From: Junjiro Okajima <hooanon05@xxxxxxxxxxx>
initial commit
aufs as a readonly branch of another aufs
Signed-off-by: Junjiro Okajima <hooanon05@xxxxxxxxxxx>
---
fs/aufs/robr.c | 109 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 109 insertions(+), 0 deletions(-)
create mode 100644 fs/aufs/robr.c
diff --git a/fs/aufs/robr.c b/fs/aufs/robr.c
new file mode 100644
index 0000000..64ec128
--- /dev/null
+++ b/fs/aufs/robr.c
@@ -0,0 +1,109 @@
+/*
+ * Copyright (C) 2008 Junjiro 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, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+/*
+ * 'robr', aufs as readonly branch of another aufs
+ */
+
+#include "aufs.h"
+
+/* ---------------------------------------------------------------------- */
+
+int au_test_robr_wh(struct qstr *name, struct dentry *h_parent,
+ struct qstr *wh_name, int try_sio, struct au_ndx *ndx)
+{
+ if (strncmp(name->name, AUFS_WH_PFX, AUFS_WH_PFX_LEN))
+ return au_wh_test(h_parent, wh_name, try_sio, ndx);
+ return -EPERM;
+}
+
+int au_test_robr_shwh(struct super_block *sb, const struct qstr *name)
+{
+ return 0;
+}
+
+/* ---------------------------------------------------------------------- */
+
+struct au_robr_lvma {
+ struct list_head list;
+ struct vm_area_struct *vma;
+};
+
+struct file *au_robr_safe_file(struct vm_area_struct *vma)
+{
+ struct file *file = vma->vm_file;
+ struct super_block *sb = file->f_dentry->d_sb;
+ struct au_robr_lvma *lvma, *entry;
+ struct au_sbinfo *sbinfo;
+ int found, warn;
+
+ AuTraceEnter();
+ AuDebugOn(!au_test_aufs(sb));
+
+ warn = 0;
+ found = 0;
+ sbinfo = au_sbi(sb);
+ spin_lock(&sbinfo->si_lvma_lock);
+ list_for_each_entry(entry, &sbinfo->si_lvma, list) {
+ found = (entry->vma == vma);
+ if (unlikely(found))
+ break;
+ }
+ if (!found) {
+ lvma = kmalloc(sizeof(*lvma), GFP_ATOMIC);
+ if (lvma) {
+ lvma->vma = vma;
+ list_add(&lvma->list, &sbinfo->si_lvma);
+ } else {
+ warn = 1;
+ file = NULL;
+ }
+ } else
+ file = NULL;
+ spin_unlock(&sbinfo->si_lvma_lock);
+
+ if (unlikely(warn))
+ AuWarn1("no memory for lvma\n");
+ return file;
+}
+
+void au_robr_reset_file(struct vm_area_struct *vma, struct file *file)
+{
+ struct super_block *sb = file->f_dentry->d_sb;
+ struct au_robr_lvma *entry, *found;
+ struct au_sbinfo *sbinfo;
+
+ AuTraceEnter();
+ AuDebugOn(!au_test_aufs(sb));
+
+ vma->vm_file = file;
+ /* smp_mb(); */ /* flush vm_file */
+
+ found = NULL;
+ sbinfo = au_sbi(sb);
+ spin_lock(&sbinfo->si_lvma_lock);
+ list_for_each_entry(entry, &sbinfo->si_lvma, list)
+ if (entry->vma == vma) {
+ found = entry;
+ break;
+ }
+ AuDebugOn(!found);
+ list_del(&found->list);
+ spin_unlock(&sbinfo->si_lvma_lock);
+ kfree(found);
+}
--
1.5.5.1.308.g1fbb5.dirty
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