power: always freeze efivarfs

The efivarfs filesystems must always be frozen and thawed to resync
variable state. Make it so.

Link: https://patch.msgid.link/20251105-vorbild-zutreffen-fe00d1dd98db@brauner
Signed-off-by: Christian Brauner <brauner@kernel.org>

Author: brauner

fs/efivarfs/super.c

@@ -533,6 +533,7 @@ static struct file_system_type efivarfs_type = {
 	.init_fs_context = efivarfs_init_fs_context,
 	.kill_sb = efivarfs_kill_sb,
 	.parameters = efivarfs_parameters,
+	.fs_flags = FS_POWER_FREEZE,
 };
 
 static __init int efivarfs_init(void)

fs/super.c

@@ -1183,11 +1183,14 @@ static inline bool get_active_super(struct super_block *sb)
 
 static const char *filesystems_freeze_ptr = "filesystems_freeze";
 
-static void filesystems_freeze_callback(struct super_block *sb, void *unused)
+static void filesystems_freeze_callback(struct super_block *sb, void *freeze_all_ptr)
 {
 	if (!sb->s_op->freeze_fs && !sb->s_op->freeze_super)
 		return;
 
+	if (freeze_all_ptr && !(sb->s_type->fs_flags & FS_POWER_FREEZE))
+		return;
+
 	if (!get_active_super(sb))
 		return;
 
@@ -1201,9 +1204,13 @@ static void filesystems_freeze_callback(struct super_block *sb, void *unused)
 	deactivate_super(sb);
 }
 
-void filesystems_freeze(void)
+void filesystems_freeze(bool freeze_all)
 {
-	__iterate_supers(filesystems_freeze_callback, NULL,
+	void *freeze_all_ptr = NULL;
+
+	if (freeze_all)
+		freeze_all_ptr = &freeze_all;
+	__iterate_supers(filesystems_freeze_callback, freeze_all_ptr,
 			 SUPER_ITER_UNLOCKED | SUPER_ITER_REVERSE);
 }
 

include/linux/fs.h

@@ -2689,6 +2689,7 @@ struct file_system_type {
 #define FS_ALLOW_IDMAP         32      /* FS has been updated to handle vfs idmappings. */
 #define FS_MGTIME		64	/* FS uses multigrain timestamps */
 #define FS_LBS			128	/* FS supports LBS */
+#define FS_POWER_FREEZE		256	/* Always freeze on suspend/hibernate */
 #define FS_RENAME_DOES_D_MOVE	32768	/* FS will handle d_move() during rename() internally. */
 	int (*init_fs_context)(struct fs_context *);
 	const struct fs_parameter_spec *parameters;
@@ -3606,7 +3607,7 @@ extern void drop_super_exclusive(struct super_block *sb);
 extern void iterate_supers(void (*f)(struct super_block *, void *), void *arg);
 extern void iterate_supers_type(struct file_system_type *,
 			        void (*)(struct super_block *, void *), void *);
-void filesystems_freeze(void);
+void filesystems_freeze(bool freeze_all);
 void filesystems_thaw(void);
 
 extern int dcache_dir_open(struct inode *, struct file *);

kernel/power/hibernate.c

@@ -825,8 +825,7 @@ int hibernate(void)
 		goto Restore;
 
 	ksys_sync_helper();
-	if (filesystem_freeze_enabled)
-		filesystems_freeze();
+	filesystems_freeze(filesystem_freeze_enabled);
 
 	error = freeze_processes();
 	if (error)
@@ -932,8 +931,7 @@ int hibernate_quiet_exec(int (*func)(void *data), void *data)
 	if (error)
 		goto restore;
 
-	if (filesystem_freeze_enabled)
-		filesystems_freeze();
+	filesystems_freeze(filesystem_freeze_enabled);
 
 	error = freeze_processes();
 	if (error)
@@ -1083,8 +1081,7 @@ static int software_resume(void)
 	if (error)
 		goto Restore;
 
-	if (filesystem_freeze_enabled)
-		filesystems_freeze();
+	filesystems_freeze(filesystem_freeze_enabled);
 
 	pm_pr_dbg("Preparing processes for hibernation restore.\n");
 	error = freeze_processes();

kernel/power/suspend.c

@@ -375,8 +375,7 @@ static int suspend_prepare(suspend_state_t state)
 	if (error)
 		goto Restore;
 
-	if (filesystem_freeze_enabled)
-		filesystems_freeze();
+	filesystems_freeze(filesystem_freeze_enabled);
 	trace_suspend_resume(TPS("freeze_processes"), 0, true);
 	error = suspend_freeze_processes();
 	trace_suspend_resume(TPS("freeze_processes"), 0, false);