Re: [RFC] Passing extra mount options to unionmount tests

[Amir Goldstein <amir73il@gmail.com>]

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On Fri, Jul 31, 2020 at 3:35 PM Amir Goldstein <amir73il@gmail.com> wrote:
>
> > >
> > > If anyone is running unionmount-testsuite on regular basis
> > > I would be happy to know which configurations are being tested,
> > > because the test matrix grew considerably since I took over the project -
> > > both Overlayfs config options and the testsuite config options.
> >
> > For me, I think I am most interested in configuration used by
> > container runtimes (docker/podman). Docker seems to turn off
> > redirects as of now. podman is turning on metacopy (hence redirect)
> > by default now to see how do things go.
> >
> > So for me (redirect=on/off and metacopy=on/off) are important
> > configurations as of now. Having said that, I think I should talk
> > to container folks and encourage them to use "index" and "xino"
> > as well to be more posix like fs.
> >
>
> Hi Vivek,
>
> I remember you asked me about configuring extra mount options
> for unionmount but couldn't find that conversation, so replying to this
> related old discussion with my thoughts on the subject.
>
> Now that unionmount supports the environment variables:
> UNIONMOUNT_{BASEDIR,LOWERDIR,MNTPOINT}
>
> And now that xfstests has helpers to convert xfstests env vars to
> UNIONMOUNT_* env vars, one might ask: why won't we support
> UNIONMOUNT_OPTIONS=$OVERLAY_MOUNT_OPTIONS
>
> So when you asked me a question along those lines, my answer was that
> unionmount performs different validations depending on the test options,
> so for example, the test option ./run --meta adds the mount option
> "metacopy=on", but it also performs different validation tests, such as
> upper file st_blocks == 0 after metadata change.
>
> Right, so I gave a reason for why supporting extra mount options is not
> straight forward, but that doesn't mean that it is not possible.
> unionmount test could very well parse the extra mount options passed
> in env var and translate them to test config options.  As a matter of fact,
> unionmount already parses the following overlay module parameters
> and translates the following values to test config options:
>
> 1) redirect_dir does not exist => --xdev (expect EXDEV on dir rename)
> 2) redirect_dir exists and no explicit --xdev => add redirect_dir=on
> 3) index=N and --verify => add index=on and check st_ino validations
> 4) metacopy=Y => check --meta validations (e.g. upper st_blocks)
> 5) xino_auto=Y => add xino=on and check --xino validations (e.g. uniform st_dev)
>
> So apart from blindly adding the extra mount options to mount command,
> will also need to translate:
>
> 6) redirect_dir=off => --xdev
>    (redirect_dir=on conflicts with --xdev)
> 7) index=off => overrides index=on added by --verify
>    (st_ino validations should still pass on tests without multi layers)
> 8) metacopy=on => --meta
>    (metacopy=off conflicts with --meta)
> 9) xino=auto/on => --xino
>    (xino=off conflicts with --xino)
>
> At the moment, I have a patch to xfstests [1] that implements rule 8 in the
> xfstests _unionmount_testsuite_run helper, but I came to realize that would
> be wrong and that the correct way would be to implement conversion rules
> 6-9 in unionmount itself and then blindly assign in xfstest helper:
> UNIONMOUNT_OPTIONS=$OVL_BASE_MOUNT_OPTIONS
>

For whoever is interested, I implemented the above and pushed to:
https://github.com/amir73il/unionmount-testsuite/commits/mntopts

There are a few more corner cases I dealt with that are not mentioned above
(e.g. "redirect_dir=nofollow") as well as minor changes to "index" <=> --verify
dependency. For more details, see the commit message of attached patch.

There are a lot of combinations (mount options/module params/test options)
to test. I tested some manually, but might have missed something.

Thanks,
Amir.

