Hi, The below commit that is present in 3.9-rc1 is buggy. It releases the page at which point it may no longer exist and then it unlocks it afterwards. Even if you are somehow getting away with it I think it is an explosion/memory corruption waiting to happen... Best regards, Anton On 2 Mar 2013, at 19:55, Linux Kernel Mailing List <linux-kernel@xxxxxxxxxxxxxxx> wrote: > Gitweb: http://git.kernel.org/linus/;a=commit;h=c51bb0ea40ca038da26b1fa7d450f4078124af03 > Commit: c51bb0ea40ca038da26b1fa7d450f4078124af03 > Parent: 0b7bc84000d71f3647ca33ab1bf5bd928535c846 > Author: Ouyang Maochun <ouyang.maochun@xxxxxxxxxx> > AuthorDate: Mon Feb 18 09:54:52 2013 -0600 > Committer: Steve French <sfrench@xxxxxxxxxx> > CommitDate: Thu Feb 28 09:01:47 2013 -0600 > > cifs: bugfix for unreclaimed writeback pages in cifs_writev_requeue() > > Pages get the PG_writeback flag set before cifs sends its > request to SMB server in cifs_writepages(), if the SMB service > goes down, cifs may try to recommit the writing requests in > cifs_writev_requeue(). However, it does not clean its PG_writeback > flag and relaimed the pages even if it fails again in > cifs_writev_requeue(), which may lead to the hanging of the > processes accessing the cifs directory. This patch just cleans > the PG_writeback flags and reclaims the pages under that circumstances. > > Steps to reproduce the bug(trying serveral times may trigger the issue): > 1.Write from cifs client continuously.(e.g dd if=/dev/zero of=<cifs file>) > 2.Stop SMB service from server.(e.g service smb stop) > 3.Wait for two minutes， and then start SMB service from > server.(e.g service smb start) > 4.The processes which are accessing cifs directory may hang up. > > Signed-off-by: Ouyang Maochun <ouyang.maochun@xxxxxxxxxx> > Signed-off-by: Jiang Yong <jian.yong5@xxxxxxxxxx> > Tested-by: Zhang Xianwei <zhang.xianwei8@xxxxxxxxxx> > Reviewed-by: Wang Liang <wang.liang82@xxxxxxxxxx> > Reviewed-by: Cai Qu <cai.qu@xxxxxxxxxx> > Reviewed-by: Jiang Biao <jiang.biao2@xxxxxxxxxx> > Reviewed-by: Jeff Layton <jlayton@xxxxxxxxxx> > Reviewed-by: Pavel Shilovsky <piastry@xxxxxxxxxxx> > Signed-off-by: Steve French <sfrench@xxxxxxxxxx> > --- > fs/cifs/cifssmb.c | 5 ++++- > 1 files changed, 4 insertions(+), 1 deletions(-) > > diff --git a/fs/cifs/cifssmb.c b/fs/cifs/cifssmb.c > index 00e12f2..7353bc5 100644 > --- a/fs/cifs/cifssmb.c > +++ b/fs/cifs/cifssmb.c > @@ -1909,8 +1909,11 @@ cifs_writev_requeue(struct cifs_writedata *wdata) > } while (rc == -EAGAIN); > > for (i = 0; i < wdata->nr_pages; i++) { > - if (rc != 0) > + if (rc != 0) { > SetPageError(wdata->pages[i]); > + end_page_writeback(wdata->pages[i]); > + page_cache_release(wdata->pages[i]); > + } > unlock_page(wdata->pages[i]); > } > -- Anton Altaparmakov <aia21 at cam.ac.uk> (replace at with @) Unix Support, Computing Service, University of Cambridge, CB2 3QH, UK Linux NTFS maintainer, http://www.linux-ntfs.org/ -- To unsubscribe from this list: send the line "unsubscribe linux-cifs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
