[PATCH 24/24] xfs: remove unusued old inode reclaim code

Dave Chinner
2019-08-01T02:18:18Z

From: Dave Chinner <dchinner@redhat.com>

We don't use the custom AG radix tree walker, the reclaim radix tree
tag, the reclaimable inode counters, etc, so remove the all now.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
---
fs/xfs/xfs_icache.c | 410 +-------------------------------------------
fs/xfs/xfs_icache.h | 7 +-
fs/xfs/xfs_mount.h | 2 -
fs/xfs/xfs_super.c | 1 -
4 files changed, 3 insertions(+), 417 deletions(-)

diff --git a/fs/xfs/xfs_icache.c b/fs/xfs/xfs_icache.c
index 891fe3795c8f..ad04de119ac1 100644
--- a/fs/xfs/xfs_icache.c
+++ b/fs/xfs/xfs_icache.c
@@ -139,81 +139,6 @@ xfs_inode_free(
__xfs_inode_free(ip);
}

-static void
-xfs_perag_set_reclaim_tag(
- struct xfs_perag *pag)
-{
- struct xfs_mount *mp = pag->pag_mount;
-
- lockdep_assert_held(&pag->pag_ici_lock);
- if (pag->pag_ici_reclaimable++)
- return;
-
- /* propagate the reclaim tag up into the perag radix tree */
- spin_lock(&mp->m_perag_lock);
- radix_tree_tag_set(&mp->m_perag_tree, pag->pag_agno,
- XFS_ICI_RECLAIM_TAG);
- spin_unlock(&mp->m_perag_lock);
-
- trace_xfs_perag_set_reclaim(mp, pag->pag_agno, -1, _RET_IP_);
-}
-
-static void
-xfs_perag_clear_reclaim_tag(
- struct xfs_perag *pag)
-{
- struct xfs_mount *mp = pag->pag_mount;
-
- lockdep_assert_held(&pag->pag_ici_lock);
- if (--pag->pag_ici_reclaimable)
- return;
-
- /* clear the reclaim tag from the perag radix tree */
- spin_lock(&mp->m_perag_lock);
- radix_tree_tag_clear(&mp->m_perag_tree, pag->pag_agno,
- XFS_ICI_RECLAIM_TAG);
- spin_unlock(&mp->m_perag_lock);
- trace_xfs_perag_clear_reclaim(mp, pag->pag_agno, -1, _RET_IP_);
-}
-
-
-/*
- * We set the inode flag atomically with the radix tree tag.
- * Once we get tag lookups on the radix tree, this inode flag
- * can go away.
- */
-void
-xfs_inode_set_reclaim_tag(
- struct xfs_inode *ip)
-{
- struct xfs_mount *mp = ip->i_mount;
- struct xfs_perag *pag;
-
- pag = xfs_perag_get(mp, XFS_INO_TO_AGNO(mp, ip->i_ino));
- spin_lock(&pag->pag_ici_lock);
- spin_lock(&ip->i_flags_lock);
-
- radix_tree_tag_set(&pag->pag_ici_root, XFS_INO_TO_AGINO(mp, ip->i_ino),
- XFS_ICI_RECLAIM_TAG);
- xfs_perag_set_reclaim_tag(pag);
- __xfs_iflags_set(ip, XFS_IRECLAIMABLE);
-
- spin_unlock(&ip->i_flags_lock);
- spin_unlock(&pag->pag_ici_lock);
- xfs_perag_put(pag);
-}
-
-STATIC void
-xfs_inode_clear_reclaim_tag(
- struct xfs_perag *pag,
- xfs_ino_t ino)
-{
- radix_tree_tag_clear(&pag->pag_ici_root,
- XFS_INO_TO_AGINO(pag->pag_mount, ino),
- XFS_ICI_RECLAIM_TAG);
- xfs_perag_clear_reclaim_tag(pag);
-}
-
static void
xfs_inew_wait(
struct xfs_inode *ip)
@@ -397,17 +322,15 @@ xfs_iget_cache_hit(
goto out_error;
}

