[XFS] Re-initialize the per-cpu superblock counters after recovery.

After filesystem recovery the superblock is re-read to bring in any
changes. If the per-cpu superblock counters are not re-initialized from
the superblock then the next time the per-cpu counters are disabled they
might overwrite the global counter with a bogus value.

SGI-PV: 957348
SGI-Modid: xfs-linux-melb:xfs-kern:27999a

Signed-off-by: Lachlan McIlroy <lachlan@sgi.com>
Signed-off-by: David Chinner <dgc@sgi.com>
Signed-off-by: Tim Shimmin <tes@sgi.com>

fs/xfs/xfs_log_recover.c

@@ -3848,6 +3848,9 @@ xlog_do_recover(
 	ASSERT(XFS_SB_GOOD_VERSION(sbp));
 	xfs_buf_relse(bp);
 
+	/* We've re-read the superblock so re-initialize per-cpu counters */
+	xfs_icsb_reinit_counters(log->l_mp);
+
 	xlog_recover_check_summary(log);
 
 	/* Normal transactions can now occur */

fs/xfs/xfs_mount.c

@@ -543,11 +543,8 @@ xfs_readsb(xfs_mount_t *mp, int flags)
 		ASSERT(XFS_BUF_VALUSEMA(bp) <= 0);
 	}
 
-	xfs_icsb_lock(mp);
-	xfs_icsb_balance_counter(mp, XFS_SBS_ICOUNT, 0, 0);
-	xfs_icsb_balance_counter(mp, XFS_SBS_IFREE, 0, 0);
-	xfs_icsb_balance_counter(mp, XFS_SBS_FDBLOCKS, 0, 0);
-	xfs_icsb_unlock(mp);
+	/* Initialize per-cpu counters */
+	xfs_icsb_reinit_counters(mp);
 
 	mp->m_sb_bp = bp;
 	xfs_buf_relse(bp);
@@ -1811,6 +1808,22 @@ xfs_icsb_init_counters(
 	return 0;
 }
 
+void
+xfs_icsb_reinit_counters(
+	xfs_mount_t	*mp)
+{
+	xfs_icsb_lock(mp);
+	/*
+	 * start with all counters disabled so that the
+	 * initial balance kicks us off correctly
+	 */
+	mp->m_icsb_counters = -1;
+	xfs_icsb_balance_counter(mp, XFS_SBS_ICOUNT, 0, 0);
+	xfs_icsb_balance_counter(mp, XFS_SBS_IFREE, 0, 0);
+	xfs_icsb_balance_counter(mp, XFS_SBS_FDBLOCKS, 0, 0);
+	xfs_icsb_unlock(mp);
+}
+
 STATIC void
 xfs_icsb_destroy_counters(
 	xfs_mount_t	*mp)

fs/xfs/xfs_mount.h

@@ -307,10 +307,12 @@ typedef struct xfs_icsb_cnts {
 #define XFS_ICSB_LAZY_COUNT	(1 << 1)	/* accuracy not needed */
 
 extern int	xfs_icsb_init_counters(struct xfs_mount *);
+extern void	xfs_icsb_reinit_counters(struct xfs_mount *);
 extern void	xfs_icsb_sync_counters_flags(struct xfs_mount *, int);
 
 #else
 #define xfs_icsb_init_counters(mp)	(0)
+#define xfs_icsb_reinit_counters(mp)	do { } while (0)
 #define xfs_icsb_sync_counters_flags(mp, flags)	do { } while (0)
 #endif