When gdlm_ast() is called with a non-zero status code, this means that
the requested operation did not succeed and the current lock state
didn't change.  Turn that into a non-zero LM_OUT_* status code (with ret
& ~LM_OUT_ST_MASK != 0) instead of pretending that dlm returned the
current lock state.

That way, we can easily change finish_xmote() to only update
gl->gl_state when the state has actually changed.

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

Currently, gfs2 always sets the DLM_LKF_VALBLK flag to enable lvb
handling even when sb_lvbptr is NULL.  This currently causes no problems
because DLM ignores the DLM_LKF_VALBLK flag when sb_lvbptr is NULL, but
it does violate the DLM API.  Fix that by only setting DLM_LKF_VALBLK
when sb_lvbptr is not NULL.

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

This patch moves the msleep_interruptible() out of the non-sleepable
context by moving the ls->ls_recover_spin spinlock around so
msleep_interruptible() will be called in a sleepable context.

Cc: stable@vger.kernel.org
Fixes: 4a7727725dc7 ("GFS2: Fix recovery issues for spectators")
Suggested-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>

The DLM_LKF_QUECVT flag needs to be set for "upward" lock conversions to
ensure fairness, but setting it for "downward" lock conversions will
lead to a failure.  The flag is currently set based on the GLF_BLOCKING
flag and it's not immediately obvious why this is correct.  Simplify
things by figuring out if a lock conversion is "upward" by looking at
the before and after locking modes instead of relying on the
GLF_BLOCKING flag.

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

Invert the meaning of the GLF_INITIAL flag: right now, when GLF_INITIAL
is set, a DLM lock exists and we have a valid identifier for it; when
GLF_INITIAL is cleared, no DLM lock exists (yet).  This is confusing.
In addition, it makes more sense to highlight the exceptional case
(i.e., no DLM lock exists yet) in glock dumps and trace points than to
highlight the common case.

To avoid confusion between the "old" and the "new" meaning of the flag,
use 'a' instead of 'I' to represent the flag.

For improved code consistency, check if the GLF_INITIAL flag is cleared
to determine whether a DLM lock exists instead of checking if the lock
identifier is non-zero.

Document what the flag is used for.

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

Rename the GLF_FREEING flag to GLF_UNLOCKED, and the ->go_free glock
operation to ->go_unlocked.  This mechanism is used to wait for the
underlying DLM lock to be unlocked; being able to free the glock is a
consequence of the DLM lock being unlocked.

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

At unmount time, we would generally like to explicitly unlock as few
glocks as possible for efficiency.  We are already skipping glocks that
don't have a lock value block (LVB), but we can also skip glocks which
are not held in DLM_LOCK_EX or DLM_LOCK_PW mode (of which gfs2 only uses
DLM_LOCK_EX under the name LM_ST_EXCLUSIVE).

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Cc: David Teigland <teigland@redhat.com>

When a DLM lockspace is released and there ares still locks in that
lockspace, DLM will unlock those locks automatically.  Commit
fb6791d100d1b started exploiting this behavior to speed up filesystem
unmount: gfs2 would simply free glocks it didn't want to unlock and then
release the lockspace.  This didn't take the bast callbacks for
asynchronous lock contention notifications into account, which remain
active until until a lock is unlocked or its lockspace is released.

To prevent those callbacks from accessing deallocated objects, put the
glocks that should not be unlocked on the sd_dead_glocks list, release
the lockspace, and only then free those glocks.

As an additional measure, ignore unexpected ast and bast callbacks if
the receiving glock is dead.

Fixes: fb6791d100d1b ("GFS2: skip dlm_unlock calls in unmount")
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Cc: David Teigland <teigland@redhat.com>

This function checks whether the filesystem has been been marked to be
withdrawn eventually or has been withdrawn already.  Rename this
function to avoid confusing code like checking for gfs2_withdrawing()
when gfs2_withdrawn() has already returned true.

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

The last user of this flag was removed in commit b77b4a4815a9 ("gfs2:
Rework freeze / thaw logic").

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