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

• Lines: 151
• Date: Mon Apr 1 21:23:46 1996
• Orig file: v1.3.93/linux/fs/affs/dir.c
• Orig date: Thu Jan 1 02:00:00 1970

diff -u --recursive --new-file v1.3.93/linux/fs/affs/dir.c linux/fs/affs/dir.c
@@ -0,0 +1,150 @@
+/*
+ *  linux/fs/affs/dir.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 directory handling functions
+ */
+
+#include <linux/errno.h>
+
+#include <asm/segment.h>
+
+#include <linux/fs.h>
+#include <linux/affs_fs.h>
+#include <linux/kernel.h>
+#include <linux/affs_fs.h>
+#include <linux/stat.h>
+#include <linux/string.h>
+#include <linux/sched.h>
+
+static int affs_readdir(struct inode *, struct file *, void *, filldir_t);
+
+struct file_operations affs_dir_operations = {
+	NULL,			/* lseek - default */
+	NULL,			/* read */
+	NULL,			/* write - bad */
+	affs_readdir,		/* readdir */
+	NULL,			/* select - default */
+	NULL,			/* ioctl - default */
+	NULL,			/* mmap */
+	NULL,			/* no special open code */
+	NULL,			/* no special release code */
+	NULL			/* fsync */
+};
+
+/*
+ * directories can handle most operations...
+ */
+struct inode_operations affs_dir_inode_operations = {
+	&affs_dir_operations,	/* default directory file-ops */
+	NULL,			/* create */
+	affs_lookup,		/* lookup */
+	NULL,			/* link */
+	NULL,       		/* unlink */
+	NULL,       		/* symlink */
+	NULL,       		/* mkdir */
+	NULL,			/* rmdir */
+	NULL,			/* mknod */
+	NULL,			/* rename */
+	NULL,			/* readlink */
+	NULL,			/* follow_link */
+	NULL,			/* bmap */
+	NULL,			/* truncate */
+	NULL			/* permission */
+};
+
+/* This is used to speed up lookup.  Without this we would need to
+make a linear search of the directory to find the file that the
+directory read just returned.  This is a single element cache. */
+
+/* struct lookup_cache cache = {0,}; */
+
+static int affs_readdir(struct inode * inode, struct file * filp,
+	void * dirent, filldir_t filldir)
+{
+	int i, j, chain_pos, hash_pos, reclen, ino;
+	char *name;
+	struct buffer_head *dir_bh;
+	struct buffer_head *fh_bh;
+	void *dir_data;
+	void *fh_data;
+
+#ifdef DEBUG
+	printk ("AFFS: readdir: inode=%d f_pos=%d\n",
+		inode->i_ino, filp->f_pos);
+#endif
+	
+	if (!inode || !S_ISDIR(inode->i_mode))
+		return -EBADF;
+
+	while ((unsigned long)filp->f_pos < 2) {
+		if (filp->f_pos == 0) {
+			if (filldir (dirent, ".", 1, filp->f_pos, inode->i_ino) < 0)
+				return 0;
+		} else {
+			i = affs_parent_ino (inode);
+			if (filldir (dirent, "..", 2, filp->f_pos, i) < 0)
+				return 0;
+		}
+		filp->f_pos++;
+	}
+	/* No caching here.  I've got 16 megs why should I care?  :-) */
+	chain_pos = (filp->f_pos - 2) & 0xffff;
+	if (chain_pos == 0xffff)
+		return 0;
+	hash_pos = (filp->f_pos - 2) >> 16;
+#ifdef DEBUG
+	printk ("AFFS: hash_pos=%d chain_pos=%d\n", hash_pos, chain_pos);
+#endif
+	if (!(dir_bh = affs_pread(inode, inode->i_ino, &dir_data)))
+		return 0;
+	/* HASH_POS should already be on a used entry unless it is
+	   the first read of the directory.  Will this break the
+	   dirtell thing somehow? */
+	i = affs_find_next_hash_entry (AFFS_I2BSIZE (inode), dir_data,
+				       &hash_pos);
+	j = chain_pos;
+	for (;;) {
+		if (i <= 0) {
+#ifdef DEBUG
+			printk ("AFFS: bad f_pos in readdir\n");
+#endif
+			brelse (dir_bh);
+			return 0;
+		}
+		ino = i;
+		if (!(fh_bh = affs_pread (inode, i, &fh_data))) {
+			brelse (dir_bh);
+			return 0;
+		}
+		i = affs_get_fh_hash_link (AFFS_I2BSIZE (inode), fh_data);
+		if (j == 0) {
+			j = 1;
+			if (i <= 0) {
+				hash_pos++;
+				i = affs_find_next_hash_entry (AFFS_I2BSIZE (inode),
+							       dir_data, &hash_pos);
+				if (i <= 0)
+					chain_pos = 0xffff;
+				else
+					chain_pos = 0;
+			} else
+				chain_pos++;
+			reclen = affs_get_file_name (AFFS_I2BSIZE (inode),
+						     fh_data, &name);
+			if (filldir (dirent, name, reclen, filp->f_pos, ino) < 0) {
+				brelse (fh_bh);
+				brelse (dir_bh);
+				return 0;
+			}
+			filp->f_pos = ((hash_pos << 16) | chain_pos) + 2;
+		}
+		brelse (fh_bh);
+		j--;
+	}
+}