Cosmetic cleanup: fsinit reads sb and calls loginit. initialize icache

in main.c and don't make it disk specific; the icache is shared.  This
doesn't matter since we have only one disk, but conceptually cleaner
and maybe helpful to students for mount lab.

kernel/defs.h

@@ -35,12 +35,12 @@ int             filestat(struct file*, uint64 addr);
 int             filewrite(struct file*, uint64, int n);
 
 // fs.c
-void            readsb(int dev, struct superblock *sb);
+void            fsinit(int);
 int             dirlink(struct inode*, char*, uint);
 struct inode*   dirlookup(struct inode*, char*, uint*);
 struct inode*   ialloc(uint, short);
 struct inode*   idup(struct inode*);
-void            iinit(int dev);
+void            iinit();
 void            ilock(struct inode*);
 void            iput(struct inode*);
 void            iunlock(struct inode*);
@@ -64,7 +64,7 @@ void            kfree(void *);
 void            kinit();
 
 // log.c
-void            initlog(int dev);
+void            initlog(int, struct superblock*);
 void            log_write(struct buf*);
 void            begin_op();
 void            end_op();

kernel/fs.c

@@ -28,7 +28,7 @@ static void itrunc(struct inode*);
 struct superblock sb; 
 
 // Read the super block.
-void
+static void
 readsb(int dev, struct superblock *sb)
 {
   struct buf *bp;
@@ -38,6 +38,15 @@ readsb(int dev, struct superblock *sb)
   brelse(bp);
 }
 
+// Init fs
+void
+fsinit(int dev) {
+  readsb(dev, &sb);
+  if(sb.magic != FSMAGIC)
+    panic("invalid file system");
+  initlog(dev, &sb);
+}
+
 // Zero a block.
 static void
 bzero(int dev, int bno)
@@ -170,7 +179,7 @@ struct {
 } icache;
 
 void
-iinit(int dev)
+iinit()
 {
   int i = 0;
   
@@ -178,10 +187,6 @@ iinit(int dev)
   for(i = 0; i < NINODE; i++) {
     initsleeplock(&icache.inode[i].lock, "inode");
   }
-
-  readsb(dev, &sb);
-  if(sb.magic != FSMAGIC)
-    panic("invalid file system");
 }
 
 static struct inode* iget(uint dev, uint inum);

kernel/log.c

@@ -52,16 +52,14 @@ static void recover_from_log(void);
 static void commit();
 
 void
-initlog(int dev)
+initlog(int dev, struct superblock *sb)
 {
   if (sizeof(struct logheader) >= BSIZE)
     panic("initlog: too big logheader");
 
-  struct superblock sb;
   initlock(&log.lock, "log");
-  readsb(dev, &sb);
+  log.start = sb->logstart;
-  log.start = sb.logstart;
+  log.size = sb->nlog;
-  log.size = sb.nlog;
   log.dev = dev;
   recover_from_log();
 }

kernel/main.c

@@ -23,6 +23,7 @@ main()
     plicinit();      // set up interrupt controller
     plicinithart();  // ask PLIC for device interrupts
     binit();         // buffer cache
+    iinit();         // inode cache
     fileinit();      // file table
     virtio_disk_init(); // emulated hard disk
     userinit();      // first user process

kernel/proc.c

@@ -493,12 +493,11 @@ forkret(void)
   release(&myproc()->lock);
 
   if (first) {
-    // Some initialization functions must be run in the context
+    // File system initialization must be run in the context of a
-    // of a regular process (e.g., they call sleep), and thus cannot
+    // regular process (e.g., because it calls sleep), and thus cannot
     // be run from main().
     first = 0;
-    iinit(ROOTDEV);
+    fsinit(ROOTDEV);
-    initlog(ROOTDEV);
   }
 
   usertrapret();