[PATCH 21/29] Unionfs: extended attributes operations

From: Erez Zadok
Date: Thu Jan 10 2008 - 10:09:52 EST


Signed-off-by: Erez Zadok <ezk@xxxxxxxxxxxxx>
---
fs/unionfs/xattr.c | 153 ++++++++++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 153 insertions(+), 0 deletions(-)
create mode 100644 fs/unionfs/xattr.c

diff --git a/fs/unionfs/xattr.c b/fs/unionfs/xattr.c
new file mode 100644
index 0000000..8001c65
--- /dev/null
+++ b/fs/unionfs/xattr.c
@@ -0,0 +1,153 @@
+/*
+ * Copyright (c) 2003-2007 Erez Zadok
+ * Copyright (c) 2003-2006 Charles P. Wright
+ * Copyright (c) 2005-2007 Josef 'Jeff' Sipek
+ * Copyright (c) 2005-2006 Junjiro Okajima
+ * Copyright (c) 2005 Arun M. Krishnakumar
+ * Copyright (c) 2004-2006 David P. Quigley
+ * Copyright (c) 2003-2004 Mohammad Nayyer Zubair
+ * Copyright (c) 2003 Puja Gupta
+ * Copyright (c) 2003 Harikesavan Krishnan
+ * Copyright (c) 2003-2007 Stony Brook University
+ * Copyright (c) 2003-2007 The Research Foundation of SUNY
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include "union.h"
+
+/* This is lifted from fs/xattr.c */
+void *unionfs_xattr_alloc(size_t size, size_t limit)
+{
+ void *ptr;
+
+ if (size > limit)
+ return ERR_PTR(-E2BIG);
+
+ if (!size) /* size request, no buffer is needed */
+ return NULL;
+
+ ptr = kmalloc(size, GFP_KERNEL);
+ if (unlikely(!ptr))
+ return ERR_PTR(-ENOMEM);
+ return ptr;
+}
+
+/*
+ * BKL held by caller.
+ * dentry->d_inode->i_mutex locked
+ */
+ssize_t unionfs_getxattr(struct dentry *dentry, const char *name, void *value,
+ size_t size)
+{
+ struct dentry *lower_dentry = NULL;
+ int err = -EOPNOTSUPP;
+
+ unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_CHILD);
+ unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
+
+ if (unlikely(!__unionfs_d_revalidate_chain(dentry, NULL, false))) {
+ err = -ESTALE;
+ goto out;
+ }
+
+ lower_dentry = unionfs_lower_dentry(dentry);
+
+ err = vfs_getxattr(lower_dentry, (char *) name, value, size);
+
+out:
+ unionfs_check_dentry(dentry);
+ unionfs_unlock_dentry(dentry);
+ unionfs_read_unlock(dentry->d_sb);
+ return err;
+}
+
+/*
+ * BKL held by caller.
+ * dentry->d_inode->i_mutex locked
+ */
+int unionfs_setxattr(struct dentry *dentry, const char *name,
+ const void *value, size_t size, int flags)
+{
+ struct dentry *lower_dentry = NULL;
+ int err = -EOPNOTSUPP;
+
+ unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_CHILD);
+ unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
+
+ if (unlikely(!__unionfs_d_revalidate_chain(dentry, NULL, false))) {
+ err = -ESTALE;
+ goto out;
+ }
+
+ lower_dentry = unionfs_lower_dentry(dentry);
+
+ err = vfs_setxattr(lower_dentry, (char *) name, (void *) value,
+ size, flags);
+
+out:
+ unionfs_check_dentry(dentry);
+ unionfs_unlock_dentry(dentry);
+ unionfs_read_unlock(dentry->d_sb);
+ return err;
+}
+
+/*
+ * BKL held by caller.
+ * dentry->d_inode->i_mutex locked
+ */
+int unionfs_removexattr(struct dentry *dentry, const char *name)
+{
+ struct dentry *lower_dentry = NULL;
+ int err = -EOPNOTSUPP;
+
+ unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_CHILD);
+ unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
+
+ if (unlikely(!__unionfs_d_revalidate_chain(dentry, NULL, false))) {
+ err = -ESTALE;
+ goto out;
+ }
+
+ lower_dentry = unionfs_lower_dentry(dentry);
+
+ err = vfs_removexattr(lower_dentry, (char *) name);
+
+out:
+ unionfs_check_dentry(dentry);
+ unionfs_unlock_dentry(dentry);
+ unionfs_read_unlock(dentry->d_sb);
+ return err;
+}
+
+/*
+ * BKL held by caller.
+ * dentry->d_inode->i_mutex locked
+ */
+ssize_t unionfs_listxattr(struct dentry *dentry, char *list, size_t size)
+{
+ struct dentry *lower_dentry = NULL;
+ int err = -EOPNOTSUPP;
+ char *encoded_list = NULL;
+
+ unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_CHILD);
+ unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
+
+ if (unlikely(!__unionfs_d_revalidate_chain(dentry, NULL, false))) {
+ err = -ESTALE;
+ goto out;
+ }
+
+ lower_dentry = unionfs_lower_dentry(dentry);
+
+ encoded_list = list;
+ err = vfs_listxattr(lower_dentry, encoded_list, size);
+
+out:
+ unionfs_check_dentry(dentry);
+ unionfs_unlock_dentry(dentry);
+ unionfs_read_unlock(dentry->d_sb);
+ return err;
+}
--
1.5.2.2

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