[PATCH] Fix for minix crash

Mounting a (corrupt) minix filesystem with zero s_zmap_blocks
gives a spectacular crash on my 2.6.17.8 system, no doubt
because minix/inode.c does an unconditional
	minix_set_bit(0,sbi->s_zmap[0]->b_data);

[akpm@osdl.org: make labels conistent while we're there]

Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 10 insertions, 3 deletions

diff --git a/fs/minix/inode.c b/fs/minix/inode.c
index 9ea91c5eeb7b..330ff9fc7cf0 100644
--- a/fs/minix/inode.c
+++ b/fs/minix/inode.c
@@ -204,6 +204,8 @@ static int minix_fill_super(struct super_block *s, void *data, int silent)
         /*
          * Allocate the buffer map to keep the superblock small.
          */
+        if (sbi->s_imap_blocks == 0 || sbi->s_zmap_blocks == 0)
+                goto out_illegal_sb;
         i = (sbi->s_imap_blocks + sbi->s_zmap_blocks) * sizeof(bh);
         map = kmalloc(i, GFP_KERNEL);
         if (!map)
@@ -263,7 +265,7 @@ out_no_root:
 
 out_no_bitmap:
         printk("MINIX-fs: bad superblock or unable to read bitmaps\n");
-    out_freemap:
+out_freemap:
         for (i = 0; i < sbi->s_imap_blocks; i++)
                 brelse(sbi->s_imap[i]);
         for (i = 0; i < sbi->s_zmap_blocks; i++)
@@ -276,11 +278,16 @@ out_no_map:
                 printk("MINIX-fs: can't allocate map\n");
         goto out_release;
 
+out_illegal_sb:
+        if (!silent)
+                printk("MINIX-fs: bad superblock\n");
+        goto out_release;
+
 out_no_fs:
         if (!silent)
                 printk("VFS: Can't find a Minix or Minix V2 filesystem "
                         "on device %s\n", s->s_id);
-    out_release:
+out_release:
         brelse(bh);
         goto out;
 
@@ -290,7 +297,7 @@ out_bad_hblock:
 
 out_bad_sb:
         printk("MINIX-fs: unable to read superblock\n");
- out:
+out:
         s->s_fs_info = NULL;
         kfree(sbi);
         return -EINVAL;