Added support for FUSE_EXPLICIT_INVAL_DATA to enable (#474)

diff --git a/ChangeLog.rst b/ChangeLog.rst
index a99f11df2f190e0ead6537e3f7b8111a61b431d6..57bd74381ab63519acb00f502db826abb6baf208 100644 (file)
--- a/ChangeLog.rst
+++ b/ChangeLog.rst
@@ -1,3 +1,9 @@
+Unreleased Changes
+==========================
+
+* Added support for FUSE_EXPLICIT_INVAL_DATA to enable
+  only invalidate cached pages on explicit request.
+
 libfuse 3.8.0 (2019-11-03)
 ==========================
 

diff --git a/example/printcap.c b/example/printcap.c
index 580f52ca73e585362755693800f3190ce37e73f3..904542f5124178d33820f7816b8d8b483a05fec3 100644 (file)
--- a/example/printcap.c
+++ b/example/printcap.c
@@ -79,6 +79,8 @@ static void pc_init(void *userdata,
                        printf("\tFUSE_CAP_POSIX_ACL\n");
        if(conn->capable & FUSE_CAP_NO_OPENDIR_SUPPORT)
                        printf("\tFUSE_CAP_NO_OPENDIR_SUPPORT\n");
+       if(conn->capable & FUSE_CAP_EXPLICIT_INVAL_DATA)
+                       printf("\tFUSE_CAP_EXPLICIT_INVAL_DATA\n");
        fuse_session_exit(se);
 }
 

diff --git a/include/fuse_common.h b/include/fuse_common.h
index 2d686b2ac46875d09b020a7f15a59c54ce52fab8..77d4bfec123d5ef09d83bb777b5a63b636b1f762 100644 (file)
--- a/include/fuse_common.h
+++ b/include/fuse_common.h
@@ -358,6 +358,29 @@ struct fuse_loop_config {
  */
 #define FUSE_CAP_NO_OPENDIR_SUPPORT    (1 << 24)
 
+/**
+ * Indicates support for invalidating cached pages only on explicit request.
+ *
+ * If this flag is set in the `capable` field of the `fuse_conn_info` structure,
+ * then the FUSE kernel module supports invalidating cached pages only on
+ * explicit request by the filesystem through fuse_lowlevel_notify_inval_inode()
+ * or fuse_invalidate_path().
+ *
+ * By setting this flag in the `want` field of the `fuse_conn_info` structure,
+ * the filesystem is responsible for invalidating cached pages through explicit
+ * requests to the kernel.
+ *
+ * Note that setting this flag does not prevent the cached pages from being
+ * flushed by OS itself and/or through user actions.
+ *
+ * Note that if both FUSE_CAP_EXPLICIT_INVAL_DATA and FUSE_CAP_AUTO_INVAL_DATA
+ * are set in the `capable` field of the `fuse_conn_info` structure then
+ * FUSE_CAP_AUTO_INVAL_DATA takes precedence.
+ *
+ * This feature is disabled by default.
+ */
+#define FUSE_CAP_EXPLICIT_INVAL_DATA    (1 << 25)
+
 /**
  * Ioctl flags
  *

diff --git a/lib/fuse_lowlevel.c b/lib/fuse_lowlevel.c
index f2d7038e34dd15b0ed349e6b14f73518044562a3..6eb949f8b36693325ee4da8539a171ffc0b3635a 100644 (file)
--- a/lib/fuse_lowlevel.c
+++ b/lib/fuse_lowlevel.c
@@ -1965,6 +1965,8 @@ static void do_init(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
                        se->conn.capable |= FUSE_CAP_HANDLE_KILLPRIV;
                if (arg->flags & FUSE_NO_OPENDIR_SUPPORT)
                        se->conn.capable |= FUSE_CAP_NO_OPENDIR_SUPPORT;
+               if (arg->flags & FUSE_EXPLICIT_INVAL_DATA)
+                       se->conn.capable |= FUSE_CAP_EXPLICIT_INVAL_DATA;
                if (!(arg->flags & FUSE_MAX_PAGES)) {
                        size_t max_bufsize =
                                FUSE_DEFAULT_MAX_PAGES_PER_REQ * getpagesize()
@@ -2085,6 +2087,8 @@ static void do_init(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
                outarg.flags |= FUSE_WRITEBACK_CACHE;
        if (se->conn.want & FUSE_CAP_POSIX_ACL)
                outarg.flags |= FUSE_POSIX_ACL;
+       if (se->conn.want & FUSE_CAP_EXPLICIT_INVAL_DATA)
+               outarg.flags |= FUSE_EXPLICIT_INVAL_DATA;
        outarg.max_readahead = se->conn.max_readahead;
        outarg.max_write = se->conn.max_write;
        if (se->conn.proto_minor >= 13) {