fuse: add more control over cache invalidation behaviour

Currently userspace is able to notify the kernel to invalidate the cache for an inode. This means that, if all the inodes in a filesystem need to be invalidated, then userspace needs to iterate through all of them and do this kernel notification separately. This patch adds the concept of 'epoch': each fuse connection will have the current epoch initialized and every new dentry will have it's d_time set to the current epoch value. A new operation will then allow userspace to increment the epoch value. Every time a dentry is d_revalidate()'ed, it's epoch is compared with the current connection epoch and invalidated if it's value is different.

Luis Henriques committed 1 year ago

Commit 23963561 parent faa794d6 files · +50 −6Browse files

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include/uapi/linux/fuse.h+5−1

  *
  *  7.43
  *  - add FUSE_REQUEST_TIMEOUT
+ *
+ *  7.44
+ *  - add FUSE_NOTIFY_INC_EPOCH
  */
 #ifndef _LINUX_FUSE_H
 #define FUSE_KERNEL_VERSION 7
 /** Minor version number of this interface */
-#define FUSE_KERNEL_MINOR_VERSION 43
+#define FUSE_KERNEL_MINOR_VERSION 44
 /** The node ID of the root inode */
 #define FUSE_ROOT_ID 1
 	FUSE_NOTIFY_RETRIEVE = 5,
 	FUSE_NOTIFY_DELETE = 6,
 	FUSE_NOTIFY_RESEND = 7,
+	FUSE_NOTIFY_INC_EPOCH = 8,
 	FUSE_NOTIFY_CODE_MAX,
 };