[md PATCH 12/15] md: factor out set_in_sync()

NeilBrown
2017-03-15T03:05:14Z

Three separate places in md.c check if the number of active
writes is zero and, if so, sets mddev->in_sync.

There are a few differences, but there shouldn't be:
- it is always appropriate to notify the change in
sysfs_state, and there is no need to do this outside a
spin-locked region.
- we never need to check ->recovery_cp. The state of resync
is not relevant for whether there are any pending writes
or not (which is what ->in_sync reports).

So create set_in_sync() which does the correct tests and
makes the correct changes, and call this in all three
places.

Any behaviour changes here a minor and cosmetic.

Signed-off-by: NeilBrown <neilb@suse.com>
---
drivers/md/md.c | 54 ++++++++++++++++++++----------------------------------
1 file changed, 20 insertions(+), 34 deletions(-)

diff --git a/drivers/md/md.c b/drivers/md/md.c
index bad5771bced4..2fa8048894e6 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -2252,6 +2252,21 @@ static void export_array(struct mddev *mddev)
mddev->major_version = 0;
}

+static bool set_in_sync(struct mddev *mddev)
+{
+ WARN_ON_ONCE(!spin_is_locked(&mddev->lock));
+ if (atomic_read(&mddev->writes_pending) == 0) {
+ if (mddev->in_sync == 0) {
+ mddev->in_sync = 1;
+ set_bit(MD_SB_CHANGE_CLEAN, &mddev->sb_flags);
+ sysfs_notify_dirent_safe(mddev->sysfs_state);
+ }
+ }
+ if (mddev->safemode == 1)
+ mddev->safemode = 0;
+ return mddev->in_sync;
+}
+
static void sync_sbs(struct mddev *mddev, int nospares)
{
/* Update each superblock (in-memory image), but
@@ -4024,7 +4039,7 @@ static int restart_array(struct mddev *mddev);
static ssize_t
array_state_store(struct mddev *mddev, const char *buf, size_t len)
{
- int err;
+ int err = 0;
enum array_state st = match_word(buf, array_states);

if (mddev->pers && (st == active || st == clean) && mddev->ro != 1) {
@@ -4037,18 +4052,9 @@ array_state_store(struct mddev *mddev, const char *buf, size_t len)
clear_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags);
md_wakeup_thread(mddev->thread);
wake_up(&mddev->sb_wait);
- err = 0;
} else /* st == clean */ {
restart_array(mddev);
- if (atomic_read(&mddev->writes_pending) == 0) {
- if (mddev->in_sync == 0) {
- mddev->in_sync = 1;
- if (mddev->safemode == 1)
- mddev->safemode = 0;
- set_bit(MD_SB_CHANGE_CLEAN, &mddev->sb_flags);
- }
- err = 0;
- } else
+ if (!set_in_sync(mddev))
err = -EBUSY;
}
if (!err)
@@ -4106,15 +4112,7 @@ array_state_store(struct mddev *mddev, const char *buf, size_t len)
if (err)
break;
spin_lock(&mddev->lock);
- if (atomic_read(&mddev->writes_pending) == 0) {
- if (mddev->in_sync == 0) {
- mddev->in_sync = 1;
- if (mddev->safemode == 1)
- mddev->safemode = 0;
- set_bit(MD_SB_CHANGE_CLEAN, &mddev->sb_flags);
- }
- err = 0;
- } else
+ if (!set_in_sync(mddev))
err = -EBUSY;
spin_unlock(&mddev->lock);
} else
@@ -8591,22 +8589,10 @@ void md_check_recovery(struct mddev *mddev)
}
}

- if (!mddev->external) {
- int did_change = 0;
+ if (!mddev->external && !mddev->in_sync) {
spin_lock(&mddev->lock);
- if (mddev->safemode &&
- !atomic_read(&mddev->writes_pending) &&
- !mddev->in_sync &&
- mddev->recovery_cp == MaxSector) {
- mddev->in_sync = 1;
- did_change = 1;
- set_bit(MD_SB_CHANGE_CLEAN, &mddev->sb_flags);
- }
- if (mddev->safemode == 1)
- mddev->safemode = 0;
+ set_in_sync(mddev);
spin_unlock(&mddev->lock);
- if (did_change)
- sysfs_notify_dirent_safe(mddev->sysfs_state);
}

if (mddev->sb_flags)