On 2018年08月08日 00:39, David Sterba wrote: > On Sun, Aug 05, 2018 at 06:39:57PM +0800, Lu Fengqi wrote: >> This patchset will add the BTRFS_IOC_SUBVOL_UNDELETE ioctl for online >> btrfs subvolume undelete. >> >> And btrfs subvolume undelete subcommand was added to btrfs-progs. >> >> So user can use the following command to recover all the subolume that >> is left on the device. The recovered subvolume will be link to <dest> dir >> named to <name_prefix><subvol_id>. > > Hm, I don't agree with the proposed interface - to recover all deleted > subvolumes. IMO this should recover just one subvolume of a given id a > to given directory. > > The ioctl structure has to be reworked, I've skimmed the code and saw > some suspicious things but will have a look after the interface is > settled.
My concern is, is such purpose really needed? Yes, it's possible user made some mistake and want to get back the data. But putting an ioctl for 'undelete', then user may consider btrfs is so powerful that can undelete everything. In short, this undelete feature gives user too high expectation. And don't expect user really to read man pages. There are already tons of reports where user execute btrfs check --repair without realizing --repair is pretty dangerous (and thanks to the work done to repair, it normally doesn't cause catastrophic result, but sometimes it indeed causes extra damage) And when user tried and failed due to deleted tree blocks, they will get even more frustrated or even betrayed. I prefer to put such undelete as an off-line rescue tool, instead of making it online with an ioctl interface. Thanks, Qu > -- > 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 >
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