xfs: pass xfs_buf lookup flags to xfs_*read_agi

Allow callers to pass buffer lookup flags to xfs_read_agi and
xfs_ialloc_read_agi.  This will be used in the next patch to fix a
deadlock in the online fsck inode scanner.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

fs/xfs/libxfs/xfs_ag.c

@@ -194,7 +194,7 @@ xfs_initialize_perag_data(
 		pag = xfs_perag_get(mp, index);
 		error = xfs_alloc_read_agf(pag, NULL, 0, NULL);
 		if (!error)
-			error = xfs_ialloc_read_agi(pag, NULL, NULL);
+			error = xfs_ialloc_read_agi(pag, NULL, 0, NULL);
 		if (error) {
 			xfs_perag_put(pag);
 			return error;
@@ -931,7 +931,7 @@ xfs_ag_shrink_space(
 	int			error, err2;
 
 	ASSERT(pag->pag_agno == mp->m_sb.sb_agcount - 1);
-	error = xfs_ialloc_read_agi(pag, *tpp, &agibp);
+	error = xfs_ialloc_read_agi(pag, *tpp, 0, &agibp);
 	if (error)
 		return error;
 
@@ -1062,7 +1062,7 @@ xfs_ag_extend_space(
 
 	ASSERT(pag->pag_agno == pag->pag_mount->m_sb.sb_agcount - 1);
 
-	error = xfs_ialloc_read_agi(pag, tp, &bp);
+	error = xfs_ialloc_read_agi(pag, tp, 0, &bp);
 	if (error)
 		return error;
 
@@ -1119,7 +1119,7 @@ xfs_ag_get_geometry(
 	int			error;
 
 	/* Lock the AG headers. */
-	error = xfs_ialloc_read_agi(pag, NULL, &agi_bp);
+	error = xfs_ialloc_read_agi(pag, NULL, 0, &agi_bp);
 	if (error)
 		return error;
 	error = xfs_alloc_read_agf(pag, NULL, 0, &agf_bp);

fs/xfs/libxfs/xfs_ialloc.c

@@ -1699,7 +1699,7 @@ xfs_dialloc_good_ag(
 		return false;
 
 	if (!xfs_perag_initialised_agi(pag)) {
-		error = xfs_ialloc_read_agi(pag, tp, NULL);
+		error = xfs_ialloc_read_agi(pag, tp, 0, NULL);
 		if (error)
 			return false;
 	}
@@ -1768,7 +1768,7 @@ xfs_dialloc_try_ag(
 	 * Then read in the AGI buffer and recheck with the AGI buffer
 	 * lock held.
 	 */
-	error = xfs_ialloc_read_agi(pag, *tpp, &agbp);
+	error = xfs_ialloc_read_agi(pag, *tpp, 0, &agbp);
 	if (error)
 		return error;
 
@@ -2286,7 +2286,7 @@ xfs_difree(
 	/*
 	 * Get the allocation group header.
 	 */
-	error = xfs_ialloc_read_agi(pag, tp, &agbp);
+	error = xfs_ialloc_read_agi(pag, tp, 0, &agbp);
 	if (error) {
 		xfs_warn(mp, "%s: xfs_ialloc_read_agi() returned error %d.",
 			__func__, error);
@@ -2332,7 +2332,7 @@ xfs_imap_lookup(
 	int			error;
 	int			i;
 
-	error = xfs_ialloc_read_agi(pag, tp, &agbp);
+	error = xfs_ialloc_read_agi(pag, tp, 0, &agbp);
 	if (error) {
 		xfs_alert(mp,
 			"%s: xfs_ialloc_read_agi() returned error %d, agno %d",
@@ -2675,6 +2675,7 @@ int
 xfs_read_agi(
 	struct xfs_perag	*pag,
 	struct xfs_trans	*tp,
+	xfs_buf_flags_t		flags,
 	struct xfs_buf		**agibpp)
 {
 	struct xfs_mount	*mp = pag->pag_mount;
@@ -2684,7 +2685,7 @@ xfs_read_agi(
 
 	error = xfs_trans_read_buf(mp, tp, mp->m_ddev_targp,
 			XFS_AG_DADDR(mp, pag->pag_agno, XFS_AGI_DADDR(mp)),
-			XFS_FSS_TO_BB(mp, 1), 0, agibpp, &xfs_agi_buf_ops);
+			XFS_FSS_TO_BB(mp, 1), flags, agibpp, &xfs_agi_buf_ops);
 	if (xfs_metadata_is_sick(error))
 		xfs_ag_mark_sick(pag, XFS_SICK_AG_AGI);
 	if (error)
@@ -2704,6 +2705,7 @@ int
 xfs_ialloc_read_agi(
 	struct xfs_perag	*pag,
 	struct xfs_trans	*tp,
+	int			flags,
 	struct xfs_buf		**agibpp)
 {
 	struct xfs_buf		*agibp;
@@ -2712,7 +2714,9 @@ xfs_ialloc_read_agi(
 
 	trace_xfs_ialloc_read_agi(pag->pag_mount, pag->pag_agno);
 
