Commit 053640a7 authored by Bob Peterson's avatar Bob Peterson Committed by Andreas Gruenbacher
Browse files

gfs2: Dequeue waiters when withdrawn 



When a withdraw occurs, ordinary (not system) glocks may not be granted
anymore. Later, when the file system is unmounted, gfs2_gl_hash_clear()
tries to clear out all the glocks, but these un-grantable pending
waiters prevent some glocks from being freed. So the unmount hangs, at
least for its ten-minute timeout period.

This patch takes measures to remove any pending waiters from
the glocks that will never be granted. This allows the unmount to
proceed in a reasonable period of time.

Signed-off-by: default avatarBob Peterson <rpeterso@redhat.com>
Signed-off-by: default avatarAndreas Gruenbacher <agruenba@redhat.com>
parent 04133b60

fs/gfs2/glock.c

+14 −0
Original line number Diff line number Diff line
@@ -2196,6 +2196,20 @@ static void dump_glock_func(struct gfs2_glock *gl) 
	dump_glock(NULL, gl, true);

}



static void withdraw_dq(struct gfs2_glock *gl)

{

	spin_lock(&gl->gl_lockref.lock);

	if (!__lockref_is_dead(&gl->gl_lockref) &&

	    glock_blocked_by_withdraw(gl))

		do_error(gl, LM_OUT_ERROR); /* remove pending waiters */

	spin_unlock(&gl->gl_lockref.lock);

}



void gfs2_gl_dq_holders(struct gfs2_sbd *sdp)

{

	glock_hash_walk(withdraw_dq, sdp);

}



/**

 * gfs2_gl_hash_clear - Empty out the glock hash table

 * @sdp: the filesystem

fs/gfs2/glock.h

+1 −0
Original line number Diff line number Diff line
@@ -274,6 +274,7 @@ extern void gfs2_cancel_delete_work(struct gfs2_glock *gl); 
extern bool gfs2_delete_work_queued(const struct gfs2_glock *gl);

extern void gfs2_flush_delete_work(struct gfs2_sbd *sdp);

extern void gfs2_gl_hash_clear(struct gfs2_sbd *sdp);

extern void gfs2_gl_dq_holders(struct gfs2_sbd *sdp);

extern void gfs2_glock_thaw(struct gfs2_sbd *sdp);

extern void gfs2_glock_add_to_lru(struct gfs2_glock *gl);

extern void gfs2_glock_free(struct gfs2_glock *gl);

fs/gfs2/util.c

+5 −0
Original line number Diff line number Diff line
@@ -164,6 +164,11 @@ static void signal_our_withdraw(struct gfs2_sbd *sdp) 
		}

		if (!ret)

			gfs2_make_fs_ro(sdp);

		/*

		 * Dequeue any pending non-system glock holders that can no

		 * longer be granted because the file system is withdrawn.

		 */

		gfs2_gl_dq_holders(sdp);

		gfs2_freeze_unlock(&freeze_gh);

	}