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From 4e7028221af426415e7de87f3e10607fbb8e6b21 Mon Sep 17 00:00:00 2001
From: Amir Goldstein <amir73il@gmail.com>
Date: Wed, 12 Aug 2020 22:12:25 +0300
Subject: [PATCH] Add support for user defined mount options

Until this change, the mount options used for an overalyfs mount where
determined by:
1) Support in the kernel by checking module params
2) Test run options: --xdev, --verify, --xino, --meta

Apart from determining the overlayfs mount options, the test run options
also impact the test logic.  For example, after an operation that changes
a lower file metadata, the test verifies that an upper file exists.
Without --meta, the test verifies that the upper file has data, while
with --meta, the test verifies that the upper file does not have data.

The following test options are implied from overlayfs module parameters:
1) xino_auto=Y => --xino
2) metacopy=Y => --metacopy

Add support for adding arbitrary overalyfs mount options with the
environment variable UNIONMOUNT_MNTOPTIONS.

The user provided mount options will be used for an overalyfs mount
and extra mount options could be added on top of them with the existing
test run options (e.g. --meta).

In order to adapt the test logic to the effective mount options, the
following mount options imply the respective test options:
1) "redirect_dir="<NOT "on"> => --xdev
2) "nfs_export=on" => "index=on" => --verify
3) "xino=on" => --xino
4) "metacopy=on" => --meta

When mount and test options are in conflict, the test options wins.
For example: "metacopy=off" and --meta result in metacopy enabled.

Features disabled by mount options override module parameter.
For example: "metacopy=off" and metacopy=Y result in metacopy disabled.

The conflict resolution of "index=off" and --verify is a special case.
The test option --verify activates test verifications that are executed
after every filesystem operation.  Some of those verification may fail
on multi layer tests with index feature disabled due to broken hardlinks.

Until this change, --verify would auto enable the index feature, so
verifications will not fail in multi layer tests.  When mount option
"index=off" is provided, --verify does not auto enable index feature.

To conform with behavior of test options --xino and --meta, the --verify
test option is now also implied when index feature is enabled by default
via module parameter and not only by mount option.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
---
 mount_union.py   |  2 +-
 remount_union.py |  2 +-
 run              | 73 ++++++++++++++++++++++++++++++------------------
 settings.py      | 12 +++++---
 tool_box.py      | 18 ++++++++++++
 5 files changed, 74 insertions(+), 33 deletions(-)

diff --git a/mount_union.py b/mount_union.py
index aaaa242..8821695 100644
--- a/mount_union.py
+++ b/mount_union.py
@@ -41,7 +41,7 @@ def mount_union(ctx):
             os.mkdir(nested_upper)
             os.mkdir(nested_work)
 
-        mntopt = " -orw" + cfg.mntopts()
+        mntopt = " -o" + cfg.mntopts()
         if cfg.is_nested():
             nested_mntopt = mntopt
             if cfg.is_verify():
diff --git a/remount_union.py b/remount_union.py
index dc5525a..b2e8c3e 100644
--- a/remount_union.py
+++ b/remount_union.py
@@ -30,7 +30,7 @@ def remount_union(ctx, rotate_upper=False):
             workdir = layer_mntroot + "/w"
 
         mnt = union_mntroot
-        mntopt = " -orw" + cfg.mntopts()
+        mntopt = " -o" + cfg.mntopts()
         cmd = "mount -t " + cfg.fstype() + " " + cfg.fsname() + " " + mnt + mntopt + ",lowerdir=" + lowerlayers + ",upperdir=" + upperdir + ",workdir=" + workdir
         system(cmd)
         if cfg.is_verbose():
diff --git a/run b/run
index d841a45..4f35e51 100755
--- a/run
+++ b/run
@@ -103,35 +103,45 @@ if len(args) > 0 and args[0].startswith("--fuse="):
     cfg.set_fusefs(t)
     args = args[1:]
 
