1 files changed, 344 insertions, 0 deletions
diff --git a/fs/squashfs/super.c b/fs/squashfs/super.c
new file mode 100644
index 0000000000..4c730e09e4
--- /dev/null
+++ b/fs/squashfs/super.c
@@ -0,0 +1,344 @@
+/*
+ * Squashfs - a compressed read only filesystem for Linux
+ *
+ * Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008
+ * Phillip Lougher <phillip@squashfs.org.uk>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2,
+ * or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * super.c
+ */
+
+/*
+ * This file implements code to read the superblock, read and initialise
+ * in-memory structures at mount time, and all the VFS glue code to register
+ * the filesystem.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <errno.h>
+#include <linux/fs.h>
+#include <linux/kernel.h>
+#include <linux/pagemap.h>
+#include <linux/magic.h>
+#include <linux/bitops.h>
+
+#include "page_actor.h"
+#include "squashfs_fs.h"
+#include "squashfs_fs_sb.h"
+#include "squashfs_fs_i.h"
+#include "squashfs.h"
+#include "decompressor.h"
+
+static struct dentry *d_make_root(struct inode *inode)
+{
+	struct dentry *de = malloc(sizeof(struct dentry));
+	de->d_name.name = "/";
+	de->d_name.len = strlen("/");
+	de->d_inode = inode;
+	return de;
+}
+
+static const struct squashfs_decompressor *supported_squashfs_filesystem(short
+	major, short minor, short id)
+{
+	const struct squashfs_decompressor *decompressor;
+
+	if (major < SQUASHFS_MAJOR) {
+		ERROR("Major/Minor mismatch, older Squashfs %d.%d "
+			"filesystems are unsupported\n", major, minor);
+		return NULL;
+	} else if (major > SQUASHFS_MAJOR || minor > SQUASHFS_MINOR) {
+		ERROR("Major/Minor mismatch, trying to mount newer "
+			"%d.%d filesystem\n", major, minor);
+		ERROR("Please update your kernel\n");
+		return NULL;
+	}
+
+	decompressor = squashfs_lookup_decompressor(id);
+	if (!decompressor->supported) {
+		ERROR("Filesystem uses \"%s\" compression. This is not "
+			"supported\n", decompressor->name);
+		return NULL;
+	}
+
+	return decompressor;
+}
+
+void squashfs_put_super(struct super_block *sb)
+{
+	if (sb->s_fs_info) {
+		struct squashfs_sb_info *sbi = sb->s_fs_info;
+		squashfs_cache_delete(sbi->block_cache);
+		squashfs_cache_delete(sbi->fragment_cache);
+		squashfs_cache_delete(sbi->read_page);
+		squashfs_decompressor_destroy(sbi);
+		kfree(sbi->id_table);
+		kfree(sbi->fragment_index);
+		kfree(sbi->meta_index);
+		kfree(sbi->inode_lookup_table);
+		kfree(sbi->xattr_id_table);
+		kfree(sb->s_fs_info);
+		sb->s_fs_info = NULL;
+	}
+
+	if (sb->s_root) {
+		kfree(squashfs_i(sb->s_root->d_inode));
+		kfree(sb->s_root);
+		sb->s_root = NULL;
+	}
+}
+
+static int squashfs_fill_super(struct super_block *sb, void *data, int silent)
+{
+	struct squashfs_sb_info *msblk;
+	struct fs_device_d *fsdev = (struct fs_device_d *)data;
+	struct squashfs_super_block *sblk = NULL;
+	struct inode *root;
+	long long root_inode;
+	unsigned short flags;
+	unsigned int fragments;
+	u64 lookup_table_start, next_table;
+	int err;
+
+	TRACE("Entered squashfs_fill_superblock\n");
+
+	sb->s_fs_info = kzalloc(sizeof(*msblk), GFP_KERNEL);
+	if (sb->s_fs_info == NULL) {
+		ERROR("Failed to allocate squashfs_sb_info\n");
+		return -ENOMEM;
+	}
+	msblk = sb->s_fs_info;
+	msblk->cdev = fsdev->cdev;
+	msblk->dev = &fsdev->dev;
+
+	msblk->devblksize = 1024;
