nilfs2: replace BUG_ON and BUG calls triggerable from ioctl

Pekka Enberg advised me:
> It would be nice if BUG(), BUG_ON(), and panic() calls would be
> converted to proper error handling using WARN_ON() calls. The BUG()
> call in nilfs_cpfile_delete_checkpoints(), for example, looks to be
> triggerable from user-space via the ioctl() system call.

This will follow the comment and keep them to a minimum.

Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 5 insertions, 3 deletions

diff --git a/fs/nilfs2/super.c b/fs/nilfs2/super.c
index 2f0e9f7bf152..d0639a6aae9e 100644
--- a/fs/nilfs2/super.c
+++ b/fs/nilfs2/super.c
@@ -841,8 +841,11 @@ nilfs_fill_super(struct super_block *sb, void *data, int silent,
 
         if (sb->s_flags & MS_RDONLY) {
                 if (nilfs_test_opt(sbi, SNAPSHOT)) {
-                        if (!nilfs_cpfile_is_snapshot(nilfs->ns_cpfile,
-                                                      sbi->s_snapshot_cno)) {
+                        err = nilfs_cpfile_is_snapshot(nilfs->ns_cpfile,
+                                                       sbi->s_snapshot_cno);
+                        if (err < 0)
+                                goto failed_sbi;
+                        if (!err) {
                                 printk(KERN_ERR
                                        "NILFS: The specified checkpoint is "
                                        "not a snapshot "
@@ -1163,7 +1166,6 @@ nilfs_get_sb(struct file_system_type *fs_type, int flags,
         } else {
                 struct nilfs_sb_info *sbi = NILFS_SB(s);
 
-                BUG_ON(!sbi || !sbi->s_nilfs);
                 /*
                  * s_umount protects super_block from unmount process;
                  * It covers pointers of nilfs_sb_info and the_nilfs.