dm-devel.redhat.com archive mirror
 help / color / mirror / Atom feed
From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Sasha Levin <sashal@kernel.org>, Joe Thornber <ejt@redhat.com>,
	dm-devel@redhat.com, Mike Snitzer <snitzer@redhat.com>
Subject: [dm-devel] [PATCH AUTOSEL 5.13 074/189] dm space maps: don't reset space map allocation cursor when committing
Date: Tue,  6 Jul 2021 07:12:14 -0400	[thread overview]
Message-ID: <20210706111409.2058071-74-sashal@kernel.org> (raw)
In-Reply-To: <20210706111409.2058071-1-sashal@kernel.org>

From: Joe Thornber <ejt@redhat.com>

[ Upstream commit 5faafc77f7de69147d1e818026b9a0cbf036a7b2 ]

Current commit code resets the place where the search for free blocks
will begin back to the start of the metadata device.  There are a couple
of repercussions to this:

- The first allocation after the commit is likely to take longer than
  normal as it searches for a free block in an area that is likely to
  have very few free blocks (if any).

- Any free blocks it finds will have been recently freed.  Reusing them
  means we have fewer old copies of the metadata to aid recovery from
  hardware error.

Fix these issues by leaving the cursor alone, only resetting when the
search hits the end of the metadata device.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/md/persistent-data/dm-space-map-disk.c     | 9 ++++++++-
 drivers/md/persistent-data/dm-space-map-metadata.c | 9 ++++++++-
 2 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/drivers/md/persistent-data/dm-space-map-disk.c b/drivers/md/persistent-data/dm-space-map-disk.c
index 61f56909e00b..4f8069bb0481 100644
--- a/drivers/md/persistent-data/dm-space-map-disk.c
+++ b/drivers/md/persistent-data/dm-space-map-disk.c
@@ -171,6 +171,14 @@ static int sm_disk_new_block(struct dm_space_map *sm, dm_block_t *b)
 	 * Any block we allocate has to be free in both the old and current ll.
 	 */
 	r = sm_ll_find_common_free_block(&smd->old_ll, &smd->ll, smd->begin, smd->ll.nr_blocks, b);
+	if (r == -ENOSPC) {
+		/*
+		 * There's no free block between smd->begin and the end of the metadata device.
+		 * We search before smd->begin in case something has been freed.
+		 */
+		r = sm_ll_find_common_free_block(&smd->old_ll, &smd->ll, 0, smd->begin, b);
+	}
+
 	if (r)
 		return r;
 
@@ -194,7 +202,6 @@ static int sm_disk_commit(struct dm_space_map *sm)
 		return r;
 
 	memcpy(&smd->old_ll, &smd->ll, sizeof(smd->old_ll));
-	smd->begin = 0;
 	smd->nr_allocated_this_transaction = 0;
 
 	return 0;
diff --git a/drivers/md/persistent-data/dm-space-map-metadata.c b/drivers/md/persistent-data/dm-space-map-metadata.c
index 9e3c64ec2026..da439ac85796 100644
--- a/drivers/md/persistent-data/dm-space-map-metadata.c
+++ b/drivers/md/persistent-data/dm-space-map-metadata.c
@@ -452,6 +452,14 @@ static int sm_metadata_new_block_(struct dm_space_map *sm, dm_block_t *b)
 	 * Any block we allocate has to be free in both the old and current ll.
 	 */
 	r = sm_ll_find_common_free_block(&smm->old_ll, &smm->ll, smm->begin, smm->ll.nr_blocks, b);
+	if (r == -ENOSPC) {
+		/*
+		 * There's no free block between smm->begin and the end of the metadata device.
+		 * We search before smm->begin in case something has been freed.
+		 */
+		r = sm_ll_find_common_free_block(&smm->old_ll, &smm->ll, 0, smm->begin, b);
+	}
+
 	if (r)
 		return r;
 
@@ -503,7 +511,6 @@ static int sm_metadata_commit(struct dm_space_map *sm)
 		return r;
 
 	memcpy(&smm->old_ll, &smm->ll, sizeof(smm->old_ll));
-	smm->begin = 0;
 	smm->allocated_this_transaction = 0;
 
 	return 0;
-- 
2.30.2

--
dm-devel mailing list
dm-devel@redhat.com
https://listman.redhat.com/mailman/listinfo/dm-devel


       reply	other threads:[~2021-07-06 11:16 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20210706111409.2058071-1-sashal@kernel.org>
2021-07-06 11:12 ` Sasha Levin [this message]
2021-07-06 11:12 ` [dm-devel] [PATCH AUTOSEL 5.13 075/189] dm writecache: don't split bios when overwriting contiguous cache content Sasha Levin
2021-07-06 11:12 ` [dm-devel] [PATCH AUTOSEL 5.13 076/189] dm: Fix dm_accept_partial_bio() relative to zone management commands Sasha Levin
2021-07-06 11:12 ` [dm-devel] [PATCH AUTOSEL 5.13 106/189] dm writecache: commit just one block, not a full page Sasha Levin

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20210706111409.2058071-74-sashal@kernel.org \
    --to=sashal@kernel.org \
    --cc=dm-devel@redhat.com \
    --cc=ejt@redhat.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=snitzer@redhat.com \
    --cc=stable@vger.kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).