Abstract: Direct access to host memory for guests is disclosed. For example, a system includes a processor, a host memory, a filesystem daemon, a guest including a storage controller, and a filesystem queue accessible to the filesystem daemon and the storage controller. The storage controller receives a file retrieval request associated with a file stored in the host memory and forwards the file retrieval request to the filesystem daemon by adding the file retrieval request to the filesystem queue. The filesystem daemon retrieves the file retrieval request from the filesystem queue, determines a host memory address (HMA) associated with the file, and causes the HMA to be mapped to a guest memory address (GMA). The guest accesses the file in the host memory with the GMA, and later terminates access to the file, where the filesystem daemon is then configured cause the GMA to be unmapped.

Abstract: Direct access to host memory for guests is disclosed. For example, a system includes a processor, a host memory, a filesystem daemon, a guest including a storage controller, and a filesystem queue accessible to the filesystem daemon and the storage controller. The storage controller receives a file retrieval request associated with a file stored in the host memory and forwards the file retrieval request to the filesystem daemon by adding the file retrieval request to the filesystem queue. The filesystem daemon retrieves the file retrieval request from the filesystem queue, determines a host memory address (HMA) associated with the file, and causes the HMA to be mapped to a guest memory address (GMA). The guest accesses the file in the host memory with the GMA, and later terminates access to the file, where the filesystem daemon is then configured cause the GMA to be unmapped.

Abstract: Secure and efficient access to host memory for guests is disclosed. For example, a system includes (i) a processor, (ii) a host memory, (iii) a hypervisor including a filesystem daemon, (iv) a guest including a storage controller, and (v) a first filesystem queue. The storage controller is configured to receive a file request, translate the file request, and add the translated file request to a filesystem queue. The filesystem daemon is configured to retrieve the translated file request from the filesystem queue and provide access to a file in the host memory identified in the file request to the guest.

Abstract: Direct access to host memory for guests is disclosed. For example, a system includes a processor, a host memory, a filesystem daemon, a guest including a storage controller, and a filesystem queue accessible to the filesystem daemon and the storage controller. The storage controller receives a file retrieval request associated with a file stored in the host memory and forwards the file retrieval request to the filesystem daemon by adding the file retrieval request to the filesystem queue. The filesystem daemon retrieves the file retrieval request from the filesystem queue, determines a host memory address (HMA) associated with the file, and causes the HMA to be mapped to a guest memory address (GMA). The guest accesses the file in the host memory with the GMA, and later terminates access to the file, where the filesystem daemon is then configured cause the GMA to be unmapped.

Abstract: A system and method are disclosed for detecting and handling resource contention in a cluster file system. In one implementation, a processing device determines a measure of congestion for a resource that is shared by a first node of a cluster file system and a second node of the cluster file system, where the first node has a first local queue for lock requests for the resource, and wherein the second node has a second local queue for lock requests for the resource. The processing device adjusts a parameter for a node of the cluster file system in view of the measure of congestion.

Abstract: A system and method are disclosed for detecting and handling resource contention in a cluster file system. In one implementation, a processing device determines a measure of congestion for a resource that is shared by a first node of a cluster file system and a second node of the cluster file system, where the first node has a first local queue for lock requests for the resource, and wherein the second node has a second local queue for lock requests for the resource. The processing device adjusts a parameter for a node of the cluster file system in view of the measure of congestion.

Abstract: Some embodiments of a system and a method to detect contention for resource in a cluster file system have been presented. For instance, a processing device executable on a node in a cluster file system may put lock requests for a resource from the node into a local lock request queue, where multiple nodes in the cluster file system share the resource. Then the lock requests for the resource from this node and lock requests for the resource from other nodes may be tracked to measure congestion on the resource.

Abstract: A filesystem checker identifies a metadata block in a filesystem and determines a number of pointers pointing to the metadata block and a number of pointers embedded in the metadata block. The filesystem checker records the number of pointers pointing to the metadata block and the number of pointers embedded in the metadata block in a filesystem checker array. The filesystem checker verifies a consistency of the filesystem using data recorded in the filesystem checker array.

Abstract: A mechanism for inode event notification for cluster file systems is disclosed. A method of the invention includes implementing a lock scheme for a cache manager associated with an inode of a cluster file system, wherein the lock scheme includes a null lock (NL) used as a reference count for a lock value block (LVB) and an exclusive (EX) lock used for setting up inode event notifications, and associating a first global counter and a second global counter with the cache manager for the inode, wherein the first global counter is configured to track one or more processes that have the inode open in read-only mode and the second global counter is configured to track processes that have the inode open in read-write mode.

Abstract: A filesystem checker identifies a metadata block in a filesystem and determines a number of pointers pointing to the metadata block and a number of pointers embedded in the metadata block. The filesystem checker records the number of pointers pointing to the metadata block and the number of pointers embedded in the metadata block in a filesystem checker array. The filesystem checker verifies a consistency of the filesystem using data recorded in the filesystem checker array.

Abstract: Some embodiments of a system and a method to detect contention for resource in a cluster file system have been presented. For instance, a processing device may measure time spent performing actual operations by each of a set of nodes in a cluster file system when a respective node holds a lock on a resource and time spent performing overhead operations by the set of nodes without synchronization of clocks across the cluster file system. Then the processing device can determine latency and throughput of the cluster file system based on the time spent performing actual operations and the time spent performing overhead operations.

Abstract: A mechanism for inode event notification for cluster file systems is disclosed. A method of the invention includes implementing a lock scheme for a cache manager associated with an inode of a cluster file system, wherein the lock scheme includes a null lock (NL) used as a reference count for a lock value block (LVB) and an exclusive (EX) lock used for setting up inode event notifications, and associating a first global counter and a second global counter with the cache manager for the inode, wherein the first global counter is configured to track one or more processes that have the inode open in read-only mode and the second global counter is configured to track processes that have the inode open in read-write mode.

Abstract: Some embodiments of a system and a method to detect contention for resource in a cluster file system have been presented. For instance, a processing device executable on a node in a cluster file system may put lock requests for a resource from the node into a local lock request queue, where multiple nodes in the cluster file system share the resource. Then the lock requests for the resource from this node and lock requests for the resource from other nodes may be tracked to measure congestion on the resource.

Abstract: Some embodiments of a system and a method to detect contention for resource in a cluster file system have been presented. For instance, a processing device may measure time spent performing actual operations by each of a set of nodes in a cluster file system when a respective node holds a lock on a resource and time spent performing overhead operations by the set of nodes without synchronization of clocks across the cluster file system. Then the processing device can determine latency and throughput of the cluster file system based on the time spent performing actual operations and the time spent performing overhead operations.

Abstract: A method of and system for managing storage resources in a distributed file system is described. A lock for a storage resource is maintained on a lock-holding node. A master node that controls the lock-holding node receives a lock request from a requesting node. The lock request includes a request to obtain a lock for the storage resource, and a request to perform an action by the lock-holding node on the storage resource if the request to obtain the lock is not granted immediately.