I forgot to commit part of the patch. Attached is the patch in full.
David
---
commit a3d01f1a21bcf2c39aa6db49edbc08540378a593
Author: David Howells <dhowells@xxxxxxxxxx>
Date: Mon Dec 13 16:26:44 2021 +0000
afs: Fix mmap
Fix afs_add_open_map() to check that the vnode isn't already on the list
when it adds it. It's possible that afs_drop_open_mmap() decremented the
cb_nr_mmap counter, but hadn't yet got into the locked section to remove
it.
Also vnode->cb_mmap_link should be initialised, so fix that too.
Fixes: 6e0e99d58a65 ("afs: Fix mmap coherency vs 3rd-party changes")
Reported-by: Marc Dionne <marc.dionne@xxxxxxxxxxxx>
Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
cc: linux-afs@xxxxxxxxxxxxxxxxxxx
diff --git a/fs/afs/file.c b/fs/afs/file.c
index 572063dad0b3..bcda99dcfdec 100644
--- a/fs/afs/file.c
+++ b/fs/afs/file.c
@@ -539,8 +539,9 @@ static void afs_add_open_mmap(struct afs_vnode *vnode)
if (atomic_inc_return(&vnode->cb_nr_mmap) == 1) {
down_write(&vnode->volume->cell->fs_open_mmaps_lock);
- list_add_tail(&vnode->cb_mmap_link,
- &vnode->volume->cell->fs_open_mmaps);
+ if (list_empty(&vnode->cb_mmap_link))
+ list_add_tail(&vnode->cb_mmap_link,
+ &vnode->volume->cell->fs_open_mmaps);
up_write(&vnode->volume->cell->fs_open_mmaps_lock);
}
diff --git a/fs/afs/super.c b/fs/afs/super.c
index af7cbd9949c5..5ec9fd97eccc 100644
--- a/fs/afs/super.c
+++ b/fs/afs/super.c
@@ -668,6 +668,7 @@ static void afs_i_init_once(void *_vnode)
INIT_LIST_HEAD(&vnode->pending_locks);
INIT_LIST_HEAD(&vnode->granted_locks);
INIT_DELAYED_WORK(&vnode->lock_work, afs_lock_work);
+ INIT_LIST_HEAD(&vnode->cb_mmap_link);
seqlock_init(&vnode->cb_lock);
}
