[PATCH] xfs: get rid of unnecessary xfs_perag_{get,put} pairs

[Gao Xiang <hsiangkao@redhat.com>]

Sometimes no need to play with perag_tree since for many
cases perag can also be accessed by agbp reliably.

Signed-off-by: Gao Xiang <hsiangkao@redhat.com>
---
Not sure addressing all the cases, but seems mostly.
Kindly correct me if something wrong somewhere...

 fs/xfs/libxfs/xfs_ag.c             |  4 ++--
 fs/xfs/libxfs/xfs_alloc.c          | 22 ++++++-----------
 fs/xfs/libxfs/xfs_alloc_btree.c    | 10 ++++----
 fs/xfs/libxfs/xfs_ialloc.c         | 28 ++++++----------------
 fs/xfs/libxfs/xfs_refcount_btree.c |  5 ++--
 fs/xfs/libxfs/xfs_rmap_btree.c     |  5 ++--
 fs/xfs/xfs_inode.c                 | 38 +++++++++---------------------
 7 files changed, 35 insertions(+), 77 deletions(-)

diff --git a/fs/xfs/libxfs/xfs_ag.c b/fs/xfs/libxfs/xfs_ag.c
index 9d84007a5c65..8cf73fe4338e 100644
--- a/fs/xfs/libxfs/xfs_ag.c
+++ b/fs/xfs/libxfs/xfs_ag.c
@@ -563,7 +563,8 @@ xfs_ag_get_geometry(
 	error = xfs_alloc_read_agf(mp, NULL, agno, 0, &agf_bp);
 	if (error)
 		goto out_agi;
-	pag = xfs_perag_get(mp, agno);
+
+	pag = agi_bp->b_pag;
 
 	/* Fill out form. */
 	memset(ageo, 0, sizeof(*ageo));
@@ -583,7 +584,6 @@ xfs_ag_get_geometry(
 	xfs_ag_geom_health(pag, ageo);
 
 	/* Release resources. */
-	xfs_perag_put(pag);
 	xfs_buf_relse(agf_bp);
 out_agi:
 	xfs_buf_relse(agi_bp);
diff --git a/fs/xfs/libxfs/xfs_alloc.c b/fs/xfs/libxfs/xfs_alloc.c
index 203e74fa64aa..bf4d07e5c73f 100644
--- a/fs/xfs/libxfs/xfs_alloc.c
+++ b/fs/xfs/libxfs/xfs_alloc.c
@@ -710,13 +710,12 @@ xfs_alloc_read_agfl(
 STATIC int
 xfs_alloc_update_counters(
 	struct xfs_trans	*tp,
-	struct xfs_perag	*pag,
 	struct xfs_buf		*agbp,
 	long			len)
 {
 	struct xfs_agf		*agf = agbp->b_addr;
 
-	pag->pagf_freeblks += len;
+	agbp->b_pag->pagf_freeblks += len;
 	be32_add_cpu(&agf->agf_freeblks, len);
 
 	xfs_trans_agblocks_delta(tp, len);
@@ -1175,8 +1174,7 @@ xfs_alloc_ag_vextent(
 	}
 
 	if (!args->wasfromfl) {
-		error = xfs_alloc_update_counters(args->tp, args->pag,
-						  args->agbp,
+		error = xfs_alloc_update_counters(args->tp, args->agbp,
 						  -((long)(args->len)));
 		if (error)
 			return error;
@@ -1887,7 +1885,6 @@ xfs_free_ag_extent(
 	enum xfs_ag_resv_type		type)
 {
 	struct xfs_mount		*mp;
-	struct xfs_perag		*pag;
 	struct xfs_btree_cur		*bno_cur;
 	struct xfs_btree_cur		*cnt_cur;
 	xfs_agblock_t			gtbno; /* start of right neighbor */
@@ -2167,10 +2164,8 @@ xfs_free_ag_extent(
 	/*
 	 * Update the freespace totals in the ag and superblock.
 	 */
-	pag = xfs_perag_get(mp, agno);
-	error = xfs_alloc_update_counters(tp, pag, agbp, len);
-	xfs_ag_resv_free_extent(pag, type, tp, len);
-	xfs_perag_put(pag);
+	error = xfs_alloc_update_counters(tp, agbp, len);
+	xfs_ag_resv_free_extent(agbp->b_pag, type, tp, len);
 	if (error)
 		goto error0;
 
