ref: 40a7bbda7392fdc8183678ea82323cded91b14ce
parent: 1c52bff742ac452c853b93fa9a05b2ac0f243714
author: Ori Bernstein <ori@eigenstate.org>
date: Sun Oct 30 10:52:13 EDT 2022
fs: add 'dump' attach spec to mount snapshot dump
--- a/dat.h
+++ b/dat.h
@@ -103,6 +103,10 @@
Bcached = 1 << 3,
};
+enum {+ Qdump = 1ULL << 63,
+};
+
/* internal errors */
#define Efs (abort(), "fs broke")
extern char Eimpl[];
@@ -435,9 +439,10 @@
Rendez syncrz;
QLock snaplk; /* snapshot lock */
- Tree *osnap;
+ Tree *opensnap;
Lock mountlk;
Mount *mounts;
+ Mount *snapmnt;
Lock connlk;
Conn *conns;
--- a/fs.c
+++ b/fs.c
@@ -71,6 +71,23 @@
}
static void
+filldumpdir(Xdir *d)
+{+ memset(d, 0, sizeof(Xdir));
+ d->name = "/";
+ d->qid.path = Qdump;
+ d->qid.vers = fs->nextgen;
+ d->qid.type = QTDIR;
+ d->mode = 0555;
+ d->atime = 0;
+ d->mtime = 0;
+ d->length = 0;
+ d->uid = -1;
+ d->gid = -1;
+ d->muid = -1;
+}
+
+static void
freemsg(Fmsg *m)
{free(m->a);
@@ -202,17 +219,19 @@
static char*
-lookup(Fid *f, Key *k, Kvp *kv, char *buf, int nbuf)
+lookup(Mount *mnt, Key *k, Kvp *kv, char *buf, int nbuf)
{char *e;
Tree *r;
- if(f->mnt == nil)
+ if(mnt == nil)
return Eattach;
- lock(f->mnt);
- r = f->mnt->root;
+
+ lock(mnt);
+ r = mnt->root;
ainc(&r->memref);
- unlock(f->mnt);
+ unlock(mnt);
+
e = btlookup(r, k, kv, buf, nbuf);
closesnap(r);
return e;
@@ -268,7 +287,7 @@
PACK64(k.k+1, f->qpath);
PACK64(k.k+9, fb);
- e = lookup(f, &k, &kv, kvbuf, sizeof(kvbuf));
+ e = lookup(f->mnt, &k, &kv, kvbuf, sizeof(kvbuf));
if(e != nil){ if(e != Eexist){werrstr(e);
@@ -308,7 +327,7 @@
return -1;
t = nil;
if(fb < sz && (fo != 0 || n != Blksz)){- e = lookup(f, m, &kv, buf, sizeof(buf));
+ e = lookup(f->mnt, m, &kv, buf, sizeof(buf));
if(e == nil){bp = unpackbp(kv.v, kv.nv);
if((t = getblk(bp, GBraw)) == nil)
@@ -383,6 +402,10 @@
Mount *mnt;
Tree *t;
+ if(strcmp(name, "dump") == 0){+ ainc(&fs->snapmnt->ref);
+ return fs->snapmnt;
+ }
lock(&fs->mountlk);
for(mnt = fs->mounts; mnt != nil; mnt = mnt->next)
if(strcmp(name, mnt->name) == 0){@@ -849,20 +872,25 @@
goto Out;
}
- if((p = packdkey(dbuf, sizeof(dbuf), -1ULL, "")) == nil){- rerror(m, Elength);
- goto Out;
+ if(strcmp(m->aname, "dump") == 0){+ memset(&d, 0, sizeof(d));
+ filldumpdir(&d);
+ }else{+ if((p = packdkey(dbuf, sizeof(dbuf), -1ULL, "")) == nil){+ rerror(m, Elength);
+ goto Out;
+ }
+ dk.k = dbuf;
+ dk.nk = p - dbuf;
+ if((e = btlookup(mnt->root, &dk, &kv, kvbuf, sizeof(kvbuf))) != nil){+ rerror(m, e);
+ goto Out;
+ }
+ if(kv2dir(&kv, &d) == -1){+ rerror(m, Efs);
+ goto Out;
+ }
}
- dk.k = dbuf;
- dk.nk = p - dbuf;
- if((e = btlookup(mnt->root, &dk, &kv, kvbuf, sizeof(kvbuf))) != nil){- rerror(m, e);
- goto Out;
- }
- if(kv2dir(&kv, &d) == -1){- rerror(m, Efs);
- goto Out;
- }
if((de = getdent(-1, &d)) == nil){rerror(m, Efs);
goto Out;
@@ -905,7 +933,7 @@
return Elength;
k.k = kbuf;
k.nk = p - kbuf;
- if((e = lookup(f, &k, &kv, buf, nbuf)) != nil)
+ if((e = lookup(f->mnt, &k, &kv, buf, nbuf)) != nil)
return e;
if((*name = unpackdkey(kv.v, kv.nv, qpath)) == nil)
return Efs;
@@ -920,6 +948,7 @@
vlong up, prev;
