Hi all, This is the eighth revision of a patchset that adds to XFS kernel support for mapping multiple file logical blocks to the same physical block (reflink/deduplication), implements the beginnings of online metadata scrubbing and preening, and implements reverse mapping for the realtime device. There shouldn't be any incompatible on-disk format changes, pending a thorough review of the patches within. Online scrub support consists of three pieces -- first, an ioctl that maps physical extents to their owners; second, various in-kernel metadata scrubbing ioctls to examine metadata records and cross-reference them with other filesystem metadata; and third, a userspace component to initiate kernel scrubbing, walk all inodes and the directory tree, and scrub data extents. The first few patches in this series implements the GETFSMAP ioctl that maps a device number and physical extent either to filesystem metadata or to a range of file blocks. The initial implementation uses the reverse-mapping B+tree to supply the mapping information, however a fallback implementation based on the free space btrees is also provided. The flexibility of having both implementations is important when it comes to the userspace tool -- even without the owner/offset data, we still have enough information to set up a read verification. The bulk of the patches implement in-kernel scrubbing. This is implemented as a new ioctl. Pass in a metadata type and a control number (when applicable); the kernel will examine each record in that metadata structure looking for obvious logical errors. External corruption should be discoverable via the checksum embedded in each (v5) filesystem metadata block. When applicable, the metadata record will be cross-referenced with the other metadata structures to look for discrepancies. Should any errors be found, an error code is returned to userspace, which should take the filesystem offline and repair it. The final patch in the series enables xfs_scrub to query the per-AG block reservations so that the summary counters can be sanity-checked. If you're going to start using this mess, you probably ought to just pull from my github trees for kernel[1], xfsprogs[2], xfstests[3], xfs-docs[4], and man-pages[5]. The kernel patches in the git trees should apply to 4.8-rc3; xfsprogs patches to for-next; and xfstest to master. The patches have been xfstested with x64, ppc64, and armhf; all tests in the clone and rmap groups pass. AFAICT they don't cause any new failures for the 'auto' group. This is an extraordinary way to eat your data. Enjoy! Comments and questions are, as always, welcome. --D [1] https://github.com/djwong/linux/tree/djwong-devel [2] https://github.com/djwong/xfsprogs/tree/djwong-devel [3] https://github.com/djwong/xfstests/tree/djwong-devel [4] https://github.com/djwong/xfs-documentation/tree/djwong-devel [5] https://github.com/djwong/man-pages/tree/djwong-devel _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
