From a0e00751052b06508f6cfe4a434ebf2e1a04bf07 Mon Sep 17 00:00:00 2001 From: Michal Humpula 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 --- 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 */ #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