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-rw-r--r--fs/aufs/procfs.c169
1 files changed, 169 insertions, 0 deletions
diff --git a/fs/aufs/procfs.c b/fs/aufs/procfs.c
new file mode 100644
index 000000000..772be91a9
--- /dev/null
+++ b/fs/aufs/procfs.c
@@ -0,0 +1,169 @@
+/*
+ * Copyright (C) 2010-2015 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/>.
+ */
+
+/*
+ * procfs interfaces
+ */
+
+#include <linux/proc_fs.h>
+#include "aufs.h"
+
+static int au_procfs_plm_release(struct inode *inode, struct file *file)
+{
+ struct au_sbinfo *sbinfo;
+
+ sbinfo = file->private_data;
+ if (sbinfo) {
+ au_plink_maint_leave(sbinfo);
+ kobject_put(&sbinfo->si_kobj);
+ }
+
+ return 0;
+}
+
+static void au_procfs_plm_write_clean(struct file *file)
+{
+ struct au_sbinfo *sbinfo;
+
+ sbinfo = file->private_data;
+ if (sbinfo)
+ au_plink_clean(sbinfo->si_sb, /*verbose*/0);
+}
+
+static int au_procfs_plm_write_si(struct file *file, unsigned long id)
+{
+ int err;
+ struct super_block *sb;
+ struct au_sbinfo *sbinfo;
+
+ err = -EBUSY;
+ if (unlikely(file->private_data))
+ goto out;
+
+ sb = NULL;
+ /* don't use au_sbilist_lock() here */
+ spin_lock(&au_sbilist.spin);
+ list_for_each_entry(sbinfo, &au_sbilist.head, si_list)
+ if (id == sysaufs_si_id(sbinfo)) {
+ kobject_get(&sbinfo->si_kobj);
+ sb = sbinfo->si_sb;
+ break;
+ }
+ spin_unlock(&au_sbilist.spin);
+
+ err = -EINVAL;
+ if (unlikely(!sb))
+ goto out;
+
+ err = au_plink_maint_enter(sb);
+ if (!err)
+ /* keep kobject_get() */
+ file->private_data = sbinfo;
+ else
+ kobject_put(&sbinfo->si_kobj);
+out:
+ return err;
+}
+
+/*
+ * Accept a valid "si=xxxx" only.
+ * Once it is accepted successfully, accept "clean" too.
+ */
+static ssize_t au_procfs_plm_write(struct file *file, const char __user *ubuf,
+ size_t count, loff_t *ppos)
+{
+ ssize_t err;
+ unsigned long id;
+ /* last newline is allowed */
+ char buf[3 + sizeof(unsigned long) * 2 + 1];
+
+ err = -EACCES;
+ if (unlikely(!capable(CAP_SYS_ADMIN)))
+ goto out;
+
+ err = -EINVAL;
+ if (unlikely(count > sizeof(buf)))
+ goto out;
+
+ err = copy_from_user(buf, ubuf, count);
+ if (unlikely(err)) {
+ err = -EFAULT;
+ goto out;
+ }
+ buf[count] = 0;
+
+ err = -EINVAL;
+ if (!strcmp("clean", buf)) {
+ au_procfs_plm_write_clean(file);
+ goto out_success;
+ } else if (unlikely(strncmp("si=", buf, 3)))
+ goto out;
+
+ err = kstrtoul(buf + 3, 16, &id);
+ if (unlikely(err))
+ goto out;
+
+ err = au_procfs_plm_write_si(file, id);
+ if (unlikely(err))
+ goto out;
+
+out_success:
+ err = count; /* success */
+out:
+ return err;
+}
+
+static const struct file_operations au_procfs_plm_fop = {
+ .write = au_procfs_plm_write,
+ .release = au_procfs_plm_release,
+ .owner = THIS_MODULE
+};
+
+/* ---------------------------------------------------------------------- */
+
+static struct proc_dir_entry *au_procfs_dir;
+
+void au_procfs_fin(void)
+{
+ remove_proc_entry(AUFS_PLINK_MAINT_NAME, au_procfs_dir);
+ remove_proc_entry(AUFS_PLINK_MAINT_DIR, NULL);
+}
+
+int __init au_procfs_init(void)
+{
+ int err;
+ struct proc_dir_entry *entry;
+
+ err = -ENOMEM;
+ au_procfs_dir = proc_mkdir(AUFS_PLINK_MAINT_DIR, NULL);
+ if (unlikely(!au_procfs_dir))
+ goto out;
+
+ entry = proc_create(AUFS_PLINK_MAINT_NAME, S_IFREG | S_IWUSR,
+ au_procfs_dir, &au_procfs_plm_fop);
+ if (unlikely(!entry))
+ goto out_dir;
+
+ err = 0;
+ goto out; /* success */
+
+
+out_dir:
+ remove_proc_entry(AUFS_PLINK_MAINT_DIR, NULL);
+out:
+ return err;
+}