We can get NULL pointer to struct super_block.
This commit adds check for such situation.
Fixes: 82cae269cfa9 ("fs/ntfs3: Add initialization of super block")
Thread: https://lore.kernel.org/lkml/20211125140816.GC3109@xsang-OptiPlex-9020/
Signed-off-by: Konstantin Komarov <almaz.alexandrovich@xxxxxxxxxxxxxxxxxxxx>
---
fs/ntfs3/fsntfs.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/fs/ntfs3/fsntfs.c b/fs/ntfs3/fsntfs.c
index 4de9acb16968..38de8cb53183 100644
--- a/fs/ntfs3/fsntfs.c
+++ b/fs/ntfs3/fsntfs.c
@@ -831,14 +831,17 @@ int ntfs_update_mftmirr(struct ntfs_sb_info *sbi, int wait)
{
int err;
struct super_block *sb = sbi->sb;
- u32 blocksize = sb->s_blocksize;
+ u32 blocksize, bytes;
sector_t block1, block2;
- u32 bytes;
- if (!(sbi->flags & NTFS_FLAGS_MFTMIRR))
+ /*
+ * sb can be NULL here. In this case sbi->flags should be 0 too.
+ */
+ if (!sb || !(sbi->flags & NTFS_FLAGS_MFTMIRR))
return 0;
err = 0;
+ blocksize = sb->s_blocksize;
bytes = sbi->mft.recs_mirr << sbi->record_bits;
block1 = sbi->mft.lbo >> sb->s_blocksize_bits;
block2 = sbi->mft.lbo2 >> sb->s_blocksize_bits;
--
2.33.1
