* [PATCH v2] btrfs: qgroup: Fix wrong parameter order for trace events
@ 2019-10-17 2:23 Qu Wenruo
2019-10-17 2:40 ` Qu WenRuo
0 siblings, 1 reply; 2+ messages in thread
From: Qu Wenruo @ 2019-10-17 2:23 UTC (permalink / raw)
To: linux-btrfs, linux-kernel, linux-trace-devel
[BUG]
For btrfs:qgroup_meta_reserve event, the trace event can output garbage:
qgroup_meta_reserve: 9c7f6acc-b342-4037-bc47-7f6e4d2232d7: refroot=5(FS_TREE) type=DATA diff=2
qgroup_meta_reserve: 9c7f6acc-b342-4037-bc47-7f6e4d2232d7: refroot=5(FS_TREE) type=0x258792 diff=2
Since we're in qgroup_meta_reserve() trace event, the @type should never
be DATA, while diff must be aligned to sectorsize (4K in this case).
Only UUID and refroot is correct.
[CAUSE]
There are two causes for this bug:
- Bad parameter order
For trace event btrfs:qgroup_meta_reserve, we're passing wrong
parameters.
The correct parameters are:
struct btrfs_root, s64 diff, int type.
However the used order is:
struct btrfs_root, int type, s64 diff.
- @type is not even assigned
What I was doing !? /facepalm
[FIX]
Fix the super stupid bug.
Now everything works fine:
qgroup_meta_reserve: 0477ad60-9aeb-4040-8a03-1900844d46ba: refroot=5(FS_TREE) type=META_PERTRANS diff=81920
qgroup_meta_reserve: 0477ad60-9aeb-4040-8a03-1900844d46ba: refroot=5(FS_TREE) type=META_PREALLOC diff=16384
qgroup_meta_reserve: 0477ad60-9aeb-4040-8a03-1900844d46ba: refroot=5(FS_TREE) type=META_PREALLOC diff=0
qgroup_meta_reserve: 0477ad60-9aeb-4040-8a03-1900844d46ba: refroot=5(FS_TREE) type=META_PREALLOC diff=16384
qgroup_meta_reserve: 0477ad60-9aeb-4040-8a03-1900844d46ba: refroot=5(FS_TREE) type=META_PREALLOC diff=-16384
qgroup_meta_reserve: 0477ad60-9aeb-4040-8a03-1900844d46ba: refroot=5(FS_TREE) type=META_PREALLOC diff=16384
qgroup_meta_reserve: 0477ad60-9aeb-4040-8a03-1900844d46ba: refroot=5(FS_TREE) type=META_PREALLOC diff=-16384
qgroup_meta_reserve: 0477ad60-9aeb-4040-8a03-1900844d46ba: refroot=5(FS_TREE) type=META_PREALLOC diff=16384
qgroup_meta_reserve: 0477ad60-9aeb-4040-8a03-1900844d46ba: refroot=5(FS_TREE) type=META_PREALLOC diff=-16384
Fixes: 4ee0d8832c2e ("btrfs: qgroup: Update trace events for metadata reservation")
Signed-off-by: Qu Wenruo <wqu@suse.com>
---
Changelog:
v2:
- Use more accurate comment about the fintuning options
- Use more elegant method to output uuid
---
fs/btrfs/qgroup.c | 4 ++--
include/trace/events/btrfs.h | 1 +
2 files changed, 3 insertions(+), 2 deletions(-)
diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c
index c4bb69941c77..3ad151655eb8 100644
--- a/fs/btrfs/qgroup.c
+++ b/fs/btrfs/qgroup.c
@@ -3629,7 +3629,7 @@ int __btrfs_qgroup_reserve_meta(struct btrfs_root *root, int num_bytes,
return 0;
BUG_ON(num_bytes != round_down(num_bytes, fs_info->nodesize));
- trace_qgroup_meta_reserve(root, type, (s64)num_bytes);
+ trace_qgroup_meta_reserve(root, (s64)num_bytes, type);
ret = qgroup_reserve(root, num_bytes, enforce, type);
if (ret < 0)
return ret;
@@ -3676,7 +3676,7 @@ void __btrfs_qgroup_free_meta(struct btrfs_root *root, int num_bytes,
*/
num_bytes = sub_root_meta_rsv(root, num_bytes, type);
BUG_ON(num_bytes != round_down(num_bytes, fs_info->nodesize));
- trace_qgroup_meta_reserve(root, type, -(s64)num_bytes);
+ trace_qgroup_meta_reserve(root, -(s64)num_bytes, type);
btrfs_qgroup_free_refroot(fs_info, root->root_key.objectid,
num_bytes, type);
}
diff --git a/include/trace/events/btrfs.h b/include/trace/events/btrfs.h
index 5df604de4f11..0ebcaa153f93 100644
--- a/include/trace/events/btrfs.h
+++ b/include/trace/events/btrfs.h
@@ -1710,6 +1710,7 @@ TRACE_EVENT(qgroup_meta_reserve,
TP_fast_assign_btrfs(root->fs_info,
__entry->refroot = root->root_key.objectid;
__entry->diff = diff;
+ __entry->type = type;
),
TP_printk_btrfs("refroot=%llu(%s) type=%s diff=%lld",
--
2.23.0
^ permalink raw reply related [flat|nested] 2+ messages in thread* Re: [PATCH v2] btrfs: qgroup: Fix wrong parameter order for trace events
2019-10-17 2:23 [PATCH v2] btrfs: qgroup: Fix wrong parameter order for trace events Qu Wenruo
@ 2019-10-17 2:40 ` Qu WenRuo
0 siblings, 0 replies; 2+ messages in thread
From: Qu WenRuo @ 2019-10-17 2:40 UTC (permalink / raw)
To: linux-btrfs, linux-kernel, linux-trace-devel
[-- Attachment #1.1: Type: text/plain, Size: 4015 bytes --]
Please discard this patch.