@@ -2689,7 +2684,7 @@ xfs_alloc_get_freelist(
 	if (be32_to_cpu(agf->agf_flfirst) == xfs_agfl_size(mp))
 		agf->agf_flfirst = 0;
 
-	pag = xfs_perag_get(mp, be32_to_cpu(agf->agf_seqno));
+	pag = agbp->b_pag;
 	ASSERT(!pag->pagf_agflreset);
 	be32_add_cpu(&agf->agf_flcount, -1);
 	xfs_trans_agflist_delta(tp, -1);
@@ -2701,7 +2696,6 @@ xfs_alloc_get_freelist(
 		pag->pagf_btreeblks++;
 		logflags |= XFS_AGF_BTREEBLKS;
 	}
-	xfs_perag_put(pag);
 
 	xfs_alloc_log_agf(tp, agbp, logflags);
 	*bnop = bno;
@@ -2797,7 +2791,7 @@ xfs_alloc_put_freelist(
 	if (be32_to_cpu(agf->agf_fllast) == xfs_agfl_size(mp))
 		agf->agf_fllast = 0;
 
-	pag = xfs_perag_get(mp, be32_to_cpu(agf->agf_seqno));
+	pag = agbp->b_pag;
 	ASSERT(!pag->pagf_agflreset);
 	be32_add_cpu(&agf->agf_flcount, 1);
 	xfs_trans_agflist_delta(tp, 1);
@@ -2809,7 +2803,6 @@ xfs_alloc_put_freelist(
 		pag->pagf_btreeblks--;
 		logflags |= XFS_AGF_BTREEBLKS;
 	}
-	xfs_perag_put(pag);
 
 	xfs_alloc_log_agf(tp, agbp, logflags);
 
@@ -3006,7 +2999,7 @@ xfs_alloc_read_agf(
 	ASSERT(!(*bpp)->b_error);
 
 	agf = (*bpp)->b_addr;
-	pag = xfs_perag_get(mp, agno);
+	pag = (*bpp)->b_pag;
 	if (!pag->pagf_init) {
 		pag->pagf_freeblks = be32_to_cpu(agf->agf_freeblks);
 		pag->pagf_btreeblks = be32_to_cpu(agf->agf_btreeblks);
@@ -3034,7 +3027,6 @@ xfs_alloc_read_agf(
 		       be32_to_cpu(agf->agf_levels[XFS_BTNUM_CNTi]));
 	}
 #endif
-	xfs_perag_put(pag);
 	return 0;
 }
 
diff --git a/fs/xfs/libxfs/xfs_alloc_btree.c b/fs/xfs/libxfs/xfs_alloc_btree.c
index 60c453cb3ee3..c1d276f791ea 100644
--- a/fs/xfs/libxfs/xfs_alloc_btree.c
+++ b/fs/xfs/libxfs/xfs_alloc_btree.c
@@ -38,16 +38,15 @@ xfs_allocbt_set_root(
 {
 	struct xfs_buf		*agbp = cur->bc_ag.agbp;
 	struct xfs_agf		*agf = agbp->b_addr;
-	xfs_agnumber_t		seqno = be32_to_cpu(agf->agf_seqno);
 	int			btnum = cur->bc_btnum;
-	struct xfs_perag	*pag = xfs_perag_get(cur->bc_mp, seqno);
+	struct xfs_perag	*pag = agbp->b_pag;
 
