[PATCH 4/4] xfs: implement online scrubbing of rtsummary info

Darrick J. Wong
2023-07-27T22:28:47Z

Finish the realtime summary scrubber by adding the functions we need to
compute a fresh copy of the rtsummary info and comparing it to the copy
on disk.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
---
fs/xfs/scrub/common.h | 18 +++
fs/xfs/scrub/rtbitmap.c | 4 -
fs/xfs/scrub/rtsummary.c | 254 ++++++++++++++++++++++++++++++++++++++++++----
fs/xfs/scrub/scrub.c | 9 +-
fs/xfs/scrub/scrub.h | 4 +
fs/xfs/scrub/trace.h | 34 ++++++
fs/xfs/xfs_trace.h | 3 +
7 files changed, 298 insertions(+), 28 deletions(-)

diff --git a/fs/xfs/scrub/common.h b/fs/xfs/scrub/common.h
index 6495a39e91230..5fe6d661d42d9 100644
--- a/fs/xfs/scrub/common.h
+++ b/fs/xfs/scrub/common.h
@@ -88,10 +88,16 @@ int xchk_setup_xattr(struct xfs_scrub *sc);
int xchk_setup_symlink(struct xfs_scrub *sc);
int xchk_setup_parent(struct xfs_scrub *sc);
#ifdef CONFIG_XFS_RT
-int xchk_setup_rt(struct xfs_scrub *sc);
+int xchk_setup_rtbitmap(struct xfs_scrub *sc);
+int xchk_setup_rtsummary(struct xfs_scrub *sc);
#else
static inline int
-xchk_setup_rt(struct xfs_scrub *sc)
+xchk_setup_rtbitmap(struct xfs_scrub *sc)
+{
+ return -ENOENT;
+}
+static inline int
+xchk_setup_rtsummary(struct xfs_scrub *sc)
{
return -ENOENT;
}
@@ -163,6 +169,14 @@ static inline bool xchk_skip_xref(struct xfs_scrub_metadata *sm)

int xchk_metadata_inode_forks(struct xfs_scrub *sc);

+/*
+ * Helper macros to allocate and format xfile description strings.
+ * Callers must kfree the pointer returned.
+ */
+#define xchk_xfile_descr(sc, fmt, ...) \
+ kasprintf(XCHK_GFP_FLAGS, "XFS (%s): " fmt, \
+ (sc)->mp->m_super->s_id, ##__VA_ARGS__)
+
/*
* Setting up a hook to wait for intents to drain is costly -- we have to take
* the CPU hotplug lock and force an i-cache flush on all CPUs once to set it
diff --git a/fs/xfs/scrub/rtbitmap.c b/fs/xfs/scrub/rtbitmap.c
index 0bf56d92d70a2..008ddb599e132 100644
--- a/fs/xfs/scrub/rtbitmap.c
+++ b/fs/xfs/scrub/rtbitmap.c
@@ -19,12 +19,12 @@

/* Set us up with the realtime metadata locked. */
int
-xchk_setup_rt(
+xchk_setup_rtbitmap(
struct xfs_scrub *sc)
{
int error;

- error = xchk_setup_fs(sc);
+ error = xchk_trans_alloc(sc, 0);
if (error)
return error;

