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authorPhillip Lougher <phillip@lougher.demon.co.uk>2010-05-14 20:48:47 +0100
committerPhillip Lougher <phillip@lougher.demon.co.uk>2010-05-17 19:54:05 +0100
commit4b5397dc24ab12afaac85be3d0863b7f6eb8b0f0 (patch)
treebd385be428cfefcdf520f19c532196df1202d687 /fs/squashfs/xattr_id.c
parentb57f95a38233a2e73b679bea4a5453a1cc2a1cc9 (diff)
squashfs: add xattr id support
This patch adds support for mapping xattr ids (stored in inodes) into the on-disk location of the xattrs themselves. Signed-off-by: Phillip Lougher <phillip@lougher.demon.co.uk>
Diffstat (limited to 'fs/squashfs/xattr_id.c')
-rw-r--r--fs/squashfs/xattr_id.c100
1 files changed, 100 insertions, 0 deletions
diff --git a/fs/squashfs/xattr_id.c b/fs/squashfs/xattr_id.c
new file mode 100644
index 00000000000..a74101244a9
--- /dev/null
+++ b/fs/squashfs/xattr_id.c
@@ -0,0 +1,100 @@
+/*
+ * Squashfs - a compressed read only filesystem for Linux
+ *
+ * Copyright (c) 2010
+ * Phillip Lougher <phillip@lougher.demon.co.uk>
+ *
+ * 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,
+ * 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, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ * xattr_id.c
+ */
+
+/*
+ * This file implements code to map the 32-bit xattr id stored in the inode
+ * into the on disk location of the xattr data.
+ */
+
+#include <linux/fs.h>
+#include <linux/vfs.h>
+#include <linux/slab.h>
+
+#include "squashfs_fs.h"
+#include "squashfs_fs_sb.h"
+#include "squashfs_fs_i.h"
+#include "squashfs.h"
+
+/*
+ * Map xattr id using the xattr id look up table
+ */
+int squashfs_xattr_lookup(struct super_block *sb, unsigned int index,
+ int *count, int *size, long long *xattr)
+{
+ struct squashfs_sb_info *msblk = sb->s_fs_info;
+ int block = SQUASHFS_XATTR_BLOCK(index);
+ int offset = SQUASHFS_XATTR_BLOCK_OFFSET(index);
+ u64 start_block = le64_to_cpu(msblk->xattr_id_table[block]);
+ struct squashfs_xattr_id id;
+ int err;
+
+ err = squashfs_read_metadata(sb, &id, &start_block, &offset,
+ sizeof(id));
+ if (err < 0)
+ return err;
+
+ *xattr = le64_to_cpu(id.xattr);
+ *size = le32_to_cpu(id.size);
+ *count = le32_to_cpu(id.count);
+ return 0;
+}
+
+
+/*
+ * Read uncompressed xattr id lookup table indexes from disk into memory
+ */
+__le64 *squashfs_read_xattr_id_table(struct super_block *sb, u64 start,
+ u64 *xattr_table_start, int *xattr_ids)
+{
+ unsigned int len;
+ __le64 *xid_table;
+ struct squashfs_xattr_id_table id_table;
+ int err;
+
+ err = squashfs_read_table(sb, &id_table, start, sizeof(id_table));
+ if (err < 0) {
+ ERROR("unable to read xattr id table\n");
+ return ERR_PTR(err);
+ }
+ *xattr_table_start = le64_to_cpu(id_table.xattr_table_start);
+ *xattr_ids = le32_to_cpu(id_table.xattr_ids);
+ len = SQUASHFS_XATTR_BLOCK_BYTES(*xattr_ids);
+
+ TRACE("In read_xattr_index_table, length %d\n", len);
+
+ /* Allocate xattr id lookup table indexes */
+ xid_table = kmalloc(len, GFP_KERNEL);
+ if (xid_table == NULL) {
+ ERROR("Failed to allocate xattr id index table\n");
+ return ERR_PTR(-ENOMEM);
+ }
+
+ err = squashfs_read_table(sb, xid_table, start + sizeof(id_table), len);
+ if (err < 0) {
+ ERROR("unable to read xattr id index table\n");
+ kfree(xid_table);
+ return ERR_PTR(err);
+ }
+
+ return xid_table;
+}