add snapfs to cvs

[fs/lustre-release.git] / lustre / snapfs / dcache.c

diff --git a/lustre/snapfs/dcache.c b/lustre/snapfs/dcache.c
new file mode 100644 (file)
index 0000000..88ce4bb
--- /dev/null
+++ b/lustre/snapfs/dcache.c
@@ -0,0 +1,56 @@
+/*
+ * Directory operations for SnapFS filesystem
+ */
+
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/fs.h>
+#include <linux/stat.h>
+#include <linux/errno.h>
+#include <linux/locks.h>
+#include <asm/segment.h>
+#include <asm/uaccess.h>
+#include <linux/string.h>
+
+#include <linux/filter.h>
+#include <linux/snapfs.h>
+#include <linux/snapsupport.h>
+
+/* called when a cache lookup succeeds */
+
+/* XXX PJB: the intent here is to make sure that inodes which are
+   currently primary inodes under .snap directories are dropped when
+   they are COWED.  It seems hard to me to get semantics that are equally
+   good as for mounted snap_clone file systems, but we should try to get
+   close 
+*/
+static int currentfs_dentry_revalidate(struct dentry *de, int flag)
+{
+//     struct inode *inode = de->d_inode;
+       ENTRY;
+
+       /* unless an ancestor is a .snap directory there is nothing to do */
+#if 0
+       if ( !currentfs_is_under_dotsnap(dentry) ) {
+               EXIT;
+               return 1;
+       }
+       /* XXX PJB get this to work guys! */
+       if ( de->d_parent == "dotsnap inode" && 
+            inode_is_newer_than(find_time_by_name(de->d_parent->d_name.name))){
+               1. drop this dentry 
+               2. make sure the VFS does a new lookup
+                3. probably all you need to do is 
+               return 0;
+       }
+#else 
+       return 1;
+#endif
+}
+
+struct dentry_operations currentfs_dentry_ops = 
+{
+       d_revalidate: currentfs_dentry_revalidate
+};
+