Commit Graph

88455 Commits

Author SHA1 Message Date
Jeff Mahoney
409753bf6d ocfs2/cluster: Get rid of arguments to the timeout routines
We keep seeing bug reports related to NULL pointer derefs in
o2net_set_nn_state(). When I originally wrote up the configurable timeout
patch, I had tried to plan for multiple clusters. This was silly.

The timeout routines all use o2nm_single_cluster so there's no point in
passing an argument at all. This patch removes the arguments and kills those
bugs dead.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-04-18 08:56:12 -07:00
Joel Becker
dda47bce91 ocfs2: Put tree in MAINTAINERS
The ocfs2 MAINTAINERS entry should have the git tree URL.

Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-04-18 08:56:11 -07:00
Julia Lawall
b1f3550fa1 ocfs2: Use BUG_ON
if (...) BUG(); should be replaced with BUG_ON(...) when the test has no
side-effects to allow a definition of BUG_ON that drops the code completely.

The semantic patch that makes this change is as follows:
(http://www.emn.fr/x-info/coccinelle/)

// <smpl>
@ disable unlikely @ expression E,f; @@

(
  if (<... f(...) ...>) { BUG(); }
|
- if (unlikely(E)) { BUG(); }
+ BUG_ON(E);
)

@@ expression E,f; @@

(
  if (<... f(...) ...>) { BUG(); }
|
- if (E) { BUG(); }
+ BUG_ON(E);
)
// </smpl>

Signed-off-by: Julia Lawall <julia@diku.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-04-18 08:56:11 -07:00
Andi Kleen
c9ec14884d ocfs2: Convert ocfs2 over to unlocked_ioctl
As far as I can see there is nothing in ocfs2_ioctl that requires the BKL,
so use unlocked_ioctl

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-04-18 08:56:11 -07:00
Jan Kara
5dabd69515 ocfs2: Improve rename locking
ocfs2_rename() was being too aggressive with the rename lock - we only need
it for certain forms of directory rename.

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-04-18 08:56:11 -07:00
Julia Lawall
58dadcdbc2 fs/ocfs2/aops.c: test for IS_ERR rather than 0
The function ocfs2_start_trans always returns either a valid pointer or a
value made with ERR_PTR, so its result should be tested with IS_ERR, not
with a test for 0.

Signed-off-by: Julia Lawall <julia@diku.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-04-18 08:56:11 -07:00
Tao Ma
4d0ddb2ce2 ocfs2: Add inode stealing for ocfs2_reserve_new_inode
Inode allocation is modified to look in other nodes allocators during
extreme out of space situations. We retry our own slot when space is freed
back to the global bitmap, or whenever we've allocated more than 1024 inodes
from another slot.

Signed-off-by: Tao Ma <tao.ma@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-04-18 08:56:10 -07:00
Tao Ma
a4a4891164 ocfs2: Add ac_alloc_slot in ocfs2_alloc_context
In inode stealing, we no longer restrict the allocation to
happen in the local node. So it is neccessary for us to add
a new member in ocfs2_alloc_context to indicate which slot
we are using for allocation. We also modify the process of
local alloc so that this member can be used there also.

Signed-off-by: Tao Ma <tao.ma@oracle.com>
Signed-off-by: Sunil Mushran <sunil.mushran@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-04-18 08:56:10 -07:00
Tao Ma
ffda89a3bf ocfs2: Add a new parameter for ocfs2_reserve_suballoc_bits
In some cases(Inode stealing from other nodes), we may not want
ocfs2_reserve_suballoc_bits to allocate new groups from the
global_bitmap since it may already be full. So add a new parameter
for this.

Signed-off-by: Tao Ma <tao.ma@oracle.com>
Signed-off-by: Sunil Mushran <sunil.mushran@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-04-18 08:56:10 -07:00
Tao Ma
ad5a4d7093 ocfs2: Enable cross extent block merge.
In ocfs2_figure_merge_contig_type, we judge whether there exists
a cross extent block merge and enable it by setting CONTIG_LEFT
and CONTIG_RIGHT accordingly.

Signed-off-by: Tao Ma <tao.ma@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-04-18 08:56:10 -07:00
Tao Ma
677b975282 ocfs2: Add support for cross extent block
In ocfs2_merge_rec_left, when we find the merge extent is "CONTIG_RIGHT"
with the first extent record of the next extent block, we will merge it to
the next extent block and change all the related extent blocks accordingly.

In ocfs2_merge_rec_right, when we find the merge extent is "CONTIG_LEFT"
with the last extent record of the previous extent block, we will merge
it to the prevoius extent block and change all the related extent blocks
accordingly.

