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authorEd Bartosh <ed.bartosh@linux.intel.com>2016-04-28 13:58:04 +0300
committerRichard Purdie <richard.purdie@linuxfoundation.org>2016-05-06 10:30:55 +0100
commitd2d0d18dfd3922411d856b98ab6ba5d64c9c1c9f (patch)
tree8eee021923517a4e9b01d456c813860f8887e8cb
parent27fd1bb7969b558864463450e1837c4400a03f9c (diff)
downloadopenembedded-core-contrib-d2d0d18dfd3922411d856b98ab6ba5d64c9c1c9f.tar.gz
wic: use truncate utility to create sparse files
Used truncate instead of dd to create wic images for the following reasons: - dd doesn't preserve sparseness - truncate syntax is much more clear - dd requires additional calculations of the image size in blocks - the way dd was used in the code is not always correct. In some cases it was writing one block to the file which makes it not 100% sparse. [YOCTO #9099] Signed-off-by: Ed Bartosh <ed.bartosh@linux.intel.com> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
-rw-r--r--scripts/lib/wic/partition.py20
-rw-r--r--scripts/lib/wic/utils/fs_related.py12
2 files changed, 8 insertions, 24 deletions
diff --git a/scripts/lib/wic/partition.py b/scripts/lib/wic/partition.py
index 227b685137..6d21193902 100644
--- a/scripts/lib/wic/partition.py
+++ b/scripts/lib/wic/partition.py
@@ -220,9 +220,7 @@ class Partition(object):
msger.debug("Added %d extra blocks to %s to get to %d total blocks" % \
(extra_blocks, self.mountpoint, rootfs_size))
- dd_cmd = "dd if=/dev/zero of=%s bs=1024 seek=%d count=0 bs=1k" % \
- (rootfs, rootfs_size)
- exec_cmd(dd_cmd)
+ exec_cmd("truncate %s -s %d" % (rootfs, rootfs_size * 1024))
extra_imagecmd = "-i 8192"
@@ -255,9 +253,7 @@ class Partition(object):
msger.debug("Added %d extra blocks to %s to get to %d total blocks" % \
(extra_blocks, self.mountpoint, rootfs_size))
- dd_cmd = "dd if=/dev/zero of=%s bs=1024 seek=%d count=0 bs=1k" % \
- (rootfs, rootfs_size)
- exec_cmd(dd_cmd)
+ exec_cmd("truncate %s -s %d" % (rootfs, rootfs_size * 1024))
label_str = ""
if self.label:
@@ -320,9 +316,7 @@ class Partition(object):
"""
Prepare an empty ext2/3/4 partition.
"""
- dd_cmd = "dd if=/dev/zero of=%s bs=1k seek=%d count=0" % \
- (rootfs, self.size)
- exec_cmd(dd_cmd)
+ exec_cmd("truncate %s -s %d" % (rootfs, self.size * 1024))
extra_imagecmd = "-i 8192"
@@ -339,9 +333,7 @@ class Partition(object):
"""
Prepare an empty btrfs partition.
"""
- dd_cmd = "dd if=/dev/zero of=%s bs=1k seek=%d count=0" % \
- (rootfs, self.size)
- exec_cmd(dd_cmd)
+ exec_cmd("truncate %s -s %d" % (rootfs, self.size * 1024))
label_str = ""
if self.label:
@@ -402,9 +394,7 @@ class Partition(object):
"""
path = "%s/fs.%s" % (cr_workdir, self.fstype)
- dd_cmd = "dd if=/dev/zero of=%s bs=1k seek=%d count=0" % \
- (path, self.size)
- exec_cmd(dd_cmd)
+ exec_cmd("truncate %s -s %d" % (path, self.size * 1024))
import uuid
label_str = ""
diff --git a/scripts/lib/wic/utils/fs_related.py b/scripts/lib/wic/utils/fs_related.py
index 2e74461a40..2658dcfc20 100644
--- a/scripts/lib/wic/utils/fs_related.py
+++ b/scripts/lib/wic/utils/fs_related.py
@@ -71,14 +71,8 @@ class DiskImage(Disk):
def create(self):
if self.device is not None:
return
-
- blocks = self.size / 1024
- if self.size - blocks * 1024:
- blocks += 1
-
- # create disk image
- dd_cmd = "dd if=/dev/zero of=%s bs=1024 seek=%d count=1" % \
- (self.image_file, blocks)
- exec_cmd(dd_cmd)
+ # create sparse disk image
+ cmd = "truncate %s -s %s" % (self.image_file, self.size)
+ exec_cmd(cmd)
self.device = self.image_file