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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-08-07 13:11:22 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-08-07 13:11:22 +0000
commitb20732900e4636a467c0183a47f7396700f5f743 (patch)
tree42f079ff82e701ebcb76829974b4caca3e5b6798 /fs/xfs/scrub/iscan.c
parentAdding upstream version 6.8.12. (diff)
downloadlinux-b20732900e4636a467c0183a47f7396700f5f743.tar.xz
linux-b20732900e4636a467c0183a47f7396700f5f743.zip
Adding upstream version 6.9.7.upstream/6.9.7
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'fs/xfs/scrub/iscan.c')
-rw-r--r--fs/xfs/scrub/iscan.c767
1 files changed, 767 insertions, 0 deletions
diff --git a/fs/xfs/scrub/iscan.c b/fs/xfs/scrub/iscan.c
new file mode 100644
index 0000000000..ec3478bc50
--- /dev/null
+++ b/fs/xfs/scrub/iscan.c
@@ -0,0 +1,767 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2021-2024 Oracle. All Rights Reserved.
+ * Author: Darrick J. Wong <djwong@kernel.org>
+ */
+#include "xfs.h"
+#include "xfs_fs.h"
+#include "xfs_shared.h"
+#include "xfs_format.h"
+#include "xfs_trans_resv.h"
+#include "xfs_mount.h"
+#include "xfs_log_format.h"
+#include "xfs_trans.h"
+#include "xfs_inode.h"
+#include "xfs_btree.h"
+#include "xfs_ialloc.h"
+#include "xfs_ialloc_btree.h"
+#include "xfs_ag.h"
+#include "xfs_error.h"
+#include "xfs_bit.h"
+#include "xfs_icache.h"
+#include "scrub/scrub.h"
+#include "scrub/iscan.h"
+#include "scrub/common.h"
+#include "scrub/trace.h"
+
+/*
+ * Live File Scan
+ * ==============
+ *
+ * Live file scans walk every inode in a live filesystem. This is more or
+ * less like a regular iwalk, except that when we're advancing the scan cursor,
+ * we must ensure that inodes cannot be added or deleted anywhere between the
+ * old cursor value and the new cursor value. If we're advancing the cursor
+ * by one inode, the caller must hold that inode; if we're finding the next
+ * inode to scan, we must grab the AGI and hold it until we've updated the
+ * scan cursor.
+ *
+ * Callers are expected to use this code to scan all files in the filesystem to
+ * construct a new metadata index of some kind. The scan races against other
+ * live updates, which means there must be a provision to update the new index
+ * when updates are made to inodes that already been scanned. The iscan lock
+ * can be used in live update hook code to stop the scan and protect this data
+ * structure.
+ *
+ * To keep the new index up to date with other metadata updates being made to
+ * the live filesystem, it is assumed that the caller will add hooks as needed
+ * to be notified when a metadata update occurs. The inode scanner must tell
+ * the hook code when an inode has been visited with xchk_iscan_mark_visit.
+ * Hook functions can use xchk_iscan_want_live_update to decide if the
+ * scanner's observations must be updated.
+ */
+
+/*
+ * If the inobt record @rec covers @iscan->skip_ino, mark the inode free so
+ * that the scan ignores that inode.
+ */
+STATIC void
+xchk_iscan_mask_skipino(
+ struct xchk_iscan *iscan,
+ struct xfs_perag *pag,
+ struct xfs_inobt_rec_incore *rec,
+ xfs_agino_t lastrecino)
+{
+ struct xfs_scrub *sc = iscan->sc;
+ struct xfs_mount *mp = sc->mp;
+ xfs_agnumber_t skip_agno = XFS_INO_TO_AGNO(mp, iscan->skip_ino);
+ xfs_agnumber_t skip_agino = XFS_INO_TO_AGINO(mp, iscan->skip_ino);
+
+ if (pag->pag_agno != skip_agno)
+ return;
+ if (skip_agino < rec->ir_startino)
+ return;
+ if (skip_agino > lastrecino)
+ return;
+
+ rec->ir_free |= xfs_inobt_maskn(skip_agino - rec->ir_startino, 1);
+}
+
+/*
+ * Set *cursor to the next allocated inode after whatever it's set to now.
