--- /dev/null
+/* cf-xattr.c: CacheFiles extended attribute management
+ *
+ * Copyright (C) 2006 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program 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.
+ */
+
+#include <linux/module.h>
+#include <linux/sched.h>
+#include <linux/file.h>
+#include <linux/fs.h>
+#include <linux/fsnotify.h>
+#include <linux/quotaops.h>
+#include <linux/xattr.h>
+#include "internal.h"
+
+static const char cachefiles_xattr_cache[] = XATTR_USER_PREFIX "CacheFiles.cache";
+
+/*****************************************************************************/
+/*
+ * check the type label on an object
+ * - done using xattrs
+ */
+int cachefiles_check_object_type(struct cachefiles_object *object)
+{
+ struct dentry *dentry = object->dentry;
+ char type[3], xtype[3];
+ int ret;
+
+ ASSERT(dentry);
+ ASSERT(dentry->d_inode);
+ ASSERT(dentry->d_inode->i_op);
+ ASSERT(dentry->d_inode->i_op->setxattr);
+ ASSERT(dentry->d_inode->i_op->getxattr);
+
+ if (!object->fscache.cookie)
+ strcpy(type, "C3");
+ else
+ snprintf(type, 3, "%02x", object->fscache.cookie->def->type);
+
+ _enter("%p{%s}", object, type);
+
+ mutex_lock(&dentry->d_inode->i_mutex);
+
+ /* attempt to install a type label directly */
+ ret = dentry->d_inode->i_op->setxattr(dentry, cachefiles_xattr_cache,
+ type, 2, XATTR_CREATE);
+ if (ret == 0) {
+ _debug("SET");
+ fsnotify_xattr(dentry);
+ mutex_unlock(&dentry->d_inode->i_mutex);
+ goto error;
+ }
+
+ if (ret != -EEXIST) {
+ kerror("Can't set xattr on %*.*s [%lu] (err %d)",
+ dentry->d_name.len, dentry->d_name.len,
+ dentry->d_name.name, dentry->d_inode->i_ino,
+ -ret);
+ goto error;
+ }
+
+ /* read the current type label */
+ ret = dentry->d_inode->i_op->getxattr(dentry, cachefiles_xattr_cache,
+ xtype, 3);
+ if (ret < 0) {
+ if (ret == -ERANGE)
+ goto bad_type_length;
+
+ kerror("Can't read xattr on %*.*s [%lu] (err %d)",
+ dentry->d_name.len, dentry->d_name.len,
+ dentry->d_name.name, dentry->d_inode->i_ino,
+ -ret);
+ goto error;
+ }
+
+ /* check the type is what we're expecting */
+ if (ret != 2)
+ goto bad_type_length;
+
+ if (xtype[0] != type[0] || xtype[1] != type[1])
+ goto bad_type;
+
+ ret = 0;
+
+error:
+ mutex_unlock(&dentry->d_inode->i_mutex);
+ _leave(" = %d", ret);
+ return ret;
+
+bad_type_length:
+ kerror("Cache object %lu type xattr length incorrect",
+ dentry->d_inode->i_ino);
+ ret = -EIO;
+ goto error;
+
+bad_type:
+ xtype[2] = 0;
+ kerror("Cache object %*.*s [%lu] type %s not %s",
+ dentry->d_name.len, dentry->d_name.len,
+ dentry->d_name.name, dentry->d_inode->i_ino,
+ xtype, type);
+ ret = -EIO;
+ goto error;
+}
+
+/*****************************************************************************/
+/*
+ * set the state xattr on a cache file
+ */
+int cachefiles_set_object_xattr(struct cachefiles_object *object,
+ struct cachefiles_xattr *auxdata)
+{
+ struct dentry *dentry = object->dentry;
+ int ret;
+
+ ASSERT(object->fscache.cookie);
+ ASSERT(dentry);
+ ASSERT(dentry->d_inode->i_op->setxattr);
+
+ _enter("%p,#%d", object, auxdata->len);
+
+ /* attempt to install the cache metadata directly */
+ mutex_lock(&dentry->d_inode->i_mutex);
+
+ _debug("SET %s #%u",
+ object->fscache.cookie->def->name, auxdata->len);
+
+ ret = dentry->d_inode->i_op->setxattr(dentry, cachefiles_xattr_cache,
+ &auxdata->type, auxdata->len,
+ XATTR_CREATE);
+ if (ret == 0)
+ fsnotify_xattr(dentry);
+ else if (ret != -ENOMEM)
