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Diffstat (limited to 'kernel/xloop_file_fmt_qcow_main.c')
-rw-r--r--kernel/xloop_file_fmt_qcow_main.c953
1 files changed, 953 insertions, 0 deletions
diff --git a/kernel/xloop_file_fmt_qcow_main.c b/kernel/xloop_file_fmt_qcow_main.c
new file mode 100644
index 0000000..c1fe34c
--- /dev/null
+++ b/kernel/xloop_file_fmt_qcow_main.c
@@ -0,0 +1,953 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * xloop_file_fmt_qcow.c
+ *
+ * QCOW file format driver for the xloop device module.
+ *
+ * Copyright (C) 2019 Manuel Bentele <development@manuel-bentele.de>
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/fs.h>
+#include <linux/types.h>
+#include <linux/limits.h>
+#include <linux/blkdev.h>
+#include <linux/bio.h>
+#include <linux/bvec.h>
+#include <linux/mutex.h>
+#include <linux/uio.h>
+#include <linux/string.h>
+#include <linux/vmalloc.h>
+#include <linux/zlib.h>
+
+#include "xloop_file_fmt.h"
+#include "xloop_file_fmt_qcow_main.h"
+#include "xloop_file_fmt_qcow_cache.h"
+#include "xloop_file_fmt_qcow_cluster.h"
+
+static int __qcow_file_fmt_header_read(struct file *file,
+ struct xloop_file_fmt_qcow_header *header)
+{
+ ssize_t len;
+ loff_t offset;
+ int ret = 0;
+
+ /* read QCOW header */
+ offset = 0;
+ len = kernel_read(file, header, sizeof(*header), &offset);
+ if (len < 0) {
+ printk(KERN_ERR "xloop_file_fmt_qcow: could not read QCOW "
+ "header");
+ return len;
+ }
+
+ header->magic = be32_to_cpu(header->magic);
+ header->version = be32_to_cpu(header->version);
+ header->backing_file_offset = be64_to_cpu(header->backing_file_offset);
+ header->backing_file_size = be32_to_cpu(header->backing_file_size);
+ header->cluster_bits = be32_to_cpu(header->cluster_bits);
+ header->size = be64_to_cpu(header->size);
+ header->crypt_method = be32_to_cpu(header->crypt_method);
+ header->l1_size = be32_to_cpu(header->l1_size);
+ header->l1_table_offset = be64_to_cpu(header->l1_table_offset);
+ header->refcount_table_offset =
+ be64_to_cpu(header->refcount_table_offset);
+ header->refcount_table_clusters =
+ be32_to_cpu(header->refcount_table_clusters);
+ header->nb_snapshots = be32_to_cpu(header->nb_snapshots);
+ header->snapshots_offset = be64_to_cpu(header->snapshots_offset);
+
+ /* check QCOW file format and header version */
+ if (header->magic != QCOW_MAGIC) {
+ printk(KERN_ERR "xloop_file_fmt_qcow: image is not in QCOW "
+ "format");
+ return -EINVAL;
+ }
+
+ if (header->version < 2 || header->version > 3) {
+ printk(KERN_ERR "xloop_file_fmt_qcow: unsupported QCOW version "
+ "%d", header->version);
+ return -ENOTSUPP;
+ }
+
+ /* initialize version 3 header fields */
+ if (header->version == 2) {
+ header->incompatible_features = 0;
+ header->compatible_features = 0;
+ header->autoclear_features = 0;
+ header->refcount_order = 4;
+ header->header_length = 72;
+ } else {
+ header->incompatible_features =
+ be64_to_cpu(header->incompatible_features);
+ header->compatible_features =
+ be64_to_cpu(header->compatible_features);
+ header->autoclear_features =
+ be64_to_cpu(header->autoclear_features);
+ header->refcount_order = be32_to_cpu(header->refcount_order);
+ header->header_length = be32_to_cpu(header->header_length);
+
+ if (header->header_length < 104) {
+ printk(KERN_ERR "xloop_file_fmt_qcow: QCOW header too "
+ "short");
+ return -EINVAL;
