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Message #00195
[Merge] lp:~blair/cloud-init/cloud-init into lp:cloud-init
Scott Moser has proposed merging lp:~blair/cloud-init/cloud-init into lp:cloud-init.
Commit message:
Support resizing btrfs filesystems.
The existing code has two issues with btrfs:
1) The command to resize a btrfs filesystem uses a path to the mount
point, not the underlying device:
$ btrfs filesystem resize max /dev/vda1
ERROR: unable to resize '/dev/vda1' - Inappropriate ioctl for device
Resize '/dev/vda1' of 'max'
$ btrfs filesystem resize max /
Resize '/' of 'max'
2) The code that is given a path and finds the ID of the device where
the path is mounted doesn't work for btrfs:
Use /proc/$$/mountinfo to find the device where path is mounted.
This is done because with a btrfs filesystem using os.stat(path)
does not return the ID of the device.
Here, / has a device of 18 (decimal).
$ stat /
File: '/'
Size: 234 Blocks: 0 IO Block: 4096 directory
Device: 12h/18d Inode: 256 Links: 1
Access: (0755/drwxr-xr-x) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2013-01-13 07:31:04.358011255 +0000
Modify: 2013-01-13 18:48:25.930011255 +0000
Change: 2013-01-13 18:48:25.930011255 +0000
Birth: -
Find where / is mounted:
$ mount | grep ' / '
/dev/vda1 on / type btrfs (rw,subvol=@,compress=lzo)
And the device ID for /dev/vda1 is not 18:
$ ls -l /dev/vda1
brw-rw---- 1 root disk 253, 1 Jan 13 08:29 /dev/vda1
So use /proc/$$/mountinfo to find the device underlying the input
path.
Requested reviews:
cloud init development team (cloud-init-dev)
For more details, see:
https://code.launchpad.net/~blair/cloud-init/cloud-init/+merge/143347
--
https://code.launchpad.net/~blair/cloud-init/cloud-init/+merge/143347
Your team cloud init development team is requested to review the proposed merge of lp:~blair/cloud-init/cloud-init into lp:cloud-init.
=== modified file 'cloudinit/config/cc_resizefs.py'
--- cloudinit/config/cc_resizefs.py 2012-11-20 06:05:36 +0000
+++ cloudinit/config/cc_resizefs.py 2013-01-15 16:37:28 +0000
@@ -27,9 +27,21 @@
frequency = PER_ALWAYS
+def _resize_btrfs(mount_point, devpth, tmp_devpth, log):
+ return ('btrfs', 'filesystem', 'resize', 'max', mount_point)
+
+def _resize_ext(mount_point, devpth, tmp_devpth, log):
+ nodeify_path(tmp_devpth, resize_what, log)
+ return ('resize2fs', tmp_devpth)
+
+def _resize_xfs(mount_point, devpth, tmp_devpth, log):
+ nodeify_path(tmp_devpth, resize_what, log)
+ return ('xfs_growfs', tmp_devpth)
+
RESIZE_FS_PREFIXES_CMDS = [
- ('ext', 'resize2fs'),
- ('xfs', 'xfs_growfs'),
+ ('btrfs', _resize_btrfs),
+ ('ext', _resize_ext),
+ ('xfs', _resize_xfs),
]
NOBLOCK = "noblock"
@@ -50,19 +62,85 @@
raise
-def get_fs_type(st_dev, path, log):
- try:
- dev_entries = util.find_devs_with(tag='TYPE', oformat='value',
- no_cache=True, path=path)
- if not dev_entries:
- return None
- return dev_entries[0].strip()
- except util.ProcessExecutionError:
- util.logexc(log, ("Failed to get filesystem type"
- " of maj=%s, min=%s for path %s"),
- os.major(st_dev), os.minor(st_dev), path)
- raise
-
+def get_fs_devpth_and_type(path, log):
+ # Use /proc/$$/mountinfo to find the device where path is mounted.
+ # This is done because with a btrfs filesystem using os.stat(path)
+ # does not return the ID of the device.
+ #
+ # Here, / has a device of 18 (decimal).