+ * If there are no more inodes in this AG, cursor is set to NULLAGINO.
+ */
+STATIC int
+xchk_iscan_find_next(
+ struct xchk_iscan *iscan,
+ struct xfs_buf *agi_bp,
+ struct xfs_perag *pag,
+ xfs_inofree_t *allocmaskp,
+ xfs_agino_t *cursor,
+ uint8_t *nr_inodesp)
+{
+ struct xfs_scrub *sc = iscan->sc;
+ struct xfs_inobt_rec_incore rec;
+ struct xfs_btree_cur *cur;
+ struct xfs_mount *mp = sc->mp;
+ struct xfs_trans *tp = sc->tp;
+ xfs_agnumber_t agno = pag->pag_agno;
+ xfs_agino_t lastino = NULLAGINO;
+ xfs_agino_t first, last;
+ xfs_agino_t agino = *cursor;
+ int has_rec;
+ int error;
+
+ /* If the cursor is beyond the end of this AG, move to the next one. */
+ xfs_agino_range(mp, agno, &first, &last);
+ if (agino > last) {
+ *cursor = NULLAGINO;
+ return 0;
+ }
+
+ /*
+ * Look up the inode chunk for the current cursor position. If there
+ * is no chunk here, we want the next one.
+ */
+ cur = xfs_inobt_init_cursor(pag, tp, agi_bp);
+ error = xfs_inobt_lookup(cur, agino, XFS_LOOKUP_LE, &has_rec);
+ if (!error && !has_rec)
+ error = xfs_btree_increment(cur, 0, &has_rec);
+ for (; !error; error = xfs_btree_increment(cur, 0, &has_rec)) {
+ xfs_inofree_t allocmask;
+
+ /*
+ * If we've run out of inobt records in this AG, move the
+ * cursor on to the next AG and exit. The caller can try
+ * again with the next AG.
+ */
+ if (!has_rec) {
+ *cursor = NULLAGINO;
+ break;
+ }
+
+ error = xfs_inobt_get_rec(cur, &rec, &has_rec);
+ if (error)
+ break;
+ if (!has_rec) {
+ error = -EFSCORRUPTED;
+ break;
+ }
+
+ /* Make sure that we always move forward. */
+ if (lastino != NULLAGINO &&
+ XFS_IS_CORRUPT(mp, lastino >= rec.ir_startino)) {
+ error = -EFSCORRUPTED;
+ break;
+ }
+ lastino = rec.ir_startino + XFS_INODES_PER_CHUNK - 1;
+
+ /*
+ * If this record only covers inodes that come before the
+ * cursor, advance to the next record.
+ */
+ if (rec.ir_startino + XFS_INODES_PER_CHUNK <= agino)
+ continue;
+
+ if (iscan->skip_ino)
+ xchk_iscan_mask_skipino(iscan, pag, &rec, lastino);
+
+ /*
+ * If the incoming lookup put us in the middle of an inobt
+ * record, mark it and the previous inodes "free" so that the
+ * search for allocated inodes will start at the cursor.
+ * We don't care about ir_freecount here.
+ */
+ if (agino >= rec.ir_startino)
+ rec.ir_free |= xfs_inobt_maskn(0,
+ agino + 1 - rec.ir_startino);
+
+ /*
+ * If there are allocated inodes in this chunk, find them
+ * and update the scan cursor.
+ */
+ allocmask = ~rec.ir_free;
+ if (hweight64(allocmask) > 0) {
+ int next = xfs_lowbit64(allocmask);
+
+ ASSERT(next >= 0);
+ *cursor = rec.ir_startino + next;
+ *allocmaskp = allocmask >> next;
+ *nr_inodesp = XFS_INODES_PER_CHUNK - next;
+ break;
+ }
+ }
+
+ xfs_btree_del_cursor(cur, error);
+ return error;
+}
+
+/*
+ * Advance both the scan and the visited cursors.
