[fuse-devel] creat and file creation

[Guido V. <gu...@vi...>]

Hello, 

in my filesystem, I have to perform a particular action when a file is 
created. Before version 2.5 it was straightforward: a file is only created 
within an `mknod' call, `open' never creates a file.
In version 2.5 I find the `create' system call, which reads "If the file 
does not exist, first create it with the specified mode, and then open it.". 

I have a few doubts:
1. what does happen if the file exists? Is it truncated like in `creat'?
2. Does this call ever get used when the file exists? I made a small program 
where I only call a `creat', and I saw that:
 - `create' is used when the file does not exists;
 - `truncate' and `open' (why not `open' and `ftruncate'?) are used when the 
file is already existing. 

May I assume that `create' always creates a file, and is never called on an 
already existing file? Should this be true, I could perform my "new file" 
action without having to `stat' the file before to check if the file is 
existing... 

Thank you very much,
Guido