[PATCH] generic/423: test stx_size of symlink

[Eric Biggers <ebiggers@kernel.org>]

From: Eric Biggers <ebiggers@google.com>

Update generic/423 to test that the reported size of a symlink is equal
to the length of the symlink target, as required by POSIX and as
documented in various man pages.

When the test_dummy_encryption mount option is enabled, this serves as a
regression test for the bug that will be fixed by the patch series
"fscrypt: report correct st_size for encrypted symlinks"
(https://lkml.kernel.org/r/20210702065350.209646-1-ebiggers@kernel.org).
However, this test is applicable to all filesystems and mount options.

Signed-off-by: Eric Biggers <ebiggers@google.com>
---

In the past, it's been mentioned that existing xfstests shouldn't be
updated to test new things
(https://lkml.kernel.org/r/20170315093942.GN14226@eguan.usersys.redhat.com).
I personally think this is a dumb policy and that we should make
improvements like this that belong in the existing tests.  But if it's
really preferred I could instead add a new test script just for this...

 tests/generic/423 | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/tests/generic/423 b/tests/generic/423
index 3de2f30c..69c1c3bc 100755
--- a/tests/generic/423
+++ b/tests/generic/423
@@ -110,13 +110,15 @@ check_stat $TEST_DIR/$seq-file \
 	   stx_nlink=1
 
 echo "Test statx on a symlink"
-ln -s $TEST_DIR/$seq-nowhere $TEST_DIR/$seq-symlink
+target=$TEST_DIR/$seq-nowhere
+ln -s $target $TEST_DIR/$seq-symlink
 check_stat $TEST_DIR/$seq-symlink \
 	   ts_order \
 	   ref=$TEST_DIR/$seq-file \
 	   ts=B,b \
 	   ts=M,m \
 	   stx_type=sym \
+	   stx_size=${#target} \
 	   stx_rdev_major=0 \
 	   stx_rdev_minor=0 \
 	   stx_nlink=1

base-commit: 623b4ea4082b8be71acaf261435d33fa4488993a
-- 
2.32.0