From: Bernd Schubert <bschubert@ddn.com>
Date: Thu, 19 Sep 2024 13:03:55 +0000 (+0200)
Subject: Add fuse_set_feature_flag() / fuse_unset_feature_flag
X-Git-Tag: fuse-3.17.1-rc0~51
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=15f5c811239abca80eda2d988be7a9a9848f7c10;p=qemu-gpiodev%2Flibfuse.git

Add fuse_set_feature_flag() / fuse_unset_feature_flag

Simplify setting feature flags a bit by adding a helper
function.

Also move the check for valid flags into a funtion we can re-use
in a later patch.
---

diff --git a/example/passthrough_hp.cc b/example/passthrough_hp.cc
index bfaada5..1f6647f 100644
--- a/example/passthrough_hp.cc
+++ b/example/passthrough_hp.cc
@@ -190,36 +190,29 @@ static int get_fs_fd(fuse_ino_t ino) {
 static void sfs_init(void *userdata, fuse_conn_info *conn) {
     (void)userdata;
 
-    if (fs.passthrough && conn->capable & FUSE_CAP_PASSTHROUGH)
-        conn->want |= FUSE_CAP_PASSTHROUGH;
-    else
+    if (!fuse_set_feature_flag(conn, FUSE_CAP_PASSTHROUGH))
         fs.passthrough = false;
 
     /* Passthrough and writeback cache are conflicting modes */
-    if (fs.timeout && !fs.passthrough &&
-        conn->capable & FUSE_CAP_WRITEBACK_CACHE)
-        conn->want |= FUSE_CAP_WRITEBACK_CACHE;
+    if (fs.timeout && !fs.passthrough)
+        fuse_set_feature_flag(conn, FUSE_CAP_WRITEBACK_CACHE);
 
-    if (conn->capable & FUSE_CAP_FLOCK_LOCKS)
-        conn->want |= FUSE_CAP_FLOCK_LOCKS;
+    fuse_set_feature_flag(conn, FUSE_CAP_FLOCK_LOCKS);
 
     if (fs.nosplice) {
         // FUSE_CAP_SPLICE_READ is enabled in libfuse3 by default,
         // see do_init() in in fuse_lowlevel.c
         // Just unset both, in case FUSE_CAP_SPLICE_WRITE would also get enabled
         // by default.
-        conn->want &= ~FUSE_CAP_SPLICE_READ;
-        conn->want &= ~FUSE_CAP_SPLICE_WRITE;
+        fuse_unset_feature_flag(conn, FUSE_CAP_SPLICE_READ);
+        fuse_unset_feature_flag(conn, FUSE_CAP_SPLICE_WRITE);
     } else {
-        if (conn->capable & FUSE_CAP_SPLICE_WRITE)
-            conn->want |= FUSE_CAP_SPLICE_WRITE;
-        if (conn->capable & FUSE_CAP_SPLICE_READ)
-            conn->want |= FUSE_CAP_SPLICE_READ;
+        fuse_set_feature_flag(conn, FUSE_CAP_SPLICE_WRITE);
+        fuse_set_feature_flag(conn, FUSE_CAP_SPLICE_READ);
     }
 
     /* This is a local file system - no network coherency needed */
-    if (conn->capable & FUSE_CAP_DIRECT_IO_ALLOW_MMAP)
-        conn->want |= FUSE_CAP_DIRECT_IO_ALLOW_MMAP;
+    fuse_set_feature_flag(conn, FUSE_CAP_DIRECT_IO_ALLOW_MMAP);
 
     /* Disable the receiving and processing of FUSE_INTERRUPT requests */
     conn->no_interrupt = 1;
diff --git a/include/fuse_common.h b/include/fuse_common.h
index 38bac4e..1abac5a 100644
--- a/include/fuse_common.h
+++ b/include/fuse_common.h
@@ -7,6 +7,7 @@
 
 /** @file */
 
+#include <stdbool.h>
 #if !defined(FUSE_H_) && !defined(FUSE_LOWLEVEL_H_)
 #error "Never include <fuse_common.h> directly; use <fuse.h> or <fuse_lowlevel.h> instead."
 #endif
@@ -1034,6 +1035,23 @@ void fuse_loop_cfg_convert(struct fuse_loop_config *config,
 			   struct fuse_loop_config_v1 *v1_conf);
 #endif
 
+
+static inline bool fuse_set_feature_flag(struct fuse_conn_info *conn,
+					 uint64_t flag)
+{
+	if (conn->capable & flag) {
+		conn->want |= flag;
+		return true;
+	}
+	return false;
+}
+
+static inline void fuse_unset_feature_flag(struct fuse_conn_info *conn,
+					 uint64_t flag)
+{
+	conn->want &= ~flag;
+}
+
 /* ----------------------------------------------------------- *
  * Compatibility stuff					       *
  * ----------------------------------------------------------- */
diff --git a/lib/fuse_lowlevel.c b/lib/fuse_lowlevel.c
index ef1cda5..220a263 100644
--- a/lib/fuse_lowlevel.c
+++ b/lib/fuse_lowlevel.c
@@ -9,6 +9,7 @@
   See the file COPYING.LIB
 */
 
+#include <stdbool.h>
 #define _GNU_SOURCE
 
 #include "fuse_config.h"
@@ -1965,6 +1966,18 @@ static void do_lseek(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
 		fuse_reply_err(req, ENOSYS);
 }
 
+static bool want_flags_valid(uint64_t capable, uint64_t want)
+{
+	uint64_t unknown_flags = want & (~capable);
+	if (unknown_flags != 0) {
+		fuse_log(FUSE_LOG_ERR,
+			 "fuse: unknown connection 'want' flags: 0x%08lx\n",
+			unknown_flags);
+		return false;
+	}
+	return true;
+}
+
 /* Prevent bogus data races (bogus since "init" is called before
  * multi-threading becomes relevant */
 static __attribute__((no_sanitize("thread")))
@@ -2121,10 +2134,7 @@ void do_init(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
 	if (se->op.init)
 		se->op.init(se->userdata, &se->conn);
 
-	if (se->conn.want & (~se->conn.capable)) {
-		fuse_log(FUSE_LOG_ERR, "fuse: error: filesystem requested capabilities "
-			"0x%x that are not supported by kernel, aborting.\n",
-			se->conn.want & (~se->conn.capable));
+	if (!want_flags_valid(se->conn.capable, se->conn.want)) {
 		fuse_reply_err(req, EPROTO);
 		se->error = -EPROTO;
 		fuse_session_exit(se);