Mount of XFS filesystem hangs in xfs_ail_push_all_sync

Issue

The RHEL 7 server fails to complete its boot sequence due to /var hosted by XFS filesystem failing to mount. The mount command hangs in kernel mode with the following kernel stack trace:

schedule+0x29/0x70
xfs_ail_push_all_sync+0xc1/0x110 [xfs]
xfs_log_quiesce+0x33/0x70 [xfs]
xfs_log_unmount+0x12/0x30 [xfs]
xfs_mountfs+0x5ea/0x730 [xfs]
xfs_fs_fill_super+0x2b2/0x330 [xfs]
mount_bdev+0x1b0/0x1f0
xfs_fs_mount+0x15/0x20 [xfs]
mount_fs+0x39/0x1b0
vfs_kern_mount+0x5f/0xf0
do_mount+0x24e/0xa30
SyS_mount+0x96/0xf0
system_call_fastpath+0x16/0x1b

Any attempt to fix the filesystem by xfs_repair will hang because the hanging mount is blocking access to the filesystem superblock.