ceph: ensure we have Fs caps when fetching dir link count

The link count for a directory is defined as inode->i_subdirs + 2,
(for "." and ".."). i_subdirs is only populated when Fs caps are held.
Ensure we grab Fs caps when fetching the link count for a directory.

[ idryomov: break unnecessarily long line ]

URL: https://tracker.ceph.com/issues/48125
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

diff --git a/fs/ceph/inode.c b/fs/ceph/inode.c
index 02b11a4a4d3934050ed445649da571c9f4bd97b1..12140da244f3757d71dba05afe663e5cb77eb8b6 100644 (file)
--- a/fs/ceph/inode.c
+++ b/fs/ceph/inode.c
@@ -2340,15 +2340,23 @@ int ceph_permission(struct inode *inode, int mask)
 }
 
 /* Craft a mask of needed caps given a set of requested statx attrs. */
-static int statx_to_caps(u32 want)
+static int statx_to_caps(u32 want, umode_t mode)
 {
        int mask = 0;
 
        if (want & (STATX_MODE|STATX_UID|STATX_GID|STATX_CTIME|STATX_BTIME))
                mask |= CEPH_CAP_AUTH_SHARED;
 
-       if (want & (STATX_NLINK|STATX_CTIME))
-               mask |= CEPH_CAP_LINK_SHARED;
+       if (want & (STATX_NLINK|STATX_CTIME)) {
+               /*
+                * The link count for directories depends on inode->i_subdirs,
+                * and that is only updated when Fs caps are held.
+                */
+               if (S_ISDIR(mode))
+                       mask |= CEPH_CAP_FILE_SHARED;
+               else
+                       mask |= CEPH_CAP_LINK_SHARED;
+       }
 
        if (want & (STATX_ATIME|STATX_MTIME|STATX_CTIME|STATX_SIZE|
                    STATX_BLOCKS))
@@ -2374,8 +2382,9 @@ int ceph_getattr(const struct path *path, struct kstat *stat,
 
        /* Skip the getattr altogether if we're asked not to sync */
        if (!(flags & AT_STATX_DONT_SYNC)) {
-               err = ceph_do_getattr(inode, statx_to_caps(request_mask),
-                                     flags & AT_STATX_FORCE_SYNC);
+               err = ceph_do_getattr(inode,
+                               statx_to_caps(request_mask, inode->i_mode),
+                               flags & AT_STATX_FORCE_SYNC);
                if (err)
                        return err;
        }