On 2021/7/19 下午5:57, Anand Jain wrote:

On 18/07/2021 20:54, Qu Wenruo wrote:

quoted

Make sure btrfs check can detect such problem.

Right now we have no way to fix it yet.

Signed-off-by: Qu Wenruo <redacted>

Test case runs fine. Do you use any tool to create the crafted image?

As usual, just hard coded btrfs-corrupt-block to call btrfs_add_link()
for a directory.

Thus there isn't really a good tool to craft such image.

Thanks,
Qu

Reviewed-by: Anand Jain <redacted>

Thanks, Anand

quoted

---
  .../049-dir-hard-link/default.img.xz          | Bin 0 -> 1712 bytes
  tests/fsck-tests/049-dir-hard-link/test.sh    |  19 ++++++++++++++++++
  2 files changed, 19 insertions(+)
  create mode 100644 tests/fsck-tests/049-dir-hard-link/default.img.xz
  create mode 100755 tests/fsck-tests/049-dir-hard-link/test.sh

diff --git a/tests/fsck-tests/049-dir-hard-link/default.img.xz

b/tests/fsck-tests/049-dir-hard-link/default.img.xz
new file mode 100644
index
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diff --git a/tests/fsck-tests/049-dir-hard-link/test.sh

b/tests/fsck-tests/049-dir-hard-link/test.sh
new file mode 100755
index 000000000000..992ad638bd47

--- /dev/null
+++ b/tests/fsck-tests/049-dir-hard-link/test.sh

@@ -0,0 +1,19 @@
+#!/bin/bash
+#
+# Verify that check can detect overlapped dir with 2 links
+#
+# There is a report that btrfs-check doesn't report dir with 2 links as
+# error, and only get caught by tree-checker.
+#
+# Make sure btrfs check can at least detect such error
+
+source "$TEST_TOP/common"
+
+check_prereq btrfs
+
+check_image() {
+    run_mustfail "dir with 2 links not detected" \
+        "$TOP/btrfs" check "$1"
+}
+
+check_all_images