f2fs: avoid f2fs_lock_op for IPU writes

Currently, if we do get_node_of_data before f2fs_lock_op, there may be dead lock
as follows, where process A would be in infinite loop, and B will NOT be awaked.

Process A(cp):            Process B:
f2fs_lock_all(sbi)
                        get_dnode_of_data <---- lock dn.node_page
flush_nodes             f2fs_lock_op

So, this patch adds f2fs_trylock_op to avoid f2fs_lock_op done by IPU.

Signed-off-by: Hou Pengyang <houpengyang@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

1 files changed, 12 insertions, 1 deletions

diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index c6643783adff..f61e095947c8 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -799,6 +799,12 @@ enum temp_type {
 	NR_TEMP_TYPE,
 };
 
+enum need_lock_type {
+	LOCK_REQ = 0,
+	LOCK_DONE,
+	LOCK_RETRY,
+};
+
 struct f2fs_io_info {
 	struct f2fs_sb_info *sbi;	/* f2fs_sb_info pointer */
 	enum page_type type;	/* contains DATA/NODE/META/META_FLUSH */
@@ -810,7 +816,7 @@ struct f2fs_io_info {
 	struct page *page;	/* page to be written */
 	struct page *encrypted_page;	/* encrypted page */
 	bool submitted;		/* indicate IO submission */
-	bool need_lock;		/* indicate we need to lock cp_rwsem */
+	int need_lock;		/* indicate we need to lock cp_rwsem */
 };
 
 #define is_read_io(rw) ((rw) == READ)
@@ -1279,6 +1285,11 @@ static inline void f2fs_lock_op(struct f2fs_sb_info *sbi)
 	down_read(&sbi->cp_rwsem);
 }
 
+static inline int f2fs_trylock_op(struct f2fs_sb_info *sbi)
+{
+	return down_read_trylock(&sbi->cp_rwsem);
+}
+
 static inline void f2fs_unlock_op(struct f2fs_sb_info *sbi)
 {
 	up_read(&sbi->cp_rwsem);