hfsplus: implement attributes file's header node initialization code

Implement functionality of AttributesFile's header node initialization.

Signed-off-by: Vyacheslav Dubeyko <slava@dubeyko.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Hin-Tak Leung <htl10@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/fs/hfsplus/hfsplus_raw.h b/fs/hfsplus/hfsplus_raw.h
index 2c54dd8..8ffb3a8 100644 (file)
--- a/fs/hfsplus/hfsplus_raw.h
+++ b/fs/hfsplus/hfsplus_raw.h
@@ -187,6 +187,9 @@ struct hfs_btree_header_rec {
 /* HFS+ BTree misc info */
 #define HFSPLUS_TREE_HEAD 0
 #define HFSPLUS_NODE_MXSZ 32768
+#define HFSPLUS_ATTR_TREE_NODE_SIZE            8192
+#define HFSPLUS_BTREE_HDR_NODE_RECS_COUNT      3
+#define HFSPLUS_BTREE_HDR_USER_BYTES           128
 
 /* Some special File ID numbers (stolen from hfs.h) */
 #define HFSPLUS_POR_CNID               1       /* Parent Of the Root */

diff --git a/fs/hfsplus/xattr.c b/fs/hfsplus/xattr.c
index bd8471f..568a45c 100644 (file)
--- a/fs/hfsplus/xattr.c
+++ b/fs/hfsplus/xattr.c
@@ -127,6 +127,71 @@ static int can_set_xattr(struct inode *inode, const char *name,
        return 0;
 }
 
+static void hfsplus_init_header_node(struct inode *attr_file,
+                                       u32 clump_size,
+                                       char *buf, size_t node_size)
+{
+       struct hfs_bnode_desc *desc;
+       struct hfs_btree_header_rec *head;
+       u16 offset;
+       __be16 *rec_offsets;
+       u32 hdr_node_map_rec_bits;
+       char *bmp;
+       u32 used_nodes;
+       u32 used_bmp_bytes;
+
+       hfs_dbg(ATTR_MOD, "init_hdr_attr_file: clump %u, node_size %zu\n",
+                               clump_size, node_size);
+
+       /* The end of the node contains list of record offsets */
+       rec_offsets = (__be16 *)(buf + node_size);
+
+       desc = (struct hfs_bnode_desc *)buf;
+       desc->type = HFS_NODE_HEADER;
+       desc->num_recs = cpu_to_be16(HFSPLUS_BTREE_HDR_NODE_RECS_COUNT);
+       offset = sizeof(struct hfs_bnode_desc);
+       *--rec_offsets = cpu_to_be16(offset);
+
+       head = (struct hfs_btree_header_rec *)(buf + offset);
+       head->node_size = cpu_to_be16(node_size);
+       head->node_count = cpu_to_be32(i_size_read(attr_file) / node_size);
+       head->free_nodes = cpu_to_be32(be32_to_cpu(head->node_count) - 1);
+       head->clump_size = cpu_to_be32(clump_size);
+       head->attributes |= cpu_to_be32(HFS_TREE_BIGKEYS | HFS_TREE_VARIDXKEYS);
+       head->max_key_len = cpu_to_be16(HFSPLUS_ATTR_KEYLEN - sizeof(u16));
+       offset += sizeof(struct hfs_btree_header_rec);
+       *--rec_offsets = cpu_to_be16(offset);
+       offset += HFSPLUS_BTREE_HDR_USER_BYTES;
+       *--rec_offsets = cpu_to_be16(offset);
+
+       hdr_node_map_rec_bits = 8 * (node_size - offset - (4 * sizeof(u16)));
+       if (be32_to_cpu(head->node_count) > hdr_node_map_rec_bits) {
+               u32 map_node_bits;
+               u32 map_nodes;
+
+               desc->next = cpu_to_be32(be32_to_cpu(head->leaf_tail) + 1);
+               map_node_bits = 8 * (node_size - sizeof(struct hfs_bnode_desc) -
+                                       (2 * sizeof(u16)) - 2);
+               map_nodes = (be32_to_cpu(head->node_count) -
+                               hdr_node_map_rec_bits +
+                               (map_node_bits - 1)) / map_node_bits;
+               be32_add_cpu(&head->free_nodes, 0 - map_nodes);
+       }
+
+       bmp = buf + offset;
+       used_nodes =
+               be32_to_cpu(head->node_count) - be32_to_cpu(head->free_nodes);
+       used_bmp_bytes = used_nodes / 8;
+       if (used_bmp_bytes) {
+               memset(bmp, 0xFF, used_bmp_bytes);
+               bmp += used_bmp_bytes;
+               used_nodes %= 8;
+       }
+       *bmp = ~(0xFF >> used_nodes);
+       offset += hdr_node_map_rec_bits / 8;
+       *--rec_offsets = cpu_to_be16(offset);
+}
+
 int __hfsplus_setxattr(struct inode *inode, const char *name,
                        const void *value, size_t size, int flags)
 {