+	msblk->devblksize_log2 = ffz(~msblk->devblksize);
+
+	mutex_init(&msblk->meta_index_mutex);
+	/*
+	 * msblk->bytes_used is checked in squashfs_read_table to ensure reads
+	 * are not beyond filesystem end.  But as we're using
+	 * squashfs_read_table here to read the superblock (including the value
+	 * of bytes_used) we need to set it to an initial sensible dummy value
+	 */
+	msblk->bytes_used = sizeof(*sblk);
+	sblk = squashfs_read_table(sb, SQUASHFS_START, sizeof(*sblk));
+
+	if (IS_ERR(sblk)) {
+		ERROR("unable to read squashfs_super_block\n");
+		err = PTR_ERR(sblk);
+		sblk = NULL;
+		goto failed_mount;
+	}
+
+	err = -EINVAL;
+
+	/* Check it is a SQUASHFS superblock */
+	sb->s_magic = le32_to_cpu(sblk->s_magic);
+	if (sb->s_magic != SQUASHFS_MAGIC) {
+		if (!silent)
+			ERROR("Can't find a SQUASHFS superblock on %pg\n",
+						sb->s_bdev);
+		goto failed_mount;
+	}
+
+	/* Check the MAJOR & MINOR versions and lookup compression type */
+	msblk->decompressor = supported_squashfs_filesystem(
+			le16_to_cpu(sblk->s_major),
+			le16_to_cpu(sblk->s_minor),
+			le16_to_cpu(sblk->compression));
+	if (msblk->decompressor == NULL)
+		goto failed_mount;
+
+	/* Check the filesystem does not extend beyond the end of the
+	   block device */
+	msblk->bytes_used = le64_to_cpu(sblk->bytes_used);
+	if (msblk->bytes_used < 0 || msblk->bytes_used >
+			msblk->cdev->size)
+		goto failed_mount;
+
+	/* Check block size for sanity */
+	msblk->block_size = le32_to_cpu(sblk->block_size);
+	if (msblk->block_size > SQUASHFS_FILE_MAX_SIZE)
+		goto failed_mount;
+
+	/*
+	 * Check the system page size is not larger than the filesystem
+	 * block size (by default 128K).  This is currently not supported.
+	 */
+	if (PAGE_CACHE_SIZE > msblk->block_size) {
+		ERROR("Page size > filesystem block size (%d).  This is "
+			"currently not supported!\n", msblk->block_size);
+		goto failed_mount;
+	}
+
+	/* Check block log for sanity */
+	msblk->block_log = le16_to_cpu(sblk->block_log);
+	if (msblk->block_log > SQUASHFS_FILE_MAX_LOG)
+		goto failed_mount;
+
+	/* Check that block_size and block_log match */
+	if (msblk->block_size != (1 << msblk->block_log))
+		goto failed_mount;
+
+	/* Check the root inode for sanity */
+	root_inode = le64_to_cpu(sblk->root_inode);
+	if (SQUASHFS_INODE_OFFSET(root_inode) > SQUASHFS_METADATA_SIZE)
+		goto failed_mount;
+
+	msblk->inode_table = le64_to_cpu(sblk->inode_table_start);
+	msblk->directory_table = le64_to_cpu(sblk->directory_table_start);
+	msblk->inodes = le32_to_cpu(sblk->inodes);
+	flags = le16_to_cpu(sblk->flags);
+
+	TRACE("Found valid superblock on %pg\n", sb->s_bdev);
+	TRACE("Inodes are %scompressed\n", SQUASHFS_UNCOMPRESSED_INODES(flags)
+				? "un" : "");
+	TRACE("Data is %scompressed\n", SQUASHFS_UNCOMPRESSED_DATA(flags)
+				? "un" : "");
+	TRACE("Filesystem size %lld bytes\n", msblk->bytes_used);
+	TRACE("Block size %d\n", msblk->block_size);
+	TRACE("Number of inodes %d\n", msblk->inodes);
+	TRACE("Number of fragments %d\n", le32_to_cpu(sblk->fragments));
+	TRACE("Number of ids %d\n", le16_to_cpu(sblk->no_ids));
+	TRACE("sblk->inode_table_start %llx\n", msblk->inode_table);
+	TRACE("sblk->directory_table_start %llx\n", msblk->directory_table);
+	TRACE("sblk->fragment_table_start %llx\n",
+		(u64) le64_to_cpu(sblk->fragment_table_start));
