| From | Greg Kroah-Hartman <> | Subject | [PATCH 3.12 089/118] dm thin: switch to read-only mode if metadata space is exhausted | Date | Wed, 18 Dec 2013 13:12:06 -0800 |
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3.12-stable review patch. If anyone has any objections, please let me know.
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From: Mike Snitzer <snitzer@redhat.com>
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@redhat.com> Acked-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- 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; }
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