As for CONTIG_LEFTRIGHT, we will handle CONTIG_RIGHT first so that when
the index is zero, the merge process will be more efficient and easier.

Signed-off-by: Tao Ma <tao.ma@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-04-18 08:56:10 -07:00
Mark Fasheh
52f7c21b61 ocfs2: Move /sys/o2cb to /sys/fs/o2cb
/sys/fs is where we really want file system specific sysfs objects.

Ocfs2-tools has been updated to look in /sys/fs/o2cb. We can maintain
backwards compatibility with old ocfs2-tools by using a sysfs symlink. After
some time (2 years), the symlink can be safely removed. This patch also adds
documentation to make it easier for people to figure out what /sys/fs/o2cb
is used for.

Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-04-18 08:56:10 -07:00
Mark Fasheh
a839c5afcd sysfs: Allow removal of symlinks in the sysfs root
Allow callers of sysfs_remove_link() to pass a NULL kobj, in which case
sysfs_root will be used as the parent directory. This allows us to tear down
top level symlinks created via sysfs_create_link(), which already has
similar handling of a NULL parent object.

Signed-off-by: Mark Fasheh <mfasheh@suse.com>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
2008-04-18 08:56:10 -07:00
Tao Ma
5cc3bf2786 ocfs2: Reconnect after idle time out.
Currently, o2net connects to a node on hb_up and disconnects on
hb_down and net timeout.

It disconnects on net timeout is ok, but it should attempt to
reconnect back. This is because sometimes nodes get overloaded
enough that the network connection breaks but the disk hb does not.
And if we get into that situation, we either fence (unnecessarily)
or wait for its disk hb to die (and sometimes hang in the process).

So in this updated scheme, when the network disconnects, we keep
attempting to reconnect till we succeed or we get a disk hb down
event.

If the other node is really dead, then we will eventually get a
node down event. If not, we should be able to connect again and
continue.

Signed-off-by: Tao Ma <tao.ma@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-04-18 08:56:10 -07:00
Sunil Mushran
8f50eb9789 ocfs2/dlm: Cleanup lockres print
A previous patch added KERN_NOTICE to printks printing the lockres that
cluttered the output. This patch removes the log level. For people concerned
with syslog clutter, please note we now use this facility to print lockres
only during an error.

Signed-off-by: Sunil Mushran <sunil.mushran@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-04-18 08:56:09 -07:00
Sunil Mushran
c834cdb157 ocfs2/dlm: Fix lockname in lockres print function
__dlm_print_one_lock_resource was printing lockname incorrectly.
Also, we now use printk directly instead of mlog as the latter prints
the line context which is not useful for this print.

Signed-off-by: Sunil Mushran <sunil.mushran@oracle.com>
Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-04-18 08:56:09 -07:00
Sunil Mushran
e5a0334cbd ocfs2/dlm: Move dlm_print_one_mle() from dlmmaster.c to dlmdebug.c
This patch helps in consolidating debugging related functions in dlmdebug.c.

Signed-off-by: Sunil Mushran <sunil.mushran@oracle.com>
Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-04-18 08:56:09 -07:00
Sunil Mushran
7209300a9b ocfs2/dlm: Dumps the purgelist into a debugfs file
This patch dumps all the lockres' on the purgelist it can fit in one page
into a debugfs file. Useful for debugging.

Signed-off-by: Sunil Mushran <sunil.mushran@oracle.com>
Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-04-18 08:56:09 -07:00
Sunil Mushran
d0129aceae ocfs2/dlm: Dumps the mles into a debugfs file
This patch dumps all mles it can fit in one page into a debugfs file.
Useful for debugging.

Signed-off-by: Sunil Mushran <sunil.mushran@oracle.com>
Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-04-18 08:56:09 -07:00
Sunil Mushran
751155a953 ocfs2/dlm: Move struct dlm_master_list_entry to dlmcommon.h
This patch moves some mle related definitions from dlmmaster.c
to dlmcommon.h. Future patches need these definitions to dump mle
debugging information.

Signed-off-by: Sunil Mushran <sunil.mushran@oracle.com>
Signed-off-by: Joel Becker <joel.beckeroracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-04-18 08:56:09 -07:00
Sunil Mushran
4e3d24ed1a ocfs2/dlm: Dumps the lockres' into a debugfs file
This patch dumps all the lockres' alongwith all the locks into
a debugfs file. Useful for debugging.

Signed-off-by: Sunil Mushran <sunil.mushran@oracle.com>
Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-04-18 08:56:09 -07:00
Sunil Mushran
007dce53a2 ocfs2/dlm: Dump the dlm state in a debugfs file
This patch dumps the dlm state (dlm_ctxt) into a debugfs file.
Useful for debugging.

