This is a note to let you know that I've just added the patch titled
dax: Avoid losing wakeup in dax_lock_mapping_entry
to the 4.19-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
dax-avoid-losing-wakeup-in-dax_lock_mapping_entry.patch
and it can be found in the queue-4.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 25bbe21bf427a81b8e3ccd480ea0e1d940256156 Mon Sep 17 00:00:00 2001
From: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Date: Fri, 16 Nov 2018 15:50:02 -0500
Subject: dax: Avoid losing wakeup in dax_lock_mapping_entry
From: Matthew Wilcox <willy@xxxxxxxxxxxxx>
commit 25bbe21bf427a81b8e3ccd480ea0e1d940256156 upstream.
After calling get_unlocked_entry(), you have to call
put_unlocked_entry() to avoid subsequent waiters losing wakeups.
Fixes: c2a7d2a11552 ("filesystem-dax: Introduce dax_lock_mapping_entry()")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/dax.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -217,6 +217,9 @@ static inline void *unlock_slot(struct a
return (void *)entry;
}
+static void put_unlocked_mapping_entry(struct address_space *mapping,
+ pgoff_t index, void *entry);
+
/*
* Lookup entry in radix tree, wait for it to become unlocked if it is
* exceptional entry and return it. The caller must call
@@ -256,8 +259,10 @@ static void *__get_unlocked_mapping_entr
revalidate = wait_fn();
finish_wait(wq, &ewait.wait);
xa_lock_irq(&mapping->i_pages);
- if (revalidate)
+ if (revalidate) {
+ put_unlocked_mapping_entry(mapping, index, entry);
return ERR_PTR(-EAGAIN);
+ }
}
}
Patches currently in stable-queue which might be from willy@xxxxxxxxxxxxx are
queue-4.19/bfs-add-sanity-check-at-bfs_fill_super.patch
queue-4.19/dax-avoid-losing-wakeup-in-dax_lock_mapping_entry.patch
