iget/iget5: don't bother with ->i_lock until we find a match

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 8 insertions, 0 deletions

diff --git a/Documentation/filesystems/porting b/Documentation/filesystems/porting
index f0890581f7f6..fe2b7ae6f962 100644
--- a/Documentation/filesystems/porting
+++ b/Documentation/filesystems/porting
@@ -455,3 +455,11 @@ in your dentry operations instead.
         vfs_follow_link has been removed.  Filesystems must use nd_set_link
         from ->follow_link for normal symlinks, or nd_jump_link for magic
         /proc/<pid> style links.
+--
+[mandatory]
+        iget5_locked()/ilookup5()/ilookup5_nowait() test() callback used to be
+        called with both ->i_lock and inode_hash_lock held; the former is *not*
+        taken anymore, so verify that your callbacks do not rely on it (none
+        of the in-tree instances did).  inode_hash_lock is still held,
+        of course, so they are still serialized wrt removal from inode hash,
+        as well as wrt set() callback of iget5_locked().