Locking issue is back

[micbar]

Describe the bug

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Run CI decomposedFS concurrency test

Will run 63 of 64 specs
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1367 | ••••••••••••••••••••
1368 | ------------------------------
1369 | P [PENDING]
1370 | Decomposed concurrent Upload generates two revisions
1371 | /drone/src/pkg/storage/utils/decomposedfs/decomposedfs_concurrency_test.go:60
1372 | ------------------------------
1373 | • [FAILED] [0.990 seconds]
1374 | Decomposed
1375 | /drone/src/pkg/storage/utils/decomposedfs/decomposedfs_concurrency_test.go:36
1376 | concurrent
1377 | /drone/src/pkg/storage/utils/decomposedfs/decomposedfs_concurrency_test.go:53
1378 | CreateDir
1379 | /drone/src/pkg/storage/utils/decomposedfs/decomposedfs_concurrency_test.go:93
1380 | [It] handles already existing directories
1381 | /drone/src/pkg/storage/utils/decomposedfs/decomposedfs_concurrency_test.go:100
1382 |  
1383 | Unexpected error:
1384 | <*errors.withStack \| 0xc00000f278>: {
1385 | error: <*errors.withMessage \| 0xc0002601a0>{
1386 | cause: <*errors.errorString \| 0xc000256860>{
1387 | s: "unable to acquire a lock on the file",
1388 | },
1389 | msg: "xattrs: Unable to lock file for read",
1390 | },
1391 | stack: [0xd7d97a, 0xd8c6fc, 0xd8cce8, 0xe405b3, 0xe262c6, 0xfbc4d8, 0x49ee61],
1392 | }
1393 | xattrs: Unable to lock file for read: unable to acquire a lock on the file
1394 | occurred
1395 | In [It] at: /drone/src/pkg/storage/utils/decomposedfs/decomposedfs_concurrency_test.go:115

Expected behavior

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Actual behavior

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Setup

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OCIS_XXX=somevalue
OCIS_YYY=somevalue
PROXY_XXX=somevalue

Additional context

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[dragotin]

This is a typical log sequence from my Raspberry Pi where I get the error message often:

{"level":"error","service":"storage-users","pkg":"rgrpc","traceid":"00000000000000000000000000000000","error":"xattrs: Unable to lock file for read: unable to acquire a lock on the file","node":"7a17d9ea-25f8-49b7-963c-6cc2607f656f","time":"2022-10-24T12:54:54.263075324+01:00","message":"error listing attributes"}
{"level":"error","service":"storage-users","pkg":"rgrpc","traceid":"00000000000000000000000000000000","node":"7a17d9ea-25f8-49b7-963c-6cc2607f656f","error":"xattrs: Unable to lock file for read: unable to acquire a lock on the file","time":"2022-10-24T12:54:54.430718246+01:00","message":"error getting list of extended attributes"}
{"level":"debug","service":"storage-users","pkg":"rgrpc","traceid":"00000000000000000000000000000000","node":"7a17d9ea-25f8-49b7-963c-6cc2607f656f","ri":{"opaque":{"map":{"adler32":{"decoder":"plain","value":"MzI1ZTAxYTg="},"md5":{"decoder":"plain","value":"ZTg4OWJjMzM1NzI2MzEyNTcxMjk1NGViMzM0N2NkZDc="}}},"type":1,"id":{"opaque_id":"7a17d9ea-25f8-49b7-963c-6cc2607f656f","space_id":"f7fbf8c8-139b-4376-b307-cf0a8c2d0d9c"},"checksum":{"type":4,"sum":"96bdf56ca9541af02db4b3112f862daa915207bd"},"etag":"\"cfe5148ae1d195a619b72c90f983ca20\"","mime_type":"image/jpeg","mtime":{"seconds":1661700948},"path":"cameringo_20220828_165945.jpg","permission_set":{"add_grant":true,"create_container":true,"delete":true,"get_path":true,"get_quota":true,"initiate_file_download":true,"initiate_file_upload":true,"list_grants":true,"list_container":true,"list_file_versions":true,"list_recycle":true,"move":true,"remove_grant":true,"purge_recycle":true,"restore_file_version":true,"restore_recycle_item":true,"stat":true,"update_grant":true},"size":2671299,"owner":{"idp":"https://raspberrypi:9200","opaque_id":"f7fbf8c8-139b-4376-b307-cf0a8c2d0d9c","type":1},"arbitrary_metadata":{"metadata":{"http://owncloud.org/ns/favorite":""}},"parent_id":{"opaque_id":"4c191ecf-a009-47db-aa87-19ddc553dfad","space_id":"f7fbf8c8-139b-4376-b307-cf0a8c2d0d9c"},"name":"cameringo_20220828_165945.jpg"},"time":"2022-10-24T12:54:54.430946005+01:00","message":"AsResourceInfo"}

This seem to fail at the xattr.List() call in https://github.com/cs3org/reva/blob/master/pkg/storage/utils/decomposedfs/node/node.go#L636
I have no theory why, but I see this fail again and again (but not on every call).

xattr.List() uses a time loop to wait for being able to lock which goes up to > 50 msec. That should be enough... So maybe the file is already locked by a calling function? That would however mean that it fails at every call.