Re: [Qemu-devel] [PATCH v6 2/4] 9p: Added virtfs option 'multidevs=remap|forbid|warn'

[Christian Schoenebeck via Qemu-devel <qemu-devel@nongnu.org>]

On Freitag, 30. August 2019 14:22:38 CEST Greg Kurz wrote:
> Some more comments below.
[snip]
> > diff --git a/hw/9pfs/9p.c b/hw/9pfs/9p.c
> > index 8cc65c2c67..c96ea51116 100644
> > --- a/hw/9pfs/9p.c
> > +++ b/hw/9pfs/9p.c
> > @@ -25,6 +25,7 @@
> > 
> >  #include "trace.h"
> >  #include "migration/blocker.h"
> >  #include "sysemu/qtest.h"
[snip]
> > @@ -3672,8 +3807,13 @@ int v9fs_device_realize_common(V9fsState *s, const
> > V9fsTransport *t,> 
> >          goto out;
> >      
> >      }
> > 
> > +    s->root_ino = stat.st_ino;
> 
> This isn't used anywhere. It looks like a leftover of the readdir fix
> in v5.

Yes, both correct. I intentionally left it though, since I found it a natural 
complement always capturing the root inode along to the root device.

> >      s->dev_id = stat.st_dev;
> > 
> > +    /* QID path hash table. 1 entry ought to be enough for anybody ;) */
> > +    qht_init(&s->qpp_table, qpp_lookup_func, 1, QHT_MODE_AUTO_RESIZE);
> > +    s->qp_prefix_next = 1; /* reserve 0 to detect overflow */
> > +
> > 
> >      s->ctx.fst = &fse->fst;
> >      fsdev_throttle_init(s->ctx.fst);
> > 
> > @@ -3687,6 +3827,7 @@ out:
> >          }
> >          g_free(s->tag);
> >          g_free(s->ctx.fs_root);
> > 
> > +        qpp_table_destroy(&s->qpp_table);
> > 
> >          v9fs_path_free(&path);
> >      
> >      }
> >      return rc;
> > 
> > @@ -3699,6 +3840,7 @@ void v9fs_device_unrealize_common(V9fsState *s,
> > Error **errp)> 
> >      }
> >      fsdev_throttle_cleanup(s->ctx.fst);
> >      g_free(s->tag);
> > 
> > +    qpp_table_destroy(&s->qpp_table);
> > 
> >      g_free(s->ctx.fs_root);
> >  
> >  }
> > 
> > diff --git a/hw/9pfs/9p.h b/hw/9pfs/9p.h
> > index 5e316178d5..a283b0193e 100644
> > --- a/hw/9pfs/9p.h
> > +++ b/hw/9pfs/9p.h
> > @@ -8,6 +8,7 @@
> > 
> >  #include "fsdev/9p-iov-marshal.h"
> >  #include "qemu/thread.h"
> >  #include "qemu/coroutine.h"
> > 
> > +#include "qemu/qht.h"
> > 
> >  enum {
> >  
> >      P9_TLERROR = 6,
> > 
> > @@ -235,6 +236,15 @@ struct V9fsFidState
> > 
> >      V9fsFidState *rclm_lst;
> >  
> >  };
> > 
> > +#define QPATH_INO_MASK        ((1ULL << 48) - 1)
> > +
> > +/* QID path prefix entry, see stat_to_qid */
> > +typedef struct {
> > +    dev_t dev;
> > +    uint16_t ino_prefix;
> > +    uint16_t qp_prefix;
> > +} QppEntry;
> > +
> > 
> >  struct V9fsState
> >  {
> >  
> >      QLIST_HEAD(, V9fsPDU) free_list;
> > 
> > @@ -256,7 +266,10 @@ struct V9fsState
> > 
> >      Error *migration_blocker;
> >      V9fsConf fsconf;
> >      V9fsQID root_qid;
> > 
> > +    ino_t root_ino;
> 
> Thinking again, I'm wondering if root_ino and dev_id could be used
> instead of root_qid in v9fs_walk()... Would you have a look at that
> if you decide to fix the readdir issue ?

I keep it in mind when looking at the postponed readdir() issue again.

> >      dev_t dev_id;
> > 
> > +    struct qht qpp_table;
> > +    uint16_t qp_prefix_next;
> > 
> >  };
> >  
> >  /* 9p2000.L open flags */
> >