- spin_lock(&pag->pag_ici_lock);
- spin_lock(&ip->i_flags_lock);

/*
* Clear the per-lifetime state in the inode as we are now
* effectively a new inode and need to return to the initial
* state before reuse occurs.
*/
+ spin_lock(&ip->i_flags_lock);
ip->i_flags &= ~XFS_IRECLAIM_RESET_FLAGS;
ip->i_flags |= XFS_INEW;
- xfs_inode_clear_reclaim_tag(pag, ip->i_ino);
inode->i_state = I_NEW;
ip->i_sick = 0;
ip->i_checked = 0;
@@ -416,7 +339,6 @@ xfs_iget_cache_hit(
init_rwsem(&inode->i_rwsem);

spin_unlock(&ip->i_flags_lock);
- spin_unlock(&pag->pag_ici_lock);
} else {
/* If the VFS inode is being torn down, pause and try again. */
if (!igrab(inode)) {
@@ -967,336 +889,6 @@ xfs_inode_ag_iterator_tag(
return last_error;
}

-/*
- * Grab the inode for reclaim.
- *
- * Return false if we aren't going to reclaim it, true if it is a reclaim
- * candidate.
- *
- * If the inode is clean or unreclaimable, return NULLCOMMITLSN to tell the
- * caller it does not require flushing. Otherwise return the log item lsn of the
- * inode so the caller can determine it's inode flush target. If we get the
- * clean/dirty state wrong then it will be sorted in xfs_reclaim_inode() once we
- * have locks held.
- */
-STATIC bool
-xfs_reclaim_inode_grab(
- struct xfs_inode *ip,
- int flags,
- xfs_lsn_t *lsn)
-{
- ASSERT(rcu_read_lock_held());
- *lsn = 0;
-
- /* quick check for stale RCU freed inode */
- if (!ip->i_ino)
- return false;
-
- /*
- * Do unlocked checks to see if the inode already is being flushed or in
- * reclaim to avoid lock traffic. If the inode is not clean, return the
- * it's position in the AIL for the caller to push to.
- */
- if (!xfs_inode_clean(ip)) {
- *lsn = ip->i_itemp->ili_item.li_lsn;
- return false;
- }
-
- if (__xfs_iflags_test(ip, XFS_IFLOCK | XFS_IRECLAIM))
- return false;
-
- /*
- * The radix tree lock here protects a thread in xfs_iget from racing
- * with us starting reclaim on the inode. Once we have the
- * XFS_IRECLAIM flag set it will not touch us.
- *
- * Due to RCU lookup, we may find inodes that have been freed and only
- * have XFS_IRECLAIM set. Indeed, we may see reallocated inodes that
- * aren't candidates for reclaim at all, so we must check the
- * XFS_IRECLAIMABLE is set first before proceeding to reclaim.
- */
- spin_lock(&ip->i_flags_lock);
- if (!__xfs_iflags_test(ip, XFS_IRECLAIMABLE) ||
- __xfs_iflags_test(ip, XFS_IRECLAIM)) {
- /* not a reclaim candidate. */
- spin_unlock(&ip->i_flags_lock);
- return false;
- }
- __xfs_iflags_set(ip, XFS_IRECLAIM);
- spin_unlock(&ip->i_flags_lock);
- return true;
-}
-
-/*
- * Inodes in different states need to be treated differently. The following
- * table lists the inode states and the reclaim actions necessary:
- *
- * inode state iflush ret required action
- * --------------- ---------- ---------------
- * bad - reclaim
- * shutdown EIO unpin and reclaim
- * clean, unpinned 0 reclaim
- * stale, unpinned 0 reclaim
- * clean, pinned(*) 0 requeue
- * stale, pinned EAGAIN requeue
- * dirty, async - requeue
- * dirty, sync 0 reclaim
- *
- * (*) dgc: I don't think the clean, pinned state is possible but it gets
- * handled anyway given the order of checks implemented.
- *
- * Also, because we get the flush lock first, we know that any inode that has
- * been flushed delwri has had the flush completed by the time we check that
- * the inode is clean.
- *
- * Note that because the inode is flushed delayed write by AIL pushing, the
- * flush lock may already be held here and waiting on it can result in very
- * long latencies. Hence for sync reclaims, where we wait on the flush lock,
- * the caller should push the AIL first before trying to reclaim inodes to
