| Message ID | 152960587035.26246.9220199251468325711.stgit@magnolia (mailing list archive) |
|---|---|
| State | Accepted |
| Headers | show |
Looks fine Reviewed-by: Allison Henderson <allison.henderson@oracle.com> On 06/21/2018 11:31 AM, Darrick J. Wong wrote: > From: Darrick J. Wong <darrick.wong@oracle.com> > > In commit e89c041338ed6ef ("xfs: implement the GETFSMAP ioctl") we > created the ability to obtain empty transactions. These transactions > have no log or block reservations and therefore can't modify anything. > Since they're also NO_WRITECOUNT they can run while the fs is frozen, > so we don't need to WARN_ON about that usage. > > Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> > --- > fs/xfs/xfs_trans.c | 7 ++++++- > 1 file changed, 6 insertions(+), 1 deletion(-) > > > diff --git a/fs/xfs/xfs_trans.c b/fs/xfs/xfs_trans.c > index e040af120b69..524f543c5b82 100644 > --- a/fs/xfs/xfs_trans.c > +++ b/fs/xfs/xfs_trans.c > @@ -258,7 +258,12 @@ xfs_trans_alloc( > if (!(flags & XFS_TRANS_NO_WRITECOUNT)) > sb_start_intwrite(mp->m_super); > > - WARN_ON(mp->m_super->s_writers.frozen == SB_FREEZE_COMPLETE); > + /* > + * Zero-reservation ("empty") transactions can't modify anything, so > + * they're allowed to run while we're frozen. > + */ > + WARN_ON(resp->tr_logres > 0 && > + mp->m_super->s_writers.frozen == SB_FREEZE_COMPLETE); > atomic_inc(&mp->m_active_trans); > > tp = kmem_zone_zalloc(xfs_trans_zone, > > -- > To unsubscribe from this list: send the line "unsubscribe linux-xfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at https://urldefense.proofpoint.com/v2/url?u=http-3A__vger.kernel.org_majordomo-2Dinfo.html&d=DwICaQ&c=RoP1YumCXCgaWHvlZYR8PZh8Bv7qIrMUB65eapI_JnE&r=LHZQ8fHvy6wDKXGTWcm97burZH5sQKHRDMaY1UthQxc&m=jfRT1oYtPVNVBt-lMSR8ZrPgEPjfv7foQ0meuw0oGxM&s=GsacuLUdUkUoZWMAAmlRTyyR7FByN9OA43H6dYDIK6Q&e= > -- To unsubscribe from this list: send the line "unsubscribe linux-xfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Thu, Jun 21, 2018 at 11:31:10AM -0700, Darrick J. Wong wrote: > From: Darrick J. Wong <darrick.wong@oracle.com> > > In commit e89c041338ed6ef ("xfs: implement the GETFSMAP ioctl") we > created the ability to obtain empty transactions. That was sneaked in nicely, normally it should be a separate commit.. > These transactions > have no log or block reservations and therefore can't modify anything. > Since they're also NO_WRITECOUNT they can run while the fs is frozen, > so we don't need to WARN_ON about that usage. This looks correct, but it really makes me hate these empty transactions. We're going to find more and more issues like this and will end up with a huge bag of special cases. Reluctantly: Reviewed-by: Christoph Hellwig <hch@lst.de> -- To unsubscribe from this list: send the line "unsubscribe linux-xfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/fs/xfs/xfs_trans.c b/fs/xfs/xfs_trans.c index e040af120b69..524f543c5b82 100644 --- a/fs/xfs/xfs_trans.c +++ b/fs/xfs/xfs_trans.c @@ -258,7 +258,12 @@ xfs_trans_alloc( if (!(flags & XFS_TRANS_NO_WRITECOUNT)) sb_start_intwrite(mp->m_super); - WARN_ON(mp->m_super->s_writers.frozen == SB_FREEZE_COMPLETE); + /* + * Zero-reservation ("empty") transactions can't modify anything, so + * they're allowed to run while we're frozen. + */ + WARN_ON(resp->tr_logres > 0 && + mp->m_super->s_writers.frozen == SB_FREEZE_COMPLETE); atomic_inc(&mp->m_active_trans); tp = kmem_zone_zalloc(xfs_trans_zone,