Hi Pranith,
In current approach i am getting list of xattr from first up volume and update the user attributes from that xattr to all other volumes. I have assumed first up subvol is source and rest of them are sink as we are doing same in dht_dir_attr_heal. Regards Mohit Agrawal On Wed, Sep 7, 2016 at 9:34 PM, Pranith Kumar Karampuri <pkara...@redhat.com > wrote: > hi Mohit, > How does dht find which subvolume has the correct list of xattrs? > i.e. how does it determine which subvolume is source and which is sink? > > On Wed, Sep 7, 2016 at 2:35 PM, Mohit Agrawal <moagr...@redhat.com> wrote: > >> Hi, >> >> I am trying to find out solution of one problem in dht specific to user >> xattr healing. >> I tried to correct it in a same way as we are doing for healing dir >> attribute but i feel it is not best solution. >> >> To find a right way to heal xattr i want to discuss with you if anyone >> does have better solution to correct it. >> >> Problem: >> In a distributed volume environment custom extended attribute value >> for a directory does not display correct value after stop/start the brick. >> If any extended attribute value is set for a directory after stop the brick >> the attribute value is not updated on brick after start the brick. >> >> Current approach: >> 1) function set_user_xattr to store user extended attribute in >> dictionary >> 2) function dht_dir_xattr_heal call syncop_setxattr to update the >> attribute on all volume >> 3) Call the function (dht_dir_xattr_heal) for every directory lookup >> in dht_lookup_revalidate_cbk >> >> Psuedocode for function dht_dir_xatt_heal is like below >> >> 1) First it will fetch atttributes from first up volume and store into >> xattr. >> 2) Run loop on all subvolume and fetch existing attributes from every >> volume >> 3) Replace user attributes from current attributes with xattr user >> attributes >> 4) Set latest extended attributes(current + old user attributes) inot >> subvol. >> >> >> In this current approach problem is >> >> 1) it will call heal function(dht_dir_xattr_heal) for every directory >> lookup without comparing xattr. >> 2) The function internally call syncop xattr for every subvolume that >> would be a expensive operation. >> >> I have one another way like below to correct it but again in this one >> it does have dependency on time (not sure time is synch on all bricks or >> not) >> >> 1) At the time of set extended attribute(setxattr) change time in >> metadata at server side >> 2) Compare change time before call healing function in >> dht_revalidate_cbk >> >> Please share your input on this. >> Appreciate your input. >> >> Regards >> Mohit Agrawal >> >> _______________________________________________ >> Gluster-devel mailing list >> Gluster-devel@gluster.org >> http://www.gluster.org/mailman/listinfo/gluster-devel >> > > > > -- > Pranith >
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