- * minimise the amount of time spent waiting. For background relaim, we only
- * bother to reclaim clean inodes anyway.
- *
- * Hence the order of actions after gaining the locks should be:
- * bad => reclaim
- * shutdown => unpin and reclaim
- * pinned, async => requeue
- * pinned, sync => unpin
- * stale => reclaim
- * clean => reclaim
- * dirty, async => requeue
- * dirty, sync => flush, wait and reclaim
- *
- * Returns true if the inode was reclaimed, false otherwise.
- */
-STATIC bool
-xfs_reclaim_inode(
- struct xfs_inode *ip,
- struct xfs_perag *pag,
- xfs_lsn_t *lsn)
-{
- xfs_ino_t ino;
-
- *lsn = 0;
-
- /*
- * Don't try to flush the inode if another inode in this cluster has
- * already flushed it after we did the initial checks in
- * xfs_reclaim_inode_grab().
- */
- if (!xfs_ilock_nowait(ip, XFS_ILOCK_EXCL))
- goto out;
- if (!xfs_iflock_nowait(ip))
- goto out_unlock;
-
- /* If we are in shutdown, we don't care about blocking. */
- if (XFS_FORCED_SHUTDOWN(ip->i_mount)) {
- xfs_iunpin_wait(ip);
- /* xfs_iflush_abort() drops the flush lock */
- xfs_iflush_abort(ip, false);
- goto reclaim;
- }
-
- /*
- * If it is pinned, we only want to flush this if there's nothing else
- * to be flushed as it requires a log force. Hence we essentially set
- * the LSN to flush the entire AIL which will end up triggering a log
- * force to unpin this inode, but that will only happen if there are not
- * other inodes in the scan that only need writeback.
- */
- if (xfs_ipincount(ip)) {
- *lsn = ip->i_itemp->ili_last_lsn;
- goto out_ifunlock;
- }
-
- /*
- * Dirty inode we didn't catch, skip it.
- */
- if (!xfs_inode_clean(ip) && !xfs_iflags_test(ip, XFS_ISTALE)) {
- *lsn = ip->i_itemp->ili_item.li_lsn;
- goto out_ifunlock;
- }
-
- /*
- * It's clean, we have it locked, we can now drop the flush lock
- * and reclaim it.
- */
- xfs_ifunlock(ip);
-
-reclaim:
- ASSERT(!xfs_isiflocked(ip));
- ASSERT(xfs_inode_clean(ip) || xfs_iflags_test(ip, XFS_ISTALE));
- ASSERT(ip->i_ino != 0);
-
- /*
- * Because we use RCU freeing we need to ensure the inode always appears
- * to be reclaimed with an invalid inode number when in the free state.
- * We do this as early as possible under the ILOCK so that
- * xfs_iflush_cluster() and xfs_ifree_cluster() can be guaranteed to
- * detect races with us here. By doing this, we guarantee that once
- * xfs_iflush_cluster() or xfs_ifree_cluster() has locked XFS_ILOCK that
- * it will see either a valid inode that will serialise correctly, or it
- * will see an invalid inode that it can skip.
- */
- spin_lock(&ip->i_flags_lock);
- ino = ip->i_ino; /* for radix_tree_delete */
- ip->i_flags = XFS_IRECLAIM;
- ip->i_ino = 0;
-
- /* XXX: temporary until lru based reclaim */
- list_lru_del(&pag->pag_mount->m_inode_lru, &VFS_I(ip)->i_lru);
- spin_unlock(&ip->i_flags_lock);
-
- xfs_iunlock(ip, XFS_ILOCK_EXCL);
-
- XFS_STATS_INC(ip->i_mount, xs_ig_reclaims);
- /*
- * Remove the inode from the per-AG radix tree.
- *
- * Because radix_tree_delete won't complain even if the item was never
- * added to the tree assert that it's been there before to catch
- * problems with the inode life time early on.
- */
- spin_lock(&pag->pag_ici_lock);
- if (!radix_tree_delete(&pag->pag_ici_root,
- XFS_INO_TO_AGINO(ip->i_mount, ino)))
- ASSERT(0);
- xfs_perag_clear_reclaim_tag(pag);
- spin_unlock(&pag->pag_ici_lock);
-
- /*
- * Here we do an (almost) spurious inode lock in order to coordinate
- * with inode cache radix tree lookups. This is because the lookup
- * can reference the inodes in the cache without taking references.
- *
- * We make that OK here by ensuring that we wait until the inode is
