In preparation for the next patch, the function ext4_add_groupblocks()
is moved to mballoc.c, where it could use some static functions.
Signed-off-by: Amir Goldstein <amir73il@users.sf.net>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
There is already an #ifdef CONFIG_QUOTA some lines above,
so this one is totally useless.
Signed-off-by: WANG Cong <amwang@redhat.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
We have checked first_not_zeroed == ngroups already above, so remove
this redundant check.
sbi->s_li_request = NULL above is also removed since it is NULL
already.
Cc: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: Tao Ma <boyu.mt@taobao.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
In __ext4_get_inode_loc, we calculate inodes_per_block every time by
EXT4_BLOCK_SIZE(sb) / EXT4_INODE_SIZE(sb). AFAICS, this function is a
hot path for ext4, so we'd better use s_inodes_per_block directly
instead of calculating every time.
Signed-off-by: Tao Ma <boyu.mt@taobao.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
We have EXT4FS_DEBUG for some old debug and CONFIG_EXT4_DEBUG
for the new mballoc debug, but there isn't any EXT4_DEBUG.
As CONFIG_EXT4_DEBUG seems to be only used in mballoc, use
EXT4FS_DEBUG in fsync.c.
[ It doesn't really matter; although I'm including this commit for
consistency's sake. The whole point of the #ifdef's is to disable
the debugging code. In general you're not going to want to enable
all of the code protected by EXT4FS_DEBUG at the same time. -- Ted ]
Signed-off-by: Tao Ma <boyu.mt@taobao.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Add two functions: ext4_split_extent_at(), which splits an extent into
two extents at given logical block, and ext4_split_extent() which
splits an extent into three extents.
Signed-off-by: Yongqiang Yang <xiaoqiangnk@gmail.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Tested-by: Allison Henderson <achender@linux.vnet.ibm.com>
1) Rename ext4_ext_try_to_merge() to ext4_ext_try_to_merge_right().
2) Add a new function ext4_ext_try_to_merge() which tries to merge
an extent both left and right.
3) Use the new function in ext4_ext_convert_unwritten_endio() and
ext4_ext_insert_extent().
Signed-off-by: Yongqiang Yang <xiaoqiangnk@gmail.com>
Tested-by: Allison Henderson <achender@linux.vnet.ibm.com>
ext4_symlink() cannot call __page_symlink() with transaction open.
__page_symlink() calls ext4_write_begin() which can wait for
transaction commit if we are running out of space thus causing a
deadlock. Also error recovery in ext4_truncate_failed_write() does not
count with the transaction being already started (although I'm not
aware of any particular deadlock here).
Fix the problem by stopping a transaction before calling
__page_symlink() (we have to be careful and put inode to orphan list
so that it gets deleted in case of crash) and starting another one
after __page_symlink() returns for addition of symlink into a
directory.
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
When make_indexed_dir() fails (e.g. because of ENOSPC) after it has
allocated block for index tree root, we did not properly mark all
changed buffers dirty. This lead to only some of these buffers being
written out and thus effectively corrupting the directory.
Fix the issue by marking all changed data dirty even in the error
failure case.
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Fix a typo that was introduced in commit 07a038245b (in 2.6.36) which
caused the extents flag not to be set at the conclusion of converting
an inode to use extents.
Reported-by: Peter Uchno <peter.uchno@gmail.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
percpu_counter_sum_positive() never returns a negative value.
Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
This is an effective revert of commit a30eec2a8: "ext4: stop issuing
discards if not supported by device". The problem is that there are
some devices that may return errors in response to a discard request
some times but not others. (One example would be a hybrid dm device
which concatenates an SSD and an HDD device).
By this logic, I also removed the error checking from ext4's FITRIM
code; so that an error from a discard will not stop the FITRIM from
trying to trim the rest of the file system.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
In the bio completion routine, we should not be setting
PageUptodate at all -- it's set at sys_write() time, and is
unaffected by success/failure of the write to disk.
This can cause a page corruption bug when the file system's
block size is less than the architecture's VM page size.
if we have only written a single block -- we might end up
setting the page's PageUptodate flag, indicating that page
is completely read into memory, which may not be true.
This could cause subsequent reads to get bad data.
