/*
* ext_attr.c --- extended attribute blocks
- *
- * Copyright (C) Andreas Gruenbacher, <a.gruenbacher@computer.org>
+ *
+ * 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>
#include "ext2fs.h"
-#ifdef EXT2FS_ENABLE_SWAPFS
-void ext2fs_swap_ext_attr(ext2_filsys fs, char *to, char *from)
+#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)
{
- struct ext2_ext_attr_header *from_header =
- (struct ext2_ext_attr_header *)from;
- struct ext2_ext_attr_header *to_header =
- (struct ext2_ext_attr_header *)to;
- struct ext2_ext_attr_entry *from_entry, *to_entry;
- char *from_end = (char *)from_header + fs->blocksize;
+ __u32 hash = 0;
+ char *name = ((char *) entry) + sizeof(struct ext2_ext_attr_entry);
int n;
- if (to_header != from_header)
- memcpy(to_header, from_header, fs->blocksize);
-
- to_header->h_magic = ext2fs_swab32(from_header->h_magic);
- to_header->h_blocks = ext2fs_swab32(from_header->h_blocks);
- to_header->h_refcount = ext2fs_swab32(from_header->h_refcount);
- for (n=0; n<4; n++)
- to_header->h_reserved[n] =
- ext2fs_swab32(from_header->h_reserved[n]);
-
- from_entry = (struct ext2_ext_attr_entry *)(from_header+1);
- to_entry = (struct ext2_ext_attr_entry *)(to_header+1);
- while ((char *)from_entry < from_end && *(__u32 *)from_entry) {
- to_entry->e_value_offs =
- ext2fs_swab16(from_entry->e_value_offs);
- to_entry->e_value_block =
- ext2fs_swab32(from_entry->e_value_block);
- to_entry->e_value_size =
- ext2fs_swab32(from_entry->e_value_size);
- from_entry = EXT2_EXT_ATTR_NEXT(from_entry);
- to_entry = EXT2_EXT_ATTR_NEXT(to_entry);
+ 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_blk64(fs->io, block, 1, buf);
+ if (retval)
+ return retval;
+#ifdef WORDS_BIGENDIAN
+ ext2fs_swap_ext_attr(buf, buf, fs->blocksize, 1);
#endif
+ return 0;
+}
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;
- struct ext2_ext_attr_entry *entry;
+ char *write_buf;
+#ifdef WORDS_BIGENDIAN
+ char *buf = NULL;
- retval = io_channel_read_blk(fs->io, block, 1, buf);
+ retval = ext2fs_get_mem(fs->blocksize, &buf);
if (retval)
return retval;
-#ifdef EXT2FS_ENABLE_SWAPFS
- if ((fs->flags & (EXT2_FLAG_SWAP_BYTES|
- EXT2_FLAG_SWAP_BYTES_READ)) != 0)
- ext2fs_swap_ext_attr(fs, buf, buf);
+ write_buf = buf;
+ ext2fs_swap_ext_attr(buf, inbuf, fs->blocksize, 1);
+#else
+ write_buf = (char *) inbuf;
#endif
- return 0;
+ 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_refcount2(ext2_filsys fs, blk64_t blk,
+ char *block_buf, int adjust,
+ __u32 *newcount)
+{
errcode_t retval;
- char *p, *end, *write_buf;
- char *buf = NULL;
- struct ext2_dir_entry *dirent;
+ struct ext2_ext_attr_header *header;
+ char *buf = 0;
-#ifdef EXT2FS_ENABLE_SWAPFS
- if ((fs->flags & EXT2_FLAG_SWAP_BYTES) ||
- (fs->flags & EXT2_FLAG_SWAP_BYTES_WRITE)) {
- retval = ext2fs_get_mem(fs->blocksize, (void **) &buf);
+ if ((blk >= ext2fs_blocks_count(fs->super)) ||
+ (blk < fs->super->s_first_data_block))
+ return EXT2_ET_BAD_EA_BLOCK_NUM;
+
+ if (!block_buf) {
+ retval = ext2fs_get_mem(fs->blocksize, &buf);
if (retval)
return retval;
- write_buf = buf;
- ext2fs_swap_ext_attr(fs, buf, inbuf);
- } else
-#endif
- write_buf = (char *) inbuf;
- retval = io_channel_write_blk(fs->io, block, 1, write_buf);
+ block_buf = buf;
+ }
+
+ retval = ext2fs_read_ext_attr2(fs, blk, block_buf);
+ if (retval)
+ goto errout;
+
+ header = (struct ext2_ext_attr_header *) block_buf;
+ header->h_refcount += adjust;
+ if (newcount)
+ *newcount = header->h_refcount;
+
+ retval = ext2fs_write_ext_attr2(fs, blk, block_buf);
+ if (retval)
+ goto errout;
+
+errout:
if (buf)
- ext2fs_free_mem((void **) &buf);
- if (!retval)
- ext2fs_mark_changed(fs);
+ 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);
+}
git://git.whamcloud.com / tools / e2fsprogs.git / blobdiff