diff --git a/fs/xfs/scrub/rtsummary.c b/fs/xfs/scrub/rtsummary.c
index f96d0c7c5fe03..437ed9acbb273 100644
--- a/fs/xfs/scrub/rtsummary.c
+++ b/fs/xfs/scrub/rtsummary.c
@@ -14,41 +14,251 @@
#include "xfs_log_format.h"
#include "xfs_trans.h"
#include "xfs_rtalloc.h"
+#include "xfs_bit.h"
+#include "xfs_bmap.h"
#include "scrub/scrub.h"
#include "scrub/common.h"
+#include "scrub/trace.h"
+#include "scrub/xfile.h"
+
+/*
+ * Realtime Summary
+ * ================
+ *
+ * We check the realtime summary by scanning the realtime bitmap file to create
+ * a new summary file incore, and then we compare the computed version against
+ * the ondisk version. We use the 'xfile' functionality to store this
+ * (potentially large) amount of data in pageable memory.
+ */
+
+/* Set us up to check the rtsummary file. */
+int
+xchk_setup_rtsummary(
+ struct xfs_scrub *sc)
+{
+ struct xfs_mount *mp = sc->mp;
+ char *descr;
+ int error;
+
+ /*
+ * Create an xfile to construct a new rtsummary file. The xfile allows
+ * us to avoid pinning kernel memory for this purpose.
+ */
+ descr = xchk_xfile_descr(sc, "realtime summary file");
+ error = xfile_create(descr, mp->m_rsumsize, &sc->xfile);
+ kfree(descr);
+ if (error)
+ return error;
+
+ error = xchk_trans_alloc(sc, 0);
+ if (error)
+ return error;
+
+ /* Allocate a memory buffer for the summary comparison. */
+ sc->buf = kvmalloc(mp->m_sb.sb_blocksize, XCHK_GFP_FLAGS);
+ if (!sc->buf)
+ return -ENOMEM;
+
+ error = xchk_install_live_inode(sc, mp->m_rsumip);
+ if (error)
+ return error;
+
+ /*
+ * Locking order requires us to take the rtbitmap first. We must be
+ * careful to unlock it ourselves when we are done with the rtbitmap
+ * file since the scrub infrastructure won't do that for us. Only
+ * then we can lock the rtsummary inode.
+ */
+ xfs_ilock(mp->m_rbmip, XFS_ILOCK_SHARED | XFS_ILOCK_RTBITMAP);
+ xchk_ilock(sc, XFS_ILOCK_EXCL | XFS_ILOCK_RTSUM);
+ return 0;
+}
+
+/* Helper functions to record suminfo words in an xfile. */
+
+typedef unsigned int xchk_rtsumoff_t;
+
+static inline int
+xfsum_load(
+ struct xfs_scrub *sc,
+ xchk_rtsumoff_t sumoff,
+ xfs_suminfo_t *info)
+{
+ return xfile_obj_load(sc->xfile, info, sizeof(xfs_suminfo_t),
+ sumoff << XFS_WORDLOG);
+}
+
+static inline int
+xfsum_store(
+ struct xfs_scrub *sc,
+ xchk_rtsumoff_t sumoff,
+ const xfs_suminfo_t info)
+{
+ return xfile_obj_store(sc->xfile, &info, sizeof(xfs_suminfo_t),
+ sumoff << XFS_WORDLOG);
+}
+
+static inline int
+xfsum_copyout(
+ struct xfs_scrub *sc,
+ xchk_rtsumoff_t sumoff,
+ xfs_suminfo_t *info,
+ unsigned int nr_words)
+{
+ return xfile_obj_load(sc->xfile, info, nr_words << XFS_WORDLOG,
+ sumoff << XFS_WORDLOG);
+}
+
+/* Update the summary file to reflect the free extent that we've accumulated. */
+STATIC int
+xchk_rtsum_record_free(
+ struct xfs_mount *mp,
+ struct xfs_trans *tp,
+ const struct xfs_rtalloc_rec *rec,
+ void *priv)
+{
+ struct xfs_scrub *sc = priv;
+ xfs_fileoff_t rbmoff;
+ xfs_rtblock_t rtbno;
+ xfs_filblks_t rtlen;
+ xchk_rtsumoff_t offs;
+ unsigned int lenlog;
+ xfs_suminfo_t v = 0;
+ int error = 0;
+
+ if (xchk_should_terminate(sc, &error))
+ return error;
+
+ /* Compute the relevant location in the rtsum file. */
+ rbmoff = XFS_BITTOBLOCK(mp, rec->ar_startext);
+ lenlog = XFS_RTBLOCKLOG(rec->ar_extcount);
+ offs = XFS_SUMOFFS(mp, lenlog, rbmoff);
+
+ rtbno = rec->ar_startext * mp->m_sb.sb_rextsize;
+ rtlen = rec->ar_extcount * mp->m_sb.sb_rextsize;
+
+ if (!xfs_verify_rtext(mp, rtbno, rtlen)) {
+ xchk_ino_xref_set_corrupt(sc, mp->m_rbmip->i_ino);
+ return -EFSCORRUPTED;
+ }
+
+ /* Bump the summary count. */
+ error = xfsum_load(sc, offs, &v);
+ if (error)
+ return error;
+
+ v++;
+ trace_xchk_rtsum_record_free(mp, rec->ar_startext, rec->ar_extcount,
+ lenlog, offs, v);
+
+ return xfsum_store(sc, offs, v);
+}
+
+/* Compute the realtime summary from the realtime bitmap. */
+STATIC int
+xchk_rtsum_compute(
+ struct xfs_scrub *sc)
+{
+ struct xfs_mount *mp = sc->mp;
+ unsigned long long rtbmp_bytes;
+
+ /* If the bitmap size doesn't match the computed size, bail. */
+ rtbmp_bytes = howmany_64(mp->m_sb.sb_rextents, NBBY);
+ if (roundup_64(rtbmp_bytes, mp->m_sb.sb_blocksize) !=
+ mp->m_rbmip->i_disk_size)
+ return -EFSCORRUPTED;
+
+ return xfs_rtalloc_query_all(sc->mp, sc->tp, xchk_rtsum_record_free,
+ sc);
+}
+
+/* Compare the rtsummary file against the one we computed. */
+STATIC int
+xchk_rtsum_compare(
+ struct xfs_scrub *sc)
+{
+ struct xfs_mount *mp = sc->mp;
+ struct xfs_buf *bp;
+ struct xfs_bmbt_irec map;
+ xfs_fileoff_t off;
+ xchk_rtsumoff_t sumoff = 0;
+ int nmap;
+
+ for (off = 0; off < XFS_B_TO_FSB(mp, mp->m_rsumsize); off++) {
+ int error = 0;
+
+ if (xchk_should_terminate(sc, &error))
+ return error;
+ if (sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT)
+ return 0;
+
+ /* Make sure we have a written extent. */
+ nmap = 1;
+ error = xfs_bmapi_read(mp->m_rsumip, off, 1, &map, &nmap,
+ XFS_DATA_FORK);
+ if (!xchk_fblock_process_error(sc, XFS_DATA_FORK, off, &error))
+ return error;
+
+ if (nmap != 1 || !xfs_bmap_is_written_extent(&map)) {
+ xchk_fblock_set_corrupt(sc, XFS_DATA_FORK, off);
+ return 0;
+ }
+
+ /* Read a block's worth of ondisk rtsummary file. */
+ error = xfs_rtbuf_get(mp, sc->tp, off, 1, &bp);
+ if (!xchk_fblock_process_error(sc, XFS_DATA_FORK, off, &error))
+ return error;
+
+ /* Read a block's worth of computed rtsummary file. */
+ error = xfsum_copyout(sc, sumoff, sc->buf, mp->m_blockwsize);
+ if (error) {
+ xfs_trans_brelse(sc->tp, bp);
+ return error;
+ }
+
+ if (memcmp(bp->b_addr, sc->buf,
+ mp->m_blockwsize << XFS_WORDLOG) != 0)
+ xchk_fblock_set_corrupt(sc, XFS_DATA_FORK, off);
+
+ xfs_trans_brelse(sc->tp, bp);
+ sumoff += mp->m_blockwsize;
+ }
+
+ return 0;
+}

