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qed: protect table cache with CoMutex

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This makes the driver thread-safe.  The CoMutex is dropped temporarily
while accessing the data clusters or the backing file.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20170629132749.997-10-pbonzini@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Fam Zheng <famz@redhat.com>
This commit is contained in:
Paolo Bonzini 2017-06-29 15:27:47 +02:00 • committed by Fam Zheng
parent 61c7887e0f
commit 1f01e50b83
5 changed files with 129 additions and 54 deletions
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24
block/qed-table.c
View file

@ -18,6 +18,7 @@
#include "qed.h"
#include "qemu/bswap.h"
/* Called either from qed_check or with table_lock held. */
static int qed_read_table(BDRVQEDState *s, uint64_t offset, QEDTable *table)
{
QEMUIOVector qiov;
@ -32,18 +33,22 @@ static int qed_read_table(BDRVQEDState *s, uint64_t offset, QEDTable *table)
trace_qed_read_table(s, offset, table);
if (qemu_in_coroutine()) {
qemu_co_mutex_unlock(&s->table_lock);
}
ret = bdrv_preadv(s->bs->file, offset, &qiov);
if (qemu_in_coroutine()) {
qemu_co_mutex_lock(&s->table_lock);
}
if (ret < 0) {
goto out;
}
/* Byteswap offsets */
qed_acquire(s);
noffsets = qiov.size / sizeof(uint64_t);
for (i = 0; i < noffsets; i++) {
table->offsets[i] = le64_to_cpu(table->offsets[i]);
}
qed_release(s);
ret = 0;
out:
@ -61,6 +66,8 @@ out:
* @index: Index of first element
* @n: Number of elements
* @flush: Whether or not to sync to disk
*
* Called either from qed_check or with table_lock held.
*/
static int qed_write_table(BDRVQEDState *s, uint64_t offset, QEDTable *table,
unsigned int index, unsigned int n, bool flush)
@ -97,16 +104,20 @@ static int qed_write_table(BDRVQEDState *s, uint64_t offset, QEDTable *table,
/* Adjust for offset into table */
offset += start * sizeof(uint64_t);
if (qemu_in_coroutine()) {
qemu_co_mutex_unlock(&s->table_lock);
}
ret = bdrv_pwritev(s->bs->file, offset, &qiov);
if (qemu_in_coroutine()) {
qemu_co_mutex_lock(&s->table_lock);
}
trace_qed_write_table_cb(s, table, flush, ret);
if (ret < 0) {
goto out;
}
if (flush) {
qed_acquire(s);
ret = bdrv_flush(s->bs);
qed_release(s);
if (ret < 0) {
goto out;
}
@ -123,6 +134,7 @@ int qed_read_l1_table_sync(BDRVQEDState *s)
return qed_read_table(s, s->header.l1_table_offset, s->l1_table);
}
/* Called either from qed_check or with table_lock held. */
int qed_write_l1_table(BDRVQEDState *s, unsigned int index, unsigned int n)
{
BLKDBG_EVENT(s->bs->file, BLKDBG_L1_UPDATE);
@ -136,6 +148,7 @@ int qed_write_l1_table_sync(BDRVQEDState *s, unsigned int index,
return qed_write_l1_table(s, index, n);
}
/* Called either from qed_check or with table_lock held. */
int qed_read_l2_table(BDRVQEDState *s, QEDRequest *request, uint64_t offset)
{
int ret;
@ -154,7 +167,6 @@ int qed_read_l2_table(BDRVQEDState *s, QEDRequest *request, uint64_t offset)
BLKDBG_EVENT(s->bs->file, BLKDBG_L2_LOAD);
ret = qed_read_table(s, offset, request->l2_table->table);
qed_acquire(s);
if (ret) {
/* can't trust loaded L2 table anymore */
qed_unref_l2_cache_entry(request->l2_table);
@ -170,7 +182,6 @@ int qed_read_l2_table(BDRVQEDState *s, QEDRequest *request, uint64_t offset)
request->l2_table = qed_find_l2_cache_entry(&s->l2_cache, offset);
assert(request->l2_table != NULL);
}
qed_release(s);
return ret;
}
@ -180,6 +191,7 @@ int qed_read_l2_table_sync(BDRVQEDState *s, QEDRequest *request, uint64_t offset
return qed_read_l2_table(s, request, offset);
}
/* Called either from qed_check or with table_lock held. */
int qed_write_l2_table(BDRVQEDState *s, QEDRequest *request,
unsigned int index, unsigned int n, bool flush)
{