From 2214c260c72b0bd94e6c1c19bf451686212025d3 Mon Sep 17 00:00:00 2001 From: Artur Paszkiewicz Date: Mon, 8 May 2017 11:56:55 +0200 Subject: md: don't return -EAGAIN in md_allow_write for external metadata arrays This essentially reverts commit b5470dc5fc18 ("md: resolve external metadata handling deadlock in md_allow_write") with some adjustments. Since commit 6791875e2e53 ("md: make reconfig_mutex optional for writes to md sysfs files.") changing array_state to 'active' does not use mddev_lock() and will not cause a deadlock with md_allow_write(). This revert simplifies userspace tools that write to sysfs attributes like "stripe_cache_size" or "consistency_policy" because it removes the need for special handling for external metadata arrays, checking for EAGAIN and retrying the write. Signed-off-by: Artur Paszkiewicz Signed-off-by: Shaohua Li --- drivers/md/md.c | 20 ++++++++------------ 1 file changed, 8 insertions(+), 12 deletions(-) (limited to 'drivers/md/md.c') diff --git a/drivers/md/md.c b/drivers/md/md.c index 82f798be964f..10367ffe92e3 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -8022,18 +8022,15 @@ EXPORT_SYMBOL(md_write_end); * may proceed without blocking. It is important to call this before * attempting a GFP_KERNEL allocation while holding the mddev lock. * Must be called with mddev_lock held. - * - * In the ->external case MD_SB_CHANGE_PENDING can not be cleared until mddev->lock - * is dropped, so return -EAGAIN after notifying userspace. */ -int md_allow_write(struct mddev *mddev) +void md_allow_write(struct mddev *mddev) { if (!mddev->pers) - return 0; + return; if (mddev->ro) - return 0; + return; if (!mddev->pers->sync_request) - return 0; + return; spin_lock(&mddev->lock); if (mddev->in_sync) { @@ -8046,13 +8043,12 @@ int md_allow_write(struct mddev *mddev) spin_unlock(&mddev->lock); md_update_sb(mddev, 0); sysfs_notify_dirent_safe(mddev->sysfs_state); + /* wait for the dirty state to be recorded in the metadata */ + wait_event(mddev->sb_wait, + !test_bit(MD_SB_CHANGE_CLEAN, &mddev->sb_flags) && + !test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags)); } else spin_unlock(&mddev->lock); - - if (test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags)) - return -EAGAIN; - else - return 0; } EXPORT_SYMBOL_GPL(md_allow_write); -- cgit v1.2.3-59-g8ed1b