-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 2014-06-25 22:41, Shyamsundar Ranganathan wrote: > Hi Anders, > > There are multiple problems that I see in the test provided, here is > answering one of them and the reason why this occurs. It does get > into the code and functions a bit, but bottom line is that on a code > path the setattr that DHT does, misses setting the SGID bit causing > the problem observed. > > - When directory is healed on a newly added brick it loses the SGID > mode bit > > This is happening due to 2 reasons, > > mkdir does not honor the SGID mode bit [1]. So when initially > creating the directory when there is a single brick, an strace of the > mkdir command shows an fchmod which actually changes the mode of the > file to add the SGID bit to it. > > In DHT we get into dht_lookup_dir_cbk, as a part of the lookup when > creating the new directory .../dir2, as the graph has changed due to > a brick addition (otherwise we would have gone into revalidate path > where the previous fix was made). Here we call the function, > dht_selfheal_directory which would create the missing directories, > with the expected attributes. > > DHT winds a call to mkdir as a part of the dht_selfheal_directory (in > dht_selfheal_dir_mkdir where it winds a call to mkdir for all > subvolumes that have the directory missing) with the right mode bits > (in this case with the SGID bit). As the POSIX layer on the brick > calls mkdir, the SGID bit is not set for the newly created directory > due to [1]. I think this depends on the sgid bit of the parent directory on the brick, which might indicate that mkdir_p should be checked as well. > Further to calling mkdir DHT now winds an setattr to set the mode > bits straight, but ends up using the mode bits that are returned in > the iatt (stat) information by the just concluded mkdir wind, which > has the SGID bit missing, as mkdir returns the stat information from > posix_mkdir, by doing a stat post mkdir. Hence we never end up > setting the SGID bit in the setattr part of DHT. To me this does not quite explain how a directory (sometimes) winds up with permissions set to 0. > > Rectification of the problem would be in (need to close out some more > analysis) dht_selfheal_dir_mkdir_cbk, where we need to pass to the > subsequent dht_selfheal_dir_setattr the right mode bits to set on the > directories. > > I will provide a patch for the above issue, post testing out the same > with the provided script, possibly tomorrow. I would be very much obliged for this. > This would make the > directory equal on all the bricks, and further discrepancies from the > mount point or on the backed should not be seen. Make sure to use the last version (currently 3) of the test script from https://bugzilla.redhat.com/show_bug.cgi?id=1110262 > One of the other problems seems to stem from which stat information > we pick in DHT to return for the mount, the above fix would take care > of that issue as well, but still something that needs some > understanding and possible correction. > > [1] see NOTES in, man 2 mkdir > > Shyam > Thanks /Anders - -- Anders Blomdell Email: anders.blomdell@xxxxxxxxxxxxxx Department of Automatic Control Lund University Phone: +46 46 222 4625 P.O. Box 118 Fax: +46 46 138118 SE-221 00 Lund, Sweden -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iQEcBAEBAgAGBQJTq842AAoJENZYyvaDG8NcxYwH/j0JVcchfdR6RllE7nrB0LSR SmjjYxWqr/dg+897jQ0SnIl8SHsI4HCqywtctnk9q3n2sDNG+N6GJQeWXdCycfAs QZW9wcyDmyqt4FD4kivFtuX4yzHTO1T6Y5G/CMSl6JWhY6gQd9GuPH3t3l31u/43 PuSS4Sey2coaQnKidMVMlCPvLwkzNQtPOgaN7081PUvQu6Ab0IAuuBg2diHwwvPH RbYmBwVbCgAtd1MP7cfbiCnKy3EKUMSXYzgzoCptyTNy/PTIlysOl8bgWTSpN6AW sb0j/dz4BRRK/i6IXtpxX1Tf/j9tmYSAG7e3OvavXCqt2m6imh4/ZUIM6h95KN4= =S77i -----END PGP SIGNATURE----- _______________________________________________ Gluster-devel mailing list Gluster-devel@xxxxxxxxxxx http://supercolony.gluster.org/mailman/listinfo/gluster-devel
