use by-id disk names in db and consequent btrfs commands rockstor#1320

Initial conversion of disk name entries in db from 'sda' type to
those created by udev in the /dev/disk/by-id directory. Also
involves changing hard coded paths in low level btrfs functions.

src/rockstor/fs/btrfs.py

@@ -57,7 +57,7 @@ def add_pool(pool, disks):
     """
     pool is a btrfs filesystem.
     """
-    disks_fp = ['/dev/' + d for d in disks]
+    disks_fp = ['/dev/disk/by-id/' + d for d in disks]
     cmd = [MKFS_BTRFS, '-f', '-d', pool.raid, '-m', pool.raid, '-L',
            pool.name, ]
     cmd.extend(disks_fp)
@@ -67,7 +67,8 @@ def add_pool(pool, disks):
 
 
 def get_pool_info(disk):
-    cmd = [BTRFS, 'fi', 'show', '/dev/%s' % disk]
+    # cmd = [BTRFS, 'fi', 'show', '/dev/%s' % disk]
+    cmd = [BTRFS, 'fi', 'show', '/dev/disk/by-id/%s' % disk]
     o, e, rc = run_command(cmd)
     pool_info = {'disks': [],}
     for l in o:
@@ -148,7 +149,7 @@ def mount_root(pool):
         raise Exception('Cannot mount Pool(%s) as it has no disks in it.' % pool.name)
     last_device = pool.disk_set.last()
     for device in pool.disk_set.all():
-        mnt_device = ('/dev/%s' % device.name)
+        mnt_device = ('/dev/disk/by-id/%s' % device.name)
         if (os.path.exists(mnt_device)):
             mnt_cmd = [MOUNT, mnt_device, root_pool_mnt, ]
             if (len(mnt_options) > 0):
@@ -232,15 +233,15 @@ def mount_share(share, mnt_pt):
     if (is_mounted(mnt_pt)):
         return
     mount_root(share.pool)
-    pool_device = ('/dev/%s' % share.pool.disk_set.first().name)
+    pool_device = ('/dev/disk/by-id/%s' % share.pool.disk_set.first().name)
     subvol_str = 'subvol=%s' % share.subvol_name
     create_tmp_dir(mnt_pt)
     mnt_cmd = [MOUNT, '-t', 'btrfs', '-o', subvol_str, pool_device, mnt_pt]
     return run_command(mnt_cmd)
 
 
 def mount_snap(share, snap_name, snap_mnt=None):
-    pool_device = ('/dev/%s' % share.pool.disk_set.first().name)
+    pool_device = ('/dev/disk/by-id/%s' % share.pool.disk_set.first().name)
     share_path = ('%s%s' % (DEFAULT_MNT_DIR, share.name))
     rel_snap_path = ('.snapshots/%s/%s' % (share.name, snap_name))
     snap_path = ('%s%s/%s' %
@@ -782,17 +783,20 @@ def device_scan():
 
 def btrfs_uuid(disk):
     """return uuid of a btrfs filesystem"""
-    o, e, rc = run_command([BTRFS, 'filesystem', 'show', '/dev/%s' % disk])
+    o, e, rc = run_command(
+        [BTRFS, 'filesystem', 'show', '/dev/disk/by-id/%s' % disk])
     return o[0].split()[3]
 
 
 def btrfs_label(disk):
-    o, e, rc = run_command([BTRFS, 'filesystem', 'label', '/dev/%s' % disk])
+    o, e, rc = run_command(
+        [BTRFS, 'filesystem', 'label', '/dev/disk/by-id/%s' % disk])
     return o[0]
 
 
 def btrfs_importable(disk):
-    o, e, rc = run_command([BTRFS, 'check', '/dev/%s' % disk], throw=False)
+    o, e, rc = run_command([BTRFS, 'check', '/dev/disk/by-id/%s' % disk],
+                           throw=False)
     if (rc == 0):
         return True
     return False
@@ -1100,13 +1104,13 @@ def scan_disks(min_size):
 
 def wipe_disk(disk):
     # todo candidate for move to system/osi as not btrfs related
-    disk = ('/dev/%s' % disk)
+    disk = ('/dev/disk/by-id/%s' % disk)
     return run_command([WIPEFS, '-a', disk])
 
