block: Open the underlying image file in generic code

Format drivers shouldn't need to bother with things like file names, but rather
just get an open BlockDriverState for the underlying protocol. This patch
introduces this behaviour for bdrv_open implementation. For protocols which
need to access the filename to open their file/device/connection/... a new
callback bdrv_file_open is introduced which doesn't get an underlying file
opened.

For now, also some of the more obscure formats use bdrv_file_open because they
open() the file themselves instead of using the block.c functions. They need to
be fixed in later patches.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>

1 files changed, 30 insertions, 37 deletions

diff --git a/block/qcow.c b/block/qcow.c
index c619984a0..2883c40f8 100644
--- a/block/qcow.c
+++ b/block/qcow.c
@@ -76,7 +76,7 @@ typedef struct BDRVQcowState {
     AES_KEY aes_decrypt_key;
 } BDRVQcowState;
 
-static int decompress_cluster(BDRVQcowState *s, uint64_t cluster_offset);
+static int decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset);
 
 static int qcow_probe(const uint8_t *buf, int buf_size, const char *filename)
 {
@@ -90,16 +90,13 @@ static int qcow_probe(const uint8_t *buf, int buf_size, const char *filename)
         return 0;
 }
 
-static int qcow_open(BlockDriverState *bs, const char *filename, int flags)
+static int qcow_open(BlockDriverState *bs, int flags)
 {
     BDRVQcowState *s = bs->opaque;
-    int len, i, shift, ret;
+    int len, i, shift;
     QCowHeader header;
 
-    ret = bdrv_file_open(&s->hd, filename, flags);
-    if (ret < 0)
-        return ret;
-    if (bdrv_pread(s->hd, 0, &header, sizeof(header)) != sizeof(header))
+    if (bdrv_pread(bs->file, 0, &header, sizeof(header)) != sizeof(header))
         goto fail;
     be32_to_cpus(&header.magic);
     be32_to_cpus(&header.version);
@@ -135,7 +132,7 @@ static int qcow_open(BlockDriverState *bs, const char *filename, int flags)
     s->l1_table = qemu_malloc(s->l1_size * sizeof(uint64_t));
     if (!s->l1_table)
         goto fail;
-    if (bdrv_pread(s->hd, s->l1_table_offset, s->l1_table, s->l1_size * sizeof(uint64_t)) !=
+    if (bdrv_pread(bs->file, s->l1_table_offset, s->l1_table, s->l1_size * sizeof(uint64_t)) !=
         s->l1_size * sizeof(uint64_t))
         goto fail;
     for(i = 0;i < s->l1_size; i++) {
@@ -158,7 +155,7 @@ static int qcow_open(BlockDriverState *bs, const char *filename, int flags)
         len = header.backing_file_size;
         if (len > 1023)
             len = 1023;
-        if (bdrv_pread(s->hd, header.backing_file_offset, bs->backing_file, len) != len)
+        if (bdrv_pread(bs->file, header.backing_file_offset, bs->backing_file, len) != len)
             goto fail;
         bs->backing_file[len] = '\0';
     }
@@ -169,7 +166,6 @@ static int qcow_open(BlockDriverState *bs, const char *filename, int flags)
     qemu_free(s->l2_cache);
     qemu_free(s->cluster_cache);
     qemu_free(s->cluster_data);
-    bdrv_delete(s->hd);
     return -1;
 }
 
