The patch titled
md: avoid backward event updates in md superblock when degraded.
has been added to the -mm tree. Its filename is
md-avoid-backward-event-updates-in-md-superblock-when-degraded.patch
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: md: avoid backward event updates in md superblock when degraded.
From: NeilBrown <neilb@xxxxxxx>
If we
- shut down a clean array,
- restart with one (or more) drive(s) missing
- make some changes
- pause, so that they array gets marked 'clean',
the event count on the superblock of included drives
will be the same as that of the removed drives.
So adding the removed drive back in will cause it
to be included with no resync.
To avoid this, we only update the eventcount backwards when the array
is not degraded. In this case there can (should) be no non-connected
drives that we can get confused with, and this is the particular case
where updating-backwards is valuable.
Signed-off-by: Neil Brown <neilb@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
drivers/md/md.c | 13 +++++++++++++
1 files changed, 13 insertions(+)
diff -puN drivers/md/md.c~md-avoid-backward-event-updates-in-md-superblock-when-degraded drivers/md/md.c
--- a/drivers/md/md.c~md-avoid-backward-event-updates-in-md-superblock-when-degraded
+++ a/drivers/md/md.c
@@ -1597,6 +1597,19 @@ void md_update_sb(mddev_t * mddev)
repeat:
spin_lock_irq(&mddev->write_lock);
+
+ if (mddev->degraded && mddev->sb_dirty == 3)
+ /* If the array is degraded, then skipping spares is both
+ * dangerous and fairly pointless.
+ * Dangerous because a device that was removed from the array
+ * might have a event_count that still looks up-to-date,
+ * so it can be re-added without a resync.
+ * Pointless because if there are any spares to skip,
+ * then a recovery will happen and soon that array won't
+ * be degraded any more and the spare can go back to sleep then.
+ */
+ mddev->sb_dirty = 1;
+
sync_req = mddev->in_sync;
mddev->utime = get_seconds();
if (mddev->sb_dirty == 3)
_
Patches currently in -mm which might be from neilb@xxxxxxx are
lockdep-fix-blkdev_open-warning.patch
md-avoid-backward-event-updates-in-md-superblock-when-degraded.patch
vfs-destroy-the-dentries-contributed-by-a-superblock-on-unmounting.patch
knfsd-knfsd-add-some-missing-newlines-in-printks.patch
knfsd-knfsd-remove-an-unused-variable-from-e_show.patch
knfsd-knfsd-remove-an-unused-variable-from-auth_unix_lookup.patch
knfsd-add-a-callback-for-when-last-rpc-thread-finishes.patch
knfsd-add-a-callback-for-when-last-rpc-thread-finishes-tidy.patch
knfsd-be-more-selective-in-which-sockets-lockd-listens-on.patch
knfsd-remove-nfsd_versbits-as-intermediate-storage-for-desired-versions.patch
knfsd-separate-out-some-parts-of-nfsd_svc-which-start-nfs-servers.patch
knfsd-separate-out-some-parts-of-nfsd_svc-which-start-nfs-servers-tweaks.patch
knfsd-define-new-nfsdfs-file-portlist-contains-list-of-ports.patch
knfsd-define-new-nfsdfs-file-portlist-contains-list-of-ports-tidy.patch
knfsd-define-new-nfsdfs-file-portlist-contains-list-of-ports-fix.patch
knfsd-allow-sockets-to-be-passed-to-nfsd-via-portlist.patch
knfsd-use-seq_start_token-instead-of-hardcoded-magic-void1.patch
knfsd-have-ext2-reject-file-handles-with-bad-inode-numbers-early.patch
knfsd-have-ext2-reject-file-handles-with-bad-inode-numbers-early-tidy.patch
knfsd-make-ext3-reject-filehandles-referring-to-invalid-inode-numbers.patch
knfsd-make-ext3-reject-filehandles-referring-to-invalid-inode-numbers-tidy.patch
knfsd-drop-serv-option-to-svc_recv-and-svc_process.patch
knfsd-drop-serv-option-to-svc_recv-and-svc_process-nfs-callback-fix-nfs-callback-fix.patch
knfsd-check-return-value-of-lockd_up-in-write_ports.patch
knfsd-move-makesock-failed-warning-into-make_socks.patch
knfsd-correctly-handle-error-condition-from-lockd_up.patch
knfsd-move-tempsock-aging-to-a-timer.patch
knfsd-move-tempsock-aging-to-a-timer-tidy.patch
knfsd-convert-sk_inuse-to-atomic_t.patch
knfsd-use-new-lock-for-svc_sock-deferred-list.patch
knfsd-convert-sk_reserved-to-atomic_t.patch
knfsd-test-and-set-sk_busy-atomically.patch
knfsd-split-svc_serv-into-pools.patch
knfsd-split-svc_serv-into-pools-fix.patch
knfsd-add-svc_get.patch
knfsd-add-svc_set_num_threads.patch
knfsd-use-svc_set_num_threads-to-manage-threads-in-knfsd.patch
knfsd-make-rpc-threads-pools-numa-aware.patch
knfsd-make-rpc-threads-pools-numa-aware-fix.patch
knfsd-allow-admin-to-set-nthreads-per-node.patch
nfsd-lockdep-annotation.patch
knfsd-nfsd-lockdep-annotation-fix.patch
knfsd-call-lockd_down-when-closing-a-socket-via-a-write-to-nfsd-portlist.patch
knfsd-protect-update-to-sn_nrthreads-with-lock_kernel.patch
knfsd-fixed-handling-of-lockd-fail-when-adding-nfsd-socket.patch
knfsd-replace-two-page-lists-in-struct-svc_rqst-with-one.patch
knfsd-avoid-excess-stack-usage-in-svc_tcp_recvfrom.patch
knfsd-prepare-knfsd-for-support-of-rsize-wsize-of-up-to-1mb-over-tcp.patch
knfsd-allow-max-size-of-nfsd-payload-to-be-configured.patch
knfsd-make-nfsd-readahead-params-cache-smp-friendly.patch
knfsd-knfsd-cache-ipmap-per-tcp-socket.patch
md-the-scheduled-removal-of-the-start_array-ioctl-for-md.patch
md-fix-a-comment-that-is-wrong-in-raid5h.patch
md-factor-out-part-of-raid1d-into-a-separate-function.patch
md-factor-out-part-of-raid10d-into-a-separate-function.patch
md-replace-magic-numbers-in-sb_dirty-with-well-defined-bit-flags.patch
md-remove-the-working_disks-and-failed_disks-from-raid5-state-data.patch
md-remove-working_disks-from-raid10-state.patch
md-remove-working_disks-from-raid1-state-data.patch
md-improve-locking-around-error-handling.patch
md-dm-reduce-stack-usage-with-stacked-block-devices.patch
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