exofs: Fix CRASH on very early IO errors.

If at exofs_fill_super() we had an early termination
do to any error, like an IO error while reading the
super-block. We would crash inside exofs_free_sbi().

This is because sbi->oc.numdevs was set to 1, before
we actually have a device table at all.

Fix it by moving the sbi->oc.numdevs = 1 to after the
allocation of the device table.
Reported-by: NJohannes Schild <JSchild@gmx.de>

Stable: This is a bug since v3.2.0
CC: Stable Tree <stable@kernel.org>
Signed-off-by: NBoaz Harrosh <bharrosh@panasas.com>

fs/exofs/super.c

@@ -745,7 +745,6 @@ static int exofs_fill_super(struct super_block *sb, void *data, int silent)
 	sbi->one_comp.obj.partition = opts->pid;
 	sbi->one_comp.obj.id = 0;
 	exofs_make_credential(sbi->one_comp.cred, &sbi->one_comp.obj);
-	sbi->oc.numdevs = 1;
 	sbi->oc.single_comp = EC_SINGLE_COMP;
 	sbi->oc.comps = &sbi->one_comp;
 
@@ -804,6 +803,7 @@ static int exofs_fill_super(struct super_block *sb, void *data, int silent)
 			goto free_sbi;
 
 		ore_comp_set_dev(&sbi->oc, 0, od);
+		sbi->oc.numdevs = 1;
 	}
 
 	__sbi_read_stats(sbi);