Date: Mon, 22 Jun 2015 23:42:02 +0530 From: Prasad Joshi <prasadjoshi.linux@gmail.com> To: soc-status@freebsd.org Cc: Xin LI <d@delphij.net> Subject: Re: [gsoc15] dynamically discover bes Message-ID: <CALJbWert-6-0fa6_%2BdK0N8zcU053GyRSQ8hRoQ5DGfBxeGGu4g@mail.gmail.com> In-Reply-To: <CALJbWerHWL8=P-hJ57V8SfZTyJ5uV9g-=a2x%2B3epGLuit0vn3w@mail.gmail.com> References: <CALJbWeobZj9BqDoYW5Si9NWFFxd2q=w1EsBPVOxcNML-vZF3aQ@mail.gmail.com> <CALJbWerHWL8=P-hJ57V8SfZTyJ5uV9g-=a2x%2B3epGLuit0vn3w@mail.gmail.com>
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Week 4 update - I have been able to discover BEs on console. I could detect active BE. Created list of BEs. Code to sort BEs on object number, name, or timestamp is added. - I am able to boot from nonactive BE to some extent. At the moment, code requires me to enter BE number to boot from. Tasks next week 1. Identify a problem with be bootup. 2. Pass mount point info through env variable to loader. 3. Start with console based menu. Thanks and Regards, Prasad On Jun 15, 2015 7:48 PM, "Prasad Joshi" <prasadjoshi.linux@gmail.com> wrote: > Week 3 status > ========== > After understanding on disk representation of snapshots and clones, I > have been able to find names of the BEs created using beadm command. I > could print the BE names on console. > > The next task would be to convert BE names to object numbers, create > list of BEs. > > Thanks and Regards, > Prasad > > On Tue, Jun 9, 2015 at 6:36 AM, Prasad Joshi > <prasadjoshi.linux@gmail.com> wrote: > > Last week I mostly worked on understanding beadm and gptzfsboot code > > > > beadm create prepares new BE by creating a snapshot and clone of that > > snapshot. beadm activate command sets bootfs property of the POOL. > > bootfs property contains object number of active dataset object. > > During bootup gptzfsboot probes all the disks, creating SPA for any > > valid pool. gptzfsboot assumes the first pool it finds as a primary > > pool, it then reads meta object set, then tries to find object nunber > > of active dataset object either through > > a. bootfs - it would be set if BE was already created > > b. mos->properties_zap->root_dataset->dd_head_dataset_obj (through > > root_datasets bonus buffer) > > Once the object number is obtaind gptzfsboot mounts the dataset. > > > > After mounting, few files are looked up like /boot/config or > > /boot.config for presense of boot command (did not went into details > > of this). Then (if keyboard is not hit), gptzfsboot execs > > /boot/zfsloader. If gptzfsboot is interrupted by keyboard, then it > > displays default BE or POOL it is trying to boot from (using > > zfs_rlookup() to map active dataset object to string BE name). Though > > I haven't checked this but through serial console user would be > > allowed to enter other pool or BE to boot from. > > > > I could not go into details of how gptzfsboot reads /boot/zfsloader from > disk. > > > > Pending Tasks > > ============= > > 1. Understand upon keyboard interruption, how user entered zfs paths > > (format [zfs:pool/filesystem:][/path/to/loader]) are converted in > > object numbers? > > 2. Learn ZFS on disk format in more details so as to identify active > > dataset object numbers of all BEs. Once the object numbers are > > available, I can use zfs_rlookup() function to map object number to > > printable pool name. > > 3. Prepare library for console based menu. > > > > Plan for next week > > ================== > > Pending task 2 above >
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