В Sun, 19 Apr 2015 22:53:35 +0300
Toomas Soome <tso...@me.com> пишет:
>
> > On 19.04.2015, at 22:40, Andrei Borzenkov <arvidj...@gmail.com> wrote:
> >
> > В Thu, 16 Apr 2015 08:24:38 +0300
> > Toomas Soome <tso...@me.com> пишет:
> >
> >>
> >
> > Could you explain how these changes affect large block read? As far as
> > I understand, this feature is basically "for free" - changes were
> > needed to allow large block writes, but on disk format already
> > supported them so reading should have just worked?
> >
>
>
> yes, large block is basically free, but, there are 2 conditions.
>
> 1. large blocks basically use extensible dataset feature, or to be exact,
> setting recordsize above 128k will trigger large_block feature to be enabled
> and storing such blocks is using feature extensible dataset. so the
> extensible dataset is prerequisite.
>
> 2. once large block is enabled, its listed in label as well, and therefore it
> should be listed in spa_feature_names, which is list of supported features.
>
> but otherwise, reading large blocks does not require any other changes
> (assuming there is enough memory to read those blocks).
Good. So the means that the only change needed was ...
>
> rgds,
> toomas
>
>
>
> >> ---
> >> grub-core/fs/zfs/zfs.c | 18 +++++++++++-------
> >> 1 file changed, 11 insertions(+), 7 deletions(-)
> >>
> >> diff --git a/grub-core/fs/zfs/zfs.c b/grub-core/fs/zfs/zfs.c
> >> index da44131..4a542e0 100644
> >> --- a/grub-core/fs/zfs/zfs.c
> >> +++ b/grub-core/fs/zfs/zfs.c
> >> @@ -283,6 +283,8 @@ static const char *spa_feature_names[] = {
> >> "org.illumos:lz4_compress",
> >> "com.delphix:hole_birth",
> >> "com.delphix:embedded_data",
> >> + "com.delphix:extensible_dataset",
> >> + "org.open-zfs:large_blocks",
... this one. What all other changes below do and how they are related
to these two features?
> >> NULL
> >> };
> >>
> >> @@ -3080,7 +3082,7 @@ get_filesystem_dnode (dnode_end_t * mosmdn, char
> >> *fsname,
> >>
> >> grub_dprintf ("zfs", "alive\n");
> >>
> >> - err = dnode_get (mosmdn, objnum, DMU_OT_DSL_DIR, mdn, data);
> >> + err = dnode_get (mosmdn, objnum, 0, mdn, data);
> >> if (err)
> >> return err;
> >>
> >> @@ -3113,7 +3115,7 @@ get_filesystem_dnode (dnode_end_t * mosmdn, char
> >> *fsname,
> >> if (err)
> >> return err;
> >>
> >> - err = dnode_get (mosmdn, objnum, DMU_OT_DSL_DIR, mdn, data);
> >> + err = dnode_get (mosmdn, objnum, 0, mdn, data);
> >> if (err)
> >> return err;
> >>
> >> @@ -3268,8 +3270,7 @@ dnode_get_fullpath (const char *fullpath, struct
> >> subvolume *subvol,
> >>
> >> grub_dprintf ("zfs", "endian = %d\n", subvol->mdn.endian);
> >>
> >> - err = dnode_get (&(data->mos), headobj, DMU_OT_DSL_DATASET,
> >> &subvol->mdn,
> >> - data);
> >> + err = dnode_get (&(data->mos), headobj, 0, &subvol->mdn, data);
> >> if (err)
> >> {
> >> grub_free (fsname);
> >> @@ -3665,8 +3666,11 @@ zfs_mount (grub_device_t dev)
> >> if (ub->ub_version >= SPA_VERSION_FEATURES &&
> >> check_mos_features(&((objset_phys_t *) osp)->os_meta_dnode,ub_endian,
> >> data) != 0)
> >> - return NULL;
> >> -
> >> + {
> >> + grub_error (GRUB_ERR_BAD_FS, "Unsupported features in pool");
> >> + return NULL;
> >> + }
> >> +
> >> /* Got the MOS. Save it at the memory addr MOS. */
> >> grub_memmove (&(data->mos.dn), &((objset_phys_t *) osp)->os_meta_dnode,
> >> DNODE_SIZE);
> >> @@ -3963,7 +3967,7 @@ fill_fs_info (struct grub_dirhook_info *info,
> >> {
> >> headobj = grub_zfs_to_cpu64 (((dsl_dir_phys_t *) DN_BONUS
> >> (&mdn.dn))->dd_head_dataset_obj, mdn.endian);
> >>
> >> - err = dnode_get (&(data->mos), headobj, DMU_OT_DSL_DATASET, &mdn,
> >> data);
> >> + err = dnode_get (&(data->mos), headobj, 0, &mdn, data);
> >> if (err)
> >> {
> >> grub_dprintf ("zfs", "failed here\n");
> >
>
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