Messages in this thread | | | Date | Thu, 20 Nov 2003 22:10:13 +0530 | From | Dipankar Sarma <> | Subject | Re: [PATCH] sysfs_remove_dir Vs dcache_readdir race fix |
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On Thu, Nov 20, 2003 at 07:17:09AM -0800, Andrew Morton wrote: > Maneesh Soni <maneesh@in.ibm.com> wrote: > > cpu 0 cpu 1 > > dcache_dir_open() > > --> adds the cursor dentry > > > > sysfs_remove_dir() > > --> list_del_init cursor dentry > > > > dcache_readdir() > > --> loops forever on inititalized cursor dentry. > > > > > > Though all these operations happen under parent's i_sem, but it is dropped > > between ->open() and ->readdir() as both are different calls. > > > > I think people will also agree that there is no need for sysfs_remove_dir() > > to modify d_subdirs list. > > Seems to me that the libfs code is fragile. > > What happens if the dentry at filp->f_private_data gets moved to a > different directory after someone did dcache_dir_open()? Does the loop > in dcache_readdir() go infinite again?
I am not sure if it is that bad. AFAICS, private_data points to a dummy dentry marking the current directory read position, that dentry cannot be moved to a different directory.
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