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Subject[RFC v2 80/83] Failure recovery: bitmap operations.
Date
From: Andiry Xu <jix024@cs.ucsd.edu>

Upon system failure, NOVA needs to scan all the inode logs
to rebuild the allocator. During the scanning, NOVA stores allocated
log/data pages in a bitmap, and uses the bitmap to rebuild the allocator
once scan finishes.

Signed-off-by: Andiry Xu <jix024@cs.ucsd.edu>
---
fs/nova/bbuild.c | 252 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
fs/nova/bbuild.h | 18 ++++
2 files changed, 270 insertions(+)

diff --git a/fs/nova/bbuild.c b/fs/nova/bbuild.c
index ca51dca..35c661a 100644
--- a/fs/nova/bbuild.c
+++ b/fs/nova/bbuild.c
@@ -414,6 +414,258 @@ void nova_save_blocknode_mappings_to_log(struct super_block *sb)
pi->log_head, pi->log_tail);
}

+/************************** Bitmap operations ****************************/
+
+static inline void set_scan_bm(unsigned long bit,
+ struct single_scan_bm *scan_bm)
+{
+ set_bit(bit, scan_bm->bitmap);
+}
+
+inline void set_bm(unsigned long bit, struct scan_bitmap *bm,
+ enum bm_type type)
+{
+ switch (type) {
+ case BM_4K:
+ set_scan_bm(bit, &bm->scan_bm_4K);
+ break;
+ case BM_2M:
+ set_scan_bm(bit, &bm->scan_bm_2M);
+ break;
+ case BM_1G:
+ set_scan_bm(bit, &bm->scan_bm_1G);
+ break;
+ default:
+ break;
+ }
+}
+
+static int nova_insert_blocknode_map(struct super_block *sb,
+ int cpuid, unsigned long low, unsigned long high)
+{
+ struct nova_sb_info *sbi = NOVA_SB(sb);
+ struct free_list *free_list;
+ struct rb_root *tree;
+ struct nova_range_node *blknode = NULL;
+ unsigned long num_blocks = 0;
+ int ret;
+
+ num_blocks = high - low + 1;
+ nova_dbgv("%s: cpu %d, low %lu, high %lu, num %lu\n",
+ __func__, cpuid, low, high, num_blocks);
+ free_list = nova_get_free_list(sb, cpuid);
+ tree = &(free_list->block_free_tree);
+
+ blknode = nova_alloc_blocknode(sb);
+ if (blknode == NULL)
+ return -ENOMEM;
+ blknode->range_low = low;
+ blknode->range_high = high;
+ ret = nova_insert_blocktree(sbi, tree, blknode);
+ if (ret) {
+ nova_err(sb, "%s failed\n", __func__);
+ nova_free_blocknode(sb, blknode);
+ goto out;
+ }
+ if (!free_list->first_node)
+ free_list->first_node = blknode;
+ free_list->last_node = blknode;
+ free_list->num_blocknode++;
+ free_list->num_free_blocks += num_blocks;
+out:
+ return ret;
+}
+
+static int __nova_build_blocknode_map(struct super_block *sb,
+ unsigned long *bitmap, unsigned long bsize, unsigned long scale)
+{
+ struct nova_sb_info *sbi = NOVA_SB(sb);
+ struct free_list *free_list;
+ unsigned long next = 0;
+ unsigned long low = 0;
+ unsigned long start, end;
+ int cpuid = 0;
+
+ free_list = nova_get_free_list(sb, cpuid);
+ start = free_list->block_start;
+ end = free_list->block_end + 1;
+ while (1) {
+ next = find_next_zero_bit(bitmap, end, start);
+ if (next == bsize)
+ break;
+ if (next == end) {
+ if (cpuid == sbi->cpus - 1)
+ break;
+
+ cpuid++;
+ free_list = nova_get_free_list(sb, cpuid);
+ start = free_list->block_start;
+ end = free_list->block_end + 1;
+ continue;
+ }
+
+ low = next;
+ next = find_next_bit(bitmap, end, next);
+ if (nova_insert_blocknode_map(sb, cpuid,
+ low << scale, (next << scale) - 1)) {
+ nova_dbg("Error: could not insert %lu - %lu\n",
+ low << scale, ((next << scale) - 1));
+ }
+ start = next;
+ if (next == bsize)
+ break;
+ if (next == end) {
+ if (cpuid == sbi->cpus - 1)
+ break;
+
+ cpuid++;
+ free_list = nova_get_free_list(sb, cpuid);
+ start = free_list->block_start;
+ end = free_list->block_end + 1;
+ }
+ }
+ return 0;
+}
+
+static void nova_update_4K_map(struct super_block *sb,
+ struct scan_bitmap *bm, unsigned long *bitmap,
+ unsigned long bsize, unsigned long scale)
+{
+ unsigned long next = 0;
+ unsigned long low = 0;
+ int i;
+
+ while (1) {
+ next = find_next_bit(bitmap, bsize, next);
+ if (next == bsize)
+ break;
+ low = next;
