linux-ext4 - [PATCH 31/31] fuse: implement freeze and shutdowns for iomap filesystems

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <176169811023.1424854.7225516717354931327.stgit@frogsfrogsfrogs>
Date: Tue, 28 Oct 2025 17:53:02 -0700
From: "Darrick J. Wong" <djwong@...nel.org>
To: djwong@...nel.org, miklos@...redi.hu
Cc: joannelkoong@...il.com, bernd@...ernd.com, neal@...pa.dev,
 linux-ext4@...r.kernel.org, linux-fsdevel@...r.kernel.org
Subject: [PATCH 31/31] fuse: implement freeze and shutdowns for iomap
 filesystems

From: Darrick J. Wong <djwong@...nel.org>

Implement filesystem freezing and block device shutdown notifications
for iomap-based servers

Signed-off-by: "Darrick J. Wong" <djwong@...nel.org>
---
 include/uapi/linux/fuse.h |   12 +++++++
 fs/fuse/inode.c           |   73 +++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 85 insertions(+)


diff --git a/include/uapi/linux/fuse.h b/include/uapi/linux/fuse.h
index 41e88f1089f1b9..5d10e471f2df7f 100644
--- a/include/uapi/linux/fuse.h
+++ b/include/uapi/linux/fuse.h
@@ -690,6 +690,10 @@ enum fuse_opcode {
 	FUSE_STATX		= 52,
 	FUSE_COPY_FILE_RANGE_64	= 53,
 
+	FUSE_FREEZE_FS		= 4089,
+	FUSE_UNFREEZE_FS	= 4090,
+	FUSE_SHUTDOWN_FS	= 4091,
+
 	FUSE_IOMAP_CONFIG	= 4092,
 	FUSE_IOMAP_IOEND	= 4093,
 	FUSE_IOMAP_BEGIN	= 4094,
@@ -1251,6 +1255,14 @@ struct fuse_syncfs_in {
 	uint64_t	padding;
 };
 
+struct fuse_freezefs_in {
+	uint64_t	unlinked;
+};
+
+struct fuse_shutdownfs_in {
+	uint64_t	flags;
+};
+
 /*
  * For each security context, send fuse_secctx with size of security context
  * fuse_secctx will be followed by security context name and this in turn
diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c
index c3f985baf21c77..d41a6e418537b5 100644
--- a/fs/fuse/inode.c
+++ b/fs/fuse/inode.c
@@ -1221,6 +1221,74 @@ static struct dentry *fuse_get_parent(struct dentry *child)
 	return parent;
 }
 
+#ifdef CONFIG_FUSE_IOMAP
+/*
+ * Second stage of a freeze. The data is already frozen so we only
+ * need to take care of the fuse server.
+ */
+static int fuse_freeze_fs(struct super_block *sb)
+{
+	struct fuse_mount *fm = get_fuse_mount_super(sb);
+	struct fuse_conn *fc = get_fuse_conn_super(sb);
+	struct fuse_freezefs_in inarg = {
+		.unlinked = atomic_long_read(&sb->s_remove_count),
+	};
+	FUSE_ARGS(args);
+	int err;
+
+	if (!fc->iomap)
+		return -EOPNOTSUPP;
+
+	args.opcode = FUSE_FREEZE_FS;
+	args.nodeid = get_node_id(sb->s_root->d_inode);
+	args.in_numargs = 1;
+	args.in_args[0].size = sizeof(inarg);
+	args.in_args[0].value = &inarg;
+	err = fuse_simple_request(fm, &args);
+	if (err == -ENOSYS)
+		err = -EOPNOTSUPP;
+	return err;
+}
+
+static int fuse_unfreeze_fs(struct super_block *sb)
+{
+	struct fuse_mount *fm = get_fuse_mount_super(sb);
+	struct fuse_conn *fc = get_fuse_conn_super(sb);
+	FUSE_ARGS(args);
+	int err;
+
+	if (!fc->iomap)
+		return 0;
+
+	args.opcode = FUSE_UNFREEZE_FS;
+	args.nodeid = get_node_id(sb->s_root->d_inode);
+	err = fuse_simple_request(fm, &args);
+	if (err == -ENOSYS)
+		err = 0;
+	return err;
+}
+
+static void fuse_shutdown_fs(struct super_block *sb)
+{
+	struct fuse_mount *fm = get_fuse_mount_super(sb);
+	struct fuse_conn *fc = get_fuse_conn_super(sb);
+	struct fuse_shutdownfs_in inarg = {
+		.flags = 0,
+	};
+	FUSE_ARGS(args);
+
+	if (!fc->iomap)
+		return;
+
+	args.opcode = FUSE_SHUTDOWN_FS;
+	args.nodeid = get_node_id(sb->s_root->d_inode);
+	args.in_numargs = 1;
+	args.in_args[0].size = sizeof(inarg);
+	args.in_args[0].value = &inarg;
+	fuse_simple_request(fm, &args);
+}
+#endif /* CONFIG_FUSE_IOMAP */
+
 /* only for fid encoding; no support for file handle */
 static const struct export_operations fuse_export_fid_operations = {
 	.encode_fh	= fuse_encode_fh,
@@ -1243,6 +1311,11 @@ static const struct super_operations fuse_super_operations = {
 	.statfs		= fuse_statfs,
 	.sync_fs	= fuse_sync_fs,
 	.show_options	= fuse_show_options,
+#ifdef CONFIG_FUSE_IOMAP
+	.freeze_fs	= fuse_freeze_fs,
+	.unfreeze_fs	= fuse_unfreeze_fs,
+	.shutdown	= fuse_shutdown_fs,
+#endif
 };
 
 static void sanitize_global_limit(unsigned int *limit)