add new system file

hc

2024-02-20 102a0743326a03cd1a1202ceda21e175b7d3575c

 kernel/fs/overlayfs/ovl_entry.h
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@@ -31,6 +31,7 @@
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 };
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 struct ovl_layer {
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+	/* ovl_free_fs() relies on @mnt being the first member! */
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 	struct vfsmount *mnt;
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 	/* Trap in ovl inode cache */
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 	struct inode *trap;
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@@ -41,6 +42,14 @@
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 	int fsid;
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 };
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+/*
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+ * ovl_free_fs() relies on @mnt being the first member when unmounting
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+ * the private mounts created for each layer. Let's check both the
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+ * offset and type.
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+ */
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+static_assert(offsetof(struct ovl_layer, mnt) == 0);
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+static_assert(__same_type(typeof_member(struct ovl_layer, mnt), struct vfsmount *));
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+
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 struct ovl_path {
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 	const struct ovl_layer *layer;
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 	struct dentry *dentry;