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Diffstat (limited to 'contrib/qemu/block/qed.h')
| -rw-r--r-- | contrib/qemu/block/qed.h | 344 |
1 files changed, 0 insertions, 344 deletions
diff --git a/contrib/qemu/block/qed.h b/contrib/qemu/block/qed.h deleted file mode 100644 index 2b4ddedf313..00000000000 --- a/contrib/qemu/block/qed.h +++ /dev/null @@ -1,344 +0,0 @@ -/* - * QEMU Enhanced Disk Format - * - * Copyright IBM, Corp. 2010 - * - * Authors: - * Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> - * Anthony Liguori <aliguori@us.ibm.com> - * - * This work is licensed under the terms of the GNU LGPL, version 2 or later. - * See the COPYING.LIB file in the top-level directory. - * - */ - -#ifndef BLOCK_QED_H -#define BLOCK_QED_H - -#include "block/block_int.h" - -/* The layout of a QED file is as follows: - * - * +--------+----------+----------+----------+-----+ - * | header | L1 table | cluster0 | cluster1 | ... | - * +--------+----------+----------+----------+-----+ - * - * There is a 2-level pagetable for cluster allocation: - * - * +----------+ - * | L1 table | - * +----------+ - * ,------' | '------. - * +----------+ | +----------+ - * | L2 table | ... | L2 table | - * +----------+ +----------+ - * ,------' | '------. - * +----------+ | +----------+ - * | Data | ... | Data | - * +----------+ +----------+ - * - * The L1 table is fixed size and always present. L2 tables are allocated on - * demand. The L1 table size determines the maximum possible image size; it - * can be influenced using the cluster_size and table_size values. - * - * All fields are little-endian on disk. - */ - -enum { - QED_MAGIC = 'Q' | 'E' << 8 | 'D' << 16 | '\0' << 24, - - /* The image supports a backing file */ - QED_F_BACKING_FILE = 0x01, - - /* The image needs a consistency check before use */ - QED_F_NEED_CHECK = 0x02, - - /* The backing file format must not be probed, treat as raw image */ - QED_F_BACKING_FORMAT_NO_PROBE = 0x04, - - /* Feature bits must be used when the on-disk format changes */ - QED_FEATURE_MASK = QED_F_BACKING_FILE | /* supported feature bits */ - QED_F_NEED_CHECK | - QED_F_BACKING_FORMAT_NO_PROBE, - QED_COMPAT_FEATURE_MASK = 0, /* supported compat feature bits */ - QED_AUTOCLEAR_FEATURE_MASK = 0, /* supported autoclear feature bits */ - - /* Data is stored in groups of sectors called clusters. Cluster size must - * be large to avoid keeping too much metadata. I/O requests that have - * sub-cluster size will require read-modify-write. - */ - QED_MIN_CLUSTER_SIZE = 4 * 1024, /* in bytes */ - QED_MAX_CLUSTER_SIZE = 64 * 1024 * 1024, - QED_DEFAULT_CLUSTER_SIZE = 64 * 1024, - - /* Allocated clusters are tracked using a 2-level pagetable. Table size is - * a multiple of clusters so large maximum image sizes can be supported - * without jacking up the cluster size too much. - */ - QED_MIN_TABLE_SIZE = 1, /* in clusters */ - QED_MAX_TABLE_SIZE = 16, - QED_DEFAULT_TABLE_SIZE = 4, - - /* Delay to flush and clean image after last allocating write completes */ - QED_NEED_CHECK_TIMEOUT = 5, /* in seconds */ -}; - -typedef struct { - uint32_t magic; /* QED\0 */ - - uint32_t cluster_size; /* in bytes */ - uint32_t table_size; /* for L1 and L2 tables, in clusters */ - uint32_t header_size; /* in clusters */ - - uint64_t features; /* format feature bits */ - uint64_t compat_features; /* compatible feature bits */ - uint64_t autoclear_features; /* self-resetting feature bits */ - - uint64_t l1_table_offset; /* in bytes */ - uint64_t