diff mbox

[6/7] btrfs: Don't BUG_ON alloc_path errors in find_next_chunk

Message ID 1310681702-13922-7-git-send-email-mfasheh@suse.com (mailing list archive)
State New, archived
Headers show

Commit Message

Mark Fasheh July 14, 2011, 10:15 p.m. UTC
I also removed the BUG_ON from error return of find_next_chunk in
init_first_rw_device(). It turns out that the only caller of
init_first_rw_device() also BUGS on any nonzero return so no actual behavior
change has occurred here.

Signed-off-by: Mark Fasheh <mfasheh@suse.com>
---
 fs/btrfs/volumes.c |    6 ++++--
 1 files changed, 4 insertions(+), 2 deletions(-)

Comments

Tsutomu Itoh July 15, 2011, 2:43 a.m. UTC | #1
(2011/07/15 7:15), Mark Fasheh wrote:
> I also removed the BUG_ON from error return of find_next_chunk in
> init_first_rw_device(). It turns out that the only caller of
> init_first_rw_device() also BUGS on any nonzero return so no actual behavior
> change has occurred here.
> 
> Signed-off-by: Mark Fasheh <mfasheh@suse.com>
> ---
>  fs/btrfs/volumes.c |    6 ++++--
>  1 files changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
> index 530a2fc..90d956c 100644
> --- a/fs/btrfs/volumes.c
> +++ b/fs/btrfs/volumes.c
> @@ -1037,7 +1037,8 @@ static noinline int find_next_chunk(struct btrfs_root *root,
>  	struct btrfs_key found_key;
>  
>  	path = btrfs_alloc_path();
> -	BUG_ON(!path);
> +	if (!path)
> +		return -ENOMEM;

If find_next_chunk() returns -ENOMEM, space_info->full becomes 1 by following code.

3205 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
3206                           struct btrfs_root *extent_root, u64 alloc_bytes,
3207                           u64 flags, int force)
3208 {
...
3277         ret = btrfs_alloc_chunk(trans, extent_root, flags);
3278         spin_lock(&space_info->lock);
3279         if (ret)
3280                 space_info->full = 1;
3281         else
3282                 ret = 1;

Is it OK?

Thanks,
Tsutomu

>  
>  	key.objectid = objectid;
>  	key.offset = (u64)-1;
> @@ -2663,7 +2664,8 @@ static noinline int init_first_rw_device(struct btrfs_trans_handle *trans,
>  
>  	ret = find_next_chunk(fs_info->chunk_root,
>  			      BTRFS_FIRST_CHUNK_TREE_OBJECTID, &chunk_offset);
> -	BUG_ON(ret);
> +	if (ret)
> +		return ret;
>  
>  	alloc_profile = BTRFS_BLOCK_GROUP_METADATA |
>  			(fs_info->metadata_alloc_profile &


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Mark Fasheh July 18, 2011, 9:36 p.m. UTC | #2
Hi Tsutomu,

	Thanks for the review, it is appreciated!

On Fri, Jul 15, 2011 at 11:43:52AM +0900, Tsutomu Itoh wrote:
> > @@ -1037,7 +1037,8 @@ static noinline int find_next_chunk(struct btrfs_root *root,
> >  	struct btrfs_key found_key;
> >  
> >  	path = btrfs_alloc_path();
> > -	BUG_ON(!path);
> > +	if (!path)
> > +		return -ENOMEM;
> 
> If find_next_chunk() returns -ENOMEM, space_info->full becomes 1 by following code.
> 
> 3205 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
> 3206                           struct btrfs_root *extent_root, u64 alloc_bytes,
> 3207                           u64 flags, int force)
> 3208 {
> ...
> 3277         ret = btrfs_alloc_chunk(trans, extent_root, flags);
> 3278         spin_lock(&space_info->lock);
> 3279         if (ret)
> 3280                 space_info->full = 1;
> 3281         else
> 3282                 ret = 1;
> 
> Is it OK?

I don't think so actually. It looks like in this case we might want to
bubble the error back up past do_chunk_alloc and leave space_info untouched.
Chris, does that seem reasonable?
	--Mark

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Chris Mason July 18, 2011, 11:12 p.m. UTC | #3
Excerpts from Mark Fasheh's message of 2011-07-18 17:36:57 -0400:
> Hi Tsutomu,
> 
>     Thanks for the review, it is appreciated!
> 
> On Fri, Jul 15, 2011 at 11:43:52AM +0900, Tsutomu Itoh wrote:
> > > @@ -1037,7 +1037,8 @@ static noinline int find_next_chunk(struct btrfs_root *root,
> > >      struct btrfs_key found_key;
> > >  
> > >      path = btrfs_alloc_path();
> > > -    BUG_ON(!path);
> > > +    if (!path)
> > > +        return -ENOMEM;
> > 
> > If find_next_chunk() returns -ENOMEM, space_info->full becomes 1 by following code.
> > 
> > 3205 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
> > 3206                           struct btrfs_root *extent_root, u64 alloc_bytes,
> > 3207                           u64 flags, int force)
> > 3208 {
> > ...
> > 3277         ret = btrfs_alloc_chunk(trans, extent_root, flags);
> > 3278         spin_lock(&space_info->lock);
> > 3279         if (ret)
> > 3280                 space_info->full = 1;
> > 3281         else
> > 3282                 ret = 1;
> > 
> > Is it OK?
> 
> I don't think so actually. It looks like in this case we might want to
> bubble the error back up past do_chunk_alloc and leave space_info untouched.
> Chris, does that seem reasonable?

Yeah, once space_info->full is 1, we don't flip it back to zero until
more space is available somehow.  We should bubble the error up.

-chris
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diff mbox

Patch

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 530a2fc..90d956c 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -1037,7 +1037,8 @@  static noinline int find_next_chunk(struct btrfs_root *root,
 	struct btrfs_key found_key;
 
 	path = btrfs_alloc_path();
-	BUG_ON(!path);
+	if (!path)
+		return -ENOMEM;
 
 	key.objectid = objectid;
 	key.offset = (u64)-1;
@@ -2663,7 +2664,8 @@  static noinline int init_first_rw_device(struct btrfs_trans_handle *trans,
 
 	ret = find_next_chunk(fs_info->chunk_root,
 			      BTRFS_FIRST_CHUNK_TREE_OBJECTID, &chunk_offset);
-	BUG_ON(ret);
+	if (ret)
+		return ret;
 
 	alloc_profile = BTRFS_BLOCK_GROUP_METADATA |
 			(fs_info->metadata_alloc_profile &