fuse/md-cache: add support for the 'fopen-keep-cache' mount option

fopen-keep-cache disables unconditional page-cache invalidations
on file open in fuse (via FOPEN_KEEP_CACHE) and replaces that
behavior with detection of remote changes and explicit
invalidations from mount/fuse. This option improves local caching
through the page cache and native client.

This change defines a new 'invalidate' translator callback to
identify when an inode's cache mapping has been determined to be
invalid. md-cache implements the policy to detect and invoke
inode invalidations. fuse-bridge and io-cache implement
invalidate handlers to invalidate the respective caches (page
cache in the case of fuse).

BUG: 833564
Change-Id: I99818da5777eaf06276c1c0b194669f5bab92d48
Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-on: http://review.gluster.com/3584
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Anand Avati <avati@redhat.com>

1 files changed, 18 insertions, 1 deletions

diff --git a/glusterfsd/src/glusterfsd.c b/glusterfsd/src/glusterfsd.c
index 0ab8fcd4c6d..76f01948193 100644
--- a/glusterfsd/src/glusterfsd.c
+++ b/glusterfsd/src/glusterfsd.c
@@ -168,6 +168,8 @@ static struct argp_option gf_options[] = {
          "Brick name to be registered with Gluster portmapper" },
         {"brick-port", ARGP_BRICK_PORT_KEY, "BRICK-PORT", OPTION_HIDDEN,
          "Brick Port to be registered with Gluster portmapper" },
+	{"fopen-keep-cache", ARGP_FOPEN_KEEP_CACHE_KEY, 0, 0,
+	 "Do not purge the cache on file open"},
 
         {0, 0, 0, 0, "Fuse options:"},
         {"direct-io-mode", ARGP_DIRECT_IO_MODE_KEY, "BOOL", OPTION_ARG_OPTIONAL,
@@ -368,6 +370,17 @@ create_fuse_mount (glusterfs_ctx_t *ctx)
                 }
         }
 
+	if (cmd_args->fopen_keep_cache) {
+		ret = dict_set_static_ptr(master->options, "fopen-keep-cache",
+			"on");
+		if (ret < 0) {
+			gf_log("glusterfsd", GF_LOG_ERROR,
+				"failed to set dict value for key "
+				"fopen-keep-cache");
+			goto err;
+		}
+	}
+
         switch (cmd_args->fuse_direct_io_mode) {
         case GF_OPTION_DISABLE: /* disable */
                 ret = dict_set_static_ptr (master->options, ZR_DIRECT_IO_OPT,
@@ -814,7 +827,11 @@ parse_opts (int key, char *arg, struct argp_state *state)
                 ctx = glusterfs_ctx_get ();
                 ctx->mem_accounting = 1;
                 break;
-        }
+
+	case ARGP_FOPEN_KEEP_CACHE_KEY:
+		cmd_args->fopen_keep_cache = 1;
+		break;
+	}
 
         return 0;
 }