bitbake: monitordisk.py: disable the inode checking for some fs

There is an error when use disk monitor on btrfs:
WARNING: The free inode of rootfs is running low (0.000K left)
ERROR: Immediately abort since the disk space monitor action is "ABORT"!

This is beucase some fs formats' statvfs.f_files (inodes) is zero, thus
the statvfs.f_favail (free inodes) is zero, too, this a feature of the
fs, we disable the inode checking for such a fs.

[YOCTO #3609]

(Bitbake rev: 3eeba5c769b7dcb06f4868d6dbc15f05864e97fe)

Signed-off-by: Robert Yang <liezhi.yang@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

bitbake/lib/bb/monitordisk.py

@@ -128,7 +128,7 @@ def getDiskData(BBDirs, configuration):
         if not os.path.exists(path):
             bb.utils.mkdirhier(path)
         mountedDev = getMountedDev(path)
-        devDict[mountedDev] = action, path, minSpace, minInode
+        devDict[mountedDev] = [action, path, minSpace, minInode]
 
     return devDict
 
@@ -231,6 +231,13 @@ class diskMonitor:
                 freeInode = st.f_favail
 
                 if self.devDict[dev][3] and freeInode < self.devDict[dev][3]:
+                    # Some fs formats' (e.g., btrfs) statvfs.f_files (inodes) is
+                    # zero, this is a feature of the fs, we disable the inode
+                    # checking for such a fs.
+                    if st.f_files == 0:
+                        logger.warn("Inode check for %s is unavaliable, remove it from disk monitor" % dev)
+                        self.devDict[dev][3] = None
+                        continue
                     # Always show warning, the self.checked would always be False if the action is WARN
                     if self.preFreeI[dev] == 0 or self.preFreeI[dev] - freeInode > self.inodeInterval and not self.checked[dev]:
                         logger.warn("The free inode of %s is running low (%.3fK left)" % (dev, freeInode / 1024.0))