[XFS] Ensure maxagi not updated early during growfs, conflicts with

concurrent inode allocations.  Fix from ASANO Masahiro.

SGI Modid: xfs-linux:xfs-kern:177699a
Signed-off-by: Nathan Scott <nathans@sgi.com>

fs/xfs/xfs_fsops.c

@@ -142,6 +142,7 @@ xfs_growfs_data_private(
 	int			dpct;
 	int			error;
 	xfs_agnumber_t		nagcount;
+	xfs_agnumber_t		nagimax = 0;
 	xfs_rfsblock_t		nb, nb_mod;
 	xfs_rfsblock_t		new;
 	xfs_rfsblock_t		nfree;
@@ -183,7 +184,7 @@ xfs_growfs_data_private(
 		memset(&mp->m_perag[oagcount], 0,
 			(nagcount - oagcount) * sizeof(xfs_perag_t));
 		mp->m_flags |= XFS_MOUNT_32BITINODES;
-		xfs_initialize_perag(mp, nagcount);
+		nagimax = xfs_initialize_perag(mp, nagcount);
 		up_write(&mp->m_peraglock);
 	}
 	tp = xfs_trans_alloc(mp, XFS_TRANS_GROWFS);
@@ -372,6 +373,9 @@ xfs_growfs_data_private(
 	if (error) {
 		return error;
 	}
+	/* New allocation groups fully initialized, so update mount struct */
+	if (nagimax)
+		mp->m_maxagi = nagimax;
 	if (mp->m_sb.sb_imax_pct) {
 		__uint64_t icount = mp->m_sb.sb_dblocks * mp->m_sb.sb_imax_pct;
 		do_div(icount, 100);

fs/xfs/xfs_mount.c

@@ -318,10 +318,10 @@ xfs_mount_validate_sb(
 	return 0;
 }
 
-void
-xfs_initialize_perag(xfs_mount_t *mp, int agcount)
+xfs_agnumber_t
+xfs_initialize_perag(xfs_mount_t *mp, xfs_agnumber_t agcount)
 {
-	int		index, max_metadata;
+	xfs_agnumber_t	index, max_metadata;
 	xfs_perag_t	*pag;
 	xfs_agino_t	agino;
 	xfs_ino_t	ino;
@@ -377,7 +377,7 @@ xfs_initialize_perag(xfs_mount_t *mp, int agcount)
 			pag->pagi_inodeok = 1;
 		}
 	}
-	mp->m_maxagi = index;
+	return index;
 }
 
 /*
@@ -951,7 +951,7 @@ xfs_mountfs(
 	mp->m_perag =
 		kmem_zalloc(sbp->sb_agcount * sizeof(xfs_perag_t), KM_SLEEP);
 
-	xfs_initialize_perag(mp, sbp->sb_agcount);
+	mp->m_maxagi = xfs_initialize_perag(mp, sbp->sb_agcount);
 
 	/*
 	 * log's mount-time initialization. Perform 1st part recovery if needed

fs/xfs/xfs_mount.h

@@ -551,7 +551,7 @@ extern int	xfs_readsb(xfs_mount_t *mp);
 extern void	xfs_freesb(xfs_mount_t *);
 extern void	xfs_do_force_shutdown(bhv_desc_t *, int, char *, int);
 extern int	xfs_syncsub(xfs_mount_t *, int, int, int *);
-extern void	xfs_initialize_perag(xfs_mount_t *, int);
+extern xfs_agnumber_t	xfs_initialize_perag(xfs_mount_t *, xfs_agnumber_t);
 extern void	xfs_xlatesb(void *, struct xfs_sb *, int, xfs_arch_t,
 			__int64_t);