Merge tag 'fsnotify_for_v6.14-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs

Pull fsnotify reverts from Jan Kara:
 "Syzbot has found out that fsnotify HSM events generated on page fault
  can be generated while we already hold freeze protection for the
  filesystem (when you do buffered write from a buffer which is mmapped
  file on the same filesystem) which violates expectations for HSM
  events and could lead to deadlocks of HSM clients with filesystem
  freezing.

  Since it's quite late in the cycle we've decided to revert changes
  implementing HSM events on page fault for now and instead just
  generate one event for the whole range on mmap(2) so that HSM client
  can fetch the data at that moment"

* tag 'fsnotify_for_v6.14-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs:
  Revert "fanotify: disable readahead if we have pre-content watches"
  Revert "mm: don't allow huge faults for files with pre content watches"
  Revert "fsnotify: generate pre-content permission event on page fault"
  Revert "xfs: add pre-content fsnotify hook for DAX faults"
  Revert "ext4: add pre-content fsnotify hook for DAX faults"
  fsnotify: add pre-content hooks on mmap()

2 files changed, 21 insertions, 1 deletions

diff --git a/include/linux/fsnotify.h b/include/linux/fsnotify.h
index 6a33288bd6a1..83d3ac97f826 100644
--- a/include/linux/fsnotify.h
+++ b/include/linux/fsnotify.h
@@ -171,6 +171,21 @@ static inline int fsnotify_file_area_perm(struct file *file, int perm_mask,
 }
 
 /*
+ * fsnotify_mmap_perm - permission hook before mmap of file range
+ */
+static inline int fsnotify_mmap_perm(struct file *file, int prot,
+				     const loff_t off, size_t len)
+{
+	/*
+	 * mmap() generates only pre-content events.
+	 */
+	if (!file || likely(!FMODE_FSNOTIFY_HSM(file->f_mode)))
+		return 0;
+
+	return fsnotify_pre_content(&file->f_path, &off, len);
+}
+
+/*
  * fsnotify_truncate_perm - permission hook before file truncate
  */
 static inline int fsnotify_truncate_perm(const struct path *path, loff_t length)
@@ -223,6 +238,12 @@ static inline int fsnotify_file_area_perm(struct file *file, int perm_mask,
 	return 0;
 }
 
+static inline int fsnotify_mmap_perm(struct file *file, int prot,
+				     const loff_t off, size_t len)
+{
+	return 0;
+}
+
 static inline int fsnotify_truncate_perm(const struct path *path, loff_t length)
 {
 	return 0;
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 7b1068ddcbb7..8483e09aeb2c 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -3420,7 +3420,6 @@ extern vm_fault_t filemap_fault(struct vm_fault *vmf);
 extern vm_fault_t filemap_map_pages(struct vm_fault *vmf,
 		pgoff_t start_pgoff, pgoff_t end_pgoff);
 extern vm_fault_t filemap_page_mkwrite(struct vm_fault *vmf);
-extern vm_fault_t filemap_fsnotify_fault(struct vm_fault *vmf);
 
 extern unsigned long stack_guard_gap;
 /* Generic expand stack which grows the stack according to GROWS{UP,DOWN} */