Allocate space for md-raid

src/engine/strat_engine/backstore/blockdev/v2.rs

@@ -51,6 +51,14 @@ pub fn integrity_meta_space(total_space: Sectors) -> Sectors {
         + Bytes::from((*total_space * 32u64 + 4095) & !4096).sectors()
 }
 
+/// Return the amount of space required for integrity for a device of the given size.
+///
+/// This is a slight overestimation for the sake of simplicity. The maximum metadata size is used
+/// to leave adequate room for any sized device's metadata.
+pub fn raid_meta_space() -> Sectors {
+    Bytes::from(129 * IEC::Mi).sectors()
+}
+
 #[derive(Debug)]
 pub struct StratBlockDev {
     dev: Device,
@@ -174,6 +182,14 @@ impl StratBlockDev {
         Ok(blkdev_size(&File::open(physical_path)?)?.sectors())
     }
 
+    /// Allocate room for RAID metadata from the back of the device.
+    pub fn alloc_raid_meta(&mut self, size: Sectors) {
+        let segs = self.used.alloc_front(size);
+        for (start, len) in segs.iter() {
+            self.raid_meta_allocs.push((*start, *len));
+        }
+    }
+
     /// Allocate room for integrity metadata from the back of the device.
     pub fn alloc_int_meta_back(&mut self, size: Sectors) {
         let segs = self.used.alloc_back(size);
@@ -240,6 +256,7 @@ impl InternalBlockDev for StratBlockDev {
     fn metadata_size(&self) -> Sectors {
         self.bda.extended_size().sectors()
             + self.integrity_meta_allocs.iter().map(|(_, len)| *len).sum()
+            + self.raid_meta_allocs.iter().map(|(_, len)| *len).sum()
     }
 
     fn max_stratis_metadata_size(&self) -> MDADataSize {

src/engine/strat_engine/backstore/data_tier.rs

@@ -13,7 +13,11 @@ use crate::{
     engine::{
         strat_engine::{
             backstore::{
-                blockdev::{v1, v2, InternalBlockDev},
+                blockdev::{
+                    v1,
+                    v2::{self, integrity_meta_space, raid_meta_space},
+                    InternalBlockDev,
+                },
                 blockdevmgr::BlockDevMgr,
                 devices::UnownedDevices,
                 shared::{metadata_to_segment, AllocatedAbove, BlkDevSegment, BlockDevPartition},
@@ -28,8 +32,6 @@ use crate::{
     stratis::StratisResult,
 };
 
-use super::blockdev::v2::integrity_meta_space;
-
 /// Handles the lowest level, base layer of this tier.
 #[derive(Debug)]
 pub struct DataTier<B> {
@@ -105,12 +107,13 @@ impl DataTier<v2::StratBlockDev> {
     /// WARNING: metadata changing event
     pub fn new(mut block_mgr: BlockDevMgr<v2::StratBlockDev>) -> DataTier<v2::StratBlockDev> {
         for (_, bd) in block_mgr.blockdevs_mut() {
+            bd.alloc_raid_meta(raid_meta_space());
             bd.alloc_int_meta_back(integrity_meta_space(
                 // NOTE: Subtracting metadata size works here because the only metadata currently
                 // recorded in a newly created block device is the BDA. If this becomes untrue in
                 // the future, this code will no longer work.
                 bd.total_size().sectors() - bd.metadata_size(),
-            ))
+            ));
         }
         DataTier {
             block_mgr,