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system-callsfsync

Can a call to write(2) be interrupted by OS with an fsync(2)

I have a loop of write(2) with arbitrary amount of data + EOL and an fsync(2) appending to a file line by line.

Can a crash of the process leave me with a file that has half of the data from the write(2) call written to file? My theory is that if the OS calls fsync occasionally, there might be a coincidence of it happening during a call the write(2) leaving the file with half of the line written, without the ending new line.

Solution

  • Yes. Even without a crash, you might have a partial line written as the write call might not write all the data passed to it -- it might return a short write.