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authorAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-08-05 17:04:01 -0300
committerAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-08-05 17:04:01 -0300
commit57f0f512b273f60d52568b8c6b77e17f5636edc0 (patch)
tree5e910f0e82173f4ef4f51111366a3f1299037a7b /fs/aufs/dcsub.c
Initial import
Diffstat (limited to 'fs/aufs/dcsub.c')
-rw-r--r--fs/aufs/dcsub.c224
1 files changed, 224 insertions, 0 deletions
diff --git a/fs/aufs/dcsub.c b/fs/aufs/dcsub.c
new file mode 100644
index 000000000..910a2e870
--- /dev/null
+++ b/fs/aufs/dcsub.c
@@ -0,0 +1,224 @@
+/*
+ * Copyright (C) 2005-2015 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.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/*
+ * 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++;
+ }
+
+ AuDebugOn(au_dcount(dentry) <= 0);
+ dpage->dentries[dpage->ndentry++] = dget_dlock(dentry);
+ return 0; /* success */
+
+out:
+ return err;
+}
+
+/* todo: BAD approach */
+/* copied from linux/fs/dcache.c */
+enum d_walk_ret {
+ D_WALK_CONTINUE,
+ D_WALK_QUIT,
+ D_WALK_NORETRY,
+ D_WALK_SKIP,
+};
+
+extern void d_walk(struct dentry *parent, void *data,
+ enum d_walk_ret (*enter)(void *, struct dentry *),
+ void (*finish)(void *));
+
+struct ac_dpages_arg {
+ int err;
+ struct au_dcsub_pages *dpages;
+ struct super_block *sb;
+ au_dpages_test test;
+ void *arg;
+};
+
+static enum d_walk_ret au_call_dpages_append(void *_arg, struct dentry *dentry)
+{
+ enum d_walk_ret ret;
+ struct ac_dpages_arg *arg = _arg;
+
+ ret = D_WALK_CONTINUE;
+ if (dentry->d_sb == arg->sb
+ && !IS_ROOT(dentry)
+ && au_dcount(dentry) > 0
+ && au_di(dentry)
+ && (!arg->test || arg->test(dentry, arg->arg))) {
+ arg->err = au_dpages_append(arg->dpages, dentry, GFP_ATOMIC);
+ if (unlikely(arg->err))
+ ret = D_WALK_QUIT;
+ }
+
+ return ret;
+}
+
+int au_dcsub_pages(struct au_dcsub_pages *dpages, struct dentry *root,
+ au_dpages_test test, void *arg)
+{
+ struct ac_dpages_arg args = {
+ .err = 0,
+ .dpages = dpages,
+ .sb = root->d_sb,
+ .test = test,
+ .arg = arg
+ };
+
+ d_walk(root, &args, au_call_dpages_append, NULL);
+
+ return args.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;
+ write_seqlock(&rename_lock);
+ spin_lock(&dentry->d_lock);
+ if (do_include
+ && au_dcount(dentry) > 0
+ && (!test || test(dentry, arg)))
+ err = au_dpages_append(dpages, dentry, GFP_ATOMIC);
+ spin_unlock(&dentry->d_lock);
+ if (unlikely(err))
+ goto out;
+
+ /*
+ * RCU for vfsmount is unnecessary since this is a traverse in a single
+ * mount
+ */
+ while (!IS_ROOT(dentry)) {
+ dentry = dentry->d_parent; /* rename_lock is locked */
+ spin_lock(&dentry->d_lock);
+ if (au_dcount(dentry) > 0
+ && (!test || test(dentry, arg)))
+ err = au_dpages_append(dpages, dentry, GFP_ATOMIC);
+ spin_unlock(&dentry->d_lock);
+ if (unlikely(err))
+ break;
+ }
+
+out:
+ write_sequnlock(&rename_lock);
+ return err;
+}
+
+static inline int au_dcsub_dpages_aufs(struct dentry *dentry, void *arg)
+{
+ return au_di(dentry) && dentry->d_sb == arg;
+}
+
+int au_dcsub_pages_rev_aufs(struct au_dcsub_pages *dpages,
+ struct dentry *dentry, int do_include)
+{
+ return au_dcsub_pages_rev(dpages, dentry, do_include,
+ au_dcsub_dpages_aufs, dentry->d_sb);
+}
+
+int au_test_subdir(struct dentry *d1, struct dentry *d2)
+{
+ struct path path[2] = {
+ {
+ .dentry = d1
+ },
+ {
+ .dentry = d2
+ }
+ };
+
+ return path_is_under(path + 0, path + 1);
+}