patch-2.4.10 linux/fs/jffs2/read.c
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- Lines: 158
- Date:
Fri Sep 14 14:04:07 2001
- Orig file:
v2.4.9/linux/fs/jffs2/read.c
- Orig date:
Wed Dec 31 16:00:00 1969
diff -u --recursive --new-file v2.4.9/linux/fs/jffs2/read.c linux/fs/jffs2/read.c
@@ -0,0 +1,157 @@
+/*
+ * JFFS2 -- Journalling Flash File System, Version 2.
+ *
+ * Copyright (C) 2001 Red Hat, Inc.
+ *
+ * Created by David Woodhouse <dwmw2@cambridge.redhat.com>
+ *
+ * The original JFFS, from which the design for JFFS2 was derived,
+ * was designed and implemented by Axis Communications AB.
+ *
+ * The contents of this file are subject to the Red Hat eCos Public
+ * License Version 1.1 (the "Licence"); you may not use this file
+ * except in compliance with the Licence. You may obtain a copy of
+ * the Licence at http://www.redhat.com/
+ *
+ * Software distributed under the Licence is distributed on an "AS IS"
+ * basis, WITHOUT WARRANTY OF ANY KIND, either express or implied.
+ * See the Licence for the specific language governing rights and
+ * limitations under the Licence.
+ *
+ * The Original Code is JFFS2 - Journalling Flash File System, version 2
+ *
+ * Alternatively, the contents of this file may be used under the
+ * terms of the GNU General Public License version 2 (the "GPL"), in
+ * which case the provisions of the GPL are applicable instead of the
+ * above. If you wish to allow the use of your version of this file
+ * only under the terms of the GPL and not to allow others to use your
+ * version of this file under the RHEPL, indicate your decision by
+ * deleting the provisions above and replace them with the notice and
+ * other provisions required by the GPL. If you do not delete the
+ * provisions above, a recipient may use your version of this file
+ * under either the RHEPL or the GPL.
+ *
+ * $Id: read.c,v 1.13 2001/05/01 16:24:44 dwmw2 Exp $
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/jffs2.h>
+#include <linux/mtd/mtd.h>
+#include "nodelist.h"
+#include "crc32.h"
+
+int jffs2_read_dnode(struct jffs2_sb_info *c, struct jffs2_full_dnode *fd, unsigned char *buf, int ofs, int len)
+{
+ struct jffs2_raw_inode *ri;
+ size_t readlen;
+ __u32 crc;
+ unsigned char *decomprbuf = NULL;
+ unsigned char *readbuf = NULL;
+ int ret = 0;
+
+ ri = jffs2_alloc_raw_inode();
+ if (!ri)
+ return -ENOMEM;
+
+ ret = c->mtd->read(c->mtd, fd->raw->flash_offset & ~3, sizeof(*ri), &readlen, (char *)ri);
+ if (ret) {
+ jffs2_free_raw_inode(ri);
+ printk(KERN_WARNING "Error reading node from 0x%08x: %d\n", fd->raw->flash_offset & ~3, ret);
+ return ret;
+ }
+ if (readlen != sizeof(*ri)) {
+ jffs2_free_raw_inode(ri);
+ printk(KERN_WARNING "Short read from 0x%08x: wanted 0x%x bytes, got 0x%x\n",
+ fd->raw->flash_offset & ~3, sizeof(*ri), readlen);
+ return -EIO;
+ }
+ crc = crc32(0, ri, sizeof(*ri)-8);
+
+ D1(printk(KERN_DEBUG "Node read from %08x: node_crc %08x, calculated CRC %08x. dsize %x, csize %x, offset %x, buf %p\n", fd->raw->flash_offset & ~3, ri->node_crc, crc, ri->dsize, ri->csize, ri->offset, buf));
+ if (crc != ri->node_crc) {
+ printk(KERN_WARNING "Node CRC %08x != calculated CRC %08x for node at %08x\n", ri->node_crc, crc, fd->raw->flash_offset & ~3);
+ ret = -EIO;
+ goto out_ri;
+ }
+
+ D1(if(ofs + len > ri->dsize) {
+ printk(KERN_WARNING "jffs2_read_dnode() asked for %d bytes at %d from %d-byte node\n", len, ofs, ri->dsize);
+ ret = -EINVAL;
+ goto out_ri;
+ });
+
+
+ if (ri->compr == JFFS2_COMPR_ZERO) {
+ memset(buf, 0, len);
+ goto out_ri;
+ }
+
+ /* Cases:
+ Reading whole node and it's uncompressed - read directly to buffer provided, check CRC.
+ Reading whole node and it's compressed - read into comprbuf, check CRC and decompress to buffer provided
+ Reading partial node and it's uncompressed - read into readbuf, check CRC, and copy
+ Reading partial node and it's compressed - read into readbuf, check checksum, decompress to decomprbuf and copy
+ */
+ if (ri->compr == JFFS2_COMPR_NONE && len == ri->dsize) {
+ readbuf = buf;
+ } else {
+ readbuf = kmalloc(ri->csize, GFP_KERNEL);
+ if (!readbuf) {
+ ret = -ENOMEM;
+ goto out_ri;
+ }
+ }
+ if (ri->compr != JFFS2_COMPR_NONE) {
+ if (len < ri->dsize) {
+ decomprbuf = kmalloc(ri->dsize, GFP_KERNEL);
+ if (!decomprbuf) {
+ ret = -ENOMEM;
+ goto out_readbuf;
+ }
+ } else {
+ decomprbuf = buf;
+ }
+ } else {
+ decomprbuf = readbuf;
+ }
+
+ D2(printk(KERN_DEBUG "Read %d bytes to %p\n", ri->csize, readbuf));
+ ret = c->mtd->read(c->mtd, (fd->raw->flash_offset &~3) + sizeof(*ri), ri->csize, &readlen, readbuf);
+
+ if (!ret && readlen != ri->csize)
+ ret = -EIO;
+ if (ret)
+ goto out_decomprbuf;
+
+ crc = crc32(0, readbuf, ri->csize);
+ if (crc != ri->data_crc) {
+ printk(KERN_WARNING "Data CRC %08x != calculated CRC %08x for node at %08x\n", ri->data_crc, crc, fd->raw->flash_offset & ~3);
+ ret = -EIO;
+ goto out_decomprbuf;
+ }
+ D2(printk(KERN_DEBUG "Data CRC matches calculated CRC %08x\n", crc));
+ if (ri->compr != JFFS2_COMPR_NONE) {
+ D2(printk(KERN_DEBUG "Decompress %d bytes from %p to %d bytes at %p\n", ri->csize, readbuf, ri->dsize, decomprbuf));
+ ret = jffs2_decompress(ri->compr, readbuf, decomprbuf, ri->csize, ri->dsize);
+ if (ret) {
+ printk(KERN_WARNING "Error: jffs2_decompress returned %d\n", ret);
+ goto out_decomprbuf;
+ }
+ }
+
+ if (len < ri->dsize) {
+ memcpy(buf, decomprbuf+ofs, len);
+ }
+ out_decomprbuf:
+ if(decomprbuf != buf && decomprbuf != readbuf)
+ kfree(decomprbuf);
+ out_readbuf:
+ if(readbuf != buf)
+ kfree(readbuf);
+ out_ri:
+ jffs2_free_raw_inode(ri);
+
+ return ret;
+}
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