@@ -271,13 +267,13 @@ static uint64_t get_cluster_offset(BlockDriverState *bs,
         if (!allocate)
             return 0;
         /* allocate a new l2 entry */
-        l2_offset = bdrv_getlength(s->hd);
+        l2_offset = bdrv_getlength(bs->file);
         /* round to cluster size */
         l2_offset = (l2_offset + s->cluster_size - 1) & ~(s->cluster_size - 1);
         /* update the L1 entry */
         s->l1_table[l1_index] = l2_offset;
         tmp = cpu_to_be64(l2_offset);
-        if (bdrv_pwrite(s->hd, s->l1_table_offset + l1_index * sizeof(tmp),
+        if (bdrv_pwrite(bs->file, s->l1_table_offset + l1_index * sizeof(tmp),
                         &tmp, sizeof(tmp)) != sizeof(tmp))
             return 0;
         new_l2_table = 1;
@@ -306,11 +302,11 @@ static uint64_t get_cluster_offset(BlockDriverState *bs,
     l2_table = s->l2_cache + (min_index << s->l2_bits);
     if (new_l2_table) {
         memset(l2_table, 0, s->l2_size * sizeof(uint64_t));
-        if (bdrv_pwrite(s->hd, l2_offset, l2_table, s->l2_size * sizeof(uint64_t)) !=
+        if (bdrv_pwrite(bs->file, l2_offset, l2_table, s->l2_size * sizeof(uint64_t)) !=
             s->l2_size * sizeof(uint64_t))
             return 0;
     } else {
-        if (bdrv_pread(s->hd, l2_offset, l2_table, s->l2_size * sizeof(uint64_t)) !=
+        if (bdrv_pread(bs->file, l2_offset, l2_table, s->l2_size * sizeof(uint64_t)) !=
             s->l2_size * sizeof(uint64_t))
             return 0;
     }
@@ -329,22 +325,22 @@ static uint64_t get_cluster_offset(BlockDriverState *bs,
             /* if the cluster is already compressed, we must
                decompress it in the case it is not completely
                overwritten */
-            if (decompress_cluster(s, cluster_offset) < 0)
+            if (decompress_cluster(bs, cluster_offset) < 0)
                 return 0;
-            cluster_offset = bdrv_getlength(s->hd);
+            cluster_offset = bdrv_getlength(bs->file);
             cluster_offset = (cluster_offset + s->cluster_size - 1) &
                 ~(s->cluster_size - 1);
             /* write the cluster content */
-            if (bdrv_pwrite(s->hd, cluster_offset, s->cluster_cache, s->cluster_size) !=
+            if (bdrv_pwrite(bs->file, cluster_offset, s->cluster_cache, s->cluster_size) !=
                 s->cluster_size)
                 return -1;
         } else {
-            cluster_offset = bdrv_getlength(s->hd);
+            cluster_offset = bdrv_getlength(bs->file);
             if (allocate == 1) {
                 /* round to cluster size */
                 cluster_offset = (cluster_offset + s->cluster_size - 1) &
                     ~(s->cluster_size - 1);
-                bdrv_truncate(s->hd, cluster_offset + s->cluster_size);
+                bdrv_truncate(bs->file, cluster_offset + s->cluster_size);
                 /* if encrypted, we must initialize the cluster
                    content which won't be written */
                 if (s->crypt_method &&
@@ -358,7 +354,7 @@ static uint64_t get_cluster_offset(BlockDriverState *bs,
                                             s->cluster_data,
                                             s->cluster_data + 512, 1, 1,
                                             &s->aes_encrypt_key);
-                            if (bdrv_pwrite(s->hd, cluster_offset + i * 512,
+                            if (bdrv_pwrite(bs->file, cluster_offset + i * 512,
                                             s->cluster_data, 512) != 512)
                                 return -1;
                         }
@@ -372,7 +368,7 @@ static uint64_t get_cluster_offset(BlockDriverState *bs,
         /* update L2 table */
         tmp = cpu_to_be64(cluster_offset);
         l2_table[l2_index] = tmp;
-        if (bdrv_pwrite(s->hd,
+        if (bdrv_pwrite(bs->file,
                         l2_offset + l2_index * sizeof(tmp), &tmp, sizeof(tmp)) != sizeof(tmp))
             return 0;
     }
@@ -422,8 +418,9 @@ static int decompress_buffer(uint8_t *out_buf, int out_buf_size,
     return 0;
 }
 
-static int decompress_cluster(BDRVQcowState *s, uint64_t cluster_offset)
+static int decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset)
 {
+    BDRVQcowState *s = bs->opaque;
     int ret, csize;
     uint64_t coffset;
 
