Commit 5a61ae14 authored by Andreas Gruenbacher's avatar Andreas Gruenbacher
Browse files

gfs2: Make sure we don't miss any delayed withdraws 



Commit ca399c96 changes gfs2_log_flush to not withdraw the
filesystem while holding the log flush lock, but it fails to check if
the filesystem needs to be withdrawn once the log flush lock has been
released.  Likewise, commit f05b86db depends on gfs2_log_flush to
trigger for delayed withdraws.  Add that and clean up the code flow
somewhat.

In gfs2_put_super, add a check for delayed withdraws that have been
missed to prevent these kinds of bugs in the future.

Fixes: ca399c96 ("gfs2: flesh out delayed withdraw for gfs2_log_flush")
Fixes: f05b86db ("gfs2: Prepare to withdraw as soon as an IO error occurs in log write")
Cc: stable@vger.kernel.org # v5.7+: 462582b9: gfs2: add some much needed cleanup for log flushes that fail
Signed-off-by: default avatarAndreas Gruenbacher <agruenba@redhat.com>
parent bbf5c979

fs/gfs2/log.c

+31 −30
Original line number Diff line number Diff line
@@ -954,10 +954,8 @@ void gfs2_log_flush(struct gfs2_sbd *sdp, struct gfs2_glock *gl, u32 flags) 
		goto out;



	/* Log might have been flushed while we waited for the flush lock */

	if (gl && !test_bit(GLF_LFLUSH, &gl->gl_flags)) {

		up_write(&sdp->sd_log_flush_lock);

		return;

	}

	if (gl && !test_bit(GLF_LFLUSH, &gl->gl_flags))

		goto out;

	trace_gfs2_log_flush(sdp, 1, flags);



	if (flags & GFS2_LOG_HEAD_FLUSH_SHUTDOWN)
@@ -971,25 +969,25 @@ void gfs2_log_flush(struct gfs2_sbd *sdp, struct gfs2_glock *gl, u32 flags) 
		if (unlikely (state == SFS_FROZEN))

			if (gfs2_assert_withdraw_delayed(sdp,

			       !tr->tr_num_buf_new && !tr->tr_num_databuf_new))

				goto out;

				goto out_withdraw;

	}



	if (unlikely(state == SFS_FROZEN))

		if (gfs2_assert_withdraw_delayed(sdp, !sdp->sd_log_num_revoke))

			goto out;

			goto out_withdraw;

	if (gfs2_assert_withdraw_delayed(sdp,

			sdp->sd_log_num_revoke == sdp->sd_log_committed_revoke))

		goto out;

		goto out_withdraw;



	gfs2_ordered_write(sdp);

	if (gfs2_withdrawn(sdp))

		goto out;

		goto out_withdraw;

	lops_before_commit(sdp, tr);

	if (gfs2_withdrawn(sdp))

		goto out;

		goto out_withdraw;

	gfs2_log_submit_bio(&sdp->sd_log_bio, REQ_OP_WRITE);

	if (gfs2_withdrawn(sdp))

		goto out;

		goto out_withdraw;



	if (sdp->sd_log_head != sdp->sd_log_flush_head) {

		log_flush_wait(sdp);
@@ -1000,7 +998,7 @@ void gfs2_log_flush(struct gfs2_sbd *sdp, struct gfs2_glock *gl, u32 flags) 
		log_write_header(sdp, flags);

	}

	if (gfs2_withdrawn(sdp))

		goto out;

		goto out_withdraw;

	lops_after_commit(sdp, tr);



	gfs2_log_lock(sdp);
@@ -1020,7 +1018,7 @@ void gfs2_log_flush(struct gfs2_sbd *sdp, struct gfs2_glock *gl, u32 flags) 
		if (!sdp->sd_log_idle) {

			empty_ail1_list(sdp);

			if (gfs2_withdrawn(sdp))

				goto out;

				goto out_withdraw;

			atomic_dec(&sdp->sd_log_blks_free); /* Adjust for unreserved buffer */

			trace_gfs2_log_blocks(sdp, -1);

			log_write_header(sdp, flags);
@@ -1033,8 +1031,16 @@ void gfs2_log_flush(struct gfs2_sbd *sdp, struct gfs2_glock *gl, u32 flags) 
			atomic_set(&sdp->sd_freeze_state, SFS_FROZEN);

	}



out_end:

	trace_gfs2_log_flush(sdp, 0, flags);

out:

	if (gfs2_withdrawn(sdp)) {

	up_write(&sdp->sd_log_flush_lock);

	gfs2_trans_free(sdp, tr);

	if (gfs2_withdrawing(sdp))

		gfs2_withdraw(sdp);

	return;



out_withdraw:

	trans_drain(tr);

	/**

	 * If the tr_list is empty, we're withdrawing during a log
@@ -1048,12 +1054,7 @@ out: 
	spin_unlock(&sdp->sd_ail_lock);

	ail_drain(sdp); /* frees all transactions */

	tr = NULL;

	}



	trace_gfs2_log_flush(sdp, 0, flags);

	up_write(&sdp->sd_log_flush_lock);



	gfs2_trans_free(sdp, tr);

	goto out_end;

}



/**

fs/gfs2/super.c

+2 −0
Original line number Diff line number Diff line
@@ -702,6 +702,8 @@ restart: 
		if (error)

			gfs2_io_error(sdp);

	}

	WARN_ON(gfs2_withdrawing(sdp));



	/*  At this point, we're through modifying the disk  */



	/*  Release stuff  */

fs/gfs2/util.h

+10 −0
Original line number Diff line number Diff line
@@ -205,6 +205,16 @@ static inline bool gfs2_withdrawn(struct gfs2_sbd *sdp) 
		test_bit(SDF_WITHDRAWING, &sdp->sd_flags);

}



/**

 * gfs2_withdrawing - check if a withdraw is pending

 * @sdp: the superblock

 */

static inline bool gfs2_withdrawing(struct gfs2_sbd *sdp)

{

	return test_bit(SDF_WITHDRAWING, &sdp->sd_flags) &&

	       !test_bit(SDF_WITHDRAWN, &sdp->sd_flags);

}



#define gfs2_tune_get(sdp, field) \

gfs2_tune_get_i(&(sdp)->sd_tune, &(sdp)->sd_tune.field)

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