Is it safe to call rename(tmppath, path)
without calling fsync(tmppath_fd)
first?
I want the path to always point to a complete file. I care mainly about Ext4. Is the rename() promised to be safe in all future Linux kernel versions?
A usage example in Python:
def store_atomically(path, data):
tmppath = path + ".tmp"
output = open(tmppath, "wb")
output.write(data)
output.flush()
os.fsync(output.fileno()) # The needed fsync().
output.close()
os.rename(tmppath, path)
No.
Look at libeatmydata, and this presentation:
http://www.oscon.com/oscon2008/public/schedule/detail/3172
by Stewart Smith from MySql.
In case it is offline/no longer available, I keep a copy of it: