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Date: Wed, 1 Mar 2017 17:10:13 +0800
From: Chao Yu <yuchao0@...wei.com>
To: <jaegeuk@...nel.org>
CC: <linux-f2fs-devel@...ts.sourceforge.net>,
<linux-kernel@...r.kernel.org>, <chao@...nel.org>,
Chao Yu <yuchao0@...wei.com>
Subject: [PATCH RFC] f2fs: combine nat_bits and free_nid_bitmap cache
Both nat_bits cache and free_nid_bitmap cache provide same functionality
as a intermediate cache between free nid cache and disk, but with
different granularity of indicating free nid range, and different
persistence policy. nat_bits cache provides better persistence ability,
and free_nid_bitmap provides better granularity.
In this patch we combine advantage of both caches, so finally policy of
the intermediate cache would be:
- init: load free nid status from nat_bits into free_nid_bitmap
- lookup: scan free_nid_bitmap before load NAT blocks
- update: update free_nid_bitmap in real-time
- persistence: udpate and persist nat_bits in checkpoint
Signed-off-by: Chao Yu <yuchao0@...wei.com>
---
fs/f2fs/node.c | 109 +++++++++++++++++++++------------------------------------
1 file changed, 39 insertions(+), 70 deletions(-)
diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
index 1a759d45b7e4..6c027b6833f4 100644
--- a/fs/f2fs/node.c
+++ b/fs/f2fs/node.c
@@ -338,9 +338,6 @@ static void set_node_addr(struct f2fs_sb_info *sbi, struct node_info *ni,
set_nat_flag(e, IS_CHECKPOINTED, false);
__set_nat_cache_dirty(nm_i, e);
- if (enabled_nat_bits(sbi, NULL) && new_blkaddr == NEW_ADDR)
- clear_bit_le(NAT_BLOCK_OFFSET(ni->nid), nm_i->empty_nat_bits);
-
/* update fsync_mark if its inode nat entry is still alive */
if (ni->nid != ni->ino)
e = __lookup_nat_cache(nm_i, ni->ino);
@@ -1920,58 +1917,6 @@ static void scan_free_nid_bits(struct f2fs_sb_info *sbi)
up_read(&nm_i->nat_tree_lock);
}
-static int scan_nat_bits(struct f2fs_sb_info *sbi)
-{
- struct f2fs_nm_info *nm_i = NM_I(sbi);
- struct page *page;
- unsigned int i = 0;
- nid_t nid;
-
- if (!enabled_nat_bits(sbi, NULL))
- return -EAGAIN;
-
- down_read(&nm_i->nat_tree_lock);
-check_empty:
- i = find_next_bit_le(nm_i->empty_nat_bits, nm_i->nat_blocks, i);
- if (i >= nm_i->nat_blocks) {
- i = 0;
- goto check_partial;
- }
-
- for (nid = i * NAT_ENTRY_PER_BLOCK; nid < (i + 1) * NAT_ENTRY_PER_BLOCK;
- nid++) {
- if (unlikely(nid >= nm_i->max_nid))
- break;
- add_free_nid(sbi, nid, true);
- }
-
- if (nm_i->nid_cnt[FREE_NID_LIST] >= MAX_FREE_NIDS)
- goto out;
- i++;
- goto check_empty;
-
-check_partial:
- i = find_next_zero_bit_le(nm_i->full_nat_bits, nm_i->nat_blocks, i);
- if (i >= nm_i->nat_blocks) {
- disable_nat_bits(sbi, true);
- up_read(&nm_i->nat_tree_lock);
- return -EINVAL;
- }
-
- nid = i * NAT_ENTRY_PER_BLOCK;
- page = get_current_nat_page(sbi, nid);
- scan_nat_page(sbi, page, nid);
- f2fs_put_page(page, 1);
-
- if (nm_i->nid_cnt[FREE_NID_LIST] < MAX_FREE_NIDS) {
- i++;
- goto check_partial;
- }
-out:
- up_read(&nm_i->nat_tree_lock);
- return 0;
-}
-
static void __build_free_nids(struct f2fs_sb_info *sbi, bool sync, bool mount)
{
struct f2fs_nm_info *nm_i = NM_I(sbi);
@@ -1993,21 +1938,6 @@ static void __build_free_nids(struct f2fs_sb_info *sbi, bool sync, bool mount)
if (nm_i->nid_cnt[FREE_NID_LIST])
return;
-
- /* try to find free nids with nat_bits */
- if (!scan_nat_bits(sbi) && nm_i->nid_cnt[FREE_NID_LIST])
- return;
- }
-
- /* find next valid candidate */
- if (enabled_nat_bits(sbi, NULL)) {
- int idx = find_next_zero_bit_le(nm_i->full_nat_bits,
- nm_i->nat_blocks, 0);
-
- if (idx >= nm_i->nat_blocks)
- set_sbi_flag(sbi, SBI_NEED_FSCK);
- else
- nid = idx * NAT_ENTRY_PER_BLOCK;
}
/* readahead nat pages to be scanned */
@@ -2590,6 +2520,41 @@ static int __get_nat_bitmaps(struct f2fs_sb_info *sbi)
return 0;
}
+inline void load_free_nid_bitmap(struct f2fs_sb_info *sbi)
+{
+ struct f2fs_nm_info *nm_i = NM_I(sbi);
+ unsigned int i = 0;
+ nid_t nid, last_nid;
+
+ for (i = 0; i < nm_i->nat_blocks; i++) {
+ i = find_next_bit_le(nm_i->empty_nat_bits, nm_i->nat_blocks, i);
+ if (i >= nm_i->nat_blocks)
+ break;
+
+ set_bit_le(i, nm_i->nat_block_bitmap);
+
+ nid = i * NAT_ENTRY_PER_BLOCK;
+ last_nid = (i + 1) * NAT_ENTRY_PER_BLOCK;
+
+ for (; nid < last_nid; nid++)
+ update_free_nid_bitmap(sbi, nid, true, true);
+ }
+
+ for (i = 0; i < nm_i->nat_blocks; i++) {
+ i = find_next_bit_le(nm_i->full_nat_bits, nm_i->nat_blocks, i);
+ if (i >= nm_i->nat_blocks)
+ break;
+
+ set_bit_le(i, nm_i->nat_block_bitmap);
+
+ nid = i * NAT_ENTRY_PER_BLOCK;
+ last_nid = (i + 1) * NAT_ENTRY_PER_BLOCK;
+
+ for (; nid < last_nid; nid++)
+ update_free_nid_bitmap(sbi, nid, false, true);
+ }
+}
+
static int init_node_manager(struct f2fs_sb_info *sbi)
{
struct f2fs_super_block *sb_raw = F2FS_RAW_SUPER(sbi);
@@ -2672,6 +2637,10 @@ int init_free_nid_cache(struct f2fs_sb_info *sbi)
spin_lock_init(&nm_i->free_nid_lock);
+ /* load free nid status from nat_bits table */
+ if (enabled_nat_bits(sbi, NULL))
+ load_free_nid_bitmap(sbi);
+
return 0;
}
--
2.8.2.295.g3f1c1d0
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