Currently, when setting efi variables through the runtime service,
efivarfs cannot sync variable updates properly. Introduce efivarfs
refresh remount to support efivarfs information updates from other
sources.
Signed-off-by: Weizhao Ouyang <o451686892@xxxxxxxxx>
---
Documentation/filesystems/efivarfs.rst | 6 ++++
fs/efivarfs/super.c | 40 +++++++++++++++++++++++++-
2 files changed, 45 insertions(+), 1 deletion(-)
diff --git a/Documentation/filesystems/efivarfs.rst b/Documentation/filesystems/efivarfs.rst
index f646c3f0980f..58461e02ad01 100644
--- a/Documentation/filesystems/efivarfs.rst
+++ b/Documentation/filesystems/efivarfs.rst
@@ -18,6 +18,12 @@ efivarfs is typically mounted like this::
mount -t efivarfs none /sys/firmware/efi/efivars
+To support efivar updates from other sources (efi_test ioctl, runtime
+driver, etc.), set ``efivarfs.refresh=1``. After that, remount will
+update the efivar information in efivarfs, like this::
+
+ mount -t efivarfs none /sys/firmware/efi/efivars -o remount
+
Due to the presence of numerous firmware bugs where removing non-standard
UEFI variables causes the system firmware to fail to POST, efivarfs
files that are not well-known standardized variables are created
diff --git a/fs/efivarfs/super.c b/fs/efivarfs/super.c
index beba15673be8..7ae22ca120e3 100644
--- a/fs/efivarfs/super.c
+++ b/fs/efivarfs/super.c
@@ -277,6 +277,44 @@ static const struct fs_parameter_spec efivarfs_parameters[] = {
{},
};
+static bool efivarfs_refresh_default __read_mostly;
+module_param_named(refresh, efivarfs_refresh_default, bool, 0444);
+
+static void efivarfs_clean_dentry(struct dentry *dentry)
+{
+ struct dentry *child;
+
+ if (!dentry)
+ return;
+
+ if (d_is_dir(dentry)) {
+ spin_lock(&dentry->d_lock);
+ hlist_for_each_entry(child, &dentry->d_children, d_sib) {
+ if (child)
+ efivarfs_clean_dentry(child);
+ }
+ spin_unlock(&dentry->d_lock);
+ } else {
+ d_invalidate(dentry);
+ }
+}
+
+static int efivarfs_refresh(struct fs_context *fc)
+{
+ struct efivarfs_fs_info *sbi = fc->s_fs_info;
+
+ if (!efivarfs_refresh_default)
+ return 0;
+
+ if (!fc->root)
+ return -EINVAL;
+
+ efivarfs_clean_dentry(fc->root);
+ efivar_init(efivarfs_callback, fc->root->d_sb, &sbi->efivarfs_list);
+
+ return 0;
+}
+
static int efivarfs_parse_param(struct fs_context *fc, struct fs_parameter *param)
{
struct efivarfs_fs_info *sbi = fc->s_fs_info;
@@ -351,7 +389,7 @@ static int efivarfs_reconfigure(struct fs_context *fc)
return -EINVAL;
}
- return 0;
+ return efivarfs_refresh(fc);
}
static const struct fs_context_operations efivarfs_context_ops = {
--
2.45.2