+ }
+ }
+
+ return ret;
+}
+
+static int __qcow_file_fmt_validate_table(struct xloop_file_fmt *xlo_fmt,
+ u64 offset, u64 entries, size_t entry_len, s64 max_size_bytes,
+ const char *table_name)
+{
+ struct xloop_file_fmt_qcow_data *qcow_data = xlo_fmt->private_data;
+
+ if (entries > max_size_bytes / entry_len) {
+ printk(KERN_INFO "xloop_file_fmt_qcow: %s too large",
+ table_name);
+ return -EFBIG;
+ }
+
+ /* Use signed S64_MAX as the maximum even for u64 header fields,
+ * because values will be passed to qemu functions taking s64. */
+ if ((S64_MAX - entries * entry_len < offset) || (
+ xloop_file_fmt_qcow_offset_into_cluster(qcow_data, offset) != 0)
+ ) {
+ printk(KERN_INFO "xloop_file_fmt_qcow: %s offset invalid",
+ table_name);
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static inline loff_t __qcow_file_fmt_rq_get_pos(struct xloop_file_fmt *xlo_fmt,
+ struct request *rq)
+{
+ struct xloop_device *xlo = xloop_file_fmt_get_xlo(xlo_fmt);
+ return ((loff_t) blk_rq_pos(rq) << 9) + xlo->xlo_offset;
+}
+
+static int __qcow_file_fmt_compression_init(struct xloop_file_fmt *xlo_fmt)
+{
+ struct xloop_file_fmt_qcow_data *qcow_data = xlo_fmt->private_data;
+ int ret = 0;
+
+ qcow_data->strm = kzalloc(sizeof(*qcow_data->strm), GFP_KERNEL);
+ if (!qcow_data->strm) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ qcow_data->strm->workspace = vzalloc(zlib_inflate_workspacesize());
+ if (!qcow_data->strm->workspace) {
+ ret = -ENOMEM;
+ goto out_free_strm;
+ }
+
+ qcow_data->cmp_last_coffset = ULLONG_MAX;
+ qcow_data->cmp_out_buf = vmalloc(qcow_data->cluster_size);
+ if (!qcow_data->cmp_out_buf) {
+ ret = -ENOMEM;
+ goto out_free_workspace;
+ }
+
+ return ret;
+
+out_free_workspace:
+ vfree(qcow_data->strm->workspace);
+out_free_strm:
+ kfree(qcow_data->strm);
+out:
+ return ret;
+}
+
+static void __qcow_file_fmt_compression_exit(struct xloop_file_fmt *xlo_fmt)
+{
+ struct xloop_file_fmt_qcow_data *qcow_data = xlo_fmt->private_data;
+
+ vfree(qcow_data->strm->workspace);
+ kfree(qcow_data->strm);
+ vfree(qcow_data->cmp_out_buf);
+}
+
+#ifdef CONFIG_DEBUG_FS
+static void __qcow_file_fmt_header_to_buf(struct xloop_file_fmt *xlo_fmt,
+ const struct xloop_file_fmt_qcow_header *header)
+{
+ struct xloop_file_fmt_qcow_data *qcow_data = xlo_fmt->private_data;
+ char *header_buf = qcow_data->dbgfs_file_qcow_header_buf;
+ ssize_t len = 0;
+
+ len += sprintf(header_buf + len, "magic: %d\n",
+ header->magic);
+ len += sprintf(header_buf + len, "version: %d\n",
+ header->version);
+ len += sprintf(header_buf + len, "backing_file_offset: %lld\n",
+ header->backing_file_offset);
+ len += sprintf(header_buf + len, "backing_file_size: %d\n",
+ header->backing_file_size);
+ len += sprintf(header_buf + len, "cluster_bits: %d\n",
+ header->cluster_bits);
+ len += sprintf(header_buf + len, "size: %lld\n",
+ header->size);
+ len += sprintf(header_buf + len, "crypt_method: %d\n",
+ header->crypt_method);
+ len += sprintf(header_buf + len, "l1_size: %d\n",
+ header->l1_size);
+ len += sprintf(header_buf + len, "l1_table_offset: %lld\n",
+ header->l1_table_offset);
+ len += sprintf(header_buf + len, "refcount_table_offset: %lld\n",
+ header->refcount_table_offset);
+ len += sprintf(header_buf + len, "refcount_table_clusters: %d\n",
+ header->refcount_table_clusters);
+ len += sprintf(header_buf + len, "nb_snapshots: %d\n",
