[PATCH 07/10] AXFS: axfs_bdev.c

Jared Hulbert
2008-08-21T05:45:37Z

All the block device code goes here.

Signed-off-by: Jared Hulbert <jaredeh@gmail.com>
---
diff --git a/fs/axfs/axfs_bdev.c b/fs/axfs/axfs_bdev.c
new file mode 100644
index 0000000..4c6f83c
--- /dev/null
+++ b/fs/axfs/axfs_bdev.c
@@ -0,0 +1,158 @@
+/*
+ * Advanced XIP File System for Linux - AXFS
+ * Readonly, compressed, and XIP filesystem for Linux systems big and small
+ *
+ * Copyright(c) 2008 Numonyx
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * Authors:
+ * Jared Hulbert <jaredeh@gmail.com>
+ *
+ * Project url: http://axfs.sourceforge.net
+ *
+ * axfs_bdev.c -
+ * Allows axfs to use block devices or has dummy functions if block
+ * device support is compiled out of the kernel.
+ *
+ */
+
+#include <linux/axfs.h>
+#include <linux/mount.h>
+#ifdef CONFIG_BLOCK
+#include <linux/buffer_head.h>
+#include <linux/namei.h>
+
+int axfs_fill_super(struct super_block *sb, void *data, int silent);
+
+int axfs_get_sb_bdev(struct file_system_type *fs_type, int flags,
+ const char *dev_name, struct axfs_super *sbi,
+ struct vfsmount *mnt, int *err)
+{
+ *err = get_sb_bdev(fs_type, flags, dev_name, sbi, axfs_fill_super, mnt);
+
+ if (*err)
+ return FALSE;
+ return TRUE;
+}
+
+void axfs_kill_block_super(struct super_block *sb)
+{
+ kill_block_super(sb);
+}
+
+/******************************************************************************
+ *
+ * axfs_copy_block_data
+ *
+ * Description: Helper function to read data from block device
+ *
+ * Parameters:
+ * (IN) sb - pointer to super block structure.
+ *
+ * (IN) dst_addr - pointer to buffer into which data is to be read.
+ *
+ * (IN) boffset - offset within block device
+ *
+ * (IN) len - length of data to be read
+ *
+ * Returns:
+ * 0 or error number
+ *
+ *****************************************************************************/
+int axfs_copy_block(struct super_block *sb, void *dst_addr, u64 fsoffset,
+ u64 len)
+{
+ struct axfs_super *sbi = AXFS_SB(sb);
+ u64 boffset = AXFS_FSOFFSET_2_DEVOFFSET(sbi, fsoffset);
+ u64 blocks;
+ u64 blksize = sb->s_blocksize;
+ unsigned long dst;
+ unsigned long src;
+ sector_t block;
+ size_t bytes;
+ struct buffer_head *bh;
+ u64 copied = 0;
+
+ if (len == 0)
+ return 0;
+
+ blocks = len / blksize;
+ if ((len % blksize) > 0)
+ blocks += 1;
+
+ while (copied < len) {
+ /* Explicit casting for ARM linker errors. */
+ block = (sector_t) boffset + (sector_t) copied;
+ block /= (sector_t) blksize;
+ bh = sb_bread(sb, block);
+ src = (unsigned long)bh->b_data;
+ dst = (unsigned long)dst_addr;
+ if (copied == 0) {
+ /* Explicit casting for ARM linker errors. */
+ bytes = (size_t) blksize;
+ bytes -= (size_t) boffset % (size_t) blksize;
+ if (bytes > len)
+ bytes = len;
+ /* Explicit casting for ARM linker errors. */
+ src += (unsigned long)boffset % (unsigned long)blksize;
+ } else {
+ dst += copied;
+ if ((len - copied) < blksize) {
+ bytes = len - copied;
+ } else {
+ bytes = blksize;
+ }
+ }
+ memcpy((void *)dst, (void *)src, bytes);
+ copied += bytes;
+ brelse(bh);
+ }
+ return 0;
+}
+
+int axfs_is_dev_bdev(char *path)
+{
+ struct nameidata nd;
+ int ret = FALSE;
+
+ if (!path)
+ return FALSE;
+
+ if (path_lookup(path, LOOKUP_FOLLOW, &nd))
+ return FALSE;
+
+ if (S_ISBLK(nd.path.dentry->d_inode->i_mode))
+ ret = TRUE;
+
+ path_put(&nd.path);
+ return ret;
+}
+
+#else
+
+int axfs_get_sb_bdev(struct file_system_type *fs_type, int flags,
+ const char *dev_name, struct axfs_super *sbi,
+ struct vfsmount *mnt, int *err)
+{
+ return FALSE;
+}
+
+void axfs_kill_block_super(struct super_block *sb)
+{
+}
+
+int axfs_copy_block(struct super_block *sb, void *dst_addr, u64 fsoffset,
+ u64 len)
+{
+ return -EINVAL;
+}
+
+int axfs_is_dev_bdev(char *path)
+{
+ return FALSE;
+}
+
+#endif /* CONFIG_BLOCK */