+ *
+ * The inumber address space for a given filesystem is sparse, which means that
+ * the scan cursor can jump a long ways in a single iter() call. There are no
+ * inodes in these sparse areas, so we must move the visited cursor forward at
+ * the same time so that the scan user can receive live updates for inodes that
+ * may get created once we release the AGI buffer.
+ */
+static inline void
+xchk_iscan_move_cursor(
+ struct xchk_iscan *iscan,
+ xfs_agnumber_t agno,
+ xfs_agino_t agino)
+{
+ struct xfs_scrub *sc = iscan->sc;
+ struct xfs_mount *mp = sc->mp;
+ xfs_ino_t cursor, visited;
+
+ BUILD_BUG_ON(XFS_MAXINUMBER == NULLFSINO);
+
+ /*
+ * Special-case ino == 0 here so that we never set visited_ino to
+ * NULLFSINO when wrapping around EOFS, for that will let through all
+ * live updates.
+ */
+ cursor = XFS_AGINO_TO_INO(mp, agno, agino);
+ if (cursor == 0)
+ visited = XFS_MAXINUMBER;
+ else
+ visited = cursor - 1;
+
+ mutex_lock(&iscan->lock);
+ iscan->cursor_ino = cursor;
+ iscan->__visited_ino = visited;
+ trace_xchk_iscan_move_cursor(iscan);
+ mutex_unlock(&iscan->lock);
+}
+
+/*
+ * Prepare to return agno/agino to the iscan caller by moving the lastino
+ * cursor to the previous inode. Do this while we still hold the AGI so that
+ * no other threads can create or delete inodes in this AG.
+ */
+static inline void
+xchk_iscan_finish(
+ struct xchk_iscan *iscan)
+{
+ mutex_lock(&iscan->lock);
+ iscan->cursor_ino = NULLFSINO;
+
+ /* All live updates will be applied from now on */
+ iscan->__visited_ino = NULLFSINO;
+
+ mutex_unlock(&iscan->lock);
+}
+
+/*
+ * Advance ino to the next inode that the inobt thinks is allocated, being
+ * careful to jump to the next AG if we've reached the right end of this AG's
+ * inode btree. Advancing ino effectively means that we've pushed the inode
+ * scan forward, so set the iscan cursor to (ino - 1) so that our live update
+ * predicates will track inode allocations in that part of the inode number
+ * key space once we release the AGI buffer.
+ *
+ * Returns 1 if there's a new inode to examine, 0 if we've run out of inodes,
+ * -ECANCELED if the live scan aborted, or the usual negative errno.
+ */
+STATIC int
+xchk_iscan_advance(
+ struct xchk_iscan *iscan,
+ struct xfs_perag **pagp,
+ struct xfs_buf **agi_bpp,
+ xfs_inofree_t *allocmaskp,
+ uint8_t *nr_inodesp)
+{
+ struct xfs_scrub *sc = iscan->sc;
+ struct xfs_mount *mp = sc->mp;
+ struct xfs_buf *agi_bp;
+ struct xfs_perag *pag;
+ xfs_agnumber_t agno;
+ xfs_agino_t agino;
+ int ret;
+
+ ASSERT(iscan->cursor_ino >= iscan->__visited_ino);
+
+ do {
+ if (xchk_iscan_aborted(iscan))
+ return -ECANCELED;
+
+ agno = XFS_INO_TO_AGNO(mp, iscan->cursor_ino);
+ pag = xfs_perag_get(mp, agno);
+ if (!pag)
+ return -ECANCELED;
+
+ ret = xfs_ialloc_read_agi(pag, sc->tp, &agi_bp);
+ if (ret)
+ goto out_pag;
+
+ agino = XFS_INO_TO_AGINO(mp, iscan->cursor_ino);
+ ret = xchk_iscan_find_next(iscan, agi_bp, pag, allocmaskp,
+ &agino, nr_inodesp);
+ if (ret)
+ goto out_buf;
+
+ if (agino != NULLAGINO) {
+ /*
+ * Found the next inode in this AG, so return it along
+ * with the AGI buffer and the perag structure to
+ * ensure it cannot go away.
