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Date: Sat, 2 Jan 2016 17:26:05 -0800
From: Jaegeuk Kim <jaegeuk@...nel.org>
To: linux-kernel@...r.kernel.org, linux-fsdevel@...r.kernel.org,
linux-f2fs-devel@...ts.sourceforge.net
Cc: Jaegeuk Kim <jaegeuk@...nel.org>
Subject: [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.
Signed-off-by: Jaegeuk Kim <jaegeuk@...nel.org>
---
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
--
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