[XFS] using a spinlock per cpu for superblock counter exclusion results in
a preēmpt counter overflow at 256p and above. Change the exclusion
mechanism to use atomic bit operations and busy wait loops to emulate the
spin lock exclusion mechanism but without the preempt count issues.
SGI-PV: 950027
SGI-Modid: xfs-linux-melb:xfs-kern:25338a
Signed-off-by: David Chinner <dgc@sgi.com>
Signed-off-by: Nathan Scott <nathans@sgi.com>
diff --git a/fs/xfs/xfs_mount.h b/fs/xfs/xfs_mount.h
index 9d2ffbd..29cfcf0 100644
--- a/fs/xfs/xfs_mount.h
+++ b/fs/xfs/xfs_mount.h
@@ -280,9 +280,11 @@
uint64_t icsb_fdblocks;
uint64_t icsb_ifree;
uint64_t icsb_icount;
- spinlock_t icsb_lock;
+ unsigned long icsb_flags;
} xfs_icsb_cnts_t;
+#define XFS_ICSB_FLAG_LOCK (1 << 0) /* counter lock bit */
+
#define XFS_ICSB_SB_LOCKED (1 << 0) /* sb already locked */
#define XFS_ICSB_LAZY_COUNT (1 << 1) /* accuracy not needed */