diff options
author | Stefan Hajnoczi <stefanha@redhat.com> | 2013-06-24 17:13:10 +0200 |
---|---|---|
committer | Kevin Wolf <kwolf@redhat.com> | 2013-06-28 09:20:26 +0200 |
commit | d616b224745b2c522f965cf8de7da17b553b959a (patch) | |
tree | df5c6f5b8e13823d4c202782eec90c93b55997a6 /block.c | |
parent | 5dae8e5fb803f53fadc116cefe353953b938cbe1 (diff) | |
download | qemu-d616b224745b2c522f965cf8de7da17b553b959a.zip qemu-d616b224745b2c522f965cf8de7da17b553b959a.tar.gz qemu-d616b224745b2c522f965cf8de7da17b553b959a.tar.bz2 |
block: add bdrv_add_before_write_notifier()
The bdrv_add_before_write_notifier() function installs a callback that
is invoked before a write request is processed. This will be used to
implement copy-on-write point-in-time snapshots where we need to copy
out old data before overwriting it.
Note that BdrvTrackedRequest is moved to block_int.h since it is passed
to .notify() functions.
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Diffstat (limited to 'block.c')
-rw-r--r-- | block.c | 23 |
1 files changed, 12 insertions, 11 deletions
@@ -305,6 +305,7 @@ BlockDriverState *bdrv_new(const char *device_name) } bdrv_iostatus_disable(bs); notifier_list_init(&bs->close_notifiers); + notifier_with_return_list_init(&bs->before_write_notifiers); return bs; } @@ -1840,16 +1841,6 @@ int bdrv_commit_all(void) return 0; } -struct BdrvTrackedRequest { - BlockDriverState *bs; - int64_t sector_num; - int nb_sectors; - bool is_write; - QLIST_ENTRY(BdrvTrackedRequest) list; - Coroutine *co; /* owner, used for deadlock detection */ - CoQueue wait_queue; /* coroutines blocked on this request */ -}; - /** * Remove an active request from the tracked requests list * @@ -2620,7 +2611,11 @@ static int coroutine_fn bdrv_co_do_writev(BlockDriverState *bs, tracked_request_begin(&req, bs, sector_num, nb_sectors, true); - if (flags & BDRV_REQ_ZERO_WRITE) { + ret = notifier_with_return_list_notify(&bs->before_write_notifiers, &req); + + if (ret < 0) { + /* Do nothing, write notifier decided to fail this request */ + } else if (flags & BDRV_REQ_ZERO_WRITE) { ret = bdrv_co_do_write_zeroes(bs, sector_num, nb_sectors); } else { ret = drv->bdrv_co_writev(bs, sector_num, nb_sectors, qiov); @@ -4581,3 +4576,9 @@ AioContext *bdrv_get_aio_context(BlockDriverState *bs) /* Currently BlockDriverState always uses the main loop AioContext */ return qemu_get_aio_context(); } + +void bdrv_add_before_write_notifier(BlockDriverState *bs, + NotifierWithReturn *notifier) +{ + notifier_with_return_list_add(&bs->before_write_notifiers, notifier); +} |