To avoid this issue with refCounter refactor the code
such that
- locker() always increases refCount upon success
- unlocker() always decrements refCount upon success
(as a special case removes the resource if the
refCount is zero)
By these two assumptions we are able to see that we
are never granted two write lockers in any situation.
Thanks to @vcabbage for writing a nice reproducer.
Change distributed locking to allow taking bulk locks
across objects, reduces usually 1000 calls to 1.
Also allows for situations where multiple clients sends
delete requests to objects with following names
```
{1,2,3,4,5}
```
```
{5,4,3,2,1}
```
will block and ensure that we do not fail the request
on each other.
This PR implements locking from a global entity into
a more localized set level entity, allowing for locks
to be held only on the resources which are writing
to a collection of disks rather than a global level.
In this process this PR also removes the top-level
limit of 32 nodes to an unlimited number of nodes. This
is a precursor change before bring in bucket expansion.
This fix removes logrus package dependency and refactors the console
logging as the only logging mechanism by removing file logging support.
It rearranges the log message format and adds stack trace information
whenever trace information is not available in the error structure.
It also adds `--json` flag support for server logging.
When minio server is started with `--json` flag, all log messages are
displayed in json format, with no start-up and informational log
messages.
Fixes#5265#5220#5197
This is implemented so that the issues like in the
following flow don't affect the behavior of operation.
```
GetObjectInfo()
.... --> Time window for mutation (no lock held)
.... --> Time window for mutation (no lock held)
GetObject()
```
This happens when two simultaneous uploads are made
to the same object the object has returned wrong
info to the client.
Another classic example is "CopyObject" API itself
which reads from a source object and copies to
destination object.
Fixes#3370Fixes#2912
- abstract out instrumentation information.
- use separate lockInstance type that encapsulates the nsMutex, volume,
path and opsID as the frontend or top-level lock object.
These messages based on our prep stage during XL
and prints more informative message regarding
drive information.
This change also does a much needed refactoring.
- Instrumentation for locks.
- Detailed test coverage.
- Adding RPC control handler to fetch lock instrumentation.
- RPC control handlers suite tests with a test RPC server.
Anis Elleuch