[PATCH 23/24] xfs: factor xfs_iflush_done

Dave Chinner
2020-05-22T03:50:41Z

From: Dave Chinner <dchinner@redhat.com>

xfs_iflush_done() does 3 distinct operations to the inodes attached
to the buffer. Separate these operations out into functions so that
it is easier to modify these operations independently in future.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
---
fs/xfs/xfs_inode_item.c | 156 +++++++++++++++++++++-------------------
1 file changed, 82 insertions(+), 74 deletions(-)

diff --git a/fs/xfs/xfs_inode_item.c b/fs/xfs/xfs_inode_item.c
index af4764f97a339..4dd4f45dcc46e 100644
--- a/fs/xfs/xfs_inode_item.c
+++ b/fs/xfs/xfs_inode_item.c
@@ -662,104 +662,67 @@ xfs_inode_item_destroy(

/*
- * This is the inode flushing I/O completion routine. It is called
- * from interrupt level when the buffer containing the inode is
- * flushed to disk. It is responsible for removing the inode item
- * from the AIL if it has not been re-logged, and unlocking the inode's
- * flush lock.
- *
- * To reduce AIL lock traffic as much as possible, we scan the buffer log item
- * list for other inodes that will run this function. We remove them from the
- * buffer list so we can process all the inode IO completions in one AIL lock
- * traversal.
- *
- * Note: Now that we attach the log item to the buffer when we first log the
- * inode in memory, we can have unflushed inodes on the buffer list here. These
- * inodes will have a zero ili_last_fields, so skip over them here.
+ * We only want to pull the item from the AIL if it is actually there
+ * and its location in the log has not changed since we started the
+ * flush. Thus, we only bother if the inode's lsn has not changed.
*/
void
-xfs_iflush_done(
- struct xfs_buf *bp)
+xfs_iflush_ail_updates(
+ struct xfs_ail *ailp,
+ struct list_head *list)
{
- struct xfs_inode_log_item *iip;
- struct xfs_log_item *lip, *n;
- struct xfs_ail *ailp = bp->b_mount->m_ail;
- int need_ail = 0;
- LIST_HEAD(tmp);
+ struct xfs_log_item *lip;
+ xfs_lsn_t tail_lsn = 0;

- /*
- * Pull the attached inodes from the buffer one at a time and take the
- * appropriate action on them.
- */
- list_for_each_entry_safe(lip, n, &bp->b_li_list, li_bio_list) {
- iip = INODE_ITEM(lip);
- if (!iip->ili_last_fields)
- continue;
+ /* this is an opencoded batch version of xfs_trans_ail_delete */
+ spin_lock(&ailp->ail_lock);
+ list_for_each_entry(lip, list, li_bio_list) {
+ struct xfs_inode_log_item *iip = INODE_ITEM(lip);
+ xfs_lsn_t lsn;

- if (xfs_iflags_test(iip->ili_inode, XFS_ISTALE)) {
- xfs_iflush_abort(iip->ili_inode);
+ if (iip->ili_flush_lsn != lip->li_lsn) {
+ xfs_clear_li_failed(lip);
continue;
}

- list_move_tail(&lip->li_bio_list, &tmp);
-
- /* Do an unlocked check for needing the AIL lock. */
- if (iip->ili_flush_lsn == lip->li_lsn ||
- test_bit(XFS_LI_FAILED, &lip->li_flags))
- need_ail++;
+ lsn = xfs_ail_delete_one(ailp, lip);
+ if (!tail_lsn && lsn)
+ tail_lsn = lsn;
}
+ xfs_ail_update_finish(ailp, tail_lsn);
+}

