[PATCH 16/21] xfs: factor out a xfs_growfs_rt_alloc_fake_mount helper

Darrick J. Wong
2024-10-11T00:59:51Z

Split the code to set up a fake mount point to calculate new RT
geometry out of xfs_growfs_rt_bmblock so that it can be reused.

Note that this changes the rmblocks calculation method to be based
on the passed in rblocks and extsize and not the explicitly passed
one, but both methods will always lead to the same result. The new
version just does a little bit more math while being more general.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
---
fs/xfs/xfs_rtalloc.c | 52 +++++++++++++++++++++++++++++++++++---------------
1 file changed, 36 insertions(+), 16 deletions(-)

diff --git a/fs/xfs/xfs_rtalloc.c b/fs/xfs/xfs_rtalloc.c
index 66e8a5973230e8..53503b675f9519 100644
--- a/fs/xfs/xfs_rtalloc.c
+++ b/fs/xfs/xfs_rtalloc.c
@@ -734,6 +734,36 @@ xfs_rtginode_ensure(
return xfs_rtginode_create(rtg, type, true);
}

+static struct xfs_mount *
+xfs_growfs_rt_alloc_fake_mount(
+ const struct xfs_mount *mp,
+ xfs_rfsblock_t rblocks,
+ xfs_agblock_t rextsize)
+{
+ struct xfs_mount *nmp;
+
+ nmp = kmemdup(mp, sizeof(*mp), GFP_KERNEL);
+ if (!nmp)
+ return NULL;
+ nmp->m_sb.sb_rextsize = rextsize;
+ xfs_mount_sb_set_rextsize(nmp, &nmp->m_sb);
+ nmp->m_sb.sb_rblocks = rblocks;
+ nmp->m_sb.sb_rextents = xfs_rtb_to_rtx(nmp, nmp->m_sb.sb_rblocks);
+ nmp->m_sb.sb_rbmblocks = xfs_rtbitmap_blockcount(nmp,
+ nmp->m_sb.sb_rextents);
+ nmp->m_sb.sb_rextslog = xfs_compute_rextslog(nmp->m_sb.sb_rextents);
+ nmp->m_rsumlevels = nmp->m_sb.sb_rextslog + 1;
+ nmp->m_rsumblocks = xfs_rtsummary_blockcount(nmp, nmp->m_rsumlevels,
+ nmp->m_sb.sb_rbmblocks);
+
+ if (rblocks > 0)
+ nmp->m_features |= XFS_FEAT_REALTIME;
+
+ /* recompute growfsrt reservation from new rsumsize */
+ xfs_trans_resv_calc(nmp, &nmp->m_resv);
+ return nmp;
+}
+
static int
xfs_growfs_rt_bmblock(
struct xfs_rtgroup *rtg,
@@ -756,25 +786,15 @@ xfs_growfs_rt_bmblock(
xfs_rtbxlen_t freed_rtx;
int error;

-
- nrblocks_step = (bmbno + 1) * NBBY * mp->m_sb.sb_blocksize * rextsize;
-
- nmp = nargs.mp = kmemdup(mp, sizeof(*mp), GFP_KERNEL);
- if (!nmp)
- return -ENOMEM;
-
/*
* Calculate new sb and mount fields for this round.
*/
- nmp->m_sb.sb_rextsize = rextsize;
- xfs_mount_sb_set_rextsize(nmp, &nmp->m_sb);
- nmp->m_sb.sb_rbmblocks = bmbno + 1;
- nmp->m_sb.sb_rblocks = min(nrblocks, nrblocks_step);
- nmp->m_sb.sb_rextents = xfs_rtb_to_rtx(nmp, nmp->m_sb.sb_rblocks);
- nmp->m_sb.sb_rextslog = xfs_compute_rextslog(nmp->m_sb.sb_rextents);
- nmp->m_rsumlevels = nmp->m_sb.sb_rextslog + 1;
- nmp->m_rsumblocks = xfs_rtsummary_blockcount(mp, nmp->m_rsumlevels,
- nmp->m_sb.sb_rbmblocks);
+ nrblocks_step = (bmbno + 1) * NBBY * mp->m_sb.sb_blocksize * rextsize;
+ nmp = nargs.mp = xfs_growfs_rt_alloc_fake_mount(mp,
+ min(nrblocks, nrblocks_step), rextsize);
+ if (!nmp)
+ return -ENOMEM;
+
rtg->rtg_extents = xfs_rtgroup_extents(nmp, rtg_rgno(rtg));

/*