Messages in this thread | | | Date | Thu, 5 May 2022 06:48:47 +0900 | From | asmadeus@codewrec ... | Subject | Re: 9p EBADF with cache enabled (Was: 9p fs-cache tests/benchmark (was: 9p fscache Duplicate cookie detected)) |
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Christian Schoenebeck wrote on Wed, May 04, 2022 at 08:33:36PM +0200: > On Dienstag, 3. Mai 2022 12:21:23 CEST asmadeus@codewreck.org wrote: > > - add some complex code to track the exact byte range that got updated > > in some conditions e.g. WRONLY or read fails? > > That'd still be useful depending on how the backend tracks file mode, > > qemu as user with security_model=mapped-file keeps files 600 but with > > passthrough or none qemu wouldn't be able to read the file regardless of > > what we do on client... > > Christian, if you still have an old kernel around did that use to work? > > Sorry, what was the question, i.e. what should I test / look for precisely? :)
I was curious if older kernel does not issue read at all, or issues read on writeback fid correctly opened as root/RDRW
You can try either the append.c I pasted a few mails back or the dd commands, as regular user.
$ dd if=/dev/zero of=test bs=1M count=1 $ chmod 400 test # drop cache or remount $ dd if=/dev/urandom of=test bs=102 seek=2 count=1 conv=notrunc dd: error writing 'test': Bad file descriptor
... But honestly I should just find the time to do it myself, this has been dragging on for too long... -- Dominique
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