-if cfg.testing_none():
-    index = None
-    xino_auto = None
-    redirect_dir = None
-    metacopy = None
-elif cfg.is_fusefs():
-    # Don't check kernel module params for FUSE test and assume the following
-    # defaults, because user can disable redirect_dir with --xdev and user can
-    # enable index and xino with --verify
-    index = False
-    xino_auto = False
+xino = None
+index_def = None
+index_opt = None
+metacopy = None
+redirect_dir = None
+if cfg.is_fusefs():
+    # fuse-overlayfs only supports redirect_dir=off
+    # user can disable redirect_dir with --xdev
     redirect_dir = True
-    metacopy = False
 elif cfg.testing_overlayfs():
-    index = check_bool_modparam("index")
-    xino_auto = check_bool_modparam("xino_auto")
+    # Overlayfs feature "redirect_dir" is auto enabled with kernel version >= v4.10,
+    # unless explicitly disabled with --xdev or by mount option.  When redirect_dir
+    # is disabled, overlayfs tests skip rename tests that would result in EXDEV.
     redirect_dir = check_bool_modparam("redirect_dir")
-    # Overlayfs feature "redirect_dir" can be enabled with kernel version >= v4.10.
-    # Otherwise, overlayfs tests should skip rename tests that would result in EXDEV.
-    if redirect_dir is False:
+    redirect_dir_off = "redirect_dir" in cfg.mntopts() and not "redirect_dir=on" in cfg.mntopts()
+    if redirect_dir is False and not redirect_dir_off:
         cfg.add_mntopt("redirect_dir=on")
         redirect_dir = True
-    # xino can be enabled with kernel version >= v4.17
-    if xino_auto is True:
-        cfg.add_mntopt("xino=on")
+    # Overlayfs feature "index" can be enabled with --verify or by mount option on kernel version >= v4.13.
+    # When index is disabled some verifications in multi layer tests may fail due to broken hardlinks.
+    # When index is enabled we set_verify(), because all verifications are expected to pass.
+    index_def = check_bool_modparam("index")
+    if not index_def is None:
+        index_opt = check_bool_mntopt("index", cfg.mntopts(), None, onopt2="nfs_export=on")
+    if index_def or index_opt:
+        cfg.set_verify()
+    # Overlayfs feature "xino" can be enabled with --xino or by mount option on kernel version >= v4.17.
+    # When xino is enabled we set_xino(), so st_ino/st_dev verifications will work correctly.
+    xino_def = check_bool_modparam("xino_auto")
+    if not xino_def is None:
+        xino = check_bool_mntopt("xino", cfg.mntopts(), xino_def, onopt2="xino=auto")
+    if xino:
         cfg.set_xino()
-    # metacopy can be enabled with kernel version >= v4.19
-    metacopy = check_bool_modparam("metacopy")
-    if metacopy is True:
+    # Overlayfs feature "metacopy" can be enabled with --meta and by mount option on kernel version >= v4.19.
+    # When metacopy is enabled we set_metacopy(), so copy up verifications will work correctly.
+    metacopy_def = check_bool_modparam("metacopy")
+    if not metacopy_def is None:
+        metacopy = check_bool_mntopt("metacopy", cfg.mntopts(), metacopy_def, offopt2="nfs_export=on")
+    if metacopy:
         cfg.set_metacopy()
 
