| Message ID | 20180628163636.52564-22-bfoster@redhat.com (mailing list archive) |
|---|---|
| State | Accepted |
| Headers | show |
On Thu, Jun 28, 2018 at 12:36:33PM -0400, Brian Foster wrote: > xfs_swap_extent_rmap() uses a local dfops instance with a > transaction from the caller. Since there is only one caller, pull > the dfops structure into the caller and attach it to the > transaction. This avoids the need to clear ->t_dfops to prevent > invalid stack memory access. > > Signed-off-by: Brian Foster <bfoster@redhat.com> Looks good, 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
On Thu, Jun 28, 2018 at 12:36:33PM -0400, Brian Foster wrote: > xfs_swap_extent_rmap() uses a local dfops instance with a > transaction from the caller. Since there is only one caller, pull > the dfops structure into the caller and attach it to the > transaction. This avoids the need to clear ->t_dfops to prevent > invalid stack memory access. > > Signed-off-by: Brian Foster <bfoster@redhat.com> > --- > fs/xfs/xfs_bmap_util.c | 32 +++++++++++++++++++------------- > 1 file changed, 19 insertions(+), 13 deletions(-) > > diff --git a/fs/xfs/xfs_bmap_util.c b/fs/xfs/xfs_bmap_util.c > index 2c0c9534941c..4fdf013603ab 100644 > --- a/fs/xfs/xfs_bmap_util.c > +++ b/fs/xfs/xfs_bmap_util.c > @@ -1570,6 +1570,8 @@ xfs_swap_extent_rmap( > struct xfs_inode *ip, > struct xfs_inode *tip) > { > + struct xfs_trans *tp = *tpp; > + struct xfs_mount *mp = tp->t_mountp; > struct xfs_bmbt_irec irec; > struct xfs_bmbt_irec uirec; > struct xfs_bmbt_irec tirec; > @@ -1577,7 +1579,6 @@ xfs_swap_extent_rmap( > xfs_fileoff_t end_fsb; > xfs_filblks_t count_fsb; > xfs_fsblock_t firstfsb; > - struct xfs_defer_ops dfops; > int error; > xfs_filblks_t ilen; > xfs_filblks_t rlen; > @@ -1613,7 +1614,7 @@ xfs_swap_extent_rmap( > > /* Unmap the old blocks in the source file. */ > while (tirec.br_blockcount) { > - xfs_defer_init(&dfops, &firstfsb); > + xfs_defer_init(tp->t_dfops, &firstfsb); > trace_xfs_swap_extent_rmap_remap_piece(tip, &tirec); > > /* Read extent from the source file */ > @@ -1635,31 +1636,32 @@ xfs_swap_extent_rmap( > trace_xfs_swap_extent_rmap_remap_piece(tip, &uirec); > > /* Remove the mapping from the donor file. */ > - error = xfs_bmap_unmap_extent((*tpp)->t_mountp, &dfops, > - tip, &uirec); > + error = xfs_bmap_unmap_extent(mp, tp->t_dfops, tip, > + &uirec); > if (error) > goto out_defer; > > /* Remove the mapping from the source file. */ > - error = xfs_bmap_unmap_extent((*tpp)->t_mountp, &dfops, > - ip, &irec); > + error = xfs_bmap_unmap_extent(mp, tp->t_dfops, ip, > + &irec); > if (error) > goto out_defer; > > /* Map the donor file's blocks into the source file. */ > - error = xfs_bmap_map_extent((*tpp)->t_mountp, &dfops, > - ip, &uirec); > + error = xfs_bmap_map_extent(mp, tp->t_dfops, ip, > + &uirec); > if (error) > goto out_defer; > > /* Map the source file's blocks into the donor file. */ > - error = xfs_bmap_map_extent((*tpp)->t_mountp, &dfops, > - tip, &irec); > + error = xfs_bmap_map_extent(mp, tp->t_dfops, tip, > + &irec); > if (error) > goto out_defer; > > - xfs_defer_ijoin(&dfops, ip); > - error = xfs_defer_finish(tpp, &dfops); > + xfs_defer_ijoin(tp->t_dfops, ip); > + error = xfs_defer_finish(tpp, tp->t_dfops); > + tp = *tpp; > if (error) > goto out_defer; > > @@ -1679,7 +1681,7 @@ xfs_swap_extent_rmap( > return 0; > > out_defer: > - xfs_defer_cancel(&dfops); > + xfs_defer_cancel(tp->t_dfops); > out: > trace_xfs_swap_extent_rmap_error(ip, error, _RET_IP_); > tip->i_d.di_flags2 = tip_flags2; > @@ -1846,6 +1848,7 @@ xfs_swap_extents( > { > struct xfs_mount *mp = ip->i_mount; > struct xfs_trans *tp; > + struct xfs_defer_ops dfops; > struct xfs_bstat *sbp = &sxp->sx_stat; > int src_log_flags, target_log_flags; > int error = 0; > @@ -1853,6 +1856,7 @@ xfs_swap_extents( > struct xfs_ifork *cowfp; > uint64_t f; > int resblks = 0; > + xfs_fsblock_t firstfsb; > > /* > * Lock the inodes against other IO, page faults and truncate to > @@ -1915,6 +1919,8 @@ xfs_swap_extents( > error = xfs_trans_alloc(mp, &M_RES(mp)->tr_write, resblks, 0, 0, &tp); > if (error) > goto out_unlock; > + xfs_defer_init(&dfops, &firstfsb); > + tp->t_dfops = &dfops; Hmm... another redundant initialization here, and extra stack usage too. If we're going to move the dfops into struct xfs_trans I don't want this series and that series to be split across a release with all these bits scattered everywhere for a single release. It's at this point I'm tempted to suggest starting this series over with adding a new dfops to the transaction and then converting the t_agfl_dfops and the open-coded/stack-allocated dfops to use the one embedded in the transaction, if nothing else to avoid all this scattered churn. OTOH I also see that you already moved firstblock into the transaction. I'll keep my mouth shut until I get to the end of that series because I sense there's a lot of changes captured in those two series that would happen even if you'd started with putting the dfops in the transaction. Maybe you're really close to mailing out that last piece anyway. Code otherwise looks ok, if a bit messy: Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> --D > > /* > * Lock and join the inodes to the tansaction so that transaction commit > -- > 2.17.1 > > -- > 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 -- 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 Tue, Jul 03, 2018 at 02:22:29PM -0700, Darrick J. Wong wrote: > On Thu, Jun 28, 2018 at 12:36:33PM -0400, Brian Foster wrote: > > xfs_swap_extent_rmap() uses a local dfops instance with a > > transaction from the caller. Since there is only one caller, pull > > the dfops structure into the caller and attach it to the > > transaction. This avoids the need to clear ->t_dfops to prevent > > invalid stack memory access. > > > > Signed-off-by: Brian Foster <bfoster@redhat.com> > > --- > > fs/xfs/xfs_bmap_util.c | 32 +++++++++++++++++++------------- > > 1 file changed, 19 insertions(+), 13 deletions(-) > > > > diff --git a/fs/xfs/xfs_bmap_util.c b/fs/xfs/xfs_bmap_util.c > > index 2c0c9534941c..4fdf013603ab 100644 > > --- a/fs/xfs/xfs_bmap_util.c > > +++ b/fs/xfs/xfs_bmap_util.c > > @@ -1570,6 +1570,8 @@ xfs_swap_extent_rmap( > > struct xfs_inode *ip, > > struct xfs_inode *tip) > > { > > + struct xfs_trans *tp = *tpp; > > + struct xfs_mount *mp = tp->t_mountp; > > struct xfs_bmbt_irec irec; > > struct xfs_bmbt_irec uirec; > > struct xfs_bmbt_irec tirec; > > @@ -1577,7 +1579,6 @@ xfs_swap_extent_rmap( > > xfs_fileoff_t end_fsb; > > xfs_filblks_t count_fsb; > > xfs_fsblock_t firstfsb; > > - struct xfs_defer_ops dfops; > > int error; > > xfs_filblks_t ilen; > > xfs_filblks_t rlen; > > @@ -1613,7 +1614,7 @@ xfs_swap_extent_rmap( > > > > /* Unmap the old blocks in the source file. */ > > while (tirec.br_blockcount) { > > - xfs_defer_init(&dfops, &firstfsb); > > + xfs_defer_init(tp->t_dfops, &firstfsb); > > trace_xfs_swap_extent_rmap_remap_piece(tip, &tirec); > > > > /* Read extent from the source file */ > > @@ -1635,31 +1636,32 @@ xfs_swap_extent_rmap( > > trace_xfs_swap_extent_rmap_remap_piece(tip, &uirec); > > > > /* Remove the mapping from the donor file. */ > > - error = xfs_bmap_unmap_extent((*tpp)->t_mountp, &dfops, > > - tip, &uirec); > > + error = xfs_bmap_unmap_extent(mp, tp->t_dfops, tip, > > + &uirec); > > if (error) > > goto out_defer; > > > > /* Remove the mapping from the source file. */ > > - error = xfs_bmap_unmap_extent((*tpp)->t_mountp, &dfops, > > - ip, &irec); > > + error = xfs_bmap_unmap_extent(mp, tp->t_dfops, ip, > > + &irec); > > if (error) > > goto