[Qemu-devel] [STABLE][PATCH 10/14] qcow2: Use bdrv_(p)write_sync for metadata writes

[Kevin Wolf <kwolf@redhat.com>]

Use bdrv_(p)write_sync to ensure metadata integrity in case of a crash.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
(cherry picked from commit 8b3b720620a1137a1b794fc3ed64734236f94e06)

Conflicts:

	block/qcow2-cluster.c
	block/qcow2-refcount.c
	block/qcow2-snapshot.c
	block/qcow2.c

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 block/qcow2-cluster.c  |   45 ++++++++++++++++++++++++---------------------
 block/qcow2-refcount.c |   31 ++++++++++++++++---------------
 block/qcow2-snapshot.c |   23 +++++++++++------------
 3 files changed, 51 insertions(+), 48 deletions(-)

diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c
index 8c67e3c..0a555dc 100644
--- a/block/qcow2-cluster.c
+++ b/block/qcow2-cluster.c
@@ -62,8 +62,8 @@ int qcow2_grow_l1_table(BlockDriverState *bs, int min_size)
 
     for(i = 0; i < s->l1_size; i++)
         new_l1_table[i] = cpu_to_be64(new_l1_table[i]);
-    ret = bdrv_pwrite(s->hd, new_l1_table_offset, new_l1_table, new_l1_size2);
-    if (ret != new_l1_size2)
+    ret = bdrv_pwrite_sync(s->hd, new_l1_table_offset, new_l1_table, new_l1_size2);
+    if (ret < 0)
         goto fail;
     for(i = 0; i < s->l1_size; i++)
         new_l1_table[i] = be64_to_cpu(new_l1_table[i]);
@@ -71,8 +71,8 @@ int qcow2_grow_l1_table(BlockDriverState *bs, int min_size)
     /* set new table */
     cpu_to_be32w((uint32_t*)data, new_l1_size);
     cpu_to_be64w((uint64_t*)(data + 4), new_l1_table_offset);
-    ret = bdrv_pwrite(s->hd, offsetof(QCowHeader, l1_size), data,sizeof(data));
-    if (ret != sizeof(data)) {
+    ret = bdrv_pwrite_sync(s->hd, offsetof(QCowHeader, l1_size), data,sizeof(data));
+    if (ret < 0) {
         goto fail;
     }
     qemu_free(s->l1_table);
@@ -84,7 +84,7 @@ int qcow2_grow_l1_table(BlockDriverState *bs, int min_size)
  fail:
     qemu_free(new_l1_table);
     qcow2_free_clusters(bs, new_l1_table_offset, new_l1_size2);
-    return ret < 0 ? ret : -EIO;
+    return ret;
 }
 
 void qcow2_l2_cache_reset(BlockDriverState *bs)
@@ -188,17 +188,17 @@ static int write_l1_entry(BDRVQcowState *s, int l1_index)
 {
     uint64_t buf[L1_ENTRIES_PER_SECTOR];
     int l1_start_index;
-    int i;
+    int i, ret;
 
     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;
+    ret = bdrv_pwrite_sync(s->hd, s->l1_table_offset + 8 * l1_start_index,
+        buf, sizeof(buf));
+    if (ret < 0) {
+        return ret;
     }
 
     return 0;
@@ -221,6 +221,7 @@ static uint64_t *l2_allocate(BlockDriverState *bs, int l1_index)
     uint64_t old_l2_offset;
     uint64_t *l2_table;
     int64_t l2_offset;
+    int ret;
 
     old_l2_offset = s->l1_table[l1_index];
 
@@ -247,10 +248,11 @@ static uint64_t *l2_allocate(BlockDriverState *bs, int l1_index)
             goto fail;
     }
     /* write the l2 table to the file */
-    if (bdrv_pwrite(s->hd, l2_offset,
-                    l2_table, s->l2_size * sizeof(uint64_t)) !=
-        s->l2_size * sizeof(uint64_t))
+    ret = bdrv_pwrite_sync(s->hd, l2_offset, l2_table,
+        s->l2_size * sizeof(uint64_t));
+    if (ret < 0) {
         goto fail;
+    }
 
     /* update the L1 entry */
     s->l1_table[l1_index] = l2_offset | QCOW_OFLAG_COPIED;
@@ -384,8 +386,8 @@ static int copy_sectors(BlockDriverState *bs, uint64_t start_sect,
                         s->cluster_data, n, 1,
                         &s->aes_encrypt_key);
     }
-    ret = bdrv_write(s->hd, (cluster_offset >> 9) + n_start,
-                     s->cluster_data, n);
+    ret = bdrv_write_sync(s->hd, (cluster_offset >> 9) + n_start,
+        s->cluster_data, n);
     if (ret < 0)
         return ret;
     return 0;
@@ -597,10 +599,10 @@ uint64_t qcow2_alloc_compressed_cluster_offset(BlockDriverState *bs,
     /* compressed clusters never have the copied flag */
 
