Re: [PATCH V2] f2fs: introduce free nid bitmap
From: Chao Yu
Date: Sun Feb 26 2017 - 22:12:12 EST
On 2017/2/26 3:02, Jaegeuk Kim wrote:
> On 02/25, Chao Yu wrote:
>> Hi Jaegeuk,
>>
>> I added below diff code into this patch in order to fix incorrectly nid status
>> updating to reduce large latency of generic/251 in fstest, could you help to
>> review code below?
>
> Understand the problem, and how about this?
>
> diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
> index 52db02396878..83b305689913 100644
> --- a/fs/f2fs/node.c
> +++ b/fs/f2fs/node.c
> @@ -1765,7 +1765,7 @@ static void __remove_nid_from_list(struct f2fs_sb_info *sbi,
> radix_tree_delete(&nm_i->free_nid_root, i->nid);
> }
>
> -static int add_free_nid(struct f2fs_sb_info *sbi, nid_t nid, bool build)
> +static bool add_free_nid(struct f2fs_sb_info *sbi, nid_t nid, bool build)
> {
> struct f2fs_nm_info *nm_i = NM_I(sbi);
> struct free_nid *i;
> @@ -1774,14 +1774,14 @@ static int add_free_nid(struct f2fs_sb_info *sbi, nid_t nid, bool build)
>
> /* 0 nid should not be used */
> if (unlikely(nid == 0))
> - return 0;
> + return false;
>
> if (build) {
> /* do not add allocated nids */
> ne = __lookup_nat_cache(nm_i, nid);
> if (ne && (!get_nat_flag(ne, IS_CHECKPOINTED) ||
> nat_get_blkaddr(ne) != NULL_ADDR))
> - return 0;
> + return false;
> }
>
> i = f2fs_kmem_cache_alloc(free_nid_slab, GFP_NOFS);
> @@ -1790,7 +1790,7 @@ static int add_free_nid(struct f2fs_sb_info *sbi, nid_t nid, bool build)
>
> if (radix_tree_preload(GFP_NOFS)) {
> kmem_cache_free(free_nid_slab, i);
> - return 0;
> + return false;
If there is no memory, actually current free nid is still available, we need to
return true (or other value -1?), then caller can set free_nid_bitmap correctly.
> }
>
> spin_lock(&nm_i->nid_list_lock);
> @@ -1799,9 +1799,9 @@ static int add_free_nid(struct f2fs_sb_info *sbi, nid_t nid, bool build)
> radix_tree_preload_end();
> if (err) {
> kmem_cache_free(free_nid_slab, i);
> - return 0;
> + return false;
ditto.
Thanks,
> }
> - return 1;
> + return true;
> }
>
> static void remove_free_nid(struct f2fs_sb_info *sbi, nid_t nid)
> @@ -1851,6 +1851,7 @@ static void scan_nat_page(struct f2fs_sb_info *sbi,
> i = start_nid % NAT_ENTRY_PER_BLOCK;
>
> for (; i < NAT_ENTRY_PER_BLOCK; i++, start_nid++) {
> + bool freed = false;
>
> if (unlikely(start_nid >= nm_i->max_nid))
> break;
> @@ -1858,8 +1859,8 @@ static void scan_nat_page(struct f2fs_sb_info *sbi,
> blk_addr = le32_to_cpu(nat_blk->entries[i].block_addr);
> f2fs_bug_on(sbi, blk_addr == NEW_ADDR);
> if (blk_addr == NULL_ADDR)
> - add_free_nid(sbi, start_nid, true);
> - update_free_nid_bitmap(sbi, start_nid, blk_addr == NULL_ADDR);
> + freed = add_free_nid(sbi, start_nid, true);
> + update_free_nid_bitmap(sbi, start_nid, freed);
> }
> }
>
>