This commit also takes the opportunity to clean up error
handling in ext4_end_bio(), and remove some extraneous code:
- fixes ext4_end_bio() to set AS_EIO in the
page->mapping->flags on error, which was left out by
mistake. This is needed so that fsync() will
return an error if there was an I/O error.
- remove the clear_buffer_dirty() call on unmapped
buffers for each page.
- consolidate page/buffer error handling in a single
section.
Signed-off-by: Curt Wohlgemuth <curtw@google.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Reported-by: Jim Meyering <jim@meyering.net>
Reported-by: Hugh Dickins <hughd@google.com>
Cc: Mingming Cao <cmm@us.ibm.com>
Provide better emulation for ext[23] mode by enforcing that the file
system does not have any unsupported file system features as defined
by ext[23] when emulating the ext[23] file system driver when
CONFIG_EXT4_USE_FOR_EXT23 is defined.
This causes the file system type information in /proc/mounts to be
correct for the automatically mounted root file system. This also
means that "mount -t ext2 /dev/sda /mnt" will fail if /dev/sda
contains an ext3 or ext4 file system, just as one would expect if the
original ext2 file system driver were in use.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Add missing page_cache_release in the error path of ext4_mb_load_buddy
Signed-off-by: Yang Ruirui <ruirui.r.yang@tieto.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: stable@kernel.org
* 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4:
ext4: fix data corruption regression by reverting commit 6de9843dab
ext4: Allow indirect-block file to grow the file size to max file size
ext4: allow an active handle to be started when freezing
ext4: sync the directory inode in ext4_sync_parent()
ext4: init timer earlier to avoid a kernel panic in __save_error_info
jbd2: fix potential memory leak on transaction commit
ext4: fix a double free in ext4_register_li_request
ext4: fix credits computing for indirect mapped files
ext4: remove unnecessary [cm]time update of quota file
jbd2: move bdget out of critical section
Revert commit 6de9843dab, since it
caused a data corruption regression with BitTorrent downloads. Thanks
to Damien for discovering and bisecting to find the problem commit.
https://bugzilla.kernel.org/show_bug.cgi?id=32972
Reported-by: Damien Grassart <damien@grassart.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
We can create 4402345721856 byte file with indirect block mapping.
However, if we grow an indirect-block file to the size with ftruncate(),
we can see an ext4 warning. The following patch fixes this problem.
How to reproduce:
# dd if=/dev/zero of=/mnt/mp1/hoge bs=1 count=0 seek=4402345721856
0+0 records in
0+0 records out
0 bytes (0 B) copied, 0.000221428 s, 0.0 kB/s
# tail -n 1 /var/log/messages
Nov 25 15:10:27 test kernel: EXT4-fs warning (device sda8): ext4_block_to_path:345: block 1074791436 > max in inode 12
Signed-off-by: Kazuya Mio <k-mio@sx.jp.nec.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
ext4_journal_start_sb() should not prevent an active handle from being
started due to s_frozen. Otherwise, deadlock is easy to happen, below
is a situation.
================================================
freeze | truncate
================================================
| ext4_ext_truncate()
freeze_super() | starts a handle
sets s_frozen |
| ext4_ext_truncate()
| holds i_data_sem
ext4_freeze() |
waits for updates |
| ext4_free_blocks()
| calls dquot_free_block()
|
| dquot_free_blocks()
| calls ext4_dirty_inode()
|
| ext4_dirty_inode()
| trys to start an active
| handle
|
| block due to s_frozen
================================================
Signed-off-by: Yongqiang Yang <xiaoqiangnk@gmail.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Reported-by: Amir Goldstein <amir73il@users.sf.net>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
ext4 has taken the stance that, in the absence of a journal,
when an fsync/fdatasync of an inode is done, the parent
directory should be sync'ed if this inode entry is new.
ext4_sync_parent(), which implements this, does indeed sync
the dirent pages for parent directories, but it does not
sync the directory *inode*. This patch fixes this.
Also now return error status from ext4_sync_parent().
I tested this using a power fail test, which panics a
machine running a file server getting requests from a
client. Without this patch, on about every other test run,
the server is missing many, many files that had been synced.
With this patch, on > 6 runs, I see zero files being lost.
