qed: Make qiov match request size until backing file EOF

[mirror_qemu.git] / block / vpc.c

diff --git a/block/vpc.c b/block/vpc.c
index 2e25f572309974db2a93fe29268fceedb807b3dd..8b376a40be98acce4448e498b366ee3cd91d96db 100644 (file)
--- a/block/vpc.c
+++ b/block/vpc.c
@@ -29,6 +29,13 @@
 #if defined(CONFIG_UUID)
 #include <uuid/uuid.h>
 #endif
+#ifdef __linux__
+#include <linux/fs.h>
+#include <sys/ioctl.h>
+#ifndef FS_NOCOW_FL
+#define FS_NOCOW_FL                     0x00800000 /* Do not cow file */
+#endif
+#endif
 
 /**************************************************************/
 
@@ -738,12 +745,11 @@ static int create_fixed_disk(int fd, uint8_t *buf, int64_t total_size)
     return ret;
 }
 
-static int vpc_create(const char *filename, QEMUOptionParameter *options,
-                      Error **errp)
+static int vpc_create(const char *filename, QemuOpts *opts, Error **errp)
 {
     uint8_t buf[1024];
     VHDFooter *footer = (VHDFooter *) buf;
-    QEMUOptionParameter *disk_type_param;
+    char *disk_type_param;
     int fd, i;
     uint16_t cyls = 0;
     uint8_t heads = 0;
@@ -752,27 +758,45 @@ static int vpc_create(const char *filename, QEMUOptionParameter *options,
     int64_t total_size;
     int disk_type;
     int ret = -EIO;
+    bool nocow = false;
 
     /* Read out options */
-    total_size = get_option_parameter(options, BLOCK_OPT_SIZE)->value.n;
-
-    disk_type_param = get_option_parameter(options, BLOCK_OPT_SUBFMT);
-    if (disk_type_param && disk_type_param->value.s) {
-        if (!strcmp(disk_type_param->value.s, "dynamic")) {
+    total_size = qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0);
+    disk_type_param = qemu_opt_get_del(opts, BLOCK_OPT_SUBFMT);
+    if (disk_type_param) {
+        if (!strcmp(disk_type_param, "dynamic")) {
             disk_type = VHD_DYNAMIC;
-        } else if (!strcmp(disk_type_param->value.s, "fixed")) {
+        } else if (!strcmp(disk_type_param, "fixed")) {
             disk_type = VHD_FIXED;
         } else {
-            return -EINVAL;
+            ret = -EINVAL;
+            goto out;
         }
     } else {
         disk_type = VHD_DYNAMIC;
     }
+    nocow = qemu_opt_get_bool_del(opts, BLOCK_OPT_NOCOW, false);
 
     /* Create the file */
     fd = qemu_open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY, 0644);
     if (fd < 0) {
-        return -EIO;
+        ret = -EIO;
+        goto out;
+    }
+
+    if (nocow) {
+#ifdef __linux__
+        /* Set NOCOW flag to solve performance issue on fs like btrfs.
+         * This is an optimisation. The FS_IOC_SETFLAGS ioctl return value will
+         * be ignored since any failure of this operation should not block the
+         * left work.
+         */
+        int attr;
+        if (ioctl(fd, FS_IOC_GETFLAGS, &attr) == 0) {
+            attr |= FS_NOCOW_FL;
+            ioctl(fd, FS_IOC_SETFLAGS, &attr);
+        }
+#endif
     }
 
     /*
@@ -837,8 +861,10 @@ static int vpc_create(const char *filename, QEMUOptionParameter *options,
         ret = create_fixed_disk(fd, buf, total_size);
     }
 
- fail:
+fail:
     qemu_close(fd);
+out:
+    g_free(disk_type_param);
     return ret;
 }
 
@@ -866,20 +892,29 @@ static void vpc_close(BlockDriverState *bs)
     error_free(s->migration_blocker);
 }
 
-static QEMUOptionParameter vpc_create_options[] = {
-    {
-        .name = BLOCK_OPT_SIZE,
-        .type = OPT_SIZE,
-        .help = "Virtual disk size"
-    },
-    {
-        .name = BLOCK_OPT_SUBFMT,
-        .type = OPT_STRING,
-        .help =
-            "Type of virtual hard disk format. Supported formats are "
-            "{dynamic (default) | fixed} "
-    },
-    { NULL }
+static QemuOptsList vpc_create_opts = {
+    .name = "vpc-create-opts",
+    .head = QTAILQ_HEAD_INITIALIZER(vpc_create_opts.head),
+    .desc = {
+        {
+            .name = BLOCK_OPT_SIZE,
+            .type = QEMU_OPT_SIZE,
+            .help = "Virtual disk size"
+        },
+        {
+            .name = BLOCK_OPT_SUBFMT,
+            .type = QEMU_OPT_STRING,
+            .help =
+                "Type of virtual hard disk format. Supported formats are "
+                "{dynamic (default) | fixed} "
+        },
+        {
+            .name = BLOCK_OPT_NOCOW,
+            .type = QEMU_OPT_BOOL,
+            .help = "Turn off copy-on-write (valid only on btrfs)"
+        },
+        { /* end of list */ }
+    }
 };
 
 static BlockDriver bdrv_vpc = {
@@ -897,7 +932,7 @@ static BlockDriver bdrv_vpc = {
 
     .bdrv_get_info          = vpc_get_info,
 
-    .create_options         = vpc_create_options,
+    .create_opts            = &vpc_create_opts,
     .bdrv_has_zero_init     = vpc_has_zero_init,
 };