Hi All, I have one another solution to heal user xattr but before implement it i would like to discuss with you.
Can i call function (dht_dir_xattr_heal internally it is calling syncop_setxattr) to heal xattr in dht_getxattr_cbk in last after make sure we have a valid xattr. In function(dht_dir_xattr_heal) it will copy blindly all user xattr on all subvolume or i can compare subvol xattr with valid xattr if there is any mismatch then i will call syncop_setxattr otherwise no need to call. syncop_setxattr. Let me know if this approach is suitable. Regards Mohit Agrawal On Wed, Sep 7, 2016 at 10:27 PM, Pranith Kumar Karampuri < pkara...@redhat.com> wrote: > > > On Wed, Sep 7, 2016 at 9:46 PM, Mohit Agrawal <moagr...@redhat.com> wrote: > >> 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. >> > > I think first up subvol is different for different mounts as per my > understanding, I could be wrong. > > >> >> 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 >>> >> >> > > > -- > Pranith >
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