Fix "resize failed: 1" errors for ext2/ext3/ext4 (#517491).

The following install test case has been failing:
https://fedoraproject.org/wiki/QA:Testcase_Anaconda_autopart_%28shrink%29_install

The problem was with the minSize property in Ext2FS.  We use resize2fs
to get the minSize for ext2/3/4 filesystems, which is good because
resize2fs accounts for additional things an extX volume may need.  The
problem is the value it reports is in blocks.  We have to convert those
blocks to bytes, then to megabytes, then round up to account for any
fractional megabytes.  Use dumpe2fs to get the block size and use
resize2fs as we have been, but modify the calculation of size.

Also the _setTargetSize() method in FS needed a change.  minSize can be
less than or equal to newsize, not just less than.

1 files changed, 25 insertions, 3 deletions

diff --git a/storage/formats/fs.py b/storage/formats/fs.py
index 2f9b6e2e2..b1f6761d2 100644
--- a/storage/formats/fs.py
+++ b/storage/formats/fs.py
@@ -168,7 +168,7 @@ class FS(DeviceFormat):
             self._targetSize = None
             return
 
-        if not self.minSize < newsize < self.maxSize:
+        if not self.minSize <= newsize < self.maxSize:
             raise ValueError("invalid target size request")
 
         self._targetSize = newsize
@@ -860,7 +860,23 @@ class Ext2FS(FS):
             # try once in the beginning to get the minimum size for an
             # existing filesystem.
             size = self._minSize
+            blockSize = None
+
             if self.exists and os.path.exists(self.device):
+                # get block size
+                buf = iutil.execWithCapture(self.infofsProg,
+                                            ["-h", self.device],
+                                            stderr="/dev/tty5")
+                for line in buf.splitlines():
+                    if line.startswith("Block size:"):
+                        blockSize = int(line.split(" ")[-1])
+                        break
+
+                if blockSize is None:
+                    raise FSError("failed to get block size for %s filesystem "
+                                  "on %s" % (self.mountType, self.device))
+
+                # get minimum size according to resize2fs
                 buf = iutil.execWithCapture(self.resizefsProg,
                                             ["-P", self.device],
                                             stderr="/dev/tty5")
@@ -868,9 +884,15 @@ class Ext2FS(FS):
                     if "minimum size of the filesystem:" not in line:
                         continue
 
+                    # line will look like:
+                    # Estimated minimum size of the filesystem: 1148649
+                    #
+                    # NOTE: The minimum size reported is in blocks.  Convert
+                    # to bytes, then megabytes, and finally round up.
                     (text, sep, minSize) = line.partition(": ")
-
-                    size = int(minSize) / 1024.0
+                    size = long(minSize) * blockSize
+                    size = math.ceil(size / 1024.0 / 1024.0)
+                    break
 
                 if size is None:
                     log.warning("failed to get minimum size for %s filesystem "