/* Scrub the realtime summary. */
int
xchk_rtsummary(
struct xfs_scrub *sc)
{
- struct xfs_inode *rsumip = sc->mp->m_rsumip;
- struct xfs_inode *old_ip = sc->ip;
- uint old_ilock_flags = sc->ilock_flags;
+ struct xfs_mount *mp = sc->mp;
int error = 0;

- /*
- * We ILOCK'd the rt bitmap ip in the setup routine, now lock the
- * rt summary ip in compliance with the rt inode locking rules.
- *
- * Since we switch sc->ip to rsumip we have to save the old ilock
- * flags so that we don't mix up the inode state that @sc tracks.
- */
- sc->ip = rsumip;
- sc->ilock_flags = 0;
- xchk_ilock(sc, XFS_ILOCK_EXCL | XFS_ILOCK_RTSUM);
-
/* Invoke the fork scrubber. */
error = xchk_metadata_inode_forks(sc);
if (error || (sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT))
- goto out;
+ goto out_rbm;

- /* XXX: implement this some day */
- xchk_set_incomplete(sc);
-out:
- /* Switch back to the rtbitmap inode and lock flags. */
- xchk_iunlock(sc, XFS_ILOCK_EXCL | XFS_ILOCK_RTSUM);
- sc->ilock_flags = old_ilock_flags;
- sc->ip = old_ip;
+ /* Construct the new summary file from the rtbitmap. */
+ error = xchk_rtsum_compute(sc);
+ if (error == -EFSCORRUPTED) {
+ /*
+ * EFSCORRUPTED means the rtbitmap is corrupt, which is an xref
+ * error since we're checking the summary file.
+ */
+ xchk_ino_xref_set_corrupt(sc, mp->m_rbmip->i_ino);
+ error = 0;
+ goto out_rbm;
+ }
+ if (error)
+ goto out_rbm;
+
+ /* Does the computed summary file match the actual rtsummary file? */
+ error = xchk_rtsum_compare(sc);
+
+out_rbm:
+ /* Unlock the rtbitmap since we're done with it. */
+ xfs_iunlock(mp->m_rbmip, XFS_ILOCK_SHARED | XFS_ILOCK_RTBITMAP);
return error;
}
diff --git a/fs/xfs/scrub/scrub.c b/fs/xfs/scrub/scrub.c
index d2a91251add74..cd0ecb29c50c6 100644
--- a/fs/xfs/scrub/scrub.c
+++ b/fs/xfs/scrub/scrub.c
@@ -25,6 +25,7 @@
#include "scrub/repair.h"
#include "scrub/health.h"
#include "scrub/stats.h"
+#include "scrub/xfile.h"