 
 def blink_disk(disk, total_exec, read, sleep):
     # todo candidate for move to system/osi as not btrfs related
-    DD_CMD = [DD, 'if=/dev/%s' % disk, 'of=/dev/null', 'bs=512',
+    DD_CMD = [DD, 'if=/dev/disk/by-id/%s' % disk, 'of=/dev/null', 'bs=512',
               'conv=noerror']
     p = subprocess.Popen(DD_CMD, shell=False, stdout=subprocess.PIPE,
                          stderr=subprocess.PIPE)

src/rockstor/storageadmin/views/disk.py

@@ -30,7 +30,8 @@
 from django.conf import settings
 import rest_framework_custom as rfc
 from system import smart
-from system.osi import set_disk_spindown, enter_standby
+from system.osi import set_disk_spindown, enter_standby, get_dev_byid_name, \
+    get_devname
 from copy import deepcopy
 import uuid
 import json
@@ -74,10 +75,14 @@ def _update_disk_state():
             # N.B. do not optimize by re-using uuid index as this could lead
             # to a non refreshed webui acting upon an entry that is different
             # from that shown to the user.
+            #todo - re-address in light of new by-id names which are much longer
+            #todo - so will cause collision, and hence false positive on missing
+            #todo - by having 32 char long name flag, ie add 'missing-' to this.
             do.name = str(uuid.uuid4()).replace('-', '')  # 32 chars long
             # Delete duplicate or fake by serial number db disk entries.
             # It makes no sense to save fake serial number drives between scans
             # as on each scan the serial number is re-generated anyway.
+            # N.B. serial number len 48 assumed fake as uuid4 from scan_disks.
             if (do.serial in serial_numbers_seen) or (len(do.serial) == 48):
                 logger.info('Deleting duplicate or fake (by serial) Disk db '
                             'entry. Serial = %s' % do.serial)
@@ -100,15 +105,21 @@ def _update_disk_state():
         for d in disks:
             # start with an empty disk object
             dob = None
+            # Convert our transient but just scanned so current sda type name
+            # to a more useful by-id type name as found in /dev/disk/by-id
+            byid_disk_name = get_dev_byid_name(d.name, True)
+            logger.debug('Converting %s to by-id of %s' % (d.name, byid_disk_name))
             # If the db has an entry with this disk's serial number then
             # use this db entry and update the device name from our recent scan.
             if (Disk.objects.filter(serial=d.serial).exists()):
                 dob = Disk.objects.get(serial=d.serial)
-                dob.name = d.name
+                #dob.name = d.name
+                dob.name = byid_disk_name
             else:
                 # We have an assumed new disk entry as no serial match in db.
                 # Build a new entry for this disk.
-                dob = Disk(name=d.name, serial=d.serial)
+                #dob = Disk(name=d.name, serial=d.serial)
+                dob = Disk(name=byid_disk_name, serial=d.serial)
             # Update the db disk object (existing or new) with our scanned info
             dob.size = d.size
             dob.parted = d.parted
@@ -212,6 +223,11 @@ def _update_disk_state():
             # find all the not offline db entries
             if (not do.offline):
                 # We have an attached disk db entry
+                # Since our Disk.name model now uses by-id we need to convert
+                # this back to a /dev/vd*, /dev/md*, /dev/mmcblk* type name
+                # as a cheap evaluation of it's type ie virtio, md, or sdcard.
+                bus_based_devname = get_devname('/dev/disk/by-id/%s' % do.name)
+                logger.debug('bus-type-name for %s = %s' % (do.name, bus_based_devname))
                 if (re.match('vd|md|mmcblk', do.name) is not None):
                     # Virtio disks (named vd*), md devices (named md*), and
                     # an sdcard reader that provides devs named mmcblk* have
@@ -222,8 +238,10 @@ def _update_disk_state():
                 # try to establish smart availability and status and update db
                 try:
                     # for non ata/sata drives
+                    #do.smart_available, do.smart_enabled = smart.available(
+                    #    do.name, do.smart_options)
                     do.smart_available, do.smart_enabled = smart.available(
-                        do.name, do.smart_options)
+                        bus_based_devname, do.smart_options)
                 except Exception, e:
                     logger.exception(e)
                     do.smart_available = do.smart_enabled = False