[PATCH 2/3] vfs: force reval on dentry of bind mounted files on FS_REVAL_DOT filesystems

Jeff Layton
2009-11-23T17:41:32Z

In the case of a bind mounted file, the path walking code will assume
that the cached dentry that was bind mounted is valid. This is a problem
problem for NFSv4 in a way that's similar to LAST_BIND symlinks.

Fix this by revalidating the dentry if LOOKUP_OPEN is set and
__follow_mount returns true.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
---
fs/namei.c | 9 +++++++--
1 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/fs/namei.c b/fs/namei.c
index 2c10519..738b257 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -838,6 +838,7 @@ static int do_lookup(struct nameidata *nd, struct qstr *name,
{
struct vfsmount *mnt = nd->path.mnt;
struct dentry *dentry = __d_lookup(nd->path.dentry, name);
+ int error = 0;

if (!dentry)
goto need_lookup;
@@ -846,8 +847,9 @@ static int do_lookup(struct nameidata *nd, struct qstr *name,
done:
path->mnt = mnt;
path->dentry = dentry;
- __follow_mount(path);
- return 0;
+ if (__follow_mount(path))
+ error = force_reval_path(path, nd);
+ return error;

need_lookup:
dentry = real_lookup(nd->path.dentry, name, nd);
@@ -1835,6 +1837,9 @@ do_last:
error = -ELOOP;
if (flag & O_NOFOLLOW)
goto exit_dput;
+ error = force_reval_path(&path, &nd);
+ if (error)
+ goto exit;
}

error = -ENOENT;
--
1.5.5.6