diff options
author | Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> | 2010-12-06 16:08:01 +0000 |
---|---|---|
committer | Kevin Wolf <kwolf@redhat.com> | 2010-12-17 16:11:04 +0100 |
commit | 298800cae72eb2a549374189e87615b2b0b79262 (patch) | |
tree | fadedcd0842fa60989078a4aa8c1959a27adbbd0 /block/qed.h | |
parent | 75411d236d93d79d8052e0116c3eeebe23e2778b (diff) | |
download | hqemu-298800cae72eb2a549374189e87615b2b0b79262.zip hqemu-298800cae72eb2a549374189e87615b2b0b79262.tar.gz |
qed: Table, L2 cache, and cluster functions
This patch adds code to look up data cluster offsets in the image via
the L1/L2 tables. The L2 tables are writethrough cached in memory for
performance (each read/write requires a lookup so it is essential to
cache the tables).
With cluster lookup code in place it is possible to implement
bdrv_is_allocated() to query the number of contiguous
allocated/unallocated clusters.
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Diffstat (limited to 'block/qed.h')
-rw-r--r-- | block/qed.h | 123 |
1 files changed, 123 insertions, 0 deletions
diff --git a/block/qed.h b/block/qed.h index 1f8a125..6d49a4d 100644 --- a/block/qed.h +++ b/block/qed.h @@ -96,16 +96,118 @@ typedef struct { } 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; + +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; } BDRVQEDState; +enum { + QED_CLUSTER_FOUND, /* 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); + +/** + * 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 */ @@ -114,6 +216,27 @@ 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 unsigned int qed_bytes_to_clusters(BDRVQEDState *s, size_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 */ |