xfs: convert remaining direct references to m_perag

Convert the remaining direct lookups of the per ag structures to use
get/put accesses. Ensure that the loops across AGs and prior users
of the interface balance gets and puts correctly.

Signed-off-by: Dave Chinner <david@fromorbit.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Alex Elder <aelder@sgi.com>

4 files changed, 42 insertions, 15 deletions

diff --git a/fs/xfs/xfs_bmap.c b/fs/xfs/xfs_bmap.c
index 98251cdc52aa..a9b95d9cf2ad 100644
--- a/fs/xfs/xfs_bmap.c
+++ b/fs/xfs/xfs_bmap.c
@@ -2630,11 +2630,12 @@ xfs_bmap_btalloc(
                         startag = ag = 0;
                 notinit = 0;
                 down_read(&mp->m_peraglock);
+                pag = xfs_perag_get(mp, ag);
                 while (blen < ap->alen) {
-                        pag = &mp->m_perag[ag];
                         if (!pag->pagf_init &&
                             (error = xfs_alloc_pagf_init(mp, args.tp,
                                     ag, XFS_ALLOC_FLAG_TRYLOCK))) {
+                                xfs_perag_put(pag);
                                 up_read(&mp->m_peraglock);
                                 return error;
                         }
@@ -2667,6 +2668,7 @@ xfs_bmap_btalloc(
                                                 break;
 
                                         error = xfs_filestream_new_ag(ap, &ag);
+                                        xfs_perag_put(pag);
                                         if (error) {
                                                 up_read(&mp->m_peraglock);
                                                 return error;
@@ -2674,6 +2676,7 @@ xfs_bmap_btalloc(
 
                                         /* loop again to set 'blen'*/
                                         startag = NULLAGNUMBER;
+                                        pag = xfs_perag_get(mp, ag);
                                         continue;
                                 }
                         }
@@ -2681,7 +2684,10 @@ xfs_bmap_btalloc(
                                 ag = 0;
                         if (ag == startag)
                                 break;
+                        xfs_perag_put(pag);
+                        pag = xfs_perag_get(mp, ag);
                 }
+                xfs_perag_put(pag);
                 up_read(&mp->m_peraglock);
                 /*
                  * Since the above loop did a BUF_TRYLOCK, it is
diff --git a/fs/xfs/xfs_ialloc.c b/fs/xfs/xfs_ialloc.c
index cb907ba69c4c..884ee1367f46 100644
--- a/fs/xfs/xfs_ialloc.c
+++ b/fs/xfs/xfs_ialloc.c
@@ -253,6 +253,7 @@ xfs_ialloc_ag_alloc(
         xfs_agino_t     thisino;        /* current inode number, for loop */
         int             isaligned = 0;  /* inode allocation at stripe unit */
                                         /* boundary */
+        struct xfs_perag *pag;
 
         args.tp = tp;
         args.mp = tp->t_mountp;
@@ -383,7 +384,9 @@ xfs_ialloc_ag_alloc(
         be32_add_cpu(&agi->agi_count, newlen);
         be32_add_cpu(&agi->agi_freecount, newlen);
         down_read(&args.mp->m_peraglock);
-        args.mp->m_perag[agno].pagi_freecount += newlen;
+        pag = xfs_perag_get(args.mp, agno);
+        pag->pagi_freecount += newlen;
+        xfs_perag_put(pag);
         up_read(&args.mp->m_peraglock);
         agi->agi_newino = cpu_to_be32(newino);
 