out_defer; > > > > /* Map the donor file's blocks into the source file. */ > > - error = xfs_bmap_map_extent((*tpp)->t_mountp, &dfops, > > - ip, &uirec); > > + error = xfs_bmap_map_extent(mp, tp->t_dfops, ip, > > + &uirec); > > if (error) > > goto out_defer; > > > > /* Map the source file's blocks into the donor file. */ > > - error = xfs_bmap_map_extent((*tpp)->t_mountp, &dfops, > > - tip, &irec); > > + error = xfs_bmap_map_extent(mp, tp->t_dfops, tip, > > + &irec); > > if (error) > > goto out_defer; > > > > - xfs_defer_ijoin(&dfops, ip); > > - error = xfs_defer_finish(tpp, &dfops); > > + xfs_defer_ijoin(tp->t_dfops, ip); > > + error = xfs_defer_finish(tpp, tp->t_dfops); > > + tp = *tpp; > > if (error) > > goto out_defer; > > > > @@ -1679,7 +1681,7 @@ xfs_swap_extent_rmap( > > return 0; > > > > out_defer: > > - xfs_defer_cancel(&dfops); > > + xfs_defer_cancel(tp->t_dfops); > > out: > > trace_xfs_swap_extent_rmap_error(ip, error, _RET_IP_); > > tip->i_d.di_flags2 = tip_flags2; > > @@ -1846,6 +1848,7 @@ xfs_swap_extents( > > { > > struct xfs_mount *mp = ip->i_mount; > > struct xfs_trans *tp; > > + struct xfs_defer_ops dfops; > > struct xfs_bstat *sbp = &sxp->sx_stat; > > int src_log_flags, target_log_flags; > > int error = 0; > > @@ -1853,6 +1856,7 @@ xfs_swap_extents( > > struct xfs_ifork *cowfp; > > uint64_t f; > > int resblks = 0; > > + xfs_fsblock_t firstfsb; > > > > /* > > * Lock the inodes against other IO, page faults and truncate to > > @@ -1915,6 +1919,8 @@ xfs_swap_extents( > > error = xfs_trans_alloc(mp, &M_RES(mp)->tr_write, resblks, 0, 0, &tp); > > if (error) > > goto out_unlock; > > + xfs_defer_init(&dfops, &firstfsb); > > + tp->t_dfops = &dfops; > > Hmm... another redundant initialization here, and extra stack usage too. > Similar to the last one, the initial init is to facilitate the future change where dfops may be initted by the transaction allocation. Not quite as similar to the last one, this path already does repeated inits because dfops/firstblock is reused in the associated loop. So technically I don't see how this changes much (aside from the dummy firstfsb in the caller, which could just be replaced with 'f' or something if we care that much about it). Since dfops should be empty/initted after a finish anyways, this defer init could probably go away in the firstblock series once the latter is automatically reinitialized on tx roll (though the v1 I posted doesn't remove it). > If we're going to move the dfops into struct xfs_trans I don't want this > series and that series to be split across a release with all these bits > scattered everywhere for a single release. > > It's at this point I'm tempted to suggest starting this series over with > adding a new dfops to the transaction and then converting the > t_agfl_dfops and the open-coded/stack-allocated dfops to use the one > embedded in the transaction, if nothing else to avoid all this scattered > churn. > I think that just changes the order and manner of the churn. Regardless, it's fine with me if we want to hold merging any of it until the whole thing is posted. I may still have posted these bits regardless as review/rfc checkpoints. > OTOH I also see that you already moved firstblock into the transaction. > I'll keep my mouth shut until I get to the end of that series because I > sense there's a lot of changes captured in those two series that would > happen even if you'd started with putting the dfops in the transaction. > Maybe you're really close to mailing out that last piece anyway. > Not really, I'm just starting to look at the last bit. I don't think it will be that difficult once the core bits are worked out, however, so I could just incorporate the current feedback and post the whole thing as one big series rather than worry about v2 of each of the