Ensure that the DF endpoint updated volume refcount

[mheon]

The field was already exposed already in the system df output so this just required a bit of plumbing and testing.

Fixes #15720

Fixed a bug where the Compat Disk Usage endpoint did not properly report the reference count of volumes.

[vrothberg]

LGTM
@benoitf FYI

[edsantiago]

Looks like this should be ....UsageData.Refcount

[edsantiago]

Looks unimplemented: I see no field with anything looking like RefCount.

Handy tip: this is how I debug APIv2 tests:

t GET ... 200 sdf   <------ the "sdf" is the important thing

Since sdf does not match, the test just dumps the entire return value, in this case:

not ok 21 [45-system] GET libpod/system/df : output                                                                                                             
#  expected: dsf                                                                                                                                                
#    actual: {"Images":[],"Containers":[],"Volumes":[{"VolumeName":"foo1","Links":0,"Size":0,"ReclaimableSize":0}]}                                             
not ok 22 [45-system] GET libpod/system/df : .Volumes[0].RefCount                                                                                               
#  expected: 0                                                                                                                                                  
#    actual: null              

And OBTW the POST containers/create is failing too

[edsantiago]

Container Create is still broken. From looking at other tests, I figured out that you need brackets. Then I figured out that you need a podman pull (which is stupid, the image should be preloaded, but I've kind of lost track of this test suite and bad things have happened).

diff --git a/test/apiv2/45-system.at b/test/apiv2/45-system.at
index 061fe5f98..096df5516 100644
--- a/test/apiv2/45-system.at
+++ b/test/apiv2/45-system.at
@@ -29,7 +29,8 @@ t GET libpod/system/df 200 '.Volumes[0].VolumeName=foo1'                                                                                     
 t GET system/df 200 '.Volumes[0].UsageData.RefCount=0'
 
 # Make a container using the volume
-t POST containers/create Image=$IMAGE Volumes='{"/test":{}}' HostConfig='{"Binds":"foo1:/test"}' 201 \
+podman pull $IMAGE &>/dev/null
+t POST containers/create Image=$IMAGE Volumes='{"/test":{}}' HostConfig='{"Binds":["foo1:/test"]}' 201 \
   .Id~[0-9a-f]\\{64\\}                                                            ^------------^
 cid=$(jq -r '.Id' <<<"$output")

And, something is still broken, because even after the container create the following test fails:

not ok 23 [45-system] GET system/df : .Volumes[0].UsageData.RefCount                                                                                            
#  expected: 1                                                                                                                                                  
#    actual: 0    

[mheon]

Volumes are apparently only considered in use if the container using them is running.

That doesn't seem right...

[mheon]

Apparently was done deliberately. Let me check and see if Docker does it.

[mheon]

Nope. Docker considers a volume active if it is used by any container, even one not running.

[mheon]

Repushed with test fix and a change to podman system df to better match Docker. We'll see if that breaks any tests.

[rhatdan]

/lgtm
/hold

[rhatdan]

/lgtm

[edsantiago]

Should be an easy fix:

diff --git a/test/system/320-system-df.bats b/test/system/320-system-df.bats
index 217357b37..35e121c62 100644
--- a/test/system/320-system-df.bats
+++ b/test/system/320-system-df.bats
@@ -27,7 +27,7 @@ function teardown() {                                                                                                                        
     run_podman system df --format '{{ .Type }}:{{ .Total }}:{{ .Active }}'
     is "${lines[0]}" "Images:1:1"        "system df : Images line"
     is "${lines[1]}" "Containers:2:1"    "system df : Containers line"
-    is "${lines[2]}" "Local Volumes:2:1" "system df : Volumes line"
+    is "${lines[2]}" "Local Volumes:2:2" "system df : Volumes line"
 
     # Try -v. (Grrr. No way to specify individual formats)
     #

Looking back at the history of this test, I wrote it the way I did because that's the way the code worked. I made no attempt to understand whether or not it was correct.

[edsantiago]

/lgtm

[edsantiago]

Flakes are all registry-related (on the registry end). Restarted once, all failed. Restarted twice, going to bed, SEP.

[vrothberg]

LGTM
/hold cancel

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