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authorStefan Hajnoczi <stefanha@linux.vnet.ibm.com>2012-02-07 13:27:25 +0000
committerKevin Wolf <kwolf@redhat.com>2012-02-09 16:17:50 +0100
commitf08f2ddae078e8a7683f8b16da8e0cc3029c7b89 (patch)
treebfb375876998a1c425ce6bb018dcd923118b7aea /trace-events
parent1a6d39fd71ddf90c5b76026cac4d5ff51fbaf8d8 (diff)
block: add .bdrv_co_write_zeroes() interface
The ability to zero regions of an image file is a useful primitive for higher-level features such as image streaming or zero write detection. Image formats may support an optimized metadata representation instead of writing zeroes into the image file. This allows zero writes to be potentially faster than regular write operations and also preserve sparseness of the image file. The .bdrv_co_write_zeroes() interface should be implemented by block drivers that wish to provide efficient zeroing. Note that this operation is different from the discard operation, which may leave the contents of the region indeterminate. That means discarded blocks are not guaranteed to contain zeroes and may contain junk data instead. Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Diffstat (limited to 'trace-events')
-rw-r--r--trace-events1
1 files changed, 1 insertions, 0 deletions
diff --git a/trace-events b/trace-events
index 5d0574964..3372087ed 100644
--- a/trace-events
+++ b/trace-events
@@ -67,6 +67,7 @@ bdrv_lock_medium(void *bs, bool locked) "bs %p locked %d"
bdrv_co_readv(void *bs, int64_t sector_num, int nb_sector) "bs %p sector_num %"PRId64" nb_sectors %d"
bdrv_co_copy_on_readv(void *bs, int64_t sector_num, int nb_sector) "bs %p sector_num %"PRId64" nb_sectors %d"
bdrv_co_writev(void *bs, int64_t sector_num, int nb_sector) "bs %p sector_num %"PRId64" nb_sectors %d"
+bdrv_co_write_zeroes(void *bs, int64_t sector_num, int nb_sector) "bs %p sector_num %"PRId64" nb_sectors %d"
bdrv_co_io_em(void *bs, int64_t sector_num, int nb_sectors, int is_write, void *acb) "bs %p sector_num %"PRId64" nb_sectors %d is_write %d acb %p"
bdrv_co_do_copy_on_readv(void *bs, int64_t sector_num, int nb_sectors, int64_t cluster_sector_num, int cluster_nb_sectors) "bs %p sector_num %"PRId64" nb_sectors %d cluster_sector_num %"PRId64" cluster_nb_sectors %d"