Merge branch 'wip-prepare'

Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Reviewed-by: Alexandre Marangone <alexandre.marangone@inktank.com>
Tested-by: Tamil Muthamizhan <tamil.muthamizhan@inktank.com>

src/ceph-disk-prepare

@@ -4,6 +4,7 @@ import argparse
 import logging
 import os
 import os.path
+import re
 import subprocess
 import stat
 import sys
@@ -70,28 +71,82 @@ class UnmountError(PrepareError):
     Unmounting filesystem failed
     """
 
+def list_partitions(disk):
+    """
+    Return a list of partitions on the given device
+    """
+    disk = os.path.realpath(disk)
+    assert not is_partition(disk)
+    assert disk.startswith('/dev/')
+    base = disk[5:]
+    ls = []
+    with file('/proc/partitions', 'rb') as f:
+        for line in f.read().split('\n')[2:]:
+            fields = re.split('\s+', line)
+            if len(fields) < 5:
+                continue
+            (_, major, minor, blocks, name) = fields
+            if name != base and name.startswith(base):
+                ls.append('/dev/' + name)
+    return ls
 
 def is_partition(dev):
     """
     Check whether a given device is a partition or a full disk.
     """
-    # resolve symlink(s)
-    max = 10
-    while stat.S_ISLNK(os.lstat(dev).st_mode):
-        dev = os.readlink(dev)
-        max -= 1
-        if max == 0:
-            raise PrepareError('%s is a rats nest of symlinks' % dev)
+    dev = os.path.realpath(dev)
     if not stat.S_ISBLK(os.lstat(dev).st_mode):
         raise PrepareError('not a block device', dev)
 
     # if the device ends in a number, it is a partition (e.g., /dev/sda3)
-
-    # ugh i have no internet.. how do you do a python regex?
-    if dev.endswith('0') or dev.endswith('1') or dev.endswith('2') or dev.endswith('3') or dev.endswith('4') or dev.endswith('4') or dev.endswith('6') or dev.endswith('7') or dev.endswith('8') or dev.endswith('9'):
+    if dev[-1].isdigit():
         return True
     return False
 
+def is_mounted(dev):
+    """
+    Check if the given device is mounted.
+    """
+    dev = os.path.realpath(dev)
+    with file('/proc/mounts') as f:
+        for line in f.read().split('\n'):
+            d = line.split(' ')[0]
+            if os.path.exists(d):
+                d = os.path.realpath(d)
+                if dev == d:
+                    return True
+    return False
+
+def is_held(dev):
+    """
+    Check if a device is held by another device (e.g., a dm-crypt mapping)
+    """
+    assert os.path.exists(dev)
+    dev = os.path.realpath(dev)
+    base = dev[5:]
+    disk = base
+    while disk[-1].isdigit():
+        disk = disk[:-1]
+    dir = '/sys/block/{disk}/{base}/holders'.format(disk=disk, base=base)
+    if not os.path.exists(dir):
+        return []
+    return os.listdir(dir)
+
+def verify_not_in_use(dev):
+    assert os.path.exists(dev)
+    if is_partition(dev):
+        if is_mounted(dev):
+            raise PrepareError('Device is mounted', dev)
+        holders = is_held(dev)
+        if holders:
+            raise PrepareError('Device is in use by a device-mapper mapping (dm-crypt?)' % dev, ','.join(holders))
+    else:
+        for p in list_partitions(dev):
+            if is_mounted(p):
+                raise PrepareError('Device is mounted', p)
+            holders = is_held(p)
+            if holders:
+                raise PrepareError('Device %s is in use by a device-mapper mapping (dm-crypt?)' % p, ','.join(holders))
 
 def write_one_line(parent, name, text):
     """
@@ -804,12 +859,18 @@ def main():
         if not os.path.exists(args.data):
             raise PrepareError('data path does not exist', args.data)
 
-        # FIXME: verify disk/partitions is not in use
+        # in use?
+        dmode = os.stat(args.data).st_mode
+        if stat.S_ISBLK(dmode):
+            verify_not_in_use(args.data)
+
+        if args.journal and os.path.exists(args.journal):
+            jmode = os.stat(args.journal).st_mode
+            if stat.S_ISBLK(jmode):
+                verify_not_in_use(args.journal)
+
         if args.zap_disk is not None:
-            if not os.path.exists(args.data):
-                raise PrepareError('does not exist', args.data)
-            mode = os.stat(args.data).st_mode
-            if stat.S_ISBLK(mode) and not is_partition(args.data):
+            if stat.S_ISBLK(dmode) and not is_partition(args.data):
                 zap(args.data)
             else:
                 raise PrepareError('not full block device; cannot zap', args.data)
@@ -869,7 +930,6 @@ def main():
         journal_size = int(journal_size)
 
         # colocate journal with data?
-        dmode = os.stat(args.data).st_mode
         if stat.S_ISBLK(dmode) and not is_partition(args.data) and args.journal is None and args.journal_file is None:
             log.info('Will colocate journal with data on %s', args.data)
             args.journal = args.data