On 2016/06/12 at 13:16, Xunlei Pang wrote:
On 2016/06/12 at 12:01, Xunlei Pang wrote:
On 2016/06/12 at 10:35, Dave Young wrote:
On 06/12/16 at 10:05am, Xunlei Pang wrote:
On 2016/06/08 at 10:16, Dave Young wrote:
Hi, On 06/06/16 at 05:00pm, Xunlei Pang wrote:
On 2016/06/06 at 11:12, Dave Young wrote: > Hi Xunlei, > > On 06/06/16 at 10:43am, Xunlei Pang wrote: >> On 2016/06/06 at 09:55, Dave Young wrote: >>> On 06/06/16 at 09:01am, Xunlei Pang wrote: >>>> On 2016/06/02 at 16:48, Dave Young wrote: >>>>> On 06/02/16 at 04:21pm, Xunlei Pang wrote: >>>>>> On 2016/06/02 at 15:46, Dave Young wrote: >>>>>>> Hi, Xunlei >>>>>>> >>>>>>> Seems I sent wrong draft, here is the right one: >>>>>>> >>>>>>> Add a question about below >>>>>>> --add-driver "nfs nfsv4" >>>>>>> >>>>>>> Why should we add them? if we addes dracut 95nfs module then it will install >>>>>>> all the nfs kernel modules and network module. >>>>>> Yeah, dracut 95nfs module has >>>>>> installkernel() { >>>>>> instmods nfs sunrpc ipv6 nfsv2 nfsv3 nfsv4 nfs_acl nfs_layout_nfsv41_files >>>>>> } >>>>>> >>>>>> But actually during my test, I found that if nfs was not mounted, some of the modules >>>>>> (for example nfsv4)will fail to be installed by instmods. >>>>> Hmm, it may related to we use hostonly, could you check the instmods function >>>>> to see if we can handle it without adding drivers in dracut args? >>>> You're right, it's due to the hostonly dracut option, and it's not nfs-only, it's a common >>>> issue due to the target not mounted beforehand. >>>> >>>> Currently, I can't think of a nice way to handle it without adding drivers explicitly. >>> Does --force-add works? >> I doesn't work, the "nfs" dracut module is ok, it's the "instmods" in dracut's "nfs" that doesn't work. >> But with the other reply to specify the right "nfsv4" filesytem type, it should work for us. > If --force-add is meant to bypass hostonly then it should be extended to > also work in instmods then we can use force-add for these --mount so > that one do not need add extra kernel modules. "--force_add" affects check() in module_setup.sh.
For nfs, it is: # called by dracut check() { # If our prerequisites are not met, fail anyways. require_any_binary rpcbind portmap || return 1 require_binaries rpc.statd mount.nfs mount.nfs4 umount || return 1
[[ $hostonly ]] || [[ $mount_needs ]] && { for fs in "${host_fs_types[@]}"; do [[ "$fs" == "nfs" ]] && return 0 [[ "$fs" == "nfs3" ]] && return 0 [[ "$fs" == "nfs4" ]] && return 0 done return 255 } return 0}
so only affects the dracut modules to be added.
For nfs instmods, dracut handles it in installkernel(), it is: # called by dracut installkernel() { instmods nfs sunrpc ipv6 nfsv2 nfsv3 nfsv4 nfs_acl nfs_layout_nfsv41_files }
"The --force-add extension to instmods" will involve many dracut's fundamental changes.
So there are two problems here.
- --mount parsing and add nfs ko files in another reply
- --force-add only affects module check
For 1), the original logic about nfs module seems wrong. One can setup nfs4 in config files, but just use mount -t nfs, it will actually use nfs4 kernel module. (Need verification..). If I am right then in case mount_needs for nfs all nfs kernel module should be added.
The original design needs nfs to be mounted beforehand, although users can use "mount -t nfs" for nfs4, but findmnt will get the right "nfs4" fstype, also the related modules(nfsv4.ko) were loaded after the mount, so there is no problem for instmods to install "nfsv4,ko".
The current implementation of dracut: function inst1mod() { <snip> # If we are building a host-specific initramfs and this # module is not already loaded, move on to the next one. [[ $hostonly ]] \ && ! module_is_host_only "$_mod" \ && return 0
module_is_host_only() { local _mod=$1 local _modenc a i _k _s _v _aliases _mod=${_mod##*/} _mod=${_mod%.ko} _modenc=${_mod//-/_}
[[ " $add_drivers " == *\ ${_mod}\ * ]] && return 0 # check if module is loaded [[ ${host_modules["$_modenc"]} ]] && return 0Thus for $hostonly mode, it will fail to install any ko not loaded if not explicitly added via "--add-drivers".
I am not quite clear about "mount_needs" you mentioned, from the code it seems also to be only related to dracut's module check.
mount_needs is introduced for adding dracut modules for --mount needed, but yes it only handles dracut modules in check() function, it may need to extend to inst kernel modules.
OTOH, since we have mount_needs why do we need to add 95nfs dracut modules in kdump code? Shouldn't it been added via mount_needs check?
Yes, agree, I think kdump needn't add "nfs" dracut module explicitly. The check_mount should be able to add it properly for us, as we have nfs "--mount" info, the host_fs_types[] will contain the "nfs*" fstype.
Another issue is we may need use force_add because we are using hostonly mode along with mount_needs, we can not use mount_needs but without respecting hostonly for adding non-hostonly kernel modules.. So we should still force add 95nfs dracut modules in out code and extend force add to unset hostonly during handling kernel modules. It make sense because force-add already do that in module check functions it has already unset hostonly that means it has higer priority than hostonly.
force_add is semantically better for the purpose of this patch, but OTOH this patch actually doesn't only deal with nfs, it's for a general purpose "--mount".
So I would rather rely on mount_needs to force "instmods".
From my tests, unlike nfsv4, nfs/ext[234]/xfs can work properly, becasue in 90kernel-modules/module-setup.sh installkernel(): for i in $(host_fs_all); do hostonly='' instmods $i done
So for these fstypes, they have a valid mapping (or same) name to their ko names, say "xfs.ko" for "xfs", "ext4.ko" for "ext3", and they can be handled properly(as hostonly was unset).
But for fstype "nfs[2-4]", its ko is "nfsv[2-4].ko", if we do a mapping like discussed previously, tests show it can work properly:
for i in $(host_fs_all); do
if [[ $i = nfs[2-4] ]]; theni=${i/nfs/nfsv}fi hostonly='' instmods $i doneThis will be a simple fix, and can omit explicitly kdump adding "nfs" dracut module for all cases.
From "man nfs" : The fstype field contains "nfs". Use of the "nfs4" fstype in /etc/fstab is deprecated. So I guess we can add all related ko modules for "nfs" fstype here, like the patch below?
for i in $(host_fs_all); do + if [[ $i = nfs ]]; then + # From "man nfs": The fstype field contains "nfs". Use of the "nfs4" fstype in /etc/fstab is deprecated. + # For "nfs" fstype, we better install all the possible ko modules(from 95nfs/module-setup.sh installkernel). + i="nfs sunrpc ipv6 nfsv2 nfsv3 nfsv4 nfs_acl nfs_layout_nfsv41_files" + elif [[ $i = nfs[3-4] ]]; then + # For example, map nfs4 to use nfsv4.ko + i=${i/nfs/nfsv} + fi hostonly='' instmods $i done
Or, if it is not acceptable on dracut's side, we can add "--add-drivers" for "nfs sunrpc ipv6 nfsv2 nfsv3 nfsv4 nfs_acl nfs_layout_nfsv41_files" in kdump code in this patch like that in the early versions, any comment?
Regards, Xunlei