svn commit: r280760 - head/sys/ufs/ffs
Ian Lepore
ian at freebsd.org
Fri Mar 27 15:43:26 UTC 2015
On Fri, 2015-03-27 at 13:55 +0000, Konstantin Belousov wrote:
> Author: kib
> Date: Fri Mar 27 13:55:56 2015
> New Revision: 280760
> URL: https://svnweb.freebsd.org/changeset/base/280760
>
> Log:
> Fix the hand after the immediate reboot when the following command
> sequence is performed on UFS SU+J rootfs:
> cp -Rp /sbin/init /sbin/init.old
> mv -f /sbin/init.old /sbin/init
>
> Hang occurs on the rootfs unmount. There are two issues:
>
> 1. Removed init binary, which is still mapped, creates a reference to
> the removed vnode. The inodeblock for such vnode must have active
> inodedep, which is (eventually) linked through the unlinked list. This
> means that ffs_sync(MNT_SUSPEND) cannot succeed, because number of
> softdep workitems for the mp is always > 0. FFS is suspended during
> unmount, so unmount just hangs.
>
> 2. As noted above, the inodedep is linked eventually. It is not
> linked until the superblock is written. But at the vfs_unmountall()
> time, when the rootfs is unmounted, the call is made to
> ffs_unmount()->ffs_sync() before vflush(), and ffs_sync() only calls
> ffs_sbupdate() after all workitems are flushed. It is masked for
> normal system operations, because syncer works in parallel and
> eventually flushes superblock. Syncer is stopped when rootfs
> unmounted, so ffs_sync() must do sb update on its own.
>
> Correct the issues listed above. For MNT_SUSPEND, count the number of
> linked unlinked inodedeps (this is not a typo) and substract the count
> of such workitems from the total. For the second issue, the
> ffs_sbupdate() is called right after device sync in ffs_sync() loop.
>
> There is third problem, occuring with both SU and SU+J. The
> softdep_waitidle() loop, which waits for softdep_flush() thread to
> clear the worklist, only waits 20ms max. It seems that the 1 tick,
> specified for msleep(9), was a typo.
>
> Add fsync(devvp, MNT_WAIT) call to softdep_waitidle(), which seems to
> significantly help the softdep thread, and change the MNT_LAZY update
> at the reboot time to MNT_WAIT for similar reasons. Note that
> userspace cannot create more work while devvp is flushed, since the
> mount point is always suspended before the call to softdep_waitidle()
> in unmount or remount path.
>
> PR: 195458
> In collaboration with: gjb, pho
> Reviewed by: mckusick
> Sponsored by: The FreeBSD Foundation
> MFC after: 2 weeks
>
> Modified:
> head/sys/ufs/ffs/ffs_softdep.c
> head/sys/ufs/ffs/ffs_vfsops.c
This is causing warning: function declaration isn't a prototype on
platforms that still compile with old gcc. Simple fix, but I thought
you might want to do the commit so you can get an mfc reminder along
with the main commit.
-- Ian
Index: sys/ufs/ffs/ffs_softdep.c
===================================================================
--- sys/ufs/ffs/ffs_softdep.c (revision 280761)
+++ sys/ufs/ffs/ffs_softdep.c (working copy)
@@ -804,6 +804,7 @@ static struct indirdep *indirdep_lookup(struct mou
struct buf *);
static void cancel_indirdep(struct indirdep *, struct buf *,
struct freeblks *);
+static int check_inodedep_free(struct inodedep *);
static void free_indirdep(struct indirdep *);
static void free_diradd(struct diradd *, struct workhead *);
static void merge_diradd(struct inodedep *, struct diradd *);
More information about the svn-src-head
mailing list