From a95ba66ac1457b76fe472c8e092ab1006271f16c Mon Sep 17 00:00:00 2001 From: Jaegeuk Kim Date: Fri, 6 Nov 2020 13:22:05 -0800 Subject: [PATCH] f2fs: avoid race condition for shrinker count Light reported sometimes shinker gets nat_cnt < dirty_nat_cnt resulting in wrong do_shinker work. Let's avoid to return insane overflowed value by adding single tracking value. Reported-by: Light Hsieh Reviewed-by: Chao Yu Signed-off-by: Jaegeuk Kim --- fs/f2fs/checkpoint.c | 2 +- fs/f2fs/debug.c | 11 ++++++----- fs/f2fs/f2fs.h | 10 ++++++++-- fs/f2fs/node.c | 29 ++++++++++++++++++----------- fs/f2fs/node.h | 4 ++-- fs/f2fs/shrinker.c | 4 +--- 6 files changed, 36 insertions(+), 24 deletions(-) diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c index 14ba151..617d0f6 100644 --- a/fs/f2fs/checkpoint.c +++ b/fs/f2fs/checkpoint.c @@ -1619,7 +1619,7 @@ int f2fs_write_checkpoint(struct f2fs_sb_info *sbi, struct cp_control *cpc) goto out; } - if (NM_I(sbi)->dirty_nat_cnt == 0 && + if (NM_I(sbi)->nat_cnt[DIRTY_NAT] == 0 && SIT_I(sbi)->dirty_sentries == 0 && prefree_segments(sbi) == 0) { f2fs_flush_sit_entries(sbi, cpc); diff --git a/fs/f2fs/debug.c b/fs/f2fs/debug.c index a8357fd..197c914 100644 --- a/fs/f2fs/debug.c +++ b/fs/f2fs/debug.c @@ -145,8 +145,8 @@ static void update_general_status(struct f2fs_sb_info *sbi) si->node_pages = NODE_MAPPING(sbi)->nrpages; if (sbi->meta_inode) si->meta_pages = META_MAPPING(sbi)->nrpages; - si->nats = NM_I(sbi)->nat_cnt; - si->dirty_nats = NM_I(sbi)->dirty_nat_cnt; + si->nats = NM_I(sbi)->nat_cnt[TOTAL_NAT]; + si->dirty_nats = NM_I(sbi)->nat_cnt[DIRTY_NAT]; si->sits = MAIN_SEGS(sbi); si->dirty_sits = SIT_I(sbi)->dirty_sentries; si->free_nids = NM_I(sbi)->nid_cnt[FREE_NID]; @@ -278,9 +278,10 @@ get_cache: si->cache_mem += (NM_I(sbi)->nid_cnt[FREE_NID] + NM_I(sbi)->nid_cnt[PREALLOC_NID]) * sizeof(struct free_nid); - si->cache_mem += NM_I(sbi)->nat_cnt * sizeof(struct nat_entry); - si->cache_mem += NM_I(sbi)->dirty_nat_cnt * - sizeof(struct nat_entry_set); + si->cache_mem += NM_I(sbi)->nat_cnt[TOTAL_NAT] * + sizeof(struct nat_entry); + si->cache_mem += NM_I(sbi)->nat_cnt[DIRTY_NAT] * + sizeof(struct nat_entry_set); si->cache_mem += si->inmem_pages * sizeof(struct inmem_pages); for (i = 0; i < MAX_INO_ENTRY; i++) si->cache_mem += sbi->im[i].ino_num * sizeof(struct ino_entry); diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h index 7c02b6d..36090cd 100644 --- a/fs/f2fs/f2fs.h +++ b/fs/f2fs/f2fs.h @@ -820,6 +820,13 @@ enum nid_state { MAX_NID_STATE, }; +enum nat_state { + TOTAL_NAT, + DIRTY_NAT, + RECLAIMABLE_NAT, + MAX_NAT_STATE, +}; + struct f2fs_nm_info { block_t nat_blkaddr; /* base disk address of NAT */ nid_t max_nid; /* maximum possible node ids */ @@ -835,8 +842,7 @@ struct f2fs_nm_info { struct rw_semaphore nat_tree_lock; /* protect nat_tree_lock */ struct list_head nat_entries; /* cached nat entry list (clean) */ spinlock_t nat_list_lock; /* protect clean nat entry list */ - unsigned int nat_cnt; /* the # of cached nat entries */ - unsigned int dirty_nat_cnt; /* total num of nat entries in set */ + unsigned int nat_cnt[MAX_NAT_STATE]; /* the # of cached nat entries */ unsigned int nat_blocks; /* # of nat blocks */ /* free node ids management */ diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c index 42394de..e65d732 100644 --- a/fs/f2fs/node.c +++ b/fs/f2fs/node.c @@ -62,8 +62,8 @@ bool f2fs_available_free_memory(struct f2fs_sb_info *sbi, int type) sizeof(struct free_nid)) >> PAGE_SHIFT; res = mem_size < ((avail_ram * nm_i->ram_thresh / 100) >> 2); } else if (type == NAT_ENTRIES) { - mem_size = (nm_i->nat_cnt * sizeof(struct nat_entry)) >> - PAGE_SHIFT; + mem_size = (nm_i->nat_cnt[TOTAL_NAT] * + sizeof(struct nat_entry)) >> PAGE_SHIFT; res = mem_size < ((avail_ram * nm_i->ram_thresh / 100) >> 2); if (excess_cached_nats(sbi)) res = false; @@ -177,7 +177,8 @@ static struct nat_entry *__init_nat_entry(struct f2fs_nm_info *nm_i, list_add_tail(&ne->list, &nm_i->nat_entries); spin_unlock(&nm_i->nat_list_lock); - nm_i->nat_cnt++; + nm_i->nat_cnt[TOTAL_NAT]++; + nm_i->nat_cnt[RECLAIMABLE_NAT]++; return ne; } @@ -207,7 +208,8 @@ static unsigned int __gang_lookup_nat_cache(struct f2fs_nm_info *nm_i, static void __del_from_nat_cache(struct f2fs_nm_info *nm_i, struct nat_entry *e) { radix_tree_delete(&nm_i->nat_root, nat_get_nid(e)); - nm_i->nat_cnt--; + nm_i->nat_cnt[TOTAL_NAT]--; + nm_i->nat_cnt[RECLAIMABLE_NAT]--; __free_nat_entry(e); } @@ -253,7 +255,8 @@ static void __set_nat_cache_dirty(struct f2fs_nm_info *nm_i, if (get_nat_flag(ne, IS_DIRTY)) goto refresh_list; - nm_i->dirty_nat_cnt++; + nm_i->nat_cnt[DIRTY_NAT]++; + nm_i->nat_cnt[RECLAIMABLE_NAT]--; set_nat_flag(ne, IS_DIRTY, true); refresh_list: spin_lock(&nm_i->nat_list_lock); @@ -273,7 +276,8 @@ static void __clear_nat_cache_dirty(struct f2fs_nm_info *nm_i, set_nat_flag(ne, IS_DIRTY, false); set->entry_cnt--; - nm_i->dirty_nat_cnt--; + nm_i->nat_cnt[DIRTY_NAT]--; + nm_i->nat_cnt[RECLAIMABLE_NAT]++; } static unsigned int __gang_lookup_nat_set(struct f2fs_nm_info *nm_i, @@ -2944,14 +2948,17 @@ int f2fs_flush_nat_entries(struct f2fs_sb_info *sbi, struct cp_control *cpc) LIST_HEAD(sets); int err = 0; - /* during unmount, let's flush nat_bits before checking dirty_nat_cnt */ + /* + * during unmount, let's flush nat_bits before checking + * nat_cnt[DIRTY_NAT]. + */ if (enabled_nat_bits(sbi, cpc)) { down_write(&nm_i->nat_tree_lock); remove_nats_in_journal(sbi); up_write(&nm_i->nat_tree_lock); } - if (!nm_i->dirty_nat_cnt) + if (!nm_i->nat_cnt[DIRTY_NAT]) return 0; down_write(&nm_i->nat_tree_lock); @@ -2962,7 +2969,8 @@ int f2fs_flush_nat_entries(struct f2fs_sb_info *sbi, struct cp_control *cpc) * into nat entry set. */ if (enabled_nat_bits(sbi, cpc) || - !__has_cursum_space(journal, nm_i->dirty_nat_cnt, NAT_JOURNAL)) + !__has_cursum_space(journal, + nm_i->nat_cnt[DIRTY_NAT], NAT_JOURNAL)) remove_nats_in_journal(sbi); while ((found = __gang_lookup_nat_set(nm_i, @@ -3086,7 +3094,6 @@ static int init_node_manager(struct f2fs_sb_info *sbi) F2FS_RESERVED_NODE_NUM; nm_i->nid_cnt[FREE_NID] = 0; nm_i->nid_cnt[PREALLOC_NID] = 0; - nm_i->nat_cnt = 0; nm_i->ram_thresh = DEF_RAM_THRESHOLD; nm_i->ra_nid_pages = DEF_RA_NID_PAGES; nm_i->dirty_nats_ratio = DEF_DIRTY_NAT_RATIO_THRESHOLD; @@ -3220,7 +3227,7 @@ void f2fs_destroy_node_manager(struct f2fs_sb_info *sbi) __del_from_nat_cache(nm_i, natvec[idx]); } } - f2fs_bug_on(sbi, nm_i->nat_cnt); + f2fs_bug_on(sbi, nm_i->nat_cnt[TOTAL_NAT]); /* destroy nat set cache */ nid = 0; diff --git a/fs/f2fs/node.h b/fs/f2fs/node.h index 69e5859..f84541b 100644 --- a/fs/f2fs/node.h +++ b/fs/f2fs/node.h @@ -126,13 +126,13 @@ static inline void raw_nat_from_node_info(struct f2fs_nat_entry *raw_ne, static inline bool excess_dirty_nats(struct f2fs_sb_info *sbi) { - return NM_I(sbi)->dirty_nat_cnt >= NM_I(sbi)->max_nid * + return NM_I(sbi)->nat_cnt[DIRTY_NAT] >= NM_I(sbi)->max_nid * NM_I(sbi)->dirty_nats_ratio / 100; } static inline bool excess_cached_nats(struct f2fs_sb_info *sbi) { - return NM_I(sbi)->nat_cnt >= DEF_NAT_CACHE_THRESHOLD; + return NM_I(sbi)->nat_cnt[TOTAL_NAT] >= DEF_NAT_CACHE_THRESHOLD; } static inline bool excess_dirty_nodes(struct f2fs_sb_info *sbi) diff --git a/fs/f2fs/shrinker.c b/fs/f2fs/shrinker.c index d66de599..dd3c3c7 100644 --- a/fs/f2fs/shrinker.c +++ b/fs/f2fs/shrinker.c @@ -18,9 +18,7 @@ static unsigned int shrinker_run_no; static unsigned long __count_nat_entries(struct f2fs_sb_info *sbi) { - long count = NM_I(sbi)->nat_cnt - NM_I(sbi)->dirty_nat_cnt; - - return count > 0 ? count : 0; + return NM_I(sbi)->nat_cnt[RECLAIMABLE_NAT]; } static unsigned long __count_free_nids(struct f2fs_sb_info *sbi) -- 2.7.4