Commit 33dbd1e4 authored by Bob Peterson's avatar Bob Peterson
Browse files

gfs2: fix infinite loop when checking ail item count before go_inval 



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: default avatarBob Peterson <rpeterso@redhat.com>
Reviewed-by: default avatarAndreas Gruenbacher <agruenba@redhat.com>
parent 601ef0d5

fs/gfs2/glock.c

+15 −2
Original line number Diff line number Diff line
@@ -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);

	}



	gfs2_glock_hold(gl);

	if (sdp->sd_lockstruct.ls_ops->lm_lock)	{

fs/gfs2/glops.c

+0 −3
Original line number Diff line number Diff line
@@ -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);

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