xfs_trans_brelse() is a bit of a historical mess, similar to
xfs_buf_item_unlock(). It is unnecessarily verbose, has snippets of
commented out code, inconsistency with regard to stale items, etc.
Clean up xfs_trans_brelse() to use similar logic and flow as
xfs_buf_item_unlock() with regard to bli reference count handling.
This patch makes no functional changes, but facilitates further
refactoring of the common bli reference count handling code.
Signed-off-by: Brian Foster <bfoster@xxxxxxxxxx>
---
fs/xfs/xfs_trans_buf.c | 108 +++++++++++++++--------------------------
1 file changed, 38 insertions(+), 70 deletions(-)
diff --git a/fs/xfs/xfs_trans_buf.c b/fs/xfs/xfs_trans_buf.c
index 15919f67a88f..92a708cdfee3 100644
--- a/fs/xfs/xfs_trans_buf.c
+++ b/fs/xfs/xfs_trans_buf.c
@@ -322,49 +322,40 @@ xfs_trans_read_buf_map(
}
/*
- * Release the buffer bp which was previously acquired with one of the
- * xfs_trans_... buffer allocation routines if the buffer has not
- * been modified within this transaction. If the buffer is modified
- * within this transaction, do decrement the recursion count but do
- * not release the buffer even if the count goes to 0. If the buffer is not
- * modified within the transaction, decrement the recursion count and
- * release the buffer if the recursion count goes to 0.
+ * Release a buffer previously joined to the transaction. If the buffer is
+ * modified within this transaction, decrement the recursion count but do not
+ * release the buffer even if the count goes to 0. If the buffer is not modified
+ * within the transaction, decrement the recursion count and release the buffer
+ * if the recursion count goes to 0.
*
- * If the buffer is to be released and it was not modified before
- * this transaction began, then free the buf_log_item associated with it.
+ * If the buffer is to be released and it was not already dirty before this
+ * transaction began, then also free the buf_log_item associated with it.
*
- * If the transaction pointer is NULL, make this just a normal
- * brelse() call.
+ * If the transaction pointer is NULL, this is a normal xfs_buf_relse() call.
*/
void
xfs_trans_brelse(
- xfs_trans_t *tp,
- xfs_buf_t *bp)
+ struct xfs_trans *tp,
+ struct xfs_buf *bp)
{
- struct xfs_buf_log_item *bip;
- int freed;
+ struct xfs_buf_log_item *bip = bp->b_log_item;
+ bool freed;
+ bool dirty;
- /*
- * Default to a normal brelse() call if the tp is NULL.
- */
- if (tp == NULL) {
- ASSERT(bp->b_transp == NULL);
+ ASSERT(bp->b_transp == tp);
+
+ if (!tp) {
xfs_buf_relse(bp);
return;
}
- ASSERT(bp->b_transp == tp);
- bip = bp->b_log_item;
+ trace_xfs_trans_brelse(bip);
ASSERT(bip->bli_item.li_type == XFS_LI_BUF);
- ASSERT(!(bip->bli_flags & XFS_BLI_STALE));
- ASSERT(!(bip->__bli_format.blf_flags & XFS_BLF_CANCEL));
ASSERT(atomic_read(&bip->bli_refcount) > 0);
- trace_xfs_trans_brelse(bip);
-
/*
- * If the release is just for a recursive lock,
- * then decrement the count and return.
+ * If the release is for a recursive lookup, then decrement the count
+ * and return.
*/
if (bip->bli_recur > 0) {
bip->bli_recur--;
@@ -372,63 +363,40 @@ xfs_trans_brelse(
}
/*
- * If the buffer is dirty within this transaction, we can't
+ * If the buffer is invalidated or dirty in this transaction, we can't
* release it until we commit.
*/
if (test_bit(XFS_LI_DIRTY, &bip->bli_item.li_flags))
return;
-
- /*
- * If the buffer has been invalidated, then we can't release
- * it until the transaction commits to disk unless it is re-dirtied
- * as part of this transaction. This prevents us from pulling
- * the item from the AIL before we should.
- */
if (bip->bli_flags & XFS_BLI_STALE)
return;
- ASSERT(!(bip->bli_flags & XFS_BLI_LOGGED));
-
/*
- * Free up the log item descriptor tracking the released item.
+ * Unlink the log item from the transaction and clear the hold flag, if
+ * set. We wouldn't want the next user of the buffer to get confused.
*/
+ ASSERT(!(bip->bli_flags & XFS_BLI_LOGGED));
xfs_trans_del_item(&bip->bli_item);
-
- /*
- * Clear the hold flag in the buf log item if it is set.
- * We wouldn't want the next user of the buffer to
- * get confused.
- */
- if (bip->bli_flags & XFS_BLI_HOLD) {
+ if (bip->bli_flags & XFS_BLI_HOLD)
bip->bli_flags &= ~XFS_BLI_HOLD;
- }
/*
- * Drop our reference to the buf log item.
+ * Drop the reference to the bli. At this point, the bli must be either
+ * freed or dirty (or both). If freed, there are a couple cases where we
+ * are responsible to free the item. If the bli is clean, we're the last
+ * user of it. If the fs has shut down, the bli may be dirty and AIL
+ * resident, but won't ever be written back.
*/
freed = atomic_dec_and_test(&bip->bli_refcount);
-
- /*
- * If the buf item is not tracking data in the log, then we must free it
- * before releasing the buffer back to the free pool.
- *
- * If the fs has shutdown and we dropped the last reference, it may fall
- * on us to release a (possibly dirty) bli if it never made it to the
- * AIL (e.g., the aborted unpin already happened and didn't release it
- * due to our reference). Since we're already shutdown and need
- * ail_lock, just force remove from the AIL and release the bli here.
- */
- if (XFS_FORCED_SHUTDOWN(tp->t_mountp) && freed) {
- xfs_trans_ail_remove(&bip->bli_item, SHUTDOWN_LOG_IO_ERROR);
- xfs_buf_item_relse(bp);
- } else if (!(bip->bli_flags & XFS_BLI_DIRTY)) {
-/***
- ASSERT(bp->b_pincount == 0);
-***/
- ASSERT(atomic_read(&bip->bli_refcount) == 0);
- ASSERT(!test_bit(XFS_LI_IN_AIL, &bip->bli_item.li_flags));
- ASSERT(!(bip->bli_flags & XFS_BLI_INODE_ALLOC_BUF));
- xfs_buf_item_relse(bp);
+ dirty = bip->bli_flags & XFS_BLI_DIRTY;
+ ASSERT(freed || dirty);
+ if (freed) {
+ bool abort = XFS_FORCED_SHUTDOWN(tp->t_mountp);
+ ASSERT(abort || !test_bit(XFS_LI_IN_AIL, &bip->bli_item.li_flags));
+ if (abort)
+ xfs_trans_ail_remove(&bip->bli_item, SHUTDOWN_LOG_IO_ERROR);
+ if (!dirty || abort)
+ xfs_buf_item_relse(bp);
}
bp->b_transp = NULL;
--
2.17.1
