[PATCH 10/27] xfs: create helpers to scan an allocation group

Darrick J. Wong
2017-09-21T00:18:41Z

Add some helpers to enable us to lock an AG's headers, create btree
cursors for all btrees in that allocation group, and clean up
afterwards.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
---
fs/xfs/scrub/common.c | 173 +++++++++++++++++++++++++++++++++++++++++++++++++
fs/xfs/scrub/common.h | 10 +++
fs/xfs/scrub/scrub.c | 4 +
fs/xfs/scrub/scrub.h | 21 ++++++
4 files changed, 208 insertions(+)

diff --git a/fs/xfs/scrub/common.c b/fs/xfs/scrub/common.c
index cf3f1365..1e80f23 100644
--- a/fs/xfs/scrub/common.c
+++ b/fs/xfs/scrub/common.c
@@ -44,6 +44,7 @@
#include "scrub/scrub.h"
#include "scrub/common.h"
#include "scrub/trace.h"
+#include "scrub/btree.h"

/* Common code for the metadata scrubbers. */

@@ -290,6 +291,178 @@ xfs_scrub_check_thoroughness(
return fs_ok;
}

+/*
+ * AG scrubbing
+ *
+ * These helpers facilitate locking an allocation group's header
+ * buffers, setting up cursors for all btrees that are present, and
+ * cleaning everything up once we're through.
+ */
+
+/* Grab all the headers for an AG. */
+int
+xfs_scrub_ag_read_headers(
+ struct xfs_scrub_context *sc,
+ xfs_agnumber_t agno,
+ struct xfs_buf **agi,
+ struct xfs_buf **agf,
+ struct xfs_buf **agfl)
+{
+ struct xfs_mount *mp = sc->mp;
+ int error;
+
+ error = xfs_ialloc_read_agi(mp, sc->tp, agno, agi);
+ if (error)
+ goto out;
+
+ error = xfs_alloc_read_agf(mp, sc->tp, agno, 0, agf);
+ if (error)
+ goto out;
+ if (!*agf) {
+ error = -ENOMEM;
+ goto out;
+ }
+
+ error = xfs_alloc_read_agfl(mp, sc->tp, agno, agfl);
+ if (error)
+ goto out;
+
+out:
+ return error;
+}
+
+/* Release all the AG btree cursors. */
+void
+xfs_scrub_ag_btcur_free(
+ struct xfs_scrub_ag *sa)
+{
+ if (sa->refc_cur)
+ xfs_btree_del_cursor(sa->refc_cur, XFS_BTREE_ERROR);
+ if (sa->rmap_cur)
+ xfs_btree_del_cursor(sa->rmap_cur, XFS_BTREE_ERROR);
+ if (sa->fino_cur)
+ xfs_btree_del_cursor(sa->fino_cur, XFS_BTREE_ERROR);
+ if (sa->ino_cur)
+ xfs_btree_del_cursor(sa->ino_cur, XFS_BTREE_ERROR);
+ if (sa->cnt_cur)
+ xfs_btree_del_cursor(sa->cnt_cur, XFS_BTREE_ERROR);
+ if (sa->bno_cur)
+ xfs_btree_del_cursor(sa->bno_cur, XFS_BTREE_ERROR);
+
+ sa->refc_cur = NULL;
+ sa->rmap_cur = NULL;
+ sa->fino_cur = NULL;
+ sa->ino_cur = NULL;
+ sa->bno_cur = NULL;
+ sa->cnt_cur = NULL;
+}
+
+/* Initialize all the btree cursors for an AG. */
+int
+xfs_scrub_ag_btcur_init(
+ struct xfs_scrub_context *sc,
+ struct xfs_scrub_ag *sa)
+{
+ struct xfs_mount *mp = sc->mp;
+ xfs_agnumber_t agno = sa->agno;
+
+ if (sa->agf_bp) {
+ /* Set up a bnobt cursor for cross-referencing. */
+ sa->bno_cur = xfs_allocbt_init_cursor(mp, sc->tp, sa->agf_bp,
+ agno, XFS_BTNUM_BNO);
+ if (!sa->bno_cur)
+ goto err;
+
+ /* Set up a cntbt cursor for cross-referencing. */
+ sa->cnt_cur = xfs_allocbt_init_cursor(mp, sc->tp, sa->agf_bp,
+ agno, XFS_BTNUM_CNT);
+ if (!sa->cnt_cur)
+ goto err;
+ }
+
+ /* Set up a inobt cursor for cross-referencing. */
+ if (sa->agi_bp) {
+ sa->ino_cur = xfs_inobt_init_cursor(mp, sc->tp, sa->agi_bp,
+ agno, XFS_BTNUM_INO);
+ if (!sa->ino_cur)
+ goto err;
+ }
+
+ /* Set up a finobt cursor for cross-referencing. */
+ if (sa->agi_bp && xfs_sb_version_hasfinobt(&mp->m_sb)) {
+ sa->fino_cur = xfs_inobt_init_cursor(mp, sc->tp, sa->agi_bp,
+ agno, XFS_BTNUM_FINO);
+ if (!sa->fino_cur)
+ goto err;
+ }
+
+ /* Set up a rmapbt cursor for cross-referencing. */
+ if (sa->agf_bp && xfs_sb_version_hasrmapbt(&mp->m_sb)) {
+ sa->rmap_cur = xfs_rmapbt_init_cursor(mp, sc->tp, sa->agf_bp,
+ agno);
+ if (!sa->rmap_cur)
+ goto err;
+ }
+
+ /* Set up a refcountbt cursor for cross-referencing. */
+ if (sa->agf_bp && xfs_sb_version_hasreflink(&mp->m_sb)) {
+ sa->refc_cur = xfs_refcountbt_init_cursor(mp, sc->tp,
+ sa->agf_bp, agno, NULL);
+ if (!sa->refc_cur)
+ goto err;
+ }
+
+ return 0;
+err:
+ return -ENOMEM;
+}
+
+/* Release the AG header context and btree cursors. */
+void
+xfs_scrub_ag_free(
+ struct xfs_scrub_context *sc,
+ struct xfs_scrub_ag *sa)
+{
+ xfs_scrub_ag_btcur_free(sa);
+ if (sa->agfl_bp) {
+ xfs_trans_brelse(sc->tp, sa->agfl_bp);
+ sa->agfl_bp = NULL;
+ }
+ if (sa->agf_bp) {
+ xfs_trans_brelse(sc->tp, sa->agf_bp);
+ sa->agf_bp = NULL;
+ }
+ if (sa->agi_bp) {
+ xfs_trans_brelse(sc->tp, sa->agi_bp);
+ sa->agi_bp = NULL;
+ }
+ sa->agno = NULLAGNUMBER;
+}
+
+/*
+ * For scrub, grab the AGI and the AGF headers, in that order. Locking
+ * order requires us to get the AGI before the AGF. We use the
+ * transaction to avoid deadlocking on crosslinked metadata buffers;
+ * either the caller passes one in (bmap scrub) or we have to create a
+ * transaction ourselves.
+ */
+int
+xfs_scrub_ag_init(
+ struct xfs_scrub_context *sc,
+ xfs_agnumber_t agno,
+ struct xfs_scrub_ag *sa)
+{
+ int error;
+
+ sa->agno = agno;
+ error = xfs_scrub_ag_read_headers(sc, agno, &sa->agi_bp,
+ &sa->agf_bp, &sa->agfl_bp);
+ if (error)
+ return error;
+
+ return xfs_scrub_ag_btcur_init(sc, sa);
+}
+
/* Per-scrubber setup functions */

