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gfs2: Fix LM_FLAG_TRY* logic in add_to_queue

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The logic in add_to_queue() for determining whether a LM_FLAG_TRY or
LM_FLAG_TRY_1CB holder should be queued does not make any sense: we are
interested in wether or not the new operation will block behind an
existing or future holder in the queue, but the current code checks for
ongoing locking or ->go_inval() operations, which has little to do with
that.

Replace that code with something more sensible, remove the incorrect
add_to_queue() function annotations, remove the similarly misguided
do_error(gl, 0) call in do_xmote(), and add a missing comment to the
same call in do_promote().

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Reviewed-by: Andrew Price <anprice@redhat.com>
This commit is contained in:
Andreas Gruenbacher 2025-08-08 22:31:59 +02:00
parent 2b813a7288
commit 0c23e24164
1 changed files with 24 additions and 23 deletions
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47
fs/gfs2/glock.c
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@ -502,7 +502,7 @@ static bool do_promote(struct gfs2_glock *gl)
*/
if (list_is_first(&gh->gh_list, &gl->gl_holders))
return false;
do_error(gl, 0);
do_error(gl, 0); /* Fail queued try locks */
break;
}
set_bit(HIF_HOLDER, &gh->gh_iflags);
@ -713,7 +713,6 @@ __acquires(&gl->gl_lockref.lock)
if (test_and_set_bit(GLF_INVALIDATE_IN_PROGRESS,
&gl->gl_flags))
return;
do_error(gl, 0); /* Fail queued try locks */
}
if (!glops->go_inval && !glops->go_sync)
goto skip_inval;
@ -1459,6 +1458,24 @@ void gfs2_print_dbg(struct seq_file *seq, const char *fmt, ...)
va_end(args);
}
static bool gfs2_should_queue_trylock(struct gfs2_glock *gl,
struct gfs2_holder *gh)
{
struct gfs2_holder *current_gh, *gh2;
current_gh = find_first_holder(gl);
if (current_gh && !may_grant(gl, current_gh, gh))
return false;
list_for_each_entry(gh2, &gl->gl_holders, gh_list) {
if (test_bit(HIF_HOLDER, &gh2->gh_iflags))
continue;
if (!(gh2->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB)))
return false;
}
return true;
}
static inline bool pid_is_meaningful(const struct gfs2_holder *gh)
{
if (!(gh->gh_flags & GL_NOPID))
@ -1477,27 +1494,20 @@ static inline bool pid_is_meaningful(const struct gfs2_holder *gh)
*/
static inline void add_to_queue(struct gfs2_holder *gh)
__releases(&gl->gl_lockref.lock)
__acquires(&gl->gl_lockref.lock)
{
struct gfs2_glock *gl = gh->gh_gl;
struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
struct gfs2_holder *gh2;
int try_futile = 0;
GLOCK_BUG_ON(gl, gh->gh_owner_pid == NULL);
if (test_and_set_bit(HIF_WAIT, &gh->gh_iflags))
GLOCK_BUG_ON(gl, true);
if (gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB)) {
if (test_bit(GLF_LOCK, &gl->gl_flags)) {
struct gfs2_holder *current_gh;
current_gh = find_first_holder(gl);
try_futile = !may_grant(gl, current_gh, gh);
}
if (test_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags))
goto fail;
if ((gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB)) &&
!gfs2_should_queue_trylock(gl, gh)) {
gh->gh_error = GLR_TRYFAILED;
gfs2_holder_wake(gh);
return;
}
list_for_each_entry(gh2, &gl->gl_holders, gh_list) {
@ -1509,15 +1519,6 @@ __acquires(&gl->gl_lockref.lock)
continue;
goto trap_recursive;
}
list_for_each_entry(gh2, &gl->gl_holders, gh_list) {
if (try_futile &&
!(gh2->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB))) {
fail:
gh->gh_error = GLR_TRYFAILED;
gfs2_holder_wake(gh);
return;
}
}
trace_gfs2_glock_queue(gh, 1);
gfs2_glstats_inc(gl, GFS2_LKS_QCOUNT);
gfs2_sbstats_inc(gl, GFS2_LKS_QCOUNT);