- /*
- * We only want to pull the item from the AIL if it is actually there
- * and its location in the log has not changed since we started the
- * flush. Thus, we only bother if the inode's lsn has not changed.
- */
- if (need_ail) {
- xfs_lsn_t tail_lsn = 0;
-
- /* this is an opencoded batch version of xfs_trans_ail_delete */
- spin_lock(&ailp->ail_lock);
- list_for_each_entry(lip, &tmp, li_bio_list) {
- iip = INODE_ITEM(lip);
- if (iip->ili_flush_lsn == lip->li_lsn) {
- xfs_lsn_t lsn = xfs_ail_delete_one(ailp, lip);
- if (!tail_lsn && lsn)
- tail_lsn = lsn;
- } else {
- xfs_clear_li_failed(lip);
- }
- }
- xfs_ail_update_finish(ailp, tail_lsn);
- }
+/*
+ * Walk the list of inodes that have completed their IOs. If they are clean
+ * remove them from the list and dissociate them from the buffer. Buffers that
+ * are still dirty remain linked to the buffer and on the list. Caller must
+ * handle them appropriately.
+ */
+void
+xfs_iflush_finish(
+ struct xfs_buf *bp,
+ struct list_head *list)
+{
+ struct xfs_log_item *lip, *n;

- /*
- * Clean up and unlock the flush lock now we are done. We can clear the
- * ili_last_fields bits now that we know that the data corresponding to
- * them is safely on disk.
- */
- list_for_each_entry_safe(lip, n, &tmp, li_bio_list) {
+ list_for_each_entry_safe(lip, n, list, li_bio_list) {
+ struct xfs_inode_log_item *iip = INODE_ITEM(lip);
bool drop_buffer = false;

- list_del_init(&lip->li_bio_list);
- iip = INODE_ITEM(lip);
-
spin_lock(&iip->ili_lock);
iip->ili_last_fields = 0;
iip->ili_flush_lsn = 0;

/*
* Remove the reference to the cluster buffer if the inode is
- * clean in memory. Drop the buffer reference once we've dropped
- * the locks we hold. If the inode is dirty in memory, we need
- * to put the inode item back on the buffer list for another
- * pass through the flush machinery.
+ * clean in memory and drop the buffer reference once we've
+ * dropped the locks we hold.
*/
ASSERT(iip->ili_item.li_buf == bp);
if (!iip->ili_fields) {
iip->ili_item.li_buf = NULL;
+ list_del_init(&lip->li_bio_list);
drop_buffer = true;
- } else {
- list_add(&lip->li_bio_list, &bp->b_li_list);
}
spin_unlock(&iip->ili_lock);
xfs_ifunlock(iip->ili_inode);
@@ -768,6 +731,51 @@ xfs_iflush_done(
}
}

+/*
+ * Inode buffer IO completion routine. It is responsible for removing inodes
+ * attached to the buffer from the AIL if they have not been re-logged, as well
+ * as completing the flush and unlocking the inode.
+ */
+void
+xfs_iflush_done(
+ struct xfs_buf *bp)
+{
+ struct xfs_log_item *lip, *n;
+ LIST_HEAD(flushed_inodes);
+ LIST_HEAD(ail_updates);
+
+ /*
+ * Pull the attached inodes from the buffer one at a time and take the
+ * appropriate action on them.
+ */
+ list_for_each_entry_safe(lip, n, &bp->b_li_list, li_bio_list) {
+ struct xfs_inode_log_item *iip = INODE_ITEM(lip);
+ if (!iip->ili_last_fields)
+ continue;
+
+ if (xfs_iflags_test(iip->ili_inode, XFS_ISTALE)) {
+ xfs_iflush_abort(iip->ili_inode);
+ continue;
+ }
+
+ /* Do an unlocked check for needing the AIL lock. */
+ if (iip->ili_flush_lsn == lip->li_lsn ||
+ test_bit(XFS_LI_FAILED, &lip->li_flags))
+ list_move_tail(&lip->li_bio_list, &ail_updates);
+ else
+ list_move_tail(&lip->li_bio_list, &flushed_inodes);
+ }
+
+ if (!list_empty(&ail_updates)) {
+ xfs_iflush_ail_updates(bp->b_mount->m_ail, &ail_updates);
+ list_splice_tail(&ail_updates, &flushed_inodes);
+ }
+
+ xfs_iflush_finish(bp, &flushed_inodes);
+ if (!list_empty(&flushed_inodes))
+ list_splice_tail(&flushed_inodes, &bp->b_li_list);
+}
+
/*
* This is the inode flushing abort routine. It is called from xfs_iflush when
* the filesystem is shutting down to clean up the inode state. It is
--
2.26.2.761.g0e0b3e54be