image_size; /* total logical image size, in bytes */ - - /* if (features & QED_F_BACKING_FILE) */ - uint32_t backing_filename_offset; /* in bytes from start of header */ - uint32_t backing_filename_size; /* in bytes */ -} QEDHeader; - -typedef struct { - uint64_t offsets[0]; /* in bytes */ -} QEDTable; - -/* The L2 cache is a simple write-through cache for L2 structures */ -typedef struct CachedL2Table { - QEDTable *table; - uint64_t offset; /* offset=0 indicates an invalidate entry */ - QTAILQ_ENTRY(CachedL2Table) node; - int ref; -} CachedL2Table; - -typedef struct { - QTAILQ_HEAD(, CachedL2Table) entries; - unsigned int n_entries; -} L2TableCache; - -typedef struct QEDRequest { - CachedL2Table *l2_table; -} QEDRequest; - -enum { - QED_AIOCB_WRITE = 0x0001, /* read or write? */ - QED_AIOCB_ZERO = 0x0002, /* zero write, used with QED_AIOCB_WRITE */ -}; - -typedef struct QEDAIOCB { - BlockDriverAIOCB common; - QEMUBH *bh; - int bh_ret; /* final return status for completion bh */ - QSIMPLEQ_ENTRY(QEDAIOCB) next; /* next request */ - int flags; /* QED_AIOCB_* bits ORed together */ - bool *finished; /* signal for cancel completion */ - uint64_t end_pos; /* request end on block device, in bytes */ - - /* User scatter-gather list */ - QEMUIOVector *qiov; - size_t qiov_offset; /* byte count already processed */ - - /* Current cluster scatter-gather list */ - QEMUIOVector cur_qiov; - uint64_t cur_pos; /* position on block device, in bytes */ - uint64_t cur_cluster; /* cluster offset in image file */ - unsigned int cur_nclusters; /* number of clusters being accessed */ - int find_cluster_ret; /* used for L1/L2 update */ - - QEDRequest request; -} QEDAIOCB; - -typedef struct { - BlockDriverState *bs; /* device */ - uint64_t file_size; /* length of image file, in bytes */ - - QEDHeader header; /* always cpu-endian */ - QEDTable *l1_table; - L2TableCache l2_cache; /* l2 table cache */ - uint32_t table_nelems; - uint32_t l1_shift; - uint32_t l2_shift; - uint32_t l2_mask; - - /* Allocating write request queue */ - QSIMPLEQ_HEAD(, QEDAIOCB) allocating_write_reqs; - bool allocating_write_reqs_plugged; - - /* Periodic flush and clear need check flag */ - QEMUTimer *need_check_timer; -} BDRVQEDState; - -enum { - QED_CLUSTER_FOUND, /* cluster found */ - QED_CLUSTER_ZERO, /* zero cluster found */ - QED_CLUSTER_L2, /* cluster missing in L2 */ - QED_CLUSTER_L1, /* cluster missing in L1 */ -}; - -/** - * qed_find_cluster() completion callback - * - * @opaque: User data for completion callback - * @ret: QED_CLUSTER_FOUND Success - * QED_CLUSTER_L2 Data cluster unallocated in L2 - * QED_CLUSTER_L1 L2 unallocated in L1 - * -errno POSIX error occurred - * @offset: Data cluster offset - * @len: Contiguous bytes starting from cluster offset - * - * This function is invoked when qed_find_cluster() completes. - * - * On success ret is QED_CLUSTER_FOUND and offset/len are a contiguous range - * in the image file. - * - * On failure ret is QED_CLUSTER_L2 or QED_CLUSTER_L1 for missing L2 or L1 - * table offset, respectively. len is number of contiguous unallocated bytes. - */ -typedef void QEDFindClusterFunc(void *opaque, int ret, uint64_t offset, size_t len); - -/** - * Generic callback for chaining async callbacks - */ -typedef struct { - BlockDriverCompletionFunc *cb; - void *opaque; -} GenericCB; - -void *gencb_alloc(size_t len, BlockDriverCompletionFunc *cb, void *opaque); -void gencb_complete(void *opaque, int ret); - -/** - * Header functions - */ -int