qemu-devel
[Top][All Lists]
Advanced
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Qemu-devel] [PATCH 2/6] hw/9pfs: Don't free fid in clunk

From: Venkateswararao Jujjuri
Subject: Re: [Qemu-devel] [PATCH 2/6] hw/9pfs: Don't free fid in clunk
Date: Thu, 09 Jun 2011 17:27:00 -0700
User-agent: Mozilla/5.0 (X11; U; Linux i686 (x86_64); en-US; rv:1.9.2.17) Gecko/20110414 Thunderbird/3.1.10 
On 06/06/2011 10:16 AM, Aneesh Kumar K.V wrote:

On interrupted syscall on client we can end up having fid
being acted upon by glib pool but still get a clunk request on that


Couple of comments below.

- JV


Signed-off-by: Aneesh Kumar K.V<address@hidden>
---
  hw/9pfs/virtio-9p.c |  139 +++++++++++++++++++++++++++-----------------------
  hw/9pfs/virtio-9p.h |    7 +--
  2 files changed, 76 insertions(+), 70 deletions(-)

diff --git a/hw/9pfs/virtio-9p.c b/hw/9pfs/virtio-9p.c
index 03d8664..f3127a5 100644
--- a/hw/9pfs/virtio-9p.c
+++ b/hw/9pfs/virtio-9p.c
@@ -237,12 +237,11 @@ static V9fsFidState *get_fid(V9fsState *s, int32_t fid)
      V9fsFidState *f;

      for (f = s->fid_list; f; f = f->next) {
-        if (f->fid == fid) {
+        if (f->fid == fid&&  !f->clunked) {
              f->ref++;
              return f;
          }
      }
-
      return NULL;
  }

@@ -250,12 +249,12 @@ static V9fsFidState *alloc_fid(V9fsState *s, int32_t fid)
  {
      V9fsFidState *f;

-    f = get_fid(s, fid);
-    if (f) {
-        f->ref--;
-        return NULL;
+    for (f = s->fid_list; f; f = f->next) {
+        /* If fid is already there return NULL */
+        if (f->fid == fid&&  !f->clunked) {
+            return NULL;
+        }
      }
-
      f = qemu_mallocz(sizeof(V9fsFidState));

Memory leak if we find a cluncked fid here?
More than that how do you handle this?

      f->fid = fid;
      f->fid_type = P9_FID_NONE;
@@ -300,9 +299,33 @@ free_value:
      return retval;
  }

-static int free_fid(V9fsState *s, int32_t fid)
+static int release_fid(V9fsState *s, V9fsFidState *fidp)
  {
      int retval = 0;
+
+    if (fidp->fid_type == P9_FID_FILE) {
+        retval = v9fs_co_close(s, fidp);
+    } else if (fidp->fid_type == P9_FID_DIR) {
+        retval = v9fs_co_closedir(s, fidp);
+    } else if (fidp->fid_type == P9_FID_XATTR) {
+        retval = v9fs_xattr_fid_clunk(s, fidp);
+    }
+    v9fs_string_free(&fidp->path);
+    qemu_free(fidp);
+    return retval;
+}
+
+static void put_fid(V9fsState *s, V9fsFidState *fidp)
+{
+    BUG_ON(!fidp->ref);
+    fidp->ref--;
+    if (!fidp->ref&&  fidp->clunked) {
+        release_fid(s, fidp);
+    }
+}
+
+static int free_fid(V9fsState *s, int32_t fid)

With the changed semantics; I would suggest you to swap the names of
release_fid() and free_fid()

Or even better
free_fid() -> clunk_fid()
release_fid() -> free_fid()

+{
      V9fsFidState **fidpp, *fidp;

      for (fidpp =&s->fid_list; *fidpp; fidpp =&(*fidpp)->next) {
@@ -314,20 +337,10 @@ static int free_fid(V9fsState *s, int32_t fid)
      if (*fidpp == NULL) {
          return -ENOENT;
      }
-
      fidp = *fidpp;
      *fidpp = fidp->next;
-
-    if (fidp->fid_type == P9_FID_FILE) {
-        retval = v9fs_co_close(s, fidp);
-    } else if (fidp->fid_type == P9_FID_DIR) {
-        retval = v9fs_co_closedir(s, fidp);
-    } else if (fidp->fid_type == P9_FID_XATTR) {
-        retval = v9fs_xattr_fid_clunk(s, fidp);
-    }
-    v9fs_string_free(&fidp->path);
-    qemu_free(fidp);
-    return retval;
+    fidp->clunked = 1;
+    return 0;
  }

