[Aufs 11/25] aufs sub-dcache

J. R. Okajima
2009-03-09T03:38:21Z

sub-routines or simple wrappers for dentry cache

Signed-off-by: J. R. Okajima <hooanon05@yahoo.co.jp>
---
fs/aufs/dcsub.c | 214 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
fs/aufs/dcsub.h | 43 +++++++++++
2 files changed, 257 insertions(+), 0 deletions(-)
create mode 100644 fs/aufs/dcsub.c
create mode 100644 fs/aufs/dcsub.h

diff --git a/fs/aufs/dcsub.c b/fs/aufs/dcsub.c
new file mode 100644
index 0000000..e4597e4
--- /dev/null
+++ b/fs/aufs/dcsub.c
@@ -0,0 +1,214 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro R. Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+/*
+ * sub-routines for dentry cache
+ */
+
+#include "aufs.h"
+
+static void au_dpage_free(struct au_dpage *dpage)
+{
+ int i;
+ struct dentry **p;
+
+ p = dpage->dentries;
+ for (i = 0; i < dpage->ndentry; i++)
+ dput(*p++);
+ free_page((unsigned long)dpage->dentries);
+}
+
+int au_dpages_init(struct au_dcsub_pages *dpages, gfp_t gfp)
+{
+ int err;
+ void *p;
+
+ err = -ENOMEM;
+ dpages->dpages = kmalloc(sizeof(*dpages->dpages), gfp);
+ if (unlikely(!dpages->dpages))
+ goto out;
+
+ p = (void *)__get_free_page(gfp);
+ if (unlikely(!p))
+ goto out_dpages;
+
+ dpages->dpages[0].ndentry = 0;
+ dpages->dpages[0].dentries = p;
+ dpages->ndpage = 1;
+ return 0; /* success */
+
+ out_dpages:
+ kfree(dpages->dpages);
+ out:
+ return err;
+}
+
+void au_dpages_free(struct au_dcsub_pages *dpages)
+{
+ int i;
+ struct au_dpage *p;
+
+ p = dpages->dpages;
+ for (i = 0; i < dpages->ndpage; i++)
+ au_dpage_free(p++);
+ kfree(dpages->dpages);
+}
+
+static int au_dpages_append(struct au_dcsub_pages *dpages,
+ struct dentry *dentry, gfp_t gfp)
+{
+ int err, sz;
+ struct au_dpage *dpage;
+ void *p;
+
+ dpage = dpages->dpages + dpages->ndpage - 1;
+ sz = PAGE_SIZE / sizeof(dentry);
+ if (unlikely(dpage->ndentry >= sz)) {
+ AuLabel(new dpage);
+ err = -ENOMEM;
+ sz = dpages->ndpage * sizeof(*dpages->dpages);
+ p = au_kzrealloc(dpages->dpages, sz,
+ sz + sizeof(*dpages->dpages), gfp);
+ if (unlikely(!p))
+ goto out;
+
+ dpages->dpages = p;
+ dpage = dpages->dpages + dpages->ndpage;
+ p = (void *)__get_free_page(gfp);
+ if (unlikely(!p))
+ goto out;
+
+ dpage->ndentry = 0;
+ dpage->dentries = p;
+ dpages->ndpage++;
+ }
+
+ dpage->dentries[dpage->ndentry++] = dget(dentry);
+ return 0; /* success */
+
+ out:
+ return err;
+}
+
+int au_dcsub_pages(struct au_dcsub_pages *dpages, struct dentry *root,
+ au_dpages_test test, void *arg)
+{
+ int err;
+ struct dentry *this_parent = root;
+ struct list_head *next;
+ struct super_block *sb = root->d_sb;
+
+ err = 0;
+ spin_lock(&dcache_lock);
+ repeat:
+ next = this_parent->d_subdirs.next;
+ resume:
+ if (this_parent->d_sb == sb
+ && !IS_ROOT(this_parent)
+ && atomic_read(&this_parent->d_count)
+ && this_parent->d_inode
+ && (!test || test(this_parent, arg))) {
+ err = au_dpages_append(dpages, this_parent, GFP_ATOMIC);
+ if (unlikely(err))
+ goto out;
+ }
+
+ while (next != &this_parent->d_subdirs) {
+ struct list_head *tmp = next;
+ struct dentry *dentry = list_entry(tmp, struct dentry,
+ d_u.d_child);
+ next = tmp->next;
+ if (/*d_unhashed(dentry) || */!dentry->d_inode)
+ continue;
+ if (!list_empty(&dentry->d_subdirs)) {
+ this_parent = dentry;
+ goto repeat;
+ }
+ if (dentry->d_sb == sb
+ && atomic_read(&dentry->d_count)
+ && (!test || test(dentry, arg))) {
+ err = au_dpages_append(dpages, dentry, GFP_ATOMIC);
+ if (unlikely(err))
+ goto out;
+ }
+ }
+
+ if (this_parent != root) {
+ next = this_parent->d_u.d_child.next;
+ this_parent = this_parent->d_parent; /* dcache_lock is locked */
+ goto resume;
+ }
+ out:
+ spin_unlock(&dcache_lock);
+ return err;
+}
+
+int au_dcsub_pages_rev(struct au_dcsub_pages *dpages, struct dentry *dentry,
+ int do_include, au_dpages_test test, void *arg)
+{
+ int err;
+
+ err = 0;
+ spin_lock(&dcache_lock);
+ if (do_include && (!test || test(dentry, arg))) {
+ err = au_dpages_append(dpages, dentry, GFP_ATOMIC);
+ if (unlikely(err))
+ goto out;
+ }
+ while (!IS_ROOT(dentry)) {
+ dentry = dentry->d_parent; /* dcache_lock is locked */
+ if (!test || test(dentry, arg)) {
+ err = au_dpages_append(dpages, dentry, GFP_ATOMIC);
+ if (unlikely(err))
+ break;
+ }
+ }
+
+ out:
+ spin_unlock(&dcache_lock);
+
+ return err;
+}
+
+struct dentry *au_test_subdir(struct dentry *d1, struct dentry *d2)
+{
+ struct dentry *trap, **dentries;
+ int err, i, j;
+ struct au_dcsub_pages dpages;
+ struct au_dpage *dpage;
+
+ trap = ERR_PTR(-ENOMEM);
+ err = au_dpages_init(&dpages, GFP_NOFS);
+ if (unlikely(err))
+ goto out;
+ err = au_dcsub_pages_rev(&dpages, d1, /*do_include*/1, NULL, NULL);
+ if (unlikely(err))
+ goto out_dpages;
+
+ trap = d1;
+ for (i = 0; !err && i < dpages.ndpage; i++) {
+ dpage = dpages.dpages + i;
+ dentries = dpage->dentries;
+ for (j = 0; !err && j < dpage->ndentry; j++) {
+ struct dentry *d;
+
+ d = dentries[j];
+ err = (d == d2);
+ if (!err)
+ trap = d;
+ }
+ }
+ if (!err)
+ trap = NULL;
+
+ out_dpages:
+ au_dpages_free(&dpages);
+ out:
+ return trap;
+}
diff --git a/fs/aufs/dcsub.h b/fs/aufs/dcsub.h
new file mode 100644
index 0000000..89a7745
--- /dev/null
+++ b/fs/aufs/dcsub.h
@@ -0,0 +1,43 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro R. Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+/*
+ * sub-routines for dentry cache
+ */
+
+#ifndef __AUFS_DCSUB_H__
+#define __AUFS_DCSUB_H__
+
+#ifdef __KERNEL__
+
+#include <linux/dcache.h>
+
+struct au_dpage {
+ int ndentry;
+ struct dentry **dentries;
+};
+
+struct au_dcsub_pages {
+ int ndpage;
+ struct au_dpage *dpages;
+};
+
+/* ---------------------------------------------------------------------- */
+
+int au_dpages_init(struct au_dcsub_pages *dpages, gfp_t gfp);
+void au_dpages_free(struct au_dcsub_pages *dpages);
+typedef int (*au_dpages_test)(struct dentry *dentry, void *arg);
+int au_dcsub_pages(struct au_dcsub_pages *dpages, struct dentry *root,
+ au_dpages_test test, void *arg);
+int au_dcsub_pages_rev(struct au_dcsub_pages *dpages, struct dentry *dentry,
+ int do_include, au_dpages_test test, void *arg);
+struct dentry *au_test_subdir(struct dentry *d1, struct dentry *d2);
+
+#endif /* __KERNEL__ */
+#endif /* __AUFS_DCSUB_H__ */
--
1.6.1.284.g5dc13