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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: Frédéric Danis <frederic.danis@collabora.com>
Acked-by: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
This commit is contained in:
Frédéric Danis 2022-01-25 18:14:05 +01:00 committed by Richard Weinberger
parent b35507a4cf
commit d2a0a616ab
3 changed files with 17 additions and 1 deletions
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8
arch/um/drivers/ubd_kern.c
View File

@ -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;

1
arch/um/include/shared/os.h
View File

@ -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);

9
arch/um/os-Linux/file.c
View File

@ -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);