Signed-off-by: Sunil Mushran <sunil.mushran@oracle.com>
Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-04-18 08:56:08 -07:00
Sunil Mushran
6325b4a22b ocfs2/dlm: Create debugfs dirs
This patch creates the debugfs directories that will hold the
files to be used to dump the dlm state.

Signed-off-by: Sunil Mushran <sunil.mushran@oracle.com>
Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-04-18 08:56:08 -07:00
Sunil Mushran
29576f8bb5 ocfs2/dlm: Link all lockres' to a tracking list
This patch links all the lockres' to a tracking list in dlm_ctxt.
We will use this in an upcoming patch that will walk the entire
list and to dump the lockres states to a debugfs file.

Signed-off-by: Sunil Mushran <sunil.mushran@oracle.com>
Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-04-18 08:56:08 -07:00
Sunil Mushran
724bdca9b8 ocfs2/dlm: Create slabcaches for lock and lockres
This patch makes the o2dlm allocate memory for lockres, lockname and lock
structures from slabcaches rather than kmalloc. This allows us to not only
make these allocs more efficient but also allows us to track the memory being
consumed by these structures.

Signed-off-by: Sunil Mushran <sunil.mushran@oracle.com>
Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-04-18 08:56:08 -07:00
Sunil Mushran
12eb0035d6 ocfs2/dlm: Rename slabcache dlm_mle_cache to o2dlm_mle
This patch renames dlm_mle_slabcache to prevent namespace clashes with fs/dlm.

Signed-off-by: Sunil Mushran <sunil.mushran@oracle.com>
Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-04-18 08:56:08 -07:00
Joel Becker
53f67e3386 ocfs2: Document /sys/fs/ocfs2
Add ABI documentation for these files:

	/sys/fs/ocfs2/max_locking_protocol
	/sys/fs/ocfs2/loaded_cluster_plugins
	/sys/fs/ocfs2/active_cluster_plugin
	/sys/fs/ocfs2/cluster_stack

Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-04-18 08:56:07 -07:00
Joel Becker
9341d22942 ocfs2: Allow selection of cluster plug-ins.
ocfs2 now supports plug-ins for the classic O2CB stack as well as
userspace cluster stacks in conjunction with fs/dlm.  This allows zero,
one, or both of the plug-ins to be selected in Kconfig.  For local mounts
(non-clustered), neither plug-in is needed.  Both plugins can be loaded
at one time, the runtime will select the one needed for the cluster
systme in use.

Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-04-18 08:56:07 -07:00
Joel Becker
b92eccdd28 ocfs2: Add kbuild for ocfs2_stack_user.ko
Add ocfs2_stack_user.ko to the Makefile so that it builds.

Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-04-18 08:56:07 -07:00
Joel Becker
8f318311fa ocfs2: Change mlog_bug_on to BUG_ON in ocfs2_lockid.h
The masklog code is in the o2cb stack, but ocfs2_lockid.h now needs to
be included by the user stack.  The BUG() in ocfs2_lock_type_string()
does not need masklog support, so change it to a regular BUG_ON().

Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-04-18 08:56:07 -07:00
David Teigland
cf4d8d75d8 ocfs2: add fsdlm to stackglue
Add code to use fs/dlm.

[ Modified to be part of the stack_user module -- Joel ]

Signed-off-by: David Teigland <teigland@redhat.com>
Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-04-18 08:56:07 -07:00
Joel Becker
d4b95eef4d ocfs2: Add the 'set version' message to the ocfs2_control device.
The "SETV" message sets the filesystem locking protocol version as
negotiated by the client.  The client negotiates based on the maximum
version advertised in /sys/fs/ocfs2/max_locking_protocol.

Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-04-18 08:56:07 -07:00
Joel Becker
3cfd4ab6b6 ocfs2: Add the local node id to the handshake.
This is the second part of the ocfs2_control handshake.  After
negotiating the ocfs2_control protocol, the daemon tells the filesystem
what the local node id is via the SETN message.

Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-04-18 08:56:06 -07:00
Joel Becker
de870ef022 ocfs2: Introduce the DOWN message to ocfs2_control
When the control daemon sees a node go down, it sends a DOWN message
through the ocfs2_control device.

Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-04-18 08:56:06 -07:00
Joel Becker
462c7e6a25 ocfs2: Start the ocfs2_control handshake.
When a control daemon opens the ocfs2_control device, it must perform a
handshake to tell the filesystem it is something capable of monitoring
cluster status.  Only after the handshake is complete will the filesystem
allow mounts.