+ header->nb_snapshots);
+ len += sprintf(header_buf + len, "snapshots_offset: %lld\n",
+ header->snapshots_offset);
+
+ if (header->version == 3) {
+ len += sprintf(header_buf + len,
+ "incompatible_features: %lld\n",
+ header->incompatible_features);
+ len += sprintf(header_buf + len,
+ "compatible_features: %lld\n",
+ header->compatible_features);
+ len += sprintf(header_buf + len,
+ "autoclear_features: %lld\n",
+ header->autoclear_features);
+ len += sprintf(header_buf + len,
+ "refcount_order: %d\n",
+ header->refcount_order);
+ len += sprintf(header_buf + len,
+ "header_length: %d\n",
+ header->header_length);
+ }
+
+ ASSERT(len < QCOW_HEADER_BUF_LEN);
+}
+
+static ssize_t __qcow_file_fmt_dbgfs_hdr_read(struct file *file,
+ char __user *buf, size_t size, loff_t *ppos)
+{
+ struct xloop_file_fmt *xlo_fmt = file->private_data;
+ struct xloop_file_fmt_qcow_data *qcow_data = xlo_fmt->private_data;
+ char *header_buf = qcow_data->dbgfs_file_qcow_header_buf;
+
+ return simple_read_from_buffer(buf, size, ppos, header_buf,
+ strlen(header_buf));
+}
+
+static const struct file_operations qcow_file_fmt_dbgfs_hdr_fops = {
+ .open = simple_open,
+ .read = __qcow_file_fmt_dbgfs_hdr_read
+};
+
+static ssize_t __qcow_file_fmt_dbgfs_ofs_read(struct file *file,
+ char __user *buf, size_t size, loff_t *ppos)
+{
+ struct xloop_file_fmt *xlo_fmt = file->private_data;
+ struct xloop_file_fmt_qcow_data *qcow_data = xlo_fmt->private_data;
+ unsigned int cur_bytes = 1;
+ u64 offset = 0;
+ u64 cluster_offset = 0;
+ s64 offset_in_cluster = 0;
+ ssize_t len = 0;
+ int ret = 0;
+
+ /* read the share debugfs offset */
+ ret = mutex_lock_interruptible(&qcow_data->dbgfs_qcow_offset_mutex);
+ if (ret)
+ return ret;
+
+ offset = qcow_data->dbgfs_qcow_offset;
+ mutex_unlock(&qcow_data->dbgfs_qcow_offset_mutex);
+
+ /* calculate and print the cluster offset */
+ ret = xloop_file_fmt_qcow_cluster_get_offset(xlo_fmt,
+ offset, &cur_bytes, &cluster_offset);
+ if (ret < 0)
+ return -EINVAL;
+
+ offset_in_cluster = xloop_file_fmt_qcow_offset_into_cluster(qcow_data,
+ offset);
+
+ len = sprintf(qcow_data->dbgfs_file_qcow_cluster_buf,
+ "offset: %lld\ncluster_offset: %lld\noffset_in_cluster: %lld\n",
+ offset, cluster_offset, offset_in_cluster);
+
+ ASSERT(len < QCOW_CLUSTER_BUF_LEN);
+
+ return simple_read_from_buffer(buf, size, ppos,
+ qcow_data->dbgfs_file_qcow_cluster_buf, len);
+}
+
+static ssize_t __qcow_file_fmt_dbgfs_ofs_write(struct file *file,
+ const char __user *buf, size_t size, loff_t *ppos)
+{
+ struct xloop_file_fmt *xlo_fmt = file->private_data;
+ struct xloop_file_fmt_qcow_data *qcow_data = xlo_fmt->private_data;
+ ssize_t len = 0;
+ int ret = 0;
+
+ if (*ppos > QCOW_OFFSET_BUF_LEN || size > QCOW_OFFSET_BUF_LEN)
+ return -EINVAL;
+
+ len = simple_write_to_buffer(qcow_data->dbgfs_file_qcow_offset_buf,
+ QCOW_OFFSET_BUF_LEN, ppos, buf, size);
+ if (len < 0)
+ return len;
+
+ qcow_data->dbgfs_file_qcow_offset_buf[len] = '\0';
+
+ ret = mutex_lock_interruptible(&qcow_data->dbgfs_qcow_offset_mutex);
+ if (ret)
+ return ret;
+
+ ret = kstrtou64(qcow_data->dbgfs_file_qcow_offset_buf, 10,
+ &qcow_data->dbgfs_qcow_offset);
+ if (ret < 0)
+ goto out;
+
+ ret = len;
+out:
+ mutex_unlock(&qcow_data->dbgfs_qcow_offset_mutex);
+ return ret;
+}
+
+static const struct file_operations qcow_file_fmt_dbgfs_ofs_fops = {
