1 files changed, 73 insertions, 0 deletions

diff --git a/src/fs/block_dev.c b/src/fs/block_dev.c
new file mode 100644
index 0000000..a50ae3f
--- /dev/null
+++ b/src/fs/block_dev.c
@@ -0,0 +1,73 @@
+/*
+ *  linux/fs/block_dev.c
+ *
+ *  (C) 1991  Linus Torvalds
+ */
+
+#include <errno.h>
+
+#include <linux/sched.h>
+#include <linux/kernel.h>
+#include <asm/segment.h>
+#include <asm/system.h>
+
+int block_write(int dev, long * pos, char * buf, int count)
+{
+        int block = *pos >> BLOCK_SIZE_BITS;
+        int offset = *pos & (BLOCK_SIZE-1);
+        int chars;
+        int written = 0;
+        struct buffer_head * bh;
+        register char * p;
+
+        while (count>0) {
+                chars = BLOCK_SIZE - offset;
+                if (chars > count)
+                        chars=count;
+                if (chars == BLOCK_SIZE)
+                        bh = getblk(dev,block);
+                else
+                        bh = breada(dev,block,block+1,block+2,-1);
+                block++;
+                if (!bh)
+                        return written?written:-EIO;
+                p = offset + bh->b_data;
+                offset = 0;
+                *pos += chars;
+                written += chars;
+                count -= chars;
+                while (chars-->0)
+                        *(p++) = get_fs_byte(buf++);
+                bh->b_dirt = 1;
+                brelse(bh);
+        }
+        return written;
+}
+
+int block_read(int dev, unsigned long * pos, char * buf, int count)
+{
+        int block = *pos >> BLOCK_SIZE_BITS;
+        int offset = *pos & (BLOCK_SIZE-1);
+        int chars;
+        int read = 0;
+        struct buffer_head * bh;
+        register char * p;
+
+        while (count>0) {
+                chars = BLOCK_SIZE-offset;
+                if (chars > count)
+                        chars = count;
+                if (!(bh = breada(dev,block,block+1,block+2,-1)))
+                        return read?read:-EIO;
+                block++;
+                p = offset + bh->b_data;
+                offset = 0;
+                *pos += chars;
+                read += chars;
+                count -= chars;
+                while (chars-->0)
+                        put_fs_byte(*(p++),buf++);
+                brelse(bh);
+        }
+        return read;
+}