[PATCH v5 15/18] bcachefs: add pre-content fsnotify hook to fault

[Josef Bacik <josef@toxicpanda.com>]

bcachefs has its own locking around filemap_fault, so we have to make
sure we do the fsnotify hook before the locking.  Add the check to emit
the event before the locking and return VM_FAULT_RETRY to retrigger the
fault once the event has been emitted.

Acked-by: Kent Overstreet <kent.overstreet@linux.dev>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
---
 fs/bcachefs/fs-io-pagecache.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/fs/bcachefs/fs-io-pagecache.c b/fs/bcachefs/fs-io-pagecache.c
index a9cc5cad9cc9..ce7968e4fd2f 100644
--- a/fs/bcachefs/fs-io-pagecache.c
+++ b/fs/bcachefs/fs-io-pagecache.c
@@ -570,6 +570,10 @@ vm_fault_t bch2_page_fault(struct vm_fault *vmf)
 	if (fdm == mapping)
 		return VM_FAULT_SIGBUS;
 
+	ret = filemap_fsnotify_fault(vmf);
+	if (unlikely(ret))
+		return ret;
+
 	/* Lock ordering: */
 	if (fdm > mapping) {
 		struct bch_inode_info *fdm_host = to_bch_ei(fdm->host);
-- 
2.43.0