[PATCH v3] xfsrestore: suggest -x rather than assert for false roots

[Donald Douwsma <ddouwsma@redhat.com>]

If we're going to have a fix for false root problems its a good idea to
let people know that there's a way to recover, error out with a useful
message that mentions the `-x` option rather than just assert.

Before

  xfsrestore: searching media for directory dump
  xfsrestore: reading directories
  xfsrestore: tree.c:757: tree_begindir: Assertion `ino != persp->p_rootino || hardh == persp->p_rooth' failed.
  Aborted

After

  xfsrestore: ERROR: tree.c:791: tree_begindir: Assertion `ino != persp->p_rootino || hardh == persp->p_rooth` failed.
  xfsrestore: ERROR: False root detected. Recovery may be possible using the `-x` option
  Aborted

Fixes: d7cba7410710 ("xfsrestore: fix rootdir due to xfsdump bulkstat misuse")
Signed-off-by: Donald Douwsma <ddouwsma@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>

---
Changes for v2
- Use xfsprogs style for conditional
- Remove trailing white-space
- Place printf format all on one line for grepability
- use __func__ instead of gcc specific __FUNCTION__
Changes for v3
- Fix indentation of if statement
---
 restore/tree.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/restore/tree.c b/restore/tree.c
index bfa07fe..6f3180f 100644
--- a/restore/tree.c
+++ b/restore/tree.c
@@ -783,8 +783,15 @@ tree_begindir(filehdr_t *fhdrp, dah_t *dahp)
 	/* lookup head of hardlink list
 	 */
 	hardh = link_hardh(ino, gen);
-	if (need_fixrootdir == BOOL_FALSE)
-		assert(ino != persp->p_rootino || hardh == persp->p_rooth);
+	if (need_fixrootdir == BOOL_FALSE &&
+	    !(ino != persp->p_rootino || hardh == persp->p_rooth)) {
+		mlog(MLOG_ERROR | MLOG_TREE,
+"%s:%d: %s: Assertion `ino != persp->p_rootino || hardh == persp->p_rooth` failed.\n",
+			__FILE__, __LINE__, __func__);
+		mlog(MLOG_ERROR | MLOG_TREE, _(
+"False root detected. Recovery may be possible using the `-x` option\n"));
+		return NH_NULL;
+	}
 
 	/* already present
 	 */
-- 
2.39.3