diff options
| -rw-r--r-- | src/server/image.c | 20 |
1 files changed, 11 insertions, 9 deletions
diff --git a/src/server/image.c b/src/server/image.c index cd5b47f..012a88e 100644 --- a/src/server/image.c +++ b/src/server/image.c @@ -177,6 +177,7 @@ void image_saveAllCacheMaps() { spin_lock( &imageListLock ); for (int i = 0; i < _num_images; ++i) { + if ( _images[i] == NULL ) continue; _images[i]->users++; spin_unlock( &imageListLock ); image_saveCacheMap( _images[i] ); @@ -325,18 +326,19 @@ dnbd3_image_t* image_lock(dnbd3_image_t *image) dnbd3_image_t* image_release(dnbd3_image_t *image) { if ( image == NULL ) return NULL; + spin_lock( &imageListLock ); spin_lock( &image->lock ); assert( image->users > 0 ); image->users--; - if ( image->users > 0 ) { // Still in use, do nothing - spin_unlock( &image->lock ); + bool inUse = image->users != 0; + spin_unlock( &image->lock ); + if ( inUse ) { // Still in use, do nothing + spin_unlock( &imageListLock ); return NULL; } - spin_unlock( &image->lock ); // Getting here means we decreased the usage counter to zero // If the image is not in the images list anymore, we're // responsible for freeing it - spin_lock( &imageListLock ); for (int i = 0; i < _num_images; ++i) { if ( _images[i] == image ) { // Found, do nothing spin_unlock( &imageListLock ); @@ -344,10 +346,8 @@ dnbd3_image_t* image_release(dnbd3_image_t *image) } } spin_unlock( &imageListLock ); - // So it wasn't in the images list anymore either, get rid of it, - // but check usage count once again, since it might have been increased - // after we unlocked above - if ( image->users == 0 ) image_free( image ); + // So it wasn't in the images list anymore either, get rid of it + if ( !inUse ) image = image_free( image ); return NULL; } @@ -358,16 +358,18 @@ dnbd3_image_t* image_release(dnbd3_image_t *image) */ void image_remove(dnbd3_image_t *image) { + bool wasInList = false; spin_lock( &imageListLock ); spin_lock( &image->lock ); for (int i = _num_images - 1; i >= 0; --i) { if ( _images[i] != image ) continue; _images[i] = NULL; + wasInList = true; if ( i + 1 == _num_images ) _num_images--; } - if ( image->users <= 0 ) image = image_free( image ); spin_unlock( &image->lock ); spin_unlock( &imageListLock ); + if ( wasInList && image->users == 0 ) image = image_free( image ); } /** |