block/parallels: provide _co_readv routine for parallels format driver

[mirror_qemu.git] / block / parallels.c

diff --git a/block/parallels.c b/block/parallels.c
index 2a814f3db4253695cf85b2a6f63fabc202ae808a..f3ffecec34ae14bf81de8eca07cb2861e7084434 100644 (file)
--- a/block/parallels.c
+++ b/block/parallels.c
@@ -35,7 +35,7 @@
 #define HEADER_SIZE 64
 
 // always little-endian
-struct parallels_header {
+typedef struct ParallelsHeader {
     char magic[16]; // "WithoutFreeSpace"
     uint32_t version;
     uint32_t heads;
@@ -46,9 +46,13 @@ struct parallels_header {
     uint32_t inuse;
     uint32_t data_off;
     char padding[12];
-} QEMU_PACKED;
+} QEMU_PACKED ParallelsHeader;
 
 typedef struct BDRVParallelsState {
+    /** Locking is conservative, the lock protects
+     *   - image file extending (truncate, fallocate)
+     *   - any access to block allocation table
+     */
     CoMutex lock;
 
     uint32_t *catalog_bitmap;
@@ -61,7 +65,7 @@ typedef struct BDRVParallelsState {
 
 static int parallels_probe(const uint8_t *buf, int buf_size, const char *filename)
 {
-    const struct parallels_header *ph = (const void *)buf;
+    const ParallelsHeader *ph = (const void *)buf;
 
     if (buf_size < HEADER_SIZE)
         return 0;
@@ -79,7 +83,7 @@ static int parallels_open(BlockDriverState *bs, QDict *options, int flags,
 {
     BDRVParallelsState *s = bs->opaque;
     int i;
-    struct parallels_header ph;
+    ParallelsHeader ph;
     int ret;
 
     bs->read_only = 1; // no write support yet
@@ -146,47 +150,85 @@ fail:
     return ret;
 }
 
-static int64_t seek_to_sector(BlockDriverState *bs, int64_t sector_num)
+static int64_t seek_to_sector(BDRVParallelsState *s, int64_t sector_num)
 {
-    BDRVParallelsState *s = bs->opaque;
     uint32_t index, offset;
 
     index = sector_num / s->tracks;
     offset = sector_num % s->tracks;
 
     /* not allocated */
-    if ((index > s->catalog_size) || (s->catalog_bitmap[index] == 0))
+    if ((index >= s->catalog_size) || (s->catalog_bitmap[index] == 0))
         return -1;
-    return
-        ((uint64_t)s->catalog_bitmap[index] * s->off_multiplier + offset) * 512;
+    return (uint64_t)s->catalog_bitmap[index] * s->off_multiplier + offset;
 }
 
-static int parallels_read(BlockDriverState *bs, int64_t sector_num,
-                    uint8_t *buf, int nb_sectors)
+static int cluster_remainder(BDRVParallelsState *s, int64_t sector_num,
+        int nb_sectors)
 {
-    while (nb_sectors > 0) {
-        int64_t position = seek_to_sector(bs, sector_num);
-        if (position >= 0) {
-            if (bdrv_pread(bs->file, position, buf, 512) != 512)
-                return -1;
-        } else {
-            memset(buf, 0, 512);
-        }
-        nb_sectors--;
-        sector_num++;
-        buf += 512;
-    }
-    return 0;
+    int ret = s->tracks - sector_num % s->tracks;
+    return MIN(nb_sectors, ret);
 }
 
-static coroutine_fn int parallels_co_read(BlockDriverState *bs, int64_t sector_num,
-                                          uint8_t *buf, int nb_sectors)
+static int64_t coroutine_fn parallels_co_get_block_status(BlockDriverState *bs,
+        int64_t sector_num, int nb_sectors, int *pnum)
 {
-    int ret;
     BDRVParallelsState *s = bs->opaque;
+    int64_t offset;
+
     qemu_co_mutex_lock(&s->lock);
-    ret = parallels_read(bs, sector_num, buf, nb_sectors);
+    offset = seek_to_sector(s, sector_num);
     qemu_co_mutex_unlock(&s->lock);
+
+    *pnum = cluster_remainder(s, sector_num, nb_sectors);
+
+    if (offset < 0) {
+        return 0;
+    }
+
+    return (offset << BDRV_SECTOR_BITS) |
+        BDRV_BLOCK_DATA | BDRV_BLOCK_OFFSET_VALID;
+}
+
+static coroutine_fn int parallels_co_readv(BlockDriverState *bs,
+        int64_t sector_num, int nb_sectors, QEMUIOVector *qiov)
+{
+    BDRVParallelsState *s = bs->opaque;
+    uint64_t bytes_done = 0;
+    QEMUIOVector hd_qiov;
+    int ret = 0;
+
+    qemu_iovec_init(&hd_qiov, qiov->niov);
+
+    while (nb_sectors > 0) {
+        int64_t position;
+        int n, nbytes;
+
+        qemu_co_mutex_lock(&s->lock);
+        position = seek_to_sector(s, sector_num);
+        qemu_co_mutex_unlock(&s->lock);
+
+        n = cluster_remainder(s, sector_num, nb_sectors);
+        nbytes = n << BDRV_SECTOR_BITS;
+
+        if (position < 0) {
+            qemu_iovec_memset(qiov, bytes_done, 0, nbytes);
+        } else {
+            qemu_iovec_reset(&hd_qiov);
+            qemu_iovec_concat(&hd_qiov, qiov, bytes_done, nbytes);
+
+            ret = bdrv_co_readv(bs->file, position, n, &hd_qiov);
+            if (ret < 0) {
+                break;
+            }
+        }
+
+        nb_sectors -= n;
+        sector_num += n;
+        bytes_done += nbytes;
+    }
+
+    qemu_iovec_destroy(&hd_qiov);
     return ret;
 }
 
@@ -201,8 +243,9 @@ static BlockDriver bdrv_parallels = {
     .instance_size     = sizeof(BDRVParallelsState),
     .bdrv_probe                = parallels_probe,
     .bdrv_open         = parallels_open,
-    .bdrv_read          = parallels_co_read,
     .bdrv_close                = parallels_close,
+    .bdrv_co_get_block_status = parallels_co_get_block_status,
+    .bdrv_co_readv  = parallels_co_readv,
 };
 
 static void bdrv_parallels_init(void)