omfs: handle set_blocksize failures

omfs uses buffer_heads, which don't handle block size > PAGE_SIZE well.
Without this, mounting we will hit the

        BUG_ON(offset >= folio_size(folio));

in folio_set_bh on the first __bread_gfp call.

Signed-off-by: Christoph Hellwig <hch@lst.de>

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://patch.msgid.link/20260511071701.2456211-11-hch@lst.de
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>

fs/omfs/inode.c

@@ -478,7 +478,8 @@ static int omfs_fill_super(struct super_block *sb, struct fs_context *fc)
 	sb->s_time_min = 0;
 	sb->s_time_max = U64_MAX / MSEC_PER_SEC;
 
-	sb_set_blocksize(sb, 0x200);
+	if (!sb_set_blocksize(sb, 0x200))
+		goto end;
 
 	bh = sb_bread(sb, 0);
 	if (!bh)
@@ -530,7 +531,8 @@ static int omfs_fill_super(struct super_block *sb, struct fs_context *fc)
 	 * Use sys_blocksize as the fs block since it is smaller than a
 	 * page while the fs blocksize can be larger.
 	 */
-	sb_set_blocksize(sb, sbi->s_sys_blocksize);
+	if (!sb_set_blocksize(sb, sbi->s_sys_blocksize))
+		goto out_brelse_bh;
 
 	/*
 	 * ...and the difference goes into a shift.  sys_blocksize is always