ovl: handle idmappings in ovl_xattr_{g,s}et()
When retrieving xattrs from the upper or lower layers take the relevant
mount's idmapping into account. We rely on the previously introduced
ovl_i_path_real() helper to retrieve the relevant path. This is needed
to support idmapped base layers with overlay.
Cc: <linux-unionfs@vger.kernel.org>
Tested-by: Giuseppe Scrivano <gscrivan@redhat.com>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c
index 0b09e62..a3fcb61 100644
--- a/fs/overlayfs/inode.c
+++ b/fs/overlayfs/inode.c
@@ -349,6 +349,7 @@
struct ovl_fs *ofs = OVL_FS(dentry->d_sb);
struct dentry *upperdentry = ovl_i_dentry_upper(inode);
struct dentry *realdentry = upperdentry ?: ovl_dentry_lower(dentry);
+ struct path realpath;
const struct cred *old_cred;
err = ovl_want_write(dentry);
@@ -356,8 +357,9 @@
goto out;
if (!value && !upperdentry) {
+ ovl_path_lower(dentry, &realpath);
old_cred = ovl_override_creds(dentry->d_sb);
- err = vfs_getxattr(&init_user_ns, realdentry, name, NULL, 0);
+ err = vfs_getxattr(mnt_user_ns(realpath.mnt), realdentry, name, NULL, 0);
revert_creds(old_cred);
if (err < 0)
goto out_drop_write;
@@ -395,11 +397,11 @@
{
ssize_t res;
const struct cred *old_cred;
- struct dentry *realdentry =
- ovl_i_dentry_upper(inode) ?: ovl_dentry_lower(dentry);
+ struct path realpath;
+ ovl_i_path_real(inode, &realpath);
old_cred = ovl_override_creds(dentry->d_sb);
- res = vfs_getxattr(&init_user_ns, realdentry, name, value, size);
+ res = vfs_getxattr(mnt_user_ns(realpath.mnt), realpath.dentry, name, value, size);
revert_creds(old_cred);
return res;
}
