freebsd-nq/tests
Alan Somers 13d593a5b0 Fix a race in fusefs that can corrupt a file's size.
VOPs like VOP_SETATTR can change a file's size, with the vnode
exclusively locked.  But VOPs like VOP_LOOKUP look up the file size from
the server without the vnode locked.  So a race is possible.  For
example:

1) One thread calls VOP_SETATTR to truncate a file.  It locks the vnode
   and sends FUSE_SETATTR to the server.
2) A second thread calls VOP_LOOKUP and fetches the file's attributes from
   the server.  Then it blocks trying to acquire the vnode lock.
3) FUSE_SETATTR returns and the first thread releases the vnode lock.
4) The second thread acquires the vnode lock and caches the file's
   attributes, which are now out-of-date.

Fix this race by recording a timestamp in the vnode of the last time
that its filesize was modified.  Check that timestamp during VOP_LOOKUP
and VFS_VGET.  If it's newer than the time at which FUSE_LOOKUP was
issued to the server, ignore the attributes returned by FUSE_LOOKUP.

PR:		259071
Reported by:	Agata <chogata@moosefs.pro>
Reviewed by:	pfg
MFC after:	2 weeks
Differential Revision: https://reviews.freebsd.org/D33158
2021-12-31 17:38:42 -07:00
..
etc
freebsd_test_suite Fix sys/opencrypto/blake2_test when kern.cryptodevallowsoft=0 2018-08-16 23:49:56 +00:00
sys Fix a race in fusefs that can corrupt a file's size. 2021-12-31 17:38:42 -07:00
Kyuafile
Makefile Tag /usr/tests/local symlink with package=tests 2020-01-23 15:59:30 +00:00
Makefile.depend
Makefile.inc0
README Do not recommend to install kyua with pkg in the tests README 2020-10-27 09:53:49 +00:00

src/tests: The FreeBSD test suite
=================================

Usage of the FreeBSD test suite:
(1)  Run the tests:
       kyua test -k /usr/tests/Kyuafile
(2)  See the test results:
       kyua report

For further information on using the test suite, read tests(7):
       man tests

Description of FreeBSD test suite
=================================
The build of the test suite is organized in the following manner:

* The build of all test artifacts is protected by the MK_TESTS knob.
  The user can disable these with the WITHOUT_TESTS setting in
  src.conf(5).

* The goal for /usr/tests/ (the installed test programs) is to follow
  the same hierarchy as /usr/src/ wherever possible, which in turn drives
  several of the design decisions described below.  This simplifies the
  discoverability of tests.  We want a mapping such as:

    /usr/src/bin/cp/      -> /usr/tests/bin/cp/
    /usr/src/lib/libc/    -> /usr/tests/lib/libc/
    /usr/src/usr.bin/cut/ -> /usr/tests/usr.bin/cut/
    ... and many more ...

* Test programs for specific utilities and libraries are located next
  to the source code of such programs.  For example, the tests for the
  src/lib/libcrypt/ library live in src/lib/libcrypt/tests/.  The tests/
  subdirectory is optional and should, in general, be avoided.

* The src/tests/ hierarchy (this directory) provides generic test
  infrastructure and glue code to join all test programs together into
  a single test suite definition.

* The src/tests/ hierarchy also includes cross-functional test programs:
  i.e. test programs that cover more than a single utility or library
  and thus don't fit anywhere else in the tree.  Consider this to follow
  the same rationale as src/share/man/: this directory contains generic
  manual pages while the manual pages that are specific to individual
  tools or libraries live next to the source code.

In order to keep the src/tests/ hierarchy decoupled from the actual test
programs being installed --which is a worthy goal because it simplifies
the addition of new test programs and simplifies the maintenance of the
tree-- the top-level Kyuafile does not know which subdirectories may
exist upfront.  Instead, such Kyuafile automatically detects, at
run-time, which */Kyuafile files exist and uses those directly.

Similarly, every directory in src/ that wants to install a Kyuafile to
just recurse into other subdirectories reuses this Kyuafile with
auto-discovery features.  As an example, take a look at src/lib/tests/
whose sole purpose is to install a Kyuafile into /usr/tests/lib/.
The goal in this specific case is for /usr/tests/lib/ to be generated
entirely from src/lib/.

-- 
$FreeBSD$