 	ASSERT(ptr->s != 0);
+	ASSERT(pag->pag_agno == be32_to_cpu(agf->agf_seqno));
 
 	agf->agf_roots[btnum] = ptr->s;
 	be32_add_cpu(&agf->agf_levels[btnum], inc);
 	pag->pagf_levels[btnum] += inc;
-	xfs_perag_put(pag);
 
 	xfs_alloc_log_agf(cur->bc_tp, agbp, XFS_AGF_ROOTS | XFS_AGF_LEVELS);
 }
@@ -115,7 +114,6 @@ xfs_allocbt_update_lastrec(
 	int			reason)
 {
 	struct xfs_agf		*agf = cur->bc_ag.agbp->b_addr;
-	xfs_agnumber_t		seqno = be32_to_cpu(agf->agf_seqno);
 	struct xfs_perag	*pag;
 	__be32			len;
 	int			numrecs;
@@ -160,9 +158,9 @@ xfs_allocbt_update_lastrec(
 	}
 
 	agf->agf_longest = len;
-	pag = xfs_perag_get(cur->bc_mp, seqno);
+	pag = cur->bc_ag.agbp->b_pag;
+	ASSERT(pag->pag_agno == be32_to_cpu(agf->agf_seqno));
 	pag->pagf_longest = be32_to_cpu(len);
-	xfs_perag_put(pag);
 	xfs_alloc_log_agf(cur->bc_tp, cur->bc_ag.agbp, XFS_AGF_LONGEST);
 }
 
diff --git a/fs/xfs/libxfs/xfs_ialloc.c b/fs/xfs/libxfs/xfs_ialloc.c
index 7fcf62b324b0..f742a96a2fe1 100644
--- a/fs/xfs/libxfs/xfs_ialloc.c
+++ b/fs/xfs/libxfs/xfs_ialloc.c
@@ -888,10 +888,9 @@ xfs_ialloc_ag_alloc(
 	 */
 	be32_add_cpu(&agi->agi_count, newlen);
 	be32_add_cpu(&agi->agi_freecount, newlen);
-	pag = xfs_perag_get(args.mp, agno);
+	pag = agbp->b_pag;
 	pag->pagi_freecount += newlen;
 	pag->pagi_count += newlen;
-	xfs_perag_put(pag);
 	agi->agi_newino = cpu_to_be32(newino);
 
 	/*
@@ -1134,7 +1133,7 @@ xfs_dialloc_ag_inobt(
 	xfs_agnumber_t		agno = be32_to_cpu(agi->agi_seqno);
 	xfs_agnumber_t		pagno = XFS_INO_TO_AGNO(mp, parent);
 	xfs_agino_t		pagino = XFS_INO_TO_AGINO(mp, parent);
-	struct xfs_perag	*pag;
+	struct xfs_perag	*pag = agbp->b_pag;
 	struct xfs_btree_cur	*cur, *tcur;
 	struct xfs_inobt_rec_incore rec, trec;
 	xfs_ino_t		ino;
@@ -1143,8 +1142,6 @@ xfs_dialloc_ag_inobt(
 	int			i, j;
 	int			searchdistance = 10;
 
-	pag = xfs_perag_get(mp, agno);
-
 	ASSERT(pag->pagi_init);
 	ASSERT(pag->pagi_inodeok);
 	ASSERT(pag->pagi_freecount > 0);
@@ -1384,14 +1381,12 @@ xfs_dialloc_ag_inobt(
 
 	xfs_btree_del_cursor(cur, XFS_BTREE_NOERROR);
 	xfs_trans_mod_sb(tp, XFS_TRANS_SB_IFREE, -1);
-	xfs_perag_put(pag);
 	*inop = ino;
 	return 0;
 error1:
 	xfs_btree_del_cursor(tcur, XFS_BTREE_ERROR);
 error0:
 	xfs_btree_del_cursor(cur, XFS_BTREE_ERROR);
-	xfs_perag_put(pag);
 	return error;
 }
 
