock(&fs->synclk);
fs->syncing = fs->nsyncers;
for(i = 0; i < fs->nsyncers; i++){
b = cachepluck();
b->type = Tmagic;
qput(&fs->syncq[0], b);
}
while(fs->syncing != 0)
rsleep(&fs->syncrz);
for(i = 0; i < fs->narena; i++){
a = &fs->arenas[i];
finalize(a->tail);
if(syncblk(a->tail) == -1)
sysfatal("sync arena: %r");
if(syncarena(a) == -1)
sysfatal("sync arena: %r");
}
qunlock(&fs->synclk);
}