On 09/30/2016 10:08 AM, Pranith Kumar Karampuri wrote:
Does samba/gfapi/nfs-ganesha have options to disable readdirp?
AFAIK, currently there is no option to disable/enable readdirp in gfapi & nfs-ganesha (not sure about samba). But looks like nfs-ganesha seem to be always using readdir, which I plan to change it to readdirp in the near future to check if it improves performance of stat on small-files. Could you please summarize the issues with using readdirp?
Thanks, Soumya
On Fri, Sep 30, 2016 at 10:04 AM, Pranith Kumar Karampuri <pkarampu@xxxxxxxxxx <mailto:pkarampu@xxxxxxxxxx>> wrote: What if the lower xlators want to set the entry->inode to NULL and clear the entry->d_stat to force a lookup on the name? i.e. gfid-split-brain/ia_type mismatches. On Fri, Sep 30, 2016 at 10:00 AM, Raghavendra Gowdappa <rgowdapp@xxxxxxxxxx <mailto:rgowdapp@xxxxxxxxxx>> wrote: ----- Original Message ----- > From: "Raghavendra Gowdappa" <rgowdapp@xxxxxxxxxx <mailto:rgowdapp@xxxxxxxxxx>> > To: "Pranith Kumar Karampuri" <pkarampu@xxxxxxxxxx <mailto:pkarampu@xxxxxxxxxx>> > Cc: "Shyam Ranganathan" <srangana@xxxxxxxxxx <mailto:srangana@xxxxxxxxxx>>, "Nithya Balachandran" <nbalacha@xxxxxxxxxx <mailto:nbalacha@xxxxxxxxxx>>, "Gluster Devel" > <gluster-devel@xxxxxxxxxxx <mailto:gluster-devel@xxxxxxxxxxx>> > Sent: Friday, September 30, 2016 9:58:34 AM > Subject: Re: Dht readdir filtering out names > > > > ----- Original Message ----- > > From: "Pranith Kumar Karampuri" <pkarampu@xxxxxxxxxx <mailto:pkarampu@xxxxxxxxxx>> > > To: "Raghavendra Gowdappa" <rgowdapp@xxxxxxxxxx <mailto:rgowdapp@xxxxxxxxxx>> > > Cc: "Shyam Ranganathan" <srangana@xxxxxxxxxx <mailto:srangana@xxxxxxxxxx>>, "Nithya Balachandran" > > <nbalacha@xxxxxxxxxx <mailto:nbalacha@xxxxxxxxxx>>, "Gluster Devel" > > <gluster-devel@xxxxxxxxxxx <mailto:gluster-devel@xxxxxxxxxxx>> > > Sent: Friday, September 30, 2016 9:53:44 AM > > Subject: Re: Dht readdir filtering out names > > > > On Fri, Sep 30, 2016 at 9:50 AM, Raghavendra Gowdappa <rgowdapp@xxxxxxxxxx <mailto:rgowdapp@xxxxxxxxxx>> > > wrote: > > > > > > > > > > > ----- Original Message ----- > > > > From: "Pranith Kumar Karampuri" <pkarampu@xxxxxxxxxx <mailto:pkarampu@xxxxxxxxxx>> > > > > To: "Raghavendra Gowdappa" <rgowdapp@xxxxxxxxxx <mailto:rgowdapp@xxxxxxxxxx>> > > > > Cc: "Shyam Ranganathan" <srangana@xxxxxxxxxx <mailto:srangana@xxxxxxxxxx>>, "Nithya Balachandran" < > > > nbalacha@xxxxxxxxxx <mailto:nbalacha@xxxxxxxxxx>>, "Gluster Devel" > > > > <gluster-devel@xxxxxxxxxxx <mailto:gluster-devel@xxxxxxxxxxx>> > > > > Sent: Friday, September 30, 2016 9:15:04 AM > > > > Subject: Re: Dht readdir filtering out names > > > > > > > > On Fri, Sep 30, 2016 at 9:13 AM, Raghavendra Gowdappa < > > > rgowdapp@xxxxxxxxxx <mailto:rgowdapp@xxxxxxxxxx>> > > > > wrote: > > > > > > > > > dht_readdirp_cbk has different behaviour for directories and files. > > > > > > > > > > 1. If file, pick the dentry (passed from subvols as part of readdirp > > > > > response) if the it corresponds to data file. > > > > > 2. If directory pick the dentry if readdirp response is from > > > hashed-subvol. > > > > > > > > > > In all other cases, the dentry is skipped and not passed to higher > > > > > layers/application. To elaborate, the dentries which are ignored are: > > > > > 1. dentries corresponding to linkto files. > > > > > 2. dentries from non-hashed subvols corresponding to directories. > > > > > > > > > > Since the behaviour is different for different filesystem objects, > > > > > dht > > > > > needs ia_type to choose its behaviour. > > > > > > > > > > ----- Original Message ----- > > > > > > From: "Pranith Kumar Karampuri" <pkarampu@xxxxxxxxxx <mailto:pkarampu@xxxxxxxxxx>> > > > > > > To: "Shyam Ranganathan" <srangana@xxxxxxxxxx <mailto:srangana@xxxxxxxxxx>>, "Raghavendra > > > Gowdappa" < > > > > > rgowdapp@xxxxxxxxxx <mailto:rgowdapp@xxxxxxxxxx>>, "Nithya Balachandran" > > > > > > <nbalacha@xxxxxxxxxx <mailto:nbalacha@xxxxxxxxxx>> > > > > > > Cc: "Gluster Devel" <gluster-devel@xxxxxxxxxxx <mailto:gluster-devel@xxxxxxxxxxx>> > > > > > > Sent: Friday, September 30, 2016 8:39:28 AM > > > > > > Subject: Dht readdir filtering out names > > > > > > > > > > > > hi, > > > > > > In dht_readdirp_cbk() there is a check about skipping files > > > > > without > > > > > > ia_type. Could you help me understand why this check is added? > > > > > > There > > > are > > > > > > times when users have to delete gfid of the entries and trigger > > > something > > > > > > like 'find . | xargs stat' to heal the gfids. This case would fail > > > if we > > > > > > skip entries without gfid, if the lower xlators don't send stat > > > > > information > > > > > > for them. > > > > > > > > > > Probably we can make readdirp_cbk not rely on ia_type and pass _all_ > > > > > dentries received by subvols to application without filtering. > > > > > However > > > we > > > > > should make this behaviour optional and use this only for recovery > > > setups. > > > > > If we don't rely on ia_type (during non error scenarios), > > > > > applications > > > end > > > > > up seeing duplicate dentries in readdir listing. > > > > > > > > > > > > > That means dht_readdir() gives duplicate entries? As per the code it > > > seems > > > > like it... > > > > > > No. It follows the filtering logic of "pick dentry only from hashed > > > subvol". This logic doesn't need ia_type. Now, that you brought the topic > > > of dht_readdir, I've another solution for your use case (Basically don't > > > use readdirp :) ): > > > > > > 1. mount glusterfs with "--use-readdirp=no" option. > > > 2. disable md-cache/stat-prefetch as it converts all readdir calls into > > > readdirp calls > > > > > > > Probably the ones in dht as well? i.e. use-readdirp option. > > No. dht doesn't convert a readdir into readdirp. The option you are referring > to might be "readdir-optimize" which is something different. Sorry. I was wrong. There is an option in dht too, to force using readdirp. As you said, we should disable that too. > > > > > > > > > > > Use this only for recovery setups :). > > > > > > > > > > > > > > > > > > > > > > > > > > > > -- > > > > > > Pranith > > > > > > > > > > > > > > > > regards, > > > > > Raghavendra > > > > > > > > > > > > > > > > > > > > > -- > > > > Pranith > > > > > > > > > > > > > > > -- > > Pranith > > > -- Pranith -- Pranith
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