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: 6e0e99d58a ("afs: Fix mmap coherency vs 3rd-party changes")
Reported-by: kafs-testing+fedora34_64checkkafs-build-300@auristor.com
Suggested-by: Marc Dionne <marc.dionne@auristor.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by: kafs-testing+fedora34_64checkkafs-build-300@auristor.com
cc: linux-afs@lists.infradead.org
Link: https://lore.kernel.org/r/686465.1639435380@warthog.procyon.org.uk/ # v1
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
David Howells 2021-12-14 09:22:12 +00:00 committed by Linus Torvalds
parent 2b14864acb
commit 1744a22ae9
2 changed files with 4 additions and 2 deletions

View File

@ -514,8 +514,9 @@ 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);
}

View File

@ -667,6 +667,7 @@ 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);
}