series' posted so far. Doing it incrementally seemed safer and easier to me, but either way is fine with me. Brian > Code otherwise looks ok, if a bit messy: > Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> > > --D > > > > > /* > > * Lock and join the inodes to the tansaction so that transaction commit > > -- > > 2.17.1 > > > > -- > > 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 -- 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_bmap_util.c b/fs/xfs/xfs_bmap_util.c index 2c0c9534941c..4fdf013603ab 100644 --- a/fs/xfs/xfs_bmap_util.c +++ b/fs/xfs/xfs_bmap_util.c @@ -1570,6 +1570,8 @@ xfs_swap_extent_rmap( struct xfs_inode *ip, struct xfs_inode *tip) { + struct xfs_trans *tp = *tpp; + struct xfs_mount *mp = tp->t_mountp; struct xfs_bmbt_irec irec; struct xfs_bmbt_irec uirec; struct xfs_bmbt_irec tirec; @@ -1577,7 +1579,6 @@ xfs_swap_extent_rmap( xfs_fileoff_t end_fsb; xfs_filblks_t count_fsb; xfs_fsblock_t firstfsb; - struct xfs_defer_ops dfops; int error; xfs_filblks_t ilen; xfs_filblks_t rlen; @@ -1613,7 +1614,7 @@ xfs_swap_extent_rmap( /* Unmap the old blocks in the source file. */ while (tirec.br_blockcount) { - xfs_defer_init(&dfops, &firstfsb); + xfs_defer_init(tp->t_dfops, &firstfsb); trace_xfs_swap_extent_rmap_remap_piece(tip, &tirec); /* Read extent from the source file */ @@ -1635,31 +1636,32 @@ xfs_swap_extent_rmap( trace_xfs_swap_extent_rmap_remap_piece(tip, &uirec); /* Remove the mapping from the donor file. */ - error = xfs_bmap_unmap_extent((*tpp)->t_mountp, &dfops, - tip, &uirec); + error = xfs_bmap_unmap_extent(mp, tp->t_dfops, tip, + &uirec); if (error) goto out_defer; /* Remove the mapping from the source file. */ - error = xfs_bmap_unmap_extent((*tpp)->t_mountp, &dfops, - ip, &irec); + error = xfs_bmap_unmap_extent(mp, tp->t_dfops, ip, + &irec); if (error) goto out_defer; /* Map the donor file's blocks into the source file. */ - error = xfs_bmap_map_extent((*tpp)->t_mountp, &dfops, - ip, &uirec); + error = xfs_bmap_map_extent(mp, tp->t_dfops, ip, + &uirec); if (error) goto out_defer; /* Map the source file's blocks into the donor file. */ - error = xfs_bmap_map_extent((*tpp)->t_mountp, &dfops, - tip, &irec); + error = xfs_bmap_map_extent(mp, tp->t_dfops, tip, + &irec); if (error) goto out_defer; - xfs_defer_ijoin(&dfops, ip); - error = xfs_defer_finish(tpp, &dfops); + xfs_defer_ijoin(tp->t_dfops, ip); + error = xfs_defer_finish(tpp, tp->t_dfops); + tp = *tpp; if (error) goto out_defer; @@ -1679,7 +1681,7 @@ xfs_swap_extent_rmap( return 0; out_defer: - xfs_defer_cancel(&dfops); + xfs_defer_cancel(tp->t_dfops); out: trace_xfs_swap_extent_rmap_error(ip, error, _RET_IP_); tip->i_d.di_flags2 = tip_flags2; @@ -1846,6 +1848,7 @@ xfs_swap_extents( { struct xfs_mount *mp = ip->i_mount; struct xfs_trans *tp; + struct xfs_defer_ops dfops; struct xfs_bstat *sbp = &sxp->sx_stat; int src_log_flags, target_log_flags; int error = 0; @@ -1853,6 +1856,7 @@ xfs_swap_extents( struct xfs_ifork *cowfp; uint64_t f; int resblks = 0; + xfs_fsblock_t firstfsb; /* * Lock the inodes against other IO, page faults and truncate to @@ -1915,6 +1919,8 @@ xfs_swap_extents( error = xfs_trans_alloc(mp, &M_RES(mp)->tr_write, resblks, 0, 0, &tp); if (error) goto out_unlock; + xfs_defer_init(&dfops, &firstfsb); + tp->t_dfops = &dfops; /* * Lock and join the inodes to the tansaction so that transaction commit
xfs_swap_extent_rmap() uses a local dfops instance with a transaction from the caller. Since there is only one caller, pull the dfops structure into the caller and attach it to the transaction. This avoids the need to clear ->t_dfops to prevent invalid stack memory access. Signed-off-by: Brian Foster <bfoster@redhat.com> --- fs/xfs/xfs_bmap_util.c | 32 +++++++++++++++++++------------- 1 file changed, 19 insertions(+), 13 deletions(-)