- * unlocked after the lookup before we go ahead and free it.
- */
- xfs_ilock(ip, XFS_ILOCK_EXCL);
- xfs_qm_dqdetach(ip);
- xfs_iunlock(ip, XFS_ILOCK_EXCL);
-
- __xfs_inode_free(ip);
- return true;
-
-out_ifunlock:
- xfs_ifunlock(ip);
-out_unlock:
- xfs_iunlock(ip, XFS_ILOCK_EXCL);
-out:
- xfs_iflags_clear(ip, XFS_IRECLAIM);
- return false;
-}
-
-/*
- * Walk the AGs and reclaim the inodes in them. Even if the filesystem is
- * corrupted, we still want to try to reclaim all the inodes. If we don't,
- * then a shut down during filesystem unmount reclaim walk leak all the
- * unreclaimed inodes.
- *
- * Return the number of inodes freed.
- */
-int
-xfs_reclaim_inodes_ag(
- struct xfs_mount *mp,
- int flags,
- int nr_to_scan)
-{
- struct xfs_perag *pag;
- xfs_agnumber_t ag;
- xfs_lsn_t lsn, lowest_lsn = NULLCOMMITLSN;
- long freed = 0;
-
- ag = 0;
- while ((pag = xfs_perag_get_tag(mp, ag, XFS_ICI_RECLAIM_TAG))) {
- unsigned long first_index = 0;
- int done = 0;
- int nr_found = 0;
-
- ag = pag->pag_agno + 1;
- first_index = pag->pag_ici_reclaim_cursor;
-
- do {
- struct xfs_inode *batch[XFS_LOOKUP_BATCH];
- int i;
-
- rcu_read_lock();
- nr_found = radix_tree_gang_lookup_tag(
- &pag->pag_ici_root,
- (void **)batch, first_index,
- XFS_LOOKUP_BATCH,
- XFS_ICI_RECLAIM_TAG);
- if (!nr_found) {
- done = 1;
- rcu_read_unlock();
- break;
- }
-
- /*
- * Grab the inodes before we drop the lock. if we found
- * nothing, nr == 0 and the loop will be skipped.
- */
- for (i = 0; i < nr_found; i++) {
- struct xfs_inode *ip = batch[i];
-
- if (done ||
- !xfs_reclaim_inode_grab(ip, flags, &lsn))
- batch[i] = NULL;
-
- if (lsn && XFS_LSN_CMP(lsn, lowest_lsn) < 0)
- lowest_lsn = lsn;
-
- /*
- * Update the index for the next lookup. Catch
- * overflows into the next AG range which can
- * occur if we have inodes in the last block of
- * the AG and we are currently pointing to the
- * last inode.
- *
- * Because we may see inodes that are from the
- * wrong AG due to RCU freeing and
- * reallocation, only update the index if it
- * lies in this AG. It was a race that lead us
- * to see this inode, so another lookup from
- * the same index will not find it again.
- */
- if (XFS_INO_TO_AGNO(mp, ip->i_ino) !=
- pag->pag_agno)
- continue;
- first_index = XFS_INO_TO_AGINO(mp, ip->i_ino + 1);
- if (first_index < XFS_INO_TO_AGINO(mp, ip->i_ino))
- done = 1;
- }
-
- /* unlock now we've grabbed the inodes. */
- rcu_read_unlock();
-
- for (i = 0; i < nr_found; i++) {
- if (!batch[i])
- continue;
- if (xfs_reclaim_inode(batch[i], pag, &lsn))
- freed++;
- if (lsn && XFS_LSN_CMP(lsn, lowest_lsn) < 0)
- lowest_lsn = lsn;
- }
-
- nr_to_scan -= XFS_LOOKUP_BATCH;
- cond_resched();
-
- } while (nr_found && !done && nr_to_scan > 0);
-
- if (!done)
- pag->pag_ici_reclaim_cursor = first_index;
- else
- pag->pag_ici_reclaim_cursor = 0;
- xfs_perag_put(pag);
- }
-
- if ((flags & SYNC_WAIT) && lowest_lsn != NULLCOMMITLSN)
- xfs_ail_push_sync(mp->m_ail, lowest_lsn);
-
- return freed;
-}
-
enum lru_status
xfs_inode_reclaim_isolate(
struct list_head *item,
diff --git a/fs/xfs/xfs_icache.h b/fs/xfs/xfs_icache.h
index dadc69a30f33..0b4d06691275 100644
--- a/fs/xfs/xfs_icache.h
+++ b/fs/xfs/xfs_icache.h
@@ -25,9 +25,8 @@ struct xfs_eofblocks {
*/
#define XFS_ICI_NO_TAG (-1) /* special flag for an untagged lookup
in xfs_inode_ag_iterator */
-#define XFS_ICI_RECLAIM_TAG 0 /* inode is to be reclaimed */
-#define XFS_ICI_EOFBLOCKS_TAG 1 /* inode has blocks beyond EOF */
-#define XFS_ICI_COWBLOCKS_TAG 2 /* inode can have cow blocks to gc */
+#define XFS_ICI_EOFBLOCKS_TAG 0 /* inode has blocks beyond EOF */
+#define XFS_ICI_COWBLOCKS_TAG 1 /* inode can have cow blocks to gc */

