raw-posix: add discard support
Add support to discard blocks in a raw image residing on an XFS filesystem
by calling the XFS_IOC_UNRESVSP64 ioctl to punch holes. Support for other
hole punching mechanisms can be added when they become available.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
diff --git a/block/raw-posix.c b/block/raw-posix.c
index 9286fb8..6b72470 100644
--- a/block/raw-posix.c
+++ b/block/raw-posix.c
@@ -69,6 +69,10 @@
#include <sys/diskslice.h>
#endif
+#ifdef CONFIG_XFS
+#include <xfs/xfs.h>
+#endif
+
//#define DEBUG_FLOPPY
//#define DEBUG_BLOCK
@@ -120,6 +124,9 @@
#endif
uint8_t *aligned_buf;
unsigned aligned_buf_size;
+#ifdef CONFIG_XFS
+ bool is_xfs : 1;
+#endif
} BDRVRawState;
static int fd_open(BlockDriverState *bs);
@@ -196,6 +203,12 @@
#endif
}
+#ifdef CONFIG_XFS
+ if (platform_test_xfs_fd(s->fd)) {
+ s->is_xfs = 1;
+ }
+#endif
+
return 0;
out_free_buf:
@@ -740,6 +753,37 @@
return qemu_fdatasync(s->fd);
}
+#ifdef CONFIG_XFS
+static int xfs_discard(BDRVRawState *s, int64_t sector_num, int nb_sectors)
+{
+ struct xfs_flock64 fl;
+
+ memset(&fl, 0, sizeof(fl));
+ fl.l_whence = SEEK_SET;
+ fl.l_start = sector_num << 9;
+ fl.l_len = (int64_t)nb_sectors << 9;
+
+ if (xfsctl(NULL, s->fd, XFS_IOC_UNRESVSP64, &fl) < 0) {
+ DEBUG_BLOCK_PRINT("cannot punch hole (%s)\n", strerror(errno));
+ return -errno;
+ }
+
+ return 0;
+}
+#endif
+
+static int raw_discard(BlockDriverState *bs, int64_t sector_num, int nb_sectors)
+{
+#ifdef CONFIG_XFS
+ BDRVRawState *s = bs->opaque;
+
+ if (s->is_xfs) {
+ return xfs_discard(s, sector_num, nb_sectors);
+ }
+#endif
+
+ return 0;
+}
static QEMUOptionParameter raw_create_options[] = {
{
@@ -761,6 +805,7 @@
.bdrv_close = raw_close,
.bdrv_create = raw_create,
.bdrv_flush = raw_flush,
+ .bdrv_discard = raw_discard,
.bdrv_aio_readv = raw_aio_readv,
.bdrv_aio_writev = raw_aio_writev,
