Messages in this thread | | | Date | Tue, 24 Jun 2008 14:34:39 -0700 | From | Joel Becker <> | Subject | Re: configfs: Q: item leak in a failing configfs_attach_group()? |
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On Tue, Jun 24, 2008 at 08:04:56PM +0200, Louis Rilling wrote: > On Tue, Jun 24, 2008 at 10:10:51AM -0700, Joel Becker wrote: > > On Tue, Jun 24, 2008 at 04:16:49PM +0200, Louis Rilling wrote: > > > Hi, > > > > > > I'd like an opinion on the following scenario: > > > > > > process 1: process 2: > > > configfs_mkdir("A") > > > attach_group("A") > > > attach_item("A") > > > d_instantiate("A") > > > populate_groups("A") > > > mutex_lock("A") > > > attach_group("A/B") > > > attach_item("A") > > > d_instantiate("A/B") > > > mkdir("A/B/C") > > > do_path_lookup("A/B/C", LOOKUP_PARENT) > > > > This has to sleep until > > configfs_mkdir("A") finishes. > > It's waiting on A->d_parent's > > i_mutex, which is held by > > sys_mkdirat(). > > Can you be more precise? I don't see where do_path_lookup() locks an inode
It doesn't. It's in lookup_create(), which takes the mutex on the parent of 'A'. Note that the end of sys_mkdirat() explicitly drops that mutex - it couldn't do so if it hadn't been taken :-)
Joel
--
"You cannot bring about prosperity by discouraging thrift. You cannot strengthen the weak by weakening the strong. You cannot help the wage earner by pulling down the wage payer. You cannot further the brotherhood of man by encouraging class hatred. You cannot help the poor by destroying the rich. You cannot build character and courage by taking away a man's initiative and independence. You cannot help men permanently by doing for them what they could and should do for themselves." - Abraham Lincoln
Joel Becker Principal Software Developer Oracle E-mail: joel.becker@oracle.com Phone: (650) 506-8127
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