/* Set us up with a transaction and an empty context. */
diff --git a/fs/xfs/scrub/common.h b/fs/xfs/scrub/common.h
index 9920488..105b7ad 100644
--- a/fs/xfs/scrub/common.h
+++ b/fs/xfs/scrub/common.h
@@ -93,4 +93,14 @@ bool xfs_scrub_check_thoroughness(struct xfs_scrub_context *sc, bool fs_ok);
/* Setup functions */
int xfs_scrub_setup_fs(struct xfs_scrub_context *sc, struct xfs_inode *ip);

+void xfs_scrub_ag_free(struct xfs_scrub_context *sc, struct xfs_scrub_ag *sa);
+int xfs_scrub_ag_init(struct xfs_scrub_context *sc, xfs_agnumber_t agno,
+ struct xfs_scrub_ag *sa);
+int xfs_scrub_ag_read_headers(struct xfs_scrub_context *sc, xfs_agnumber_t agno,
+ struct xfs_buf **agi, struct xfs_buf **agf,
+ struct xfs_buf **agfl);
+void xfs_scrub_ag_btcur_free(struct xfs_scrub_ag *sa);
+int xfs_scrub_ag_btcur_init(struct xfs_scrub_context *sc,
+ struct xfs_scrub_ag *sa);
+
#endif /* __XFS_SCRUB_COMMON_H__ */
diff --git a/fs/xfs/scrub/scrub.c b/fs/xfs/scrub/scrub.c
index 7936a23..bfc53b6 100644
--- a/fs/xfs/scrub/scrub.c
+++ b/fs/xfs/scrub/scrub.c
@@ -44,6 +44,8 @@
#include "scrub/scrub.h"
#include "scrub/common.h"
#include "scrub/trace.h"
+#include "scrub/scrub.h"
+#include "scrub/btree.h"

/*
* Online Scrub and Repair
@@ -145,6 +147,7 @@ xfs_scrub_teardown(
struct xfs_scrub_context *sc,
int error)
{
+ xfs_scrub_ag_free(sc, &sc->sa);
if (sc->tp) {
xfs_trans_cancel(sc->tp);
sc->tp = NULL;
@@ -225,6 +228,7 @@ xfs_scrub_metadata(
sc.sm = sm;
sc.ops = ops;
sc.try_harder = try_harder;
+ sc.sa.agno = NULLAGNUMBER;
error = sc.ops->setup(&sc, ip);
if (error)
goto out_teardown;
diff --git a/fs/xfs/scrub/scrub.h b/fs/xfs/scrub/scrub.h
index 2528039..291444f 100644
--- a/fs/xfs/scrub/scrub.h
+++ b/fs/xfs/scrub/scrub.h
@@ -29,6 +29,24 @@ struct xfs_scrub_meta_ops {
bool (*has)(struct xfs_sb *);
};

+/* Buffer pointers and btree cursors for an entire AG. */
+struct xfs_scrub_ag {
+ xfs_agnumber_t agno;
+
+ /* AG btree roots */
+ struct xfs_buf *agf_bp;
+ struct xfs_buf *agfl_bp;
+ struct xfs_buf *agi_bp;
+
+ /* AG btrees */
+ struct xfs_btree_cur *bno_cur;
+ struct xfs_btree_cur *cnt_cur;
+ struct xfs_btree_cur *ino_cur;
+ struct xfs_btree_cur *fino_cur;
+ struct xfs_btree_cur *rmap_cur;
+ struct xfs_btree_cur *refc_cur;
+};
+
struct xfs_scrub_context {
/* General scrub state. */
struct xfs_mount *mp;
@@ -37,6 +55,9 @@ struct xfs_scrub_context {
struct xfs_trans *tp;
struct xfs_inode *ip;
bool try_harder;
+
+ /* State tracking for single-AG operations. */
+ struct xfs_scrub_ag sa;
};

/* Metadata scrubbers */