@@ -1587,7 +1582,6 @@ xfs_dialloc_ag(
 	xfs_agnumber_t			agno = be32_to_cpu(agi->agi_seqno);
 	xfs_agnumber_t			pagno = XFS_INO_TO_AGNO(mp, parent);
 	xfs_agino_t			pagino = XFS_INO_TO_AGINO(mp, parent);
-	struct xfs_perag		*pag;
 	struct xfs_btree_cur		*cur;	/* finobt cursor */
 	struct xfs_btree_cur		*icur;	/* inobt cursor */
 	struct xfs_inobt_rec_incore	rec;
@@ -1599,8 +1593,6 @@ xfs_dialloc_ag(
 	if (!xfs_sb_version_hasfinobt(&mp->m_sb))
 		return xfs_dialloc_ag_inobt(tp, agbp, parent, inop);
 
-	pag = xfs_perag_get(mp, agno);
-
 	/*
 	 * If pagino is 0 (this is the root inode allocation) use newino.
 	 * This must work because we've just allocated some.
@@ -1667,7 +1659,7 @@ xfs_dialloc_ag(
 	 */
 	be32_add_cpu(&agi->agi_freecount, -1);
 	xfs_ialloc_log_agi(tp, agbp, XFS_AGI_FREECOUNT);
-	pag->pagi_freecount--;
+	agbp->b_pag->pagi_freecount--;
 
 	xfs_trans_mod_sb(tp, XFS_TRANS_SB_IFREE, -1);
 
@@ -1680,7 +1672,6 @@ xfs_dialloc_ag(
 
 	xfs_btree_del_cursor(icur, XFS_BTREE_NOERROR);
 	xfs_btree_del_cursor(cur, XFS_BTREE_NOERROR);
-	xfs_perag_put(pag);
 	*inop = ino;
 	return 0;
 
@@ -1688,7 +1679,6 @@ xfs_dialloc_ag(
 	xfs_btree_del_cursor(icur, XFS_BTREE_ERROR);
 error_cur:
 	xfs_btree_del_cursor(cur, XFS_BTREE_ERROR);
-	xfs_perag_put(pag);
 	return error;
 }
 
@@ -1945,7 +1935,6 @@ xfs_difree_inobt(
 {
 	struct xfs_agi			*agi = agbp->b_addr;
 	xfs_agnumber_t			agno = be32_to_cpu(agi->agi_seqno);
-	struct xfs_perag		*pag;
 	struct xfs_btree_cur		*cur;
 	struct xfs_inobt_rec_incore	rec;
 	int				ilen;
@@ -2007,6 +1996,8 @@ xfs_difree_inobt(
 	if (!(mp->m_flags & XFS_MOUNT_IKEEP) &&
 	    rec.ir_free == XFS_INOBT_ALL_FREE &&
 	    mp->m_sb.sb_inopblock <= XFS_INODES_PER_CHUNK) {
+		struct xfs_perag	*pag = agbp->b_pag;
+
 		xic->deleted = true;
 		xic->first_ino = XFS_AGINO_TO_INO(mp, agno, rec.ir_startino);
 		xic->alloc = xfs_inobt_irec_to_allocmask(&rec);
@@ -2020,10 +2011,8 @@ xfs_difree_inobt(
 		be32_add_cpu(&agi->agi_count, -ilen);
 		be32_add_cpu(&agi->agi_freecount, -(ilen - 1));
 		xfs_ialloc_log_agi(tp, agbp, XFS_AGI_COUNT | XFS_AGI_FREECOUNT);
-		pag = xfs_perag_get(mp, agno);
 		pag->pagi_freecount -= ilen - 1;
 		pag->pagi_count -= ilen;
-		xfs_perag_put(pag);
 		xfs_trans_mod_sb(tp, XFS_TRANS_SB_ICOUNT, -ilen);
 		xfs_trans_mod_sb(tp, XFS_TRANS_SB_IFREE, -(ilen - 1));
 
