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From a0e00751052b06508f6cfe4a434ebf2e1a04bf07 Mon Sep 17 00:00:00 2001
From: Michal Humpula <michal.humpula@hudrydum.cz>
Date: Wed, 25 Feb 2015 20:25:05 +0100
Subject: [PATCH 108/116] blkid: make zfs detection more robust
Try to use all the possible uberblock locations.
Upstream: https://github.com/karelzak/util-linux/commit/5dd705ba65dc80cf8630b3b1b4f3a1ba153e7eec
Addresses: https://bugzilla.redhat.com/show_bug.cgi?id=1392661
Signed-off-by: Karel Zak <kzak@redhat.com>
---
libblkid/src/superblocks/zfs.c | 42 +++++++++++++++++++++++++++---------------
1 file changed, 27 insertions(+), 15 deletions(-)
diff --git a/libblkid/src/superblocks/zfs.c b/libblkid/src/superblocks/zfs.c
index 86da59d..4a64a03 100644
--- a/libblkid/src/superblocks/zfs.c
+++ b/libblkid/src/superblocks/zfs.c
@@ -19,6 +19,7 @@
#define VDEV_LABEL_UBERBLOCK (128 * 1024ULL)
#define VDEV_LABEL_NVPAIR ( 16 * 1024ULL)
#define VDEV_LABEL_SIZE (256 * 1024ULL)
+#define UBERBLOCK_SIZE 1024ULL
/* #include <sys/uberblock_impl.h> */
#define UBERBLOCK_MAGIC 0x00bab10c /* oo-ba-bloc! */
@@ -31,7 +32,7 @@ struct zfs_uberblock {
char ub_rootbp; /* MOS objset_phys_t */
} __attribute__((packed));
-#define ZFS_TRIES 64
+#define ZFS_TRIES 512
#define ZFS_WANT 4
#define DATA_TYPE_UINT64 8
@@ -162,11 +163,10 @@ static void zfs_extract_guid_name(blkid_probe pr, loff_t offset)
#define zdebug(fmt, ...) do {} while(0)
/*#define zdebug(fmt, a...) fprintf(stderr, fmt, ##a)*/
-/* ZFS has 128x1kB host-endian root blocks, stored in 2 areas at the start
- * of the disk, and 2 areas at the end of the disk. Check only some of them...
- * #4 (@ 132kB) is the first one written on a new filesystem. */
-static int probe_zfs(blkid_probe pr,
- const struct blkid_idmag *mag __attribute__((__unused__)))
+/* ZFS has 128x1kB host-endian root blocks, stored in 2 areas (labels)
+ * at the start of the disk, and 2 areas at the end of the disk.
+ */
+static int probe_zfs(blkid_probe pr, const struct blkid_idmag *mag)
{
uint64_t swab_magic = swab64(UBERBLOCK_MAGIC);
struct zfs_uberblock *ub;
@@ -174,15 +174,29 @@ static int probe_zfs(blkid_probe pr,
loff_t offset, ub_offset = 0;
int tried;
int found;
+ loff_t blk_align = (pr->size % (256 * 1024ULL));
zdebug("probe_zfs\n");
- /* Look for at least 4 uberblocks to ensure a positive match */
+ /* Look for at least 4 uberblocks to ensure a positive match.
+ Begin with Label 0 (L0) at the start of the block device. */
for (tried = found = 0, offset = VDEV_LABEL_UBERBLOCK;
- tried < ZFS_TRIES && found < ZFS_WANT;
- tried++, offset += 4096) {
- /* also try the second uberblock copy */
- if (tried == (ZFS_TRIES / 2))
+ found < ZFS_WANT && tried < ZFS_TRIES;
+ tried++, offset += UBERBLOCK_SIZE)
+ {
+ /* Leave L0 to try other labels */
+ switch(tried) {
+ case 128: // jump to L1, just after L0
offset = VDEV_LABEL_SIZE + VDEV_LABEL_UBERBLOCK;
+ break;
+ case 256: // jump to L2 near the far end of the block device
+ offset = pr->size - 2 * VDEV_LABEL_SIZE + VDEV_LABEL_UBERBLOCK - blk_align;
+ zdebug("probe_zfs: l2 offset %llu\n", offset >> 10);
+ break;
+ case 384: // jump to L3 at the furthest end of the block device
+ offset = pr->size - VDEV_LABEL_SIZE + VDEV_LABEL_UBERBLOCK - blk_align;
+ zdebug("probe_zfs: l3 offset %llu\n", offset >> 10);
+ break;
+ }
ub = (struct zfs_uberblock *)
blkid_probe_get_buffer(pr, offset,
@@ -193,15 +207,14 @@ static int probe_zfs(blkid_probe pr,
if (ub->ub_magic == UBERBLOCK_MAGIC) {
ub_offset = offset;
found++;
+ zdebug("probe_zfs: found little-endian uberblock at %llu\n", offset >> 10);
}
if ((swab_endian = (ub->ub_magic == swab_magic))) {
ub_offset = offset;
found++;
+ zdebug("probe_zfs: found big-endian uberblock at %llu\n", offset >> 10);
}
-
- zdebug("probe_zfs: found %s-endian uberblock at %llu\n",
- swab_endian ? "big" : "little", offset >> 10);
}
if (found < 4)
@@ -230,4 +243,3 @@ const struct blkid_idinfo zfs_idinfo =
.minsz = 64 * 1024 * 1024,
.magics = BLKID_NONE_MAGIC
};
-
--
2.9.3