Google-Bug-Id: 4179519
Signed-off-by: Curt Wohlgemuth <curtw@google.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
During mount, when we fail to open journal inode or root inode, the
__save_error_info will mod_timer. But actually s_err_report isn't
initialized yet and the kernel oops. The detailed information can
be found https://bugzilla.kernel.org/show_bug.cgi?id=32082.
The best way is to check whether the timer s_err_report is initialized
or not. But it seems that in include/linux/timer.h, we can't find a
good function to check the status of this timer, so this patch just
move the initializtion of s_err_report earlier so that we can avoid
the kernel panic. The corresponding del_timer is also added in the
error path.
Reported-by: Sami Liedes <sliedes@cc.hut.fi>
Signed-off-by: Tao Ma <boyu.mt@taobao.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
In ext4_register_li_request, we malloc a ext4_li_request and
inserts it into ext4_li_info->li_request_list. In case of any
error later, we free it in the end. But if we have some error
in ext4_run_lazyinit_thread, the whole li_request_list will be
dropped and freed in it. So we will double free this ext4_li_request.
This patch just sets elr to NULL after it is inserted to the list
so that the latter kfree won't double free it.
Signed-off-by: Tao Ma <boyu.mt@taobao.com>
Reviewed-by: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: stable@kernel.org
When writing a contiguous set of blocks, two indirect blocks could be
needed depending on how the blocks are aligned, so we need to increase
the number of credits needed by one.
[ Also fixed a another bug which could further underestimate the
number of journal credits needed by 1; the code was using integer
division instead of DIV_ROUND_UP() -- tytso]
Signed-off-by: Yongqiang Yang <xiaoqiangnk@gmail.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: stable@kernel.org
It is not necessary to update [cm]time of quota file on each quota
file write and it wastes journal space and IO throughput with inode
writes. So just remove the updating from ext4_quota_write() and only
update times when quotas are being turned off. Userspace cannot get
anything reliable from quota files while they are used by the kernel
anyway.
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
* 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (43 commits)
ext4: fix a BUG in mb_mark_used during trim.
ext4: unused variables cleanup in fs/ext4/extents.c
ext4: remove redundant set_buffer_mapped() in ext4_da_get_block_prep()
ext4: add more tracepoints and use dev_t in the trace buffer
ext4: don't kfree uninitialized s_group_info members
ext4: add missing space in printk's in __ext4_grp_locked_error()
ext4: add FITRIM to compat_ioctl.
ext4: handle errors in ext4_clear_blocks()
ext4: unify the ext4_handle_release_buffer() api
ext4: handle errors in ext4_rename
jbd2: add COW fields to struct jbd2_journal_handle
jbd2: add the b_cow_tid field to journal_head struct
ext4: Initialize fsync transaction ids in ext4_new_inode()
ext4: Use single thread to perform DIO unwritten convertion
ext4: optimize ext4_bio_write_page() when no extent conversion is needed
ext4: skip orphan cleanup if fs has unknown ROCOMPAT features
ext4: use the nblocks arg to ext4_truncate_restart_trans()
ext4: fix missing iput of root inode for some mount error paths
ext4: make FIEMAP and delayed allocation play well together
ext4: suppress verbose debugging information if malloc-debug is off
...
Fi up conflicts in fs/ext4/super.c due to workqueue changes
* 'for-2.6.39/core' of git://git.kernel.dk/linux-2.6-block: (65 commits)
Documentation/iostats.txt: bit-size reference etc.
cfq-iosched: removing unnecessary think time checking
cfq-iosched: Don't clear queue stats when preempt.
blk-throttle: Reset group slice when limits are changed
blk-cgroup: Only give unaccounted_time under debug
cfq-iosched: Don't set active queue in preempt
block: fix non-atomic access to genhd inflight structures
block: attempt to merge with existing requests on plug flush
block: NULL dereference on error path in __blkdev_get()
cfq-iosched: Don't update group weights when on service tree
fs: assign sb->s_bdi to default_backing_dev_info if the bdi is going away
block: Require subsystems to explicitly allocate bio_set integrity mempool
jbd2: finish conversion from WRITE_SYNC_PLUG to WRITE_SYNC and explicit plugging
jbd: finish conversion from WRITE_SYNC_PLUG to WRITE_SYNC and explicit plugging
fs: make fsync_buffers_list() plug
mm: make generic_writepages() use plugging
blk-cgroup: Add unaccounted time to timeslice_used.
block: fixup plugging stubs for !CONFIG_BLOCK
block: remove obsolete comments for blkdev_issue_zeroout.
blktrace: Use rq->cmd_flags directly in blk_add_trace_rq.
