Thanks Alasdair and Neil,
Alasdair G Kergon wrote:
Test with trees of devices too - where a whole tree is suspended -
Suspending maps in the tree and reload one of them?
I'll try that.
I don't think you can allocate anywhere in dm_swap_table()
without PF_MEMALLOC (which I recently removed and am reluctant
to reinstate).
I understand your reluctance and I don't want to revive it either.
I think moving sysfs_add_link() outside of dm_swap_table() solves
this. Am I right?
Or do you want to eliminate the possibility that sysfs_remove_symlink()
may require memory allocation in future?
Anyway, I'll seek for bd_claim based approach.
Have you considered if anything is feasible based around bd_claim()?
Doesn't it make more sense for the links to be set up at table
load time - i.e. superset of both tables if present?
I think it makes sense. But I have difficulty with it.
What I once thought was extending bd_claim() like:
bd_claim_with_owner(bdev, void *holder, struct kobject *owner)
where "owner" is a kobject for "slaves" directory.
We may have the object embedded in gendisk structure.
Then we can create symlinks like:
/sys/block/<bdev>/holders/<owner> --> /sys/block/<owner>
/sys/block/<owner>/slaves/<bdev> --> /sys/block/<bdev>
This should work for md.
However, dm needs more for its flexibility.
Because multiple dm devices can hold one device and one dm device
can hold a device twice (i.e. current table and new table),
we need to reference-count per relationship basis, not per slave
device.
This might be solved by allocating management struct in bd_claim()
to reference-counting the relationship.
I'll try this. Comments are welcome.
--
Jun'ichi Nomura, NEC Solutions (America), Inc.
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[Index of Archives]
[Kernel Newbies]
[Netfilter]
[Bugtraq]
[Photo]
[Stuff]
[Gimp]
[Yosemite News]
[MIPS Linux]
[ARM Linux]
[Linux Security]
[Linux RAID]
[Video 4 Linux]
[Linux for the blind]
[Linux Resources]
