| Message ID | 20240408145454.718047-8-hch@lst.de (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | [1/8] xfs: fix error returns from xfs_bmapi_write | expand |
On Mon, Apr 08, 2024 at 04:54:53PM +0200, Christoph Hellwig wrote: > xfs_bmap_add_extent_delay_real takes parts or all of a delalloc extent > and converts them to a real extent. It is written to deal with any > potential overlap of the to be converted range with the delalloc extent, > but it turns out that currently only converting the entire extents, or a > part starting at the beginning is actually exercised, as the only caller > always tries to convert the entire delalloc extent, and either succeeds > or at least progresses partially from the start. > > If it only converts a tiny part of a delalloc extent, the indirect block > calculation for the new delalloc extent (da_new) might be equivalent to that > of the existing delalloc extent (da_new). If this extent conversion now da_old? The code changes make sense to me otherwise. --D > requires allocating an indirect block that gets accounted into da_new, > leading to the assert that da_new must be smaller or equal to da_new > unless we split the extent to trigger. > > Except for the assert that case is actually handled by just trying to > allocate more space, as that already handled for the split case (which > currently can't be reached at all), so just reusing it should be fine. > Except that without dipping into the reserved block pool that would make > it a bit too easy to trigger a fs shutdown due to ENOSPC. So in addition > to adjusting the assert, also dip into the reserved block pool. > > Note that I could only reproduce the assert with a change to only convert > the actually asked range instead of the full delalloc extent from > xfs_bmapi_write. > > Signed-off-by: Christoph Hellwig <hch@lst.de> > --- > fs/xfs/libxfs/xfs_bmap.c | 13 +++++++++---- > 1 file changed, 9 insertions(+), 4 deletions(-) > > diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c > index 08e13ebdee1b53..7700a48e013d5a 100644 > --- a/fs/xfs/libxfs/xfs_bmap.c > +++ b/fs/xfs/libxfs/xfs_bmap.c > @@ -1586,6 +1586,7 @@ xfs_bmap_add_extent_delay_real( > if (error) > goto done; > } > + ASSERT(da_new <= da_old); > break; > > case BMAP_LEFT_FILLING | BMAP_RIGHT_FILLING | BMAP_LEFT_CONTIG: > @@ -1616,6 +1617,7 @@ xfs_bmap_add_extent_delay_real( > if (error) > goto done; > } > + ASSERT(da_new <= da_old); > break; > > case BMAP_LEFT_FILLING | BMAP_RIGHT_FILLING | BMAP_RIGHT_CONTIG: > @@ -1650,6 +1652,7 @@ xfs_bmap_add_extent_delay_real( > if (error) > goto done; > } > + ASSERT(da_new <= da_old); > break; > > case BMAP_LEFT_FILLING | BMAP_RIGHT_FILLING: > @@ -1684,6 +1687,7 @@ xfs_bmap_add_extent_delay_real( > goto done; > } > } > + ASSERT(da_new <= da_old); > break; > > case BMAP_LEFT_FILLING | BMAP_LEFT_CONTIG: > @@ -1722,6 +1726,7 @@ xfs_bmap_add_extent_delay_real( > if (error) > goto done; > } > + ASSERT(da_new <= da_old); > break; > > case BMAP_LEFT_FILLING: > @@ -1812,6 +1817,7 @@ xfs_bmap_add_extent_delay_real( > xfs_iext_update_extent(bma->ip, state, &bma->icur, &PREV); > xfs_iext_next(ifp, &bma->icur); > xfs_iext_update_extent(bma->ip, state, &bma->icur, &RIGHT); > + ASSERT(da_new <= da_old); > break; > > case BMAP_RIGHT_FILLING: > @@ -1861,6 +1867,7 @@ xfs_bmap_add_extent_delay_real( > PREV.br_blockcount = temp; > xfs_iext_insert(bma->ip, &bma->icur, &PREV, state); > xfs_iext_next(ifp, &bma->icur); > + ASSERT(da_new <= da_old); > break; > > case 0: > @@ -1983,11 +1990,9 @@ xfs_bmap_add_extent_delay_real( > } > > /* adjust for changes in reserved delayed indirect blocks */ > - if (da_new != da_old) { > - ASSERT(state == 0 || da_new < da_old); > + if (da_new != da_old) > error = xfs_mod_fdblocks(mp, (int64_t)(da_old - da_new), > - false); > - } > + da_new > da_old); > > xfs_bmap_check_leaf_extents(bma->cur, bma->ip, whichfork); > done: > -- > 2.39.2 > >
On Tue, Apr 09, 2024 at 04:16:45PM -0700, Darrick J. Wong wrote: > On Mon, Apr 08, 2024 at 04:54:53PM +0200, Christoph Hellwig wrote: > > xfs_bmap_add_extent_delay_real takes parts or all of a delalloc extent > > and converts them to a real extent. It is written to deal with any > > potential overlap of the to be converted range with the delalloc extent, > > but it turns out that currently only converting the entire extents, or a > > part starting at the beginning is actually exercised, as the only caller > > always tries to convert the entire delalloc extent, and either succeeds > > or at least progresses partially from the start. > > > > If it only converts a tiny part of a delalloc extent, the indirect block > > calculation for the new delalloc extent (da_new) might be equivalent to that > > of the existing delalloc extent (da_new). If this extent conversion now > > da_old? Yes.
diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c index 08e13ebdee1b53..7700a48e013d5a 100644 --- a/fs/xfs/libxfs/xfs_bmap.c +++ b/fs/xfs/libxfs/xfs_bmap.c @@ -1586,6 +1586,7 @@ xfs_bmap_add_extent_delay_real( if (error) goto done; } + ASSERT(da_new <= da_old); break; case BMAP_LEFT_FILLING | BMAP_RIGHT_FILLING | BMAP_LEFT_CONTIG: @@ -1616,6 +1617,7 @@ xfs_bmap_add_extent_delay_real( if (error) goto done; } + ASSERT(da_new <= da_old); break; case BMAP_LEFT_FILLING | BMAP_RIGHT_FILLING | BMAP_RIGHT_CONTIG: @@ -1650,6 +1652,7 @@ xfs_bmap_add_extent_delay_real( if (error) goto done; } + ASSERT(da_new <= da_old); break; case BMAP_LEFT_FILLING | BMAP_RIGHT_FILLING: @@ -1684,6 +1687,7 @@ xfs_bmap_add_extent_delay_real( goto done; } } + ASSERT(da_new <= da_old); break; case BMAP_LEFT_FILLING | BMAP_LEFT_CONTIG: @@ -1722,6 +1726,7 @@ xfs_bmap_add_extent_delay_real( if (error) goto done; } + ASSERT(da_new <= da_old); break; case BMAP_LEFT_FILLING: @@ -1812,6 +1817,7 @@ xfs_bmap_add_extent_delay_real( xfs_iext_update_extent(bma->ip, state, &bma->icur, &PREV); xfs_iext_next(ifp, &bma->icur); xfs_iext_update_extent(bma->ip, state, &bma->icur, &RIGHT); + ASSERT(da_new <= da_old); break; case BMAP_RIGHT_FILLING: @@ -1861,6 +1867,7 @@ xfs_bmap_add_extent_delay_real( PREV.br_blockcount = temp; xfs_iext_insert(bma->ip, &bma->icur, &PREV, state); xfs_iext_next(ifp, &bma->icur); + ASSERT(da_new <= da_old); break; case 0: @@ -1983,11 +1990,9 @@ xfs_bmap_add_extent_delay_real( } /* adjust for changes in reserved delayed indirect blocks */ - if (da_new != da_old) { - ASSERT(state == 0 || da_new < da_old); + if (da_new != da_old) error = xfs_mod_fdblocks(mp, (int64_t)(da_old - da_new), - false); - } + da_new > da_old); xfs_bmap_check_leaf_extents(bma->cur, bma->ip, whichfork); done:
xfs_bmap_add_extent_delay_real takes parts or all of a delalloc extent and converts them to a real extent. It is written to deal with any potential overlap of the to be converted range with the delalloc extent, but it turns out that currently only converting the entire extents, or a part starting at the beginning is actually exercised, as the only caller always tries to convert the entire delalloc extent, and either succeeds or at least progresses partially from the start. If it only converts a tiny part of a delalloc extent, the indirect block calculation for the new delalloc extent (da_new) might be equivalent to that of the existing delalloc extent (da_new). If this extent conversion now requires allocating an indirect block that gets accounted into da_new, leading to the assert that da_new must be smaller or equal to da_new unless we split the extent to trigger. Except for the assert that case is actually handled by just trying to allocate more space, as that already handled for the split case (which currently can't be reached at all), so just reusing it should be fine. Except that without dipping into the reserved block pool that would make it a bit too easy to trigger a fs shutdown due to ENOSPC. So in addition to adjusting the assert, also dip into the reserved block pool. Note that I could only reproduce the assert with a change to only convert the actually asked range instead of the full delalloc extent from xfs_bmapi_write. Signed-off-by: Christoph Hellwig <hch@lst.de> --- fs/xfs/libxfs/xfs_bmap.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-)