[PATCH 10/23] xfs: pass perags around in fsmap data dev functions

Dave Chinner
2021-05-19T01:21:10Z

Needs a [from, to] ranged AG walk, and the perag to be stuffed into
the info structure for callouts to use.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
---
fs/xfs/libxfs/xfs_ag.h | 14 ++++++--
fs/xfs/xfs_fsmap.c | 75 ++++++++++++++++++++++++++----------------
2 files changed, 58 insertions(+), 31 deletions(-)

diff --git a/fs/xfs/libxfs/xfs_ag.h b/fs/xfs/libxfs/xfs_ag.h
index 3fa88222dacd..bebbe1bfce27 100644
--- a/fs/xfs/libxfs/xfs_ag.h
+++ b/fs/xfs/libxfs/xfs_ag.h
@@ -116,14 +116,24 @@ void xfs_perag_put(struct xfs_perag *pag);

/*
* Perag iteration APIs
+ *
+ * XXX: for_each_perag_range() usage really needs an iterator to clean up when
+ * we terminate at end_agno because we may have taken a reference to the perag
+ * beyond end_agno. RIght now callers have to be careful to catch and clean that
+ * up themselves. This is not necessary for the callers of for_each_perag() and
+ * for_each_perag_from() because they terminate at sb_agcount where there are
+ * no perag structures in tree beyond end_agno.
*/
-#define for_each_perag_from(mp, next_agno, pag) \
+#define for_each_perag_range(mp, next_agno, end_agno, pag) \
for ((pag) = xfs_perag_get((mp), (next_agno)); \
- (pag) != NULL; \
+ (pag) != NULL && (next_agno) <= (end_agno); \
(next_agno) = (pag)->pag_agno + 1, \
xfs_perag_put(pag), \
(pag) = xfs_perag_get((mp), (next_agno)))

+#define for_each_perag_from(mp, next_agno, pag) \
+ for_each_perag_range((mp), (next_agno), (mp)->m_sb.sb_agcount, (pag))
+
#define for_each_perag(mp, next_agno, pag) \
(next_agno) = 0; \
for_each_perag_from((mp), (next_agno), (pag))
diff --git a/fs/xfs/xfs_fsmap.c b/fs/xfs/xfs_fsmap.c
index 34f2b971ce43..835dd6e3819b 100644
--- a/fs/xfs/xfs_fsmap.c
+++ b/fs/xfs/xfs_fsmap.c
@@ -24,6 +24,7 @@
#include "xfs_refcount_btree.h"
#include "xfs_alloc_btree.h"
#include "xfs_rtalloc.h"
+#include "xfs_ag.h"

/* Convert an xfs_fsmap to an fsmap. */
static void
@@ -157,10 +158,10 @@ struct xfs_getfsmap_info {
struct xfs_fsmap_head *head;
struct fsmap *fsmap_recs; /* mapping records */
struct xfs_buf *agf_bp; /* AGF, for refcount queries */
+ struct xfs_perag *pag; /* AG info, if applicable */
xfs_daddr_t next_daddr; /* next daddr we expect */
u64 missing_owner; /* owner of holes */
u32 dev; /* device id */
- xfs_agnumber_t agno; /* AG number, if applicable */
struct xfs_rmap_irec low; /* low rmap key */
struct xfs_rmap_irec high; /* high rmap key */
bool last; /* last extent? */
@@ -203,14 +204,14 @@ xfs_getfsmap_is_shared(
*stat = false;
if (!xfs_sb_version_hasreflink(&mp->m_sb))
return 0;
- /* rt files will have agno set to NULLAGNUMBER */
- if (info->agno == NULLAGNUMBER)
+ /* rt files will have no perag structure */
+ if (!info->pag)
return 0;

/* Are there any shared blocks here? */
flen = 0;
cur = xfs_refcountbt_init_cursor(mp, tp, info->agf_bp,
- info->agno);
+ info->pag->pag_agno);

error = xfs_refcount_find_shared(cur, rec->rm_startblock,
rec->rm_blockcount, &fbno, &flen, false);
@@ -311,7 +312,8 @@ xfs_getfsmap_helper(
if (info->head->fmh_entries >= info->head->fmh_count)
return -ECANCELED;

- trace_xfs_fsmap_mapping(mp, info->dev, info->agno, rec);
+ trace_xfs_fsmap_mapping(mp, info->dev,
+ info->pag ? info->pag->pag_agno : NULLAGNUMBER, rec);

fmr.fmr_device = info->dev;
fmr.fmr_physical = rec_daddr;
@@ -429,8 +431,8 @@ xfs_getfsmap_logdev(
info->high.rm_flags = XFS_RMAP_KEY_FLAGS | XFS_RMAP_REC_FLAGS;
info->missing_owner = XFS_FMR_OWN_FREE;

- trace_xfs_fsmap_low_key(mp, info->dev, info->agno, &info->low);
- trace_xfs_fsmap_high_key(mp, info->dev, info->agno, &info->high);
+ trace_xfs_fsmap_low_key(mp, info->dev, NULLAGNUMBER, &info->low);
+ trace_xfs_fsmap_high_key(mp, info->dev, NULLAGNUMBER, &info->high);

if (keys[0].fmr_physical > 0)
return 0;
@@ -508,8 +510,8 @@ __xfs_getfsmap_rtdev(
info->high.rm_blockcount = 0;
xfs_getfsmap_set_irec_flags(&info->high, &keys[1]);

