6.1-stable review patch. If anyone has any objections, please let me know.
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From: Christoph Hellwig hch@lst.de
[ Upstream commit d69bee6a35d3c5e4873b9e164dd1a9711351a97c ]
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_old). 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 Reviewed-by: "Darrick J. Wong" djwong@kernel.org Signed-off-by: Chandan Babu R chandanbabu@kernel.org Signed-off-by: Leah Rumancik leah.rumancik@gmail.com Acked-by: "Darrick J. Wong" djwong@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/xfs/libxfs/xfs_bmap.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-)
--- a/fs/xfs/libxfs/xfs_bmap.c +++ b/fs/xfs/libxfs/xfs_bmap.c @@ -1530,6 +1530,7 @@ 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: @@ -1559,6 +1560,7 @@ 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: @@ -1592,6 +1594,7 @@ xfs_bmap_add_extent_delay_real( if (error) goto done; } + ASSERT(da_new <= da_old); break;
case BMAP_LEFT_FILLING | BMAP_RIGHT_FILLING: @@ -1624,6 +1627,7 @@ xfs_bmap_add_extent_delay_real( goto done; } } + ASSERT(da_new <= da_old); break;
case BMAP_LEFT_FILLING | BMAP_LEFT_CONTIG: @@ -1661,6 +1665,7 @@ xfs_bmap_add_extent_delay_real( if (error) goto done; } + ASSERT(da_new <= da_old); break;
case BMAP_LEFT_FILLING: @@ -1748,6 +1753,7 @@ 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: @@ -1795,6 +1801,7 @@ 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: @@ -1915,11 +1922,9 @@ 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); - } + true);
xfs_bmap_check_leaf_extents(bma->cur, bma->ip, whichfork); done: