ext4: avoid kmemcheck complaint from reading uninitialized memory

commit 7e731bc9a12339f344cddf82166b82633d99dd86 upstream.

Commit 03179fe923 introduced a kmemcheck complaint in
ext4_da_get_block_prep() because we save and restore
ei->i_da_metadata_calc_last_lblock even though it is left
uninitialized in the case where i_da_metadata_calc_len is zero.

This doesn't hurt anything, but silencing the kmemcheck complaint
makes it easier for people to find real bugs.

Addresses https://bugzilla.kernel.org/show_bug.cgi?id=45631
(which is marked as a regression).

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index a071348..129925a 100644 (file)
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -904,6 +904,7 @@ static struct inode *ext4_alloc_inode(struct super_block *sb)
        ei->i_reserved_meta_blocks = 0;
        ei->i_allocated_meta_blocks = 0;
        ei->i_da_metadata_calc_len = 0;
+       ei->i_da_metadata_calc_last_lblock = 0;
        spin_lock_init(&(ei->i_block_reservation_lock));
 #ifdef CONFIG_QUOTA
        ei->i_reserved_quota = 0;