ref: d1a51cc02a74d6f9b19451d1a16b92c7b83b2889
parent: 3b48c49025b592ef59724e864e0c01d03680b070
author: Ori Bernstein <ori@eigenstate.org>
date: Sun May 7 11:56:09 EDT 2023
fs: handle clobbering and renaming files more correctly this change addresses two issues: first, when creating a file, we used to simply send a Oinsert down the tree, which meant that if the message had propagated to a leaf, and we did a remove for each fid that had a reference, we may remove the first instance, and then blow up that a second did not exist. that when removing it via 2 fids, we may remove the first and then assert when we remove the second. second, when renaming over an existing dir, we may leak the old blocks and lose the '..' link that we need to refer to files relative to the dir.
--- a/dat.h
+++ b/dat.h
@@ -57,6 +57,7 @@
Offksz = 17, /* type, qid, off */
Snapsz = 9, /* tag, snapid */
Dpfxsz = 9, /* directory prefix */
+ Upksz = 9, /* directory prefix */
Dlksz = 1+8+8, /* tag, death, birth */
Dlvsz = Ptrsz+Ptrsz, /* hd,tl of deadlist */
Dlkvpsz = Dlksz+Dlvsz, /* full size of dlist kvp */
@@ -96,7 +97,7 @@
/* fs keys */
Kdat, /* qid[8] off[8] => ptr: pointer to data page */
Kent, /* pqid[8] name[n] => dir[n]: serialized Dir */
- Ksuper, /* qid[8] => Kent: parent dir */
+ Kup, /* qid[8] => Kent: parent dir */
/* snapshot keys */
Klabel, /* name[] => snapid[]: snapshot label */
@@ -258,6 +259,7 @@
Oinsert, /* new kvp */
Odelete, /* delete kvp */
Oclearb, /* free block ptr if exists */
+ Oclobber, /* remove file if it exists */
Owstat, /* update kvp dirent */
Orefsnap, /* increment snap refcount by delta */
Nmsgtype, /* maximum message type */
--- a/dump.c
+++ b/dump.c
@@ -10,6 +10,31 @@
char spc[128];
static int
+walk1(Tree *t, vlong up, char *name, Qid *qid, vlong *len)
+{+ char *p, kbuf[Keymax], rbuf[Kvmax];
+ int err;
+ Xdir d;
+ Kvp kv;
+ Key k;
+
+ err = 0;
+ if((p = packdkey(kbuf, sizeof(kbuf), up, name)) == nil)
+ return -1;
+ k.k = kbuf;
+ k.nk = p - kbuf;
+ if(err)
+ return -1;
+ if(btlookup(t, &k, &kv, rbuf, sizeof(rbuf)) != nil)
+ return -1;
+ if(kv2dir(&kv, &d) == -1)
+ return -1;
+ *qid = d.qid;
+ *len = d.length;
+ return 0;
+}
+
+static int
showkey(Fmt *fmt, Key *k)
{int n;
@@ -34,7 +59,7 @@
case Ksnap: /* name[n] => tree[24]: snapshot root */
n = fmtprint(fmt, "snap id:%lld", UNPACK64(k->k+1));
break;
- case Ksuper: /* qid[8] => pqid[8]: parent dir */
+ case Kup: /* qid[8] => pqid[8]: parent dir */
n = fmtprint(fmt, "up dir:%llx", UNPACK64(k->k+1));
break;
case Kslink:
@@ -142,7 +167,7 @@
case Klabel:
n = fmtprint(fmt, "snap id:\"%lld\"", UNPACK64(v->v+1));
break;
- case Ksuper: /* qid[8] => pqid[8]: parent dir */
+ case Kup: /* qid[8] => pqid[8]: parent dir */
n = fmtprint(fmt, "super dir:%llx, name:\"%.*s\")", UNPACK64(v->v+1), v->nv-11, v->v+11);
break;
case Kslink:
--- a/fns.h
+++ b/fns.h
@@ -11,6 +11,7 @@
extern int debug;
extern int permissive;
extern char* reamuser;
+extern Blk* blkbuf;
#define UNPACK8(p) (((uchar*)(p))[0])
#define UNPACK16(p) ((((uchar*)(p))[0]<<8)|(((uchar*)(p))[1]))
@@ -113,6 +114,7 @@
void showblk(int, Blk*, char*, int);
void showbp(int, Bptr, int);
void showtreeroot(int, Tree*);
+void showballoc(int, char**, int);
void showdlist(int, char**, int);
void showtree(int, char**, int);
void showsnap(int, char**, int);
--- a/fs.c
+++ b/fs.c
@@ -9,8 +9,31 @@
#include "fns.h"
#include "atomic.h"
-static char* clearb(Fid*, vlong, vlong);
+static int
+walk1(Tree *t, vlong up, char *name, Qid *qid, vlong *len)
+{+ char *p, kbuf[Keymax], rbuf[Kvmax];
+ int err;
+ Xdir d;
+ Kvp kv;
+ Key k;
+ err = 0;
+ if((p = packdkey(kbuf, sizeof(kbuf), up, name)) == nil)
+ return -1;
+ k.k = kbuf;
+ k.nk = p - kbuf;
+ if(err)
+ return -1;
+ if(btlookup(t, &k, &kv, rbuf, sizeof(rbuf)) != nil)
+ return -1;
+ if(kv2dir(&kv, &d) == -1)
+ return -1;
+ *qid = d.qid;
+ *len = d.length;
+ return 0;
+}
+
static void
snapfs(int fd, char *old, char *new)
{@@ -250,22 +273,22 @@
* the range listed.
