On Sun, Jan 03, 2016 at 04:15:25AM -0800, Christoph Hellwig wrote: > On Sat, Dec 19, 2015 at 12:56:55AM -0800, Darrick J. Wong wrote: > > Because struct xfs_agfl is 36 bytes long and has a 64-bit integer > > inside it, gcc will quietly round the structure size up to the nearest > > 64 bits -- in this case, 40 bytes. This results in the XFS_AGFL_SIZE > > macro returning incorrect results for v5 filesystems on 64-bit > > machines (118 items instead of 119). As a result, a 32-bit xfs_repair > > will see garbage in AGFL item 119 and complain. > > > > Therefore, tell gcc not to pad the structure so that the AGFL size > > calculation is correct. > > Do you have a testcase for this? Not much aside from: 0. Build kernel/xfsprogs with RFCv4 patches on a 64bit machine. 1. Build kernel/xfsprogs with RFCv4 patches on a 32bit machine. 2. Format a XFS with reflink and rmap on a 64-bit machine, so that the AGFL size is maximized. 3. Mount FS and create a reflinked file. 4. Unmount and xfs_repair with the 32-bit build. I guess we could create a program that compares all the known sizeof(struct xfs_disk_object) values against known good values and stuff that into the xfsprogs build process. --D > > _______________________________________________ > xfs mailing list > xfs@xxxxxxxxxxx > http://oss.sgi.com/mailman/listinfo/xfs _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
