atomic file operations

[Sergei Sharonov]

Hello,

I am working on a logging application where a (large) log file is appended 
with 1 kByte data chunks. I cannot miss a chunk or duplicate a chunk in 
case of a power failure. Kermit will be used to ensure atomicity for 
incomming data chunks. Now, the question is what file operations on JFFS2 
are guaranteed to be atomic/transactional? 
Is a write of 1024 bytes atomic? 
Does it relate to the page size in any way? BTW I am using NAND and the page 
may vary between 512 and 2048 bytes depending on a device.
Is file rename atomic?
Other file operations?

Second issue is: How badly these small chunks will affect my mount time?

Thanks in advance

Sergei Sharonov