3 files changed, 42 insertions, 10 deletions

diff --git a/fs/minix/bitmap.c b/fs/minix/bitmap.c
index 3f32bcb0d9bd..7c82c29429d7 100644
--- a/fs/minix/bitmap.c
+++ b/fs/minix/bitmap.c
@@ -20,10 +20,11 @@ static const int nibblemap[] = { 4,3,3,2,3,2,2,1,3,2,2,1,2,1,1,0 };
 
 static DEFINE_SPINLOCK(bitmap_lock);
 
-static unsigned long count_free(struct buffer_head *map[], unsigned numblocks, __u32 numbits)
+static unsigned long count_free(struct buffer_head *map[], unsigned blocksize, __u32 numbits)
 {
         unsigned i, j, sum = 0;
         struct buffer_head *bh;
+        unsigned numblocks = minix_blocks_needed(numbits, blocksize);
   
         for (i=0; i<numblocks-1; i++) {
                 if (!(bh=map[i])) 
@@ -105,10 +106,12 @@ int minix_new_block(struct inode * inode)
         return 0;
 }
 
-unsigned long minix_count_free_blocks(struct minix_sb_info *sbi)
+unsigned long minix_count_free_blocks(struct super_block *sb)
 {
-        return (count_free(sbi->s_zmap, sbi->s_zmap_blocks,
-                sbi->s_nzones - sbi->s_firstdatazone + 1)
+        struct minix_sb_info *sbi = minix_sb(sb);
+        u32 bits = sbi->s_nzones - (sbi->s_firstdatazone + 1);
+
+        return (count_free(sbi->s_zmap, sb->s_blocksize, bits)
                 << sbi->s_log_zone_size);
 }
 
@@ -273,7 +276,10 @@ struct inode *minix_new_inode(const struct inode *dir, int mode, int *error)
         return inode;
 }
 
-unsigned long minix_count_free_inodes(struct minix_sb_info *sbi)
+unsigned long minix_count_free_inodes(struct super_block *sb)
 {
-        return count_free(sbi->s_imap, sbi->s_imap_blocks, sbi->s_ninodes + 1);
+        struct minix_sb_info *sbi = minix_sb(sb);
+        u32 bits = sbi->s_ninodes + 1;
+
+        return count_free(sbi->s_imap, sb->s_blocksize, bits);
 }
diff --git a/fs/minix/inode.c b/fs/minix/inode.c
index 64cdcd662ffc..1d9e33966db0 100644
--- a/fs/minix/inode.c
+++ b/fs/minix/inode.c
@@ -279,6 +279,27 @@ static int minix_fill_super(struct super_block *s, void *data, int silent)
         else if (sbi->s_mount_state & MINIX_ERROR_FS)
                 printk("MINIX-fs: mounting file system with errors, "
                         "running fsck is recommended\n");
+
+        /* Apparently minix can create filesystems that allocate more blocks for
+         * the bitmaps than needed.  We simply ignore that, but verify it didn't
+         * create one with not enough blocks and bail out if so.
+         */
+        block = minix_blocks_needed(sbi->s_ninodes, s->s_blocksize);
+        if (sbi->s_imap_blocks < block) {
+                printk("MINIX-fs: file system does not have enough "
+                                "imap blocks allocated.  Refusing to mount\n");
+                goto out_iput;
+        }
+
+        block = minix_blocks_needed(
+                        (sbi->s_nzones - (sbi->s_firstdatazone + 1)),
+                        s->s_blocksize);
+        if (sbi->s_zmap_blocks < block) {
+                printk("MINIX-fs: file system does not have enough "
+                                "zmap blocks allocated.  Refusing to mount.\n");
+                goto out_iput;
+        }
+
         return 0;
 
 out_iput:
@@ -339,10 +360,10 @@ static int minix_statfs(struct dentry *dentry, struct kstatfs *buf)
         buf->f_type = sb->s_magic;
         buf->f_bsize = sb->s_blocksize;
         buf->f_blocks = (sbi->s_nzones - sbi->s_firstdatazone) << sbi->s_log_zone_size;
-        buf->f_bfree = minix_count_free_blocks(sbi);
+        buf->f_bfree = minix_count_free_blocks(sb);
         buf->f_bavail = buf->f_bfree;
         buf->f_files = sbi->s_ninodes;
-        buf->f_ffree = minix_count_free_inodes(sbi);
+        buf->f_ffree = minix_count_free_inodes(sb);
         buf->f_namelen = sbi->s_namelen;
         buf->f_fsid.val[0] = (u32)id;
         buf->f_fsid.val[1] = (u32)(id >> 32);
diff --git a/fs/minix/minix.h b/fs/minix/minix.h
index 341e2122879a..6415fe0d2385 100644
--- a/fs/minix/minix.h
+++ b/fs/minix/minix.h
@@ -48,10 +48,10 @@ extern struct minix_inode * minix_V1_raw_inode(struct super_block *, ino_t, stru
 extern struct minix2_inode * minix_V2_raw_inode(struct super_block *, ino_t, struct buffer_head **);
 extern struct inode * minix_new_inode(const struct inode *, int, int *);
 extern void minix_free_inode(struct inode * inode);
-extern unsigned long minix_count_free_inodes(struct minix_sb_info *sbi);
+extern unsigned long minix_count_free_inodes(struct super_block *sb);
 extern int minix_new_block(struct inode * inode);
 extern void minix_free_block(struct inode *inode, unsigned long block);
-extern unsigned long minix_count_free_blocks(struct minix_sb_info *sbi);
+extern unsigned long minix_count_free_blocks(struct super_block *sb);
 extern int minix_getattr(struct vfsmount *, struct dentry *, struct kstat *);
 extern int minix_prepare_chunk(struct page *page, loff_t pos, unsigned len);
 
@@ -88,6 +88,11 @@ static inline struct minix_inode_info *minix_i(struct inode *inode)
         return list_entry(inode, struct minix_inode_info, vfs_inode);
 }
 
+static inline unsigned minix_blocks_needed(unsigned bits, unsigned blocksize)
+{
+        return DIV_ROUND_UP(bits, blocksize * 8);
+}
+
 #if defined(CONFIG_MINIX_FS_NATIVE_ENDIAN) && \
         defined(CONFIG_MINIX_FS_BIG_ENDIAN_16BIT_INDEXED)