+ */
+ xchk_iscan_move_cursor(iscan, agno, agino);
+ *agi_bpp = agi_bp;
+ *pagp = pag;
+ return 1;
+ }
+
+ /*
+ * Did not find any more inodes in this AG, move on to the next
+ * AG.
+ */
+ agno = (agno + 1) % mp->m_sb.sb_agcount;
+ xchk_iscan_move_cursor(iscan, agno, 0);
+ xfs_trans_brelse(sc->tp, agi_bp);
+ xfs_perag_put(pag);
+
+ trace_xchk_iscan_advance_ag(iscan);
+ } while (iscan->cursor_ino != iscan->scan_start_ino);
+
+ xchk_iscan_finish(iscan);
+ return 0;
+
+out_buf:
+ xfs_trans_brelse(sc->tp, agi_bp);
+out_pag:
+ xfs_perag_put(pag);
+ return ret;
+}
+
+/*
+ * Grabbing the inode failed, so we need to back up the scan and ask the caller
+ * to try to _advance the scan again. Returns -EBUSY if we've run out of retry
+ * opportunities, -ECANCELED if the process has a fatal signal pending, or
+ * -EAGAIN if we should try again.
+ */
+STATIC int
+xchk_iscan_iget_retry(
+ struct xchk_iscan *iscan,
+ bool wait)
+{
+ ASSERT(iscan->cursor_ino == iscan->__visited_ino + 1);
+
+ if (!iscan->iget_timeout ||
+ time_is_before_jiffies(iscan->__iget_deadline))
+ return -EBUSY;
+
+ if (wait) {
+ unsigned long relax;
+
+ /*
+ * Sleep for a period of time to let the rest of the system
+ * catch up. If we return early, someone sent a kill signal to
+ * the calling process.
+ */
+ relax = msecs_to_jiffies(iscan->iget_retry_delay);
+ trace_xchk_iscan_iget_retry_wait(iscan);
+
+ if (schedule_timeout_killable(relax) ||
+ xchk_iscan_aborted(iscan))
+ return -ECANCELED;
+ }
+
+ iscan->cursor_ino--;
+ return -EAGAIN;
+}
+
+/*
+ * Grab an inode as part of an inode scan. While scanning this inode, the
+ * caller must ensure that no other threads can modify the inode until a call
+ * to xchk_iscan_visit succeeds.
+ *
+ * Returns the number of incore inodes grabbed; -EAGAIN if the caller should
+ * call again xchk_iscan_advance; -EBUSY if we couldn't grab an inode;
+ * -ECANCELED if there's a fatal signal pending; or some other negative errno.
+ */
+STATIC int
+xchk_iscan_iget(
+ struct xchk_iscan *iscan,
+ struct xfs_perag *pag,
+ struct xfs_buf *agi_bp,
+ xfs_inofree_t allocmask,
+ uint8_t nr_inodes)
+{
+ struct xfs_scrub *sc = iscan->sc;
+ struct xfs_mount *mp = sc->mp;
+ xfs_ino_t ino = iscan->cursor_ino;
+ unsigned int idx = 0;
+ unsigned int i;
+ int error;
+
+ ASSERT(iscan->__inodes[0] == NULL);
+
+ /* Fill the first slot in the inode array. */
+ error = xfs_iget(sc->mp, sc->tp, ino, XFS_IGET_NORETRY, 0,
+ &iscan->__inodes[idx]);
+
+ trace_xchk_iscan_iget(iscan, error);
+
+ if (error == -ENOENT || error == -EAGAIN) {
+ xfs_trans_brelse(sc->tp, agi_bp);
+ xfs_perag_put(pag);
+
+ /*
+ * It's possible that this inode has lost all of its links but
+ * hasn't yet been inactivated. If we don't have a transaction
+ * or it's not writable, flush the inodegc workers and wait.
