[LTP] [PATCH v3 4/4] doc: Update docs on filesystem detection

Cyril Hrubis
2021-03-17T10:53:18Z

Signed-off-by: Cyril Hrubis <chrubis@suse.cz>
---
doc/test-writing-guidelines.txt | 47 +++++++++++++++++++++++----------
1 file changed, 33 insertions(+), 14 deletions(-)

diff --git a/doc/test-writing-guidelines.txt b/doc/test-writing-guidelines.txt
index 50696e14a..79642810c 100644
--- a/doc/test-writing-guidelines.txt
+++ b/doc/test-writing-guidelines.txt
@@ -978,39 +978,58 @@ LTP_ALIGN(x, a)

Aligns the x to be next multiple of a. The a must be power of 2.

-2.2.13 Filesystem type detection
-^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+2.2.13 Filesystem type detection and skiplist
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Some tests are known to fail on certain filesystems (you cannot swap on TMPFS,
there are unimplemented 'fcntl()' etc.).

-If your test needs to be skipped on certain filesystems, use the interface
-below:
+If your test needs to be skipped on certain filesystems use the
+'.skip_filesystems' field in the tst_test structure as follows:

[source,c]
-------------------------------------------------------------------------------
#include "tst_test.h"

- /*
- * Unsupported only on NFS.
- */
- if (tst_fs_type(".") == TST_NFS_MAGIC)
- tst_brk(TCONF, "Test not supported on NFS filesystem");
+static struct tst_test test = {
+ ...
+ .skip_filesystems = (const char *const []) {
+ "tmpfs",
+ "ramfs",
+ "nfs",
+ NULL
+ },
+};
+-------------------------------------------------------------------------------

+When the '.all_filesystem' flag is set the '.skip_filesystems' list is passed
+to the function that detects supported filesystems any listed filesystem is
+not included in the resulting list of supported filesystems.

- /*
- * Unsupported on NFS, TMPFS and RAMFS
- */
- long type;
+If test needs to adjust expectations based on filesystem type it's also
+possible to detect filesystem type at the runtime. This is preferably used
+when only subset of the test is not applicable for a given filesystem.
+
+[source,c]
+-------------------------------------------------------------------------------
+#include "tst_test.h"
+
+static void run(void)
+{
+ ...

switch ((type = tst_fs_type("."))) {
case TST_NFS_MAGIC:
case TST_TMPFS_MAGIC:
case TST_RAMFS_MAGIC:
- tst_brk(TCONF, "Test not supported on %s filesystem",
+ tst_brk(TCONF, "Subtest not supported on %s",
tst_fs_type_name(type));
+ return;
break;
}
+
+ ...
+}
-------------------------------------------------------------------------------

2.2.14 Thread-safety in the LTP library
--
2.26.2