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Commit cc0581bd authored by Bob Peterson's avatar Bob Peterson Committed by Steven Whitehouse
Browse files

GFS2: stuck in inode wait, no glocks stuck 



This patch changes the lock ordering when gfs2 reclaims
unlinked dinodes, thereby avoiding a livelock.

Signed-off-by: default avatarBob Peterson <rpeterso@redhat.com>
Signed-off-by: default avatarSteven Whitehouse <swhiteho@redhat.com>
parent eaefbf96

fs/gfs2/rgrp.c

+30 −48
Original line number Diff line number Diff line
@@ -952,16 +952,14 @@ static int try_rgrp_fit(struct gfs2_rgrpd *rgd, struct gfs2_alloc *al) 
 *          The inode, if one has been found, in inode.

 */



static int try_rgrp_unlink(struct gfs2_rgrpd *rgd, u64 *last_unlinked,

			   u64 skip, struct inode **inode)

static u64 try_rgrp_unlink(struct gfs2_rgrpd *rgd, u64 *last_unlinked,

			   u64 skip)

{

	u32 goal = 0, block;

	u64 no_addr;

	struct gfs2_sbd *sdp = rgd->rd_sbd;

	unsigned int n;

	int error = 0;



	*inode = NULL;

	for(;;) {

		if (goal >= rgd->rd_data)

			break;
@@ -981,10 +979,7 @@ static int try_rgrp_unlink(struct gfs2_rgrpd *rgd, u64 *last_unlinked, 
		if (no_addr == skip)

			continue;

		*last_unlinked = no_addr;

		error = gfs2_unlinked_inode_lookup(rgd->rd_sbd->sd_vfs,

						   no_addr, inode);

		if (*inode || error)

			return error;

		return no_addr;

	}



	rgd->rd_flags &= ~GFS2_RDF_CHECK;
@@ -1069,11 +1064,12 @@ static void forward_rgrp_set(struct gfs2_sbd *sdp, struct gfs2_rgrpd *rgd) 
 * Try to acquire rgrp in way which avoids contending with others.

 *

 * Returns: errno

 *          unlinked: the block address of an unlinked block to be reclaimed

 */



static struct inode *get_local_rgrp(struct gfs2_inode *ip, u64 *last_unlinked)

static int get_local_rgrp(struct gfs2_inode *ip, u64 *unlinked,

			  u64 *last_unlinked)

{

	struct inode *inode = NULL;

	struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);

	struct gfs2_rgrpd *rgd, *begin = NULL;

	struct gfs2_alloc *al = ip->i_alloc;
@@ -1082,6 +1078,7 @@ static struct inode *get_local_rgrp(struct gfs2_inode *ip, u64 *last_unlinked) 
	int loops = 0;

	int error, rg_locked;



	*unlinked = 0;

	rgd = gfs2_blk2rgrpd(sdp, ip->i_goal);



	while (rgd) {
@@ -1103,29 +1100,19 @@ static struct inode *get_local_rgrp(struct gfs2_inode *ip, u64 *last_unlinked) 
			   because that would require an iput which can only

			   happen after the rgrp is unlocked. */

			if (!rg_locked && rgd->rd_flags & GFS2_RDF_CHECK)

				error = try_rgrp_unlink(rgd, last_unlinked,

							ip->i_no_addr, &inode);

				*unlinked = try_rgrp_unlink(rgd, last_unlinked,

							   ip->i_no_addr);

			if (!rg_locked)

				gfs2_glock_dq_uninit(&al->al_rgd_gh);

			if (inode) {

				if (error) {

					if (inode->i_state & I_NEW)

						iget_failed(inode);

					else

						iput(inode);

					return ERR_PTR(error);

				}

				return inode;

			}

			if (error)

				return ERR_PTR(error);

			if (*unlinked)

				return -EAGAIN;

			/* fall through */

		case GLR_TRYFAILED:

			rgd = recent_rgrp_next(rgd);

			break;



		default:

			return ERR_PTR(error);

			return error;

		}

	}
@@ -1148,22 +1135,12 @@ static struct inode *get_local_rgrp(struct gfs2_inode *ip, u64 *last_unlinked) 
			if (try_rgrp_fit(rgd, al))

				goto out;

			if (!rg_locked && rgd->rd_flags & GFS2_RDF_CHECK)

				error = try_rgrp_unlink(rgd, last_unlinked,

							ip->i_no_addr, &inode);

				*unlinked = try_rgrp_unlink(rgd, last_unlinked,

							    ip->i_no_addr);

			if (!rg_locked)

				gfs2_glock_dq_uninit(&al->al_rgd_gh);

			if (inode) {

				if (error) {

					if (inode->i_state & I_NEW)

						iget_failed(inode);

					else

						iput(inode);

					return ERR_PTR(error);

				}

				return inode;

			}

			if (error)

				return ERR_PTR(error);

			if (*unlinked)

				return -EAGAIN;

			break;



		case GLR_TRYFAILED:
@@ -1171,7 +1148,7 @@ static struct inode *get_local_rgrp(struct gfs2_inode *ip, u64 *last_unlinked) 
			break;



		default:

			return ERR_PTR(error);

			return error;

		}



		rgd = gfs2_rgrpd_get_next(rgd);
@@ -1180,7 +1157,7 @@ static struct inode *get_local_rgrp(struct gfs2_inode *ip, u64 *last_unlinked) 


		if (rgd == begin) {

			if (++loops >= 3)

				return ERR_PTR(-ENOSPC);

				return -ENOSPC;

			if (!skipped)

				loops++;

			flags = 0;
@@ -1200,7 +1177,7 @@ out: 
		forward_rgrp_set(sdp, rgd);

	}



	return NULL;

	return 0;

}



/**
@@ -1216,7 +1193,7 @@ int gfs2_inplace_reserve_i(struct gfs2_inode *ip, char *file, unsigned int line) 
	struct gfs2_alloc *al = ip->i_alloc;

	struct inode *inode;

	int error = 0;

	u64 last_unlinked = NO_BLOCK;

	u64 last_unlinked = NO_BLOCK, unlinked;



	if (gfs2_assert_warn(sdp, al->al_requested))

		return -EINVAL;
@@ -1232,14 +1209,19 @@ try_again: 
	if (error)

		return error;



	inode = get_local_rgrp(ip, &last_unlinked);

	if (inode) {

	error = get_local_rgrp(ip, &unlinked, &last_unlinked);

	if (error) {

		if (ip != GFS2_I(sdp->sd_rindex))

			gfs2_glock_dq_uninit(&al->al_ri_gh);

		if (IS_ERR(inode))

			return PTR_ERR(inode);

		if (error != -EAGAIN)

			return error;

		error = gfs2_unlinked_inode_lookup(ip->i_inode.i_sb,

						   unlinked, &inode);

		if (inode)

			iput(inode);

		gfs2_log_flush(sdp, NULL);

		if (error == GLR_TRYFAILED)

			error = 0;

		goto try_again;

	}