@@ -2049,9 +2038,7 @@ xfs_difree_inobt(
 		 */
 		be32_add_cpu(&agi->agi_freecount, 1);
 		xfs_ialloc_log_agi(tp, agbp, XFS_AGI_FREECOUNT);
-		pag = xfs_perag_get(mp, agno);
-		pag->pagi_freecount++;
-		xfs_perag_put(pag);
+		agbp->b_pag->pagi_freecount++;
 		xfs_trans_mod_sb(tp, XFS_TRANS_SB_IFREE, 1);
 	}
 
@@ -2661,7 +2648,7 @@ xfs_ialloc_read_agi(
 		return error;
 
 	agi = (*bpp)->b_addr;
-	pag = xfs_perag_get(mp, agno);
+	pag = (*bpp)->b_pag;
 	if (!pag->pagi_init) {
 		pag->pagi_freecount = be32_to_cpu(agi->agi_freecount);
 		pag->pagi_count = be32_to_cpu(agi->agi_count);
@@ -2674,7 +2661,6 @@ xfs_ialloc_read_agi(
 	 */
 	ASSERT(pag->pagi_freecount == be32_to_cpu(agi->agi_freecount) ||
 		XFS_FORCED_SHUTDOWN(mp));
-	xfs_perag_put(pag);
 	return 0;
 }
 
diff --git a/fs/xfs/libxfs/xfs_refcount_btree.c b/fs/xfs/libxfs/xfs_refcount_btree.c
index 7fd6044a4f78..f445a8e2d04e 100644
--- a/fs/xfs/libxfs/xfs_refcount_btree.c
+++ b/fs/xfs/libxfs/xfs_refcount_btree.c
@@ -37,15 +37,14 @@ xfs_refcountbt_set_root(
 {
 	struct xfs_buf		*agbp = cur->bc_ag.agbp;
 	struct xfs_agf		*agf = agbp->b_addr;
-	xfs_agnumber_t		seqno = be32_to_cpu(agf->agf_seqno);
-	struct xfs_perag	*pag = xfs_perag_get(cur->bc_mp, seqno);
+	struct xfs_perag	*pag = agbp->b_pag;
 
 	ASSERT(ptr->s != 0);
+	ASSERT(pag->pag_agno == be32_to_cpu(agf->agf_seqno));
 
 	agf->agf_refcount_root = ptr->s;
 	be32_add_cpu(&agf->agf_refcount_level, inc);
 	pag->pagf_refcount_level += inc;
-	xfs_perag_put(pag);
 
 	xfs_alloc_log_agf(cur->bc_tp, agbp,
 			XFS_AGF_REFCOUNT_ROOT | XFS_AGF_REFCOUNT_LEVEL);
diff --git a/fs/xfs/libxfs/xfs_rmap_btree.c b/fs/xfs/libxfs/xfs_rmap_btree.c
index b7c05314d07c..959d9df1964e 100644
--- a/fs/xfs/libxfs/xfs_rmap_btree.c
+++ b/fs/xfs/libxfs/xfs_rmap_btree.c
@@ -63,16 +63,15 @@ xfs_rmapbt_set_root(
 {
 	struct xfs_buf		*agbp = cur->bc_ag.agbp;
 	struct xfs_agf		*agf = agbp->b_addr;
-	xfs_agnumber_t		seqno = be32_to_cpu(agf->agf_seqno);
 	int			btnum = cur->bc_btnum;
-	struct xfs_perag	*pag = xfs_perag_get(cur->bc_mp, seqno);
+	struct xfs_perag	*pag = agbp->b_pag;
 