+ .open = simple_open,
+ .read = __qcow_file_fmt_dbgfs_ofs_read,
+ .write = __qcow_file_fmt_dbgfs_ofs_write
+};
+
+static int __qcow_file_fmt_dbgfs_init(struct xloop_file_fmt *xlo_fmt)
+{
+ struct xloop_file_fmt_qcow_data *qcow_data = xlo_fmt->private_data;
+ struct xloop_device *xlo = xloop_file_fmt_get_xlo(xlo_fmt);
+ int ret = 0;
+
+ qcow_data->dbgfs_dir = debugfs_create_dir("QCOW", xlo->xlo_dbgfs_dir);
+ if (IS_ERR_OR_NULL(qcow_data->dbgfs_dir)) {
+ ret = -ENODEV;
+ goto out;
+ }
+
+ qcow_data->dbgfs_file_qcow_header = debugfs_create_file("header",
+ S_IRUGO, qcow_data->dbgfs_dir, xlo_fmt,
+ &qcow_file_fmt_dbgfs_hdr_fops);
+ if (IS_ERR_OR_NULL(qcow_data->dbgfs_file_qcow_header)) {
+ ret = -ENODEV;
+ goto out_free_dbgfs_dir;
+ }
+
+ qcow_data->dbgfs_file_qcow_offset = debugfs_create_file("offset",
+ S_IRUGO | S_IWUSR, qcow_data->dbgfs_dir, xlo_fmt,
+ &qcow_file_fmt_dbgfs_ofs_fops);
+ if (IS_ERR_OR_NULL(qcow_data->dbgfs_file_qcow_offset)) {
+ qcow_data->dbgfs_file_qcow_offset = NULL;
+ ret = -ENODEV;
+ goto out_free_dbgfs_hdr;
+ }
+
+ qcow_data->dbgfs_qcow_offset = 0;
+ mutex_init(&qcow_data->dbgfs_qcow_offset_mutex);
+
+ return ret;
+
+out_free_dbgfs_hdr:
+ debugfs_remove(qcow_data->dbgfs_file_qcow_header);
+ qcow_data->dbgfs_file_qcow_header = NULL;
+out_free_dbgfs_dir:
+ debugfs_remove(qcow_data->dbgfs_dir);
+ qcow_data->dbgfs_dir = NULL;
+out:
+ return ret;
+}
+
+static void __qcow_file_fmt_dbgfs_exit(struct xloop_file_fmt *xlo_fmt)
+{
+ struct xloop_file_fmt_qcow_data *qcow_data = xlo_fmt->private_data;
+
+ if (qcow_data->dbgfs_file_qcow_offset)
+ debugfs_remove(qcow_data->dbgfs_file_qcow_offset);
+
+ mutex_destroy(&qcow_data->dbgfs_qcow_offset_mutex);
+
+ if (qcow_data->dbgfs_file_qcow_header)
+ debugfs_remove(qcow_data->dbgfs_file_qcow_header);
+
+ if (qcow_data->dbgfs_dir)
+ debugfs_remove(qcow_data->dbgfs_dir);
+}
+#endif
+
+static int qcow_file_fmt_init(struct xloop_file_fmt *xlo_fmt)
+{
+ struct xloop_file_fmt_qcow_data *qcow_data;
+ struct xloop_device *xlo = xloop_file_fmt_get_xlo(xlo_fmt);
+ struct xloop_file_fmt_qcow_header header;
+ u64 l1_vm_state_index;
+ u64 l2_cache_size;
+ u64 l2_cache_entry_size;
+ ssize_t len;
+ unsigned int i;
+ int ret = 0;
+
+ /* allocate memory for saving QCOW file format data */
+ qcow_data = kzalloc(sizeof(*qcow_data), GFP_KERNEL);
+ if (!qcow_data)
+ return -ENOMEM;
+
+ xlo_fmt->private_data = qcow_data;
+
+ /* read the QCOW file header */
+ ret = __qcow_file_fmt_header_read(xlo->xlo_backing_file, &header);
+ if (ret)
+ goto free_qcow_data;
+
+ /* save information of the header fields in human readable format in
+ * a file buffer to access it with debugfs */
+#ifdef CONFIG_DEBUG_FS
+ __qcow_file_fmt_header_to_buf(xlo_fmt, &header);
+#endif
+
+ qcow_data->qcow_version = header.version;
+
+ /* Initialise cluster size */
+ if (header.cluster_bits < QCOW_MIN_CLUSTER_BITS
+ || header.cluster_bits > QCOW_MAX_CLUSTER_BITS) {
+ printk(KERN_ERR "xloop_file_fmt_qcow: unsupported cluster "
+ "size: 2^%d", header.cluster_bits);
+ ret = -EINVAL;
+ goto free_qcow_data;
+ }
+
+ qcow_data->cluster_bits = header.cluster_bits;
+ qcow_data->cluster_size = 1 << qcow_data->cluster_bits;
+ qcow_data->cluster_sectors = 1 <<
+ (qcow_data->cluster_bits - SECTOR_SHIFT);
+
+ if (header.header_length > qcow_data->cluster_size) {
+ printk(KERN_ERR "xloop_file_fmt_qcow: QCOW header exceeds "
