This is a note to let you know that I've just added the patch titled
dm thin: switch to read-only mode if metadata space is exhausted
to the 3.12-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-switch-to-read-only-mode-if-metadata-space-is-exhausted.patch
and it can be found in the queue-3.12 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 4a02b34e0cf1d0d0dd3737702841da4bf615a50a Mon Sep 17 00:00:00 2001
From: Mike Snitzer <snitzer@xxxxxxxxxx>
Date: Tue, 3 Dec 2013 12:20:57 -0500
Subject: dm thin: switch to read-only mode if metadata space is exhausted
From: Mike Snitzer <snitzer@xxxxxxxxxx>
commit 4a02b34e0cf1d0d0dd3737702841da4bf615a50a upstream.
Switch the thin pool to read-only mode in alloc_data_block() if
dm_pool_alloc_data_block() fails because the pool's metadata space is
exhausted.
Differentiate between data and metadata space in messages about no
free space available.
This issue was noticed with the device-mapper-test-suite using:
dmtest run --suite thin-provisioning -n /exhausting_metadata_space_causes_fail_mode/
The quantity of errors logged in this case must be reduced.
before patch:
device-mapper: thin: 253:4: reached low water mark for metadata device: sending event.
device-mapper: space map metadata: unable to allocate new metadata block
device-mapper: space map common: dm_tm_shadow_block() failed
device-mapper: space map metadata: unable to allocate new metadata block
device-mapper: space map common: dm_tm_shadow_block() failed
device-mapper: space map metadata: unable to allocate new metadata block
device-mapper: space map common: dm_tm_shadow_block() failed
device-mapper: space map metadata: unable to allocate new metadata block
device-mapper: space map common: dm_tm_shadow_block() failed
device-mapper: space map metadata: unable to allocate new metadata block
device-mapper: space map common: dm_tm_shadow_block() failed
<snip ... these repeat for a _very_ long while ... >
device-mapper: space map metadata: unable to allocate new metadata block
device-mapper: thin: 253:4: commit failed: error = -28
device-mapper: thin: 253:4: switching pool to read-only mode
after patch:
device-mapper: thin: 253:4: reached low water mark for metadata device: sending event.
device-mapper: space map metadata: unable to allocate new metadata block
device-mapper: thin: 253:4: no free metadata space available.
device-mapper: thin: 253:4: switching pool to read-only mode
Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx>
Acked-by: Joe Thornber <ejt@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/md/dm-thin.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)
--- a/drivers/md/dm-thin.c
+++ b/drivers/md/dm-thin.c
@@ -959,7 +959,7 @@ static int alloc_data_block(struct thin_
* table reload).
*/
if (!free_blocks) {
- DMWARN("%s: no free space available.",
+ DMWARN("%s: no free data space available.",
dm_device_name(pool->pool_md));
spin_lock_irqsave(&pool->lock, flags);
pool->no_free_space = 1;
@@ -969,8 +969,16 @@ static int alloc_data_block(struct thin_
}
r = dm_pool_alloc_data_block(pool->pmd, result);
- if (r)
+ if (r) {
+ if (r == -ENOSPC &&
+ !dm_pool_get_free_metadata_block_count(pool->pmd, &free_blocks) &&
+ !free_blocks) {
+ DMWARN("%s: no free metadata space available.",
+ dm_device_name(pool->pool_md));
+ set_pool_mode(pool, PM_READ_ONLY);
+ }
return r;
+ }
return 0;
}
Patches currently in stable-queue which might be from snitzer@xxxxxxxxxx are
queue-3.12/dm-array-fix-a-reference-counting-bug-in-shadow_ablock.patch
queue-3.12/dm-thin-always-fallback-the-pool-mode-if-commit-fails.patch
queue-3.12/dm-table-fail-dm_table_create-on-dm_round_up-overflow.patch
queue-3.12/dm-stats-initialize-read-only-module-parameter.patch
queue-3.12/dm-thin-allow-pool-in-read-only-mode-to-transition-to-read-write-mode.patch
queue-3.12/dm-space-map-metadata-return-on-failure-in-sm_metadata_new_block.patch
queue-3.12/dm-bufio-initialize-read-only-module-parameters.patch
queue-3.12/dm-snapshot-avoid-snapshot-space-leak-on-crash.patch
queue-3.12/dm-thin-re-establish-read-only-state-when-switching-to-fail-mode.patch
queue-3.12/dm-delay-fix-a-possible-deadlock-due-to-shared-workqueue.patch
queue-3.12/dm-thin-switch-to-read-only-mode-if-a-mapping-insert-fails.patch
queue-3.12/dm-thin-switch-to-read-only-mode-if-metadata-space-is-exhausted.patch
queue-3.12/dm-space-map-disallow-decrementing-a-reference-count-below-zero.patch
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