-	error = xfs_read_agi(pag, tp, &agibp);
+	error = xfs_read_agi(pag, tp,
+			(flags & XFS_IALLOC_FLAG_TRYLOCK) ? XBF_TRYLOCK : 0,
+			&agibp);
 	if (error)
 		return error;
 

fs/xfs/libxfs/xfs_ialloc.h

@@ -63,10 +63,11 @@ xfs_ialloc_log_agi(
 	struct xfs_buf	*bp,		/* allocation group header buffer */
 	uint32_t	fields);	/* bitmask of fields to log */
 
-int xfs_read_agi(struct xfs_perag *pag, struct xfs_trans *tp,
+int xfs_read_agi(struct xfs_perag *pag, struct xfs_trans *tp, xfs_buf_flags_t flags,
 		struct xfs_buf **agibpp);
 int xfs_ialloc_read_agi(struct xfs_perag *pag, struct xfs_trans *tp,
-		struct xfs_buf **agibpp);
+		int flags, struct xfs_buf **agibpp);
+#define	XFS_IALLOC_FLAG_TRYLOCK	(1U << 0)  /* use trylock for buffer locking */
 
 /*
  * Lookup a record by ino in the btree given by cur.

fs/xfs/libxfs/xfs_ialloc_btree.c

@@ -745,7 +745,7 @@ xfs_finobt_count_blocks(
 	struct xfs_btree_cur	*cur;
 	int			error;
 
-	error = xfs_ialloc_read_agi(pag, tp, &agbp);
+	error = xfs_ialloc_read_agi(pag, tp, 0, &agbp);
 	if (error)
 		return error;
 
@@ -768,7 +768,7 @@ xfs_finobt_read_blocks(
 	struct xfs_agi		*agi;
 	int			error;
 
-	error = xfs_ialloc_read_agi(pag, tp, &agbp);
+	error = xfs_ialloc_read_agi(pag, tp, 0, &agbp);
 	if (error)
 		return error;
 

fs/xfs/scrub/common.c

@@ -445,7 +445,7 @@ xchk_perag_read_headers(
 {
 	int			error;
 
-	error = xfs_ialloc_read_agi(sa->pag, sc->tp, &sa->agi_bp);
+	error = xfs_ialloc_read_agi(sa->pag, sc->tp, 0, &sa->agi_bp);
 	if (error && want_ag_read_header_failure(sc, XFS_SCRUB_TYPE_AGI))
 		return error;
 
@@ -827,7 +827,7 @@ xchk_iget_agi(
 	 * in the iget cache miss path.
 	 */
 	pag = xfs_perag_get(mp, XFS_INO_TO_AGNO(mp, inum));
-	error = xfs_ialloc_read_agi(pag, tp, agi_bpp);
+	error = xfs_ialloc_read_agi(pag, tp, 0, agi_bpp);
 	xfs_perag_put(pag);
 	if (error)
 		return error;

fs/xfs/scrub/fscounters.c

@@ -85,7 +85,7 @@ xchk_fscount_warmup(
 			continue;
 
 		/* Lock both AG headers. */
-		error = xfs_ialloc_read_agi(pag, sc->tp, &agi_bp);
+		error = xfs_ialloc_read_agi(pag, sc->tp, 0, &agi_bp);
 		if (error)
 			break;
 		error = xfs_alloc_read_agf(pag, sc->tp, 0, &agf_bp);

fs/xfs/scrub/iscan.c

@@ -281,7 +281,7 @@ xchk_iscan_advance(
 		if (!pag)
 			return -ECANCELED;
 