Fid *o, *f;
Dent *dent;
+ Mount *mnt;
Fcall r;
Xdir d;
Kvp kv;
@@ -936,6 +965,7 @@
return;
}
e = nil;
+ mnt = o->mnt;
up = o->qpath;
prev = o->qpath;
rlock(o->dent);
@@ -952,30 +982,47 @@
return;
}
name = m->wname[i];
- if(strcmp(m->wname[i], "..") == 0){- if((e = findparent(o, &prev, &name, kbuf, sizeof(kbuf))) != nil){- rerror(m, e);
+ if(d.qid.path == Qdump){+ if((mnt = getmount(m->wname[i])) == nil){putfid(o);
return;
}
+ if((p = packdkey(kbuf, sizeof(kbuf), -1ULL, "")) == nil){+ clunkmount(mnt);
+ putfid(o);
+ return;
+ }
+ }else{+ if(strcmp(m->wname[i], "..") == 0){+ if(o->pqpath == Qdump){+ mnt = fs->snapmnt;
+ filldumpdir(&d);
+ goto Found;
+ }else if((e = findparent(o, &prev, &name, kbuf, sizeof(kbuf))) != nil){+ rerror(m, e);
+ putfid(o);
+ return;
+ }
+ }
+ if((p = packdkey(kbuf, sizeof(kbuf), prev, name)) == nil){+ rerror(m, Elength);
+ putfid(o);
+ return;
+ }
}
- if((p = packdkey(kbuf, sizeof(kbuf), prev, name)) == nil){- rerror(m, Elength);
- putfid(o);
- return;
- }
k.k = kbuf;
k.nk = p - kbuf;
- if((e = lookup(o, &k, &kv, kvbuf, sizeof(kvbuf))) != nil)
+ if((e = lookup(mnt, &k, &kv, kvbuf, sizeof(kvbuf))) != nil)
break;
- duid = d.uid;
- dgid = d.gid;
- dmode = d.mode;
if(kv2dir(&kv, &d) == -1){rerror(m, Efs);
putfid(o);
return;
}
+Found:
+ duid = d.uid;
+ dgid = d.gid;
+ dmode = d.mode;
up = prev;
prev = d.qid.path;
r.wqid[i] = d.qid;
@@ -996,14 +1043,24 @@
putfid(o);
}
if(i > 0 && i == m->nwname){- dent = getdent(up, &d);
+ lock(f);
+ if(up == Qdump)
+ dent = getdent(-1ULL, &d);
+ else
+ dent = getdent(up, &d);
if(dent == nil){if(f != o)
clunkfid(m->conn, f);
rerror(m, Enomem);
+ unlock(f);
putfid(f);
return;
}
+ if(mnt != f->mnt){+ clunkmount(f->mnt);
+ ainc(&mnt->ref);
+ f->mnt = mnt;
+ }
f->qpath = r.wqid[i-1].path;
f->pqpath = up;
f->dent = dent;
@@ -1010,6 +1067,7 @@
f->duid = duid;
f->dgid = dgid;
f->dmode = dmode;
+ unlock(f);
}
respond(m, &r);
putfid(f);
@@ -1063,7 +1121,7 @@
}
de = f->dent;
wlock(de);
- if(de->qid.type & QTAUTH){+ if((de->qid.type & QTAUTH) || (de->qid.path & Qdump)){rerror(m, Emode);
goto Out;
}
@@ -1256,7 +1314,6 @@
rerror(m, Efid);
return;
}
-
lock(f);
if(f->scan != nil){btdone(f->scan);
@@ -1486,16 +1543,21 @@
rerror(m, Efid);
return;
}
- if((e = lookup(f, f->dent, &kv, buf, sizeof(buf))) != nil){- rerror(m, e);
- putfid(f);
- return;
+
+ if((f->qpath & Qdump) != 0){+ filldumpdir(&d);
+ }else{+ if((e = lookup(f->mnt, f->dent, &kv, buf, sizeof(buf))) != nil){+ rerror(m, e);
+ putfid(f);
+ return;
+ }
+ if(kv2dir(&kv, &d) == -1){+ rerror(m, Efs);
+ putfid(f);
+ return;
+ }
}
- if(kv2dir(&kv, &d) == -1){- rerror(m, Efs);
- putfid(f);
- return;
- }
if(fsaccess(f, d.mode, d.uid, d.gid, mbits) == -1){rerror(m, Eperm);
putfid(f);
@@ -1590,6 +1652,73 @@
}
static char*
+readsnap(Fmsg *m, Fid *f, Fcall *r)
+{+ char pfx[1], *p, *e;
+ int n, ns, done;
+ Scan *s;
+ Xdir d;
+
+ s = f->scan;
+ if(s != nil && s->offset != 0 && s->offset != m->offset)
+ return Edscan;
+ if(s == nil || m->offset == 0){+ if((s = mallocz(sizeof(Scan), 1)) == nil)
+ return Enomem;
+ pfx[0] = Klabel;