- trace_xfs_fsmap_low_key(mp, info->dev, info->agno, &info->low);
- trace_xfs_fsmap_high_key(mp, info->dev, info->agno, &info->high);
+ trace_xfs_fsmap_low_key(mp, info->dev, NULLAGNUMBER, &info->low);
+ trace_xfs_fsmap_high_key(mp, info->dev, NULLAGNUMBER, &info->high);

return query_fn(tp, info);
}
@@ -572,6 +574,7 @@ __xfs_getfsmap_datadev(
void *priv)
{
struct xfs_mount *mp = tp->t_mountp;
+ struct xfs_perag *pag;
struct xfs_btree_cur *bt_cur = NULL;
xfs_fsblock_t start_fsb;
xfs_fsblock_t end_fsb;
@@ -610,20 +613,20 @@ __xfs_getfsmap_datadev(
start_ag = XFS_FSB_TO_AGNO(mp, start_fsb);
end_ag = XFS_FSB_TO_AGNO(mp, end_fsb);

- /* Query each AG */
- for (info->agno = start_ag; info->agno <= end_ag; info->agno++) {
+ for_each_perag_range(mp, start_ag, end_ag, pag) {
/*
* Set the AG high key from the fsmap high key if this
* is the last AG that we're querying.
*/
- if (info->agno == end_ag) {
+ info->pag = pag;
+ if (pag->pag_agno == end_ag) {
info->high.rm_startblock = XFS_FSB_TO_AGBNO(mp,
end_fsb);
info->high.rm_offset = XFS_BB_TO_FSBT(mp,
keys[1].fmr_offset);
error = xfs_fsmap_owner_to_rmap(&info->high, &keys[1]);
if (error)
- goto err;
+ break;
xfs_getfsmap_set_irec_flags(&info->high, &keys[1]);
}

@@ -634,38 +637,45 @@ __xfs_getfsmap_datadev(
info->agf_bp = NULL;
}

- error = xfs_alloc_read_agf(mp, tp, info->agno, 0,
+ error = xfs_alloc_read_agf(mp, tp, pag->pag_agno, 0,
&info->agf_bp);
if (error)
- goto err;
+ break;

- trace_xfs_fsmap_low_key(mp, info->dev, info->agno, &info->low);
- trace_xfs_fsmap_high_key(mp, info->dev, info->agno,
+ trace_xfs_fsmap_low_key(mp, info->dev, pag->pag_agno,
+ &info->low);
+ trace_xfs_fsmap_high_key(mp, info->dev, pag->pag_agno,
&info->high);

error = query_fn(tp, info, &bt_cur, priv);
if (error)
- goto err;
+ break;

/*
* Set the AG low key to the start of the AG prior to
* moving on to the next AG.
*/
- if (info->agno == start_ag) {
+ if (pag->pag_agno == start_ag) {
info->low.rm_startblock = 0;
info->low.rm_owner = 0;
info->low.rm_offset = 0;
info->low.rm_flags = 0;
}
- }

- /* Report any gap at the end of the AG */
- info->last = true;
- error = query_fn(tp, info, &bt_cur, priv);
- if (error)
- goto err;
+ /*
+ * If this is the last AG, report any gap at the end of it
+ * before we drop the reference to the perag when the loop
+ * terminates.
+ */
+ if (pag->pag_agno == end_ag) {
+ info->last = true;
+ error = query_fn(tp, info, &bt_cur, priv);
+ if (error)
+ break;
+ }
+ info->pag = NULL;
+ }

-err:
if (bt_cur)
xfs_btree_del_cursor(bt_cur, error < 0 ? XFS_BTREE_ERROR :
XFS_BTREE_NOERROR);
@@ -673,6 +683,13 @@ __xfs_getfsmap_datadev(
xfs_trans_brelse(tp, info->agf_bp);
info->agf_bp = NULL;
}
+ if (info->pag) {
+ xfs_perag_put(info->pag);
+ info->pag = NULL;
+ } else if (pag) {
+ /* loop termination case */
+ xfs_perag_put(pag);
+ }

return error;
}
@@ -691,7 +708,7 @@ xfs_getfsmap_datadev_rmapbt_query(

/* Allocate cursor for this AG and query_range it. */
*curpp = xfs_rmapbt_init_cursor(tp->t_mountp, tp, info->agf_bp,
- info->agno);
+ info->pag->pag_agno);
return xfs_rmap_query_range(*curpp, &info->low, &info->high,
xfs_getfsmap_datadev_helper, info);
}
@@ -724,7 +741,7 @@ xfs_getfsmap_datadev_bnobt_query(

/* Allocate cursor for this AG and query_range it. */
*curpp = xfs_allocbt_init_cursor(tp->t_mountp, tp, info->agf_bp,
- info->agno, XFS_BTNUM_BNO);
+ info->pag->pag_agno, XFS_BTNUM_BNO);
key->ar_startblock = info->low.rm_startblock;
key[1].ar_startblock = info->high.rm_startblock;
return xfs_alloc_query_range(*curpp, key, &key[1],
@@ -937,7 +954,7 @@ xfs_getfsmap(

info.dev = handlers[i].dev;
info.last = false;
- info.agno = NULLAGNUMBER;
+ info.pag = NULL;
error = handlers[i].fn(tp, dkeys, &info);
if (error)
break;
--
2.31.1