/*
* Flags for xfs_iget()
@@ -60,8 +59,6 @@ enum lru_status xfs_inode_reclaim_isolate(struct list_head *item,
void xfs_dispose_inodes(struct list_head *freeable);
void xfs_reclaim_inodes(struct xfs_mount *mp);

-void xfs_inode_set_reclaim_tag(struct xfs_inode *ip);
-
void xfs_inode_set_eofblocks_tag(struct xfs_inode *ip);
void xfs_inode_clear_eofblocks_tag(struct xfs_inode *ip);
int xfs_icache_free_eofblocks(struct xfs_mount *, struct xfs_eofblocks *);
diff --git a/fs/xfs/xfs_mount.h b/fs/xfs/xfs_mount.h
index 4a4ecbc22246..ef63357da7af 100644
--- a/fs/xfs/xfs_mount.h
+++ b/fs/xfs/xfs_mount.h
@@ -383,8 +383,6 @@ typedef struct xfs_perag {

spinlock_t pag_ici_lock; /* incore inode cache lock */
struct radix_tree_root pag_ici_root; /* incore inode cache root */
- int pag_ici_reclaimable; /* reclaimable inodes */
- unsigned long pag_ici_reclaim_cursor; /* reclaim restart point */

/* buffer cache index */
spinlock_t pag_buf_lock; /* lock for pag_buf_hash */
diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
index e3e898a2896c..0559fb686e9d 100644
--- a/fs/xfs/xfs_super.c
+++ b/fs/xfs/xfs_super.c
@@ -955,7 +955,6 @@ xfs_fs_destroy_inode(
__xfs_iflags_set(ip, XFS_IRECLAIMABLE);
list_lru_add(&mp->m_inode_lru, &VFS_I(ip)->i_lru);
spin_unlock(&ip->i_flags_lock);
- xfs_inode_set_reclaim_tag(ip);
}

static void
--
2.22.0