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 introduce 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/libxfs/xfs_ag.c | 88 ++++++++++++++++++++++++++++++++++++++++++
fs/xfs/libxfs/xfs_ag.h | 2 +
fs/xfs/xfs_fsops.c | 77 ++++++++++++++++++++++++++----------
fs/xfs/xfs_trans.c | 1 -
4 files changed, 146 insertions(+), 22 deletions(-)
diff --git a/fs/xfs/libxfs/xfs_ag.c b/fs/xfs/libxfs/xfs_ag.c
index 9331f3516afa..04a7c9b20470 100644
--- a/fs/xfs/libxfs/xfs_ag.c
+++ b/fs/xfs/libxfs/xfs_ag.c
@@ -22,6 +22,8 @@
#include "xfs_ag.h"
#include "xfs_ag_resv.h"
#include "xfs_health.h"
+#include "xfs_error.h"
+#include "xfs_bmap.h"
static int
xfs_get_aghdr_buf(
@@ -485,6 +487,92 @@ xfs_ag_init_headers(
return error;
}
+int
+xfs_ag_shrink_space(
+ struct xfs_mount *mp,
+ struct xfs_trans *tp,
+ struct aghdr_init_data *id,
+ xfs_extlen_t len)
+{
+ struct xfs_alloc_arg args = {
+ .tp = tp,
+ .mp = mp,
+ .type = XFS_ALLOCTYPE_THIS_BNO,
+ .minlen = len,
+ .maxlen = len,
+ .oinfo = XFS_RMAP_OINFO_SKIP_UPDATE,
+ .resv = XFS_AG_RESV_NONE,
+ .prod = 1
+ };
+ struct xfs_buf *agibp, *agfbp;
+ struct xfs_agi *agi;
+ struct xfs_agf *agf;
+ int error, err2;
+
+ ASSERT(id->agno == mp->m_sb.sb_agcount - 1);
+ error = xfs_ialloc_read_agi(mp, tp, id->agno, &agibp);
+ if (error)
+ return error;
+
+ agi = agibp->b_addr;
+
+ error = xfs_alloc_read_agf(mp, tp, id->agno, 0, &agfbp);
+ if (error)
+ return error;
+
+ agf = agfbp->b_addr;
+ if (XFS_IS_CORRUPT(mp, agf->agf_length != agi->agi_length))
+ return -EFSCORRUPTED;
+
+ args.fsbno = XFS_AGB_TO_FSB(mp, id->agno,
+ be32_to_cpu(agi->agi_length) - len);
+
+ /* remove the preallocations before allocation and re-establish then */
+ error = xfs_ag_resv_free(agibp->b_pag);
+ if (error)
+ return error;
+
+ /* internal log shouldn't also show up in the free space btrees */
+ error = xfs_alloc_vextent(&args);
+ if (!error && args.agbno == NULLAGBLOCK)
+ error = -ENOSPC;
+
+ if (error) {
+ err2 = xfs_ag_resv_init(agibp->b_pag, tp);
+ if (err2)
+ goto resv_err;
+ return error;
+ }
+
+ /*
+ * if successfully deleted from freespace btrees, need to confirm
+ * per-AG reservation works as expected.
+ */
+ be32_add_cpu(&agi->agi_length, -len);
+ be32_add_cpu(&agf->agf_length, -len);
+
+ err2 = xfs_ag_resv_init(agibp->b_pag, tp);
+ if (err2) {
+ be32_add_cpu(&agi->agi_length, len);
+ be32_add_cpu(&agf->agf_length, len);
+ if (err2 != -ENOSPC)
+ goto resv_err;
+
+ __xfs_bmap_add_free(tp, args.fsbno, len,
+ &XFS_RMAP_OINFO_SKIP_UPDATE, true);
+ return err2;
+ }
+ xfs_ialloc_log_agi(tp, agibp, XFS_AGI_LENGTH);
+ xfs_alloc_log_agf(tp, agfbp, XFS_AGF_LENGTH);
+ return 0;
+
+resv_err:
+ xfs_warn(mp,
+"Error %d reserving per-AG metadata reserve pool.", err2);
+ xfs_force_shutdown(mp, SHUTDOWN_CORRUPT_INCORE);
+ return err2;
+}
+
/*
* Extent the AG indicated by the @id by the length passed in
*/
diff --git a/fs/xfs/libxfs/xfs_ag.h b/fs/xfs/libxfs/xfs_ag.h
index 5166322807e7..f3b5bbfeadce 100644
--- a/fs/xfs/libxfs/xfs_ag.h
+++ b/fs/xfs/libxfs/xfs_ag.h
@@ -24,6 +24,8 @@ struct aghdr_init_data {
};
int xfs_ag_init_headers(struct xfs_mount *mp, struct aghdr_init_data *id);
+int xfs_ag_shrink_space(struct xfs_mount *mp, struct xfs_trans *tp,
+ struct aghdr_init_data *id, xfs_extlen_t len);
int xfs_ag_extend_space(struct xfs_mount *mp, struct xfs_trans *tp,
struct aghdr_init_data *id, xfs_extlen_t len);
int xfs_ag_get_geometry(struct xfs_mount *mp, xfs_agnumber_t agno,
diff --git a/fs/xfs/xfs_fsops.c b/fs/xfs/xfs_fsops.c
index db6ed354c465..2ae4f33b42c9 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;
}
@@ -137,11 +157,19 @@ 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 (especially sb_fdblocks) now
+ * so xfs_validate_sb_write() can pass.
+ */
+ if (xfs_sb_version_haslazysbcount(&mp->m_sb))
+ xfs_log_sb(tp);
+
xfs_trans_set_sync(tp);
error = xfs_trans_commit(tp);
if (error)
@@ -157,7 +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 (delta > 0) {
struct xfs_perag *pag;
pag = xfs_perag_get(mp, id.agno);
@@ -178,7 +206,14 @@ xfs_growfs_data_private(
return error;
out_trans_cancel:
- xfs_trans_cancel(tp);
+ /*
+ * AGFL fixup can dirty the transaction, so it needs committing anyway.
+ */
+ if (!extend && ((tp->t_flags & XFS_TRANS_DIRTY) ||
+ !list_empty(&tp->t_dfops)))
+ xfs_trans_commit(tp);
+ else
+ xfs_trans_cancel(tp);
return error;
}
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
