f2fs: shrink node_write lock coverage
- to avoid race between checkpoint and quota file writeback, it
just needs to hold read lock of node_write in writeback path.
- node_write lock has covered all LFS data write paths, it's not
necessary, we only need to hold node_write lock at write path of
quota file.
This refactors commit ca7f76e68074 ("f2fs: fix wrong discard space").
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index c78ce08..cbdf062 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -2719,8 +2719,20 @@ int f2fs_write_single_data_page(struct page *page, int *submitted,
/* Dentry/quota blocks are controlled by checkpoint */
if (S_ISDIR(inode->i_mode) || IS_NOQUOTA(inode)) {
+ /*
+ * We need to wait for node_write to avoid block allocation during
+ * checkpoint. This can only happen to quota writes which can cause
+ * the below discard race condition.
+ */
+ if (IS_NOQUOTA(inode))
+ down_read(&sbi->node_write);
+
fio.need_lock = LOCK_DONE;
err = f2fs_do_write_data_page(&fio);
+
+ if (IS_NOQUOTA(inode))
+ up_read(&sbi->node_write);
+
goto done;
}