*/
static char*
-clearb(Fid *f, vlong o, vlong sz)
+clearb(Mount *mnt, vlong qid, vlong off, vlong len)
{char *e, buf[Offksz];
Msg m;
- o &= ~(Blksz - 1);
- for(; o < sz; o += Blksz){+ off &= ~(Blksz - 1);
+ for(; off < len; off += Blksz){m.k = buf;
m.nk = sizeof(buf);
m.op = Oclearb;
m.k[0] = Kdat;
- PACK64(m.k+1, f->qpath);
- PACK64(m.k+9, o);
+ PACK64(m.k+1, qid);
+ PACK64(m.k+9, off);
m.v = nil;
m.nv = 0;
- if((e = upsert(f->mnt, &m, 1)) != nil)
+ if((e = upsert(mnt, &m, 1)) != nil)
return e;
}
return nil;
@@ -1117,11 +1140,12 @@
static void
fswstat(Fmsg *m)
{- char *p, *e, strs[65535], rnbuf[Kvmax], opbuf[Kvmax];
+ char rnbuf[Kvmax], opbuf[Kvmax], upbuf[Upksz];
+ char *p, *e, strs[65535];
int op, nm, rename;
Fcall r;
Dent *de;
- Msg mb[2];
+ Msg mb[3];
Xdir n;
Dir d;
Fid *f;
@@ -1285,12 +1309,12 @@
/* update directory entry */
nm = 0;
if(rename && !de->gone){- mb[nm].op = Odelete;
+ mb[nm].op = Oclobber;
mb[nm].Key = de->Key;
mb[nm].v = nil;
mb[nm].nv = 0;
nm++;
-
+
mb[nm].op = Oinsert;
if(dir2kv(f->pqpath, &n, &mb[nm], rnbuf, sizeof(rnbuf)) == -1){rerror(m, Efs);
@@ -1298,6 +1322,16 @@
}
k = mb[nm].Key;
nm++;
+
+ if(de->qid.type & QTDIR){+ packsuper(upbuf, sizeof(upbuf), f->qpath);
+ mb[nm].op = Oinsert;
+ mb[nm].k = upbuf;
+ mb[nm].nk = Upksz;
+ mb[nm].v = mb[nm-1].k;
+ mb[nm].nv = mb[nm-1].nk;
+ nm++;
+ }
}else{opbuf[0] = op;
mb[nm].op = Owstat;
@@ -1306,6 +1340,7 @@
mb[nm].nv = p - opbuf;
nm++;
}
+ assert(nm <= nelem(mb));
if((e = upsert(f->mnt, mb, nm)) != nil){rerror(m, e);
goto Out;
@@ -1352,11 +1387,13 @@
{char *p, *e, buf[Kvmax], upkbuf[Keymax], upvbuf[Inlmax];
Dent *de;
+ vlong oldlen;
+ Qid old;
Fcall r;
Msg mb[2];
Fid *f;
Xdir d;
- int nm;
+ int nm, clobber;
if(okname(m->name) == -1){rerror(m, Ename);
@@ -1372,6 +1409,11 @@
return;
}
de = f->dent;
+
+ clobber = 0;
+ if(walk1(f->mnt->root, f->qpath, m->name, &old, &oldlen) == 0)
+ clobber = 1;
+
rlock(de);
if(fsaccess(f, de->mode, de->uid, de->gid, DMWRITE) == -1){runlock(de);
@@ -1438,11 +1480,17 @@
rerror(m, Enomem);
putfid(f);
return;
- }else{- wlock(de);
- de->length = 0;
+ }
+
+ wlock(de);
+ if(clobber && (e = clearb(f->mnt, old.path, 0, oldlen)) != nil){+ rerror(m, e);
wunlock(de);
+ putfid(f);
+ return;
}
+ de->length = 0;
+ wunlock(de);
lock(f);
if(f->mode != -1){@@ -1456,17 +1504,6 @@
f->pqpath = f->qpath;
f->qpath = d.qid.path;
f->dent = de;
