fs: do not update freeing inode i_io_list

After commit cbfecb927f42 ("fs: record I_DIRTY_TIME even if inode
already has I_DIRTY_INODE") writeback_single_inode can push inode with
I_DIRTY_TIME set to b_dirty_time list. In case of freeing inode with
I_DIRTY_TIME set this can happen after deletion of inode from i_io_list
at evict. Stack trace is following.

evict
fat_evict_inode
fat_truncate_blocks
fat_flush_inodes
writeback_inode
sync_inode_metadata(inode, sync=0)
writeback_single_inode(inode, wbc) <- wbc->sync_mode == WB_SYNC_NONE

This will lead to use after free in flusher thread.

Similar issue can be triggered if writeback_single_inode in the
stack trace update inode->i_io_list. Add explicit check to avoid it.

Fixes: cbfecb927f42 ("fs: record I_DIRTY_TIME even if inode already has I_DIRTY_INODE")
Reported-by: syzbot+6ba92bd00d5093f7e371@syzkaller.appspotmail.com
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Svyatoslav Feldsherov <feldsherov@google.com>
Link: https://lore.kernel.org/r/20221115202001.324188-1-feldsherov@google.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
