From: Ben Gras <ben@minix3.org>
Date: Wed, 6 Jun 2007 15:14:58 +0000 (+0000)
Subject: firstdatazone is prone to overflowing with many inodes.
X-Git-Tag: v3.1.3a^2~1
X-Git-Url: http://zhaoyanbai.com/repos/Bv9ARM.ch03.html?a=commitdiff_plain;h=2862654b07215ce7ae5c5b19b0f2005378c289c5;p=minix.git

firstdatazone is prone to overflowing with many inodes.
---

diff --git a/commands/simple/mkfs.c b/commands/simple/mkfs.c
index faddeb51d..efcf3abe3 100755
--- a/commands/simple/mkfs.c
+++ b/commands/simple/mkfs.c
@@ -450,6 +450,7 @@ ino_t inodes;
   unsigned int i;
   int inodeblks;
   int initblks;
+  zone_t zi, zz, zd;
 
   zone_t initzones, nrzones, v1sq, v2sq;
   zone_t zo;
@@ -468,14 +469,14 @@ ino_t inodes;
 	sup->s_nzones = 0;	/* not used in V2 - 0 forces errors early */
 	sup->s_zones = zones;
   }
-  sup->s_imap_blocks = bitmapsize((bit_t) (1 + inodes), block_size);
-  sup->s_zmap_blocks = bitmapsize((bit_t) zones, block_size);
+  sup->s_imap_blocks = zi = bitmapsize((bit_t) (1 + inodes), block_size);
+  sup->s_zmap_blocks = zz = bitmapsize((bit_t) zones, block_size);
   inode_offset = sup->s_imap_blocks + sup->s_zmap_blocks + 2;
   inodeblks = (inodes + inodes_per_block - 1) / inodes_per_block;
   initblks = inode_offset + inodeblks;
   initzones = (initblks + (1 << zone_shift) - 1) >> zone_shift;
   nrzones = nrblocks >> zone_shift;
-  sup->s_firstdatazone = (initblks + (1 << zone_shift) - 1) >> zone_shift;
+  sup->s_firstdatazone = zd = (initblks + (1 << zone_shift) - 1) >> zone_shift;
   zoff = sup->s_firstdatazone - 1;
   sup->s_log_zone_size = zone_shift;
   if (fs_version == 1) {
@@ -503,6 +504,16 @@ ino_t inodes;
 	}
   }
 
+  /* checks for size */
+  if(zi != sup->s_imap_blocks || sup->s_zmap_blocks != zz) {
+  	fprintf(stderr, "imap blocks or zmap blocks fields too small?\n");
+	exit(1);
+  }
+  if(sup->s_firstdatazone != zd) {
+  	fprintf(stderr, "firstdatazone field too small?\n");
+	exit(1);
+  }
+
   zone_size = 1 << zone_shift;	/* nr of blocks per zone */
 
   if (lseek(fd, (off_t) _STATIC_BLOCK_SIZE, SEEK_SET) == (off_t) -1) {