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authorNeilBrown <neilb@suse.de>2011-02-24 17:26:41 +1100
committerNeilBrown <neilb@suse.de>2011-02-24 17:26:41 +1100
commitf0b4f7e2f29af678bd9af43422c537dcb6008603 (patch)
treedfc2aa18bbf8411a499ef8117a5e15490eb44728 /drivers/md/md.h
parent93b270f76e7ef3b81001576860c2701931cdc78b (diff)
md: Fix - again - partition detection when array becomes active
Revert b821eaa572fd737faaf6928ba046e571526c36c6 and f3b99be19ded511a1bf05a148276239d9f13eefa When I wrote the first of these I had a wrong idea about the lifetime of 'struct block_device'. It can disappear at any time that the block device is not open if it falls out of the inode cache. So relying on the 'size' recorded with it to detect when the device size has changed and so we need to revalidate, is wrong. Rather, we really do need the 'changed' attribute stored directly in the mddev and set/tested as appropriate. Without this patch, a sequence of: mknod / open / close / unlink (which can cause a block_device to be created and then destroyed) will result in a rescan of the partition table and consequence removal and addition of partitions. Several of these in a row can get udev racing to create and unlink and other code can get confused. With the patch, the rescan is only performed when needed and so there are no races. This is suitable for any stable kernel from 2.6.35. Reported-by: "Wojcik, Krzysztof" <krzysztof.wojcik@intel.com> Signed-off-by: NeilBrown <neilb@suse.de> Cc: stable@kernel.org
Diffstat (limited to 'drivers/md/md.h')
-rw-r--r--drivers/md/md.h2
1 files changed, 2 insertions, 0 deletions
diff --git a/drivers/md/md.h b/drivers/md/md.h
index 7e90b8593b2a..12215d437fcc 100644
--- a/drivers/md/md.h
+++ b/drivers/md/md.h
@@ -274,6 +274,8 @@ struct mddev_s
atomic_t active; /* general refcount */
atomic_t openers; /* number of active opens */
+ int changed; /* True if we might need to
+ * reread partition info */
int degraded; /* whether md should consider
* adding a spare
*/