linux/drivers/md/raid0.c, branch v4.1

md/raid0: fix restore to sector variable in raid0_make_request

2015-05-20T23:14:25Z

The variable "sector" in "raid0_make_request()" was improperly updated by a call to "sector_div()" which modifies its first argument in place. Commit 47d68979cc968535cb87f3e5f2e6a3533ea48fbd restored this variable after the call for later re-use. Unfortunetly the restore was done after the referenced variable "bio" was advanced. This lead to the original value and the restored value being different. Here we move this line to the proper place. One observed side effect of this bug was discarding a file though unlinking would cause an unrelated file's contents to be discarded. Signed-off-by: NeilBrown Fixes: 47d68979cc96 ("md/raid0: fix bug with chunksize not a power of 2.") Cc: stable@vger.kernel.org (any that received above backport) URL: https://bugzilla.kernel.org/show_bug.cgi?id=98501

md-raid0: conditional mddev->queue access to suit dm-raid

2015-05-08T08:39:40Z

This patch is a prerequisite for dm-raid "raid0" support to allow dm-raid to access the MD RAID0 personality doing unconditional accesses to mddev->queue, which is NULL in case of dm-raid stacked on top of MD. Most of the conditional mddev->queue accesses made it to upstream but this missing one, which prohibits md raid0 to set disk stack limits (being done in dm core in case of md underneath dm). Signed-off-by: Heinz Mauelshagen Tested-by: Heinz Mauelshagen Signed-off-by: NeilBrown

md raid0: access mddev->queue (request queue member) conditionally because it is not set when accessed from dm-raid

2015-04-21T22:00:41Z

The patch makes 3 references to mddev->queue in the raid0 personality conditional in order to allow for it to be accessed from dm-raid. Mandatory, because md instances underneath dm-raid don't manage a request queue of their own which'd lead to oopses without the patch. Signed-off-by: Heinz Mauelshagen Tested-by: Heinz Mauelshagen Signed-off-by: NeilBrown

md/raid0: fix bug with chunksize not a power of 2.

2015-04-10T05:36:31Z

Since commit 20d0189b1012a37d2533a87fb451f7852f2418d1 in v3.14-rc1 RAID0 has performed incorrect calculations when the chunksize is not a power of 2. This happens because "sector_div()" modifies its first argument, but this wasn't taken into account in the patch. So restore that first arg before re-using the variable. Reported-by: Joe Landman Reported-by: Dave Chinner Fixes: 20d0189b1012a37d2533a87fb451f7852f2418d1 Cc: stable@vger.kernel.org (3.14 and later). Signed-off-by: NeilBrown

md: fix problems with freeing private data after ->run failure.

2015-03-20T22:40:36Z

If ->run() fails, it can either free the data structures it allocated, or leave that task to ->free() which will be called on failures. However: md.c calls ->free() even if ->private_data is NULL, which causes problems in some personalities. raid0.c frees the data, but doesn't clear ->private_data, which will become a problem when we fix md.c So better fix both these issues at once. Reported-by: Richard W.M. Jones Fixes: 5aa61f427e4979be733e4847b9199ff9cc48a47e URL: https://bugzilla.kernel.org/show_bug.cgi?id=94381 Signed-off-by: NeilBrown

md: rename ->stop to ->free

2015-02-03T21:35:52Z

Now that the ->stop function only frees the private data, rename is accordingly. Also pass in the private pointer as an arg rather than using mddev->private. This flexibility will be useful in level_store(). Finally, don't clear ->private. It doesn't make sense to clear it seeing that isn't what we free, and it is no longer necessary to clear ->private (it was some time ago before ->to_remove was introduced). Setting ->to_remove in ->free() is a bit of a wart, but not a big problem at the moment. Signed-off-by: NeilBrown

md: split detach operation out from ->stop.

2015-02-03T21:35:52Z

Each md personality has a 'stop' operation which does two things: 1/ it finalizes some aspects of the array to ensure nothing is accessing the ->private data 2/ it frees the ->private data. All the steps in '1' can apply to all arrays and so can be performed in common code. This is useful as in the case where we change the personality which manages an array (in level_store()), it would be helpful to do step 1 early, and step 2 later. So split the 'step 1' functionality out into a new mddev_detach(). Signed-off-by: NeilBrown

md: make merge_bvec_fn more robust in face of personality changes.

2015-02-03T21:35:52Z

There is no locking around calls to merge_bvec_fn(), so it is possible that calls which coincide with a level (or personality) change could go wrong. So create a central dispatch point for these functions and use rcu_read_lock(). If the array is suspended, reject any merge that can be rejected. If not, we know it is safe to call the function. Signed-off-by: NeilBrown

md: make ->congested robust against personality changes.

2015-02-03T21:35:52Z

There is currently no locking around calls to the 'congested' bdi function. If called at an awkward time while an array is being converted from one level (or personality) to another, there is a tiny chance of running code in an unreferenced module etc. So add a 'congested' function to the md_personality operations structure, and call it with appropriate locking from a central 'mddev_congested'. When the array personality is changing the array will be 'suspended' so no IO is processed. If mddev_congested detects this, it simply reports that the array is congested, which is a safe guess. As mddev_suspend calls synchronize_rcu(), mddev_congested can avoid races by included the whole call inside an rcu_read_lock() region. This require that the congested functions for all subordinate devices can be run under rcu_lock. Fortunately this is the case. Signed-off-by: NeilBrown

md: remove unwanted white space from md.c

2014-10-14T02:08:29Z

My editor shows much of this is RED. Signed-off-by: NeilBrown