Am 22.08.2014 um 09:35 schrieb Peter Lieven: > Some code in the block layer makes potentially huge allocations. Failure > is not completely unexpected there, so avoid aborting qemu and handle > out-of-memory situations gracefully. > > This patch addresses the allocations in the iscsi block driver. > > Signed-off-by: Kevin Wolf <kw...@redhat.com> > Acked-by: Paolo Bonzini <pbonz...@redhat.com> > Reviewed-by: Benoit Canet <ben...@irqsave.net> > Reviewed-by: Eric Blake <ebl...@redhat.com> > --- > block/iscsi.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/block/iscsi.c b/block/iscsi.c > index 84aa22a..06afa78 100644 > --- a/block/iscsi.c > +++ b/block/iscsi.c > @@ -893,7 +893,10 @@ coroutine_fn iscsi_co_write_zeroes(BlockDriverState > *bs, int64_t sector_num, > nb_blocks = sector_qemu2lun(nb_sectors, iscsilun); > > if (iscsilun->zeroblock == NULL) { > - iscsilun->zeroblock = g_malloc0(iscsilun->block_size); > + iscsilun->zeroblock = g_try_malloc0(iscsilun->block_size); > + if (iscsilun->zeroblock == NULL) { > + return -ENOMEM; > + } > } > > iscsi_co_init_iscsitask(iscsilun, &iTask);
Unfortunately, I missed that one. The zeroblock is typicalls 512 Byte or 4K depending on the blocksize. What is significantly larger is the allocationmap. It is typically created on iscsi_open, but is also recreated on iscsi_truncate. I don't have the context why this patch was introduced, but I would vote for introducing a bitmap_try_new and issue a warning if the allocation fails. The allocationmap is optional we can work without it. If the pointer is NULL its not used. Peter