* [PATCH] zbd: Fix zone report handling
@ 2019-04-19 3:40 Damien Le Moal
2019-04-19 15:11 ` Jens Axboe
0 siblings, 1 reply; 2+ messages in thread
From: Damien Le Moal @ 2019-04-19 3:40 UTC (permalink / raw)
To: fio, Jens Axboe; +Cc: Shinichiro Kawasaki
fio may be executed concurrently with a block device revalidation by
the kernel. Device revalidation may lead to the block device capacity
to be changed to a smaller value (device changed) or to even 0 in case
of revalidation failure. In such case, the BLKREPORTZONE ioctl
executed from read_zone_info() may report a success with an empty zone
report when the start sector for the report is above the new capacity
of the device. This leads to an infinite loop inside parse_zone_info()
and the fio run never terminating.
Fix this problem by returning -EIO from read_zone_info() thus
avoiding the infinite loop in parse_zone_info(). This change does not
affect the normal case with a stable device as read_zone_info() is
always called with a valid start sector that does not result in an
empty zone report.
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
---
zbd.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)
diff --git a/zbd.c b/zbd.c
index 2da742b7..1c46b452 100644
--- a/zbd.c
+++ b/zbd.c
@@ -186,11 +186,14 @@ static bool zbd_verify_bs(void)
* size of @buf.
*
* Returns 0 upon success and a negative error code upon failure.
+ * If the zone report is empty, always assume an error (device problem) and
+ * return -EIO.
*/
static int read_zone_info(int fd, uint64_t start_sector,
void *buf, unsigned int bufsz)
{
struct blk_zone_report *hdr = buf;
+ int ret;
if (bufsz < sizeof(*hdr))
return -EINVAL;
@@ -199,7 +202,12 @@ static int read_zone_info(int fd, uint64_t start_sector,
hdr->nr_zones = (bufsz - sizeof(*hdr)) / sizeof(struct blk_zone);
hdr->sector = start_sector;
- return ioctl(fd, BLKREPORTZONE, hdr) >= 0 ? 0 : -errno;
+ ret = ioctl(fd, BLKREPORTZONE, hdr);
+ if (ret)
+ return -errno;
+ if (!hdr->nr_zones)
+ return -EIO;
+ return 0;
}
/*
--
2.20.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] zbd: Fix zone report handling
2019-04-19 3:40 [PATCH] zbd: Fix zone report handling Damien Le Moal
@ 2019-04-19 15:11 ` Jens Axboe
0 siblings, 0 replies; 2+ messages in thread
From: Jens Axboe @ 2019-04-19 15:11 UTC (permalink / raw)
To: Damien Le Moal, fio; +Cc: Shinichiro Kawasaki
On 4/18/19 9:40 PM, Damien Le Moal wrote:
> fio may be executed concurrently with a block device revalidation by
> the kernel. Device revalidation may lead to the block device capacity
> to be changed to a smaller value (device changed) or to even 0 in case
> of revalidation failure. In such case, the BLKREPORTZONE ioctl
> executed from read_zone_info() may report a success with an empty zone
> report when the start sector for the report is above the new capacity
> of the device. This leads to an infinite loop inside parse_zone_info()
> and the fio run never terminating.
>
> Fix this problem by returning -EIO from read_zone_info() thus
> avoiding the infinite loop in parse_zone_info(). This change does not
> affect the normal case with a stable device as read_zone_info() is
> always called with a valid start sector that does not result in an
> empty zone report.
Applied, thanks.
--
Jens Axboe
^ permalink raw reply [flat|nested] 2+ messages in thread
end of thread, other threads:[~2019-04-19 15:11 UTC | newest]
Thread overview: 2+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-04-19 3:40 [PATCH] zbd: Fix zone report handling Damien Le Moal
2019-04-19 15:11 ` Jens Axboe
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.