[PATCH v4 14/16] bcachefs: add pre-content fsnotify hook to fault

Josef Bacik
2024-08-14T21:26:20Z

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.

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..1fa1f1ac48c8 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_maybe_emit_fsnotify_event(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