On 10.12.18 г. 19:53 ч., fdmanana@xxxxxxxxxx wrote:
> From: Filipe Manana <fdmanana@xxxxxxxx>
>
> When initializing the security xattrs, we are holding a transaction handle
> therefore we need to use a GFP_NOFS context in order to avoid a deadlock
> with reclaim in case it's triggered.
>
> Fixes: 39a27ec1004e8 ("btrfs: use GFP_KERNEL for xattr and acl allocations")
> Signed-off-by: Filipe Manana <fdmanana@xxxxxxxx>
Reviewed-by: Nikolay Borisov <nborisov@xxxxxxxx>
> ---
> fs/btrfs/xattr.c | 8 ++++++++
> 1 file changed, 8 insertions(+)
>
> diff --git a/fs/btrfs/xattr.c b/fs/btrfs/xattr.c
> index ea78c3d6dcfc..f141b45ce349 100644
> --- a/fs/btrfs/xattr.c
> +++ b/fs/btrfs/xattr.c
> @@ -11,6 +11,7 @@
> #include <linux/security.h>
> #include <linux/posix_acl_xattr.h>
> #include <linux/iversion.h>
> +#include <linux/sched/mm.h>
> #include "ctree.h"
> #include "btrfs_inode.h"
> #include "transaction.h"
> @@ -422,9 +423,15 @@ static int btrfs_initxattrs(struct inode *inode,
> {
> const struct xattr *xattr;
> struct btrfs_trans_handle *trans = fs_info;
> + unsigned int nofs_flag;
> char *name;
> int err = 0;
>
> + /*
> + * We're holding a transaction handle, so use a NOFS memory allocation
> + * context to avoid deadlock if reclaim happens.
> + */
> + nofs_flag = memalloc_nofs_save();
> for (xattr = xattr_array; xattr->name != NULL; xattr++) {
> name = kmalloc(XATTR_SECURITY_PREFIX_LEN +
> strlen(xattr->name) + 1, GFP_KERNEL);
> @@ -440,6 +447,7 @@ static int btrfs_initxattrs(struct inode *inode,
> if (err < 0)
> break;
> }
> + memalloc_nofs_restore(nofs_flag);
> return err;
> }
>
>