+ "cluster size");
+ ret = -EINVAL;
+ goto free_qcow_data;
+ }
+
+ if (header.backing_file_offset > qcow_data->cluster_size) {
+ printk(KERN_ERR "xloop_file_fmt_qcow: invalid backing file "
+ "offset");
+ ret = -EINVAL;
+ goto free_qcow_data;
+ }
+
+ if (header.backing_file_offset) {
+ printk(KERN_ERR "xloop_file_fmt_qcow: backing file support not "
+ "available");
+ ret = -ENOTSUPP;
+ goto free_qcow_data;
+ }
+
+ /* handle feature bits */
+ qcow_data->incompatible_features = header.incompatible_features;
+ qcow_data->compatible_features = header.compatible_features;
+ qcow_data->autoclear_features = header.autoclear_features;
+
+ if (qcow_data->incompatible_features & QCOW_INCOMPAT_DIRTY) {
+ printk(KERN_ERR "xloop_file_fmt_qcow: image contains "
+ "inconsistent refcounts");
+ ret = -EACCES;
+ goto free_qcow_data;
+ }
+
+ if (qcow_data->incompatible_features & QCOW_INCOMPAT_CORRUPT) {
+ printk(KERN_ERR "xloop_file_fmt_qcow: image is corrupt; cannot "
+ "be opened read/write");
+ ret = -EACCES;
+ goto free_qcow_data;
+ }
+
+ if (qcow_data->incompatible_features & QCOW_INCOMPAT_DATA_FILE) {
+ printk(KERN_ERR "xloop_file_fmt_qcow: clusters in the external "
+ "data file are not refcounted");
+ ret = -EACCES;
+ goto free_qcow_data;
+ }
+
+ /* Check support for various header values */
+ if (header.refcount_order > 6) {
+ printk(KERN_ERR "xloop_file_fmt_qcow: reference count entry "
+ "width too large; may not exceed 64 bits");
+ ret = -EINVAL;
+ goto free_qcow_data;
+ }
+ qcow_data->refcount_order = header.refcount_order;
+ qcow_data->refcount_bits = 1 << qcow_data->refcount_order;
+ qcow_data->refcount_max = U64_C(1) << (qcow_data->refcount_bits - 1);
+ qcow_data->refcount_max += qcow_data->refcount_max - 1;
+
+ qcow_data->crypt_method_header = header.crypt_method;
+ if (qcow_data->crypt_method_header) {
+ printk(KERN_ERR "xloop_file_fmt_qcow: encryption support not "
+ "available");
+ ret = -ENOTSUPP;
+ goto free_qcow_data;
+ }
+
+ /* L2 is always one cluster */
+ qcow_data->l2_bits = qcow_data->cluster_bits - 3;
+ qcow_data->l2_size = 1 << qcow_data->l2_bits;
+ /* 2^(qcow_data->refcount_order - 3) is the refcount width in bytes */
+ qcow_data->refcount_block_bits = qcow_data->cluster_bits -
+ (qcow_data->refcount_order - 3);
+ qcow_data->refcount_block_size = 1 << qcow_data->refcount_block_bits;
+ qcow_data->size = header.size;
+ qcow_data->csize_shift = (62 - (qcow_data->cluster_bits - 8));
+ qcow_data->csize_mask = (1 << (qcow_data->cluster_bits - 8)) - 1;
+ qcow_data->cluster_offset_mask = (1LL << qcow_data->csize_shift) - 1;
+
+ qcow_data->refcount_table_offset = header.refcount_table_offset;
+ qcow_data->refcount_table_size = header.refcount_table_clusters <<
+ (qcow_data->cluster_bits - 3);
+
+ if (header.refcount_table_clusters == 0) {
+ printk(KERN_ERR "xloop_file_fmt_qcow: image does not contain a "
+ "reference count table");
+ ret = -EINVAL;
+ goto free_qcow_data;
+ }
+
+ ret = __qcow_file_fmt_validate_table(xlo_fmt,
+ qcow_data->refcount_table_offset,
+ header.refcount_table_clusters, qcow_data->cluster_size,
+ QCOW_MAX_REFTABLE_SIZE, "Reference count table");
+ if (ret < 0) {
+ goto free_qcow_data;
+ }
+
+ /* The total size in bytes of the snapshot table is checked in
+ * qcow2_read_snapshots() because the size of each snapshot is
+ * variable and we don't know it yet.