@@ -488,7 +491,7 @@ xfs_ialloc_ag_select(
         flags = XFS_ALLOC_FLAG_TRYLOCK;
         down_read(&mp->m_peraglock);
         for (;;) {
-                pag = &mp->m_perag[agno];
+                pag = xfs_perag_get(mp, agno);
                 if (!pag->pagi_init) {
                         if (xfs_ialloc_read_agi(mp, tp, agno, &agbp)) {
                                 agbp = NULL;
@@ -527,6 +530,7 @@ xfs_ialloc_ag_select(
                                         agbp = NULL;
                                         goto nextag;
                                 }
+                                xfs_perag_put(pag);
                                 up_read(&mp->m_peraglock);
                                 return agbp;
                         }
@@ -535,6 +539,7 @@ unlock_nextag:
                 if (agbp)
                         xfs_trans_brelse(tp, agbp);
 nextag:
+                xfs_perag_put(pag);
                 /*
                  * No point in iterating over the rest, if we're shutting
                  * down.
@@ -672,6 +677,7 @@ xfs_dialloc(
         xfs_agnumber_t  tagno;          /* testing allocation group number */
         xfs_btree_cur_t *tcur;          /* temp cursor */
         xfs_inobt_rec_incore_t trec;    /* temp inode allocation record */
+        struct xfs_perag *pag;
 
 
         if (*IO_agbp == NULL) {
@@ -772,11 +778,14 @@ nextag:
                         return noroom ? ENOSPC : 0;
                 }
                 down_read(&mp->m_peraglock);
-                if (mp->m_perag[tagno].pagi_inodeok == 0) {
+                pag = xfs_perag_get(mp, tagno);
+                if (pag->pagi_inodeok == 0) {
+                        xfs_perag_put(pag);
                         up_read(&mp->m_peraglock);
                         goto nextag;
                 }
                 error = xfs_ialloc_read_agi(mp, tp, tagno, &agbp);
+                xfs_perag_put(pag);
                 up_read(&mp->m_peraglock);
                 if (error)
                         goto nextag;
@@ -790,6 +799,7 @@ nextag:
          */
         agno = tagno;
         *IO_agbp = NULL;
+        pag = xfs_perag_get(mp, agno);
 
  restart_pagno:
         cur = xfs_inobt_init_cursor(mp, tp, agbp, be32_to_cpu(agi->agi_seqno));
@@ -808,7 +818,6 @@ nextag:
          * If in the same AG as the parent, try to get near the parent.
          */
         if (pagno == agno) {
-                xfs_perag_t     *pag = &mp->m_perag[agno];
                 int             doneleft;       /* done, to the left */
                 int             doneright;      /* done, to the right */
                 int             searchdistance = 10;
@@ -1007,7 +1016,7 @@ alloc_inode:
         be32_add_cpu(&agi->agi_freecount, -1);
         xfs_ialloc_log_agi(tp, agbp, XFS_AGI_FREECOUNT);
         down_read(&mp->m_peraglock);
-        mp->m_perag[tagno].pagi_freecount--;
+        pag->pagi_freecount--;
         up_read(&mp->m_peraglock);
 
         error = xfs_check_agi_freecount(cur, agi);
@@ -1016,12 +1025,14 @@ alloc_inode:
 
         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;
 }
 
@@ -1052,6 +1063,7 @@ xfs_difree(
         xfs_mount_t     *mp;    /* mount structure for filesystem */
         int             off;    /* offset of inode in inode chunk */
         xfs_inobt_rec_incore_t rec;     /* btree record */
+        struct xfs_perag *pag;
 
         mp = tp->t_mountp;
 
@@ -1158,7 +1170,9 @@ xfs_difree(
                 be32_add_cpu(&agi->agi_freecount, -(ilen - 1));
                 xfs_ialloc_log_agi(tp, agbp, XFS_AGI_COUNT | XFS_AGI_FREECOUNT);
                 down_read(&mp->m_peraglock);
-                mp->m_perag[agno].pagi_freecount -= ilen - 1;
+                pag = xfs_perag_get(mp, agno);
+                pag->pagi_freecount -= ilen - 1;
+                xfs_perag_put(pag);
                 up_read(&mp->m_peraglock);
                 xfs_trans_mod_sb(tp, XFS_TRANS_SB_ICOUNT, -ilen);
                 xfs_trans_mod_sb(tp, XFS_TRANS_SB_IFREE, -(ilen - 1));
@@ -1189,7 +1203,9 @@ xfs_difree(
                 be32_add_cpu(&agi->agi_freecount, 1);
                 xfs_ialloc_log_agi(tp, agbp, XFS_AGI_FREECOUNT);
                 down_read(&mp->m_peraglock);
-                mp->m_perag[agno].pagi_freecount++;
+                pag = xfs_perag_get(mp, agno);
+                pag->pagi_freecount++;
+                xfs_perag_put(pag);
                 up_read(&mp->m_peraglock);
                 xfs_trans_mod_sb(tp, XFS_TRANS_SB_IFREE, 1);
         }
@@ -1379,7 +1395,6 @@ xfs_imap(
                         XFS_FSB_TO_BB(mp, mp->m_sb.sb_dblocks));
                 return XFS_ERROR(EINVAL);
         }
-
         return 0;
 }
 
