Thanks Mike, this is good stuff. :) + Justin On 06/09/2014, at 8:19 PM, mike wrote: > I upgraded the client to Gluster 3.5.2, but there is no difference. > > The bug is almost certainly in the Fuse client. If I remount the filesystem with NFS, the problem is no longer observable. > > I spent a little time looking through the xlator/fuse-bridge to see where the offsets are coming from, but I'm really not familiar enough with the code, so it is slow going. > > Unfortunately, I'm still having trouble reproducing this in a python script that could be readily attached to a bug report. > > I'll take a crack at that again, but I will a file a bug anyway for completeness. > > On Sep 5, 2014, at 7:10 PM, mike <mike@xxxxxxxxxxxxxxxxxxxx> wrote: > >> I have narrowed down the source of the bug. >> >> Here is an strace of glusterfsd http://fpaste.org/131455/40996378/ >> >> The first line represents a write that does *not* make it into the underlying file. >> >> The last line is the write that stomps the earlier write. >> >> As I said, the client file is opened in O_APPEND mode, but on the glusterfsd side, the file is just O_CREAT|O_WRONLY. The means the offsets to pwrite() need to be valid. >> >> I correlated this to a tcpdump I took and I can see that in fact, the RPCs being sent have the wrong offset. Interestingly, glusterfs.write-is-append = 0, which I wouldn't have expected. >> >> I think the bug lies in the glusterfs fuse client. >> >> As to your question about Gluster 3.5.2, I may be able to do that if I am unable to find the bug in the source. >> >> -Mike >> >> On Sep 5, 2014, at 6:16 PM, Justin Clift <justin@xxxxxxxxxxx> wrote: >> >>> On 06/09/2014, at 12:10 AM, mike wrote: >>>> I have found that the O_APPEND flag is key to this failure - I had overlooked that flag when reading the strace and trying to cobble up a minimal reproduction. >>>> >>>> I now have a small pair of python scripts that can reliably reproduce this failure. >>> >>> >>> As a thought, is there a reasonable way you can test this on GlusterFS 3.5.2? >>> >>> There were some important bug fixes in 3.5.2 (from 3.5.1). >>> >>> Note I'm not saying yours is one of them, I'm just asking if it's >>> easy to test and find out. :) >>> >>> Regards and best wishes, >>> >>> Justin Clift >>> >>> -- >>> GlusterFS - http://www.gluster.org >>> >>> An open source, distributed file system scaling to several >>> petabytes, and handling thousands of clients. >>> >>> My personal twitter: twitter.com/realjustinclift >>> >> > -- GlusterFS - http://www.gluster.org An open source, distributed file system scaling to several petabytes, and handling thousands of clients. My personal twitter: twitter.com/realjustinclift _______________________________________________ Gluster-users mailing list Gluster-users@xxxxxxxxxxx http://supercolony.gluster.org/mailman/listinfo/gluster-users