+ cachefiles_io_error_obj(object,
+ "Failed to set xattr with error %d",
+ ret);
+
+ mutex_unlock(&dentry->d_inode->i_mutex);
+ _leave(" = %d", ret);
+ return ret;
+}
+
+/*****************************************************************************/
+/*
+ * check the state xattr on a cache file
+ * - return -ESTALE if the object should be deleted
+ */
+int cachefiles_check_object_xattr(struct cachefiles_object *object,
+ struct cachefiles_xattr *auxdata)
+{
+ struct cachefiles_xattr *auxbuf;
+ struct dentry *dentry = object->dentry;
+ int ret;
+
+ _enter("%p,#%d", object, auxdata->len);
+
+ ASSERT(dentry);
+ ASSERT(dentry->d_inode);
+ ASSERT(dentry->d_inode->i_op->setxattr);
+ ASSERT(dentry->d_inode->i_op->getxattr);
+
+ auxbuf = kmalloc(sizeof(struct cachefiles_xattr) + 512, GFP_KERNEL);
+ if (!auxbuf) {
+ _leave(" = -ENOMEM");
+ return -ENOMEM;
+ }
+
+ mutex_lock(&dentry->d_inode->i_mutex);
+
+ /* read the current type label */
+ ret = dentry->d_inode->i_op->getxattr(dentry, cachefiles_xattr_cache,
+ &auxbuf->type, 512 + 1);
+ if (ret < 0) {
+ if (ret == -ENODATA)
+ goto stale; /* no attribute - power went off
+ * mid-cull? */
+
+ if (ret == -ERANGE)
+ goto bad_type_length;
+
+ cachefiles_io_error_obj(object,
+ "can't read xattr on %lu (err %d)",
+ dentry->d_inode->i_ino, -ret);
+ goto error;
+ }
+
+ /* check the on-disk object */
+ if (ret < 1)
+ goto bad_type_length;
+
+ if (auxbuf->type != auxdata->type)
+ goto stale;
+
+ auxbuf->len = ret;
+
+ /* consult the netfs */
+ if (object->fscache.cookie->def->check_aux) {
+ fscache_checkaux_t result;
+ unsigned int dlen;
+
+ dlen = auxbuf->len - 1;
+
+ _debug("checkaux %s #%u",
+ object->fscache.cookie->def->name, dlen);
+
+ result = object->fscache.cookie->def->check_aux(
+ object->fscache.cookie->netfs_data,
+ &auxbuf->data, dlen);
+
+ switch (result) {
+ /* entry okay as is */
+ case FSCACHE_CHECKAUX_OKAY:
+ goto okay;
+
+ /* entry requires update */
+ case FSCACHE_CHECKAUX_NEEDS_UPDATE:
+ break;
+
+ /* entry requires deletion */
+ case FSCACHE_CHECKAUX_OBSOLETE:
+ goto stale;
+
+ default:
+ BUG();
+ }
+
+ /* update the current label */
+ ret = dentry->d_inode->i_op->setxattr(dentry,
+ cachefiles_xattr_cache,
+ &auxdata->type,
+ auxdata->len,
+ XATTR_REPLACE);
+ if (ret < 0) {
+ cachefiles_io_error_obj(object,
+ "Can't update xattr on %lu"
+ " (error %d)",
+ dentry->d_inode->i_ino, -ret);
+ goto error;
+ }
+ }
+
+okay:
+ ret = 0;
+
+error:
+ mutex_unlock(&dentry->d_inode->i_mutex);
+ kfree(auxbuf);
+ _leave(" = %d", ret);
+ return ret;
+
+bad_type_length:
+ kerror("Cache object %lu xattr length incorrect",
+ dentry->d_inode->i_ino);
+ ret = -EIO;
+ goto error;
+
+stale:
+ ret = -ESTALE;
+ goto error;
+}
+
+/*****************************************************************************/
+/*
+ * remove the object's xattr to mark it stale
+ */
+int cachefiles_remove_object_xattr(struct cachefiles_cache *cache,
+ struct dentry *dentry)
+{
+ int ret;
+
+ mutex_lock(&dentry->d_inode->i_mutex);
+
+ ret = dentry->d_inode->i_op->removexattr(dentry,
+ cachefiles_xattr_cache);
+
+ mutex_unlock(&dentry->d_inode->i_mutex);
+
+ if (ret < 0) {
+ if (ret == -ENOENT || ret == -ENODATA)
+ ret = 0;
+ else if (ret != -ENOMEM)
+ cachefiles_io_error(cache,
+ "Can't remove xattr from %lu"
+ " (error %d)",
+ dentry->d_inode->i_ino, -ret);
+ }
+
+ _leave(" = %d", ret);
+ return ret;
+}
git://git.onelab.eu / linux-2.6.git / blobdiff