Thanks Pranay. Please see below- On Mon, Sep 1, 2014 at 10:19 AM, Pranay Srivastava <pranjas@xxxxxxxxx> wrote: > > On 01-Sep-2014 10:18 AM, "Pranay Srivastava" <pranjas@xxxxxxxxx> wrote: >> >> >> On 30-Aug-2014 10:49 AM, "Joshi" <joshiiitr@xxxxxxxxx> wrote: >> > >> > I am trying to obtain file name at block layer level (above IO >> > scheduler). >> > At this level I receive bio structure, within which page pointers are >> > kept. >> > >> > Thereby I do following to obtain the inode and dentry - >> > >> > struct inode *inode_ptr = page->mapping->host; >> > if (inode_ptr != NULL) >> > /* Access dentry i.e. i_dentry in the inode */ >> > >> >> Are you doing this in readpage(s) or writepage(s) callback? If that's the >> case your page would be locked and dentry/inode wouldn't go away. >> >> If you are doing something else then first make sure you do lock_page and >> proceed only if you get that page lock. I am not operating at file-system level. I am operating on the bio that file-system(or any other component above IO scheduler) might have sent. Do you think that page descriptor kept in bio (for write) is going to vanish? I am not accessing the data of the page, just the page->mapping pointer. >> Second you can try dget and dput before you start working with dentry. I will try that. >> > This works usually. But problem is, inode and dentry may get released >> > from inode and dentry cache at any time. >> > While accessing inode/dentry I need to ensure that till the time I am >> > accessing'em these structure remain valid in memory. >> > Is it possible to ensure that? Which structures/locks I need to check >> > for the purpose. >> >> is this your observation from your test case? Can you explain your test >> case a bit. No, normally I obtain file name. But with fsstress, this causes crash. >> > Have you seen d_alias and see if that can help you with filename? I do get filename from dentry. But while I am accessing that, it can be freed by vfs. > >> > >> > Appreciate any help. >> > >> > Thanks! >> > >> > -- >> > Joshi >> > >> > _______________________________________________ >> > Kernelnewbies mailing list >> > Kernelnewbies@xxxxxxxxxxxxxxxxx >> > http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies -- Joshi _______________________________________________ Kernelnewbies mailing list Kernelnewbies@xxxxxxxxxxxxxxxxx http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