+ */
+ xfs_inodegc_flush(mp);
+ return xchk_iscan_iget_retry(iscan, true);
+ }
+
+ if (error == -EINVAL) {
+ xfs_trans_brelse(sc->tp, agi_bp);
+ xfs_perag_put(pag);
+
+ /*
+ * We thought the inode was allocated, but the inode btree
+ * lookup failed, which means that it was freed since the last
+ * time we advanced the cursor. Back up and try again. This
+ * should never happen since still hold the AGI buffer from the
+ * inobt check, but we need to be careful about infinite loops.
+ */
+ return xchk_iscan_iget_retry(iscan, false);
+ }
+
+ if (error) {
+ xfs_trans_brelse(sc->tp, agi_bp);
+ xfs_perag_put(pag);
+ return error;
+ }
+ idx++;
+ ino++;
+ allocmask >>= 1;
+
+ /*
+ * Now that we've filled the first slot in __inodes, try to fill the
+ * rest of the batch with consecutively ordered inodes. to reduce the
+ * number of _iter calls. Make a bitmap of unallocated inodes from the
+ * zeroes in the inuse bitmap; these inodes will not be scanned, but
+ * the _want_live_update predicate will pass through all live updates.
+ *
+ * If we can't iget an allocated inode, stop and return what we have.
+ */
+ mutex_lock(&iscan->lock);
+ iscan->__batch_ino = ino - 1;
+ iscan->__skipped_inomask = 0;
+ mutex_unlock(&iscan->lock);
+
+ for (i = 1; i < nr_inodes; i++, ino++, allocmask >>= 1) {
+ if (!(allocmask & 1)) {
+ ASSERT(!(iscan->__skipped_inomask & (1ULL << i)));
+
+ mutex_lock(&iscan->lock);
+ iscan->cursor_ino = ino;
+ iscan->__skipped_inomask |= (1ULL << i);
+ mutex_unlock(&iscan->lock);
+ continue;
+ }
+
+ ASSERT(iscan->__inodes[idx] == NULL);
+
+ error = xfs_iget(sc->mp, sc->tp, ino, XFS_IGET_NORETRY, 0,
+ &iscan->__inodes[idx]);
+ if (error)
+ break;
+
+ mutex_lock(&iscan->lock);
+ iscan->cursor_ino = ino;
+ mutex_unlock(&iscan->lock);
+ idx++;
+ }
+
+ trace_xchk_iscan_iget_batch(sc->mp, iscan, nr_inodes, idx);
+ xfs_trans_brelse(sc->tp, agi_bp);
+ xfs_perag_put(pag);
+ return idx;
+}
+
+/*
+ * Advance the visit cursor to reflect skipped inodes beyond whatever we
+ * scanned.
+ */
+STATIC void
+xchk_iscan_finish_batch(
+ struct xchk_iscan *iscan)
+{
+ xfs_ino_t highest_skipped;
+
+ mutex_lock(&iscan->lock);
+
+ if (iscan->__batch_ino != NULLFSINO) {
+ highest_skipped = iscan->__batch_ino +
+ xfs_highbit64(iscan->__skipped_inomask);
+ iscan->__visited_ino = max(iscan->__visited_ino,
+ highest_skipped);
+
+ trace_xchk_iscan_skip(iscan);
+ }
+
+ iscan->__batch_ino = NULLFSINO;
+ iscan->__skipped_inomask = 0;
+
+ mutex_unlock(&iscan->lock);
+}
+
+/*
+ * Advance the inode scan cursor to the next allocated inode and return up to
+ * 64 consecutive allocated inodes starting with the cursor position.
+ */
+STATIC int
+xchk_iscan_iter_batch(
+ struct xchk_iscan *iscan)
+{
+ struct xfs_scrub *sc = iscan->sc;
+ int ret;
+
+ xchk_iscan_finish_batch(iscan);
+
+ if (iscan->iget_timeout)
+ iscan->__iget_deadline = jiffies +
+ msecs_to_jiffies(iscan->iget_timeout);
+
+ do {
+ struct xfs_buf *agi_bp = NULL;
+ struct xfs_perag *pag = NULL;
+ xfs_inofree_t allocmask = 0;
+ uint8_t nr_inodes = 0;
+
+ ret = xchk_iscan_advance(iscan, &pag, &agi_bp, &allocmask,
+ &nr_inodes);
+ if (ret != 1)
+ return ret;
+
+ if (xchk_iscan_aborted(iscan)) {
+ xfs_trans_brelse(sc->tp, agi_bp);
+ xfs_perag_put(pag);
+ ret = -ECANCELED;
+ break;
+ }
+
+ ret = xchk_iscan_iget(iscan, pag, agi_bp, allocmask, nr_inodes);
+ } while (ret == -EAGAIN);
+
+ return ret;
+}
+
+/*
+ * Advance the inode scan cursor to the next allocated inode and return the
+ * incore inode structure associated with it.