+ next = find_next_zero_bit(bitmap, bsize, next);
+ for (i = (low << scale); i < (next << scale); i++)
+ set_bm(i, bm, BM_4K);
+ if (next == bsize)
+ break;
+ }
+}
+
+struct scan_bitmap *global_bm[MAX_CPUS];
+
+static int nova_build_blocknode_map(struct super_block *sb,
+ unsigned long initsize)
+{
+ struct nova_sb_info *sbi = NOVA_SB(sb);
+ struct scan_bitmap *bm;
+ struct scan_bitmap *final_bm;
+ unsigned long *src, *dst;
+ int i, j;
+ int num;
+ int ret;
+
+ final_bm = kzalloc(sizeof(struct scan_bitmap), GFP_KERNEL);
+ if (!final_bm)
+ return -ENOMEM;
+
+ final_bm->scan_bm_4K.bitmap_size =
+ (initsize >> (PAGE_SHIFT + 0x3));
+
+ /* Alloc memory to hold the block alloc bitmap */
+ final_bm->scan_bm_4K.bitmap = kzalloc(final_bm->scan_bm_4K.bitmap_size,
+ GFP_KERNEL);
+
+ if (!final_bm->scan_bm_4K.bitmap) {
+ kfree(final_bm);
+ return -ENOMEM;
+ }
+
+ /*
+ * We are using free lists. Set 2M and 1G blocks in 4K map,
+ * and use 4K map to rebuild block map.
+ */
+ for (i = 0; i < sbi->cpus; i++) {
+ bm = global_bm[i];
+ nova_update_4K_map(sb, bm, bm->scan_bm_2M.bitmap,
+ bm->scan_bm_2M.bitmap_size * 8, PAGE_SHIFT_2M - 12);
+ nova_update_4K_map(sb, bm, bm->scan_bm_1G.bitmap,
+ bm->scan_bm_1G.bitmap_size * 8, PAGE_SHIFT_1G - 12);
+ }
+
+ /* Merge per-CPU bms to the final single bm */
+ num = final_bm->scan_bm_4K.bitmap_size / sizeof(unsigned long);
+ if (final_bm->scan_bm_4K.bitmap_size % sizeof(unsigned long))
+ num++;
+
+ for (i = 0; i < sbi->cpus; i++) {
+ bm = global_bm[i];
+ src = (unsigned long *)bm->scan_bm_4K.bitmap;
+ dst = (unsigned long *)final_bm->scan_bm_4K.bitmap;
+
+ for (j = 0; j < num; j++)
+ dst[j] |= src[j];
+ }
+
+ ret = __nova_build_blocknode_map(sb, final_bm->scan_bm_4K.bitmap,
+ final_bm->scan_bm_4K.bitmap_size * 8, PAGE_SHIFT - 12);
+
+ kfree(final_bm->scan_bm_4K.bitmap);
+ kfree(final_bm);
+
+ return ret;
+}
+
+static void free_bm(struct super_block *sb)
+{
+ struct nova_sb_info *sbi = NOVA_SB(sb);
+ struct scan_bitmap *bm;
+ int i;
+
+ for (i = 0; i < sbi->cpus; i++) {
+ bm = global_bm[i];
+ if (bm) {
+ kfree(bm->scan_bm_4K.bitmap);
+ kfree(bm->scan_bm_2M.bitmap);
+ kfree(bm->scan_bm_1G.bitmap);
+ kfree(bm);
+ }
+ }
+}
+
+static int alloc_bm(struct super_block *sb, unsigned long initsize)
+{
+ struct nova_sb_info *sbi = NOVA_SB(sb);
+ struct scan_bitmap *bm;
+ int i;
+
+ for (i = 0; i < sbi->cpus; i++) {
+ bm = kzalloc(sizeof(struct scan_bitmap), GFP_KERNEL);
+ if (!bm)
+ return -ENOMEM;
+
+ global_bm[i] = bm;
+
+ bm->scan_bm_4K.bitmap_size =
+ (initsize >> (PAGE_SHIFT + 0x3));
+ bm->scan_bm_2M.bitmap_size =
+ (initsize >> (PAGE_SHIFT_2M + 0x3));
+ bm->scan_bm_1G.bitmap_size =
+ (initsize >> (PAGE_SHIFT_1G + 0x3));
+
+ /* Alloc memory to hold the block alloc bitmap */
+ bm->scan_bm_4K.bitmap = kzalloc(bm->scan_bm_4K.bitmap_size,
+ GFP_KERNEL);
+ bm->scan_bm_2M.bitmap = kzalloc(bm->scan_bm_2M.bitmap_size,
+ GFP_KERNEL);
+ bm->scan_bm_1G.bitmap = kzalloc(bm->scan_bm_1G.bitmap_size,
+ GFP_KERNEL);
+
+ if (!bm->scan_bm_4K.bitmap || !bm->scan_bm_2M.bitmap ||
+ !bm->scan_bm_1G.bitmap)
+ return -ENOMEM;
+ }
+
+ return 0;
+}
+
+
/*********************** Recovery entrance *************************/

/* Return TRUE if we can do a normal unmount recovery */
diff --git a/fs/nova/bbuild.h b/fs/nova/bbuild.h
index 2c3deb0..b093e05 100644
--- a/fs/nova/bbuild.h
+++ b/fs/nova/bbuild.h
@@ -1,6 +1,24 @@
#ifndef __BBUILD_H
#define __BBUILD_H

+enum bm_type {
+ BM_4K = 0,
+ BM_2M,
+ BM_1G,
+};
+
+struct single_scan_bm {
+ unsigned long bitmap_size;
+ unsigned long *bitmap;
+};
+
+struct scan_bitmap {
+ struct single_scan_bm scan_bm_4K;
+ struct single_scan_bm scan_bm_2M;
+ struct single_scan_bm scan_bm_1G;
+};
+
+
void nova_init_header(struct super_block *sb,
struct nova_inode_info_header *sih, u16 i_mode);
void nova_save_inode_list_to_log(struct super_block *sb);
--
2.7.4
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