+ * Here we only check the offset and number of snapshots. */
+ ret = __qcow_file_fmt_validate_table(xlo_fmt, header.snapshots_offset,
+ header.nb_snapshots,
+ sizeof(struct xloop_file_fmt_qcow_snapshot_header),
+ sizeof(struct xloop_file_fmt_qcow_snapshot_header) *
+ QCOW_MAX_SNAPSHOTS, "Snapshot table");
+ if (ret < 0) {
+ goto free_qcow_data;
+ }
+
+ /* read the level 1 table */
+ ret = __qcow_file_fmt_validate_table(xlo_fmt, header.l1_table_offset,
+ header.l1_size, sizeof(u64), QCOW_MAX_L1_SIZE,
+ "Active L1 table");
+ if (ret < 0) {
+ goto free_qcow_data;
+ }
+ qcow_data->l1_size = header.l1_size;
+ qcow_data->l1_table_offset = header.l1_table_offset;
+
+ l1_vm_state_index = xloop_file_fmt_qcow_size_to_l1(qcow_data,
+ header.size);
+ if (l1_vm_state_index > INT_MAX) {
+ printk(KERN_ERR "xloop_file_fmt_qcow: image is too big");
+ ret = -EFBIG;
+ goto free_qcow_data;
+ }
+ qcow_data->l1_vm_state_index = l1_vm_state_index;
+
+ /* the L1 table must contain at least enough entries to put header.size
+ * bytes */
+ if (qcow_data->l1_size < qcow_data->l1_vm_state_index) {
+ printk(KERN_ERR "xloop_file_fmt_qcow: L1 table is too small");
+ ret = -EINVAL;
+ goto free_qcow_data;
+ }
+
+ if (qcow_data->l1_size > 0) {
+ qcow_data->l1_table = vzalloc(round_up(qcow_data->l1_size *
+ sizeof(u64), 512));
+ if (qcow_data->l1_table == NULL) {
+ printk(KERN_ERR "xloop_file_fmt_qcow: could not "
+ "allocate L1 table");
+ ret = -ENOMEM;
+ goto free_qcow_data;
+ }
+ len = kernel_read(xlo->xlo_backing_file, qcow_data->l1_table,
+ qcow_data->l1_size * sizeof(u64),
+ &qcow_data->l1_table_offset);
+ if (len < 0) {
+ printk(KERN_ERR "xloop_file_fmt_qcow: could not read L1 "
+ "table");
+ ret = len;
+ goto free_l1_table;
+ }
+ for (i = 0; i < qcow_data->l1_size; i++) {
+ qcow_data->l1_table[i] =
+ be64_to_cpu(qcow_data->l1_table[i]);
+ }
+ }
+
+ /* Internal snapshots */
+ qcow_data->snapshots_offset = header.snapshots_offset;
+ qcow_data->nb_snapshots = header.nb_snapshots;
+
+ if (qcow_data->nb_snapshots > 0) {
+ printk(KERN_ERR "xloop_file_fmt_qcow: snapshots support not "
+ "available");
+ ret = -ENOTSUPP;
+ goto free_l1_table;
+ }
+
+
+ /* create cache for L2 */
+ l2_cache_size = qcow_data->size / (qcow_data->cluster_size / 8);
+ l2_cache_entry_size = min(qcow_data->cluster_size, (int)4096);
+
+ /* limit the L2 size to maximum QCOW_DEFAULT_L2_CACHE_MAX_SIZE */
+ l2_cache_size = min(l2_cache_size, (u64)QCOW_DEFAULT_L2_CACHE_MAX_SIZE);
+
+ /* calculate the number of cache tables */
+ l2_cache_size /= l2_cache_entry_size;
+ if (l2_cache_size < QCOW_MIN_L2_CACHE_SIZE) {
+ l2_cache_size = QCOW_MIN_L2_CACHE_SIZE;
+ }
+
+ if (l2_cache_size > INT_MAX) {
+ printk(KERN_ERR "xloop_file_fmt_qcow: L2 cache size too big");
+ ret = -EINVAL;
+ goto free_l1_table;
+ }
+
+ qcow_data->l2_slice_size = l2_cache_entry_size / sizeof(u64);
+
+ qcow_data->l2_table_cache = xloop_file_fmt_qcow_cache_create(xlo_fmt,
+ l2_cache_size, l2_cache_entry_size);
+ if (!qcow_data->l2_table_cache) {
+ ret = -ENOMEM;
+ goto free_l1_table;
+ }
+
+ /* initialize compression support */
+ ret = __qcow_file_fmt_compression_init(xlo_fmt);
+ if (ret < 0)
+ goto free_l2_cache;
+
+ /* initialize debugfs entries */
+#ifdef CONFIG_DEBUG_FS
+ ret = __qcow_file_fmt_dbgfs_init(xlo_fmt);
+ if (ret < 0)
+ goto free_l2_cache;
+#endif
+
+ return ret;
+
+free_l2_cache:
+ xloop_file_fmt_qcow_cache_destroy(xlo_fmt);
+free_l1_table:
+ vfree(qcow_data->l1_table);
+free_qcow_data:
+ kfree(qcow_data);
+ xlo_fmt->private_data = NULL;
+ return ret;
+}
+
+static void qcow_file_fmt_exit(struct xloop_file_fmt *xlo_fmt)
