ext4: initialize err_blk before calling __ext4_get_inode_loc

stable inclusion
from stable-v5.10.94
commit 720508dd118d04035875823f44bcd27388ff39b2
bugzilla: https://gitee.com/openeuler/kernel/issues/I531X9

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=720508dd118d04035875823f44bcd27388ff39b2

--------------------------------

commit c27c29c6 upstream.

It is not guaranteed that __ext4_get_inode_loc will definitely set
err_blk pointer when it returns EIO. To avoid using uninitialized
variables, let's first set err_blk to 0.
Reported-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NHarshad Shirwadkar <harshadshirwadkar@gmail.com>
Link: https://lore.kernel.org/r/20211201163421.2631661-1-harshads@google.comSigned-off-by: NTheodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>
Acked-by: NXie XiuQi <xiexiuqi@huawei.com>

fs/ext4/inode.c

@@ -4532,7 +4532,7 @@ static int __ext4_get_inode_loc(struct super_block *sb, unsigned long ino,
 static int __ext4_get_inode_loc_noinmem(struct inode *inode,
 					struct ext4_iloc *iloc)
 {
-	ext4_fsblk_t err_blk;
+	ext4_fsblk_t err_blk = 0;
 	int ret;
 
 	ret = __ext4_get_inode_loc(inode->i_sb, inode->i_ino, NULL, iloc,
@@ -4547,7 +4547,7 @@ static int __ext4_get_inode_loc_noinmem(struct inode *inode,
 
 int ext4_get_inode_loc(struct inode *inode, struct ext4_iloc *iloc)
 {
-	ext4_fsblk_t err_blk;
+	ext4_fsblk_t err_blk = 0;
 	int ret;
 
 	ret = __ext4_get_inode_loc(inode->i_sb, inode->i_ino, inode, iloc,