1 files changed, 34 insertions, 3 deletions

diff --git a/fs/xfs/xfs_sb.h b/fs/xfs/xfs_sb.h
index d3a59735009a..b1a83f8ec044 100644
--- a/fs/xfs/xfs_sb.h
+++ b/fs/xfs/xfs_sb.h
@@ -89,6 +89,7 @@ struct xfs_mount;
 
 /*
  * Superblock - in core version.  Must match the ondisk version below.
+ * Must be padded to 64 bit alignment.
  */
 typedef struct xfs_sb {
         __uint32_t      sb_magicnum;    /* magic number == XFS_SB_MAGIC */
@@ -145,10 +146,21 @@ typedef struct xfs_sb {
         __uint16_t      sb_logsectsize; /* sector size for the log, bytes */
         __uint32_t      sb_logsunit;    /* stripe unit size for the log */
         __uint32_t      sb_features2;   /* additional feature bits */
+
+        /*
+         * bad features2 field as a result of failing to pad the sb
+         * structure to 64 bits. Some machines will be using this field
+         * for features2 bits. Easiest just to mark it bad and not use
+         * it for anything else.
+         */
+        __uint32_t      sb_bad_features2;
+
+        /* must be padded to 64 bit alignment */
 } xfs_sb_t;
 
 /*
- * Superblock - on disk version.  Must match the in core version below.
+ * Superblock - on disk version.  Must match the in core version above.
+ * Must be padded to 64 bit alignment.
  */
 typedef struct xfs_dsb {
         __be32          sb_magicnum;    /* magic number == XFS_SB_MAGIC */
@@ -205,6 +217,15 @@ typedef struct xfs_dsb {
         __be16          sb_logsectsize; /* sector size for the log, bytes */
         __be32          sb_logsunit;    /* stripe unit size for the log */
         __be32          sb_features2;   /* additional feature bits */
+        /*
+         * bad features2 field as a result of failing to pad the sb
+         * structure to 64 bits. Some machines will be using this field
+         * for features2 bits. Easiest just to mark it bad and not use
+         * it for anything else.
+         */
+        __be32  sb_bad_features2;
+
+        /* must be padded to 64 bit alignment */
 } xfs_dsb_t;
 
 /*
@@ -223,7 +244,7 @@ typedef enum {
         XFS_SBS_GQUOTINO, XFS_SBS_QFLAGS, XFS_SBS_FLAGS, XFS_SBS_SHARED_VN,
         XFS_SBS_INOALIGNMT, XFS_SBS_UNIT, XFS_SBS_WIDTH, XFS_SBS_DIRBLKLOG,
         XFS_SBS_LOGSECTLOG, XFS_SBS_LOGSECTSIZE, XFS_SBS_LOGSUNIT,
-        XFS_SBS_FEATURES2,
+        XFS_SBS_FEATURES2, XFS_SBS_BAD_FEATURES2,
         XFS_SBS_FIELDCOUNT
 } xfs_sb_field_t;
 
@@ -248,13 +269,15 @@ typedef enum {
 #define XFS_SB_IFREE            XFS_SB_MVAL(IFREE)
 #define XFS_SB_FDBLOCKS         XFS_SB_MVAL(FDBLOCKS)
 #define XFS_SB_FEATURES2        XFS_SB_MVAL(FEATURES2)
+#define XFS_SB_BAD_FEATURES2    XFS_SB_MVAL(BAD_FEATURES2)
 #define XFS_SB_NUM_BITS         ((int)XFS_SBS_FIELDCOUNT)
 #define XFS_SB_ALL_BITS         ((1LL << XFS_SB_NUM_BITS) - 1)
 #define XFS_SB_MOD_BITS         \
         (XFS_SB_UUID | XFS_SB_ROOTINO | XFS_SB_RBMINO | XFS_SB_RSUMINO | \
          XFS_SB_VERSIONNUM | XFS_SB_UQUOTINO | XFS_SB_GQUOTINO | \
          XFS_SB_QFLAGS | XFS_SB_SHARED_VN | XFS_SB_UNIT | XFS_SB_WIDTH | \
-         XFS_SB_ICOUNT | XFS_SB_IFREE | XFS_SB_FDBLOCKS | XFS_SB_FEATURES2)
+         XFS_SB_ICOUNT | XFS_SB_IFREE | XFS_SB_FDBLOCKS | XFS_SB_FEATURES2 | \
+         XFS_SB_BAD_FEATURES2)
 
 
 /*
@@ -296,6 +319,14 @@ static inline int xfs_sb_good_version(xfs_sb_t *sbp)
 }
 #endif /* __KERNEL__ */
 
+/*
+ * Detect a bad features2 field
+ */
+static inline int xfs_sb_has_bad_features2(xfs_sb_t *sbp)
+{
+        return (sbp->sb_bad_features2 != 0);
+}
+
 static inline unsigned xfs_sb_version_tonew(unsigned v)
 {
         return ((((v) == XFS_SB_VERSION_1) ? \