btrfs_recover_relocation() invokes btrfs_join_transaction(), which joins
a btrfs_trans_handle object into transactions and returns a reference of
it with increased refcount to "trans".
When btrfs_recover_relocation() returns, "trans" becomes invalid, so the
refcount should be decreased to keep refcount balanced.
The reference counting issue happens in one exception handling path of
btrfs_recover_relocation(). When read_fs_root() failed, the refcnt
increased by btrfs_join_transaction() is not decreased, causing a refcnt
leak.
Fix this issue by calling btrfs_end_transaction() on this error path
when read_fs_root() failed.
Fixes: 79787eaab461 ("btrfs: replace many BUG_ONs with proper error
handling")
Signed-off-by: Xiyu Yang <[email protected]>
Signed-off-by: Xin Tan <[email protected]>
---
fs/btrfs/relocation.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
index 995d4b8b1cfd..46a451594c7a 100644
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -4606,6 +4606,7 @@ int btrfs_recover_relocation(struct btrfs_root *root)
if (IS_ERR(fs_root)) {
err = PTR_ERR(fs_root);
list_add_tail(&reloc_root->root_list, &reloc_roots);
+ btrfs_end_transaction(trans);
goto out_free;
}
--
2.7.4
On Mon, Apr 20, 2020 at 6:50 AM Xiyu Yang <[email protected]> wrote:
>
> btrfs_recover_relocation() invokes btrfs_join_transaction(), which joins
> a btrfs_trans_handle object into transactions and returns a reference of
> it with increased refcount to "trans".
>
> When btrfs_recover_relocation() returns, "trans" becomes invalid, so the
> refcount should be decreased to keep refcount balanced.
>
> The reference counting issue happens in one exception handling path of
> btrfs_recover_relocation(). When read_fs_root() failed, the refcnt
> increased by btrfs_join_transaction() is not decreased, causing a refcnt
> leak.
>
> Fix this issue by calling btrfs_end_transaction() on this error path
> when read_fs_root() failed.
>
> Fixes: 79787eaab461 ("btrfs: replace many BUG_ONs with proper error
> handling")
> Signed-off-by: Xiyu Yang <[email protected]>
> Signed-off-by: Xin Tan <[email protected]>
Reviewed-by: Filipe Manana <[email protected]>
Looks good, thanks.
> ---
> fs/btrfs/relocation.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
> index 995d4b8b1cfd..46a451594c7a 100644
> --- a/fs/btrfs/relocation.c
> +++ b/fs/btrfs/relocation.c
> @@ -4606,6 +4606,7 @@ int btrfs_recover_relocation(struct btrfs_root *root)
> if (IS_ERR(fs_root)) {
> err = PTR_ERR(fs_root);
> list_add_tail(&reloc_root->root_list, &reloc_roots);
> + btrfs_end_transaction(trans);
> goto out_free;
> }
>
> --
> 2.7.4
>
--
Filipe David Manana,
“Whether you think you can, or you think you can't — you're right.”
On Mon, Apr 20, 2020 at 6:34 PM Filipe Manana <[email protected]> wrote:
>
> On Mon, Apr 20, 2020 at 6:50 AM Xiyu Yang <[email protected]> wrote:
> >
> > btrfs_recover_relocation() invokes btrfs_join_transaction(), which joins
> > a btrfs_trans_handle object into transactions and returns a reference of
> > it with increased refcount to "trans".
> >
> > When btrfs_recover_relocation() returns, "trans" becomes invalid, so the
> > refcount should be decreased to keep refcount balanced.
> >
> > The reference counting issue happens in one exception handling path of
> > btrfs_recover_relocation(). When read_fs_root() failed, the refcnt
> > increased by btrfs_join_transaction() is not decreased, causing a refcnt
> > leak.
> >
> > Fix this issue by calling btrfs_end_transaction() on this error path
> > when read_fs_root() failed.
> >
> > Fixes: 79787eaab461 ("btrfs: replace many BUG_ONs with proper error
> > handling")
> > Signed-off-by: Xiyu Yang <[email protected]>
> > Signed-off-by: Xin Tan <[email protected]>
>
> Reviewed-by: Filipe Manana <[email protected]>
>
> Looks good, thanks.
Btw, the subject could be more clear.
Instead of
"btrfs: Fix refcnt leak in btrfs_recover_relocation"
something like
"btrfs: fix transaction leak in ..."
David can probably fixup that when he picks the patch.
Thanks.
>
> > ---
> > fs/btrfs/relocation.c | 1 +
> > 1 file changed, 1 insertion(+)
> >
> > diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
> > index 995d4b8b1cfd..46a451594c7a 100644
> > --- a/fs/btrfs/relocation.c
> > +++ b/fs/btrfs/relocation.c
> > @@ -4606,6 +4606,7 @@ int btrfs_recover_relocation(struct btrfs_root *root)
> > if (IS_ERR(fs_root)) {
> > err = PTR_ERR(fs_root);
> > list_add_tail(&reloc_root->root_list, &reloc_roots);
> > + btrfs_end_transaction(trans);
> > goto out_free;
> > }
> >
> > --
> > 2.7.4
> >
>
>
> --
> Filipe David Manana,
>
> “Whether you think you can, or you think you can't — you're right.”
--
Filipe David Manana,
“Whether you think you can, or you think you can't — you're right.”
On Mon, Apr 20, 2020 at 06:35:56PM +0100, Filipe Manana wrote:
> On Mon, Apr 20, 2020 at 6:34 PM Filipe Manana <[email protected]> wrote:
> >
> > On Mon, Apr 20, 2020 at 6:50 AM Xiyu Yang <[email protected]> wrote:
> > >
> > > btrfs_recover_relocation() invokes btrfs_join_transaction(), which joins
> > > a btrfs_trans_handle object into transactions and returns a reference of
> > > it with increased refcount to "trans".
> > >
> > > When btrfs_recover_relocation() returns, "trans" becomes invalid, so the
> > > refcount should be decreased to keep refcount balanced.
> > >
> > > The reference counting issue happens in one exception handling path of
> > > btrfs_recover_relocation(). When read_fs_root() failed, the refcnt
> > > increased by btrfs_join_transaction() is not decreased, causing a refcnt
> > > leak.
> > >
> > > Fix this issue by calling btrfs_end_transaction() on this error path
> > > when read_fs_root() failed.
> > >
> > > Fixes: 79787eaab461 ("btrfs: replace many BUG_ONs with proper error
> > > handling")
> > > Signed-off-by: Xiyu Yang <[email protected]>
> > > Signed-off-by: Xin Tan <[email protected]>
> >
> > Reviewed-by: Filipe Manana <[email protected]>
> >
> > Looks good, thanks.
>
> Btw, the subject could be more clear.
> Instead of
>
> "btrfs: Fix refcnt leak in btrfs_recover_relocation"
>
> something like
>
> "btrfs: fix transaction leak in ..."
>
> David can probably fixup that when he picks the patch.
Yes, thanks, simple fixups are fine.