+ #
+ # $ stat /
+ # File: '/'
+ # Size: 234 Blocks: 0 IO Block: 4096 directory
+ # Device: 12h/18d Inode: 256 Links: 1
+ # Access: (0755/drwxr-xr-x) Uid: ( 0/ root) Gid: ( 0/ root)
+ # Access: 2013-01-13 07:31:04.358011255 +0000
+ # Modify: 2013-01-13 18:48:25.930011255 +0000
+ # Change: 2013-01-13 18:48:25.930011255 +0000
+ # Birth: -
+ #
+ # Find where / is mounted:
+ #
+ # $ mount | grep ' / '
+ # /dev/vda1 on / type btrfs (rw,subvol=@,compress=lzo)
+ #
+ # And the device ID for /dev/vda1 is not 18:
+ #
+ # $ ls -l /dev/vda1
+ # brw-rw---- 1 root disk 253, 1 Jan 13 08:29 /dev/vda1
+ #
+ # So use /proc/$$/mountinfo to find the device underlying the
+ # input path.
+ fs_type = None
+ devpth = None
+ match_mount_elements = None
+ path_elements = [e for e in path.split('/') if e]
+ mountinfo_path = '/proc/%s/mountinfo' % os.getpid()
+ with open(mountinfo_path) as f:
+ for line in f.readlines():
+ # Look for - and use the field two to the right.
+ parts = line.split()
+
+ mount = parts[4]
+ mount_elements = [e for e in mount.split('/') if e]
+
+ # Ignore mounts deeper than the path in question.
+ if len(mount_elements) > len(path_elements):
+ continue
+
+ # Ignore mounts where the common path is not the same.
+ l = min(len(mount_elements), len(path_elements))
+ if mount_elements[0:l] != path_elements[0:l]:
+ continue
+
+ # Ignore mount points higher than an already seen mount
+ # point.
+ if (match_mount_elements is not None and
+ len(match_mount_elements) > len(mount_elements)):
+ continue
+
+ # Find the '-' which terminates a list of optional columns
+ # to find the path to the device and the mount point. See
+ # man 5 proc for the format of this file.
+ try:
+ i = parts.index('-')
+ except ValueError:
+ log.debug("Did not find column named '-' in %s",
+ mountinfo_path)
+ return None
+
+ # Get the path to the device.
+ try:
+ fs_type = parts[i+1]
+ devpth = parts[i+2]
+ except IndexError, e:
+ log.debug("Too few columns in %s after '-' column",
+ mountinfo_path)
+ return None
+
+ match_mount_elements = mount_elements
+
+ return (devpth, fs_type)
def handle(name, cfg, _cloud, log, args):
if len(args) != 0:
@@ -82,7 +160,7 @@
resize_what = "/"
with util.ExtendedTemporaryFile(prefix="cloudinit.resizefs.",
dir=resize_root_d, delete=True) as tfh:
- devpth = tfh.name
+ tmp_devpth = tfh.name
# Delete the file so that mknod will work
# but don't change the file handle to know that its
@@ -91,12 +169,15 @@
# auto deletion
tfh.unlink_now()
- st_dev = nodeify_path(devpth, resize_what, log)
- fs_type = get_fs_type(st_dev, devpth, log)
- if not fs_type:
+ result = get_fs_devpth_and_type(resize_what, log)
+ if not result:
log.warn("Could not determine filesystem type of %s", resize_what)
return
+ (devpth, fs_type) = result
+
+ st_dev = os.stat(devpth).st_rdev
+
resizer = None
fstype_lc = fs_type.lower()
for (pfix, root_cmd) in RESIZE_FS_PREFIXES_CMDS:
@@ -109,8 +190,9 @@
fs_type, resize_what)
return
- log.debug("Resizing %s (%s) using %s", resize_what, fs_type, resizer)
- resize_cmd = [resizer, devpth]
+ resize_cmd = resizer(resize_what, devpth, tmp_devpth, log)
+ log.debug("Resizing %s (%s) using %s", resize_what, fs_type,
+ ' '.join(resize_cmd))
if resize_root == NOBLOCK:
# Fork to a child that will run
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