diff options
| -rw-r--r-- | qemu/block-qcow2.c | 53 |
1 files changed, 39 insertions, 14 deletions
diff --git a/qemu/block-qcow2.c b/qemu/block-qcow2.c index 171eb83f..9c8212bf 100644 --- a/qemu/block-qcow2.c +++ b/qemu/block-qcow2.c @@ -183,6 +183,13 @@ static void free_clusters(BlockDriverState *bs, int64_t offset, int64_t size); static int check_refcounts(BlockDriverState *bs); +static inline int64_t align_offset(int64_t offset, int n) +{ + offset = (offset + n - 1) & ~(n - 1); + return offset; +} + + static int qcow_probe(const uint8_t *buf, int buf_size, const char *filename) { const QCowHeader *cow_header = (const void *)buf; @@ -334,7 +341,8 @@ static int qcow_open(BlockDriverState *bs, const char *filename, int flags) if (s->l1_size < s->l1_vm_state_index) goto fail; s->l1_table_offset = header.l1_table_offset; - s->l1_table = qemu_malloc(s->l1_size * sizeof(uint64_t)); + s->l1_table = qemu_mallocz( + align_offset(s->l1_size * sizeof(uint64_t), 512)); if (!s->l1_table) goto fail; if (bdrv_pread(s->hd, s->l1_table_offset, s->l1_table, s->l1_size * sizeof(uint64_t)) != @@ -526,12 +534,6 @@ static inline int l2_cache_new_entry(BlockDriverState *bs) return min_index; } -static int64_t align_offset(int64_t offset, int n) -{ - offset = (offset + n - 1) & ~(n - 1); - return offset; -} - static int grow_l1_table(BlockDriverState *bs, int min_size) { BDRVQcowState *s = bs->opaque; @@ -551,7 +553,7 @@ static int grow_l1_table(BlockDriverState *bs, int min_size) #endif new_l1_size2 = sizeof(uint64_t) * new_l1_size; - new_l1_table = qemu_mallocz(new_l1_size2); + new_l1_table = qemu_mallocz(align_offset(new_l1_size2, 512)); if (!new_l1_table) return -ENOMEM; memcpy(new_l1_table, s->l1_table, s->l1_size * sizeof(uint64_t)); @@ -650,6 +652,31 @@ static uint64_t *l2_load(BlockDriverState *bs, uint64_t l2_offset) } /* + * Writes one sector of the L1 table to the disk (can't update single entries + * and we really don't want bdrv_pread to perform a read-modify-write) + */ +#define L1_ENTRIES_PER_SECTOR (512 / 8) +static int write_l1_entry(BDRVQcowState *s, int l1_index) +{ + uint64_t buf[L1_ENTRIES_PER_SECTOR]; + int l1_start_index; + int i; + + l1_start_index = l1_index & ~(L1_ENTRIES_PER_SECTOR - 1); + for (i = 0; i < L1_ENTRIES_PER_SECTOR; i++) { + buf[i] = cpu_to_be64(s->l1_table[l1_start_index + i]); + } + + if (bdrv_pwrite(s->hd, s->l1_table_offset + 8 * l1_start_index, + buf, sizeof(buf)) != sizeof(buf)) + { + return -1; + } + + return 0; +} + +/* * l2_allocate * * Allocate a new l2 entry in the file. If l1_index points to an already @@ -663,7 +690,7 @@ static uint64_t *l2_allocate(BlockDriverState *bs, int l1_index) { BDRVQcowState *s = bs->opaque; int min_index; - uint64_t old_l2_offset, tmp; + uint64_t old_l2_offset; uint64_t *l2_table, l2_offset; old_l2_offset = s->l1_table[l1_index]; @@ -675,11 +702,9 @@ static uint64_t *l2_allocate(BlockDriverState *bs, int l1_index) /* update the L1 entry */ s->l1_table[l1_index] = l2_offset | QCOW_OFLAG_COPIED; - - tmp = cpu_to_be64(l2_offset | QCOW_OFLAG_COPIED); - if (bdrv_pwrite(s->hd, s->l1_table_offset + l1_index * sizeof(tmp), - &tmp, sizeof(tmp)) != sizeof(tmp)) + if (write_l1_entry(s, l1_index) < 0) { return NULL; + } /* allocate a new entry in the l2 cache */ @@ -1829,7 +1854,7 @@ static int update_snapshot_refcount(BlockDriverState *bs, l1_size2 = l1_size * sizeof(uint64_t); l1_allocated = 0; if (l1_table_offset != s->l1_table_offset) { - l1_table = qemu_malloc(l1_size2); + l1_table = qemu_mallocz(align_offset(l1_size2, 512)); if (!l1_table) goto fail; l1_allocated = 1; |