This patchset adds new ioctl similar to TRIM, that provides several other ways how to clear the unused space. The changelogs are incomplete, for preview not for inclusion yet.
It compiles and has been tested lightly, the clearing modes depend on hw capabilities (secure discard, sector unmapping instead of zeros), so I've tested only zeroing and discard. I personally think the zeroing has a usecase and the other modes were easy to add. Further extensions can be considered, eg. WRITE_SAME, overwriting with a randomly generated pattern, or some filesystem canary patterns that can be used to report unused block read as metadata. As this is modelled after the generic FITRIM ioctl, so this could be a new generic ioctl too. However, last time somebody wanted such ioctl, there was a pushback. I'll consider making a generic version and send it for comments to fsdevel eventually. git://github.com/kdave/btrfs-devel dev/zero-free David Sterba (6): btrfs: extend trim callchain to pass the operation type btrfs: add wrapper to switch clearing operation btrfs: add zeroing clear operation btrfs: add new ioctl BTRFS_IOC_CLEAR_FREE btrfs: add discard secure to clear unused space btrfs: add more zeroout modes for clearing unused space fs/btrfs/ctree.h | 5 +- fs/btrfs/extent-tree.c | 130 ++++++++++++++++++++++++++++++++++++++------ fs/btrfs/free-space-cache.c | 22 +++++--- fs/btrfs/free-space-cache.h | 3 +- fs/btrfs/ioctl.c | 42 ++++++++++++++ include/uapi/linux/btrfs.h | 26 +++++++++ 6 files changed, 199 insertions(+), 29 deletions(-) -- 2.16.2 -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
