xfs: validity check agbnos on the AGFL

mainline inclusion
from mainline-v6.4-rc5
commit 3148ebf2
category: bugfix
bugzilla: 188883, https://gitee.com/openeuler/kernel/issues/I76JSK
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=3148ebf2c0782340946732bfaf3073d23ac833fa



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

If the agfl or the indexing in the AGF has been corrupted, getting a
block form the AGFL could return an invalid block number. If this
happens, bad things happen. Check the agbno we pull off the AGFL
and return -EFSCORRUPTED if we find somethign bad.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Dave Chinner <david@fromorbit.com>

Conflicts:
	fs/xfs/libxfs/xfs_alloc.c

Signed-off-by: Long Li <leo.lilong@huawei.com>