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https://github.com/gluster/glusterd2.git
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af0da645c8
If a glusterd2 instance is already processing a cluster membership request (leave or join), return 409 (Conflict) to the other such client requests immediately. Signed-off-by: Prashanth Pai <ppai@redhat.com>
33 lines
884 B
Go
33 lines
884 B
Go
package utils
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import (
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"sync"
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"sync/atomic"
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"unsafe"
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)
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const mutexLocked = 1 << iota
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// MutexWithTry is a regular mutex with TryLock() functionality
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type MutexWithTry struct {
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sync.Mutex
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}
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// TryLock is the non-blocking version of Lock(). It returns true if the lock
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// is successfully acquired and false otherwise. This is functionally similar
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// to Lock.acquire(false) from Python's threading module and tryLock() from
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// Java.
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func (mwt *MutexWithTry) TryLock() bool {
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// Refer golang source: src/sync/mutex.go
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//
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// type Mutex struct {
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// state int32
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// sema uint32
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// }
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//
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// The first (unexported) member of sync.Mutex structure maintains the
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// internal state of the mutex. It's of type int32. The type, size and
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// offset of this state variable is very unlikely to change.
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return atomic.CompareAndSwapInt32((*int32)(unsafe.Pointer(mwt)), 0, mutexLocked)
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}
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