+ *
+ * Returns 1 if there's a new inode to examine, 0 if we've run out of inodes,
+ * -ECANCELED if the live scan aborted, -EBUSY if the incore inode could not be
+ * grabbed, or the usual negative errno.
+ *
+ * If the function returns -EBUSY and the caller can handle skipping an inode,
+ * it may call this function again to continue the scan with the next allocated
+ * inode.
+ */
+int
+xchk_iscan_iter(
+ struct xchk_iscan *iscan,
+ struct xfs_inode **ipp)
+{
+ unsigned int i;
+ int error;
+
+ /* Find a cached inode, or go get another batch. */
+ for (i = 0; i < XFS_INODES_PER_CHUNK; i++) {
+ if (iscan->__inodes[i])
+ goto foundit;
+ }
+
+ error = xchk_iscan_iter_batch(iscan);
+ if (error <= 0)
+ return error;
+
+ ASSERT(iscan->__inodes[0] != NULL);
+ i = 0;
+
+foundit:
+ /* Give the caller our reference. */
+ *ipp = iscan->__inodes[i];
+ iscan->__inodes[i] = NULL;
+ return 1;
+}
+
+/* Clean up an xfs_iscan_iter call by dropping any inodes that we still hold. */
+void
+xchk_iscan_iter_finish(
+ struct xchk_iscan *iscan)
+{
+ struct xfs_scrub *sc = iscan->sc;
+ unsigned int i;
+
+ for (i = 0; i < XFS_INODES_PER_CHUNK; i++) {
+ if (iscan->__inodes[i]) {
+ xchk_irele(sc, iscan->__inodes[i]);
+ iscan->__inodes[i] = NULL;
+ }
+ }
+}
+
+/* Mark this inode scan finished and release resources. */
+void
+xchk_iscan_teardown(
+ struct xchk_iscan *iscan)
+{
+ xchk_iscan_iter_finish(iscan);
+ xchk_iscan_finish(iscan);
+ mutex_destroy(&iscan->lock);
+}
+
+/* Pick an AG from which to start a scan. */
+static inline xfs_ino_t
+xchk_iscan_rotor(
+ struct xfs_mount *mp)
+{
+ static atomic_t agi_rotor;
+ unsigned int r = atomic_inc_return(&agi_rotor) - 1;
+
+ /*
+ * Rotoring *backwards* through the AGs, so we add one here before
+ * subtracting from the agcount to arrive at an AG number.
+ */
+ r = (r % mp->m_sb.sb_agcount) + 1;
+
+ return XFS_AGINO_TO_INO(mp, mp->m_sb.sb_agcount - r, 0);
+}
+
+/*
+ * Set ourselves up to start an inode scan. If the @iget_timeout and
+ * @iget_retry_delay parameters are set, the scan will try to iget each inode
+ * for @iget_timeout milliseconds. If an iget call indicates that the inode is
+ * waiting to be inactivated, the CPU will relax for @iget_retry_delay
+ * milliseconds after pushing the inactivation workers.
