[PATCH] UFS sanity checks

The real rule is not "block size is at most 32Kb", it's "block size is
at most 8 times the fragment size".

fs/ufs/super.c

@@ -651,16 +651,34 @@ static int ufs_fill_super(struct super_block *sb, void *data, int silent)
 	uspi->s_fmask = fs32_to_cpu(sb, usb1->fs_fmask);
 	uspi->s_fshift = fs32_to_cpu(sb, usb1->fs_fshift);
 
-	/* block size must be a power-of-two between 4k and 32k */
-	if ((uspi->s_bsize & (uspi->s_bsize-1)) ||
-	    (uspi->s_bsize < 4096 || uspi->s_bsize > 32768)) {
-		printk("ufs_read_super: fs_bsize %u != {4096, 8192, 16384, 32768}\n", uspi->s_bsize);
+	if (uspi->s_fsize & (uspi->s_fsize - 1)) {
+		printk("ufs_read_super: fragment size %u is not a power of 2\n",
+			uspi->s_fsize);
+			goto failed;
+	}
+	if (uspi->s_fsize < 512) {
+		printk("ufs_read_super: fragment size %u is too small\n"
+			uspi->s_fsize);
+		goto failed;
+	}
+	if (uspi->s_fsize > 4096) {
+		printk("ufs_read_super: fragment size %u is too large\n"
+			uspi->s_fsize);
+		goto failed;
+	}
+	if (uspi->s_bsize & (uspi->s_bsize - 1)) {
+		printk("ufs_read_super: block size %u is not a power of 2\n",
+			uspi->s_bsize);
+		goto failed;
+	}
+	if (uspi->s_bsize < 4096) {
+		printk("ufs_read_super: block size %u is too small\n"
+			uspi->s_fsize);
 		goto failed;
 	}
-	/* fragment size must be a power-of-two between 512 and 4096 bytes */
-	if ((uspi->s_fsize & (uspi->s_fsize-1)) ||
-	    (uspi->s_fsize < 512 || uspi->s_fsize > 4096)) {
-		printk("ufs_read_super: fs_fsize %u != {512, 1024, 2048. 4096}\n", uspi->s_fsize);
+	if (uspi->s_bsize / uspi->s_fsize > 8) {
+		printk("ufs_read_super: too many fragments per block (%u)\n"
+			uspi->s_bsize / uspi->s_fsize);
 		goto failed;
 	}
 	if (uspi->s_fsize != block_size || uspi->s_sbsize != super_block_size) {