xfs_repair: new secondary superblock search method

Optimize secondary sb search, using similar method to find
fs geometry as that of xfs_mkfs. If this faster method fails
in finding a secondary sb, fall back to original brute force
slower search.

Signed-off-by: Bill O'Donnell <billodo@redhat.com>
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

diff --git a/Makefile b/Makefile
index d4db4f533d458fdd8dd641282e22453a6a225e26..7bdc670a25649bd56d06531917ec8c64208c8299 100644 (file)
--- a/Makefile
+++ b/Makefile
@@ -80,7 +80,7 @@ fsr: libhandle
 growfs: libxcmd
 io: libxcmd libhandle
 quota: libxcmd
-repair: libxlog
+repair: libxlog libxcmd
 copy: libxlog
 mkfs: libxcmd
 

diff --git a/repair/Makefile b/repair/Makefile
index 251722bb32de58ddff6d2dce10ad103fc116c530..3f12b5d364494705e1f199e3311d5571031b952e 100644 (file)
--- a/repair/Makefile
+++ b/repair/Makefile
@@ -20,8 +20,9 @@ CFILES = agheader.c attr_repair.c avl.c avl64.c bmap.c btree.c \
        progress.c prefetch.c rt.c sb.c scan.c threads.c \
        versions.c xfs_repair.c
 
-LLDLIBS = $(LIBXFS) $(LIBXLOG) $(LIBUUID) $(LIBRT) $(LIBPTHREAD)
-LTDEPENDENCIES = $(LIBXFS) $(LIBXLOG)
+LLDLIBS = $(LIBXFS) $(LIBXLOG) $(LIBXCMD) $(LIBUUID) \
+       $(LIBRT) $(LIBPTHREAD) $(LIBBLKID)
+LTDEPENDENCIES = $(LIBXFS) $(LIBXLOG) $(LIBXCMD)
 LLDFLAGS = -static-libtool-libs
 
 default: depend $(LTCOMMAND)

diff --git a/repair/sb.c b/repair/sb.c
index 4eef14af14a47d2e3214bd796571201f9c6cec24..7e4708c164462296494ad733632cb09683fc7992 100644 (file)
--- a/repair/sb.c
+++ b/repair/sb.c
@@ -17,6 +17,7 @@
  */
 
 #include "libxfs.h"
+#include "libxcmd.h"
 #include "libxlog.h"
 #include "agheader.h"
 #include "globals.h"
@@ -85,10 +86,15 @@ copy_sb(xfs_sb_t *source, xfs_sb_t *dest)
 }
 
 /*
- * find a secondary superblock, copy it into the sb buffer
+ * find a secondary superblock, copy it into the sb buffer.
+ * start is the point to begin reading BSIZE bytes.
+ * skip contains a byte-count of how far to advance for next read.
  */
-int
-find_secondary_sb(xfs_sb_t *rsb)
+static int
+__find_secondary_sb(
+       xfs_sb_t        *rsb,
+       __uint64_t      start,
+       __uint64_t      skip)
 {
        xfs_off_t       off;
        xfs_sb_t        *sb;
@@ -117,7 +123,7 @@ find_secondary_sb(xfs_sb_t *rsb)
        /*
         * skip first sector since we know that's bad
         */
-       for (done = 0, off = XFS_AG_MIN_BYTES; !done ; off += bsize)  {
+       for (done = 0, off = start; !done ; off += skip)  {
                /*
                 * read disk 1 MByte at a time.
                 */
@@ -166,7 +172,63 @@ find_secondary_sb(xfs_sb_t *rsb)
        }
 
        free(sb);
-       return(retval);
+       return retval;
+}
+
+static int
+guess_default_geometry(
+       __uint64_t              *agsize,
+       __uint64_t              *agcount,
+       libxfs_init_t           *x)
+{
+       struct fs_topology      ft;
+       int                     blocklog;
+       __uint64_t              dblocks;
+       int                     multidisk;
+
+       memset(&ft, 0, sizeof(ft));
+       get_topology(x, &ft, 1);
+
+       /*
+        * get geometry from get_topology result.
+        * Use default block size (2^12)
+        */
+       blocklog = 12;
+       multidisk = ft.dswidth | ft.dsunit;
+       dblocks = x->dsize >> (blocklog - BBSHIFT);
+       calc_default_ag_geometry(blocklog, dblocks, multidisk,
+                                agsize, agcount);
+
+       return blocklog;
+}
+
+int
+find_secondary_sb(xfs_sb_t *rsb)
+{
+       int             retval;
+       __uint64_t      agcount;
+       __uint64_t      agsize;
+       __uint64_t      skip;
+       int             blocklog;
+
+       /*
+        * Attempt to find secondary sb with a coarse approach.
+        * Failing that, fallback to a fine-grained approach.
+        */
+       blocklog = guess_default_geometry(&agsize, &agcount, &x);
+
+       /*
+        * use found ag geometry to quickly find secondary sb
+        */
+       skip = agsize << blocklog;
+       retval = __find_secondary_sb(rsb, skip, skip);
+       if (!retval)  {
+               /*
+                * fallback: Start at min agsize and scan all blocks
+                */
+               retval = __find_secondary_sb(rsb, XFS_AG_MIN_BYTES, BSIZE);
+       }
+       return retval;
 }
 
 /*