GFS2: Fix locking bug in failed shared to exclusive conversion (02ffad08) · Commits · 戴 / test

After calling out to the dlm, GFS2 sets the new state of a glock to gl_target in gdlm_ast(). However, gl_target is not always the lock state that was requested. If a conversion from shared to exclusive fails, finish_xmote() will call do_xmote() with LM_ST_UNLOCKED, instead of gl->gl_target, so that it can reacquire the lock in exlusive the next time around. In this case, setting the lock to gl_target in gdlm_ast() will make GFS2 think that it has the glock in exclusive mode, when really, it doesn't have the glock locked at all. This patch adds a new field to the gfs2_glock structure, gl_req, to track the mode that was requested. Signed-off-by:

Benjamin Marzinski <bmarzins@redhat.com> Signed-off-by:

Steven Whitehouse <swhiteho@redhat.com>

fs/gfs2/incore.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -203,6 +203,7 @@ struct gfs2_glock {
		unsigned int gl_target;
		unsigned int gl_reply;
		unsigned int gl_hash;
		unsigned int gl_req;
		unsigned int gl_demote_state; /* state requested by remote node */
		unsigned long gl_demote_time; /* time of first demote request */
		struct list_head gl_holders;

fs/gfs2/lock_dlm.c

+4 −3

Original line number	Diff line number	Diff line
		@@ -46,11 +46,11 @@ static void gdlm_ast(void *arg)
		BUG();
		}

		ret = gl->gl_target;
		ret = gl->gl_req;
		if (gl->gl_lksb.sb_flags & DLM_SBF_ALTMODE) {
		if (gl->gl_target == LM_ST_SHARED)
		if (gl->gl_req == LM_ST_SHARED)
		ret = LM_ST_DEFERRED;
		else if (gl->gl_target == LM_ST_DEFERRED)
		else if (gl->gl_req == LM_ST_DEFERRED)
		ret = LM_ST_SHARED;
		else
		BUG();
		@@ -147,6 +147,7 @@ static unsigned int gdlm_lock(struct gfs2_glock *gl,
		int req;
		u32 lkf;

		gl->gl_req = req_state;
		req = make_mode(req_state);
		lkf = make_flags(gl->gl_lksb.sb_lkid, flags, req);

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