From 7fdd20ae5a1ced1faceab9cb0a6e553343911a0b Mon Sep 17 00:00:00 2001 From: Matthew Heon Date: Thu, 14 Feb 2019 17:25:58 -0500 Subject: Add initial version of renumber backend Renumber is a way of renumbering container locks after the number of locks available has changed. For now, renumber only works with containers. Signed-off-by: Matthew Heon --- libpod/lock/in_memory_locks.go | 9 +++++++++ libpod/lock/lock.go | 3 +++ libpod/lock/shm/shm_lock.c | 30 +++++++++++++++++++++++++++++ libpod/lock/shm/shm_lock.go | 16 +++++++++++++++ libpod/lock/shm/shm_lock.h | 1 + libpod/lock/shm/shm_lock_test.go | 28 ++++++++++++++++++++------- libpod/lock/shm_lock_manager_linux.go | 5 +++++ libpod/lock/shm_lock_manager_unsupported.go | 5 +++++ 8 files changed, 90 insertions(+), 7 deletions(-) (limited to 'libpod/lock') diff --git a/libpod/lock/in_memory_locks.go b/libpod/lock/in_memory_locks.go index db8f20e95..7eb22328f 100644 --- a/libpod/lock/in_memory_locks.go +++ b/libpod/lock/in_memory_locks.go @@ -89,3 +89,12 @@ func (m *InMemoryManager) RetrieveLock(id uint32) (Locker, error) { return m.locks[id], nil } + +// FreeAllLocks frees all locks +func (m *InMemoryManager) FreeAllLocks() error { + for _, lock := range m.locks { + lock.allocated = false + } + + return nil +} diff --git a/libpod/lock/lock.go b/libpod/lock/lock.go index 1f94171fe..b96393574 100644 --- a/libpod/lock/lock.go +++ b/libpod/lock/lock.go @@ -24,6 +24,9 @@ type Manager interface { // The underlying lock MUST be the same as another other lock with the // same UUID. RetrieveLock(id uint32) (Locker, error) + // FreeAllLocks frees all allocated locks, in preparation for lock + // reallocation. + FreeAllLocks() error } // Locker is similar to sync.Locker, but provides a method for freeing the lock diff --git a/libpod/lock/shm/shm_lock.c b/libpod/lock/shm/shm_lock.c index 4af58d857..367055823 100644 --- a/libpod/lock/shm/shm_lock.c +++ b/libpod/lock/shm/shm_lock.c @@ -407,6 +407,36 @@ int32_t deallocate_semaphore(shm_struct_t *shm, uint32_t sem_index) { return 0; } +// Deallocate all semaphores unconditionally. +// Returns negative ERRNO values. +int32_t deallocate_all_semaphores(shm_struct_t *shm) { + int ret_code; + uint i; + + if (shm == NULL) { + return -1 * EINVAL; + } + + // Lock the mutex controlling access to our shared memory + ret_code = take_mutex(&(shm->segment_lock)); + if (ret_code != 0) { + return -1 * ret_code; + } + + // Iterate through all bitmaps and reset to unused + for (i = 0; i < shm->num_bitmaps; i++) { + shm->locks[i].bitmap = 0; + } + + // Unlock the allocation control mutex + ret_code = release_mutex(&(shm->segment_lock)); + if (ret_code != 0) { + return -1 * ret_code; + } + + return 0; +} + // Lock a given semaphore // Does not check if the semaphore is allocated - this ensures that, even for // removed containers, we can still successfully lock to check status (and diff --git a/libpod/lock/shm/shm_lock.go b/libpod/lock/shm/shm_lock.go index 87d28e5c1..e70ea8743 100644 --- a/libpod/lock/shm/shm_lock.go +++ b/libpod/lock/shm/shm_lock.go @@ -155,6 +155,22 @@ func (locks *SHMLocks) DeallocateSemaphore(sem uint32) error { return nil } +// DeallocateAllSemaphores frees all semaphores so they can be reallocated to +// other containers and pods. +func (locks *SHMLocks) DeallocateAllSemaphores() error { + if !locks.valid { + return errors.Wrapf(syscall.EINVAL, "locks have already been closed") + } + + retCode := C.deallocate_all_semaphores(locks.lockStruct) + if