Commit d2a0a616 authored by Frédéric Danis's avatar Frédéric Danis Committed by Richard Weinberger
Browse files

um: Fix WRITE_ZEROES in the UBD Driver 



Call to fallocate with FALLOC_FL_PUNCH_HOLE on a device backed by a sparse
file can end up by missing data, zeroes data range, if the underlying file
is used with a tool like bmaptool which will referenced only used spaces.

Signed-off-by: default avatarFrédéric Danis <frederic.danis@collabora.com>
Acked-by: default avatarAnton Ivanov <anton.ivanov@cambridgegreys.com>
Signed-off-by: default avatarRichard Weinberger <richard@nod.at>
parent b35507a4

arch/um/drivers/ubd_kern.c

+7 −1
Original line number Diff line number Diff line
@@ -1526,13 +1526,19 @@ static void do_io(struct io_thread_req *req, struct io_desc *desc) 
			}

			break;

		case REQ_OP_DISCARD:

		case REQ_OP_WRITE_ZEROES:

			n = os_falloc_punch(req->fds[bit], off, len);

			if (n) {

				req->error = map_error(-n);

				return;

			}

			break;

		case REQ_OP_WRITE_ZEROES:

			n = os_falloc_zeroes(req->fds[bit], off, len);

			if (n) {

				req->error = map_error(-n);

				return;

			}

			break;

		default:

			WARN_ON_ONCE(1);

			req->error = BLK_STS_NOTSUPP;

arch/um/include/shared/os.h

+1 −0
Original line number Diff line number Diff line
@@ -168,6 +168,7 @@ extern unsigned os_major(unsigned long long dev); 
extern unsigned os_minor(unsigned long long dev);

extern unsigned long long os_makedev(unsigned major, unsigned minor);

extern int os_falloc_punch(int fd, unsigned long long offset, int count);

extern int os_falloc_zeroes(int fd, unsigned long long offset, int count);

extern int os_eventfd(unsigned int initval, int flags);

extern int os_sendmsg_fds(int fd, const void *buf, unsigned int len,

			  const int *fds, unsigned int fds_num);

arch/um/os-Linux/file.c

+9 −0
Original line number Diff line number Diff line
@@ -625,6 +625,15 @@ int os_falloc_punch(int fd, unsigned long long offset, int len) 
	return n;

}



int os_falloc_zeroes(int fd, unsigned long long offset, int len)

{

	int n = fallocate(fd, FALLOC_FL_ZERO_RANGE|FALLOC_FL_KEEP_SIZE, offset, len);



	if (n < 0)

		return -errno;

	return n;

}



int os_eventfd(unsigned int initval, int flags)

{

	int fd = eventfd(initval, flags);