+{
+ struct xloop_file_fmt_qcow_data *qcow_data = xlo_fmt->private_data;
+
+#ifdef CONFIG_DEBUG_FS
+ __qcow_file_fmt_dbgfs_exit(xlo_fmt);
+#endif
+
+ __qcow_file_fmt_compression_exit(xlo_fmt);
+
+ if (qcow_data->l1_table) {
+ vfree(qcow_data->l1_table);
+ }
+
+ if (qcow_data->l2_table_cache) {
+ xloop_file_fmt_qcow_cache_destroy(xlo_fmt);
+ }
+
+ if (qcow_data) {
+ kfree(qcow_data);
+ xlo_fmt->private_data = NULL;
+ }
+}
+
+static ssize_t __qcow_file_fmt_buffer_decompress(struct xloop_file_fmt *xlo_fmt,
+ void *dest,
+ size_t dest_size,
+ const void *src,
+ size_t src_size)
+{
+ struct xloop_file_fmt_qcow_data *qcow_data = xlo_fmt->private_data;
+ int ret = 0;
+
+ qcow_data->strm->avail_in = src_size;
+ qcow_data->strm->next_in = (void *) src;
+ qcow_data->strm->avail_out = dest_size;
+ qcow_data->strm->next_out = dest;
+
+ ret = zlib_inflateInit2(qcow_data->strm, -12);
+ if (ret != Z_OK) {
+ return -1;
+ }
+
+ ret = zlib_inflate(qcow_data->strm, Z_FINISH);
+ if ((ret != Z_STREAM_END && ret != Z_BUF_ERROR)
+ || qcow_data->strm->avail_out != 0) {
+ /* We approve Z_BUF_ERROR because we need @dest buffer to be
+ * filled, but @src buffer may be processed partly (because in
+ * qcow2 we know size of compressed data with precision of one
+ * sector) */
+ ret = -1;
+ } else {
+ ret = 0;
+ }
+ return ret;
+}
+
+static int __qcow_file_fmt_read_compressed(struct xloop_file_fmt *xlo_fmt,
+ struct bio_vec *bvec,
+ u64 file_cluster_offset,
+ u64 offset,
+ u64 bytes,
+ u64 bytes_done)
+{
+ struct xloop_file_fmt_qcow_data *qcow_data = xlo_fmt->private_data;
+ struct xloop_device *xlo = xloop_file_fmt_get_xlo(xlo_fmt);
+ int ret = 0, csize, nb_csectors;
+ u64 coffset;
+ u8 *in_buf = NULL;
+ ssize_t len;
+ void *data;
+ unsigned long irq_flags;
+ int offset_in_cluster = xloop_file_fmt_qcow_offset_into_cluster(
+ qcow_data, offset);
+
+ coffset = file_cluster_offset & qcow_data->cluster_offset_mask;
+ nb_csectors = ((file_cluster_offset >> qcow_data->csize_shift) &
+ qcow_data->csize_mask) + 1;
+ csize = nb_csectors * QCOW_COMPRESSED_SECTOR_SIZE -
+ (coffset & ~QCOW_COMPRESSED_SECTOR_MASK);
+
+
+ if (qcow_data->cmp_last_coffset != coffset) {
+ in_buf = vmalloc(csize);
+ if (!in_buf) {
+ qcow_data->cmp_last_coffset = ULLONG_MAX;
+ return -ENOMEM;
+ }
+ qcow_data->cmp_last_coffset = coffset;
+ len = kernel_read(xlo->xlo_backing_file, in_buf, csize, &coffset);
+ if (len < 0) {
+ qcow_data->cmp_last_coffset = ULLONG_MAX;
+ ret = len;
+ goto out_free_in_buf;
+ }
+
+ if (__qcow_file_fmt_buffer_decompress(xlo_fmt, qcow_data->cmp_out_buf,
+ qcow_data->cluster_size, in_buf, csize) < 0) {
+ qcow_data->cmp_last_coffset = ULLONG_MAX;
+ ret = -EIO;
+ goto out_free_in_buf;
+ }
+ }
+
+ ASSERT(bytes <= bvec->bv_len);
+ data = bvec_kmap_irq(bvec, &irq_flags) + bytes_done;
+ memcpy(data, qcow_data->cmp_out_buf + offset_in_cluster, bytes);
+ flush_dcache_page(bvec->bv_page);
+ bvec_kunmap_irq(data, &irq_flags);
+
+out_free_in_buf:
+ vfree(in_buf);
+
+ return ret;
+}
+
+static int __qcow_file_fmt_read_bvec(struct xloop_file_fmt *xlo_fmt,
+ struct bio_vec *bvec,
+ loff_t *ppos)
+{
+ struct xloop_file_fmt_qcow_data *qcow_data = xlo_fmt->private_data;
+ struct xloop_device *xlo = xloop_file_fmt_get_xlo(xlo_fmt);
+ int offset_in_cluster;
+ int ret;
+ unsigned int cur_bytes; /* number of bytes in current iteration */
+ u64 bytes;
+ u64 cluster_offset = 0;
+ u64 bytes_done = 0;
+ void *data;
+ unsigned long irq_flags;
+ ssize_t len;
+ loff_t pos_read;
+
+ bytes = bvec->bv_len;
+
+ while (bytes != 0) {
+
+ /* prepare next request */
+ cur_bytes = bytes;
