Ext4 Developer Interlock Call: 04/23/2007 Meeting Minutes
Attendees: Mingming Cao, Dave Kleikamp, Avantika Mathur, Ted Ts'o,
Suparna Bhattacharya,
Jean-Pierre Dion, Jean Noel Cordenner, Valérie Clément, Jose Santos
Minutes can be accessed at:
http://ext4.wiki.kernel.org/index.php/Ext4_Developer%27s_Conference_Call
- Mingming proposed moving back to 8am PST meeting time, since the 6am
time is inconvenient for
a few people. This discussion will be continued through email, to find
a time which works
for everyone.
- Next week's meeting will be canceled, unless there is anyone who would
like to request a meeting.
PATCH STATUS
git-tree
- Mingming will be updating the git tree with extents-fix patches from
Alex, i_flags patch from Honza, i_extra_isize patch from Kalpak.
Uninitialized Block Groups:
- The patch sent out by Andreas is against 2.6.16 and ext3. Need to
port this to current ext4, test and then add to git-tree. Avantika will
ask Andreas if he needs help with this.
JBD statistics:
- There is a patch to export JDB statistics to /proc. In order to get
this patch to mainline, there needs to be discussion about the correct
place for the statistics; /proc or perhaps debugfs.
e2fsprogs:
- Ted will post the current e2fsprogs patches in progress. Ted has been
working with these patches and making changes.
- Main work areas for making e2fsprogs compatible with extents and 64-bit.
- block iterator: make a block iterator work with both extent and
non-extent code. Code that is oblivious to extents will still work with
the block iterator. This has been written by Andreas Dilger.
- extents: in order to preserve ABI compatibility, support for a new
interface for extents which uses 64-bit logical and physical block
numbers. The block iterator then translate from on-disk to in-memory
format. This will allow for possible future increases of physical and
logical block sizes in extents, without breaking ABI.
- bitmaps in e2fsprogs: this will be discussed in more detail at the
next meeting, after people have a chance to read related email.
preallocation:
- fallocate syscall interface: the current plan, based on discussions
on the mailing list, is to create a separate wrapper for s390 in glibc.
Using regular parameter ordering for all other architectures, but a
different order on s390. Jakub Jelinek has said that the changes in
glibc can be made pretty easily.
- The preallocation patches in the ext4 git-tree are outdated, using
the ioctl interface. Once Amit re-posts the patches with the syscall
interface, they will be updated in the git-tree as well.
- Mingming mentioned the need to flush preallocation metadata changes to
disk if file size or file content is being tested. Discussed doing an
fsync at Bmap time.
TESTING
- extents testing
- Discussed methods for testing extents on highly fragmented
filesystems.
- Jose will look into possible tests, including perhaps using the
'aged' option in FFSB
- Ted suggested creating a mountoption that creates a bad block
allocator which it jumps to a new block group every 8 blocks. This
would force a very large number of extents, and may be a good test for
extents.
- large filesystem
- We would like to perform more testing on large (>16TB) filesystems
- currently hardware limitations are preventing this testing. We
have tested 10TB raid dists, and 16TB loopback devices. Avantika will
look into creating very large sparse devices for testing.
- Large file deletion
- Valerie had recently tested large file deletion on ext3/4, but did
not see the expected performance gain with ext4 due to compact metadata
when using extents.
- Valerie will try re-running the test. Jose will also be looking
into this test.
-
To unsubscribe from this list: send the line "unsubscribe linux-ext4" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
