Signed-off-by: Josef 'Jeff' Sipek <jeffpc@xxxxxxxxxxxxxx>
---
fs/cmsfs/bmap.c | 104 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 104 insertions(+), 0 deletions(-)
create mode 100644 fs/cmsfs/bmap.c
diff --git a/fs/cmsfs/bmap.c b/fs/cmsfs/bmap.c
new file mode 100644
index 0000000..ce9eccf
--- /dev/null
+++ b/fs/cmsfs/bmap.c
@@ -0,0 +1,104 @@
+/*
+ * CMSFS
+ *
+ * (C) 2008 Josef 'Jeff' Sipek <jeffpc@xxxxxxxxxxxxxx>
+ *
+ * Based on cmsfs from 2.4.12-ac6:
+ *
+ * (C) 2001 Rick Troth <rtroth@xxxxxxx>
+ * (C) 2001 BMC Software, Inc., Houston, Texas, USA
+ *
+ */
+
+#include <linux/mm.h>
+#include <linux/slab.h>
+#include <linux/fs.h>
+#include <linux/buffer_head.h>
+#include <linux/mpage.h>
+
+#include "cmsfs.h"
+
+/**
+ * cmsfs_get_blocks - map a inode offset to a disk block
+ * @inode: inode to map
+ * @iblock: inode offset to map (in fs blocks)
+ * @bh_result: resulting buffer_head
+ * @create: ?
+ */
+static int cmsfs_get_blocks(struct inode *inode, sector_t iblock,
+ struct buffer_head *bh_result, int create)
+{
+ struct cmsfs_inode_info *cinode = CMSFS_I(inode);
+ struct super_block *sb = inode->i_sb;
+ struct buffer_head *bh;
+
+ BUG_ON(create);
+
+ /* indirection? */
+ if (cinode->level != 0) {
+ int ptrs_per_blk;
+ int i, lvl;
+ void *bp;
+ u32 b1, b2;
+
+ b2 = ~0; /* to avoid potentially uninit var warning */
+
+ /* pointers per block */
+ if (cinode->psize > 0)
+ ptrs_per_blk = CMSFS_SB(sb)->blksz / cinode->psize;
+ else
+ ptrs_per_blk = CMSFS_SB(sb)->blksz / 4;
+
+ /* read first block for indirection */
+ b1 = iblock;
+ for (i = 0; i < cinode->level; i++)
+ b1 = b1 / ptrs_per_blk;
+ bh = sb_bread(sb, cinode->origin - 1 + b1);
+ if (!bh)
+ goto fail;
+
+ for (lvl = 1; lvl <= cinode->level; lvl++) {
+ /* read next block for indirection */
+ b1 = iblock;
+ for (i = lvl; i < cinode->level; i++)
+ b1 = b1 / ptrs_per_blk;
+ b1 = b1 % ptrs_per_blk;
+ bp = bh->b_data;
+ bp += b1 * cinode->psize;
+ b2 = be32_to_cpu(*(u32*)bp);
+
+ brelse(bh);
+
+ /* read next block for indirection */
+ bh = sb_bread(sb, b2 - 1);
+ if (!bh)
+ goto fail;
+ }
+
+ clear_buffer_new(bh_result);
+ map_bh(bh_result, inode->i_sb, b2-1);
+ } else {
+ clear_buffer_new(bh_result);
+ map_bh(bh_result, inode->i_sb,
+ cinode->origin - 1 + iblock);
+ }
+
+ return 0;
+
+fail:
+ return -EIO;
+}
+
+/**
+ * cmsfs_readpage - read a page for an inode
+ * @unused: (unused)
+ * @page: page to read
+ */
+static int cmsfs_readpage(struct file *unused, struct page *page)
+{
+ return mpage_readpage(page, cmsfs_get_blocks);
+}
+
+struct address_space_operations cmsfs_aops = {
+ .readpage = cmsfs_readpage,
+};
--
1.5.6.3
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