+
+ ret = xloop_file_fmt_qcow_cluster_get_offset(xlo_fmt, *ppos,
+ &cur_bytes, &cluster_offset);
+ if (ret < 0) {
+ goto fail;
+ }
+
+ offset_in_cluster = xloop_file_fmt_qcow_offset_into_cluster(
+ qcow_data, *ppos);
+
+ switch (ret) {
+ case QCOW_CLUSTER_UNALLOCATED:
+ case QCOW_CLUSTER_ZERO_PLAIN:
+ case QCOW_CLUSTER_ZERO_ALLOC:
+ data = bvec_kmap_irq(bvec, &irq_flags) + bytes_done;
+ memset(data, 0, cur_bytes);
+ flush_dcache_page(bvec->bv_page);
+ bvec_kunmap_irq(data, &irq_flags);
+ break;
+
+ case QCOW_CLUSTER_COMPRESSED:
+ ret = __qcow_file_fmt_read_compressed(xlo_fmt, bvec,
+ cluster_offset, *ppos, cur_bytes, bytes_done);
+ if (ret < 0) {
+ goto fail;
+ }
+
+ break;
+
+ case QCOW_CLUSTER_NORMAL:
+ if ((cluster_offset & 511) != 0) {
+ ret = -EIO;
+ goto fail;
+ }
+
+ pos_read = cluster_offset + offset_in_cluster;
+
+ data = bvec_kmap_irq(bvec, &irq_flags) + bytes_done;
+ len = kernel_read(xlo->xlo_backing_file, data, cur_bytes,
+ &pos_read);
+ flush_dcache_page(bvec->bv_page);
+ bvec_kunmap_irq(data, &irq_flags);
+
+ if (len < 0)
+ return len;
+
+ break;
+
+ default:
+ ret = -EIO;
+ goto fail;
+ }
+
+ bytes -= cur_bytes;
+ *ppos += cur_bytes;
+ bytes_done += cur_bytes;
+ }
+
+ ret = 0;
+
+fail:
+ return ret;
+}
+
+static int qcow_file_fmt_read(struct xloop_file_fmt *xlo_fmt,
+ struct request *rq)
+{
+ struct bio_vec bvec;
+ struct req_iterator iter;
+ loff_t pos;
+ int ret = 0;
+
+ pos = __qcow_file_fmt_rq_get_pos(xlo_fmt, rq);
+
+ rq_for_each_segment(bvec, rq, iter) {
+ ret = __qcow_file_fmt_read_bvec(xlo_fmt, &bvec, &pos);
+ if (ret)
+ return ret;
+
+ cond_resched();
+ }
+
+ return ret;
+}
+
+static loff_t qcow_file_fmt_sector_size(struct xloop_file_fmt *xlo_fmt,
+ struct file *file, loff_t offset, loff_t sizelimit)
+{
+ struct xloop_file_fmt_qcow_header header;
+ loff_t xloopsize;
+ int ret;
+
+ /* temporary read the QCOW file header of other QCOW image file */
+ ret = __qcow_file_fmt_header_read(file, &header);
+ if (ret)
+ return 0;
+
+ /* compute xloopsize in bytes */
+ xloopsize = header.size;
+ if (offset > 0)
+ xloopsize -= offset;
+ /* offset is beyond i_size, weird but possible */
+ if (xloopsize < 0)
+ return 0;
+
+ if (sizelimit > 0 && sizelimit < xloopsize)
+ xloopsize = sizelimit;
+ /*
+ * Unfortunately, if we want to do I/O on the device,
+ * the number of 512-byte sectors has to fit into a sector_t.
+ */
+ return xloopsize >> 9;
+}
+
+static struct xloop_file_fmt_ops qcow_file_fmt_ops = {
+ .init = qcow_file_fmt_init,
+ .exit = qcow_file_fmt_exit,
+ .read = qcow_file_fmt_read,
+ .write = NULL,
+ .read_aio = NULL,
+ .write_aio = NULL,
+ .write_zeros = NULL,
+ .discard = NULL,
+ .flush = NULL,
+ .sector_size = qcow_file_fmt_sector_size,
+};
+
+static struct xloop_file_fmt_driver qcow_file_fmt_driver = {
+ .name = "QCOW",
+ .file_fmt_type = XLO_FILE_FMT_QCOW,
+ .ops = &qcow_file_fmt_ops,
+ .owner = THIS_MODULE,
+};
+
+static int __init xloop_file_fmt_qcow_init(void)
+{
+ printk(KERN_INFO "xloop_file_fmt_qcow: init xloop device QCOW file "
+ "format driver");
+ return xloop_file_fmt_register_driver(&qcow_file_fmt_driver);
+}
+
+static void __exit xloop_file_fmt_qcow_exit(void)
+{
+ printk(KERN_INFO "xloop_file_fmt_qcow: exit xloop device QCOW file "
+ "format driver");
+ xloop_file_fmt_unregister_driver(&qcow_file_fmt_driver);
+}
+
+module_init(xloop_file_fmt_qcow_init);
+module_exit(xloop_file_fmt_qcow_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Manuel Bentele <development@manuel-bentele.de>");
+MODULE_DESCRIPTION("xloop device QCOW file format driver");
+MODULE_SOFTDEP("pre: xloop");