[PATCH 1/2] f2fs: unlock cp_rwsem early for IPU writes

[Chao Yu]

For IPU writes, there won't be any udpates in dnode page since we
will reuse old block address instead of allocating new one, so we
don't need to lock cp_rwsem during IPU IO submitting.

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

diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index e984a42eabf4..32d5a3b38a3f 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -1357,6 +1357,8 @@ int do_write_data_page(struct f2fs_io_info *fio)
 			!is_cold_data(page) &&
 			!IS_ATOMIC_WRITTEN_PAGE(page) &&
 			need_inplace_update(inode))) {
+		f2fs_unlock_op(F2FS_I_SB(inode));
+		fio->cp_rwsem_locked = false;
 		err = rewrite_data_page(fio);
 		set_inode_flag(inode, FI_UPDATE_WRITE);
 		trace_f2fs_do_write_data_page(page, IPU);
@@ -1392,6 +1394,7 @@ static int __write_data_page(struct page *page, bool *submitted,
 		.page = page,
 		.encrypted_page = NULL,
 		.submitted = false,
+		.cp_rwsem_locked = true,
 	};
 
 	trace_f2fs_writepage(page, DATA);
@@ -1449,7 +1452,8 @@ static int __write_data_page(struct page *page, bool *submitted,
 		err = do_write_data_page(&fio);
 	if (F2FS_I(inode)->last_disk_size < psize)
 		F2FS_I(inode)->last_disk_size = psize;
-	f2fs_unlock_op(sbi);
+	if (fio.cp_rwsem_locked)
+		f2fs_unlock_op(sbi);
 done:
 	if (err && err != -ENOENT)
 		goto redirty_out;
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index a39749412803..5c3e60551df5 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -795,6 +795,7 @@ struct f2fs_io_info {
 	struct page *page;	/* page to be written */
 	struct page *encrypted_page;	/* encrypted page */
 	bool submitted;		/* indicate IO submission */
+	bool cp_rwsem_locked;	/* indicate cp_rwsem is held */
 };
 
 #define is_read_io(rw) ((rw) == READ)
-- 
2.12.2.510.ge1104a5ee539