NFS server receives multiple inotify events on new file

Question

I have 2 machines in our datacenter:

The public server exposes part of the internal servers's storage through ftp. When files are uploaded to the ftp, the files in fact end up on the internal storage. But when watching the inotify events on the internal server's storage, i notice the file gets written in chunks, probably due to buffering at client side. The software on the internal server, watches the inotify events, to determine if new files have arrived. But due to the NFS manner of writing the files, there is no good way of telling when a file is complete. Is there a way of telling the NFS client to write files in only one operation, or is there a work around for this behaviour?

EDIT:

The events i get on the internal server, when uploading a file of around 900 MB are:

./ CREATE big_buck_bunny_1080p_surround.avi
# after the CREATE i get around 250K MODIFY and CLOSE_WRITE,CLOSE events:
./ MODIFY big_buck_bunny_1080p_surround.avi
./ CLOSE_WRITE,CLOSE big_buck_bunny_1080p_surround.avi
# when the upload finishes i get a CLOSE_NOWRITE,CLOSE
./ CLOSE_NOWRITE,CLOSE big_buck_bunny_1080p_surround.avi

of course, i could listen to the CLOSE_NOWRITE event, but reading inotify documentation says:

close_nowrite
A watched file or a file within a watched directory was closed, after being opened in read-only mode.

Which is not exactly the same as 'the file is complete'. The only workaround I see, is to use .part or .filepart files and move them, once uploaded, to the original filename and ignore the .part files in my storage watcher. Disadvantage is I'll have to explain this to customers, how to upload with .part. Not many ftp clients support this by default.

Answer 1

Basically, if you want to check when the write operations is completed, monitor the event IN_CLOSE_WRITE.

IN_CLOSE_WRITE gets "fired" when a file gets closed which was open for writing. Even if the file gets transferred in chunks, the FTP server will close the file only after the whole file has been transferred.