ext4: combine ext4_handle_error() and save_error_info()

mainline inclusion
from mainline-v5.11-rc4
commit e789ca0c
category: bugfix
bugzilla: 50839
CVE: NA

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save_error_info() is always called together with ext4_handle_error().
Combine them into a single call and move unconditional bits out of
save_error_info() into ext4_handle_error().

Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20201216101844.22917-2-jack@suse.cz


Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Ye Bin <yebin10@huawei.com>
Reviewed-by: zhangyi (F) <yi.zhang@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>