ref: 9244c8930f982302093f84016987a91fa7f007b3
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(void);
static int blkdealloc_lk(vlong);
static void cachedel(vlong);
QLock blklock;
Blk*
readblk(vlong bp, int flg)
{
Blk *b;
vlong off, rem, n;
assert(bp != -1);
if((b = mallocz(sizeof(Blk), 1)) == nil)
return nil;
off = bp;
rem = Blksz;
while(rem != 0){
n = pread(fs->fd, b->buf, rem, off);
if(n <= 0){
free(b);
return nil;
}
off += n;
rem -= n;
}
memset(&b->Lock, 0, sizeof(Lock));
b->type = (flg&GBraw) ? Traw : GBIT16(b->buf+0);
b->bp.addr = bp;
b->bp.hash = -1;
b->bp.gen = -1;
b->ref = 1;
b->cnext = nil;
b->cprev = nil;
b->hnext = nil;
b->data = b->buf + 10;
switch(b->type){
default:
if(flg&GBraw)
break;
fprint(2, "invalid block @%llx\n", bp);
abort();
break;
case Tarena:
case Traw:
case Tsuper:
case Tlog:
break;
case Tpivot:
b->nval = GBIT16(b->buf+2);
b->valsz = GBIT16(b->buf+4);
b->nbuf = GBIT16(b->buf+6);
b->bufsz = GBIT16(b->buf+8);
break;
case Tleaf:
b->nval = GBIT16(b->buf+2);
b->valsz = GBIT16(b->buf+4);
break;
}
return b;
}
static Arena*
pickarena(void)
{
long n;
n = (ainc(&fs->roundrobin)/1024) % fs->narena;
return &fs->arenas[n];
}
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;
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;
}
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;
}
Blk*
logappend(Oplog *ol, Arena *a, vlong off, vlong len, int op)
{
Blk *pb, *lb;
vlong o;
char *p;
assert(off % Blksz == 0);
assert(op == LogAlloc || op == LogFree);
lb = ol->tail;
if(lb == nil || lb->logsz > Logspc - 8){
pb = lb;
if(a == nil)
o = blkalloc();
else
o = blkalloc_lk(a);
if(o == -1)
return nil;
if((lb = mallocz(sizeof(Blk), 1)) == nil)
return nil;
lb->data = lb->buf + Hdrsz;
lb->flag |= Bdirty;
lb->type = Tlog;
lb->bp.addr = o;
lb->logsz = Loghdsz;
p = lb->data + lb->logsz;
PBIT64(p + 0, (uvlong)LogEnd);
finalize(lb);
if(syncblk(lb) == -1){
free(lb);
return nil;
}
ol->tail = lb;
if(pb != nil){
p = pb->data + pb->logsz;
PBIT64(p + 0, lb->bp.addr|LogChain);
finalize(pb);
if(syncblk(pb) == -1)
return nil;
}
}
p = lb->data + lb->logsz;
if(len == Blksz){
off |= (op & ~Log2w);
PBIT64(p, off);
lb->logsz += 8;
}else{
off |= op;
PBIT64(p+0, off);
PBIT64(p+8, len);
lb->logsz += 16;
}
/* this gets overwritten by the next append */
p = lb->data + lb->logsz;
PBIT64(p, (uvlong)LogEnd);
return lb;
}
/*
* Logs an allocation. Must be called
* with arena lock held. Duplicates some/c
* of the work in allocblk to prevent
* recursion.
*/
int
logop(Arena *a, vlong off, int op)
{
Blk *b;
if((b = logappend(&a->log, a, off, Blksz, op)) == nil)
return -1;
if(a->log.head == -1)
a->log.head = b->bp.addr;
if(b != a->log.tail)
a->log.tail = b;
return 0;
}
int
loadlog(Arena *a)
{
Blk *b;
vlong bp, ent, off, len;
uvlong bh;
char *p, *d;
int op, i, n;
bp = a->log.head;
Nextblk:
if((b = readblk(bp, 0)) == nil)
return -1;
cacheblk(b);
p = b->data;
bh = GBIT64(p + 0);
/* the hash covers the log and offset */
if(bh != siphash(p+8, Blkspc-8)){
werrstr("corrupt log");
return -1;
}
for(i = Loghdsz; i < Logspc; i += n){
d = b->data + i;
ent = GBIT64(d);
op = ent & 0xff;
off = ent & ~0xff;
n = (op & Log2w) ? 16 : 8;
switch(op){
case LogEnd:
dprint("log@%d: end\n", i);
/*
* since we want the next insertion to overwrite
* this, don't include the size in this entry.
