5.0-stable review patch. If anyone has any objections, please let me know.
------------------ From: Filipe Manana <fdman...@suse.com> commit a0873490660246db587849a9e172f2b7b21fa88a upstream. We are holding a transaction handle when setting an acl, therefore we can not allocate the xattr value buffer using GFP_KERNEL, as we could deadlock if reclaim is triggered by the allocation, therefore setup a nofs context. Fixes: 39a27ec1004e8 ("btrfs: use GFP_KERNEL for xattr and acl allocations") CC: sta...@vger.kernel.org # 4.9+ Reviewed-by: Nikolay Borisov <nbori...@suse.com> Signed-off-by: Filipe Manana <fdman...@suse.com> Reviewed-by: David Sterba <dste...@suse.com> Signed-off-by: David Sterba <dste...@suse.com> Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org> --- fs/btrfs/acl.c | 9 +++++++++ 1 file changed, 9 insertions(+) --- a/fs/btrfs/acl.c +++ b/fs/btrfs/acl.c @@ -9,6 +9,7 @@ #include <linux/posix_acl_xattr.h> #include <linux/posix_acl.h> #include <linux/sched.h> +#include <linux/sched/mm.h> #include <linux/slab.h> #include "ctree.h" @@ -72,8 +73,16 @@ static int __btrfs_set_acl(struct btrfs_ } if (acl) { + unsigned int nofs_flag; + size = posix_acl_xattr_size(acl->a_count); + /* + * We're holding a transaction handle, so use a NOFS memory + * allocation context to avoid deadlock if reclaim happens. + */ + nofs_flag = memalloc_nofs_save(); value = kmalloc(size, GFP_KERNEL); + memalloc_nofs_restore(nofs_flag); if (!value) { ret = -ENOMEM; goto out;