2009/11/16 TARUISI Hiroaki <taruishi.hir...@jp.fujitsu.com>: > I made Snapshot/subvolume listing feature. > > This feature consists of two patches, for kernel(ioctl), > and for progs(btrfsctl). I send these two patches as response > of this mail soon. > > New option '-l' is introduced to btrfsctl for listing. > > If this option is specified, btrfsctl call new ioctl. New ioctl > searches root tree and enumerates subtrees. For each subtrees, > ioctl searches directory path to tree root, and enumerates > more descendant until no more subtree is found. > > MANPAGE-like option description and examples are as follows. > > OPTIONS > -l _file_ > List all snapshot/subvolume directories under a tree > which _file_ belongs to. > > EXAMPLES > # btrfsctl -l /work/btrfs > Base path = /work/btrfs/ > No. Tree ID Subvolume Relative Path > 1 256 ss1/ > 2 257 ss2/ > 3 258 svs1/ss1/ > 4 259 svs1/ss2/ > 5 260 svs2/ss1/ > 6 261 svs2/ss2/ > 7 262 ss3/ > 8 263 ss4/ > 9 264 sv_pool/ > 10 265 sv_pool/ss01/ > 11 266 sv_pool/ss02/ > 12 267 sv_pool/ss03/ > 13 268 sv_pool/ss04/ > 14 269 sv_pool/ss05/ > 15 270 sv_pool/ss06/ > 16 271 sv_pool/ss07/ > 17 272 sv_pool/ss08/ > 18 273 sv_pool/ss09/ > 19 274 sv_pool/ss10/ > operation complete > Btrfs v0.19-9-gd67dad2 >
Thank you for doing this. I have a quick look at the patches. It seems the ioctl returns full path to each subvolume and uses sequence ID to indicate the progress of listing. Every time the ioctl is called, it tries building full list of subvolume, then skip entries that already returned. I think the API is suboptimal, a getdents like API is better. (The ioctl only lists subvolumes within a given subvolume, the user program call the ioctl recursively to list all subvolumes.) Yan, Zheng -- 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