  #define P9_QID_TYPE_DIR         0x80
@@ -1022,14 +1035,13 @@ static void v9fs_attach(void *opaque)
      err = fid_to_qid(s, fidp,&qid);
      if (err<  0) {
          err = -EINVAL;
-        put_fid(fidp);
          free_fid(s, fid);
-        goto out_nofid;
+        goto out;
      }
      offset += pdu_marshal(pdu, offset, "Q",&qid);
      err = offset;
-    put_fid(fidp);
-
+out:
+    put_fid(s, fidp);
  out_nofid:
      complete_pdu(s, pdu, err);
      v9fs_string_free(&uname);
@@ -1066,7 +1078,7 @@ static void v9fs_stat(void *opaque)
      err = offset;
      v9fs_stat_free(&v9stat);
  out:
-    put_fid(fidp);
+    put_fid(s, fidp);
  out_nofid:
      complete_pdu(s, pdu, err);
  }
@@ -1102,7 +1114,7 @@ static void v9fs_getattr(void *opaque)
      retval = offset;
      retval += pdu_marshal(pdu, offset, "A",&v9stat_dotl);
  out:
-    put_fid(fidp);
+    put_fid(s, fidp);
  out_nofid:
      complete_pdu(s, pdu, retval);
  }
@@ -1196,7 +1208,7 @@ static void v9fs_setattr(void *opaque)
      }
      err = offset;
  out:
-    put_fid(fidp);
+    put_fid(s, fidp);
  out_nofid:
      complete_pdu(s, pdu, err);
  }
@@ -1279,9 +1291,7 @@ static void v9fs_walk(void *opaque)
              v9fs_string_copy(&newfidp->path,&path);
              err = v9fs_co_lstat(s,&newfidp->path,&stbuf);
              if (err<  0) {
-                put_fid(newfidp);
                  free_fid(s, newfidp->fid);
-                newfidp = NULL;
                  v9fs_string_free(&path);
                  goto out;
              }
@@ -1291,9 +1301,9 @@ static void v9fs_walk(void *opaque)
      }
      err = v9fs_walk_marshal(pdu, nwnames, qids);
  out:
-    put_fid(fidp);
+    put_fid(s, fidp);
      if (newfidp) {
-        put_fid(newfidp);
+        put_fid(s, newfidp);
      }
  out_nofid:
      complete_pdu(s, pdu, err);
@@ -1383,7 +1393,7 @@ static void v9fs_open(void *opaque)
          err = offset;
      }
  out:
-    put_fid(fidp);
+    put_fid(s, fidp);
  out_nofid:
      complete_pdu(s, pdu, err);
  }
@@ -1437,7 +1447,7 @@ static void v9fs_lcreate(void *opaque)
      offset += pdu_marshal(pdu, offset, "Qd",&qid, iounit);
      err = offset;
  out:
-    put_fid(fidp);
+    put_fid(pdu->s, fidp);
  out_nofid:
      complete_pdu(pdu->s, pdu, err);
      v9fs_string_free(&name);
@@ -1465,7 +1475,7 @@ static void v9fs_fsync(void *opaque)
          err = offset;
      }
  out:
-    put_fid(fidp);
+    put_fid(s, fidp);
      complete_pdu(s, pdu, err);
  }

@@ -1474,16 +1484,25 @@ static void v9fs_clunk(void *opaque)
      int err;
      int32_t fid;
      size_t offset = 7;
+    V9fsFidState *fidp;
      V9fsPDU *pdu = opaque;
      V9fsState *s = pdu->s;

      pdu_unmarshal(pdu, offset, "d",&fid);
-    err = free_fid(s, fid);
+
+    fidp = get_fid(s, fid);
+    if (fidp == NULL) {
+        err = -ENOENT;
+        goto out_nofid;
+    }
+    err = free_fid(s, fidp->fid);
      if (err<  0) {
          goto out;
      }
      err = offset;
  out:
+    put_fid(s, fidp);
+out_nofid:
      complete_pdu(s, pdu, err);
  }