retCode < 0 { + // Negative errno return from C + return syscall.Errno(-1 * retCode) + } + + return nil +} + // LockSemaphore locks the given semaphore. // If the semaphore is already locked, LockSemaphore will block until the lock // can be acquired. diff --git a/libpod/lock/shm/shm_lock.h b/libpod/lock/shm/shm_lock.h index 8e7e23fb7..58e4297e2 100644 --- a/libpod/lock/shm/shm_lock.h +++ b/libpod/lock/shm/shm_lock.h @@ -40,6 +40,7 @@ shm_struct_t *open_lock_shm(char *path, uint32_t num_locks, int *error_code); int32_t close_lock_shm(shm_struct_t *shm); int64_t allocate_semaphore(shm_struct_t *shm); int32_t deallocate_semaphore(shm_struct_t *shm, uint32_t sem_index); +int32_t deallocate_all_semaphores(shm_struct_t *shm); int32_t lock_semaphore(shm_struct_t *shm, uint32_t sem_index); int32_t unlock_semaphore(shm_struct_t *shm, uint32_t sem_index); diff --git a/libpod/lock/shm/shm_lock_test.go b/libpod/lock/shm/shm_lock_test.go index 594eb5d8e..830035881 100644 --- a/libpod/lock/shm/shm_lock_test.go +++ b/libpod/lock/shm/shm_lock_test.go @@ -4,7 +4,6 @@ import ( "fmt" "os" "runtime" - "syscall" "testing" "time" @@ -53,12 +52,8 @@ func runLockTest(t *testing.T, testFunc func(*testing.T, *SHMLocks)) { } defer func() { // Deallocate all locks - // Ignore ENOENT (lock is not allocated) - var i uint32 - for i = 0; i < numLocks; i++ { - if err := locks.DeallocateSemaphore(i); err != nil && err != syscall.ENOENT { - t.Fatalf("Error deallocating semaphore %d: %v", i, err) - } + if err := locks.DeallocateAllSemaphores(); err != nil { + t.Fatalf("Error deallocating semaphores: %v", err) } if err := locks.Close(); err != nil { @@ -212,6 +207,25 @@ func TestAllocateDeallocateCycle(t *testing.T) { }) } +// Test that DeallocateAllSemaphores deallocates all semaphores +func TestDeallocateAllSemaphoresDeallocatesAll(t *testing.T) { + runLockTest(t, func(t *testing.T, locks *SHMLocks) { + // Allocate a lock + locks1, err := locks.AllocateSemaphore() + assert.NoError(t, err) + + // Free all locks + err = locks.DeallocateAllSemaphores() + assert.NoError(t, err) + + // Allocate another lock + locks2, err := locks.AllocateSemaphore() + assert.NoError(t, err) + + assert.Equal(t, locks1, locks2) + }) +} + // Test that locks actually lock func TestLockSemaphoreActuallyLocks(t *testing.T) { runLockTest(t, func(t *testing.T, locks *SHMLocks) { diff --git a/libpod/lock/shm_lock_manager_linux.go b/libpod/lock/shm_lock_manager_linux.go index 94dfd7dd7..187661c8b 100644 --- a/libpod/lock/shm_lock_manager_linux.go +++ b/libpod/lock/shm_lock_manager_linux.go @@ -71,6 +71,11 @@ func (m *SHMLockManager) RetrieveLock(id uint32) (Locker, error) { return lock, nil } +// FreeAllLocks frees all locks in the manager +func (m *SHMLockManager) FreeAllLocks() error { + return m.locks.DeallocateAllSemaphores() +} + // SHMLock is an individual shared memory lock. type SHMLock struct { lockID uint32 diff --git a/libpod/lock/shm_lock_manager_unsupported.go b/libpod/lock/shm_lock_manager_unsupported.go index cbdb2f7bc..1d6e3fcbd 100644 --- a/libpod/lock/shm_lock_manager_unsupported.go +++ b/libpod/lock/shm_lock_manager_unsupported.go @@ -27,3 +27,8 @@ func (m *SHMLockManager) AllocateLock() (Locker, error) { func (m *SHMLockManager) RetrieveLock(id string) (Locker, error) { return nil, fmt.Errorf("not supported") } + +// FreeAllLocks is not supported on this platform +func (m *SHMLockManager) FreeAllLocks() error { + return fmt.Errorf("not supported") +} -- cgit v1.2.3-54-g00ecf