* [PATCH] Btrfs: fix regression in raid level conversion
@ 2015-05-20 14:13 Chris Mason
2015-05-20 17:02 ` David Sterba
0 siblings, 1 reply; 3+ messages in thread
From: Chris Mason @ 2015-05-20 14:13 UTC (permalink / raw)
To: linux-btrfs; +Cc: holger.hoffstaette
Commit 2f0810880f082fa8ba66ab2c33b02e4ff9770a5e changed
btrfs_set_block_group_ro to avoid trying to allocate new chunks with the
new raid profile during conversion. This fixed failures when there was
no space on the drive to allocate a new chunk, but the metadata
reserves were sufficient to continue the conversion.
But this ended up causing a regression when the drive had plenty of
space to allocate new chunks, mostly because reduce_alloc_profile isn't
using the new raid profile.
Fixing btrfs_reduce_alloc_profile is a bigger patch. For now, do a
partial revert of 2f0810880, and don't error out if we hit ENOSPC.
Signed-off-by: Chris Mason <clm@fb.com>
---
fs/btrfs/extent-tree.c | 20 ++++++++++++++++++++
1 file changed, 20 insertions(+)
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 45e3f08..a115599 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -8829,6 +8829,26 @@ again:
goto again;
}
+ /*
+ * if we are changing raid levels, try to allocate a corresponding
+ * block group with the new raid level.
+ */
+ if (!(cache->flags & BTRFS_BLOCK_GROUP_SYSTEM)) {
+ alloc_flags = update_block_group_flags(root, cache->flags);
+ if (alloc_flags != cache->flags) {
+ ret = do_chunk_alloc(trans, root, alloc_flags,
+ CHUNK_ALLOC_FORCE);
+ /*
+ * ENOSPC is allowed here, we may have enough space
+ * already allocated at the new raid level to
+ * carry on
+ */
+ if (ret == -ENOSPC)
+ ret = 0;
+ if (ret < 0)
+ goto out;
+ }
+ }
ret = set_block_group_ro(cache, 0);
if (!ret)
--
2.4.0
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] Btrfs: fix regression in raid level conversion
2015-05-20 14:13 [PATCH] Btrfs: fix regression in raid level conversion Chris Mason
@ 2015-05-20 17:02 ` David Sterba
2015-05-20 18:08 ` Chris Mason
0 siblings, 1 reply; 3+ messages in thread
From: David Sterba @ 2015-05-20 17:02 UTC (permalink / raw)
To: Chris Mason, linux-btrfs, holger.hoffstaette
On Wed, May 20, 2015 at 10:13:11AM -0400, Chris Mason wrote:
> Commit 2f0810880f082fa8ba66ab2c33b02e4ff9770a5e changed
> btrfs_set_block_group_ro to avoid trying to allocate new chunks with the
> new raid profile during conversion. This fixed failures when there was
> no space on the drive to allocate a new chunk, but the metadata
> reserves were sufficient to continue the conversion.
>
> But this ended up causing a regression when the drive had plenty of
> space to allocate new chunks, mostly because reduce_alloc_profile isn't
> using the new raid profile.
>
> Fixing btrfs_reduce_alloc_profile is a bigger patch. For now, do a
> partial revert of 2f0810880, and don't error out if we hit ENOSPC.
>
> Signed-off-by: Chris Mason <clm@fb.com>
> ---
> fs/btrfs/extent-tree.c | 20 ++++++++++++++++++++
> 1 file changed, 20 insertions(+)
>
> diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
> index 45e3f08..a115599 100644
> --- a/fs/btrfs/extent-tree.c
> +++ b/fs/btrfs/extent-tree.c
> @@ -8829,6 +8829,26 @@ again:
> goto again;
> }
>
> + /*
> + * if we are changing raid levels, try to allocate a corresponding
> + * block group with the new raid level.
> + */
> + if (!(cache->flags & BTRFS_BLOCK_GROUP_SYSTEM)) {
This prevents to switch the system chunk in all cases. What was the
reason to do it?
If I remove the check, then the conversions work in all combinations.
Eg.
* convert from ext (or use any single device fs)
* add second device
* balance data/metadata/system to raid1
* all fine
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] Btrfs: fix regression in raid level conversion
2015-05-20 17:02 ` David Sterba
@ 2015-05-20 18:08 ` Chris Mason
0 siblings, 0 replies; 3+ messages in thread
From: Chris Mason @ 2015-05-20 18:08 UTC (permalink / raw)
To: dsterba, linux-btrfs, holger.hoffstaette
On 05/20/2015 01:02 PM, David Sterba wrote:
> On Wed, May 20, 2015 at 10:13:11AM -0400, Chris Mason wrote:
>> Commit 2f0810880f082fa8ba66ab2c33b02e4ff9770a5e changed
>> btrfs_set_block_group_ro to avoid trying to allocate new chunks with the
>> new raid profile during conversion. This fixed failures when there was
>> no space on the drive to allocate a new chunk, but the metadata
>> reserves were sufficient to continue the conversion.
>>
>> But this ended up causing a regression when the drive had plenty of
>> space to allocate new chunks, mostly because reduce_alloc_profile isn't
>> using the new raid profile.
>>
>> Fixing btrfs_reduce_alloc_profile is a bigger patch. For now, do a
>> partial revert of 2f0810880, and don't error out if we hit ENOSPC.
>>
>> Signed-off-by: Chris Mason <clm@fb.com>
>> ---
>> fs/btrfs/extent-tree.c | 20 ++++++++++++++++++++
>> 1 file changed, 20 insertions(+)
>>
>> diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
>> index 45e3f08..a115599 100644
>> --- a/fs/btrfs/extent-tree.c
>> +++ b/fs/btrfs/extent-tree.c
>> @@ -8829,6 +8829,26 @@ again:
>> goto again;
>> }
>>
>> + /*
>> + * if we are changing raid levels, try to allocate a corresponding
>> + * block group with the new raid level.
>> + */
>> + if (!(cache->flags & BTRFS_BLOCK_GROUP_SYSTEM)) {
>
> This prevents to switch the system chunk in all cases. What was the
> reason to do it?
I thought the system chunk was being caught by check_system_chunk below,
but no, its using the wrong profile. It did work when I tested, but I
ran it a few times in a row and got inconsistent results.
>
> If I remove the check, then the conversions work in all combinations.
> Eg.
Thanks, I'm pushing out an updated patch without the check.
-chris
^ permalink raw reply [flat|nested] 3+ messages in thread
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2015-05-20 14:13 [PATCH] Btrfs: fix regression in raid level conversion Chris Mason
2015-05-20 17:02 ` David Sterba
2015-05-20 18:08 ` Chris Mason
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