@@ -1638,7 +1657,7 @@ static void v9fs_read(void *opaque)
          err = -EINVAL;
      }
  out:
-    put_fid(fidp);
+    put_fid(s, fidp);
  out_nofid:
      complete_pdu(s, pdu, err);
  }
@@ -1747,7 +1766,7 @@ static void v9fs_readdir(void *opaque)
      retval += pdu_marshal(pdu, offset, "d", count);
      retval += count;
  out:
-    put_fid(fidp);
+    put_fid(s, fidp);
  out_nofid:
      complete_pdu(s, pdu, retval);
  }
@@ -1857,7 +1876,7 @@ static void v9fs_write(void *opaque)
      offset += pdu_marshal(pdu, offset, "d", total);
      err = offset;
  out:
-    put_fid(fidp);
+    put_fid(s, fidp);
  out_nofid:
      complete_pdu(s, pdu, err);
  }
@@ -1923,10 +1942,10 @@ static void v9fs_create(void *opaque)
          }
          err = v9fs_co_link(pdu->s,&nfidp->path,&fullname);
          if (err<  0) {
-            put_fid(nfidp);
+            put_fid(pdu->s, nfidp);
              goto out;
          }
-        put_fid(nfidp);
+        put_fid(pdu->s, nfidp);
      } else if (perm&  P9_STAT_MODE_DEVICE) {
          char ctype;
          uint32_t major, minor;
@@ -1990,7 +2009,7 @@ static void v9fs_create(void *opaque)
      err = offset;

  out:
-    put_fid(fidp);
+    put_fid(pdu->s, fidp);
  out_nofid:
     complete_pdu(pdu->s, pdu, err);
     v9fs_string_free(&name);
@@ -2035,7 +2054,7 @@ static void v9fs_symlink(void *opaque)
      offset += pdu_marshal(pdu, offset, "Q",&qid);
      err = offset;
  out:
-    put_fid(dfidp);
+    put_fid(pdu->s, dfidp);
  out_nofid:
      complete_pdu(pdu->s, pdu, err);
      v9fs_string_free(&name);
@@ -2086,7 +2105,7 @@ static void v9fs_link(void *opaque)
      v9fs_string_free(&fullname);

  out:
-    put_fid(dfidp);
+    put_fid(s, dfidp);
  out_nofid:
      v9fs_string_free(&name);
      complete_pdu(s, pdu, err);
@@ -2113,8 +2132,8 @@ static void v9fs_remove(void *opaque)
      }

