NSFS | versioning | copy_object - close chunkfs read stream to prevent stream being closed after stat

[nadavMiz]

Explain the changes

1. chunkfs is a Transform stream, however read_object_stream expects a write stream, so it only closes the write part. so the stream itself is still alive. it is later closed automatically (probably by garbage collector?), but this may happen after we call stat on the written file, so the mtime we stat is later modified when the stream is closed. this causes the mtime of the file to be different then that of the version. on GPFS we will not notice this until we call safe_move_posix that validates the inode and mtime of the file with the version, causing it to fail.

Issues: Fixed #8469

Testing Instructions:

1. run NC_CORETEST=true GPFS_ROOT_PATH=/ibm/fs1/tmp GPFS_DL_PATH="/usr/lpp/mmfs/lib/libgpfs.so" node ./node_modules/mocha/bin/mocha src/test/unit_tests/test_bucketspace_versioning.js on GPFS machine
2. ceph test: test_versioning_obj_suspended_copy

• Doc added/updated
• Tests added

[romayalon]

@nadavMiz and I had a discussion about ChunkFS being a Transform stream which is also a readable stream, this is causing us a lot of issues and redundant, per Nadav, @guymguym wrote some chunkFS code that omits the readable stream part, we should re-consider this solution again.

[romayalon]

Per our discussion -

1. We saw that when reproduced, the readable stream never gett closed and the writable stream get closed after the stat(), therefore the mtime changed after the close of the write stream, this caused the distinction between the mtime on the xattr and on the file. When closing the readable stream (using resume() we saw that the writeable stream is getting closed before the stat().
2. Please add the full explantation of this behavior above the resume().
3. If possible please add a dbg message when chunkfs is getting closed for follow-up.
   Approving.