[PATCH 5/5] btrfs: use GFP_NOWAIT when inhibiting eb writeback

Inhibition allocation is already best effort and done while holding
locks so switch it to NOWAIT.

Signed-off-by: Boris Burkov <[email protected]>
---
 fs/btrfs/extent_io.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index b40d3c47eb0d..43c361ef61a2 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -3002,10 +3002,11 @@ static inline void btrfs_release_extent_buffer(struct extent_buffer *eb)
  * @trans:  transaction handle that will own the inhibitor
  * @eb:      extent buffer to inhibit writeback on
  *
- * Attempt to track this extent buffer in the transaction's inhibited set.  If
- * memory allocation fails, the buffer is simply not tracked. It may be written
- * back and need re-COW, which is the original behavior.  This is acceptable
- * since inhibiting writeback is an optimization.
+ * Attempt to track this extent buffer in the transaction's inhibited set.  We
+ * are called under eb->lock, so try with GFP_NOWAIT rather than entering
+ * reclaim under the lock.  If the allocation fails, the buffer is simply not
+ * tracked. It may be written back and need re-COW, which is the original
+ * behavior. This is acceptable since inhibiting writeback is an optimization.
  */
 void btrfs_inhibit_eb_writeback(struct btrfs_trans_handle *trans, struct extent_buffer *eb)
 {
@@ -3021,7 +3022,7 @@ void btrfs_inhibit_eb_writeback(struct btrfs_trans_handle *trans, struct extent_
 	/* Take reference for the xarray entry. */
 	refcount_inc(&eb->refs);
 
-	old = xa_store(&trans->writeback_inhibited_ebs, index, eb, GFP_NOFS);
+	old = xa_store(&trans->writeback_inhibited_ebs, index, eb, GFP_NOWAIT);
 	if (xa_is_err(old)) {
 		/* Allocation failed, just skip inhibiting this buffer. */
 		free_extent_buffer(eb);
-- 
2.54.0