diff options
Diffstat (limited to 'kernel/xloop_file_fmt_qcow_main.c')
| -rw-r--r-- | kernel/xloop_file_fmt_qcow_main.c | 953 |
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"); |