As the first step of shrinking, this attempts to enable shrinking
unused space in the last allocation group by fixing up freespace
btree, agi, agf and adjusting super block and use a helper
xfs_ag_shrink_space() to fixup the last AG.
This can be all done in one transaction for now, so I think no
additional protection is needed.
Signed-off-by: Gao Xiang <hsiangkao@xxxxxxxxxx>
---
fs/xfs/xfs_fsops.c | 64 ++++++++++++++++++++++++++++++----------------
fs/xfs/xfs_trans.c | 1 -
2 files changed, 42 insertions(+), 23 deletions(-)
diff --git a/fs/xfs/xfs_fsops.c b/fs/xfs/xfs_fsops.c
index 6c4ab5e31054..4bcea22f7b3f 100644
--- a/fs/xfs/xfs_fsops.c
+++ b/fs/xfs/xfs_fsops.c
@@ -38,7 +38,7 @@ xfs_resizefs_init_new_ags(
struct aghdr_init_data *id,
xfs_agnumber_t oagcount,
xfs_agnumber_t nagcount,
- xfs_rfsblock_t *delta)
+ int64_t *delta)
{
xfs_rfsblock_t nb = mp->m_sb.sb_dblocks + *delta;
int error;
@@ -76,33 +76,41 @@ xfs_growfs_data_private(
xfs_agnumber_t nagcount;
xfs_agnumber_t nagimax = 0;
xfs_rfsblock_t nb, nb_div, nb_mod;
- xfs_rfsblock_t delta;
+ int64_t delta;
xfs_agnumber_t oagcount;
struct xfs_trans *tp;
+ bool extend;
struct aghdr_init_data id = {};
nb = in->newblocks;
- if (nb < mp->m_sb.sb_dblocks)
- return -EINVAL;
- if ((error = xfs_sb_validate_fsb_count(&mp->m_sb, nb)))
+ if (nb == mp->m_sb.sb_dblocks)
+ return 0;
+
+ error = xfs_sb_validate_fsb_count(&mp->m_sb, nb);
+ if (error)
return error;
- error = xfs_buf_read_uncached(mp->m_ddev_targp,
+
+ if (nb > mp->m_sb.sb_dblocks) {
+ error = xfs_buf_read_uncached(mp->m_ddev_targp,
XFS_FSB_TO_BB(mp, nb) - XFS_FSS_TO_BB(mp, 1),
XFS_FSS_TO_BB(mp, 1), 0, &bp, NULL);
- if (error)
- return error;
- xfs_buf_relse(bp);
+ if (error)
+ return error;
+ xfs_buf_relse(bp);
+ }
nb_div = nb;
nb_mod = do_div(nb_div, mp->m_sb.sb_agblocks);
nagcount = nb_div + (nb_mod != 0);
if (nb_mod && nb_mod < XFS_MIN_AG_BLOCKS) {
nagcount--;
- nb = (xfs_rfsblock_t)nagcount * mp->m_sb.sb_agblocks;
- if (nb < mp->m_sb.sb_dblocks)
+ if (nagcount < 2)
return -EINVAL;
+ nb = (xfs_rfsblock_t)nagcount * mp->m_sb.sb_agblocks;
}
+
delta = nb - mp->m_sb.sb_dblocks;
+ extend = (delta > 0);
oagcount = mp->m_sb.sb_agcount;
/* allocate the new per-ag structures */
@@ -110,22 +118,34 @@ xfs_growfs_data_private(
error = xfs_initialize_perag(mp, nagcount, &nagimax);
if (error)
return error;
+ } else if (nagcount < oagcount) {
+ /* TODO: shrinking the entire AGs hasn't yet completed */
+ return -EINVAL;
}
error = xfs_trans_alloc(mp, &M_RES(mp)->tr_growdata,
- XFS_GROWFS_SPACE_RES(mp), 0, XFS_TRANS_RESERVE, &tp);
+ (extend ? XFS_GROWFS_SPACE_RES(mp) : -delta), 0,
+ XFS_TRANS_RESERVE, &tp);
if (error)
return error;
- error = xfs_resizefs_init_new_ags(mp, &id, oagcount, nagcount, &delta);
- if (error)
- goto out_trans_cancel;
-
+ if (extend) {
+ error = xfs_resizefs_init_new_ags(mp, &id, oagcount,
+ nagcount, &delta);
+ if (error)
+ goto out_trans_cancel;
+ }
xfs_trans_agblocks_delta(tp, id.nfree);
- /* If there are new blocks in the old last AG, extend it. */
+ /* If there are some blocks in the last AG, resize it. */
if (delta) {
- error = xfs_ag_extend_space(mp, tp, &id, delta);
+ if (extend) {
+ error = xfs_ag_extend_space(mp, tp, &id, delta);
+ } else {
+ id.agno = nagcount - 1;
+ error = xfs_ag_shrink_space(mp, &tp, &id, -delta);
+ }
+
if (error)
goto out_trans_cancel;
}
@@ -137,15 +157,15 @@ xfs_growfs_data_private(
*/
if (nagcount > oagcount)
xfs_trans_mod_sb(tp, XFS_TRANS_SB_AGCOUNT, nagcount - oagcount);
- if (nb > mp->m_sb.sb_dblocks)
+ if (nb != mp->m_sb.sb_dblocks)
xfs_trans_mod_sb(tp, XFS_TRANS_SB_DBLOCKS,
nb - mp->m_sb.sb_dblocks);
if (id.nfree)
xfs_trans_mod_sb(tp, XFS_TRANS_SB_FDBLOCKS, id.nfree);
/*
- * update in-core counters now to reflect the real numbers
- * (especially sb_fdblocks)
+ * update in-core counters now to reflect the real numbers (especially
+ * sb_fdblocks). And xfs_validate_sb_write() can pass for shrinkfs.
*/
if (xfs_sb_version_haslazysbcount(&mp->m_sb))
xfs_log_sb(tp);
@@ -165,7 +185,7 @@ xfs_growfs_data_private(
* If we expanded the last AG, free the per-AG reservation
* so we can reinitialize it with the new size.
*/
- if (delta) {
+ if (extend && delta) {
struct xfs_perag *pag;
pag = xfs_perag_get(mp, id.agno);
diff --git a/fs/xfs/xfs_trans.c b/fs/xfs/xfs_trans.c
index e72730f85af1..fd2cbf414b80 100644
--- a/fs/xfs/xfs_trans.c
+++ b/fs/xfs/xfs_trans.c
@@ -419,7 +419,6 @@ xfs_trans_mod_sb(
tp->t_res_frextents_delta += delta;
break;
case XFS_TRANS_SB_DBLOCKS:
- ASSERT(delta > 0);
tp->t_dblocks_delta += delta;
break;
case XFS_TRANS_SB_AGCOUNT:
--
2.27.0
