This patch adds a new option preallocation for raw format, and implements
full preallocation.
Signed-off-by: Hu Tao <hu...@cn.fujitsu.com>
---
block/raw-posix.c | 46 ++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 46 insertions(+)
diff --git a/block/raw-posix.c b/block/raw-posix.c
index 6f6b8c1..a722d27 100644
--- a/block/raw-posix.c
+++ b/block/raw-posix.c
@@ -1160,17 +1160,52 @@ static int64_t
raw_get_allocated_file_size(BlockDriverState *bs)
return (int64_t)st.st_blocks * 512;
}
+#ifdef __linux__
+static int raw_preallocate2(int fd, int64_t offset, int64_t length)
+{
+ int ret = -1;
+
+ ret = fallocate(fd, 0, offset, length);
+ if (ret < 0) {
+ ret = -errno;
+ }
+
+ /* fallback to posix_fallocate() if fallocate() is not supported */
+ if (ret == -ENOSYS || ret == -EOPNOTSUPP) {
+ ret = posix_fallocate(fd, offset, length);
+ }
+
+ return ret;
+}
+#else
+static int raw_preallocate2(int fd, int64_t offset, int64_t length)
+{
+ return posix_fallocate(fd, offset, length);
+}
+#endif
+
static int raw_create(const char *filename, QEMUOptionParameter *options,
Error **errp)
{
int fd;
int result = 0;
int64_t total_size = 0;
+ PreallocMode prealloc = PREALLOC_MODE_OFF;
/* Read out options */
while (options && options->name) {
if (!strcmp(options->name, BLOCK_OPT_SIZE)) {
total_size = options->value.n & BDRV_SECTOR_MASK;
+ } else if (!strcmp(options->name, BLOCK_OPT_PREALLOC)) {
+ if (!options->value.s || !strcmp(options->value.s, "off")) {
+ prealloc = PREALLOC_MODE_OFF;
+ } else if (!strcmp(options->value.s, "full")) {
+ prealloc = PREALLOC_MODE_FULL;
+ } else {
+ error_setg(errp, "Invalid preallocation mode: '%s'",
+ options->value.s);
+ return -EINVAL;
+ }
}
options++;
}
@@ -1185,6 +1220,12 @@ static int raw_create(const char *filename,
QEMUOptionParameter *options,
result = -errno;
error_setg_errno(errp, -result, "Could not resize file");
}
+ if (prealloc == PREALLOC_MODE_FULL) {
+ result = raw_preallocate2(fd, 0, total_size);
+ if (result != 0)
+ error_setg_errno(errp, -result,
+ "Could not preallocate data for the new
file");
+ }
if (qemu_close(fd) != 0) {
result = -errno;
error_setg_errno(errp, -result, "Could not close the new file");
@@ -1340,6 +1381,11 @@ static QEMUOptionParameter raw_create_options[] = {
.type = OPT_SIZE,
.help = "Virtual disk size"
},
+ {
+ .name = BLOCK_OPT_PREALLOC,
+ .type = OPT_STRING,
+ .help = "Preallocation mode (allowed values: off, full)"
+ },
{ NULL }
};
--
1.7.11.7
