lib/deploy: Ignore FIFREEZE/FITHAW errors when already in state

If the filesystem is already frozen, FIFREEZE returns EBUSY, and if the
filesystem is already thawed, FITHAW returns EINVAL. It's very unlikely
these issues would arise on a real ostree system since the sysroot would
be locked during the freeze/thaw cycle.

However, when multiple fake sysroots are used during the test suite (run
as root), the tests could race to run the freeze/thaw cycle without
locking. Furthermore, there's no reason why an independent process might
be trying to freeze the filesystem while ostree was deploying. Ignore
but warn for these errors since there's not much ostree can do about it,
anyways.

Closes: #1260
Approved by: cgwalters

diff --git a/src/libostree/ostree-sysroot-deploy.c b/src/libostree/ostree-sysroot-deploy.c
index 920c0eb47e701ecb02a1a77aca402d759a62bbc3..4b2f3707ebc2031e11bcb068bc623cda21710026 100644 (file)
--- a/src/libostree/ostree-sysroot-deploy.c
+++ b/src/libostree/ostree-sysroot-deploy.c
@@ -1332,11 +1332,15 @@ fsfreeze_thaw_cycle (OstreeSysroot *self,
       /* Do a freeze/thaw cycle; TODO add a FIFREEZETHAW ioctl */
       if (ioctl (rootfs_dfd, FIFREEZE, 0) != 0)
         {
-          /* Not supported, or we're running in the unit tests (as non-root)?
+          /* Not supported, we're running in the unit tests (as non-root), or
+           * the filesystem is already frozen (EBUSY).
            * OK, let's just do a syncfs.
            */
-          if (G_IN_SET (errno, EOPNOTSUPP, EPERM))
+          if (G_IN_SET (errno, EOPNOTSUPP, EPERM, EBUSY))
             {
+              /* Warn if the filesystem was already frozen */
+              if (errno == EBUSY)
+                g_debug ("Filesystem already frozen, falling back to syncfs");
               if (TEMP_FAILURE_RETRY (syncfs (rootfs_dfd)) != 0)
                 return glnx_throw_errno_prefix (error, "syncfs");
               /* Write the completion, and return */
@@ -1349,7 +1353,13 @@ fsfreeze_thaw_cycle (OstreeSysroot *self,
         }
       /* And finally thaw, then signal our completion to the watchdog */
       if (TEMP_FAILURE_RETRY (ioctl (rootfs_dfd, FITHAW, 0)) != 0)
-        return glnx_throw_errno_prefix (error, "ioctl(FITHAW)");
+        {
+          /* Warn but don't error if the filesystem was already thawed */
+          if (errno == EINVAL)
+            g_debug ("Filesystem already thawed");
+          else
+            return glnx_throw_errno_prefix (error, "ioctl(FITHAW)");
+        }
       if (write (sock_parent, &c, sizeof (c)) != sizeof (c))
         return glnx_throw_errno_prefix (error, "write(watchdog FITHAW complete)");
     }