[RFC PATCH] ceph: add ceph.caps vxattr

[Luis Henriques]

Add a new vxattr that allows userspace to list the caps for a specific
directory or file.

Signed-off-by: Luis Henriques <lhenriq...@suse.de>
---
 fs/ceph/xattr.c | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/fs/ceph/xattr.c b/fs/ceph/xattr.c
index 197cb1234341..996512e05513 100644
--- a/fs/ceph/xattr.c
+++ b/fs/ceph/xattr.c
@@ -303,6 +303,18 @@ static ssize_t ceph_vxattrcb_snap_btime(struct 
ceph_inode_info *ci, char *val,
                                ci->i_snap_btime.tv_nsec);
 }
 
+static ssize_t ceph_vxattrcb_caps(struct ceph_inode_info *ci, char *val,
+                                       size_t size)
+{
+       int issued;
+
+       spin_lock(&ci->i_ceph_lock);
+       issued = __ceph_caps_issued(ci, NULL);
+       spin_unlock(&ci->i_ceph_lock);
+
+       return ceph_fmt_xattr(val, size, "%s", ceph_cap_string(issued));
+}
+
 #define CEPH_XATTR_NAME(_type, _name)  XATTR_CEPH_PREFIX #_type "." #_name
 #define CEPH_XATTR_NAME2(_type, _name, _name2) \
        XATTR_CEPH_PREFIX #_type "." #_name "." #_name2
@@ -378,6 +390,13 @@ static struct ceph_vxattr ceph_dir_vxattrs[] = {
                .exists_cb = ceph_vxattrcb_snap_btime_exists,
                .flags = VXATTR_FLAG_READONLY,
        },
+       {
+               .name = "ceph.caps",
+               .name_size = sizeof("ceph.caps"),
+               .getxattr_cb = ceph_vxattrcb_caps,
+               .exists_cb = NULL,
+               .flags = VXATTR_FLAG_HIDDEN,
+       },
        { .name = NULL, 0 }     /* Required table terminator */
 };
 
@@ -403,6 +422,13 @@ static struct ceph_vxattr ceph_file_vxattrs[] = {
                .exists_cb = ceph_vxattrcb_snap_btime_exists,
                .flags = VXATTR_FLAG_READONLY,
        },
+       {
+               .name = "ceph.caps",
+               .name_size = sizeof("ceph.caps"),
+               .getxattr_cb = ceph_vxattrcb_caps,
+               .exists_cb = NULL,
+               .flags = VXATTR_FLAG_HIDDEN,
+       },
        { .name = NULL, 0 }     /* Required table terminator */
 };