Added syscall to update filestats (size) from pager.

After flushing written/truncated pages, stats are updated
so that vfs is synced with new file info such as its size.

tasks/fs0/include/syscalls.h

@@ -18,4 +18,7 @@ int pager_sys_read(l4id_t sender, unsigned long vnum, unsigned long f_offset,
 
 int pager_sys_write(l4id_t sender, unsigned long vnum, unsigned long f_offset,
 		   unsigned long npages, void *pagebuf);
+
+int pager_update_stats(l4id_t sender, unsigned long vnum,
+		       unsigned long newsize);
 #endif /* __FS0_SYSCALLS_H__ */

tasks/fs0/main.c

@@ -92,6 +92,11 @@ void handle_fs_requests(void)
 		pager_sys_write(sender, (unsigned long)mr[0], (unsigned long)mr[1],
 			        (unsigned long)mr[2], (void *)mr[3]);
 		break;
+	case L4_IPC_TAG_PAGER_UPDATE_STATS:
+		pager_update_stats(sender, (unsigned long)mr[0],
+				   (unsigned long)mr[1]);
+		break;
+
 	default:
 		printf("%s: Unrecognised ipc tag (%d) "
 		       "received from tid: %d. Ignoring.\n", __TASKNAME__,

tasks/fs0/src/syscalls.c

@@ -259,6 +259,31 @@ out:
 	return 0;
 }
 
+int pager_update_stats(l4id_t sender, unsigned long vnum,
+		       unsigned long newsize)
+{
+	struct vnode *v;
+	int retval = 0;
+
+	if (sender != PAGER_TID) {
+		retval = -EINVAL;
+		goto out;
+	}
+
+	/* Lookup vnode */
+	if (!(v = vfs_lookup_byvnum(vfs_root.pivot->sb, vnum))) {
+		retval = -EINVAL; /* No such vnode */
+		goto out;
+	}
+
+	v->size = newsize;
+	v->sb->ops->write_vnode(v->sb, v);
+
+out:
+	l4_ipc_return(retval);
+	return 0;
+}
+
 /*
  * This can be solely called by the pager and is not the posix write call.
  * That call is in the pager. This writes the dirty pages of a file
@@ -271,7 +296,6 @@ int pager_sys_write(l4id_t sender, unsigned long vnum, unsigned long f_offset,
 {
 	struct vnode *v;
 	int err, retval = 0;
-	int bytes = 0;
 
 	if (sender != PAGER_TID) {
 		retval = -EINVAL;
@@ -290,17 +314,16 @@ int pager_sys_write(l4id_t sender, unsigned long vnum, unsigned long f_offset,
 		goto out;
 	}
 
-	/* If the file is extended, write automatically extends it */
+	/*
+	 * If the file is extended, write silently extends it.
+	 * But we expect an explicit pager_update_stats from the
+	 * pager to update the new file size on the vnode.
+	 */
 	if ((err = v->fops.write(v, f_offset, npages, pagebuf)) < 0) {
 		retval = err;
 		goto out;
 	}
 
-	/* FIXME: Find a way to properly update new bytes */
-	BUG();
-	v->size += bytes;
-	v->sb->ops->write_vnode(v->sb, v);
-
 out:
 	l4_ipc_return(retval);
 	return 0;

tasks/libl4/include/l4lib/ipcdefs.h

@@ -49,5 +49,6 @@
 #define L4_IPC_TAG_PAGER_OPEN		26	/* vfs sends the pager open file data. */
 #define L4_IPC_TAG_PAGER_READ		27	/* Pager reads file contents from vfs */
 #define L4_IPC_TAG_PAGER_WRITE		28	/* Pager writes file contents to vfs */
+#define L4_IPC_TAG_PAGER_UPDATE_STATS	29	/* Pager updates file stats in vfs */
 
 #endif /* __IPCDEFS_H__ */

tasks/mm0/src/file.c

@@ -237,6 +237,34 @@ int vfs_write(unsigned long vnum, unsigned long file_offset,
 	return err;
 }
 
+/* Writes updated file stats back to vfs. (e.g. new file size) */
+int vfs_update_file_stats(struct vm_file *f)
+{
+	int err;
+
+	l4_save_ipcregs();
+
+	write_mr(L4SYS_ARG0, vm_file_to_vnum(f));
+	write_mr(L4SYS_ARG1, f->length);
+
+	if ((err = l4_sendrecv(VFS_TID, VFS_TID,
+			       L4_IPC_TAG_PAGER_UPDATE_STATS)) < 0) {
+		printf("%s: L4 IPC Error: %d.\n", __FUNCTION__, err);
+		return err;
+	}
+
+	/* Check if syscall was successful */
+	if ((err = l4_get_retval()) < 0) {
+		printf("%s: Pager to VFS write error: %d.\n", __FUNCTION__, err);
+		return err;
+	}
+
+	l4_restore_ipcregs();
+
+	return err;
+
+}
+
 /* Writes pages in cache back to their file */
 int write_file_pages(struct vm_file *f, unsigned long pfn_start,
 		     unsigned long pfn_end)
@@ -261,6 +289,8 @@ int flush_file_pages(struct vm_file *f)
 {
 	write_file_pages(f, 0, __pfn(page_align_up(f->length)));
 
+	vfs_update_file_stats(f);
+
 	return 0;
 }
 

tools/tagsgen/tagsgen_all

@@ -11,6 +11,7 @@ find ./ -name '*.lds' >> tagfilelist
 
 # Use file list to include in tags.
 ctags --languages=C,C++,Asm --recurse -Ltagfilelist
+exuberant-ctags --languages=C,C++,Asm --recurse -Ltagfilelist
 
 cscope -q -k -R -i tagfilelist
 # Remove file list.