- wlock(de);
- de->gone = 0;
- if((e = clearb(f, 0, de->length)) != nil){- unlock(f);
- clunkdent(de);
- rerror(m, e);
- putfid(f);
- return;
- }
- de->length = 0;
- wunlock(de);
unlock(f);
r.type = Rcreate;
@@ -1500,8 +1537,9 @@
static void
fsremove(Fmsg *m)
{+ char upbuf[Upksz];
Fcall r;
- Msg mb;
+ Msg mb[2];
Fid *f;
char *e;
@@ -1522,15 +1560,21 @@
e = Eperm;
goto Error;
}
- mb.op = Odelete;
- mb.k = f->dent->k;
- mb.nk = f->dent->nk;
- mb.nv = 0;
+ mb[0].op = Odelete;
+ mb[0].k = f->dent->k;
+ mb[0].nk = f->dent->nk;
+ mb[0].nv = 0;
- if((e = upsert(f->mnt, &mb, 1)) != nil)
+ packsuper(upbuf, sizeof(upbuf), f->qpath);
+ mb[1].op = Oclobber;
+ mb[1].k = upbuf;
+ mb[1].nk = Upksz;
+ mb[1].nv = 0;
+
+ if((e = upsert(f->mnt, mb, 1)) != nil)
goto Error;
if(f->dent->qid.type == QTFILE){- e = clearb(f, 0, f->dent->length);
+ e = clearb(f->mnt, f->qpath, 0, f->dent->length);
if(e != nil)
goto Error;
}
@@ -1626,7 +1670,7 @@
mb.nk = f->dent->nk;
mb.v = buf;
mb.nv = p - buf;
- clearb(f, 0, f->dent->length);
+ clearb(f->mnt, f->qpath, 0, f->dent->length);
if((e = upsert(f->mnt, &mb, 1)) != nil){wunlock(f->dent);
rerror(m, e);
--- a/pack.c
+++ b/pack.c
@@ -188,7 +188,7 @@
err = 0;
ep = p + sz;
- p = pack8(&err, p, ep, Ksuper);
+ p = pack8(&err, p, ep, Kup);
p = pack64(&err, p, ep, up);
if(err)
return nil;
--- a/tree.c
+++ b/tree.c
@@ -403,6 +403,7 @@
switch(m->op){case Oclearb:
case Odelete:
+ case Oclobber:
assert(keycmp(kv, m) == 0);
return 0;
case Oinsert:
@@ -480,7 +481,7 @@
* new values must always start as
* an insertion, mutations come after.
*/
- if(m.op == Oclearb)
+ if(m.op == Oclearb || m.op == Oclobber)
ok = 0;
else if(m.op != Oinsert){fprint(2, "%d(/%d), %d: %M not insert\n", i, b->nval, j, &m);
@@ -516,7 +517,7 @@
ok = 1;
cpkvp(&v, &m, buf, sizeof(buf));
p->pullsz += msgsz(&m);
- if(m.op == Oclearb)
+ if(m.op == Oclearb || m.op == Oclobber)
continue;
if(m.op != Oinsert){fprint(2, "%d(/%d), %d: %M not insert\n", i, b->nval, j, &m);
@@ -677,10 +678,10 @@
* new values must always start as
* an insertion, mutations come after.
*/
- if(m.op == Oclearb)
+ if(m.op == Oclearb || m.op == Oclobber)
ok = 0;
else if(m.op != Oinsert){- fprint(2, "%d(/%d), %d: %M not insert\n", i, b->nval, j, &m);
+ fprint(2, "%d(/%d), %d: expected insert, got %M\n", i, b->nval, j, &m);
abort();
}
cpkvp(&v, &m, buf, sizeof(buf));