 	ASSERT(ptr->s != 0);
+	ASSERT(pag->pag_agno == be32_to_cpu(agf->agf_seqno));
 
 	agf->agf_roots[btnum] = ptr->s;
 	be32_add_cpu(&agf->agf_levels[btnum], inc);
 	pag->pagf_levels[btnum] += inc;
-	xfs_perag_put(pag);
 
 	xfs_alloc_log_agf(cur->bc_tp, agbp, XFS_AGF_ROOTS | XFS_AGF_LEVELS);
 }
diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
index 64f5f9a440ae..d0e7db7a2c32 100644
--- a/fs/xfs/xfs_inode.c
+++ b/fs/xfs/xfs_inode.c
@@ -2248,7 +2248,6 @@ xfs_iunlink(
 	}
 
 	if (next_agino != NULLAGINO) {
-		struct xfs_perag	*pag;
 		xfs_agino_t		old_agino;
 
 		/*
@@ -2265,9 +2264,7 @@ xfs_iunlink(
 		 * agino has been unlinked, add a backref from the next inode
 		 * back to agino.
 		 */
-		pag = xfs_perag_get(mp, agno);
-		error = xfs_iunlink_add_backref(pag, agino, next_agino);
-		xfs_perag_put(pag);
+		error = xfs_iunlink_add_backref(agibp->b_pag, agino, next_agino);
 		if (error)
 			return error;
 	}
@@ -2403,7 +2400,6 @@ xfs_iunlink_remove(
 	struct xfs_buf		*agibp;
 	struct xfs_buf		*last_ibp;
 	struct xfs_dinode	*last_dip = NULL;
-	struct xfs_perag	*pag = NULL;
 	xfs_agnumber_t		agno = XFS_INO_TO_AGNO(mp, ip->i_ino);
 	xfs_agino_t		agino = XFS_INO_TO_AGINO(mp, ip->i_ino);
 	xfs_agino_t		next_agino;
@@ -2447,32 +2443,22 @@ xfs_iunlink_remove(
 	 * this inode's backref to point from the next inode.
 	 */
 	if (next_agino != NULLAGINO) {
-		pag = xfs_perag_get(mp, agno);
-		error = xfs_iunlink_change_backref(pag, next_agino,
+		error = xfs_iunlink_change_backref(agibp->b_pag, next_agino,
 				NULLAGINO);
 		if (error)
-			goto out;
+			return error;
 	}
 
-	if (head_agino == agino) {
-		/* Point the head of the list to the next unlinked inode. */
-		error = xfs_iunlink_update_bucket(tp, agno, agibp, bucket_index,
-				next_agino);
-		if (error)
-			goto out;
-	} else {
+	if (head_agino != agino) {
 		struct xfs_imap	imap;
 		xfs_agino_t	prev_agino;
 
-		if (!pag)
-			pag = xfs_perag_get(mp, agno);
-
 		/* We need to search the list for the inode being freed. */
 		error = xfs_iunlink_map_prev(tp, agno, head_agino, agino,
 				&prev_agino, &imap, &last_dip, &last_ibp,
-				pag);
+				agibp->b_pag);
 		if (error)
-			goto out;
+			return error;
 
 		/* Point the previous inode on the list to the next inode. */
 		xfs_iunlink_update_dinode(tp, agno, prev_agino, last_ibp,
@@ -2486,15 +2472,13 @@ xfs_iunlink_remove(
 		 * change_backref takes care of deleting the backref if
 		 * next_agino is NULLAGINO.
 		 */
-		error = xfs_iunlink_change_backref(pag, agino, next_agino);
-		if (error)
-			goto out;
+		return xfs_iunlink_change_backref(agibp->b_pag, agino,
+				next_agino);
 	}
 
-out:
-	if (pag)
-		xfs_perag_put(pag);
-	return error;
+	/* Point the head of the list to the next unlinked inode. */
+	return xfs_iunlink_update_bucket(tp, agno, agibp, bucket_index,
+			next_agino);
 }
 
 /*
-- 
2.18.1