-		ret = xfs_ialloc_read_agi(pag, sc->tp, &agi_bp);
+		ret = xfs_ialloc_read_agi(pag, sc->tp, 0, &agi_bp);
 		if (ret)
 			goto out_pag;
 

fs/xfs/scrub/repair.c

@@ -290,7 +290,7 @@ xrep_calc_ag_resblks(
 		icount = pag->pagi_count;
 	} else {
 		/* Try to get the actual counters from disk. */
-		error = xfs_ialloc_read_agi(pag, NULL, &bp);
+		error = xfs_ialloc_read_agi(pag, NULL, 0, &bp);
 		if (!error) {
 			icount = pag->pagi_count;
 			xfs_buf_relse(bp);
@@ -908,7 +908,7 @@ xrep_reinit_pagi(
 	ASSERT(xfs_perag_initialised_agi(pag));
 
 	clear_bit(XFS_AGSTATE_AGI_INIT, &pag->pag_opstate);
-	error = xfs_ialloc_read_agi(pag, sc->tp, &bp);
+	error = xfs_ialloc_read_agi(pag, sc->tp, 0, &bp);
 	if (error)
 		return error;
 
@@ -934,7 +934,7 @@ xrep_ag_init(
 
 	ASSERT(!sa->pag);
 
-	error = xfs_ialloc_read_agi(pag, sc->tp, &sa->agi_bp);
+	error = xfs_ialloc_read_agi(pag, sc->tp, 0, &sa->agi_bp);
 	if (error)
 		return error;
 

fs/xfs/xfs_inode.c

@@ -2167,7 +2167,7 @@ xfs_iunlink(
 	pag = xfs_perag_get(mp, XFS_INO_TO_AGNO(mp, ip->i_ino));
 
 	/* Get the agi buffer first.  It ensures lock ordering on the list. */
-	error = xfs_read_agi(pag, tp, &agibp);
+	error = xfs_read_agi(pag, tp, 0, &agibp);
 	if (error)
 		goto out;
 
@@ -2264,7 +2264,7 @@ xfs_iunlink_remove(
 	trace_xfs_iunlink_remove(ip);
 
 	/* Get the agi buffer first.  It ensures lock ordering on the list. */
-	error = xfs_read_agi(pag, tp, &agibp);
+	error = xfs_read_agi(pag, tp, 0, &agibp);
 	if (error)
 		return error;
 
@@ -3142,7 +3142,7 @@ xfs_rename(
 
 			pag = xfs_perag_get(mp,
 					XFS_INO_TO_AGNO(mp, inodes[i]->i_ino));
-			error = xfs_read_agi(pag, tp, &bp);
+			error = xfs_read_agi(pag, tp, 0, &bp);
 			xfs_perag_put(pag);
 			if (error)
 				goto out_trans_cancel;
@@ -3814,7 +3814,7 @@ xfs_inode_reload_unlinked_bucket(
 
 	/* Grab the first inode in the list */
 	pag = xfs_perag_get(mp, agno);
-	error = xfs_ialloc_read_agi(pag, tp, &agibp);
+	error = xfs_ialloc_read_agi(pag, tp, 0, &agibp);
 	xfs_perag_put(pag);
 	if (error)
 		return error;

fs/xfs/xfs_iwalk.c

@@ -268,7 +268,7 @@ xfs_iwalk_ag_start(
 
 	/* Set up a fresh cursor and empty the inobt cache. */
 	iwag->nr_recs = 0;
-	error = xfs_ialloc_read_agi(pag, tp, agi_bpp);
+	error = xfs_ialloc_read_agi(pag, tp, 0, agi_bpp);
 	if (error)
 		return error;
 	*curpp = xfs_inobt_init_cursor(pag, tp, *agi_bpp);
@@ -386,7 +386,7 @@ xfs_iwalk_run_callbacks(
 	}
 
 	/* ...and recreate the cursor just past where we left off. */
-	error = xfs_ialloc_read_agi(iwag->pag, iwag->tp, agi_bpp);
+	error = xfs_ialloc_read_agi(iwag->pag, iwag->tp, 0, agi_bpp);
 	if (error)
 		return error;
 	*curpp = xfs_inobt_init_cursor(iwag->pag, iwag->tp, *agi_bpp);

fs/xfs/xfs_log_recover.c

@@ -2656,7 +2656,7 @@ xlog_recover_clear_agi_bucket(
 	if (error)
 		goto out_error;
 
-	error = xfs_read_agi(pag, tp, &agibp);
+	error = xfs_read_agi(pag, tp, 0, &agibp);
 	if (error)
 		goto out_abort;
 
@@ -2772,7 +2772,7 @@ xlog_recover_iunlink_ag(
 	int			bucket;
 	int			error;
 
-	error = xfs_read_agi(pag, NULL, &agibp);
+	error = xfs_read_agi(pag, NULL, 0, &agibp);
 	if (error) {
 		/*
 		 * AGI is b0rked. Don't process it.