Re: [PATCH 5.10 004/161] btrfs: send: check for inline extents in range_is_hole_in_parent()

David Sterba
2026-02-05T13:51:20Z

On Wed, Feb 04, 2026 at 07:28:42PM +0100, Ben Hutchings wrote:
> On Wed, 2026-02-04 at 15:37 +0100, Greg Kroah-Hartman wrote:
> > 5.10-stable review patch. If anyone has any objections, please let me know.
> >
> > ------------------
> >
> > From: Qu Wenruo <wqu@suse.com>
> >
> > [ Upstream commit 08b096c1372cd69627f4f559fb47c9fb67a52b39 ]
> >
> > Before accessing the disk_bytenr field of a file extent item we need
> > to check if we are dealing with an inline extent.
> > This is because for inline extents their data starts at the offset of
> > the disk_bytenr field. So accessing the disk_bytenr
> > means we are accessing inline data or in case the inline data is less
> > than 8 bytes we can actually cause an invalid
> > memory access if this inline extent item is the first item in the leaf
> > or access metadata from other items.
> >
> > Fixes: 82bfb2e7b645 ("Btrfs: incremental send, fix unnecessary hole writes for sparse files")
> > Reviewed-by: Filipe Manana <fdmanana@suse.com>
> > Signed-off-by: Qu Wenruo <wqu@suse.com>
> > Reviewed-by: David Sterba <dsterba@suse.com>
> > Signed-off-by: David Sterba <dsterba@suse.com>
> > Signed-off-by: Sasha Levin <sashal@kernel.org>
> > ---
> > fs/btrfs/send.c | 2 ++
> > 1 file changed, 2 insertions(+)
> >
> > diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c
> > index d86b4d13cae48..f144171ed6b7e 100644
> > --- a/fs/btrfs/send.c
> > +++ b/fs/btrfs/send.c
> > @@ -5892,6 +5892,8 @@ static int range_is_hole_in_parent(struct send_ctx *sctx,
> > extent_end = btrfs_file_extent_end(path);
> > if (extent_end <= start)
> > goto next;
> > + if (btrfs_file_extent_type(leaf, fi) == BTRFS_FILE_EXTENT_INLINE)
> > + return 0;
>
> This will leak path, unless (at least) commits 4c74a32ad323 "btrfs:
> DEFINE_FREE for struct btrfs_path" and 4ca6f24a52c4 "btrfs: more trivial
> BTRFS_PATH_AUTO_FREE conversions" are also backported.
>
> That could be avoided by using { ret = 0; goto out; } here instead of
> simply returning.

Right, the original patch assumes the automatic cleanup of btrfs_path, so
for anything below it needs to be updated as you say.