[PATCH] f2fs: protect free nid operation with cp_rwsem

From: Chao Yu
Date: Fri Mar 17 2017 - 06:47:19 EST


- f2fs_balance_fs_bg
- build_free_nids
- __build_free_nids
- scan_nat_page
- add_free_nid
- f2fs_create
- f2fs_new_inode
- alloc_nid
- remove_free_nid

This patch uses cp_rwsem to protect free nid allocation/initialization
to avoid reusing allocated nid in above scenario.

Signed-off-by: Chao Yu <yuchao0@xxxxxxxxxx>
---
fs/f2fs/inode.c | 2 ++
fs/f2fs/segment.c | 5 ++++-
2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/fs/f2fs/inode.c b/fs/f2fs/inode.c
index 2520fa72b23f..f941410f994a 100644
--- a/fs/f2fs/inode.c
+++ b/fs/f2fs/inode.c
@@ -423,7 +423,9 @@ void f2fs_evict_inode(struct inode *inode)
add_ino_entry(sbi, inode->i_ino, UPDATE_INO);
}
if (is_inode_flag_set(inode, FI_FREE_NID)) {
+ f2fs_lock_op(sbi);
alloc_nid_failed(sbi, inode->i_ino);
+ f2fs_unlock_op(sbi);
clear_inode_flag(inode, FI_FREE_NID);
}
f2fs_bug_on(sbi, err &&
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index 0bf024f62330..f85e1f443c99 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -426,8 +426,11 @@ void f2fs_balance_fs_bg(struct f2fs_sb_info *sbi)

if (!available_free_memory(sbi, FREE_NIDS))
try_to_free_nids(sbi, MAX_FREE_NIDS);
- else
+ else {
+ f2fs_lock_op(sbi);
build_free_nids(sbi, false, false);
+ f2fs_unlock_op(sbi);
+ }

if (!is_idle(sbi))
return;
--
2.8.2.295.g3f1c1d0