@@ -1523,8 +1538,7 @@ xfs_ialloc_read_agi(
                 return error;
 
         agi = XFS_BUF_TO_AGI(*bpp);
-        pag = &mp->m_perag[agno];
-
+        pag = xfs_perag_get(mp, agno);
         if (!pag->pagi_init) {
                 pag->pagi_freecount = be32_to_cpu(agi->agi_freecount);
                 pag->pagi_count = be32_to_cpu(agi->agi_count);
@@ -1537,6 +1551,7 @@ 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/xfs_inode.c b/fs/xfs/xfs_inode.c
index bd3d81636d51..0317b000ab44 100644
--- a/fs/xfs/xfs_inode.c
+++ b/fs/xfs/xfs_inode.c
@@ -2695,7 +2695,7 @@ xfs_iflush_cluster(
         ilist_size = inodes_per_cluster * sizeof(xfs_inode_t *);
         ilist = kmem_alloc(ilist_size, KM_MAYFAIL|KM_NOFS);
         if (!ilist)
-                return 0;
+                goto out_put;
 
         mask = ~(((XFS_INODE_CLUSTER_SIZE(mp) >> mp->m_sb.sb_inodelog)) - 1);
         first_index = XFS_INO_TO_AGINO(mp, ip->i_ino) & mask;
@@ -2764,6 +2764,8 @@ xfs_iflush_cluster(
 out_free:
         read_unlock(&pag->pag_ici_lock);
         kmem_free(ilist);
+out_put:
+        xfs_perag_put(pag);
         return 0;
 
 
@@ -2807,6 +2809,7 @@ cluster_corrupt_out:
          */
         xfs_iflush_abort(iq);
         kmem_free(ilist);
+        xfs_perag_put(pag);
         return XFS_ERROR(EFSCORRUPTED);
 }
 
diff --git a/fs/xfs/xfs_mount.c b/fs/xfs/xfs_mount.c
index eb403b40e120..9055b60730d0 100644
--- a/fs/xfs/xfs_mount.c
+++ b/fs/xfs/xfs_mount.c
@@ -438,18 +438,20 @@ xfs_initialize_perag(
                         }
 
                         /* This ag is preferred for inodes */
-                        pag = &mp->m_perag[index];
+                        pag = xfs_perag_get(mp, index);
                         pag->pagi_inodeok = 1;
                         if (index < max_metadata)
                                 pag->pagf_metadata = 1;
                         xfs_initialize_perag_icache(pag);
+                        xfs_perag_put(pag);
                 }
         } else {
                 /* Setup default behavior for smaller filesystems */
                 for (index = 0; index < agcount; index++) {
-                        pag = &mp->m_perag[index];
+                        pag = xfs_perag_get(mp, index);
                         pag->pagi_inodeok = 1;
                         xfs_initialize_perag_icache(pag);
+                        xfs_perag_put(pag);
                 }
         }
         return index;
@@ -731,12 +733,13 @@ xfs_initialize_perag_data(xfs_mount_t *mp, xfs_agnumber_t agcount)
                 error = xfs_ialloc_pagi_init(mp, NULL, index);
                 if (error)
                         return error;
-                pag = &mp->m_perag[index];
+                pag = xfs_perag_get(mp, index);
                 ifree += pag->pagi_freecount;
                 ialloc += pag->pagi_count;
                 bfree += pag->pagf_freeblks;
                 bfreelst += pag->pagf_flcount;
                 btree += pag->pagf_btreeblks;
+                xfs_perag_put(pag);
         }
         /*
          * Overwrite incore superblock counters with just-read data