xfs: skip verification on initial "guess" superblock read

[firefly-linux-kernel-4.4.55.git] / fs / xfs / xfs_sb.c

diff --git a/fs/xfs/xfs_sb.c b/fs/xfs/xfs_sb.c
index 1b0a6420f1b8d5637057a640df90deb3d887397f..359b19a4df42d85c9f9f55f33b77a610e06c082c 100644 (file)
--- a/fs/xfs/xfs_sb.c
+++ b/fs/xfs/xfs_sb.c
@@ -17,35 +17,26 @@
  */
 #include "xfs.h"
 #include "xfs_fs.h"
+#include "xfs_shared.h"
 #include "xfs_format.h"
 #include "xfs_log_format.h"
 #include "xfs_trans_resv.h"
 #include "xfs_bit.h"
-#include "xfs_inum.h"
 #include "xfs_sb.h"
 #include "xfs_ag.h"
 #include "xfs_mount.h"
-#include "xfs_da_format.h"
-#include "xfs_da_btree.h"
-#include "xfs_dir2.h"
-#include "xfs_bmap_btree.h"
-#include "xfs_alloc_btree.h"
-#include "xfs_ialloc_btree.h"
-#include "xfs_dinode.h"
 #include "xfs_inode.h"
-#include "xfs_btree.h"
 #include "xfs_ialloc.h"
 #include "xfs_alloc.h"
-#include "xfs_rtalloc.h"
-#include "xfs_bmap.h"
 #include "xfs_error.h"
-#include "xfs_quota.h"
-#include "xfs_fsops.h"
 #include "xfs_trace.h"
 #include "xfs_cksum.h"
 #include "xfs_trans.h"
-#include "xfs_trans_priv.h"
 #include "xfs_buf_item.h"
+#include "xfs_dinode.h"
+#include "xfs_bmap_btree.h"
+#include "xfs_alloc_btree.h"
+#include "xfs_ialloc_btree.h"
 
 /*
  * Physical superblock buffer manipulations. Shared with libxfs in userspace.
@@ -597,6 +588,11 @@ xfs_sb_verify(
  * single bit error could clear the feature bit and unused parts of the
  * superblock are supposed to be zero. Hence a non-null crc field indicates that
  * we've potentially lost a feature bit and we should check it anyway.
+ *
+ * However, past bugs (i.e. in growfs) left non-zeroed regions beyond the
+ * last field in V4 secondary superblocks.  So for secondary superblocks,
+ * we are more forgiving, and ignore CRC failures if the primary doesn't
+ * indicate that the fs version is V5.
  */
 static void
 xfs_sb_read_verify(
@@ -615,10 +611,14 @@ xfs_sb_read_verify(
                                                XFS_SB_VERSION_5) ||
             dsb->sb_crc != 0)) {
 
-               if (!xfs_verify_cksum(bp->b_addr, be16_to_cpu(dsb->sb_sectsize),
+               if (!xfs_verify_cksum(bp->b_addr, BBTOB(bp->b_length),
                                      offsetof(struct xfs_sb, sb_crc))) {
-                       error = EFSCORRUPTED;
-                       goto out_error;
+                       /* Only fail bad secondaries on a known V5 filesystem */
+                       if (bp->b_bn == XFS_SB_DADDR ||
+                           xfs_sb_version_hascrc(&mp->m_sb)) {
+                               error = EFSCORRUPTED;
+                               goto out_error;
+                       }
                }
        }
        error = xfs_sb_verify(bp, true);
@@ -644,7 +644,6 @@ xfs_sb_quiet_read_verify(
 {
        struct xfs_dsb  *dsb = XFS_BUF_TO_SBP(bp);
 
-
        if (dsb->sb_magicnum == cpu_to_be32(XFS_SB_MAGIC)) {
                /* XFS filesystem, verify noisily! */
                xfs_sb_read_verify(bp);