*/
b->logsz = i;
return 0;
case LogChain:
bp = off & ~0xff;
dprint("log@%d: chain %llx\n", i, bp);
b->logsz = i+n;
goto Nextblk;
break;
case LogFlush:
dprint("log@%d: flush: %llx\n", i, off>>8);
fs->nextgen = (off >> 8)+1;
break;
case LogAlloc:
case LogAlloc1:
len = (op & Log2w) ? GBIT64(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 & Log2w) ? GBIT64(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, bp, nb, graft, oldhd;
int i, n, sz;
Blk *hd, *ab, *b;
Oplog ol;
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((bp = blkalloc_lk(a)) == -1)
return -1;
if((b = mallocz(sizeof(Blk), 1)) == nil)
return -1;
b->type = Tlog;
b->flag = Bdirty;
b->bp.addr = bp;
b->ref = 1;
b->data = b->buf + Hdrsz;
b->logsz = Loghdsz;
PBIT64(b->data+b->logsz, (uvlong)LogEnd);
finalize(b);
if(syncblk(b) == -1){
free(b);
return -1;
}
graft = b->bp.addr;
if(a->log.tail != nil){
finalize(a->log.tail);
if(syncblk(a->log.tail) == -1){
free(b);
return -1;
}
}
a->log.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;
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++;
}
if((b = newblk(Tlog)) == nil){
free(log);
return -1;
}
hd = b;
ol.hash = -1;
ol.head = b->bp.addr;
ol.tail = b;
b->logsz = Loghdsz;
for(i = 0; i < n; i++)
if((b = logappend(&ol, a, log[i].off, log[i].len, LogFree)) == nil)
return -1;
p = b->data + b->logsz;
PBIT64(p, LogChain|graft);
free(log);
finalize(b);
if(syncblk(b) == -1)
return -1;
oldhd = a->log.head;
a->log.head = hd->bp.addr;
a->log.hash = blkhash(hd);
ab = a->b;
PBIT64(ab->data + 0, a->log.head);
PBIT64(ab->data + 8, a->log.hash);
finalize(ab);
if(syncblk(ab) == -1)
return -1;
if(oldhd != -1){
for(bp = oldhd; bp != -1; bp = nb){
nb = -1;
if((b = readblk(bp, 0)) == nil)
return -1;
for(i = Loghdsz; i < Logspc; i += n){
p = b->data + i;
v = GBIT64(p);
n = (v & Log2w) ? 16 : 8;
if((v&0xff) == LogChain){
nb = v & ~0xff;
break;
}else if((v&0xff) == LogEnd){
nb = -1;
break;
}
}
lock(a);
if(blkdealloc_lk(bp) == -1){
unlock(a);
return -1;
}
unlock(a);
}
}
finalize(a->log.tail);
if(syncblk(a->log.tail) == -1)
return -1;
return 0;
}
/*
* Allocate from an arena, with lock
* held. May be called recursively, 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){
unlock(a);
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);
}
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, LogFree) == -1)
goto out;
r = 0;
out:
return r;
}
static vlong
blkalloc(void)
{
Arena *a;
vlong b;
int tries;
tries = 0;
Again:
a = pickarena();
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, LogAlloc) == -1){
unlock(a);
return -1;
}
unlock(a);
return b;
}
Blk*
newblk(int t)
{
Blk *b;
vlong bp;
if((bp = blkalloc()) == -1)
return nil;
if((b = lookupblk(bp)) == nil){
if((b = mallocz(sizeof(Blk), 1)) == nil)
return nil;
/*
* If the block is cached,
* then the cache holds a ref
* to the block, so we only
* want to reset the refs
* on an allocation.
