fix: do not acquire filesys_lock for tell and seek

src/userprog/syscall.c

@@ -348,12 +348,7 @@ syscall_seek (int fd, unsigned position)
   /* Find the file from the FD. If it does not exist, do nothing. */
   struct open_file *file_info = fd_get_file (fd);
   if (file_info != NULL)
-  {
-    /* File exists: Acquire the file system lock to prevent race conditions. */
-    lock_acquire (&filesys_lock);
     file_seek (file_info->file, position);
-    lock_release (&filesys_lock);
-  }
 }
 
 /* Handles the syscall for returning the next byte in a file referenced by
@@ -367,10 +362,7 @@ syscall_tell (int fd)
   if (file_info == NULL)
     return 0;
 
-  /* Acquire the file system lock to prevent race conditions. */
-  lock_acquire (&filesys_lock);
   unsigned pos = file_tell (file_info->file);
-  lock_release (&filesys_lock);
 
   /* Return the current position in the file. */
   return pos;