@@ -431,7 +428,7 @@ static int decompress_cluster(BDRVQcowState *s, uint64_t cluster_offset)
     if (s->cluster_cache_offset != coffset) {
         csize = cluster_offset >> (63 - s->cluster_bits);
         csize &= (s->cluster_size - 1);
-        ret = bdrv_pread(s->hd, coffset, s->cluster_data, csize);
+        ret = bdrv_pread(bs->file, coffset, s->cluster_data, csize);
         if (ret != csize)
             return -1;
         if (decompress_buffer(s->cluster_cache, s->cluster_size,
@@ -468,11 +465,11 @@ static int qcow_read(BlockDriverState *bs, int64_t sector_num,
                 memset(buf, 0, 512 * n);
             }
         } else if (cluster_offset & QCOW_OFLAG_COMPRESSED) {
-            if (decompress_cluster(s, cluster_offset) < 0)
+            if (decompress_cluster(bs, cluster_offset) < 0)
                 return -1;
             memcpy(buf, s->cluster_cache + index_in_cluster * 512, 512 * n);
         } else {
-            ret = bdrv_pread(s->hd, cluster_offset + index_in_cluster * 512, buf, n * 512);
+            ret = bdrv_pread(bs->file, cluster_offset + index_in_cluster * 512, buf, n * 512);
             if (ret != n * 512)
                 return -1;
             if (s->crypt_method) {
@@ -601,7 +598,7 @@ static void qcow_aio_read_cb(void *opaque, int ret)
         }
     } else if (acb->cluster_offset & QCOW_OFLAG_COMPRESSED) {
         /* add AIO support for compressed blocks ? */
-        if (decompress_cluster(s, acb->cluster_offset) < 0)
+        if (decompress_cluster(bs, acb->cluster_offset) < 0)
             goto done;
         memcpy(acb->buf,
                s->cluster_cache + index_in_cluster * 512, 512 * acb->n);
@@ -614,7 +611,7 @@ static void qcow_aio_read_cb(void *opaque, int ret)
         acb->hd_iov.iov_base = (void *)acb->buf;
         acb->hd_iov.iov_len = acb->n * 512;
         qemu_iovec_init_external(&acb->hd_qiov, &acb->hd_iov, 1);
-        acb->hd_aiocb = bdrv_aio_readv(s->hd,
+        acb->hd_aiocb = bdrv_aio_readv(bs->file,
                             (acb->cluster_offset >> 9) + index_in_cluster,
                             &acb->hd_qiov, acb->n, qcow_aio_read_cb, acb);
         if (acb->hd_aiocb == NULL)
@@ -699,7 +696,7 @@ static void qcow_aio_write_cb(void *opaque, int ret)
     acb->hd_iov.iov_base = (void *)src_buf;
     acb->hd_iov.iov_len = acb->n * 512;
     qemu_iovec_init_external(&acb->hd_qiov, &acb->hd_iov, 1);
-    acb->hd_aiocb = bdrv_aio_writev(s->hd,
+    acb->hd_aiocb = bdrv_aio_writev(bs->file,
                                     (cluster_offset >> 9) + index_in_cluster,
                                     &acb->hd_qiov, acb->n,
                                     qcow_aio_write_cb, acb);
@@ -739,7 +736,6 @@ static void qcow_close(BlockDriverState *bs)
     qemu_free(s->l2_cache);
     qemu_free(s->cluster_cache);
     qemu_free(s->cluster_data);
-    bdrv_delete(s->hd);
 }
 
 static int qcow_create(const char *filename, QEMUOptionParameter *options)
@@ -839,9 +835,9 @@ static int qcow_make_empty(BlockDriverState *bs)
     int ret;
 
     memset(s->l1_table, 0, l1_length);
-    if (bdrv_pwrite(s->hd, s->l1_table_offset, s->l1_table, l1_length) < 0)
+    if (bdrv_pwrite(bs->file, s->l1_table_offset, s->l1_table, l1_length) < 0)
 	return -1;
-    ret = bdrv_truncate(s->hd, s->l1_table_offset + l1_length);
+    ret = bdrv_truncate(bs->file, s->l1_table_offset + l1_length);
     if (ret < 0)
         return ret;
 
@@ -902,7 +898,7 @@ static int qcow_write_compressed(BlockDriverState *bs, int64_t sector_num,
         cluster_offset = get_cluster_offset(bs, sector_num << 9, 2,
                                             out_len, 0, 0);
         cluster_offset &= s->cluster_offset_mask;
-        if (bdrv_pwrite(s->hd, cluster_offset, out_buf, out_len) != out_len) {
+        if (bdrv_pwrite(bs->file, cluster_offset, out_buf, out_len) != out_len) {
             qemu_free(out_buf);
             return -1;
         }
@@ -914,16 +910,13 @@ static int qcow_write_compressed(BlockDriverState *bs, int64_t sector_num,
 
 static void qcow_flush(BlockDriverState *bs)
 {
-    BDRVQcowState *s = bs->opaque;
-    bdrv_flush(s->hd);
+    bdrv_flush(bs->file);
 }
 
 static BlockDriverAIOCB *qcow_aio_flush(BlockDriverState *bs,
         BlockDriverCompletionFunc *cb, void *opaque)
 {
-    BDRVQcowState *s = bs->opaque;
-
-    return bdrv_aio_flush(s->hd, cb, opaque);
+    return bdrv_aio_flush(bs->file, cb, opaque);
 }
 
 static int qcow_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)