/*
* Online Scrub and Repair
@@ -185,6 +186,10 @@ xchk_teardown(
}
if (sc->sm->sm_flags & XFS_SCRUB_IFLAG_REPAIR)
mnt_drop_write_file(sc->file);
+ if (sc->xfile) {
+ xfile_destroy(sc->xfile);
+ sc->xfile = NULL;
+ }
if (sc->buf) {
if (sc->buf_cleanup)
sc->buf_cleanup(sc->buf);
@@ -319,14 +324,14 @@ static const struct xchk_meta_ops meta_scrub_ops[] = {
},
[XFS_SCRUB_TYPE_RTBITMAP] = { /* realtime bitmap */
.type = ST_FS,
- .setup = xchk_setup_rt,
+ .setup = xchk_setup_rtbitmap,
.scrub = xchk_rtbitmap,
.has = xfs_has_realtime,
.repair = xrep_notsupported,
},
[XFS_SCRUB_TYPE_RTSUM] = { /* realtime summary */
.type = ST_FS,
- .setup = xchk_setup_rt,
+ .setup = xchk_setup_rtsummary,
.scrub = xchk_rtsummary,
.has = xfs_has_realtime,
.repair = xrep_notsupported,
diff --git a/fs/xfs/scrub/scrub.h b/fs/xfs/scrub/scrub.h
index e113f2f5c254b..f198c6cecef01 100644
--- a/fs/xfs/scrub/scrub.h
+++ b/fs/xfs/scrub/scrub.h
@@ -88,6 +88,10 @@ struct xfs_scrub {
*/
void (*buf_cleanup)(void *buf);

+ /* xfile used by the scrubbers; freed at teardown. */
+ struct xfile *xfile;
+
+ /* Lock flags for @ip. */
uint ilock_flags;

/* See the XCHK/XREP state flags below. */
diff --git a/fs/xfs/scrub/trace.h b/fs/xfs/scrub/trace.h
index e9d7159461428..83ed6e01c7df6 100644
--- a/fs/xfs/scrub/trace.h
+++ b/fs/xfs/scrub/trace.h
@@ -985,6 +985,40 @@ TRACE_EVENT(xfarray_sort_stats,
__entry->error)
);

+#ifdef CONFIG_XFS_RT
+TRACE_EVENT(xchk_rtsum_record_free,
+ TP_PROTO(struct xfs_mount *mp, xfs_rtblock_t start,
+ uint64_t len, unsigned int log, loff_t pos, xfs_suminfo_t v),
+ TP_ARGS(mp, start, len, log, pos, v),
+ TP_STRUCT__entry(
+ __field(dev_t, dev)
+ __field(dev_t, rtdev)
+ __field(xfs_rtblock_t, start)
+ __field(unsigned long long, len)
+ __field(unsigned int, log)
+ __field(loff_t, pos)
+ __field(xfs_suminfo_t, v)
+ ),
+ TP_fast_assign(
+ __entry->dev = mp->m_super->s_dev;
+ __entry->rtdev = mp->m_rtdev_targp->bt_dev;
+ __entry->start = start;
+ __entry->len = len;
+ __entry->log = log;
+ __entry->pos = pos;
+ __entry->v = v;
+ ),
+ TP_printk("dev %d:%d rtdev %d:%d rtx 0x%llx rtxcount 0x%llx log %u rsumpos 0x%llx sumcount %u",
+ MAJOR(__entry->dev), MINOR(__entry->dev),
+ MAJOR(__entry->rtdev), MINOR(__entry->rtdev),
+ __entry->start,
+ __entry->len,
+ __entry->log,
+ __entry->pos,
+ __entry->v)
+);
+#endif /* CONFIG_XFS_RT */
+
/* repair tracepoints */
#if IS_ENABLED(CONFIG_XFS_ONLINE_REPAIR)

diff --git a/fs/xfs/xfs_trace.h b/fs/xfs/xfs_trace.h
index f3cc204bb4bf6..36bd42ed9ec84 100644
--- a/fs/xfs/xfs_trace.h
+++ b/fs/xfs/xfs_trace.h
@@ -22,6 +22,9 @@
* daddr: physical block number in 512b blocks
* bbcount: number of blocks in a physical extent, in 512b blocks
*
+ * rtx: physical rt extent number for extent mappings
+ * rtxcount: number of rt extents in an extent mapping
+ *
* owner: reverse-mapping owner, usually inodes
*
* fileoff: file offset, in fs blocks