libext2fs: precompute FS UUID checksum seed

[tools/e2fsprogs.git] / lib / ext2fs / ext_attr.c

diff --git a/lib/ext2fs/ext_attr.c b/lib/ext2fs/ext_attr.c
index ee5fe16..1889824 100644 (file)
--- a/lib/ext2fs/ext_attr.c
+++ b/lib/ext2fs/ext_attr.c
@@ -1,16 +1,17 @@
 /*
  * ext_attr.c --- extended attribute blocks
- * 
+ *
  * Copyright (C) 2001 Andreas Gruenbacher, <a.gruenbacher@computer.org>
  *
  * Copyright (C) 2002 Theodore Ts'o.
  *
  * %Begin-Header%
- * This file may be redistributed under the terms of the GNU Public
- * License.
+ * This file may be redistributed under the terms of the GNU Library
+ * General Public License, version 2.
  * %End-Header%
  */
 
+#include "config.h"
 #include <stdio.h>
 #if HAVE_UNISTD_H
 #include <unistd.h>
@@ -23,11 +24,48 @@
 
 #include "ext2fs.h"
 
-errcode_t ext2fs_read_ext_attr(ext2_filsys fs, blk_t block, void *buf)
+#define NAME_HASH_SHIFT 5
+#define VALUE_HASH_SHIFT 16
+
+/*
+ * ext2_xattr_hash_entry()
+ *
+ * Compute the hash of an extended attribute.
+ */
+__u32 ext2fs_ext_attr_hash_entry(struct ext2_ext_attr_entry *entry, void *data)
+{
+       __u32 hash = 0;
+       char *name = ((char *) entry) + sizeof(struct ext2_ext_attr_entry);
+       int n;
+
+       for (n = 0; n < entry->e_name_len; n++) {
+               hash = (hash << NAME_HASH_SHIFT) ^
+                      (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^
+                      *name++;
+       }
+
+       /* The hash needs to be calculated on the data in little-endian. */
+       if (entry->e_value_block == 0 && entry->e_value_size != 0) {
+               __u32 *value = (__u32 *)data;
+               for (n = (entry->e_value_size + EXT2_EXT_ATTR_ROUND) >>
+                        EXT2_EXT_ATTR_PAD_BITS; n; n--) {
+                       hash = (hash << VALUE_HASH_SHIFT) ^
+                              (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^
+                              ext2fs_le32_to_cpu(*value++);
+               }
+       }
+
+       return hash;
+}
+
+#undef NAME_HASH_SHIFT
+#undef VALUE_HASH_SHIFT
+
+errcode_t ext2fs_read_ext_attr2(ext2_filsys fs, blk64_t block, void *buf)
 {
        errcode_t       retval;
 
-       retval = io_channel_read_blk(fs->io, block, 1, buf);
+       retval = io_channel_read_blk64(fs->io, block, 1, buf);
        if (retval)
                return retval;
 #ifdef WORDS_BIGENDIAN
@@ -36,13 +74,18 @@ errcode_t ext2fs_read_ext_attr(ext2_filsys fs, blk_t block, void *buf)
        return 0;
 }
 
-errcode_t ext2fs_write_ext_attr(ext2_filsys fs, blk_t block, void *inbuf)
+errcode_t ext2fs_read_ext_attr(ext2_filsys fs, blk_t block, void *buf)
+{
+       return ext2fs_read_ext_attr2(fs, block, buf);
+}
+
+errcode_t ext2fs_write_ext_attr2(ext2_filsys fs, blk64_t block, void *inbuf)
 {
        errcode_t       retval;
        char            *write_buf;
+#ifdef WORDS_BIGENDIAN
        char            *buf = NULL;
 
-#ifdef WORDS_BIGENDIAN
        retval = ext2fs_get_mem(fs->blocksize, &buf);
        if (retval)
                return retval;
@@ -51,18 +94,24 @@ errcode_t ext2fs_write_ext_attr(ext2_filsys fs, blk_t block, void *inbuf)
 #else
        write_buf = (char *) inbuf;
 #endif
-       retval = io_channel_write_blk(fs->io, block, 1, write_buf);
-       if (buf)
-               ext2fs_free_mem(&buf);
+       retval = io_channel_write_blk64(fs->io, block, 1, write_buf);
+#ifdef WORDS_BIGENDIAN
+       ext2fs_free_mem(&buf);
+#endif
        if (!retval)
                ext2fs_mark_changed(fs);
        return retval;
 }
 
+errcode_t ext2fs_write_ext_attr(ext2_filsys fs, blk_t block, void *inbuf)
+{
+       return ext2fs_write_ext_attr2(fs, block, inbuf);
+}
+
 /*
  * This function adjusts the reference count of the EA block.
  */
-errcode_t ext2fs_adjust_ea_refcount(ext2_filsys fs, blk_t blk,
+errcode_t ext2fs_adjust_ea_refcount2(ext2_filsys fs, blk64_t blk,
                                    char *block_buf, int adjust,
                                    __u32 *newcount)
 {
@@ -70,7 +119,7 @@ errcode_t ext2fs_adjust_ea_refcount(ext2_filsys fs, blk_t blk,
        struct ext2_ext_attr_header *header;
        char    *buf = 0;
 
-       if ((blk >= fs->super->s_blocks_count) ||
+       if ((blk >= ext2fs_blocks_count(fs->super)) ||
            (blk < fs->super->s_first_data_block))
                return EXT2_ET_BAD_EA_BLOCK_NUM;
 
@@ -81,7 +130,7 @@ errcode_t ext2fs_adjust_ea_refcount(ext2_filsys fs, blk_t blk,
                block_buf = buf;
        }
 
-       retval = ext2fs_read_ext_attr(fs, blk, block_buf);
+       retval = ext2fs_read_ext_attr2(fs, blk, block_buf);
        if (retval)
                goto errout;
 
@@ -90,7 +139,7 @@ errcode_t ext2fs_adjust_ea_refcount(ext2_filsys fs, blk_t blk,
        if (newcount)
                *newcount = header->h_refcount;
 
-       retval = ext2fs_write_ext_attr(fs, blk, block_buf);
+       retval = ext2fs_write_ext_attr2(fs, blk, block_buf);
        if (retval)
                goto errout;
 
@@ -99,3 +148,10 @@ errout:
                ext2fs_free_mem(&buf);
        return retval;
 }
+
+errcode_t ext2fs_adjust_ea_refcount(ext2_filsys fs, blk_t blk,
+                                       char *block_buf, int adjust,
+                                       __u32 *newcount)
+{
+       return ext2fs_adjust_ea_refcount(fs, blk, block_buf, adjust, newcount);
+}