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authorjeff <jeff@FreeBSD.org>2006-03-31 03:52:24 +0000
committerjeff <jeff@FreeBSD.org>2006-03-31 03:52:24 +0000
commitd018a9a82031a9c4b99602056e747592e74b6b80 (patch)
tree1dfd6abf75b0ca4f6116ac125e0ee25c0e65269e
parent1a43943ef60bbb86e45d755c6d1055f7513530a5 (diff)
downloadFreeBSD-src-d018a9a82031a9c4b99602056e747592e74b6b80.zip
FreeBSD-src-d018a9a82031a9c4b99602056e747592e74b6b80.tar.gz
- GETWRITEMOUNT now returns a referenced mountpoint to prevent its
identity from changing. This is possible now that mounts are not freed. Discussed with: tegge Tested by: kris Sponsored by: Isilon Systems, Inc.
-rw-r--r--sys/kern/vfs_default.c16
1 files changed, 15 insertions, 1 deletions
diff --git a/sys/kern/vfs_default.c b/sys/kern/vfs_default.c
index 5f43685..bf33115 100644
--- a/sys/kern/vfs_default.c
+++ b/sys/kern/vfs_default.c
@@ -343,8 +343,22 @@ vop_stdgetwritemount(ap)
struct mount **a_mpp;
} */ *ap;
{
+ struct mount *mp;
- *(ap->a_mpp) = ap->a_vp->v_mount;
+ /*
+ * XXX Since this is called unlocked we may be recycled while
+ * attempting to ref the mount. If this is the case or mountpoint
+ * will be set to NULL. We only have to prevent this call from
+ * returning with a ref to an incorrect mountpoint. It is not
+ * harmful to return with a ref to our previous mountpoint.
+ */
+ mp = ap->a_vp->v_mount;
+ vfs_ref(mp);
+ if (mp != ap->a_vp->v_mount) {
+ vfs_rel(mp);
+ mp = NULL;
+ }
+ *(ap->a_mpp) = mp;
return (0);
}
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