     l2_table[l2_index] = cpu_to_be64(cluster_offset);
-    if (bdrv_pwrite(s->hd,
+    if (bdrv_pwrite_sync(s->hd,
                     l2_offset + l2_index * sizeof(uint64_t),
                     l2_table + l2_index,
-                    sizeof(uint64_t)) != sizeof(uint64_t))
+                    sizeof(uint64_t)) < 0)
         return 0;
 
     return cluster_offset;
@@ -618,11 +620,12 @@ static int write_l2_entries(BDRVQcowState *s, uint64_t *l2_table,
     int start_offset = (8 * l2_index) & ~511;
     int end_offset = (8 * (l2_index + num) + 511) & ~511;
     size_t len = end_offset - start_offset;
+    int ret;
 
-    if (bdrv_pwrite(s->hd, l2_offset + start_offset, &l2_table[l2_start_index],
-        len) != len)
-    {
-        return -1;
+    ret = bdrv_pwrite_sync(s->hd, l2_offset + start_offset,
+        &l2_table[l2_start_index], len);
+    if (ret < 0) {
+        return ret;
     }
 
     return 0;
diff --git a/block/qcow2-refcount.c b/block/qcow2-refcount.c
index ff2cf6d..06998da 100644
--- a/block/qcow2-refcount.c
+++ b/block/qcow2-refcount.c
@@ -42,8 +42,8 @@ static int write_refcount_block(BDRVQcowState *s)
         return 0;
     }
 
-    if (bdrv_pwrite(s->hd, s->refcount_block_cache_offset,
-            s->refcount_block_cache, size) != size)
+    if (bdrv_pwrite_sync(s->hd, s->refcount_block_cache_offset,
+            s->refcount_block_cache, size) < 0)
     {
         return -EIO;
     }
@@ -246,7 +246,7 @@ static int64_t alloc_refcount_block(BlockDriverState *bs, int64_t cluster_index)
     }
 
     /* Now the new refcount block needs to be written to disk */
-    ret = bdrv_pwrite(s->hd, new_block, s->refcount_block_cache,
+    ret = bdrv_pwrite_sync(s->hd, new_block, s->refcount_block_cache,
         s->cluster_size);
     if (ret < 0) {
         goto fail_block;
@@ -255,7 +255,7 @@ static int64_t alloc_refcount_block(BlockDriverState *bs, int64_t cluster_index)
     /* If the refcount table is big enough, just hook the block up there */
     if (refcount_table_index < s->refcount_table_size) {
         uint64_t data64 = cpu_to_be64(new_block);
-        ret = bdrv_pwrite(s->hd,
+        ret = bdrv_pwrite_sync(s->hd,
             s->refcount_table_offset + refcount_table_index * sizeof(uint64_t),
             &data64, sizeof(data64));
         if (ret < 0) {
@@ -332,7 +332,7 @@ static int64_t alloc_refcount_block(BlockDriverState *bs, int64_t cluster_index)
     }
 
     /* Write refcount blocks to disk */
-    ret = bdrv_pwrite(s->hd, meta_offset, new_blocks,
+    ret = bdrv_pwrite_sync(s->hd, meta_offset, new_blocks,
         blocks_clusters * s->cluster_size);
     qemu_free(new_blocks);
     if (ret < 0) {
@@ -344,7 +344,7 @@ static int64_t alloc_refcount_block(BlockDriverState *bs, int64_t cluster_index)
         cpu_to_be64s(&new_table[i]);
     }
 
-    ret = bdrv_pwrite(s->hd, table_offset, new_table,
+    ret = bdrv_pwrite_sync(s->hd, table_offset, new_table,
         table_size * sizeof(uint64_t));
     if (ret < 0) {
         goto fail_table;
@@ -358,7 +358,7 @@ static int64_t alloc_refcount_block(BlockDriverState *bs, int64_t cluster_index)
     uint8_t data[12];
     cpu_to_be64w((uint64_t*)data, table_offset);
     cpu_to_be32w((uint32_t*)(data + 8), table_clusters);
-    ret = bdrv_pwrite(s->hd, offsetof(QCowHeader, refcount_table_offset),
+    ret = bdrv_pwrite_sync(s->hd, offsetof(QCowHeader, refcount_table_offset),
         data, sizeof(data));
     if (ret < 0) {
         goto fail_table;
@@ -397,6 +397,7 @@ static int write_refcount_block_entries(BDRVQcowState *s,
     int64_t refcount_block_offset, int first_index, int last_index)
 {
     size_t size;
+    int ret;
 
     if (cache_refcount_updates) {
         return 0;
@@ -411,11 +412,11 @@ static int write_refcount_block_entries(BDRVQcowState *s,
         & ~(REFCOUNTS_PER_SECTOR - 1);
 
