This is a note to let you know that I've just added the patch titled
dm thin: fix to consistently zero-fill reads to unprovisioned blocks
to the 3.19-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
dm-thin-fix-to-consistently-zero-fill-reads-to-unprovisioned-blocks.patch
and it can be found in the queue-3.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 5f027a3bf184d1d36e68745f7cd3718a8b879cc0 Mon Sep 17 00:00:00 2001
From: Joe Thornber <ejt@xxxxxxxxxx>
Date: Fri, 27 Feb 2015 14:09:12 +0000
Subject: dm thin: fix to consistently zero-fill reads to unprovisioned blocks
From: Joe Thornber <ejt@xxxxxxxxxx>
commit 5f027a3bf184d1d36e68745f7cd3718a8b879cc0 upstream.
It was always intended that a read to an unprovisioned block will return
zeroes regardless of whether the pool is in read-only or read-write
mode. thin_bio_map() was inconsistent with its handling of such reads
when the pool is in read-only mode, it now properly zero-fills the bios
it returns in response to unprovisioned block reads.
Eliminate thin_bio_map()'s special read-only mode handling of -ENODATA
and just allow the IO to be deferred to the worker which will result in
pool->process_bio() handling the IO (which already properly zero-fills
reads to unprovisioned blocks).
Reported-by: Eric Sandeen <sandeen@xxxxxxxxxx>
Signed-off-by: Joe Thornber <ejt@xxxxxxxxxx>
Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/md/dm-thin.c | 11 -----------
1 file changed, 11 deletions(-)
--- a/drivers/md/dm-thin.c
+++ b/drivers/md/dm-thin.c
@@ -2357,17 +2357,6 @@ static int thin_bio_map(struct dm_target
return DM_MAPIO_REMAPPED;
case -ENODATA:
- if (get_pool_mode(tc->pool) == PM_READ_ONLY) {
- /*
- * This block isn't provisioned, and we have no way
- * of doing so.
- */
- handle_unserviceable_bio(tc->pool, bio);
- cell_defer_no_holder(tc, virt_cell);
- return DM_MAPIO_SUBMITTED;
- }
- /* fall through */
-
case -EWOULDBLOCK:
thin_defer_cell(tc, virt_cell);
return DM_MAPIO_SUBMITTED;
Patches currently in stable-queue which might be from ejt@xxxxxxxxxx are
queue-3.19/dm-thin-fix-to-consistently-zero-fill-reads-to-unprovisioned-blocks.patch
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