[RFC v2 23/83] Save allocator to pmem in put_super.

Andiry Xu
2018-03-10T18:39:36Z

We allocate log pages and append free range node to the log of the reserved blocknode inode.
We can recover the allocator status by reading the log upon normal recovery.

Signed-off-by: Andiry Xu <jix024@cs.ucsd.edu>
---
fs/nova/bbuild.c | 114 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
fs/nova/bbuild.h | 1 +
fs/nova/inode.h | 13 +++++++
fs/nova/nova.h | 7 ++++
fs/nova/super.c | 2 +
5 files changed, 137 insertions(+)

diff --git a/fs/nova/bbuild.c b/fs/nova/bbuild.c
index 8bc0545..12a2f11 100644
--- a/fs/nova/bbuild.c
+++ b/fs/nova/bbuild.c
@@ -51,3 +51,117 @@ void nova_init_header(struct super_block *sb,
init_rwsem(&sih->i_sem);
}

+static u64 nova_append_range_node_entry(struct super_block *sb,
+ struct nova_range_node *curr, u64 tail, unsigned long cpuid)
+{
+ u64 curr_p;
+ size_t size = sizeof(struct nova_range_node_lowhigh);
+ struct nova_range_node_lowhigh *entry;
+
+ curr_p = tail;
+
+ if (curr_p == 0 || (is_last_entry(curr_p, size) &&
+ next_log_page(sb, curr_p) == 0)) {
+ nova_dbg("%s: inode log reaches end?\n", __func__);
+ goto out;
+ }
+
+ if (is_last_entry(curr_p, size))
+ curr_p = next_log_page(sb, curr_p);
+
+ entry = (struct nova_range_node_lowhigh *)nova_get_block(sb, curr_p);
+ entry->range_low = cpu_to_le64(curr->range_low);
+ if (cpuid)
+ entry->range_low |= cpu_to_le64(cpuid << 56);
+ entry->range_high = cpu_to_le64(curr->range_high);
+ nova_dbgv("append entry block low 0x%lx, high 0x%lx\n",
+ curr->range_low, curr->range_high);
+
+ nova_flush_buffer(entry, sizeof(struct nova_range_node_lowhigh), 0);
+out:
+ return curr_p;
+}
+
+static u64 nova_save_range_nodes_to_log(struct super_block *sb,
+ struct rb_root *tree, u64 temp_tail, unsigned long cpuid)
+{
+ struct nova_range_node *curr;
+ struct rb_node *temp;
+ size_t size = sizeof(struct nova_range_node_lowhigh);
+ u64 curr_entry = 0;
+
+ /* Save in increasing order */
+ temp = rb_first(tree);
+ while (temp) {
+ curr = container_of(temp, struct nova_range_node, node);
+ curr_entry = nova_append_range_node_entry(sb, curr,
+ temp_tail, cpuid);
+ temp_tail = curr_entry + size;
+ temp = rb_next(temp);
+ rb_erase(&curr->node, tree);
+ nova_free_range_node(curr);
+ }
+
+ return temp_tail;
+}
+
+static u64 nova_save_free_list_blocknodes(struct super_block *sb, int cpu,
+ u64 temp_tail)
+{
+ struct free_list *free_list;
+
+ free_list = nova_get_free_list(sb, cpu);
+ temp_tail = nova_save_range_nodes_to_log(sb,
+ &free_list->block_free_tree, temp_tail, 0);
+ return temp_tail;
+}
+
+void nova_save_blocknode_mappings_to_log(struct super_block *sb)
+{
+ struct nova_inode *pi = nova_get_inode_by_ino(sb, NOVA_BLOCKNODE_INO);
+ struct nova_inode_info_header sih;
+ struct nova_sb_info *sbi = NOVA_SB(sb);
+ struct free_list *free_list;
+ unsigned long num_blocknode = 0;
+ unsigned long num_pages;
+ int allocated;
+ u64 new_block = 0;
+ u64 temp_tail;
+ int i;
+
+ sih.ino = NOVA_BLOCKNODE_INO;
+ sih.i_blk_type = NOVA_DEFAULT_BLOCK_TYPE;
+
+ /* Allocate log pages before save blocknode mappings */
+ for (i = 0; i < sbi->cpus; i++) {
+ free_list = nova_get_free_list(sb, i);
+ num_blocknode += free_list->num_blocknode;
+ nova_dbgv("%s: free list %d: %lu nodes\n", __func__,
+ i, free_list->num_blocknode);
+ }
+
+ num_pages = num_blocknode / RANGENODE_PER_PAGE;
+ if (num_blocknode % RANGENODE_PER_PAGE)
+ num_pages++;
+
+ allocated = nova_allocate_inode_log_pages(sb, &sih, num_pages,
+ &new_block, ANY_CPU, 0);
+ if (allocated != num_pages) {
+ nova_dbg("Error saving blocknode mappings: %d\n", allocated);
+ return;
+ }
+
+ temp_tail = new_block;
+ for (i = 0; i < sbi->cpus; i++)
+ temp_tail = nova_save_free_list_blocknodes(sb, i, temp_tail);
+
+ /* Finally update log head and tail */
+ pi->log_head = new_block;
+ nova_update_tail(pi, temp_tail);
+ nova_flush_buffer(&pi->log_head, CACHELINE_SIZE, 0);
+
+ nova_dbg("%s: %lu blocknodes, %lu log pages, pi head 0x%llx, tail 0x%llx\n",
+ __func__, num_blocknode, num_pages,
+ pi->log_head, pi->log_tail);
+}
+
diff --git a/fs/nova/bbuild.h b/fs/nova/bbuild.h
index 162a832..59cc379 100644
--- a/fs/nova/bbuild.h
+++ b/fs/nova/bbuild.h
@@ -3,5 +3,6 @@

