ref: 1dbb193077af7ba6ff7fb70a4dd465480764382e
dir: /os/port/devds.c/
/* * (file system) device subsystems * '#k'. * Follows device config in Ken's file server. * Builds mirrors, device cats, interleaving, and partition of devices out of * other (inner) devices. * * This code is from Plan 9, and subject to the Lucent Public License 1.02. * Only the name changed for Inferno (name clash). */ #include "u.h" #include "../port/lib.h" #include "mem.h" #include "dat.h" #include "fns.h" #include "io.h" #include "ureg.h" #include "../port/error.h" enum { Fmirror, // mirror of others Fcat, // catenation of others Finter, // interleaving of others Fpart, // part of others Blksize = 8*1024, // for Finter only Maxconf = 1024, // max length for config Nfsdevs = 64, Ndevs = 8, Qtop = 0, // top dir (contains "ds") Qdir = 1, // actual dir Qctl = 2, // ctl file Qfirst = 3, // first fs file }; #define Cfgstr "fsdev:\n" typedef struct Fsdev Fsdev; struct Fsdev { int type; char *name; // name for this fsdev vlong start; // start address (for Fpart) vlong size; // min(idev sizes) int ndevs; // number of inner devices char *iname[Ndevs]; // inner device names Chan *idev[Ndevs]; // inner devices vlong isize[Ndevs]; // sizes for inneer devices }; /* * Once configured, a fsdev is never removed. The name of those * configured is never nil. We have no locks here. */ static Fsdev fsdev[Nfsdevs]; static Qid tqid = {Qtop, 0, QTDIR}; static Qid dqid = {Qdir, 0, QTDIR}; static Qid cqid = {Qctl, 0, 0}; static Cmdtab configs[] = { Fmirror,"mirror", 0, Fcat, "cat", 0, Finter, "inter", 0, Fpart, "part", 5, }; static char confstr[Maxconf]; static int configed; static Fsdev* path2dev(int i, int mustexist) { if (i < 0 || i >= nelem(fsdev)) error("bug: bad index in devfsdev"); if (mustexist && fsdev[i].name == nil) error(Enonexist); if (fsdev[i].name == nil) return nil; else return &fsdev[i]; } static Fsdev* devalloc(void) { int i; for (i = 0; i < nelem(fsdev); i++) if (fsdev[i].name == nil) break; if (i == nelem(fsdev)) error(Enodev); return &fsdev[i]; } static void setdsize(Fsdev* mp) { uchar buf[128]; /* old DIRLEN plus a little should be plenty */ int i; Chan *mc; Dir d; long l; if (mp->type != Fpart){ mp->start= 0; mp->size = 0LL; } for (i = 0; i < mp->ndevs; i++){ mc = mp->idev[i]; l = devtab[mc->type]->stat(mc, buf, sizeof(buf)); convM2D(buf, l, &d, nil); mp->isize[i] = d.length; switch(mp->type){ case Fmirror: if (mp->size == 0LL || mp->size > d.length) mp->size = d.length; break; case Fcat: mp->size += d.length; break; case Finter: // truncate to multiple of Blksize d.length = (d.length & ~(Blksize-1)); mp->isize[i] = d.length; mp->size += d.length; break; case Fpart: // should raise errors here? if (mp->start > d.length) mp->start = d.length; if (d.length < mp->start + mp->size) mp->size = d.length - mp->start; break; } } } static void mpshut(Fsdev *mp) { int i; char *nm; nm = mp->name; mp->name = nil; // prevent others from using this. if (nm) free(nm); for (i = 0; i < mp->ndevs; i++){ if (mp->idev[i] != nil) cclose(mp->idev[i]); if (mp->iname[i]) free(mp->iname[i]); } memset(mp, 0, sizeof(*mp)); } static void mconfig(char* a, long n) // "name idev0 idev1" { static QLock lck; Cmdbuf *cb; Cmdtab *ct; Fsdev *mp; int i; char *oldc; char *c; vlong size, start; size = 0; start = 0; if (confstr[0] == 0) seprint(confstr, confstr+sizeof(confstr), Cfgstr); oldc = confstr + strlen(confstr); qlock(&lck); if (waserror()){ *oldc = 0; qunlock(&lck); nexterror(); } cb = parsecmd(a, n); if(waserror()){ free(cb); nexterror(); } c = oldc; for (i = 0; i < cb->nf; i++) c = seprint(c, confstr+sizeof(confstr), "%s ", cb->f[i]); *(c-1) = '\n'; ct = lookupcmd(cb, configs, nelem(configs)); cb->f++; // skip command cb->nf--; if (ct->index == Fpart){ size = strtoll(cb->f[3], nil, 10); cb->nf--; start = strtoll(cb->f[2], nil, 10); cb->nf--; } for (i = 0; i < nelem(fsdev); i++) if (fsdev[i].name != nil && strcmp(fsdev[i].name, cb->f[0])==0) error(Eexist); if (cb->nf - 1 > Ndevs) error("too many devices; fix me"); for (i = 0; i < cb->nf; i++) validname(cb->f[i], (i != 0)); mp = devalloc(); if(waserror()){ mpshut(mp); nexterror(); } mp->type = ct->index; if (mp->type == Fpart){ mp->size = size; mp->start = start; } kstrdup(&mp->name, cb->f[0]); for (i = 1; i < cb->nf; i++){ kstrdup(&mp->iname[i-1], cb->f[i]); mp->idev[i-1] = namec(mp->iname[i-1], Aopen, ORDWR, 0); if (mp->idev[i-1] == nil) error(Egreg); mp->ndevs++; } setdsize(mp); poperror(); free(cb); poperror(); poperror(); configed = 1; qunlock(&lck); } static void rdconf(void) { int mustrd; char *s; char *c; char *p; char *e; Chan *cc; s = getconf("fsconfig"); if (s == nil){ mustrd = 0; s = "/dev/sdC0/fscfg"; } else mustrd = 1; if (waserror()){ configed = 1; if (!mustrd) return; nexterror(); } cc = namec(s, Aopen, OREAD, 0); if(waserror()){ cclose(cc); nexterror(); } devtab[cc->type]->read(cc, confstr, sizeof(confstr), 0); poperror(); cclose(cc); if (strncmp(confstr, Cfgstr, strlen(Cfgstr)) != 0) error("config string must start with `fsdev:'"); kstrdup(&c, confstr + strlen(Cfgstr)); if(waserror()){ free(c); nexterror(); } memset(confstr, 0, sizeof(confstr)); for (p = c; p != nil && *p != 0; p = e){ e = strchr(p, '\n'); if (e == p){ e++; continue; } if (e == nil) e = p + strlen(p); mconfig(p, e - p); } poperror(); poperror(); } static int mgen(Chan *c, char*, Dirtab*, int, int i, Dir *dp) { Qid qid; Fsdev *mp; if (c->qid.path == Qtop){ switch(i){ case DEVDOTDOT: devdir(c, tqid, "#k", 0, eve, DMDIR|0775, dp); return 1; case 0: devdir(c, dqid, "ds", 0, eve, DMDIR|0775, dp); return 1; default: return -1; } } if (c->qid.path != Qdir){ switch(i){ case DEVDOTDOT: devdir(c, dqid, "ds", 0, eve, DMDIR|0775, dp); return 1; default: return -1; } } switch(i){ case DEVDOTDOT: devdir(c, tqid, "#k", 0, eve, DMDIR|0775, dp); return 1; case 0: devdir(c, cqid, "ctl", 0, eve, 0664, dp); return 1; } i--; // for ctl qid.path = Qfirst + i; qid.vers = 0; qid.type = 0; mp = path2dev(i, 0); if (mp == nil) return -1; kstrcpy(up->genbuf, mp->name, sizeof(up->genbuf)); devdir(c, qid, up->genbuf, mp->size, eve, 0664, dp); return 1; } static Chan* mattach(char *spec) { *confstr = 0; return devattach(L'k', spec); } static Walkqid* mwalk(Chan *c, Chan *nc, char **name, int nname) { if (!configed) rdconf(); return devwalk(c, nc, name, nname, 0, 0, mgen); } static int mstat(Chan *c, uchar *db, int n) { Dir d; Fsdev *mp; int p; p = c->qid.path; memset(&d, 0, sizeof(d)); switch(p){ case Qtop: devdir(c, tqid, "#k", 0, eve, DMDIR|0775, &d); break; case Qdir: devdir(c, dqid, "ds", 0, eve, DMDIR|0775, &d); break; case Qctl: devdir(c, cqid, "ctl", 0, eve, 0664, &d); break; default: mp = path2dev(p - Qfirst, 1); devdir(c, c->qid, mp->name, mp->size, eve, 0664, &d); } n = convD2M(&d, db, n); if (n == 