      /* For TREMOVE we need to clunk the fid even on failed remove */
-    put_fid(fidp);
      free_fid(pdu->s, fidp->fid);
+    put_fid(pdu->s, fidp);
  out_nofid:
      complete_pdu(pdu->s, pdu, err);
  }
@@ -2185,7 +2204,7 @@ static int v9fs_complete_rename(V9fsState *s, 
V9fsFidState *fidp,
      }
  out:
      if (dirfidp) {
-        put_fid(dirfidp);
+        put_fid(s, dirfidp);
      }
  out_nofid:
      return err;
@@ -2216,7 +2235,7 @@ static void v9fs_rename(void *opaque)
          err = offset;
      }
  out:
-    put_fid(fidp);
+    put_fid(s, fidp);
  out_nofid:
      complete_pdu(s, pdu, err);
      v9fs_string_free(&name);
@@ -2305,7 +2324,7 @@ static void v9fs_wstat(void *opaque)
      }
      err = offset;
  out:
-    put_fid(fidp);
+    put_fid(s, fidp);
  out_nofid:
      v9fs_stat_free(&v9stat);
      complete_pdu(s, pdu, err);
@@ -2379,7 +2398,7 @@ static void v9fs_statfs(void *opaque)
      retval = offset;
      retval += v9fs_fill_statfs(s, pdu,&stbuf);
  out:
-    put_fid(fidp);
+    put_fid(s, fidp);
  out_nofid:
      complete_pdu(s, pdu, retval);
      return;
@@ -2425,7 +2444,7 @@ static void v9fs_mknod(void *opaque)
      err = offset;
      err += pdu_marshal(pdu, offset, "Q",&qid);
  out:
-    put_fid(fidp);
+    put_fid(s, fidp);
  out_nofid:
      complete_pdu(s, pdu, err);
      v9fs_string_free(&fullname);
@@ -2473,7 +2492,7 @@ static void v9fs_lock(void *opaque)
      }
      status = P9_LOCK_SUCCESS;
  out:
-    put_fid(fidp);
+    put_fid(s, fidp);
  out_nofid:
      err = offset;
      err += pdu_marshal(pdu, offset, "b", status);
@@ -2515,7 +2534,7 @@ static void v9fs_getlock(void *opaque)
                            &glock->client_id);
      err = offset;
  out:
-    put_fid(fidp);
+    put_fid(s, fidp);
  out_nofid:
      complete_pdu(s, pdu, err);
      qemu_free(glock);
@@ -2555,7 +2574,7 @@ static void v9fs_mkdir(void *opaque)
      offset += pdu_marshal(pdu, offset, "Q",&qid);
      err = offset;
  out:
-    put_fid(fidp);
+    put_fid(pdu->s, fidp);
  out_nofid:
      complete_pdu(pdu->s, pdu, err);
      v9fs_string_free(&fullname);
@@ -2593,9 +2612,7 @@ static void v9fs_xattrwalk(void *opaque)
          size = v9fs_co_llistxattr(s,&xattr_fidp->path, NULL, 0);
          if (size<  0) {
              err = size;
-            put_fid(xattr_fidp);
              free_fid(s, xattr_fidp->fid);
-            xattr_fidp = NULL;
              goto out;
          }
          /*
@@ -2610,9 +2627,7 @@ static void v9fs_xattrwalk(void *opaque)
                                       xattr_fidp->fs.xattr.value,
                                       xattr_fidp->fs.xattr.len);
              if (err<  0) {
-                put_fid(xattr_fidp);
                  free_fid(s, xattr_fidp->fid);
-                xattr_fidp = NULL;
                  goto out;
              }
          }
@@ -2627,9 +2642,7 @@ static void v9fs_xattrwalk(void *opaque)
                                   &name, NULL, 0);
          if (size<  0) {
              err = size;
-            put_fid(xattr_fidp);
              free_fid(s, xattr_fidp->fid);
-            xattr_fidp = NULL;
              goto out;
          }
          /*
@@ -2644,9 +2657,7 @@ static void v9fs_xattrwalk(void *opaque)
                                      &name, xattr_fidp->fs.xattr.value,
                                      xattr_fidp->fs.xattr.len);
              if (err<  0) {
-                put_fid(xattr_fidp);
                  free_fid(s, xattr_fidp->fid);
-                xattr_fidp = NULL;
                  goto out;
              }
          }
@@ -2654,9 +2665,9 @@ static void v9fs_xattrwalk(void *opaque)
          err = offset;
      }
  out:
-    put_fid(file_fidp);
+    put_fid(s, file_fidp);
      if (xattr_fidp) {
-        put_fid(xattr_fidp);
+        put_fid(s, xattr_fidp);
      }
  out_nofid:
      complete_pdu(s, pdu, err);
@@ -2698,7 +2709,7 @@ static void v9fs_xattrcreate(void *opaque)
          xattr_fidp->fs.xattr.value = NULL;
      }
      err = offset;
-    put_fid(file_fidp);
+    put_fid(s, file_fidp);
  out_nofid:
      complete_pdu(s, pdu, err);
      v9fs_string_free(&name);
@@ -2729,7 +2740,7 @@ static void v9fs_readlink(void *opaque)
      err = offset;
      v9fs_string_free(&target);
  out:
-    put_fid(fidp);
+    put_fid(pdu->s, fidp);
  out_nofid:
      complete_pdu(pdu->s, pdu, err);
  }
diff --git a/hw/9pfs/virtio-9p.h b/hw/9pfs/virtio-9p.h
index ce93c20..e16e5f4 100644
--- a/hw/9pfs/virtio-9p.h
+++ b/hw/9pfs/virtio-9p.h
@@ -204,6 +204,7 @@ struct V9fsFidState
      } fs;
      uid_t uid;
      int ref;
+    int clunked;
      V9fsFidState *next;
  };

@@ -362,11 +363,5 @@ static inline size_t do_pdu_unpack(void *dst, struct iovec 
*sg, int sg_count,
      return pdu_packunpack(dst, sg, sg_count, offset, size, 0);
  }

-static inline void put_fid(V9fsFidState *fidp)
-{
-    BUG_ON(!fidp->ref);
-    fidp->ref--;
-}
-
  extern void handle_9p_output(VirtIODevice *vdev, VirtQueue *vq);
  #endif
reply via email to
[Prev in Thread] Current Thread [Next in Thread]