udf: Do not bother looking for prealloc extents if i_lenExtents matches i_size

stable inclusion
from stable-v5.10.161
commit db873b770d8a1ea1ec41aa6cdc9573c4623a0293
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I7P7OH

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=db873b770d8a1ea1ec41aa6cdc9573c4623a0293



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

commit 6ad53f0f upstream.

If rounded block-rounded i_lenExtents matches block rounded i_size,
there are no preallocation extents. Do not bother walking extent linked
list.

CC: stable@vger.kernel.org
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: sanglipeng <sanglipeng1@jd.com>