5.0-stable review patch. If anyone has any objections, please let me know.
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From: Filipe Manana fdmanana@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: stable@vger.kernel.org # 4.9+ Reviewed-by: Nikolay Borisov nborisov@suse.com Signed-off-by: Filipe Manana fdmanana@suse.com Reviewed-by: David Sterba dsterba@suse.com Signed-off-by: David Sterba dsterba@suse.com Signed-off-by: Greg Kroah-Hartman gregkh@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;