+ if((e = btscan(&fs->snap, s, pfx, 1)) != nil){+ btdone(s);
+ free(s);
+ return e;
+ }
+
+ lock(f);
+ if(f->scan != nil){+ btdone(f->scan);
+ free(f->scan);
+ }
+ f->scan = s;
+ unlock(f);
+ }
+ if(s->done){+ r->count = 0;
+ return nil;
+ }
+ p = r->data;
+ n = m->count;
+ d = f->dent->Xdir;
+ if(s->overflow){+ memcpy(d.name, s->kv.k+1, s->kv.nk-1);
+ d.name[s->kv.nk-1] = 0;
+ d.qid.path = UNPACK64(s->kv.v + 1);
+ if((ns = dir2statbuf(&d, p, n)) == -1){+ r->count = 0;
+ return nil;
+ }
+ s->overflow = 0;
+ p += ns;
+ n -= ns;
+ }
+ while(1){+ if((e = btnext(s, &s->kv, &done)) != nil)
+ return e;
+ if(done)
+ break;
+ memcpy(d.name, s->kv.k+1, s->kv.nk-1);
+ d.name[s->kv.nk-1] = 0;
+ d.qid.path = UNPACK64(s->kv.v + 1);
+ if((ns = dir2statbuf(&d, p, n)) == -1){+ s->overflow = 1;
+ break;
+ }
+ p += ns;
+ n -= ns;
+ }
+ r->count = p - r->data;
+ return nil;
+}
+
+static char*
readdir(Fmsg *m, Fid *f, Fcall *r)
{char pfx[Dpfxsz], *p, *e;
@@ -1705,6 +1834,8 @@
}
if(f->dent->qid.type & QTAUTH)
e = readauth(m, f, &r);
+ else if(f->dent->qid.path == Qdump)
+ e = readsnap(m, f, &r);
else if(f->dent->qid.type & QTDIR)
e = readdir(m, f, &r);
else
@@ -1950,15 +2081,11 @@
}
break;
case AOsync:
- if(m->a->fd != -1)
- fprint(m->a->fd, "syncing [readonly: %d]\n", m->a->halt);
if(m->a->halt)
ainc(&fs->rdonly);
for(mnt = fs->mounts; mnt != nil; mnt = mnt->next)
updatemount(mnt);
sync();
- if(m->a->fd != -1)
- fprint(m->a->fd, "sync done\n");
freemsg(m);
break;
case AOsnap:
--- a/load.c
+++ b/load.c
@@ -46,6 +46,7 @@
void
loadfs(char *dev)
{+ Mount *mnt;
Fshdr fi;
Arena *a;
char *e;
@@ -52,7 +53,17 @@
Tree *t;
int i, k;
- fs->osnap = nil;
+ if((mnt = mallocz(sizeof(*mnt), 1)) == nil)
+ sysfatal("malloc: %r");+ if((mnt->name = strdup("dump")) == nil)+ sysfatal("malloc: %r");+ mnt->ref = 1;
+ mnt->root = nil;
+ mnt->gen = -1;
+ mnt->root = &fs->snap;
+
+ fs->opensnap = nil;
+ fs->snapmnt = mnt;
fs->gotinfo = 0;
fs->narena = 1;
if((fs->fd = open(dev, ORDWR)) == -1)
--- a/snap.c
+++ b/snap.c
@@ -175,7 +175,7 @@
Key k;
qlock(&fs->snaplk);
- for(t = fs->osnap; t != nil; t = t->snext){+ for(t = fs->opensnap; t != nil; t = t->snext){ if(t->gen == id){ainc(&t->memref);
qunlock(&fs->snaplk);
@@ -195,8 +195,8 @@
if(unpacktree(t, kv.v, kv.nv) == nil)
goto Error;
t->memref = 1;
- t->snext = fs->osnap;
- fs->osnap = t;
+ t->snext = fs->opensnap;
+ fs->opensnap = t;
qunlock(&fs->snaplk);
return t;
@@ -225,8 +225,8 @@
//FIXME: putblk(ins);
}
- p = &fs->osnap;
- for(te = fs->osnap; te != nil; te = te->snext){+ p = &fs->opensnap;
+ for(te = fs->opensnap; te != nil; te = te->snext){if(te == t)
break;
p = &te->snext;
@@ -275,6 +275,8 @@
char *p, *e, kbuf[Keymax], vbuf[Snapsz];
Msg m;
+ if(strcmp(name, "dump") == 0)
+ return Ename;
if(op == Oinsert)
e = refsnap(id);
else
@@ -399,7 +401,7 @@
return nil;
gen = aincv(&fs->nextgen, 1);
memset(&r->lk, 0, sizeof(r->lk));
- r->snext = fs->osnap;
+ r->snext = fs->opensnap;
r->memref = 1;
r->ref = 0;
r->ht = t->ht;
@@ -414,7 +416,7 @@
r->dead[i].head.gen = -1;
r->dead[i].ins = nil;
}
- fs->osnap = r;
+ fs->opensnap = r;
return r;
}