ceph: enable/disable dentry complete flags via mount option
Enable/disable use of the dentry dir 'complete' flag via a mount option.
This lets the admin control whether ceph uses the dcache to satisfy
negative lookups or readdir when it has the entire directory contents in
its cache.
This is purely a performance optimization; correctness is guaranteed
whether it is enabled or not.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sage Weil <sage@newdream.net>
diff --git a/fs/ceph/super.c b/fs/ceph/super.c
index ec74313..9c62fe0 100644
--- a/fs/ceph/super.c
+++ b/fs/ceph/super.c
@@ -131,6 +131,8 @@
Opt_rbytes,
Opt_norbytes,
Opt_noasyncreaddir,
+ Opt_dcache,
+ Opt_nodcache,
Opt_ino32,
};
@@ -152,6 +154,8 @@
{Opt_rbytes, "rbytes"},
{Opt_norbytes, "norbytes"},
{Opt_noasyncreaddir, "noasyncreaddir"},
+ {Opt_dcache, "dcache"},
+ {Opt_nodcache, "nodcache"},
{Opt_ino32, "ino32"},
{-1, NULL}
};
@@ -231,6 +235,12 @@
case Opt_noasyncreaddir:
fsopt->flags |= CEPH_MOUNT_OPT_NOASYNCREADDIR;
break;
+ case Opt_dcache:
+ fsopt->flags |= CEPH_MOUNT_OPT_DCACHE;
+ break;
+ case Opt_nodcache:
+ fsopt->flags &= ~CEPH_MOUNT_OPT_DCACHE;
+ break;
case Opt_ino32:
fsopt->flags |= CEPH_MOUNT_OPT_INO32;
break;
@@ -377,6 +387,10 @@
seq_puts(m, ",norbytes");
if (fsopt->flags & CEPH_MOUNT_OPT_NOASYNCREADDIR)
seq_puts(m, ",noasyncreaddir");
+ if (fsopt->flags & CEPH_MOUNT_OPT_DCACHE)
+ seq_puts(m, ",dcache");
+ else
+ seq_puts(m, ",nodcache");
if (fsopt->wsize)
seq_printf(m, ",wsize=%d", fsopt->wsize);