Adding ZTS test for O_APPEND

Commit 63b18e4 fixed an issue in zpl_aio_write() to make sure that
kiocb->ki_pos was updated correctly when opening a file with O_APPEND.
Adding a test to verify O_APPEND functionality with lseek can make
sure that all other distros/kernel versions also have the correct
behavior.

Also moved the threadappends_001_pos test into this append test
directory in functional ZTS directory. This way the two append tests
are together for organization purposes.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Brian Atkinson <batkinson@lanl.gov>
Closes #13424

tests/runfiles/common.run

@@ -40,6 +40,10 @@ tests = ['alloc_class_001_pos', 'alloc_class_002_neg', 'alloc_class_003_pos',
     'alloc_class_013_pos']
 tags = ['functional', 'alloc_class']
 
+[tests/functional/append]
+tests = ['file_append', 'threadsappend_001_pos']
+tags = ['functional', 'append']
+
 [tests/functional/arc]
 tests = ['dbufstats_001_pos', 'dbufstats_002_pos', 'dbufstats_003_pos',
     'arcstats_runtime_tuning']
@@ -884,10 +888,6 @@ tests = ['suid_write_to_suid', 'suid_write_to_sgid', 'suid_write_to_suid_sgid',
     'suid_write_to_none', 'suid_write_zil_replay']
 tags = ['functional', 'suid']
 
-[tests/functional/threadsappend]
-tests = ['threadsappend_001_pos']
-tags = ['functional', 'threadsappend']
-
 [tests/functional/trim]
 tests = ['autotrim_integrity', 'autotrim_config', 'autotrim_trim_integrity',
     'trim_integrity', 'trim_config', 'trim_l2arc']

tests/runfiles/sanity.run

@@ -584,7 +584,7 @@ tests = ['suid_write_to_suid', 'suid_write_to_sgid', 'suid_write_to_suid_sgid',
     'suid_write_to_none']
 tags = ['functional', 'suid']
 
-[tests/functional/threadsappend]
+[tests/functional/append]
 tests = ['threadsappend_001_pos']
 tags = ['functional', 'threadsappend']