iomap: share iomap_unshare_iter predicate code with fsdax
[ Upstream commit 6ef6a0e821d3dad6bf8a5d5508762dba9042c84b ]
The predicate code that iomap_unshare_iter uses to decide if it's really
needs to unshare a file range mapping should be shared with the fsdax
version, because right now they're opencoded and inconsistent.
Note that we simplify the predicate logic a bit -- we no longer allow
unsharing of inline data mappings, but there aren't any filesystems that
allow shared inline data currently.
This is a fix in the sense that it should have been ported to fsdax.
Fixes: b53fdb215d13 ("iomap: improve shared block detection in iomap_unshare_iter")
Signed-off-by: Darrick J. Wong <[email protected]>
Link: https://lore.kernel.org/r/172796813294.1131942.15762084021076932620.stgit@frogsfrogsfrogs
Reviewed-by: Christoph Hellwig <[email protected]>
Signed-off-by: Christian Brauner <[email protected]>
Stable-dep-of: 50793801fc7f ("fsdax: dax_unshare_iter needs to copy entire blocks")
Signed-off-by: Sasha Levin <[email protected]>
diff --git a/fs/dax.c b/fs/dax.c
index d48b4fc..2f7f5e2 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -1268,8 +1268,7 @@ static s64 dax_unshare_iter(struct iomap_iter *iter)
s64 ret = 0;
void *daddr = NULL, *saddr = NULL;
- /* don't bother with blocks that are not shared to start with */
- if (!(iomap->flags & IOMAP_F_SHARED))
+ if (!iomap_want_unshare_iter(iter))
return length;
id = dax_read_lock();
