Commits
Jaegeuk Kim committed dd802406e39
f2fs: avoid double lock for cp_rwsem
The __f2fs_add_link is covered by cp_rwsem all the time.
This calls init_inode_metadata, which conducts some acl operations including
memory allocation with GFP_KERNEL previously.
But, under memory pressure, f2fs_write_data_page can be called, which also
grabs cp_rwsem too.
In this case, this incurs a deadlock pointed by Chao.
Thread #1 Thread #2
down_read
down_write
down_read
-> here down_read should wait forever.
Reviewed-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>