On Sun, Jul 31 2016, shli@xxxxxxxxxx wrote:
> From: Shaohua Li <shli@xxxxxx>
>
> Changing the location changes a lot of things. Holding the lock to avoid race.
> This makes the .quiesce called with mddev lock hold too.
>
> Cc: NeilBrown <neilb@xxxxxxxx>
> Signed-off-by: Shaohua Li <shli@xxxxxx>
Acked-by: NeilBrown <neilb@xxxxxxxx>
Yes, I think this is justified. As you say, location_store is a fairly
significant change.
Thanks,
NeilBrown
> ---
> drivers/md/bitmap.c | 47 +++++++++++++++++++++++++++++++++--------------
> 1 file changed, 33 insertions(+), 14 deletions(-)
>
> diff --git a/drivers/md/bitmap.c b/drivers/md/bitmap.c
> index 6fff794..13041ee 100644
> --- a/drivers/md/bitmap.c
> +++ b/drivers/md/bitmap.c
> @@ -2183,19 +2183,29 @@ location_show(struct mddev *mddev, char *page)
> static ssize_t
> location_store(struct mddev *mddev, const char *buf, size_t len)
> {
> + int rv;
>
> + rv = mddev_lock(mddev);
> + if (rv)
> + return rv;
> if (mddev->pers) {
> - if (!mddev->pers->quiesce)
> - return -EBUSY;
> - if (mddev->recovery || mddev->sync_thread)
> - return -EBUSY;
> + if (!mddev->pers->quiesce) {
> + rv = -EBUSY;
> + goto out;
> + }
> + if (mddev->recovery || mddev->sync_thread) {
> + rv = -EBUSY;
> + goto out;
> + }
> }
>
> if (mddev->bitmap || mddev->bitmap_info.file ||
> mddev->bitmap_info.offset) {
> /* bitmap already configured. Only option is to clear it */
> - if (strncmp(buf, "none", 4) != 0)
> - return -EBUSY;
> + if (strncmp(buf, "none", 4) != 0) {
> + rv = -EBUSY;
> + goto out;
> + }
> if (mddev->pers) {
> mddev->pers->quiesce(mddev, 1);
> bitmap_destroy(mddev);
> @@ -2214,21 +2224,25 @@ location_store(struct mddev *mddev, const char *buf, size_t len)
> /* nothing to be done */;
> else if (strncmp(buf, "file:", 5) == 0) {
> /* Not supported yet */
> - return -EINVAL;
> + rv = -EINVAL;
> + goto out;
> } else {
> - int rv;
> if (buf[0] == '+')
> rv = kstrtoll(buf+1, 10, &offset);
> else
> rv = kstrtoll(buf, 10, &offset);
> if (rv)
> - return rv;
> - if (offset == 0)
> - return -EINVAL;
> + goto out;
> + if (offset == 0) {
> + rv = -EINVAL;
> + goto out;
> + }
> if (mddev->bitmap_info.external == 0 &&
> mddev->major_version == 0 &&
> - offset != mddev->bitmap_info.default_offset)
> - return -EINVAL;
> + offset != mddev->bitmap_info.default_offset) {
> + rv = -EINVAL;
> + goto out;
> + }
> mddev->bitmap_info.offset = offset;
> if (mddev->pers) {
> struct bitmap *bitmap;
> @@ -2245,7 +2259,7 @@ location_store(struct mddev *mddev, const char *buf, size_t len)
> mddev->pers->quiesce(mddev, 0);
> if (rv) {
> bitmap_destroy(mddev);
> - return rv;
> + goto out;
> }
> }
> }
> @@ -2257,6 +2271,11 @@ location_store(struct mddev *mddev, const char *buf, size_t len)
> set_bit(MD_CHANGE_DEVS, &mddev->flags);
> md_wakeup_thread(mddev->thread);
> }
> + rv = 0;
> +out:
> + mddev_unlock(mddev);
> + if (rv)
> + return rv;
> return len;
> }
>
> --
> 2.7.4
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