This is the first part of the handshake.  The daemon reads all supported
ocfs2_control protocols, then writes in the protocol it will use.

Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-04-18 08:56:06 -07:00
Joel Becker
6427a72755 ocfs2: Add the ocfs2_control misc device.
The ocfs2_control misc device is how a userspace control daemon (controld)
talks to the filesystem.  Introduce the bare-bones filesystem ops.

Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-04-18 08:56:06 -07:00
Joel Becker
8adf0536c9 ocfs2: Add the user stack module.
Add a skeleton for the stack_user module.  It's just the barebones module
code.

Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-04-18 08:56:06 -07:00
Joel Becker
9c6c877c04 ocfs2: Add the 'cluster_stack' sysfs file.
Userspace can now query and specify the cluster stack in use via the
/sys/fs/ocfs2/cluster_stack file.  By default, it is 'o2cb', which is
the classic stack.  Thus, old tools that do not know how to modify this
file will work just fine.  The stack cannot be modified if there is a
live filesystem.

ocfs2_cluster_connect() now takes the expected cluster stack as an
argument.  This way, the filesystem and the stack glue ensure they are
speaking to the same backend.

If the stack is 'o2cb', the o2cb stack plugin is used.  For any other
value, the fsdlm stack plugin is selected.

Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-04-18 08:56:05 -07:00
Joel Becker
b61817e116 ocfs2: Add the USERSPACE_STACK incompat bit.
The filesystem gains the USERSPACE_STACK incomat bit and the
s_cluster_info field on the superblock.  When a userspace stack is in
use, the name of the stack is stored on-disk for mount-time
verification.

The "cluster_stack" option is added to mount(2) processing.  The mount
process needs to pass the matching stack name.  If the passed name and
the on-disk name do not match, the mount is failed.

When using the classic o2cb stack, the incompat bit is *not* set and no
mount option is used other than the usual heartbeat=local.  Thus, the
filesystem is compatible with older tools.

Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-04-18 08:56:05 -07:00
Joel Becker
74ae4e104d ocfs2: Create stack glue sysfs files.
Introduce a set of sysfs files that describe the current stack glue
state.  The files live under /sys/fs/ocfs2.  The locking_protocol file
displays the version of ocfs2's locking code.  The
loaded_cluster_plugins file displays all of the currently loaded stack
plugins.  When filesystems are mounted, the active_cluster_plugin file
will display the plugin in use.

Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-04-18 08:56:05 -07:00
Joel Becker
286eaa95c5 ocfs2: Break out stackglue into modules.
We define the ocfs2_stack_plugin structure to represent a stack driver.
The o2cb stack code is split into stack_o2cb.c.  This becomes the
ocfs2_stack_o2cb.ko module.

The stackglue generic functions are similarly split into the
ocfs2_stackglue.ko module.  This module now provides an interface to
register drivers.  The ocfs2_stack_o2cb driver registers itself.  As
part of this interface, ocfs2_stackglue can load drivers on demand.
This is accomplished in ocfs2_cluster_connect().

ocfs2_cluster_disconnect() is now notified when a _hangup() is pending.
If a hangup is pending, it will not release the driver module and will
let _hangup() do that.

Signed-off-by: Joel Becker <joel.becker@oracle.com>
2008-04-18 08:56:05 -07:00
Joel Becker
e3dad42bf9 ocfs2: Create ocfs2_stack_operations and split out the o2cb stack.
Define the ocfs2_stack_operations structure.  Build o2cb_stack_ops from
all of the o2cb-specific stack functions.  Change the generic stack glue
functions to call the stack_ops instead of the o2cb functions directly.

The o2cb functions are moved to stack_o2cb.c.  The headers are cleaned up
to where only needed headers are included.

In this code, stackglue.c and stack_o2cb.c refer to some shared
extern variables.  When they become modules, that will change.

Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-04-18 08:56:05 -07:00
Joel Becker
553aa7e408 ocfs2: Split o2cb code from generic stack functions.
Split off the o2cb-specific funtionality from the generic stack glue
calls.  This is a precurser to wrapping the o2cb functionality in an
operations vector.

Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-04-18 08:56:05 -07:00
Joel Becker
63e0c48ae6 ocfs2: Clean up stackglue initialization
The stack glue initialization function needs a better name so that it can be
used cleanly when stackglue becomes a module.

Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-04-18 08:56:05 -07:00
Joel Becker
cf0acdcd64 ocfs2: Abstract out a debugging function for underlying dlms.
dlmglue.c was still referencing a raw o2dlm lksb in one instance.  Let's
create a generic ocfs2_dlm_dump_lksb() function.  This allows underlying
DLMs to print whatever they want about their lock.

We then move the o2dlm dump into stackglue.c where it belongs.

Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-04-18 08:56:04 -07:00
David Teigland
1693a5c011 ocfs2: handle async EAGAIN from NOQUEUE request
When using fsdlm, -EAGAIN is returned in the async callback for NOQUEUE
requests. Fix up dlmglue to expect this.

Signed-off-by: David Teigland <teigland@redhat.com>
Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-04-18 08:56:04 -07:00
Joel Becker
de551246e7 ocfs2: Remove CANCELGRANT from the view of dlmglue.
o2dlm has the non-standard behavior of providing a cancel callback
(unlock_ast) even when the cancel has failed (the locking operation
succeeded without canceling).  This is called CANCELGRANT after the
status code sent to the callback.  fs/dlm does not provide this
callback, so dlmglue must be changed to live without it.
o2dlm_unlock_ast_wrapper() in stackglue now ignores CANCELGRANT calls.

Because dlmglue no longer sees CANCELGRANT, ocfs2_unlock_ast() no longer
needs to check for it.  ocfs2_locking_ast() must catch that a cancel was
tried and clear the cancel state.

Making these changes opens up a locking race.  dlmglue uses the the
OCFS2_LOCK_BUSY flag to ensure only one thread is calling the dlm at any
one time.  But dlmglue must unlock the lockres before calling into the
dlm.  In the small window of time between unlocking the lockres and
calling the dlm, the downconvert thread can try to cancel the lock.  The
downconvert thread is checking the OCFS2_LOCK_BUSY flag - it doesn't
know that ocfs2_dlm_lock() has not yet been called.

Because ocfs2_dlm_lock() has not yet been called, the cancel operation
will just be a no-op.  There's nothing to cancel.  With CANCELGRANT,
dlmglue uses the CANCELGRANT callback to clear up the cancel state.
When it comes around again, it will retry the cancel.  Eventually, the
first thread will have called into ocfs2_dlm_lock(), and either the
lock or the cancel will succeed.  The downconvert thread can then do its
downconvert.

Without CANCELGRANT, there is nothing to clean up the cancellation
state.  The downconvert thread does not know to retry its operations.
More importantly, the original lock may be blocking on the other node
that is trying to cancel us.  With neither able to make progress, the
ast is never called and the cancellation state is never cleaned up that
way.  dlmglue is deadlocked.

The OCFS2_LOCK_PENDING flag is introduced to remedy this window.  It is
set at the same time OCFS2_LOCK_BUSY is.  Thus, the downconvert thread
can check whether the lock is cancelable.  If not, it just loops around
to try again.  Once ocfs2_dlm_lock() is called, the thread then clears
OCFS2_LOCK_PENDING and wakes the downconvert thread.  Now, if the
downconvert thread finds the lock BUSY, it can safely try to cancel it.
Whether the cancel works or not, the state will be properly set and the
lock processing can continue.

Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-04-18 08:56:04 -07:00
Mark Fasheh
0abd6d1803 ocfs2: Fill node number during cluster stack init
It doesn't make sense to query for a node number before connecting to the
cluster stack. This should be safe to do because node_num is only just
printed,
and we're actually only moving the setting of node num a small amount
further in the mount process.

[ Disconnect when node query fails -- Joel ]

Reviewed-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-04-18 08:56:04 -07:00
Joel Becker
6953b4c008 ocfs2: Move o2hb functionality into the stack glue.
The last bit of classic stack used directly in ocfs2 code is o2hb.
Specifically, the check for heartbeat during mount and the call to
ocfs2_hb_ctl during unmount.

We create an extra API, ocfs2_cluster_hangup(), to encapsulate the call
to ocfs2_hb_ctl.  Other stacks will just leave hangup() empty.

The check for heartbeat is moved into ocfs2_cluster_connect().  It will
be matched by a similar check for other stacks.

With this change, only stackglue.c includes cluster/ headers.

Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-04-18 08:56:04 -07:00
Joel Becker
19fdb624dc ocfs2: Abstract out node number queries.
ocfs2 asks the cluster stack for the local node's node number for two
reasons; to fill the slot map and to print it. While the slot map isn't
necessary for userspace cluster stacks, the printing is very nice for
debugging. Thus we add ocfs2_cluster_this_node() as a generic API to get
this value. It is anticipated that the slot map will not be used under a
userspace cluster stack, so validity checks of the node num only need to
exist in the slot map code. Otherwise, it just gets used and printed as an
opaque value.

[ Fixed up some "int" versus "unsigned int" issues and made osb->node_num
  truly opaque. --Mark ]

Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2008-04-18 08:56:04 -07:00