     size = (last_index - first_index) << REFCOUNT_SHIFT;
-    if (bdrv_pwrite(s->hd,
+    ret = bdrv_pwrite_sync(s->hd,
         refcount_block_offset + (first_index << REFCOUNT_SHIFT),
-        &s->refcount_block_cache[first_index], size) != size)
-    {
-        return -EIO;
+        &s->refcount_block_cache[first_index], size);
+    if (ret < 0) {
+        return ret;
     }
 
     return 0;
@@ -771,8 +772,8 @@ int qcow2_update_snapshot_refcount(BlockDriverState *bs,
                 }
             }
             if (l2_modified) {
-                if (bdrv_pwrite(s->hd,
-                                l2_offset, l2_table, l2_size) != l2_size)
+                if (bdrv_pwrite_sync(s->hd,
+                                l2_offset, l2_table, l2_size) < 0)
                     goto fail;
             }
 
@@ -793,8 +794,8 @@ int qcow2_update_snapshot_refcount(BlockDriverState *bs,
     if (l1_modified) {
         for(i = 0; i < l1_size; i++)
             cpu_to_be64s(&l1_table[i]);
-        if (bdrv_pwrite(s->hd, l1_table_offset, l1_table,
-                        l1_size2) != l1_size2)
+        if (bdrv_pwrite_sync(s->hd, l1_table_offset, l1_table,
+                        l1_size2) < 0)
             goto fail;
         for(i = 0; i < l1_size; i++)
             be64_to_cpus(&l1_table[i]);
diff --git a/block/qcow2-snapshot.c b/block/qcow2-snapshot.c
index 8ddaea2..64af361 100644
--- a/block/qcow2-snapshot.c
+++ b/block/qcow2-snapshot.c
@@ -158,25 +158,25 @@ static int qcow_write_snapshots(BlockDriverState *bs)
         h.id_str_size = cpu_to_be16(id_str_size);
         h.name_size = cpu_to_be16(name_size);
         offset = align_offset(offset, 8);
-        if (bdrv_pwrite(s->hd, offset, &h, sizeof(h)) != sizeof(h))
+        if (bdrv_pwrite_sync(s->hd, offset, &h, sizeof(h)) < 0)
             goto fail;
         offset += sizeof(h);
-        if (bdrv_pwrite(s->hd, offset, sn->id_str, id_str_size) != id_str_size)
+        if (bdrv_pwrite_sync(s->hd, offset, sn->id_str, id_str_size) < 0)
             goto fail;
         offset += id_str_size;
-        if (bdrv_pwrite(s->hd, offset, sn->name, name_size) != name_size)
+        if (bdrv_pwrite_sync(s->hd, offset, sn->name, name_size) < 0)
             goto fail;
         offset += name_size;
     }
 
     /* update the various header fields */
     data64 = cpu_to_be64(snapshots_offset);
-    if (bdrv_pwrite(s->hd, offsetof(QCowHeader, snapshots_offset),
-                    &data64, sizeof(data64)) != sizeof(data64))
+    if (bdrv_pwrite_sync(s->hd, offsetof(QCowHeader, snapshots_offset),
+                    &data64, sizeof(data64)) < 0)
         goto fail;
     data32 = cpu_to_be32(s->nb_snapshots);
-    if (bdrv_pwrite(s->hd, offsetof(QCowHeader, nb_snapshots),
-                    &data32, sizeof(data32)) != sizeof(data32))
+    if (bdrv_pwrite_sync(s->hd, offsetof(QCowHeader, nb_snapshots),
+                    &data32, sizeof(data32)) < 0)
         goto fail;
 
     /* free the old snapshot table */
@@ -284,9 +284,8 @@ int qcow2_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info)
     for(i = 0; i < s->l1_size; i++) {
         l1_table[i] = cpu_to_be64(s->l1_table[i]);
     }
-    if (bdrv_pwrite(s->hd, sn->l1_table_offset,
-                    l1_table, s->l1_size * sizeof(uint64_t)) !=
-        (s->l1_size * sizeof(uint64_t)))
+    if (bdrv_pwrite_sync(s->hd, sn->l1_table_offset,
+                    l1_table, s->l1_size * sizeof(uint64_t)) < 0)
         goto fail;
     qemu_free(l1_table);
     l1_table = NULL;
@@ -335,8 +334,8 @@ int qcow2_snapshot_goto(BlockDriverState *bs, const char *snapshot_id)
     if (bdrv_pread(s->hd, sn->l1_table_offset,
                    s->l1_table, l1_size2) != l1_size2)
         goto fail;
-    if (bdrv_pwrite(s->hd, s->l1_table_offset,
-                    s->l1_table, l1_size2) != l1_size2)
+    if (bdrv_pwrite_sync(s->hd, s->l1_table_offset,
+                    s->l1_table, l1_size2) < 0)
         goto fail;
     for(i = 0;i < s->l1_size; i++) {
         be64_to_cpus(&s->l1_table[i]);
-- 
1.7.1.1