Hi Jaegeuk, > -----Original Message----- > From: Jaegeuk Kim [mailto:jaegeuk@xxxxxxxxxx] > Sent: Sunday, January 03, 2016 9:26 AM > To: linux-kernel@xxxxxxxxxxxxxxx; linux-fsdevel@xxxxxxxxxxxxxxx; > linux-f2fs-devel@xxxxxxxxxxxxxxxxxxxxx > Cc: Jaegeuk Kim > Subject: [f2fs-dev] [PATCH 2/3] f2fs: cover more area with nat_tree_lock > > There was a subtle bug on nat cache management which incurs wrong nid allocation > or wrong block addresses when try_to_free_nats is triggered heavily. > This patch enlarges the previous coverage of nat_tree_lock to avoid data race. Have you figured out how this happen? I'm curious about this issue, since still I can't reproduce it and find any clue by reviewing code so far. Thanks, > > Signed-off-by: Jaegeuk Kim <jaegeuk@xxxxxxxxxx> > --- > fs/f2fs/node.c | 29 ++++++++++++----------------- > 1 file changed, 12 insertions(+), 17 deletions(-) > > diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c > index 669c44e..4dab09f 100644 > --- a/fs/f2fs/node.c > +++ b/fs/f2fs/node.c > @@ -262,13 +262,11 @@ static void cache_nat_entry(struct f2fs_nm_info *nm_i, nid_t nid, > { > struct nat_entry *e; > > - down_write(&nm_i->nat_tree_lock); > e = __lookup_nat_cache(nm_i, nid); > if (!e) { > e = grab_nat_entry(nm_i, nid); > node_info_from_raw_nat(&e->ni, ne); > } > - up_write(&nm_i->nat_tree_lock); > } > > static void set_node_addr(struct f2fs_sb_info *sbi, struct node_info *ni, > @@ -380,6 +378,8 @@ void get_node_info(struct f2fs_sb_info *sbi, nid_t nid, struct node_info > *ni) > > memset(&ne, 0, sizeof(struct f2fs_nat_entry)); > > + down_write(&nm_i->nat_tree_lock); > + > /* Check current segment summary */ > mutex_lock(&curseg->curseg_mutex); > i = lookup_journal_in_cursum(sum, NAT_JOURNAL, nid, 0); > @@ -400,6 +400,7 @@ void get_node_info(struct f2fs_sb_info *sbi, nid_t nid, struct node_info > *ni) > cache: > /* cache nat entry */ > cache_nat_entry(NM_I(sbi), nid, &ne); > + up_write(&nm_i->nat_tree_lock); > } > > /* > @@ -1459,13 +1460,10 @@ static int add_free_nid(struct f2fs_sb_info *sbi, nid_t nid, bool build) > > if (build) { > /* do not add allocated nids */ > - down_read(&nm_i->nat_tree_lock); > ne = __lookup_nat_cache(nm_i, nid); > - if (ne && > - (!get_nat_flag(ne, IS_CHECKPOINTED) || > + if (ne && (!get_nat_flag(ne, IS_CHECKPOINTED) || > nat_get_blkaddr(ne) != NULL_ADDR)) > allocated = true; > - up_read(&nm_i->nat_tree_lock); > if (allocated) > return 0; > } > @@ -1551,6 +1549,8 @@ static void build_free_nids(struct f2fs_sb_info *sbi) > ra_meta_pages(sbi, NAT_BLOCK_OFFSET(nid), FREE_NID_PAGES, > META_NAT, true); > > + down_read(&nm_i->nat_tree_lock); > + > while (1) { > struct page *page = get_current_nat_page(sbi, nid); > > @@ -1579,6 +1579,7 @@ static void build_free_nids(struct f2fs_sb_info *sbi) > remove_free_nid(nm_i, nid); > } > mutex_unlock(&curseg->curseg_mutex); > + up_read(&nm_i->nat_tree_lock); > > ra_meta_pages(sbi, NAT_BLOCK_OFFSET(nm_i->next_scan_nid), > nm_i->ra_nid_pages, META_NAT, false); > @@ -1861,14 +1862,12 @@ static void remove_nats_in_journal(struct f2fs_sb_info *sbi) > > raw_ne = nat_in_journal(sum, i); > > - down_write(&nm_i->nat_tree_lock); > ne = __lookup_nat_cache(nm_i, nid); > if (!ne) { > ne = grab_nat_entry(nm_i, nid); > node_info_from_raw_nat(&ne->ni, &raw_ne); > } > __set_nat_cache_dirty(nm_i, ne); > - up_write(&nm_i->nat_tree_lock); > } > update_nats_in_cursum(sum, -i); > mutex_unlock(&curseg->curseg_mutex); > @@ -1902,7 +1901,6 @@ static void __flush_nat_entry_set(struct f2fs_sb_info *sbi, > struct f2fs_nat_block *nat_blk; > struct nat_entry *ne, *cur; > struct page *page = NULL; > - struct f2fs_nm_info *nm_i = NM_I(sbi); > > /* > * there are two steps to flush nat entries: > @@ -1939,12 +1937,8 @@ static void __flush_nat_entry_set(struct f2fs_sb_info *sbi, > raw_ne = &nat_blk->entries[nid - start_nid]; > } > raw_nat_from_node_info(raw_ne, &ne->ni); > - > - down_write(&NM_I(sbi)->nat_tree_lock); > nat_reset_flag(ne); > __clear_nat_cache_dirty(NM_I(sbi), ne); > - up_write(&NM_I(sbi)->nat_tree_lock); > - > if (nat_get_blkaddr(ne) == NULL_ADDR) > add_free_nid(sbi, nid, false); > } > @@ -1956,9 +1950,7 @@ static void __flush_nat_entry_set(struct f2fs_sb_info *sbi, > > f2fs_bug_on(sbi, set->entry_cnt); > > - down_write(&nm_i->nat_tree_lock); > radix_tree_delete(&NM_I(sbi)->nat_set_root, set->set); > - up_write(&nm_i->nat_tree_lock); > kmem_cache_free(nat_entry_set_slab, set); > } > > @@ -1978,6 +1970,9 @@ void flush_nat_entries(struct f2fs_sb_info *sbi) > > if (!nm_i->dirty_nat_cnt) > return; > + > + down_write(&nm_i->nat_tree_lock); > + > /* > * if there are no enough space in journal to store dirty nat > * entries, remove all entries from journal and merge them > @@ -1986,7 +1981,6 @@ void flush_nat_entries(struct f2fs_sb_info *sbi) > if (!__has_cursum_space(sum, nm_i->dirty_nat_cnt, NAT_JOURNAL)) > remove_nats_in_journal(sbi); > > - down_write(&nm_i->nat_tree_lock); > while ((found = __gang_lookup_nat_set(nm_i, > set_idx, SETVEC_SIZE, setvec))) { > unsigned idx; > @@ -1995,12 +1989,13 @@ void flush_nat_entries(struct f2fs_sb_info *sbi) > __adjust_nat_entry_set(setvec[idx], &sets, > MAX_NAT_JENTRIES(sum)); > } > - up_write(&nm_i->nat_tree_lock); > > /* flush dirty nats in nat entry set */ > list_for_each_entry_safe(set, tmp, &sets, set_list) > __flush_nat_entry_set(sbi, set); > > + up_write(&nm_i->nat_tree_lock); > + > f2fs_bug_on(sbi, nm_i->dirty_nat_cnt); > } > > -- > 2.6.3 > > > ------------------------------------------------------------------------------ > _______________________________________________ > Linux-f2fs-devel mailing list > Linux-f2fs-devel@xxxxxxxxxxxxxxxxxxxxx > https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
