nilfs2: add reader's lock for cno in nilfs_ioctl_sync
This adds reader's lock for the_nilfs->cno in nilfs_ioctl_sync,
for the_nilfs->cno should be proctected by segctor_sem when reading.
Signed-off-by: Jiro SEKIBA <jir@unicus.jp>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
diff --git a/fs/nilfs2/ioctl.c b/fs/nilfs2/ioctl.c
index 8e5cad0..313d0a2 100644
--- a/fs/nilfs2/ioctl.c
+++ b/fs/nilfs2/ioctl.c
@@ -601,13 +601,17 @@
{
__u64 cno;
int ret;
+ struct the_nilfs *nilfs;
ret = nilfs_construct_segment(inode->i_sb);
if (ret < 0)
return ret;
if (argp != NULL) {
- cno = NILFS_SB(inode->i_sb)->s_nilfs->ns_cno - 1;
+ nilfs = NILFS_SB(inode->i_sb)->s_nilfs;
+ down_read(&nilfs->ns_segctor_sem);
+ cno = nilfs->ns_cno - 1;
+ up_read(&nilfs->ns_segctor_sem);
if (copy_to_user(argp, &cno, sizeof(cno)))
return -EFAULT;
}