...
Fix up conflicts in fs/{aio.c,super.c}
And give it a kernel-doc comment.
[akpm@linux-foundation.org: btrfs changed in linux-next]
Signed-off-by: Serge E. Hallyn <serge.hallyn@canonical.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Daniel Lezcano <daniel.lezcano@free.fr>
Acked-by: David Howells <dhowells@redhat.com>
Cc: James Morris <jmorris@namei.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
As a preparation for removing ext2 non-atomic bit operations from
asm/bitops.h. This converts ext2 non-atomic bit operations to
little-endian bit operations.
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Acked-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The map_bh() call will have already set the buffer_head to mapped.
Signed-off-by: Feng Tang <feng.tang@intel.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
- Add more ext4 tracepoints.
- Change ext4 tracepoints to use dev_t field with MAJOR/MINOR macros
so that we can save 4 bytes in the ring buffer on some platforms.
- Add sync_mode to ext4_da_writepages, ext4_da_write_pages, and
ext4_da_writepages_result tracepoints. Also remove for_reclaim
field from ext4_da_writepages since it is usually not very useful.
Signed-off-by: Jiaying Zhang <jiayingz@google.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
We can call kfree on uninitialized members of the s_group_info array
on an the error path. We can avoid this by kzalloc'ing the array.
This doesn't entirely solve the oops on mount if we fail down this
path; failed_mount4: frees the sbi, for one, which gets referenced
later in the failed mount paths - I haven't worked that out yet.
https://bugzilla.kernel.org/show_bug.cgi?id=30872
Reported-by: Eugene A. Shatokhin <dame_eugene@mail.ru>
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
When we do performence-testing on ext4 filesystem, we observed a
warning like this:
EXT4-fs error (device sda7): ext4_mb_generate_buddy:718: group 259825901 blocks in bitmap, 26057 in gd
instead, it should be
"group 2598, 25901 blocks in bitmap, 26057 in gd"
Reviewed-by: Coly Li <bosong.ly@taobao.com>
Cc: Tao Ma <boyu.mt@taobao.com>
Signed-off-by: Robin Dong <sanbai@taobao.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
FITRIM isn't added in compat_ioctl. So a 32 bit program can't be executed
in a 64 bit platform. Add it in the compat_ioctl.
Signed-off-by: Tao Ma <boyu.mt@taobao.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Checking return code from ext4_journal_get_write_access() is important
with snapshots, because this function invokes COW, so may return new
errors, such as ENOSPC.
ext4_clear_blocks() now returns < 0 for fatal errors, in which case,
ext4_free_data() is aborted.
Signed-off-by: Amir Goldstein <amir73il@users.sf.net>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
There are two wrapper functions which do exactly the same thing:
ext4_journal_release_buffer(), and ext4_handle_release_buffer(). In
addition, ext4_xattr_block_set() calls jbd2_journal_release_buffer()
directly.
Unify all of the code to use ext4_handle_release_buffer(), and get rid
of ext4_journal_release_buffer().
Signed-off-by: Amir Goldstein <amir73il@users.sf.net>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Checking return code from ext4_journal_get_write_access() is important
with snapshots, because this function invokes COW, so may return new
errors, such as ENOSPC.
We move the call to ext4_journal_get_write_access earlier in the
function, to simplify error handling in the case that this function
returns returns an error.
Signed-off-by: Amir Goldstein <amir73il@users.sf.net>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (47 commits)
doc: CONFIG_UNEVICTABLE_LRU doesn't exist anymore
Update cpuset info & webiste for cgroups
dcdbas: force SMI to happen when expected
arch/arm/Kconfig: remove one to many l's in the word.
asm-generic/user.h: Fix spelling in comment
drm: fix printk typo 'sracth'
Remove one to many n's in a word
Documentation/filesystems/romfs.txt: fixing link to genromfs
drivers:scsi Change printk typo initate -> initiate
serial, pch uart: Remove duplicate inclusion of linux/pci.h header
fs/eventpoll.c: fix spelling
mm: Fix out-of-date comments which refers non-existent functions
drm: Fix printk typo 'failled'
coh901318.c: Change initate to initiate.
mbox-db5500.c Change initate to initiate.
edac: correct i82975x error-info reported
edac: correct i82975x mci initialisation
edac: correct commented info
fs: update comments to point correct document
target: remove duplicate include of target/target_core_device.h from drivers/target/target_core_hba.c
...
