If qcow2 file has only inactive bitmaps, we should not reset QCOW2_AUTOCLEAR_BITMAPS bit. Bitmaps are already allocated and we are not expected to change them. Still reset this bit if we encounter enabled bitmap.
https://virtuozzo.atlassian.net/browse/VSTOR-99404 Signed-off-by: Andrey Zhadchenko <andrey.zhadche...@virtuozzo.com> --- drivers/md/dm-qcow2-target.c | 125 ++++++++++++++++++++++++++++++++++- drivers/md/dm-qcow2.h | 42 ++++++++++++ 2 files changed, 165 insertions(+), 2 deletions(-) diff --git a/drivers/md/dm-qcow2-target.c b/drivers/md/dm-qcow2-target.c index 276eab9acc4f..9b85d79fb02c 100644 --- a/drivers/md/dm-qcow2-target.c +++ b/drivers/md/dm-qcow2-target.c @@ -555,7 +555,7 @@ static int qcow2_check_convert_hdr(struct dm_target *ti, return 0; hdr->incompatible_features = be64_to_cpu(raw_hdr->incompatible_features); - hdr->autoclear_features = be64_to_cpu(raw_hdr->autoclear_features); + hdr->autoclear_features = 0; hdr->refcount_order = be32_to_cpu(raw_hdr->refcount_order); hdr->header_length = be32_to_cpu(raw_hdr->header_length); @@ -631,7 +631,7 @@ int qcow2_set_image_file_features(struct qcow2 *qcow2, bool dirty) return -EIO; raw_hdr = kmap(md->page); - qcow2->hdr.autoclear_features = raw_hdr->autoclear_features = 0; + raw_hdr->autoclear_features = cpu_to_be64(qcow2->hdr.autoclear_features); if (kernel_sets_dirty_bit) { if (dirty) raw_hdr->incompatible_features |= dirty_mask; @@ -709,12 +709,117 @@ static int qcow2_attach_file(struct dm_target *ti, struct qcow2_target *tgt, } ALLOW_ERROR_INJECTION(qcow2_attach_file, ERRNO); +static int qcow2_parse_bitmap_ext(struct dm_target *ti, struct qcow2 *qcow2, + struct Qcow2BitmapHeaderExt *ext) +{ + struct Qcow2BitmapDirEntry entry; + u64 index, size, offset; + struct page **pages = NULL; + char *addr = NULL; + int i, ret; + bool clear_bitmaps = false; + + ext->bitmap_directory_offset = be64_to_cpu(ext->bitmap_directory_offset); + ext->bitmap_directory_size = be64_to_cpu(ext->bitmap_directory_size); + ext->nb_bitmaps = be32_to_cpu(ext->nb_bitmaps); + + if (!ext->nb_bitmaps || + ext->nb_bitmaps > QCOW2_MAX_BITMAPS || + ext->bitmap_directory_size > QCOW2_MAX_BITMAP_DIRECTORY_SIZE || + ext->bitmap_directory_offset % PAGE_SIZE) + return -EINVAL; + + index = ext->bitmap_directory_offset >> PAGE_SHIFT; + size = round_up(ext->bitmap_directory_size, PAGE_SIZE); + + addr = kvmalloc(size, GFP_KERNEL); + if (!addr) + return -ENOMEM; + + pages = kvmalloc((size / PAGE_SIZE) * sizeof(*pages), GFP_KERNEL); + if (!pages) { + ret = -ENOMEM; + goto out; + } + + for (i = 0; i < size >> PAGE_SHIFT; i++) + pages[i] = virt_to_page(addr + i * PAGE_SIZE); + + ret = qcow2_rw_pages_sync(READ, qcow2, index, pages, size >> PAGE_SHIFT); + if (ret) + goto out; + + offset = 0; + while (offset < ext->bitmap_directory_size) { + memcpy(&entry, addr + offset, sizeof(entry)); + + entry.flags = be32_to_cpu(entry.flags); + entry.name_size = be16_to_cpu(entry.name_size); + entry.extra_data_size = be32_to_cpu(entry.extra_data_size); + + if (entry.flags & BME_FLAG_AUTO) + clear_bitmaps = true; + + offset += round_up(sizeof(entry) + entry.name_size + entry.extra_data_size, 8); + } + + if (!clear_bitmaps) + qcow2->hdr.autoclear_features |= QCOW2_AUTOCLEAR_BITMAPS; + + ret = 0; +out: + kvfree(pages); + kvfree(addr); + return ret; +} + +static int qcow2_parse_extensions(struct dm_target *ti, struct qcow2 *qcow2, + loff_t start, loff_t end, void *addr) +{ + loff_t offset; + struct QCowExtension ext; + + offset = start; + while (offset < end) { + memcpy(&ext, (char *)addr + offset, sizeof(ext)); + ext.magic = be32_to_cpu(ext.magic); + ext.len = be32_to_cpu(ext.len); + offset += sizeof(ext); + + switch (ext.magic) { + case QCOW2_EXT_MAGIC_BITMAPS: + struct Qcow2BitmapHeaderExt bitmaps_ext; + + if (ext.len != sizeof(bitmaps_ext)) { + QC_ERR(ti, "dm-qcow2: unexpected bitmap extension size\n"); + return -EINVAL; + } + + memcpy(&bitmaps_ext, (char *)addr + offset, + sizeof(bitmaps_ext)); + if (qcow2_parse_bitmap_ext(ti, qcow2, &bitmaps_ext)) + return -EINVAL; + break; + case QCOW2_EXT_MAGIC_END: + return 0; + default: + /* Skip all other extensions */ + break; + } + + offset += ((ext.len + 7) & ~7); + } + + return 0; +} + static int qcow2_parse_header(struct dm_target *ti, struct qcow2 *qcow2, struct qcow2 *upper, bool is_bottom) { struct QCowHeader *raw_hdr, *hdr = &qcow2->hdr; loff_t min_len, max_len, new_size; struct file *file = qcow2->file; + loff_t ext_start, ext_end; struct md_page *md; int ret; @@ -779,6 +884,22 @@ static int qcow2_parse_header(struct dm_target *ti, struct qcow2 *qcow2, ret = -EFBIG; if (qcow2->reftable_max_file_size < qcow2->file_size) goto out; + + ext_start = hdr->header_length; + if (hdr->backing_file_offset) + ext_end = hdr->backing_file_offset; + else + ext_end = PAGE_SIZE; + + if (ext_end > PAGE_SIZE) { + QC_INFO(ti, "dm-qcow2: extensions are too long, skipping them\n"); + } else { + ret = qcow2_parse_extensions(ti, qcow2, ext_start, ext_end, raw_hdr); + if (ret) { + QC_ERR(ti, "dm-qcow2: failed to parse extensions\n"); + goto out; + } + } ret = 0; out: return ret; diff --git a/drivers/md/dm-qcow2.h b/drivers/md/dm-qcow2.h index 42f041a82a5b..d9bcbead0657 100644 --- a/drivers/md/dm-qcow2.h +++ b/drivers/md/dm-qcow2.h @@ -43,6 +43,9 @@ struct QCowHeader { #define INCOMPATIBLE_FEATURES_EXTL2_BIT (1 << 4) uint64_t incompatible_features; uint64_t compatible_features; + +#define QCOW2_AUTOCLEAR_BITMAPS (1 << 0) +#define QCOW2_AUTOCLEAR_DATA_FILE_RAW (1 << 1) uint64_t autoclear_features; uint32_t refcount_order; @@ -57,6 +60,45 @@ struct QCowHeader { uint8_t padding[7]; } __packed; +#define QCOW2_EXT_MAGIC_END 0 +#define QCOW2_EXT_MAGIC_BITMAPS 0x23852875 + +struct QCowExtension { + uint32_t magic; + uint32_t len; +} __packed; + +/* Bitmap header extension constraints */ +#define QCOW2_MAX_BITMAPS 65535 +#define QCOW2_MAX_BITMAP_DIRECTORY_SIZE (1024 * QCOW2_MAX_BITMAPS) + +struct Qcow2BitmapHeaderExt { + uint32_t nb_bitmaps; + uint32_t reserved32; + uint64_t bitmap_directory_size; + uint64_t bitmap_directory_offset; +} __packed; + +/* Bitmap directory entry flags */ +#define BME_RESERVED_FLAGS 0xfffffffcU +#define BME_FLAG_IN_USE (1U << 0) +#define BME_FLAG_AUTO (1U << 1) + +struct Qcow2BitmapDirEntry { + /* header is 8 byte aligned */ + uint64_t bitmap_table_offset; + + uint32_t bitmap_table_size; + uint32_t flags; + + uint8_t type; + uint8_t granularity_bits; + uint16_t name_size; + uint32_t extra_data_size; + /* extra data follows */ + /* name follows */ +} __packed; + struct wb_desc { struct md_page *md; #define LX_INDEXES_PER_PAGE (PAGE_SIZE / sizeof(u64)) -- 2.39.3 _______________________________________________ Devel mailing list Devel@openvz.org https://lists.openvz.org/mailman/listinfo/devel