*/
b->ref = 1;
b->cnext = nil;
b->cprev = nil;
b->hnext = nil;
}
b->type = t;
b->bp.addr = bp;
b->bp.hash = -1;
b->bp.gen = fs->nextgen;
b->data = b->buf + Hdrsz;
b->fnext = nil;
b->flag = Bdirty;
b->nval = 0;
b->valsz = 0;
b->nbuf = 0;
b->bufsz = 0;
b->logsz = 0;
b->lognxt = 0;
dprint("new block %B from %p, flag=%x\n", b->bp, getcallerpc(&t), b->flag);
return cacheblk(b);
}
char*
fillsuper(Blk *b)
{
char *p;
assert(b->type == Tsuper);
p = b->data;
lock(b);
b->flag |= Bdirty;
unlock(b);
memcpy(p, "gefs0001", 8); p += 8;
PBIT32(p, 0); p += 4; /* dirty */
PBIT32(p, Blksz); p += 4;
PBIT32(p, Bufspc); p += 4;
PBIT32(p, Hdrsz); p += 4;
PBIT32(p, fs->snap.ht); p += 4;
PBIT64(p, fs->snap.bp.addr); p += 8;
PBIT64(p, fs->snap.bp.hash); p += 8;
PBIT64(p, fs->nextgen); p += 8;
PBIT32(p, fs->narena); p += 4;
PBIT64(p, fs->arenasz); p += 8;
PBIT64(p, fs->nextqid); p += 8;
return p;
}
void
finalize(Blk *b)
{
vlong h;
// assert((b->flag & Bfinal) == 0);
lock(b);
b->flag |= Bfinal;
if(b->type != Traw)
PBIT16(b->buf, b->type);
switch(b->type){
default:
case Tnone:
abort();
break;
case Tpivot:
PBIT16(b->buf+2, b->nval);
PBIT16(b->buf+4, b->valsz);
PBIT16(b->buf+6, b->nbuf);
PBIT16(b->buf+8, b->bufsz);
b->bp.hash = blkhash(b);
break;
case Tleaf:
PBIT16(b->buf+2, b->nval);
PBIT16(b->buf+4, b->valsz);
b->bp.hash = blkhash(b);
break;
case Tlog:
h = siphash(b->data + 8, Blkspc-8);
PBIT64(b->data, h);
case Traw:
b->bp.hash = blkhash(b);
break;
case Tsuper:
case Tarena:
break;
}
unlock(b);
}
Blk*
getblk(Bptr bp, int flg)
{
Blk *b;
if((b = lookupblk(bp.addr)) != nil)
return cacheblk(b);
qlock(&blklock);
if((b = lookupblk(bp.addr)) != nil){
cacheblk(b);
qunlock(&blklock);
return b;
}
if((b = readblk(bp.addr, flg)) == nil){
qunlock(&blklock);
return nil;
}
if(blkhash(b) != bp.hash){
fprint(2, "corrupt block %B: %llx != %llx\n", bp, blkhash(b), bp.hash);
qunlock(&blklock);
abort();
return nil;
}
b->bp.hash = bp.hash;
b->bp.gen = bp.gen;
cacheblk(b);
qunlock(&blklock);
return b;
}
Blk*
dupblk(vlong bp, uvlong bh)
{
USED(bp, bh);
return nil;
}
Blk*
refblk(Blk *b)
{
ainc(&b->ref);
return 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
putblk(Blk *b)
{
if(b == nil || adec(&b->ref) != 0)
return;
assert((b->flag & Bqueued) || !(b->flag & Bdirty));
free(b);
}
static void
deadlist(Bptr bp)
{
fprint(2, "cross-snap free: %B\n", bp);
}
void
freebp(Bptr bp)
{
Bfree *f;
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(Blk *b)
{
lock(b);
assert((b->flag & Bqueued) == 0);
b->freed = getcallerpc(&b);
unlock(b);
dprint("freeing block %B @ %ld, from 0x%p\n", b->bp, b->ref, getcallerpc(&b));
if(b->bp.gen == fs->nextgen)
freebp(b->bp);
else
deadlist(b->bp);
}
void
reclaimblk(Bptr bp)
{
Arena *a;
a = getarena(bp.addr);
lock(a);
blkdealloc_lk(bp.addr);
unlock(a);
}