 maxfs = cfg.maxfs()
@@ -174,11 +184,11 @@ while len(args) > 0 and args[0].startswith("-"):
         termslash = "1"
     elif args[0] == "--xdev":
         # Disable "redirect_dir" and skip dir rename tests
-        if redirect_dir is True:
+        if redirect_dir:
             cfg.add_mntopt("redirect_dir=off")
             redirect_dir = False
     elif args[0] == "--xino":
-        if xino_auto is None:
+        if xino is None:
             print("xino not supported - ignoring --xino")
         else:
             cfg.add_mntopt("xino=on")
@@ -191,7 +201,8 @@ while len(args) > 0 and args[0].startswith("-"):
             cfg.set_metacopy()
     elif args[0] == "--verify":
         cfg.set_verify()
-        if index is False:
+        # auto enable index for --verify unless explicitly disabled
+        if index_def is False and not index_opt is False:
             cfg.add_mntopt("index=on")
     else:
         show_format("Invalid flag " + args[0])
@@ -296,7 +307,15 @@ for test in tests:
                 test_how += " --maxfs=" + str(maxfs)
             elif maxfs < 0:
                 test_how += " --samefs"
-        msg = cfg.progname() + " " + test_how + " --ts=" + termslash + " " + test
+            if not redirect_dir:
+                test_how += " --xdev"
+            if cfg.is_xino():
+                test_how += " --xino"
+            if cfg.is_metacopy():
+                test_how += " --meta"
+            if cfg.is_verify():
+                test_how += " --verify"
+        msg = cfg.progname() + " " + test_how + " " + test
         print("***");
         print("***", msg);
         print("***");
diff --git a/settings.py b/settings.py
index ffae527..b79e1f7 100644
--- a/settings.py
+++ b/settings.py
@@ -30,13 +30,18 @@ class config:
         self.__base_mntroot = os.getenv('UNIONMOUNT_BASEDIR')
         self.__lower_mntroot = os.getenv('UNIONMOUNT_LOWERDIR')
         self.__union_mntroot = os.getenv('UNIONMOUNT_MNTPOINT')
+        self.__mntopts = os.getenv('UNIONMOUNT_MNTOPTIONS')
         print("Environment variables:")
         if self.__base_mntroot:
-            print("UNIONMOUNT_BASEDIR=" + self.__base_mntroot)
+            print("UNIONMOUNT_BASEDIR='" + self.__base_mntroot + "'")
         if self.__lower_mntroot:
-            print("UNIONMOUNT_LOWERDIR=" + self.__lower_mntroot)
+            print("UNIONMOUNT_LOWERDIR='" + self.__lower_mntroot + "'")
         if self.__union_mntroot:
-            print("UNIONMOUNT_MNTPOINT=" + self.__union_mntroot)
+            print("UNIONMOUNT_MNTPOINT='" + self.__union_mntroot + "'")
+        if self.__mntopts:
+            print("UNIONMOUNT_MNTOPTIONS='" + self.__mntopts + "'")
+        else: # Use arbitrary non empty string to simplify add_mntopt()
+            self.__mntopts = "rw"
         print()
         if self.__base_mntroot and not self.__lower_mntroot:
             # Empty UNIONMOUNT_LOWERDIR with non-empty UNIONMOUNT_BASEDIR imply --samefs
@@ -50,7 +55,6 @@ class config:
         self.__metacopy = False
         self.__nested = False
         self.__xino = False
-        self.__mntopts = ""
         self.__fusefs = False
         self.__fstype = "overlay"
         self.__fsname = "overlay"
diff --git a/tool_box.py b/tool_box.py
index 03506fe..bf1f578 100644
--- a/tool_box.py
+++ b/tool_box.py
@@ -64,3 +64,21 @@ def check_bool_modparam(param):
     except FileNotFoundError:
         return None
     return value.startswith("Y")
+
+#
+# Check if overlay feature is enabled by mount option
+#
+# Return 'default' if mount option was not provided
+#
+def check_bool_mntopt(feature, mntopts, default, onopt2=None, offopt2=None):
+    onopt = feature + "=on"
+    offopt = feature + "=off"
+    on = onopt in mntopts or (onopt2 and onopt2 in mntopts)
+    off = offopt in mntopts or (offopt2 and offopt2 in mntopts)
+    if on and off:
+        raise RuntimeError("Conflicting mount options w.r.t feature '" + feature + "': " + mntopts)
+    if on:
+        return True
+    if off:
+        return False
+    return default;
-- 
2.17.1