0) error(Ebadarg); return n; } static Chan* mopen(Chan *c, int omode) { if((c->qid.type & QTDIR) && omode != OREAD) error(Eperm); if (omode & OTRUNC) omode &= ~OTRUNC; c->mode = openmode(omode); c->flag |= COPEN; c->offset = 0; return c; } static void mclose(Chan*) { // that's easy } static long catio(Fsdev *mp, int isread, void *a, long n, vlong off) { int i; Chan* mc; long l, wl, res; //print("catio %d %p %ld %lld\n", isread, a, n, off); res = n; for (i = 0; n >= 0 && i < mp->ndevs ; i++){ mc = mp->idev[i]; if (off > mp->isize[i]){ off -= mp->isize[i]; continue; } if (off + n > mp->isize[i]) l = mp->isize[i] - off; else l = n; //print("\tdev %d %p %ld %lld\n", i, a, l, off); if (isread) wl = devtab[mc->type]->read(mc, a, l, off); else wl = devtab[mc->type]->write(mc, a, l, off); if (wl != l) error("#k: write failed"); a = (char*)a + l; off = 0; n -= l; } //print("\tres %ld\n", res - n); return res - n; } static long interio(Fsdev *mp, int isread, void *a, long n, vlong off) { int i; Chan* mc; long l, wl, wsz; vlong woff, blk, mblk; long boff, res; blk = off / Blksize; boff = off % Blksize; wsz = Blksize - boff; res = n; while(n > 0){ i = blk % mp->ndevs; mc = mp->idev[i]; mblk = blk / mp->ndevs; woff = mblk * Blksize + boff; if (n > wsz) l = wsz; else l = n; if (isread) wl = devtab[mc->type]->read(mc, a, l, woff); else wl = devtab[mc->type]->write(mc, a, l, woff); if (wl != l || l == 0) error(Eio); a = (char*)a + l; n -= l; blk++; boff = 0; wsz = Blksize; } return res; } static long mread(Chan *c, void *a, long n, vlong off) { int i; Fsdev *mp; Chan *mc; long l; long res; if (c->qid.type & QTDIR) return devdirread(c, a, n, 0, 0, mgen); if (c->qid.path == Qctl) return readstr((long)off, a, n, confstr + strlen(Cfgstr)); i = c->qid.path - Qfirst; mp = path2dev(i, 1); if (off >= mp->size) return 0; if (off + n > mp->size) n = mp->size - off; if (n == 0) return 0; res = -1; switch(mp->type){ case Fmirror: for (i = 0; i < mp->ndevs; i++){ mc = mp->idev[i]; if (waserror()){ // if a read fails we let the user know and try // another device. print("#k: mread: (%llx %d): %s\n", c->qid.path, i, up->env->errstr); continue; } l = devtab[mc->type]->read(mc, a, n, off); poperror(); if (l >=0){ res = l; break; } } if (i == mp->ndevs) error(Eio); break; case Fcat: res = catio(mp, 1, a, n, off); break; case Finter: res = interio(mp, 1, a, n, off); break; case Fpart: off += mp->start; mc = mp->idev[0]; res = devtab[mc->type]->read(mc, a, n, off); break; } return res; } static long mwrite(Chan *c, void *a, long n, vlong off) { Fsdev *mp; long l, res; int i; Chan *mc; if (c->qid.type & QTDIR) error(Eperm); if (c->qid.path == Qctl){ mconfig(a, n); return n; } mp = path2dev(c->qid.path - Qfirst, 1); if (off >= mp->size) return 0; if (off + n > mp->size) n = mp->size - off; if (n == 0) return 0; res = n; switch(mp->type){ case Fmirror: for (i = mp->ndevs-1; i >=0; i--){ mc = mp->idev[i]; l = devtab[mc->type]->write(mc, a, n, off); if (l < res) res = l; } break; case Fcat: res = catio(mp, 0, a, n, off); break; case Finter: res = interio(mp, 0, a, n, off); break; case Fpart: mc = mp->idev[0]; off += mp->start; l = devtab[mc->type]->write(mc, a, n, off); if (l < res) res = l; break; } return res; } Dev dsdevtab = { 'k', "ds", devreset, devinit, devshutdown, mattach, mwalk, mstat, mopen, devcreate, mclose, mread, devbread, mwrite, devbwrite, devremove, devwstat, };