From 59bbd474abb9dd6a0c1a74df758ec29c7a8b150f Mon Sep 17 00:00:00 2001 From: Jaegeuk Kim Date: Tue, 7 May 2013 20:47:40 +0900 Subject: f2fs: cover free_nid management with spin_lock After build_free_nids() searches free nid candidates from nat pages and current journal blocks, it checks all the candidates if they are allocated so that the nat cache has its nid with an allocated block address. In this procedure, previously we used list_for_each_entry_safe(fnid, next_fnid, &nm_i->free_nid_list, list). But, this is not covered by free_nid_list_lock, resulting in null pointer bug. This patch moves this checking routine inside add_free_nid() in order not to use the spin_lock. Signed-off-by: Jaegeuk Kim --- fs/f2fs/node.c | 34 ++++++++++++++++++---------------- 1 file changed, 18 insertions(+), 16 deletions(-) diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c index e42934e689c5..3df43b4efd89 100644 --- a/fs/f2fs/node.c +++ b/fs/f2fs/node.c @@ -1249,9 +1249,11 @@ static void __del_from_free_nid_list(struct free_nid *i) kmem_cache_free(free_nid_slab, i); } -static int add_free_nid(struct f2fs_nm_info *nm_i, nid_t nid) +static int add_free_nid(struct f2fs_nm_info *nm_i, nid_t nid, bool build) { struct free_nid *i; + struct nat_entry *ne; + bool allocated = false; if (nm_i->fcnt > 2 * MAX_FREE_NIDS) return -1; @@ -1259,6 +1261,18 @@ static int add_free_nid(struct f2fs_nm_info *nm_i, nid_t nid) /* 0 nid should not be used */ if (nid == 0) return 0; + + if (!build) + goto retry; + + /* do not add allocated nids */ + read_lock(&nm_i->nat_tree_lock); + ne = __lookup_nat_cache(nm_i, nid); + if (ne && nat_get_blkaddr(ne) != NULL_ADDR) + allocated = true; + read_unlock(&nm_i->nat_tree_lock); + if (allocated) + return 0; retry: i = kmem_cache_alloc(free_nid_slab, GFP_NOFS); if (!i) { @@ -1309,7 +1323,7 @@ static void scan_nat_page(struct f2fs_nm_info *nm_i, blk_addr = le32_to_cpu(nat_blk->entries[i].block_addr); BUG_ON(blk_addr == NEW_ADDR); if (blk_addr == NULL_ADDR) { - if (add_free_nid(nm_i, start_nid) < 0) + if (add_free_nid(nm_i, start_nid, true) < 0) break; } } @@ -1317,7 +1331,6 @@ static void scan_nat_page(struct f2fs_nm_info *nm_i, static void build_free_nids(struct f2fs_sb_info *sbi) { - struct free_nid *fnid, *next_fnid; struct f2fs_nm_info *nm_i = NM_I(sbi); struct curseg_info *curseg = CURSEG_I(sbi, CURSEG_HOT_DATA); struct f2fs_summary_block *sum = curseg->sum_blk; @@ -1354,22 +1367,11 @@ static void build_free_nids(struct f2fs_sb_info *sbi) block_t addr = le32_to_cpu(nat_in_journal(sum, i).block_addr); nid = le32_to_cpu(nid_in_journal(sum, i)); if (addr == NULL_ADDR) - add_free_nid(nm_i, nid); + add_free_nid(nm_i, nid, true); else remove_free_nid(nm_i, nid); } mutex_unlock(&curseg->curseg_mutex); - - /* remove the free nids from current allocated nids */ - list_for_each_entry_safe(fnid, next_fnid, &nm_i->free_nid_list, list) { - struct nat_entry *ne; - - read_lock(&nm_i->nat_tree_lock); - ne = __lookup_nat_cache(nm_i, fnid->nid); - if (ne && nat_get_blkaddr(ne) != NULL_ADDR) - remove_free_nid(nm_i, fnid->nid); - read_unlock(&nm_i->nat_tree_lock); - } } /* @@ -1659,7 +1661,7 @@ flush_now: } if (nat_get_blkaddr(ne) == NULL_ADDR && - add_free_nid(NM_I(sbi), nid) <= 0) { + add_free_nid(NM_I(sbi), nid, false) <= 0) { write_lock(&nm_i->nat_tree_lock); __del_from_nat_cache(nm_i, ne); write_unlock(&nm_i->nat_tree_lock); -- cgit v1.2.3