[GFS2] Fix log entry list corruption (68835625) · Commits · 戴 / test

When glock_lo_add and rg_lo_add attempt to add an element to the log, they check to see if has already been added before locking the log. If another process adds that element to the log in this window between the check and locking the log, the element will be added to the list twice. This causes the log element list to become corrupted in such a way that the log element can never be successfully removed from the list. This patch pulls the list_empty() check inside the log lock, to remove this window. Signed-off-by:

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

Steven Whitehouse <swhiteho@redhat.com>

fs/gfs2/lops.c

+11 −9

Original line number	Diff line number	Diff line
		@@ -33,16 +33,17 @@ static void glock_lo_add(struct gfs2_sbd sdp, struct gfs2_log_element le)

		tr->tr_touched = 1;

		if (!list_empty(&le->le_list))
		return;

		gl = container_of(le, struct gfs2_glock, gl_le);
		if (gfs2_assert_withdraw(sdp, gfs2_glock_is_held_excl(gl)))
		return;
		gfs2_glock_hold(gl);
		set_bit(GLF_DIRTY, &gl->gl_flags);

		gfs2_log_lock(sdp);
		if (!list_empty(&le->le_list)){
		gfs2_log_unlock(sdp);
		return;
		}
		gfs2_glock_hold(gl);
		set_bit(GLF_DIRTY, &gl->gl_flags);
		sdp->sd_log_num_gl++;
		list_add(&le->le_list, &sdp->sd_log_le_gl);
		gfs2_log_unlock(sdp);
		@@ -415,13 +416,14 @@ static void rg_lo_add(struct gfs2_sbd sdp, struct gfs2_log_element le)

		tr->tr_touched = 1;

		if (!list_empty(&le->le_list))
		return;

		rgd = container_of(le, struct gfs2_rgrpd, rd_le);
		gfs2_rgrp_bh_hold(rgd);

		gfs2_log_lock(sdp);
		if (!list_empty(&le->le_list)){
		gfs2_log_unlock(sdp);
		return;
		}
		gfs2_rgrp_bh_hold(rgd);
		sdp->sd_log_num_rg++;
		list_add(&le->le_list, &sdp->sd_log_le_rg);
		gfs2_log_unlock(sdp);

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