ovl: generalize ovl_verify_origin() and helpers

Remove the "origin" language from the functions that handle set, get
and verify of "origin" xattr and pass the xattr name as an argument.

The same helpers are going to be used for NFS export to get, get and
verify the "upper" xattr for directory index entries.

ovl_verify_origin() is now a helper used only to verify non upper
file handle stored in "origin" xattr of upper inode.

The upper root dir file handle is still stored in "origin" xattr on
the index dir for backward compatibility. This is going to be changed
by the patch that adds directory index entries support.

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

1 files changed, 22 insertions, 20 deletions

diff --git a/fs/overlayfs/namei.c b/fs/overlayfs/namei.c
index 27f25a61f6e4..11e164cb2593 100644
--- a/fs/overlayfs/namei.c
+++ b/fs/overlayfs/namei.c
@@ -114,12 +114,12 @@ static int ovl_check_fh_len(struct ovl_fh *fh, int fh_len)
         return 0;
 }
 
-static struct ovl_fh *ovl_get_origin_fh(struct dentry *dentry)
+static struct ovl_fh *ovl_get_fh(struct dentry *dentry, const char *name)
 {
         int res, err;
         struct ovl_fh *fh = NULL;
 
-        res = vfs_getxattr(dentry, OVL_XATTR_ORIGIN, NULL, 0);
+        res = vfs_getxattr(dentry, name, NULL, 0);
         if (res < 0) {
                 if (res == -ENODATA || res == -EOPNOTSUPP)
                         return NULL;
@@ -133,7 +133,7 @@ static struct ovl_fh *ovl_get_origin_fh(struct dentry *dentry)
         if (!fh)
                 return ERR_PTR(-ENOMEM);
 
-        res = vfs_getxattr(dentry, OVL_XATTR_ORIGIN, fh, res);
+        res = vfs_getxattr(dentry, name, fh, res);
         if (res < 0)
                 goto fail;
 
@@ -337,7 +337,7 @@ invalid:
 static int ovl_check_origin(struct ovl_fs *ofs, struct dentry *upperdentry,
                             struct ovl_path **stackp, unsigned int *ctrp)
 {
-        struct ovl_fh *fh = ovl_get_origin_fh(upperdentry);
+        struct ovl_fh *fh = ovl_get_fh(upperdentry, OVL_XATTR_ORIGIN);
         int err;
 
         if (IS_ERR_OR_NULL(fh))
@@ -360,12 +360,13 @@ static int ovl_check_origin(struct ovl_fs *ofs, struct dentry *upperdentry,
 }
 
 /*
- * Verify that @fh matches the origin file handle stored in OVL_XATTR_ORIGIN.
+ * Verify that @fh matches the file handle stored in xattr @name.
  * Return 0 on match, -ESTALE on mismatch, < 0 on error.
  */
-static int ovl_verify_origin_fh(struct dentry *dentry, const struct ovl_fh *fh)
+static int ovl_verify_fh(struct dentry *dentry, const char *name,
+                         const struct ovl_fh *fh)
 {
-        struct ovl_fh *ofh = ovl_get_origin_fh(dentry);
+        struct ovl_fh *ofh = ovl_get_fh(dentry, name);
         int err = 0;
 
         if (!ofh)
@@ -382,28 +383,28 @@ static int ovl_verify_origin_fh(struct dentry *dentry, const struct ovl_fh *fh)
 }
 
 /*
- * Verify that an inode matches the origin file handle stored in upper inode.
+ * Verify that @real dentry matches the file handle stored in xattr @name.
  *
- * If @set is true and there is no stored file handle, encode and store origin
- * file handle in OVL_XATTR_ORIGIN.
+ * If @set is true and there is no stored file handle, encode @real and store
+ * file handle in xattr @name.
  *
- * Return 0 on match, -ESTALE on mismatch, < 0 on error.
+ * Return 0 on match, -ESTALE on mismatch, -ENODATA on no xattr, < 0 on error.
  */
-int ovl_verify_origin(struct dentry *dentry, struct dentry *origin,
-                      bool is_upper, bool set)
+int ovl_verify_set_fh(struct dentry *dentry, const char *name,
+                      struct dentry *real, bool is_upper, bool set)
 {
         struct inode *inode;
         struct ovl_fh *fh;
         int err;
 
-        fh = ovl_encode_fh(origin, is_upper);
+        fh = ovl_encode_fh(real, is_upper);
         err = PTR_ERR(fh);
         if (IS_ERR(fh))
                 goto fail;
 
-        err = ovl_verify_origin_fh(dentry, fh);
+        err = ovl_verify_fh(dentry, name, fh);
         if (set && err == -ENODATA)
-                err = ovl_do_setxattr(dentry, OVL_XATTR_ORIGIN, fh, fh->len, 0);
+                err = ovl_do_setxattr(dentry, name, fh, fh->len, 0);
         if (err)
                 goto fail;
 
@@ -412,9 +413,10 @@ out:
         return err;
 
 fail:
-        inode = d_inode(origin);
-        pr_warn_ratelimited("overlayfs: failed to verify origin (%pd2, ino=%lu, err=%i)\n",
-                            origin, inode ? inode->i_ino : 0, err);
+        inode = d_inode(real);
+        pr_warn_ratelimited("overlayfs: failed to verify %s (%pd2, ino=%lu, err=%i)\n",
+                            is_upper ? "upper" : "origin", real,
+                            inode ? inode->i_ino : 0, err);
         goto out;
 }
 
@@ -466,7 +468,7 @@ int ovl_verify_index(struct ovl_fs *ofs, struct dentry *index)
         if (err)
                 goto fail;
 
-        err = ovl_verify_origin_fh(index, fh);
+        err = ovl_verify_fh(index, OVL_XATTR_ORIGIN, fh);
         if (err)
                 goto fail;