Trivial conflict in fs/eventpoll.c (spelling vs addition)
When allocating a new inode, we need to make sure i_sync_tid and
i_datasync_tid are initialized. Otherwise, one or both of these two
values could be left initialized to zero, which could potentially
result in BUG_ON in jbd2_journal_commit_transaction.
(This could happen by having journal->commit_request getting set to
zero, which could wake up the kjournald process even though there is
no running transaction, which then causes a BUG_ON via the
J_ASSERT(j_ruinning_transaction != NULL) statement.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/security-testing-2.6: (33 commits)
AppArmor: kill unused macros in lsm.c
AppArmor: cleanup generated files correctly
KEYS: Add an iovec version of KEYCTL_INSTANTIATE
KEYS: Add a new keyctl op to reject a key with a specified error code
KEYS: Add a key type op to permit the key description to be vetted
KEYS: Add an RCU payload dereference macro
AppArmor: Cleanup make file to remove cruft and make it easier to read
SELinux: implement the new sb_remount LSM hook
LSM: Pass -o remount options to the LSM
SELinux: Compute SID for the newly created socket
SELinux: Socket retains creator role and MLS attribute
SELinux: Auto-generate security_is_socket_class
TOMOYO: Fix memory leak upon file open.
Revert "selinux: simplify ioctl checking"
selinux: drop unused packet flow permissions
selinux: Fix packet forwarding checks on postrouting
selinux: Fix wrong checks for selinux_policycap_netpeer
selinux: Fix check for xfrm selinux context algorithm
ima: remove unnecessary call to ima_must_measure
IMA: remove IMA imbalance checking
...
* 'for-2.6.39' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq:
workqueue: fix build failure introduced by s/freezeable/freezable/
workqueue: add system_freezeable_wq
rds/ib: use system_wq instead of rds_ib_fmr_wq
net/9p: replace p9_poll_task with a work
net/9p: use system_wq instead of p9_mux_wq
xfs: convert to alloc_workqueue()
reiserfs: make commit_wq use the default concurrency level
ocfs2: use system_wq instead of ocfs2_quota_wq
ext4: convert to alloc_workqueue()
scsi/scsi_tgt_lib: scsi_tgtd isn't used in memory reclaim path
scsi/be2iscsi,qla2xxx: convert to alloc_workqueue()
misc/iwmc3200top: use system_wq instead of dedicated workqueues
i2o: use alloc_workqueue() instead of create_workqueue()
acpi: kacpi*_wq don't need WQ_MEM_RECLAIM
fs/aio: aio_wq isn't used in memory reclaim path
input/tps6507x-ts: use system_wq instead of dedicated workqueue
cpufreq: use system_wq instead of dedicated workqueues
wireless/ipw2x00: use system_wq instead of dedicated workqueues
arm/omap: use system_wq in mailbox
workqueue: use WQ_MEM_RECLAIM instead of WQ_RESCUER
File system UUID is made available to application
via /proc/<pid>/mountinfo
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Now that VFS check for inode->i_nlink == 0 and returns proper
error, remove similar check from file system
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
With the plugging now being explicitly controlled by the
submitter, callers need not pass down unplugging hints
to the block layer. If they want to unplug, it's because they
manually plugged on their own - in which case, they should just
unplug at will.
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
Code has been converted over to the new explicit on-stack plugging,
and delay users have been converted to use the new API for that.
So lets kill off the old plugging along with aops->sync_page().
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
While running ext4 testing on multiple core, we found there are per
cpu ext4-dio-unwritten threads processing conversion from unwritten
extents to written for IOs completed from async direct IO patch. Per
filesystem is enough, we don't need per cpu threads to work on
conversion.
Signed-off-by: Mingming Cao <cmm@us.ibm.com>
