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kvm tools, qcow: Use 'struct qcow_l2_table' instead of untyped array

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This patch converts disk/qcow.c to use 'struct qcow_l2_table' for tracking
dirty L2 tables later on in this series.

Cc: Asias He <asias.hejun@gmail.com>
Cc: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Prasad Joshi <prasadjoshi124@gmail.com>
Cc: Sasha Levin <levinsasha928@gmail.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
This commit is contained in:
Pekka Enberg
2015-06-01 16:39:46 +01:00
committed by Will Deacon
parent 473d58ff6e
commit fe8bdde0bd
1 changed files with 36 additions and 44 deletions
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disk/qcow.c
+36 -44
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@@ -121,21 +121,18 @@ error:
return -1;
}
static int search_table(struct qcow *q, u64 **table, u64 offset)
static struct qcow_l2_table *search_table(struct qcow *q, u64 offset)
{
struct qcow_l2_table *c;
struct qcow_l2_table *l2t;
*table = NULL;
c = search(&q->root, offset);
if (!c)
return -1;
l2t = search(&q->root, offset);
if (!l2t)
return NULL;
/* Update the LRU state, by moving the searched node to list tail */
list_move_tail(&c->list, &q->lru_list);
list_move_tail(&l2t->list, &q->lru_list);
*table = c->table;
return 0;
return l2t;
}
/* Allocates a new node for caching L2 table */
@@ -180,62 +177,57 @@ static inline u64 get_cluster_offset(struct qcow *q, u64 offset)
return offset & ((1 << header->cluster_bits)-1);
}
static int qcow_read_l2_table(struct qcow *q, u64 **table, u64 offset)
static struct qcow_l2_table *qcow_read_l2_table(struct qcow *q, u64 offset)
{
struct qcow_header *header = q->header;
struct qcow_l2_table *c;
struct qcow_l2_table *l2t;
u64 size;
u64 i;
u64 *t;
c = NULL;
*table = NULL;
size = 1 << header->l2_bits;
size = 1 << header->l2_bits;
/* search an entry for offset in cache */
if (search_table(q, table, offset) >= 0)
return 0;
l2t = search_table(q, offset);
if (l2t)
return l2t;
/* allocate new node for caching l2 table */
c = new_cache_table(q, offset);
if (!c)
l2t = new_cache_table(q, offset);
if (!l2t)
goto error;
t = c->table;
/* table not cached: read from the disk */
if (pread_in_full(q->fd, t, size * sizeof(u64), offset) < 0)
if (pread_in_full(q->fd, l2t->table, size * sizeof(u64), offset) < 0)
goto error;
/* cache the table */
if (cache_table(q, c) < 0)
if (cache_table(q, l2t) < 0)
goto error;
/* change cached table to CPU's byte-order */
for (i = 0; i < size; i++)
be64_to_cpus(&t[i]);
be64_to_cpus(&l2t->table[i]);
*table = t;
return 0;
return l2t;
error:
free(c);
return -1;
free(l2t);
return NULL;
}
static ssize_t qcow_read_cluster(struct qcow *q, u64 offset, void *dst, u32 dst_len)
{
struct qcow_header *header = q->header;
struct qcow_table *table = &q->table;
struct qcow_l2_table *l2_table;
u64 l2_table_offset;
u64 l2_table_size;
u64 cluster_size;
u64 clust_offset;
u64 clust_start;
size_t length;
u64 *l2_table;
u64 l1_idx;
u64 l2_idx;
cluster_size = 1 << header->cluster_bits;
l1_idx = get_l1_index(q, offset);
@@ -257,14 +249,15 @@ static ssize_t qcow_read_cluster(struct qcow *q, u64 offset, void *dst, u32 dst_
l2_table_size = 1 << header->l2_bits;
/* read and cache level 2 table */
if (qcow_read_l2_table(q, &l2_table, l2_table_offset) < 0)
l2_table = qcow_read_l2_table(q, l2_table_offset);
if (!l2_table)
goto out_error;
l2_idx = get_l2_index(q, offset);
if (l2_idx >= l2_table_size)
goto out_error;
clust_start = l2_table[l2_idx] & ~header->oflag_mask;
clust_start = l2_table->table[l2_idx] & ~header->oflag_mask;
if (!clust_start)
goto zero_cluster;
@@ -367,7 +360,7 @@ static ssize_t qcow_write_cluster(struct qcow *q, u64 offset, void *buf, u32 src
{
struct qcow_header *header = q->header;
struct qcow_table *table = &q->table;
struct qcow_l2_table *c;
struct qcow_l2_table *l2t;
bool update_meta;
u64 clust_start;
u64 clust_off;
@@ -376,12 +369,11 @@ static ssize_t qcow_write_cluster(struct qcow *q, u64 offset, void *buf, u32 src
u64 l2t_idx;
u64 l2t_off;
u64 l2t_sz;
u64 *l2t;
u64 f_sz;
u64 len;
u64 t;
c = NULL;
l2t = NULL;
l2t_sz = 1 << header->l2_bits;
clust_sz = 1 << header->cluster_bits;
@@ -404,13 +396,13 @@ static ssize_t qcow_write_cluster(struct qcow *q, u64 offset, void *buf, u32 src
l2t_off = table->l1_table[l1t_idx] & ~header->oflag_mask;
if (l2t_off) {
/* read and cache l2 table */
if (qcow_read_l2_table(q, &l2t, l2t_off) < 0)
l2t = qcow_read_l2_table(q, l2t_off);
if (!l2t)
goto error;
} else {
c = new_cache_table(q, l2t_off);
if (!c)
l2t = new_cache_table(q, l2t_off);
if (!l2t)
goto error;
l2t = c->table;
/* Capture the state of the consistent QCOW image */
f_sz = file_size(q->fd);
@@ -418,7 +410,7 @@ static ssize_t qcow_write_cluster(struct qcow *q, u64 offset, void *buf, u32 src
goto free_cache;
/* Write the l2 table of 0's at the end of the file */
l2t_off = qcow_write_l2_table(q, l2t);
l2t_off = qcow_write_l2_table(q, l2t->table);
if (!l2t_off)
goto free_cache;
@@ -433,7 +425,7 @@ static ssize_t qcow_write_cluster(struct qcow *q, u64 offset, void *buf, u32 src
goto free_cache;
}
if (cache_table(q, c) < 0) {
if (cache_table(q, l2t) < 0) {
if (ftruncate(q->fd, f_sz) < 0)
goto free_cache;
@@ -449,7 +441,7 @@ static ssize_t qcow_write_cluster(struct qcow *q, u64 offset, void *buf, u32 src
if (!f_sz)
goto error;
clust_start = l2t[l2t_idx] & ~header->oflag_mask;
clust_start = l2t->table[l2t_idx] & ~header->oflag_mask;
if (!clust_start) {
clust_start = ALIGN(f_sz, clust_sz);
update_meta = true;
@@ -471,13 +463,13 @@ static ssize_t qcow_write_cluster(struct qcow *q, u64 offset, void *buf, u32 src
}
/* Update the cached level2 entry */
l2t[l2t_idx] = clust_start;
l2t->table[l2t_idx] = clust_start;
}
return len;
free_cache:
free(c);
free(l2t);
error:
return -1;
}