MDS crash: multiple leases for same bmap in odtable during replay assert

[slovichon]

During startup, replaying of odtable entries when there are multiple leases present can result in a crash:

#0  0x00007ffff5d435d7 in __GI_raise (sig=sig@entry=6)
    at ../nptl/sysdeps/unix/sysv/linux/raise.c:56
#1  0x00007ffff5d44cc8 in __GI_abort () at abort.c:90
#2  0x00000000005d4306 in pfl_abort () at /local/src/p/pfl/init.c:105
#3  0x00000000005e7434 in _psclogv (pci=0xdab480, level=0, options=0,
    fmt=0x6b1de5 "[assert] %s", ap=0x7fffffffdc68)
    at /local/src/p/pfl/log.c:402
#4  0x00000000005e75ca in _psc_fatal (pci=0xdab480, level=0, options=0,
    fmt=0x6b1de5 "[assert] %s") at /local/src/p/pfl/log.c:435
#5  0x00000000004c4b36 in mds_bmap_bml_add (bml=0x3762d80, rw=SL_WRITE,
    prefios=4294967295) at /local/src/p/slash2/slashd/mds.c:977
#6  0x00000000004d114d in mds_bia_odtable_startup_cb (data=0x37ca680,
    odtr=0x7fffffffe250, arg=0x0) at /local/src/p/slash2/slashd/mds.c:1440
#7  0x00000000005f6a0b in pfl_odt_check (t=0x376e720,
    cbf=0x4d021f <mds_bia_odtable_startup_cb>, arg=0x0)
    at /local/src/p/pfl/odtable.c:475
#8  0x00000000004b3511 in main (argc=0, argv=0x7fffffffe4c0)
    at /local/src/p/slash2/slashd/main_mds.c:693