ovl: factor out ovl_get_index_fh() helper

The helper is needed to lookup an index by file handle for NFS export.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>

diff --git a/fs/overlayfs/namei.c b/fs/overlayfs/namei.c
index 111a64f..49984c9 100644 (file)
--- a/fs/overlayfs/namei.c
+++ b/fs/overlayfs/namei.c
@@ -585,6 +585,21 @@ orphan:
        goto out;
 }
 
+static int ovl_get_index_name_fh(struct ovl_fh *fh, struct qstr *name)
+{
+       char *n, *s;
+
+       n = kzalloc(fh->len * 2, GFP_KERNEL);
+       if (!n)
+               return -ENOMEM;
+
+       s  = bin2hex(n, fh, fh->len);
+       *name = (struct qstr) QSTR_INIT(n, s - n);
+
+       return 0;
+
+}
+
 /*
  * Lookup in indexdir for the index entry of a lower real inode or a copy up
  * origin inode. The index entry name is the hex representation of the lower
@@ -602,25 +617,49 @@ orphan:
  */
 int ovl_get_index_name(struct dentry *origin, struct qstr *name)
 {
-       int err;
        struct ovl_fh *fh;
-       char *n, *s;
+       int err;
 
        fh = ovl_encode_fh(origin, false);
        if (IS_ERR(fh))
                return PTR_ERR(fh);
 
-       err = -ENOMEM;
-       n = kzalloc(fh->len * 2, GFP_KERNEL);
-       if (n) {
-               s  = bin2hex(n, fh, fh->len);
-               *name = (struct qstr) QSTR_INIT(n, s - n);
-               err = 0;
-       }
-       kfree(fh);
+       err = ovl_get_index_name_fh(fh, name);
 
+       kfree(fh);
        return err;
+}
+
+/* Lookup index by file handle for NFS export */
+struct dentry *ovl_get_index_fh(struct ovl_fs *ofs, struct ovl_fh *fh)
+{
+       struct dentry *index;
+       struct qstr name;
+       int err;
+
+       err = ovl_get_index_name_fh(fh, &name);
+       if (err)
+               return ERR_PTR(err);
+
+       index = lookup_one_len_unlocked(name.name, ofs->indexdir, name.len);
+       kfree(name.name);
+       if (IS_ERR(index)) {
+               if (PTR_ERR(index) == -ENOENT)
+                       index = NULL;
+               return index;
+       }
 
+       if (d_is_negative(index))
+               err = 0;
+       else if (ovl_is_whiteout(index))
+               err = -ESTALE;
+       else if (ovl_dentry_weird(index))
+               err = -EIO;
+       else
+               return index;
+
+       dput(index);
+       return ERR_PTR(err);
 }
 
 static struct dentry *ovl_lookup_index(struct dentry *dentry,

diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h
index 8f4313c..4e784f6 100644 (file)
--- a/fs/overlayfs/overlayfs.h
+++ b/fs/overlayfs/overlayfs.h
@@ -257,6 +257,7 @@ int ovl_verify_set_fh(struct dentry *dentry, const char *name,
                      struct dentry *real, bool is_upper, bool set);
 int ovl_verify_index(struct ovl_fs *ofs, struct dentry *index);
 int ovl_get_index_name(struct dentry *origin, struct qstr *name);
+struct dentry *ovl_get_index_fh(struct ovl_fs *ofs, struct ovl_fh *fh);
 int ovl_path_next(int idx, struct dentry *dentry, struct path *path);
 struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
                          unsigned int flags);