[PATCH 6.6 265/396] xfs: recompute growfsrtfree transaction reservation while growing rt volume

Greg Kroah-Hartman
2024-04-01T16:49:23Z

commit 578bd4ce7100ae34f98c6b0147fe75cfa0dadbac upstream.

While playing with growfs to create a 20TB realtime section on a
filesystem that didn't previously have an rt section, I noticed that
growfs would occasionally shut down the log due to a transaction
reservation overflow.

xfs_calc_growrtfree_reservation uses the current size of the realtime
summary file (m_rsumsize) to compute the transaction reservation for a
growrtfree transaction. The reservations are computed at mount time,
which means that m_rsumsize is zero when growfs starts "freeing" the new
realtime extents into the rt volume. As a result, the transaction is
undersized and fails.

Fix this by recomputing the transaction reservations every time we
change m_rsumsize.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Catherine Hoang <catherine.hoang@oracle.com>
Acked-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
fs/xfs/xfs_rtalloc.c | 5 +++++
1 file changed, 5 insertions(+)

--- a/fs/xfs/xfs_rtalloc.c
+++ b/fs/xfs/xfs_rtalloc.c
@@ -1070,6 +1070,9 @@ xfs_growfs_rt(
nsbp->sb_rbmblocks;
nrsumblocks = XFS_B_TO_FSB(mp, nrsumsize);
nmp->m_rsumsize = nrsumsize = XFS_FSB_TO_B(mp, nrsumblocks);
+ /* recompute growfsrt reservation from new rsumsize */
+ xfs_trans_resv_calc(nmp, &nmp->m_resv);
+
/*
* Start a transaction, get the log reservation.
*/
@@ -1153,6 +1156,8 @@ error_cancel:
*/
mp->m_rsumlevels = nrsumlevels;
mp->m_rsumsize = nrsumsize;
+ /* recompute growfsrt reservation from new rsumsize */
+ xfs_trans_resv_calc(mp, &mp->m_resv);

error = xfs_trans_commit(tp);
if (error)