GFS2 has been calling functions like dlm_lock() even after the lockspace
that these functions operate on has been released with
dlm_release_lockspace().  It has always assumed that those functions
would return -EINVAL in that case, but that was never guaranteed, and it
certainly is no longer the case since commit 4db41bf4f04f ("dlm: remove
ls_local_handle from struct dlm_ls").

To fix that, add proper lockspace locking.

Fixes: 3e11e5304150 ("GFS2: ignore unlock failures after withdraw")
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Reviewed-by: Andrew Price <anprice@redhat.com>

Get rid of the GLF_INVALIDATE_IN_PROGRESS flag: it was originally used
to indicate to add_to_queue() that the ->go_sync() and ->go_invalid()
operations were in progress, but as we have established in commit "gfs2:
Fix LM_FLAG_TRY* logic in add_to_queue", add_to_queue() has no need to
know.

Commit d99724c3c36a describes a race in which GLF_INVALIDATE_IN_PROGRESS
is used to serialize two processes which are both in do_xmote() at the
same time.  That analysis is wrong: the serialization happens via the
GLF_LOCK flag, which ensures that at most one glock operation can be
active at any time.

Fixes: d99724c3c36a ("gfs2: Close timing window with GLF_INVALIDATE_IN_PROGRESS")
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Reviewed-by: Andrew Price <anprice@redhat.com>

This field was introduced in commit 601ef0d52e96 ("gfs2: Force withdraw
to replay journals and wait for it to finish") and never used.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Reviewed-by: Andrew Price <anprice@redhat.com>

Since commit 38552ff676f0 ("gfs2: Fix and clean up create / evict
interaction"), the GIF_FREE_VFS_INODE flag isn't used anymore.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Reviewed-by: Andrew Price <anprice@redhat.com>

Get rid of the GIF_ALLOC_FAILED flag; we can now be confident that the
additional consistency check isn't needed.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>

Currently, sdp->sd_aspace and the per-inode metadata address spaces use
sb->s_bdev->bd_mapping->host as their ->host; folios in those address
spaces will thus appear to be on bdev rather than on gfs2 filesystems.
This is a problem because gfs2 doesn't support cgroup writeback
(SB_I_CGROUPWB), but bdev does.

Fix that by using a "dummy" gfs2 inode as ->host in those address
spaces.  When coming from a folio, folio->mapping->host->i_sb will then
be a gfs2 super block and the SB_I_CGROUPWB flag will not be set in
sb->s_iflags.

Based on a previous version from Bob Peterson from several years ago.
Thanks to Tetsuo Handa, Jan Kara, and Rafael Aquini for helping figure
this out.

Fixes: aaa2cacf8184 ("writeback: add lockdep annotation to inode_to_wb()")
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>

In gfs2_glock_dq(), we must drop the glock spin lock before calling
->lm_cancel, but this means that in the meantime, the operation we are
trying to cancel could complete.  If the operation completes
unsuccessfully, another holder can end up at the head of the queue and
another ->lm_lock operation can get started.  In this case, we would end
up canceling that second operation by accident.

To prevent that, introduce a new GLF_CANCELING flag.  Set that flag in
gfs2_glock_dq() when trying to cancel an operation.  When seeing that
flag, finish_xmote() will then keep the GLF_LOCK flag set to prevent
other glock operations from taking place.  gfs2_glock_dq() then
completes the cancelation attempt by clearing GLF_LOCK and
GLF_CANCELING.

In addition, add a missing GLF_DEMOTE_IN_PROGRESS check in
gfs2_glock_dq() to make sure that we won't accidentally cancel a demote
request.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>

Having this flag attached to the iopen glock instead of the inode is
much simpler; it eliminates a protential weird race in gfs2_try_evict().

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>

Introduce a new GLF_PENDING_REPLY flag to indicate that a reply from DLM
is expected.  Include that flag in glock dumps to show more clearly
what's going on.  (When the GLF_PENDING_REPLY flag is set, the GLF_LOCK
flag will also be set but the GLF_LOCK flag alone isn't sufficient to
tell that we are waiting for a DLM reply.)

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>

The GIF_DEFERRED_DELETE flag indicates an action that gfs2_evict_inode()
should take, so rename the flag to GIF_DEFER_DELETE to clarify.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>