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authorPoornima G <pgurusid@redhat.com>2016-08-23 18:15:22 +0530
committerRaghavendra G <rgowdapp@redhat.com>2016-08-30 23:08:54 -0700
commit065a27948c4e0651f5bdac1703939adf34e5380e (patch)
tree8e563eb9e75337f9e36852e7ea2a95be27e359aa /libglusterfs/src/glusterfs.h
parent8f053f9d7270f1c6d50c0b3ab5d020503ceeb31a (diff)
dht, md-cache, upcall: Add invalidation of IATT when the layout changes
Issue: dht_layout is built as a part of lookup only. The layout can be modified by rebalance process. Since every IO fop is preceded by a lookup, there are very less issues of stale layout. But with enhancements of aggressive caching of stats in md-cache, the lookup will reduce and expose the stale layout issue often. Solution: Since stale layout is already an issue on dht, there is already a plan to fix this at the dht layer, but this fix is not currently planned for any release. Until this fix comes out, we can have a workaround where, the upcall will send a notification to md-cache when a layout xattr is changed. As a part of layout change notification the existing cache is invalidated and the next lookup will fetch the latest layout. This is not a foolproof solution as the window between the layout change and the next lookup(after invalidation of stat), where there will be stale layout. But until the final fix comes in, this reduces the stale layout window. Change-Id: Iacf871a38b35880c1fc0bc68fe7ce291265e71d4 BUG: 1369638 Signed-off-by: Poornima G <pgurusid@redhat.com> Reviewed-on: http://review.gluster.org/15300 NetBSD-regression: NetBSD Build System <jenkins@build.gluster.org> CentOS-regression: Gluster Build System <jenkins@build.gluster.org> Smoke: Gluster Build System <jenkins@build.gluster.org> Reviewed-by: Raghavendra G <rgowdapp@redhat.com>
Diffstat (limited to 'libglusterfs/src/glusterfs.h')
-rw-r--r--libglusterfs/src/glusterfs.h4
1 files changed, 4 insertions, 0 deletions
diff --git a/libglusterfs/src/glusterfs.h b/libglusterfs/src/glusterfs.h
index 8d387bafb3b..5777974676f 100644
--- a/libglusterfs/src/glusterfs.h
+++ b/libglusterfs/src/glusterfs.h
@@ -284,6 +284,10 @@
#define GF_LK_ADVISORY 0
#define GF_LK_MANDATORY 1
+/* md-cache keys */
+#define MDC_INVALIDATE_IATT "mdc.invalidate.iatt"
+#define MDC_INVALIDATE_XATT "mdc.invalidate.xatt"
+
const char *fop_enum_to_pri_string (glusterfs_fop_t fop);
const char *fop_enum_to_string (glusterfs_fop_t fop);