It's sent out by accident.
The correct one is only sent to btrfs mail list.
Thanks,
Qu
On 2019/10/17 上午10:23, Qu Wenruo wrote:
> [BUG]
> For btrfs:qgroup_meta_reserve event, the trace event can output garbage:
> qgroup_meta_reserve: 9c7f6acc-b342-4037-bc47-7f6e4d2232d7: refroot=5(FS_TREE) type=DATA diff=2
> qgroup_meta_reserve: 9c7f6acc-b342-4037-bc47-7f6e4d2232d7: refroot=5(FS_TREE) type=0x258792 diff=2
>
> Since we're in qgroup_meta_reserve() trace event, the @type should never
> be DATA, while diff must be aligned to sectorsize (4K in this case).
>
> Only UUID and refroot is correct.
>
> [CAUSE]
> There are two causes for this bug:
>
> - Bad parameter order
> For trace event btrfs:qgroup_meta_reserve, we're passing wrong
> parameters.
>
> The correct parameters are:
> struct btrfs_root, s64 diff, int type.
>
> However the used order is:
> struct btrfs_root, int type, s64 diff.
>
> - @type is not even assigned
> What I was doing !? /facepalm
>
> [FIX]
> Fix the super stupid bug.
>
> Now everything works fine:
> qgroup_meta_reserve: 0477ad60-9aeb-4040-8a03-1900844d46ba: refroot=5(FS_TREE) type=META_PERTRANS diff=81920
> qgroup_meta_reserve: 0477ad60-9aeb-4040-8a03-1900844d46ba: refroot=5(FS_TREE) type=META_PREALLOC diff=16384
> qgroup_meta_reserve: 0477ad60-9aeb-4040-8a03-1900844d46ba: refroot=5(FS_TREE) type=META_PREALLOC diff=0
> qgroup_meta_reserve: 0477ad60-9aeb-4040-8a03-1900844d46ba: refroot=5(FS_TREE) type=META_PREALLOC diff=16384
> qgroup_meta_reserve: 0477ad60-9aeb-4040-8a03-1900844d46ba: refroot=5(FS_TREE) type=META_PREALLOC diff=-16384
> qgroup_meta_reserve: 0477ad60-9aeb-4040-8a03-1900844d46ba: refroot=5(FS_TREE) type=META_PREALLOC diff=16384
> qgroup_meta_reserve: 0477ad60-9aeb-4040-8a03-1900844d46ba: refroot=5(FS_TREE) type=META_PREALLOC diff=-16384
> qgroup_meta_reserve: 0477ad60-9aeb-4040-8a03-1900844d46ba: refroot=5(FS_TREE) type=META_PREALLOC diff=16384
> qgroup_meta_reserve: 0477ad60-9aeb-4040-8a03-1900844d46ba: refroot=5(FS_TREE) type=META_PREALLOC diff=-16384
>
> Fixes: 4ee0d8832c2e ("btrfs: qgroup: Update trace events for metadata reservation")
> Signed-off-by: Qu Wenruo <wqu@suse.com>
> ---
> Changelog:
> v2:
> - Use more accurate comment about the fintuning options
> - Use more elegant method to output uuid
> ---
> fs/btrfs/qgroup.c | 4 ++--
> include/trace/events/btrfs.h | 1 +
> 2 files changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c
> index c4bb69941c77..3ad151655eb8 100644
> --- a/fs/btrfs/qgroup.c
> +++ b/fs/btrfs/qgroup.c
> @@ -3629,7 +3629,7 @@ int __btrfs_qgroup_reserve_meta(struct btrfs_root *root, int num_bytes,
> return 0;
>
> BUG_ON(num_bytes != round_down(num_bytes, fs_info->nodesize));
> - trace_qgroup_meta_reserve(root, type, (s64)num_bytes);
> + trace_qgroup_meta_reserve(root, (s64)num_bytes, type);
> ret = qgroup_reserve(root, num_bytes, enforce, type);
> if (ret < 0)
> return ret;
> @@ -3676,7 +3676,7 @@ void __btrfs_qgroup_free_meta(struct btrfs_root *root, int num_bytes,
> */
> num_bytes = sub_root_meta_rsv(root, num_bytes, type);
> BUG_ON(num_bytes != round_down(num_bytes, fs_info->nodesize));
> - trace_qgroup_meta_reserve(root, type, -(s64)num_bytes);
> + trace_qgroup_meta_reserve(root, -(s64)num_bytes, type);
> btrfs_qgroup_free_refroot(fs_info, root->root_key.objectid,
> num_bytes, type);
> }
> diff --git a/include/trace/events/btrfs.h b/include/trace/events/btrfs.h
> index 5df604de4f11..0ebcaa153f93 100644
> --- a/include/trace/events/btrfs.h
> +++ b/include/trace/events/btrfs.h
> @@ -1710,6 +1710,7 @@ TRACE_EVENT(qgroup_meta_reserve,
> TP_fast_assign_btrfs(root->fs_info,
> __entry->refroot = root->root_key.objectid;
> __entry->diff = diff;
> + __entry->type = type;
> ),
>
> TP_printk_btrfs("refroot=%llu(%s) type=%s diff=%lld",
>
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