[Cluster-devel] [GFS2 PATCH 15/28] gfs2: fix infinite loop when checking ail item count before go_inval
Bob Peterson
rpeterso at redhat.com
Thu Feb 20 19:53:16 UTC 2020
Before this patch, the rgrp_go_inval and inode_go_inval functions each
checked if there were any items left on the ail count (by way of a
count), and if so, did a withdraw. But the withdraw code now uses
glocks when changing the file system to read-only status. So we can
not have glock functions withdrawing or a hang will likely result:
The glocks can't be serviced by the work_func if the work_func is
busy doing its own withdraw.
This patch removes the checks from the go_inval functions and adds
a centralized check in do_xmote to warn about the problem and not
withdraw, but flag the error so it's eventually caught when the logd
daemon eventually runs.
Signed-off-by: Bob Peterson <rpeterso at redhat.com>
Reviewed-by: Andreas Gruenbacher <agruenba at redhat.com>
---
fs/gfs2/glock.c | 17 +++++++++++++++--
fs/gfs2/glops.c | 3 ---
2 files changed, 15 insertions(+), 5 deletions(-)
diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c
index 7602d0e2492c..5afaf92057c0 100644
--- a/fs/gfs2/glock.c
+++ b/fs/gfs2/glock.c
@@ -604,9 +604,22 @@ __acquires(&gl->gl_lockref.lock)
spin_unlock(&gl->gl_lockref.lock);
if (glops->go_sync)
glops->go_sync(gl);
- if (test_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags))
+ if (test_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags)) {
+ /*
+ * The call to go_sync should have cleared out the ail list.
+ * If there are still items, we have a problem. We ought to
+ * withdraw, but we can't because the withdraw code also uses
+ * glocks. Warn about the error, dump the glock, then fall
+ * through and wait for logd to do the withdraw for us.
+ */
+ if ((atomic_read(&gl->gl_ail_count) != 0) &&
+ (!cmpxchg(&sdp->sd_log_error, 0, -EIO))) {
+ gfs2_assert_warn(sdp, !atomic_read(&gl->gl_ail_count));
+ gfs2_dump_glock(NULL, gl, true);
+ }
glops->go_inval(gl, target == LM_ST_DEFERRED ? 0 : DIO_METADATA);
- clear_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags);
+ clear_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags);
+ }
gfs2_glock_hold(gl);
if (sdp->sd_lockstruct.ls_ops->lm_lock) {
diff --git a/fs/gfs2/glops.c b/fs/gfs2/glops.c
index 7cfacbe35e59..b58924482d9a 100644
--- a/fs/gfs2/glops.c
+++ b/fs/gfs2/glops.c
@@ -188,7 +188,6 @@ static void rgrp_go_inval(struct gfs2_glock *gl, int flags)
gfs2_rgrp_brelse(rgd);
WARN_ON_ONCE(!(flags & DIO_METADATA));
- gfs2_assert_withdraw(sdp, !atomic_read(&gl->gl_ail_count));
truncate_inode_pages_range(mapping, gl->gl_vm.start, gl->gl_vm.end);
if (rgd)
@@ -288,8 +287,6 @@ static void inode_go_inval(struct gfs2_glock *gl, int flags)
{
struct gfs2_inode *ip = gfs2_glock2inode(gl);
- gfs2_assert_withdraw(gl->gl_name.ln_sbd, !atomic_read(&gl->gl_ail_count));
-
if (flags & DIO_METADATA) {
struct address_space *mapping = gfs2_glock2aspace(gl);
truncate_inode_pages(mapping, 0);
--
2.24.1
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