+ */
+void
+xchk_iscan_start(
+ struct xfs_scrub *sc,
+ unsigned int iget_timeout,
+ unsigned int iget_retry_delay,
+ struct xchk_iscan *iscan)
+{
+ xfs_ino_t start_ino;
+
+ start_ino = xchk_iscan_rotor(sc->mp);
+
+ iscan->__batch_ino = NULLFSINO;
+ iscan->__skipped_inomask = 0;
+
+ iscan->sc = sc;
+ clear_bit(XCHK_ISCAN_OPSTATE_ABORTED, &iscan->__opstate);
+ iscan->iget_timeout = iget_timeout;
+ iscan->iget_retry_delay = iget_retry_delay;
+ iscan->__visited_ino = start_ino;
+ iscan->cursor_ino = start_ino;
+ iscan->scan_start_ino = start_ino;
+ mutex_init(&iscan->lock);
+ memset(iscan->__inodes, 0, sizeof(iscan->__inodes));
+
+ trace_xchk_iscan_start(iscan, start_ino);
+}
+
+/*
+ * Mark this inode as having been visited. Callers must hold a sufficiently
+ * exclusive lock on the inode to prevent concurrent modifications.
+ */
+void
+xchk_iscan_mark_visited(
+ struct xchk_iscan *iscan,
+ struct xfs_inode *ip)
+{
+ mutex_lock(&iscan->lock);
+ iscan->__visited_ino = ip->i_ino;
+ trace_xchk_iscan_visit(iscan);
+ mutex_unlock(&iscan->lock);
+}
+
+/*
+ * Did we skip this inode because it wasn't allocated when we loaded the batch?
+ * If so, it is newly allocated and will not be scanned. All live updates to
+ * this inode must be passed to the caller to maintain scan correctness.
+ */
+static inline bool
+xchk_iscan_skipped(
+ const struct xchk_iscan *iscan,
+ xfs_ino_t ino)
+{
+ if (iscan->__batch_ino == NULLFSINO)
+ return false;
+ if (ino < iscan->__batch_ino)
+ return false;
+ if (ino >= iscan->__batch_ino + XFS_INODES_PER_CHUNK)
+ return false;
+
+ return iscan->__skipped_inomask & (1ULL << (ino - iscan->__batch_ino));
+}
+
+/*
+ * Do we need a live update for this inode? This is true if the scanner thread
+ * has visited this inode and the scan hasn't been aborted due to errors.
+ * Callers must hold a sufficiently exclusive lock on the inode to prevent
+ * scanners from reading any inode metadata.
+ */
+bool
+xchk_iscan_want_live_update(
+ struct xchk_iscan *iscan,
+ xfs_ino_t ino)
+{
+ bool ret = false;
+
+ if (xchk_iscan_aborted(iscan))
+ return false;
+
+ mutex_lock(&iscan->lock);
+
+ trace_xchk_iscan_want_live_update(iscan, ino);
+
+ /* Scan is finished, caller should receive all updates. */
+ if (iscan->__visited_ino == NULLFSINO) {
+ ret = true;
+ goto unlock;
+ }
+
+ /*
+ * No inodes have been visited yet, so the visited cursor points at the
+ * start of the scan range. The caller should not receive any updates.
+ */
+ if (iscan->scan_start_ino == iscan->__visited_ino) {
+ ret = false;
+ goto unlock;
+ }
+
+ /*
+ * This inode was not allocated at the time of the iscan batch.
+ * The caller should receive all updates.
+ */
+ if (xchk_iscan_skipped(iscan, ino)) {
+ ret = true;
+ goto unlock;
+ }
+
+ /*
+ * The visited cursor hasn't yet wrapped around the end of the FS. If
+ * @ino is inside the starred range, the caller should receive updates:
+ *
+ * 0 ------------ S ************ V ------------ EOFS
+ */
+ if (iscan->scan_start_ino <= iscan->__visited_ino) {
+ if (ino >= iscan->scan_start_ino &&
+ ino <= iscan->__visited_ino)
+ ret = true;
+
+ goto unlock;
+ }
+
+ /*
+ * The visited cursor wrapped around the end of the FS. If @ino is
+ * inside the starred range, the caller should receive updates:
+ *
+ * 0 ************ V ------------ S ************ EOFS
+ */
+ if (ino >= iscan->scan_start_ino || ino <= iscan->__visited_ino)
+ ret = true;
+
+unlock:
+ mutex_unlock(&iscan->lock);
+ return ret;
+}