void nova_init_header(struct super_block *sb,
struct nova_inode_info_header *sih, u16 i_mode);
+void nova_save_blocknode_mappings_to_log(struct super_block *sb);

#endif
diff --git a/fs/nova/inode.h b/fs/nova/inode.h
index dbd5256..0594ef3 100644
--- a/fs/nova/inode.h
+++ b/fs/nova/inode.h
@@ -123,6 +123,19 @@ static inline void sih_unlock_shared(struct nova_inode_info_header *header)
up_read(&header->i_sem);
}

+static inline void nova_update_tail(struct nova_inode *pi, u64 new_tail)
+{
+ timing_t update_time;
+
+ NOVA_START_TIMING(update_tail_t, update_time);
+
+ PERSISTENT_BARRIER();
+ pi->log_tail = new_tail;
+ nova_flush_buffer(&pi->log_tail, CACHELINE_SIZE, 1);
+
+ NOVA_END_TIMING(update_tail_t, update_time);
+}
+
static inline unsigned int
nova_inode_blk_shift(struct nova_inode_info_header *sih)
{
diff --git a/fs/nova/nova.h b/fs/nova/nova.h
index f5b4ec8..aa88d9f 100644
--- a/fs/nova/nova.h
+++ b/fs/nova/nova.h
@@ -303,6 +303,13 @@ static inline u64 nova_get_epoch_id(struct super_block *sb)
#include "inode.h"
#include "log.h"

+struct nova_range_node_lowhigh {
+ __le64 range_low;
+ __le64 range_high;
+};
+
+#define RANGENODE_PER_PAGE 254
+
/* A node in the RB tree representing a range of pages */
struct nova_range_node {
struct rb_node node;
diff --git a/fs/nova/super.c b/fs/nova/super.c
index 3500d19..7ee3f66 100644
--- a/fs/nova/super.c
+++ b/fs/nova/super.c
@@ -705,6 +705,8 @@ static void nova_put_super(struct super_block *sb)
struct nova_sb_info *sbi = NOVA_SB(sb);

if (sbi->virt_addr) {
+ /* Save everything before blocknode mapping! */
+ nova_save_blocknode_mappings_to_log(sb);
sbi->virt_addr = NULL;
}

--
2.7.4