* [patch 1/2] Btrfs: double unlock bug in error handling
@ 2012-04-18 6:59 Dan Carpenter
2012-04-18 10:14 ` David Sterba
2012-04-18 11:29 ` Jan Schmidt
0 siblings, 2 replies; 5+ messages in thread
From: Dan Carpenter @ 2012-04-18 6:59 UTC (permalink / raw)
To: Chris Mason, Jeff Mahoney; +Cc: linux-btrfs, kernel-janitors
The caller expects this function to return with the lock held and
releases it immediately on error.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 2b35f8d..a0bb9dc 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -2301,6 +2301,7 @@ static noinline int run_clustered_refs(struct btrfs_trans_handle *trans,
if (ret) {
printk(KERN_DEBUG "btrfs: run_delayed_extent_op returned %d\n", ret);
+ spin_lock(&delayed_refs->lock);
return ret;
}
@@ -2331,6 +2332,7 @@ static noinline int run_clustered_refs(struct btrfs_trans_handle *trans,
if (ret) {
printk(KERN_DEBUG "btrfs: run_one_delayed_ref returned %d\n", ret);
+ spin_lock(&delayed_refs->lock);
return ret;
}
^ permalink raw reply related [flat|nested] 5+ messages in thread* Re: [patch 1/2] Btrfs: double unlock bug in error handling
2012-04-18 6:59 [patch 1/2] Btrfs: double unlock bug in error handling Dan Carpenter
@ 2012-04-18 10:14 ` David Sterba
2012-04-18 11:29 ` Jan Schmidt
1 sibling, 0 replies; 5+ messages in thread
From: David Sterba @ 2012-04-18 10:14 UTC (permalink / raw)
To: Dan Carpenter; +Cc: Chris Mason, Jeff Mahoney, linux-btrfs, kernel-janitors
On Wed, Apr 18, 2012 at 09:59:03AM +0300, Dan Carpenter wrote:
> The caller expects this function to return with the lock held and
> releases it immediately on error.
>
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.cz>
Good catch, thanks.
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [patch 1/2] Btrfs: double unlock bug in error handling
2012-04-18 6:59 [patch 1/2] Btrfs: double unlock bug in error handling Dan Carpenter
2012-04-18 10:14 ` David Sterba
@ 2012-04-18 11:29 ` Jan Schmidt
2012-04-18 11:58 ` David Sterba
2012-04-18 12:06 ` Dan Carpenter
1 sibling, 2 replies; 5+ messages in thread
From: Jan Schmidt @ 2012-04-18 11:29 UTC (permalink / raw)
To: Dan Carpenter; +Cc: Chris Mason, Jeff Mahoney, linux-btrfs, kernel-janitors
On 18.04.2012 08:59, Dan Carpenter wrote:
> The caller expects this function to return with the lock held and
> releases it immediately on error.
>
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
>
> diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
> index 2b35f8d..a0bb9dc 100644
> --- a/fs/btrfs/extent-tree.c
> +++ b/fs/btrfs/extent-tree.c
> @@ -2301,6 +2301,7 @@ static noinline int run_clustered_refs(struct
btrfs_trans_handle *trans,
>
> if (ret) {
> printk(KERN_DEBUG "btrfs: run_delayed_extent_op returned %d\n",
ret);
> + spin_lock(&delayed_refs->lock);
> return ret;
> }
>
> @@ -2331,6 +2332,7 @@ static noinline int run_clustered_refs(struct
btrfs_trans_handle *trans,
>
> if (ret) {
> printk(KERN_DEBUG "btrfs: run_one_delayed_ref returned %d\n", ret);
> + spin_lock(&delayed_refs->lock);
> return ret;
> }
I think the correct way to fix this is:
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index a844204..9af261a 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -2450,7 +2450,6 @@ again:
ret = run_clustered_refs(trans, root, &cluster);
if (ret < 0) {
- spin_unlock(&delayed_refs->lock);
btrfs_abort_transaction(trans, root, ret);
return ret;
}
-Jan
^ permalink raw reply related [flat|nested] 5+ messages in thread* Re: [patch 1/2] Btrfs: double unlock bug in error handling
2012-04-18 11:29 ` Jan Schmidt
@ 2012-04-18 11:58 ` David Sterba
2012-04-18 12:06 ` Dan Carpenter
1 sibling, 0 replies; 5+ messages in thread
From: David Sterba @ 2012-04-18 11:58 UTC (permalink / raw)
To: Jan Schmidt
Cc: Dan Carpenter, Chris Mason, Jeff Mahoney, linux-btrfs,
kernel-janitors
On Wed, Apr 18, 2012 at 01:29:46PM +0200, Jan Schmidt wrote:
> I think the correct way to fix this is:
>
> diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
> index a844204..9af261a 100644
> --- a/fs/btrfs/extent-tree.c
> +++ b/fs/btrfs/extent-tree.c
> @@ -2450,7 +2450,6 @@ again:
>
> ret = run_clustered_refs(trans, root, &cluster);
> if (ret < 0) {
> - spin_unlock(&delayed_refs->lock);
> btrfs_abort_transaction(trans, root, ret);
> return ret;
> }
That's another way to fix it, but I'd rather see the lock/unlock
balanced within a function, and in this case the extra lock does not
hurt as it's a rare codepath.
david
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [patch 1/2] Btrfs: double unlock bug in error handling
2012-04-18 11:29 ` Jan Schmidt
2012-04-18 11:58 ` David Sterba
@ 2012-04-18 12:06 ` Dan Carpenter
1 sibling, 0 replies; 5+ messages in thread
From: Dan Carpenter @ 2012-04-18 12:06 UTC (permalink / raw)
To: Jan Schmidt; +Cc: Chris Mason, Jeff Mahoney, linux-btrfs, kernel-janitors
On Wed, Apr 18, 2012 at 01:29:46PM +0200, Jan Schmidt wrote:
> On 18.04.2012 08:59, Dan Carpenter wrote:
> I think the correct way to fix this is:
>
Yeah. I considered both ways, but I chose the one which makes the
tools happy. Which is the wrong choice, because taking a pointless
lock is wrong even on the slow path and we should improve the tools.
I'll resend.
regards,
dan carpenter
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2012-04-18 12:06 UTC | newest]
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2012-04-18 6:59 [patch 1/2] Btrfs: double unlock bug in error handling Dan Carpenter
2012-04-18 10:14 ` David Sterba
2012-04-18 11:29 ` Jan Schmidt
2012-04-18 11:58 ` David Sterba
2012-04-18 12:06 ` Dan Carpenter
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