Commit 2214c260 authored by Artur Paszkiewicz's avatar Artur Paszkiewicz Committed by Shaohua Li
Browse files

md: don't return -EAGAIN in md_allow_write for external metadata arrays 



This essentially reverts commit b5470dc5 ("md: resolve external
metadata handling deadlock in md_allow_write") with some adjustments.

Since commit 6791875e ("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: default avatarArtur Paszkiewicz <artur.paszkiewicz@intel.com>
Signed-off-by: default avatarShaohua Li <shli@fb.com>
parent 3d05f3ae

drivers/md/md.c

+8 −12
Original line number Diff line number Diff line
@@ -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);

drivers/md/md.h

+1 −1
Original line number Diff line number Diff line
@@ -665,7 +665,7 @@ extern int sync_page_io(struct md_rdev *rdev, sector_t sector, int size, 
			bool metadata_op);

extern void md_do_sync(struct md_thread *thread);

extern void md_new_event(struct mddev *mddev);

extern int md_allow_write(struct mddev *mddev);

extern void md_allow_write(struct mddev *mddev);

extern void md_wait_for_blocked_rdev(struct md_rdev *rdev, struct mddev *mddev);

extern void md_set_array_sectors(struct mddev *mddev, sector_t array_sectors);

extern int md_check_no_bitmap(struct mddev *mddev);

drivers/md/raid1.c

+3 −6
Original line number Diff line number Diff line
@@ -3197,7 +3197,7 @@ static int raid1_reshape(struct mddev *mddev) 
	struct r1conf *conf = mddev->private;

	int cnt, raid_disks;

	unsigned long flags;

	int d, d2, err;

	int d, d2;



	/* Cannot change chunk_size, layout, or level */

	if (mddev->chunk_sectors != mddev->new_chunk_sectors ||
@@ -3209,11 +3209,8 @@ static int raid1_reshape(struct mddev *mddev) 
		return -EINVAL;

	}



	if (!mddev_is_clustered(mddev)) {

		err = md_allow_write(mddev);

		if (err)

			return err;

	}

	if (!mddev_is_clustered(mddev))

		md_allow_write(mddev);



	raid_disks = mddev->raid_disks + mddev->delta_disks;

drivers/md/raid5.c

+3 −9
Original line number Diff line number Diff line
@@ -2309,14 +2309,12 @@ static int resize_stripes(struct r5conf *conf, int newsize) 
	struct stripe_head *osh, *nsh;

	LIST_HEAD(newstripes);

	struct disk_info *ndisks;

	int err;

	int err = 0;

	struct kmem_cache *sc;

	int i;

	int hash, cnt;



	err = md_allow_write(conf->mddev);

	if (err)

		return err;

	md_allow_write(conf->mddev);



	/* Step 1 */

	sc = kmem_cache_create(conf->cache_name[1-conf->active_name],
@@ -6310,7 +6308,6 @@ int 
raid5_set_cache_size(struct mddev *mddev, int size)

{

	struct r5conf *conf = mddev->private;

	int err;



	if (size <= 16 || size > 32768)

		return -EINVAL;
@@ -6322,10 +6319,7 @@ raid5_set_cache_size(struct mddev *mddev, int size) 
		;

	mutex_unlock(&conf->cache_size_mutex);





	err = md_allow_write(mddev);

	if (err)

		return err;

	md_allow_write(mddev);



	mutex_lock(&conf->cache_size_mutex);

	while (size > conf->max_nr_stripes)

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