qed_write_header_sync(BDRVQEDState *s); - -/** - * L2 cache functions - */ -void qed_init_l2_cache(L2TableCache *l2_cache); -void qed_free_l2_cache(L2TableCache *l2_cache); -CachedL2Table *qed_alloc_l2_cache_entry(L2TableCache *l2_cache); -void qed_unref_l2_cache_entry(CachedL2Table *entry); -CachedL2Table *qed_find_l2_cache_entry(L2TableCache *l2_cache, uint64_t offset); -void qed_commit_l2_cache_entry(L2TableCache *l2_cache, CachedL2Table *l2_table); - -/** - * Table I/O functions - */ -int qed_read_l1_table_sync(BDRVQEDState *s); -void qed_write_l1_table(BDRVQEDState *s, unsigned int index, unsigned int n, - BlockDriverCompletionFunc *cb, void *opaque); -int qed_write_l1_table_sync(BDRVQEDState *s, unsigned int index, - unsigned int n); -int qed_read_l2_table_sync(BDRVQEDState *s, QEDRequest *request, - uint64_t offset); -void qed_read_l2_table(BDRVQEDState *s, QEDRequest *request, uint64_t offset, - BlockDriverCompletionFunc *cb, void *opaque); -void qed_write_l2_table(BDRVQEDState *s, QEDRequest *request, - unsigned int index, unsigned int n, bool flush, - BlockDriverCompletionFunc *cb, void *opaque); -int qed_write_l2_table_sync(BDRVQEDState *s, QEDRequest *request, - unsigned int index, unsigned int n, bool flush); - -/** - * Cluster functions - */ -void qed_find_cluster(BDRVQEDState *s, QEDRequest *request, uint64_t pos, - size_t len, QEDFindClusterFunc *cb, void *opaque); - -/** - * Consistency check - */ -int qed_check(BDRVQEDState *s, BdrvCheckResult *result, bool fix); - -QEDTable *qed_alloc_table(BDRVQEDState *s); - -/** - * Round down to the start of a cluster - */ -static inline uint64_t qed_start_of_cluster(BDRVQEDState *s, uint64_t offset) -{ - return offset & ~(uint64_t)(s->header.cluster_size - 1); -} - -static inline uint64_t qed_offset_into_cluster(BDRVQEDState *s, uint64_t offset) -{ - return offset & (s->header.cluster_size - 1); -} - -static inline uint64_t qed_bytes_to_clusters(BDRVQEDState *s, uint64_t bytes) -{ - return qed_start_of_cluster(s, bytes + (s->header.cluster_size - 1)) / - (s->header.cluster_size - 1); -} - -static inline unsigned int qed_l1_index(BDRVQEDState *s, uint64_t pos) -{ - return pos >> s->l1_shift; -} - -static inline unsigned int qed_l2_index(BDRVQEDState *s, uint64_t pos) -{ - return (pos >> s->l2_shift) & s->l2_mask; -} - -/** - * Test if a cluster offset is valid - */ -static inline bool qed_check_cluster_offset(BDRVQEDState *s, uint64_t offset) -{ - uint64_t header_size = (uint64_t)s->header.header_size * - s->header.cluster_size; - - if (offset & (s->header.cluster_size - 1)) { - return false; - } - return offset >= header_size && offset < s->file_size; -} - -/** - * Test if a table offset is valid - */ -static inline bool qed_check_table_offset(BDRVQEDState *s, uint64_t offset) -{ - uint64_t end_offset = offset + (s->header.table_size - 1) * - s->header.cluster_size; - - /* Overflow check */ - if (end_offset <= offset) { - return false; - } - - return qed_check_cluster_offset(s, offset) && - qed_check_cluster_offset(s, end_offset); -} - -static inline bool qed_offset_is_cluster_aligned(BDRVQEDState *s, - uint64_t offset) -{ - if (qed_offset_into_cluster(s, offset)) { - return false; - } - return true; -} - -static inline bool qed_offset_is_unalloc_cluster(uint64_t offset) -{ - if (offset == 0) { - return true; - } - return false; -} - -static inline bool qed_offset_is_zero_cluster(uint64_t offset) -{ - if (offset == 1) { - return true; - } - return false; -} - -#endif /* BLOCK_QED_H */ |