bdi: allow block devices to say that they require stable page writes

[mirror_ubuntu-artful-kernel.git] / include / linux / backing-dev.h

diff --git a/include/linux/backing-dev.h b/include/linux/backing-dev.h
index 12731a19ef060792b5500c3731551b636c437fe8..350459910fe138a3d47573a07e8b125c62f36564 100644 (file)
--- a/include/linux/backing-dev.h
+++ b/include/linux/backing-dev.h
@@ -254,6 +254,7 @@ int bdi_set_max_ratio(struct backing_dev_info *bdi, unsigned int max_ratio);
 #define BDI_CAP_EXEC_MAP       0x00000040
 #define BDI_CAP_NO_ACCT_WB     0x00000080
 #define BDI_CAP_SWAP_BACKED    0x00000100
+#define BDI_CAP_STABLE_WRITES  0x00000200
 
 #define BDI_CAP_VMFLAGS \
        (BDI_CAP_READ_MAP | BDI_CAP_WRITE_MAP | BDI_CAP_EXEC_MAP)
@@ -308,6 +309,11 @@ long wait_iff_congested(struct zone *zone, int sync, long timeout);
 int pdflush_proc_obsolete(struct ctl_table *table, int write,
                void __user *buffer, size_t *lenp, loff_t *ppos);
 
+static inline bool bdi_cap_stable_pages_required(struct backing_dev_info *bdi)
+{
+       return bdi->capabilities & BDI_CAP_STABLE_WRITES;
+}
+
 static inline bool bdi_cap_writeback_dirty(struct backing_dev_info *bdi)
 {
        return !(bdi->capabilities & BDI_CAP_NO_WRITEBACK);