block: Introduce blk_set_allow_write_beyond_eof()

We check that the guest can't write beyond the end of its disk, but for
other internal users it can make sense to allow growing a file.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Kevin Wolf 2016-03-08 16:39:49 +01:00
parent 6340472c54
commit c10c9d9615
2 changed files with 17 additions and 7 deletions

View File

@ -50,6 +50,8 @@ struct BlockBackend {
bool iostatus_enabled;
BlockDeviceIoStatus iostatus;
bool allow_write_beyond_eof;
NotifierList remove_bs_notifiers, insert_bs_notifiers;
};
@ -579,6 +581,11 @@ void blk_iostatus_set_err(BlockBackend *blk, int error)
}
}
void blk_set_allow_write_beyond_eof(BlockBackend *blk, bool allow)
{
blk->allow_write_beyond_eof = allow;
}
static int blk_check_byte_request(BlockBackend *blk, int64_t offset,
size_t size)
{
@ -592,17 +599,19 @@ static int blk_check_byte_request(BlockBackend *blk, int64_t offset,
return -ENOMEDIUM;
}
len = blk_getlength(blk);
if (len < 0) {
return len;
}
if (offset < 0) {
return -EIO;
}
if (offset > len || len - offset < size) {
return -EIO;
if (!blk->allow_write_beyond_eof) {
len = blk_getlength(blk);
if (len < 0) {
return len;
}
if (offset > len || len - offset < size) {
return -EIO;
}
}
return 0;

View File

@ -78,6 +78,7 @@ void blk_insert_bs(BlockBackend *blk, BlockDriverState *bs);
void blk_hide_on_behalf_of_hmp_drive_del(BlockBackend *blk);
void blk_set_allow_write_beyond_eof(BlockBackend *blk, bool allow);
void blk_iostatus_enable(BlockBackend *blk);
bool blk_iostatus_is_enabled(const BlockBackend *blk);
BlockDeviceIoStatus blk_iostatus(const BlockBackend *blk);