4 files changed, 92 insertions, 10 deletions
diff --git a/kernel/fs/block.c b/kernel/fs/block.c
index b3f7386..caf97d2 100644
--- a/kernel/fs/block.c
+++ b/kernel/fs/block.c
@@ -1,10 +1,9 @@
-#include <kernel/hd.h>
 #include <sys/types.h>
 
-size_t block_read(void *buf, size_t block, size_t len) {
-  return hd_read_block(buf, block, len);
+int block_read(void *buf, size_t block) {
+  return -1;
 }
 
-size_t block_write(void *buf, size_t block, size_t len) {
-  return hd_write_block(buf, block, len);
+int block_write(void *buf, size_t block) {
+  return -1;
 }
diff --git a/kernel/fs/buffer.c b/kernel/fs/buffer.c
new file mode 100644
index 0000000..7405738
--- /dev/null
+++ b/kernel/fs/buffer.c
@@ -0,0 +1,82 @@
+#include <kernel/con.h>
+#include <kernel/fs.h>
+#include <stdint.h>
+#include <string.h>
+
+/* memory dedicated to the block cache */
+#define BSTART 0x80000
+#define BEND 0xA0000
+
+static struct buffer *lru;
+static struct buffer *mru;
+
+struct buffer *buffer_get_block(uint16_t device, uint16_t block);
+
+void buffer_init(void) {
+  int c = 0;
+  struct buffer *last = NULL;
+  struct buffer *b = (struct buffer*) BSTART;
+  void *d = (void*) (BEND - BLOCK_SIZE);
+
+  while(d > (void*) b) {
+    memset(b, 0, sizeof(struct buffer));
+
+    b->b_data = d;
+    b->b_prev = last;
+
+    if(last)
+      last->b_next = b;
+
+    last = b;
+
+    b = (struct buffer*) ((void*) b + sizeof(struct buffer));
+    d = (void*) (d - (void*) BLOCK_SIZE);
+
+    c++;
+  }
+
+  lru = (struct buffer*) BSTART;
+  mru = last;
+
+  printk("[buf] Buffers initialized (0x%x buffers in pool)\n", c);
+}
+
+struct buffer *buffer_get_block(uint16_t device, uint16_t block) {
+  int ret;
+  struct buffer **p = &mru;
+  struct buffer *b;
+
+  /* check if the requested block is already in the cache */
+  while(*p) {
+    if((*p)->b_device == device && (*p)->b_block == block) {
+      /* put the buffer back at the MRU end of the list */
+      (*p)->b_next = NULL;
+      (*p)->b_prev = mru;
+      mru = *p;
+      return *p;
+    }
+    p = &(*p)->b_prev;
+  }
+
+  /* find a buffer at the end of the LRU list */
+  b = lru;
+  lru = lru->b_next;
+  lru->b_prev = NULL;
+  ret = block_read(b->b_data, block);
+  /* abort if we failed to read in the block */
+  if(ret < 0) {
+    /* release the allocated buffer to the pool */
+    lru->b_prev = b;
+    b->b_next = lru;
+    b->b_prev = NULL;
+    lru = b;
+    return NULL;
+  }
+  b->b_device = device;
+  b->b_block = block;
+  /* put the buffer back at the MRU end of the list */
+  b->b_next = NULL;
+  b->b_prev = mru;
+  mru = b;
+  return b;
+}
diff --git a/kernel/fs/fs.c b/kernel/fs/fs.c
index 792668e..e0d9205 100644
--- a/kernel/fs/fs.c
+++ b/kernel/fs/fs.c
@@ -1,6 +1,5 @@
 #include <kernel/con.h>
 #include <kernel/fs.h>
-#include <kernel/hd.h>
 #include <kernel/kernel.h>
 #include <kernel/sched.h>
 #include <kernel/tty.h>
@@ -22,7 +21,9 @@ void fs_init(void) {
   memset(&sblocks, 0, sizeof(sblocks));
   memset(&ftable, 0, sizeof(ftable));
 
-  hd_init();
+  buffer_init();
+
+  /* hd_init(); */
 
   mount_root();
 }
diff --git a/kernel/fs/mount.c b/kernel/fs/mount.c
index 47911fb..9cdf49b 100644
--- a/kernel/fs/mount.c
+++ b/kernel/fs/mount.c
@@ -6,12 +6,12 @@
 struct super_block sblocks[NRSUPER];
 
 void mount_root(void) {
-  size_t ret;
+  int ret;
   char buf[BLOCK_SIZE];
   struct super_block *s = (void*) buf;
 
-  ret = block_read(buf, 1, 1);
-  if(ret < 1) {
+  ret = block_read(buf, 1);
+  if(ret < 0) {
     printk("[fs] Failed to read super block\n");
     return;
   }