[parted-devel] [PATCH 10/11] Revert "linux-commit: do not unnecessarily open partition device nodes"

[Phillip Susi]

This reverts commit 2a6936fab4d4499a4b812dd330d3db50549029e0.  The commit
disabled flushing the block buffer caches on the partition nodes to ensure
cache consistency on 2.6 kernels, supposedly because this was no longer
required.  It appears this was incorrect, and the caches DO still need
flushed, otherwise a new fs written to the partition device does not show
up in the disk device cache, causing parted to still identify the old fs.
---
 libparted/arch/linux.c |   25 +++----------------------
 1 file changed, 3 insertions(+), 22 deletions(-)

diff --git a/libparted/arch/linux.c b/libparted/arch/linux.c
index d360400..1e04d48 100644
--- a/libparted/arch/linux.c
+++ b/libparted/arch/linux.c
@@ -703,19 +703,6 @@ _get_linux_version ()
         return kver = KERNEL_VERSION (major, minor, teeny);
 }
 
-static int
-_have_kern26 ()
-{
-        static int have_kern26 = -1;
-        int kver;
-
-        if (have_kern26 != -1)
-                return have_kern26;
-
-        kver = _get_linux_version();
-        return have_kern26 = kver >= KERNEL_VERSION (2,6,0) ? 1 : 0;
-}
-
 #if USE_BLKID
 static void
 get_blkid_topology (LinuxSpecific *arch_specific)
@@ -1567,8 +1554,8 @@ linux_is_busy (PedDevice* dev)
         return 0;
 }
 
-/* we need to flush the master device, and with kernel < 2.6 all the partition
- * devices, because there is no coherency between the caches with old kernels.
+/* we need to flush the master device, and all the partition devices,
+ * because there is no coherency between the caches.
  * We should only flush unmounted partition devices, because:
  *  - there is never a need to flush them (we're not doing IO there)
  *  - flushing a device that is mounted causes unnecessary IO, and can
@@ -1586,10 +1573,6 @@ _flush_cache (PedDevice* dev)
 
         ioctl (arch_specific->fd, BLKFLSBUF);
 
-        /* With linux-2.6.0 and newer, we're done.  */
-        if (_have_kern26())
-                return;
-
         for (i = 1; i < 16; i++) {
                 char*           name;
                 int             fd;
@@ -1654,9 +1637,7 @@ retry:
                 dev->read_only = 0;
         }
 
-        /* With kernels < 2.6 flush cache for cache coherence issues */
-        if (!_have_kern26())
-                _flush_cache (dev);
+        _flush_cache (dev);
 
         return 1;
 }
-- 
1.7.10.4