+	TRACE("sblk->id_table_start %llx\n",
+		(u64) le64_to_cpu(sblk->id_table_start));
+
+	sb->s_maxbytes = MAX_LFS_FILESIZE;
+	sb->s_flags |= MS_RDONLY;
+
+	err = -ENOMEM;
+
+	msblk->block_cache = squashfs_cache_init("metadata",
+			SQUASHFS_CACHED_BLKS, SQUASHFS_METADATA_SIZE);
+	if (msblk->block_cache == NULL)
+		goto failed_mount;
+
+	/* Allocate read_page block */
+	msblk->read_page = squashfs_cache_init("data",
+		squashfs_max_decompressors(), msblk->block_size);
+	if (msblk->read_page == NULL) {
+		ERROR("Failed to allocate read_page block\n");
+		goto failed_mount;
+	}
+
+	msblk->stream = squashfs_decompressor_setup(sb, flags);
+	if (IS_ERR(msblk->stream)) {
+		err = PTR_ERR(msblk->stream);
+		msblk->stream = NULL;
+		goto failed_mount;
+	}
+
+	next_table = msblk->bytes_used;
+
+	/* Allocate and read id index table */
+	msblk->id_table = squashfs_read_id_index_table(sb,
+		le64_to_cpu(sblk->id_table_start), next_table,
+		le16_to_cpu(sblk->no_ids));
+	if (IS_ERR(msblk->id_table)) {
+		ERROR("unable to read id index table\n");
+		err = PTR_ERR(msblk->id_table);
+		msblk->id_table = NULL;
+		goto failed_mount;
+	}
+	next_table = le64_to_cpu(msblk->id_table[0]);
+
+	/* Handle inode lookup table */
+	lookup_table_start = le64_to_cpu(sblk->lookup_table_start);
+	if (lookup_table_start == SQUASHFS_INVALID_BLK)
+		goto handle_fragments;
+
+handle_fragments:
+	fragments = le32_to_cpu(sblk->fragments);
+	if (fragments == 0)
+		goto check_directory_table;
+	msblk->fragment_cache = squashfs_cache_init("fragment",
+		SQUASHFS_CACHED_FRAGMENTS, msblk->block_size);
+	if (msblk->fragment_cache == NULL) {
+		err = -ENOMEM;
+		goto failed_mount;
+	}
+
+	/* Allocate and read fragment index table */
+	msblk->fragment_index = squashfs_read_fragment_index_table(sb,
+		le64_to_cpu(sblk->fragment_table_start), next_table, fragments);
+	if (IS_ERR(msblk->fragment_index)) {
+		ERROR("unable to read fragment index table\n");
+		err = PTR_ERR(msblk->fragment_index);
+		msblk->fragment_index = NULL;
+		goto failed_mount;
+	}
+	next_table = le64_to_cpu(msblk->fragment_index[0]);
+
+check_directory_table:
+	/* Sanity check directory_table */
+	if (msblk->directory_table > next_table) {
+		err = -EINVAL;
+		goto failed_mount;
+	}
+
+	/* Sanity check inode_table */
+	if (msblk->inode_table >= msblk->directory_table) {
+		err = -EINVAL;
+		goto failed_mount;
+	}
+
+	/* allocate root */
+	root = squashfs_iget(sb, root_inode, 1);
+	if (!root) {
+		err = -ENOMEM;
+		goto failed_mount;
+	}
+
+	sb->s_root = d_make_root(root);
+	if (sb->s_root == NULL) {
+		ERROR("Root inode create failed\n");
+		err = -ENOMEM;
+		goto failed_mount;
+	}
+
+	kfree(sblk);
+
+	return 0;
+
+failed_mount:
+	squashfs_cache_delete(msblk->block_cache);
+	squashfs_cache_delete(msblk->fragment_cache);
+	squashfs_cache_delete(msblk->read_page);
+	squashfs_decompressor_destroy(msblk);
+	kfree(msblk->inode_lookup_table);
+	kfree(msblk->fragment_index);
+	kfree(msblk->id_table);
+	kfree(msblk->xattr_id_table);
+	kfree(sb->s_fs_info);
+	sb->s_fs_info = NULL;
+	kfree(sblk);
+	return err;
+}
+
+
+int squashfs_mount(struct fs_device_d *fsdev, int silent)
+{
+	struct squashfs_priv *priv = fsdev->dev.priv;
+
+	dev_dbg(&fsdev->dev, "squashfs_mount\n");
+
+	if (squashfs_fill_super(&priv->sb, fsdev, silent))
+		return -EINVAL;
+
+	return 0;
+}