patch-1.3.94 linux/fs/affs/file.c

• Lines: 175
• Date: Sat Mar 30 18:37:05 1996
• Orig file: v1.3.93/linux/fs/affs/file.c
• Orig date: Thu Jan 1 02:00:00 1970

diff -u --recursive --new-file v1.3.93/linux/fs/affs/file.c linux/fs/affs/file.c
@@ -0,0 +1,174 @@
+/*
+ *  linux/fs/affs/file.c
+ *
+ *  (C) 1993  Ray Burr - Modified for Amiga FFS filesystem.
+ *
+ *  (C) 1992  Eric Youngdale Modified for ISO9660 filesystem.
+ *
+ *  (C) 1991  Linus Torvalds - minix filesystem
+ *
+ *  affs regular file handling primitives
+ */
+
+#include <asm/segment.h>
+#include <asm/system.h>
+
+#include <linux/sched.h>
+#include <linux/affs_fs.h>
+#include <linux/fcntl.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/stat.h>
+#include <linux/locks.h>
+
+#include <linux/dirent.h>
+
+#define	NBUF	16
+
+#define MIN(a,b) (((a)<(b))?(a):(b))
+#define MAX(a,b) (((a)>(b))?(a):(b))
+
+#include <linux/fs.h>
+#include <linux/affs_fs.h>
+
+#include "amigaffs.h"
+
+int affs_file_read(struct inode *, struct file *, char *, int);
+
+/*
+ * We have mostly NULL's here: the current defaults are ok for
+ * the affs filesystem.
+ */
+struct file_operations affs_file_operations = {
+	NULL,			/* lseek - default */
+	affs_file_read,		/* read */
+	NULL,			/* write */
+	NULL,			/* readdir - bad */
+	NULL,			/* select - default */
+	NULL,			/* ioctl - default */
+	generic_file_mmap,	/* mmap */
+	NULL,			/* no special open is needed */
+	NULL,			/* release */
+	NULL			/* can't fsync */
+};
+
+struct inode_operations affs_file_inode_operations = {
+	&affs_file_operations,	/* default file operations */
+	NULL,			/* create */
+	NULL,			/* lookup */
+	NULL,			/* link */
+	NULL,			/* unlink */
+	NULL,			/* symlink */
+	NULL,			/* mkdir */
+	NULL,			/* rmdir */
+	NULL,			/* mknod */
+	NULL,			/* rename */
+	NULL,			/* readlink */
+	NULL,			/* follow_link */
+	NULL /* affs_bmap */,		/* bmap */
+	NULL,			/* truncate */
+	NULL			/* permission */
+};
+
+static int affs_smap(struct inode *inode, int block)
+{
+	struct buffer_head *bh;
+	int key;
+	void *fh_data;
+
+/* FIXME */
+#define KEY_SLOTS_PER_BLOCK 72
+
+#ifdef DEBUG
+	printk ("affs_smap: ino=%d block=%d\n", inode->i_ino, block);
+#endif
+
+	if (block < 0) {
+		printk("affs_smap: block < 0");
+		return 0;
+	}
+
+	key = inode->i_ino;
+	for (;;) {
+		bh = affs_pread (inode, key, &fh_data);
+		if (!bh)
+			return 0;
+		if (block < KEY_SLOTS_PER_BLOCK)
+			break;
+		block -= KEY_SLOTS_PER_BLOCK;
+		key = affs_get_extension (AFFS_I2BSIZE (inode), fh_data);
+#ifdef DEBUG
+		printk ("affs_smap: reading extension block %d\n", key);
+#endif
+		brelse (bh);
+	}
+	key = affs_get_key_entry (AFFS_I2BSIZE (inode), fh_data,
+				  (KEY_SLOTS_PER_BLOCK - 1) - block);
+	brelse (bh);
+
+#ifdef DEBUG
+	printk ("affs_smap: key=%d\n", key);
+#endif
+	return key;
+}
+
+/*
+ * affs_file_read() is also needed by the directory read-routine,
+ * so it's not static. NOTE! reading directories directly is a bad idea,
+ * but has to be supported for now for compatability reasons with older
+ * versions.
+ */
+int affs_file_read(struct inode * inode, struct file * filp,
+		   char * buf, int count)
+{
+	char *start;
+	int left, offset, size, sector;
+	struct buffer_head *bh;
+	void *data;
+
+	if (!inode) {
+		printk("affs_file_read: inode = NULL\n");
+		return -EINVAL;
+	}
+	if (!(S_ISREG(inode->i_mode))) {
+#ifdef DEBUG
+		printk("affs_file_read: mode = %07o\n",inode->i_mode);
+#endif
+		return -EINVAL;
+	}
+	if (filp->f_pos >= inode->i_size || count <= 0)
+		return 0;
+
+	start = buf;
+	for (;;) {
+		left = MIN (inode->i_size - filp->f_pos,
+			    count - (buf - start));
+		if (!left)
+			break;
+		sector = affs_smap (inode, filp->f_pos >> AFFS_BLOCK_BITS);
+		if (!sector)
+			break;
+		offset = filp->f_pos & (AFFS_BLOCK_SIZE - 1);
+		bh = affs_pread (inode, sector, &data);
+		if (!bh)
+			break;
+		size = MIN (AFFS_BLOCK_SIZE - offset, left);
+		filp->f_pos += size;
+		memcpy_tofs (buf, data + offset, size);
+		buf += size;
+		brelse (bh);
+	}
+	if (start == buf)
+		return -EIO;
+	return buf - start;
+
+#if 0
+	if (filp->f_pos == 0 && count > 0) {
+		put_fs_byte ('X', buf++);
+		filp->f_pos++;
+		return 1;
+	}
+	else
+		return 0;
+#endif
+}