On Wed, Jun 20, 2018 at 4:51 PM Chengguang Xu <cgxu519@xxxxxxx> wrote:
>
> When the size of acl extended attribution is larger than pre-allocated
> value buffer size, we will hit error '-ERANGE' and it's probabaly caused
> by concurrent get/set acl from different clients. In this case, current
> logic just sets acl to NULL so that we cannot get proper information but
> the operation looks successful.
>
> This patch adds retry logic for error -ERANGE and return -EIO if fail
> from the retry. Additionally, print real errno when failing from
> __ceph_getxattr().
>
> Signed-off-by: Chengguang Xu <cgxu519@xxxxxxx>
> ---
> v2:
> - Increase retry count to 10.
> - Print real errno when failing from __ceph_getxattr().
>
Applied, thanks
Yan, Zheng
> fs/ceph/acl.c | 17 ++++++++++++++---
> 1 file changed, 14 insertions(+), 3 deletions(-)
>
> diff --git a/fs/ceph/acl.c b/fs/ceph/acl.c
> index 59cb307b15fb..28290ac409d2 100644
> --- a/fs/ceph/acl.c
> +++ b/fs/ceph/acl.c
> @@ -45,6 +45,7 @@ static inline void ceph_set_cached_acl(struct inode *inode,
> struct posix_acl *ceph_get_acl(struct inode *inode, int type)
> {
> int size;
> + unsigned int retry_cnt = 0;
> const char *name;
> char *value = NULL;
> struct posix_acl *acl;
> @@ -60,6 +61,7 @@ struct posix_acl *ceph_get_acl(struct inode *inode, int type)
> BUG();
> }
>
> +retry:
> size = __ceph_getxattr(inode, name, "", 0);
> if (size > 0) {
> value = kzalloc(size, GFP_NOFS);
> @@ -68,12 +70,21 @@ struct posix_acl *ceph_get_acl(struct inode *inode, int type)
> size = __ceph_getxattr(inode, name, value, size);
> }
>
> - if (size > 0)
> + if (size == -ERANGE && retry_cnt < 10) {
> + retry_cnt++;
> + kfree(value);
> + value = NULL;
> + goto retry;
> + }
> +
> + if (size > 0) {
> acl = posix_acl_from_xattr(&init_user_ns, value, size);
> - else if (size == -ERANGE || size == -ENODATA || size == 0)
> + } else if (size == -ENODATA || size == 0) {
> acl = NULL;
> - else
> + } else {
> + pr_err_ratelimited("get acl failed, errno = %d\n", size);
> acl = ERR_PTR(-EIO);
> + }
>
> kfree(value);
>
> --
> 2.17.1
>
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