blkid: fix ZFS device detection

Fix the ZFS device detection by looking at multiple uberblocks to
see if any are present, rather than looking for the ZFS boot block
which is not always present.

There may be up to 128 uberblocks, but the first 4 are not written
to disk on a newly-formatted filesystem so check several of them at
different offsets within the uberblock array.

Signed-off-by: Andreas Dilger <adilger@whamcloud.com>

diff --git a/lib/blkid/probe.c b/lib/blkid/probe.c
index 6970b12..4eddeff 100644 (file)
--- a/lib/blkid/probe.c
+++ b/lib/blkid/probe.c
@@ -1435,10 +1435,19 @@ static struct blkid_magic type_array[] = {
   { "iso9660", 32,      1,  5, "CD001",                probe_iso9660 },
   { "iso9660", 32,      9,  5, "CDROM",                probe_iso9660 },
   { "jfs",     32,      0,  4, "JFS1",                 probe_jfs },
-  { "zfs",       8,     0,  8, "\0\0\x02\xf5\xb0\x07\xb1\x0c", probe_zfs },
-  { "zfs",       8,     0,  8, "\x0c\xb1\x07\xb0\xf5\x02\0\0", probe_zfs },
-  { "zfs",     264,     0,  8, "\0\0\x02\xf5\xb0\x07\xb1\x0c", probe_zfs },
-  { "zfs",     264,     0,  8, "\x0c\xb1\x07\xb0\xf5\x02\0\0", probe_zfs },
+  /* ZFS has 128 root blocks (#4 is the first used), check only 6 of them */
+  { "zfs",     128,     0,  8, "\0\0\0\0\0\xba\xb1\x0c", probe_zfs },
+  { "zfs",     128,     0,  8, "\x0c\xb1\xba\0\0\0\0\0", probe_zfs },
+  { "zfs",     132,     0,  8, "\0\0\0\0\0\xba\xb1\x0c", probe_zfs },
+  { "zfs",     132,     0,  8, "\x0c\xb1\xba\0\0\0\0\0", probe_zfs },
+  { "zfs",     136,     0,  8, "\0\0\0\0\0\xba\xb1\x0c", probe_zfs },
+  { "zfs",     136,     0,  8, "\x0c\xb1\xba\0\0\0\0\0", probe_zfs },
+  { "zfs",     384,     0,  8, "\0\0\0\0\0\xba\xb1\x0c", probe_zfs },
+  { "zfs",     384,     0,  8, "\x0c\xb1\xba\0\0\0\0\0", probe_zfs },
+  { "zfs",     388,     0,  8, "\0\0\0\0\0\xba\xb1\x0c", probe_zfs },
+  { "zfs",     388,     0,  8, "\x0c\xb1\xba\0\0\0\0\0", probe_zfs },
+  { "zfs",     392,     0,  8, "\0\0\0\0\0\xba\xb1\x0c", probe_zfs },
+  { "zfs",     392,     0,  8, "\x0c\xb1\xba\0\0\0\0\0", probe_zfs },
   { "hfsplus",  1,      0,  2, "BD",                   probe_hfsplus },
   { "hfsplus",  1,      0,  2, "H+",                   probe_hfsplus },
   { "hfsplus",  1,      0,  2, "HX",                   probe_hfsplus },

diff --git a/lib/blkid/probe.h b/lib/blkid/probe.h
index 37e80ef..4f1687e 100644 (file)
--- a/lib/blkid/probe.h
+++ b/lib/blkid/probe.h
@@ -194,6 +194,16 @@ struct jfs_super_block {
        unsigned char   js_loguuid[16];
 };
 
+#define UBERBLOCK_MAGIC         0x00bab10c              /* oo-ba-bloc!  */
+struct zfs_uberblock {
+       __u64           ub_magic;       /* UBERBLOCK_MAGIC              */
+       __u64           ub_version;     /* ZFS_VERSION                  */
+       __u64           ub_txg;         /* txg of last sync             */
+       __u64           ub_guid_sum;    /* sum of all vdev guids        */
+       __u64           ub_timestamp;   /* UTC time of last sync        */
+       char            ub_rootbp;      /* MOS objset_phys_t            */
+};
+
 struct romfs_super_block {
        unsigned char   ros_magic[8];
        __u32           ros_dummy1[2];