On Fri, 2009-03-13 at 18:09 -1000, David Cantrell wrote:
> The _getExistingSize() method in class FS will using the filesystem
> info/dump utility to figure out the size of the filesystem. Each
> filesystem must define _infofs, _defaultInfoOptions, and
> _existingSizeFields.
Looks okay to me. This is kind of scary stuff, but I think that's just
how it is when you have to parse output like this.
Dave
> ---
> storage/formats/fs.py | 93 ++++++++++++++++++++++++++++++++++++++++++++++++-
> 1 files changed, 92 insertions(+), 1 deletions(-)
>
> diff --git a/storage/formats/fs.py b/storage/formats/fs.py
> index f467852..5fbe62d 100644
> --- a/storage/formats/fs.py
> +++ b/storage/formats/fs.py
> @@ -18,6 +18,7 @@
> # Red Hat, Inc.
> #
> # Red Hat Author(s): Dave Lehman <dlehman@xxxxxxxxxx>
> +# David Cantrell <dcantrell@xxxxxxxxxx>
> #
>
> """ Filesystem classes for use by anaconda.
> @@ -120,12 +121,15 @@ class FS(DeviceFormat):
> _labelfs = "" # labeling utility
> _fsck = "" # fs check utility
> _migratefs = "" # fs migration utility
> + _infofs = "" # fs info utility
> _defaultFormatOptions = [] # default options passed to mkfs
> _defaultMountOptions = ["defaults"] # default options passed to mount
> _defaultLabelOptions = []
> _defaultCheckOptions = []
> _defaultMigrateOptions = []
> + _defaultInfoOptions = []
> _migrationTarget = None
> + _existingSizeFields = []
> lostAndFoundContext = None
>
> def __init__(self, *args, **kwargs):
> @@ -150,8 +154,12 @@ class FS(DeviceFormat):
> self.mountpoint = kwargs.get("mountpoint")
> self.mountopts = kwargs.get("mountopts")
> self.label = kwargs.get("label")
> +
> # filesystem size does not necessarily equal device size
> self._size = kwargs.get("size")
> + if self.exists:
> + self._size = self._getExistingSize()
> +
> self._targetSize = self._size
> self._mountpoint = None # the current mountpoint when mounted
>
> @@ -187,6 +195,83 @@ class FS(DeviceFormat):
> size = property(_getSize, doc="This filesystem's size, accounting "
> "for pending changes")
>
> + def _getExistingSize(self):
> + """ Determine the size of this filesystem. Filesystem must
> + exist. Each filesystem varies, but the general procedure
> + is to run the filesystem dump or info utility and read
> + the block size and number of blocks for the filesystem
> + and compute megabytes from that.
> +
> + The loop that reads the output from the infofsProg is meant
> + to be simple, but take in to account variations in output.
> + The general procedure:
> + 1) Capture output from infofsProg.
> + 2) Iterate over each line of the output:
> + a) Trim leading and trailing whitespace.
> + b) Break line into fields split on ' '
> + c) If line begins with any of the strings in
> + _existingSizeFields, start at the end of
> + fields and take the first one that converts
> + to a long. Store this in the values list.
> + d) Repeat until the values list length equals
> + the _existingSizeFields length.
> + 3) If the length of the values list equals the length
> + of _existingSizeFields, compute the size of this
> + filesystem by multiplying all of the values together
> + to get bytes, then convert to megabytes. Return
> + this value.
> + 4) If we were unable to capture all fields, return 0.
> +
> + The caller should catch exceptions from this method. Any
> + exception raised indicates a need to change the fields we
> + are looking for, the command to run and arguments, or
> + something else. If you catch an exception from this method,
> + assume the filesystem cannot be resized.
> + """
> + size = 0
> +
> + if self.exists:
> + values = []
> + argv = self._defaultInfoOptions + [ self.device ]
> +
> + buf = iutil.execWithCapture(self.infofsProg, argv,
> + stderr="/dev/tty5")
> +
> + for line in buf.splitlines():
> + found = False
> +
> + line = line.strip()
> + tmp = line.split(' ')
> + tmp.reverse()
> +
> + for field in self._existingSizeFields:
> + if line.startswith(field):
> + for subfield in tmp:
> + try:
> + values.append(long(subfield))
> + found = True
> + break
> + except ValueError:
> + continue
> +
> + if found:
> + break
> +
> + if len(values) == len(self._existingSizeFields):
> + break
> +
> + if len(values) != len(self._existingSizeFields):
> + return 0
> +
> + size = 1
> + for value in values:
> + size *= value
> +
> + # report current size as megabytes
> + size = size / 1024.0 / 1024.0
> +
> + return size
> +
> @property
> def currentSize(self):
> """ The filesystem's current actual size. """
> @@ -547,13 +632,19 @@ class FS(DeviceFormat):
> return self._migratefs
>
> @property
> + def infofsProg(self):
> + """ Program used to get information about this filesyste. """
> + return self._infofs
> +
> + @property
> def migrationTarget(self):
> return self._migrationTarget
>
> @property
> def utilsAvailable(self):
> # we aren't checking for fsck because we shouldn't need it
> - for prog in [self.mkfsProg, self.resizefsProg, self.labelfsProg]:
> + for prog in [self.mkfsProg, self.resizefsProg, self.labelfsProg,
> + self.infofsProg]:
> if not prog:
> continue
>
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