Protect busy VfsObjs during opening and deleting

kernel/hal/hal.h

@@ -19,6 +19,7 @@ size_t hal_strspn(const char *s, const char *accept);
 char *hal_strcpy(char *dest, const char *src);
 char *hal_strchr(const char *s, int c);
 char *hal_strstr(const char *str, const char *substring);
+char *hal_string_combine(char *dest, const char *src);
 void hal_wait(uint32_t ms);
 int32_t hal_randnum(void);
 

kernel/hal/util.c

@@ -140,3 +140,13 @@ char *hal_strstr(const char *str, const char *substring)
 
     return NULL;
 }
+
+char *hal_string_combine(char *dest, const char *src) {
+  size_t i, j;
+  for(i = 0; dest[i] != '\0'; i++);
+  for(j = 0; src[j] != '\0'; j++) {
+    dest[i+j] = src[j];
+  }
+  dest[i+j] = '\0';
+  return dest;
+}

kernel/vfs/vfs.c

@@ -14,6 +14,28 @@
 #include "dlmalloc/malloc.h"
 
 VfsTable VFS_TABLE;
+VfsBusyObjs VFS_BUSY_VOBJS;
+
+#define CHECK_BUSY_VFSOBJ() \
+  char *tmpbuf = dlmalloc(VFS_MOUNTPOINT_LABEL_MAX+1+VFS_PATH_MAX); \
+  \
+  hal_memset(tmpbuf, 0, VFS_MOUNTPOINT_LABEL_MAX+1+VFS_PATH_MAX); \
+  hal_string_combine(tmpbuf, mountpoint); \
+  hal_string_combine(tmpbuf, ":"); \
+  hal_string_combine(tmpbuf, path); \
+  \
+  bool busy = false; \
+  VfsObj *vobj, *vobjtmp; \
+  spinlock_acquire(&VFS_BUSY_VOBJS.spinlock); \
+  LL_FOREACH_SAFE(VFS_BUSY_VOBJS.vobjs, vobj, vobjtmp) { \
+    if (hal_strcmp(vobj->path, tmpbuf) == 0) { \
+      busy = true; \
+      break; \
+    } \
+  } \
+  spinlock_release(&VFS_BUSY_VOBJS.spinlock); \
+  \
+  dlfree(tmpbuf);
 
 void vfs_init_littlefs(VfsMountPoint *mp, bool format) {
   struct lfs_config *cfg = dlmalloc(sizeof(*cfg));
@@ -95,6 +117,12 @@ int32_t vfs_fetchdirent(char *mountpoint, const char *path, FsDirent *direntbuf,
 }
 
 int32_t vfs_delete(char *mountpoint, const char *path) {
+  CHECK_BUSY_VFSOBJ()
+
+  if (busy) {
+    return E_NOTYET;
+  }
+
   VfsMountPoint *mp = NULL;
 
   spinlock_acquire(&VFS_TABLE.spinlock);
@@ -156,6 +184,12 @@ int32_t vfs_unmount(char *mountpoint) {
 }
 
 VfsObj *vfs_open(char *mountpoint, const char *path, uint32_t flags) {
+  CHECK_BUSY_VFSOBJ()
+
+  if (busy) {
+    return NULL;
+  }
+
   VfsMountPoint *mp = NULL;
 
   spinlock_acquire(&VFS_TABLE.spinlock);
@@ -166,16 +200,34 @@ VfsObj *vfs_open(char *mountpoint, const char *path, uint32_t flags) {
     return NULL;
   }
 
-  return mp->open(mp, path, flags);
+  VfsObj *vobj1 = mp->open(mp, path, flags);
+  if (vobj1 == NULL) {
+    return NULL;
+  }
+
+  hal_string_combine(vobj1->path, mountpoint);
+  hal_string_combine(vobj1->path, ":");
+  hal_string_combine(vobj1->path, path);
+
+  spinlock_acquire(&VFS_BUSY_VOBJS.spinlock);
+  LL_APPEND(VFS_BUSY_VOBJS.vobjs, vobj1);
+  spinlock_release(&VFS_BUSY_VOBJS.spinlock);
+
+  return vobj1;
 }
 
 void vfs_close(VfsObj *vobj) {
+  spinlock_acquire(&VFS_BUSY_VOBJS.spinlock);
+  LL_REMOVE(VFS_BUSY_VOBJS.vobjs, vobj);
+  spinlock_release(&VFS_BUSY_VOBJS.spinlock);
   vobj->cleanup(vobj);
 }
 
 void vfs_init(void) {
   hal_memset(&VFS_TABLE, 0, sizeof(VFS_TABLE));
   spinlock_init(&VFS_TABLE.spinlock);
+  hal_memset(&VFS_BUSY_VOBJS, 0, sizeof(VFS_BUSY_VOBJS));
+  spinlock_init(&VFS_BUSY_VOBJS.spinlock);
 
   {
     RamSdInitExtra extra = { .capacity = baseimg_getsize(), .preallocbuffer = (uint8_t *)baseimg_getaddr() };

kernel/vfs/vfs.h

@@ -30,7 +30,9 @@ enum {
 #define VFS_PATH_MAX 1024
 
 typedef struct VfsObj {
+  struct VfsObj *next;
   SpinLock spinlock;
+  char path[VFS_MOUNTPOINT_LABEL_MAX+1+VFS_PATH_MAX];
   void *extra;
   size_t extrasize;
   struct VfsMountPoint *vmp;
@@ -40,6 +42,13 @@ typedef struct VfsObj {
   void (*cleanup)(struct VfsObj *vobj);
 } VfsObj;
 
+typedef struct {
+  SpinLock spinlock;
+  VfsObj *vobjs;
+} VfsBusyObjs;
+
+extern VfsBusyObjs VFS_BUSY_VOBJS;
+
 typedef struct VfsMountPoint {
   int _hshtbstate;
   char label[VFS_MOUNTPOINT_LABEL_MAX];