[XFS] Fix superblock features2 field alignment problem

[sfrench/cifs-2.6.git] / fs / xfs / xfs_mount.c

diff --git a/fs/xfs/xfs_mount.c b/fs/xfs/xfs_mount.c
index 99bab1e372b1ce03e7932781a446577c00c8ce04..4e93c02faf24bb2e960b4c8a0395fa660d1ac347 100644 (file)
--- a/fs/xfs/xfs_mount.c
+++ b/fs/xfs/xfs_mount.c
@@ -44,7 +44,7 @@
 #include "xfs_quota.h"
 #include "xfs_fsops.h"
 
-STATIC void    xfs_mount_log_sbunit(xfs_mount_t *, __int64_t);
+STATIC void    xfs_mount_log_sb(xfs_mount_t *, __int64_t);
 STATIC int     xfs_uuid_mount(xfs_mount_t *);
 STATIC void    xfs_uuid_unmount(xfs_mount_t *mp);
 STATIC void    xfs_unmountfs_wait(xfs_mount_t *);
@@ -119,6 +119,7 @@ static const struct {
     { offsetof(xfs_sb_t, sb_logsectsize),0 },
     { offsetof(xfs_sb_t, sb_logsunit),  0 },
     { offsetof(xfs_sb_t, sb_features2),         0 },
+    { offsetof(xfs_sb_t, sb_bad_features2), 0 },
     { sizeof(xfs_sb_t),                         0 }
 };
 
@@ -449,6 +450,7 @@ xfs_sb_from_disk(
        to->sb_logsectsize = be16_to_cpu(from->sb_logsectsize);
        to->sb_logsunit = be32_to_cpu(from->sb_logsunit);
        to->sb_features2 = be32_to_cpu(from->sb_features2);
+       to->sb_bad_features2 = be32_to_cpu(from->sb_bad_features2);
 }
 
 /*
@@ -969,6 +971,26 @@ xfs_mountfs(
        }
        xfs_mount_common(mp, sbp);
 
+       /*
+        * Check for a bad features2 field alignment. This happened on
+        * some platforms due to xfs_sb_t not being 64bit size aligned
+        * when sb_features was added and hence the compiler put it in
+        * the wrong place.
+        *
+        * If we detect a bad field, we or the set bits into the existing
+        * features2 field in case it has already been modified and we
+        * don't want to lose any features. Zero the bad one and mark
+        * the two fields as needing updates once the transaction subsystem
+        * is online.
+        */
+       if (xfs_sb_has_bad_features2(sbp)) {
+               cmn_err(CE_WARN,
+                       "XFS: correcting sb_features alignment problem");
+               sbp->sb_features2 |= sbp->sb_bad_features2;
+               sbp->sb_bad_features2 = 0;
+               update_flags |= XFS_SB_FEATURES2 | XFS_SB_BAD_FEATURES2;
+       }
+
        /*
         * Check if sb_agblocks is aligned at stripe boundary
         * If sb_agblocks is NOT aligned turn off m_dalign since
@@ -1159,11 +1181,10 @@ xfs_mountfs(
        }
 
        /*
-        * If fs is not mounted readonly, then update the superblock
-        * unit and width changes.
+        * If fs is not mounted readonly, then update the superblock changes.
         */
        if (update_flags && !(mp->m_flags & XFS_MOUNT_RDONLY))
-               xfs_mount_log_sbunit(mp, update_flags);
+               xfs_mount_log_sb(mp, update_flags);
 
        /*
         * Initialise the XFS quota management subsystem for this mount
@@ -1878,13 +1899,14 @@ xfs_uuid_unmount(
  * be altered by the mount options. Only the first superblock is updated.
  */
 STATIC void
-xfs_mount_log_sbunit(
+xfs_mount_log_sb(
        xfs_mount_t     *mp,
        __int64_t       fields)
 {
        xfs_trans_t     *tp;
 
-       ASSERT(fields & (XFS_SB_UNIT|XFS_SB_WIDTH|XFS_SB_UUID));
+       ASSERT(fields & (XFS_SB_UNIT | XFS_SB_WIDTH | XFS_SB_UUID |
+                        XFS_SB_FEATURES2 | XFS_SB_BAD_FEATURES2));
 
        tp = xfs_trans_alloc(mp, XFS_TRANS_SB_UNIT);
        if (xfs_trans_reserve(tp, 0, mp->m_sb.sb_sectsize + 128, 0, 0,