[PATCH] v9fs: simplify fid mapping
v9fs has been plagued by an over-complicated approach trying to map Linux
dentry semantics to Plan 9 fid semantics. Our previous approach called for
aggressive flushing of the dcache resulting in several problems (including
wierd cwd behavior when running /bin/pwd).
This patch dramatically simplifies our handling of this fid management. Fids
will not be clunked as promptly, but the new approach is more functionally
correct. We now clunk un-open fids only when their dentry ref_count reaches 0
(and d_delete is called).
Another simplification is we no longer seek to match fids to the process-id or
uid of the action initiator. The uid-matching will need to be revisited when
we fix the security model.
Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/fs/9p/vfs_dentry.c b/fs/9p/vfs_dentry.c
index 2dd806d..12c9cc9 100644
--- a/fs/9p/vfs_dentry.c
+++ b/fs/9p/vfs_dentry.c
@@ -43,47 +43,18 @@
#include "fid.h"
/**
- * v9fs_dentry_validate - VFS dcache hook to validate cache
- * @dentry: dentry that is being validated
- * @nd: path data
+ * v9fs_dentry_delete - called when dentry refcount equals 0
+ * @dentry: dentry in question
*
- * dcache really shouldn't be used for 9P2000 as at all due to
- * potential attached semantics to directory traversal (walk).
- *
- * FUTURE: look into how to use dcache to allow multi-stage
- * walks in Plan 9 & potential for better dcache operation which
- * would remain valid for Plan 9 semantics. Older versions
- * had validation via stat for those interested. However, since
- * stat has the same approximate overhead as walk there really
- * is no difference. The only improvement would be from a
- * time-decay cache like NFS has and that undermines the
- * synchronous nature of 9P2000.
+ * By returning 1 here we should remove cacheing of unused
+ * dentry components.
*
*/
-static int v9fs_dentry_validate(struct dentry *dentry, struct nameidata *nd)
+int v9fs_dentry_delete(struct dentry *dentry)
{
- struct dentry *dc = current->fs->pwd;
-
- dprintk(DEBUG_VFS, "dentry: %s (%p)\n", dentry->d_iname, dentry);
- if (v9fs_fid_lookup(dentry)) {
- dprintk(DEBUG_VFS, "VALID\n");
- return 1;
- }
-
- while (dc != NULL) {
- if (dc == dentry) {
- dprintk(DEBUG_VFS, "VALID\n");
- return 1;
- }
- if (dc == dc->d_parent)
- break;
-
- dc = dc->d_parent;
- }
-
- dprintk(DEBUG_VFS, "INVALID\n");
- return 0;
+ dprintk(DEBUG_VFS, " dentry: %s (%p)\n", dentry->d_iname, dentry);
+ return 1;
}
/**
@@ -118,6 +89,6 @@
}
struct dentry_operations v9fs_dentry_operations = {
- .d_revalidate = v9fs_dentry_validate,
+ .d_delete = v9fs_dentry_delete,
.d_release = v9fs_dentry_release,
};